Low-cost BMS isolation drive circuit scheme and implementation method

Abstract

The invention discloses a low-cost BMS isolation driving circuit scheme and an implementation method, and relates to the technical field of isolation driving, the low-cost BMS isolation driving circuit scheme comprises a driving module and a conversion module, the driving module and the conversion module are connected in parallel, and the driving module is used for being connected with external equipment and the conversion module and sending an isolation driving signal. The conversion module is used for outputting a 12V isolated voltage-stabilized power supply; the driving module comprises a signal processing unit and an output control unit, the conversion module comprises a voltage processing unit and a voltage output unit, the signal processing unit is electrically connected with the output control unit and the voltage processing unit, and the voltage processing unit is electrically connected with the voltage output unit. Through cooperative operation of the triode Q26, the photoelectric coupler U2, the MOS tube Q25 and the common-mode inductor T1, cost effectiveness and simplified design are achieved, and meanwhile good electrical isolation performance and voltage output stability are kept.

Description

Technical Field

[0001] The present invention relates to the field of isolation drive technology, and in particular to a low-cost BMS isolation drive circuit solution and an implementation method. Background Art

[0002] The Battery Management System (BMS) is one of the core components of electric vehicles and energy storage systems. It is mainly responsible for the charge and discharge control, status monitoring, temperature management and other functions of the battery pack. It ensures the safe operation and efficient use of the entire battery pack by monitoring the voltage, current and temperature of each battery cell in real time. In addition, the BMS can also predict the remaining life of the battery, help users arrange charging plans reasonably, and extend the service life of the battery.

[0003] In BMS, the isolation drive circuit is mainly used to protect the main control circuit from the influence of the external high-voltage battery pack, while ensuring the reliable drive of power switching devices such as MOSFET. Traditional isolation drive solutions usually use transformers or optocouplers to achieve electrical isolation, but these solutions have problems such as high cost, large size, and low efficiency, which limits their widespread application in cost-sensitive applications.

[0004] The Chinese invention patent with publication number CN111865106A provides a motor controller based on discrete silicon carbide power devices, including a power circuit, a digital control circuit and a SiC drive circuit; the power circuit includes a connected DC bus capacitor, a three-phase full-bridge inverter module and a heat sink; the three-phase full-bridge inverter module is composed of three groups of half-bridge topology structures; the two bridge arms of each group of half-bridge topology structures respectively include at least two SiC MOSFET tubes connected in parallel; the heat sink is arranged on the power board; each SiC MOSFET tube is respectively arranged on the heat sink; the DC bus capacitor includes a plurality of film capacitors connected in parallel; all film capacitors are evenly arranged on the side of the power board away from the heat sink; each SiCMOSFET tube is respectively connected to the film capacitor closest to it. The motor controller has the characteristics of low conduction loss and low switching loss, thereby improving efficiency; it can reduce stray inductance and has good stability and reliability.

[0005] In the actual operation of the above and similar motor controllers, relatively complex and cumbersome components are used to improve the electrical isolation performance of the circuit and the stability of the voltage output, which not only increases the difficulty of the circuit, but also increases the cost. On the other hand, there are also ways to reduce the manufacturing cost by reducing the components, but in that case, the electrical isolation performance of the circuit and the stability of the voltage output cannot be guaranteed. Summary of the invention

[0006] The object of the present invention is to provide a low-cost BMS isolation drive circuit solution and implementation method to solve the problems raised in the above background technology.

[0007] To achieve the above object, the present invention provides the following technical solutions: a low-cost BMS isolation drive circuit solution, including a drive module and a conversion module, the drive module and the conversion module are connected in parallel with each other, and the drive module is used to connect with an external device and the conversion module to send an isolated drive signal, and the conversion module is used to output a 12V isolated regulated power supply;

[0008] The driving module includes a signal processing unit and an output control unit, the conversion module includes a voltage processing unit and a voltage output unit, the signal processing unit is electrically connected to the output control unit and the voltage processing unit, and the voltage processing unit is electrically connected to the voltage output unit.

