A battery bidirectional equalization control method and control circuit

Abstract

This invention provides a bidirectional battery equalization control method and control circuit. The bidirectional switching circuit receives a control signal and controls the switch and rectifier to turn off based on the control signal. It also detects the transformer winding voltage and controls the switch and rectifier to turn on based on the control signal and the winding voltage. Alternatively, it can turn on the switch and rectifier after a delay without detecting the transformer winding voltage. In this invention, when the control signal is high, the switch and rectifier are turned off; when the control signal is low, the switch and rectifier are turned on by detecting fluctuations in the transformer winding voltage. Alternatively, the switch and rectifier can be turned on after a delay. This invention achieves bidirectional transmission using only a single signal isolation device, solving the problem of simultaneous conduction of the primary and secondary switches and rectifiers in existing technologies.

Description

Technical Field

[0001] This invention relates to the field of bidirectional battery equalization control, and particularly to a bidirectional battery equalization control method and control circuit. Background Technology

[0002] The battery energy storage industry is developing rapidly and its applications are becoming increasingly widespread. Due to factors such as battery materials and manufacturing processes, the voltage of individual cells in a battery pack may differ after charging or discharging. This can lead to reduced battery pack lifespan and safety issues caused by overcharging and discharging. Since batteries account for over 80% of the total cost, improving battery lifespan is equivalent to significantly reducing costs; therefore, battery balancing technology has become an essential means to improve battery lifespan.

[0003] Bidirectional equalization technology, simply put, charges the low-voltage battery and discharges the high-voltage battery, ultimately bringing all individual cells to a consistent operating state. The equalization module typically operates at a power of 5W to 15W, and existing technologies are generally as shown in Figure 1. Its key point is that the control signal CTL controls certain devices in the circuit to operate or deactivate, forming two flyback circuits for forward operation (charging) and reverse operation (discharging). In forward operation, the control signal CTL controls PWM controller 1 to operate, and the control signal CTL controls the synchronous rectifier controller to operate via an optocoupler, while PWM controller 2 is deactivated; correspondingly, MOSFET TR1 is the main switch, MOSFET TR2 is the synchronous rectifier, and diode D1 is not involved in operation. In reverse discharge, the control signal CTL controls PWM controller 1 to deactivate, and the control signal CTL controls the synchronous rectifier controller to deactivate via an optocoupler, while PWM controller 2 operates; correspondingly, MOSFET TR2 is the main switch, diode D1 is the freewheeling diode, and MOSFET TR1 is not involved in operation.

[0004] Regardless of the control method, the PWM controller will actively output a square wave signal to control the on / off state of the MOSFET. Figure 1 In a flyback circuit consisting of a transformer and MOSFETs TR1 and TR2, MOSFETs TR1 and TR2 are controlled by different PWM controllers. Therefore, MOSFETs TR1 and TR2 may conduct simultaneously. This is equivalent to the primary and secondary sides of the transformer being simultaneously connected to the input and output. The current flowing from the VIN+ terminal in this case is IIN = (V... IN+ N PS *V O ) / R 内阻 R 内阻 The resistance is the sum of the MOSFET's internal resistance and the circuit's internal resistance, typically less than 0.1Ω. Therefore, the current flowing through the MOSFET can be extremely large, potentially damaging the device. Thus, in practical applications, it is crucial to absolutely avoid situations where the primary and secondary PWM controllers operate simultaneously.

[0005] The basic control principle of a synchronous rectifier controller is that it only turns on the MOSFET when it detects a negative voltage in the body diode. Figure 1 In the main power circuit, if MOSFETs TR1 and TR2 are both connected to synchronous rectifier controllers instead of PWM controllers, even if the synchronous rectifier controllers on the primary and secondary sides operate simultaneously, it will not cause a reliability issue of simultaneous conduction. This is because when powered on, the synchronous rectifier controller waits for the negative voltage of the MOSFETs, but the MOSFETs are in the off state when powered on, so there is no current. This means that the synchronous rectifier controller will never output a square wave signal, the MOSFETs will always be in the off state, and the circuit will not work.

[0006] In industrial control applications, interference is often significant. If the protection circuitry is not properly implemented, it can cause random jitter in the control signal CTL. The control signal CTL controls the operation of the two PWM controllers on the primary and secondary sides. Since there is a certain delay in the start-up and shutdown of the PWM controllers, if the control signal CTL jitters, it can cause the two PWM controllers on the primary and secondary sides to operate simultaneously. There is a probability that MOSFETs TR1 and TR2 will conduct at the same time, ultimately leading to damage. Therefore, current control technology needs to be improved to address the reliability issues. Summary of the Invention

[0007] The purpose of this invention is to provide a bidirectional battery equalization control method and control circuit, which can solve the problem of simultaneous conduction of two power MOSFETs on the primary and secondary sides in the prior art.

[0008] The objective of this invention is achieved through the following technical solution:

[0009] On one hand, the present invention provides a battery bidirectional equalization control method, comprising the following steps:

[0010] S1. The first bidirectional switching circuit and signal isolation device receive external control signals;

[0011] S2. If the control signal is a positive working signal, the first bidirectional switching circuit detects the average working voltage of the first winding of the transformer. When the working voltage of the first winding does not have high-low transitions and is a stable high-level voltage, the first bidirectional switching circuit controls the first switch and rectifier to conduct through the first master controller; or, the first bidirectional switching circuit detects the edge signal of the first winding of the transformer. When a falling edge is received, the output port is kept at a low level, controlling the first switch and rectifier to not conduct. When the received voltage signal is kept at a high level, the output port outputs a high level, controlling the first switch and rectifier to conduct; the signal isolation device flips the control signal and outputs it to the second bidirectional switching circuit, then proceeds to S3;

[0012] If the control signal is a reverse working signal, the first bidirectional switching circuit controls the first switch and rectifier to turn off through the first master controller; the signal isolation device flips the control signal and outputs it to the second bidirectional switching circuit, and then switches to S4.

[0013] S3. The second bidirectional switching circuit controls the second switch and rectifier to turn off through the second master controller, and returns to S1.

[0014] S4. The second bidirectional switching circuit detects the average operating voltage of the second winding of the transformer. When the operating voltage of the second winding does not have high-low transitions and is a stable high-level voltage, the second bidirectional switching circuit controls the second switch and rectifier to conduct through the second main controller. Alternatively, the second bidirectional switching circuit detects the edge signal of the second winding of the transformer. When a falling edge is received, the output port is kept at a low level, controlling the second switch and rectifier to not conduct. When the received voltage signal is kept at a high level, the output port outputs a high level, controlling the second switch and rectifier to conduct. Return to S1.

[0015] On the other hand, the present invention provides a battery bidirectional equalization control circuit, including a transformer and a signal isolation device, and further including a first switch and rectifier, a first main controller and a first bidirectional switching circuit connected sequentially between the first winding of the transformer and one end of the signal isolation device, and a second switch and rectifier, a second main controller and a second bidirectional switching circuit connected sequentially between the second winding of the transformer and the other end of the signal isolation device.

[0016] The first bidirectional switching circuit receives a control signal at its input terminal, and controls the first switch and rectifier to turn off according to the control signal; it detects the average voltage signal of the first winding of the transformer, and controls the first switch and rectifier to turn on according to the control signal and whether there is a high-low transition in the average voltage signal of the first winding; or

[0017] The first bidirectional switching circuit detects the edge signal of the first winding of the transformer and controls the first switch and rectifier to turn on based on whether there is a falling edge in the edge signal of the first winding.

[0018] One end of the signal isolation device receives the control signal and, after transmission, outputs it from the other end of the signal isolation device to the second bidirectional switching circuit.

