Signal conversion system and method for incremental encoder of permanent magnet synchronous motor

Abstract

The invention discloses a signal conversion system for an incremental encoder of a permanent magnet synchronous motor. The signal conversion system comprises a first input interface, a second input interface, a differential-to-single-ended module, a storage module, an indicating lamp, a key, a programmable logic module, an analog switch, a single-ended-to-differential module, a first output interface and a second output interface, the first input interface is connected with the programmable logic module; the second input interface is connected with the programmable logic module through the differential-to-single-ended module; the storage module, the indicating lamp and the key are connected with the programmable logic module; the analog switch is respectively connected with the programmable logic module, the single-ended to differential module and the first output interface; the single-ended to differential module is connected with the second output interface; the first output interface is connected to a driver with a single-ended interface; and the second output interface is connected with a driver with a differential interface. Through the signal conversion method, rapid matching of different encoders and different motor drivers can be realized, and the development time of technicians is shortened.

Description

Technical Field

[0001] This invention relates to the field of encoder signal processing technology, and in particular to a signal conversion system and method for incremental encoders of permanent magnet synchronous motors. Background Technology

[0002] Permanent magnet synchronous motors, combined with encoders used to obtain the rotor position of permanent magnet synchronous motors, have become important motion actuators and are widely used in industries such as civilian robots, industrial equipment, and medical equipment.

[0003] To process encoder signals, the driver of a permanent magnet synchronous motor requires a corresponding processing circuit. Incremental encoders can output A, B, and Z pulse signals, where A and B are quadrature encoded signals and Z is the zero-point signal. Some incremental encoders can also output PWM signals to indicate the rotor's static position. Furthermore, the electrical signal format of incremental encoder output signals can be divided into open-collector output and differential output. Traditionally, in development, engineers need to redesign the encoder processing circuit on the motor drive board and match the encoder interface to accommodate different incremental encoder output formats and electrical signal forms. This increases development costs and time. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a signal conversion system and method for incremental encoders of permanent magnet synchronous motors, thereby solving the technical problem that existing technologies require redesigning circuits and interfaces according to requirements, resulting in high development costs.

[0005] This invention provides a signal conversion system for an incremental encoder of a permanent magnet synchronous motor, comprising: a first input interface, a second input interface, a differential to single-ended module, a storage module, an indicator light, a button, a programmable logic module, an analog switch, a single-ended to differential module, a first output interface, and a second output interface;

[0006] The first input interface is connected to the programmable logic module (PLM) and is used to connect an incremental quadrature encoder that outputs a single-ended level signal. The second input interface is connected to the PLM via a differential-to-single-ended module. The second input interface is used to connect an incremental quadrature encoder that outputs a differential level signal. The differential-to-single-ended module is used to convert the differential signal into a single-ended signal. The storage module is connected to the PLM and is used to store the recognition results of the input signal and the mapping relationship between the input and output. Analog switches are connected to the PLM, the single-ended-to-differential module, and the first output interface, respectively, and are used to switch the output interface of the output signal according to the output port selection signal of the PLM. An indicator light is connected to the PLM and is used to indicate the input signal recognition status and whether the input signal recognition result data is already in the storage module. A button is connected to the PLM and is used to start the input signal recognition process. The PLM is used to form a mapping between the input signal and the output signal according to actual needs and to generate an output port selection signal. The single-ended-to-differential module is connected to the second output interface and is used to convert the single-ended signal into a differential signal. The first output interface is connected to a driver with a single-ended interface. The second output interface is connected to a driver with a differential interface.

[0007] Furthermore, the incremental encoder signal conversion system for the permanent magnet synchronous motor also includes: a DIP switch; the DIP switch is connected to the programmable logic module and is used to manually control the output port selection signal generated by the programmable logic module.

[0008] Furthermore, the first input interface is packaged as DB9; the second input interface is packaged as DB15.

[0009] Furthermore, the input of the programmable logic module is four signals, which include: A-phase quadrature signal, B-phase quadrature signal, Z zero-point signal and PWM static angle signal, or A-phase quadrature signal, B-phase quadrature signal, Z zero-point signal and empty signal.

