Bypass driving circuit, energy storage module and direct current energy storage system

Abstract

The invention relates to the technical field of direct-current energy storage systems, and discloses a bypass driving circuit, an energy storage module and a direct-current energy storage system.In the bypass driving circuit, a 24V power supply monitoring circuit is used for monitoring the power supply state of a 24V power supply in real time; the two PWM drive circuits are electrically connected with the two full-control semiconductor devices in the half-bridge circuit respectively and used for driving the two full-control semiconductor devices to be switched on and switched off; the fault feedback and direct connection prevention circuit is used for feeding back fault signals and preventing direct connection; the power conversion circuit is used for converting an external power supply and supplying power to the bypass driving circuit; and the MCU minimum system circuit is used for sending pulse control signals to the two paths of PWM drive circuits based on a 24V power supply state and a feedback fault signal to drive the two full-control semiconductor devices to be switched on and switched off. The fault battery pack can be bypassed in time, the cost is saved, the response is quick, the fault rate of the direct-current energy storage system is greatly reduced, and stable and reliable operation of the direct-current energy storage system is facilitated.

Description

Technical Field

[0001] The present invention relates to the technical field of direct current energy storage systems, and in particular to a bypass drive circuit, an energy storage module and a direct current energy storage system. Background Art

[0002] A DC energy storage system is a system that stores electrical energy in a DC energy storage device and can release energy when needed. Its main components include: energy storage modules, power electronic converters, control systems, monitoring and protection systems, etc. At present, DC energy storage systems are prone to power outages or "black module" failures of individual energy storage modules, which can cause the energy storage modules to fail to work properly and reduce the capacity of the energy storage system. In severe cases, the system may trip due to the protection mechanism, affecting the stability and reliability of the system operation.

[0003] Chinese patent CN 116960901 A discloses a DC / DC submodule bypass switch trigger circuit and detection circuit, including a programmable chip FPGA, a push-pull circuit and a thyristor; after the FPGA receives the bypass trigger high-level command issued by the valve layer controller, it converts it into a periodic pulse signal through the bypass module, and the periodic pulse signal enters the push-pull circuit, outputs a driving current, and realizes the control of the thyristor gate; the patent is based on the thyristor drive circuit scheme to realize the half-bridge circuit, and is also equipped with a high-reliability DC / DC submodule, which has a complex structure and high cost. Chinese patent CN206575326 U discloses a bypass circuit, which is based on a fully controlled electronic switch composed of IGBTs in series. This switch is arranged at the H-bridge port, which can solve the bypass demand of the H-bridge, but cannot solve the problem that the cascaded H-bridge cannot be bypassed due to power failure of the power supply and "black module" failure.

[0004] In summary, the bypass circuit and energy storage system disclosed in the prior art still have the problems of complex structure and inability to handle power outages and "black module" failures in a timely manner, which is not conducive to the stable and reliable operation of the DC energy storage system. Therefore, technical personnel in this field need to further improve and innovate the technology. Summary of the invention

[0005] The purpose of the present invention is to provide a bypass drive circuit, an energy storage module and a DC energy storage system, which have a simple structure and are easy to control. In the event of power failure or a "black module" failure, the faulty battery pack can be bypassed in time, thereby saving costs and responding quickly, greatly reducing the failure rate of the DC energy storage system, and facilitating the stable and reliable operation of the DC energy storage system.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] A bypass drive circuit, the bypass drive circuit is connected to a battery pack through a half-bridge circuit, the bypass drive circuit includes an MCU minimum system circuit and a 24V power supply monitoring circuit electrically connected to the MCU minimum system circuit, a 2-way PWM drive circuit, a fault feedback and anti-through circuit and a power conversion circuit;

[0008] The 24V power supply monitoring circuit is used to monitor the 24V power supply status in real time;

[0009] The two PWM drive circuits are respectively a half-bridge upper tube drive circuit and a half-bridge lower tube drive circuit, which are respectively electrically connected to two fully-controlled semiconductor devices in the half-bridge circuit, and are used to drive the two fully-controlled semiconductor devices to be turned on and off;

[0010] The fault feedback and direct-through prevention circuit comprises a fault feedback circuit and a direct-through prevention circuit, which are used for feedback of fault signals and direct-through prevention respectively;

[0011] The power conversion circuit is used to convert external power to supply power to the bypass drive circuit;

[0012] The MCU minimum system circuit is used to send pulse control signals to two PWM drive circuits based on the 24V power supply status and feedback fault signals, so as to drive the two fully controlled semiconductor devices to turn on and off.

[0013] Further, the 24V power supply monitoring circuit includes resistors R1, R2, R3, R4, R5, R6, R7, capacitors C1, C2, and optocouplers U1 and U2; the resistors R1 and R2 are connected in series and are respectively connected to the positive and negative electrodes of the 24V power supply, and the common ends of the resistors R1 and R2 are respectively connected to one end of the capacitor C1, one end of the resistor R4, and one end of the resistor R3; the other end of the resistor R4 is connected to the first pin of the optocoupler U1, the other end of the resistor R3 is connected to the optocoupler U2, and the optocoupler U2 is connected to the fault feedback circuit; the second pin of the optocoupler U1 and the other end of the capacitor C1 are respectively connected to the negative electrode of the 24v power supply; the fourth pin of the optocoupler U1 is respectively connected to one end of the resistor R5 and one end of the resistor R6, and the other end of the resistor R6 and one end of the capacitor C2 are connected to the half-bridge lower tube drive circuit; the other end of the resistor R5 is connected to the positive electrode of the 20V power supply, and the third pin of the optocoupler U1 and the other end of the capacitor C2 are respectively connected to the negative electrode of the 20V power supply.