[0019] The second bidirectional switching circuit receives a control signal transmitted via a signal isolation device at its input terminal. Based on the control signal transmitted via the signal isolation device, it controls the second switch and rectifier to turn off. It also detects the average voltage signal of the second winding of the transformer and controls the second switch and rectifier to turn on based on the control signal transmitted via the signal isolation device and whether there is a high-low transition in the average voltage signal of the second winding. Alternatively, the second bidirectional switching circuit detects the edge signal of the second winding of the transformer and controls the second switch and rectifier to turn on based on whether there is a falling edge in the edge signal of the second winding.

[0020] Furthermore, the first or second master controller includes a PWM controller.

[0021] Furthermore, the first switch and rectifier device includes a first MOSFET TR1 and a first diode D1, and the second switch and rectifier device includes a second MOSFET TR2 and a second diode D2; the anode of the first diode D1 is connected to the source of the first MOSFET TR1, the anode of the second diode D2, and the source of the second MOSFET TR2; the cathode of the first diode D1 is connected to the drain of the first MOSFET TR1 and one end of the first winding; the cathode of the second diode D2 is connected to the drain of the second MOSFET TR2 and one end of the second winding; the gate of the first MOSFET TR1 is connected to the PWM controller in the first master controller, and the gate of the second MOSFET TR2 is connected to the PWM controller in the second master controller.

[0022] Furthermore, the first or second master controller includes a PWM controller and a synchronous rectifier controller connected in parallel.

[0023] Furthermore, the first switch and rectifier is a first MOSFET TR1, and the second switch and rectifier is a second MOSFET TR2; the source of the first MOSFET TR1 is connected to ground GND_P on one side of the first winding of the transformer, and the source of the second MOSFET TR2 is connected to ground GND_S on one side of the second winding of the transformer; the drain of the first MOSFET TR1 is connected to one end of the first winding; the drain of the second MOSFET TR2 is connected to one end of the second winding; the gate of the first MOSFET TR1 is connected to the first master controller, and the gate of the second MOSFET TR2 is connected to the second master controller.

[0024] Furthermore, the first or second bidirectional switching circuit includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a first comparator COMP1, a second comparator COMP2, a third comparator COMP3, a first capacitor C1, a first RS flip-flop RS1, a first NOT gate NOT1, and a first AND gate AND1; the inverting input terminal of the second comparator COMP2 serves as the input terminal of either the first or second bidirectional switching circuit; one end of the first resistor R1 is connected to one end of the first winding or one end of the second winding; the other end of the first resistor R1 is connected to one end of the second resistor R2 and the inverting input terminal of the third comparator COMP3; the non-inverting input terminal of the third comparator COMP3, the non-inverting input terminal of the second comparator COMP2, and the non-inverting input terminal of the first comparator COMP1 are respectively input to a reference voltage REF; the output of the third comparator COMP3... One end of the third resistor R3 is connected to one end of the first capacitor C1, one end of the fourth resistor R4, and the inverting input of the first comparator COMP1. The other ends of the second resistor R2, the first capacitor C1, and the fourth resistor R4 are connected to ground GND_P on the first winding side or ground GND_S on the second winding side. The output of the first comparator COMP1 is connected to the S terminal of the first RS flip-flop RS1. The output of the second comparator COMP2 is connected to one input of the first AND gate AND1 and the input of the first NOT gate NOT1. The output of the first NOT gate NOT1 is connected to the R terminal of the first RS flip-flop RS1. The Q terminal of the first RS flip-flop RS1 is connected to the other input of the first AND gate AND1. The output of the first AND gate AND1 outputs the PWM control signal PWM_EN to the PWM controller of the first master controller or the PWM controller of the second master controller.

[0025] Furthermore, the first or second bidirectional switching circuit includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a first comparator COMP1, a second comparator COMP2, a third comparator COMP3, a first capacitor C1, a first RS flip-flop RS1, a first NOT gate NOT1, and a first AND gate AND1; the inverting input terminal of the second comparator COMP2 serves as the input terminal of either the first or second bidirectional switching circuit; one end of the first resistor R1 is connected to one end of the first winding or one end of the second winding; the other end of the first resistor R1 is connected to one end of the second resistor R2 and the inverting input terminal of the third comparator COMP3; the non-inverting input terminal of the third comparator COMP3, the non-inverting input terminal of the second comparator COMP2, and the non-inverting input terminal of the first comparator COMP1 are respectively connected to a reference voltage REF; the output terminal of the third comparator COMP3 is connected to one end of the third resistor R3, and the other end of the third resistor R4 is connected to the reference voltage REF. Connect one end of the first capacitor C1, one end of the fourth resistor R4, and the inverting input of the first comparator COMP1; connect the other ends of the second resistor R2, the first capacitor C1, and the fourth resistor R4 to ground GND_P on the first winding side or ground GND_S on the second winding side; connect the output of the first comparator COMP1 to the S terminal of the first RS flip-flop RS1; connect the output of the second comparator COMP2 to one input of the first AND gate AND1 and the input of the first NOT gate NOT1; connect the output of the first NOT gate NOT1 to the R terminal of the first RS flip-flop RS1 and output the synchronous rectification control signal SR_EN to the synchronous rectification controller of the first master controller or the synchronous rectification controller of the second master controller; connect the Q terminal of the first RS flip-flop RS1 to the other input of the first AND gate AND1; output the first AND gate AND1 to output the PWM control signal PWM_EN to the PWM controller of the first master controller or the PWM controller of the second master controller.

[0026] Furthermore, the first or second bidirectional switching circuit includes a first resistor R1, a second resistor R2, a counter, a second comparator COMP2, a first RS flip-flop RS1, and a first AND gate AND1; the inverting input of the second comparator COMP2 serves as the input of either the first or second bidirectional switching circuit, and the non-inverting input of the second comparator COMP2 receives a reference voltage REF; one end of the first resistor R1 is connected to one end of the first winding or one end of the second winding; the other end of the first resistor R1 is connected to one end of the second resistor R2 and the reset input port RS of the counter; the other end of the second resistor R2 is connected to ground G on one side of the first winding. ND_P or GND_S on one side of the second winding; the clock input port CT of the counter inputs a set number of square wave signals CLK; the output terminal OUT of the counter is connected to the S terminal of the first RS flip-flop RS1; the output terminal of the second comparator COMP2 is connected to one input terminal of the first AND gate AND1 and the input terminal of the first NOT gate NOT1 respectively; the output terminal of the first NOT gate NOT1 is connected to the R terminal of the first RS flip-flop RS1; the Q terminal of the first RS flip-flop RS1 is connected to the other input terminal of the first AND gate AND1; the output terminal of the first AND gate AND1 outputs the PWM control signal PWM_EN to the PWM controller of the first master controller or the PWM controller of the second master controller.

[0027] Furthermore, the first or second bidirectional switching circuit includes a first resistor R1, a second resistor R2, a counter, a second comparator COMP2, a first RS flip-flop RS1, a first NOT gate NOT1, and a first AND gate AND1; the inverting input of the second comparator COMP2 serves as the input of either the first or second bidirectional switching circuit, and the non-inverting input of the second comparator COMP2 receives a reference voltage REF; one end of the first resistor R1 is connected to one end of the first winding or one end of the second winding; the other end of the first resistor R1 is connected to one end of the second resistor R2 and the reset input port RS of the counter; the other end of the second resistor R2 is connected to ground GND_P on one side of the first winding or ground GND_S on one side of the second winding. The clock input port CT of the counter receives a set number of square wave signals CLK; the output terminal OUT of the counter is connected to the S terminal of the first RS flip-flop RS1; the output terminal of the second comparator COMP2 is connected to one input terminal of the first AND gate AND1 and the input terminal of the first NOT gate NOT1; the output terminal of the first NOT gate NOT1 is connected to the R terminal of the first RS flip-flop RS1 and outputs a synchronous rectification control signal SR_EN to the synchronous rectification controller of the first master controller or the synchronous rectification controller of the second master controller; the Q terminal of the first RS flip-flop RS1 is connected to the other input terminal of the first AND gate AND1; the output terminal of the first AND gate AND1 outputs a PWM control signal PWM_EN to the PWM controller of the first master controller or the PWM controller of the second master controller.