[0010] Furthermore, the output of the programmable logic module is four signals, which include: A-phase quadrature signal, B-phase quadrature signal, Z zero-point signal and PWM static angle signal, or A-phase quadrature signal, B-phase quadrature signal, Z zero-point signal and empty signal.

[0011] The present invention also provides a signal conversion method for an incremental encoder of a permanent magnet synchronous motor, applicable to the signal conversion system of the incremental encoder of the permanent magnet synchronous motor, the method comprising: an initialization process, an output selection process, an input signal identification process, and an output signal mapping process;

[0012] The initialization process includes:

[0013] Connect the encoder of the permanent magnet synchronous motor to the corresponding input interface according to its type;

[0014] If the storage module does not contain input signal identification result data, or if the stored input signal identification result data does not match the connected permanent magnet synchronous motor, then the input signal identification process is executed.

[0015] The output selection process includes:

[0016] Connect the corresponding output interface according to the type of the permanent magnet synchronous motor drive board, and control the analog switch through the programmable logic module to transmit the output signal to the output interface connected to the drive board;

[0017] The input signal identification process includes the following steps:

[0018] Step A1: Control the connected drive board in angle open-loop mode and drive the permanent magnet synchronous motor to rotate in the forward direction;

[0019] Step A2: Capture the rising or falling edges of the four input signals respectively, and count them;

[0020] When the count values ​​corresponding to three input signals are all greater than or equal to N, the counting stops, and the input signal with a count value of N is designated as the Z zero-point signal, and the input signal with a count value of 0 is designated as the PWM static angle signal or an empty signal.

[0021] Step A3: Initially set one of the two input signals with count values ​​greater than N as phase A quadrature signal and the other input signal as phase B quadrature signal, and continue counting using the quadrature counting method;

[0022] When the count value increases positively, the initial setting is correct. Set one input signal as phase A quadrature signal and the other input signal as phase B quadrature signal.

[0023] When the count value decreases in the opposite direction, a preliminary setting error is found, and one input signal is set as a B-phase quadrature signal and the other input signal is set as an A-phase quadrature signal.

[0024] Step A4: Generate an output port selection signal according to the type of the connected driver board, and store the input signal identification result data;

[0025] The output signal mapping process includes: establishing a mapping relationship between the identified input signals and the output signals according to the signal connection order required by the driver board.

[0026] Furthermore, in step 1, the permanent magnet synchronous motor is driven to rotate in the opposite direction;

[0027] In step 3, when the count value increases positively, an initial error is set, and one input signal is set as a B-phase quadrature signal and the other input signal is set as an A-phase quadrature signal.

[0028] When the count value decreases in the opposite direction, the initial setting is correct. One input signal is set as the A-phase quadrature signal, and the other input signal is set as the B-phase quadrature signal.

[0029] Furthermore, in step 2, N is a natural number, and N is greater than or equal to 2.

[0030] Furthermore, during the input signal identification process, the output corresponding to the input signal that has not been identified is in a high-impedance state.

[0031] The beneficial effects of this invention are:

[0032] This invention adds a permanent magnet synchronous motor incremental encoder signal conversion system, which is connected between the motor and the motor driver. The conversion system can process different types of encoder signals into single-ended or differential signals that the original motor driver can handle, achieving low-cost and rapid matching between the two.

[0033] This invention can not only help to achieve effective connection of different encoder electrical signals between the motor and the motor drive board, but also, by identifying the signal content, adjust the order of the first to fourth output information one by one according to the electrical signal content expected by the motor drive board.

[0034] This invention uses a programmable logic module as its core, and does not cause signal transmission delay or loss during the process of establishing the mapping between input and output signals.

[0035] This invention counts the rising or falling edges of the input signal, determines the signal content based on the counting results, and uses an orthogonal counting method to finally determine the orthogonal information of phase A and phase B, thus achieving fast and accurate identification of the input signal.

[0036] This invention incorporates functions such as identification information storage, status indication, and key triggering, making it convenient for users to quickly match. Attached Figure Description

[0037] The features and advantages of the invention will be more clearly understood by referring to the accompanying drawings, which are schematic and should not be construed as limiting the invention in any way. In the drawings:

[0038] Figure 1 This is a system block diagram of a specific implementation of the present invention;

[0039] Figure 2 This is a connection diagram of a specific embodiment 1 of the present invention;

[0040] Figure 3 This is a connection diagram of a specific embodiment 2 of the present invention. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0042] The present invention will be further illustrated below with reference to specific embodiments. Those skilled in the art should understand that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Modifications to the present invention in various equivalent forms all fall within the scope defined by the appended claims.

