CN208028641U - Power-supply system with DC bus defencive function - Google Patents
Power-supply system with DC bus defencive function Download PDFInfo
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- CN208028641U CN208028641U CN201820232709.8U CN201820232709U CN208028641U CN 208028641 U CN208028641 U CN 208028641U CN 201820232709 U CN201820232709 U CN 201820232709U CN 208028641 U CN208028641 U CN 208028641U
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Abstract
The utility model is related to the power-supply systems with DC bus defencive function; including the first accumulator group and the first DC bus being attached thereto, the first charger; second accumulator group and the second DC bus being attached thereto, the second charger, the bi-directional DC-DC converter being connect respectively with the first accumulator group and the second accumulator group；The system monitor being connected respectively with the first charger, the second charger and bi-directional DC-DC converter；System monitor is used to send conversion voltage to bi-directional DC-DC converter；Bi-directional DC-DC converter is used to receive the second terminal voltage of conversion voltage and the first terminal voltage and the second accumulator group for detecting the first accumulator group, and is opened or closed according to conversion voltage and the relationship of the first terminal voltage and the second terminal voltage.The utility model reliability is high, and control mode is flexible, realizes simple.
Description
Technical Field
The utility model relates to a power supply system field, more specifically say, relate to a power supply system with direct current generating line protect function.
Background
The direct-current operation power supply system in the power system mainly has the advantages that power is supplied to system equipment through a direct-current bus, and when an alternating-current power grid is normal, the alternating-current power grid supplies electric energy to the direct-current bus through a charger; when the AC power grid has power failure, the storage battery pack in the DC operation power supply system provides electric energy for the DC bus. And system equipment on the direct current bus is important equipment and is used for ensuring the normal operation of the power system. In order to improve the power supply reliability of a direct current system, some direct current systems are provided with two sets of chargers, two sets of storage batteries and two sections of direct current buses, as shown in fig. 4, the two sets of storage batteries are mutually standby through a bus tie switch K5, but when an alternating current power grid power failure fault and a set of storage battery fault occur simultaneously, as the bus tie switch K5 needs a professional to manually switch on, before the bus tie switch K5 is closed, the direct current bus with the fault of the storage battery pack is inevitably powered off, so that equipment on the direct current bus stops working, and the normal operation of the power system is influenced. The relay protection equipment on the direct current bus stops running, and the catastrophic accidents of the whole transformer substation are possibly caused. Therefore, how to effectively prevent the loss of power of the dc bus is one of important indicators for determining whether the dc operating power supply system is reliable.
SUMMERY OF THE UTILITY MODEL
The to-be-solved technical problem of the utility model lies in, to the above-mentioned defect of prior art, a electrical power generating system with direct current generating line protect function is provided.
The utility model provides a technical scheme that its technical problem adopted is: constructing a power supply system with a direct current bus protection function; the device comprises a first storage battery pack, a first direct current bus and a first charger which are connected with the first storage battery pack, a second direct current bus and a second charger which are connected with the second storage battery pack, and further comprises:
a bidirectional DC-DC converter connected to the first battery pack and the second battery pack, respectively;
the system monitor is respectively connected with the first charger, the second charger and the bidirectional DC-DC converter;
wherein the system monitor is to send a converted voltage to the bidirectional DC-DC converter;
the bidirectional DC-DC converter is used for receiving the conversion voltage, detecting a first end voltage of the first storage battery pack and a second end voltage of the second storage battery pack, and switching on or switching off according to the relation between the conversion voltage and the first end voltage and the second end voltage.
Preferably, the bidirectional DC-DC converter includes a first interface and a second interface, the first interface is connected with the first battery pack, and the second interface is connected with the second battery pack.
Preferably, the bidirectional DC-DC converter comprises a detection circuit connected to the first interface for detecting the first terminal voltage and/or to the second interface for detecting the second terminal voltage.
Preferably, the bidirectional DC-DC converter comprises a control unit,
the control unit is connected with the detection circuit and the system monitor and used for receiving and comparing the first end voltage, the second end voltage and the conversion voltage so as to control the first interface and/or the second interface to be in an input, output or locking state.
