Voltage following module, heat management controller water pump driving circuit and vehicle

Abstract

The invention relates to a voltage following module, a heat management controller water pump driving circuit and a vehicle. The voltage following module comprises an operational amplifier U1A, an operational amplifier U1B, resistors R1 to R6 and capacitors C1 to C3. The in-phase input end of the operational amplifier U1A is connected to a voltage P5VNor through a resistor R3; the anti-phase input end of the operational amplifier U1A is connected to a voltage P5VUp through a resistor R4, and the anti-phase input end of the operational amplifier U1A is also connected with the output end of the operational amplifier U1A through a resistor R6; the output end of the operational amplifier U1A is also connected to a voltage P5VUp through a resistor R2 and a resistor R1; and the reverse input end of the operational amplifier U1B is connected with the output end of the operational amplifier U1B to form a voltage follower structure. The problem of current sampling deviation caused by a voltage follower in a water pump driving circuit of an existing automobile heat management controller is solved.

Description

Technical Field

[0001] This invention relates to the field of thermal management controller water pump drive circuit technology, specifically to a voltage follower module, a thermal management controller water pump drive circuit, and a vehicle. Background Technology

[0002] With the booming development of the new energy vehicle industry, the continuous iteration of thermal management system technology for new energy vehicles has become a key link in improving vehicle performance and energy efficiency. Its core purpose is to achieve precise internal matching of heat and cooling demand in each circuit, optimize energy consumption, and efficiently realize cooling and heating functions by reducing battery energy consumption, thereby improving the overall performance and range of new energy vehicles.

[0003] The thermal management circuits of pure electric vehicles mainly encompass the automotive air conditioning circuit (cockpit thermal management circuit), battery thermal management circuit, and motor thermal management circuit. With continuous technological advancements, leading OEMs have gradually developed second- and third-generation technologies in motor thermal management, battery thermal management, and cabin thermal management. Each generation of technology updates places higher demands on software and hardware integration, making continuous improvement in integration a significant trend.

[0004] During this technological evolution, the pump drive method of the thermal management controller has undergone significant changes. There has been a gradual transition from the previous pump drive minimum system chip to a pure pre-drive chip, replacing the original pump drive minimum system chip. Because the pump drive minimum system chip has been eliminated, the entire motor drive algorithm previously located within it needs to be transferred to the main MCU (the core control unit of the entire electric drive system). This shift presents new challenges to the circuit design of the thermal management controller, especially the voltage follower section in the pump drive circuit.

[0005] In the voltage follower design of the water pump drive circuit in existing automotive thermal management controllers, there is a critical issue affecting system performance. After processing by the voltage follower, the reference voltage P2V5_VREF = (P5V_Up - U) / 2. The MCU's ADC supply voltage is P5V_Up, and it uses 1 / 2 (P5V_Up) as the zero-current criterion. However, the actual voltage value acquired at zero current is (P5V_Up - U) / 2, which leads to a deviation in the acquired current value.

[0006] This current sampling deviation can cause a series of serious problems. First, it affects the accuracy of the current closed-loop control, causing unstable pump speed and, in extreme cases, even pump shutdown, affecting the normal operation of the thermal management system. Second, the current sampling deviation lowers the current protection threshold, leading to situations where the actual current exceeds the sampled current. When the current exceeds the overcurrent protection threshold, the system may fail to trigger the protection mechanism, potentially causing component damage, increasing maintenance costs and safety hazards. Furthermore, the sampling current error also increases the synchronization deviation between current control and rotor position, increasing copper and iron losses, reducing system efficiency, and affecting the overall performance and energy utilization rate of new energy vehicles. Therefore, it is necessary to develop a new voltage follower module, thermal management controller, water pump drive circuit, and vehicle. Summary of the Invention

[0007] The purpose of this invention is to provide a voltage follower module, a thermal management controller water pump drive circuit, and a vehicle to solve the current sampling deviation problem caused by the voltage follower in the existing automotive thermal management controller water pump drive circuit.