[0043] like Figure 1 As shown, the present invention provides a signal conversion system for an incremental encoder of a permanent magnet synchronous motor, comprising: a programmable logic module, a storage module, a first input port, a second input port, a differential to single-ended module, an analog switch, a single-ended to differential module, a first output port, a second output port, a first button, a second button, a first indicator light, a second indicator light, and an output selection DIP switch;

[0044] The first input port is connected to the programmable logic module and is used to input an incremental quadrature encoder that outputs a single-ended level signal and send the input signal to the programmable logic module. The preferred interface package for the first input port is DB9. The second input port is connected to the programmable logic module through a differential-to-single-ended module. The second input port is used to input an incremental quadrature encoder that outputs a differential level signal. The differential-to-single-ended module is used to convert the differential signal into a single-ended signal and send the converted input signal to the programmable logic module. The signal from the first input port to the programmable logic module, or the signal from the second input port after conversion by the differential-to-single-ended module and then sent to the programmable logic module, are all four signals: the first input signal, the second input signal, the third input signal, and the fourth input signal. These four signals can be matched with quadrature encoders whose signal content is A-phase quadrature signal, B-phase quadrature signal, Z-zero signal, and PWM static angle signal, or with quadrature encoders whose signal content is A-phase quadrature signal, B-phase quadrature signal, and Z-zero signal.

[0045] Both the first button and the second button are connected to the programmable logic module. The first button is used to start input signal recognition and learning, and the second button is used to trigger the storage function.

[0046] Both the first indicator light and the second indicator light are connected to the programmable logic module. The first indicator light is used to indicate the input signal identification status, and the second indicator light is used to indicate whether the input signal identification result data is already in the storage module.

[0047] The analog switch is connected to the programmable logic module, the single-ended to differential module and the first output interface respectively, and is used to switch the output interface of the output signal according to the output port selection signal of the programmable logic module.

[0048] The single-ended to differential module is connected to the second output port and the analog switch respectively. When differential output is selected, it converts the output signal of the programmable logic module into a differential signal and outputs it from the second output port.

[0049] The output selection DIP switch is connected to the programmable logic module. When the output selection DIP switch is in the OFF position, it outputs from the first output port in a single-ended manner; when the output selection DIP switch is in the ON position, it outputs differentially from the second output port.

[0050] The storage module is connected to the programmable logic module and is used to store the recognition results of the input signals and the mapping relationship between input and output.

[0051] The programmable logic module is preferably a general-purpose logic control chip device such as FPGA or CPLD; the differential to single-ended module is preferably AM26LS32A, which can simultaneously realize 4-channel differential to single-ended function; the single-ended to differential module is preferably AM26LS31, which can simultaneously realize 4-channel single-ended to differential function; the analog switch is preferably SGM4874, which contains four single-pole double-throw analog switches.

[0052] Example 1:

[0053] like Figure 2 As shown, the encoder signal content and sequence of the permanent magnet synchronous motor are PWM static angle signal, Z zero point signal, B phase quadrature signal, and A phase quadrature signal; the electrical form of the signal is single-ended, and the encoder accuracy is 1024 lines.

[0054] The encoder interface of the motor drive board can process differential encoder signals. The signal content and sequence are as follows: A-phase quadrature signal (differential signals A+, A-), B-phase quadrature signal (differential signals B+, B-), Z-zero signal (differential signals Z+, Z-), and PWM static angle signal (differential signals PWM+, PWM-).

[0055] At this point, the conversion method is as follows:

[0056] Initialization process:

[0057] Connect the encoder of the target permanent magnet synchronous motor to the first input port; connect the three-phase wires of the target permanent magnet synchronous motor to the target motor drive board;

[0058] Confirm the status of the second indicator light. When the second indicator light is on, it means that input signal recognition result data has been stored; when the second indicator light is off, it means that no input signal recognition result data has been stored.

[0059] If no input signal identification result data is stored, or if the stored input signal identification result data does not match the target permanent magnet synchronous motor or the target motor drive board, the input signal identification process must be executed.

