Current control device and method for permanent magnet synchronous motor

Abstract

The invention discloses a permanent magnet synchronous motor current control device and method. The current control device comprises a feedback control module, a feed-forward compensation module and an optimal amplitude limiting module. The feedback control module comprises an adder, a current instruction filter, a proportional-integral controller and an anti-saturation controller. And the feed-forward compensation module is used for compensating counter electromotive forces of a direct axis and a quadrature axis of the motor to improve the current response performance. And the optimal amplitude limiting module calculates an optimal quadrature-axis voltage amplitude limiting value according to the current rotor position and performs amplitude limiting, and calculates a voltage saturation value for resisting saturation at the same time. According to the current control device, a current loop optimal amplitude limiting and anti-saturation method is provided, the problems that a proportional-integral current loop control structure is long in adjustment time, integral is easy to saturate, and stability is reduced after amplitude limiting are solved, and the stability and the optimal control performance of a control system can be guaranteed under different working conditions.

Description

Technical Field

[0001] The present application relates to the technical field of servo system control, and in particular to a permanent magnet synchronous motor current control device and method. Background Art

[0002] Motor servo systems are core components in modern automation equipment and are widely used in industrial production, robotics, aerospace, medical equipment and other fields.

[0003] As technology continues to advance, motor servo systems are also continuing to develop to meet increasingly complex industrial needs.

[0004] Permanent magnet synchronous motor (PMSM) has gradually been widely used in home appliances, automobile drives and other fields due to its advantages such as simple structure, high power density and low operating cost.

[0005] Currently, the current loop control of the permanent magnet synchronous motor is usually achieved by controlling the stator DC voltage and the stator AC voltage.

[0006] However, in actual operation, the voltage output is often in a saturated state. At this time, the use of a linear controller with an integrator is prone to integral saturation problems, and the traditional voltage overmodulation limiting algorithm is too simple and does not fully consider the characteristics of the motor current loop model, resulting in a decrease in the control performance and stability of the current loop in the saturated state. In order to solve these problems, it is urgent to explore more advanced current control structures.

[0007] A complete current control structure should have the following characteristics: good stability and tracking capability, strong anti-interference performance, the ability to resist current model parameter fluctuations, and include limiting and anti-saturation algorithms to ensure that excellent control performance can be maintained when the voltage output is saturated. Summary of the invention

[0008] The present application provides a permanent magnet synchronous motor current control device and method to solve the problems of long adjustment time, easy saturation of integral and decreased stability after limiting of the proportional-integral current loop control structure, and can ensure the stability of the control system and the best control performance under different working conditions.

[0009] In a first aspect, the present application provides a permanent magnet synchronous motor current control device, which is used to be connected to a motor object, and the current control device includes: a feedback control module, a feedforward compensation module and an optimal limiting module.

[0010] The feedback control module includes a direct-axis current command filter, a quadrature-axis current command filter, a direct-axis first adder, a quadrature-axis first adder, a direct-axis proportional-integral controller, a quadrature-axis proportional-integral controller, a direct-axis second adder, a quadrature-axis second adder, a direct-axis anti-saturation controller, and a quadrature-axis anti-saturation controller, and the proportional-integral controller includes an adder, a proportional controller, and an integral controller.

[0011] The output end of the AC and DC axis current command filter is connected to the input end of the first AC and DC axis adder, the AC and DC proportional-integral controller is connected between the output end of the first AC and DC axis adder and the input end of the second AC and DC axis adder, the output end of the second AC and DC axis adder is connected to the input end of the optimal amplitude limiting module, and the AC and DC axis anti-saturation controller is connected to the input end of the adder in the AC and DC axis proportional-integral controller;

[0012] The feedforward compensation module is connected to the feedback control module and the motor object, and is used to compensate for the back electromotive force of the quadrature and direct axes;

[0013] The optimal limiting module is connected to the feedback control module and the motor object, and is used to calculate the optimal quadrature-axis voltage limiting value according to the current rotor position and perform limiting, and at the same time calculate the voltage saturation value for controller anti-saturation.

[0014] In combination with the first aspect, in some implementations of the first aspect, the input parameters of the optimal limiting module include a quadrature-axis voltage command, a direct-axis voltage command, and a current position of the rotor, and the output parameters include a quadrature-axis voltage command after limiting, a direct-axis voltage command after limiting, a direct-axis voltage saturation value, and a quadrature-axis voltage saturation value. The quadrature-axis voltage command after limiting and the direct-axis voltage command after limiting are used to drive the motor object to operate, and the direct-axis voltage saturation value and the quadrature-axis voltage saturation value are used as inputs of the anti-saturation controller. The optimal limiting module first calculates a direct-axis voltage comparison value according to the current position of the rotor, and then determines a quadrature-axis voltage interval according to the quadrature-axis voltage command, the direct-axis voltage command, the current position of the rotor, and the direct-axis voltage comparison value, and then calculates an optimal quadrature-axis voltage limiting value according to the quadrature-axis voltage interval, the quadrature-axis voltage command, the direct-axis voltage command, and the current position of the rotor, and finally performs a limiting operation to output the quadrature-axis voltage command after limiting, the direct-axis voltage command after limiting, the direct-axis voltage saturation value, and the quadrature-axis voltage saturation value.

[0015] In combination with the first aspect, in some implementations of the first aspect, the first set of equations is:

[0016] θ 1 =θ%(π / 3)

[0017] OL 1 =(2 / 3)U dc cos(π / 3-θ1 )

[0018] OL 2 =(2 / 3)U dc cos(2π / 3-θ 1 )

[0019] OL 3 =(2 / 3)U dc cos(π / 3+θ 1 )

[0020] OL 4 =(2 / 3)U dc cos(θ 1 )

[0021] Among them, U dc is the bus voltage value of the motor object, θ is the current position of the motor rotor, θ 1 is the remainder of θ divided by π / 3, OL 1 ,OL 2 ,OL 3 ,OL 4 The four cases are represented as the direct-axis voltage comparison value OL. The specific judgment method is as follows: when the direct-axis voltage command and the quadrature-axis voltage command have the same sign, that is, the multiplication is positive, it is judged that θ 1 Is it less than π / 6? If so, OL=OL 1 ,

[0022] Otherwise OL=OL 2 When the direct-axis voltage command and the quadrature-axis voltage command have opposite signs, that is, their multiplication is negative, the θ 1 Is it less than π / 6? If so, OL=OL 3 , otherwise OL=OL 4 .

