A salient pole permanent magnet synchronous motor decoupling control system

Abstract

The application relates to a decoupling control system of a salient pole permanent magnet synchronous motor, wherein the direct-axis inductance of the salient pole permanent magnet synchronous motor is greater than the cross-axis inductance, the limit condition that the direct-axis current i d , the cross-axis current i q and the rotating speed omega r of the motor satisfy is determined, the calculation method of the leading angle alpha of the armature reaction magnetic flux relative to the stator magnetic motive force is determined, and the decoupling control and method of the direct-axis current and the cross-axis current are determined, and the control system comprises a three-phase inverter, a control module, a speed and position detection device and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of permanent magnet synchronous motor control technology, in particular to a salient pole permanent magnet synchronous motor decoupling control system and method with direct-axis inductance greater than quadrature-axis inductance. BACKGROUND

[0002] The salient pole permanent magnet synchronous motor has been widely applied in the fields of aerospace, electric vehicles and hybrid electric vehicles, household appliances, etc. due to its small size, high efficiency, high power density, high inertia ratio, wide speed regulation range, etc.

[0003] In some special application environments, such as vehicle-mounted and airborne application occasions, there are strict requirements on the size and weight of the motor, that is, the motor is required to have a high output power density, and the ideal working state of the motor is a constant power control mode.

[0004] For a long time, people have realized that the reluctance torque generated by the asymmetric structure of the rotor of the salient pole permanent magnet synchronous motor helps to improve the overload capacity of the motor. Moreover, when the salient pole permanent magnet synchronous motor works in the constant power mode, it is impossible to increase the speed by increasing the output voltage of the three-phase inverter, but the direct-axis current of the motor can be adjusted to achieve the purpose of field weakening and speed increasing. However, even for the salient pole permanent magnet synchronous motor, different control effects often occur, and people realize that not all salient pole permanent magnet synchronous motors are suitable for constant power control. SUMMARY

[0005] In view of the deficiencies in the prior art, in order to realize the constant power control of the salient pole permanent magnet synchronous motor, the present application concludes that only the salient pole permanent magnet synchronous motor with direct-axis inductance greater than quadrature-axis inductance can meet the requirements of constant power control, and based on this conclusion, a salient pole permanent magnet synchronous motor decoupling control system with direct-axis inductance greater than quadrature-axis inductance is provided.

[0006] The present application adopts the following technical solutions:

[0007] A salient pole permanent magnet synchronous motor decoupling control system, the direct-axis inductance of the salient pole permanent magnet synchronous motor is greater than the quadrature-axis inductance, and when the salient pole permanent magnet synchronous motor works in a steady state, the phase of the stator current leads the phase of the armature reaction magnetic flux by an angle of α, and the stator current is decomposed into a direct-axis component i d and a quadrature-axis component i q , respectively.

[0008] The direct-axis current i d and the quadrature-axis current i q of the motor satisfy the restriction condition: wherein I ed is the effective value of the stator phase current of the salient pole permanent magnet synchronous motor.

[0009] the direct axis current i d , the quadrature axis current i q and the speed of the motor ω r Also, the following restriction is satisfied: where L md is the direct axis inductance, L mq is the quadrature axis inductance, U ed is the effective value of the stator phase voltage, and ψ0is the flux linkage generated by the permanent magnet rotor in the stator winding;

[0010] The phase of the stator current leads the angle α of the armature reaction magnetic flux by an angle that satisfies: where γ is the internal power factor angle of the motor, R φq is the q-axis magnetic circuit reluctance, and R φd is the d-axis magnetic circuit reluctance.

[0011] Further, the system includes a speed controller, a direct axis current controller, and a quadrature axis current controller. The quadrature axis current command signal and the direct axis current command signal are obtained by the operation of the speed controller, and are subtracted from the quadrature axis current i q and the direct axis current i d respectively to obtain the quadrature axis current and direct axis current deviations. The direct axis voltage signal u d is obtained by the operation of the direct axis current controller, and the quadrature axis voltage signal u q is obtained by the operation of the quadrature axis current controller. After inverse rotation transformation of u d and u q , u α and u β signals are obtained, and after space voltage vector modulation, pulse signals with variable pulse width are formed to control the inverter in the main circuit to drive the motor.