[0014] Furthermore, the two fully-controlled semiconductor devices are respectively a fully-controlled semiconductor device Q1 and a fully-controlled semiconductor device Q2, the fully-controlled semiconductor device Q1 is connected to the positive electrode of the battery pack, and the fully-controlled semiconductor device Q2 is connected to the negative electrode of the battery pack;

[0015] The half-bridge upper tube driving circuit includes a resistor R12, an optical coupler U4, a push-pull circuit 1, and a resistor Rg1 which are electrically connected in sequence, the resistor R12 is connected to the MCU minimum system circuit, and the resistor Rg1 is connected to the fully controlled semiconductor device Q1;

[0016] The half-bridge lower tube driving circuit includes a resistor R8, an optocoupler U5, a diode D2, a push-pull circuit 2, and a resistor Rg2 which are electrically connected in sequence. The resistor R8 is connected to the MCU minimum system circuit, and the resistor Rg2 is connected to the fully controlled semiconductor device Q2. The base of the push-pull circuit 2 is connected to the 24V power supply monitoring circuit through a diode D1.

[0017] Furthermore, the fault feedback circuit includes a resistor R7, one end of which is connected to the MCU minimum system circuit, and the other end is connected to the 24V power supply monitoring circuit, and the connection intersection between the resistor R7 and the 24V power supply monitoring circuit is connected to a 3.3V power supply, and the 3.3V power supply is connected to the MCU minimum system circuit.

[0018] Furthermore, the anti-straight-through circuit includes a diode D3, a resistor R9, an optocoupler U3, a resistor R10, a resistor R11, a capacitor C3, and a diode D4. The MCU minimum system is connected to the anode of the diode D3, the cathode of the diode D3 is connected to one end of the resistor R9, the other end of the resistor R9 is connected to the first pin of the optocoupler U3, the fourth pin of the optocoupler U3 is respectively connected to one end of the resistor R10 and one end of the resistor R11, and the other end of the resistor R10 is respectively connected to one end of the capacitor C3 and the anode of the diode D4; the other end of the resistor R11 is connected to the positive electrode of the 20V_B power supply, the third pin of the optocoupler U3 and the other end of the capacitor C3 are respectively connected to the negative electrode of the 20V_B power supply; the cathode of the diode D4 is connected to the half-bridge lower tube drive circuit.

[0019] Furthermore, the power conversion circuit is provided with two groups, and the two groups of power conversion circuits use different voltages and powers. One group is from an external 24V power supply through electrical isolation to output multiple power supplies, including 20V power supply and 3.3V power supply, and the other group is from an external 12V power supply through electrical isolation to output a single power supply, which is a 20V power supply.

[0020] Furthermore, the MCU minimum system circuit is used to send a pulse control signal to the two-way PWM drive circuit based on the 24V power supply status and the feedback fault signal to drive the two fully controlled semiconductor devices to turn on and off, specifically including:

[0021] The MCU minimum system circuit receives a 24V power failure signal or a "black module" fault signal, controls the half-bridge lower tube drive circuit to output a high-level signal, so that the fully-controlled semiconductor device Q2 is turned on, and the battery pack is bypassed by the fully-controlled semiconductor device Q2.

[0022] The present invention also provides an energy storage module, including a battery pack, a half-bridge circuit and the above-mentioned bypass drive circuit, wherein the half-bridge circuit includes two fully-controlled semiconductor devices, the two fully-controlled semiconductor devices are connected in series, and a half-bridge midpoint is formed between the two fully-controlled semiconductor devices; the two fully-controlled semiconductor devices are respectively connected to the positive electrode and the negative electrode of the battery pack, and a capacitor C0 is also connected in parallel at both ends of the battery pack.

[0023] The present invention also provides a DC energy storage system, comprising a plurality of DC chain energy storage units arranged in parallel, each of the DC chain energy storage units comprising a plurality of the above energy storage modules, and the plurality of energy storage modules are cascaded and sequentially connected to a reactor and a DC switch.

[0024] Furthermore, in each of the DC chain energy storage units, the midpoint of the half bridge of the first energy storage module is connected to the reactor and the DC switch in sequence, the DC switch is connected to the DC positive terminal DC+, the negative pole of the first energy storage module is connected to the midpoint of the half bridge of the second energy storage module, the negative pole of the second energy storage module is connected to the midpoint of the half bridge of the third energy storage module, and so on, and the negative pole of the last energy storage module is connected to the DC negative terminal DC-.

