A motor temperature detection circuit

Abstract

The application discloses a motor temperature detection circuit, which is characterized in that the detection circuit comprises a constant current source circuit, a micro control unit and a sensor input unit; the constant current source circuit comprises a first voltage dividing resistor, a second voltage dividing resistor and a voltage stabilizing tube, wherein the voltage stabilizing tube outputs a first voltage, and the first voltage dividing resistor and the second voltage dividing resistor output a second voltage; the micro control unit receives the first voltage and the second voltage, and is used for eliminating errors caused by the first voltage and the second voltage in combination with a preset error elimination algorithm; and the first voltage and the second voltage after the errors are eliminated are used for detecting the motor temperature of a motor temperature sensor. It can be seen that, in the technical scheme of the application, the micro control unit receives the voltages from the voltage dividing resistors and the voltage stabilizing tube in the constant current source circuit, so as to eliminate errors caused by temperature drift of the corresponding voltages of the voltage dividing resistors and the voltage stabilizing tube in the constant current source circuit in combination with the preset error elimination algorithm, thereby making the currents on the whole circuit equal, and further improving the detection precision of the motor temperature.

Description

Technical Field

[0001] This application relates to the field of motor technology, and in particular to a motor temperature detection circuit. Background Technology

[0002] With the gradual development of electric vehicles, they have attracted widespread attention and are being used extensively by users, gradually becoming a direction for future sustainable development. However, it is also important to note that electric vehicle motors generate heat during operation. If this heat is not detected and addressed with timely cooling and temperature control, it can lead to motor damage.

[0003] Currently, motor temperature sampling circuits have been proposed in related technologies to detect motor temperature. However, traditional motor temperature sampling circuits are mostly suitable for scenarios where the motor temperature and resistance change little. If the external temperature is high, the motor temperature and resistance will often change greatly, which can easily cause temperature drift of the circuit components in the sampling circuit, and also lead to a large error in the detected motor temperature.

[0004] Therefore, improving the accuracy of motor temperature detection is a key issue of concern to those skilled in the art. Summary of the Invention

[0005] To address the aforementioned problems, this application provides a motor temperature detection circuit, aiming to improve the accuracy of motor temperature detection. The embodiments of this application disclose the following technical solutions:

[0006] To address the aforementioned technical problems, this application discloses a motor temperature detection circuit, which includes a constant current source circuit, a microcontroller unit, and a sensor input unit.

[0007] The constant current source circuit includes a first voltage divider resistor, a second voltage divider resistor, and a Zener diode, wherein the Zener diode outputs a first voltage, and a second voltage is output between the first voltage divider resistor and the second voltage divider resistor, and the first voltage divider resistor and the second voltage divider resistor are two voltage divider resistors of the same specification.

[0008] The microcontroller receives the first voltage and the second voltage, and uses a preset error elimination algorithm to eliminate the error caused by the first voltage and the second voltage.

[0009] The motor temperature of the motor in the sensor input unit is detected using the first and second voltages after error elimination.

[0010] Optionally, the preset error elimination algorithm is specifically as follows:

[0011] Step 1: Calculate the virtual currents of the first voltage divider and the second voltage divider;

[0012] Step 2: Combine the virtual current with the preset error elimination formula to calculate the actual current of the first voltage divider and the second voltage divider;

[0013] Step 3: After eliminating the error using the preset error elimination formula, obtain the actual current of the first voltage divider and the second voltage divider.

[0014] Optionally, the constant current source circuit may further include a first filter capacitor, a third voltage divider resistor, a transistor, a pull-up resistor, and a power supply voltage.

[0015] Optionally, the first voltage divider resistor is connected in series with the second voltage divider resistor, the third voltage divider resistor, and the transistor; the first filter capacitor is connected in parallel with the first voltage divider resistor, the second voltage divider resistor, and the Zener diode; the pull-up resistor and the Zener diode are connected in series with the supply voltage; and one end of the transistor is connected between the pull-up resistor and the Zener diode.

[0016] Optionally, the detection circuit further includes a second filter capacitor and a fourth voltage divider resistor, wherein the sensor input unit is connected in parallel with the fourth voltage divider resistor and the second filter capacitor, the second filter capacitor is connected in series with the constant current source circuit, and the constant current source circuit is connected in parallel with the microcontroller unit.

[0017] Optionally, the detection circuit further includes a line resistor, a signal isolation circuit, a temperature differential amplifier circuit, and a low-pass filter circuit, wherein the line resistor is connected in series with the signal isolation circuit, the temperature differential amplifier circuit, and the low-pass filter circuit, and the low-pass filter circuit is connected in series with the microcontroller unit.

