A motor controller and its motor temperature sampling circuit

Abstract

The present invention provides a motor controller and its motor temperature sampling circuit. The motor temperature sampling circuit includes a main sampling branch and an auxiliary sampling branch. The input ends of both are connected to the output end of the motor temperature sensor, and the output ends of both are respectively connected to two input ends of a processor in the motor controller. Moreover, the main sampling branch includes a differential amplification link that the auxiliary sampling branch does not have. Therefore, the auxiliary sampling branch can respond to the change of the output voltage of the temperature sensor faster than the main sampling branch. The two output signals are compared in real time in the processor. When the motor temperature sensor has a disconnection, the difference between the two output signals is greater than a preset threshold, thereby realizing the rapid detection of the disconnection of the temperature sensor line. Moreover, the motor temperature sampling circuit can also automatically identify the sensor model by adjusting the voltage division parameters and the gain coefficient of the differential amplification link.

Description

Technical Field

[0001] The present invention relates to the field of power electronics technology, and particularly relates to a motor controller and its motor temperature sampling circuit. Background Art

[0002] In new energy vehicles, the motor and its motor control are key powertrain components. Since overheating of the stator or permanent magnet in the motor will greatly affect the motor life and even pose a safety hazard, the motor controller must be able to accurately collect the temperature of the motor.

[0003] Although the existing motor temperature sampling circuits can meet certain collection accuracy, due to the lack of full consideration of the special working conditions of the motor controller and the motor assembly in the complex vibration environment of the whole vehicle, there are situations where the temperature sensor wire harness is in poor contact or disconnected. Therefore, these circuits have not well solved the rapid detection of the open circuit of the temperature sensor line during the operation of electric vehicles. Summary of the Invention

[0004] In view of this, the present invention provides a motor controller and its motor temperature sampling circuit to achieve rapid detection of the open circuit of the temperature sensor line.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] The first aspect of the present invention provides a motor temperature sampling circuit for a motor controller, including: a main sampling branch and an auxiliary sampling branch; wherein,

[0007] The input ends of the main sampling branch and the auxiliary sampling branch are both connected to the output end of the motor temperature sensor;

[0008] The output ends of the main sampling branch and the auxiliary sampling branch are respectively connected to two input ends of a processor in the motor controller in a corresponding manner;

[0009] The main sampling branch includes a differential amplification link that is not available in the auxiliary sampling branch, so that when the motor temperature sensor has a disconnection, the difference between the output signals of the main sampling branch and the auxiliary sampling branch is greater than a preset threshold.

[0010] Optionally, the auxiliary sampling branch includes: a first voltage dividing circuit, a first low-pass filter, and a first ADC converter connected in series in sequence;

[0011] The input end of the first voltage dividing circuit is used as the input end of the auxiliary sampling branch;

[0012] The output end of the first ADC converter is used as the output end of the auxiliary sampling branch.

[0013] Optionally, the auxiliary sampling branch further includes: a signal follower disposed between the first voltage dividing circuit and the first low-pass filter.

[0014] Optionally, the main sampling branch includes, connected in series in sequence: a second voltage dividing circuit, an operational amplifier, a second low-pass filter, and a second ADC converter;

[0015] The input end of the second voltage dividing circuit serves as the input end of the main sampling branch;

[0016] The output end of the second ADC converter serves as the output end of the main sampling branch.

[0017] Optionally, a first resistor, a second resistor, and a third resistor are connected in series in sequence between the power supply and the ground; where

[0018] The first resistor is connected to the power supply, and the third resistor is grounded;

[0019] Both ends of the second resistor serve as the input end of the first voltage dividing circuit and the input end of the second voltage dividing circuit;

[0020] The connection point between the first resistor and the second resistor serves as the output end of the second voltage dividing circuit;

[0021] The connection point between the second resistor and the third resistor serves as the output end of the first voltage dividing circuit.