Preferably, the bidirectional DC-DC converter includes an isolation circuit for isolating the first secondary battery pack and the second secondary battery pack.
Preferably, the power supply system of the present invention further includes a first switch and a second switch, wherein the first switch is disposed between the first storage battery pack and the first dc bus, and is used for controlling connection or disconnection between the first storage battery pack and the first dc bus; the second switch is arranged between the second storage battery pack and the second direct current bus and used for controlling the connection or disconnection of the second storage battery pack and the second direct current bus.
Preferably, the power supply system of the present invention further includes a third switch and a fourth switch, wherein the third switch is disposed between the first charger and the first dc bus, and is used for controlling the connection or disconnection between the first charger and the first dc bus; the fourth switch is arranged between the second charger and the second direct-current bus and used for controlling the connection or disconnection of the second charger and the second direct-current bus.
Preferably, the power supply system of the present invention further includes a fifth switch, wherein the fifth switch is disposed between the first dc bus and the second dc bus, and is used for controlling the connection or disconnection between the first dc bus and the second dc bus.
The utility model discloses still construct a direct current generating line protection method, include
S1, detecting and acquiring a first end voltage and a second end voltage corresponding to the first storage battery pack and the second storage battery pack by the bidirectional DC-DC converter;
s2, the bidirectional DC-DC converter comparing the first terminal voltage with a first converted voltage of the bidirectional DC-DC converter and the second terminal voltage with a second converted voltage of the bidirectional DC-DC converter, respectively, performing step S21 if the first terminal voltage is less than or equal to the first converted voltage, and performing step S22 if the second terminal voltage is less than or equal to the second converted voltage;
s21, the bidirectional DC-DC converter controls the second storage battery pack to be communicated with a first direct current bus and supplies power to the first direct current bus;
and S22, the bidirectional DC-DC converter controls the first storage battery pack to be communicated with a second direct current bus and supplies power to the second direct current bus.
Preferably, in step S21, the controlling the second battery pack to communicate with the first DC bus by the bidirectional DC-DC converter includes: the bidirectional DC-DC converter sets a first interface of the bidirectional DC-DC converter to be in an output state and sets a second interface of the bidirectional DC-DC converter to be in an input state;
in step S22, the bidirectional DC-DC converter controlling the first battery pack to communicate with the second DC bus includes: the bidirectional DC-DC converter sets the second interface to be in an output state and sets the first interface to be in an input state.
Preferably, the step S21 further includes: if the second end voltage is less than or equal to the lowest working voltage of the second storage battery pack, the bidirectional DC-DC converter controls the second storage battery pack to be disconnected from the first DC bus and stops supplying power to the first DC bus;
the step S22 further includes: and if the voltage of the first end is less than or equal to the lowest working voltage of the first storage battery pack, the bidirectional DC-DC converter controls the first storage battery pack to be disconnected from the second direct-current bus and stops supplying power to the second direct-current bus.
Preferably, in step S21, the bidirectional DC-DC converter controlling the second battery pack to be disconnected from the first DC bus includes: the bidirectional DC-DC converter sets the first interface and the second interface to be in a locking state;
in step S22, the bidirectional DC-DC converter controlling the first battery pack to be disconnected from the second DC bus includes: the bidirectional DC-DC converter sets the first interface and the second interface to a locked state.
Implement the utility model discloses a power supply system and direct current generating line protection method with direct current generating line protect function has following beneficial effect: the direct current bus has high power supply reliability, so that the two storage battery packs can automatically realize mutual backup, and the direct current bus of the system can not lose power as long as one group of storage batteries is normal. The control mode is flexible and reliable, the realization is simple, and the transformation and the upgrade can be carried out on the existing direct current power supply system.
Drawings
The invention will be further explained with reference to the drawings and examples, wherein:
fig. 1 is a logic block diagram of an embodiment of a power supply system with dc bus protection of the present invention;
fig. 2 is a flowchart of the procedure of the first embodiment of the dc bus protection method of the present invention;
fig. 3 is a flowchart of the procedure of the second embodiment of the dc bus protection method of the present invention;
fig. 4 is a logic block diagram of a conventional dual battery power supply system.
