CN100440720C - Hybrid speed regulation method for permanent magnet synchronous motor - Google Patents

Abstract

The hybrid speed regulation method of the permanent magnet synchronous motor disclosed in the present invention is based on the torque characteristics of the salient pole permanent magnet synchronous motor, that is, it has the ability to adjust the power angle to the load disturbance, and the other control speed regulation method is applied to the permanent magnet synchronous motor In the speed regulation, when the permanent magnet synchronous motor is started, the self-control vector control speed regulation is adopted. When the motor enters a steady state, when the feedback speed reaches the given speed value, the self-control speed regulation switches to other control speed regulation. When other control speed regulation is used, the voltage vector of the corresponding frequency is directly output according to the given speed, which is equivalent to the speed open-loop control. Compared with the automatic control speed regulation, the links such as speed measurement, speed regulator and current regulator are eliminated, and the errors in the above links are eliminated. . When the speed is controlled by other control, the power angle is automatically adjusted according to the load disturbance to realize the speed regulation, and the speed accuracy is high. This speed regulation method is especially suitable for servo occasions where the load changes little when the motor is running in a steady state and high speed accuracy is required.

Description

Hybrid speed regulation method for permanent magnet synchronous motor

technical field

The invention relates to a speed regulation method of a permanent magnet synchronous motor, in particular to a speed regulation method of a salient pole type permanent magnet synchronous motor which requires high speed precision in a steady state.

Background technique

At present, self-controlled vector control is a main speed regulation method of permanent magnet synchronous motor. The speed regulation system of this method is double-loop regulation of speed loop and current loop. Among them, the current loop has two regulators of quadrature axis current and direct axis current. (As shown in Figure 1). The adjustment steps are: the speed given _nr and _the speed feedback n take the error to do the speed PI (proportional integral) operation, and the given value i _qr of the quadrature axis current component of the stator is obtained. Quadrature axis current PI calculation, get the stator quadrature axis voltage component u _q ; usually the stator direct axis current component i _dr is given as zero, and the error between this value and the feedback direct axis current component i _d is used for the direct axis current PI calculation to get The stator direct-axis voltage component u _d ; the stator AC and direct-axis voltage components are synthesized into a voltage vector, which is inversely transformed by Park, and the voltage is applied to the motor (PMSM) through a space vector pulse width modulation (SVPWM) inverter. Among them, the rotor position is detected by the position sensor, the feedback speed n is calculated by the rotor position θ, and the feedback alternating and direct axis currents i _q and i _d are obtained by transforming the actual stator three-phase current through dq0.

The disadvantages of this speed regulation method are: there are position detection errors, and then there are speed measurement errors; there are current detection errors, and then there are errors in the AC and D axis currents fed back; the performance of the regulator is related to the proportional and integral parameters, and a set of PI parameters Can not take into account the dynamic and steady-state performance of the motor.

The existence of position, speed measurement, and current feedback errors and the characteristics of the regulator to adjust according to the error make the motor speed fluctuate around the given value, or even deviate from the given value, and the accuracy of the motor speed is difficult to guarantee.

Contents of the invention

The purpose of the present invention is to provide a hybrid speed regulation method for a permanent magnet synchronous motor, so as to eliminate the motor speed error caused by the position detection error, speed measurement error, current detection error and the regulator's own characteristics when the motor is running in a steady state. Improve the adjustment accuracy of the speed.

In order to achieve the above-mentioned purpose, the present invention is based on the salient polarity of the permanent magnet synchronous motor, that is, the torque angle (the angle between the current vector and the direct axis) corresponding to the maximum electromagnetic torque point is in the [90 °, 135 °] interval, The power angle corresponding to the maximum torque point (the angle between the voltage vector and the quadrature axis) is also within a range, and the torque can be adjusted by using other control speed regulation to widen the power angle range, and the combination of self-control speed regulation and other control speed regulation speed regulation method.

The hybrid speed regulation method of the permanent magnet synchronous motor of the present invention is characterized in that when the permanent magnet synchronous motor is started, the self-controlled vector control speed regulation is adopted, and when the motor enters a steady state, when the feedback speed reaches a given speed value, it locks The quadrature-axis component u _q , the direct-axis component u _d and the rotor position angle θ ₀ of the output voltage vector are switched from self-control speed regulation to other control speed regulation, with the rotor position angle θ ₀ at the moment of cut-in as the initial value, at a given speed n _r calculates from the given rotor position angle θ′, after the quadrature-axis voltage component u _q and the direct-axis voltage component u _d are inversely transformed by Park, the voltage is applied to the motor through the space vector pulse width modulation inverter. Before voltage, detect the actual rotor position angle θ, add the angle difference Δθ between θ′ and θ to the initial value δ ₀ of the power angle to obtain the actual power angle value δ, and judge the range of δ, if δ is in the set other control speed regulation interval [δ ^- , δ ⁺ ], then continue to use other control speed regulation, if it exceeds the other control speed regulation range, then switch to self-control speed regulation, when the motor enters the steady state again, when the feedback speed reaches the given speed value, start again Cut into other control speed regulation, repeat the above process; the above δ ₀ , u _q and u _d are the initial value of the power angle, the quadrature axis component u _q and the direct axis component u of the voltage vector at the moment when the automatic control speed regulation cuts into the other control speed regulation _d , δ ^- , δ ⁺ are the lower limit and upper limit of the set power angle respectively.