[0009] Furthermore, the signal processing unit includes an input circuit and a processing circuit, the input circuit is electrically connected to the processing circuit, and the processing circuit is electrically connected to the output control unit and the voltage processing unit;

[0010] The input circuit includes a transistor Q26, the base of the transistor Q26 is electrically connected to resistors R85 and R90, the emitter of the transistor Q26 is electrically connected to resistor R90, the collector of the transistor Q26 is electrically connected to the processing circuit, and the emitter of the transistor Q26 and the resistor R90 are both grounded, and the resistor R85 is electrically connected to the Para-DRV-MCU port.

[0011] Furthermore, the processing circuit includes a photocoupler U2, port 1 of the photocoupler U2 is electrically connected to a 3.3V port through a resistor R81, port 2 of the photocoupler U2 is electrically connected to the collector of a transistor Q26, port 3 of the photocoupler U2 is electrically connected to a resistor R84, the resistor R84 is electrically connected to a capacitor C36 and a voltage processing unit, port 2 of the photocoupler U2 is electrically connected to a resistor R80 and a resistor R83, and both the resistor R80 and the resistor R83 are electrically connected to an output control unit, and the resistor R80 is electrically connected to a voltage processing unit, and the resistor R83 is electrically connected to the resistor R84 and the voltage processing unit through the capacitor C36.

[0012] Furthermore, the output control unit includes a MOS tube Q25, a G port of the MOS tube Q25 is electrically connected to a resistor R83 and a capacitor C36, an S port of the MOS tube Q25 is electrically connected to a voltage processing unit and a resistor R80, and a D port of the MOS tube Q25 is electrically connected to an AUXG port.

[0013] Furthermore, the voltage processing unit includes a conversion circuit, a control circuit and a selection circuit, the conversion circuit is electrically connected to the capacitor C36, the resistor R80, the resistor R84, the S port of the MOS tube Q25, the control circuit and the voltage output unit, and the control circuit is electrically connected to the selection circuit, and the selection circuit is electrically connected to the voltage output unit;

[0014] The conversion circuit includes a common-mode inductor T1, a port 1 of the common-mode inductor T1 is electrically connected to the cathode of the diode D17 and the control circuit, and the anode of the diode D17 is also electrically connected to the control circuit, and a port 2 of the common-mode inductor T1 is electrically connected to a capacitor C34, a capacitor C36 and a resistor R84, and the capacitor C34 is grounded, a port 3 of the common-mode inductor T1 is electrically connected to a capacitor EC2, a capacitor C38 and a voltage output unit, and the capacitor EC2 and the capacitor C38 are connected in parallel to each other, and a port 4 of the common-mode inductor T1 is electrically connected to the first parallel loop, the resistor R80 and the S port of the MOS tube Q25 through a diode;

[0015] The first parallel circuit includes a capacitor EC1, a capacitor C35 and a diode. The capacitor EC1, the capacitor C35 and the diode are connected in parallel with each other. Meanwhile, the capacitor EC1, the capacitor C35 and the diode are electrically connected to the capacitor C36 and the resistor R84.

[0016] Furthermore, the control circuit includes a buck IC chip U3 and a connector CN, the 1st port and the 6th port of the buck IC chip U3 are both grounded, the 3rd port and the 4th port of the buck IC chip U3 are both electrically connected to the selection circuit through a resistor, and the 2nd port of the buck IC chip U3 is also electrically connected to the selection circuit, the 5th port of the buck IC chip U3 is electrically connected to the FB port, the 7th port of the buck IC chip U3 is electrically connected to the capacitor C37, the capacitor C37 is electrically connected to the 8th port of the buck IC chip U3, the resistor R91 and the 1st port of the common mode inductor T1 and the cathode of the diode D17, the resistor R91 is electrically connected to the capacitor C42, the capacitor C42 is electrically connected to the anode of the diode D17, and the capacitor C42 is grounded;

[0017] Port 1 of the connector CN is electrically connected to resistor R77 and resistor R79, port 2 of the connector CN is electrically connected to resistor R78 and resistor R82, ports 3 and 4 of the connector CN are both grounded, and resistor R77 and resistor R78 are both electrically connected to the 3.3V-MCU port, resistor R79 is electrically connected to the Addr0 port, and resistor R82 is electrically connected to the Addr1 port.