Detailed Description
In order to clearly understand the technical features, objects, and effects of the present invention, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
As shown in fig. 1, in an embodiment of the power supply system with dc bus protection function of the present invention, the power supply system includes a first storage battery set 301, a first dc bus 101 connected to the first storage battery set, a first charger 501, a second storage battery set 302, a second dc bus 102 connected to the second storage battery set, and a second charger 502, and further includes: bidirectional DC-DC converter 20 connected to first battery pack 301 and second battery pack 302, respectively; the system monitor 40 is respectively connected with the first charger 501, the second charger 502 and the bidirectional DC-DC converter 20; wherein the system monitor 40 is configured to send the converted voltage to the bidirectional DC-DC converter 20; the bidirectional DC-DC converter 20 is configured to receive the converted voltage, and is configured to detect a first terminal voltage of the first battery pack and a second terminal voltage of the second battery pack, and turn on or off according to a relationship between the converted voltage and the first terminal voltage and the second terminal voltage, so as to connect or disconnect the first battery pack 301 and the second DC bus 102 or connect or disconnect the second battery pack 302 and the first DC bus 101.
Specifically, the power supply system herein refers to a dc power supply system, which includes two sets of dc buses (i.e., a first dc bus 101 and a second dc bus 102), and two battery packs (i.e., a first battery pack 301 and a second battery pack 302), where the first battery pack 301 is connected to the first dc bus 101 in the power supply system, the second battery pack 302 is connected to the second dc bus 102, and there are a first charger 501 and a second charger 502 that are respectively and correspondingly connected to the first dc bus 101 and the second dc bus 102. The first charger 501 converts ac power into dc power to supply power to the first dc bus 101, and supplements power to the first battery pack 301 through the first dc bus 101, where the output voltage of the first charger 501 may be the float voltage of the first battery pack 301. The second charger 502 converts ac power into dc power to supply power to the second dc bus 102 and charges the second battery pack 302 through the second dc bus 102, where the output voltage of the second charger 502 may be the float voltage of the second battery pack 302.
The system monitor 40 is communicatively connected to the first charger 501, the second charger 502 and the bidirectional DC-DC converter 20, and can monitor the operating status of the entire power system. The system monitor 40 may set the lowest operating voltage of each DC bus, the lowest operating voltage of each battery pack, and the converted voltage of the bidirectional DC-DC converter 20 according to the settings of various components of the power supply system, such as the voltage level of the power supply system, the voltage level of each battery pack, the number of batteries in each battery pack, and the like, and issue the set voltages to the bidirectional DC-DC converter 20. In addition, the communication connection between the bidirectional DC-DC converter 20 and the system monitor 40 may be in an RS485 or CAN manner. The communication connection between each group of chargers and the system monitor 40 CAN also adopt an RS485 or CAN mode.
Further, bidirectional DC-DC converter 20 includes a first interface connected to first battery pack 301, and a second interface connected to second battery pack 302. The input-output characteristics of both interfaces can be set by the bidirectional DC-DC converter 20.
Further, bidirectional DC-DC converter 20 may further include an isolation circuit for isolating first battery pack 301 from second battery pack 302, so as to realize the electrical isolation characteristic of first battery pack 301 from second battery pack 302. When the power supply system is normal, the bidirectional DC-DC converter 20 is in a hot standby state with no output, in which the first interface and the second interface are both in a locked state.
Further, the bidirectional DC-DC converter 20 comprises a detection circuit connected to the first interface for detecting the first terminal voltage and/or to the second interface for detecting the second terminal voltage. It can be understood that, a detection circuit is arranged inside the bidirectional DC-DC converter 20, and is used for detecting and acquiring the voltage of the first interface and the voltage of the second interface in real time, which is equivalent to acquiring the corresponding first terminal voltage and second terminal voltage of the first battery pack 301 and the second battery pack 302 to control the operating state thereof.