[0023] In combination with the first aspect, in some implementations of the first aspect, the second set of equations is:

[0024] OD=|U DREF |

[0025]

[0026] DQ 1 =(OA 1 -OD)U dc / sin(π / 3+θ 2 )

[0027]

[0028] DQ 2 =BD 2 / cos(θ2 )

[0029]

[0030] DQ 3 =BD 3 / cos(π / 3-θ 2 )

[0031] OA 4 =OD / cos(π / 3-θ 2 )

[0032] AD 4 =OA 4 cos(π / 6+θ 2 )

[0033] AQ 4 =(OA 4 +(2 / 3)U dc )sin(π / 3) / sin(π / 2-θ 2 )

[0034] DQ 4 =AQ 4 -AD 4

[0035] Where OD is the direct axis voltage command U DREF The absolute value of θ 2 is θ 1 The mapping value of θ is determined as follows: 1 Is it less than π / 6? If so, then θ 2 =θ 1 , otherwise θ 2 =π / 3-θ 1 .

[0036] DQ 1 , DQ 2 , DQ 3 , DQ 4 The four cases are represented as the optimal quadrature-axis voltage limit value DQ. The specific judgment method is as follows: when the direct-axis voltage command and the quadrature-axis voltage command have the same sign, that is, the multiplication is positive, it is judged whether OD is greater than OL. If OD is greater than OL, it is judged that θ 1 Is it less than π / 6? If so, DQ = DQ 1 , otherwise DQ=DQ 3 , if OD is less than OL, judge θ 1 Is it less than π / 6? If so, DQ = DQ 2 , otherwise DQ=DQ 4When the direct-axis voltage command and the quadrature-axis voltage command have opposite signs, that is, the multiplication is negative, determine whether OD is greater than OL. If OD is greater than OL, determine θ 1 Is it less than π / 6? If so, DQ = DQ 3 , otherwise DQ=DQ 1 , if OD is less than OL, judge θ 1 Is it less than π / 6? If so, DQ = DQ 2 , otherwise DQ=DQ 4 After determining the situation, only the calculations related to the current DQ situation are performed, and irrelevant variables are not calculated.

[0037] In combination with the first aspect, in some implementations of the first aspect, the third program group is:

[0038]

[0039] U DAW =U D -U DREF

[0040] U QAW =U Q -U QERF

[0041] Among them U DREF is the direct axis voltage command, U QREF is the quadrature axis voltage command, U D is the direct axis voltage command after limiting, U Q is the quadrature axis voltage command after limiting, DQ is the optimal quadrature axis voltage limiting value, U DAW is the direct axis voltage saturation value, U QAW is the quadrature axis voltage saturation value.

[0042] In combination with the first aspect, in some implementations of the first aspect, the feedforward compensation algorithm obtains the flux linkage, electrical angular velocity, direct-axis inductance, quadrature-axis inductance, direct-axis current, and quadrature-axis current of the motor, and is used to calculate the back electromotive force values ​​of the direct axis and the quadrature axis. The feedback control module is used to generate a quadrature-axis control voltage according to a quadrature-axis current instruction, and to generate a direct-axis control voltage according to a direct-axis current instruction, and the quadrature-axis control voltage is output to the quadrature-axis second adder, and the direct-axis control voltage is output to the direct-axis second adder.

[0043] In combination with the first aspect, in some implementations of the first aspect, the fourth set of equations is:

[0044] U DE =-wL Q I Q

[0045] U QE =w(ψF L Q I Q )

[0046] Where w is the electrical angular velocity, L Q is the quadrature-axis inductance, I Q is the quadrature axis current, L D is the direct-axis inductance, I D is the direct axis current, ψ F is the magnetic flux, U DE is the direct-axis back electromotive force, U QE is the quadrature axis back electromotive force. DE Output to the second direct axis adder, U QE Output to the second quadrature axis adder.

[0047] In combination with the first aspect, in some implementations of the first aspect, the fifth set of equations is:

[0048]

[0049] Among them C F1 is the quadrature axis current command filter, C F2 is the direct-axis current command filter, C F1 With C F2 are all second-order transfer functions, where N Q1 、N Q2 、N Q3 is the numerator coefficient of the quadrature axis current command filter, M Q1 、M Q2 、M Q3 is the denominator coefficient of the quadrature axis current command filter, N D1 、N D2 、N D3 is the numerator coefficient of the direct-axis current command filter, M D1 、M D2 、M D3 is the denominator coefficient of the direct-axis current command filter, C PI1 is the cross-axis proportional-integral controller, K P1 is the quadrature-axis proportional gain, K I1 is the quadrature axis integral gain, C PI2 is a direct-axis proportional-integral controller, K P2 is the direct axis proportional gain, K I2 is the direct axis integral gain, C AW1 is the quadrature axis anti-windup controller, K AW1 is the quadrature axis anti-saturation gain, τ Q1 , τ Q2 is the cross-axis anti-saturation coefficient, K AW2 is the direct axis anti-saturation gain, τ D1 , τ D2 is the direct axis anti-saturation coefficient.

[0050] In combination with the first aspect, in certain implementations of the first aspect, the current control device generates a limited quadrature-axis voltage command and a limited direct-axis voltage command based on the input quadrature-axis current command and the direct-axis current command, and the voltage command is used to drive the motor to operate.

[0051] In a second aspect, the present application provides a servo system, which includes a motor object and a current control device as described in any one of the above items, wherein the current control device is used to control the operation of the motor object.

[0052] In a third aspect, the present application provides a permanent magnet synchronous motor current control method, the current control method being applied to the current control device as described in any one of the above, or the servo system as described above, the current control method comprising:

[0053] A feedback control algorithm outputs a quadrature-axis control voltage and a direct-axis control voltage according to a quadrature-axis current command, a direct-axis current command and the quadrature-axis current and the direct-axis current of the motor;

[0054] A feedforward compensation algorithm outputs a direct-axis back electromotive force and a quadrature-axis back electromotive force according to the motor flux, electrical angular velocity, direct-axis inductance, quadrature-axis inductance, direct-axis current, and quadrature-axis current;

[0055] An optimal limiting algorithm calculates an optimal quadrature-axis voltage limiting value according to the quadrature-axis voltage command and the direct-axis voltage command obtained by adding the outputs of the feedback control algorithm and the feedforward compensation algorithm to perform limiting operation, and outputs a quadrature-axis voltage command after limiting, a direct-axis voltage command after limiting, a direct-axis voltage saturation value, and a quadrature-axis voltage saturation value;

[0056] In conjunction with the third aspect, in some implementations of the third aspect, the optimal clipping algorithm includes:

[0057] Calculating a direct-axis voltage comparison value according to the current position of the rotor;

[0058] Determine the quadrature-axis voltage interval according to the quadrature-axis voltage command, the direct-axis voltage command, the current position of the rotor and the direct-axis voltage comparison value, and then calculate the optimal quadrature-axis voltage limit value according to the quadrature-axis voltage interval, the quadrature-axis voltage command, the direct-axis voltage command and the current position of the rotor;

[0059] Perform limiting operation and output the quadrature-axis voltage command after limiting, the direct-axis voltage command after limiting, the direct-axis voltage saturation value, and the quadrature-axis voltage saturation value.

