A relief device and energy storage system

Abstract

This application provides a discharge device and an energy storage system. The energy storage system includes an energy storage battery and an energy storage converter connected in sequence. The discharge device includes an energy discharge unit and a control unit. The energy discharge unit is connected between the positive and negative buses of the energy storage converter. The control unit includes a delay module and a comparison module. The delay module generates a delayed detection signal based on a first detection signal, which indicates the bus voltage of the energy storage converter or the terminal voltage of the energy storage battery. The comparison module generates a control signal based on the delayed detection signal and a second detection signal. The control signal is used to control the energy discharge unit, and the second detection signal indicates the bus voltage of the energy storage converter. Therefore, through this solution, quantitative energy discharge from the bus capacitor can be achieved during low-voltage ride-through, thereby effectively maintaining the stability of the bus voltage and ensuring the reliability of the energy storage system.

Description

Technical Field

[0001] This application relates to the field of energy storage technology, specifically to a discharge device and an energy storage system. Background Technology

[0002] During low-voltage ride-through, a sudden drop in grid voltage can cause a sharp decrease in the AC output power of the energy storage converter. Meanwhile, the DC input power cannot be adjusted synchronously due to control delays and the current inertia of the energy storage battery, leading to a transient power imbalance. Excess energy accumulates in the bus capacitor of the energy storage converter, causing a rise in the bus voltage. This may trigger overvoltage protection, resulting in grid disconnection. In severe cases, it can cause the energy storage converter to fail due to excessive voltage stress. Furthermore, it may further lead to reverse charging of the energy storage battery, threatening the reliability of the energy storage system. Utility Model Content

[0003] In view of this, this application aims to provide a discharge device and energy storage system to solve the problem that the prior art cannot maintain the stability of the bus voltage and ensure the reliability of the energy storage system during low-voltage ride-through.

[0004] In a first aspect, this application provides a discharge device for use in an energy storage system, the energy storage system including an energy storage battery and an energy storage converter connected in sequence, the discharge device including: an energy discharge unit and a control unit;

[0005] The energy discharge unit is connected between the positive bus and the negative bus of the energy storage converter;

[0006] The control unit includes a delay module and a comparison module; the delay module generates a delay detection signal based on a first detection signal, the first detection signal indicating the bus voltage of the energy storage converter or the terminal voltage of the energy storage battery; the comparison module generates a control signal based on the delay detection signal and a second detection signal, the control signal being used to control the energy discharge unit, the second detection signal indicating the bus voltage of the energy storage converter.

[0007] In one optional implementation, a detection unit is further included, the output of which is connected to the input of the delay module and the input of the comparison module, respectively.

[0008] The detection unit is used to output the first detection signal to the delay module and to output the second detection signal to the comparison module.

[0009] In one optional implementation, the detection unit includes a terminal voltage detection module and a bus voltage detection module;

[0010] Wherein, the first input terminal of the terminal voltage detection module is connected to the positive terminal of the energy storage battery, the second input terminal of the terminal voltage detection module is connected to the negative terminal of the energy storage battery, and the output terminal of the terminal voltage detection module is connected to the input terminal of the delay module, so that the terminal voltage of the energy storage battery is output to the delay module as the first detection signal;

[0011] The first input terminal of the bus voltage detection module is connected to the positive bus of the energy storage converter, the second input terminal of the bus voltage detection module is connected to the negative bus of the energy storage converter, and the output terminal of the bus voltage detection module is connected to the input terminal of the comparison module, so that the bus voltage of the energy storage converter is output to the comparison module as the second detection signal.

[0012] In one optional implementation, the terminal voltage detection module employs a first differential amplifier circuit;

[0013] Wherein, the inverting input terminal of the first differential amplifier circuit serves as the first input terminal of the terminal voltage detection module, the non-inverting input terminal of the first differential amplifier circuit serves as the second input terminal of the terminal voltage detection module, the output terminal of the first differential amplifier circuit serves as the output terminal of the terminal voltage detection module, and the feedback resistance of the first differential amplifier circuit is less than the input resistance of the inverting input terminal of the first differential amplifier circuit.

[0014] In one optional implementation, the bus voltage detection module employs a second differential amplifier circuit;

[0015] In this circuit, the inverting input terminal of the second differential amplifier circuit serves as the first input terminal of the bus voltage detection module, the non-inverting input terminal of the second differential amplifier circuit serves as the second input terminal of the bus voltage detection module, the output terminal of the second differential amplifier circuit serves as the output terminal of the bus voltage detection module, and the feedback resistance of the second differential amplifier circuit is less than the input resistance of the inverting input terminal of the second differential amplifier circuit.

[0016] In one optional implementation, the detection unit includes a bus voltage detection module;

[0017] The first input terminal of the bus voltage detection module is connected to the positive bus of the energy storage converter, the second input terminal of the bus voltage detection module is connected to the negative bus of the energy storage converter, and the output terminal of the bus voltage detection module serves as the output terminal of the detection unit. The bus voltage of the energy storage converter is output to the delay module as the first detection signal, and output to the comparison module as the second detection signal.

[0018] In one optional implementation, the comparison module employs a hysteresis comparator;

[0019] The input terminal of the hysteresis comparator serves as the input terminal of the comparison module, and the output terminal of the hysteresis comparator serves as the output terminal of the comparison module.

[0020] In one optional implementation, the delay module employs a low-pass filter circuit;

[0021] The input terminal of the low-pass filter circuit serves as the input terminal of the delay module, and the output terminal of the low-pass filter circuit serves as the output terminal of the delay module.