Further, the bidirectional DC-DC converter 20 includes a control unit, which is connected to the detection circuit and the system monitor 40, and is configured to receive and compare the first terminal voltage, the second terminal voltage, and the converted voltage to control the first interface and/or the second interface to be in an input, output, or latch state. It is understood that the bidirectional DC-DC converter 20 receives and compares the first terminal voltage, the second terminal voltage and the converted voltage through an internal control unit, where the converted voltage may include a first converted voltage and a second converted voltage, which are respectively compared with the first terminal voltage and the second terminal voltage, and controls the first interface to be in an input, output or latch state and the second interface to be in an input, output or latch state according to the comparison result.
During normal operation, the system monitoring 40 preset parameters required for the operation of the bidirectional DC-DC converter 20 include: the lowest operating voltage of the first battery pack 301 is Ubmin1, the lowest operating voltage of the first DC bus 101 is Umin1, and the first conversion voltage of the bidirectional DC-DC converter 20 is Vset1, where the first conversion voltage Vset1 is greater than or equal to the lowest operating voltage Umin1 of the first DC bus 101; the lowest operating voltage of second battery pack 302 is Ubmin2, the lowest operating voltage of second DC bus 102 is Umin2, and the second conversion voltage of bidirectional DC-DC converter 20 is Vset2, where Vset2 is greater than or equal to the lowest operating voltage Umin2 of second DC bus 102. The control circuit of the bidirectional DC-DC converter 20 receives the parameters and controls the first interface and the second interface to be in an input, output or locking state according to the detected terminal voltage of the storage battery pack. Specifically, when the first end voltage corresponding to the first battery pack 301 is less than or equal to the first conversion voltage Vset1, and the second end voltage corresponding to the second battery pack 302 is greater than the lowest operating voltage Ubmin2 of the second battery pack 302, the control circuit of the bidirectional DC-DC converter 20 sets the second interface to the input state, sets the first interface to the output state, and outputs the first conversion voltage Vset 1; when the second terminal voltage corresponding to second battery pack 302 is equal to or less than second switching voltage Vset2, and the first terminal voltage corresponding to first battery pack 301 is greater than minimum operating voltage Ubmin1 of first battery pack 301, bidirectional DC-DC converter 20 sets the first interface to an input state, sets the second interface to an output state, and outputs the second switching voltage Vset 2.
If the direct current system has an alternating current grid power loss fault and the first storage battery pack 301 has an open-circuit fault at the same time, the second storage battery pack 302 is normal, and the corresponding second end voltage is greater than the lowest working voltage Ubmin 2. Because first battery pack 301 is open, the voltage of first DC bus 101 (here, the voltage of first DC bus 101 may be understood as the voltage of the first terminal corresponding to first battery pack 301) will continuously drop, and when the voltage of the first terminal drops to be less than or equal to first switching voltage Vset1, bidirectional DC-DC converter 20 automatically sets the second interface to the input state, sets the first interface to the output state, and the output voltage is Vset1, so that second battery pack 302 supplies power to first DC bus 101 through bidirectional DC-DC converter 20, thereby ensuring that first DC bus 101 will not lose power. During the discharging process of second battery pack 302, if bidirectional DC-DC converter 20 detects that the voltage at the second end corresponding to second battery pack 302 is less than or equal to minimum operating voltage Ubmin2, bidirectional DC-DC converter 20 will automatically turn off the output, so that second battery pack 302 is disconnected from first DC bus 101, and power supply to first DC bus 101 is stopped.
If the direct current system has an alternating current grid power loss fault and the second storage battery pack 302 has an open-circuit fault at the same time, the first storage battery pack 301 is normal, and the voltage of the corresponding first end is greater than the lowest working voltage Ubmin 1. Because second battery pack 302 is open, the voltage of second DC bus 102 (here, the voltage of second DC bus 102 is understood to be the second terminal voltage corresponding to second battery pack 302) will continuously drop, and when the second terminal voltage drops to be less than or equal to switching voltage Vset2, bidirectional DC-DC converter 20 automatically sets the first interface to the input state, sets the second interface to the output state, and the output voltage is Vset2, so that first battery pack 301 supplies power to second DC bus 102 through bidirectional DC-DC converter 20, and it is ensured that bidirectional DC-DC converter 20 does not lose power. During the discharging process of first battery pack 301, if bidirectional DC-DC converter 20 detects that the terminal voltage corresponding to first battery pack 301 is less than or equal to minimum operating voltage Ubmin1, bidirectional DC-DC converter 20 will automatically turn off the output, disconnect first battery pack 301 from second DC bus 102, and stop supplying power to second DC bus 102.