[0025] Compared with the prior art, the bypass drive circuit, energy storage module and DC energy storage system provided by the present invention have the following technical effects:

[0026] (1) The bypass drive circuit provided by the present invention can timely collect the 4V power supply status of the MCU minimum system circuit, and timely send a pulse control signal to the PWM drive circuit to drive the two fully controlled semiconductor devices to be turned on and off. When the 24V power supply is off or a "black module" fails, it is beneficial to quickly bypass the faulty battery pack; and the half-bridge circuit composed of two controlled semiconductor devices can realize direct on-off control without the need for an external electronic or mechanical bypass switch; in addition, the anti-straight-through function can be realized through fault feedback and an anti-straight-through circuit. It can be seen that the bypass drive circuit uses a small amount of passive devices to realize the automatic bypass function. After any battery pack failure or internal failure of the energy storage module, the bypass or exit will be carried out, and the DC energy storage system will not fail and shut down, which greatly reduces the failure rate of the DC energy storage system, thereby improving the operation reliability of the DC energy storage system.

[0027] (2) The energy storage module provided by the present invention includes the above-mentioned bypass drive circuit. By adding a small amount of devices, the energy storage module based on the half-bridge circuit can be reused and turned on the fully controlled semiconductor device Q2 to bypass the energy storage module when the power supply is off or the "black module". The DC energy storage system will not shut down due to faults, which greatly reduces the failure rate of the DC energy storage system and improves the reliability of the DC energy storage system. In addition, the number of power devices in the energy storage module has not increased, and the technical solution has certain economic advantages.

[0028] (3) The DC energy storage system provided by the present invention is also provided with a reactor and a DC switching device, so that multiple groups of DC chain energy storage units can be easily connected in parallel, and the power expansion and capacity expansion of the energy storage system can be conveniently realized while isolating the faulty battery pack, thereby improving the operating reliability of the DC energy storage system.

[0029] In summary, the bypass drive circuit, energy storage module and DC energy storage system described in the present invention can easily realize the voltage boost of the DC energy storage system, expand the application scenarios of the DC energy storage system, and greatly improve the operational reliability of the DC energy storage system. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0031] Figure 1 It is a control principle structure block diagram of the bypass drive circuit of the present invention;

[0032] Figure 2 Schematic diagram of the circuit structure of the bypass driving circuit of the present invention;

[0033] Figure 3 It is a signal logic diagram of the power failure bypass of the present invention;

[0034] Figure 4 The signal logic diagram of the "black module" bypass of the present invention;

[0035] Figure 5 A hardware topology diagram of a single DC chain energy storage unit of the present invention;

[0036] Figure 6 The hardware topology diagram of the DC energy storage system of the present invention;

[0037] Figure 7 This is a schematic diagram of the structure of the optical couplers U1, U2, and U3 according to an embodiment of the present invention;

[0038] Figure 8Schematic diagram of the structure of the optocouplers U4 and U5 according to an embodiment of the present invention. DETAILED DESCRIPTION

[0039] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] The purpose of the present invention is to provide a bypass drive circuit, an energy storage module and a DC energy storage system. According to the circuit topology and application scenario, the bypass drive circuit includes multiple optoelectronic isolation devices, resistors, capacitors and a low-power power supply (12V / 1W). It can monitor the operating status of the energy storage module when the 24V power supply is off or the "black module" (or 3.3V power off) is abnormal, and open the semiconductor switch device Q2 in a fault state, so that the energy storage module is automatically bypassed, ensuring the normal operation of the DC energy storage system, thereby improving the reliability of the energy storage system.

[0041] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0042] Example 1

[0043] like Figure 1-Figure 3 As shown, the bypass drive circuit provided by the present invention is connected to the battery pack through a half-bridge circuit. The battery pack of the present invention includes a plurality of battery cells connected in series.

[0044] The bypass drive circuit includes an MCU minimum system circuit and a 24V power supply monitoring circuit electrically connected to the MCU minimum system circuit, a 2-way PWM drive circuit, a fault feedback and anti-through circuit, and a power conversion circuit;

[0045] The 24V power supply monitoring circuit is used to monitor the 24V power supply status in real time;

[0046] The two PWM drive circuits are respectively a half-bridge upper tube drive circuit and a half-bridge lower tube drive circuit, which are respectively electrically connected to two fully-controlled semiconductor devices in the half-bridge circuit, and are used to drive the two fully-controlled semiconductor devices to be turned on and off;

[0047] The fault feedback and direct-through prevention circuit comprises a fault feedback circuit and a direct-through prevention circuit, which are used for feedback of fault signals and direct-through prevention respectively;

[0048] The power conversion circuit is used to convert external power to supply power to the bypass drive circuit;

[0049] The MCU minimum system circuit is used to send pulse control signals to two PWM drive circuits based on the 24V power supply status and feedback fault signals, so as to drive the two fully controlled semiconductor devices to turn on and off.

[0050] In the embodiment of the present invention, the specific design of the bypass driving circuit is as follows:

[0051] (1) 24V power supply monitoring circuit

[0052] Specifically, the 24V power supply monitoring circuit includes resistors R1, R2, R3, R4, R5, R6, and R7, capacitors C1 and C2, and optocouplers U1 and U2; the resistors R1 and R2 are connected in series and are respectively connected to the positive and negative electrodes of the 24V power supply, and the common ends of the resistors R1 and R2 are respectively connected to one end of the capacitor C1, one end of the resistor R4, and one end of the resistor R3; the other end of the resistor R4 is connected to the first pin of the optocoupler U1, the other end of the resistor R3 is connected to the optocoupler U2, and the optocoupler U2 is connected to the fault feedback circuit; the second pin of the optocoupler U1 and the other end of the capacitor C1 are respectively connected to the negative electrode of the 24v power supply; the fourth pin of the optocoupler U1 is respectively connected to one end of the resistor R5 and one end of the resistor R6, and the other end of the resistor R6 and one end of the capacitor C2 are connected to the half-bridge lower tube drive circuit; the other end of the resistor R5 is connected to the positive electrode of the 20V power supply, and the third pin of the optocoupler U1 and the other end of the capacitor C2 are respectively connected to the negative electrode of the 20V power supply.

