CN102832688B - Uninterruptible power supply - Google Patents

Abstract

The invention discloses an uninterruptible power supply, which includes a subunit and a switch tube drive module, the subunit includes a first bridge arm formed by connecting a first controllable switch and a second controllable switch, a third controllable switch and a fourth controllable switch The second bridge arm formed by connecting the fifth controllable switch and the sixth controllable switch, the first inductor, the bus capacitor, the second inductor, the second capacitor, the first switch and the second A switch; the uninterruptible power supply also includes a battery; the positive pole of the battery is coupled to the first end of the second switch, the second end of the second switch is coupled to the first end of the first inductance, and the negative pole of the battery is coupled to the negative pole of the bus capacitor; or , the positive pole of the battery is coupled to the positive pole of the bus capacitor, the negative pole of the battery is coupled to the first terminal of the second switch, and the second terminal of the second switch is coupled to the first terminal of the first inductor. By improving the battery connection form, the control algorithm of the two controllable switches in the second bridge arm is simplified when the circuit works in the battery mode.

Description

an uninterruptible power supply

【Technical field】

The invention relates to power electronic devices, in particular to an uninterruptible power supply.

【Background technique】

As shown in Figure 1, it is a circuit diagram of an existing uninterruptible power supply (UPS for short). In the figure, the UPS includes a subunit, and the subunit includes a first controllable switch Q1 and a second controllable switch Q2 connected to form The first bridge arm of the first bridge arm, the second bridge arm formed by connecting the third controllable switch Q3 and the fourth controllable switch Q4, the third bridge arm formed by connecting the fifth controllable switch Q5 and the sixth controllable switch Q6, the first Inductor L1, bus capacitor DC1, second inductor L2, second capacitor C2, first switch S1, and second switch S2; the first end of the first switch S1 is coupled to the mains input, and the second end of the first switch S1 is coupled to The first end of the first inductor L1 is coupled, the second end of the first inductor L1 is coupled to the midpoint of the first bridge arm, and the first bridge arm, the second bridge arm and the third bridge arm are respectively connected across the bus capacitor DC1 Positive and negative, the midpoint of the second bridge arm is coupled to the neutral line N, the midpoint of the third bridge arm is coupled to the first end of the second inductance L2, the second end of the second inductance L2 is coupled to the first end of the second capacitor C2 The second end of the second capacitor C2 is coupled to the neutral line N. The UPS also includes a battery BATTERY, the positive pole of the battery BATTERY is coupled to the first end of the first inductor L1 through the second switch S2, and the negative pole of the battery BATTERY is coupled to the neutral line.

In the above UPS circuit, the first inductor L1, the body diodes of the first controllable switch Q1, the second controllable switch Q2, the third controllable switch Q3 and the body diode of the fourth controllable switch Q4 form a power factor correction (PowerFactor Correction , referred to as PFC) circuit. The third controllable switch Q3, the fourth controllable switch Q4, the fifth controllable switch Q5, the sixth controllable switch Q6, the second inductor L2, and the second capacitor C2 form a full-bridge inverter circuit. After the power factor correction of the PFC circuit, the input current becomes a sine wave with the same phase as the input mains power and has less harmonic content. The PFC circuit also acts as an AC/DC converter to convert the input mains power into the voltage at both ends of the bus capacitor DC1. The full-bridge inverter circuit inverts the DC voltage at both ends of the bus capacitor DC1 into a high-quality sinusoidal voltage for the load. In the circuit, since the second bridge arm composed of the third controllable switch Q3 and the fourth controllable switch Q4 is shared by the PFC circuit and the full-bridge inverter circuit, fewer switching tubes are used in the circuit, and the cost of the circuit is lower . At the same time, since the rectified current of the PFC circuit and the inverted current of the inverter circuit pass through the controllable switch (Q3 or Q4) of the second bridge arm in opposite directions in most cases, most of them can be offset, so the third controllable switch The current flowing through Q3 and the fourth controllable switch Q4 is small, and the power lost thereon is small, so the circuit loss is also small.

However, in order to realize the normal operation of the above circuit, a complex control algorithm is required to generate the driving signals of each controllable switch to control the working state of each controllable switch, especially the third controllable switch Q3 and the fourth controllable switch of the second bridge arm in the circuit. Since the controllable switch Q4 is shared by the PFC circuit and the full-bridge inverter circuit, the driving control algorithm corresponding to the two controllable switches is relatively complicated.

In addition, in addition to the above subunits, the existing UPS also includes a switch tube drive module. As shown in Figure 2, it is the circuit diagram of the switch tube drive module. The switch tube drive module includes a front-end filter module 1, an intermediate isolation coupling module 2, and a back-end drive module 3. The input terminal of the front-end filter module 1 receives the front end of the switch tube drive module. The switching tube drive control signal DRV1 output by the first stage is filtered, the first output terminal A of the front-end filter module 1 is connected to the first input terminal C of the intermediate isolation coupling module 2, the second output terminal B of the front-end filter module 1, That is, the ground terminal is connected to the second input terminal D of the intermediate isolation coupling module 2 . The first output terminal F of the intermediate isolation coupling module 2 is connected to the input terminal I of the back-end drive module 3, the second output terminal E is connected to the positive power line V+ of the back-end drive module 3, and the third output terminal G is connected to the back-end drive module 3 The negative supply line V-. The drive signal output terminal L of the back-end drive module 3 is connected to the control terminal of the switch tube (such as the second controllable switch Q2, the fourth controllable switch Q4 and the sixth controllable switch Q6) located at the lower end of the bridge arm in the UPS subunit, The neutral line M of the back-end drive module 3 is connected to the negative pole of the bus capacitor DC1.