[0022] Optionally, a voltage dividing resistor selection and matching module is further connected in parallel at both ends of the first resistor;

[0023] The resistance value of the voltage dividing resistor selection and matching module is controlled by the processor.

[0024] Optionally, the voltage dividing resistor selection and matching module includes: at least one series branch;

[0025] The series branch includes a first switch and a fourth resistor connected in series;

[0026] The series branch is connected in parallel with the first resistor;

[0027] The on / off of the first switch is controlled by the processor.

[0028] Optionally, the operational amplifier is an operational amplifier with adjustable gain, and its gain adjustment terminal is connected to the processor through a digital switch module, so that the processor can adjust the gain amount of the operational amplifier by selecting a channel in the digital switch module.

[0029] Optionally, the channel includes: a second switch, a fifth resistor, a sixth resistor, and a seventh resistor;

[0030] The control terminal of the second switch is connected to the control terminal of the channel through the fifth resistor;

[0031] The sixth resistor is connected between the input terminal of the second switch and the power supply, and the input terminal of the second switch is connected to the corresponding gain adjustment terminal of the operational amplifier;

[0032] One end of the seventh resistor is connected to the control terminal of the second switch, and the other end is connected to the output terminal of the second switch and the ground.

[0033] The second aspect of the present invention further provides a motor controller, including: a processor and the motor temperature sampling circuit of the motor controller described in any paragraph of the above first aspect.

[0034] The motor temperature sampling circuit of the motor controller provided by the present invention includes a main sampling branch and an auxiliary sampling branch. The input ends of both are connected to the output end of the motor temperature sensor, and the output ends of both are respectively connected to two input ends of the processor in the motor controller; moreover, the main sampling branch includes a differential amplification link that the auxiliary sampling branch does not have. That is, the auxiliary sampling branch can quickly respond to the change in the output voltage of the temperature sensor, while the response of the main sampling branch to this change will lag behind the auxiliary sampling branch; the two output signals can be compared in real time in the processor. When the motor temperature sensor has a disconnection, the difference between the two output signals is greater than a preset threshold, and thus can be used by the processor as a basis for determining that the temperature sensor line is open, realizing the rapid detection of the temperature sensor line break. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings to be used in the description of the embodiments or the prior art. Obviously, the following drawings are only the embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained according to the provided drawings.

[0036] Figures 1 to 3 They are respectively three schematic structural diagrams of the motor temperature sampling circuit of the motor controller provided by the embodiments of the present invention;

[0037] Figure 4 and Figure 5 They are respectively two circuit diagrams of the shared voltage dividing circuit in the motor temperature sampling circuit provided by the embodiments of the present invention;

[0038] Figure 6 It is the specific circuit diagram of the motor temperature sampling circuit provided by the embodiment of the present invention;

[0039] Figure 7A flow chart of automatically identifying sensor models provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] In this application, the terms "comprises", "comprising" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising 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, an element defined by the sentence "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element.

[0042] With regard to the situation that the temperature sensor harness has poor contact and is disconnected, the motor temperature sampling circuit in the prior art fails to achieve timely detection. At least in certain power ranges of the motor operation, when the thermistor in the temperature sensor is disconnected, the resistance value fed back by the thermistor cannot be expressed in real time by the vehicle-wide predicted temperature detection failure signal of the motor controller. Therefore, based on the defects in circuit sampling in the prior art, the present invention provides a motor temperature sampling circuit of a motor controller to achieve rapid detection of temperature sensor circuit breaks.

[0043] like Figure 1 As shown, the motor temperature sampling circuit of the motor controller includes: a main sampling branch 20 and an auxiliary sampling branch 10; wherein:

[0044] The input end of the main sampling branch 20 and the input end of the auxiliary sampling branch 10 are both connected to the output end of the motor temperature sensor 30. The thermistor in the motor temperature sensor 30 can be a PTC (Positive Temperature Coefficient) resistor, i.e., a thermistor whose resistance gradually increases with increasing temperature; or, it can be an NTC (Negative Temperature CoeffiCient), i.e., a thermistor whose resistance gradually decreases with increasing temperature; the more common ones are PT1000, PT100 and KTY84 series thermistors, which can be determined according to their specific application environment and are all within the protection scope of this application.

