Temperature detection circuit, temperature monitoring method and electric vehicle

Abstract

The present application relates to a temperature detection circuit, a temperature monitoring method and an electric vehicle, wherein the circuit comprises: a temperature sensor, a constant current module and a processing module; the constant current module is connected to the temperature sensor and is used to provide a constant current to the temperature sensor; the processing module is connected to the temperature sensor and is used to obtain a temperature sampling signal of the temperature sensor and perform a first processing on the temperature sampling signal to obtain a corresponding oil pump temperature; wherein the temperature sampling signal is determined by the resistance value and the constant current of the temperature sensor. Through the present application, the influence of various interferences such as electromagnetic interference on the temperature measurement accuracy can be overcome, data distortion can be reduced, and the temperature monitoring data can be made more accurate.

Description

Technical Field

[0001] The present application relates to the field of electronic circuits, and in particular to a temperature detection circuit, a temperature monitoring method and an electric vehicle. Background Art

[0002] The electric hydraulic steering system in electric vehicles is a steering solution that uses an electric motor instead of the engine as the power source for the steering oil pump. The oil pump motor is one of the most core components in the electric hydraulic steering system. The system must work regardless of whether it is steering or not, and large steering at low speed requires the oil pump motor to output more power to obtain relatively large assist. Frequently exceeding the rated current or overloading will cause the oil pump motor and oil temperature to rise. The temperature rise of the oil pump oil temperature determines the service life of the motor. Therefore, in the electric hydraulic steering system, the oil pump motor driver needs to detect and monitor the oil pump oil temperature to ensure the normal operation of the oil pump motor and control system.

[0003] The temperature of the oil pump motor is usually measured by the buried thermometer method, that is, a temperature sensor is placed in the oil pump motor. The oil temperature measurement is based on the same principle as the oil pump motor temperature measurement. The temperature sensor has high precision, vibration resistance, good stability, and a wide range of applications. Therefore, oil and air pumps generally use temperature sensors. In the existing temperature sampling technology, a constant voltage source detection method is generally used to connect the temperature sensor to a fixed resistance resistor. Using the principle of resistor voltage division, the temperature change causes the pressure difference between the two ends of the temperature sensor to change, thereby detecting the temperature. Although this detection method can detect the temperature change trend, due to the physical characteristics of the temperature sensor, its resistance value changes little with temperature, resulting in a small pressure difference, which makes the detection temperature very inaccurate, low in precision, and seriously distorted in monitoring data, and thus cannot ensure the normal operation of the oil pump motor. The reliability is poor and it is not suitable for use occasions with a wide temperature matching range and high sampling accuracy. In addition, the oil pump oil temperature detection transmission cable is very long. When there is a strong electromagnetic field near the temperature sampling and power supply cables, the electromagnetic interference caused will seriously affect the measurement accuracy. Summary of the invention

[0004] In order to solve the above-mentioned technical problems that the monitored temperature data is distorted due to low accuracy and the electromagnetic interference seriously affects the measurement accuracy, the embodiments of the present application provide a temperature detection circuit, a temperature monitoring method and an electric vehicle.

[0005] In a first aspect, an embodiment of the present application provides a temperature detection circuit, the circuit comprising: a temperature sensor, a constant current module, and a processing module;

[0006] The constant current module is connected to the temperature sensor to provide a constant current to the temperature sensor;

[0007] The processing module is connected to the temperature sensor, and is used to obtain a temperature sampling signal from the temperature sensor, and perform a first processing on the temperature sampling signal to obtain a corresponding oil pump temperature;

[0008] The temperature sampling signal is determined by the resistance value and constant current of the temperature sensor.

[0009] Optionally, the circuit between the temperature sensor and the processing module further includes an amplification module;

[0010] The amplification module is used for performing a second process on the temperature sampling signal to obtain a second processed temperature sampling signal;

[0011] The processing module is specifically used to obtain the temperature sampling signal after the second processing, and perform the first processing on the temperature sampling signal after the second processing to obtain the corresponding oil pump temperature.