[0018] Furthermore, the selection circuit includes a second parallel circuit and a resistor R92, the second parallel circuit is electrically connected to a resistor R86, the resistor R86 is electrically connected to a capacitor C40 and a port 2 of a buck IC chip U3, the resistor R92 is electrically connected to an AUX-EN port, a capacitor C41 and a port 3 of a buck IC chip U3, and the capacitor C40 and the capacitor C41 are both grounded.

[0019] Furthermore, the second parallel circuit includes two diodes connected in parallel, the anode of one diode is electrically connected to the B+ port, the other diode is electrically connected to the P+ port, and the cathodes of the two diodes connected in parallel are electrically connected to the resistor R86.

[0020] Furthermore, the voltage output unit includes a 12VB port and a TP41 port, the 12VB port is electrically connected to the cathode of the diode D15, the anode of the diode D15 is electrically connected to the 12V+ port, the resistor R81, the resistor R87, the resistor R88, the capacitor C39 and the capacitor C38, and the resistor R87 and the capacitor C39 are connected in parallel to each other and are electrically connected to the 5-port of the step-down IC chip U3, and the resistor R87 is electrically connected to the resistor R95, the resistor R81, the resistor R88 and the resistor R95 are electrically connected to the TP41 port and the capacitor C38, and the resistor R81 and the resistor R88 are connected in parallel to each other.

[0021] A low-cost BMS isolation drive circuit implementation method is provided, wherein the implementation method uses the low-cost BMS isolation drive circuit solution described above.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] Firstly, the present invention forms an isolation driving circuit through a driving module and a conversion module, and divides the driving module into a signal processing unit and an output control unit, and divides the conversion module into a voltage processing unit and a voltage output unit, thereby facilitating maintenance and upgrading, and improving the flexibility and adaptability of the overall circuit solution;

[0024] Second: The present invention achieves cost-effectiveness and simplified design while maintaining good electrical isolation performance and voltage output stability through the coordinated operation of the triode Q26, the photocoupler U2, the MOS tube Q25 and the common mode inductor T1;

[0025] Thirdly, the present invention adopts the design of the step-down IC chip U3 and its voltage divider network so that the output voltage can be adjusted according to actual needs. Meanwhile, the setting of filtering elements such as capacitors further ensures the stability and reliability of the output voltage. Thus, the overall circuit solution reduces space occupation while ensuring the reliability and safety of long-term operation through existing prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A system block diagram of a low-cost BMS isolation drive circuit solution of the present invention;

[0027] Figure 2 is a circuit diagram of a driving module of the present invention;

[0028] Figure 3 FIG. 4 is a circuit diagram of the conversion module of the present invention. DETAILED DESCRIPTION

[0029] 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.

[0030] In the actual operation process of the motor controller, the electrical isolation performance of the circuit and the stability of the voltage output are improved through relatively complex and cumbersome components. The result of such implementation not only increases the difficulty of the circuit, but also increases the cost, which is not conducive to long-term use and maintenance. Similarly, there are also ways to reduce the manufacturing cost by reducing components, but the result of such implementation makes it impossible to guarantee the electrical isolation performance of the circuit and the stability of the voltage output. The technical solution of the present application divides the drive module into two parts, a signal processing unit and an output control unit, and divides the conversion module into a voltage processing unit and a voltage output unit, so as to facilitate maintenance and upgrading while improving the flexibility and adaptability of the overall circuit solution. At the same time, the technical solution achieves cost-effectiveness and simplified design through the coordinated operation of the triode Q26, the photocoupler U2, the MOS tube Q25 and the common mode inductor T1, while also maintaining good electrical isolation performance and voltage output stability.

[0031] refer to Figure 1-Figure 3This embodiment provides a low-cost BMS isolation drive circuit solution, which includes a drive module and a conversion module, wherein the drive module and the conversion module are connected in parallel. Specifically, the drive module is used to receive a 12V isolated regulated power supply sent by the conversion module, and output an isolated drive signal to the outside to control an external device. The conversion module is used to convert an external voltage into a 12V isolated regulated power supply, and output a 12V isolated regulated power supply to the drive module.

