CN212210538U

CN212210538U - Three-bridge-arm topology device and uninterruptible power supply system

Info

Publication number: CN212210538U
Application number: CN202020885385.5U
Authority: CN
Inventors: 罗峰
Original assignee: Guangzhou Shiyuan Electronics Thecnology Co Ltd; Guangzhou Shikun Electronic Technology Co Ltd
Current assignee: Guangzhou Shiyuan Electronics Thecnology Co Ltd; Guangzhou Shikun Electronic Technology Co Ltd
Priority date: 2020-05-22
Filing date: 2020-05-22
Publication date: 2020-12-22
Anticipated expiration: 2030-05-22
Also published as: WO2021232749A1

Abstract

The utility model provides a topological device of three bridge arms and uninterrupted power source system, the topological device of three bridge arms passes through multiplexing voltage conversion circuit, like this, does not need additionally to add the charger and can realize the function of charging to the group battery. In addition, no matter in the mains supply mode or the battery supply mode, the voltage conversion circuit and the three-bridge arm change circuit are all involved in working, namely all devices of the three-bridge arm topology device are all involved in working. When the three-bridge-arm topological device is applied to a battery low-voltage large-current uninterruptible power supply system, the device reuse rate of the system can be improved, the device design redundancy is avoided, and the cost of the battery low-voltage large-current uninterruptible power supply system is further reduced.

Description

Three-bridge-arm topology device and uninterruptible power supply system

Technical Field

The utility model relates to an uninterrupted power source technique especially relates to a three-bridge arm topology device and uninterrupted power source system.

Background

An on-line Uninterruptible Power Supply (UPS) system is a UPS system in which the ac voltage used by a load passes through an inverter circuit regardless of whether the grid voltage is normal or not. According to the power division, the online UPS systems are divided into an online medium-low power UPS system and an online high-power UPS system. The online medium and small power UPS system is usually an online UPS system with power between 1 kilowatt and 3 kilowatts.

The battery low-voltage large-current UPS system is an on-line medium-small power UPS system, and the battery pack of the UPS system has a small number of batteries, and can output low-voltage large-current electric energy when the battery pack is used for supplying power to a load. Because the battery pack used by the battery low-voltage large-current UPS system has few battery sections, the battery low-voltage large-current UPS system is widely applied to the field of online medium-and small-power UPS. However, the device reuse rate of the conventional battery low-voltage high-current UPS system is low, which results in high cost of the battery low-voltage high-current UPS system.

SUMMERY OF THE UTILITY MODEL

The utility model provides a topological device of three bridge arms and uninterrupted power source system for solve the lower technical problem of device reuse rate of current battery low pressure heavy current UPS system.

In a first aspect, the utility model provides a three-bridge arm topology device, three-bridge arm topology device includes: the device comprises a battery pack, a voltage conversion circuit, a change-over switch and a three-bridge arm conversion circuit;

the three-bridge arm conversion circuit includes: the bridge comprises a first bridge arm, a second bridge arm, a third bridge arm, a first inductor, a second inductor, a direct current bus capacitor and a first capacitor; the first bridge arm comprises a first switching tube and a second switching tube which are connected in series; the second bridge arm comprises a third switching tube and a fourth switching tube which are connected in series; the third bridge arm comprises a fifth switching tube and a sixth switching tube which are connected in series; the first bridge arm, the second bridge arm, the third bridge arm and the direct current bus capacitor are connected in parallel between a positive output end and a negative output end of a bus; the midpoint of the first bridge arm is connected with the first end of the first inductor, and the second end of the first inductor is connected as a positive voltage input end of the three-bridge arm topology device; the middle point of the second bridge arm is connected as a negative voltage input end of the three-bridge-arm topological device; the middle point of the third bridge arm is connected with the first end of the second inductor, the second end of the second inductor is the output end of the three-bridge-arm topological device and is respectively connected with a load and the first end of the first capacitor, and the second end of the first capacitor is connected with the negative voltage input end;

the battery pack is connected with the first end of the voltage conversion circuit, the positive electrode of the second end of the voltage conversion circuit is respectively connected with the positive output end of the bus and the positive voltage input end through the change-over switch, the negative electrode of the second end of the voltage conversion circuit is connected with the negative output end of the bus, the live wire of the commercial power alternating-current power supply is connected with the positive voltage input end through the change-over switch, and the zero line of the commercial power alternating-current power supply is connected with the negative voltage input end; the change-over switch is used for controlling the voltage conversion circuit to charge the battery pack in a mains supply mode; and when in a battery power supply mode, controlling the voltage conversion circuit to discharge the battery pack.

In a first possible implementation manner, the switch includes: the circuit comprises a first switch, a second switch and a balance component; the positive electrode of the second end of the voltage conversion circuit is connected with the fixed end of the first switch, the first selection end of the first switch is connected with the first end of the balance component, the second end of the balance component is connected with the positive output end of the bus, the second selection end of the first switch is connected with the positive voltage input end, the first end of the second switch is connected with the live wire of the commercial power alternating-current power supply, the second end of the second switch is connected with the positive voltage input end, and the negative electrode of the second end of the voltage conversion circuit is connected with the negative output end of the bus; the balance component is used for balancing the voltage between the bus and the voltage conversion circuit; when the mains supply mode is adopted, the fixed end of the first switch is communicated with the first selection end of the first switch, and the second switch is closed; when the battery power supply mode is adopted, the fixed end of the first switch is communicated with the second selection end of the first switch, and the second switch is disconnected.

Optionally, the first switch is any one of: double throw relay, two-way electronic switch, thyristor. Optionally, the second switch is any one of: single throw relay, one-way electronic switch, thyristor. Optionally, the balance component is any one of the following components: a piezoresistor, a thermistor with negative temperature coefficient and a third inductor.

Optionally, the balance component is a resistor, and the switch further includes: a third switch; the positive electrode of the second end of the voltage conversion circuit is connected with the first end of the third switch, and the second end of the third switch is connected with the positive output end of the bus; or, the third switch is connected in parallel with the resistor; when the commercial power supply mode is adopted and the voltage difference value between the bus and the voltage conversion circuit is smaller than or equal to a preset threshold value, the third switch is closed; in the battery powered mode, the third switch is open. Optionally, the third switch is any one of: single throw relay, one-way electronic switch, thyristor.

In a second possible implementation manner, the switch includes: the circuit comprises a first switch, a second switch and a balance component; the positive electrode of the second end of the voltage conversion circuit is connected with the first end of the first switch and the first selection end of the second switch respectively, the second end of the first switch is connected with the first end of the balance component, the second end of the balance component is connected with the positive output end of the bus, the second selection end of the second switch is connected with the live wire of the commercial power alternating-current power supply, the fixed end of the second switch is connected with the positive voltage input end, and the negative electrode of the second end of the voltage conversion circuit is connected with the negative output end of the bus; the balance component is used for balancing the voltage between the bus and the voltage conversion circuit; when the commercial power supply mode is adopted, the first switch is closed, and the fixed end of the second switch is communicated with the second selection end of the second switch; and when the battery is in the power supply mode, the first switch is disconnected, and the fixed end of the second switch is communicated with the first selection end of the second switch.

Optionally, the first switch is any one of: single throw relay, one-way electronic switch, thyristor. Optionally, the second switch is any one of: double throw relay, two-way electronic switch, thyristor. Optionally, the balance component is any one of the following components: a piezoresistor, a thermistor with negative temperature coefficient and a third inductor.

In a third possible implementation manner, the switch includes: the first switch, the second switch, the third switch and the balance component; the positive electrode of the second end of the voltage conversion circuit is respectively connected with the first end of the first switch and the first end of the third switch, the second end of the first switch is connected with the positive voltage input end, the first end of the second switch is connected with the live wire of the commercial power alternating-current power supply, the second end of the second switch is connected with the positive voltage input end, the second end of the third switch is connected with the first end of the balance component, the second end of the balance component is connected with the positive output end of the bus, and the negative electrode of the second end of the voltage conversion circuit is connected with the negative output end of the bus; the balance component is used for balancing the voltage between the bus and the voltage conversion circuit; when the mains supply mode is started, the first switch is closed, and the second switch is opened; in the battery powered mode, the first switch is closed and the second switch and the third switch are open.