[0012] Optionally, the constant current module includes: a first power supply, a constant voltage source module, a first operational amplifier, a first resistor, a triode, a second resistor, and a third resistor;

[0013] The output end of the constant voltage source module is connected to the non-inverting input end of the first operational amplifier, the inverting input end of the first operational amplifier is grounded through a first resistor, the base of the transistor is connected to the output end of the first operational amplifier through a second resistor, the collector of the transistor is connected to the first power supply through a third resistor, and the emitter of the transistor is grounded through a temperature sensor and a first resistor in sequence.

[0014] Optionally, the constant current module further includes: a first filtering module;

[0015] The first side of the first filter module is connected between the emitter of the transistor and the first end of the temperature sensor, and the second side of the first filter module is connected between the inverting input end of the first operational amplifier and the second end of the temperature sensor.

[0016] Optionally, the constant current module further includes: a second filtering module and a third filtering module;

[0017] The second filter module is connected in parallel with the first resistor;

[0018] One end of the third filter module is connected to the emitter of the transistor, and the other end is connected to the inverting input end of the first operational amplifier.

[0019] Optionally, the amplification module includes: a first sub-amplification module, a first isolation module, and a second sub-amplification module;

[0020] The input end of the first sub-amplifier module is respectively connected to the emitter of the triode and the inverting input end of the first operational amplifier, and the output end of the first sub-amplifier module is connected to the input end of the first isolation module;

[0021] The output end of the first isolation module is connected to the input end of the second sub-amplification module;

[0022] The output end of the second sub-amplifier module is connected to the processing module.

[0023] Optionally, the first sub-amplification module includes: a second operational amplifier, a fourth resistor, a fifth resistor, a sixth resistor, and a seventh resistor. The emitter of the transistor is connected to the non-inverting input terminal of the second operational amplifier through the fourth resistor, the inverting input terminal of the first operational amplifier is connected to the inverting input terminal of the second operational amplifier through the fifth resistor, the non-inverting input terminal of the second operational amplifier is also grounded through the sixth resistor, the inverting input terminal of the second operational amplifier is also connected to the output terminal of the second operational amplifier through the seventh resistor, and the output terminal of the second operational amplifier is connected to the input terminal of the first isolation module.

[0024] Optionally, the first sub-amplification module further includes: a second isolation module;

[0025] The input end of the second isolation module is respectively connected to the emitter of the transistor and the inverting input end of the first operational amplifier, and the output end of the second isolation module is respectively connected to the non-inverting input end and the inverting input end of the second operational amplifier through the fourth resistor and the fifth resistor.

[0026] Optionally, the first isolation module includes an isolation optical coupler, and the second sub-amplification module includes a third operational amplifier, an eighth resistor, and a ninth resistor;

[0027] The input end of the isolation optocoupler is connected to the output end of the second operational amplifier, the positive output end of the isolation optocoupler is connected to the in-phase input end of the third operational amplifier through the eighth resistor, the negative output end of the isolation optocoupler is connected to the inverting input end of the third operational amplifier through the ninth resistor, and the output end of the third operational amplifier is connected to the processing module.

[0028] Optionally, the processing module is further used to control the operation of the oil pump according to the temperature of the oil pump.

[0029] In a second aspect, an embodiment of the present application provides a temperature monitoring method, the method comprising:

[0030] Acquiring the oil pump temperature according to any of the temperature detection circuits described above;

[0031] Comparing the oil pump temperature with a preset threshold value to obtain a comparison result;

[0032] Obtaining a corresponding control strategy according to the comparison result;

[0033] The temperature of the oil pump is controlled according to the control strategy.

[0034] In a third aspect, an embodiment of the present application provides an electric vehicle, which includes the temperature detection circuit described in any of the above items.

[0035] Optionally, the electric vehicle controls the temperature of the oil pump according to the temperature monitoring method described above.