[0008] In a first aspect, the present invention provides a voltage follower module for a thermal management controller water pump drive circuit, comprising an operational amplifier U1A, an operational amplifier U1B, resistors R1 to R6, and capacitors C1 to C3. The non-inverting input of operational amplifier U1A is connected to voltage P5V_Nor via resistor R3, and is also grounded via resistor R5. The inverting input of operational amplifier U1A is connected to voltage P5V_Up via resistor R4, and is also connected to the output of operational amplifier U1A via resistor R6. The positive power supply of operational amplifier U1A is connected to voltage P5V_Up, and is also grounded via capacitor C1. The negative power supply of operational amplifier U1A is grounded. The output of operational amplifier U1A is also connected to voltage P5V_Up via resistors R2 and R1. The non-inverting input terminal of the operational amplifier U1B is connected to the junction of resistors R2 and R1, and the inverting input terminal of the operational amplifier U1B is connected to the output terminal of the operational amplifier U1B, forming a voltage follower structure; the output terminal of the operational amplifier U1B is grounded through capacitor C3, and the output terminal of the operational amplifier U1B is also connected to voltage P2V5_VREF. The capacitor C2 is connected in parallel with the resistor R2.

[0009] Optionally, the resistance values ​​of resistors R3, R4, R5, and R6 are equal.

[0010] Optionally, the resistance values ​​of resistor R1 and resistor R2 are equal.

[0011] Optionally, the output voltage of the operational amplifier U1A is P5V_Nor - P5V_Up; the output voltage of the operational amplifier U1B is: 1 / 2[P5V_Up - (P5V_Nor - P5V_Up)] = 1 / 2(P5V_Up).

[0012] Secondly, the thermal management controller water pump drive circuit of the present invention adopts the voltage follower module as described in the present invention.

[0013] Thirdly, the vehicle described in this invention employs the water pump drive circuit of the automotive thermal management controller as described in this invention.

[0014] The beneficial effects of this invention are: (1) The voltage follower module for the water pump drive circuit of the thermal management controller of the present invention, through the specific connection of operational amplifiers U1A and U1B and resistors R1-R6 and capacitors C1-C3, and with resistors R3, R4, R5, and R6 having equal resistance values, and resistors R1 and R2 having equal resistance values, makes the output voltage of operational amplifier U1B 1 / 2 (P5V_Up), effectively compensating for the voltage difference caused by factors such as switching, and making the 0 current voltage used by the MCU for judgment consistent with the actual 0 current sampling voltage. This eliminates the current sampling deviation, significantly improves the accuracy of current closed-loop control, ensures that the water pump can operate stably and accurately, and avoids the adverse effects caused by unstable speed or shutdown.

[0015] (2) The voltage follower module of the present invention enables the sampled current to accurately reflect the actual current value through precise voltage processing and compensation. In this way, when the actual current exceeds the overcurrent protection threshold, the system can trigger the protection mechanism in a timely and accurate manner, effectively avoiding damage to components due to overcurrent, greatly enhancing the reliability of overcurrent protection, thereby improving the reliability of the entire thermal management controller water pump drive system, and reducing maintenance costs and safety hazards.

[0016] (3) The voltage follower module of the present invention improves the current sampling accuracy, enabling better synchronization between current control and rotor position, reducing unnecessary energy loss and lowering copper and iron losses. At the same time, stable and accurate water pump operation also helps the thermal management system to achieve more efficient internal matching of heat and cold, further improving energy efficiency, optimizing the overall operating performance of the system, and enhancing the overall performance and energy utilization rate of new energy vehicles. Attached Figure Description

[0017] Figure 1 This is a circuit diagram of the power supply module in the water pump drive circuit of the automotive thermal management controller described in this application embodiment; Figure 2 This is a circuit diagram of the drive circuit in the water pump drive circuit of the automotive thermal management controller described in the embodiments of this application; Figure 3 This is a circuit diagram of the differential amplifier circuit in the water pump drive circuit of the automotive thermal management controller described in the embodiments of this application; Figure 4 This is a circuit diagram of a commonly used voltage follower; Figure 5 This is a circuit diagram of the voltage follower module in an embodiment of this application. Detailed Implementation

[0018] The embodiments of the present invention will be described below with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are only for illustrating the present invention and not for limiting the scope of protection of the present invention.