Optionally, the first switch is any one of: single throw relay, one-way electronic switch, thyristor. Optionally, the second switch is any one of: single throw relay, one-way electronic switch, thyristor. Optionally, the third switch is any one of: single throw relay, one-way electronic switch, thyristor. Optionally, the balance component is any one of the following components: a piezoresistor, a thermistor with negative temperature coefficient and a third inductor.

Optionally, the balance component is a resistor, and the switch further includes: a fourth switch; the positive electrode of the second end of the voltage conversion circuit is connected with the first end of the fourth switch, and the second end of the fourth switch is connected with the positive output end of the bus; or, the fourth switch is connected in parallel with the resistor; when the commercial power supply mode is adopted and the voltage difference value between the bus and the voltage conversion circuit is smaller than or equal to a preset threshold value, the fourth switch is closed; in the battery powered mode, the fourth switch is open. Optionally, the fourth switch is any one of: single throw relay, one-way electronic switch, thyristor.

In a fourth possible implementation manner, the voltage conversion circuit includes: the bridge comprises a fourth bridge arm, a fifth bridge arm, a sixth bridge arm, a seventh bridge arm, a transformer, a third inductor, a second capacitor and a third capacitor;

the fourth bridge arm comprises a seventh switching tube and an eighth switching tube, and the first end of the seventh switching tube is connected with the first end of the eighth switching tube;

the fifth bridge arm comprises a ninth switching tube and a tenth switching tube, and the first end of the ninth switching tube is connected with the first end of the tenth switching tube;

the sixth bridge arm comprises an eleventh switching tube and a twelfth switching tube, and the first end of the eleventh switching tube is connected with the first end of the twelfth switching tube;

the seventh bridge arm comprises a thirteenth switching tube and a fourteenth switching tube, and the first end of the thirteenth switching tube is connected with the first end of the fourteenth switching tube;

the fourth bridge arm and the fifth bridge arm are connected in parallel, the sixth bridge arm and the seventh bridge arm are connected in parallel with the third capacitor, the first end of the transformer is connected with the midpoint of the fourth bridge arm, the second end of the transformer is connected with the midpoint of the fifth bridge arm, the third end of the transformer is connected with the midpoint of the fifth bridge arm through the third inductor and the second capacitor, and the fourth end of the transformer is connected with the midpoint of the sixth bridge arm;

the second end of the seventh switching tube is the positive electrode of the first end of the voltage conversion circuit, the second end of the eighth switching tube is the negative electrode of the first end of the voltage conversion circuit, the second end of the thirteenth switching tube is the positive electrode of the second end of the voltage conversion circuit, and the second end of the fourteenth switching tube is the negative electrode of the second end of the voltage conversion circuit.

In a second aspect, the present invention also provides an uninterruptible power supply system, the system includes: a mains ac power supply, a load, and a three-limb topology as described in any of the first aspects; the live wire of the commercial power alternating-current power supply is connected with the positive voltage input end of the three-bridge arm topology device, the zero wire of the commercial power alternating-current power supply is connected with the negative voltage input end of the three-bridge arm topology device, and the output end of the three-bridge arm topology device is connected with the load.

The utility model provides a three-bridge arm topology device and uninterrupted power system realize charging or discharging of group battery through multiplexing voltage conversion circuit, do not need additionally to add the charger and can realize the function of charging to the group battery. In addition, no matter in the mains supply mode or the battery supply mode, the voltage conversion circuit and the three-bridge arm change circuit are all involved in working, namely all devices of the three-bridge arm topology device are all involved in working. When the three-bridge-arm topological device is applied to the battery low-voltage large-current UPS system, the device reuse rate of the system can be improved, the device design redundancy is avoided, and the cost of the battery low-voltage large-current UPS system is further reduced.

Drawings

In order to more clearly illustrate the technical solutions of the present invention or the prior art, the following briefly introduces the drawings needed to be used in the description of the embodiments or the prior art, and obviously, the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without inventive labor.

Fig. 1 is a schematic structural diagram of a battery low-voltage high-current UPS system provided in the prior art;

fig. 2 is a first schematic diagram of a first three-arm topology device provided by the present invention;

fig. 3 is a second schematic diagram of a first three-arm topology apparatus provided by the present invention;

fig. 4 is a schematic diagram of a second three-arm topology apparatus provided by the present invention;

fig. 5 is a schematic diagram of a third bridge arm topology apparatus provided by the present invention;

fig. 6 is a schematic diagram of a fourth three-bridge-arm topology apparatus provided by the present invention;

fig. 7 is a schematic diagram of a fifth three-arm topology apparatus provided by the present invention;

fig. 8 is a schematic current diagram of a fourth three-bridge-arm topology device provided by the present invention in a mains power supply mode;

fig. 9 is a schematic current diagram of a fourth three-bridge-arm topology device provided by the present invention in a mains power supply mode;

fig. 10 is a schematic current diagram of a fourth three-bridge-arm topology device provided by the present invention in a mains power supply mode;

fig. 11 is a schematic current diagram of a fourth three-bridge-arm topology device provided by the present invention in a mains power supply mode;

fig. 12 is a schematic current diagram of a fourth three-bridge-arm topology device provided by the present invention in a battery-powered mode;

fig. 13 is a schematic current diagram of a fourth three-bridge-arm topology device provided by the present invention in a battery power supply mode;

fig. 14 is a schematic view of a sixth three-arm topology apparatus provided by the present invention;

fig. 15 is a schematic view of a seventh three-arm topology apparatus provided by the present invention;

fig. 16 is a schematic diagram of an eighth three-arm topology apparatus provided by the present invention;

fig. 17 is a schematic view of a ninth three-arm topology apparatus provided by the present invention;

fig. 18 is a schematic view of a tenth three-arm topology apparatus provided by the present invention;

fig. 19 is a schematic diagram of an eleventh three-arm topology apparatus provided by the present invention;

fig. 20 is a schematic diagram of a twelfth three-arm topology apparatus provided in the present invention;

fig. 21 is a schematic diagram of a thirteenth three-leg topology device provided by the present invention;

fig. 22 is a schematic diagram of a fourteenth three-leg topology device provided by the present invention;

fig. 23 is a schematic diagram of a fifteenth three-arm topology device provided by the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clearer, the accompanying drawings in the embodiments of the present invention are combined below to clearly and completely describe the technical solutions in the embodiments of the present invention, and obviously, the described embodiments are some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.

Fig. 1 is a schematic structural diagram of a battery low-voltage high-current UPS system provided in the prior art. As shown in fig. 1, a conventional battery low-voltage high-current UPS system includes: the power supply comprises a charger, a battery pack, a unidirectional Direct Current (DC-DC) converter, a commercial power Alternating Current (AC), a Vienna rectifier converter and a half-bridge inverter.

In a mains supply mode (i.e., when AC is supplied), the vienna rectifier converter converts a mains AC power supply into dc power, the half-bridge inverter converts the dc power into AC power and supplies the AC power to a load, and the charger charges the battery pack. In the mains supply mode, the vienna rectifier converter, the half-bridge inverter and the charger are engaged, and in this mode, the DC-DC converter is in an idle state.

In a battery power supply mode (i.e., when the battery pack supplies power), the DC-DC converter boosts the DC power output by the battery pack, and the half-bridge inverter converts the DC power into ac power and supplies the ac power to the load. That is, the DC-DC converter and the half-bridge inverter participate in operation. In the battery-powered mode, the vienna rectifier converter and the charger are idle.

That is to say, when the existing battery low-voltage large-current UPS system works, part of devices are in an idle state, so that the device reuse rate of the existing battery low-voltage large-current UPS system is low, and the cost of the battery low-voltage large-current UPS system is high.

In view of the above problems, an embodiment of the present application provides a three-bridge-arm topology device, and when the device is applied to a battery low-voltage large-current UPS system, no matter in a mains supply mode or in a battery supply mode, all devices of the device all participate in working, so that the device reuse rate of the battery low-voltage large-current UPS system is improved, and further, the cost of the battery low-voltage large-current UPS system is reduced.

The technical solution of the present invention will be described in detail with reference to specific embodiments. The following several specific embodiments may be combined with each other, and details of the same or similar concepts or processes may not be repeated in some embodiments.

Fig. 2 is a first schematic diagram of a three-arm topology apparatus provided by the present invention. As shown in fig. 2, the three-arm topology device may include: the device comprises a battery pack, a voltage conversion circuit, a change-over switch and a three-bridge arm conversion circuit.