[0060] In conjunction with the third aspect, in some implementations of the third aspect, the first set of equations is:

[0061] θ 1 =θ%(π / 3)

[0062] OL 1 =(2 / 3)U dc cos(π / 3-θ 1 )

[0063] OL 2 =(2 / 3)U dc cos(2π / 3-θ 1 )

[0064] OL 3 =(2 / 3)U dc cos(π / 3+θ 1 )

[0065] OL 4 =(2 / 3)U dc cos(θ 1 )

[0066] Among them, U dc is the bus voltage value of the motor object, θ is the current position of the motor rotor, θ 1 is the remainder of θ divided by π / 3, OL 1 ,OL 2 ,OL 3 ,OL 4 The four cases are represented as the direct-axis voltage comparison value OL. The specific judgment method is as follows: when the direct-axis voltage command and the quadrature-axis voltage command have the same sign, that is, the multiplication is positive, it is judged that θ 1 Is it less than π / 6? If so, OL=OL 1 , otherwise OL=OL 2 When the direct-axis voltage command and the quadrature-axis voltage command have opposite signs, that is, their multiplication is negative, the θ 1 Is it less than π / 6? If so, OL=OL 3 , otherwise OL=OL 4 .

[0067] In conjunction with the third aspect, in some implementations of the third aspect, the second set of equations is:

[0068] OD=|U DREF |

[0069]

[0070] DQ 1 =(OA 1 -OD)U dc / sin(π / 3+θ 2 )

[0071]

[0072] DQ2 =BD 2 / cos(θ 2 )

[0073]

[0074] DQ 3 =BD 3 / cos(π / 3-θ 2 )

[0075] OA 4 =OD / cos(π / 3-θ 2 )

[0076] AD 4 =OA 4 cos(π / 6+θ 2 )

[0077] AQ 4 =(OA 4 +(2 / 3)U dc )sin(π / 3) / sin(π / 2-θ 2 )

[0078] DQ 4 =AQ 4 -AD 4

[0079] Where OD is the direct axis voltage command U DREF The absolute value of θ 2 is θ 1 The mapping value of θ is determined as follows: 1 Is it less than π / 6? If so, then θ 2 =θ 1 , otherwise θ 2 =π / 3-θ 1 .

[0080] DQ 1 , DQ 2 , DQ 3 , DQ 4 The four cases are represented as the optimal quadrature-axis voltage limit value DQ. The specific judgment method is as follows: when the direct-axis voltage command and the quadrature-axis voltage command have the same sign, that is, the multiplication is positive, it is judged whether OD is greater than OL. If OD is greater than OL, it is judged that θ 1 Is it less than π / 6? If so, DQ = DQ 1 , otherwise DQ=DQ 3 , if OD is less than OL, judge θ 1 Is it less than π / 6? If so, DQ = DQ 2 , otherwise DQ=DQ 4When the direct-axis voltage command and the quadrature-axis voltage command have opposite signs, that is, the multiplication is negative, determine whether OD is greater than OL. If OD is greater than OL, determine θ 1 Is it less than π / 6? If so, DQ = DQ 3 , otherwise DQ=DQ 1 , if OD is less than OL, judge θ 1 Is it less than π / 6? If so, DQ = DQ 2 , otherwise DQ=DQ 4 After determining the situation, only the calculations related to the current DQ situation are performed, and irrelevant variables are not calculated.

[0081] In conjunction with the third aspect, in some implementations of the third aspect, the third program group is:

[0082]

[0083] U DAW =U D -U DREF

[0084] U QAW =U Q -U QREF

[0085] Among them U dc is the bus voltage of the motor object, U DREF is the direct axis voltage command, U QREF is the quadrature axis voltage command, U D is the direct axis voltage command after limiting, U Q is the quadrature axis voltage command after limiting, DQ is the optimal quadrature axis voltage limiting value, U DAW is the direct axis voltage saturation value, U QAW is the quadrature axis voltage saturation value.

[0086] In combination with the third aspect, in some implementations of the third aspect, the feedforward compensation algorithm obtains the flux, electrical angular velocity, direct-axis inductance, quadrature-axis inductance, direct-axis current, and quadrature-axis current of the motor to calculate the back electromotive force values ​​of the direct axis and the quadrature axis, and the back electromotive force calculation formula is:

[0087] U DE =-wL Q I Q

[0088] U QE =w(ψ F L Q I Q )

[0089] Where w is the electrical angular velocity, L Q is the quadrature-axis inductance, IQ is the quadrature axis current, L D is the direct-axis inductance, I D is the direct axis current, ψ F is the magnetic flux, U DE is the direct-axis back electromotive force, U QE is the quadrature-axis back electromotive force.

[0090] In combination with the third aspect, in some implementations of the third aspect, the feedback control module is used to generate a quadrature-axis control voltage according to a quadrature-axis current instruction and to generate a direct-axis control voltage according to a direct-axis current instruction, and a transfer function expression related to the feedback control module is:

[0091]

[0092] Among them C F1 is the quadrature axis current command filter, C F2 is the direct-axis current command filter, C F1 With C F2 are all second-order transfer functions, where N Q1 、N Q2 、N Q3 is the numerator coefficient of the quadrature axis current command filter, M Q1 、M Q2 、M Q3 is the denominator coefficient of the quadrature axis current command filter, N D1 、N D2 、N D3 is the numerator coefficient of the direct-axis current command filter, M D1 、M D2 、M D3 is the denominator coefficient of the direct-axis current command filter, C PI1 is the cross-axis proportional-integral controller, K P1 is the quadrature-axis proportional gain, K I1 is the quadrature axis integral gain, C PI2 is a direct-axis proportional-integral controller, K P2 is the direct axis proportional gain, K I2 is the direct axis integral gain, C AW1 is the quadrature axis anti-windup controller, K AW1 is the quadrature axis anti-saturation gain, τ Q1 , τ Q2 is the cross-axis anti-saturation coefficient, K AW2 is the direct axis anti-saturation gain, τ D1 , τ D2 is the direct axis anti-saturation coefficient.

