High-precision anti-interference rotary transformer decoding circuit

Abstract

The utility model discloses a high-precision anti-interference rotary transformer decoding circuit. The decoding circuit is composed of a second-order Butterworth filter excitation circuit and a third-order Butterworth filter receiving circuit. The excitation circuit completes the function of a low-pass filter by selecting an adaptive gain and wide-product operational amplifier and calculating the resistance gain and the common-mode voltage of the amplifier, and meets the output requirement of an excitation signal at the same time. And the receiving circuit configures a corresponding input resistor and an operational amplifier by calculating a single-side on-state amplification factor and a cut-off frequency of the circuit so as to adapt to the use requirement of a rotary transformer decoding chip and complete low-noise receiving of a rotary transformer signal. The circuit is simple in structure, high in precision, strong in decoding capability, strong in inhibition capability for interference signals, and high in electromagnetic compatibility and reliability.

Description

Technical Field

[0001] The utility model relates to the technical field of resolvers, in particular to a resolver decoding circuit with high precision and anti-interference performance. Background Technique

[0002] A resolver is an inductive micromotor whose output voltage maintains a certain functional relationship with the rotor angle. In essence, it is a transformer. It is a displacement sensor that converts angular displacement into an electrical signal and is also a resolver element capable of coordinate conversion and function operation. There is relative motion between the primary side and the secondary side of the resolver. As the relative angle between the two changes, the magnetic circuit and magnetic reluctance change. Since the inductance value of the coil is different at different positions, at a fixed frequency, it shows different impedance ratios. Therefore, its impedance is the impedance at the electrical zero position and a specific frequency.

[0003] Resolvers are mainly used for voltage conversion in the power grid, measurement of signals such as position, angle, and speed, control and regulation of the speed and voltage of motors, and realization of high-precision speed control and switching of the running direction of motors. Currently, the AD2S1210 decoding chip of AD company is commonly used in the market to decode and calculate resolver signals. However, due to the gain ratio and frequency problems of AD8397 and AD8692 in the common recommended circuit of this chip, and the system fault detection and programmable fault detection functions of AD2S1210, in the face of a relatively harsh working environment, problems such as EMC electromagnetic interference and false alarms will occur.

[0004] The Butterworth filter is an active filter with a relatively flat frequency response in the passband. Using Butterworth filter technology, all types of filters can be designed, including high-pass, low-pass, band-pass, etc. When designing, the maximum flatness of the passband response, the slow transition from the passband to the stopband, and the ability to completely pass the signal should be mainly considered. Content of the Utility Model

[0005] The purpose of the utility model is to provide a resolver decoding circuit with a simple circuit structure, high precision, strong decoding ability, strong suppression ability for interference signals, and high electromagnetic compatibility and reliability.

[0006] The purpose of the utility model is achieved through the following technical scheme: a resolver decoding circuit with high precision and anti-interference performance, including a second-order Butterworth filter excitation circuit and a third-order active Butterworth filter receiving circuit;

[0007] The second-order Butterworth filter excitation circuit is specifically as follows: The excitation signal EXC+ is input to the inverting input terminal of operational amplifier U8A through resistor R234, and after being transformed by the conditioning circuit, it is output from the output terminal of operational amplifier U8A. Then, it is processed by a first-order filter circuit composed of resistor R192 and capacitor C248, and finally input to the non-inverting input terminal of operational amplifier U12A and output from the output terminal of operational amplifier U12A;

[0008] The excitation signal EXC- is input to the inverting input terminal of operational amplifier U8B through resistor R253, and after being transformed by the conditioning circuit, it is output from the output terminal of operational amplifier U8B. Then, it is processed by a first-order filter circuit composed of resistor R193 and capacitor C249, and finally input to the non-inverting input terminal of operational amplifier U12B and output from the output terminal of operational amplifier U12B.