[0053] The other end of the resistor R3 is connected to the first pin of the optocoupler U2, the fourth pin of the optocoupler U2 is connected to the 3.3V power supply and the resistor R7 respectively, and the third pin of the optocoupler U2 is grounded. The other end of the resistor R6 and one end of the capacitor C2 are connected to the anode of the diode D1, and the cathode of the diode D1 is connected to the base of the push-pull circuit 2, that is, the common end connected to Q5, Q6, D2, and D4.

[0054] The 24V power supply monitoring circuit can realize the 24V power supply monitoring on the common side of the optocouplers U1 and U2. If the 24V power supply is powered off, the optocoupler U1 outputs a high signal, the driving level of the fully-controlled semiconductor device Q2 is set high, and the optocoupler U2 outputs a high level, and the MCU minimum system circuit receives the 24V power supply fault information.

[0055] (2) 2-way PWM drive circuit

[0056] Specifically, the two fully-controlled semiconductor devices are respectively a fully-controlled semiconductor device Q1 and a fully-controlled semiconductor device Q2, the fully-controlled semiconductor device Q1 is connected to the positive electrode of the battery pack, and the fully-controlled semiconductor device Q2 is connected to the negative electrode of the battery pack; for example, the fully-controlled semiconductor device Q1 and the fully-controlled semiconductor device Q2 are insulated-gate bipolar transistors (IGBT) or MOSFETs;

[0057] The half-bridge upper tube driving circuit includes a resistor R12, an optical coupler U4, a push-pull circuit 1, and a resistor Rg1 which are electrically connected in sequence, the resistor R12 is connected to the MCU minimum system circuit, and the resistor Rg1 is connected to the fully controlled semiconductor device Q1;

[0058] The half-bridge lower tube driving circuit includes a resistor R8, an optocoupler U5, a diode D2, a push-pull circuit 2, and a resistor Rg2 which are electrically connected in sequence. The resistor R8 is connected to the MCU minimum system circuit, and the resistor Rg2 is connected to the fully controlled semiconductor device Q2. The base of the push-pull circuit 2 is connected to the 24V power supply monitoring circuit through a diode D1.

[0059] Among them, the push-pull circuit 1 includes semiconductor devices Q3 and Q4 connected in series, and the push-pull circuit 2 includes semiconductor devices Q5 and Q6 connected in series. For example, the semiconductor devices Q3 and Q5 are ordinary NPN transistors, and the semiconductor devices Q4 and Q6 mentioned above are ordinary PNP transistors.

[0060] In the half-bridge upper tube driving circuit, the MCU minimum system circuit is connected to one end of the resistor R12, the other end of the resistor R12 is connected to the second pin of the optocoupler U4, the 6th and 7th pins of the optocoupler U4 are connected to the base of the push-pull circuit one, the common point of the semiconductor device Q3 and the semiconductor device Q4 in the push-pull circuit one is connected in series to one end of the resistor Rg1, and the other end of the resistor Rg1 is connected to the gate level of the fully controlled semiconductor device Q1.

[0061] In the half-bridge lower tube driving circuit, the MCU minimum system circuit is connected to the resistor R8, the other end of the resistor R8 is connected to the second pin of the optocoupler U5, the 6th and 7th pins of the optocoupler U5 are connected to one end of the diode D2, the other end of the diode D2 is connected to the base of the push-pull circuit 2, the common point of the semiconductor device Q5 and the semiconductor device Q6 in the push-pull circuit 2 is connected to one end of the resistor Rg2, and the other end of the resistor Rg2 is connected to the gate level of the fully controlled semiconductor device Q2. The base of the push-pull circuit 2 is also connected to the cathode of the diode D1 and the cathode of the diode D4.

[0062] The signal output by the MCU minimum system circuit to the half-bridge upper tube drive circuit is PWM_A, and the signal output to the half-bridge lower tube drive circuit is PWM_B. If PWM_A is high, the optocoupler U4 outputs a high level, and the drive level of the fully controlled semiconductor device Q1 is high, and vice versa; if PWM_B is high, the optocoupler U5 outputs a high level, and the drive level of the fully controlled semiconductor device Q2 is high, and vice versa.

[0063] (3) Fault feedback and anti-shoot-through circuit

[0064] The fault feedback circuit includes a resistor R7, one end of which is connected to the MCU minimum system circuit, and the other end is connected to the fourth pin of the optocoupler U2 in the 24V power supply monitoring circuit, and the connection intersection between the resistor R7 and the 24V power supply monitoring circuit is connected to a 3.3V power supply, and the 3.3V power supply is connected to the MCU minimum system circuit.

