A compatible resolver matching circuit for xEV inverters

Abstract

The present invention provides a compatible rotary transformer matching circuit suitable for an xEV inverter, characterized in that it includes an excitation signal generating module, an excitation amplifying module, a rotary transformer, a sine-cosine signal buffer circuit and a microcontroller, the excitation signal generating module is connected to the excitation amplifying module, the excitation amplifying module is connected to the rotary transformer, the output end of the rotary transformer is connected to the sine-cosine signal buffer circuit, and the sine-cosine signal buffer circuit is connected to the microcontroller; the advantages of the present invention are: by utilizing signal modulation and external discrete component circuits, the generation of a rotary transformer excitation signal is achieved in a low-cost manner, thereby reducing system costs; the compatible sine-cosine signal buffer circuit design can support the requirements of isolated and non-isolated rotary transformers for matching circuits; the excitation signal amplifying circuit has a complete overcurrent protection function and can achieve active shutdown, and the solution is simple and reliable, and is easy to implement and promote in mass production.

Description

Technical Field

[0001] The present invention relates to the field of new energy vehicles, and in particular to a compatible rotary transformer matching circuit suitable for an xEV inverter. Background Art

[0002] In recent years, with the increasing prominence of environmental issues, the continuous rise in oil prices and the national policy support for new energy vehicles, more and more people have begun to choose new energy vehicles as a means of transportation. Whether it is a hybrid or a pure electric vehicle, the motor drive system is an important power source for the entire vehicle, which directly affects the vehicle's power performance, comfort and energy utilization.

[0003] At present, most of the drive motors of new energy vehicles use permanent magnet synchronous motors. In the permanent magnet synchronous motor control system, the angle of the rotor is required for coordinate transformation and speed calculation. The most commonly used rotor angle measurement method is to use a photoelectric encoder or a resolver. In the existing circuit solutions for resolvers, most of them use dedicated integrated chips (such as AD2S1210) to generate a pair of complementary excitation signals, which are input to the excitation end of the resolver through signal and power amplification. Then the dedicated integrated chip identifies the sine and cosine signals returned by the resolver, and calculates the direction, angle and speed of the rotor, and then transmits them to the MCU through the communication interface.

[0004] The solution using a dedicated integrated chip has a relatively simple circuit design and is conducive to simplifying the software algorithm. However, its disadvantages cannot be ignored: first, the price of the dedicated integrated chip is relatively high, which will inevitably increase the cost of the entire drive system; second, the sine and cosine signals returned by the resolver are resolved by the dedicated integrated chip and transmitted through the communication line before being input into the MCU, and the signal delay in the middle is relatively large. Summary of the invention

[0005] The object of the present invention is to provide a compatible rotary transformer matching circuit suitable for an xEV inverter, which is compatible with isolated and non-isolated rotary transformers and has an overcurrent protection function.

[0006] In order to achieve the above object, the technical solution of the present invention is:

[0007] A compatible rotary transformer matching circuit suitable for an xEV inverter, characterized in that it includes an excitation signal generating module, an excitation amplifying module, a rotary transformer, a sine-cosine signal buffer circuit and a microcontroller, wherein the output end of the excitation signal generating module is connected to the input end of the excitation amplifying module, the output end of the excitation amplifying module is connected to the input end of the rotary transformer, the output end of the rotary transformer is connected to the input end of the sine-cosine signal buffer circuit, and the output end of the sine-cosine signal buffer circuit is connected to the input end of the microcontroller.

[0008] Furthermore, the excitation signal generating module comprises a first resistor, one end of which inputs a positive phase waveform, the other end of which is respectively connected to one end of a first capacitor and a second capacitor, and the other end of the second capacitor is grounded;

[0009] The excitation signal generating module comprises a fifth resistor, one end of which is input with an inverted waveform, the other end of which is respectively connected with one end of the third capacitor and one end of the fourth capacitor, and the other end of the fourth capacitor is grounded.