[0009] Further, in the second-order Butterworth filter excitation circuit:

[0010] The excitation signal EXC+ is connected to the first end of resistor R234, the second end of resistor R234 is connected to the inverting input terminal of operational amplifier U8A, the inverting input terminal of operational amplifier U8A is respectively connected to the first end of resistor R254 and the first end of capacitor C246, the output terminal of operational amplifier U8A is respectively connected to the second end of resistor R254 and the second end of capacitor C246, and the output terminal of operational amplifier U8A is also connected to the first end of resistor R192; The 8.8V voltage source is connected to the first end of resistor R233, the second end of resistor R233 is connected to the non-inverting input terminal of operational amplifier U8A, and the non-inverting input terminal of operational amplifier U8A is connected to M15 ground through resistor R232; The negative and positive power supply terminals of operational amplifier U8A are respectively connected to the negative and positive power supply terminals of P15; A first-order active Butterworth filter is formed; The cut-off frequency of the first-order active Butterworth filter where R 234 is the resistance value of resistor R234, and C 246 is the capacitance value of capacitor C246;

[0011] The first-order passive low-pass filter is composed of resistor R192 and capacitor C248. The second end of resistor R192 is connected to the first end of capacitor C248, the second end of capacitor C248 is connected to M15 ground, the second end of resistor R192 is connected to the non-inverting input terminal of operational amplifier U12A, the positive and negative power supply terminals of operational amplifier U12A are respectively connected to the positive and negative power supplies of P15, the inverting input terminal of operational amplifier U12A is connected to the output terminal, and the output terminal of operational amplifier U12A is respectively connected to the first ends of resistor R194 and resistor R195, and the second ends of resistor R194 and resistor R195 are connected to the resolver output signal;

[0012] The first - order active Butterworth filter and the first - order passive low - pass filter are cascaded to form a second - order Butterworth filter excitation circuit.

[0013] Further, in the second - order Butterworth filter excitation circuit:

[0014] The excitation signal EXC− is connected to the first end of resistor R253. The second end of resistor R253 is connected to the inverting input terminal of operational amplifier U8B. The inverting input terminal of operational amplifier U8B is respectively connected to the first end of resistor R255 and the first end of capacitor C247. The output terminal of operational amplifier U8B is respectively connected to the second end of resistor R255 and the second end of capacitor C247. The output terminal of operational amplifier U8B is also connected to the first end of resistor R193. The 8.8V voltage source is connected to the first end of resistor R252. The second end of resistor R252 is connected to the non - inverting input terminal of operational amplifier U8B. The non - inverting input terminal of operational amplifier U8B is connected to M15 ground through resistor R235. The negative and positive power supply terminals of operational amplifier U8B are respectively connected to the negative and positive power supply terminals of P15, forming a first - order active Butterworth filter.

[0015] The first - order passive low - pass filter is composed of resistor R193 and capacitor C249. The second end of resistor R193 is connected to the first end of capacitor C249. The second end of capacitor C249 is connected to M15 ground. The second end of resistor R193 is connected to the non - inverting input terminal of operational amplifier U12B. The positive and negative power supply terminals of operational amplifier U12B are respectively connected to the positive and negative power supply terminals of P15. The inverting input terminal of operational amplifier U12B is connected to the output terminal, and the output terminal of operational amplifier U12B is respectively connected to the first ends of resistor R196 and resistor R197. The second ends of resistor R196 and resistor R197 are connected to the resolver output signal.

[0016] The first - order active Butterworth filter and the first - order passive low - pass filter are cascaded to form a second - order Butterworth filter excitation circuit.

[0017] Further, in the third - order active Butterworth filter receiving circuit:

[0018] The SIN + resolver signal of the third - order Butterworth filter receiving circuit is connected to the first ends of resistor R180 and resistor R183. The second ends of resistor R180 and resistor R183 are both connected to the first end of capacitor C115, the first end of resistor R181, and the inverting input terminal of amplifier U7B. The non - inverting input terminal of amplifier U7B is connected to the reference source VERF2.5V. The second ends of capacitor C115 and resistor R181 are both connected to the output terminal of amplifier U7B and the first end of resistor R184, forming a first - order active Butterworth filter.