The three-bridge arm conversion circuit may include: the bridge circuit comprises a first bridge arm, a second bridge arm, a third bridge arm, a first inductor L1, a second inductor L2, a direct-current bus capacitor E1 and a first capacitor Co.

The first bridge arm comprises a first switch tube Q1 and a second switch tube Q2, the first switch tube Q1 and the second switch tube Q2 are connected in series between a BUS + and a BUS-, the BUS + is a positive output end of a BUS, and the BUS-is a negative output end of the BUS. For example, a first end of the first switch tube Q1 is connected to BUS +, a second end of the first switch tube Q1 is connected to a first end of the second switch tube Q2, and a second end of the second switch tube Q2 is connected to BUS-. The common end of the first switch tube Q1 and the second switch tube Q2 is referred to as the midpoint of the first leg. In some embodiments, the first leg may also be referred to as a Power Factor Correction (PFC) side high frequency leg.

The second bridge arm comprises a third switching tube Q3 and a fourth switching tube Q4, and the third switching tube Q3 and the fourth switching tube Q4 are connected between BUS + and BUS-in series. For example, a first end of the third switching tube Q3 is connected to BUS +, a second end of the third switching tube Q3 is connected to a first end of the fourth switching tube Q4, and a second end of the fourth switching tube Q4 is connected to BUS-. The common end of the third switching tube Q3 and the fourth switching tube Q4 is referred to as the midpoint of the second leg. In some embodiments, the second leg may also be referred to as a leg shared by a PFC and an Inverter (INV).

The third bridge arm comprises a fifth switch tube Q5 and a sixth switch tube Q6, and the fifth switch tube Q5 and the sixth switch tube Q6 are connected in series between BUS + and BUS-. For example, a first end of the fifth switching tube Q5 is connected to BUS +, a second end of the fifth switching tube Q5 is connected to a first end of the sixth switching tube Q6, and a second end of the sixth switching tube Q6 is connected to BUS-. The common end of the fifth switching tube Q5 and the sixth switching tube Q6 is referred to as the midpoint of the third leg. In some embodiments, the third leg may also be referred to as an INV-side high frequency leg.

DC BUS capacitor E1 is connected between BUS + and BUS-. That is, first leg, second leg, third leg, and dc BUS capacitor E1 are connected in parallel between BUS + and BUS-.

The first inductor L1 is a high-frequency inductor on the PFC side, and the second inductor L2 is a high-frequency inductor on the INV side. The midpoint of the first bridge arm is connected to the first end of the first inductor L1, and the second end of the first inductor L1 serves as the positive voltage input AC _ L of the three-bridge arm topology device. And the middle point of the second bridge arm is used as a negative voltage input end AC _ N of the three-bridge-arm topological device. The midpoint of the third bridge arm is connected to the first end of a second inductor L2, the second end of the second inductor L2 is the output end of the three-bridge-arm topology device, and is connected to the load and the first end of a first capacitor Co, and the second end of the first capacitor Co is connected to the negative voltage input end AC _ N.

The positive pole of the battery pack is connected with the positive pole of the first end of the voltage conversion circuit, and the negative pole of the battery pack is connected with the negative pole of the first end of the voltage conversion circuit. The positive pole of the second end of the voltage conversion circuit is connected with a BUS + and the positive voltage input end AC _ L through a change-over switch respectively, the negative pole of the second end of the voltage conversion circuit is connected with a BUS-, the live wire of the commercial power alternating current power supply AC is connected with the positive voltage input end AC _ L through the change-over switch, and the zero line of the commercial power alternating current power supply AC is connected with the negative voltage input end AC _ N.

The battery pack may include at least one battery, and may be determined according to the power of a UPS system to which the three-arm topology apparatus is applied, for example, the UPS system may be an online UPS system with a power between 1 kw and 3 kw, or the UPS may be a battery low-voltage high-current UPS system.

In this embodiment, the three-bridge topology device has two power supply modes, which are respectively: mains supply mode and battery supply mode. The mains supply mode may be a mode in which a mains alternating current power supply AC supplies stable mains; the battery power supply mode may be a mode in which power is supplied by a battery pack of the UPS system, and at this time, commercial power input by the commercial power AC power supply is low voltage, or there is no commercial power input. The three-arm topology can be switched between the two modes by switching the switches.

Under the mains supply mode, the change-over switch can control the mains supply alternating current power supply AC to supply power for the three-bridge arm conversion circuit. At this time, the three-arm conversion circuit operates in an AC-AC mode. For example, the PFC of the three-bridge arm conversion circuit converts alternating current input from the AC mains supply into direct current (i.e., rectifies the alternating current input from the AC mains supply), the dc bus capacitor E1 filters (may also be referred to as voltage stabilization) the direct current obtained by conversion of the PFC to obtain stable direct current, and the INV of the three-bridge arm conversion circuit converts the stable direct current into alternating current and outputs the alternating current to the load to supply power to the load.

Although the PFC converts ac power into dc power, the dc power still contains a certain pulsating ac component, which is referred to as a ripple voltage. Therefore, in the utility power supply mode, the dc bus capacitor E1 may filter (may also be referred to as a voltage stabilizing) the dc power converted by the PFC to filter the ripple voltage in the dc power, so as to obtain a smooth and stable dc voltage. Meanwhile, the direct current bus capacitor E1 can store energy.

Under the mains supply mode, the change-over switch can control the voltage conversion circuit to charge the battery pack. For example, the switch may control the voltage conversion circuit to charge the battery pack when the battery pack is in the low voltage mode. Namely, the charging of the battery pack is realized by multiplexing the voltage conversion circuit, and no additional charger is needed. At this time, in the commercial power supply mode, the voltage conversion circuit and the three-bridge arm change circuit both participate in the work, that is, all devices of the three-bridge arm topology device participate in the work.

For example, the change-over switch may control the voltage conversion circuit to be hung between the BUS + and the BUS-, the voltage conversion circuit operates in a BUCK mode (i.e., a step-down mode), and performs step-down processing on a BUS voltage (i.e., a voltage obtained by filtering direct current obtained by converting PFC by the direct current BUS capacitor E1) output by the direct current BUS capacitor E1 to obtain a charging voltage of the battery pack, so as to charge the battery pack with the charging voltage. At this time, the battery pack serves as an output source of the voltage conversion circuit.

Referring to fig. 1, when a battery pack is charged by a charger in the prior art, the charger needs to be provided with: the alternating current rectifier circuit is used for rectifying alternating current provided by a commercial alternating current power supply to obtain direct current. The voltage reduction circuit is used for carrying out voltage reduction treatment on the direct current to obtain the charging voltage of the battery pack. Because the alternating current that commercial power alternating current power supply provided has the undulant condition of wide voltage range, consequently, the step-down circuit that sets up in the charger needs to realize the wide range voltage regulation, leads to step-down circuit's voltage conversion efficiency lower, consequently, when adopting the charger to charge for the group battery, the charging efficiency of charger is lower.

And in the embodiment of the utility model provides an in, the stable DC voltage that the BUS voltage of direct current BUS electric capacity E1 output obtained for the PFC rectification through three bridge arm converting circuit, consequently, when using the BUS voltage of direct current BUS electric capacity E1 output to charge for the group battery, can multiplexing voltage converting circuit carries out step-down processing to the BUS voltage of direct current BUS electric capacity E1 output, and need not to set up rectifier circuit alone again. Or, the PFC of the three-bridge arm conversion circuit is multiplexed to obtain direct current for charging the battery pack.

In addition, because the BUS voltage output by the direct current BUS capacitor E1 is stable direct current, the BUS voltage output by the direct current BUS capacitor E1 can be subjected to voltage reduction processing without using a voltage conversion circuit with wide voltage regulation range, the conversion efficiency of the voltage conversion circuit is improved, and the charging efficiency of the battery pack is further improved.

In the battery power supply mode, the switch can control the voltage conversion circuit to discharge the battery pack. For example, the switch may control the voltage conversion circuit to switch on between the high frequency inductor (i.e., the first inductor L1) and the BUS-on the PFC side. At this time, the voltage conversion circuit is connected in series with a Boost circuit formed by the first inductor L1 and the first arm of the three-arm inverter circuit, and two-stage Boost processing is realized when discharging the battery pack. Specifically, the voltage conversion circuit operates in a Boost mode (i.e., a Boost mode), and performs a first-stage Boost process on the output voltage of the battery pack, the first inductor L1 and the first bridge arm of the three-bridge arm conversion circuit form the Boost circuit, the output voltage of the battery pack is subjected to a second-stage Boost process, and the boosted voltage is input to the dc bus capacitor E1 of the three-bridge arm conversion circuit to maintain the bus voltage balance.