[0028] Furthermore, when the control signal is a positive working signal, the first bidirectional switching circuit delays for a period of time before controlling the first switch and rectifier to turn on via the first master controller; when the control signal is a negative working signal, the second bidirectional switching circuit delays for a period of time before controlling the second switch and rectifier to turn on via the second master controller; the first bidirectional switching circuit or the second bidirectional switching circuit includes a fourth comparator COMP7, a fifth comparator COMP8, a fifth resistor R5, a first transistor Q1, and a second capacitor C2; the inverting input terminal of the fourth comparator COMP7 serves as the input terminal of the first bidirectional switching circuit or the second bidirectional switching circuit, and the positive input terminal of the fourth comparator COMP7... The reference voltage REF is input to the input terminal and the inverting input terminal of the fifth comparator COMP8; the output terminal of the fourth comparator COMP7 is connected to one end of the fifth resistor R5 and the base of the first transistor Q1; the other end of the fifth resistor R5 is connected to the emitter of the first transistor Q1, one end of the second capacitor C2 and the non-inverting input terminal of the fifth comparator COMP8; the collector of the first transistor Q1 and the other end of the second capacitor C2 are connected to ground GND_P on the first winding side or ground GND_S on the second winding side; the output terminal of the fifth comparator COMP8 outputs the PWM control signal PWM_EN to the PWM controller of the first master controller or the PWM controller of the second master controller.

[0029] Furthermore, when the control signal is a positive working signal, the first bidirectional switching circuit delays for a period of time before controlling the first switch and rectifier to turn on via the first master controller; when the control signal is a negative working signal, the second bidirectional switching circuit delays for a period of time before controlling the second switch and rectifier to turn on via the second master controller; the first bidirectional switching circuit or the second bidirectional switching circuit includes a fourth comparator COMP7, a fifth comparator COMP8, a fifth resistor R5, a first transistor Q1, a second capacitor C2, and a second NOT gate NOT2; the inverting input terminal of the fourth comparator COMP7 serves as the input terminal of the first bidirectional switching circuit or the second bidirectional switching circuit, and the positive input terminal of the fourth comparator COMP7 and... The inverting input of the fifth comparator COMP8 receives the reference voltage REF; the output of the fourth comparator COMP7 is connected to one end of the fifth resistor R5, the base of the first transistor Q1, and the input of the second NOT gate NOT2; the output of the second NOT gate NOT2 outputs the synchronous rectification control signal SR_EN to the synchronous rectification controller of the first master controller or the synchronous rectification controller of the second master controller; the collector of the first transistor Q1 and the other end of the second capacitor C2 are connected to the ground GND_P on the first winding side or the ground GND_S on the second winding side; the output of the fifth comparator COMP8 outputs the PWM control signal PWM_EN to the PWM controller of the first master controller or the PWM controller of the second master controller.

[0030] This invention discloses a bidirectional battery equalization control method and control circuit. When the control signal is high, the switch and rectifier are turned off. When the control signal is low, the system detects fluctuations in the transformer winding voltage to determine whether to turn on the switch and rectifier. Alternatively, the system may delay turning on the switch and rectifier for a period of time. This invention achieves bidirectional transmission using only a single signal isolation device, solving the problem of simultaneous conduction of the primary and secondary switches and rectifiers in existing technologies. Attached Figure Description

[0031] Figure 1 This is a block diagram of a prior art battery bidirectional equalization control circuit;

[0032] Figure 2 This is a block diagram of the battery bidirectional equalization control circuit of the present invention;

[0033] Figure 3 The waveform timing diagram is a block diagram of the battery bidirectional equalization control circuit of the present invention.

[0034] Figure 4 This is a block diagram of the battery bidirectional equalization control circuit according to Embodiment 1 of the present invention;

[0035] Figure 5This is one of the circuit schematics of the bidirectional switching circuit of the present invention;

[0036] Figure 6 This is a waveform timing diagram of the battery bidirectional equalization control circuit according to Embodiment 1 of the present invention;

[0037] Figure 7 A schematic diagram of a synchronous rectifier controller;

[0038] Figure 8 This is the second circuit schematic diagram of the bidirectional switching circuit of the present invention;

[0039] Figure 9 This is a block diagram of the battery bidirectional equalization control circuit according to Embodiment 3 of the present invention;

[0040] Figure 10 This is a block diagram of the battery bidirectional equalization control circuit according to Embodiment 4 of the present invention;

[0041] Figure 11 The third circuit diagram of the bidirectional switching circuit of the present invention;

[0042] Figure 12 The fourth circuit diagram of the bidirectional switching circuit of the present invention;

[0043] Figure 13 This is a waveform timing diagram of the battery bidirectional equalization control circuit in Embodiment 4 of the present invention;

[0044] Figure 14 This is a schematic diagram of a PWM controller. Detailed Implementation

[0045] The embodiments of this disclosure will now be described in detail with reference to the accompanying drawings.

[0046] The following specific examples illustrate the implementation of this disclosure. Those skilled in the art can easily understand other advantages and effects of this disclosure from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this disclosure, and not all of them. This disclosure can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this disclosure. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0047] Example 1

[0048] On one hand, a battery bidirectional equalization control method according to this embodiment includes the following steps:

[0049] S1. The first bidirectional switching circuit and signal isolation device receive external control signals;

[0050] S2. If the control signal is a positive working signal, the first bidirectional switching circuit detects the working voltage of the first winding of the transformer. When the working voltage of the first winding is a stable voltage, the first bidirectional switching circuit controls the first switch and rectifier to conduct through the first master controller; the signal isolation device flips the control signal and outputs it to the second bidirectional switching circuit, and then proceeds to S3.

[0051] If the control signal is a reverse working signal, the first bidirectional switching circuit controls the first switch and rectifier to turn off through the first master controller; the signal isolation device flips the control signal and outputs it to the second bidirectional switching circuit, and then switches to S4.

[0052] S3. The second bidirectional switching circuit controls the second switch and rectifier to turn off through the second master controller, and returns to S1.

[0053] S4. The second bidirectional switching circuit detects the operating voltage of the second winding of the transformer. When the operating voltage of the second winding is a stable voltage, the second bidirectional switching circuit controls the second switch and rectifier to conduct through the second main controller, and returns to S1.

[0054] The first and second bidirectional switching circuits couple the transformer winding voltage. When the transformer winding voltage is detected to be in a high-low transition state (i.e., a square wave signal), it indicates that the opposite switch and rectifier are still operating. The local PWM controller can only be controlled when the transformer winding voltage reaches a stable value (i.e., a high level). In this invention, the first or second winding can be a main power winding (primary or secondary winding) or an auxiliary winding.

[0055] The control signal CTL controls the battery bidirectional equalization control circuit to operate in either the forward or reverse direction. The control signal CTL can be high or low, indicating that the battery bidirectional equalization control circuit operates in the forward direction. For ease of description, this embodiment uses the case of CTL being low, indicating the battery bidirectional equalization control circuit is operating in the forward direction, but this does not imply that the scope of protection of this invention is limited to this.

[0056] Signal isolation devices, due to their inherent characteristics, typically experience a transmission delay. After receiving the control signal CTL, there is a delay before the output of the toggled control signal; this is determined by the device's inherent features. Of course, signal isolation devices without delay can also meet the requirements of this invention.