[0060] Output selection process:

[0061] Since the target motor drive board can only process differential encoder signals, connect the second output port of the permanent magnet synchronous motor incremental encoder signal conversion system to the target motor drive board and set the output selection DIP switch to the ON position.

[0062] Output signal mapping process:

[0063] The sequence of the encoder port signals of the target motor drive board is determined, and the content of the encoder port signals of the target motor drive board corresponds to the output signals of the conversion system: the first output signal corresponds to the A-phase quadrature signal, the second output signal corresponds to the B-phase quadrature signal, the third output signal corresponds to the Z zero point signal, and the fourth output signal corresponds to the PWM static angle signal. The corresponding information is then programmed into the programmable logic module.

[0064] Input signal identification process:

[0065] Since common encoder interfaces do not label the signal content, technicians cannot obtain it directly, so signal identification is required;

[0066] Step A1: Control the target motor drive board to be in angle open-loop mode and drive the permanent magnet synchronous motor to rotate in the forward direction;

[0067] Step A2: Press the first button to activate the input signal recognition function;

[0068] Step A3: The programmable logic module captures the rising or falling edges of the first input signal, the second input signal, the third input signal, and the fourth input signal, and counts them;

[0069] The counting stops when the count values ​​of three input signals are all greater than or equal to 2. For example, if the first input signal has a count value of 0 (because it's a PWM static angle signal, it won't output a PWM signal during motor rotation, only a high or low level); the second input signal has a count value of 2; the third input signal has a count value greater than 1024 and less than 2048 (2 x 1024); and the fourth input signal has a count value greater than 1024 and less than 2048, then the second input signal with a count value of 2 is determined to be the Z-zero signal, and the first input signal with a count value of 0 is the PWM static angle signal.

[0070] Step A4: In step A3, for the two input signals with a count value greater than 2, we first assume that the content of the third input signal is an A-phase quadrature signal and the content of the fourth input signal is a B-phase quadrature signal. The programmable logic module continues to count the two input signals using the quadrature counting method. The counting result is that the count value decreases in the opposite direction. At this point, it is determined that the previous assumption was incorrect and corrected to the fourth input signal being an A-phase quadrature signal and the third input signal being a B-phase quadrature signal.

[0071] Step A5: Using a programmable logic module, logically connect the first input signal, the second input signal, the third input signal, the fourth input signal, and the first output signal, the second output signal, the third output signal, and the fourth output signal according to the signal content; that is, connect the first input signal and the fourth output signal, connect the second input signal and the third output signal, connect the third input signal and the second output signal, and connect the fourth input signal and the first output signal.

[0072] Step A6: Based on the state of the output selection DIP switch, the programmable logic module controls the analog switch to select the output signal from the second output port; during input signal identification, the first, second, third, and fourth output signals that have not been identified all output a high impedance state.

[0073] Step A7: Press the second button to trigger the storage function. The programmable logic module controls the storage of the logical connection information in step A5 to the storage module.

[0074] Example 2:

[0075] like Figure 3 As shown, the encoder signal content and sequence of the permanent magnet synchronous motor are A-phase quadrature signal, B-phase quadrature signal, and Z-phase zero signal. The electrical form of the signal is differential, and the encoder accuracy is 512 lines.

[0076] The encoder interface of the motor drive board can process single-ended encoder signals, and the signal content includes sequenced empty signals, Z zero-point signals, B-phase quadrature signals, and A-phase quadrature signals.

[0077] At this point, the conversion method is as follows:

[0078] Initialization process:

[0079] Connect the encoder of the target permanent magnet synchronous motor to the second input port; connect the three-phase wires of the target permanent magnet synchronous motor to the target motor drive board;

[0080] Confirm the status of the second indicator light. When the second indicator light is on, it means that input signal recognition result data has been stored; when the second indicator light is off, it means that no input signal recognition result data has been stored.

[0081] If no input signal identification result data is stored, or if the stored input signal identification result data does not match the target permanent magnet synchronous motor or the target motor drive board, the input signal identification process must be executed.

[0082] Output selection process:

[0083] Since the target motor drive board can only process single-ended encoder signals, connect the first output port of the permanent magnet synchronous motor incremental encoder signal conversion system to the target motor drive board and set the output selection DIP switch to the OFF position.