[0019] To enable those skilled in the art to better understand the present application, the application scenarios of the present application are described below.

[0020] like Figures 1 to 4 As shown, this is a power supply module, drive module, differential amplifier module, and voltage follower for a single water pump motor in the current thermal management controller. The water pump motor is a brushless DC motor, and the drive method adopts the sensorless FOC (field-oriented control, also known as vector control) algorithm.

[0021] like Figure 1 The diagram shows the circuit diagram of the power supply module. The DC-DC converter is used to convert 12V voltage to 5V voltage (i.e., voltage P5V_Nor) to power the ADC of the MCU, and to supply power to the sampling part of the water pump circuit through a switch Q1. The function of switch Q1 is to meet the low power consumption requirements of the thermal management controller (i.e., current less than 1mA in sleep mode). Figure 1 The DO_Logic_Power_Switch signal is a low-power switching signal output by the MCU. Turning on switch Q1 provides 5V power to the subsequent differential amplifier modules, etc.

[0022] like Figure 2The diagram shows the circuit of the drive module, which includes MOSFETs Q2 to Q7, resistors R7 to R15, and capacitors C4 to C6. The gates of the six MOSFETs are driven by a pure pre-drive chip (not shown in the diagram). HS_U, HS_V, and HS_W are all connected to the pure pre-drive chip to collect the back electromotive force of the water pump coil, thereby obtaining the position of the water pump rotor. EXT_Output_U, EXT_Output_V, and EXT_Output_W are the drive signals of the water pump, which are connected one-to-one with the U, V, and W phases of the water pump, respectively. Resistors R9, R10, and R14 are sampling resistors. U_Current_Sense_P and U_Current_Sense_N are the voltages across resistor R9, V_Current_Sense_P and V_Current_Sense_N are the voltages across resistor R10, and BUS_Current_Sense_P and BUS_Current_Sense_N are the voltages across resistor R14. By performing differential calculations on the voltages across the sampling resistors (including R9, R10, and R14), the U and V currents and the bus current can be obtained. The pump speed information can be obtained by sampling the current, and the bus current can also be used for overcurrent protection, stall protection, and no-load protection of the pump. HBD_U, HBD_V, HBD_W, LBD_U, LBD_V, and LBD_W are the drive signals output by the pure pre-driver chip, used to control the turning on or off of the corresponding MOSFETs.

[0023] like Figure 3 As shown, this circuit is a differential amplifier module, including a first differential amplifier submodule, a second differential amplifier submodule, and a third differential amplifier submodule.

[0024] The first differential amplifier submodule includes resistors R17 to R21, capacitors C7 to C10, and operational amplifier U3A. The specific connection relationship is as follows: The non-inverting input of operational amplifier U3A is connected to voltage P2V5_VREF via resistor R17. The non-inverting input of operational amplifier U3A is also grounded via resistor R18 and capacitor C8. The connection point of resistor R18 and capacitor C8 is... Figure 2 The connection point of resistor R13 and capacitor C6 is connected. The inverting input terminal of operational amplifier U3A is grounded through resistor R20 and capacitor C9, and the connection point of resistor R20 and capacitor C9 is connected to... Figure 2The connection point of resistor R15 and capacitor C6 is connected. The positive power supply terminal of operational amplifier U3A is connected to voltage P5V_Up, and is also grounded via capacitor C7. The negative power supply terminal of operational amplifier U3A is grounded. The inverting input terminal of operational amplifier U3A is connected to its output terminal via resistor R21, and is also grounded via resistor R19 and capacitor C10. The connection point of resistor R19 and capacitor C10 is the bus current acquisition point (i.e., AI_BUS_Current_ADC, connected to the MCU's ADC).