[0032] In this embodiment, the driving module includes a signal processing unit and an output control unit, and the conversion module includes a voltage processing unit and a voltage output unit. The signal processing unit is electrically connected to the output control unit and the voltage processing unit, and the voltage processing unit is electrically connected to the voltage output unit. Specifically, the signal processing unit includes an input circuit and a processing circuit, and the voltage processing unit includes a conversion circuit, a control circuit, and a selection circuit. The input circuit is electrically connected to the processing circuit, the processing circuit is electrically connected to the output control unit and the conversion circuit, the conversion circuit is electrically connected to the control circuit and the voltage output unit, the control circuit is electrically connected to the selection circuit, and the selection circuit is electrically connected to the voltage output unit.

[0033] In this embodiment, the input circuit includes a transistor Q26, the base of the transistor Q26 is electrically connected to resistors R85 and R90, the emitter of the transistor Q26 is electrically connected to resistor R90, the collector of the transistor Q26 is electrically connected to the processing circuit, and the emitter of the transistor Q26 and the resistor R90 are both grounded, and the resistor R85 is electrically connected to the Para-DRV-MCU port.

[0034] During the specific implementation process, the Para-DRV-MCU port is electrically connected to the microcontroller MCU, that is, information is exchanged with the microcontroller MCU. In other words, the input circuit receives the input signal transmitted from the microcontroller MCU, and divides and adjusts the voltage through resistors R85 and R90. At the same time, the transistor Q26 can amplify the received input signal.

[0035] Further, the processing circuit includes a photocoupler U2, port 1 of the photocoupler U2 is electrically connected to the 3.3V port through a resistor R81, port 2 of the photocoupler U2 is electrically connected to the collector of the transistor Q26, port 3 of the photocoupler U2 is electrically connected to a resistor R84, resistor R84 is electrically connected to a capacitor C36 and a voltage processing unit, port 2 of the photocoupler U2 is electrically connected to a resistor R80 and a resistor R83, and resistor R80 and resistor R83 are both electrically connected to the output control unit, and resistor R80 is electrically connected to the voltage processing unit, and resistor R83 is electrically connected to resistor R84 and the voltage processing unit through capacitor C36.

[0036] During the specific implementation process, the in-phase input terminal (port 2) of the photocoupler U2 is electrically connected to the collector of the transistor Q26, the inverting input terminal (port 3) of the photocoupler U2 is electrically connected to the resistor R84, the output terminal (port 4) of the photocoupler U2 is electrically connected to the resistor R80 and the resistor R83, and the Dr12V port (voltage processing unit) is voltage clamped for protection.

[0037] Furthermore, the output control unit includes a MOS tube Q25, a G port of the MOS tube Q25 is electrically connected to a resistor R83 and a capacitor C36, an S port of the MOS tube Q25 is electrically connected to a voltage processing unit and a resistor R80, and a D port of the MOS tube Q25 is electrically connected to an AUXG port.

[0038] In the process of specific implementation, resistor R80, resistor R83 and resistor R84 form a negative feedback network together and are used to stabilize the output voltage. At the same time, MOS tube Q25 acts as a switching device, and its gate (G port) is connected to the output end (4 port) of the photoelectric coupler U2, that is, it is controlled by the output of the photoelectric coupler U2. In other words, when the output of the photoelectric coupler U2 is a high level, the MOS tube Q25 is turned on and the external device is connected to the ground. When the output of the photoelectric coupler U2 is a low level, the MOS tube Q25 is turned off and the external device is disconnected from the ground.

[0039] That is to say, in the driving module, the AUXG port is the driving end of the MOS tube Q25 (parallel output). In the specific operation process, when the output signal of the Para-DRV-MCU port is high level, the conduction of the photoelectric coupler U2 is realized through the conduction of the transistor Q26, so that the MOS tube Q25 is turned on, and the isolated power supply Dr12V (the power supply of the conversion module) at the Dr12V port is transmitted to the driving end of the MOS tube Q25, thereby turning on the parallel output MOS tube Q25 and forming an isolated driving signal.