[0036] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0037] The temperature detection circuit provided by the embodiment of the present application includes: a temperature sensor, a constant current module, and a processing module; the constant current module is connected to the temperature sensor and is used to provide a constant current to the temperature sensor; the processing module is connected to the temperature sensor and is used to obtain the temperature sampling signal of the temperature sensor, and the temperature sampling signal is first processed to obtain the corresponding oil pump temperature; wherein the temperature sampling signal is determined by the resistance value and the constant current of the temperature sensor. The present application provides a constant current to the temperature sensor so that the temperature sampling signal of the temperature sensor is only related to the resistance value of the temperature sensor that changes with the temperature, thereby reducing or eliminating the interference of electromagnetic interference on temperature detection and improving the temperature measurement accuracy; in addition, by amplifying the temperature sampling signal through amplification processing, any temperature change can be captured, which is suitable for a wide range of temperature detection, reduces the distortion of monitoring data, and is highly accurate. The technical solution of the present application can be applied to the oil pump temperature detection of electric vehicles. The present application improves the accuracy of oil pump temperature detection and the anti-electromagnetic interference capability during temperature detection, effectively improves the reliability of the oil pump temperature detection system, and ensures the reliable operation of electric vehicles. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0039] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0040] Figure 1 A structural block diagram of a temperature detection circuit provided by an embodiment;

[0041] Figure 2 A structural block diagram of a temperature detection circuit provided by another embodiment;

[0042] Figure 3 is a circuit diagram of a temperature detection circuit in one embodiment;

[0043] Figure 4 FIG. 4 is a flow chart of a temperature monitoring method in an embodiment. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0045] Figure 1 A structural block diagram of a temperature detection circuit provided by an embodiment. Figure 1 , the temperature detection circuit includes a constant current module 100, a temperature sensor 300, and a processing module 500. The constant current module 100 is electrically connected to the temperature sensor 300, and the temperature sensor 300 is electrically connected to the processing module 500. The temperature sensor 300 is placed in the oil pump motor to measure the oil temperature of the oil pump or the temperature of the oil pump motor. The constant current module 100 is used to provide a constant current to the temperature sensor 300, that is, as a constant current source for the temperature sensor 300. Because the current flowing through the temperature sensor 300 is constant, and the resistance of the temperature sensor 300 changes with temperature, the voltage across the temperature sensor 300 will change with temperature. The voltage across the temperature sensor 300 is a temperature sampling signal. Therefore, the temperature sampling signal is determined by the constant current flowing through the temperature sensor 300 and the resistance of the temperature sensor 300 itself. Since the constant current is a fixed value, the actual voltage change of the temperature sensor 300 changes with the change of its own resistance, and its own resistance changes with the change of the temperature at its location. Therefore, the actual voltage of the temperature sensor 300 is linearly related to the oil pump temperature.

[0046] The temperature sensor 300 may be a PT100 temperature sensor, which has high accuracy, vibration resistance, good stability and a wide range of applications.

[0047] The processing module 500 is used to obtain the voltage across the temperature sensor 300, that is, to obtain the temperature sampling signal, and to perform a first process on the temperature sampling signal to obtain the oil pump temperature. The processing module 500 may include a DSP (Digital Signal Processing) digital signal processing module, which is used to perform digital processing on the temperature sampling signal to obtain the oil pump temperature. The voltage across the temperature sensor 300 is linearly related to the oil pump temperature.

[0048] Figure 1The temperature detection circuit shown provides a constant current to the temperature sensor 300 through the constant current module 100, so that the voltage across the temperature sensor 300 is only related to the change in the resistance value of the temperature sensor 300. Even if there is a strong electromagnetic field near the temperature sampling and power supply cables, the impact on the temperature sensor 300 is small. The influence of electromagnetic interference on the voltage signal across the temperature sensor 300 is reduced or eliminated, so that the temperature sampling signal truly reflects the oil pump temperature, and then obtains accurate temperature measurement data. Since the current is constant, the temperature sampling signal is linearly related to the temperature and has high accuracy.

[0049] Figure 2 A structural block diagram of a temperature detection circuit provided in another embodiment. Figure 1 Based on the temperature detection circuit, the temperature detection circuit further includes an amplification module 400. One end of the amplification module 400 is electrically connected to the temperature sensor 300, and the other end is electrically connected to the processing module 500. The amplification module 400 is used to perform a second process on the temperature sampling signal to obtain a temperature sampling signal after the second process.