[0022] In one alternative implementation, the energy dissipation unit includes a switching module and a dissipation resistor connected in series;

[0023] The control terminal of the switch module serves as the control terminal of the energy discharge unit, and is used to receive the control signal, which is used to control the switch module to close or open.

[0024] Secondly, this application provides an energy storage system, including: an energy storage converter, an energy storage battery, and a discharge device as described in the first aspect of this application.

[0025] Based on the above, the discharge device provided in this application is applied to an energy storage system, which includes an energy storage battery and an energy storage converter connected in sequence. The discharge device includes an energy discharge unit and a control unit. The energy discharge unit is connected between the positive bus and the negative bus of the energy storage converter. The control unit includes a delay module and a comparison module. The delay module generates a delayed detection signal based on a first detection signal. The first detection signal indicates the bus voltage of the energy storage converter or the terminal voltage of the energy storage battery. The comparison module generates a control signal based on the delayed detection signal and a second detection signal. The control signal is used to control the energy discharge unit. The second detection signal indicates the bus voltage of the energy storage converter. Thus, the comparison module can automatically control the energy discharge unit to discharge energy from the bus capacitor of the energy storage converter according to the comparison result between the bus voltage of the energy storage converter and the bus voltage or the terminal voltage of the energy storage battery before a preset time. In this way, during low-voltage ride-through, the energy in the bus capacitor can be quantitatively discharged, thereby effectively maintaining the stability of the bus voltage and ensuring the reliability of the energy storage system.

[0026] Furthermore, the comparison module automatically controls the energy discharge unit based on the comparison results between the bus voltage of the energy storage converter and the bus voltage or the terminal voltage of the energy storage battery before a preset time, which can be applied to different operating conditions of the energy storage system and greatly improves the applicability of the discharge device. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the structure of an energy storage system in the prior art.

[0029] Figure 2 This is a schematic diagram of the structure of a venting device provided in this application.

[0030] Figure 3 This is a schematic diagram of another venting device provided in this application.

[0031] Figure 4 This is a schematic diagram of the structure of a detection unit.

[0032] Figure 5 This is a circuit topology diagram of a detection unit provided in this application.

[0033] Figure 6 This is a schematic diagram of another detection unit provided in this application.

[0034] Figure 7 This is a circuit topology diagram of a delay module provided in this application.

[0035] Figure 8 This is a schematic diagram of the structure of an energy release unit provided in this application.

[0036] Figure 9 This is a structural schematic diagram of another type of venting device provided in this application. Detailed Implementation

[0037] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0038] Combination Figure 1 In practical applications, the energy storage battery 101 in the energy storage system is connected to the power grid via the energy storage converter 102. The positive terminal of the energy storage battery 101 is connected to the positive terminal via a positive switch K. M1 The negative terminal of the energy storage battery 101 is connected to the positive bus of the energy storage converter 102 and connected to the negative switch K. M2Connected to the negative bus of the energy storage converter 102, the energy storage converter 102 includes a first bus capacitor C. bus1 Second bus capacitor C bus2 The inverter circuit 1021, and the three-phase AC terminals of the inverter circuit 1021 are respectively connected to the first grid-connected inductor L g1 Second grid-connected inductor L g2 and the third grid-connected inductor L g3 The energy storage converter 102 can be connected to the power grid to convert the electrical energy output from the energy storage battery 101 into power before feeding it into the grid, or to convert the electrical energy supplied by the grid into power to charge the energy storage battery 101. Additionally, the AC terminal of the energy storage converter 102 can also be connected to a load to convert the electrical energy output from the energy storage battery 101 into power to supply power to the load. It should be noted that... Figure 1 The diagram only illustrates the energy storage converter 102 as a three-phase three-level energy storage converter. The energy storage converter 102 can also be a single-phase energy storage converter, or it can be a two-level topology. This application does not limit this.

[0039] During low-voltage ride-through, a sudden drop in grid voltage causes a sharp decrease in the output power of the AC side of the energy storage converter 102, while the input power on the DC side cannot be adjusted synchronously due to control delays and the current inertia of the energy storage battery 101, thus triggering a momentary power imbalance. Excess energy is stored in the bus capacitor (C) of the energy storage converter 102. bus1 and C bus2 Accumulation of voltage stress in the energy storage converter 102 can cause the bus voltage of the energy storage converter 102 to rise, which may trigger overvoltage protection and cause the equipment to disconnect from the grid. In severe cases, the energy storage converter 102 may fail due to excessive voltage stress. In addition, it may also cause the energy storage battery 101 to be reverse charged, threatening the reliability of the energy storage system.

[0040] To address the aforementioned issues, this application provides a discharge device comprising an energy discharge unit and a control unit. The control unit can automatically control the energy discharge unit to discharge energy from the bus capacitor of the energy storage converter 102 based on a comparison between the bus voltage of the energy storage converter 102 and the bus voltage or the terminal voltage of the energy storage battery 101 before a preset time period. This enables quantitative energy discharge from the bus capacitor during low-voltage ride-through, thereby effectively maintaining the stability of the bus voltage and ensuring the reliability of the energy storage system.

[0041] Furthermore, the comparison module automatically controls the energy discharge unit based on the comparison result of the bus voltage of the energy storage converter 102 with the bus voltage before a preset time or the terminal voltage of the energy storage battery 101 before a preset time. This makes it applicable to different operating conditions of the energy storage system and greatly improves the applicability of the discharge device.

