Permanent magnet synchronous motor single current sensor control method and system based on discrete current state observer

Abstract

The invention provides a permanent magnet synchronous motor single current sensor control method and system based on a discrete current state observer, and the method employs a single-phase current sensor to complete the stable control of a PMSM. The single-phase current obtained by the current sensor and the other two-phase current obtained by prediction at the previous moment enter the current state observer to predict the current at the next moment. Stable operation of the PMSM can be ensured while the cost of the sensor is reduced, and the method has engineering application potential.

Description

Technical Field

[0001] The present invention relates to the field of PMSM, and in particular to a single current sensor control method and system for a permanent magnet synchronous motor based on a discrete current state observer. Background Art

[0002] Permanent magnet synchronous motor (PMSM) has the advantages of high power density, high efficiency, good reliability, and fast dynamic response, and is widely used in servo drive, rail transportation, and new energy generation. The PMSM drive system relies on accurate stator phase current information to achieve high-precision control. Usually, a three-phase PMSM drive system requires at least two phase current sensors to obtain accurate stator current signals.

[0003] However, in harsh working environments, current sensors are prone to failure or noise interference, resulting in inaccurate current signals, which in turn affects the control performance of the system. At the same time, the device volume and the cost of sensors, circuit wiring, etc. must also be considered in practical applications. Therefore, how to minimize the number of sensors while ensuring continuous and reliable operation of the motor drive system has become an urgent problem to be solved. Summary of the invention

[0004] The purpose of the present invention is to propose a single current sensor control method and system for a permanent magnet synchronous motor based on a discrete current state observer; the method successfully reconstructs a three-phase current signal through a single DC bus current sensor or a single-phase current sensor, and can realize closed-loop current control in a PMSM drive system using only one hardware current sensor.

[0005] To achieve the above object, the technical solution of the present invention is as follows:

[0006] In a first aspect, the present invention proposes a single current sensor control method for a permanent magnet synchronous motor based on a discrete current state observer, comprising the following steps:

[0007] Step S1: Collect the A phase current i of PMSM a 、PMSM voltage u in dq coordinate system d and u q , PMSM speed n, electrical angular velocity ω e and electrical angle θ e The value i at time k a (k),u d (k),u q (k), n(k), ω e (k),θ e (k);

[0008] Step S2: Use the B-phase current and C-phase current of the PMSM at time k predicted in the previous control cycle and and θ e (k) and i a (k) Perform Clark transformation and Park transformation to obtain the current i of the PMSM in the dq coordinate system at time k d (k) and i q (k);

[0009] Step S3: According to the equation of the current observer, use the discretization method and utilize u d (k),u q (k),ω e (k), i d (k), i q (k) Predict the current of PMSM in dq coordinate system at time k+1 and

[0010] Step S4: Collect the electrical angle θ of the PMSM at time k+1 e (k+1), using and Perform inverse Park transform and inverse Clark transform to obtain the current of PMSM at time k+1 in the abc coordinate system and Used in the next control cycle;

[0011] Step S5: Set the reference value n of the speed ref and n(k) are input to the speed controller, and the reference value i of the output current is adjusted by PI. d_ref and i q_ref ;

[0012] Step S6: The obtained values ​​in steps S3 and S5 are i d_ref and i q_ref As the input of the current regulator, the voltage u of the PMSM in the dq coordinate system at time k+1 is output after PI regulation. d (k+1) and u q (k+1);

[0013] Step S7: Using θ e (k+1),u d (k+1) and u q (k+1) performs inverse Park transformation to obtain the voltage component u of the PMSM in the α-β coordinate system at time k+1 α (k+1) and u β (k+1);

[0014] Step S8: According to u α (k+1) and u β (k+1) performs SVPWM modulation to output the corresponding square wave to control the switching of the six IGBT tubes of the inverter and control the motor.

[0015] Preferably, the step S2 specifically comprises: and θ e (k), i a (k) Substitute the following equation to obtain the current of the PMSM in the dq coordinate system at time k;

[0016]

[0017] Where: i α and i β Represents the current component in the α-β coordinate system.

[0018] Preferably, the step S3 specifically comprises: discretizing the observer equation and using u d (k),u q (k),ω e (k), i d (k), i q (k) Predict the current at time k+1 and

[0019]

[0020] Where: Represents the state estimation vector, i d and i q The predicted value; A, B and C are parameter matrices; u represents the input vector; y represents the output vector; K is the gain matrix of the observer; the details are as follows:

[0021]

[0022] Where: L d and L q are the inductances in the dq axis respectively; ψ f is the permanent magnet flux; R s is the stator resistance.