[0010] Further, the excitation amplification module includes a first operational amplifier, the other end of the first capacitor is connected to the inverting input end of the first operational amplifier, the inverting input end of the first operational amplifier is connected to one end of the second resistor, the other end of the second resistor is connected to one end of the third resistor and the fourth resistor, the other end of the third resistor and the fourth resistor and the output end of the first operational amplifier are all connected to a first overcurrent protection module, the first overcurrent protection module is respectively connected to the base of the first triode and the second triode, the collector of the first triode is connected to the voltage input, the collector of the second triode is grounded, the emitters of the first triode and the second triode are connected to the other end of the third resistor and the fourth resistor, and one end of the third resistor and the fourth resistor is used as a positive phase output;

[0011] The excitation amplification module also includes a second operational amplifier, the other end of the third capacitor is connected to the inverting input end of the second operational amplifier, the inverting input end of the second operational amplifier is connected to one end of the sixth resistor, the other end of the sixth resistor is connected to one end of the seventh resistor and the eighth resistor, the other end of the seventh resistor and the eighth resistor and the output end of the second operational amplifier are all connected to the second overcurrent protection module, the second overcurrent protection module is respectively connected to the base of the third transistor and the fourth transistor, the collector of the third transistor is connected to the voltage input, the collector of the fourth transistor is grounded, the emitters of the third transistor and the fourth transistor are connected to the other end of the seventh resistor and the eighth resistor, and one end of the seventh resistor and the eighth resistor is used as a negative phase output.

[0012] Further, the first overcurrent protection module and the second overcurrent protection module each include two overcurrent protection amplifiers, the inverting input terminal of each overcurrent protection amplifier is respectively connected to one end of a ninth resistor, an eleventh resistor and a twelfth resistor, the non-inverting input terminal of the overcurrent protection amplifier is respectively connected to one end of a tenth resistor, a thirteenth resistor and a fourteenth resistor, and the other end of the twelfth resistor and the thirteenth resistor is connected to a reference voltage.

[0013] Further, the other ends of the two ninth resistors in the first overcurrent protection module are connected to the output end of the first operational amplifier, the other ends of the two tenth resistors in the first overcurrent protection module are respectively connected to the emitters of the first triode and the second triode, the other ends of the two ninth resistors in the second overcurrent protection module are connected to the output end of the second operational amplifier, and the other ends of the two tenth resistors in the second overcurrent protection module are respectively connected to the emitters of the third triode and the fourth triode;

[0014] The output ends of the two overcurrent protection amplifiers in the first overcurrent protection module are connected to the base of the first transistor and the second transistor respectively, and the output ends of the two overcurrent protection amplifiers in the second overcurrent protection module are connected to the base of the third transistor and the fourth transistor respectively.

[0015] Further, the sine-cosine signal buffer circuit includes a first switch tube and a second switch tube, the drains of the first switch tube and the second switch tube are connected, the sine-cosine signal output of the rotary transformer is connected to the drain of the first switch tube, the negative pole of the rotary transformer is connected to the drain of the second switch tube, the source of the first switch tube is connected to one end of a fifteenth resistor, the other end of the fifteenth resistor is connected to the inverting input end of the third operational amplifier, the inverting input end of the third operational amplifier is connected to one end of a twenty-second resistor, the other end of the twenty-second resistor is connected to one end of a twenty-third resistor, the other end of the twenty-third resistor is connected to the AN1 pin of the microcontroller, the source of the second switch tube is connected to one end of a sixteenth resistor, the other end of the sixteenth resistor is connected to the non-inverting input end of the third operational amplifier, the other end of the sixteenth resistor is also connected to one end of a seventeenth resistor, and the other end of the seventeenth resistor and the AN2 pin of the microcontroller are connected to the power supply voltage together.

[0016] Furthermore, the sine-cosine signal buffer circuit also includes a third switch tube and a fourth switch tube, the negative cosine signal output of the rotary transformer is connected to the drain of the third switch tube and the fourth switch tube, the drains of the third switch tube and the fourth switch tube are both connected to the drains of the first switch tube and the second switch tube, the source of the third switch tube is respectively connected to one end of the twentieth resistor, the twenty-first resistor and the twenty-fifth resistor, the source of the fourth switch tube is connected to the AN2 pin of the microcontroller through the twenty-fourth resistor, the other end of the twentieth resistor and one end of the nineteenth resistor are commonly connected to the negative phase output of the excitation amplifier module, the other end of the nineteenth resistor is connected to one end of the eighteenth resistor, the other ends of the eighteenth resistor and the twenty-first resistor are connected to the power supply voltage, and the other end of the twenty-fifth resistor is respectively connected to the AN1 and AN2 pins of the microcontroller.