[0025] The second differential amplifier submodule includes resistors R23 to R27, capacitors C13 to C16, and operational amplifier U2A. The specific connection relationship is as follows: The non-inverting input of operational amplifier U2A is connected to voltage P2V5_VREF through resistor R23. The non-inverting input of operational amplifier U2A is also grounded through resistor R24 ​​and capacitor C14. The connection point of resistor R24 ​​and capacitor C14 is... Figure 2 The connection point of resistor R7 and capacitor C5 is connected. The inverting input terminal of operational amplifier U2A is grounded through resistor R26 and capacitor C15, and the connection point of resistor R26 and capacitor C15 is connected to... Figure 2 The connection point of resistor R11 and capacitor C5 is connected. The positive power supply terminal of operational amplifier U2A is connected to voltage P5V_Up, and the positive power supply terminal of operational amplifier U2A is also grounded through capacitor C13. The negative power supply terminal of operational amplifier U2A is grounded. The inverting input terminal of operational amplifier U2A is connected to the output terminal of operational amplifier U2A through resistor R27, and the output terminal of operational amplifier U2A is also grounded through resistor R25 and capacitor C16. The connection point of resistor R25 and capacitor C16 is the V-phase current acquisition point (i.e., AI_V_Current_ADC, connected to the MCU's ADC).

[0026] The third differential amplifier submodule includes resistors R28 to R32, capacitors C17 to C19, and operational amplifier U3B. The specific connection relationship is as follows: The non-inverting input of operational amplifier U3B is connected to voltage P2V5_VREF via resistor R28. The non-inverting input of operational amplifier U3B is also grounded via resistor R29 and capacitor C17. The connection point of resistor R29 and capacitor C17 is... Figure 2 The connection point of resistor R8 and capacitor C4 is connected. The inverting input terminal of operational amplifier U3B is grounded through resistor R31 and capacitor C18, and the connection point of resistor R31 and capacitor C18 is connected to... Figure 2The connection point of resistor R12 and capacitor C4 is connected. The inverting input terminal of operational amplifier U3B is connected to the output terminal of operational amplifier U3B via resistor R32. The output terminal of operational amplifier U3B is also grounded via resistor R30 and capacitor C19. The connection point of resistor R30 and capacitor C19 is the U-phase current acquisition point (i.e., AI_U_Current_ADC, which is connected to the MCU's ADC).

[0027] By differentially amplifying the voltage across the sampling resistors (including resistors R9, R10, and R14) and then feeding the voltage value back to the MCU's ADC, the magnitude of the phase current and bus current can be obtained through calculation given the known resistance values ​​of the sampling resistors.

[0028] like Figure 4 As shown, this circuit is a common voltage follower, including operational amplifier U2B, resistor R16, resistor R22, capacitor C11, and capacitor C12. The specific connection relationship is as follows: The non-inverting input of operational amplifier U2B is connected to voltage P5V_Up via resistor R16, and is also grounded via resistor R22 and capacitor C11. The inverting input of operational amplifier U2B is connected to its output, which is grounded via capacitor C12 and also connected to voltage P2V5_VREF. The resistance ratio of resistors R16 and R22 is 1:1, thus generating a voltage of 0.5 * P5V_Up, which is used as the bias voltage for operational amplifier U2B.

[0029] like Figure 1 As shown, due to the action of switch Q1, a certain voltage difference will be generated between voltage P5V_Up and voltage P5V_Nor. Let this voltage difference be U. Figure 4 After processing by the voltage follower shown, the reference voltage P2V5_VREF = (P5V_Up - U) / 2. The MCU's ADC supply voltage is P5V_Up, and it uses 1 / 2 (P5V_Up) as the basis for zero current judgment. However, the actual zero current is the sampled voltage value of (P5V_Up - U) / 2, which will cause a deviation in the sampled current value. This deviation will affect the accuracy of the current closed-loop control, causing unstable pump speed, and in severe cases, even pump shutdown. At the same time, it will lower the current protection threshold, meaning that if the actual current is greater than the sampled current, the protection will not be triggered when the current exceeds the overcurrent protection threshold, thus causing component damage. In addition, the sampling current error will also increase the synchronization deviation between current control and rotor position, increase copper loss and iron loss, and reduce system efficiency.