[0042] The following is combined with Figure 1 The application scenarios shown are used to exemplarily describe the venting device proposed in the embodiments of this application.

[0043] Reference Figure 2 This application first proposes a discharge device for use in an energy storage system. The energy storage system includes an energy storage battery 101 and an energy storage converter 102 connected in sequence. The discharge device includes an energy discharge unit 103 and a control unit 104.

[0044] The energy discharge unit 103 is connected between the positive bus and the negative bus of the energy storage converter 102;

[0045] The control unit 104 includes a delay module 1041 and a comparison module 1042; the delay module 1041 generates a delay detection signal based on a first detection signal, the first detection signal indicating the bus voltage of the energy storage converter 102 or the terminal voltage of the energy storage battery 101; the comparison module 1042 generates a control signal based on the delay detection signal and a second detection signal, the control signal being used to control the energy discharge unit 103, the second detection signal indicating the bus voltage of the energy storage converter 102.

[0046] Specifically, one end of the energy discharge unit 103 is connected to the positive bus of the energy storage converter 102, and the other end is connected to the negative bus of the energy storage converter 102. Thus, the energy discharge unit 103 and the bus capacitor of the energy storage converter 102 can form a circuit. The energy discharge unit 103 may include a discharge resistor, which dissipates the energy in the bus capacitor to achieve energy discharge. Optionally, the energy discharge unit 103 may also include a switching module. The control signal output by the control unit 104 can be used to control the closing or opening of the switching module. When the switching module is closed, the circuit is open, and the energy in the bus capacitor can be dissipated through the discharge resistor. When the energy discharge unit 103 is open, the circuit is closed, and the discharge resistor stops dissipating the energy in the bus capacitor. Furthermore, the discharge resistor can adjust its operating power according to the control signal to regulate the energy consumed by the discharge resistor.

[0047] The control unit 104 outputs control signals to the energy discharge unit 103 to control the energy discharge unit 103 to discharge energy from the bus capacitor. The control unit 104 may include a delay module 1041 and a comparison module 1042.

[0048] The output of the delay module 1041 is connected to the input of the comparison module 1042. It receives the first detection signal and generates a delayed detection signal based on the first detection signal. For example, the delay module 1041 can delay the first detection signal for a preset time and then output it as a delayed detection signal to the comparison module 1042. The first detection signal can indicate the bus voltage of the energy storage converter 102 or the terminal voltage of the energy storage battery 101. The terminal voltage of the energy storage battery 101 is the voltage between the positive and negative terminals of the energy storage battery 101. The delayed detection signal can be the bus voltage before the preset time or the terminal voltage of the energy storage battery 101 before the preset time.

[0049] In practical applications, the type of delay module 1041 can be selected according to the accuracy requirements of the delay and the preset duration. For example, it can be a low-pass filter circuit, or a microcontroller, analog memory, delay line, etc. Any device or circuit that can delay the input signal for a controllable duration before outputting is optional, and will not be listed here.

[0050] The input terminal of the comparison module 1042 is also used to receive a second detection signal, which can indicate the bus voltage of the energy storage converter 102. The comparison module 1042 can generate a control signal based on the delayed detection signal and the second detection signal. For example, at any moment during the operation of the control unit 104, the comparison module 1042 can generate a control signal based on the magnitude relationship between the second detection signal and the delayed detection signal, or based on the difference between the second detection signal and the delayed detection signal.

[0051] The output terminal of the comparator module 1042 is connected to the control terminal of the energy discharge unit 103, and outputs a control signal to the control terminal of the energy discharge unit 103 to control the energy discharge unit 103 to discharge energy from the bus capacitor. Optionally, the control signal can be a level signal, such as a first level signal or a second level signal. The first level signal can be used to control the energy discharge unit 103 to discharge energy from the bus capacitor, and the second level signal can be used to control the energy discharge unit 103 to stop discharging energy from the bus capacitor.

[0052] Optionally, the comparison module 1042 can be a basic voltage comparator. That is, the comparison module 1042 can output a corresponding control signal to the control terminal of the energy discharge unit 103 according to the magnitude relationship between the second detection signal and the delay detection signal. For example, when the second detection signal is greater than the delay detection signal, the output control signal is a first level signal, and when the second detection signal is less than or equal to the delay detection signal, the output control signal is a second level signal.

[0053] The comparison module 1042 can also employ a hysteresis comparator, which can be configured with a first threshold and a second threshold, wherein the first threshold is greater than the second threshold. For example, when the difference between the second detection signal and the delayed detection signal is greater than the first threshold, the output control signal is a first-level signal; when the difference between the second detection signal and the delayed detection signal is less than the second threshold, the output control signal is a second-level signal; and when the difference between the second detection signal and the delayed detection signal is less than or equal to the first threshold and greater than or equal to the second threshold, the control signal output to the control terminal of the energy discharge unit 103 remains unchanged.

[0054] Additionally, the comparison module 1042 may also include a differential amplifier and a comparator. The first input terminal of the differential amplifier serves as the first input terminal of the comparison module 1042 for receiving the second detection signal. The second input terminal of the differential amplifier serves as the second input terminal of the comparison module 1042 for receiving the delay detection signal. The output terminal of the differential amplifier is connected to the first input terminal of the comparator. The second input terminal of the comparator is used to receive a preset threshold. The output terminal of the comparator serves as the output terminal of the comparison module 1042. When the difference between the second detection signal and the delay detection signal is greater than the preset threshold, the control signal output by the comparison module 1042 can be a first-level signal. When the difference between the second detection signal and the delay detection signal is less than or equal to the preset threshold, the control signal output by the comparison module 1042 can be a second-level signal.