[0040] In this embodiment, the conversion circuit is electrically connected to the capacitor C36, the resistor R80, the resistor R84, the S port of the MOS tube Q25, the control circuit and the voltage output unit. Specifically, the conversion circuit includes a common mode inductor T1, the port 1 of the common mode inductor T1 is electrically connected to the cathode of the diode D17 and the control circuit, and the anode of the diode D17 is also electrically connected to the control circuit, while the port 2 of the common mode inductor T1 is electrically connected to the capacitor C34, the capacitor C36 and the resistor R84, and the capacitor C34 is grounded, the port 3 of the common mode inductor T1 is electrically connected to the capacitor EC2, the capacitor C38 and the voltage output unit, and the capacitor EC2 and the capacitor C38 are connected in parallel, and the port 4 of the common mode inductor T1 is electrically connected to the first parallel loop, the resistor R80 and the S port of the MOS tube Q25 through the diode.

[0041] Furthermore, the first parallel circuit includes capacitor EC1, capacitor C35 and a diode. Capacitor EC1, capacitor C35 and the diode are connected in parallel with each other, and capacitor EC1, capacitor C35 and the diode are electrically connected to capacitor C36 and resistor R84.

[0042] In the specific implementation process, the common mode inductor T1 is selected as the MSD1278-330 model, which is responsible for converting the input voltage into a stable output voltage. Capacitors EC1 and EC2 are inductors for energy storage and current smoothing, capacitors C34, C35 and C38 are used for filtering and voltage stabilization, and diode D17 is a Schottky diode for rectification.

[0043] Further, the control circuit includes a step-down IC chip U3 and a connector CN, port 1 and port 6 of the step-down IC chip U3 are both grounded, port 3 and port 4 of the step-down IC chip U3 are both electrically connected to the selection circuit through resistors, and port 2 of the step-down IC chip U3 is also electrically connected to the selection circuit, port 5 of the step-down IC chip U3 is electrically connected to the FB port, port 7 of the step-down IC chip U3 is electrically connected to capacitor C37, capacitor C37 is electrically connected to port 8 of the step-down IC chip U3, resistor R91 and port 1 of the common-mode inductor T1 and the cathode of diode D17, resistor R91 is electrically connected to capacitor C42, capacitor C42 is electrically connected to the anode of diode D17, and capacitor C42 is grounded.

[0044] Further, port 1 of connector CN is electrically connected to resistor R77 and resistor R79, port 2 of connector CN is electrically connected to resistor R78 and resistor R82, ports 3 and 4 of connector CN are both grounded, and resistor R77 and resistor R78 are both electrically connected to the 3.3V-MCU port, resistor R79 is electrically connected to the Addr0 port, and resistor R82 is electrically connected to the Addr1 port.

[0045] In the specific implementation process, the buck IC chip U3 is used to process the control signal, and the resistors R77, R79, R78 and R82 together form a voltage divider network, which can be used to generate different reference voltages. At the same time, the Addr0 port and the Addr1 port are both external input signals, that is, external input signals, which can be connected to the input end of the buck IC chip U3 after resistor voltage division.

[0046] Furthermore, the selection circuit includes a second parallel circuit and a resistor R92, the second parallel circuit is electrically connected to the resistor R86, the resistor R86 is electrically connected to the capacitor C40 and the port 2 of the buck IC chip U3, the resistor R92 is electrically connected to the AUX-EN port, the capacitor C41 and the port 3 of the buck IC chip U3, and the capacitor C40 and the capacitor C41 are both grounded.

[0047] Furthermore, the second parallel circuit includes two diodes connected in parallel, the anode of one diode is electrically connected to the B+ port, the other diode is electrically connected to the P+ port, and the cathodes of the two diodes connected in parallel are electrically connected to the resistor R86.

[0048] In the specific implementation process, the second parallel circuit is used to prevent reverse current, and the resistor R86, the resistor R92 and the capacitor C40, the capacitor C41 together form a filter for smoothing the input voltage.