[0057] When switching between forward and reverse operation, switch and rectifier device 1 and switch and rectifier device 2 cannot be in switching mode simultaneously. Otherwise, both switches may be actively turned on, causing transformer T1 to be short-circuited and damaging the devices. However, when switch and rectifier device 1 and switch and rectifier device 2 are in rectification mode simultaneously, neither the primary nor secondary side will be actively turned on, preventing problems. This state is similar to a "dead zone." In actual operation, due to signal transmission and switching delays, there is a delay in the mode switching of the switch and rectifier devices, leading to the risk that the circuit topology may be in switching mode simultaneously. To ensure reliable forward and reverse switching, a certain dead zone must be maintained during the switching process, such as... Figure 3 As shown.

[0058] On the other hand, a battery bidirectional equalization control circuit in this embodiment is as follows: Figure 2 and Figure 4 As shown, it includes a transformer T1 and a signal isolation device, and also includes a first switch and rectifier 1, a first main controller 1 and a first bidirectional switching circuit 1 connected between the first winding of the transformer T1 and one end of the signal isolation device, as well as a second switch and rectifier 2, a second main controller 2 and a second bidirectional switching circuit 2 connected between the second winding of the transformer T1 and the other end of the signal isolation device.

[0059] The first bidirectional switching circuit 1 receives a control signal CTL at its input terminal and controls the first switch and rectifier 1 to turn off according to the control signal CTL; it detects the voltage signal of the first winding of transformer T1 and controls the first switch and rectifier 1 to turn on according to the control signal CTL and the voltage signal of the first winding.

[0060] One end of the signal isolator receives the control signal CTL and, after transmission, outputs it from the other end to the second bidirectional switching circuit 2. Transmitting the control signal CTL via the signal isolator essentially involves flipping the level of the control signal CTL.

[0061] The input terminal of the second bidirectional switching circuit 2 receives a control signal transmitted through a signal isolation device. Based on the control signal transmitted through the signal isolation device, it controls the second switch and rectifier 2 to turn off. It detects the voltage signal of the second winding of transformer T1 and controls the second switch and rectifier 2 to turn on based on the control signal after the flip and the voltage signal of the second winding.

[0062] In typical applications, batteries are connected to both ends of the two windings of transformer T1, such as... Figure 2 The battery consists of battery 1 and battery 2. When operating in the forward direction, the bidirectional battery equalization control circuit discharges battery 1 and charges battery 2; when operating in the reverse direction, the bidirectional battery equalization control circuit charges battery 1 and discharges battery 2.

[0063] The specific control process is as follows: When the control signal CTL is low, the bidirectional switching circuit 1 controls the switch and rectifier 1 to operate in switching mode through the main controller 1; the control signal CTL is transmitted to the other end of the transformer through the signal isolator, and the bidirectional switching circuit 2 controls the switch and rectifier 2 to operate in rectification mode through the main controller 2. At this time, the main power circuit forms a forward-operating flyback circuit, with battery 1 being discharged as a power source and battery 2 being charged as a load. When CTL is high, the main controller 1 controls the switch and rectifier 1 to operate in rectification mode; the control signal CTL is transmitted to the right side through the signal isolator, and the main controller 2 controls the switch and rectifier 2 to operate in switching mode. At this time, the main power circuit forms a reverse-operating flyback circuit, with battery 1 being charged as a load and battery 2 being discharged as a power source.

[0064] Furthermore, the first main controller 1 or the second main controller 2 includes a PWM controller and a synchronous rectifier controller connected in parallel, such as... Figure 4 As shown above, in switching mode, the PWM controller is active while the synchronous rectifier controller is inactive; in rectification mode, the PWM controller is inactive while the synchronous rectifier controller is active.

[0065] The PWM controller can employ any existing control method, such as... Figure 14 The voltage-type control method shown uses the PMW_EN signal to cut off or turn off the GT port of the PWM controller, thereby controlling whether the module operates. The synchronous rectifier controller can employ any existing control method, such as... Figure 7 Typical discontinuous mode synchronous rectification control uses the RS_EN signal to disconnect from the GT port, thereby controlling whether the module works.

[0066] Furthermore, the first switch and rectifier device 1 is a first MOSFET TR1, and the second switch and rectifier device 2 is a second MOSFET TR2. The source of the first MOSFET TR1 is connected to ground GND_P on one side of the first winding of the transformer, and the source of the second MOSFET TR2 is connected to ground GND_S on one side of the second winding of the transformer. The drain of the first MOSFET TR1 is connected to one end of the first winding, and the drain of the second MOSFET TR2 is connected to one end of the second winding. The gate of the first MOSFET TR1 is connected to the first master controller 1, and the gate of the second MOSFET TR2 is connected to the second master controller 2.

[0067] Furthermore, the first bidirectional switching circuit 1 or the second bidirectional switching circuit 2, as follows: Figure 5As shown, the circuit includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a first comparator COMP1, a second comparator COMP2, a third comparator COMP3, a first capacitor C1, a first RS flip-flop RS1, a first NOT gate NOT1, and a first AND gate AND1. The inverting input of the second comparator COMP2 serves as the input of either the first bidirectional switching circuit 1 or the second bidirectional switching circuit 2. One end of the first resistor R1 is connected to one end of either the first winding or the second winding. The other end of the first resistor R1 is connected to one end of the second resistor R2 and the inverting input of the third comparator COMP3. The reference voltage REF is input to the non-inverting inputs of the third comparator COMP3, the second comparator COMP2, and the first comparator COMP1. The output of the third comparator COMP3 is connected to one end of the third resistor R3, and the other end of the third resistor is connected to one end of the first capacitor C1, one end of the fourth resistor R4, and the inverting input of the first comparator COMP1. The other ends of the second resistor R2, the first capacitor C1, and the fourth resistor R4 are connected to ground GND_P on the first winding side or ground GND_S on the second winding side. The output of the first comparator COMP1 is connected to the S terminal of the first RS flip-flop RS1. The output of the second comparator COMP2 is connected to one input of the first AND gate AND1 and the input of the first NOT gate NOT1. The output of the first NOT gate NOT1 is connected to the R terminal of the first RS flip-flop RS1 and outputs the synchronous rectification control signal SR_EN to the synchronous rectification controller in the first or second master controller. The Q terminal of the first RS flip-flop RS1 is connected to the other input of the first AND gate AND1. The output of the first AND gate AND1 outputs the PWM control signal PWM_EN to the PWM controller in the first or second master controller.

[0068] The following is combined with Figures 4 to 6 Explanation of the working principle of this invention:

[0069] According to the background technology description, when the primary and secondary PWM controllers operate simultaneously, it leads to a reliability problem caused by the simultaneous conduction of the primary and secondary MOSFETs. In this invention, to solve the problem of simultaneous conduction of the primary and secondary MOSFETs, when the bidirectional switching circuit wants to control the local PWM controller, it needs to detect whether the opposite PWM controller has stopped operating. This is achieved in the following way: the bidirectional switching circuit couples the winding voltage of the transformer (which can be the main power winding or the auxiliary winding). When it detects that the transformer voltage is still in a high-low transition state, it indicates that the opposite MOSFET is still switching. It is necessary to wait for the transformer winding voltage to reach a stable value before controlling the local PWM controller. Because the primary and secondary circuits are completely symmetrical, in... Figure 6In the waveform diagram of the key nodes, the prefix P_ represents the device or signal on the primary side of the transformer, and the prefix S_ represents the device or signal on the secondary side of the transformer.