In a UPS system with low-voltage and high-current batteries, the battery pack outputs a low voltage, and the load requires a high voltage. Therefore, when the three-arm topology device is applied to a UPS system with low-voltage and high-current batteries, the three-arm topology device needs to boost a lower voltage to a higher voltage, that is, needs to perform a boosting process with a larger voltage difference when the UPS system with low-voltage and high-current batteries uses a battery pack to supply power to a load. If the voltage conversion circuit is connected in parallel with the "first inductor L1 and the Boost circuit formed by the first arm of the three-arm conversion circuit" to perform the boosting operation using only the voltage conversion circuit (i.e., to perform the one-stage boosting process using the voltage conversion circuit), there are the following problems:

1. the voltage conversion circuit has a limitation of a maximum voltage boosting ratio (for example, the output voltage is divided by the input voltage), which may cause the voltage conversion circuit to use the voltage boosted by the maximum voltage boosting ratio, which is still smaller than the voltage required by the load of the UPS system with low voltage and large current of the battery, and thus cannot meet the use requirement of the UPS system with low voltage and large current of the battery.

2. The higher the step-up ratio, the lower the conversion efficiency of the voltage conversion circuit, and the greater the risk of current stress and heat loss of the voltage conversion circuit. Therefore, the above-mentioned first-stage boosting process using the voltage conversion circuit requires the voltage conversion circuit to perform a boosting process with a high boosting ratio, which results in low conversion efficiency of the voltage conversion circuit and high risk of current stress and heat loss of the voltage conversion circuit.

In view of the above-mentioned problem that uses voltage conversion circuit to carry out the one-level processing of stepping up exists, the utility model discloses a constitute Boost circuit "series connection with voltage conversion circuit and" first inductance L1 and three bridge arm converting circuit's first bridge arm and realize the mode that the two-stage was stepped up, can make the Boost circuit that first inductance L1 and three bridge arm converting circuit's first bridge arm constitute share the operation that a part of voltage steps up to when obtaining great step-up ratio, can make voltage conversion circuit itself need not to carry out the processing of stepping up of great pressure difference again. When the voltage difference between the input voltage and the output voltage of the voltage conversion circuit is smaller, that is, the boosting ratio is smaller, the voltage conversion efficiency of the voltage conversion circuit is higher. Therefore, the conversion efficiency of the voltage conversion circuit can be improved by the two-stage boosting mode, the current stress risk and the heat loss risk of the voltage conversion circuit are further reduced, and the reliability of the UPS system with the low-voltage and large-current battery is improved.

In the battery power supply mode, the battery pack is an input source of the voltage conversion circuit, and the output of the voltage conversion circuit supplies power for the three-bridge arm conversion circuit. At this time, the three-arm conversion circuit operates in a DC-AC mode. For example, a first bridge arm and a first inductor L1 of the three-bridge arm conversion circuit operate in a Boost mode, the dc bus capacitor E1 filters the boosted dc power to obtain a stable dc power, and the third bridge arm operates in an inverter mode, converts the stable dc power into an ac power and outputs the ac power to a load to supply power to the load. Meanwhile, the direct current bus capacitor E1 can store energy. At this time, in the battery power supply mode, the voltage conversion circuit and the three-bridge arm change circuit both participate in the operation, that is, all devices of the three-bridge arm topology device participate in the operation.

It can be understood that the voltage conversion circuit according to the embodiment of the present invention may be any circuit having a bidirectional voltage conversion function. Such as a voltage conversion circuit with soft switching, a voltage conversion circuit with hard switching, etc. The voltage conversion circuit may be a voltage conversion circuit with electrical isolation or a voltage conversion circuit without electrical isolation. Illustratively, the voltage conversion circuit may also be referred to as a DC-DC converter.

Fig. 3 is a second schematic diagram of a first three-bridge arm topology device provided by the present invention, as shown in fig. 3, for example, a voltage conversion circuit according to an embodiment of the present invention may include: the bridge circuit comprises a fourth bridge arm, a fifth bridge arm, a sixth bridge arm, a seventh bridge arm, a transformer TX11, a third inductor L3, a second capacitor C2 and a third capacitor E2.

The fourth bridge arm comprises a seventh switch tube Q7 and an eighth switch tube Q8, and a first end of the seventh switch tube Q7 is connected with a first end of the eighth switch tube Q8. At this time, a common end of the seventh switching tube Q7 and the eighth switching tube Q8 is referred to as a midpoint of the fourth arm.

The fifth bridge arm comprises a ninth switching tube Q9 and a tenth switching tube Q10, and the first end of the ninth switching tube Q9 is connected with the first end of the tenth switching tube Q10. At this time, a common end of the ninth switching tube Q9 and the tenth switching tube Q10 is referred to as a midpoint of the fifth arm.

The sixth bridge arm comprises an eleventh switch tube Q11 and a twelfth switch tube Q12, and a first end of the eleventh switch tube Q11 is connected with a first end of the twelfth switch tube Q12. At this time, a common end of the eleventh switching tube Q11 and the twelfth switching tube Q12 is referred to as a midpoint of the sixth arm.

The seventh bridge arm comprises a thirteenth switching tube Q13 and a fourteenth switching tube Q14, and a first end of the thirteenth switching tube Q13 is connected with a first end of the fourteenth switching tube Q14. At this time, the common end of the thirteenth switching tube Q13 and the fourteenth switching tube Q14 is referred to as the midpoint of the seventh leg.

And the fourth bridge arm is connected with the fifth bridge arm in parallel. For example, the second terminal of the seventh switching tube Q7 is connected to the second terminal of the ninth switching tube Q9, and the second terminal of the eighth switching tube Q8 is connected to the second terminal of the tenth switching tube Q10.

The sixth leg, the seventh leg, and the third capacitor E2 are connected in parallel. For example, the second terminal of the eleventh switch tube Q11 is connected to the second terminal of the thirteenth switch tube Q13 and the first terminal of the third capacitor E2, and the second terminal of the twelfth switch tube Q12 is connected to the second terminal of the fourteenth switch tube Q14 and the second terminal of the third capacitor E2. It should be understood that the third capacitor E2 may be a dc capacitor for providing a filtering function to provide stable dc power when the voltage converting circuit charges or discharges the battery pack.

A first end a of the transformer TX11 is connected to the midpoint of the fourth leg, a second end B of the transformer TX11 is connected to the midpoint of the fifth leg, a third end C of the transformer TX11 is connected to the midpoint of the fifth leg through the third inductor L3 and the second capacitor C2, and a fourth end D of the transformer TX11 is connected to the midpoint of the sixth leg.

In the voltage converting circuit, the second terminal of the seventh switching tube Q7 is the positive terminal of the first terminal of the voltage converting circuit, the second terminal of the eighth switching tube Q8 is the negative terminal of the first terminal of the voltage converting circuit, the second terminal of the thirteenth switching tube Q13 is the positive terminal of the second terminal of the voltage converting circuit, and the second terminal of the fourteenth switching tube Q14 is the negative terminal of the second terminal of the voltage converting circuit.

When the battery pack is charged using the voltage conversion circuit shown in fig. 3, Q11, Q12, Q13, and Q14 function as switching tubes, and external diodes (also referred to as parasitic diodes or the like) of Q7, Q8, Q9, and Q10 function as rectifiers. Q11 and Q14 are simultaneously conducted, and Q12 and Q13 are simultaneously conducted. For example, the battery pack may be charged by a constant-frequency and constant-duty control method. The constant duty ratio here means that the same duty ratio is used for control so that the on periods of Q11 and Q14 are the same as the on periods of Q12 and Q13. The fixed frequency here means that the fixed frequency is used for voltage regulation control.

When the battery pack is discharged using the voltage conversion circuit shown in fig. 3, Q7, Q8, Q9, and Q10 function as switching tubes, and external diodes (also referred to as parasitic diodes or the like) of Q11, Q12, Q13, and Q14 function as rectifiers. Wherein, Q7 and Q10 are simultaneously conducted, and Q8 and Q9 are simultaneously conducted. For example, the battery pack may be discharged by a variable-frequency constant-duty control method. The constant duty ratio here means that Q7, Q8, Q9, and Q10 are controlled using the same duty ratio so that the on-periods of Q7 and Q10 are the same as the on-periods of Q8 and Q9. The frequency conversion here means voltage regulation control by frequency conversion.