[0012] Further, the decoupling control of the direct axis current and the quadrature axis current is realized by adding the direct axis and quadrature axis armature reaction compensation voltages to the direct axis voltage u d and the quadrature axis voltage u q respectively. The direct axis armature reaction compensation voltage is e sd =-ω r L mq i q , and the quadrature axis armature reaction compensation voltage is e sq =ω r L md i d .

[0013] Further, the system includes a three-phase inverter, a control module, and a speed and position detection device.

[0014] Further, the three-phase inverter is composed of a bridge circuit of power switch MOS tubes, an input end of which is connected with the control chip, and an output end of which is connected with the salient pole permanent magnet synchronous motor; the control module comprises a power supply, the control chip, a control circuit, a power drive circuit, an optical isolation circuit, a current detection circuit and a protection circuit. The current detection circuit is connected with the control chip, and feeds back the detected current information to the control chip. The optical isolation circuit isolates the control signal and the drive signal, and enhances the reliability of the circuit; the speed and position detection device is connected with the motor, and feeds back the collected speed information to the control chip, and six-way PWM signals emitted by the control chip are used to drive the turn-on and turn-off of the power switch MOS tubes, so as to control the operation of the salient pole permanent magnet synchronous motor

[0015] The beneficial effects of the present application are that the salient pole permanent magnet synchronous motor decoupling control system provided by the present application can compensate the coupling terms of the interference in the system in software, can realize high-precision control, and can ensure the stability of the system BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 It is a decoupling control principle diagram of the embodiment of the present application.

[0017] Figure 2 It is a control system structure diagram of the embodiment of the present application.

[0018] Figure 3 It is a decoupling current control system block diagram of the embodiment of the present application.

[0019] Figure 4 It is a stator current vector trajectory diagram of the embodiment of the present application. DETAILED DESCRIPTION

[0020] The present application will be further described in detail in combination with the drawings.

[0021] As shown in the drawings, Figures 1-4 a technical solution is provided by the present application:

[0022] A salient pole permanent magnet synchronous motor decoupling control system, the direct-axis inductance of the salient pole permanent magnet synchronous motor is greater than the quadrature-axis inductance, in the steady-state operation, the phase of the stator current is ahead of the phase of the armature reaction magnetic flux, the lead angle is alpha, the speed proportional integral controller is used to realize the control of the speed omega r of the salient pole permanent magnet synchronous motor with the direct-axis inductance greater than the quadrature-axis inductance, the direct-axis current proportional integral controller is used to realize the control of the direct-axis current i d of the salient pole permanent magnet synchronous motor with the direct-axis inductance greater than the quadrature-axis inductance, and the quadrature-axis current proportional integral controller is used to realize the control of the quadrature-axis current iq Control;

[0023] The direct-axis current i of a salient-pole permanent magnet synchronous motor with a direct-axis inductance greater than its quadrature-axis inductance. d and cross-axis current i q The following constraints must be met: Where I ed This is the effective value of the stator phase current of a salient-pole permanent magnet synchronous motor with a direct-axis inductance greater than its quadrature-axis inductance. (The last part, "I," appears to be a typo and can be left as is.) ed The amplitude is limited, so when i d When increasing in the negative direction, i q The current needs to be reduced accordingly to maintain the stability of the stator phase current amplitude and the direct-axis current i. d and cross-axis current i q in i d -i q On the axis, the center point is (0, 0) and the radius is... The current limiting circle;

[0024] Ignoring the voltage drop across the internal resistance R of the motor stator windings, a salient-pole permanent magnet synchronous motor with a direct-axis inductance greater than its quadrature-axis inductance operates under steady-state conditions. At this time, the direct-axis current i of the motor d Cross-axis current i q And the motor speed ω r It should also meet the following constraints: Where L md It is a direct-axis inductor, L mq It is a quadrature axis inductor, U ed This is the effective value of the stator phase voltage, ψ0 is the magnetic flux linkage generated by the permanent magnet rotor in the stator winding, and the direct-axis current i of the motor at this time. d and cross-axis current i q in i d -i q On the axis, the major axis is located at i. q Coordinate direction, center point is The voltage limit ellipse;

[0025] A decoupling control system for a salient-pole permanent magnet synchronous motor includes a three-phase inverter, a control module, and a speed and position detection device.