[0093] In a fourth aspect, the present application provides a permanent magnet synchronous motor current control device, which includes a memory and a processor, the memory is used to store program instructions, and the processor is used to call the program instructions to execute any current control method described above.

[0094] In a fifth aspect, the present application provides a computer-readable storage medium, wherein the computer-readable storage medium is used to store instructions, and when the instructions are executed, any current control method described above is implemented.

[0095] The permanent magnet synchronous motor current control device, method, servo system and computer-readable storage medium provided by the present invention introduce a feedback control module, a feedforward compensation module and an optimal limiting module. The feedback control module includes an adder, a current command filter, a proportional integral controller and an anti-saturation controller. The feedforward compensation module is used to compensate for the back electromotive force of the motor direct axis and the quadrature axis to improve the current response performance. The optimal limiting module calculates the optimal quadrature axis voltage limiting value according to the current rotor position and performs limiting, and calculates the voltage saturation value for anti-saturation. The current control device proposes an optimal current loop limiting and anti-saturation method, which solves the problems of long adjustment time, easy saturation of integral and decreased stability after limiting of the proportional integral current loop control structure, and can ensure the stability of the control system and the best control performance under different working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0096] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0097] Figure 1 is a structural block diagram of a servo system provided in an embodiment of the present application;

[0098] Figure 2 is a schematic diagram of the structure of a servo system provided in an embodiment of the present application;

[0099] Figure 3 is a flow chart of a current control method provided in an embodiment of the present application;

[0100] Figure 4 is a structural block diagram of a current control device provided in an embodiment of the present application;

[0101] Figure 5 It is a step response test result diagram of a permanent magnet synchronous motor under the control of a typical proportional integral control structure provided by the comparative example and under the control of a current control device provided by an embodiment of the present application;

[0102] Figure 6 It is a full-power operation test result diagram (quadrature-axis current) of a permanent magnet synchronous motor under the control of a typical proportional-integral control structure provided by the comparative example and under the control of a current control device provided by an embodiment of the present application;

[0103] Figure 7 It is a full-power operation test result diagram (direct-axis current) of a permanent magnet synchronous motor under the control of a typical proportional-integral control structure provided by the comparative example and under the control of a current control device provided by an embodiment of the present application;

[0104] The following specific implementation methods will further illustrate the present application in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0105] To facilitate understanding of the present application, the contents of the present application will be described more comprehensively below in conjunction with relevant drawings, including an introduction to the application ideas and typical embodiments.

[0106] Please also read Figure 1 and Figure 2 , Figure 1 is a structural block diagram of a servo system 1000 provided in an embodiment of the present application; Figure 2 It is a schematic diagram of the structure of the servo system 1000 provided in an embodiment of the present application.

[0107] The embodiment of the present application provides a servo system 1000. The servo system 1000 includes a current control device 100 and a motor object 104. The current control device 100 is connected to the motor object 104 and is used to control the operation of the motor object 104.

[0108] The current control device 100 includes a feedback control module 101 , a feedforward compensation module 102 and an optimal amplitude limiting module 103 .

[0109] The feedback control module includes a direct-axis current command filter 1011, a quadrature-axis current command filter 1012, a direct-axis first adder 1041, a quadrature-axis first adder 1042, a direct-axis proportional-integral controller 1021, a quadrature-axis proportional-integral controller 1022, a direct-axis second adder 1051, a quadrature-axis second adder 1052, a direct-axis anti-saturation controller 1031, a quadrature-axis anti-saturation controller 1032, and the proportional-integral controllers 1021 and 1022 include adders, proportional controllers, and integral controllers.

[0110] The output ends of the quadrature and direct axis current command filters 1012 and 1011 are connected to the input ends of the quadrature and direct axis first adders 1042 and 1041;

[0111] The AC and DC proportional-integral controllers 1022 and 1021 are connected between the output ends of the AC and DC first adders 1042 and 1041 and the input ends of the AC and DC second adders 1052 and 1051;

[0112] The output ends of the second adders 1052 and 1051 of the quadrature and direct axes are connected to the input end of the optimal amplitude limiting module 103, and the quadrature and direct axis anti-saturation controllers 1032 and 1031 are connected to the input ends of the adders in the quadrature and direct axis proportional-integral controllers 1022 and 1021;

[0113] The feedforward compensation module 102 is connected to the feedback control module 101 and the motor object 104 and is used to compensate the back electromotive force of the quadrature and direct axes;

[0114] The AC and DC axis back electromotive force are sent to the AC and DC axis second adders 1052 and 1051;

[0115] The optimal limiting module 103 is connected to the feedback control module 101 and the motor object 104, and is used to calculate the optimal quadrature-axis voltage limiting value according to the current rotor position and perform limiting, and obtain the quadrature-axis voltage instruction after limiting, the direct-axis voltage instruction after limiting, the quadrature-axis voltage saturation value, and the direct-axis voltage saturation value. The voltage instruction after limiting is sent to the motor object 104 to drive the motor to operate, and the voltage saturation value is sent to the input end of the quadrature-axis and direct-axis anti-saturation controllers 1032 and 1031.

[0116] For the servo system 1000, its motor object 104 can usually be characterized by resistance, inductance, time delay, and flux linkage. For the surface-mounted permanent magnet synchronous motor in this embodiment, after the back electromotive force is compensated by the feedforward compensation module, the quadrature-axis current model and the direct-axis current model of the motor object 104 can be considered the same, and its transfer function can be expressed as:

[0117]

[0118] Wherein, L represents the quadrature and direct axis inductance of the motor object 104, and τ represents the delay parameter of the motor object 104. In this embodiment, the specific values ​​of the motor object characteristic parameters are L=3mH, R=1.35ohm, τ=3.11*10 -5 s.

[0119] Step S1, feedback control algorithm, outputs quadrature-axis control voltage and direct-axis control voltage according to quadrature-axis current command, direct-axis current command and the quadrature-axis current and direct-axis current of the motor.