[0019] The second end of the resistor R184 is connected to the first end of the capacitor C117, forming a first-order passive filter Butterworth filter;

[0020] The second end of the resistor R184 is respectively connected to the first end of the resistor R179 and the first end of the resistor R185. The second end of the capacitor C117 is connected to M ground. The second end of the resistor R185 is respectively connected to the inverting input terminal of the amplifier U8B and the first end of the capacitor C116. The non-inverting input terminal of the amplifier U8B is connected to the reference source VERF2.5V. The second end of the capacitor C116 and the second end of the resistor R179 are both connected to the output terminal of the amplifier U8B. The output terminal of the amplifier U8B is connected to AD2S1210, forming a first-order active Butterworth filter;

[0021] Two groups of first-order active Butterworth filters and first-order passive filter Butterworth filters are cascaded to form a third-order Butterworth filter.

[0022] Further, in the receiving circuit of the third-order active Butterworth filter:

[0023] A capacitor C123 is provided between the SIN - resolver signal and the SIN + resolver signal of the receiving circuit of the third-order Butterworth filter. The SIN - resolver signal is connected to the first end of the resistor R189 and the first end of the resistor R191. The second end of the resistor R189 and the second end of the resistor R191 are both connected to the first end of the capacitor C125, the first end of the resistor R190, and the inverting input terminal of the amplifier U7A; the non-inverting input terminal of the amplifier U7A is connected to the reference source VERF2.5V. The second end of the capacitor C125 and the second end of the resistor R190 are both connected to the output terminal of the amplifier U7A and the first end of the resistor R192, forming a first-order active Butterworth filter;

[0024] The second end of the resistor R192 is connected to the first end of the capacitor C130, forming a first-order passive filter Butterworth filter;

[0025] The second end of the resistor R192 is respectively connected to the first end of the resistor R188 and the first end of the resistor R193. The second end of the capacitor C130 is connected to M ground. The second end of the resistor R193 is respectively connected to the inverting input terminal of the amplifier U8A and the first end of the capacitor C129. The non-inverting input terminal of the amplifier U8A is connected to the reference source VERF2.5V. The second end of the capacitor C129 and the second end of the resistor R188 are both connected to the output terminal of the amplifier U8A. The output terminal of the amplifier U8A is connected to AD2S1210, forming a first-order active Butterworth filter;

[0026] Two sets of first-order active Butterworth filters and a first-order passive Butterworth filter are cascaded to form a third-order Butterworth filter.

[0027] Compared with the prior art, the remarkable advantages of the present invention are as follows:

[0028] (1) Configure the corresponding circuit parameters according to the parameters such as the phase-locked range and excitation frequency of the AD2S1210 decoding chip. The peripheral circuit structure is simple and the accuracy is high;

[0029] (2) It can realize 10 / 12 / 14 / 16-bit resolution decoding. At the same time, the ability to suppress interference signals is stronger, improving the electromagnetic compatibility performance and reliability, and meeting the special requirements of the equipment for the servo driver. Description of the Drawings

[0030] Figure 1 is the schematic diagram of the excitation circuit of the second-order active Butterworth filter of the present invention.

[0031] Figure 2 is the structural schematic diagram of the receiving circuit of the third-order Butterworth filter of the present invention. Detailed Embodiment

[0032] Combined with Figures 1 to 2 , the present invention provides a resolver decoding circuit with high precision and anti-interference, including a second-order Butterworth filter excitation circuit and a third-order active Butterworth filter receiving circuit;

[0033] The second-order Butterworth filter excitation circuit performs filtering through a low-pass filter to reduce signal noise, and then configures corresponding resistors for signal amplification according to the excitation frequency and the phase-locked range of the resolver decoding chip;

[0034] The third-order active Butterworth filter receiving circuit configures corresponding resistors for signal filtering and transmission by calculating the impedance matching and cut-off frequency of the differential signals in the circuit; the matching impedance adjusts the proportional relationship between the resistors according to the ratio relationship between the output and the input.