How to improve the switching tube drive module to reduce the device cost of the whole UPS is also the direction of efforts of those skilled in the art.

【Content of invention】

The technical problem to be solved by the present invention is to make up for the deficiencies of the above-mentioned prior art, and propose an uninterruptible power supply, which can relatively simplify the connection between the third controllable switch Q3 and the fourth controllable switch Q4 in the second bridge arm of the circuit. Drive control algorithm.

The further technical problem to be solved by the present invention is to make up for the deficiencies of the above-mentioned prior art, and propose an uninterruptible power supply, which can reduce the device cost of the whole UPS by improving the switch tube drive module.

Technical problem of the present invention is solved by following technical scheme:

An uninterruptible power supply, including a subunit and a switch tube drive module, the subunit includes a first bridge arm formed by connecting a first controllable switch and a second controllable switch, a third controllable switch and a fourth controllable switch The second bridge arm formed by connecting, the third bridge arm formed by connecting the fifth controllable switch and the sixth controllable switch, the first inductor, the bus capacitor, the second inductor, the second capacitor, the first switch and the second switch; The first end of the first switch is coupled to the mains input, the second end of the first switch is coupled to the first end of the first inductor, and the second end of the first inductor is coupled to the first The midpoint of the bridge arm is coupled, the first bridge arm, the second bridge arm and the third bridge arm are respectively connected across the positive pole and the negative pole of the bus capacitor, and the midpoint of the second bridge arm is coupled to the neutral line, so The midpoint of the third bridge arm is coupled to the first end of the second inductance, the second end of the second inductance is coupled to the first end of the second capacitor, and the second end of the second capacitor coupled to the neutral line; characterized in that: the uninterruptible power supply also includes a battery; the positive pole of the battery is coupled to the first end of the second switch, and the second end of the second switch is coupled to the first inductance The first end is coupled, the negative pole of the battery is coupled to the negative pole of the bus capacitor; or, the positive pole of the battery is coupled to the positive pole of the bus capacitor, and the negative pole of the battery is coupled to the first terminal of the second switch coupling, the second end of the second switch is coupled to the first end of the first inductor.

In the preferred technical solution,

The subunit also includes a first capacitor, the first end of the first capacitor is coupled to the positive pole of the battery, and the second end of the first capacitor is coupled to the negative pole of the battery.

In a further preferred technical solution,

The subunit further includes a third inductor, and the midpoint of the second bridge arm is coupled to the neutral line through the third inductor.

The switching tube drive module includes a front-end filter module and a back-end drive module, the first output end of the front-end filter module is connected to the input end of the back-end drive module, and the ground end of the front-end filter module is directly connected to the back-end drive module. The neutral line of the end drive module is connected, and the neutral line of the rear drive module is coupled with the negative pole of the bus capacitor (DC1) in the subunit.

The beneficial effect that the present invention compares with prior art is:

In the uninterruptible power supply of the present invention, by improving the battery connection form, when the circuit works in battery mode, the two controllable switches (Q3, Q4) in the second bridge arm are completely "released" from the PFC circuit , then when the circuit switches from mains mode to battery mode, it is no longer necessary to change the control algorithm of the two controllable switches (Q3, Q4) to avoid burning them. In battery mode, the controllable switches (Q3, Q4) The control algorithm of the mains mode can still be used, and the control algorithm of the controllable switch (Q3, Q4) is no longer the same as the existing one, which includes both the control algorithm in the mains mode and the control algorithm in the battery mode. , but simplified to only include the part of the control algorithm in the mains mode. Furthermore, since the two controllable switches (Q3, Q4) are completely "released" from the PFC circuit in the battery mode, even if the two-part control algorithm is still designed according to the distinction between the mains mode and the battery mode, due to the two The controllable switches (Q3, Q4) only need to be responsible for the work of the inverter circuit, and the corresponding control algorithm of the two controllable switches (Q3, Q4) in the battery mode is also much simplified compared with the control algorithm in the battery mode in the prior art. By designing the control algorithm in two parts, the overall control algorithm can also be simplified. Further, in the uninterruptible power supply of the present invention, the switch tube drive module in the UPS, the ground terminal of the front-end filter module and the neutral line of the rear-end drive module are connected to the common ground, which can save the use of the intermediate isolation coupling module and reduce the components of the entire UPS. cost.