[0055] In the case where the first detection signal is the bus voltage of the energy storage converter 102, by configuring the delay module 1041 to delay the output of the first detection signal for a preset duration, the delayed detection signal output by the delay module 1041 to the comparison module 1042 during the entire low-voltage ride-through process is the bus voltage of the energy storage converter 102 before the low-voltage ride-through, thereby accurately controlling the energy discharge unit 103 to discharge energy.

[0056] When the first detection signal is the terminal voltage of the energy storage battery 101, considering the parasitic resistance on the connection line between the energy storage battery 101 and the bus of the energy storage converter 102, and the positive switch K installed between the energy storage battery 101 and the bus of the energy storage converter 102... M1 and negative switch K M2 The battery itself has a large resistance, which clamps the terminal voltage of the energy storage battery 101 to be the same as the bus voltage of the energy storage converter 102. By configuring the delay module 1041 to delay the output of the first detection signal for a preset time, the delayed detection signal output by the delay module 1041 to the comparison module 1042 during the entire low-voltage ride-through process is the terminal voltage of the energy storage battery 101 before the low-voltage ride-through, thereby accurately controlling the energy discharge unit 103 to discharge energy.

[0057] Therefore, the discharge device provided in this embodiment can quantitatively discharge the energy in the bus capacitor during low-voltage ride-through, thereby effectively maintaining the stability of the bus voltage and ensuring the reliability of the energy storage system.

[0058] Meanwhile, the operating voltage of the energy storage system is not fixed. For example, the operating voltage of the energy storage system can vary between 1000VDC and 1500VDC. In the discharge device provided in this embodiment, the comparison module 1042 automatically controls the energy discharge unit 103 to discharge energy based on the comparison result between the bus voltage of the energy storage converter 102 and the bus voltage or the terminal voltage of the energy storage battery 101 before a preset time. Under different operating voltages of the energy storage system, the energy discharge unit 103 can be effectively controlled, which greatly improves the applicability of the discharge device.

[0059] In some embodiments, reference Figure 3 It also includes a detection unit 105, the output of which is connected to the input of the delay module 1041 and the input of the comparison module 1042, respectively.

[0060] The detection unit 105 is used to output the first detection signal to the delay module 1041 and the second detection signal to the comparison module 1042.

[0061] Specifically, the detection unit 105 can be used to detect the bus voltage of the energy storage converter 102. In addition, the detection unit 105 can also be used to detect the terminal voltage of the energy storage battery 101. The output terminal of the detection unit 105 can be connected to the input terminal of the delay module 1041 and the input terminal of the comparison module 1042 respectively, so as to output the bus voltage of the energy storage converter 102 or the terminal voltage of the energy storage battery 101 as the first detection signal to the delay module 1041, and output the bus voltage of the energy storage converter 102 as the second detection signal to the comparison module 1042.

[0062] In some embodiments, reference Figure 4 The detection unit 105 includes a terminal voltage detection module 1051 and a bus voltage detection module 1052.

[0063] Wherein, the first input terminal of the terminal voltage detection module 1051 is connected to the positive terminal of the energy storage battery 101, the second input terminal of the terminal voltage detection module 1051 is connected to the negative terminal of the energy storage battery 101, and the output terminal of the terminal voltage detection module 1051 is connected to the input terminal of the delay module 1041, so that the terminal voltage of the energy storage battery 101 is output to the delay module 1041 as the first detection signal;

[0064] The first input terminal of the bus voltage detection module 1052 is connected to the positive bus of the energy storage converter 102, the second input terminal of the bus voltage detection module 1052 is connected to the negative bus of the energy storage converter 102, and the output terminal of the bus voltage detection module 1052 is connected to the input terminal of the comparison module 1042. The bus voltage of the energy storage converter 102 is output to the comparison module 1042 as the second detection signal.

[0065] Specifically, the first input terminal of the terminal voltage detection module 1051 can be connected to the positive terminal of the energy storage battery 101, the second input terminal of the terminal voltage detection module 1051 can be connected to the negative terminal of the energy storage battery 101, and the output terminal of the terminal voltage detection module 1051 is connected to the input terminal of the delay module 1041, so as to detect the terminal voltage of the energy storage battery 101 through the terminal voltage detection module 1051 and output the terminal voltage of the energy storage battery 101 as the first detection signal to the delay module 1041.

[0066] The first input terminal of the bus voltage detection module 1052 can be connected to the positive bus of the energy storage converter 102, and the second input terminal of the bus voltage detection module 1052 can be connected to the negative bus of the energy storage converter 102. The output terminal of the bus voltage detection module 1052 is connected to the first input terminal of the comparison module 1042, so as to detect the bus voltage of the energy storage converter 102 through the bus voltage detection module 1052, and output the bus voltage of the energy storage converter 102 as the second detection signal to the comparison module 1042.

[0067] Therefore, at any moment during the operation of the control unit 104, the comparison module 1042 can control the energy discharge unit 103 to discharge energy based on the comparison result of the bus voltage at that moment and the terminal voltage of the energy storage battery 101 before the preset time. This enables accurate control of the energy discharge unit 103, thereby further improving the stability of the bus voltage and the reliability of the energy storage system during low-voltage ride-through.