[0050] The second processing is specifically an amplification processing. Because the resistance of the temperature sensor 300 changes little with temperature, the temperature sampling signal is small, so the detection temperature accuracy is low and the temperature monitoring data is seriously distorted. The temperature sampling signal can be amplified by the amplification processing. Even if the temperature change is small, the temperature change can be captured based on the temperature sampling signal with a small change. The amplification processing can also reduce the distortion caused by the signal attenuation caused by signal transmission to the restoration of the measured temperature, so that the final oil pump temperature signal is not only highly accurate, but also can restore the temperature corresponding to any temperature sampling signal.

[0051] Figure 3 FIG. 1 is a circuit diagram of a temperature detection circuit in an embodiment. Figure 3 The constant current module 100 includes: a first power supply V1, a constant voltage source module 110, a first operational amplifier: an operational amplifier 1, a first resistor R6, a transistor, a second resistor R4, and a third resistor R5.

[0052] The output end of the constant voltage source module 110 is connected to the non-inverting input end of the operational amplifier 1, the inverting input end of the operational amplifier 1 is grounded through the first resistor R6, the base of the transistor is connected to the output end of the operational amplifier 1 through the second resistor R4, the collector of the transistor is connected to the first power supply V1 through the third resistor R5, and the emitter of the transistor is grounded through the temperature sensor PT100 and the first resistor R6 in sequence.

[0053] The first power supply V1, resistor R5, transistor, temperature sensor PT100, resistor R6 and ground are electrically connected in sequence to form a closed loop. The constant voltage source module 110, operational amplifier 1 and resistor R4 are electrically connected in sequence to provide a conduction voltage for the base of the transistor.

[0054] In a specific embodiment, the constant voltage source module 110 includes a three-terminal voltage regulator, capacitors C1, C2, resistors R1, R2, and R3. The first power supply V1 is connected to the input terminal of the three-terminal voltage regulator, one end of the capacitor C1, and one end of the capacitor C2 through the resistor R1; the ground terminal of the three-terminal voltage regulator, the other end of the capacitor C1, and the other end of the capacitor C2 are all grounded; the output terminal of the three-terminal voltage regulator is grounded through the resistor R2 and the resistor R3 in turn; the common node of the resistor R2 and the resistor R3 is connected to the in-phase input terminal of the operational amplifier 1.

[0055] The three-terminal voltage regulator may be a three-terminal adjustable voltage regulator.

[0056] The output end of the three-terminal regulator outputs a stable reference voltage, and the reference voltage is divided by resistors R2 and R3 to obtain a fixed voltage, which is the voltage across resistor R3. It can be seen from the characteristics of the operational amplifier that the voltages of the in-phase input and inverting input of operational amplifier 1 are always equal here. Because the resistance values ​​of resistors R2 and R3 remain unchanged, the voltage divided across resistor R3 remains unchanged, and thus the voltage of the inverting input of operational amplifier 1 remains unchanged. One end of resistor R6 is connected to the inverting input of operational amplifier 1 and the other end is grounded, so the voltage across resistor R6 remains unchanged. The voltage across resistor R6 remains unchanged, and the resistance value of resistor R6 remains unchanged, so the current flowing through resistor R6 is constant; the temperature sensor PT100 is connected in series with resistor R6, so the current flowing through temperature sensor PT100 is constant.

[0057] The transistor is used to make the current output by the operational amplifier 1 meet the output current requirement of the temperature sensor PT100, that is, to make the current flowing through the temperature sensor PT100 not exceed the maximum current that the temperature sensor PT100 can withstand.

[0058] In a specific embodiment, referring to Figure 3 The constant current module 100 also includes: a first filtering module 120 .

[0059] The first side of the first filter module 120 is connected between the emitter of the transistor and the first end of the temperature sensor PT100 , and the second side of the first filter module 120 is connected between the inverting input end of the operational amplifier 1 and the second end of the temperature sensor PT100 .

[0060] Specifically, the first filter module 120 includes a first sub-filter module and a second sub-filter module. The first sub-filter module includes capacitors C11, C12, C14, C15 and inductors L1 and L2, and the second sub-filter module includes capacitor C13 and inductor L3. The emitter of the transistor is connected to one end of the temperature sensor PT100, one end of the capacitor C11, and one end of C14 through inductors L3 and L1 respectively; the other end of the temperature sensor PT100 is connected to the other end of the capacitor C11, one end of the capacitor C15, and one end of the inductor L2 respectively. The other end of the capacitor C14 and the other end of the capacitor C15 are both grounded, and the other end of the inductor L2 is grounded through a resistor R6. One end of the capacitor C13 is connected to the emitter of the transistor, and the other end is connected to the inverting input end of the operational amplifier 1.