By the structure of the voltage conversion circuit, the soft switching of the voltage conversion circuit can be realized. Soft-Switching (Soft-Switching) is a Switching technology relative to Hard-Switching (Hard-Switching). The soft switching technology can make the switch tube in the voltage conversion circuit reduce the voltage to zero before switching on, and reduce the current to zero before switching off (namely zero voltage switching on and zero current switching off) to eliminate the overlapping of the voltage and the current of the switch tube in the switching process and reduce the change rate of the voltage and the current, thereby greatly reducing or even eliminating the switching loss of the voltage conversion circuit and realizing the high frequency of the voltage conversion circuit.

The voltage regulating capability of the voltage conversion circuit with the soft switch is poor. That is to say, when the voltage conversion circuit realizes voltage regulation with a large voltage difference, the voltage conversion circuit can only realize zero-voltage turn-on and cannot realize zero-current turn-off, so that the voltage conversion circuit cannot realize soft switching under the full working condition of zero-voltage turn-on and zero-current turn-off, that is, the voltage conversion circuit cannot work under the full working condition of zero-voltage turn-on and zero-current turn-off, and further the conversion efficiency of the voltage conversion circuit is lower than that under the full working condition, and the current stress risk and the heat loss risk of the voltage conversion circuit are increased.

Therefore, when being applied to the three-bridge-arm topology device provided by the embodiment of the present invention, in a manner of connecting the voltage conversion circuit and the first bridge arm of the "first inductor L1 and three-bridge-arm conversion circuit in series to form the Boost circuit", the voltage conversion circuit can realize the soft switching function of a fixed Boost ratio (for example, the fixed Boost ratio can realize the voltage regulation of a smaller voltage difference), and the Boost circuit composed of the first inductor L1 and the first bridge arm of the three-bridge-arm conversion circuit realizes the voltage regulation function, that is, when obtaining a larger Boost ratio, the voltage conversion circuit itself having the soft switch can be made to be free from executing the Boost processing of a larger voltage difference. Therefore, the voltage conversion circuit with the soft switch can work under the full working condition of zero-voltage switching-on and zero-current switching-off, the conversion efficiency of the voltage conversion circuit with the soft switch is improved, the current stress risk and the heat loss risk of the voltage conversion circuit with the soft switch are further reduced, and the reliability of the UPS system with the battery low-voltage and large current is improved.

It should be understood that fig. 3 is only one schematic of the voltage conversion circuit with soft switch, and in particular, other voltage conversion circuits with soft switch may also be adopted in the embodiment of the present invention, which is not described herein again.

In addition, although fig. 3 is a schematic diagram illustrating a voltage converting circuit provided with electrical isolation (for example, the transformer in fig. 3 realizes electrical isolation of the voltage converting circuit), it should be understood that the voltage converting circuit according to the embodiment of the present invention may be a voltage converting circuit with electrical isolation, or a voltage converting circuit without electrical isolation. For example, the voltage conversion circuit has electrical isolation, the first leg of the three-leg conversion circuit has no electrical isolation, or the voltage conversion circuit has no electrical isolation, the first leg of the three-leg conversion circuit has electrical isolation, or the voltage conversion circuit has no electrical isolation, the first leg of the three-leg conversion circuit has no electrical isolation, or the like.

It should be noted that, when the three-leg topology device is switched from the commercial power supply mode to the battery power supply mode, or when the three-leg topology device is switched from the battery power supply mode to the commercial power supply mode, because there is a certain time difference in mode switching (for example, there may be a time difference of X seconds from the commercial power being turned off to the battery pack being powered), within the time difference, the three-leg topology device may use the voltage stored in the dc bus capacitor E1 to supply power to the load, so as to provide stable ac power for the load, and avoid power failure of the load.

The embodiment of the utility model provides a three bridge arm topology devices through multiplexing voltage conversion circuit, realizes charging or discharging of group battery through voltage conversion circuit promptly, does not need additionally to add the charger and can realize the function of charging to the group battery. In addition, no matter in the mains supply mode or the battery supply mode, the voltage conversion circuit and the three-bridge arm change circuit are all involved in working, namely all devices of the three-bridge arm topology device are all involved in working. When the three-bridge-arm topological device is applied to the battery low-voltage large-current UPS system, the device reuse rate of the system can be improved, the device design redundancy is avoided, and the cost of the battery low-voltage large-current UPS system is further reduced.

The following illustrates an implementation of the above-described diverter switch:

with continued reference to fig. 2, in a three-arm topology, the switch may comprise, for example: a first switch K1, a second switch K2 and a balance component.

The positive pole of the second end of the voltage conversion circuit is connected with the fixed end of the first switch K1, the first selection end of the first switch K1 is connected with the first end of the balance component, the second end of the balance component is connected with the BUS +, the second selection end of the first switch K1 is connected with the positive voltage input end AC _ L, the first end of the second switch K2 is connected with the live wire of the mains supply AC, the second end of the second switch K2 is connected with the positive voltage input end AC _ L, and the negative pole of the second end of the voltage conversion circuit is connected with the BUS-.

In a mains supply mode, a fixed end of the first switch K1 is communicated with a first selection end of the first switch K1, and the second switch K2 is closed; in the battery power mode, the fixed terminal of the first switch K1 is connected to the second selection terminal of the first switch K1, and the second switch K2 is turned off. For example, the first switch K1 may be any selection switch capable of being turned on or off according to a control signal, such as a double-throw relay or a bidirectional electronic switch or a thyristor. The second switch K2 can be any switch capable of being turned on or off according to a control signal, such as a single throw relay, a unidirectional electronic switch, a thyristor, etc.

Above-mentioned balanced components and parts for when the commercial power supply mode, the balanced three bridge arm converting circuit's BUS and the voltage conversion circuit between voltage to avoid the stiff end of first switch K1 and the first selection end intercommunication of first switch K1 in the twinkling of an eye, to the input great electric current of voltage conversion circuit, thereby can realize overcurrent protection to voltage conversion circuit.

With continued reference to fig. 2, in a first possible implementation, the balancing component may be, for example, a varistor RZ.

Fig. 4 is a schematic diagram of a second three-arm topology device provided by the present invention. In a second possible implementation, as shown in fig. 4, the balancing component may be, for example, a negative temperature coefficient thermistor RT.

Fig. 5 is a schematic diagram of a third bridge arm topology device provided by the present invention. As shown in fig. 5, in a third possible implementation manner, the balancing component may be, for example, a third inductor L3.

Fig. 6 is a schematic diagram of a fourth three-bridge-arm topology apparatus provided by the present invention. As shown in fig. 6, in a fourth possible implementation manner, the balancing component may be, for example, a resistor R1. In this implementation, the switch may further include: and a third switch K3.

With continued reference to FIG. 6, the positive terminal of the second terminal of the voltage conversion circuit is coupled to the first terminal of the third switch K3, and the second terminal of the third switch K3 is coupled to BUS +. Fig. 7 is a schematic diagram of a fifth three-arm topology apparatus provided by the present invention. In a fifth possible connection, as shown in fig. 7, the third switch K3 is connected in parallel with the resistor R1.

Referring to the change-over switch shown in fig. 6 or fig. 7, in the commercial power supply mode, when the voltage difference between the bus and the voltage conversion circuit is less than or equal to the preset threshold, the third switch K3 is closed, so that the voltage conversion circuit charges the battery pack. In the battery powered mode, the third switch K3 is open.

Illustratively, the third switch K3 can be any switch capable of being turned on or off according to a control signal, such as a single-throw relay, a unidirectional electronic switch, a thyristor, and the like.

It is to be understood that the second switch K2 and the third switch K3 may be the same switch or different switches. For example, the second switch K2 is a thyristor, the third switch K3 is a unidirectional electronic switch, and the like.

The following takes the structure of the three-arm topology device shown in fig. 6 as an example, and schematically illustrates the states of the switches, the states of the switching tubes, and the current directions of the three-arm topology device in different power supply modes:

the mains supply mode: and controlling the fixed end of the first switch K1 to be communicated with the first selection end of the first switch K1, closing the second switch K2, and controlling the third switch K3 to be closed when the voltage difference value between the BUS + of the three-bridge arm topology device and the voltage conversion circuit of the three-bridge arm topology device is smaller than or equal to a preset threshold value. At this time, the voltage conversion circuit operates in Buck mode.