[0023] Preferably, the step S3 adopts the forward Euler discretization method according to u d (k),u q (k),ω e (k), i d (k), i q (k) Predict the current at time k+1 and

[0024]

[0025] Where: subscript FE represents the observer equation discretized using the forward Euler discretization method, T s Indicates the system sampling time.

[0026] Preferably, step S3 uses Tustin discrete method according to u d (k),u q (k),ω e (k), i d (k), i q (k) Predict the current at time k+1 and

[0027]

[0028]

[0029] Where: the subscript Tustin represents the use of Tustin discretization method to discretize the observer equation, I is the unit matrix, T s Indicates the system sampling time.

[0030] Preferably, step S3 adopts a mixed discrete method according to u d (k),u q (k),ω e (k), i d (k), i q (k) Predict the current at time k+1 and

[0031]

[0032] Where: the subscript HY represents the observer equation discretized using the hybrid discretization method, T s Indicates the system sampling time.

[0033] Preferably, step S3 uses a matching pole-zero discrete method according to u d (k),u q (k),ω e (k), i d (k), i q (k) Predict the current at time k+1 and

[0034]

[0035]

[0036] Where: subscript MPZ represents the observer equation discretized using the matched pole-zero discretization method, T s Represents the system sampling time, and a and b are intermediate parameters.

[0037] Preferably, the step S4 is specifically as follows: e (k+1), and Perform inverse Park transform and inverse Clark transform to obtain the current in the abc coordinate system;

[0038]

[0039] Where: i α and i β Represents the current component in the α-β coordinate system.

[0040] Preferably, the step S7 specifically comprises: e (k+1),u d (k+1) and u q (k+1) Perform inverse Park transform to get u α (k+1) and u β (k+1);

[0041]

[0042] In the second aspect, the present invention proposes a permanent magnet synchronous motor single current sensor control system based on a discrete current state observer, comprising a processor, a memory and a computer program stored on the memory. When the processor executes the computer program, it specifically executes the steps in the above-mentioned permanent magnet synchronous motor single current sensor control method based on a discrete current state observer.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] The present invention relates to a single current sensor control method and system for a permanent magnet synchronous motor based on a discrete current state observer, wherein the single-phase current obtained by the current sensor and the other two-phase currents predicted at the previous moment enter the current state observer to predict the current at the next moment. The present invention can reduce the cost of the sensor while ensuring the stable operation of the PMSM, and has engineering application potential. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 is a control scheme diagram in one embodiment of the present invention;

[0046] Figure 2 is a flow chart of a method in one embodiment of the present invention;

[0047] Figure 3is a discretization error diagram of different discretization methods at different sampling frequencies in one embodiment of the present invention;

[0048] Figure 4 1 is a discrete time pole migration diagram at different sampling frequencies when the rotation speed increases in one embodiment of the present invention. DETAILED DESCRIPTION

[0049] The technical solution of the present invention is described in detail below in conjunction with the accompanying drawings.

[0050] Reference Figure 1 The present invention provides an inverter circulating current suppression method based on model prediction virtual voltage vector control, which can complete the stable control of PMSM using only one single-phase current sensor, including the following steps:

[0051] Step S1: Collect the A phase current i of PMSM a 、PMSM voltage u in dq coordinate system d and u q , PMSM speed n, electrical angular velocity ω e and electrical angle θ e The value i at time k a (k) and u d (k) and u q (k), n(k), ω e (k),θ e (k);

[0052] Step S2: Use the B-phase current and C-phase current of the PMSM at time k predicted in the previous control cycle and and θ e (k) and i a (k) Perform Clark transformation and Park transformation to obtain the current i of the PMSM in the dq coordinate system at time k d (k) and i q (k);

[0053] Step S3: According to the equation of the current observer, use the exact discretization method and utilize u d (k) and u q (k),ω e (k), i d (k), i q (k) Predict the current of PMSM in dq coordinate system at time k+1 and

[0054] Step S4: Collect the electrical angle θ of the PMSM at time k+1 e (k+1), using and Perform inverse Park transform and inverse Clark transform to obtain the current of PMSM at time k+1 in the abc coordinate system and Used in the next control cycle;