[0065] The anti-straight-through circuit includes a diode D3, a resistor R9, an optocoupler U3, a resistor R10, a resistor R11, a capacitor C3, and a diode D4. The MCU minimum system is connected to the anode of the diode D3, the cathode of the diode D3 is connected to one end of the resistor R9, the other end of the resistor R9 is connected to the first pin of the optocoupler U3, the fourth pin of the optocoupler U3 is respectively connected to one end of the resistor R10 and one end of the resistor R11, and the other end of the resistor R10 is respectively connected to one end of the capacitor C3 and the anode of the diode D4; the other end of the resistor R11 is connected to the positive electrode of the 20V_B power supply, and the third pin of the optocoupler U3 and the other end of the capacitor C3 are respectively connected to the negative electrode of the 20V_B power supply; the cathode of the diode D4 is connected to the half-bridge lower tube drive circuit, specifically, connected between the cathode of the diode D2 and the base of the push-pull circuit 2.

[0066] If the 24V power supply is powered off, the MCU minimum system circuit prohibits PWM and sends out a FAULT_UV low signal at the same time. The optocoupler U3 outputs a high signal, and the drive level of the fully controlled semiconductor device Q2 is high.

[0067] (4) Power conversion circuit

[0068] The power conversion circuit is provided with two groups, and the two groups of power conversion circuits use different voltages and powers. One group is a multi-channel power supply output by an external 24V power supply through electrical isolation, including: 20V_A, 20V_B, 3.3V; the other group is a single-channel power supply output by an external 12V through electrical isolation: 20V_B. Among them, 20V_A can be used as a driving power supply for the fully controlled semiconductor device Q1, and 20V_B can be used as a driving power supply for the fully controlled semiconductor device Q2. The external 12V power supply is used as a backup power supply after the 24V power supply is powered off. The two external power supplies can improve the reliability of the continuous operation of the circuit, module and energy storage system.

[0069] The power conversion circuit is a circuit used to convert one form of electrical energy into another form of electrical energy. Common power conversion circuits include DC / DC converters, DC / AC inverters, AC / DC rectifiers, etc. The DC / DC converter used in the embodiment of the present invention converts a DC voltage from one level to another level. The power conversion circuit is not an improved solution of the present invention and can be implemented with reference to the prior art. The detailed circuit is not described here.

[0070] (5) MCU minimum system circuit

[0071] The MCU minimum system circuit includes some common DSP, FPGA, ARM and other controllers and minimum circuits, which are not limited here.

[0072] The MCU minimum system circuit is used to send a pulse control signal to the two-way PWM drive circuit based on the 24V power supply status and the feedback fault signal to drive the two fully controlled semiconductor devices to turn on and off, specifically including:

[0073] The MCU minimum system circuit receives a 24V power failure signal or a "black module" fault signal, controls the half-bridge lower tube drive circuit to output a high-level signal, so that the fully-controlled semiconductor device Q2 is turned on, and the battery pack is bypassed by the fully-controlled semiconductor device Q2.

[0074] The working principle of the bypass driving circuit provided by the present invention is as follows:

[0075] 1. Working principle of power failure self-bypass:

[0076] like Figure 3 As shown, the 24V power supply monitoring circuit monitors the 24V power supply status in real time. After the 24V power supply is powered off, the secondary side of the optocoupler U2 outputs a high signal -FAULT_UV (because 3.3V has a small amount of capacitors, 3.3V is powered off slower than 24V, so U2 can output a high signal). The MCU minimum system circuit detects the high signal -FAULT_UV in real time, and can block PWM_A (low), PWM_B signal (high), PWM_B through the resistor R8 makes the internal light-emitting diode of the optocoupler U5 always bright, and the secondary side of the optocoupler U5 outputs a high signal, through the diode D2 to turn on the transistor Q5, thereby turning on the fully controlled semiconductor device Q2, so that the battery pack is bypassed by the fully controlled semiconductor device Q2. In addition, after the 24V power supply is powered off, the secondary side of the optocoupler U1 outputs a high signal, and the high signal turns on the transistor Q5 through the resistor R6 and the diode D1, thereby turning on the fully controlled semiconductor device Q2, so that the module is bypassed by Q2.

[0077] 2. Working principle of "black module" self-bypass:

[0078] like Figure 4As shown in the figure, the reasons why the energy storage module may cause a "black module" are: 1) the MCU minimum system circuit power supply -3.3V power failure; 2) the MCU minimum system circuit itself has a fault that cannot be self-recovered or operated. If a "black module" fault occurs, the FAULT_EN signal actively sent by the MCU minimum system circuit is set low, and the secondary side of the optocoupler U3 outputs a high signal. The high signal turns on the transistor Q5 through the resistor R10 and the diode D4, thereby turning on the fully controlled semiconductor device Q2, so that the module is bypassed by the fully controlled semiconductor device Q2.

[0079] 3. Active bypass process of energy storage module:

[0080] If the power supply of the energy storage module is not cut off and there is no "black module", if the battery pack fails, such as overcharge, over-discharge, over-temperature, over-voltage, under-voltage, etc., or an over-temperature failure occurs inside the energy storage module, the energy storage module needs to be bypassed or kicked out, and the bypass drive circuit can be used to turn on the fully controlled semiconductor device Q2, so that the energy storage module is bypassed by the fully controlled semiconductor device Q2. The DC energy storage system can remove the faulty energy storage module without affecting the normal operation of the entire energy storage system, greatly reducing the failure rate of the DC energy storage system, thereby improving the reliability of the DC energy storage system.