[0017] The advantages of the present invention are: by utilizing signal modulation and external discrete component circuits, the generation of resolver excitation signals is realized in a low-cost manner, thereby reducing system costs; the compatible sine-cosine signal buffer circuit design can support the requirements of isolated and non-isolated resolvers for matching circuits; the excitation signal amplification circuit has a complete overcurrent protection function and can achieve active shutdown, and the solution is simple and reliable, and is easy to implement and promote in mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is the overall structural diagram of the present invention;

[0019] Figure 2 It is a structural diagram of the excitation signal generation and excitation amplification circuit in the present invention;

[0020] Figure 3 This is the circuit topology diagram of the overcurrent protection module;

[0021] Figure 4 This is the circuit structure diagram of the sine and cosine signal buffer circuit.

[0022] Reference numerals:

[0023] 1Excitation signal generation module 2Excitation amplifier module 3Revolving transformer

[0024] 4 Sincosine signal buffer circuit 5 Microcontroller

[0025] R1~25 1st~25th resistor C1~4 1st~4th capacitor Q1~4 1st~4th transistor

[0026] U1 is the first operational amplifier. U3 is the second operational amplifier.

[0027] U2 first overcurrent protection module U4 second overcurrent protection module

[0028] U5 overcurrent protection amplifier U6 third operational amplifier

[0029] S1~4 are the first to fourth switch tubes. DETAILED DESCRIPTION

[0030] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. 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.

[0031] The present invention discloses a compatible rotary transformer matching circuit suitable for an xEV inverter, characterized in that: Figure 1As shown, it includes an excitation signal generating module 1, an excitation amplifying module 2, a rotary transformer 3, a sine-cosine signal buffer circuit 4 and a microcontroller 5, wherein the output end of the excitation signal generating module 1 is connected to the input end of the excitation amplifying module 2, the output end of the excitation amplifying module 2 is connected to the input end of the rotary transformer 3, the output end of the rotary transformer 3 is connected to the input end of the sine-cosine signal buffer circuit 4, and the output end of the sine-cosine signal buffer circuit 4 is connected to the input end of the microcontroller 5.

[0032] The microcontroller 5 modulates two sinusoidal signals with the same amplitude and DC bias and a phase difference of 180°, and outputs a PWM wave. The frequency of the sinusoidal signal is the excitation frequency output to the resolver, which is configured by the MCU. The two PWM waves are filtered through an external RC circuit. The filtered waveforms are two complementary sinusoidal signals with DC bias. The AC component in the signal is coupled to the input of the op amp through a capacitor.

[0033] like Figure 2 As shown, the excitation signal generating module 1 includes a first resistor R1, one end of which inputs a positive phase waveform, the other end of which is respectively connected to one end of a first capacitor C1 and a second capacitor C2, and the other end of the second capacitor C2 is grounded.

[0034] The excitation signal generating module 1 comprises a fifth resistor R5, one end of which inputs an inverted waveform, the other end of which is respectively connected to one end of the third capacitor C3 and one end of the fourth capacitor C4, and the other end of the fourth capacitor C4 is grounded.

[0035] The excitation amplification module 2 includes a first operational amplifier U1, the other end of the first capacitor C1 is connected to the inverting input end of the first operational amplifier U1, the inverting input end of the first operational amplifier U1 is connected to one end of the second resistor R2, the other end of the second resistor R2 is connected to one end of the third resistor R3 and the fourth resistor R4, the other ends of the third resistor R3 and the fourth resistor R4 and the output end of the first operational amplifier U1 are all connected to the first overcurrent protection module U2, the first overcurrent protection module U2 is respectively connected to the base of the first transistor Q1 and the second transistor Q2, the collector of the first transistor Q1 is connected to the voltage input, the collector of the second transistor Q2 is grounded, the emitters of the first transistor Q1 and the second transistor Q2 are connected to the other ends of the third resistor R3 and the fourth resistor R4, and one end of the third resistor R3 and the fourth resistor R4 is used as the positive phase output R+.

[0036] The excitation amplification module 2 also includes a second operational amplifier U3, the other end of the third capacitor C3 is connected to the inverting input end of the second operational amplifier U3, the inverting input end of the second operational amplifier U3 is connected to one end of the sixth resistor R6, the other end of the sixth resistor R6 is connected to one end of the seventh resistor R7 and the eighth resistor R8, the other ends of the seventh resistor R7 and the eighth resistor R8 and the output end of the second operational amplifier U3 are all connected to the second overcurrent protection module U4, the second overcurrent protection module U4 is respectively connected to the base of the third transistor Q3 and the fourth transistor Q4, the collector of the third transistor Q3 is connected to the voltage input, the collector of the fourth transistor Q4 is grounded, the emitters of the third transistor Q3 and the fourth transistor Q4 are connected to the other ends of the seventh resistor R7 and the eighth resistor R8, and one end of the seventh resistor R7 and the eighth resistor R8 is used as the negative phase output R-.