In the above-mentioned separate control speed regulation interval [δ ^- , δ ⁺ ], the torque angle β corresponding to δ ⁺ is in the range of 90° to β _max , and β _max is calculated according to the following formula

T _emax ＝1.5P[ψ _f i _q +0.5(L _d -L _q )i _s ² sin2β _max ]

In the formula, T _emax is the maximum electromagnetic torque value, P is the number of pole pairs of the motor, ψ _f is the amplitude of permanent magnet flux linkage, i _q is the quadrature axis current value, L _d , L _q are the stator direct axis and quadrature axis respectively Inductance value, i _s is the current vector magnitude.

The torque angle β corresponding ^to δ is in the range of 0° to 90°. In order to reduce the current loss, the torque angle ^β corresponding to δ should be close to 90°.

The beneficial effects of the present invention are:

The present invention adopts a speed regulation method combining self-control speed regulation and other control speed regulation. When the permanent magnet synchronous motor is started, self-control speed regulation is adopted. When the motor enters a steady state, other control speed regulation is adopted to directly output corresponding The voltage vector of the frequency is equivalent to the speed open-loop control. Compared with the self-controlled speed regulation, the speed measurement, speed regulator and current regulator are eliminated, and the errors in the above links are eliminated. When the speed is controlled by other control, the power angle is automatically adjusted according to the load disturbance to realize the speed regulation, and the speed accuracy is high. This speed regulation method is especially suitable for servo occasions where the load changes little when the motor is running in a steady state and high speed accuracy is required.

Description of drawings

Figure 1 is a block diagram of the self-controlled vector control system;

Figure 2 is the vector diagram of the self-control vector control system. In the figure, a is the axis of stator A-phase winding, V _s is the voltage vector, i _s is the current vector, θ is the rotor position angle, d is the rotor direct axis, and q is the rotor alternating current. axis;

Figure 3 is the electromagnetic torque-torque angle relationship curve of the salient pole permanent magnet synchronous motor. In the figure, curve 1 is the permanent magnet torque, curve 2 is the reluctance torque, and curve 3 is the synthetic electromagnetic torque, and the intersection point A is the torque Torque value when angle β=90°;

Figure 4 is the electromagnetic torque-power angle relationship curve of the salient pole permanent magnet synchronous motor. In the figure, the dotted line corresponds to the power angle value δ ₀ and the torque value at point A when the torque angle β=90°, and the left solid line corresponds to other points The lower limit power angle value δ ^- and torque value of control operation are point B, and the right solid line corresponds to the upper limit power angle value δ ⁺ and torque value of other control operation point C;

Fig. 5 is the block diagram of other control vector control system. In the figure, u _d and u _q are the direct and quadrature axis components of the locked voltage vector when the self-control speed regulation cuts into the other control speed regulation, and θ′ and θ are respectively the other control regulation The given rotor position angle and the actual rotor position angle at high speed;

Figure 6 is the vector diagram of the vector control system of the other control type. In the figure, a is the axis of the A-phase winding of the stator, d' is the virtual d-axis generated by the speed regulation of the other control from the given rotor position angle, V _s ' is the time of the speed regulation of the other control V ^s is the voltage vector when the automatic control cuts into other control, Δδ is the power angle change value, q is the quadrature axis of the rotor, θ′ and θ are the self-given rotor position angle and the actual rotor position angle when the other control speed is adjusted respectively position angle.

Detailed ways

Further illustrate the present invention below in conjunction with accompanying drawing.

The hybrid speed regulation method of the permanent magnet synchronous motor of the present invention: when the permanent magnet synchronous motor starts, adopt the traditional self-control = formula vector control method (as shown in Figure 1), and the system is realized by a speed outer loop and two current inner loops Speed regulation is the _id 0 rotor field orientation scheme, the vector diagram is shown in Figure 2.