[0061] The first sub-filter module is used to effectively suppress the common mode interference at both ends of the temperature sensor PT100, and the second sub-filter module is used to effectively suppress the differential mode interference at both ends of the sensor. Through the joint action of the first sub-filter module and the second sub-filter module, the anti-interference ability of temperature sampling is effectively improved.

[0062] In a specific embodiment, referring to Figure 3 The constant current module 100 further includes: a second filtering module 130 and a third filtering module 140 .

[0063] The third filter module 140 includes capacitors C3 and C5 connected in parallel, one end of the capacitor C3 and one end of C5 are connected to the emitter of the transistor, and the other end of the capacitor C3 and the other end of C5 are connected to the inverting input terminal of the operational amplifier 1. The third filter module 140 is used to further filter out the interference signal at one end of the temperature sensor PT100.

[0064] The second filter module 130 includes capacitors C4 and C6 connected in parallel, and the capacitors C4 and C6 are connected in parallel with the resistor R6. The second filter module 130 is used to further filter out the interference signal at the other end of the temperature sensor PT100.

[0065] The first filter module 120, the second filter module 130 and the third filter module 140 are used together to filter the voltage across the temperature sensor PT100 to obtain a temperature sampling signal. The temperature sampling signal is input into the amplification module 400 in the form of a differential input.

[0066] In a specific embodiment, the amplifying module 400 includes: a first sub-amplifying module 410 , a first isolating module 420 , and a second sub-amplifying module 430 .

[0067] The input end of the first sub-amplifier module 410 is respectively connected to the emitter of the transistor and the inverting input end of the operational amplifier 1, and the output end of the first sub-amplifier module 410 is connected to the input end of the first isolation module 420; the output end of the first isolation module 420 is connected to the input end of the second sub-amplifier module 430; the output end of the second sub-amplifier module 430 is connected to the processing module 500.

[0068] The first sub-amplifier module 410 is used to amplify the temperature sampling signal of the differential input, and is also used to effectively suppress the common mode interference in the signal. The first isolation module 420 is used to isolate and sample the temperature sampling signal after amplification by the first sub-amplifier module 410, so as to isolate the electromagnetic interference and noise interference from other parts such as the driver after the first isolation module 420, and avoid the accuracy error caused by interference. The second sub-amplifier module 430 is used to further amplify the temperature sampling signal after the isolation sampling process of the first isolation module 420 to obtain the temperature sampling signal after the second process. The second process specifically includes the first amplification process, the isolation sampling process, and the second amplification process.

[0069] In a specific embodiment, the first sub-amplification module 410 includes: a second operational amplifier: an operational amplifier 4, a fourth resistor R10, a fifth resistor R11, a sixth resistor R12, and a seventh resistor R13. The emitter of the transistor is connected to the in-phase input terminal of the operational amplifier 4 through the fourth resistor R10, the inverting input terminal of the operational amplifier 1 is connected to the inverting input terminal of the operational amplifier 4 through the fifth resistor R11, the in-phase input terminal of the operational amplifier 4 is also grounded through the sixth resistor R12, the inverting input terminal of the operational amplifier 4 is also connected to the output terminal of the operational amplifier 4 through the seventh resistor R13, and the output terminal of the operational amplifier 4 is connected to the input terminal of the first isolation module 420.

[0070] The operational amplifier 4 , the fourth resistor R10 , the fifth resistor R11 , the sixth resistor R12 , and the seventh resistor R13 constitute a subtractor for converting the differential input temperature sampling signal into a single signal and inputting it into the input end of the first isolation module 420 .

[0071] In a specific embodiment, the first sub-amplification module 410 further includes: a second isolation module. The input end of the second isolation module is respectively connected to the emitter of the transistor and the inverting input end of the first operational amplifier, and the output end of the second isolation module is respectively connected to the in-phase input end and the inverting input end of the operational amplifier 4 through the fourth resistor R10 and the fifth resistor R11.