[0081] The specific process is as follows: the MCU minimum system circuit blocks PWM_A (low), PWM_B signal (high), PWM_B makes the internal light-emitting diode of the optocoupler U5 always light up through the resistor R8, and the secondary side of the optocoupler U5 outputs a high signal, which turns on the transistor Q5 through the diode D2, thereby turning on the fully controlled semiconductor device Q2, so that the energy storage module is bypassed by the fully controlled semiconductor device Q2. In addition, after the 24V power supply is powered off, the secondary side of the optocoupler U1 outputs a high signal, and the high signal turns on the transistor Q5 through the resistor R6 and the diode D1, thereby turning on the fully controlled semiconductor device Q2, so that the energy storage module is bypassed by the fully controlled semiconductor device Q2.

[0082] In the above scheme, the optocouplers U1, U2, and U3 use 4 pins and the structure is as follows: Figure 7 As shown, the optocouplers U4 and U5 use 8 pins and have the following structure: Figure 8 shown.

[0083] Among them, the optocoupler U1 is used to realize power failure detection; the optocoupler U2 and the optocoupler U3 are used to generate different bypass drive enable signals;

[0084] Optocouplers U1, U2, U3, U4, and U5 are all conventional optocoupler structures in the art and can be selected according to actual needs, so they will not be described in detail here.

[0085] The bypass drive circuit design provided by the present invention can realize the automatic bypass function by using a small amount of passive devices, and can bypass or exit after any battery pack failure or internal failure of the energy storage module. The DC energy storage system will not shut down due to failure, which greatly reduces the failure rate of the DC energy storage system, thereby improving the operational reliability of the DC energy storage system.

[0086] Example 2

[0087] The present invention also provides an energy storage module, including a battery pack, a half-bridge circuit and the above-mentioned bypass drive circuit, wherein the half-bridge circuit includes two fully-controlled semiconductor devices, the two fully-controlled semiconductor devices are connected in series, and a half-bridge midpoint is formed between the two fully-controlled semiconductor devices; the two fully-controlled semiconductor devices are respectively connected to the positive electrode and the negative electrode of the battery pack, and a capacitor C0 is also connected in parallel at both ends of the battery pack, and the capacitor C0 is located between the battery pack and the half-bridge circuit.

[0088] The half-bridge circuit is composed of a fully controlled semiconductor device Q1 and a fully controlled semiconductor device Q2 connected in series to form a three-port switch unit, the positive end of the three-port switch unit (the drain of the Q1 tube) is connected to the positive end of the capacitor C0, and the negative end of the three-port switch unit (the source of the Q2 tube) is connected to the negative end of the capacitor C0. The positive end of the capacitor C0 is connected in parallel with the positive end of the battery pack, and the negative end of the capacitor C0 is connected in parallel with the negative end of the battery pack.

[0089] The half-bridge circuit is connected in parallel with the battery pack. The half-bridge circuit can effectively adjust the charge and discharge current and power of the battery pack by controlling the on / off state and on-time of the fully-controlled semiconductor device Q1, thereby achieving balanced control of the state of charge in the battery pack.

[0090] The D pole (drain) of the fully controlled semiconductor device Q1 is connected to the positive pole (BAT11+) of the battery pack, the S pole (source) of the fully controlled semiconductor device Q2 is connected to the negative pole (BAT11-) of the battery pack, and the capacitor C0 is connected in parallel at both ends of the battery pack. The midpoint M+ of the half-bridge circuit and the negative pole (BAT11-) of the battery are led out, and the above is regarded as a complete energy storage module.

[0091] When the energy storage module is used in cascade, the bypass drive circuit inside the energy storage module can realize the full-control semiconductor device Q2 to realize the fault exit of the energy storage module when the power is off or the "black module" fails, without the need for additional configuration of electronic or mechanical bypass switches and related circuits.

[0092] Example 3

[0093] like Figure 5-Figure 6 As shown, the present invention also provides a DC energy storage system, including a plurality of DC chain energy storage units arranged in parallel, each of the DC chain energy storage units includes a plurality of the above-mentioned energy storage modules, and the plurality of energy storage modules are cascaded and connected in sequence to a reactor and a DC switch.

[0094] The midpoint of the half bridge of the first energy storage module is connected to one end of the reactor L1, the other end of the reactor L1 is connected to one end of the DC switch K1, the other end of the DC switch K1 is connected to the DC positive end (DC+), the battery negative pole (BAT11-) of the first energy storage module is connected to the midpoint of the half bridge of the second energy storage module, the battery negative pole (BAT12-) of the second energy storage module is connected to the midpoint of the half bridge of the third energy storage module, and so on, until the battery negative pole (BAT1n-) of the nth energy storage module is connected to the DC negative end (DC-), and the above constitutes a complete DC chain energy storage unit.