When the motor enters a steady state, when the feedback speed reaches a given speed value, the quadrature axis component u _q , the direct axis component u _d and the rotor position angle θ ₀ of the output voltage vector are locked, and the automatic control speed regulation is switched to other control speed regulation (see Fig. 5, Fig. 6), take the rotor position angle θ ₀ at the time of cut-in as the initial value, calculate the self-given rotor position angle θ′ according to the given speed n _r , in each speed regulation cycle, θ′ is as follows calculate

θ _k '=θ _k-1 '+Δθ'

In the formula, θ _k-1 ′ and θ _k ′ are the self-set rotor position angles of the previous cycle and this cycle respectively, and Δθ′ is the angle increment calculated according to the given speed, which is calculated according to the following formula

Δθ'＝k·n _r ·θ _min

In the formula, n _r is the given speed, θ _min is the minimum angle increment, and k is the coefficient.

According to the self-given rotor position angle θ′, the quadrature-axis voltage component u _q and the direct-axis voltage component u _d (synthetic voltage vector V _s ′) are inversely transformed by Park, and then applied by a space vector pulse width modulation (SVPWM) inverter Voltage to the motor (PMSM).

In each speed regulation cycle, the power angle δ _k is calculated by the following formula

δ _k ＝δ ₀ +θ _k ′-θ _k

In the formula, δ ₀ is the power angle value at the time of cut-in, and θ _k is the actual rotor position angle in this cycle.

Judging the range of δ _k , if δ _k is in the set external control speed regulation range [δ ^- , δ ⁺ ], continue to use the external control speed regulation, if it exceeds the external control speed regulation range, switch to the automatic control speed regulation to avoid loss Step, when the motor enters the steady state again, when the feedback speed reaches the given speed value, it will switch to other control speed regulation again, and repeat the above process.

In the above-mentioned separate control speed regulation interval [δ ^- , δ ⁺ ], the torque angle β corresponding to δ ⁺ is in the range of 90°～β _max , and β _max is calculated by the following formula

T _emax ＝1.5P[ψ _f i _q +0.5(L _d -L _q )i _s ² sin 2β _max ]

In the formula, T _emax is the maximum electromagnetic torque value, P is the number of pole pairs of the motor, ψ _f is the amplitude of permanent magnet flux linkage, i _q is the quadrature axis current value, L _d , L _q are the stator direct axis and quadrature axis respectively Inductance value, i _s is the current vector magnitude.

The torque angle β corresponding ^to δ is in the range of 0° to 90°. In order to reduce the current loss, the torque angle ^β corresponding to δ should be close to 90°.

Claims (3)

1. the mixed speed regulating method of permanent magnet synchronous motor, it is characterized in that when permanent magnet synchronous motor starts, adopt the speed governing of autocontrol vector control, when described motor enters stable state, in feedback rotating speed onspeed value constantly, the quadrature axis component u of locking output voltage vector _q, direct axis component u _dWith rotor position angle θ ₀, cut him by the speed governing of autocontrol vector control and control speed governing, with incision rotor position angle θ constantly ₀Be initial value, press given speed n _rCalculate from given rotor position angle θ ', with the quadrature axis component u of voltage vector _qWith direct axis component u _dAfter the Park inverse transformation, apply voltage to described motor by the space vector pulse width modulation inverter, apply before the voltage at every turn, detect the actual rotor angular position theta, with angular difference Δ θ and the merit angle initial value δ of θ ' with θ ₀Addition obtains actual work angle value δ, judges the δ scope, and he controls speed regulating section [δ if δ is setting ^-, δ ⁺], then continue to adopt him to control speed governing, if having exceeded him controls speed regulating section, then switch to the speed governing of autocontrol vector control, when described motor enters stable state once more, in feedback rotating speed onspeed value constantly, cut him once more and control speed governing, repeat said process; Above-mentioned δ ₀Cut him for the speed governing of autocontrol vector control and control speed governing merit angle initial value constantly, δ ^-, δ ⁺Be respectively the merit angle lower limit and the higher limit of setting.

2. the mixed speed regulating method of permanent magnet synchronous motor according to claim 1 is characterized in that δ ⁺Corresponding angle of torsion β is at 90 °～β _MaxIn the scope, β _MaxBe calculated as follows

T _emax＝1.5P[ψ _fi _q+0.5(L _d-L _q)i _s ²sin2β _max]

In the formula, T _EmaxBe maximum electromagnetic torque value, P is the motor number of pole-pairs, ψ _fBe permanent magnetism magnetic linkage amplitude, i _qBe to hand over shaft current value, L _d, L _qBe respectively a stator d-axis and a friendship axle inductance value, i _sIt is the current phasor amplitude; δ ^-Corresponding angle of torsion β is in 0 °～90 ° scopes.

3. the mixed speed regulating method of permanent magnet synchronous motor according to claim 2 is characterized in that δ ^-Corresponding angle of torsion β is near 90 °.

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