High-voltage acquisition circuit of battery management system
By combining a voltage divider circuit and a high-voltage sampling control circuit with a linear optocoupler and a differential proportional operation circuit, the problems of high cost and poor common-mode immunity of traditional battery management system high-voltage acquisition circuits are solved, achieving low-cost and high-precision voltage acquisition.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- JIANGSU ZONGLANG HUANENG TECHNOLOGY CO LTD
- Filing Date
- 2025-05-26
- Publication Date
- 2026-05-08
AI Technical Summary
Traditional battery management systems have high-voltage acquisition circuits that are expensive and have poor common-mode immunity.
A voltage divider circuit and a high-voltage sampling control circuit, combined with a linear optocoupler and a differential proportional operation circuit, are used to replace integrated chips for signal acquisition.
It reduces circuit costs, improves common-mode immunity and signal accuracy, and achieves high-precision and high-reliability voltage acquisition.
Smart Images
Figure CN224217517U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of BMS technology, specifically a high-voltage acquisition circuit for a battery management system. Background Technology
[0002] The BMS system, or Battery Management System, is an indispensable core component of electric vehicles and energy storage systems. It acts as the central hub of the battery pack, responsible for comprehensively monitoring, managing, and maintaining battery modules to ensure safe and efficient battery operation and extend their lifespan. High data acquisition accuracy, signal-to-noise ratio, and enhanced stability enable accurate and stable high-voltage data acquisition circuitry for estimating State of Charge (SOC) and State of Harshness (SOH) and managing the safety of the power battery.
[0003] Currently, traditional battery management system high-voltage acquisition circuits include voltage divider modules, differential acquisition modules, ADC modules, isolation modules, and communication modules. The voltage divider module divides the high-voltage signal, then the differential acquisition module performs differential measurement and differential signal conditioning to form a sampling signal, which is then acquired by the ADC module's integrated chip. Finally, the signal is transmitted to the microcontroller via the isolation module and communication module. This acquisition circuit uses integrated chips, which are expensive, leading to high costs, and also have poor common-mode noise immunity. Utility Model Content
[0004] The technical problem to be solved by this utility model is to provide a high-voltage acquisition circuit for a battery management system, which has low cost and good common-mode immunity.
[0005] To solve the above problems, the following technical solutions are provided:
[0006] The high-voltage acquisition circuit of the battery management system of this utility model is characterized by the following:
[0007] The voltage divider circuit and high-voltage sampling control circuit are used to collect the battery voltage and generate a sampling signal HV_V;
[0008] A linear optocoupler and differential proportional operation circuit are adapted and connected to the voltage divider circuit and high voltage sampling control circuit to receive the sampling signal HV_V and form the signal HV_V_AD.
[0009] The main control unit is adapted and connected to the voltage divider circuit, the high-voltage sampling control circuit, the linear optocoupler, and the differential proportional operation circuit. The main control unit sends control signals to the voltage divider circuit and the high-voltage sampling control circuit to control the high-voltage sampling control circuit to generate a sampling signal HV_V; the main control unit receives the signal HV_V_AD.
[0010] The voltage divider circuit and high-voltage sampling control circuit include an optocoupler U1. The controlled terminal of the optocoupler U1 is connected to the battery to generate the sampling signal HV_V. The control terminal of the optocoupler U1 is connected to the main control unit to receive the control signal and control the controlled terminal of the optocoupler U1 to generate the sampling signal HV_V.
[0011] The controlled terminal of the optocoupler U1 contains a photosensitive switch. One end of the photosensitive switch is connected in series with two resistors to receive the high-voltage signal HV. The other end of the photosensitive switch is connected to one end of resistor R9, and the other end of resistor R9 is grounded through resistor R12. The control terminal of the optocoupler U1 contains a light-emitting diode (LED) for driving the photosensitive switch to conduct. The anode of the LED is connected in series with a resistor and then connected to the power supply VCC. The cathode of the LED is connected to the collector of transistor Q. The base of transistor Q is connected in series with a resistor and then used to receive the control signal. The base of transistor Q is connected in series with another resistor and then grounded. The emitter of transistor Q is grounded. After the control signal is transmitted, transistor Q conducts, the LED conducts and produces light, and the photosensitive switch conducts, forming the sampling signal HV_V.