[0045] The output ends of the main sampling branch 20 and the auxiliary sampling branch 10 are respectively and correspondingly connected to two input ends of the processor 40 in the motor controller. In practical applications, the processor 40 can be an MCU (Microcontroller Unit), that is, a microprocessor device capable of implementing functions such as software programming, ADC (Analog-to-Digital Converter) reading, and IO (Input / Output) output of different configured electrical levels; alternatively, the processor 40 can also be a DSP (Digital Signal Processing / Processor), but it is not limited thereto, and it can be determined according to its specific application environment, and all are within the protection scope of this application.

[0046] The main sampling branch 20 includes a differential amplification link that the auxiliary sampling branch 10 does not have. In this way, the auxiliary sampling branch 10 can quickly respond to the change in the output voltage of the temperature sensor, while in the main sampling branch 20, due to the setting of the differential amplification link, the response of its output signal to the change in the output voltage of the temperature sensor will lag behind the auxiliary sampling branch 10; if the motor temperature sensor 30 has a disconnection, the difference between the output signals of the main sampling branch 20 and the auxiliary sampling branch 10 is greater than a preset threshold, and thus can be used by the processor 40 as a basis for determining the disconnection of the temperature sensor line; that is, after the two output signals are compared in real time in the processor 40, a determination of rapid disconnection detection can be made through a software algorithm, and the result of the disconnection of the temperature sensor line can be obtained, for example, it can be represented by a vehicle pre-judgment temperature detection failure signal.

[0047] For the motor temperature sampling circuit of the motor controller provided in this embodiment, the realization of the motor temperature disconnection detection function is mainly achieved by dividing the motor temperature detection into two-way ADC sampling, and then the processor 40 reads the sampling values of the two-way ADC in real time. If the temperature difference between the two-way fitting exceeds a certain set temperature range value, the system can quickly determine that the connection state of the thermistor of the motor temperature sensor is abnormal, thereby realizing the disconnection detection function; it helps to identify the disconnection detection of the motor temperature sensor wiring harness, which is beneficial to the protection of abnormal situations of the motor.

[0048] It is worth noting that for the motor temperature sensor used in new energy vehicles, in a vibration environment, the sensor wiring harness is prone to looseness, and the prior art cannot accurately detect and feedback the connection state of the sensor wiring harness. However, through the above principle, this embodiment can meet the operating conditions of the harsh vibration of the vehicle, ensure the reliable long-term application of the temperature detection function, and therefore this circuit can be applied to new energy vehicles.

[0049] On the basis of the previous embodiment, see Figure 2, which gives a specific optional structure of the motor temperature sampling circuit, where:

[0050] The auxiliary sampling branch 10 includes, connected in series in sequence: a first voltage dividing circuit 101, a first low-pass filter 102, and a first ADC converter 103; the input end of the first voltage dividing circuit 101 serves as the input end of the auxiliary sampling branch 10; the output end of the first ADC converter 103 serves as the output end of the auxiliary sampling branch 10.

[0051] Preferably, referring to Figure 3 , the auxiliary sampling branch 10 further includes: a signal follower 104 provided between the first voltage dividing circuit 101 and the first low-pass filter 102.

[0052] Figure 3 For the auxiliary sampling branch 10 shown in, after adding one stage of differential filtering to the divided voltage signal output by the first voltage dividing circuit 101 and then sampling, the fast response and reading functions of the temperature ADC can be realized. However, if it is used alone, when the connection of the temperature sensor wire harness is abnormal, the detection and reporting functions cannot be realized.