[0070] When the primary-side control signal P_CTL=0, it operates in the positive direction. In this case, the control signal will control the PWM control signal P_PWM_EN output by the primary-side bidirectional switching circuit to equalize 1, thus controlling the primary-side PWM controller to operate. Simultaneously, it will control the synchronous rectification control signal P_SR_EN output by the primary-side bidirectional switching circuit to equalize 0, thus disabling the primary-side synchronous rectification controller. At the same time, the signal isolation device outputs signal S_CTL=1. This S_CTL signal will then control the PWM signal S_PWM_EN output by the secondary-side bidirectional switching circuit to equalize 0, thus disabling the secondary-side PWM controller. Furthermore, it will control the synchronous rectification control signal S_SR_EN output by the secondary-side bidirectional switching circuit to equalize 1, thus operating the secondary-side synchronous rectification controller.

[0071] Combined with Figure 6 :

[0072] Before time t1, P_CTL=0, P_PWM_EN=1, the primary-side PWM controller is working, P_SR_EN=0, the primary-side synchronous rectifier controller is not working; S_CTL=1, P_PWM_EN=0, the primary-side PWM controller is not working, S_SR_EN=1, the secondary-side synchronous rectifier controller is working.

[0073] At time t1, P_CTL changes from 0 to 1. At this time, P_PWM_EN=0, the primary-side PWM controller is not working, and P_SR_EN=1, the primary-side synchronous rectifier controller is working. Due to the transmission delay of the signal isolation device, S_CTL remains at 1, and the secondary-side synchronous rectifier controller is working. As described in the background art, when the primary and secondary-side synchronous rectifier controllers are working simultaneously, there is a dead time, which does not cause reliability issues.

[0074] At time t2, S_CTL becomes 0. At this point, the voltage VDS of the transformer secondary winding remains high (i.e., the voltage across battery 2), indicating that the primary-side PWM controller is no longer operating. The comparator S_COMP3 outputs a low level, causing the voltage across capacitor S_C1 to drop. When the voltage of S_C1 falls below the reference voltage REF, the S-input of the S_RS1 flip-flop receives a rising edge signal. At this time, the Q-output of S_RS1 goes high, and the output of comparator S_COMP2 also goes high, ultimately causing the AND gate S_AND1 to output a high level, controlling the secondary-side PWM controller. During the switch from forward to reverse operation, the PWM controllers on both the primary and secondary sides will not operate simultaneously.

[0075] At time t3, P_CTL changes from 1 to 0, at which point P_SR_EN=1, the primary-side synchronous rectifier controller operates, and comparator P_COMP2 outputs a high level. However, due to the transmission delay of the signal isolation device, the secondary-side S_CTL signal has not yet changed to 1. Therefore, the secondary-side PWM controller is still operating, the voltage of P_VDS is a square wave signal, and the output of P_COMP3 is also a square wave signal, causing the average voltage of P_C1 to be higher than the reference voltage REF. The output of comparator P_COMP1 remains low, P_RS1 also outputs a low level, and the output signal P_PWM_EN of AND gate P_AND1 is also low. Therefore, the primary-side PWM controller does not operate, thus avoiding simultaneous operation of the primary and secondary-side PWM controllers.

[0076] At time t4, S_CTL becomes 1, the secondary-side PWM controller is off, and the secondary-side synchronous rectifier controller is on. At this time, both MOSFETs TR1 and TR2 on the primary and secondary sides are off, the P_VDS signal remains high, and comparator P_COMP3 outputs a low level. The voltage of capacitor C1 gradually decreases to the threshold REF, comparator P_COMP1 outputs a rising edge signal, and the Q terminal of P_RS1 outputs a high level. At time t3, comparator P_COMP2 has already output a high level, therefore, AND gate P_AND1 outputs a high level to control the primary-side PWM controller. That is, the primary-side PWM controller only operates when P_CTL=0 and P_VDS is high (the secondary-side PWM controller is off).

[0077] Example 2

[0078] Unlike Embodiment 1, which uses the average voltage of the transformer winding to determine whether the opposite MOSFET is in a switching state, Embodiment 2 uses the edge signal of the transformer winding to determine whether the opposite MOSFET is in a switching state. Therefore, the bidirectional switching circuit in Embodiment 2 differs from that in Embodiment 1.

[0079] like Figure 8As shown, the first or second bidirectional switching circuit of this embodiment includes a first resistor R1, a second resistor R2, a counter, a second comparator COMP2, a first RS flip-flop RS1, a first NOT gate NOT1, and a first AND gate AND1. The inverting input of the second comparator COMP2 serves as the input of either the first or second bidirectional switching circuit 1, and the non-inverting input of the second comparator COMP2 receives a reference voltage REF. One end of the first resistor R1 is connected to one end of either the first or second winding. The other end of the first resistor R1 is connected to one end of the second resistor R2 and the reset input port RS of the counter. The other end of the second resistor R2 is connected to ground GND_P on one side of the first winding or ground GND_S on the other side of the second winding. The clock input port CT of the counter receives a set number of square wave signals CLK. The output OUT of the counter is connected to the S terminal of the first RS flip-flop RS1, and the output of the second comparator COMP2 is connected to one input of the first AND gate AND1 and the input of the first NOT gate NOT1. The output of the first NOT gate (NOT1) is connected to the R terminal of the first RS flip-flop (RS1), and outputs the synchronous rectification control signal SR_EN. The Q terminal of the first RS flip-flop (RS1) is connected to the other input of the first AND gate (AND1). The output of the first AND gate (AND1) outputs the PWM control signal PWM_EN.

[0080] The working principle of the bidirectional switching circuit in this embodiment is as follows: When the control signal CTL=0, COMP2 outputs a high-level signal, and the synchronous rectification control signal SR_EN=0, controlling the synchronous rectification controller to not work. When the opposite MOSFET is still working, VDS outputs a square wave signal. The RS terminal of the counter is the reset input port. When a falling edge is received, it controls the counter to reset, so that the output port OUT remains low. When the opposite MOSFET is not working, VDS will maintain a high voltage. At this time, the RS port will not receive a reset signal. When the clock input port CT receives a set number of square wave signals, it will control the output port OUT to output a high level. At this time, the first flip-flop RS1 will output a high level, and the AND gate AND1 will output a high level, controlling the PWM control to work.

[0081] The circuit connections and working principles of this embodiment, except for the bidirectional switching circuit, as well as the battery bidirectional balancing control method, are the same as those in Embodiment 1, and will not be repeated here.

[0082] Example 3

[0083] In Embodiment 3, the synchronous rectifier controller from Embodiments 1 and 2 is removed. Diodes D1 and D2 are added between the drain and source of power transistors TR1 and TR2 as freewheeling diodes for reverse and forward operation, respectively. The bidirectional switching circuit can adopt the circuits from Embodiments 1 and 2.

[0084] like Figure 9 As shown, the first master controller 1 or the second master controller 2 includes a PWM controller. The first switching and rectifying device 1 includes a first MOSFET TR1 and a first diode D1. The second switching and rectifying device 2 includes a second MOSFET TR2 and a second diode D2. The anode of the first diode D1 is connected to the source of the first MOSFET TR1, and the cathode of the first diode D1 is connected to the drain of the first MOSFET TR1. The anode of the second diode D2 is connected to the source of the second MOSFET TR2, and the cathode of the second diode D2 is connected to the drain of the second MOSFET TR2.

[0085] Its working principle is as follows: In forward operation, MOSFET TR1 is turned on, diode D1 is not working, and MOSFET TR2 is not working. MOSFET TR1 acts as the main MOSFET, and diode D2 acts as the freewheeling diode, forming a flyback circuit with primary-side input and secondary-side output. In reverse operation, MOSFET TR2 is turned on, diode D2 is not working, and MOSFET TR1 is not working. MOSFET TR2 acts as the main MOSFET, and diode D1 acts as the freewheeling diode, forming a flyback circuit with secondary-side input and primary-side output.

[0086] This embodiment omits the synchronous rectifier controller. The only difference in the bidirectional switching circuit is the absence of the synchronous rectifier control signal SR_EN. The connections and operating principles of other components, as well as the connections of other circuit modules and the bidirectional battery balancing control method, are the same as in Embodiment 1 or Embodiment 2. These will not be elaborated upon here.