[0084] Output signal mapping process:

[0085] The sequence of the encoder port signals of the target motor drive board is determined, and the content of the encoder port signals of the target motor drive board corresponds to the output signals of the conversion system: the first output signal corresponds to the empty signal, the second output signal corresponds to the Z zero point signal, the third output signal corresponds to the B phase quadrature signal, and the fourth output signal corresponds to the A phase quadrature signal. The corresponding information is then programmed into the programmable logic module.

[0086] Input signal identification process:

[0087] Since common encoder interfaces do not label the signal content, technicians cannot obtain it directly, so signal identification is required;

[0088] Step B1: Control the target motor drive board to be in angle open-loop mode and drive the permanent magnet synchronous motor to rotate in the forward direction;

[0089] Step B2: Press the first button to activate the input signal recognition function;

[0090] Step B3: The programmable logic module captures the rising or falling edges of the first, second, third, and fourth input signals and counts them;

[0091] When the count values ​​of three input signals are all greater than or equal to 3, the counting stops. For example, if the count value of the first input signal is greater than 1024 (2x512) and less than 1536 (3x512), the count value of the second input signal is greater than 1024 and less than 1536, the count value of the third input signal is 3, and the count value of the fourth input signal is 0, then it can be determined that the content of the third input signal with a count value of 3 is the Z zero-point signal, and the fourth input signal with a count value of 0 is an empty signal.

[0092] Step B4: In step B3, for the two input signals with a count value greater than 3, let's assume that the content of the first input signal is an A-phase quadrature signal and the content of the second input signal is a B-phase quadrature signal. The programmable logic module continues to count the two input signals using the quadrature counting method. The counting result is: the count value increases positively, so the previous assumption is correct, that is, the content of the first input signal is an A-phase quadrature signal and the content of the second input signal is a B-phase quadrature signal.

[0093] Alternatively, if the permanent magnet synchronous motor is driven to rotate in reverse in step B1, let's assume that the content of the first input signal is an A-phase quadrature signal and the content of the second input signal is a B-phase quadrature signal. The programmable logic module continues to count the two input signals using the quadrature counting method. The counting result is that the count value decreases in the reverse direction, so the previous assumption is correct, that is, the content of the first input signal is an A-phase quadrature signal and the content of the second input signal is a B-phase quadrature signal.

[0094] Step B5: Using a programmable logic module, logically connect the first input signal, the second input signal, the third input signal, the fourth input signal, and the first output signal, the second output signal, the third output signal, and the fourth output signal according to the signal content; that is, connect the first input signal and the fourth output signal, connect the second input signal and the third output signal, connect the third input signal and the second output signal, and connect the fourth input signal and the first output signal.

[0095] Step B6: Based on the state of the output selection DIP switch, the programmable logic module controls the analog switch to select the output signal from the first output port; during input signal identification, if the first, second, third, and fourth output signals are not completely identified, they all output a high-impedance state.

[0096] Step B7: Press the second button to trigger the storage function. The programmable logic module controls the storage of the logical connection information in step B5 to the storage module.

[0097] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A signal conversion system for an incremental encoder of a permanent magnet synchronous motor, characterized in that, include: The system includes a first input interface, a second input interface, a differential-to-single-ended converter, a storage module, indicator lights, buttons, a programmable logic module, an analog switch, a single-ended-to-differential converter, a first output interface, and a second output interface. The first input interface is connected to the programmable logic module and is used to connect an incremental quadrature encoder that outputs a single-ended level signal. The second input interface is connected to the programmable logic module via a differential-to-single-ended module. This second input interface is used to connect to an incremental quadrature encoder that outputs differential level signals. The differential-to-single-ended module converts the differential signal into a single-ended signal. The storage module is connected to the programmable logic module and stores the recognition results of the input signal and the mapping relationship between input and output. Analog switches are connected to the programmable logic module, the single-ended-to-differential module, and the first output interface, respectively, and are used to switch the output interface of the output signal according to the output selection signal of the programmable logic module. An indicator light is connected to the programmable logic module and indicates the input signal recognition status and whether the storage module already contains the input signal recognition result data. A button is connected to the programmable logic module and is used to start the input signal recognition process. Programmable logic modules are used to map input signals to output signals according to actual needs and generate output port selection signals; The single-ended to differential module is connected to the second output interface to convert a single-ended signal into a differential signal; the first output interface is connected to a driver with a single-ended interface. The second output interface connects to a driver with a differential interface.