[0018] Optionally, the signal isolation circuit includes a first operational amplifier, the negative terminal of which is connected to the temperature differential amplifier circuit, and the signal isolation circuit is used to isolate part of the current from the constant current source circuit.

[0019] Optionally, the temperature differential amplifier circuit includes a second operational amplifier, the negative terminal of which is connected to the low-pass filter circuit. The temperature differential amplifier circuit is used to amplify the actual voltage of the motor sensor to obtain an amplified voltage, so that the microcontroller unit can obtain the actual resistance of the motor temperature sensor by combining the amplified voltage.

[0020] Optionally, the temperature difference amplifier circuit amplifies the actual voltage using a preset amplification voltage formula to obtain the amplified voltage.

[0021] Optionally, the low-pass filter circuit is used to filter the amplified voltage.

[0022] Compared with the prior art, this application has the following beneficial effects:

[0023] The detection circuit disclosed in this application includes a constant current source circuit, a microcontroller unit, and a sensor input unit. The constant current source circuit includes a first voltage divider resistor, a second voltage divider resistor, and a Zener diode. The Zener diode outputs a first voltage, and a second voltage is output between the first and second voltage divider resistors. The first and second voltage divider resistors are two voltage divider resistors of the same specification. At this stage, the microcontroller unit receives the first and second voltages and uses a preset error elimination algorithm to eliminate the error caused by the first and second voltages. The error-eliminated first and second voltages are then used to detect the motor temperature from the motor temperature sensor in the sensor input unit. Therefore, in this technical solution, the microcontroller unit receives the voltages from the voltage divider resistors and the Zener diode in the constant current source circuit, and uses the preset error elimination algorithm to eliminate the error caused by temperature drift in the corresponding voltages of the voltage divider resistors and the Zener diode, thereby ensuring equal current throughout the circuit and improving the detection accuracy of the motor temperature. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 A circuit schematic diagram of a motor temperature detection circuit provided in an embodiment of this application;

[0026] Figure 2 The output voltage pattern of the motor temperature detection circuit provided in the embodiment of this application. Detailed Implementation

[0027] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of this application.

[0028] It should be noted that the motor temperature detection circuit provided in this application is for the field of motor technology. The above is only an example and does not limit the application field of the method and device provided in this application.

[0029] As described earlier, with the gradual development of electric vehicles, they have attracted widespread attention and are being used extensively by users, gradually becoming a direction for future sustainable development. However, it is also important to note that electric vehicle motors generate heat during operation. If this heat is not detected and cooled and controlled in a timely manner, it can cause damage to the motor. Currently, motor temperature sampling circuits are proposed in related technologies to detect motor temperature. However, traditional motor temperature sampling circuits are mostly suitable for scenarios where the motor temperature and resistance changes are small. In high-temperature environments, the motor temperature and resistance often change significantly, easily causing temperature drift in the circuit components and resulting in large errors in the detected motor temperature. Therefore, how to improve the accuracy of motor temperature detection is a key issue of concern for those skilled in the art.

[0030] Therefore, the inventors have proposed the technical solution of this application. The detection circuit disclosed in this application includes a constant current source circuit, a microcontroller unit, and a sensor input unit. The constant current source circuit includes a first voltage divider resistor, a second voltage divider resistor, and a Zener diode. The Zener diode outputs a first voltage, and a second voltage is output between the first and second voltage divider resistors. The first and second voltage divider resistors are two voltage divider resistors of the same specification. At this stage, the microcontroller unit receives the first and second voltages and uses a preset error elimination algorithm to eliminate the error caused by the first and second voltages. The first and second voltages after error elimination are then used to detect the motor temperature from the motor temperature sensor in the sensor input unit. It can be seen that in the technical solution of this application, the microcontroller unit receives the voltages from the voltage divider resistors and the Zener diode in the constant current source circuit, and uses the preset error elimination algorithm to eliminate the error caused by temperature drift in the corresponding voltages of the voltage divider resistors and the Zener diode in the constant current source circuit. This ensures that the current in the entire circuit is equal, thereby improving the detection accuracy of the motor temperature.

[0031] To enable those skilled in the art to better understand the present application, the present application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0032] The following embodiment illustrates a motor temperature detection circuit provided in this application.