[0035] As a specific example, in the second-order Butterworth filter excitation circuit:

[0036] The excitation signal EXC+ is input to the inverting input terminal of the operational amplifier U8A through the resistor R234, is transformed by the conditioning circuit and output from the output terminal of the operational amplifier U8A, and then is processed by the first-order filter circuit composed of the resistor R192 and the capacitor C248, and finally is input to the non-inverting input terminal of the operational amplifier U12A and output from the output terminal of the operational amplifier U12A;

[0037] The excitation signal EXC- is input to the inverting input terminal of the operational amplifier U8B through the resistor R253, and after being transformed by the conditioning circuit, it is output from the output terminal of the operational amplifier U8B. Then, it is processed by the first-order filter circuit composed of the resistor R193 and the capacitor C249, and finally input to the non-inverting input terminal of the operational amplifier U12B and output from the output terminal of the operational amplifier U12B.

[0038] As a specific example, in the second-order Butterworth filter excitation circuit:

[0039] The excitation signal EXC+ is connected to the first end of the resistor R234, the second end of the resistor R234 is connected to the inverting input terminal of the operational amplifier U8A, the inverting input terminal of the operational amplifier U8A is respectively connected to the first end of the resistor R254 and the first end of the capacitor C246, the output terminal of the operational amplifier U8A is respectively connected to the second end of the resistor R254 and the second end of the capacitor C246, and the output terminal of the operational amplifier U8A is also connected to the first end of the resistor R192; The 8.8V voltage source is connected to the first end of the resistor R233, the second end of the resistor R233 is connected to the non-inverting input terminal of the operational amplifier U8A, and the non-inverting input terminal of the operational amplifier U8A is connected to the M15 ground through the resistor R232; The negative and positive power supplies of the operational amplifier U8A are respectively connected to the negative and positive power supplies of P15; A first-order active Butterworth filter is formed; where P15 is the 15V positive power supply required for the operational amplifier U8, and M15 is the ground of the negative power supply required for the operational amplifier U8A; The cut-off frequency of the first-order active Butterworth filter where R 234 is the resistance value of the resistor R234, C 246 is the capacitance value of the capacitor C246;

[0040] The first-order passive low-pass filter is composed of the resistor R192 and the capacitor C248. The second end of the resistor R192 is connected to the first end of the capacitor C248, the second end of the capacitor C248 is connected to the M15 ground, the second end of the resistor R192 is connected to the non-inverting input terminal of the operational amplifier U12A, the positive and negative power supplies of the operational amplifier U12A are respectively connected to the positive and negative power supplies of the P15 power supply, the inverting input terminal of the operational amplifier U12A is connected to the output terminal, and the output terminal of the operational amplifier U12A is respectively connected to the first ends of the resistors R194 and R195, and the second ends of the resistors R194 and R195 are connected to the resolver output signal;

[0041] The first-order active Butterworth filter and the first-order passive low-pass filter are connected in cascade to form a second-order Butterworth filter excitation circuit.

[0042] As a specific example, in the second-order Butterworth filter excitation circuit:

[0043] The excitation signal EXC is connected to the first terminal of resistor R253. The second terminal of resistor R253 is connected to the inverting input terminal of operational amplifier U8B. The inverting input terminal of operational amplifier U8B is respectively connected to the first terminal of resistor R255 and the first terminal of capacitor C247. The output terminal of operational amplifier U8B is respectively connected to the second terminal of resistor R255 and the second terminal of capacitor C247. The output terminal of operational amplifier U8B is also connected to the first terminal of resistor R193. The 8.8V voltage source is connected to the first terminal of resistor R252. The second terminal of resistor R252 is connected to the non-inverting input terminal of operational amplifier U8B. The non-inverting input terminal of operational amplifier U8B is connected to M15 ground through resistor R235. The negative and positive power supply terminals of operational amplifier U8B are respectively connected to the negative and positive power supply terminals of P15. It forms a first-order active Butterworth filter.