As can be seen from the above control process, the system monitor 40 presets the parameters required by the bidirectional DC-DC converter 20 during operation, and issues the preset parameters to the bidirectional DC-DC converter 20, and the bidirectional DC-DC converter 20 automatically operates according to the set parameters; when the power supply system simultaneously has alternating current power grid power failure and storage battery pack failure, the storage battery pack with normal terminal voltage automatically supplies power to the direct current bus corresponding to the failed storage battery pack through the bidirectional DC-DC converter 20, so that the direct current bus is prevented from losing power, and the power supply reliability of the direct current bus is improved.
Further, in some embodiments, the power supply system of the present invention further includes a first switch K1 and a second switch K2, where the first switch K1 is disposed between the first battery pack 301 and the first dc bus 101, and is used for controlling connection or disconnection between the first battery pack 301 and the first dc bus 101; second switch K2 is disposed between second battery pack 302 and second dc bus 102, and is used for controlling connection and disconnection of second battery pack 302 to and from second dc bus 102.
Specifically, the connection or disconnection of first battery pack 301 and first dc bus 101 may be controlled by first switch K1 provided between first battery pack 301 and first dc bus 101, and the connection or disconnection of second battery pack 302 and second dc bus 102 may be controlled by second switch K2 provided between second battery pack 302 and second dc bus 102. The direct current bus charging device is used for ensuring that the storage battery pack supplies power to the direct current bus or performs floating charging on the storage battery pack through the direct current bus during normal work.
Further, in some embodiments, the power supply system of the present invention further includes a third switch K3 and a fourth switch K4, where the third switch K3 is disposed between the first charger 501 and the first dc bus 101, and is used to control connection or disconnection between the first charger 501 and the first dc bus 101; the fourth switch K4 is disposed between the second charger 502 and the second dc bus 102, and is configured to control connection or disconnection between the second charger 502 and the second dc bus 102.
Specifically, the connection or disconnection between the first charger 501 and the first dc bus 101 can be controlled by a third switch K3 arranged between the first charger 501 and the first dc bus 101, and the connection or disconnection between the second charger 502 and the second dc bus 102 can be controlled by a fourth switch K4 arranged between the second charger 502 and the second dc bus 102, so as to ensure that the charger supplies power to the dc bus and charges the floating charge of the storage battery pack during normal operation.
Further, in some embodiments, the power supply system of the present invention further includes a fifth switch K5, where the fifth switch K5 is disposed between the first dc bus 101 and the second dc bus 102, and is used for controlling connection or disconnection of the first dc bus 101 and the second dc bus 102.
Specifically, the connection or disconnection of the first dc bus 101 and the second dc bus 102 may be controlled by a fifth switch K5 disposed between the first dc bus 101 and the second dc bus 102, and when the battery pack has a fault, the first dc bus 101 and the second dc bus 102 may supply power to each other by manually controlling the fifth switch K5 to be closed.
As shown in fig. 2, the present invention further provides a method for protecting a dc bus, including:
s1, the bidirectional DC-DC converter 20 detects and obtains a first terminal voltage and a second terminal voltage corresponding to the first battery pack 301 and the second battery pack 302, respectively;
s2, the bidirectional DC-DC converter 20 compares the first terminal voltage with the first converted voltage of the bidirectional DC-DC converter 20 and the second terminal voltage with the second converted voltage of the bidirectional DC-DC converter 20, respectively, performs step S21 if the first terminal voltage is less than or equal to the first converted voltage, performs step S22 if the second terminal voltage is less than or equal to the second converted voltage,
s21, the bidirectional DC-DC converter 20 controls the second storage battery pack 302 to be communicated with the first DC bus 101 and supplies power to the first DC bus 101;
s22, bidirectional DC-DC converter 20 controls first battery pack 301 to communicate with second DC bus 102, and supplies power to second DC bus 102.