[0033] See Figure 1 The figure shown is a circuit diagram of a motor temperature detection circuit provided in an embodiment of this application. Figure 1 As shown, the detection circuit may include a constant current source circuit, a microcontroller unit (MCU), and a sensor input unit. The sensor input unit consists of a resistive motor temperature sensor (RX). The motor temperature sensor can be of various models such as NTC, PT100, or PT1000; no specific limitation is made here, and the appropriate sensor can be selected based on actual needs in practical applications.

[0034] Since traditional motor temperature sampling circuits in related technologies are mostly suitable for scenarios where the motor temperature and resistance changes are small, this application proposes to use a microcontroller unit with a preset error elimination algorithm to eliminate the error caused by temperature drift of the Zener diode and voltage divider resistor.

[0035] Specifically, the constant current source circuit in this application includes a first voltage divider resistor R1, a second voltage divider resistor R2, and a Zener diode U1. Figure 2 The output voltage pattern of the motor temperature detection circuit provided in this embodiment of the application is shown. Figure 2 As shown, the Zener diode outputs the first voltage V. R1 The second voltage V is output between the first voltage divider resistor R1 and the second voltage divider resistor R2. R2 The first voltage divider resistor R1 and the second voltage divider resistor R2 are two voltage divider resistors of the same specification. It is understood that the temperature drift of the Zener diode due to high-temperature environmental factors is much higher than that of the voltage divider resistor. Therefore, this application proposes to use two or more voltage divider resistors to balance the error.

[0036] Then, the microcontroller receives the first voltage V. R1 Second voltage V R2 Used to eliminate the first voltage V by combining with a preset error elimination algorithm. R1 Second voltage V R2 The resulting error. Specifically, the preset error elimination algorithm is as follows:

[0037] Step 1: Calculate the first voltage V using the virtual current calculation formula. R1 Second voltage V R2 The virtual current.

[0038] Understandably, when the constant current source circuit is working, transistor Q1 is turned on, and Zener diode U1 outputs the first voltage V. R1 The second voltage V is output between the first voltage divider resistor R1 and the second voltage divider resistor R2. R2 Therefore, the virtual current flowing through the first voltage divider resistor R1 and the second voltage divider resistor R2 is:

[0039]

[0040] Step 2: Combine the virtual current with the preset error elimination formula to calculate the actual current of the first and second voltage dividers.

[0041] Due to environmental factors such as temperature, the resistance values ​​output by the Zener diode U1, the first voltage divider resistor R1, and the second voltage divider resistor R2 are not accurate. If the virtual current calculated based on these resistance values ​​is used for further calculations, it will lead to a deviation in the output of the constant current source circuit. Therefore, the virtual current is combined with a preset error elimination formula to calculate the first voltage V. R1Second voltage V R2 The actual current.

[0042] The preset error elimination formula is:

[0043] ΔR is the error value.

[0044] The virtual current combined with the preset error elimination formula is as follows:

[0045]

[0046] Step 3: After eliminating the error using the preset error elimination formula, obtain the actual current of the first and second voltage dividers.

[0047] After considering the error value, the first voltage V is obtained. R1 Second voltage V R2 The actual current is:

[0048]

[0049] Finally, the motor temperature is detected by the motor temperature sensor in the sensor input unit using the first and second voltages after error elimination. Thus, by using identical dual voltage divider resistors and Zener diodes to form a constant current source circuit, and by eliminating errors caused by temperature drift of the Zener diodes and voltage divider resistors through a preset error elimination algorithm, the detection accuracy of the motor temperature is improved.

[0050] Furthermore, the constant current source circuit also includes a first filter capacitor C2, a third voltage divider resistor R3, a transistor Q1, a pull-up resistor R4, and a supply voltage VCC. Specifically, the first voltage divider resistor R1 is connected in series with the second voltage divider resistor R2, the third voltage divider resistor R3, and the transistor Q1; the first filter capacitor C1 is connected in parallel with the first voltage divider resistor R1, the second voltage divider resistor R2, and the Zener diode U1; the pull-up resistor R4 and the Zener diode U1 are connected in series with the supply voltage VCC; and one end of the transistor Q1 is connected between the pull-up resistor R4 and the Zener diode U1.

[0051] In one feasible implementation, the detection circuit further includes a second filter capacitor C2, a fourth voltage divider resistor R5, and a supply voltage VCC. The sensor input unit is connected in parallel with the fourth voltage divider resistor R5 and the second filter capacitor C2. The second filter capacitor C2 is connected in series with the constant current source circuit and the supply voltage VCC. The constant current source circuit is then connected in parallel with the microcontroller unit. It is understood that the motor temperature sensor RX in the sensor input unit is connected in parallel with the fourth voltage divider resistor R5 and the second filter capacitor C2.