[0087] Example 4

[0088] Unlike embodiments one through three, in embodiment four, the bidirectional switching circuit ensures that the PWM controllers on the primary and secondary sides do not operate simultaneously by providing a delay to the PWM controllers. This is achieved instead of detecting the voltage of the transformer windings through the bidirectional switching circuit.

[0089] On one hand, a battery bidirectional equalization control method according to this embodiment includes the following steps:

[0090] S1. The first bidirectional switching circuit and signal isolation device receive external control signals;

[0091] S2. If the control signal is a positive working signal, after a certain delay, the first bidirectional switching circuit controls the first switch and rectifier to turn on through the first master controller; the signal isolation device flips the control signal and outputs it to the second bidirectional switching circuit, and then proceeds to S3.

[0092] If the control signal is a reverse working signal, the first bidirectional switching circuit controls the first switch and rectifier to turn off through the first master controller; the signal isolation device flips the control signal and outputs it to the second bidirectional switching circuit, and then switches to S4.

[0093] S3. The second bidirectional switching circuit controls the second switch and rectifier to turn off through the second master controller, and returns to S1.

[0094] S4. After a certain delay, the second bidirectional switching circuit controls the second switch and rectifier to turn on through the second main controller, and returns to S1.

[0095] The control signal CTL controls the battery bidirectional equalization control circuit to operate in either the forward or reverse direction. The control signal CTL can be high or low, indicating that the battery bidirectional equalization control circuit operates in the forward direction. For ease of description, this embodiment uses the case of CTL being low, indicating the battery bidirectional equalization control circuit is operating in the forward direction, but this does not imply that the scope of protection of this invention is limited to this.

[0096] Signal isolation devices, due to their inherent characteristics, typically experience a transmission delay. After receiving the control signal CTL, there is a delay before the output of the toggled control signal; this is determined by the device's inherent features. Of course, signal isolation devices without delay can also meet the requirements of this invention.

[0097] On the other hand, the battery bidirectional equalization control circuit of this embodiment does not require the detection of the voltage of the transformer winding, so the internal component connection relationship of the bidirectional switching circuit is different from that of Embodiments 1 to 3.

[0098] In this embodiment, when the main controller includes a PWM controller, the first bidirectional switching circuit 1 or the second bidirectional switching circuit 2 is as follows: Figure 11As shown, the circuit includes a fourth comparator COMP7, a fifth comparator COMP8, a fifth resistor R5, a first transistor Q1, and a second capacitor C2. The inverting input of the fourth comparator COMP7 serves as the input of either the first bidirectional switching circuit 1 or the second bidirectional switching circuit 2. The non-inverting input of the fourth comparator COMP7 and the inverting input of the fifth comparator COMP8 are connected to a reference voltage REF. The output of the fourth comparator COMP7 is connected to one end of the fifth resistor R5 and the base of the first transistor Q1. The other end of the fifth resistor R5 is connected to the emitter of the first transistor Q1, one end of the second capacitor C2, and the non-inverting input of the fifth comparator COMP8. The collector of the first transistor Q1 and the other end of the second capacitor C2 are connected to ground GND_P on the first winding side or ground GND_S on the second winding side. The output of the fifth comparator COMP8 outputs a PWM control signal PWM_EN to the PWM controller.

[0099] When the main controller includes a PWM controller and a synchronous rectifier controller, the first bidirectional switching circuit 1 or the second bidirectional switching circuit 2 is as follows: Figure 12 As shown, the circuit includes a fourth comparator COMP7, a fifth comparator COMP8, a fifth resistor R5, a first transistor Q1, a second capacitor C2, and a second NOT gate NOT2. The inverting input of the fourth comparator COMP7 serves as the input of either the first bidirectional switching circuit 1 or the second bidirectional switching circuit 2. The non-inverting input of the fourth comparator COMP7 and the inverting input of the fifth comparator COMP8 are connected to the reference voltage REF. The output of the fourth comparator COMP7 is connected to one end of the fifth resistor R5, the base of the first transistor Q1, and the input of the second NOT gate NOT2. The output of the second NOT gate NOT2 outputs the synchronous rectification control signal SR_EN to the synchronous rectification controller. The collector of the first transistor Q1 and the other end of the second capacitor C2 are connected to ground GND_P on the first winding side or ground GND_S on the second winding side. The output of the fifth comparator COMP8 outputs the PWM control signal PWM_EN to the PWM controller.

[0100] Combination Figure 13 This embodiment explains its operating principle when a synchronous rectifier controller is included:

[0101] Before time t1, P_CTL=0, P_PWM_EN=1, the primary-side PWM controller is working, P_SR_EN=0, the primary-side synchronous rectifier controller is not working; S_CTL=1, P_PWM_EN=0, the secondary-side PWM controller is not working, S_SR_EN=1, the secondary-side synchronous rectifier controller is working.

[0102] At time t1, P_CTL changes from 0 to 1, comparator P_COM7 outputs a low level. Due to the presence of NPN transistor P_Q1, the voltage of capacitor P_C2 is quickly pulled to 0V. At this time, P_PWM_EN=0, the primary-side PWM controller does not work, and simultaneously, the synchronous rectifier controller P_SR_EN=1 works. Due to the transmission delay of the signal isolation device, S_CTL remains at 1, and the secondary-side synchronous rectifier controller works. As described in the background art, when the primary and secondary-side synchronous rectifier controllers work simultaneously, it does not cause reliability issues.

[0103] At time t2, S_CTL becomes 0, S_COMP7 outputs a high level, and due to the presence of resistor S_R3, the voltage of S_C2 rises slowly, reaching the reference voltage REF after a delay. S_COMP8 then outputs a high level, and S_PWM_EN=1 controls the operation of the secondary PWM controller. The delay function of the bidirectional switching circuit in this embodiment is generated by the charging of capacitor C2. The time it takes for the voltage of capacitor C2 to rise from 0 to the reference voltage REF is the delay of the bidirectional switching circuit. Therefore, adjusting the value of capacitor C2 can control the delay.

[0104] At time t3, P_CTL changes from 1 to 0. At this time, P_COMP7 outputs a high level. Due to the presence of resistor P_R3, the voltage across capacitor P_C2 rises slowly but has not yet reached the threshold REF. Therefore, the output of P_COMP8 remains low, and the primary-side PWM controller is not operating. Simultaneously, NOT2 outputs a low level, P_SR_EN = 0, and the synchronous rectification on the primary side is not working. Due to the transmission delay, the S_CTL signal remains 0, and S_PWM_EN = 1, so the secondary-side PWM controller is still operating. Due to the delay effect of capacitor P_C2, the primary and secondary-side PWM controllers will not operate simultaneously. The delay of C2 must be greater than the delay of the signal isolation device.

[0105] At time t4, S_CTL becomes 1, and similarly, the capacitor voltage of S_C2 is quickly pulled to 0. The secondary PWM controller does not work, while SR_EN=1 and the secondary synchronous rectification works.

[0106] At time t5, the voltage across capacitor P_C2 reaches the threshold REF, and comparator P_COMP8 outputs a high level to control the primary-side PWM controller. In practical engineering applications, setting a sufficiently large delay can prevent the primary and secondary-side PWM controllers from operating simultaneously.