[0012] There are multiple photosensitive switches. One end of each photosensitive switch is connected in series with two resistors to receive different high-voltage signals HV. The other end of each photosensitive switch is connected to one end of the resistor R9 that is not connected to the resistor R12. Each photosensitive switch corresponds to a light-emitting diode, and each light-emitting diode corresponds to a transistor Q. The main control unit sends a control signal to the corresponding transistor Q to generate the corresponding sampling signal HV_V, thus forming multi-channel sampling.
[0013] The linear optocoupler and differential proportional operation circuit includes a linear optocoupler U2. The Vin pin on the input side of the linear optocoupler U2 is used to receive the sampling signal HV_V, and the Vin pin on the input side of the linear optocoupler U2 is connected to one end of capacitor C6 and capacitor C7 respectively, and the other end of capacitor C6 and capacitor C7 is grounded. The SHIN pin on the input side of the linear optocoupler U2 is grounded. The VOUT1 pin and VOUT2 pin on the output side of the linear optocoupler U2 form the signal HV_V_AD after passing through a differential circuit.
[0014] The differential circuit includes operational amplifiers U3B and U3A. The output pin VOUT1 of the linear optocoupler U2 is connected to one end of resistor R18. The other end of resistor R18 is connected to the non-inverting input of operational amplifier U3B, one end of resistor R20, and one end of capacitor C9. The other ends of resistor R20 and capacitor C9 are both grounded. The output pin VOUT2 of the linear optocoupler U2 is connected to one end of resistor R15 and one end of resistor R16. The other end of resistor R15 is connected to the inverting input of operational amplifier U3A, and the other end of resistor R16 is connected to the inverting input of operational amplifier U3B. The output of operational amplifier U3B is connected to capacitor C2... One end of capacitor C2, one end of resistor R14, and one end of resistor R17 are connected to the inverting input of operational amplifier U3B, forming negative feedback. The other end of resistor R17 is connected to the non-inverting input of operational amplifier U3A, one end of resistor R19, and one end of capacitor C8. The other ends of resistor R19 and capacitor C8 are grounded. The output of operational amplifier U3A is connected to one end of capacitor C1 and one end of resistor R13. The other ends of capacitor C1 and resistor R13 are connected to the inverting input of operational amplifier U3A, forming negative feedback. The output of operational amplifier U3A forms the signal HV_V_AD.
[0015] The above approach has the following advantages:
[0016] The high-voltage acquisition circuit of the battery management system of this invention uses a linear optocoupler and a differential proportional operational amplifier circuit to receive the sampled signal HV_V and generate the signal HV_V_AD. Compared with integrated chips, the linear optocoupler and differential proportional operational amplifier circuit are cheaper, resulting in a lower overall circuit cost. Furthermore, the linear optocoupler has a high common-mode rejection ratio, thereby improving the circuit's common-mode transient immunity. Attached Figure Description
[0017] Figure 1 This is a topology diagram of the high-voltage acquisition circuit structure of the battery management system of this utility model;
[0018] Figure 2 This is a schematic diagram of the voltage divider circuit and the high-voltage sampling control circuit in the high-voltage acquisition circuit of the battery management system of this utility model;
[0019] Figure 3 This is a schematic diagram of the linear optocoupler and differential proportional operation circuit in the high-voltage acquisition circuit of the battery management system of this utility model. Detailed Implementation
[0020] The present invention will be further described in detail below with reference to the accompanying drawings.