[0049] Further, the voltage output unit includes a 12VB port and a TP41 port, the 12VB port is electrically connected to the cathode of the diode D15, the anode of the diode D15 is electrically connected to the 12V+ port, the resistor R81, the resistor R87, the resistor R88, the capacitor C39 and the capacitor C38, while the resistor R87 and the capacitor C39 are connected in parallel to each other and are electrically connected to the 5-port of the step-down IC chip U3, and the resistor R87 is electrically connected to the resistor R95, the resistor R81, the resistor R88 and the resistor R95 are electrically connected to the TP41 port and the capacitor C38, while the resistor R81 and the resistor R88 are connected in parallel to each other.

[0050] In the specific implementation process, resistors R87 and R95 form a voltage divider network, and are connected to port 5 of the buck IC chip U3 through the FB port, which is used to monitor the output voltage and send the monitored voltage signal to the common mode inductor T1. At the same time, the TP41 port can be connected to other external display devices, such as displaying the status indication of the power supply.

[0051] That is to say, in the conversion module, the conversion module is suitable for the non-common ground BMS parallel MOS drive circuit, and through the built-in step-down IC chip U3, the 2-port battery input voltage of the step-down IC chip U3 is stepped down to 12V, and output at 12V. At the same time, through the common-mode inductor T1, the function of the transformer is realized, so that the output voltages of ports 2 and 4 and ports 1 and 3 of the common-mode inductor T1 satisfy a 1:1 relationship, thereby realizing a 12V isolated regulated power supply, that is, the isolated power supply Dr12V in the above-mentioned drive module.

[0052] This embodiment also provides a low-cost BMS isolation drive circuit implementation method, which uses a low-cost BMS isolation drive circuit solution described in the above embodiment.

[0053] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is limited by the attached embodiments and their equivalents.

Claims

1. A low-cost BMS isolation drive circuit solution, characterized in that: It includes a driving module and a conversion module, the driving module and the conversion module are connected in parallel with each other, and the driving module is used to connect with an external device and the conversion module to send an isolated driving signal, and the conversion module is used to output a 12V isolated regulated power supply; The driving module includes a signal processing unit and an output control unit, the conversion module includes a voltage processing unit and a voltage output unit, the signal processing unit is electrically connected to the output control unit and the voltage processing unit, and the voltage processing unit is electrically connected to the voltage output unit.

2. A low-cost BMS isolation drive circuit solution according to claim 1, characterized in that: The signal processing unit includes an input circuit and a processing circuit, the input circuit is electrically connected to the processing circuit, and the processing circuit is electrically connected to the output control unit and the voltage processing unit; The input circuit includes a transistor Q26, the base of the transistor Q26 is electrically connected to resistors R85 and R90, the emitter of the transistor Q26 is electrically connected to resistor R90, the collector of the transistor Q26 is electrically connected to the processing circuit, and the emitter of the transistor Q26 and the resistor R90 are both grounded, and the resistor R85 is electrically connected to the Para-DRV-MCU port.

3. A low-cost BMS isolation drive circuit solution according to claim 2, characterized in that: The processing circuit includes a photocoupler U2, port 1 of the photocoupler U2 is electrically connected to a 3.3V port via a resistor R81, port 2 of the photocoupler U2 is electrically connected to a collector of a transistor Q26, port 3 of the photocoupler U2 is electrically connected to a resistor R84, the resistor R84 is electrically connected to a capacitor C36 and a voltage processing unit, port 2 of the photocoupler U2 is electrically connected to a resistor R80 and a resistor R83, and both the resistor R80 and the resistor R83 are electrically connected to an output control unit, and the resistor R80 is electrically connected to a voltage processing unit, and the resistor R83 is electrically connected to the resistor R84 and the voltage processing unit via a capacitor C36.

4. A low-cost BMS isolation drive circuit solution according to claim 1, 2 or 3, characterized in that: The output control unit includes a MOS tube Q25, a G port of the MOS tube Q25 is electrically connected to a resistor R83 and a capacitor C36, an S port of the MOS tube Q25 is electrically connected to a voltage processing unit and a resistor R80, and a D port of the MOS tube Q25 is electrically connected to an AUXG port.