[0072] Specifically, refer to Figure 3The second isolation module includes a fourth operational amplifier: operational amplifier 2, a fifth operational amplifier: operational amplifier 3, resistors R7, R8, and R9. The non-inverting input terminal of operational amplifier 2 is connected to the emitter of the triode, the non-inverting input terminal of operational amplifier 3 is connected to the inverting input terminal of operational amplifier 1, and the inverting input terminal of operational amplifier 2 is connected to the inverting input terminal of operational amplifier 3 through resistor R7; the inverting input terminal of operational amplifier 2 is connected to the output terminal of operational amplifier 2 through resistor R8; the inverting input terminal of operational amplifier 3 is connected to the output terminal of operational amplifier 3 through resistor R9; the output terminal of operational amplifier 2 is connected to the non-inverting input terminal of operational amplifier 4 through resistor R10, and the output terminal of operational amplifier 3 is connected to the non-inverting input terminal of operational amplifier 4 through resistor R11.

[0073] The second isolation module is used to increase the input impedance of the first sub-amplification module 410 and isolate the temperature sensor PT100 from the subsequent circuit, thereby reducing the influence of the entire amplification module 400 on the loop formed by the constant current module 100 and the temperature sensor PT100.

[0074] In a specific embodiment, referring to Figure 3 The first isolation module 420 includes an isolation optical coupler, and the second sub-amplification module 430 includes a third operational amplifier: an operational amplifier 5, an eighth resistor R14, and a ninth resistor R15.

[0075] The input end of the isolation optocoupler is connected to the output end of the operational amplifier 4, the positive output end of the isolation optocoupler is connected to the in-phase input end of the operational amplifier 5 through the eighth resistor R14, the negative output end of the isolation optocoupler is connected to the inverting input end of the operational amplifier 5 through the ninth resistor R15, and the output end of the operational amplifier 5 is connected to the processing module 500.

[0076] The isolation optocoupler in the first isolation module 420 is powered by the first voltage V1 and the second voltage V2.

[0077] Optionally, the second sub-amplification module 430 also includes capacitors C8 and C9. The capacitor C8 and the resistor R16 are connected in parallel to form a first parallel filtering module for filtering high-frequency interference signals; the capacitor C9 and the resistor R17 are connected in parallel to form a second parallel filtering module for filtering high-frequency interference signals.

[0078] Optionally, the first isolation module 420 further includes a capacitor C7 , and the input end of the isolation optical coupler is grounded via the capacitor C7 . The capacitor C7 is used to filter out interference in the output signal of the operational amplifier 4 .

[0079] In a specific embodiment, referring to Figure 3The processing module 500 includes an MCU microprocessor, a resistor R18, and a capacitor C10. The second sub-amplification module 430 also includes a sixth operational amplifier: operational amplifier 6. The non-inverting input terminal of operational amplifier 6 is connected to the output terminal of operational amplifier 5, and the inverting input terminal of operational amplifier 6 is connected to the output terminal of operational amplifier 6. Operational amplifier 6 is connected to the MCU microprocessor through resistor R18. One end of capacitor C10 is connected to the common node between resistor R18 and MCU microprocessor, and the other end is grounded. The MCU microprocessor is also connected to the vehicle controller. Operational amplifier 6 follows the temperature sampling signal to improve the driving ability of the signal.

[0080] The resistor R18 and the capacitor C10 form a low-pass filter module for filtering out high-frequency signals in the temperature sampling signal output by the operational amplifier 6 .

[0081] The MCU microprocessor is used for performing a first processing on the temperature sampling signal filtered by the low-pass filter module composed of the resistor R18 and the capacitor C10 to obtain the corresponding oil pump temperature.

[0082] The first isolation module 420 eliminates direct electrical connection between the two isolated circuit parts, thereby preventing interference caused by electrical connection.

[0083] According to the characteristics of the PT100 temperature sensor, the resistance value of the thermal resistor varies in a small range, so the amplitude of the pressure difference of the temperature sampling signal changes too small, making it difficult for the MCU microprocessor to collect the data and affecting the sampling accuracy, thereby ensuring the reliability of the oil pump oil temperature detection and improving the anti-interference ability, stability and accuracy of the oil pump oil temperature detection when subjected to strong magnetic field disturbances.