Specifically, the system monitor 40 may set the lowest operating voltage of each DC bus, the lowest operating voltage of each battery pack, and the conversion voltage of the bidirectional DC-DC converter 20 according to the settings of various components of the power supply system, such as the voltage level of the power supply system, the voltage level of each battery pack, the number of batteries in each battery pack, and various configuration parameters of the power supply system, and send the lowest operating voltage of each battery pack and the conversion voltage of the bidirectional DC-DC converter 20 to the bidirectional DC-DC converter 20. The bi-directional DC-DC converter 20 receives and compares the first terminal voltage, the second terminal voltage and the converted voltage, wherein the converted voltage may include a first converted voltage and a second converted voltage, which are compared with the first terminal voltage and the second terminal voltage, respectively, and controls the first interface to be in an input, output or latch state and the second interface to be in an input, output or latch state according to the comparison result. It can be understood that the first interface and the second interface of the bidirectional DC-DC converter 20 are respectively connected to the first battery pack 301 and the second battery pack 302, and the bidirectional DC-DC converter 20 detects the voltage of the first interface and the voltage of the second interface in real time, which is equivalent to detecting the voltage of the first end of the first battery pack 301 and the voltage of the second end of the first battery pack 302 in real time. When one of the direct current buses is in fault and power loss, the terminal voltage of the storage battery pack correspondingly connected with the direct current bus is reduced, the bidirectional DC-DC converter 20 compares the terminal voltage with the corresponding conversion voltage, and controls the other storage battery pack to be communicated with the direct current bus corresponding to the fault storage battery pack so as to ensure that the direct current bus is not in power loss.
For example. If the direct current system has an alternating current grid power loss fault and the first storage battery pack 301 has an open-circuit fault at the same time, the second storage battery pack 302 is normal, and the corresponding second end voltage is greater than the lowest working voltage Ubmin 2. Because first battery pack 301 is open, the voltage of first DC bus 101 (here, the voltage of first DC bus 101 is understood to be the voltage of the first end corresponding to first battery pack 301) will continuously drop, and when the voltage of the first end drops to be equal to or less than Vset1 of the first conversion voltage of the bidirectional DC-DC converter, bidirectional DC-DC converter 20 controls second battery pack 302 to communicate with first DC bus 101, so that second battery pack 302 supplies power to first DC bus 101 through bidirectional DC-DC converter 20, and it is ensured that first DC bus 101 will not lose power. If the direct current system has an alternating current grid power loss fault and the second storage battery pack 302 has an open-circuit fault at the same time, the first storage battery pack 301 is normal, and the voltage of the corresponding first end is greater than the lowest working voltage Ubmin 1. Due to the open circuit of second battery pack 302, the voltage of second DC bus 102 (here, the voltage of second DC bus 102 is understood to be the second terminal voltage corresponding to second battery pack 302) will continuously decrease, and when the second terminal voltage decreases to be equal to or less than the second conversion voltage Vset2 to the DC-DC converter, first battery pack 301 supplies power to second DC bus 102 through bidirectional DC-DC converter 20, so as to ensure that second DC bus 102 does not lose power.
Further, in step S21, bidirectional DC-DC converter 20 controlling second battery pack 302 to communicate with first DC bus 101 includes: the bidirectional DC-DC converter 20 sets its first interface to an output state and sets its second interface to an input state; in step S22, bidirectional DC-DC converter 20 controlling first battery pack 301 to communicate with second DC bus 102 includes: the bidirectional DC-DC converter 20 sets the second interface to the output state and sets the first interface to the input state.
It is understood that bidirectional DC-DC converter 20 includes a first interface and a second interface, which are respectively connected to first battery pack 301 and second battery pack 302, and on the basis of the above, when bidirectional DC-DC converter 20 controls second battery pack 302 to communicate with first DC bus 101, the second interface can be automatically set to an input state, the first interface is set to an output state, and the output voltage is first converted voltage Vset 1. When bidirectional DC-DC converter 20 controls first battery pack 301 to communicate with second DC bus 102, bidirectional DC-DC converter 20 automatically sets the first interface to the input state and the second interface to the output state, outputting the voltage as second converted Vset 2.