[0095] The working principle of the DC energy storage system provided by the present invention is as follows:

[0096] Charging process: The DC switch K1 of the first group of DC chain energy storage units is closed, and the DC side positive end (DC+) charges the battery pack BAT11 through the DC switch K1, the inductor L1 and the fully controlled semiconductor device Q1 of the first half-bridge circuit of the first group of DC chain energy storage units. The charging current flows out from BAT11-, and then the battery pack BAT12 is charged from the fully controlled semiconductor device Q1 of the second half-bridge circuit. The charging current flows out from BAT12-, and finally the charging current flows out from BAT1n-, and finally the charging current flows into the DC side negative end (DC-).

[0097] Discharge process: The DC switch K1 of the first group of DC chain energy storage units is closed, and the battery discharge current flows from the negative end of the DC side (DC-) into BAT1n. The fully controlled semiconductor device Q1 of the nth half-bridge circuit discharges the battery pack BAT1n, and the discharge current flows in from BAT1n. Then, the fully controlled semiconductor device Q1 of the n-1th half-bridge circuit discharges the battery pack BAT1(n-1), and the discharge current flows in from BAT1-. The discharge current flows out from BAT1, passes through the inductor L1 and the DC switch K1, and finally the discharge current flows into the negative and positive end of the DC side (DC+).

[0098] Among them, BAT11, BAT12...BAT1n, BAT21, BAT22...BAT2n, ..., BATn1, BATn2...BATnn can be energy storage battery packs, supercapacitor packs or other energy storage modules, such as lead-acid batteries, sodium-sulfur batteries, flow batteries and lithium-ion battery packs.

[0099] If a single energy storage module of a DC chain energy storage unit fails due to power supply or internal failure, the energy storage module can be bypassed through the bypass drive circuit inside the energy storage module. This does not affect the normal operation of the entire DC chain energy storage unit, greatly reduces the failure rate of the DC chain energy storage unit, and thus improves the reliability of the DC chain energy storage unit.

[0100] As described above, the DC positive terminal (DC+) and the DC negative terminal (DC-) of the multiple DC chain energy storage units are connected separately, which is very convenient for the expansion of DC power. If the DC chain energy storage unit fails due to power supply or internal failure of multiple energy storage modules, the DC switch Kn can be disconnected. The faulty DC chain energy storage unit is isolated, so as not to affect the normal operation of the entire DC energy storage system, which greatly reduces the failure rate of the DC energy storage system and improves the reliability of the DC energy storage system.

[0101] The present invention can solve the problems of low reliability and difficulty in expansion of existing DC energy storage systems by introducing passive devices. The passive devices such as resistors, capacitors, optocouplers, transistors, reactors and DC switches in the bypass drive circuit described in the present invention can bypass or exit the DC energy storage system when the battery pack fails, without affecting the normal operation of the DC energy storage system at all. The semiconductor devices and switch devices used are commonly used and conventional devices, and have a high economic advantage.

[0102] The design of the reactor and DC switching device of the DC energy storage system described in the present invention makes it easy to realize multiple groups of parallel connection of DC chain energy storage units, and can conveniently realize the power expansion and capacity expansion of the energy storage system while isolating the faulty battery pack, thereby improving the operational reliability of the DC energy storage system.

[0103] The present invention can solve the problems of low reliability and difficulty in expansion of the existing DC energy storage system by introducing fully controlled semiconductors and switch devices. The fully controlled semiconductor device Q2 and the DC switch in the half-bridge circuit described in the present invention have the ability to bypass or exit the DC energy storage system when the battery pack fails, without affecting the normal operation of the DC energy storage system at all.

[0104] The bypass drive circuit and energy storage module described in the present invention can easily realize voltage boosting of a DC energy storage system, expand the application scenarios of the DC energy storage system, and greatly improve the operational reliability of the DC energy storage system.

[0105] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A bypass drive circuit, characterized in that: The bypass drive circuit is connected to the battery pack through a half-bridge circuit, and the bypass drive circuit includes an MCU minimum system circuit and a 24V power supply monitoring circuit electrically connected to the MCU minimum system circuit, a 2-way PWM drive circuit, a fault feedback and anti-through circuit, and a power conversion circuit; The 24V power supply monitoring circuit is used to monitor the 24V power supply status in real time; The two PWM drive circuits are respectively a half-bridge upper tube drive circuit and a half-bridge lower tube drive circuit, which are respectively electrically connected to two fully-controlled semiconductor devices in the half-bridge circuit, and are used to drive the two fully-controlled semiconductor devices to be turned on and off; The fault feedback and direct-through prevention circuit comprises a fault feedback circuit and a direct-through prevention circuit, which are used for feedback of fault signals and direct-through prevention respectively; The power conversion circuit is used to convert external power to supply power to the bypass drive circuit; The MCU minimum system circuit is used to send pulse control signals to two PWM drive circuits based on the 24V power supply status and feedback fault signals, so as to drive the two fully controlled semiconductor devices to turn on and off.