[0120] The transfer function expression of the feedback control module is:

[0121]

[0122] Among them C F1 is the quadrature axis current command filter, C F2 is the direct-axis current command filter, C F1 With C F2 are all second-order transfer functions, where N Q1 、N Q2 、N Q3 is the numerator coefficient of the quadrature axis current command filter, M Q1 、M Q2 、M Q3 is the denominator coefficient of the quadrature axis current command filter, N D1 、N D2 、N D3 is the numerator coefficient of the direct-axis current command filter, M D1 、M D2 、M D3 is the denominator coefficient of the direct-axis current command filter, C PI1 is the cross-axis proportional-integral controller, K P1 is the quadrature-axis proportional gain, K I1 is the quadrature axis integral gain, C PI2 is a direct-axis proportional-integral controller, K P2 is the direct axis proportional gain, K I2 is the direct axis integral gain, C AW1 is the quadrature axis anti-windup controller, K AW1 is the quadrature axis anti-saturation gain, τ Q1 , τ Q2 is the cross-axis anti-saturation coefficient, K AW2 is the direct axis anti-saturation gain, τ D1 , τ D2 is the direct axis anti-saturation coefficient.

[0123] In this embodiment, the specific parameters of the feedback control module related transfer function are:

[0124]

[0125] C AW1 =C AW2 =1.05

[0126] The current command filter C F1 With proportional-integral controller C PI1 The two-degree-of-freedom control structure formed by the current command filter and the proportional-integral controller has better anti-disturbance capability while ensuring the same tracking performance compared to the traditional proportional-integral controller. AW1 , C AW2Set to DC gain, the anti-interference effect can be enhanced by increasing the gain strength, but too high DC gain will cause the control performance to deteriorate.

[0127] The current command passes through the current command filter C F1 , C F2 The output of the motor object is subtracted from the quadrature-axis current feedback value of the motor object and the direct-axis motor feedback value to obtain a current error value. The current error value is obtained by a proportional-integral controller C PI1 , C PI2 The quadrature axis control voltage and the direct axis control voltage are calculated. The voltage saturation value output by the optimal limiting module is controlled by the anti-saturation controller C AW1 , C AW2 The integral anti-saturation value is obtained as the proportional integral controller C PI1 , C PI2 Input value to the adder.

[0128] Step S2, feedforward compensation algorithm, outputting direct-axis back electromotive force and quadrature-axis back electromotive force according to the motor flux, electrical angular velocity, direct-axis inductance, quadrature-axis inductance, direct-axis current, and quadrature-axis current. The back electromotive force calculation formula is:

[0129] U DE =-wL Q I Q

[0130] U QE =w(ψ F L Q I Q )

[0131] Where w is the electrical angular velocity, L Q is the quadrature-axis inductance, I Q is the quadrature axis current, L D is the direct-axis inductance, I D is the direct axis current, ψ F is the magnetic flux, U DE is the direct-axis back electromotive force, U QE is the cross-axis back electromotive force. In this embodiment, the flux linkage value ψ F =0.0441

[0132] In this embodiment, the specific expression of the back electromotive force calculation formula is:

[0133] U DE =-3wI Q / 1000

[0134] U QE =w(0.1323I Q ) / 1000

[0135] Direct axis back electromotive force UDE As the input value of the second direct-axis adder, the quadrature-axis back electromotive force U DE As the input value of the second adder of the quadrature axis.

[0136] Step S3, the AC and DC axis control voltages are added to the AC and DC axis back electromotive forces through the AC and DC axis second adders to obtain the AC and DC axis voltage instructions, and the voltage instructions are used as inputs for the optimal limiting algorithm.

[0137] Step S4, the optimal limiting algorithm calculates the optimal quadrature-axis voltage limiting value according to the quadrature-axis voltage command and the direct-axis voltage command obtained by adding the outputs of the feedback control algorithm and the feedforward compensation algorithm, and performs limiting operation, and outputs the quadrature-axis voltage command after limiting, the direct-axis voltage command after limiting, the direct-axis voltage saturation value, and the quadrature-axis voltage saturation value.

[0138] Among them, the first set of equations can be configured as:

[0139] θ 1 =θ%(π / 3)

[0140] OL 1 =(2 / 3)U dc cos(π / 3-θ 1 )

[0141] OL 2 =(2 / 3)U dc cos(2π / 3-θ 1 )

[0142] OL 3 =(2 / 3)U dc cos(π / 3+θ 1 )

[0143] OL 4 =(2 / 3)U dc cos(θ 1 )

[0144] Among them, U dc is the bus voltage value of the motor object. In this embodiment, the bus voltage value of the motor object U dc =320V, θ is the current position of the motor rotor, θ 1 is the remainder of θ divided by π / 3, OL 1 ,OL 2 ,OL 3 ,OL 4 The four cases are represented as the direct-axis voltage comparison value OL. The specific judgment method is as follows: when the direct-axis voltage command and the quadrature-axis voltage command have the same sign, that is, the multiplication is positive, it is judged that θ 1 Is it less than π / 6? If so, OL=OL 1, otherwise OL=OL 2 When the direct-axis voltage command and the quadrature-axis voltage command have opposite signs, that is, their multiplication is negative, the θ 1 Is it less than π / 6? If so, OL=OL 3 , otherwise OL=OL 4 .

[0145] In this embodiment, the second set of equations can be configured as:

[0146] OD=|U DREF |

[0147] OA 1 =184.75 / sin(π / 3+θ 2 )

[0148] DQ 1 =(OA 1 -OD)320 / sin(π / 3+θ 2 )

[0149] BD 2 =184.75-ODsin(θ 2 )

[0150] DQ 2 =BD 2 / cos(θ 2 )

[0151] BD 3 =184.75-ODsin(π / 3-θ 2 )

[0152] DQ 3 =BD 3 / cos(π / 3-θ 2 )

[0153] OA 4 =OD / cos(π / 3-θ 2 )

[0154] AD 4 =OA 4 cos(π / 6+θ 2 )

[0155] AQ 4 =(OA 4 +213.33)sin(π / 3) / sin(π / 2-θ 2 )

[0156] DQ 4 =AQ 4 -AD 4

[0157] Where OD is the direct axis voltage command U DREF The absolute value of θ 2 is θ 1 The mapping value of θ is determined as follows: 1 Is it less than π / 6? If so, then θ 2 =θ 1 , otherwise θ 2 =π / 3-θ 1 .

[0158] DQ 1 , DQ 2 , DQ 3 , DQ 4 The four cases are represented as the optimal quadrature-axis voltage limit value DQ. The specific judgment method is as follows: when the direct-axis voltage command and the quadrature-axis voltage command have the same sign, that is, the multiplication is positive, it is judged whether OD is greater than OL. If OD is greater than OL, it is judged that θ 1 Is it less than π / 6? If so, DQ = DQ 1 , otherwise DQ=DQ 3 , if OD is less than OL, judge θ 1 Is it less than π / 6? If so, DQ = DQ 2 , otherwise DQ=DQ 4 When the direct-axis voltage command and the quadrature-axis voltage command have opposite signs, that is, the multiplication is negative, determine whether OD is greater than OL. If OD is greater than OL, determine θ 1 Is it less than π / 6? If so, DQ = DQ 3 , otherwise DQ=DQ 1 , if OD is less than OL, judge θ 1 Is it less than π / 6? If so, DQ = DQ 2 , otherwise DQ=DQ 4 After determining the situation, only the calculations related to the current DQ situation are performed, and irrelevant variables are not calculated.