Fig. 8 is a schematic current diagram of a fourth three-bridge-arm topology device provided by the present invention in the mains power supply mode. As shown in fig. 8, in the first phase of the positive half cycle of the alternating current, the second switching tube Q2 and the fourth switching tube Q4 of the three-leg inverter circuit are controlled to be turned on, and the first switching tube Q1 and the third switching tube Q3 are controlled to be turned off. At this time, the current in the three-arm topology device flows as follows:

1. the live wire of the commercial power alternating-current power supply AC → the first inductor L1 → the second switching tube Q2 → the fourth switching tube Q4 → the zero wire of the commercial power alternating-current power supply AC constitutes an energy storage loop of the inductor L1.

2. BUS + → the positive pole of the voltage conversion circuit → the positive pole of the battery pack → the negative pole of the voltage conversion circuit → BUS-, constituting the energy storage circuit of the battery pack.

Fig. 9 is a current schematic diagram of a fourth three-bridge-arm topology device provided by the present invention in a mains supply mode, as shown in fig. 9, in a second stage of a positive half cycle of the alternating current, the first switching tube Q1 and the fourth switching tube Q4 are controlled to be turned on, and the second switching tube Q2 and the third switching tube Q3 are turned off. At this time, the current in the three-arm topology device flows as follows:

1. the live wire of the commercial power alternating-current power supply AC → the first inductor L1 → the first switching tube Q1 → the direct-current bus capacitor E1 → the fourth switching tube Q4 → the zero line of the commercial power alternating-current power supply AC, and an energy storage loop is formed, wherein the inductor L1 and the commercial power simultaneously store energy for the direct-current bus capacitor E1.

Fig. 10 is a current schematic diagram of a fourth three-bridge-arm topology device provided by the present invention in a mains supply mode, as shown in fig. 10, in a first stage of a negative half cycle of the alternating current, the first switching tube Q1 and the third switching tube Q3 are controlled to be turned on, and the second switching tube Q2 and the fourth switching tube Q4 are controlled to be turned off. At this time, the current in the three-arm topology device flows as follows:

1. the neutral line of the commercial power alternating-current power supply AC → the third switching tube Q3 → the first switching tube Q1 → the first inductor L1 → the live wire of the commercial power alternating-current power supply AC constitute an energy storage loop of the inductor L1.

Fig. 11 is a current schematic diagram of a fourth three-bridge-arm topology device provided by the present invention in a mains supply mode, as shown in fig. 11, in a second stage of a negative half cycle of the alternating current, the second switching tube Q2 and the third switching tube Q3 are controlled to be turned on, and the first switching tube Q1 and the fourth switching tube Q4 are turned off. At this time, the current in the three-arm topology device flows as follows:

1. the neutral line of the commercial power alternating-current power supply AC → the third switching tube Q3 → the direct-current bus capacitor E1 → the second switching tube Q2 → the first inductor L1 → the live wire of the commercial power alternating-current power supply AC, and an energy storage loop is formed, wherein the inductor L1 and the commercial power simultaneously store energy for the direct-current bus capacitor E1.

Battery-powered mode: the fixed end of the first switch K1 is controlled to be in communication with the second selection end of the first switch K1, and the second switch K2 and the third switch K3 are controlled to be off. At this time, the voltage conversion circuit operates in a Boost mode.

Fig. 12 is a schematic current diagram of a fourth three-bridge topology device in the battery power supply mode, as shown in fig. 12, in the first stage of the battery power supply mode, the second switching tube Q2 is controlled to be turned on, and the first switching tube Q1, the third switching tube Q3 and the fourth switching tube Q4 are controlled to be turned off. At this time, the current in the three-arm topology device flows as follows:

the positive pole of the battery pack → the positive pole of the voltage conversion circuit → the first inductor L1 → the second switching tube Q2 → the negative pole of the voltage conversion circuit → the negative pole of the battery pack, which forms the energy storage loop of the first inductor L1.

Fig. 13 is a schematic current diagram of another three-leg topology device provided by the present invention in the battery-powered mode, as shown in fig. 13, in the second stage of the battery-powered mode, the first switch tube Q1 is controlled to be turned on, and the second switch tube Q2, the third switch tube Q3 and the fourth switch tube Q4 are turned off. At this time, the current in the three-arm topology device flows as follows:

the positive electrode of the battery pack → the positive electrode of the voltage conversion circuit → the first inductor L1 → the first switching tube Q1 → the direct current bus capacitor E1 → the negative electrode of the voltage conversion circuit → the negative electrode of the battery pack, and the energy storage loop of the direct current bus capacitor E1 is formed.

It should be understood that, although the current flow of the three-leg topology devices shown in fig. 8 to 12 are schematically illustrated by taking the fourth three-leg topology device shown in fig. 6 as an example. However, it can be understood by those skilled in the art that the current direction, and the states of the switches and the switch tubes are also applicable to the three-arm topology device shown in fig. 7, and the implementation principle is similar, and will not be described again.

In addition, when the three-arm topology device with any structure of fig. 2 to 5 is adopted, the states of the switches, the states of the switching tubes, and the current directions of the three-arm topology device in different modes are as follows:

the mains supply mode: the fixed end of the first switch K1 is controlled to communicate with the first selection end of the first switch K1, and the second switch K2 is closed. At this time, the voltage conversion circuit operates in Buck mode.

In this mode, the states of the switching tubes of the three-bridge arm topology device in the utility power supply mode are the same as the states of the switching tubes of the three-bridge arm topology device shown in fig. 6 in the utility power supply mode. The current direction of the three-bridge-arm topology device is the same as that of the three-bridge-arm topology device shown in fig. 6 in the commercial power supply mode, and specific reference may be made to the descriptions corresponding to fig. 8 to fig. 11, which are not described again.

Battery-powered mode: the fixed end of the first switch K1 is controlled to be connected with the second selection end of the first switch K1, and the second switch K2 is controlled to be disconnected. At this time, the voltage conversion circuit operates in a Boost mode.

In this mode, the state of each switching tube of the three-arm topology device in the battery power supply mode is the same as that of each switching tube of the three-arm topology device in the battery power supply mode shown in fig. 6. The current direction of the three-bridge-arm topology device is the same as that of the three-bridge-arm topology device shown in fig. 6 in the battery power supply mode, and specific reference may be made to the descriptions corresponding to fig. 12 to fig. 13, which are not described again.

Fig. 14 is a schematic diagram of a sixth three-arm topology apparatus provided by the present invention. As shown in fig. 4, in the three-arm topology device, the switch may include, for example: a first switch K1, a second switch K2 and a balance component.

The positive pole of the second end of the voltage conversion circuit is respectively connected with the first end of the first switch K1, the first selection end of the second switch K2 is connected, the second end of the first switch K1 is connected with the first end of the balance component, the second end of the balance component is connected with BUS +, the second selection end of the second switch K2 is connected with the live wire of the mains supply alternating current power supply, the fixed end of the second switch K2 is connected with the positive voltage input end AC _ L, and the negative pole of the second end of the voltage conversion circuit is connected with the BUS-.

In a mains supply mode, the first switch K1 is closed, and the fixed end of the second switch K2 is communicated with the second selection end of the second switch K2; in the battery power mode, the first switch K1 is turned off, and the fixed terminal of the second switch K2 is communicated with the first selection terminal of the second switch K2. For example, the first switch K1 can be any switch capable of being turned on or off according to a control signal, such as a single throw relay, a unidirectional electronic switch, a thyristor, and the like. The second switch K2 can be any selection switch capable of being turned on or off according to a control signal, such as a double-throw relay or a bidirectional electronic switch or a thyristor.

The balance component is used for balancing the voltage between the BUS + of the three-bridge arm conversion circuit and the voltage conversion circuit in a mains supply mode, so that the phenomenon that a fixed end of the first switch K1 is communicated with the first selection end of the first switch K1 instantly, large current is input into the voltage conversion circuit, and overcurrent protection can be achieved on the voltage conversion circuit.

With continued reference to fig. 14, in a sixth possible implementation manner, the balancing component may be, for example, a varistor RZ.