2. The bypass driving circuit according to claim 1, characterized in that: The 24V power supply monitoring circuit includes resistors R1, R2, R3, R4, R5, R6, and R7, capacitors C1 and C2, and optocouplers U1 and U2; the resistors R1 and R2 are connected in series and are respectively connected to the positive and negative electrodes of the 24V power supply, and the common ends of the resistors R1 and R2 are respectively connected to one end of the capacitor C1, one end of the resistor R4, and one end of the resistor R3; the other end of the resistor R4 is connected to the first pin of the optocoupler U1, the other end of the resistor R3 is connected to the optocoupler U2, and the optocoupler U2 is connected to the fault feedback circuit; the second pin of the optocoupler U1 and the other end of the capacitor C1 are respectively connected to the negative electrode of the 24V power supply; the fourth pin of the optocoupler U1 is respectively connected to one end of the resistor R5 and one end of the resistor R6, and the other end of the resistor R6 and one end of the capacitor C2 are connected to the half-bridge lower tube driving circuit; the other end of the resistor R5 is connected to the positive electrode of the 20V power supply, and the third pin of the optocoupler U1 and the other end of the capacitor C2 are respectively connected to the negative electrode of the 20V power supply.

3. The bypass driving circuit according to claim 1, characterized in that: The two fully-controlled semiconductor devices are respectively a fully-controlled semiconductor device Q1 and a fully-controlled semiconductor device Q2, the fully-controlled semiconductor device Q1 is connected to the positive electrode of the battery pack, and the fully-controlled semiconductor device Q2 is connected to the negative electrode of the battery pack; The half-bridge upper tube driving circuit includes a resistor R12, an optical coupler U4, a push-pull circuit 1, and a resistor Rg1 which are electrically connected in sequence, the resistor R12 is connected to the MCU minimum system circuit, and the resistor Rg1 is connected to the fully controlled semiconductor device Q1; The half-bridge lower tube driving circuit includes a resistor R8, an optocoupler U5, a diode D2, a push-pull circuit 2, and a resistor Rg2 which are electrically connected in sequence. The resistor R8 is connected to the MCU minimum system circuit, and the resistor Rg2 is connected to the fully controlled semiconductor device Q2. The base of the push-pull circuit 2 is connected to the 24V power supply monitoring circuit through a diode D1.

4. The bypass driving circuit according to claim 1, characterized in that: The fault feedback circuit includes a resistor R7, one end of which is connected to the MCU minimum system circuit, and the other end is connected to the 24V power supply monitoring circuit, and the connection intersection between the resistor R7 and the 24V power supply monitoring circuit is connected to a 3.3V power supply, and the 3.3V power supply is connected to the MCU minimum system circuit.

5. The bypass driving circuit according to claim 1, characterized in that: The anti-straight-through circuit includes a diode D3, a resistor R9, an optocoupler U3, a resistor R10, a resistor R11, a capacitor C3, and a diode D4. The MCU minimum system is connected to the anode of the diode D3, the cathode of the diode D3 is connected to one end of the resistor R9, the other end of the resistor R9 is connected to the first pin of the optocoupler U3, the fourth pin of the optocoupler U3 is respectively connected to one end of the resistor R10 and one end of the resistor R11, and the other end of the resistor R10 is respectively connected to one end of the capacitor C3 and the anode of the diode D4; the other end of the resistor R11 is connected to the positive electrode of the 20V power supply, the third pin of the optocoupler U3 and the other end of the capacitor C3 are respectively connected to the negative electrode of the 20V power supply; the cathode of the diode D4 is connected to the half-bridge lower tube drive circuit.

6. The bypass driving circuit according to claim 1, characterized in that: The power conversion circuit is provided with two groups, and the two groups of power conversion circuits adopt different voltages and powers. One group is a multi-channel power supply output by an external 24V power supply through electrical isolation, including a 20V power supply and a 3.3V power supply; the other group is a single-channel power supply output by an external 12V power supply through electrical isolation, which is a 20V power supply.

7. The bypass driving circuit according to claim 3, characterized in that: The MCU minimum system circuit is used to send a pulse control signal to the two-way PWM drive circuit based on the 24V power supply status and the feedback fault signal to drive the two fully controlled semiconductor devices to turn on and off, specifically including: The MCU minimum system circuit receives a 24V power failure signal or a "black module" fault signal, controls the half-bridge lower tube drive circuit to output a high-level signal, so that the fully-controlled semiconductor device Q2 is turned on, and the battery pack is bypassed by the fully-controlled semiconductor device Q2.

8. An energy storage module, characterized in that: It includes a battery pack, a half-bridge circuit and the bypass drive circuit according to any one of claims 1 to 7, wherein the half-bridge circuit includes two fully-controlled semiconductor devices, the two fully-controlled semiconductor devices are connected in series, and a half-bridge midpoint is formed between the two fully-controlled semiconductor devices; the two fully-controlled semiconductor devices are respectively connected to the positive electrode and the negative electrode of the battery pack, and a capacitor C0 is also connected in parallel at both ends of the battery pack.

9. A DC energy storage system, characterized in that: It comprises a plurality of DC chain energy storage units arranged in parallel, each of the DC chain energy storage units comprises a plurality of energy storage modules according to claim 8, and the plurality of energy storage modules are cascaded and connected in sequence with a reactor and a DC switch.

10. The DC energy storage system according to claim 9, characterized in that: In each of the DC chain energy storage units, the midpoint of the half bridge of the first energy storage module is connected to the reactor and the DC switch in sequence, the DC switch is connected to the DC positive terminal DC+, the negative pole of the first energy storage module is connected to the midpoint of the half bridge of the second energy storage module, the negative pole of the second energy storage module is connected to the midpoint of the half bridge of the third energy storage module, and so on, the negative pole of the last energy storage module is connected to the DC negative terminal DC-.

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