[0026] The three-phase inverter is composed of a bridge circuit consisting of power switching MOSFETs. Its input is connected to the control chip, and its output is connected to a salient-pole permanent magnet synchronous motor with a direct-axis inductance greater than the quadrature-axis inductance.

[0027] The control module comprises a power supply, a control chip, a serial communication circuit, a control circuit, a power drive circuit, an optical coupling isolation circuit, a current detection circuit and a protection circuit. The current detection circuit is connected with the control chip, and feeds back the detected current information to the control chip. The optical coupling isolation circuit isolates the control signal and the driving signal, and enhances the reliability of the circuit; the speed and position detection device is connected with the motor, and feeds back the collected speed information to the control chip, and six-way PWM signals are sent out by the control chip to drive the on and off of the power switch MOS tube, so as to control the operation of the salient pole permanent magnet synchronous motor with the direct-axis inductance greater than the quadrature-axis inductance.

[0028] The decoupling of the salient pole permanent magnet synchronous motor comprises the following steps:

[0029] Step one: real-time acquisition of the stator winding current of the salient pole permanent magnet synchronous motor with the direct-axis inductance greater than the quadrature-axis inductance, and transformation to obtain the direct-axis current i d and the quadrature-axis current i q , simultaneously detecting the speed ω r of the motor, and calculating the direct-axis armature reaction voltage e sd and the quadrature-axis armature reaction voltage e sq respectively according to the following formula:

[0030] e sd =-ω r L mq i q

[0031] e sq =ω r L md i d

[0032] Step two: adding the direct-axis armature reaction voltage e sd and the output signal u d1 of the direct-axis current proportional integral controller to obtain the direct-axis control voltage u d , and adding the quadrature-axis armature reaction voltage e sq and the output signal u q1 of the quadrature-axis current proportional integral controller to obtain the quadrature-axis control voltage u q ;

[0033] Step three: rotating transformation of the direct-axis control voltage u d and the quadrature-axis control voltage u q to obtain two orthogonal alternating voltages u α and u β ;

[0034] Step four: adding the two orthogonal alternating voltages u α and uβ The pulse is sent to the pulse width modulation stage to generate SVPWM pulses, which are used to control salient pole permanent magnet synchronous motors with direct-axis inductance greater than quadrature-axis inductance.

[0035] The q-axis magnetic circuit reluctance R of the motor φq The magnetic reluctance R of the magnetic circuit is greater than that of the d-axis φd The phase of its stator current leads the phase angle of the armature reaction flux. in γ is the angle between the excitation voltage and the stator current.

[0036] The stator voltage of phase A of the motor

[0037] Where i A (t) is the A-phase stator current of the salient-pole permanent magnet synchronous motor with a direct-axis inductance greater than its quadrature-axis inductance, R is the internal resistance of the motor, and L is the internal resistance of the motor. σ It's a leakage sensation, e As (t) is the fundamental component of the armature reaction voltage of phase A winding of the motor, and its calculation formula is: e As (t)=-ω r ψ sm sin(ω r t+β), where ψ sm It is the armature reaction flux of the motor, and its calculation formula is: β = 90° + γ + α; e A (t) is the fundamental component of the excitation voltage of phase A winding of the motor, and its calculation formula is: e A (t)=-ω r ψ m sinω r t, where ψ m It is the excitation flux linkage of the motor rotor, and its calculation formula is: e N It is the effective value of the excitation voltage in the stator winding of the motor.

[0038] This invention relates to a decoupling control system and method for a salient-pole permanent magnet synchronous motor with a direct-axis inductance greater than its quadrature-axis inductance. The content includes the direct-axis current i of the salient-pole permanent magnet synchronous motor with a direct-axis inductance greater than its quadrature-axis inductance. d and cross-axis current i q The constraints that must be met for the direct-axis current i d and cross-axis current i q And the motor speed ω r The constraints that must be met, the method for calculating the lead angle α of the armature reaction flux relative to the stator magnetomotive force, and the A-phase stator voltage u A The calculation method of (t) and the coupling term direct-axis armature reaction voltage e sd and cross-axis armature reaction voltage esq The application discloses a decoupling control system of a salient pole permanent magnet synchronous motor with direct-axis inductance greater than quadrature-axis inductance, which is designed by a three-phase inverter, a control module and a speed and position detection device.