【Description of drawings】

Fig. 1 is the circuit diagram of uninterruptible power supply in the prior art;

Fig. 2 is a circuit diagram of a switching tube drive module in an uninterruptible power supply in the prior art;

Fig. 3 is a circuit diagram of an uninterruptible power supply in Embodiment 1 of the present invention;

Fig. 4a is a diagram of the current flow of the first inductor in the PFC circuit when the energy is stored in the first inductor in the uninterruptible power supply mains mode of the first embodiment of the present invention when the positive half cycle is input and the positive half cycle is output;

Fig. 4b is a current flow diagram when the energy stored in the first inductance in the PFC circuit is transferred to the bus capacitor when the positive half cycle is input and the positive half cycle is output in the uninterruptible power supply mains mode of the first embodiment of the present invention;

Fig. 4c is a current flow diagram when the energy stored in the bus capacitor in the inverter circuit is transferred to the second inductance when the positive half cycle is input and the positive half cycle is output in the mains mode of the uninterruptible power supply in the first embodiment of the present invention;

Fig. 4d is a diagram of the current flow when the energy storage in the second inductance in the inverter circuit is transferred to the second capacitor when the positive half-cycle is input and the positive half-cycle is output in the mains mode of the uninterruptible power supply in Embodiment 1 of the present invention;

Fig. 5a is a diagram of the current flow of the first inductor in the PFC circuit when the energy is stored in the first inductor in the uninterruptible power supply mains mode of the first embodiment of the present invention when the negative half cycle is input and the negative half cycle is output;

Fig. 5b is a current flow diagram when the energy storage of the first inductance in the PFC circuit is transferred to the bus capacitor in the uninterruptible power supply mains mode of the first embodiment of the present invention when the negative half cycle is input and the negative half cycle is output;

Fig. 5c is a diagram of the current flow when the energy stored in the bus capacitor in the inverter circuit is transferred to the second inductor when the negative half-cycle is input and the negative half-cycle is output in the mains mode of the uninterruptible power supply in Embodiment 1 of the present invention;

Fig. 5d is a diagram of the current flow when the energy storage in the second inductor in the inverter circuit is transferred to the second capacitor when the negative half-cycle is input and the negative half-cycle is output under the uninterruptible power supply mains mode in Embodiment 1 of the present invention;

Fig. 6a is the current flow diagram of the first inductor of the PFC circuit in the battery mode of the uninterruptible power supply in the prior art when the energy is stored;

Fig. 6b is a current flow diagram when the first inductance of the PFC circuit is stored in the uninterruptible power supply battery mode and transferred to the bus capacitor;

Fig. 7a is a diagram of the current flow when the first inductor of the PFC circuit is storing energy in the uninterruptible power supply battery mode in Embodiment 1 of the present invention;

Fig. 7b is a diagram of the current flow when the energy stored in the first inductance of the PFC circuit is transferred to the bus capacitor in the uninterruptible power supply battery mode in the first embodiment of the present invention;

Fig. 8 is a circuit diagram of an uninterruptible power supply in Embodiment 2 of the present invention;

Fig. 9a is a diagram of the current flow when the first inductor of the PFC circuit is storing energy in the battery mode of the uninterruptible power supply in the second embodiment of the present invention;

Fig. 9b is a diagram of the current flow when the energy stored in the first inductance of the PFC circuit is transferred to the bus capacitor in the battery mode of the uninterruptible power supply in the second embodiment of the present invention;

Fig. 10 is the circuit diagram of the uninterruptible power supply in the third embodiment of the present invention;

Fig. 11 is the circuit diagram of the uninterruptible power supply in the fourth embodiment of the present invention;

Fig. 12 is the circuit diagram of the uninterruptible power supply in the fifth embodiment of the present invention;

Fig. 13 is the circuit diagram of the uninterruptible power supply in the sixth embodiment of the present invention;

Fig. 14 is the circuit diagram of the uninterruptible power supply in the seventh embodiment of the present invention;

Fig. 15 is a circuit diagram of an uninterruptible power supply in Embodiment 8 of the present invention;

Fig. 16 is a circuit diagram of the uninterruptible power supply in the ninth embodiment of the present invention;

Fig. 17 is a circuit diagram of an uninterruptible power supply in the tenth embodiment of the present invention;

Fig. 18 is a circuit diagram of the switching tube drive module in the uninterruptible power supply in the eleventh embodiment of the present invention.

【Detailed ways】

The present invention will be described in further detail below in combination with specific embodiments and with reference to the accompanying drawings.

Specific implementation mode one

As shown in FIG. 3 , it is a circuit diagram of the uninterruptible power supply in this specific embodiment. The uninterruptible power supply includes a switching tube drive module (not shown in the figure), a subunit 100 and a battery BATTERY. The subunit 100 includes a first bridge arm formed by connecting the first controllable switch Q1 and the second controllable switch Q2, a second bridge arm formed by connecting the third controllable switch Q3 and the fourth controllable switch Q4, and a fifth controllable switch Q3. The third bridge arm formed by connecting the switch Q5 and the sixth controllable switch Q6, the first inductor L1, the bus capacitor DC1, the second inductor L2, the second capacitor C2, the first switch S1 and the second switch S2. In the subunit 100, the first end of the first switch S1 is coupled to the mains input, the second end of the first switch S1 is coupled to the first end of the first inductor L1, and the second end of the first inductor L1 is coupled to the first bridge The midpoint of the arm is coupled, the first bridge arm, the second bridge arm and the third bridge arm are respectively connected across the positive pole and the negative pole of the bus capacitor DC1, the midpoint of the second bridge arm is coupled to the neutral line N, and the midpoint of the third bridge arm The point is coupled to the first terminal of the second inductor L2, the second terminal of the second inductor L2 is coupled to the first terminal of the second capacitor C2, and the second terminal of the second capacitor C2 is coupled to the neutral line N. The connection relationship between the battery BATTERY and the subunit is that the positive pole of the battery BATTERY is coupled to the first terminal of the second switch S2, the second terminal of the second switch S2 is coupled to the first terminal of the first inductor L1, and the negative pole of the battery BATTERY is coupled to the bus bar Negative coupling of capacitor DC1. Compared with the existing UPS circuit, the negative pole of the battery BATTERY is no longer connected to the neutral line, but directly connected to the negative pole of the bus capacitor DC1.