[0055] Step S5: Set the reference value n of the speed ref and n(k) are input to the speed controller, and the reference value i of the output current is adjusted by PI. d_ref and i q_ref ;

[0056] Step S6: The obtained values ​​in steps S3 and S5 are i d_ref and i q_ref As the input of the current regulator, the voltage u of the PMSM in the dq coordinate system at time k+1 is output after PI regulation. d (k+1) and u q (k+1);

[0057] Step S7: Using θ e (k+1),u d (k+1) and u q (k+1) performs inverse Park transformation to obtain the voltage component u of the PMSM in the α-β coordinate system at time k+1 α (k+1) and u β (k+1);

[0058] Step S8: According to u α (k+1) and u β (k+1) performs SVPWM modulation to output the corresponding square wave to control the switching of the six IGBT tubes of the inverter and further control the motor.

[0059] In this embodiment, the step S2 is specifically: and θ e (k), i a (k) Substitute into the following equation to obtain the current in the dq coordinate system;

[0060]

[0061] Where: i α and i β Represents the current component in the α-β coordinate system.

[0062] In this embodiment, step S3 specifically includes: discretizing the observer equation and using u d (k),u q (k),ω e (k), i d (k), iq (k) Predict the current at time k+1 and

[0063]

[0064] in:

[0065]

[0066] Where: L d and L q are the inductances in the dq axis respectively; ψ f is the permanent magnet flux; R s is the stator resistance; K is the gain matrix of the observer; Represents the state estimation vector, i d and i q The predicted value of ; A, B and C are all parameter matrices; u represents the input vector; y represents the output vector.

[0067] The discretization methods include forward Euler discretization (FE), Tustin discretization, hybrid discretization (HY) and matched pole-zero discretization (MPZ). d (k),u q (k),ω e (k), i d (k), i q (k) Predict the current at time k+1 and The details are as follows:

[0068]

[0069] FE, Tustin, HY and MPZ represent the observer equations discretized using forward Euler discretization, Tustin discretization, hybrid discretization and matched pole-zero discretization, respectively; T s represents the system sampling time; I is the unit matrix, and a and b are intermediate parameters.

[0070] In this embodiment, the step S4 is specifically as follows: e (k+1), and Perform inverse Park transform and inverse Clark transform to obtain the current in the abc coordinate system.

[0071]

[0072] Where: i α and i β Represents the current component in the α-β coordinate system.

[0073] In this embodiment, the step S7 is specifically as follows: e (k+1),u d (k+1) and u q (k+1) Perform inverse Park transform to get u α (k+1) and u β (k+1).

[0074]

[0075] According to u α (k+1) and u β (k+1) performs SVPWM modulation to output the corresponding square wave to control the switching of the six IGBT tubes of the inverter and further control the motor. This process is repeated to achieve stable operation of PMSM.

[0076] The present invention also proposes a permanent magnet synchronous motor single current sensor control system based on a discrete current state observer, comprising a processor, a memory and a computer program stored in the memory. When the processor executes the computer program, it specifically executes the steps in the above-mentioned permanent magnet synchronous motor single current sensor control method based on a discrete current state observer.

[0077] The above are preferred embodiments of the present invention. Any changes made according to the technical solution of the present invention, as long as the resulting functions do not exceed the scope of the technical solution of the present invention, belong to the protection scope of the present invention.

Claims

1. A single current sensor control method for a permanent magnet synchronous motor based on a discrete current state observer, characterized in that: The control method uses a single-phase current sensor to complete the stable control of the PMSM, and includes the following steps: Step S1: Collect the A phase current i of PMSM a 、PMSM voltage u in dq coordinate system d and u q , PMSM speed n, electrical angular velocity ω e and electrical angle θ e The value i at time k a (k) and u d (k) and u q (k), n(k), ω e (k),θ e (k); Step S2: Use the B-phase current and C-phase current of the PMSM at time k predicted in the previous control cycle and and θ e (k) and i a (k) Perform Clark transformation and Park transformation to obtain the current i of the PMSM in the dq coordinate system at time k d (k) and i q (k); Step S3: According to the equation of the current observer, use the discretization method and utilize u d (k) and u q (k),ω e (k), i d (k), i q (k) Predict the current of PMSM in dq coordinate system at time k+1 and Step S4: Collect the electrical angle θ of the PMSM at time k+1 e (k+1), using and Perform inverse Park transform and inverse Clark transform to obtain the current of PMSM at time k+1 in the abc coordinate system and Used in the next control cycle; Step S5: Set the reference value n of the speed ref and n(k) are input to the speed controller, and the reference value i of the output current is adjusted by PI. d_ref and i q_ref ; Step S6: The obtained values ​​in steps S3 and S5 are i d_ref and i q_ref As the input of the current regulator, the voltage u of the PMSM in the dq coordinate system at time k+1 is output after PI regulation. d (k+1) and u q (k+1); Step S7: Using θ e (k+1),u d (k+1) and u q (k+1) performs inverse Park transformation to obtain the voltage component u of the PMSM in the α-β coordinate system at time k+1 α (k+1) and u β (k+1); Step S8: According to u α (k+1) and u β (k+1) performs SVPWM modulation to output the corresponding square wave to control the switching of the six IGBT tubes of the inverter and control the motor.