[0037] The non-inverting input terminals of the first operational amplifier U1 and the second operational amplifier U3 are both connected to the reference voltage Vref. According to the "virtual short" principle of the operational amplifier, the DC component of the voltage input to the resolver R+ and R- by the excitation signal amplification circuit is also Vref. When the excitation input is a sinusoidal signal, the signal at the R+ terminal is also sinusoidal and is superimposed with the DC value Vref. By adjusting the ratio of the resistance of the RC filter circuit and the negative feedback resistance, the peak-to-peak value of the sinusoidal signal at the R+ and R- terminals is changed. The output signal of the operational amplifier drives the high-power transistors at the output terminal, namely the first to fourth transistors Q4Q1~4, through the overcurrent protection circuit module, and the push-pull structure formed by the above four transistors is used to achieve power amplification.

[0038] When the excitation R+ and R- are short-circuited to GND or power supply for various reasons, or the two phases are short-circuited, the excitation current will be too large. If the excitation output is not turned off in time, there will be a risk of burning out the device. In the excitation amplifier circuit module 2, an overcurrent comparison circuit is set, and its topology is as follows: Figure 3 As shown, the first overcurrent protection module U2 and the second overcurrent protection module U4 each include two overcurrent protection amplifiers U5, the inverting input end of each overcurrent protection amplifier U5 is respectively connected to one end of a ninth resistor R9, an eleventh resistor R11 and a twelfth resistor R12, the non-inverting input end of the overcurrent protection amplifier U5 is respectively connected to one end of a tenth resistor R10, a thirteenth resistor R13 and a fourteenth resistor R14, and the other ends of the twelfth resistor R12 and the thirteenth resistor R13 are connected to the reference voltage Vref.

[0039] like Figure 3As shown, the other ends of the two ninth resistors R9 in the first overcurrent protection module U2 are connected to the output end of the first operational amplifier U1, the other ends of the two tenth resistors R10 in the first overcurrent protection module U2 are respectively connected to the emitters of the first triode Q1 and the second triode, the other ends of the two ninth resistors R9 in the second overcurrent protection module U4 are connected to the output end of the second operational amplifier U3, and the other ends of the two tenth resistors R10 in the second overcurrent protection module U4 are respectively connected to the emitters of the third triode Q3 and the fourth triode Q4;

[0040] The output ends of the two overcurrent protection amplifiers U5 in the first overcurrent protection module U2 are connected to the base of the first transistor Q1 and the second transistor respectively, and the output ends of the two overcurrent protection amplifiers U5 in the second overcurrent protection module U4 are connected to the base of the third transistor Q3 and the fourth transistor Q4 respectively.

[0041] The two overcurrent protection modules U1 and U2 determine the size of the excitation current by detecting the voltage drop on the resistor at the output end of the excitation signal generating module 1. When the voltage drop is greater than a certain threshold Uth, the overcurrent comparator will output a low level, thereby triggering the protection circuit to operate. The overcurrent protection module disconnects the corresponding transistor to achieve the purpose of protection.

[0042] In addition, the microcontroller 5 can also output high and low levels to the overcurrent protection module through the IO port to achieve active shutdown of the resolver excitation.

[0043] like Figure 4 As shown, the sine-cosine signal buffer circuit 4 includes a first switch tube S1 and a second switch tube S2, the drains of the first switch tube S1 and the second switch tube S2 are connected, the sine-cosine signal output Sin+ of the rotary transformer 3 is connected to the drain of the first switch tube S1, the negative electrode of the rotary transformer 3 is connected to the drain of the second switch tube S2, the source of the first switch tube S1 is connected to one end of the fifteenth resistor R15, the other end of the fifteenth resistor R15 is connected to the inverting input end of the third operational amplifier U6, the inverting input end of the third operational amplifier U6 is connected to the twenty-second One end of the resistor R22 is connected, the other end of the twenty-second resistor R22 is connected to one end of the twenty-third resistor R23, the other end of the twenty-third resistor R23 is connected to the AN1 pin of the microcontroller 5, the source of the second switch tube S2 is connected to one end of the sixteenth resistor R16, the other end of the sixteenth resistor R16 is connected to the non-inverting input terminal of the third operational amplifier U6, the other end of the sixteenth resistor R16 is also connected to one end of the seventeenth resistor R17, and the other end of the seventeenth resistor R17 and the AN2 pin of the microcontroller 5 are connected to the power supply voltage together.