The first controllable switch Q1, the second controllable switch Q2, the third controllable switch Q3, the fourth controllable switch Q4, the fifth controllable switch Q5 and the sixth controllable switch Q6 are controllable switches of the same type, The controllable switch of the same type may be metal oxide semiconductor field effect transistor, insulated gate bipolar transistor, power transistor, turn-off thyristor, MOS (Metal-Oxide-Semiconductor, metal-oxide-semiconductor) controlled thyristor , static induction transistor, static induction thyristor or integrated gate commutation thyristor, etc.

In the above subunit circuit, the first inductor L1, the body diodes of the first controllable switch Q1, the second controllable switch Q2, the third controllable switch Q3 and the body diode of the fourth controllable switch Q4 form a PFC circuit. The third controllable switch Q3, the fourth controllable switch Q4, the fifth controllable switch Q5, the sixth controllable switch Q6, the second inductor L2, and the second capacitor C2 form an inverter circuit. The circuit structures and working principles of the PFC circuit and the inverter circuit are the same as those of the existing UPS, and will not be repeated here.

When the above-mentioned circuit works in the mains mode, the control state of each controllable switch is the same as that of the existing UPS, and only a brief description will be given below.

When the mains input is in the positive half cycle, the circuit output is also in the positive half cycle, then the PFC circuit works in the positive half cycle, and the inverter circuit also works in the positive half cycle, then it needs to be controlled: the first controllable switch Q1 is turned off; the second controllable switch Q1 is turned off; The switch Q2 chops at high frequency according to the pulse width modulation signal generated by the PFC control amount and the carrier; the third controllable switch Q3 is turned off; the fourth controllable switch Q4 is turned on; the fifth controllable switch Q5 is based on the inverter control amount and the carrier wave The generated driving signal is chopped at high frequency, and the sixth controllable switch Q6 and the fifth controllable switch Q5 work in complementarity. In the PFC circuit, the current loop when the first inductor L1 stores energy is shown by the dashed arrow in Figure 4a, and the current loop when the energy stored in the first inductor L1 is transferred to the bus capacitor DC1 is shown by the dashed arrow in Figure 4b; in the inverter circuit The current loop when the energy stored in the bus capacitor DC1 is released to the second inductor L2 is shown by the dashed arrow in Figure 4c, and the current loop when the energy stored in the second inductor L2 is released to the second capacitor C2 is shown by the dashed arrow in Figure 4d.

When the mains input negative half cycle, the circuit output is also negative half cycle, then the PFC circuit works in the negative half cycle, and the inverter circuit also works in the negative half cycle, then it needs to be controlled: the first controllable switch Q1 is generated according to the PFC control amount and carrier wave The pulse width modulation signal is chopped at high frequency; the second controllable switch Q2 is turned off; the third controllable switch Q3 is turned on; the fourth controllable switch Q4 is turned off; the sixth controllable switch Q6 is based on the inverter control amount and the carrier wave The generated driving signal is chopped at high frequency, and the fifth controllable switch Q5 and the sixth controllable switch Q6 work complementary. In the PFC circuit, the current loop when the first inductor L1 stores energy is shown by the dashed arrow in Figure 5a, and the current loop when the energy stored in the first inductor L1 is transferred to the bus capacitor DC1 is shown by the dashed arrow in Figure 5b; in the inverter circuit The current loop when the energy stored in the bus capacitor DC1 is released to the second inductor L2 is shown by the dashed arrow in Figure 5c, and the current loop when the energy stored in the second inductor L2 is released to the second capacitor C2 is shown by the dashed arrow in Figure 5d.

If the above circuit works in battery mode, the work of each controllable switch in the inverter circuit part is still the same as in the inverter circuit in the existing UPS, and the work of each controllable switch in the PFC circuit is the same as that in the existing UPS. It is different in PFC circuit.

FIG. 6 shows the current flow diagram of the PFC circuit in the battery mode in the existing UPS circuit. Fig. 6a is a diagram of the current flow when the first inductor L1 in the PFC circuit stores energy in the conventional UPS in battery mode. At this time, the current flows along the positive pole of the battery BATTERY → the second switch S2 → the first inductor L1 → the second controllable switch Q2 → the fourth controllable switch Q4 → the neutral line N → the negative pole of the battery BATTERY, storing energy for the first inductor L1. Fig. 6b is a current flow diagram when the energy stored in the first inductor L1 in the PFC circuit of the existing UPS is released to the bus capacitor DC1 in the battery mode. At this time, the current flows along the positive pole of the battery BATTERY → the second switch S2 → the first inductor L1 → the first controllable switch Q1 → the bus capacitor DC1 → the fourth controllable switch Q4 → the neutral line N → the negative pole of the battery BATTERY, charging the bus capacitor DC1.