[0084] Optionally, the MCU microprocessor may be a DSP (Digital Signal Processing) digital signal processing module.

[0085] In a specific embodiment, the processing module 500 is further configured to control the operation of the oil pump according to the temperature of the oil pump.

[0086] Specifically, the MCU microprocessor performs a first processing on the temperature sampling signal after high-frequency interference is filtered out to restore the actual oil temperature of the oil pump.

[0087] In addition to collecting the oil pump motor temperature, the MCU microprocessor can also be used to determine whether the current temperature exceeds the set threshold (such as 130°C). If it does not exceed the set value, the oil pump is controlled to operate normally; if it exceeds the set value, the motor is judged to be overheated. The MCU microprocessor sends the over-temperature fault signal and the current temperature value to the vehicle controller through the CAN communication network. The vehicle controller will give the corresponding control strategy according to the vehicle condition to realize the monitoring function of the oil pump oil temperature.

[0088] The present invention adopts a three-terminal adjustable parallel regulator, an operational amplifier, and a triode to form a simple adjustable constant current circuit to provide a constant current for the temperature sensor, so that the oil pump temperature and the temperature sampling signal are in a stable linear relationship. The constant current generation circuit is simple, easy to implement, and low in cost, ensuring the accuracy and stability of the oil pump temperature measurement. The temperature sensor input signal is input into the DSP digital signal processor after being processed by the filter circuit, the amplifier circuit, the optical coupling isolation amplifier, and the filter circuit, so as to realize real-time and accurate measurement of the oil pump motor, effectively suppress the common mode interference, differential mode interference and other interferences at both ends of the temperature sensor, improve the anti-interference ability of the oil pump temperature sampling signal, ensure the accuracy and reliability of the oil pump temperature detection system, and ensure the reliable operation of the whole vehicle.

[0089] Figure 4 FIG. 1 is a flow chart of a temperature monitoring method in an embodiment. Figure 4 , the present application provides a temperature monitoring method, the method comprising the following steps:

[0090] S100: Obtain the oil pump temperature.

[0091] S200: Compare the oil pump temperature with a preset threshold to obtain a comparison result.

[0092] S300: Obtaining a corresponding control strategy according to the comparison result.

[0093] S400: Control the temperature of the oil pump according to the control strategy.

[0094] Step S100 specifically includes: acquiring a temperature sampling signal; and performing a first processing on the temperature sampling signal to obtain a corresponding oil pump temperature.

[0095] The method of obtaining the temperature sampling signal specifically includes obtaining the temperature sampling signal through the temperature detection circuit described above. The method can be applied to the temperature monitoring of the oil pump of an electric vehicle.

[0096] The execution body of the method may be the processing module mentioned above. The processing module compares the oil pump temperature with a preset threshold to obtain a comparison result, obtains a corresponding control strategy according to the comparison result, and controls the temperature of the oil pump according to the control strategy.

[0097] The control strategy is that when the comparison result is that the oil pump temperature is less than the preset threshold, the oil pump is controlled to work normally. When the comparison result is that the oil pump temperature is greater than or equal to the preset threshold, the processing module sends the over-temperature fault signal and the current temperature value to the vehicle controller through the CAN communication network. The vehicle controller controls the operation of the oil pump to achieve the purpose of controlling the oil pump temperature.

[0098] In one embodiment, the present application also provides an electric vehicle, which includes the temperature detection circuit described in any one of the above items.

[0099] In a specific embodiment, the electric vehicle controls the temperature of the oil pump according to the temperature monitoring method described above, that is, the temperature of the oil pump is monitored.