[0044] The first-order passive low-pass filter is composed of resistor R193 and capacitor C249. The second terminal of resistor R193 is connected to the first terminal of capacitor C249. The second terminal of capacitor C249 is connected to M15 ground. The second terminal of resistor R193 is connected to the non-inverting input terminal of operational amplifier U12B. The positive and negative power supply terminals of operational amplifier U12B are respectively connected to the positive and negative power supply terminals of P15. The inverting input terminal of operational amplifier U12B is connected to the output terminal. And the output terminal of operational amplifier U12B is respectively connected to the first terminals of resistor R196 and resistor R197. The second terminals of resistor R196 and resistor R197 are connected to the resolver output signal.

[0045] The first-order active Butterworth filter and the first-order passive low-pass filter are cascaded to form a second-order Butterworth filter excitation circuit.

[0046] As a specific example, in the third-order active Butterworth filter receiving circuit:

[0047] The SIN+ resolver signal of the third-order Butterworth filter receiving circuit is connected to the first terminals of resistor R180 and resistor R183. The second terminals of resistor R180 and resistor R183 are both connected to the first terminal of capacitor C115, the first terminal of resistor R181, and the inverting input terminal of amplifier U7B. The non-inverting input terminal of amplifier U7B is connected to the reference source VERF2.5V. The second terminals of capacitor C115 and resistor R181 are both connected to the output terminal of amplifier U7B and the first terminal of resistor R184, forming a first-order active Butterworth filter.

[0048] The second terminal of resistor R184 is connected to the first terminal of capacitor C117, forming a first-order passive filter Butterworth filter.

[0049] The second end of the resistor R184 is respectively connected to the first end of the resistor R179 and the first end of the resistor R185. The second end of the capacitor C117 is connected to M ground. The second end of the resistor R185 is respectively connected to the inverting input terminal of the amplifier U8B and the first end of the capacitor C116. The non-inverting input terminal of the amplifier U8B is connected to the reference source VERF2.5V. The second end of the capacitor C116 and the second end of the resistor R179 are both connected to the output terminal of the amplifier U8B. The output terminal of the amplifier U8B is connected to the AD2S1210, forming a first-order active Butterworth filter;

[0050] Two sets of first-order active Butterworth filters and a first-order passive filtering Butterworth filter are cascaded to form a third-order Butterworth filter.

[0051] As a specific example, in the receiving circuit of the third-order active Butterworth filter:

[0052] A capacitor C123 is provided between the SIN - resolver signal and the SIN + resolver signal in the receiving circuit of the third-order Butterworth filter. The SIN - resolver signal is connected to the first end of the resistor R189 and the first end of the resistor R191. The second end of the resistor R189 and the second end of the resistor R191 are both connected to the first end of the capacitor C125, the first end of the resistor R190, and the inverting input terminal of the amplifier U7A; the non-inverting input terminal of the amplifier U7A is connected to the reference source VERF2.5V. The second end of the capacitor C125 and the second end of the resistor R190 are both connected to the output terminal of the amplifier U7A and the first end of the resistor R192, forming a first-order active Butterworth filter;

[0053] The second end of the resistor R192 is connected to the first end of the capacitor C130, forming a first-order passive filtering Butterworth filter;

[0054] The second end of the resistor R192 is respectively connected to the first end of the resistor R188 and the first end of the resistor R193. The second end of the capacitor C130 is connected to M ground. The second end of the resistor R193 is respectively connected to the inverting input terminal of the amplifier U8A and the first end of the capacitor C129. The non-inverting input terminal of the amplifier U8A is connected to the reference source VERF2.5V. The second end of the capacitor C129 and the second end of the resistor R188 are both connected to the output terminal of the amplifier U8A. The output terminal of the amplifier U8A is connected to the AD2S1210, forming a first-order active Butterworth filter;

[0055] Two sets of first-order active Butterworth filters and a first-order passive filtering Butterworth filter are cascaded to form a third-order Butterworth filter.