[0052] In another feasible implementation, the detection circuit further includes a line resistor R6, a signal isolation circuit, a temperature differential amplifier circuit, and a low-pass filter circuit, wherein the line resistor R6 is connected in series with the signal isolation circuit, the temperature differential amplifier circuit, and the low-pass filter circuit, and the low-pass filter circuit is connected in series with the microcontroller unit.

[0053] Specifically, the signal isolation circuit includes a first operational amplifier U1A and a fifth voltage divider resistor R7. The positive terminal of the first operational amplifier U1A is connected to the fifth voltage divider resistor R7, and the negative terminal of the first operational amplifier U1A is connected to the temperature differential amplifier circuit. The signal isolation circuit is used to isolate part of the current from the constant current source circuit. It can be understood that the signal isolation circuit is used to filter out the current with a large error that still exists after the error has been eliminated by the microcontroller unit, to prevent the current with a large error in the constant current source circuit from affecting the subsequent temperature differential amplifier circuit.

[0054] The temperature differential amplifier circuit includes a second operational amplifier U2A, a third filter capacitor C3, a fourth filter capacitor C4, a sixth voltage divider resistor R8, a seventh voltage divider resistor R9, and an eighth voltage divider resistor R10. The positive terminal of the second operational amplifier U2A is connected to the line resistor R6 via the third filter capacitor C3 and the sixth voltage divider resistor R8. The third filter capacitor C3 and the sixth voltage divider resistor R8 are connected in parallel, and the sixth voltage divider resistor R8 is grounded. The negative terminal of the second operational amplifier is connected to a low-pass filter circuit. The fourth filter capacitor C4 and the eighth voltage divider resistor R10 are connected in series, and the fourth filter capacitor C4 and the seventh voltage divider resistor R9 are connected in parallel. The temperature differential amplifier circuit amplifies the actual voltage of the motor temperature sensor RX to obtain an amplified voltage, which the microcontroller unit uses to obtain the actual resistance of the motor temperature sensor.

[0055] Furthermore, the temperature differential amplifier circuit amplifies the actual voltage using a preset amplification voltage formula, resulting in the following amplified voltage:

[0056] After the microcontroller unit uses a preset error elimination algorithm to eliminate the error caused by temperature drift of the Zener diode and voltage divider resistor, the actual current and actual voltage flowing through the motor temperature sensor RX are calculated.

[0057] The formula for calculating the actual current is as follows:

[0058]

[0059] The formula for calculating the actual voltage is as follows:

[0060]

[0061] At this stage, the voltage V of the motor temperature sensor RX RXThe signal flows through the signal isolation circuit to the temperature differential amplifier circuit. At this point, the temperature differential amplifier circuit, based on a preset amplification voltage formula, measures the actual voltage V of the motor temperature sensor RX. RX After amplification by N times, the amplified voltage V_ is obtained. TMP .

[0062] The preset amplification voltage formula is as follows:

[0063]

[0064] The low-pass filter circuit includes a fifth filter capacitor C5 and a ninth voltage divider resistor R11. The fifth filter capacitor C5 is grounded, and the fifth filter capacitor C5 and the ninth voltage divider resistor R11 are connected in series. The low-pass filter circuit is used to filter the amplified voltage. It can be understood that the low-pass filter circuit filters the amplified voltage V_ TMP Perform filtering. For example... Figure 2 As shown, the low-pass filter circuit will filter the amplified voltage V_ TMP The data is input into the microcontroller unit. This allows the microcontroller unit to obtain the actual resistance value of the motor sensor, and then use this actual resistance value to determine the corresponding temperature of the motor sensor, thus improving the accuracy of motor temperature detection.

[0065] The actual resistance value of the motor sensor can be obtained using the following formula:

[0066]

[0067] As can be seen, in this optional scheme, the detection circuit includes a constant current source circuit, a microcontroller unit, and a sensor input unit; the constant current source circuit includes a first voltage divider resistor, a second voltage divider resistor, and a Zener diode, wherein the Zener diode outputs a first voltage, and a second voltage is output between the first and second voltage divider resistors, and the first and second voltage divider resistors are two voltage divider resistors of the same specification; the microcontroller unit receives the first voltage and the second voltage, and uses them to eliminate the error caused by the first voltage and the second voltage in combination with a preset error elimination algorithm; the motor temperature of the motor temperature sensor in the sensor input unit is detected using the first voltage and the second voltage after the error is eliminated.