[0159] In this embodiment, the third process group can be configured as:

[0160]

[0161] U DAW =U D -U DREF

[0162] U QAW =U Q -U QREF

[0163] Among them U dc is the bus voltage of the motor object, U DREFis the direct axis voltage command, U QREF is the quadrature axis voltage command, U D is the direct axis voltage command after limiting, U Q is the quadrature axis voltage command after limiting, DQ is the optimal quadrature axis voltage limiting value, U DAW is the direct axis voltage saturation value, U QAW is the quadrature axis voltage saturation value.

[0164] The clipped quadrature-axis voltage command and the clipped direct-axis voltage command are used to drive the motor object to operate, and the direct-axis voltage saturation value and the quadrature-axis voltage saturation value are used for voltage anti-saturation calculation in the feedback control module.

[0165] See also Figure 4 The embodiment of the present application further provides a current control device 400. The current control device 400 includes a memory 410 and a processor 420. The memory 410 is used to store program instructions, and the processor 420 is used to execute any of the above current control methods by running or executing computer programs and / or modules stored in the memory 410, and calling program instructions to implement the parameter setting function of the parameter self-tuning device 400.

[0166] The memory 410 may mainly include a program storage area and a data storage area, wherein the program storage area may store an operating system, application programs required for multiple functions, etc.; the data storage area may store data created according to the operating system, data generated by the application programs, etc. In addition, the memory 410 may include a high-speed random access memory, and may also include a non-volatile memory, such as a hard disk, a memory, a plug-in hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (Secure Digital, SD) card, a flash card (Flash Card), multiple disk storage devices, flash memory devices, or other volatile solid-state storage devices.

[0167] The processor 420 may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor, etc.

[0168] It should be understood by those skilled in the art that Figure 4 The current control device 400 is only an example and does not constitute a limitation on the parameter self-tuning device 400. The parameter self-tuning device 400 may include Figure 4 More or fewer components as shown, or a combination of certain components, or different components, for example, the parameter self-tuning device 400 may also include a driving circuit module, etc.

[0169] An embodiment of the present application also provides a computer-readable storage medium, which is used to store instructions. When the instructions are executed by a processor, any one of the above parameter self-tuning methods is implemented.

[0170] An embodiment of the present application provides an application of a current control method in a servo system 1000 . Figure 5 The figure shows the step response test results of the typical proportional-proportional-integral control structure provided by the comparison ratio and the current control structure provided by the embodiment of the present application when the inductance of the motor object changes from 3mH to 2.4mH. The dotted line represents the cross-axis current response curve of the permanent magnet synchronous motor under the typical proportional-integral control structure, and the solid line represents the cross-axis current response curve of the permanent magnet synchronous motor under the current control structure provided by the present embodiment. It can be seen that the current response overshoot of the embodiment is smaller, the convergence speed is faster, and the overall control performance is better, that is, the control structure of the embodiment has a stronger ability to resist parameter fluctuations.

[0171] Please also read Figure 6 and Figure 7 , shows the current response test result diagram of the typical proportional-proportional-integral control structure provided by the comparison ratio and the current control structure provided by the embodiment of the present application when the permanent magnet synchronous motor is running at full power, that is, full voltage utilization. The line represents the current response curve of the permanent magnet synchronous motor under the typical proportional-integral control structure, and the solid line represents the current response curve of the permanent magnet synchronous motor under the current control structure provided by this embodiment. Figure 6 It can be seen that in the case of insufficient total voltage, the quadrature-axis current value in the embodiment decreases at a smaller rate and does not produce the current mutation in the comparative example. Figure 7 It can be seen that when the total voltage is insufficient, the direct-axis current fluctuation in the embodiment is much smaller than that in the comparative example. The direct-axis current fluctuation will affect the excitation flux of the permanent magnet synchronous motor, causing changes in motor-related parameters. Excessive direct-axis current will lead to magnetic circuit saturation, greatly reduce the direct-axis inductance, and cause the direct-axis current to be out of control. It can be seen that the direct-axis current fluctuation range in the embodiment is controlled within 1 ampere, and the direct-axis current convergence speed is also significantly faster than the current convergence speed in the comparative example.

[0172] The current control device described in this embodiment solves the problems of long adjustment time, easy saturation of integral and decreased stability after limiting of the proportional-integral current loop control structure based on the optimal limiting and anti-saturation method of the current loop, and can ensure the stability of the control system and the best control performance under different working conditions.

[0173] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0174] It should be noted that, for the above-mentioned method embodiments, for the sake of simplicity, they are all expressed as a series of action combinations, but those skilled in the art should be aware that this application is not limited by the order of the actions described, because according to this application, some steps may be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by this application.

[0175] In the several embodiments provided in the present application, it should be understood that the disclosed device can be implemented in other ways. For example, the device embodiments described above are only schematic. When the above-mentioned parameter self-tuning method is implemented in the form of a software function unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on such an understanding, the technical solution of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including several instructions to enable a computer device (which can be a personal computer, a server or a network device, etc., specifically a processor in a computer device) to perform all or part of the steps of the above-mentioned calibration method in each embodiment of the present application. Among them, the aforementioned storage medium may include: U disk, mobile hard disk, disk, CD, read-only memory (English: Read-Only Memory, abbreviated: ROM) or random access memory (English: Random Access Memory, abbreviated: RAM) and other media that can store program codes.

[0176] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in the present application, and these modifications or replacements should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A permanent magnet synchronous motor current control device, used to connect with a motor object, characterized in that: include: Feedback control module, feedforward compensation module and optimal limiting module; The feedback control module includes a direct-axis current command filter, a quadrature-axis current command filter, a direct-axis first adder, a quadrature-axis first adder, a direct-axis proportional-integral controller, a quadrature-axis proportional-integral controller, a direct-axis second adder, a quadrature-axis second adder, a direct-axis anti-saturation controller, and a quadrature-axis anti-saturation controller, and the proportional-integral controller includes an adder, a proportional controller, and an integral controller; The output end of the quadrature and direct axis current command filter is connected to the input end of the quadrature and direct axis first adder; The AC / DC proportional-integral controller is connected between the output end of the first AC / DC adder and the input end of the second AC / DC adder; The output end of the second adder of the quadrature and direct axes is connected to the input end of the optimal amplitude limiting module; The quadrature and direct axis anti-saturation controller is connected to the input end of the adder in the quadrature and direct axis proportional-integral controller; The feedforward compensation module is connected to the feedback control module and the motor object, and is used to compensate for the back electromotive force of the quadrature and direct axes; The optimal limiting module is connected to the feedback control module and the motor object, and is used to calculate the optimal quadrature-axis voltage limiting value according to the current rotor position and perform limiting, and at the same time calculate the voltage saturation value for controller anti-saturation.