[0100] It should be noted that, in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0101] The foregoing is merely a specific embodiment of the present invention, which enables those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A temperature detection circuit, characterized in that: include: Temperature sensor, constant current module, processing module; The constant current module is connected to the temperature sensor and is used to provide a constant current to the temperature sensor; The processing module is connected to the temperature sensor, and is used to obtain a temperature sampling signal of the temperature sensor, and perform a first processing on the temperature sampling signal to obtain a corresponding oil pump temperature; Wherein, the temperature sampling signal is determined by the resistance value of the temperature sensor and the constant current; The circuit further includes an amplification module between the temperature sensor and the processing module; The amplification module is used for performing a second process on the temperature sampling signal to obtain a second processed temperature sampling signal; The processing module is specifically used to obtain the temperature sampling signal after the second processing, and perform a first processing on the temperature sampling signal after the second processing to obtain the corresponding oil pump temperature; The constant current module includes: a first power supply, a constant voltage source module, a first operational amplifier, a first resistor, a triode, a second resistor, and a third resistor; The output end of the constant voltage source module is connected to the non-inverting input end of the first operational amplifier, the inverting input end of the first operational amplifier is grounded through the first resistor, the base of the transistor is connected to the output end of the first operational amplifier through the second resistor, the collector of the transistor is connected to the first power supply through the third resistor, and the emitter of the transistor is grounded through the temperature sensor and the first resistor in sequence; the first power supply, the third resistor, the transistor, the temperature sensor, and the first resistor are electrically connected to the ground in sequence to form a closed loop.

2. The circuit according to claim 1, characterized in that The constant current module also includes: a first filtering module; The first side of the first filter module is connected between the emitter of the transistor and the first end of the temperature sensor, and the second side of the first filter module is connected between the inverting input end of the first operational amplifier and the second end of the temperature sensor.

3. The circuit according to claim 1 or 2, characterized in that: The constant current module also includes: a second filtering module and a third filtering module; The second filtering module is connected in parallel with the first resistor; One end of the third filter module is connected to the emitter of the transistor, and the other end is connected to the inverting input end of the first operational amplifier.

4. The circuit according to claim 1, characterized in that The amplification module comprises: a first sub-amplification module, a first isolation module, and a second sub-amplification module; The input end of the first sub-amplifier module is connected to the emitter of the transistor and the inverting input end of the first operational amplifier respectively, and the output end of the first sub-amplifier module is connected to the input end of the first isolation module; The output end of the first isolation module is connected to the input end of the second sub-amplification module; The output end of the second sub-amplifier module is connected to the processing module.

5. The circuit according to claim 4, characterized in that The first sub-amplification module includes: a second operational amplifier, a fourth resistor, a fifth resistor, a sixth resistor, and a seventh resistor. The emitter of the transistor is connected to the non-inverting input terminal of the second operational amplifier through the fourth resistor, the inverting input terminal of the first operational amplifier is connected to the inverting input terminal of the second operational amplifier through the fifth resistor, the non-inverting input terminal of the second operational amplifier is also grounded through the sixth resistor, the inverting input terminal of the second operational amplifier is also connected to the output terminal of the second operational amplifier through the seventh resistor, and the output terminal of the second operational amplifier is connected to the input terminal of the first isolation module.

6. The circuit according to claim 5, characterized in that The first sub-amplification module further includes: a second isolation module; The input end of the second isolation module is respectively connected to the emitter of the transistor and the inverting input end of the first operational amplifier, and the output end of the second isolation module is respectively connected to the non-inverting input end and the inverting input end of the second operational amplifier through the fourth resistor and the fifth resistor.

7. The circuit according to claim 4, characterized in that The first isolation module includes an isolation optical coupler, and the second sub-amplification module includes a third operational amplifier, an eighth resistor, and a ninth resistor; The input end of the isolation optocoupler is connected to the output end of the second operational amplifier, the positive output end of the isolation optocoupler is connected to the non-inverting input end of the third operational amplifier through the eighth resistor, the negative output end of the isolation optocoupler is connected to the inverting input end of the third operational amplifier through the ninth resistor, and the output end of the third operational amplifier is connected to the processing module.

8. The circuit according to claim 1, characterized in that The processing module is further used to control the operation of the oil pump according to the temperature of the oil pump.

9. A temperature monitoring method, characterized in that: The method comprises: Acquiring the oil pump temperature according to the temperature detection circuit according to any one of claims 1 to 8; Comparing the oil pump temperature with a preset threshold to obtain a comparison result; Acquire a corresponding control strategy according to the comparison result; The temperature of the oil pump is controlled according to the control strategy.

10. An electric vehicle, characterized in that: The temperature detection circuit comprises the temperature detection circuit described in any one of claims 1 to 8.

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