[0030] like Figure 5 As shown in the embodiments of this application, in order to solve the above problems, a new voltage follower module is provided for the water pump drive module of the thermal management controller. The voltage follower module includes operational amplifier U1A, operational amplifier U1B, resistors R1 to R6, and capacitors C1 to C3, with the following connection relationship: The non-inverting input of operational amplifier U1A is connected to voltage P5V_Nor through resistor R3, and is also grounded through resistor R5. The inverting input of operational amplifier U1A is connected to voltage P5V_Up through resistor R4, and is also connected to the output of operational amplifier U1A through resistor R6. The positive power supply of operational amplifier U1A is connected to voltage P5V_Up, and is also grounded through capacitor C1. The negative power supply of operational amplifier U1A is grounded. The output of operational amplifier U1A is also connected to voltage P5V_Up through resistors R2 and R1. The non-inverting input of operational amplifier U1B is connected to the junction of resistors R2 and R1, and the inverting input of operational amplifier U1B is connected to its output, forming a voltage follower structure. The output of operational amplifier U1B is grounded through capacitor C3, and is also connected to voltage P2V5_VREF. Capacitor C2 is connected in parallel with resistor R2.

[0031] That is, based on the conventional voltage follower module, resistors R3, R4, R5, and R6 are added, and the resistance values ​​of resistors R3, R4, R5, and R6 are equal. In addition, the resistance values ​​of resistors R1 and R2 are also equal.

[0032] Among them, the output voltage of operational amplifier U1A is P5V_Nor-P5V_Up, and the output voltage of operational amplifier U1B is: 1 / 2[P5V_Up-(P5V_Nor-P5V_Up)]=1 / 2(P5V_Up).

[0033] In this embodiment, by improving the conventional voltage follower module, the voltage difference caused by switch Q1 is effectively compensated, so that the 0 current voltage used by the MCU for judgment is consistent with the actual 0 current sampling voltage, thereby effectively avoiding many problems existing in the conventional voltage follower module.

[0034] Figure 4 TP1 and Figure 5 TP2 in the diagram is the test point.

[0035] In this embodiment of the application, a thermal management controller water pump drive circuit adopts a voltage follower module as described in this embodiment of the application.

[0036] In this embodiment of the application, a vehicle employs a water pump drive circuit for an automotive thermal management controller as described in this embodiment of the application.

[0037] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A voltage follower module for use in a thermal management controller water pump drive circuit, characterized in that, Includes operational amplifier U1A, operational amplifier U1B, resistors R1 to R6, and capacitors C1 to C3; The non-inverting input of operational amplifier U1A is connected to voltage P5V_Nor via resistor R3, and is also grounded via resistor R5. The inverting input of operational amplifier U1A is connected to voltage P5V_Up via resistor R4, and is also connected to the output of operational amplifier U1A via resistor R6. The positive power supply of operational amplifier U1A is connected to voltage P5V_Up, and is also grounded via capacitor C1. The negative power supply of operational amplifier U1A is grounded. The output of operational amplifier U1A is also connected to voltage P5V_Up via resistors R2 and R1. The non-inverting input terminal of the operational amplifier U1B is connected to the junction of resistors R2 and R1, and the inverting input terminal of the operational amplifier U1B is connected to the output terminal of the operational amplifier U1B, forming a voltage follower structure; the output terminal of the operational amplifier U1B is grounded through capacitor C3, and the output terminal of the operational amplifier U1B is also connected to voltage P2V5_VREF. The capacitor C2 is connected in parallel with the resistor R2.

2. The voltage follower module according to claim 1, characterized in that, The resistance values ​​of resistors R3, R4, R5, and R6 are equal.

3. The voltage follower module according to claim 2, characterized in that, The resistance values ​​of resistors R1 and R2 are equal.

4. The voltage follower module according to claim 3, characterized in that, The output voltage of the operational amplifier U1A is P5V_Nor - P5V_Up; the output voltage of the operational amplifier U1B is: 1 / 2[P5V_Up - (P5V_Nor - P5V_Up)] = 1 / 2(P5V_Up).

5. A thermal management controller water pump drive circuit, characterized in that, The voltage follower module as described in claim 1 or 2 is used.

6. A vehicle, characterized in that: The water pump drive circuit of the automotive thermal management controller as described in claim 3 is adopted.

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