[0068] In practical applications, the types of terminal voltage detection module 1051 and bus voltage detection module 1052 can be set according to actual needs. For example, differential amplifier circuits, voltage followers, resistor divider circuits, etc. can be used.

[0069] In some embodiments, the terminal voltage detection module 1051 employs a first differential amplifier circuit;

[0070] Wherein, the inverting input terminal of the first differential amplifier circuit serves as the first input terminal of the terminal voltage detection module 1051, the non-inverting input terminal of the first differential amplifier circuit serves as the second input terminal of the terminal voltage detection module 1051, the output terminal of the first differential amplifier circuit serves as the output terminal of the terminal voltage detection module 1051, and the feedback resistance of the first differential amplifier circuit is less than the input resistance of the inverting input terminal of the first differential amplifier circuit.

[0071] Specifically, the terminal voltage detection module 1051 can employ a first differential amplifier circuit, as shown in the reference. Figure 5 The first differential amplifier circuit may include a first operational amplifier U1, a first resistor R1, a second resistor R2, a third resistor R3, and a fourth resistor R4. The inverting input terminal of the first operational amplifier U1 is the inverting input terminal of the first differential amplifier circuit, the non-inverting input terminal of the first operational amplifier U1 is the non-inverting input terminal of the first differential amplifier circuit, and the output terminal of the first operational amplifier U1 is the output terminal of the first differential amplifier circuit.

[0072] In this circuit, the inverting input of the first operational amplifier U1 is connected to the positive terminal of the energy storage battery 101 via the first resistor R1, meaning that the first resistor R1 is the input resistance of the inverting input of the first differential amplifier circuit; the non-inverting input of the first operational amplifier U1 is connected to the negative terminal of the energy storage battery 101 via the second resistor R2, meaning that the second resistor R2 is the input resistance of the non-inverting input of the first differential amplifier circuit; one end of the third resistor R3 is connected to the non-inverting input of the first operational amplifier U1, and the other end is connected to the output of the first operational amplifier U1, meaning that the third resistor R3 is the feedback resistor of the first differential amplifier circuit; one end of the fourth resistor R4 is connected to the non-inverting input of the first operational amplifier U1, and the other end is grounded.

[0073] In this circuit, the first resistor R1 is equal to the second resistor R2, and the third resistor R3 is equal to the fourth resistor R4. The first differential amplifier circuit is used to scale the voltage difference between the positive and negative terminals of the energy storage battery 101 according to the first preset scaling ratio, and output it as the terminal voltage of the energy storage battery 101 to the delay module 1041. The first preset scaling ratio is R3 / R1, which can effectively improve the reliability of the detection result of the terminal voltage of the energy storage battery 101. In the process of controlling the energy discharge unit 103 according to the terminal voltage of the energy storage battery 101, the stability of the bus voltage of the energy storage converter 102 and the reliability of the energy storage system during low voltage ride-through can be further improved.

[0074] In practical applications, the terminal voltage of the energy storage battery 101 is typically on the order of kV. Therefore, by setting the third resistor R3 to be smaller than the first resistor R1, the terminal voltage of the energy storage battery 101 can be reduced before being output to the delay module 1041. This effectively improves the detection accuracy of the terminal voltage of the energy storage battery 101 and avoids damage to the delay module 1041 and the comparison module 1042 by a large signal, thus achieving safe and effective operation of the discharge device.

[0075] In some embodiments, the bus voltage detection module 1052 employs a second differential amplifier circuit;

[0076] Wherein, the inverting input terminal of the second differential amplifier circuit serves as the first input terminal of the bus voltage detection module 1052, the non-inverting input terminal of the second differential amplifier circuit serves as the second input terminal of the bus voltage detection module 1052, the output terminal of the second differential amplifier circuit serves as the output terminal of the bus voltage detection module 1052, and the feedback resistance of the second differential amplifier circuit is less than the input resistance of the inverting input terminal of the second differential amplifier circuit.

[0077] Specifically, the bus voltage detection module 1052 can employ a second differential amplifier circuit, see reference. Figure 5 The second differential amplifier circuit may include a second operational amplifier U2, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, and an eighth resistor R8. The inverting input terminal of the second operational amplifier U2 is the inverting input terminal of the second differential amplifier circuit, the non-inverting input terminal of the second operational amplifier U2 is the non-inverting input terminal of the second differential amplifier circuit, and the output terminal of the second operational amplifier U2 is the output terminal of the second differential amplifier circuit.

[0078] Specifically, the inverting input terminal of the second operational amplifier U2 is connected to the positive bus of the energy storage converter 102 via the fifth resistor R5, meaning that the fifth resistor R5 is the input resistance of the inverting input terminal of the second differential amplifier circuit; the non-inverting input terminal of the second operational amplifier U2 is connected to the negative bus of the energy storage converter 102 via the sixth resistor R6, meaning that the sixth resistor R6 is the input resistance of the non-inverting input terminal of the second differential amplifier circuit; one end of the seventh resistor R7 is connected to the inverting input terminal of the second operational amplifier U2, and the other end is connected to the output terminal of the second operational amplifier U2, meaning that the seventh resistor R7 is the feedback resistor of the second differential amplifier circuit; one end of the eighth resistor R8 is connected to the non-inverting input terminal of the second operational amplifier U2, and the other end is grounded.