Fig. 15 is a schematic diagram of a seventh three-arm topology apparatus provided by the present invention. In a seventh possible implementation manner, as shown in fig. 15, the balance component may be, for example, a negative temperature coefficient thermistor RT or the like.

Fig. 16 is a schematic diagram of an eighth three-arm topology apparatus provided by the present invention. As shown in fig. 16, in an eighth possible implementation manner, the balancing component may be, for example, a third inductor L3.

When the three-arm topology device with any one of the structures in fig. 14 to 16 is adopted, the states of the switches, the states of the switching tubes, and the current trends in different modes of the three-arm topology device are as follows:

the mains supply mode: the first switch K1 is controlled to be closed, and the fixed end of the second switch K2 is communicated with the second selection end of the second switch K2. At this time, the voltage conversion circuit operates in Buck mode.

Battery-powered mode: the first switch K1 is controlled to be turned off, and the fixed end of the second switch K2 is communicated with the first selection end of the second switch K2. At this time, the voltage conversion circuit operates in a Boost mode.

Fig. 17 is a schematic diagram of a ninth three-arm topology apparatus provided by the present invention. As shown in fig. 17, in a ninth possible implementation manner, the balancing component may be, for example, a resistor R1. In this implementation, the switch may further include: and a third switch K3.

With continued reference to FIG. 17, the positive terminal of the second terminal of the voltage conversion circuit is coupled to the first terminal of the third switch K3, and the second terminal of the third switch K3 is coupled to BUS +. Fig. 18 is a schematic diagram of a tenth three-bridge-arm topology apparatus provided by the present invention. In a tenth possible connection, as shown in fig. 18, the third switch K3 is connected in parallel with the resistor R1.

Referring to the change-over switch shown in fig. 17 or fig. 18, in the commercial power supply mode, when the voltage difference between the bus bar and the voltage conversion circuit is less than or equal to the preset threshold, the third switch K3 is closed, so that the voltage conversion circuit charges the battery pack. In the battery powered mode, the third switch K3 is open.

It should be understood that the same switch may be used for the first switch K1 and the third switch K3, and different switches may be used. For example, the first switch K1 is a thyristor, the third switch K3 is a unidirectional electronic switch, and the like.

When the three-arm topology device with any one of the structures in fig. 17 to 18 is adopted, the states of the switches, the states of the switching tubes, and the current of the three-arm topology device in different modes are as follows:

the mains supply mode: and controlling the first switch K1 to be closed, communicating the fixed end of the second switch K2 with the second selection end of the second switch K2, and controlling the third switch K3 to be closed when the voltage difference value between the BUS of the three-bridge-arm topological device and the voltage conversion circuit of the three-bridge-arm topological device is smaller than or equal to a preset threshold value. At this time, the voltage conversion circuit operates in Buck mode.

Battery-powered mode: the first switch K1 and the third switch K3 are controlled to be turned off, and the fixed end of the second switch K2 is communicated with the first selection end of the second switch K2. At this time, the voltage conversion circuit operates in a Boost mode.

Fig. 19 is a schematic diagram of an eleventh three-bridge arm topology apparatus according to the present invention. As shown in fig. 19, in the three-arm topology device, the switch may include, for example: a first switch K1, a second switch K2, a third switch K3 and a balance component.

The positive pole of the second end of the voltage conversion circuit is connected with the first end of the first switch K1 and the first end of the third switch K3 respectively, the second end of the first switch K1 is connected with the positive voltage input end AC _ L, the first end of the second switch K2 is connected with the live wire of the mains supply AC, the second end of the second switch K2 is connected with the positive voltage input end AC _ L, the second end of the third switch K3 is connected with the first end of the balance component, the second end of the balance component is connected with the BUS +, and the negative pole of the second end of the voltage conversion circuit is connected with the BUS-.

In the mains supply mode, the first switch K1 is open, and the second switch K2 and the third switch K3 are closed; in the battery powered mode, the first switch K1 is closed and the second switch K2 and the third switch K3 are open.

The balance component is used for balancing the voltage between the BUS of the three-bridge arm conversion circuit and the voltage conversion circuit in a mains supply mode, so that the situation that the first switch K3 is closed instantly is avoided, large current is input into the voltage conversion circuit, and overcurrent protection can be achieved for the voltage transfer circuit.

With continued reference to fig. 19, in an eleventh possible implementation, the balancing component may be, for example, a varistor RZ.

Fig. 20 is a schematic diagram of a twelfth three-arm topology apparatus provided in the present invention. As shown in fig. 20, in a twelfth possible implementation manner, the balance component may be, for example, a negative temperature coefficient thermistor RT.

Fig. 21 is a schematic diagram of a thirteenth three-leg topology device provided by the present invention. As shown in fig. 21, in a thirteenth possible implementation manner, the balancing component may be, for example, a third inductor L3.

When the three-arm topology device with any one of the structures in fig. 19 to fig. 21 is adopted, the states of the switches, the states of the switching tubes, and the current trends in different modes are as follows:

the mains supply mode: the first switch K1 is controlled to be open, and the second switch K2 and the third switch K3 are controlled to be closed. At this time, the voltage conversion circuit operates in Buck mode.

Battery-powered mode: the first switch K1 is controlled to be closed, and the second switch K2 and the third switch K3 are controlled to be open. At this time, the voltage conversion circuit operates in a Boost mode.

Fig. 22 is a schematic diagram of a fourteenth three-leg topology device provided by the present invention. As shown in fig. 22, in a fourteenth possible implementation manner, the balancing component may be, for example, a resistor R1. In this implementation, the switch may further include: a fourth switch K4.

With continued reference to FIG. 22, the positive terminal of the second terminal of the voltage conversion circuit is coupled to the first terminal of the fourth switch K4, and the second terminal of the fourth switch is coupled to BUS +. Fig. 23 is a schematic diagram of a fifteenth three-arm topology device provided by the present invention. In a fifteenth possible connection, as shown in fig. 23, a fourth switch K4 is connected in parallel with a resistor R1.

Referring to the switch shown in fig. 22 or 23, in the commercial power supply mode and when the voltage difference between the bus bar and the voltage conversion circuit is less than or equal to the preset threshold, the fourth switch K4 is closed, so that the voltage conversion circuit charges the battery pack. In the battery powered mode, the fourth switch K4 is open.

Illustratively, the fourth switch K4 may be any switch capable of being turned on or off according to a control signal, such as a single-throw relay, a unidirectional electronic switch, a thyristor, and the like.

In the present embodiment, the first switch K1, the second switch K2, the third switch K3 and the fourth switch K4 may be any switches capable of being turned on or off according to a control signal, for example, a single throw relay, a unidirectional electronic switch, a thyristor, etc. It should be understood that the first switch K1, the second switch K2, the third switch K3 and the fourth switch K4 may be the same switch or different switches. For example, the first switch K1 is a thyristor, the second switch K2, the third switch K3 and the fourth switch K4 are single throw relays, and the like, which is not limited in this embodiment.

When the three-arm topology device having any one of the structures in fig. 22 to 23 is adopted, the states of the switches, the states of the switching tubes, and the current in different modes of the three-arm topology device are as follows:

the mains supply mode: and controlling the first switch K1 to be opened, the second switch K2 and the third switch K3 to be closed, and controlling the fourth switch K4 to be closed when the voltage difference value between the BUS of the three-arm topology device and the voltage conversion circuit of the three-arm topology device is smaller than or equal to a preset threshold value. At this time, the voltage conversion circuit operates in Buck mode.

Battery-powered mode: the first switch K1 is controlled to be closed, and the second switch K2, the third switch K3 and the fourth switch K4 are controlled to be open. At this time, the voltage conversion circuit operates in a Boost mode.

It should be understood that the switches shown in fig. 2, fig. 4 to fig. 7, and fig. 14 to fig. 23 are only examples, and since the implementation of the switches is numerous, the switches applied to the three-leg topology device are not listed here. During concrete implementation, a change-over switch can be selected according to actual requirements, so that the voltage conversion circuit is controlled to charge the battery pack in the commercial power supply mode, and the voltage conversion circuit is controlled to discharge the battery pack in the battery power supply mode, and the repeated description is omitted.

In addition, although the three-leg topology circuit is exemplified by being applied to a battery low-voltage large-current UPS system, those skilled in the art can understand that the three-leg topology circuit may also be applied to other UPS systems (e.g., a high-power UPS system), or other systems (e.g., an inverter system) that use different power sources (e.g., commercial power or battery packs) to supply power under different conditions, and details thereof are not repeated.