In this specific embodiment, the current flow diagram of the PFC circuit in the battery mode of the UPS circuit is shown in FIG. 7 . Fig. 7a is a diagram of the current flow when the first inductor L1 in the PFC circuit stores energy in the UPS circuit in the battery mode in this specific embodiment. At this time, the current flows along the positive pole of the battery BATTERY → the second switch S2 → the first inductor L1 → the second controllable switch Q2 → the negative pole of the battery BATTERY, storing energy for the first inductor L1. Fig. 7b is a diagram of the current flow when the energy stored in the first inductor L1 in the PFC circuit is released to the bus capacitor DC1 in the battery mode. At this time, the current flows along the positive pole of the battery BATTERY→the second switch S2→the first inductor L1→the first controllable switch Q1→the bus capacitor DC1→the negative pole of the battery BATTERY to charge the bus capacitor DC1.

Comparing the current loops in Fig. 6 and Fig. 7, it can be seen that when the UPS in this specific embodiment is in battery mode, the PFC circuit no longer needs the participation of the two controllable switches (Q3, Q4) in the second bridge arm, The two controllable switches (Q3, Q4) only need to undertake the work tasks in the inverter circuit, so that the driving control algorithms corresponding to the third controllable switch Q3 and the fourth controllable switch Q4 can be relatively simplified. The specific analysis is:

Analyze the reasons why the control algorithms of the third controllable switch Q3 and the fourth controllable switch Q4 in the existing UPS circuit are very complicated. On the one hand, because the second bridge composed of the third controllable switch Q3 and the fourth controllable switch Q4 The arm is shared by the PFC circuit and the full-bridge inverter circuit, so that the two controllable switches "take on" two roles. When the input is the positive half cycle of the mains or directly powered by the battery, and the output is the positive half cycle of the inverter, it is necessary The fourth controllable switch Q4 takes into account both the work in the PFC circuit and the inverter circuit; when the input is the negative half-cycle of the mains or directly powered by the battery, and the output is the negative half-cycle of the inverter, the third controllable switch Q3 is required at the same time Taking into account the work of the PFC circuit and the inverter circuit. Therefore, due to the "dual identities" of the third controllable switch Q3 and the fourth controllable switch Q4 "serving" two roles, the content of the control algorithm corresponding to the two controllable switches (Q3, Q4) is compared to other controllable switches (Q1, Q4). Q2, Q3 and Q4) are more complicated. On the other hand, when it is necessary to switch the circuit from the commercial power mode to the battery mode, in order to avoid the burning of the third controllable switch Q3 and the fourth controllable switch Q4 due to the long-term conduction, it is necessary to control the third controllable switch The corresponding driving control algorithm of Q3 and the fourth controllable switch Q4 is reset, that is, the control algorithm of the third controllable switch Q3 and the fourth controllable switch Q4 includes two parts, one part corresponds to the work in the mains mode, and the other A part corresponds to the work in battery mode. Therefore, the content of the control algorithms of the third controllable switch Q3 and the fourth controllable switch Q4 is relatively more than that of other controllable switches. To sum up, the control algorithms of the third controllable switch Q3 and the fourth controllable switch Q4 are complicated, and they contain two parts, so the control algorithms are relatively complicated. Through the change of the battery connection form in this specific embodiment, when the UPS is in the battery mode, the PFC circuit no longer needs the participation of the two controllable switches (Q3, Q4) in the second bridge arm. The switches (Q3, Q4) only need to undertake the work tasks in the inverter circuit, so the complexity of the control algorithm is relatively reduced. At the same time, because the PFC circuit does not involve the third controllable switch Q3 and the fourth controllable switch Q4 in the battery mode, it is not necessary to avoid the third controllable switch Q3 and the fourth controllable switch Q4 from being turned on and burning for a long time in the battery mode. And reset the control algorithm, the control algorithm in the mains mode can still be used in the battery mode, and the content of the control algorithm is relatively reduced. That is, by changing the battery connection form, the drive control algorithms corresponding to the third controllable switch Q3 and the fourth controllable switch Q4 are relatively simplified in terms of algorithm complexity and algorithm content.

Specific implementation mode two

As shown in Figure 8, the difference between this specific embodiment and the first embodiment is that: the positive pole of the battery BATTERY is coupled to the positive pole of the bus capacitor DC1, the negative pole of the battery BATTERY is coupled to the first end of the second switch S2, and the second switch The second end of S2 is coupled to the first end of the first inductor L1. This form of battery connection can also achieve the purpose of simplifying the drive control algorithms corresponding to the third controllable switch Q3 and the fourth controllable switch Q4.