[0079] In this circuit, the fifth resistor R5 is equal to the sixth resistor R6, and the seventh resistor R7 is equal to the eighth resistor R8. The second differential amplifier circuit is used to scale the voltage difference between the positive and negative bus of the energy storage converter 102 according to the second preset scaling ratio, and output it as the bus voltage of the energy storage converter 102 to the comparison module 1042. The second preset scaling ratio is R7 / R5, which can effectively improve the reliability of the detection result of the bus voltage of the energy storage converter 102. In the process of controlling the energy discharge unit 103 according to the bus voltage of the energy storage converter 102, the stability of the bus voltage of the energy storage converter 102 and the reliability of the energy storage system can be further improved during the low-voltage ride-through.

[0080] In practical applications, the bus voltage of the energy storage converter 102 is typically on the order of kV. Therefore, by setting the seventh resistor R7 to be smaller than the fifth resistor R5, the bus voltage of the energy storage converter 102 can be reduced before being output to the comparison module 1042. This effectively improves the detection accuracy of the bus voltage of the energy storage converter 102 and avoids damage to the comparison module 1042 by a large signal, thus achieving safe and effective operation of the discharge device.

[0081] Understandably, the second preset scaling ratio is the same as the first preset scaling ratio to ensure the validity of the comparison result between the bus voltage of the energy storage converter 102 and the terminal voltage of the energy storage battery 101 before the preset time period.

[0082] In some embodiments, reference Figure 6 The detection unit 105 includes a bus voltage detection module 1052;

[0083] The first input terminal of the bus voltage detection module 1052 is connected to the positive bus of the energy storage converter 102, and the second input terminal of the bus voltage detection module 1052 is connected to the negative bus of the energy storage converter 102. The output terminal of the bus voltage detection module 1052 serves as the output terminal of the detection unit 105, outputting the bus voltage of the energy storage converter 102 as the first detection signal to the delay module 1041, and as the second detection signal to the comparison module 1042.

[0084] Specifically, the first input terminal of the bus voltage detection module 1052 is connected to the positive bus of the energy storage converter 102, the second input terminal of the bus voltage detection module 1052 is connected to the negative bus of the energy storage converter 102, and the output terminal of the bus voltage detection module 1052 serves as the output terminal of the detection unit 105. It is connected to the input terminal of the delay module 1041 and the input terminal of the comparison module 1042, respectively, so as to detect the bus voltage of the energy storage converter 102 through the bus voltage detection module 1052, output the bus voltage of the energy storage converter 102 as the first detection signal to the delay module 1041, and output the bus voltage of the energy storage converter 102 as the second detection signal to the comparison module 1042.

[0085] Therefore, at any moment during the operation of the control unit 104, the comparison module 1042 can control the energy discharge unit 103 to discharge energy based on the comparison result of the bus voltage at that moment and the bus voltage before the preset time, thereby achieving accurate control of the energy discharge unit 103. In turn, during the low-voltage ride-through process, the stability of the bus voltage of the energy storage converter 102 and the reliability of the energy storage system can be further improved.

[0086] In some embodiments, the comparison module 1042 employs a hysteresis comparator;

[0087] The input terminal of the hysteresis comparator serves as the input terminal of the comparison module 1042, and the output terminal of the hysteresis comparator serves as the output terminal of the comparison module 1042.

[0088] Specifically, the comparison module 1042 can be a hysteresis comparator. The first input terminal of the hysteresis comparator serves as the first input terminal of the comparison module 1042 to receive the second detection signal. The second input terminal of the hysteresis comparator serves as the second input terminal of the comparison module 1042 to receive the delay detection signal. The output terminal of the hysteresis comparator serves as the output terminal of the comparison module 1042 to output a control signal to the energy discharge unit 103.

[0089] In practical applications, a first threshold and a second threshold can be pre-configured in the hysteresis comparator according to the control accuracy requirements of the energy discharge unit 103 and the state switching frequency limit of the energy discharge unit 103, with the first threshold being greater than the second threshold.

[0090] When the difference between the second detection signal and the delay detection signal output by the delay module 1041 is greater than the first threshold, the control signal output by the hysteresis comparator can be a first level signal. The first level signal can be used to control the energy discharge unit 103 to discharge energy from the bus capacitor. Thus, when the bus voltage of the energy storage converter 102 is significantly higher than the bus voltage before the preset time or the terminal voltage of the energy storage battery 101 before the preset time, the energy discharge unit 103 can be controlled to consume the excess energy in the bus capacitor, thereby effectively ensuring the stability of the bus voltage and the reliability of the energy storage system.

[0091] When the difference between the second detection signal and the delay detection signal output by the delay module 1041 is less than the second threshold, the control signal output by the hysteresis comparator can be a second-level signal. The second-level signal can be used to control the energy discharge unit 103 to stop discharging energy from the bus capacitor. Thus, when the bus voltage of the energy storage converter 102 is slightly higher than the bus voltage before the preset time or the terminal voltage of the energy storage battery 101 before the preset time, or when the bus voltage of the energy storage converter 102 is less than or equal to the bus voltage before the preset time or the terminal voltage of the energy storage battery 101 before the preset time, the energy discharge unit 103 can be controlled to stop consuming the energy in the bus capacitor, thereby effectively ensuring the stability of the bus voltage.

[0092] In addition, when the difference between the second detection signal and the delayed detection signal output by the delay module 1041 is less than or equal to the first threshold and greater than or equal to the second threshold, the control signal output by the hysteresis comparator can keep the current control signal unchanged. This can prevent the energy discharge unit 103 from frequently switching its operating state when there are slight fluctuations in the bus voltage, thereby improving the stability of the bus voltage and ensuring the stable operation of the discharge device.