[0053] Therefore, at this time, a main sampling branch 20 is set to work simultaneously with the auxiliary sampling branch 10, and as shown in Figure 2 or Figure 3 , the main sampling branch 20 specifically includes, connected in series in sequence: a second voltage dividing circuit 201, an operational amplifier 202, a second low-pass filter 203, and a second ADC converter 204; the input end of the second voltage dividing circuit 201 serves as the input end of the main sampling branch 20; the output end of the second ADC converter 204 serves as the output end of the main sampling branch 20.

[0054] In this way, since the operational amplifier 202 affects the speed in the signal transmission process, the output signal of the main sampling branch 20 will lag behind the auxiliary sampling branch 10, and then the wire break detection function of the motor temperature sensor is realized through the difference between the two.

[0055] In order to reduce the device composition, the main sampling branch 20 and the auxiliary sampling branch 10 can share some sampling resistors. Specifically, as shown in Figure 4 , between the power supply VCC and the ground GND, there are connected in series in sequence: a first resistor R1, a second resistor R2, and a third resistor R3; where:

[0056] The first resistor R1 is connected to the power supply VCC, and the third resistor R3 is grounded to GND.

[0057] Both ends of the second resistor R2 serve as the input end of the first voltage dividing circuit 101 and the input end of the second voltage dividing circuit 201, and are connected to both ends of the thermistor in the motor temperature sensor 30.

[0058] The connection point of the first resistor R1 and the second resistor R2 serves as the output terminal of the second voltage dividing circuit 201.

[0059] The connection point of the second resistor R2 and the third resistor R3 serves as the output terminal of the first voltage dividing circuit 101.

[0060] In practical applications, corresponding grounding capacitors can be respectively provided at the output terminals of the two voltage dividing circuits to realize the access of the output signal of the thermistor in the motor temperature sensor 30.

[0061] In this embodiment, based on the principle that the resistance value of the motor temperature sensor 30 changes substantially linearly with temperature, the above voltage dividing circuit is designed, and the voltage dividing levels are sampled at both ends of the motor temperature sensor 30. These two levels can independently look up the table and fit the corresponding resistance temperature, and the two temperatures are further compared and calculated to determine whether the resistance connection wire harness is abnormal.

[0062] It should be noted that since the motor controller and the motor are generally separate products, often one controller is often adapted to use multiple motors, and even the control boards inside some controllers are platform-based products that can be synchronously applied to multiple controller products; however, for the temperature sensors located inside the motor, different manufacturers' motors have their own selection principles, and their models vary widely. The existing motor temperature sampling circuits have poor compatibility and matching, and even need to re-match the hardware circuits; therefore, in order to improve the applicability of the controller, if the motor temperature sampling circuit can achieve automatic matching of different motor temperature sensor models, the design and maintenance costs can be reduced.

[0063] Based on this, in this embodiment Figure 4 On the basis of the embodiment shown, preferably, as Figure 5 shown, for this motor temperature sampling circuit, a voltage dividing resistor selection and matching module 205 is further connected in parallel at both ends of the first resistor R1; the resistance value of the voltage dividing resistor selection and matching module 205 is controlled by the processor 40.

[0064] Specifically, the voltage dividing resistor selection and matching module 205 may include: at least one series branch ( Figure 5 one series branch is shown as an example in

[0065] For Figure 5Taking the shown structure as an example for illustration, Thermistor1 and Thermistor2 are the output signals of the motor temperature sensor 30, which can be compatible with common PTC resistors and NTC resistors. PTC_EN is a switching control signal from the processor 40 to realize the transformation of the voltage-dividing resistor parameters; when the first switch K1 is turned on, the fourth resistor R4 in series with it will be in parallel with the first resistor R1, causing the equivalent resistance value between the power supply VCC and Thermistor1 to change, and further changing the voltage-dividing parameters of the two voltage-dividing circuits.