[0056] The matching impedance adjusts the proportional relationship between the resistor R181 and the resistors R180 and R183 according to the proportional relationship between the output SIN and the input SIN+; the cut-off frequency is determined by the capacitance value of the capacitor and the resistance value of the resistor that make up the filter.

[0057] The following further describes the present utility model in detail with reference to the accompanying drawings and specific embodiments.

[0058] Embodiment

[0059] The novel high-precision anti-interference resolver decoding circuit, the circuit includes a second-order Butterworth filter excitation circuit and a third-order active Butterworth filter receiving circuit. Among them, the second-order active Butterworth filter active filtering excitation circuit includes a first-order active low-pass filter circuit and a first-order passive low-pass filter circuit. The first-order active low-pass filter circuit is composed of an operational amplifier LM2904. The resolver signal EXC of the second-order active low-pass filter circuit is connected to the first end of R234, the second end of R234 is connected to the second end of U8A, the second end of U8A is connected to the first ends of R254 and C246, the first end of U8A is connected to the second ends of R254 and C246, and is connected to the first end of R192. The 8.8V voltage source is connected to the first end of R233, R233 is connected to the third end of U8A, and the fourth end and the eighth end of U8A are respectively connected to the negative and positive poles of the P15 power supply to form active filtering. The voltage gain A of this circuit up =-1, the cut-off frequency of the first-order filter f0 = 1 / (2π×R 254 ×C 264 ), the voltage gain of the 10kHz sine input signal The phase shift of the 10kHz sine input signal

[0060] The first-order passive low-pass filter is composed of R192 and C248. The first end of U8A is connected to the first end of R192, the second end of R192 is connected to the first end of C248, the second end of C248 is connected to the ground of M15, the second end of R192 is connected to the third end of U12A, the eighth end and the fourth end of U12A are respectively connected to the positive and negative poles of the P15 power supply. The first end of U12A is respectively connected to the first ends of R194 and R195, and the second ends of R194 and R195 are connected to the resolver output signal. The voltage gain A of this circuit UP is 1, the cut-off frequency of the first-order filter f0 = 1 / (2π×R 192 ×C 248 ), the voltage gain of the 10kHz sine input signal

[0061] The third-order active Butterworth filter receiving circuit adopts a third-order Butterworth filter. In order to filter out the interference signals received during the long-distance transmission between the resolver and the driver decoding and receiving circuit, its filtering requirements are higher than those of the excitation signal filtering, and its ability to suppress high-frequency interference signals is stronger. For the amplitude-frequency characteristic of the filter, the falling slope after its cut-off frequency should be steep, so a third-order filter circuit is adopted. The SIN+ resolver signal of the circuit is connected to the first ends of R180 and R183. The second ends of R180 and R183 are connected to the first ends of C115, R181, and the sixth end of U7. The fifth end of U7 is connected to the reference source VERF2.5V. The second ends of C115 and R181 are connected to the seventh end of U7 and the first end of R184. The second end of R184 is connected to the first ends of R179, R185, and the first end of C117. The second end of C117 is connected to GND. The second end of R185 is connected to the sixth end of U8 and the first end of C116. The fifth end of U8 is connected to the reference source VERF2.5V. After the second ends of C116 and R179 are connected to the seventh end of U8, it is output to AD2S1210.

[0062] In summary, the novel high-precision anti-interference resolver decoding circuit has a simple control circuit, strong anti-interference ability, high compatibility and reliability, and at the same time has a 100% domestic substitution solution for components.