5. A low-cost BMS isolation drive circuit solution according to claim 4, characterized in that: The voltage processing unit includes a conversion circuit, a control circuit and a selection circuit. The conversion circuit is electrically connected to the capacitor C36, the resistor R80, the resistor R84, the S port of the MOS tube Q25, the control circuit and the voltage output unit. At the same time, the control circuit is electrically connected to the selection circuit, and the selection circuit is electrically connected to the voltage output unit. The conversion circuit includes a common-mode inductor T1, a port 1 of the common-mode inductor T1 is electrically connected to the cathode of the diode D17 and the control circuit, and the anode of the diode D17 is also electrically connected to the control circuit, and a port 2 of the common-mode inductor T1 is electrically connected to a capacitor C34, a capacitor C36 and a resistor R84, and the capacitor C34 is grounded, a port 3 of the common-mode inductor T1 is electrically connected to a capacitor EC2, a capacitor C38 and a voltage output unit, and the capacitor EC2 and the capacitor C38 are connected in parallel to each other, and a port 4 of the common-mode inductor T1 is electrically connected to the first parallel loop, the resistor R80 and the S port of the MOS tube Q25 through a diode; The first parallel circuit includes a capacitor EC1, a capacitor C35 and a diode. The capacitor EC1, the capacitor C35 and the diode are connected in parallel with each other. Meanwhile, the capacitor EC1, the capacitor C35 and the diode are electrically connected to the capacitor C36 and the resistor R84.

6. A low-cost BMS isolation drive circuit solution according to claim 5, characterized in that: The control circuit includes a buck IC chip U3 and a connector CN, the 1st port and the 6th port of the buck IC chip U3 are both grounded, the 3rd port and the 4th port of the buck IC chip U3 are both electrically connected to the selection circuit through a resistor, and the 2nd port of the buck IC chip U3 is also electrically connected to the selection circuit, the 5th port of the buck IC chip U3 is electrically connected to the FB port, the 7th port of the buck IC chip U3 is electrically connected to the capacitor C37, the capacitor C37 is electrically connected to the 8th port of the buck IC chip U3, the resistor R91 and the 1st port of the common mode inductor T1 and the cathode of the diode D17, the resistor R91 is electrically connected to the capacitor C42, the capacitor C42 is electrically connected to the anode of the diode D17, and the capacitor C42 is grounded; Port 1 of the connector CN is electrically connected to resistor R77 and resistor R79, port 2 of the connector CN is electrically connected to resistor R78 and resistor R82, ports 3 and 4 of the connector CN are both grounded, and resistor R77 and resistor R78 are both electrically connected to the 3.3V-MCU port, resistor R79 is electrically connected to the Addr0 port, and resistor R82 is electrically connected to the Addr1 port.

7. A low-cost BMS isolation drive circuit solution according to claim 6, characterized in that: The selection circuit includes a second parallel circuit and a resistor R92, the second parallel circuit is electrically connected to a resistor R86, the resistor R86 is electrically connected to a capacitor C40 and a port 2 of a buck IC chip U3, the resistor R92 is electrically connected to an AUX-EN port, a capacitor C41 and a port 3 of a buck IC chip U3, and the capacitor C40 and the capacitor C41 are both grounded.

8. A low-cost BMS isolation drive circuit solution according to claim 7, characterized in that: The second parallel circuit includes two diodes connected in parallel, the anode of one diode is electrically connected to the B+ port, the other diode is electrically connected to the P+ port, and the cathodes of the two diodes connected in parallel are electrically connected to the resistor R86.

9. A low-cost BMS isolation drive circuit solution according to claim 5, characterized in that: The voltage output unit includes a 12VB port and a TP41 port, the 12VB port is electrically connected to the cathode of the diode D15, the anode of the diode D15 is electrically connected to the 12V+ port, the resistor R81, the resistor R87, the resistor R88, the capacitor C39 and the capacitor C38, and the resistor R87 and the capacitor C39 are connected in parallel to each other and are electrically connected to the 5-port of the step-down IC chip U3, and the resistor R87 is electrically connected to the resistor R95, and the resistor R81, the resistor R88 and the resistor R95 are electrically connected to the TP41 port and the capacitor C38, and the resistor R81 and the resistor R88 are connected in parallel to each other.

10. A low-cost BMS isolation drive circuit implementation method, characterized in that: The implementation method uses a low-cost BMS isolation drive circuit solution as described in any one of claims 1-9.

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