[0044] The sine-cosine signal buffer circuit 4 also includes a third switch tube S3 and a fourth switch tube S4. The negative cosine signal output Sin- of the rotary transformer 3 is connected to the drain of the third switch tube S3 and the fourth switch tube S4. The drains of the third switch tube S3 and the fourth switch tube S4 are connected to the drains of the first switch tube S1 and the second switch tube S2. The source of the third switch tube S3 is respectively connected to one end of the twentieth resistor R20, the twenty-first resistor R21 and the twenty-fifth resistor R25. The source of the fourth switch tube S4 is connected to the AN2 pin of the microcontroller 5 through the twenty-fourth resistor R24. The other end of the twentieth resistor R20 and one end of the nineteenth resistor R19 are commonly connected to the negative phase output R- of the excitation amplifier module 2. The other end of the nineteenth resistor R19 is connected to one end of the eighteenth resistor R18. The other ends of the eighteenth resistor R18 and the twenty-first resistor R21 are connected to the power supply voltage VDD. The other end of the twenty-fifth resistor R25 is respectively connected to the AN1 and AN2 pins of the microcontroller 5.

[0045] In the structure of the sine-cosine signal buffer circuit 4 compatible with isolated and non-isolated resolvers, the switches S1-S4 are controlled by a microcontroller 5 to select the buffer circuit.

[0046] When the resolver used in the drive system is an isolated resolver, the microcontroller 5 controls the first switch tube S1 and the second switch tube S2 to close, connect the isolated resolver buffer circuit, and disconnect the third switch tube S3 and the fourth switch tube S4 to disconnect the non-isolated resolver buffer circuit. At this time, the sine and cosine signals returned by the resolver are biased and proportionally amplified and input to the AD port of the microcontroller 5;

[0047] When the resolver used in the driving system is a non-isolated resolver, the microcontroller 5 controls the first switch tube S1 and the second switch tube S2 to be disconnected, disconnects the isolated resolver buffer circuit, and simultaneously closes the third switch tube S3 and the fourth switch tube S4 to connect the non-isolated resolver buffer circuit. At this time, the sine and cosine signals returned by the resolver are directly input into the AD port of the microcontroller 5 after being clamped.

[0048] In specific implementation, the microcontroller 5 reads the voltage values ​​of the sine and cosine signals input from the AD port, namely the AN1 and AN2 pins, performs differential operation, obtains the amplitude and phase relationship of the sine and cosine signals, and further calculates the current rotor position and speed information.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A compatible rotary transformer matching circuit suitable for xEV inverter, characterized in that: It includes an excitation signal generating module, an excitation amplifying module, a rotary transformer, a sine-cosine signal buffer circuit and a microcontroller, wherein the output end of the excitation signal generating module is connected to the input end of the excitation amplifying module, the output end of the excitation amplifying module is connected to the input end of the rotary transformer, the output end of the rotary transformer is connected to the input end of the sine-cosine signal buffer circuit, and the output end of the sine-cosine signal buffer circuit is connected to the input end of the microcontroller; The excitation signal generating module comprises a first resistor, one end of which inputs a positive phase waveform, the other end of which is respectively connected to one end of a first capacitor and a second capacitor, and the other end of the second capacitor is grounded; The excitation signal generating module comprises a fifth resistor, one end of which is input with an inverted waveform, the other end of which is respectively connected with one end of the third capacitor and one end of the fourth capacitor, and the other end of the fourth capacitor is grounded; The excitation amplification module includes a first operational amplifier, the other end of the first capacitor is connected to the inverting input end of the first operational amplifier, the inverting input end of the first operational amplifier is connected to one end of the second resistor, the other end of the second resistor is connected to one end of the third resistor and the fourth resistor, the other ends of the third resistor and the fourth resistor and the output end of the first operational amplifier are all connected to a first overcurrent protection module, the first overcurrent protection module is respectively connected to the base of the first triode and the second triode, the collector of the first triode is connected to the voltage input, the collector of the second triode is grounded, the emitters of the first triode and the second triode are connected to the other ends of the third resistor and the fourth resistor, and one end of the third resistor and the fourth resistor is used as a positive phase output; The excitation amplification module also includes a second operational amplifier, the other end of the third capacitor is connected to the inverting input end of the second operational amplifier, the inverting input end of the second operational amplifier is connected to one end of the sixth resistor, the other end of the sixth resistor is connected to one end of the seventh resistor and the eighth resistor, the other ends of the seventh resistor and the eighth resistor and the output end of the second operational amplifier are all connected to the second overcurrent protection module, the second overcurrent protection module is respectively connected to the base of the third triode and the fourth triode, the collector of the third triode is connected to the voltage input, the collector of the fourth triode is grounded, the emitters of the third triode and the fourth triode are connected to the other ends of the seventh resistor and the eighth resistor, and one end of the seventh resistor and the eighth resistor is used as a negative phase output; The microcontroller outputs high and low levels to the first overcurrent protection module and the second overcurrent protection module through the IO port to achieve active shutdown of the resolver excitation.