[0021] like Figure 1 As shown, the high-voltage acquisition circuit of the battery management system of this utility model includes a power input interface, a power conversion circuit, an isolated power conversion circuit, a voltage divider circuit and a high-voltage sampling control circuit, a linear optocoupler and a differential proportional operation circuit, and a main control unit. The power conversion circuit is connected to an external power source (which can be the battery of the battery management system or an additional power source) through the power input interface. The power conversion circuit is connected to the power supply VCC to supply the output side of the linear optocoupler of the voltage divider circuit, the high-voltage sampling control circuit, the linear optocoupler and the differential proportional operation circuit, and the main control unit. It is used to convert the external power supply into power supply VCC for use by the output side of the linear optocoupler of the voltage divider circuit, the high-voltage sampling control circuit, the linear optocoupler and the differential proportional operation circuit, and the main control unit. The power supply VCC is converted into power supply IS_VCC through the power conversion circuit for use by the input side of the linear optocoupler in the linear optocoupler and the differential proportional operation circuit. The voltage divider circuit and high-voltage sampling control circuit are connected to the linear optocoupler, differential proportional operation circuit, and main control unit. The voltage divider circuit and high-voltage sampling control circuit are used to acquire the battery voltage and generate a sampling signal HV_V. The linear optocoupler and differential proportional operation circuit are used to receive the sampling signal HV_V and generate the signal HV_V_AD. The main control unit sends a control signal to the voltage divider circuit and high-voltage sampling control circuit, controlling the high-voltage sampling control circuit to generate the sampling signal HV_V. The sampling signal HV_V is then processed by the linear optocoupler and differential proportional operation circuit to generate the signal HV_V_AD, which is input to the main control unit. The main control unit receives the signal HV_V_AD.
[0022] The main control unit is a microcontroller. Its specific model and peripheral circuits can be selected by those skilled in the art as needed, and are existing technologies, so they will not be described in detail here.
[0023] like Figure 2As shown, in this embodiment, the voltage divider circuit and high-voltage sampling control circuit include an optocoupler U1. The controlled terminal of the optocoupler U1 is connected to the battery to generate a sampling signal HV_V. The control terminal of the optocoupler U1 is connected to the main control unit to receive control signals and control the controlled terminal of the optocoupler U1 to generate the sampling signal HV_V. The controlled terminal of the optocoupler U1 includes a photosensitive switch. One end of the photosensitive switch is connected in series with two resistors to receive the high-voltage signal HV. The other end of the photosensitive switch is connected to one end of resistor R9, and the other end of resistor R9 is grounded through resistor R12. The control terminal of the optocoupler U1 includes a light-emitting diode (LED) to drive the photosensitive switch to conduct. The anode of the LED is connected in series with a resistor and then connected to the power supply VCC. The cathode of the LED is connected to the collector of transistor Q. The base of transistor Q is connected in series with a resistor to receive control signals. The base of transistor Q is connected in series with another resistor and then grounded. The emitter of transistor Q is grounded. After the control signal is transmitted, transistor Q turns on, the LED turns on and emits light, and the photosensitive switch turns on, forming a sampling signal HV_V. There are multiple photosensitive switches. One end of each photosensitive switch is connected in series with two resistors to receive different high-voltage signals HV. The other end of each photosensitive switch is connected to one end of resistor R9 (which is not connected to resistor R12). Each photosensitive switch corresponds to one LED, and each LED corresponds to one transistor Q. The main control unit sends a control signal to the corresponding transistor Q, thereby generating the corresponding sampling signal HV_V, forming multi-channel sampling.
[0024] like Figure 2 As shown, in this embodiment, the optocoupler U1 is model AQW216A, and the phototransistor is a phototransistor containing two phototransistors and two light-emitting diodes (LEDs), corresponding to two high-voltage signals HV, namely high-voltage signal HV1 and high-voltage signal HV2. One of the phototransistors is connected to a multi-channel high-voltage connector after a series resistor R2 and R1 to receive high-voltage signal HV1. The other phototransistor is connected to a multi-channel high-voltage connector after a series resistor R6 and R5 to receive high-voltage signal HV2. The cathode of one of the LEDs is connected to the collector of transistor Q2, the emitter of transistor Q2 is grounded, and the base of transistor Q2 is connected to one end of resistor R11 and resistor R8. The other end of resistor R11 is grounded, and the other end of resistor R8 is connected to the main control unit to receive the control signal PP- generated by the main control unit. The cathode of another LED is connected to the collector of transistor Q1, the emitter of transistor Q1 is grounded, and the base of transistor Q1 is connected to one end of resistors R7 and R10. The other end of resistor R10 is grounded, and the other end of resistor R7 is connected to the main control unit to receive the control signal LP- generated by the main control unit.