Further, in the examples of the three-arm topology devices shown in fig. 2, fig. 4 to fig. 7, and fig. 14 to fig. 23, the voltage conversion circuit may be any circuit having a bidirectional voltage conversion function. For example, the voltage conversion circuit shown in fig. 3, etc., but this is not limited thereto.

The utility model also provides an uninterrupted power source system, this system includes: a mains AC power source AC, a load, and, in the foregoing embodiments, a three-arm topology device (e.g., the three-arm topology device illustrated in any of fig. 2, 4-7, and 14-23) is shown. The live wire of the commercial power alternating-current power supply is connected with the positive voltage input end AC _ L of the three-bridge arm topology device, the zero wire of the commercial power alternating-current power supply is connected with the negative voltage input end AC _ N of the three-bridge arm topology device, and the output end of the three-bridge arm topology device is connected with the load.

The utility model provides an uninterrupted power source system can be for battery low pressure heavy current UPS system, perhaps for online medium and low power UPS system etc..

The utility model provides a UPS system, its theory of realization and technological effect are similar with aforementioned three bridge arm topology devices, no longer give unnecessary details here.

It is to be understood that various numbers (e.g., the first switch tube, the second switch tube, the first switch, the second switch, etc.) referred to in the present disclosure are only for convenience of description and should not be used to limit the scope of the embodiments of the present disclosure.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; such modifications and substitutions do not depart from the spirit and scope of the present invention.

Claims

1. A three-leg topology device, comprising: the device comprises a battery pack, a voltage conversion circuit, a change-over switch and a three-bridge arm conversion circuit;

the three-bridge arm conversion circuit includes: the bridge comprises a first bridge arm, a second bridge arm, a third bridge arm, a first inductor, a second inductor, a direct current bus capacitor and a first capacitor;

the first bridge arm comprises a first switching tube and a second switching tube which are connected in series;

the second bridge arm comprises a third switching tube and a fourth switching tube which are connected in series;

the third bridge arm comprises a fifth switching tube and a sixth switching tube which are connected in series;

the first bridge arm, the second bridge arm, the third bridge arm and the direct current bus capacitor are connected in parallel between a positive output end and a negative output end of a bus; the midpoint of the first bridge arm is connected with the first end of the first inductor, and the second end of the first inductor is used as a positive voltage input end of the three-bridge-arm topology device; the midpoint of the second bridge arm is used as a negative voltage input end of the three-bridge-arm topological device; the middle point of the third bridge arm is connected with the first end of the second inductor, the second end of the second inductor is the output end of the three-bridge-arm topological device and is respectively connected with a load and the first end of the first capacitor, and the second end of the first capacitor is connected with the negative voltage input end;

the positive pole of the battery pack is connected with the positive pole of the first end of the voltage conversion circuit, the negative pole of the battery pack is connected with the negative pole of the first end of the voltage conversion circuit, the positive pole of the second end of the voltage conversion circuit is respectively connected with the positive output end of the bus and the positive voltage input end through the change-over switch, the negative pole of the second end of the voltage conversion circuit is connected with the negative output end of the bus, the live wire of the commercial power alternating current power supply is connected with the positive voltage input end through the change-over switch, and the zero line of the commercial power alternating current power supply is connected with the negative voltage input end;

the change-over switch is used for controlling the voltage conversion circuit to charge the battery pack in a mains supply mode; and when in a battery power supply mode, controlling the voltage conversion circuit to discharge the battery pack.

2. The apparatus of claim 1, wherein the switch comprises: the circuit comprises a first switch, a second switch and a balance component;

the positive electrode of the second end of the voltage conversion circuit is connected with the fixed end of the first switch, the first selection end of the first switch is connected with the first end of the balance component, the second end of the balance component is connected with the positive output end of the bus, the second selection end of the first switch is connected with the positive voltage input end, the first end of the second switch is connected with the live wire of the commercial power alternating-current power supply, the second end of the second switch is connected with the positive voltage input end, and the negative electrode of the second end of the voltage conversion circuit is connected with the negative output end of the bus;

the balance component is used for balancing the voltage between the bus and the voltage conversion circuit;

when the mains supply mode is adopted, the fixed end of the first switch is communicated with the first selection end of the first switch, and the second switch is closed; when the battery power supply mode is adopted, the fixed end of the first switch is communicated with the second selection end of the first switch, and the second switch is disconnected.

3. The apparatus of claim 2, wherein the balancing component is a resistor, the switch further comprising: a third switch;

the positive electrode of the second end of the voltage conversion circuit is connected with the first end of the third switch, and the second end of the third switch is connected with the positive output end of the bus; or, the third switch is connected in parallel with the resistor;

when the commercial power supply mode is adopted and the voltage difference value between the bus and the voltage conversion circuit is smaller than or equal to a preset threshold value, the third switch is closed; in the battery powered mode, the third switch is open.

4. The apparatus of claim 1, wherein the switch comprises: the circuit comprises a first switch, a second switch and a balance component;

the positive electrode of the second end of the voltage conversion circuit is connected with the first end of the first switch and the first selection end of the second switch respectively, the second end of the first switch is connected with the first end of the balance component, the second end of the balance component is connected with the positive output end of the bus, the second selection end of the second switch is connected with the live wire of the commercial power alternating-current power supply, the fixed end of the second switch is connected with the positive voltage input end, and the negative electrode of the second end of the voltage conversion circuit is connected with the negative output end of the bus;

when the commercial power supply mode is adopted, the first switch is closed, and the fixed end of the second switch is communicated with the second selection end of the second switch; and when the battery is in the power supply mode, the first switch is disconnected, and the fixed end of the second switch is communicated with the first selection end of the second switch.

5. The apparatus of claim 4, wherein the balancing component is a resistor, the switch further comprising: a third switch;

6. The apparatus of claim 1, wherein the switch comprises: the first switch, the second switch, the third switch and the balance component;

the positive electrode of the second end of the voltage conversion circuit is respectively connected with the first end of the first switch and the first end of the third switch, the second end of the first switch is connected with the positive voltage input end, the first end of the second switch is connected with the live wire of the commercial power alternating-current power supply, the second end of the second switch is connected with the positive voltage input end, the second end of the third switch is connected with the first end of the balance component, the second end of the balance component is connected with the positive output end of the bus, and the negative electrode of the second end of the voltage conversion circuit is connected with the negative output end of the bus;

when the mains supply mode is started, the first switch is closed, and the second switch is opened; in the battery powered mode, the first switch is closed and the second switch and the third switch are open.

7. The apparatus of claim 6, wherein the balancing component is a resistor, the switch further comprising: a fourth switch;

the positive electrode of the second end of the voltage conversion circuit is connected with the first end of the fourth switch, and the second end of the fourth switch is connected with the positive output end of the bus; or, the fourth switch is connected in parallel with the resistor;

when the commercial power supply mode is adopted and the voltage difference value between the bus and the voltage conversion circuit is smaller than or equal to a preset threshold value, the fourth switch is closed; in the battery powered mode, the fourth switch is open.

8. The device of any one of claims 2, 4 and 6, wherein the balancing component is any one of: a piezoresistor, a thermistor with negative temperature coefficient and a third inductor.

9. The apparatus of any of claims 1-7, wherein the voltage conversion circuit comprises: the bridge comprises a fourth bridge arm, a fifth bridge arm, a sixth bridge arm, a seventh bridge arm, a transformer, a third inductor, a second capacitor and a third capacitor;

the fourth bridge arm is connected with the fifth bridge arm in parallel, the sixth bridge arm, the seventh bridge arm and the third capacitor are connected in parallel, the first end of the transformer is connected with the midpoint of the fourth bridge arm, the second end of the transformer is connected with the midpoint of the fifth bridge arm, the third end of the transformer is connected with the midpoint of the fifth bridge arm through the third inductor and the second capacitor, and the fourth end of the transformer is connected with the midpoint of the sixth bridge arm;

10. An uninterruptible power supply system, the system comprising: a mains ac power supply, a load, and a three-bridge arm topology device as claimed in any one of claims 1 to 9;

the live wire of the commercial power alternating-current power supply is connected with the positive voltage input end of the three-bridge arm topology device, the zero wire of the commercial power alternating-current power supply is connected with the negative voltage input end of the three-bridge arm topology device, and the output end of the three-bridge arm topology device is connected with the load.