2. The compatible rotary transformer matching circuit suitable for xEV inverter according to claim 1, characterized in that: The first overcurrent protection module and the second overcurrent protection module each include two overcurrent protection amplifiers, the inverting input terminal of each overcurrent protection amplifier is respectively connected to one end of a ninth resistor, an eleventh resistor and a twelfth resistor, the non-inverting input terminal of the overcurrent protection amplifier is respectively connected to one end of a tenth resistor, a thirteenth resistor and a fourteenth resistor, and the other ends of the twelfth resistor and the thirteenth resistor are connected to a reference voltage.

3. The compatible rotary transformer matching circuit suitable for xEV inverter according to claim 2, characterized in that: The other ends of the two ninth resistors in the first overcurrent protection module are connected to the output end of the first operational amplifier, the other ends of the two tenth resistors in the first overcurrent protection module are respectively connected to the emitters of the first triode and the second triode, the other ends of the two ninth resistors in the second overcurrent protection module are connected to the output end of the second operational amplifier, and the other ends of the two tenth resistors in the second overcurrent protection module are respectively connected to the emitters of the third triode and the fourth triode; The output ends of the two overcurrent protection amplifiers in the first overcurrent protection module are connected to the base of the first transistor and the second transistor respectively, and the output ends of the two overcurrent protection amplifiers in the second overcurrent protection module are connected to the base of the third transistor and the fourth transistor respectively.

4. The compatible rotary transformer matching circuit suitable for xEV inverter according to claim 3, characterized in that: The sine-cosine signal buffer circuit includes a first switch tube and a second switch tube, the drains of the first switch tube and the second switch tube are connected, the sine-cosine signal output of the rotary transformer is connected to the drain of the first switch tube, the negative electrode of the rotary transformer is connected to the drain of the second switch tube, the source of the first switch tube is connected to one end of a fifteenth resistor, the other end of the fifteenth resistor is connected to the inverting input end of a third operational amplifier, the inverting input end of the third operational amplifier is connected to one end of a twenty-second resistor, the other end of the twenty-second resistor is connected to one end of a twenty-third resistor, the other end of the twenty-third resistor is connected to the AN1 pin of the microcontroller, the source of the second switch tube is connected to one end of a sixteenth resistor, the other end of the sixteenth resistor is connected to the non-inverting input end of the third operational amplifier, the other end of the sixteenth resistor is also connected to one end of a seventeenth resistor, and the other end of the seventeenth resistor and the AN2 pin of the microcontroller are connected to a power supply voltage.

5. The compatible rotary transformer matching circuit suitable for xEV inverter according to claim 4, characterized in that: The sine-cosine signal buffer circuit also includes a third switch tube and a fourth switch tube. The negative cosine signal output of the rotary transformer is connected to the drain of the third switch tube and the fourth switch tube. The drains of the third switch tube and the fourth switch tube are both connected to the drains of the first switch tube and the second switch tube. The source of the third switch tube is respectively connected to one end of the twentieth resistor, the twenty-first resistor and the twenty-fifth resistor. The source of the fourth switch tube is connected to the AN2 pin of the microcontroller through the twenty-fourth resistor. The other end of the twentieth resistor and one end of the nineteenth resistor are commonly connected to the negative phase output of the excitation amplifier module. The other end of the nineteenth resistor is connected to one end of the eighteenth resistor. The other ends of the eighteenth resistor and the twenty-first resistor are connected to the power supply voltage. The other end of the twenty-fifth resistor is respectively connected to the AN1 and AN2 pins of the microcontroller.

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