[0025] like Figure 3As shown, the linear optocoupler and differential proportional operational circuit includes a linear optocoupler U2. The Vin pin on the input side of the linear optocoupler U2 is used to receive the sampling signal HV_V. The Vin pin on the input side of the linear optocoupler U2 is connected to one end of capacitors C6 and C7, respectively, and the other ends of capacitors C6 and C7 are grounded. The SHIN pin on the input side of the linear optocoupler U2 is grounded. The VOUT1 pin and VOUT2 pin on the output side of the linear optocoupler U2 form the signal HV_V_AD after passing through the differential circuit. The differential circuit includes operational amplifiers U3B and U3A. The VOUT1 pin on the output side of the linear optocoupler U2 is connected to one end of resistor R18. The other end of resistor R18 is connected to the non-inverting input of operational amplifier U3B, one end of resistor R20, and one end of capacitor C9. The other ends of resistor R20 and capacitor C9 are both grounded. The output pin VOUT2 of linear optocoupler U2 is connected to one end of resistor R15 and one end of resistor R16. The other end of resistor R15 is connected to the inverting input of operational amplifier U3A, and the other end of resistor R16 is connected to the inverting input of operational amplifier U3B. The output of operational amplifier U3B is connected to one end of capacitor C2, one end of resistor R14, and one end of resistor R17. The other ends of capacitor C2 and resistor R14 are both connected to the inverting input of operational amplifier U3B, forming negative feedback. The other end of resistor R17 is connected to the non-inverting input of operational amplifier U3A, one end of resistor R19, and one end of capacitor C8. The other ends of resistor R19 and capacitor C8 are both grounded. The output of operational amplifier U3A is connected to one end of capacitor C1 and one end of resistor R13. The other ends of capacitor C1 and resistor R13 are both connected to the inverting input of operational amplifier U3A, forming negative feedback. The operational amplifier U3A outputs a signal HV_V_AD.
[0026] The high-voltage acquisition circuit of this battery management system employs a linear optocoupler with a high common-mode rejection ratio, improving common-mode transient immunity and providing the accuracy and stability required for precise monitoring of the DC bus voltage in high-noise environments, while also increasing the input voltage range. The voltage divider network of the voltage divider circuit and the high-voltage sampling control circuit can be designed with higher input impedance to reduce the DC bus current load. Furthermore, the linear optocoupler solution is cost-effective. In addition, the differential circuit can adjust the voltage acquisition range, selecting the minimum to maximum voltage range, compressing the effective voltage range for acquisition, and further improving voltage acquisition accuracy.
[0027] The advantages of the high-voltage acquisition circuit of the battery management system of this utility model are that it achieves high-precision and high-reliability acquisition of high-voltage battery voltage; high input impedance; high common-mode transient immunity, high gain accuracy and stability; and adjustable acquisition voltage range.
Claims
1. A high-voltage acquisition circuit for a battery management system, characterized in that, include: The voltage divider circuit and high-voltage sampling control circuit are used to collect the battery voltage and generate a sampling signal HV_V; A linear optocoupler and differential proportional operation circuit are adapted and connected to the voltage divider circuit and high voltage sampling control circuit to receive the sampling signal HV_V and form the signal HV_V_AD. The main control unit is adapted and connected to the voltage divider circuit, the high-voltage sampling control circuit, the linear optocoupler, and the differential proportional operation circuit. The main control unit sends control signals to the voltage divider circuit and the high-voltage sampling control circuit to control the high-voltage sampling control circuit to generate a sampling signal HV_V; the main control unit receives the signal HV_V_AD.