[0063] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Any person skilled in the art may use the disclosed technical content to make changes or modifications into equivalent embodiments with equivalent changes and apply them to other fields. However, as long as it does not depart from the technical solution content of the present invention, any simple modification, equivalent change, and modification made to the above embodiments based on the technical essence of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A resolver decoding circuit with high precision and anti-interference, characterized in that, It includes a second-order Butterworth filter excitation circuit and a third-order active Butterworth filter receiving circuit; The specific structure of the second-order Butterworth filter excitation circuit is as follows: The excitation signal EXC+ is input to the inverting input terminal of operational amplifier U8A through resistor R234. After being transformed by the conditioning circuit, it is output from the output terminal of operational amplifier U8A, then processed by a first-order filter circuit composed of resistor R192 and capacitor C248, and finally input to the non-inverting input terminal of operational amplifier U12A and output from the output terminal of operational amplifier U12A; The excitation signal EXC- is input to the inverting input terminal of operational amplifier U8B through resistor R253. After being transformed by the conditioning circuit, it is output from the output terminal of operational amplifier U8B, then processed by a first-order filter circuit composed of resistor R193 and capacitor C249, and finally input to the non-inverting input terminal of operational amplifier U12B and output from the output terminal of operational amplifier U12B.

2. The resolver decoding circuit with high precision and anti-interference according to claim 1, characterized in that, In the second-order Butterworth filter excitation circuit: The excitation signal EXC+ is connected to the first terminal of resistor R234. The second terminal of resistor R234 is connected to the inverting input terminal of operational amplifier U8A. The inverting input terminal of operational amplifier U8A is respectively connected to the first terminal of resistor R254 and the first terminal of capacitor C246. The output terminal of operational amplifier U8A is respectively connected to the second terminal of resistor R254 and the second terminal of capacitor C246. The output terminal of operational amplifier U8A is also connected to the first terminal of resistor R192. The 8.8V voltage source is connected to the first terminal of resistor R233. The second terminal of resistor R233 is connected to the non-inverting input terminal of operational amplifier U8A. The non-inverting input terminal of operational amplifier U8A is connected to the M15 ground through resistor R232. The negative and positive power supply terminals of operational amplifier U8A are respectively connected to the negative and positive power supply terminals of P15, forming a first-order active Butterworth filter. The cut-off frequency of the first-order active Butterworth filter where R 234 is the resistance value of resistor R234, and C 246 is the capacitance value of capacitor C246; The first-order passive low-pass filter is composed of resistor R192 and capacitor C248. The second end of resistor R192 is connected to the first end of capacitor C248. The second end of capacitor C248 is connected to M15 ground. The second end of resistor R192 is connected to the non-inverting input terminal of operational amplifier U12A. The positive and negative power supply terminals of operational amplifier U12A are respectively connected to the positive and negative power supply terminals of P15 power supply. The inverting input terminal of operational amplifier U12A is connected to its output terminal, and the output terminal of operational amplifier U12A is respectively connected to the first ends of resistor R194 and resistor R195. The second ends of resistor R194 and resistor R195 are connected to the resolver output signal; The first-order active Butterworth filter and the first-order passive low-pass filter are cascaded to form the second-order Butterworth filter excitation circuit.

3. The resolver decoding circuit with high precision and anti-interference according to claim 1, characterized in that In the second-order Butterworth filter excitation circuit: The excitation signal EXC- is connected to the first end of resistor R253. The second end of resistor R253 is connected to the inverting input terminal of operational amplifier U8B. The inverting input terminal of operational amplifier U8B is respectively connected to the first ends of resistor R255 and capacitor C247. The output terminal of operational amplifier U8B is respectively connected to the second ends of resistor R255 and capacitor C247. The output terminal of operational amplifier U8B is also connected to the first end of resistor R193; The 8.8V voltage source is connected to the first end of resistor R252. The second end of resistor R252 is connected to the non-inverting input terminal of operational amplifier U8B; The non-inverting input terminal of operational amplifier U8B is connected to M15 ground through resistor R235; The negative and positive power supply terminals of operational amplifier U8B are respectively connected to the negative and positive power supply terminals of P15 power supply; thus forming a first-order active Butterworth filter; The first-order passive low-pass filter is composed of resistor R193 and capacitor C249. The second terminal of resistor R193 is connected to the first terminal of capacitor C249. The second terminal of capacitor C249 is connected to M15 ground. The second terminal of resistor R193 is connected to the non-inverting input terminal of operational amplifier U12B. The positive and negative power supply terminals of operational amplifier U12B are respectively connected to the positive and negative power supply terminals of P15 power supply. The inverting input terminal of operational amplifier U12B is connected to the output terminal, and the output terminal of operational amplifier U12B is respectively connected to the first terminals of resistor R196 and resistor R197. The second terminals of resistor R196 and resistor R197 are connected to the resolver output signal. The first-order active Butterworth filter and the first-order passive low-pass filter are cascaded to form a second-order Butterworth filter excitation circuit.