As shown in FIG. 8 , it is a circuit diagram of an uninterruptible power supply in this specific embodiment, including a subunit 100 and a battery BATTERY. The subunit 100 includes a first bridge arm formed by connecting the first controllable switch Q1 and the second controllable switch Q2, a second bridge arm formed by connecting the third controllable switch Q3 and the fourth controllable switch Q4, and a fifth controllable switch Q3. The third bridge arm formed by connecting the switch Q5 and the sixth controllable switch Q6, the first inductor L1, the bus capacitor DC1, the second inductor L2, the second capacitor C2, the first switch S1 and the second switch S2. In the subunit 100, the first end of the first switch S1 is coupled to the mains input, the second end of the first switch S1 is coupled to the first end of the first inductor L1, and the second end of the first inductor L1 is coupled to the first bridge The midpoint of the arm is coupled, the first bridge arm, the second bridge arm and the third bridge arm are respectively connected across the positive pole and the negative pole of the bus capacitor DC1, the midpoint of the second bridge arm is coupled to the neutral line N, and the midpoint of the third bridge arm The point is coupled to the first terminal of the second inductor L2, the second terminal of the second inductor L2 is coupled to the first terminal of the second capacitor C2, and the second terminal of the second capacitor C2 is coupled to the neutral line N. The connection relationship between the battery BATTERY and the subunit is that the positive pole of the battery BATTERY is coupled to the positive pole of the bus capacitor DC1, the negative pole of the battery BATTERY is coupled to the first terminal of the second switch S2, and the second terminal of the second switch S2 is coupled to the first inductor L1 The first end coupling.

In this specific embodiment, the current flow diagram of the PFC circuit in the battery mode of the UPS circuit is shown in FIG. 9 . Fig. 9a is a diagram of the current flow when the first inductor L1 in the PFC circuit stores energy in the UPS circuit in the battery mode in this specific embodiment. At this time, the current flows along the positive pole of the battery BATTERY → the first controllable switch Q1 → the first inductor L1 → the second switch S2 → the negative pole of the battery BATTERY, storing energy for the first → inductor L1. FIG. 9 b is a diagram of the current flow when the energy stored in the first inductor L1 in the PFC circuit is released to the bus capacitor DC1 in the battery mode. At this time, the current flows along the positive pole of the battery BATTERY→the bus capacitor DC1→the second controllable switch Q2→the first inductor L1→the second switch S2→the negative pole of the battery BATTERY to charge the bus capacitor DC1.

From the current flow diagram shown in Figure 9, it can be seen that in this battery connection mode, when the UPS is in battery mode, the PFC circuit also does not need the participation of the two controllable switches (Q3, Q4) in the second bridge arm. The two controllable switches (Q3, Q4) only need to undertake the work tasks in the inverter circuit, which can also be the same as in the first embodiment, relatively simplifying the driving corresponding to the third controllable switch Q3 and the fourth controllable switch Q4 control algorithm.

Specific implementation mode three

As shown in Figure 10, the difference between this specific embodiment and the first embodiment is that the subunit also includes a first capacitor C1, the first end of the first capacitor C1 is coupled to the positive pole of the battery BATTERY, and the second end is coupled to the positive pole of the battery BATTERY negative coupling.

In this specific embodiment, connecting the first capacitor C1 in the above manner can effectively avoid total harmonic distortion (Total Harmonic Distortion of Current, THDi for short) of the UPS input current caused by improper placement of the capacitor. This is because the usual capacitance connection method is the first connection method: connect the first end of the first capacitor C1 to the first end of the first inductor L1, and connect the second end to the neutral line N; or make a slight improvement to obtain the second In this connection method, the first end of the first capacitor C1 is connected to the first end of the first inductor L1, and the second end is connected to the negative pole of the bus capacitor. In the above two common connection methods, improper capacitor positions are likely to cause deterioration of the THDi index of the UPS.

After connecting the first capacitor C1 according to the first connection method, in battery mode, it is easy to form a loop at the moment when the third controllable switch Q3 is turned on. The loop is: positive pole of bus capacitor DC1 → third controllable switch Q3 → neutral line N → the first capacitor C1 → the second switch S2 → the positive pole of the battery BATTERY → the negative pole of the battery BATTERY → the negative pole of the bus capacitor DC1.

After connecting the first capacitor C1 according to the first connection method, in the battery mode, it is easy to form a loop at the moment when the fourth controllable switch Q4 is turned on. The loop is: positive pole of the battery BATTERY→second switch S2→first capacitor C1 →Neutral line N→Fourth controllable switch Q4→Battery BATTERY negative pole.

After connecting the first → capacitor C1 according to the second connection method, in the mains mode, when the mains input crosses zero from the positive half cycle to the negative half cycle, it is easy to form a loop at the moment when the third controllable switch Q3 is turned on. The loop is : Mains input terminal → first capacitor C1 → negative pole of bus capacitor DC1 → positive pole of bus capacitor DC1 → third controllable switch Q3 → neutral line N.

After connecting the first capacitor C1 according to the second connection method, in the mains mode, when the mains input crosses zero from the negative half cycle to the positive half cycle, it is easy to form a loop at the moment when the fourth controllable switch Q4 is turned on. The loop is: neutral line N→fourth controllable switch Q4→first capacitor C1→mains input terminal. At the same time, it is also easy to form a loop when the second controllable switch Q2 is turned on at this time, and the loop is: first capacitor C1→first inductor L1→second controllable switch Q2→first capacitor C1.