2. The high-voltage acquisition circuit of the battery management system as described in claim 1, characterized in that, The voltage divider circuit and high-voltage sampling control circuit include an optocoupler U1. The controlled terminal of the optocoupler U1 is connected to the battery to generate the sampling signal HV_V. The control terminal of the optocoupler U1 is connected to the main control unit to receive the control signal and control the controlled terminal of the optocoupler U1 to generate the sampling signal HV_V.
3. The high-voltage acquisition circuit of the battery management system as described in claim 2, characterized in that, The controlled terminal of the optocoupler U1 contains a photosensitive switch. One end of the photosensitive switch is connected in series with two resistors to receive the high-voltage signal HV. The other end of the photosensitive switch is connected to one end of resistor R9, and the other end of resistor R9 is grounded through resistor R12. The control terminal of the optocoupler U1 contains a light-emitting diode (LED) for driving the photosensitive switch to conduct. The anode of the LED is connected in series with a resistor and then connected to the power supply VCC. The cathode of the LED is connected to the collector of transistor Q. The base of transistor Q is connected in series with a resistor and then used to receive the control signal. The base of transistor Q is connected in series with another resistor and then grounded. The emitter of transistor Q is grounded. After the control signal is transmitted, transistor Q conducts, the LED conducts and produces light, and the photosensitive switch conducts, forming the sampling signal HV_V.
4. The high-voltage acquisition circuit of the battery management system as described in claim 3, characterized in that, There are multiple photosensitive switches. One end of each photosensitive switch is connected in series with two resistors to receive different high-voltage signals HV. The other end of each photosensitive switch is connected to one end of the resistor R9 that is not connected to the resistor R12. Each photosensitive switch corresponds to a light-emitting diode, and each light-emitting diode corresponds to a transistor Q. The main control unit sends a control signal to the corresponding transistor Q to generate the corresponding sampling signal HV_V, thus forming multi-channel sampling.
5. The high-voltage acquisition circuit of the battery management system as described in claim 1, characterized in that, The linear optocoupler and differential proportional operation circuit includes a linear optocoupler U2. The Vin pin on the input side of the linear optocoupler U2 is used to receive the sampling signal HV_V, and the Vin pin on the input side of the linear optocoupler U2 is connected to one end of capacitor C6 and capacitor C7 respectively, and the other end of capacitor C6 and capacitor C7 is grounded. The SHIN pin on the input side of the linear optocoupler U2 is grounded. The VOUT1 pin and VOUT2 pin on the output side of the linear optocoupler U2 form the signal HV_V_AD after passing through a differential circuit.
6. The high-voltage acquisition circuit of the battery management system as described in claim 5, characterized in that, The differential circuit includes operational amplifiers U3B and U3A. The output pin VOUT1 of the linear optocoupler U2 is connected to one end of resistor R18. The other end of resistor R18 is connected to the non-inverting input of operational amplifier U3B, one end of resistor R20, and one end of capacitor C9. The other ends of resistor R20 and capacitor C9 are both grounded. The output pin VOUT2 of the linear optocoupler U2 is connected to one end of resistor R15 and one end of resistor R16. The other end of resistor R15 is connected to the inverting input of operational amplifier U3A, and the other end of resistor R16 is connected to the inverting input of operational amplifier U3B. The output of operational amplifier U3B is connected to capacitor C2... One end of capacitor C2, one end of resistor R14, and one end of resistor R17 are connected to the inverting input of operational amplifier U3B, forming negative feedback. The other end of resistor R17 is connected to the non-inverting input of operational amplifier U3A, one end of resistor R19, and one end of capacitor C8. The other ends of resistor R19 and capacitor C8 are grounded. The output of operational amplifier U3A is connected to one end of capacitor C1 and one end of resistor R13. The other ends of capacitor C1 and resistor R13 are connected to the inverting input of operational amplifier U3A, forming negative feedback. The output of operational amplifier U3A forms the signal HV_V_AD.