2. The method for controlling a permanent magnet synchronous motor with a single current sensor based on a discrete current state observer according to claim 1, characterized in that: The step S2 specifically comprises: and θ e (k), i a (k) Substitute the following equation to obtain the current of the PMSM in the dq coordinate system at time k; Where: i α and i β Represents the current component in the α-β coordinate system.

3. The method for controlling a permanent magnet synchronous motor with a single current sensor based on a discrete current state observer according to claim 1, characterized in that: The step S3 is specifically as follows: discretizing the observer equation and using u d (k) and u q (k),ω e (k), i d (k), i q (k) Predict the current at time k+1 and y(k)=Cx(k) Where: Represents the state estimation vector, i d and i q The predicted value; A, B and C are parameter matrices; u represents the input vector; y represents the output vector; K is the gain matrix of the observer; the details are as follows: Where: L d and L q are the inductances in the dq axis respectively; ψ f is the permanent magnet flux; R s is the stator resistance.

4. The method for controlling a permanent magnet synchronous motor with a single current sensor based on a discrete current state observer according to claim 3, characterized in that: The step S3 adopts the forward Euler discretization method to calculate u d (k) and u q (k),ω e (k), i d (k), i q (k) Predict the current at time k+1 and Where: subscript FE represents the observer equation discretized using the forward Euler discretization method, T s Indicates the system sampling time.

5. The method for controlling a permanent magnet synchronous motor with a single current sensor based on a discrete current state observer according to claim 3, characterized in that: Step S3 uses Tustin discrete method to calculate u d (k) and u q (k),ω e (k), i d (k), i q (k) Predict the current at time k+1 and Where: the subscript Tustin represents the use of Tustin discretization method to discretize the observer equation, I is the unit matrix, T s Indicates the system sampling time.

6. The method for controlling a permanent magnet synchronous motor with a single current sensor based on a discrete current state observer according to claim 3, characterized in that: The step S3 adopts a hybrid discrete method to calculate u d (k) and u q (k),ω e (k), i d (k), i q (k) Predict the current at time k+1 and Where: the subscript HY represents the observer equation discretized using the hybrid discretization method, T s Indicates the system sampling time.

7. The method for controlling a permanent magnet synchronous motor with a single current sensor based on a discrete current state observer according to claim 3, characterized in that: In step S3, the matched pole-zero discrete method is used to calculate the value of u d (k) and u q (k),ω e (k), i d (k), i q (k) Predict the current at time k+1 and Where: subscript MPZ represents the observer equation discretized using the matched pole-zero discretization method, T s Represents the system sampling time, and a and b are intermediate parameters.

8. The method for controlling a permanent magnet synchronous motor with a single current sensor based on a discrete current state observer according to claim 1, characterized in that: The step S4 specifically comprises: e (k+1), and Perform inverse Park transform and inverse Clark transform to obtain the current in the abc coordinate system; Where: i α and i β Represents the current component in the α-β coordinate system.

9. The method for controlling a permanent magnet synchronous motor with a single current sensor based on a discrete current state observer according to claim 1, characterized in that: The step S7 specifically comprises: e (k+1),u d (k+1) and u q (k+1) Perform inverse Park transform to get u α (k+1) and u β (k+1); 10. A single current sensor control system for a permanent magnet synchronous motor based on a discrete current state observer, characterized in that: It includes a processor, a memory and a computer program stored in the memory. When the processor executes the computer program, it specifically executes the steps in the permanent magnet synchronous motor single current sensor control method based on discrete current state observer as described in any one of claims 1 to 9.

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