[0093] In some embodiments, the delay module 1041 employs a low-pass filter circuit;

[0094] The input terminal of the low-pass filter circuit serves as the input terminal of the delay module 1041, and the output terminal of the low-pass filter circuit serves as the output terminal of the delay module 1041.

[0095] Specifically, the delay module 1041 can employ a low-pass filter circuit, such as an LC filter circuit or an RC filter circuit. Due to the frequency response characteristics of the low-pass filter circuit, when the first detection signal input to the low-pass filter circuit undergoes a signal abrupt change, the low-pass filter circuit can delay the first detection signal for a certain period of time before it is input to the comparison module 1042. In practical applications, a first-order or multi-order low-pass filter circuit can be set according to the preset delay time of the first detection signal output by the delay module 1041.

[0096] In addition, the first detection signal is delayed by using a low-pass filter circuit, which has a simple structure, high reliability, and further improves the control accuracy of the energy discharge unit 103.

[0097] Optionally, the low-pass filter circuit can be a first-order LC filter circuit, see reference. Figure 7 A first-order LC filter circuit includes a filter inductor L. f and filter capacitor C f Filter inductor L f The first terminal serves as the input terminal of the low-pass filter circuit and is connected to the output terminal of the detection unit 105. The filter inductor L f The second terminal is connected to the filter capacitor C f The first terminal is connected to the filter capacitor C. f The second terminal is grounded, and the filter inductor L f The second terminal is connected to the filter capacitor C f The connection point of the first end serves as the output of the low-pass filter circuit and is connected to the input of the comparator module 1042.

[0098] In some embodiments, reference Figure 8 The energy dissipation unit 103 includes a series-connected switching module K C And a bleeder resistor of 1031;

[0099] Among them, the switch module K C The control terminal serves as the control terminal of the energy discharge unit 103, used to receive the control signal, which is used to control the switching module K. C To close or open.

[0100] Specifically, the energy dissipation unit 103 may include a series-connected switch module K C And a bleeder resistor of 1031.

[0101] Switch module K C Used to control the on / off state of energy discharge unit 103, in switch module K C When closed, the energy discharge unit 103 is turned on, and the switching module K... CWhen disconnected, the energy discharge unit 103 is disconnected. The discharge resistor 1031 is used to consume the energy input to the energy discharge unit 103. When the energy discharge unit 103 is on, it forms a closed loop with the bus capacitor of the energy storage converter 102. Thus, the energy in the bus capacitor is input to the energy discharge unit 103 and consumed by the discharge resistor 1031 to achieve energy discharge from the bus capacitor. When the energy discharge unit 103 is disconnected, the energy in the bus capacitor stops being input to the energy discharge unit 103, that is, energy discharge from the bus capacitor through the energy discharge unit 103 stops, thereby avoiding continuous energy waste during the grid-connected operation of the energy storage converter 102.

[0102] In practical applications, switch module K C A controllable switch can be selected to achieve this. The type of controllable switch can be determined according to actual needs, such as MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor), IGBT (Insulated-Gate Bipolar Transistor), and relays. Any controllable switch that can respond to control signals and change its own conduction state is optional, and will not be listed here.

[0103] Switch module K C The control terminal of the energy discharge unit 103 is connected to the output terminal of the comparison module 1042, so as to control the switch module K through the control signal output by the comparison module 1042. C To close or open.

[0104] In some embodiments, reference Figure 9 It also includes a drive unit 106, the input terminal of which is connected to the output terminal of the comparison module 1042, and the output terminal of the drive unit 106 is connected to the switch module K. C The control terminal is connected.

[0105] Specifically, the drive unit 106 is used to drive the switch module K according to the control signal output by the comparison module 1042. C Close or open. The type of drive unit 106 can be determined according to the switch module K. C The type determines the type of drive circuit; for example, it can be a voltage-type drive circuit, a current-type drive circuit, etc.

[0106] The drive unit 106 can effectively enhance the control of the switching module K. C Drive capability, improve the switching module K CThe switching speed is used to control the switching module K. C Stable and reliable control.

[0107] The detection unit 105 includes a terminal voltage detection module 1051 and a bus voltage detection module 1052. The comparison module 1042 uses a hysteresis comparator. The energy discharge unit 103 includes a series-connected switch module K. C Taking the bleeder resistor 1031 as an example, the working process of the bleeder device provided in this application is described in detail.

[0108] During the operation of the energy storage system, the switching module K in the energy discharge unit 103 C The system is in a default off state. The terminal voltage detection module 1051 detects the terminal voltage of the energy storage battery 101 in real time and outputs it to the delay module 1041. After a preset delay, the signal is output as a delay detection signal to the comparison module 1042. The bus voltage detection module 1052 detects the bus voltage of the energy storage converter 102 in real time and outputs it to the comparison module 1042. The comparison module 1042 compares the two received signals in real time. When the difference between the bus voltage and the delay detection signal is greater than a first threshold, it outputs a first-level signal to the drive unit 106 to drive the switch module K. C When closed, the discharge resistor 1031 in the energy discharge unit 103 consumes excess energy in the bus capacitor of the energy storage converter 102 until the difference between the bus voltage and the terminal voltage of the energy storage battery 101 is less than a first threshold. Then, a second level signal is output to the drive unit 106 to drive the switch module K through the drive unit 106. C Disconnection allows the bus voltage to return to normal levels, thus enabling quantitative discharge of the bus voltage and greatly improving the stability of the bus voltage and the reliability of the energy storage system during low-voltage ride-through.