[0107] The above description is merely illustrative of the embodiments of the present invention and is not intended to limit the present invention. For those skilled in the art, any modifications, equivalent substitutions, improvements, etc., made without creative effort within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A bidirectional equalization control method for a battery, characterized by, The battery bidirectional equalization control circuit comprises a transformer and a signal isolation device, further comprises a first switch and a rectifier device, a first main controller and a first bidirectional switching circuit which are sequentially connected between a first winding of the transformer and one end of the signal isolation device, and a second switch and a rectifier device, a second main controller and a second bidirectional switching circuit which are sequentially connected between a second winding of the transformer and the other end of the signal isolation device; the battery bidirectional equalization control method comprises the following steps: S1, the first bidirectional switching circuit and the signal isolation device receive an external control signal; S2, if the control signal is a forward working signal, the first bidirectional switching circuit detects the average working voltage of the first winding of the transformer, when the working voltage of the first winding does not exist high-low jump, is a stable high level voltage, the first bidirectional switching circuit controls the first switch and the rectifier device to be turned on through the first main controller; or, the first bidirectional switching circuit detects the edge signal of the first winding of the transformer, when the falling edge is received, the output port is maintained at low level, the first switch and the rectifier device are controlled to be not turned on, when the received voltage signal is maintained at high voltage, the output port outputs high level, the first switch and the rectifier device are controlled to be turned on; the signal isolation device flips the control signal and outputs it to the second bidirectional switching circuit, and turns to S3; If the control signal is a reverse working signal, the first bidirectional switching circuit controls the first switch and the rectifier device to be turned off through the first main controller; the signal isolation device flips the control signal and outputs it to the second bidirectional switching circuit, and turns to S4; S3, the second bidirectional switching circuit controls the second switch and the rectifier device to be turned off through the second main controller, and returns to S1; S4, the second bidirectional switching circuit detects the average working voltage of the second winding of the transformer, when the working voltage of the second winding does not exist high-low jump, is a stable high level voltage, the second bidirectional switching circuit controls the second switch and the rectifier device to be turned on through the second main controller, or, the second bidirectional switching circuit detects the edge signal of the second winding of the transformer, when the falling edge is received, the output port is maintained at low level, the second switch and the rectifier device are controlled to be not turned on, when the received voltage signal is maintained at high voltage, the output port outputs high level, the second switch and the rectifier device are controlled to be turned on; returns to S1.

2. A bidirectional equalization control circuit for a battery comprising a transformer and a signal isolation device, characterized in that, Further comprises a first switch and a rectifier device, a first main controller and a first bidirectional switching circuit which are sequentially connected between a first winding of the transformer and one end of the signal isolation device, and a second switch and a rectifier device, a second main controller and a second bidirectional switching circuit which are sequentially connected between a second winding of the transformer and the other end of the signal isolation device; The input end of the first bidirectional switching circuit inputs a control signal, controls the first switch and the rectifier device to be turned off according to the control signal; detects the average voltage signal of the first winding of the transformer, and controls the first switch and the rectifier device to be turned on according to whether the control signal and the average voltage signal of the first winding exist high-low jump; or The first bidirectional switching circuit detects the edge signal of the first winding of the transformer, and controls the first switch and the rectifier device to be turned on according to whether the edge signal of the first winding exists falling edge; One end of the signal isolation device receives a control signal and outputs the control signal from the other end of the signal isolation device to the second bidirectional switch circuit after transmission; The input end of the second bidirectional switch circuit inputs the control signal transmitted by the signal isolation device, and controls the second switch and the rectifier device to be turned off according to the control signal transmitted by the signal isolation device; The average voltage signal of the second winding of the transformer is detected, and the second switch and the rectifier device are controlled to be turned on according to whether the control signal transmitted by the signal isolation device and the average voltage signal of the second winding exist high-low jump; or the second bidirectional switch circuit detects the edge signal of the second winding of the transformer, and controls the second switch and the rectifier device to be turned on according to whether the edge signal of the second winding exists falling edge.

3. The bidirectional equalization control circuit for batteries according to claim 2, characterized in that, The first master controller or the second master controller comprises a PWM controller.

4. The bidirectional equalization control circuit for batteries according to claim 3, characterized in that, The first switch and the rectifier device comprise a first MOS tube (TR1) and a first diode (D1), and the second switch and the rectifier device comprise a second MOS tube (TR2) and a second diode (D2); the anode of the first diode (D1) is connected to the source of the first MOS tube (TR1), the anode of the second diode (D2) and the source of the second MOS tube (TR2) respectively; the cathode of the first diode (D1) is connected to the drain of the first MOS tube (TR1) and one end of the first winding respectively; the cathode of the second diode (D2) is connected to the drain of the second MOS tube (TR2) and one end of the second winding respectively; the gate of the first MOS tube (TR1) is connected to the PWM controller in the first master controller, and the gate of the second MOS tube (TR2) is connected to the PWM controller in the second master controller.

5. The bidirectional equalization control circuit for batteries of claim 2, wherein, The first master controller or the second master controller comprises a PWM controller and a synchronous rectification controller in parallel.

6. The bidirectional equalization control circuit for batteries according to claim 5, characterized in that, The first switch and the rectifier device are a first MOS tube (TR1), and the second switch and the rectifier device are a second MOS tube (TR2); the source of the first MOS tube (TR1) is connected to the ground (GND_P) on one side of the first winding, and the source of the second MOS tube (TR2) is connected to the ground (GND_S) on one side of the second winding; the drain of the first MOS tube (TR1) is connected to one end of the first winding; the drain of the second MOS tube (TR2) is connected to one end of the second winding; the gate of the first MOS tube (TR1) is connected to the first master controller, and the gate of the second MOS tube (TR2) is connected to the second master controller.

7. The bidirectional equalization control circuit of the battery according to claim 3 or 4, characterized in that, The first bidirectional switching circuit or the second bidirectional switching circuit comprises a first resistor (R1), a second resistor (R2), a third resistor (R3), a fourth resistor (R4), a first comparator (COMP1), a second comparator (COMP2), a third comparator (COMP3), a first capacitor (C1), a first RS flip-flop (RS1), a first NOT gate (NOT1) and a first AND gate (AND1); a reverse input end of the second comparator (COMP2) is an input end of the first bidirectional switching circuit or an input end of the second bidirectional switching circuit; one end of the first resistor (R1) is connected to one end of the first winding or one end of the second winding; the other end of the first resistor (R1) is connected to one end of the second resistor (R2) and a reverse input end of the third comparator (COMP3) respectively; a forward input end of the third comparator (COMP3), a forward input end of the second comparator (COMP2) and a forward input end of the first comparator (COMP1) input a reference voltage (REF) respectively; one end of the third resistor (R3) connected to an output end of the third comparator (COMP3), the other end of the third resistor is connected to one end of the first capacitor (C1), one end of the fourth resistor (R4) and a reverse input end of the first comparator (COMP1) respectively; the other end of the second resistor (R2), the other end of the first capacitor (C1) and the other end of the fourth resistor (R4) are connected to ground (GND_P) on one side of the first winding or ground (GND_S) on one side of the second winding; an output end of the first comparator (COMP1) is connected to an S end of the first RS flip-flop (RS1), an output end of the second comparator (COMP2) is connected to one input end of the first AND gate (AND1) and an input end of the first NOT gate (NOT1) respectively; an output end of the first NOT gate (NOT1) is connected to an R end of the first RS flip-flop (RS1); a Q end of the first RS flip-flop (RS1) is connected to the other input end of the first AND gate (AND1); an output end of the first AND gate (AND1) outputs a PWM control signal (PWM_EN) to a PWM controller of the first master controller or a PWM controller of the second master controller.