As shown in fig. 3, in the dc bus protection method of the present invention, on the basis of the above embodiment, step S21 further includes: if the voltage at the second end is less than or equal to the lowest working voltage of the second battery pack 302, the bidirectional DC-DC converter 20 controls the second battery pack 302 to disconnect from the first DC bus 101 and stop supplying power to the first DC bus 101; step S22 further includes: if the first terminal voltage is less than or equal to the lowest working voltage of the first battery pack 301, the bidirectional DC-DC converter 20 controls the first battery pack 301 to be disconnected from the second DC bus 102, and stops supplying power to the second DC bus 102.
Specifically, if the second battery pack 302 and the first DC bus 101 are connected to supply power to the first DC bus 101, during the discharging process of the second battery pack 302, if the bidirectional DC-DC converter 20 detects that the voltage of the second end corresponding to the second battery pack 302 is less than or equal to the minimum operating voltage Ubmin2, the bidirectional DC-DC converter 20 will automatically turn off the output, so that the second battery pack 302 is disconnected from the first DC bus 101, and the power supply to the first DC bus 101 is stopped.
Further, in step S21, bidirectional DC-DC converter 20 controlling second battery pack 302 to be disconnected from first DC bus 101 includes: the bidirectional DC-DC converter 20 sets the first interface and the second interface to a locked state; in step S22, bidirectional DC-DC converter 20 controlling first battery pack 301 to be disconnected from second DC bus 102 includes: the bidirectional DC-DC converter 20 sets the first interface and the second interface to a blocking state.
It is understood that turning off the bidirectional DC-DC converter 20 may set the first and second interfaces of the bidirectional DC-DC converter 20 to a locked state.
The technical solution of the present invention is explained in detail by a specific application example.
Assuming that the system is a 220VDC system, two segments of direct current buses (i.e., the first direct current bus 101 and the second direct current bus 102), two sets of chargers (i.e., the first charger 501 and the first charger 501) and two sets of storage battery packs (i.e., the first storage battery pack 301 and the second storage battery pack 302), where the configurations of the first storage battery pack 301 and the second storage battery pack 302 are completely consistent and are 108 nodes each, the float voltage values of the two storage battery packs are both 108 × 2.23V — 241V, the lowest operating voltages of the two storage battery packs are both 108 × 1.8V — 194.4V, the lowest operating voltages of the two segments of direct current buses are both 220 × 0.875V — 192.5V, and the system monitor 40 sets the conversion voltages (corresponding to the first conversion voltage and the second conversion voltage, respectively) of the first interface and the second interface of the bidirectional DC-DC converter 20 to be slightly greater than the lowest operating voltage 192.5V of the direct current buses and set to be 195V; when the power supply system is normal, both the two storage battery packs are in a floating charge state, the terminal voltage is 241VDC, and the first interface and the second interface of the bidirectional DC-DC converter 20 are in a locked state, that is, the bidirectional DC-DC converter 20 is in a hot standby state without output. Assuming that the ac grid loss fault occurs in the dc system and the open circuit fault occurs in the first battery pack 301, the second battery pack 302 is normal and its terminal voltage is greater than the lowest operating voltage 194.4V. Because the first battery pack 301 is open, the voltage of the first DC bus 101 will continuously drop (here, the voltage of the first DC bus 101 can be understood as the voltage of the first end corresponding to the first battery pack 301), when the voltage of the first end drops to less than or equal to the conversion voltage 195V, the bidirectional DC-DC converter 20 automatically sets the second interface to the input state, sets the first interface to the output state, and has the output voltage of 195V, so that the second battery pack 302 automatically supplies power to the first DC bus 101 through the bidirectional DC-DC converter 20 and the switch K1, thereby ensuring that the first DC bus 101 is not powered off and improving the reliability of power supply of the DC bus. During the discharging process of second battery pack 302, if bidirectional DC-DC converter 20 detects that the voltage at the corresponding second terminal of second battery pack 302 is less than or equal to the lowest operating voltage 194.4V, bidirectional DC-DC converter 20 will automatically turn off the output, and set the first interface and the second interface to be in a locked state.