4. The high-precision anti-interference resolver decoding circuit according to claim 2 or 3, characterized in that, In the third-order active Butterworth filter receiving circuit: The SIN+ resolver signal of the third-order Butterworth filter receiving circuit is connected to the first terminal of resistor R180 and the first terminal of resistor R183. The second terminals of resistor R180 and resistor R183 are both connected to the first terminal of capacitor C115, the first terminal of resistor R181, and the inverting input terminal of amplifier U7B. The non-inverting input terminal of amplifier U7B is connected to the reference source VERF2.5V. The second terminal of capacitor C115 and the second terminal of resistor R181 are both connected to the output terminal of amplifier U7B and the first terminal of resistor R184, forming a first-order active Butterworth filter. The second terminal of resistor R184 is connected to the first terminal of capacitor C117, forming a first-order passive filtered Butterworth filter. The second terminal of resistor R184 is respectively connected to the first terminal of resistor R179 and the first terminal of resistor R185. The second terminal of capacitor C117 is connected to M ground. The second terminal of resistor R185 is respectively connected to the inverting input terminal of amplifier U8B and the first terminal of capacitor C116. The non-inverting input terminal of amplifier U8B is connected to the reference source VERF2.5V. The second terminal of capacitor C116 and the second terminal of resistor R179 are both connected to the output terminal of amplifier U8B. The output terminal of amplifier U8B is connected to AD2S1210, forming a first-order active Butterworth filter. Two groups of first-order active Butterworth filters and first-order passive filtered Butterworth filters are cascaded to form a third-order Butterworth filter.

5. The resolver decoding circuit with high precision and anti-interference according to claim 4, characterized in that, In the third-order active Butterworth filter receiving circuit: A capacitor C123 is provided between the SIN resolver signal and the SIN+ resolver signal of the third-order Butterworth filter receiving circuit. The SIN resolver signal is connected to the first ends of a resistor R189 and a resistor R191. The second ends of the resistor R189 and the resistor R191 are both connected to the first end of a capacitor C125, the first end of a resistor R190, and the inverting input terminal of an amplifier U7A. The non-inverting input terminal of the amplifier U7A is connected to a reference source VERF2.5V. The second ends of the capacitor C125 and the resistor R190 are both connected to the output terminal of the amplifier U7A and the first end of a resistor R192, forming a first-order active Butterworth filter. The second end of the resistor R192 is connected to the first end of a capacitor C130, forming a first-order passive filter Butterworth filter. The second end of the resistor R192 is respectively connected to the first end of a resistor R188 and the first end of a resistor R193. The second end of the capacitor C130 is connected to M ground. The second end of the resistor R193 is respectively connected to the inverting input terminal of an amplifier U8A and the first end of a capacitor C129. The non-inverting input terminal of the amplifier U8A is connected to a reference source VERF2.5V. The second ends of the capacitor C129 and the resistor R188 are both connected to the output terminal of the amplifier U8A. The output terminal of the amplifier U8A is connected to an AD2S1210, forming a first-order active Butterworth filter. Two groups of first-order active Butterworth filters and a first-order passive filter Butterworth filter are cascaded to form a third-order Butterworth filter.

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