2. The incremental encoder signal conversion system for permanent magnet synchronous motors as described in claim 1, characterized in that, The signal conversion system of the incremental encoder for permanent magnet synchronous motor also includes: a DIP switch; the DIP switch is connected to the programmable logic module and is used to manually control the output port selection signal generated by the programmable logic module.

3. The incremental encoder signal conversion system for permanent magnet synchronous motors as described in claim 1, characterized in that, The first input interface is packaged as DB9; the second input interface is packaged as DB15.

4. The incremental encoder signal conversion system for permanent magnet synchronous motors as described in claim 1, characterized in that, The input to the programmable logic module is four signals, which include: A-phase quadrature signal, B-phase quadrature signal, Z zero-point signal and PWM static angle signal, or A-phase quadrature signal, B-phase quadrature signal, Z zero-point signal and empty signal.

5. The incremental encoder signal conversion system for permanent magnet synchronous motors as described in claim 1 or 4, characterized in that, The output of the programmable logic module is four signals, including: A-phase quadrature signal, B-phase quadrature signal, Z zero-point signal and PWM static angle signal, or A-phase quadrature signal, B-phase quadrature signal, Z zero-point signal and no signal.

6. A signal conversion method for an incremental encoder of a permanent magnet synchronous motor, applicable to the signal conversion system of an incremental encoder of a permanent magnet synchronous motor as described in any one of claims 1-5, characterized in that, The method includes: an initialization process, an output selection process, an input signal discrimination process, and an output signal mapping process; The initialization process includes: Connect the encoder of the permanent magnet synchronous motor to the corresponding input interface according to its type; If the storage module does not contain input signal identification result data, or if the stored input signal identification result data does not match the connected permanent magnet synchronous motor, then the input signal identification process is executed. The output selection process includes: Connect the corresponding output interface according to the type of the permanent magnet synchronous motor drive board, and control the analog switch through the programmable logic module to transmit the output signal to the output interface connected to the drive board; The input signal identification process includes the following steps: Step A1: Control the connected drive board in angle open-loop mode and drive the permanent magnet synchronous motor to rotate in the forward direction; Step A2: Capture the rising or falling edges of the four input signals respectively, and count them; When the count values ​​corresponding to three input signals are all greater than or equal to N, the counting stops, and the input signal with a count value of N is designated as the Z zero-point signal, and the input signal with a count value of 0 is designated as the PWM static angle signal or an empty signal. Step A3: Initially set one of the two input signals with count values ​​greater than N as phase A quadrature signal and the other input signal as phase B quadrature signal, and continue counting using the quadrature counting method; When the count value increases positively, the initial setting is correct. Set one input signal as phase A quadrature signal and the other input signal as phase B quadrature signal. When the count value decreases in the opposite direction, a preliminary setting error is found, and one input signal is set as a B-phase quadrature signal and the other input signal is set as an A-phase quadrature signal. Step A4: Generate an output port selection signal according to the type of the connected driver board, and store the input signal identification result data; The output signal mapping process includes: establishing a mapping relationship between the identified input signals and the output signals according to the signal connection order required by the driver board.

7. The signal conversion method for incremental encoder of permanent magnet synchronous motor as described in claim 6, characterized in that, In step 1, the permanent magnet synchronous motor is driven to rotate in the opposite direction. In step 3, when the count value increases positively, an initial error is set, and one input signal is set as a B-phase quadrature signal and the other input signal is set as an A-phase quadrature signal. When the count value decreases in the opposite direction, the initial setting is correct. One input signal is set as the A-phase quadrature signal, and the other input signal is set as the B-phase quadrature signal.

8. The signal conversion method for incremental encoder of permanent magnet synchronous motor as described in claim 6, characterized in that, In step 2, N is a natural number, and N is greater than or equal to 2.

9. The signal conversion method for incremental encoder of permanent magnet synchronous motor as described in claim 6, characterized in that, During the input signal identification process, the output corresponding to the input signal that has not been identified is in a high-impedance state.

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