A current is formed in the circuit formed under the above circumstances, and the formed current causes the waveform of the input current of the UPS to be distorted, and causes the THDi index of the UPS to deteriorate. However, after the first capacitor C1 is connected according to the method in this specific embodiment, the connection of the first capacitor C1 cannot form the above-mentioned loop, so it is possible to avoid the deterioration of the THDi index of the UPS due to the formation of current. Although the improved connection of the first capacitor C1 in this specific embodiment has little difference from the usual connection, it can overcome the technical bias of those skilled in the art.

Specific implementation mode four

As shown in Figure 11, the difference between this specific embodiment and the second embodiment is that the subunit also includes a first capacitor C1, the first end of the first capacitor C1 is coupled to the positive pole of the battery BATTERY, and the second end is coupled to the positive pole of the battery BATTERY negative coupling. On the basis of the second embodiment of the battery connection, the first capacitor C1 is connected in the above-mentioned manner, which can also prevent the THDi index of the UPS from deteriorating due to improper connection of the first capacitor C1 to form a loop and form a current.

Specific implementation mode five

As shown in FIG. 12 , the difference between this specific embodiment and the first embodiment is that the subunit further includes a third inductor L3, and the midpoint of the second bridge arm is coupled to the neutral line N through the third inductor L3. By adding the third inductor L3, the coupling between the input part and the output part of the UPS can be reduced.

Specific implementation method six

As shown in FIG. 13 , the difference between this specific embodiment and the second embodiment is that the subunit further includes a third inductor L3, and the midpoint of the second bridge arm is coupled to the neutral line N through the third inductor L3. By adding the third inductor L3, the coupling between the input part and the output part of the UPS can be reduced.

Specific implementation mode seven

As an example, as shown in FIG. 14 , the difference between this embodiment and Embodiment 1 is that the subunit further includes a third switch S3, the positive pole of the battery BATTERY is coupled to the first end of the second switch S2, and the second The second terminal of the second switch S2 is coupled to the first terminal of the first inductor L1, and the negative pole of the battery BATTERY is coupled to the negative pole of the bus capacitor DC1 through the third switch S3.

Embodiment 8

As an example, as shown in FIG. 15 , the difference between this specific embodiment and the second embodiment is that the subunit further includes a third switch S3, and the positive pole of the battery BATTERY is coupled to the positive pole of the bus capacitor DC1 through the third switch S3 , the negative pole of the battery BATTERY is coupled to the first terminal of the second switch S2, and the second terminal of the second switch S2 is coupled to the first terminal of the first inductor L1.

Specific implementation mode nine

As shown in FIG. 16 , the difference between this specific embodiment and the first embodiment is that it includes three subunits, namely a first subunit 100 , a second subunit 200 and a third subunit 300 . The structure of each subunit is the same as the subunit in the first embodiment. Wherein, the positive electrode of the battery BATTERY is respectively coupled to the first end of the second switch S2 in the first subunit 100, the second switch S12 in the second subunit 200, and the second switch S22 in the third subunit 300, and the battery The negative pole of BATTERY is respectively coupled to the negative poles of the bus capacitor DC1 in the first subunit 100 , the bus capacitor DC11 in the second subunit 200 , and the bus capacitor DC21 in the third subunit 300 . The UPS in this specific embodiment is the parallel connection of the three UPSs in the first embodiment, realizing the application of three sub-units paralleling and sharing one battery BATTERY, reducing the system cost and obtaining three times the output power at the same time.

Specific implementation ten

As shown in FIG. 17 , the difference between this specific embodiment and the first embodiment is that it includes three subunits, namely a first subunit 100 , a second subunit 200 and a third subunit 300 . The structure of each subunit is the same as the subunit in the second embodiment. Wherein, the positive pole of the battery BATTERY is coupled with the positive poles of the bus capacitor DC1 in the first subunit 100, the bus capacitor DC11 in the second subunit 200, and the bus capacitor DC21 in the third subunit 300 respectively, and the negative pole of the battery BATTERY is coupled with the bus capacitor DC11 in the second subunit 200. First terminals of the second switch S2 in a subunit 100 , the second switch S12 in the second subunit 200 , and the second switch S22 in the third subunit 300 are respectively coupled. The UPS in this specific embodiment is the parallel connection of the three UPSs in the second embodiment, realizing the application of three sub-units paralleling and sharing one battery BATTERY, reducing the system cost and obtaining three times the output power at the same time.

Specific Implementation Mode Eleven

The UPS in this specific embodiment is improved for the switch tube drive module. As shown in FIG. 18 , it is a circuit diagram of the switching tube driving module in the UPS in this specific embodiment. The switch tube drive module includes a front-end filter module 1 and a back-end drive module 3, the first output terminal A of the front-end filter module 1 is connected to the input terminal I of the back-end drive module 3, and the second output terminal B of the front-end filter module 1, that is, The ground terminal is directly connected to the neutral line M of the terminal drive module 3 and then connected to the negative pole of the bus capacitor DC1 in the UPS subunit. That is, the ground terminal of the front-end filter module 1 is connected to the neutral line M of the back-end drive module 3 (the negative pole of the common bus capacitor DC1 is used as the ground terminal), so the switching transistor drive module in this specific embodiment is compared to the existing The switching tube drive module in the technology can save the use of the intermediate isolation coupling module and reduce the device cost of the whole UPS. Using three switch tube drive modules in this specific embodiment to respectively drive the switch tubes located at the lower end of the bridge arm in the UPS subunit, that is, the second controllable switch Q2, the fourth controllable switch Q4 and the sixth controllable switch Q6, can The use of three isolation coupling modules is omitted to achieve low cost.

