CN201435710Y - Direct torque control device of permanent magnet synchronous motor - Google Patents

Abstract

The utility model relates to a direct torque control device of a permanent magnet synchronous motor, which belongs to the technical field of AC (alternating-current) motor transmission. The device comprises a permanent magnet synchronous motor, a signal detecting circuit, a processer and an inverter. A current signal of the permanent magnet synchronous motor and a voltage signal of a DC (direct-current) bus are transmitted to the signal detecting circuit respectively; and the signals are sent to the processor by the signal detecting circuit to be processed, and then switching signals are obtained and transmitted to the inverter, so as to control the motor. By adopting the torque control device, reference voltage vectors are estimated in a stator revolution coordinate according to stator flux amplitude errors and electromagnetic torque errors respectively, and then are transformed to a stator two-phase static coordinate, and finally the switching signal of the inverter is produced in aspace vector modulation manner to control the permanent magnet synchronous motor. The utility model adopts a space vector modulation method and replaces the traditional hysteretic comparator with a proportional controller, thereby effectively reducing the flux linkage pulsation and the torque pulsation; and the adopted voltage vector estimation method is simple, so that the control system structure is simplified.

Description

A kind of direct torque control device of permagnetic synchronous motor

Technical field

The utility model belongs to alternating current machine drive technology field, especially a kind of direct torque control device of permagnetic synchronous motor.

Background technology

Direct torque control is a kind of high performance AC speed regulating control strategy, is at first used at asynchronous machine and proposition respectively by the depenbrock of Germany and the takahashi of Japan, and corresponding product has been released by ABB AB in the back in the nineties in 20th century.Professor Rahman of University of New South Wales in 1997 is incorporated into the direct torque control method in the permagnetic synchronous motor (PMSM).

The conventional direct torque control method of permagnetic synchronous motor adopts torque hysteresis loop comparator and magnetic linkage hysteresis loop comparator, according to the position of stator magnetic linkage, chooses suitable voltage vector in the switch list magnetic linkage and torque are controlled.Because alternative voltage vector has only 8, the voltage vector of selection can't satisfy the double requirements of system to magnetic linkage and rotating speed simultaneously, can cause electric system bigger torque and magnetic linkage fluctuation to occur; In addition, it is non-constant that hysteresis loop comparator can cause the switching frequency of system.In recent years, space vector modulation (SVM) method is introduced in direct torque control, and as patent ZL 200710019081, but the voltage estimate method that is adopted is comparatively complicated.

The utility model content

The purpose of this utility model has been to overcome the above-mentioned defective of existing direct torque control method, and a kind of novel direct torque control method of permagnetic synchronous motor is provided.This method utilizes space vector modulation technique to obtain more, continually varying space voltage vector, and substitute hysteresis loop comparator with the voltage estimating algorithm, control method is simple and realized accurate control to stator magnetic linkage and motor electromagnetic torque, has improved the performance of Direct Torque system.

To achieve these goals, the utility model has been taked following technical scheme.The utility model comprises permagnetic synchronous motor, signal deteching circuit, processor and inverter.Wherein:

Permagnetic synchronous motor is connected with signal deteching circuit, and the current signal of permagnetic synchronous motor is exported to signal deteching circuit;

Signal deteching circuit is connected with inverter, and the DC bus-bar voltage signal of inverter output permagnetic synchronous motor is given signal deteching circuit;

Signal deteching circuit is connected with processor, and output voltage, the current signal of signal deteching circuit are delivered to processor;

Processor is connected with inverter, and the switching signal of processor output is given inverter;

Inverter is connected with permagnetic synchronous motor, and inverter output three-phase alternating current is given permagnetic synchronous motor.

Control method of the present utility model: be to estimate reference voltage vector under the stator rotating coordinate system respectively according to stator magnetic linkage amplitude error and electromagnetic torque error, again reference voltage vector is transformed under the stator two-phase rest frame, produce the switching signal of inverter with the control permagnetic synchronous motor in the space vector modulation mode at last.

The processor of realizing this control method comprises 3/2 conversion module, magnetic linkage and torque estimating module, magnetic linkage voltage transformation module, torque voltage transformation module, coordinate transformation module and SVM module, all realizes that with software following steps are arranged successively in processor:

1) estimates current stator magnetic linkage and electromagnetic torque according to the voltage, the current signal that are input to processor through 3/2 conversion module, magnetic linkage and torque estimating module, wherein, 3/2 conversion module is finished the coordinate transform function, and magnetic linkage and torque estimating module realize magnetic linkage and torque estimating;

2) magnetic linkage and torque estimating module output magnetic linkage amplitude | ψ _s| with given magnetic linkage amplitude | ψ _s ^*| error obtain reference voltage vector component u ' through the magnetic linkage voltage transformation module _xThe torque T and the given torque T of magnetic linkage and the output of torque estimating module ^*Error obtain reference voltage vector component u ' through the over torque voltage transformation module _yThe xy coordinate is the stator rotating coordinate system, and wherein, the x axle is located along the instantaneous pointing direction of stator magnetic linkage, and the y axle is positioned the direction that the x axle is rotated counterclockwise 90 degree;

3) to reference voltage u ' _x, u ' _yCarry out amplitude limit, obtain u _x ^*, u _y ^*Respectively as the output of magnetic linkage voltage transformation module 7 and torque voltage transformation module;

4) coordinate transformation module is realized the coordinate system transformation function, with the u of input _x ^*, u _y ^*Transform to the static α β of stator coordinate system, obtain component of voltage u _α ^*And u _β ^*

5) SVM module implementation space Vector Modulation function is delivered to the u of SVM module _α ^*, u _β ^*Produce the switching signal S of inverter by space vector modulation algorithm _a, S _b, S _cControl inverter.