[0066] More preferably, the operational amplifier 202 can also be an operational amplifier 202 with adjustable gain, and its gain adjustment terminals (such as Figure 6 G0, G1, and G2 shown in

[0067] are connected to the processor 40 through the digital switch module 206, so that the processor 40 can adjust the gain of the operational amplifier 202 by selecting the channels in the digital switch module 206.

[0068] It should be noted that in order to realize the control of the first switch K1 by the processor 40, corresponding channels can also be set in the digital switch module 206 to generate and output the switch control signal PTC_EN. When there are multiple series branches in the voltage-dividing resistor selection module 205, corresponding numbers of channels need to be set in the digital switch module 206 to respectively control the on / off of each first switch K1 to realize the segmented switching of the voltage-dividing parameters.

[0069] Figure 5 and Figure 6 The first switch K1 and each second switch K2 shown in

[0070] Specifically, referring to Figure 6, the processor 40 outputs four control signals to the digital switch module 206 through its four IO ports DSP_IO1, DSP_IO2, DSP_IO3, and DSP_IO4, namely: a control signal PTC_EN_DSP for the voltage-dividing resistor selection module 205, and three control signals PTC_EN_G0, PTC_EN_G1, and PTC_EN_G2 for the operational amplifier 202. Inside the digital switch module 206: The first channel receives the control signal PTC_EN_DSP, generates and outputs a switch control signal PTC_EN to the control terminal of the first switch K1; the second channel receives the control signal PTC_EN_G2, generates and outputs a gain adjustment signal G2 to the gain adjustment terminal G2 of the operational amplifier 202; the third channel receives the control signal PTC_EN_G1, generates and outputs a gain adjustment signal G1 to the gain adjustment terminal G1 of the operational amplifier 202; the fourth channel receives the control signal PTC_EN_G0, generates and outputs a gain adjustment signal G0 to the gain adjustment terminal G0 of the operational amplifier 202.

[0071] The gain-adjustable operational amplifier 202 is an amplifier device with a configuration switch (such as Figure 6 each of the second switches K2 shown), and by giving different logic levels to the configuration switch, specifically through three channels inside the digital switch module 206, three transistor-transistor logic level TTL signal level logic outputs are respectively realized, and then amplifiers with various required magnification factors are realized.

[0072] Figure 6Other modules within the motor temperature sampling circuit are also specifically shown. Among them, the first voltage division circuit 101 and the second voltage division circuit 201 are voltage division resistor circuits in which the thermistor is connected to the control board. This part requires the resistance value of the voltage division resistor to be as accurate as possible. At the same time, since different thermistors exhibit different impedance values in certain temperature ranges, the selection and calculation of the voltage division resistor value are particularly crucial. The subsequent amplifier circuit and resistor changer are compensations made to adjust the resistance value of the voltage division resistor circuit. The operational amplifier 202 is an amplifier circuit with adjustable gain. In order to make up for the accurate sampling of the voltage division value parameter, the gain is reasonably increased, and then the output range of the ADC converter 204 is compensated. The second low-pass filter 203 and the first low-pass filter 102 mainly eliminate high-frequency interference and improve the sampling accuracy of the processor 40. The digital switch module 206 is mainly a digital conversion switch circuit to achieve the switching of the required gain of the amplifier. The processor 40 mainly realizes the conversion of the digital switch and the reading and calculation of the ADC signal; the voltage division resistor selection and matching module 205 is a compensation conversion circuit for the voltage division resistor value to achieve the segmented switching of the level value. The output signal Motor_Temp_AD0 of the second low-pass filter 203 is connected to the DSP_ADC1 pin of the processor 40 through the second ADC converter 204; the output signal Motor_Temp_AD1 of the first low-pass filter 102 is connected to the DSP_ADC2 pin of the processor 40 through the first ADC converter 103.