The above content is a further detailed description of the present invention in conjunction with specific preferred embodiments, and it cannot be assumed that the specific implementation of the present invention is limited to these descriptions. For those of ordinary skill in the technical field to which the present invention belongs, several substitutions or obvious modifications can be made without departing from the concept of the present invention, and the performance or application is the same, all should be considered as belonging to the protection scope of the present invention.

Claims (8)

1. An uninterruptible power supply, comprising a subunit and a switch tube drive module, said subunit comprising a first bridge arm formed by connecting a first controllable switch (Q1) and a second controllable switch (Q2), and a third controllable switch (Q2) The second bridge arm formed by connecting the control switch (Q3) and the fourth control switch (Q4), the third bridge arm formed by connecting the fifth control switch (Q5) and the sixth control switch (Q6), and the first inductor (L1), bus capacitor (DC1), second inductor (L2), second capacitor (C2), first switch (S1) and second switch (S2); the first end of the first switch (S1) Coupled with the mains input, the second end of the first switch (S1) is coupled with the first end of the first inductor (L1), the second end of the first inductor (L1) is coupled with the first The midpoint of the bridge arm is coupled, the first bridge arm, the second bridge arm and the third bridge arm are respectively connected across the positive pole and the negative pole of the bus capacitor (DC1), and the midpoint of the second bridge arm is coupled to Neutral line (N), the midpoint of the third bridge arm is coupled to the first end of the second inductance (L2), and the second end of the second inductance (L2) is coupled to the second capacitor (C2) The first end of the second capacitor (C2) is coupled to the neutral line (N); it is characterized in that: the uninterruptible power supply also includes a battery; The anode of the battery is coupled to the first terminal of the second switch (S2), the second terminal of the second switch (S2) is coupled to the first terminal of the first inductor (L1), and the battery The negative pole of is coupled with the negative pole of the bus capacitor (DC1); or, The positive pole of the battery is coupled to the positive pole of the bus capacitor (DC1), the negative pole of the battery is coupled to the first terminal of the second switch (S2), and the second terminal of the second switch (S2) is coupled to the The first end of the first inductor (L1) is coupled; The subunit also includes a first capacitor (C1), the first terminal of the first capacitor (C1) is directly connected to the positive pole of the battery, and the second terminal is directly connected to the negative pole of the battery. 2. The uninterruptible power supply according to claim 1, characterized in that: the subunit further comprises a third inductor (L3), and the midpoint of the second bridge arm is coupled to Midline (N). 3. The uninterruptible power supply according to claim 1, characterized in that: the subunit further comprises a third switch (S3), when the positive pole of the battery is coupled to the first end of the second switch (S2) , when the second end of the second switch (S2) is coupled to the first end of the first inductor (L1), The negative pole of the battery is coupled to the negative pole of the bus capacitor (DC1) through the third switch (S3). 4. The uninterruptible power supply according to claim 1, characterized in that: the subunit further comprises a third switch (S3), when the negative pole of the battery is coupled with the first end of the second switch (S2) , when the second end of the second switch (S2) is coupled to the first end of the first inductor (L1), The positive pole of the battery is coupled to the positive pole of the bus capacitor (DC1) through the third switch (S3). 5. The uninterruptible power supply according to claim 1, characterized in that: the first controllable switch (Q1), the second controllable switch (Q2), the third controllable switch (Q3), the fourth controllable switch The switch (Q4), the fifth controllable switch (Q5) and the sixth controllable switch (Q6) are controllable switches of the same type, and the controllable switches of the same type are metal oxide semiconductor field effect transistors, insulated gate dual Pole transistors, power transistors, turn-off thyristors, MOS-controlled thyristors, static induction transistors, static induction thyristors or integrated gate commutated thyristors. 6. The uninterruptible power supply according to claim 1, characterized in that: the uninterruptible power supply comprises at least two subunits, the positive pole of the battery is connected to the first switch (S2) of the second switch (S2) of each subunit. The terminals are respectively coupled, and the negative poles of the battery are respectively coupled with the negative poles of the bus capacitance (DC1) of each subunit. 7. The uninterruptible power supply according to claim 1, characterized in that: the uninterruptible power supply comprises at least two subunits, and the positive pole of the battery is coupled with the positive pole of the bus capacitor (DC1) of each subunit respectively , the negative pole of the battery is respectively coupled to the first end of the second switch (S2) of each subunit. 8. The uninterruptible power supply according to claim 1, characterized in that: the switch tube drive module includes a front-end filter module and a back-end drive module, and the first output terminal of the front-end filter module is connected to the back-end drive module The ground terminal of the front-end filter module is directly connected to the neutral line of the rear-end drive module, and the neutral line of the rear-end drive module is coupled to the negative pole of the bus capacitor (DC1) in the sub-unit.