[0109] This application also provides an energy storage system, including: an energy storage converter 102, an energy storage battery 101, and a discharge device provided in any of the foregoing embodiments of this application.

[0110] Those skilled in the art will understand that the content disclosed in this application can be varied and modified in many ways. For example, the various devices or components described above can be implemented by hardware, or by software, firmware, or a combination of some or all of the three.

[0111] Furthermore, while this application makes various references to certain units in the systems according to embodiments of this application, any number of different units can be used and run on the client and / or server. The units are merely illustrative, and different aspects of the system and method may use different units.

[0112] Unless otherwise defined, all terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. It should also be understood that terms such as those defined in a common dictionary should be interpreted as having a meaning consistent with their meaning in the context of the relevant art, and not as having an idealized or highly formalized meaning, unless expressly defined herein.

[0113] The foregoing description is intended to illustrate this application and should not be construed as limiting it. While several exemplary embodiments of this application have been described, those skilled in the art will readily understand that many modifications can be made to the exemplary embodiments without departing from the novel teachings and advantages of this application. Therefore, all such modifications are intended to be included within the scope of this application as defined by the claims. It should be understood that the foregoing description is intended to illustrate this application and should not be construed as limiting it to the specific embodiments disclosed, and modifications to the disclosed embodiments and other embodiments are intended to be included within the scope of the appended claims. This application is defined by the claims and their equivalents.

Claims

1. A venting device, characterized in that, Applied to an energy storage system, the energy storage system includes an energy storage battery and an energy storage converter connected in sequence, and the discharge device includes: an energy discharge unit and a control unit; The energy discharge unit is connected between the positive bus and the negative bus of the energy storage converter; The control unit includes a delay module and a comparison module; the delay module generates a delay detection signal based on a first detection signal, the first detection signal indicating the bus voltage of the energy storage converter or the terminal voltage of the energy storage battery; the comparison module generates a control signal based on the delay detection signal and a second detection signal, the control signal being used to control the energy discharge unit, the second detection signal indicating the bus voltage of the energy storage converter.

2. The venting device according to claim 1, characterized in that, It also includes a detection unit, the output of which is connected to the input of the delay module and the input of the comparison module, respectively. The detection unit is used to output the first detection signal to the delay module and to output the second detection signal to the comparison module.

3. The venting device according to claim 2, characterized in that, The detection unit includes a terminal voltage detection module and a bus voltage detection module; Wherein, the first input terminal of the terminal voltage detection module is connected to the positive terminal of the energy storage battery, the second input terminal of the terminal voltage detection module is connected to the negative terminal of the energy storage battery, and the output terminal of the terminal voltage detection module is connected to the input terminal of the delay module, so that the terminal voltage of the energy storage battery is output to the delay module as the first detection signal; The first input terminal of the bus voltage detection module is connected to the positive bus of the energy storage converter, the second input terminal of the bus voltage detection module is connected to the negative bus of the energy storage converter, and the output terminal of the bus voltage detection module is connected to the input terminal of the comparison module, so that the bus voltage of the energy storage converter is output to the comparison module as the second detection signal.

4. The venting device according to claim 3, characterized in that, The terminal voltage detection module employs a first differential amplifier circuit; Wherein, the inverting input terminal of the first differential amplifier circuit serves as the first input terminal of the terminal voltage detection module, the non-inverting input terminal of the first differential amplifier circuit serves as the second input terminal of the terminal voltage detection module, the output terminal of the first differential amplifier circuit serves as the output terminal of the terminal voltage detection module, and the feedback resistance of the first differential amplifier circuit is less than the input resistance of the inverting input terminal of the first differential amplifier circuit.

5. The venting device according to claim 3, characterized in that, The bus voltage detection module employs a second differential amplifier circuit; In this circuit, the inverting input terminal of the second differential amplifier circuit serves as the first input terminal of the bus voltage detection module, the non-inverting input terminal of the second differential amplifier circuit serves as the second input terminal of the bus voltage detection module, the output terminal of the second differential amplifier circuit serves as the output terminal of the bus voltage detection module, and the feedback resistance of the second differential amplifier circuit is less than the input resistance of the inverting input terminal of the second differential amplifier circuit.

6. The venting device according to claim 2, characterized in that, The detection unit includes a bus voltage detection module; The first input terminal of the bus voltage detection module is connected to the positive bus of the energy storage converter, the second input terminal of the bus voltage detection module is connected to the negative bus of the energy storage converter, and the output terminal of the bus voltage detection module serves as the output terminal of the detection unit. The bus voltage of the energy storage converter is output to the delay module as the first detection signal, and output to the comparison module as the second detection signal.

7. The venting device according to claim 1, characterized in that, The comparison module employs a hysteresis comparator. The input terminal of the hysteresis comparator serves as the input terminal of the comparison module, and the output terminal of the hysteresis comparator serves as the output terminal of the comparison module.

8. The venting device according to claim 1, characterized in that, The delay module employs a low-pass filter circuit; The input terminal of the low-pass filter circuit serves as the input terminal of the delay module, and the output terminal of the low-pass filter circuit serves as the output terminal of the delay module.

9. The venting device according to any one of claims 1 to 8, characterized in that, The energy discharge unit includes a switch module and a discharge resistor connected in series; The control terminal of the switch module serves as the control terminal of the energy discharge unit, and is used to receive the control signal, which is used to control the switch module to close or open.

10. An energy storage system, characterized in that, include: Energy storage converter, energy storage battery, and discharge device as described in any one of claims 1 to 9.

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