[0073] To achieve the automatic identification function of the motor temperature sensor, first, the configuration of the hardware circuit parameters must meet the design requirements of conventional series temperature sensors or thermistors, etc., within the working range. At the same time, the signal reception level of the processor 40 must also meet the corresponding accuracy range that it can satisfy. This automatic identification detection function is to maximize the sampling accuracy of the signal reception level of the processor 40, reasonably and automatically select and configure the gain coefficient of the voltage division resistor and the operational amplifier. The implementation method of the automatic identification is shown in Figure 7As shown in the figure, the specific process is as follows: At room temperature, configure the parameters of each sensor first. These parameters can be selected through the hardware circuit. That is to say, conduct experiments in advance with the hardware circuit, calculate the voltage-dividing resistors and gain coefficients suitable for the thermistors in the motor temperature sensors 30 of various models (such as PT1000 / PT100 / KTY84, etc.) at room temperature, and calibrate the temperature calculation table based on them. Then, use software to implant the calibrated temperature calculation table into the program in the processor 40, so that an automatic recognition algorithm can be performed according to each sensor parameter in the program. When actually operating, pass the motor to be measured through the 25°C cooling water liquid, set the program to enter the sensor automatic recognition mode, and the processor 40 can automatically find the corresponding matching calculation and sensor model recognition according to the previous algorithm. In the sensor automatic recognition mode, the processor 40 will adjust the voltage-dividing resistor and gain coefficient according to the experimental results, determine the voltage-dividing resistor and gain coefficient that can obtain the sampling value at 25°C, and then obtain which sensor resistor is used by the current motor to be measured. Then, according to the automatically recognized model, the software writes the calibrated parameters to call the corresponding hardware configuration mode and the on-road ADC output acquisition function, and the sensor model recognition and its SMS detection function are completed. This sensor automatic recognition function helps to find and identify the motor temperature sensor model in a specific mode, which is convenient for developers to conduct research.

[0074] In this embodiment, at room temperature, an amplifier circuit with adjustable gain is used for sampling and calculation. According to the collected and calculated temperature values, the corresponding motor internal temperature sensor model is fitted. Based on the special relationship between the resistance values of the commonly used PTC series and NTC series changing with temperature, the processor 40 configures a reasonable voltage-dividing sampling resistor through a selection switch to achieve the purpose of accurately collecting the motor temperature. At the same time, it automatically recognizes and identifies the sensor model, solves the problem that the temperature sensor cannot be directly adapted in the motor controller's compatible application in multi-platform motor drives, helps the compatibility of multiple sensors, has a simple implementation method, and high temperature collection accuracy. Moreover, it is convenient for the general management of the motor controller control board hardware and reduces the control board management cost.

[0075] In addition, in this embodiment, the processor 40 is used to select the corresponding analog switch circuit, so as to quickly find the corresponding matching voltage-dividing resistor, and can also effectively increase the output voltage range. Selecting and configuring an operational amplifier 202 with adjustable gain to configure the circuit can also improve the anti-interference ability of the output voltage and match an effective amplified level output.

[0076] Another embodiment of the present invention also provides a motor controller, which includes: a processor and the motor temperature sampling circuit as described in any of the above embodiments.

[0077] For the structure and working principle of this motor temperature sampling circuit, refer to the above embodiments, and details will not be repeated here.

[0078] By using the motor temperature sampling circuit described in the above embodiments, it is possible to quickly detect the line break of the motor temperature sensor. Moreover, by automatically adjusting the internal parameters of the motor temperature sampling circuit by the processor, it is possible to automatically identify the sensor type and achieve the function of accurately collecting the motor temperature.

[0079] In this specification, the same or similar parts among the various embodiments can be referred to each other, and the key points of each embodiment are the differences from other embodiments. In particular, for a system or a system embodiment, since it is basically similar to a method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment. The systems and system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. A person of ordinary skill in the art can understand and implement it without creative work.

[0080] Those skilled in the art can further realize that the units and algorithm steps of each example described in combination with the embodiments disclosed in this article can be implemented by electronic hardware, computer software, or a combination of the two. To clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described according to functions in the above description. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Skilled professionals can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present invention.