2. The current control device according to claim 1, characterized in that: The input parameters of the optimal limiting module include a quadrature-axis voltage command, a direct-axis voltage command, and a current rotor position; The output parameters of the optimal limiting module include the quadrature-axis voltage command after limiting, the direct-axis voltage command after limiting, the direct-axis voltage saturation value, and the quadrature-axis voltage saturation value. The quadrature-axis voltage command after limiting and the direct-axis voltage command after limiting are used to drive the motor object to operate, and the direct-axis voltage saturation value and the quadrature-axis voltage saturation value are used as the input of the anti-saturation controller.

3. The current control device according to claim 2, characterized in that: The optimal limiting module first calculates the direct-axis voltage comparison value according to the current position of the rotor, then determines the quadrature-axis voltage interval according to the quadrature-axis voltage instruction, the direct-axis voltage instruction, the current position of the rotor and the direct-axis voltage comparison value, and then calculates the optimal quadrature-axis voltage limiting value according to the quadrature-axis voltage interval, the quadrature-axis voltage instruction, the direct-axis voltage instruction and the current position of the rotor, and finally performs limiting operation to output the quadrature-axis voltage instruction after limiting, the direct-axis voltage instruction after limiting and the direct-axis voltage saturation value, and the quadrature-axis voltage saturation value.

4. The current control device according to claim 3, characterized in that: The first set of equations of the optimal limiting module is: θ1=θ%(π / 3) OL1=(2 / 3)U dc cos(π / 3-θ1) OL2=(2 / 3)U dc cos(2π / 3-θ1) OL3=(2 / 3)U dc Cos(π / 3+θ1) OL4=(2 / 3)U dc cos(θ1) in, U dc is the bus voltage value of the motor object; θ is the current position of the motor rotor; θ1 is the remainder of θ divided by π / 3; OL1, OL2, OL3, and OL4 represent four situations of the direct-axis voltage comparison value OL, and the specific situation judgment method is as follows; When the direct-axis voltage command and the quadrature-axis voltage command have the same sign, that is, the multiplication is positive, it is determined whether θ1 is less than π / 6. If so, OL=OL1. Otherwise, OL=OL2. When the direct-axis voltage command and the quadrature-axis voltage command have opposite signs, that is, when their multiplication is negative, it is determined whether θ1 is less than π / 6. If so, OL=OL3; otherwise, OL=OL4.

5. The current control device according to claim 4, characterized in that: The second set of equations of the optimal limiting module is: FROM=|IN DREF | DQ1=(OA1-OD)U dc / sin(π / 3+θ2) DQ2=BD2 / cos(θ2) DQ3=BD3 / cos(π / 3-θ2) OA4=OD / cos(π / 3-θ2) AD4=OA4cos(π / 6+θ2) AQ4=(OA4+(2 / 3)U dc )sin(π / 3) / sin(π / 2-θ2) DQ4=AQ4-AD4 in, OD is the direct axis voltage command U DREF The absolute value of θ2 is the mapping value of θ1. The specific judgment method is as follows: judge whether θ1 is less than π / 6. If so, θ2 = θ1; otherwise, θ2 = π / 3-θ1; DQ1, DQ2, DQ3, and DQ4 represent four situations of the optimal quadrature-axis voltage limit value DQ, and the specific situation judgment method is as follows: When the direct-axis voltage command and the quadrature-axis voltage command have the same sign, that is, the multiplication is positive, it is determined whether OD is greater than OL. If OD is greater than OL, it is determined whether θ1 is less than π / 6. If so, DQ=DQ1, otherwise DQ=DQ3. If OD is less than OL, it is determined whether θ1 is less than π / 6. If so, DQ=DQ2, otherwise DQ=DQ4. When the direct-axis voltage command and the quadrature-axis voltage command have opposite signs, that is, the multiplication is negative, it is determined whether OD is greater than OL. If OD is greater than OL, it is determined whether θ1 is less than π / 6. If so, DQ=DQ3, otherwise DQ=DQ1. If OD is less than OL, it is determined whether θ1 is less than π / 6. If so, DQ=DQ2, otherwise DQ=DQ4. After determining the situation, only the calculations related to the current DQ situation are performed, and irrelevant variables are not calculated.

6. The current control device according to claim 5, characterized in that: The third program group of the optimal limiting module is: IN DAW =U D -IN DREF IN QAW =U Q -IN QREF in, U DREF is the direct axis voltage command; U QREF is the quadrature axis voltage command; U D is the direct axis voltage command after limiting; U O It is the quadrature axis voltage command after limiting; DQ is the optimal quadrature-axis voltage limit value; U DAW is the direct axis voltage saturation value; U QAw is the quadrature axis voltage saturation value.

7. The current control device according to claim 1, characterized in that: The feedforward compensation module obtains the flux, electrical angular velocity, direct-axis inductance, quadrature-axis inductance, direct-axis current and / or quadrature-axis current of the motor to calculate the back electromotive force values ​​of the direct axis and the quadrature axis; the back electromotive force calculation formula is: U DE =-wL Q I Q AT QE =w(ψ F L Q AND Q ) in, w is the electrical angular velocity; L O is the quadrature-axis inductance; I Q is the quadrature axis current; L D is the direct-axis inductance; I D is the direct axis current; ψ F is the magnetic link; U DE is the direct-axis back electromotive force; U QE is the quadrature-axis back electromotive force; U DE Output to the second direct axis adder; U QE Output to the second quadrature axis adder.