[0039] It should be noted that the terms such as "upper", "lower", "left", "right", "front", "back" and the like cited in the application are only for the convenience of clear description, and are not used to limit the scope of the application, and the change or adjustment of the relative relationship is also regarded as the implementation scope of the application without substantial change of the technical content.

[0040] The above is only the preferred embodiment of the application, and the protection scope of the application is not limited to the above-mentioned embodiments, and any technical scheme falling within the idea of the application belongs to the protection scope of the application. It should be pointed out that, for ordinary skilled persons in the art, some improvements and refinements without departing from the principle of the application should be regarded as the protection scope of the application.

Claims

1. A decoupled control system for salient pole permanent magnet synchronous machines, characterized in that, The direct-axis inductance of the salient pole permanent magnet synchronous motor is greater than the quadrature-axis inductance. When the salient pole permanent magnet synchronous motor is in steady operation, the phase of the stator current is ahead of the phase of the armature reaction magnetic flux, the leading angle is α, the stator current is decomposed into direct-axis component i d and quadrature-axis component i q respectively control; the direct-axis current i of the electric machine d and the quadrature-axis current i q satisfying the restriction condition: where I ed is the stator phase current effective value of the salient pole permanent magnet synchronous motor the direct-axis current i d , the quadrature-axis current i q and the rotational speed ω r of the electric machine md also satisfy the limiting condition: where L md is the direct-axis inductance, L mq is the quadrature-axis inductance, U ed is the effective value of the stator phase voltage, and ψ0is the flux linkage generated by the permanent-magnet rotor in the stator winding The phase of the stator current leads the angle a of the armature reaction flux, which satisfies: where γ is the internal power factor angle of the machine, R φq is the q-axis magnetic circuit reluctance, R φd is the d-axis magnetic circuit reluctance.

2. The decoupled control system of a salient pole permanent magnet synchronous motor according to claim 1, characterized in that, The system comprises a speed controller, a direct-axis current controller and a quadrature-axis current controller, the quadrature-axis current instruction signal is obtained through the operation of the speed controller and the direct-axis current instruction signal The quadrature-axis current i q and the direct-axis current i d are subtracted respectively to obtain the quadrature-axis current and direct-axis current deviation, the direct-axis voltage signal u d is obtained through the operation of the direct-axis current controller, the quadrature-axis voltage signal u q is obtained through the operation of the quadrature-axis current controller, the u d and u q are subjected to inverse rotation transformation to obtain u α and u β signals, then the space voltage vector modulation is performed to form a pulse signal with variable pulse width, and the inverter in the main circuit is controlled to drive the motor.

3. The decoupled control system of a salient pole permanent magnet synchronous motor according to claim 1 or claim 2, characterized in that, Decoupled control of direct axis current and quadrature axis current is achieved by adding direct axis and alternating axis armature reaction compensation voltages to the direct axis voltage u d and the quadrature axis voltage u q , respectively, the direct axis armature reaction compensation voltage being e sd = -ω r L mq i q , and the quadrature axis armature reaction compensation voltage being e sq = ω r L md i d .

4. The decoupled control system of a salient pole permanent magnet synchronous motor according to claim 1, wherein, The system comprises a three-phase inverter, a control module and a speed and position detection device.

5. A decoupled control system for a salient pole permanent magnet synchronous machine according to claim 4, characterized in that, The three-phase inverter is composed of a bridge circuit of power switch MOS tubes, the input end of which is connected with a control chip, and the output end of which is connected with a salient pole permanent magnet synchronous motor; the control module comprises a power supply, a control chip, a control circuit, a power drive circuit, an optical isolation circuit, a current detection circuit and a protection circuit; the current detection circuit is connected with the control chip, and feeds back the detected current information to the control chip. The optical isolation circuit isolates the control signal and the drive signal, and enhances the reliability of the circuit; the speed and position detection device is connected with the motor, feeds back the collected speed information to the control chip, and six-way PWM signals emitted by the control chip drive the on and off of the power switch MOS tubes, thereby controlling the operation of the salient pole permanent magnet synchronous motor.

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