8. The bidirectional equalization control circuit of the battery according to claim 5 or 6, characterized in that, The first bidirectional switching circuit or the second bidirectional switching circuit comprises a first resistor (R1), a second resistor (R2), a third resistor (R3), a fourth resistor (R4), a first comparator (COMP1), a second comparator (COMP2), a third comparator (COMP3), a first capacitor (C1), a first RS flip-flop (RS1), a first NOT gate (NOT1) and a first AND gate (AND1); a reverse input end of the second comparator (COMP2) is an input end of the first bidirectional switching circuit or an input end of the second bidirectional switching circuit; one end of the first resistor (R1) is connected to one end of the first winding or one end of the second winding; the other end of the first resistor (R1) is connected to one end of the second resistor (R2) and a reverse input end of the third comparator (COMP3) respectively; a forward input end of the third comparator (COMP3), a forward input end of the second comparator (COMP2) and a forward input end of the first comparator (COMP1) input a reference voltage (REF) respectively; one end of the third resistor (R3) connected to an output end of the third comparator (COMP3), the other end of the third resistor is connected to one end of the first capacitor (C1), one end of the fourth resistor (R4) and a reverse input end of the first comparator (COMP1) respectively; the other end of the second resistor (R2), the other end of the first capacitor (C1) and the other end of the fourth resistor (R4) are connected to ground (GND_P) on one side of the first winding or ground (GND_S) on one side of the second winding; an output end of the first comparator (COMP1) is connected to an S end of the first RS flip-flop (RS1), an output end of the second comparator (COMP2) is connected to one input end of the first AND gate (AND1) and an input end of the first NOT gate (NOT1) respectively; an output end of the first NOT gate (NOT1) is connected to an R end of the first RS flip-flop (RS1) and outputs a synchronous rectification control signal (SR_EN) to a synchronous rectification controller of the first master controller or a synchronous rectification controller of the second master controller; a Q end of the first RS flip-flop (RS1) is connected to the other input end of the first AND gate (AND1); an output end of the first AND gate (AND1) outputs a PWM control signal (PWM_EN) to a PWM controller of the first master controller or a PWM controller of the second master controller.

9. The bidirectional equalization control circuit of the battery according to claim 3 or 4, characterized in that, The first bidirectional switching circuit or the second bidirectional switching circuit comprises a first resistor (R1), a second resistor (R2), a counter, a second comparator (COMP2), a first RS flip-flop (RS1) and a first AND gate (AND1); a reverse input end of the second comparator (COMP2) is an input end of the first bidirectional switching circuit or an input end of the second bidirectional switching circuit, and a forward input end of the second comparator (COMP2) inputs a reference voltage (REF); one end of the first resistor (R1) is connected to one end of the first winding or one end of the second winding; the other end of the first resistor (R1) is respectively connected to one end of the second resistor (R2) and a reset input port RS of the counter; the other end of the second resistor (R2) is connected to ground (GND_P) on one side of the first winding or ground (GND_S) on one side of the second winding; a clock input port CT of the counter inputs a square wave signal (CLK) of a set number; an output end OUT of the counter is connected to an S end of the first RS flip-flop (RS1); an output end of the second comparator (COMP2) is respectively connected to one input end of the first AND gate (AND1) and an input end of a first NOT gate (NOT1); an output end of the first NOT gate (NOT1) is connected to an R end of the first RS flip-flop (RS1); a Q end of the first RS flip-flop (RS1) is connected to the other input end of the first AND gate (AND1); and an output end of the first AND gate (AND1) outputs a PWM control signal (PWM_EN) to a PWM controller of the first master controller or a PWM controller of the second master controller.

10. The bidirectional equalization control circuit of the battery according to claim 5 or 6, characterized in that, The first bidirectional switching circuit or the second bidirectional switching circuit comprises a first resistor (R1), a second resistor (R2), a counter, a second comparator (COMP2), a first RS flip-flop (RS1), a first NOT gate (NOT1) and a first AND gate (AND1); a reverse input end of the second comparator (COMP2) is an input end of the first bidirectional switching circuit or an input end of the second bidirectional switching circuit, and a forward input end of the second comparator (COMP2) inputs a reference voltage (REF); one end of the first resistor (R1) is connected to one end of the first winding or one end of the second winding; the other end of the first resistor (R1) is connected to one end of the second resistor (R2) and a reset input port RS of the counter respectively; the other end of the second resistor (R2) is connected to ground (GND_P) on one side of the first winding or ground (GND_S) on one side of the second winding; a clock input port CT of the counter inputs a square wave signal (CLK) of a set number; an output end OUT of the counter is connected to an S end of the first RS flip-flop (RS1); an output end of the second comparator (COMP2) is connected to one input end of the first AND gate (AND1) and an input end of the first NOT gate (NOT1) respectively; an output end of the first NOT gate (NOT1) is connected to an R end of the first RS flip-flop (RS1), and outputs a synchronous rectification control signal (SR_EN) to a synchronous rectification controller of the first master controller or a synchronous rectification controller of the second master controller; a Q end of the first RS flip-flop (RS1) is connected to the other input end of the first AND gate (AND1); and an output end of the first AND gate (AND1) outputs a PWM control signal (PWM_EN) to a PWM controller of the first master controller or a PWM controller of the second master controller.

11. The bidirectional equalization control circuit of the battery according to claim 3 or 4, characterized in that, When the control signal is a forward working signal, the first bidirectional switching circuit delays for a period of time, and then controls the first switch and the rectifier to be turned on through the first main controller; when the control signal is a reverse working signal, the second bidirectional switching circuit delays for a period of time, and then controls the second switch and the rectifier to be turned on through the second main controller; the first bidirectional switching circuit or the second bidirectional switching circuit comprises a fourth comparator (COMP7), a fifth comparator (COMP8), a fifth resistor (R5), a first triode (Q1) and a second capacitor (C2); the reverse input end of the fourth comparator (COMP7) is used as the input end of the first bidirectional switching circuit or the input end of the second bidirectional switching circuit, the forward input end of the fourth comparator (COMP7) and the reverse input end of the fifth comparator (COMP8) input a reference voltage (REF); the output end of the fourth comparator (COMP7) is connected with one end of the fifth resistor (R5) and the base of the first triode (Q1) respectively; the other end of the fifth resistor (R5) is connected with the emitter of the first triode (Q1), one end of the second capacitor (C2) and the forward input end of the fifth comparator (COMP8) respectively; the collector of the first triode (Q1) and the other end of the second capacitor (C2) are connected with the ground (GND_P) on one side of the first winding or the ground (GND_S) on one side of the second winding; the output end of the fifth comparator (COMP8) outputs a PWM control signal (PWM_EN) to the PWM controller of the first main controller or the PWM controller of the second main controller.

12. The bidirectional equalization control circuit of the battery according to claim 5 or 6, characterized by, When the control signal is a forward working signal, the first bidirectional switching circuit delays for a period of time, and then controls the first switch and the rectifier to be turned on through the first main controller; when the control signal is a reverse working signal, the second bidirectional switching circuit delays for a period of time, and then controls the second switch and the rectifier to be turned on through the second main controller; the first bidirectional switching circuit or the second bidirectional switching circuit comprises a fourth comparator (COMP7), a fifth comparator (COMP8), a fifth resistor (R5), a first triode (Q1), a second capacitor (C2) and a second NOT gate (NOT2); the reverse input end of the fourth comparator (COMP7) is used as the input end of the first bidirectional switching circuit or the input end of the second bidirectional switching circuit, the forward input end of the fourth comparator (COMP7) and the reverse input end of the fifth comparator (COMP8) input a reference voltage (REF); the output end of the fourth comparator (COMP7) is connected with one end of the fifth resistor (R5), the base of the first triode (Q1) and the input end of the second NOT gate (NOT2) respectively; the output end of the second NOT gate (NOT2) outputs a synchronous rectification control signal (SR_EN) to the synchronous rectification controller of the first main controller or the synchronous rectification controller of the second main controller; the collector of the first triode (Q1) and the other end of the second capacitor (C2) are connected with the ground (GND_P) on one side of the first winding or the ground (GND_S) on one side of the second winding; the output end of the fifth comparator (COMP8) outputs a PWM control signal (PWM_EN) to the PWM controller of the first main controller or the PWM controller of the second main controller.

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