[0068] In summary, this embodiment utilizes a microcontroller unit to receive the voltage from the voltage divider resistor and Zener diode in the constant current source circuit. This, combined with a preset error elimination algorithm, eliminates the error caused by temperature drift in the corresponding voltages of the voltage divider resistor and Zener diode in the constant current source circuit, thereby ensuring that the current in the entire circuit is equal and thus improving the accuracy of motor temperature detection.

[0069] It should be noted that the "first" and "second" in the names such as "first" and "second" (if they exist) mentioned in the embodiments of this application are only used as name identifiers and do not represent the first and second in order.

[0070] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0071] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0072] The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein can be implemented directly by hardware, a software module executed by a processor, or a combination of both. The software module can be located in random access memory (RAM), main memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art.

[0073] The above provides a detailed description of a motor temperature detection circuit provided in this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the embodiments above are merely for the purpose of helping to understand the method and core ideas of this application. It should be noted that those skilled in the art can make various improvements and modifications to this application without departing from its principles, and these improvements and modifications also fall within the protection scope of the claims of this application.

Claims

1. A motor temperature detection circuit, characterized in that, The detection circuit includes a constant current source circuit, a microcontroller unit, and a sensor input unit; The constant current source circuit includes a first voltage divider resistor, a second voltage divider resistor, and a Zener diode, wherein the Zener diode outputs a first voltage, and a second voltage is output between the first voltage divider resistor and the second voltage divider resistor, and the first voltage divider resistor and the second voltage divider resistor are two voltage divider resistors of the same specification. The microcontroller receives the first voltage and the second voltage, and uses a preset error elimination algorithm to eliminate the error caused by the first voltage and the second voltage. The motor temperature of the motor sensor in the sensor input unit is detected using the first voltage and the second voltage after error elimination. The preset error elimination algorithm is specifically as follows: Step 1: Calculate the virtual currents of the first voltage divider and the second voltage divider; Step 2: Combine the virtual current with the preset error elimination formula to calculate the actual current of the first voltage divider and the second voltage divider, wherein the virtual current... Combined with the preset error elimination formula Specifically: ; Step 3: After eliminating the error using the preset error elimination formula, the actual currents of the first voltage divider and the second voltage divider are obtained as follows: ,in Indicates the first partial pressure. This indicates the second pressure component.

2. The detection circuit according to claim 1, characterized in that, The constant current source circuit also includes a first filter capacitor, a third voltage divider resistor, a transistor, a pull-up resistor, and a power supply voltage.

3. The detection circuit according to claim 2, characterized in that, The first voltage divider resistor is connected in series with the second voltage divider resistor, the third voltage divider resistor, and the transistor; the first filter capacitor is connected in parallel with the first voltage divider resistor, the second voltage divider resistor, and the Zener diode; the pull-up resistor and the Zener diode are connected in series with the supply voltage; and one end of the transistor is connected between the pull-up resistor and the Zener diode.

4. The detection circuit according to claim 1, characterized in that, The detection circuit further includes a second filter capacitor and a fourth voltage divider resistor, wherein the sensor input unit is connected in parallel with the fourth voltage divider resistor and the second filter capacitor, the second filter capacitor is connected in series with the constant current source circuit, and the constant current source circuit is connected in parallel with the microcontroller unit.

5. The detection circuit according to claim 1, characterized in that, The detection circuit further includes a line resistor, a signal isolation circuit, a temperature differential amplifier circuit, and a low-pass filter circuit, wherein the line resistor is connected in series with the signal isolation circuit, the temperature differential amplifier circuit, and the low-pass filter circuit, and the low-pass filter circuit is connected in series with the microcontroller unit.

6. The detection circuit according to claim 5, characterized in that, The signal isolation circuit includes a first operational amplifier, the negative terminal of which is connected to the temperature differential amplifier circuit. The signal isolation circuit is used to isolate a portion of the current from the constant current source circuit.

7. The detection circuit according to claim 5, characterized in that, The temperature differential amplifier circuit includes a second operational amplifier, the negative terminal of which is connected to the low-pass filter circuit. The temperature differential amplifier circuit is used to amplify the actual voltage of the motor temperature sensor to obtain an amplified voltage, so that the microcontroller unit can obtain the actual resistance of the motor temperature sensor by combining the amplified voltage.

8. The detection circuit according to claim 7, characterized in that, The temperature difference amplifier circuit amplifies the actual voltage using a preset amplification voltage formula to obtain the amplified voltage.

9. The detection circuit according to claim 7, characterized in that, The low-pass filter circuit is used to filter the amplified voltage.

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