It is to be understood that the foregoing examples merely represent preferred embodiments of the present invention, and that the description thereof is more specific and detailed, but not intended to limit the scope of the invention; it should be noted that, for those skilled in the art, the above technical features can be freely combined, and several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention; therefore, all changes and modifications that come within the meaning and range of equivalency of the claims are to be embraced within their scope.
Claims (8)
1. The utility model provides a power supply system with direct current bus protect function, includes first storage battery and the first direct current bus of being connected with it, first machine that charges, second storage battery and the second direct current bus of being connected with it, second machine that charges which still includes its characterized in that:
a bidirectional DC-DC converter connected to the first battery pack and the second battery pack, respectively;
the system monitor is respectively connected with the first charger, the second charger and the bidirectional DC-DC converter;
wherein,
the system monitor is used for sending a conversion voltage to the bidirectional DC-DC converter;
the bidirectional DC-DC converter is used for receiving the conversion voltage, detecting a first end voltage of the first storage battery pack and a second end voltage of the second storage battery pack, and switching on or switching off according to the relation between the conversion voltage and the first end voltage and the second end voltage.
2. The power system of claim 1, wherein said bi-directional DC-DC converter comprises a first interface and a second interface, said first interface being coupled to said first battery pack and said second interface being coupled to said second battery pack.
3. The power supply system of claim 2, wherein the bidirectional DC-DC converter comprises a detection circuit coupled to the first interface for detecting the first terminal voltage and/or coupled to the second interface for detecting the second terminal voltage.
4. The power supply system according to claim 3, wherein the bidirectional DC-DC converter includes a control unit,
the control unit is connected with the detection circuit and the system monitor and used for receiving and comparing the first end voltage, the second end voltage and the conversion voltage so as to control the first interface and/or the second interface to be in an input, output or locking state.
5. The power supply system of claim 4, wherein the bidirectional DC-DC converter includes an isolation circuit for isolating the first battery pack and the second battery pack.
6. The power supply system according to claim 1, further comprising a first switch and a second switch, wherein the first switch is disposed between the first battery pack and the first dc bus, and is configured to control connection and disconnection of the first battery pack to and from the first dc bus; the second switch is arranged between the second storage battery pack and the second direct current bus and used for controlling the connection or disconnection of the second storage battery pack and the second direct current bus.
7. The power supply system according to claim 2, further comprising a third switch and a fourth switch, wherein the third switch is arranged between the first charger and the first dc bus and is used for controlling the connection or disconnection between the first charger and the first dc bus; the fourth switch is arranged between the second charger and the second direct-current bus and used for controlling the connection or disconnection of the second charger and the second direct-current bus.
8. The power supply system according to claim 3, further comprising a fifth switch provided between the first dc bus and the second dc bus for controlling connection and disconnection of the first dc bus and the second dc bus.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201820232709.8U CN208028641U (en) | 2018-02-07 | 2018-02-07 | Power-supply system with DC bus defencive function |
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| CN201820232709.8U CN208028641U (en) | 2018-02-07 | 2018-02-07 | Power-supply system with DC bus defencive function |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108233513A (en) * | 2018-02-07 | 2018-06-29 | 深圳奥特迅电力设备股份有限公司 | Power-supply system and dc bus guard method with dc bus defencive function |
| CN110492600A (en) * | 2019-09-06 | 2019-11-22 | 智洋创新科技股份有限公司 | Substation's novel intelligent DC power system and maintaining method |
-
2018
- 2018-02-07 CN CN201820232709.8U patent/CN208028641U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108233513A (en) * | 2018-02-07 | 2018-06-29 | 深圳奥特迅电力设备股份有限公司 | Power-supply system and dc bus guard method with dc bus defencive function |
| CN110492600A (en) * | 2019-09-06 | 2019-11-22 | 智洋创新科技股份有限公司 | Substation's novel intelligent DC power system and maintaining method |
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