8. The current control device according to claim 1, characterized in that: The feedback control module is used to generate a quadrature-axis control voltage according to a quadrature-axis current instruction and to generate a direct-axis control voltage according to a direct-axis current instruction; The quadrature-axis control voltage is output to the quadrature-axis second adder, and the direct-axis control voltage is output to the direct-axis second adder. The transfer function expression of the feedback control module is: in, C F1 It is the quadrature axis current command filter; C F2 is the direct-axis current command filter; C F1 With C F2 All are second-order transfer functions; N Q1 、N Q2 、N Q3 is the numerator coefficient of the quadrature-axis current command filter; M Q1 、M Q2 、M Q3 is the denominator coefficient of the quadrature-axis current command filter; N D1 、N D2 、N D3 is the numerator coefficient of the direct-axis current command filter; M D1 、M D2 、M D3 is the denominator coefficient of the direct-axis current command filter; C PI1 It is a cross-axis proportional-integral controller; K P1 is the cross-axis proportional gain; K I1 is the quadrature axis integral gain; C PI2 It is a direct-axis proportional-integral controller; K P2 is the direct axis proportional gain; K I2 is the direct axis integral gain; C AW1 It is a quadrature axis anti-saturation controller; K AW1 is the cross-axis anti-saturation gain; τ Q1 , T Q2 is the cross-axis anti-saturation coefficient; K AW2 is the direct axis anti-saturation gain; τ D1 , τ D2 is the direct axis anti-saturation coefficient.

9. A current control method, characterized in that: The current control device according to any one of claims 1 to 9 is used to implement the control method, and the specific control method comprises the following steps: Feedback control algorithm steps, outputting quadrature-axis control voltage and direct-axis control voltage according to quadrature-axis current command, direct-axis current command and the quadrature-axis current and direct-axis current of the motor: A feedforward compensation algorithm step, outputting a direct-axis back electromotive force and a quadrature-axis back electromotive force according to the motor flux, electrical angular velocity, direct-axis inductance, quadrature-axis inductance, direct-axis current, and quadrature-axis current; The optimal limiting algorithm step calculates the optimal quadrature-axis voltage limiting value according to the quadrature-axis voltage command and the direct-axis voltage command obtained by adding the outputs of the feedback control algorithm and the feedforward compensation algorithm to perform limiting operation, and outputs the quadrature-axis voltage command after limiting, the direct-axis voltage command after limiting, the direct-axis voltage saturation value, and the quadrature-axis voltage saturation value.

10. The current control method according to claim 9, characterized in that: The optimal clipping algorithm includes: Calculating a direct-axis voltage comparison value according to the current position of the rotor; Determine the quadrature-axis voltage interval according to the quadrature-axis voltage command, the direct-axis voltage command, the current position of the rotor and the direct-axis voltage comparison value, and then calculate the optimal quadrature-axis voltage limit value according to the quadrature-axis voltage interval, the quadrature-axis voltage command, the direct-axis voltage command and the current position of the rotor; Performing a limiting operation, outputting a quadrature-axis voltage command after limiting, a direct-axis voltage command after limiting, a direct-axis voltage saturation value, and a quadrature-axis voltage saturation value; The optimal limiting algorithm steps include the following three sets of equations: The first set of equations is: θ1=θ%(π / 3) OL1=(2 / 3)U dc cos(π / 3-θ1) OL2=(2 / 3)U dc cos(2π / 3-θ1) OL3=(2 / 3)U dc cos(π / 3+θ1) OL4=(2 / 3)U dc cos(θ1) in, U dc is the bus voltage value of the motor object; θ is the current position of the motor rotor; θ1 is the remainder of θ divided by π / 3; OL1, OL2, OL3, and OL4 represent four situations of the direct-axis voltage comparison value OL, and the specific situation judgment method is as follows: When the direct-axis voltage command and the quadrature-axis voltage command have the same sign, that is, the multiplication is positive, it is determined whether θ1 is less than π / 6. If so, OL=OL1, otherwise OL=OL2; When the direct-axis voltage command and the quadrature-axis voltage command have opposite signs, that is, the multiplication is negative, it is determined whether θ1 is less than π / 6. If so, OL=OL3, otherwise OL=OL4; The second set of equations is: FROM=|IN DREF | DQ1=(OA1-OD)U dc / sin(π / 3+θ2) DQ2=BD2 / cos(θ2) DQ3=BD3 / cos(π / 3-θ2) OA4=OD / cos(π / 3-θ2) AD4=OA4cos(π / 6+θ2) AQ4=(OA4+(2 / 3)U dc )sin(π / 3) / sin(π / 2-θ2) DQ4=AQ4-AD4 in, OD is the direct axis voltage command U DREF The absolute value of θ2 is the mapping value of θ1. The specific judgment method is as follows: judge whether θ1 is less than π / 6. If so, θ2 = θ1, otherwise θ2 = π / 3-θ1; DQ1, DQ2, DQ3, and DQ4 represent four situations of the optimal quadrature-axis voltage limit value DQ, and the specific situation judgment method is as follows: When the direct-axis voltage command and the quadrature-axis voltage command have the same sign, that is, the multiplication is positive, it is determined whether OD is greater than OL. If OD is greater than OL, it is determined whether θ1 is less than π / 6. If so, DQ=DQ1, otherwise DQ=DQ3. If OD is less than OL, it is determined whether θ1 is less than π / 6. If so, DQ=DQ2, otherwise DQ=DQ4. When the direct-axis voltage command and the quadrature-axis voltage command have opposite signs, that is, when the multiplication is negative, determine whether OD is greater than OL. If OD is greater than OL, determine whether θ1 is less than π / 6. If so, DQ = DQ3, otherwise DQ = DQ1. If OD is less than OL, determine whether θ1 is less than π / 6. If so, DQ = DQ2, otherwise DQ = DQ4. After determining the situation, only the calculation related to the current DQ situation is performed, and irrelevant variables are not calculated; The third set of equations is: IN DAW =U D -IN DREF IN QAW =U Q -IN QREF in, U DREF is the direct axis voltage command U QREF is the quadrature axis voltage command U D The direct axis voltage command after limiting U O The quadrature axis voltage command after limiting DQ is the optimal quadrature-axis voltage limit value U DAW is the direct axis voltage saturation value U QAW is the quadrature axis voltage saturation value; The feedforward compensation algorithm step obtains the flux, electrical angular velocity, direct-axis inductance, quadrature-axis inductance, direct-axis current, and quadrature-axis current of the motor, which are used to calculate the back electromotive force values ​​of the direct axis and the quadrature axis. The back electromotive force calculation formula is: U DE =-wL Q I Q ; AT QE =w(ψ F L Q AND Q ); in, w is the electrical angular velocity; L O is the quadrature-axis inductance; I Q is the quadrature axis current; L D is the direct-axis inductance; I D is the direct axis current; ψ F is the magnetic link; U DE is the direct-axis back electromotive force; U QE is the quadrature-axis back electromotive force.

Images