[0081] Regarding the above description of the disclosed embodiments, the features recorded in each embodiment of this specification can be replaced or combined with each other, enabling those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can 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 these embodiments shown in this article, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A motor temperature sampling circuit for a motor controller, characterized in that, Comprising: A main sampling branch and an auxiliary sampling branch; wherein, The input ends of the main sampling branch and the auxiliary sampling branch are both connected to the output end of the motor temperature sensor; The output ends of the main sampling branch and the auxiliary sampling branch are respectively and correspondingly connected to two input ends of the processor in the motor controller; The main sampling branch includes a differential amplification link that the auxiliary sampling branch does not have, so that when the motor temperature sensor has a disconnection situation, the difference between the output signals of the main sampling branch and the auxiliary sampling branch is greater than a preset threshold.

2. The motor temperature sampling circuit for a motor controller according to claim 1, characterized in that, The auxiliary sampling branch includes, connected in series in sequence: a first voltage dividing circuit, a first low-pass filter, and a first ADC converter; The input end of the first voltage dividing circuit serves as the input end of the auxiliary sampling branch; The output end of the first ADC converter serves as the output end of the auxiliary sampling branch.

3. The motor temperature sampling circuit for a motor controller according to claim 2, characterized in that, The auxiliary sampling branch further includes: a signal follower disposed between the first voltage dividing circuit and the first low-pass filter.

4. The motor temperature sampling circuit for a motor controller according to claim 2 or 3, characterized in that, The main sampling branch includes, connected in series in sequence: a second voltage dividing circuit, an operational amplifier, a second low-pass filter, and a second ADC converter; The input end of the second voltage dividing circuit serves as the input end of the main sampling branch; The output end of the second ADC converter serves as the output end of the main sampling branch.

5. The motor temperature sampling circuit for a motor controller according to claim 4, characterized in that, A first resistor, a second resistor, and a third resistor are connected in series in sequence between the power supply and the ground; wherein, The first resistor is connected to the power supply, and the third resistor is grounded; Both ends of the second resistor serve as the input end of the first voltage dividing circuit and the input end of the second voltage dividing circuit; The connection point between the first resistor and the second resistor serves as the output end of the second voltage dividing circuit; The connection point between the second resistor and the third resistor serves as the output end of the first voltage dividing circuit.

6. The motor temperature sampling circuit for a motor controller according to claim 5, characterized in that, A voltage dividing resistor selection and matching module is further connected in parallel at both ends of the first resistor; The resistance value of the voltage dividing resistor selection and matching module is controlled by the processor.

7. The motor temperature sampling circuit for a motor controller according to claim 6, characterized in that, The voltage dividing resistor selection and matching module includes: at least one series branch; The series branch includes a first switch and a fourth resistor connected in series; The series branch is connected in parallel with the first resistor; The on / off of the first switch is controlled by the processor.

8. The motor temperature sampling circuit for a motor controller according to claim 6, characterized in that, The operational amplifier is an operational amplifier with adjustable gain, and its gain adjustment end is connected to the processor through a digital switch module, so that the processor adjusts the gain amount of the operational amplifier by selecting a channel in the digital switch module.

9. The motor temperature sampling circuit for a motor controller according to claim 8, characterized in that, The channel includes: a second switch, a fifth resistor, a sixth resistor, and a seventh resistor; The control end of the second switch is connected to the control end of the channel through the fifth resistor; The sixth resistor is connected between the input end of the second switch and the power supply, and the input end of the second switch is connected to the corresponding gain adjustment end of the operational amplifier; One end of the seventh resistor is connected to the control end of the second switch, and the other end is connected to the output end of the second switch and the ground.

10. A motor controller, characterized in that, Comprising: A processor and a motor temperature sampling circuit of the motor controller according to any one of claims 1 to 9.

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