The utlity model has following advantage:

1) adopts space vector modulating method and substitute traditional hysteresis loop comparator, can effectively reduce the pulsation of magnetic linkage and torque with proportional controller;

2) the voltage vector evaluation method of Cai Yonging is simple, but the simplified control system structure makes it to be easy to realize;

3) guaranteed that inverter switching frequency is constant, can reduce switching loss and make full use of power device.

Description of drawings

Fig. 1 is a system architecture diagram

Fig. 2 is the coordinate system schematic diagram

Among the figure: 1, permagnetic synchronous motor, 2, signal deteching circuit, 3, processor, 4, inverter, 5,3/2 conversion module, 6, magnetic linkage and torque estimating module, 7, the magnetic linkage voltage transformation module, 8, torque voltage transformation module, 9, coordinate transformation module, 10, the SVM module.

Embodiment

The utility model is described in further detail below in conjunction with Fig. 1, Fig. 2:

As shown in Figure 1, present embodiment includes permagnetic synchronous motor 1, signal deteching circuit 2, processor 3 and inverter 4.Wherein, module 5 is a control algolithm to module 10, all realizes by software in processor 3.Concrete implementation step is as follows:

1) the DC bus-bar voltage u of the permagnetic synchronous motor 1 that detects by signal deteching circuit 2 _Dc, stator winding line current signal i _a, i _bBe input to processor 3, also promptly this signal enters 3/2 conversion module 5, carries out coordinate transform through 3/2 conversion module 5 and obtains current component i under the α β coordinate system _α, i _βWith component of voltage u _α, u _β, and above-mentioned signal delivered to magnetic linkage and torque estimating module 6, then specific algorithm is as follows:

$\left[\begin{array}{c}{i}_{\mathrm{\α}}\\ i_{\mathrm{\β}}\end{array}\right]=\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \frac{\sqrt{3}}{2}& -\frac{\sqrt{3}}{2}\end{array}\right]\left[\begin{array}{c}{i}_a\\ i_b\\ -i_a-i_b\end{array}\right]$

$\left[\begin{array}{c}{u}_{\mathrm{\α}}\\ u_{\mathrm{\β}}\end{array}\right]=u_{\mathrm{dc}}\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \frac{\sqrt{3}}{2}& -\frac{\sqrt{3}}{2}\end{array}\right]\left[\begin{array}{c}{S}_a\\ S_b\\ S_c\end{array}\right]$

S in the formula _a, S _b, S _cSwitching signal for current time inverter 4.

2) estimate stator magnetic linkage component ψ under the α β coordinate system by magnetic linkage and torque estimating module 6 _{S α}With ψ _{S β}, current magnetic linkage amplitude | ψ _s| and torque estimated value T, algorithm is as follows:

ψ _sα＝∫(u _α-R _si _α)dt

ψ _sβ＝∫(u _β-R _si _β)dt

$\left|{\mathrm{\ψ}}_s\right|=\sqrt{{{\mathrm{\ψ}}_{\mathrm{s\α}}}^2+{{\mathrm{\ψ}}_{\mathrm{s\β}}}^2}$

$T=\frac{3}{2}{N}_p({\mathrm{\ψ}}_{\mathrm{s\α}}{i}_{\mathrm{\β}}-{\mathrm{\ψ}}_{\mathrm{s\β}}{i}_{\mathrm{\α}})$

R in the formula _sBe the stator resistance of permagnetic synchronous motor, N _pNumber of pole-pairs for permagnetic synchronous motor.

3) magnetic linkage and torque estimating module 6 output magnetic linkage amplitudes | ψ _s| with given magnetic linkage amplitude | ψ _s ^*| error obtain reference voltage vector component u ' through magnetic linkage voltage transformation module 7 _x, algorithm is as follows:

$u_x^{\′}=k_2\×\left(\right|{\mathrm{\ψ}}_s^{*}|-|{\mathrm{\ψ}}_s\left|\right)$

K in the formula ₂＞0.

4) the torque T and the given torque T of magnetic linkage and 6 outputs of torque estimating module ^*Error obtain reference voltage vector component u ' through over torque voltage transformation module 8 _y, algorithm is as follows:

$u_y^{\′}=k_1\×(T^{*}-T)$

K in the formula ₁＞0.

5) to reference voltage u ' _x, u ' _yCarry out amplitude limit, obtain u _x ^*Output, u as magnetic linkage voltage transformation module 7 _y ^*As the output of torque voltage transformation module 8, specific algorithm is as follows:

If $\sqrt{{u_x^{\′}}^2+{u_y^{\′}}^2}>\frac{u_{\mathrm{dc}}}{\sqrt{3}}$

Then $u_x^{*}=\frac{u_{\mathrm{dc}}}{\sqrt{3}\sqrt{{u_x^{\′}}^2+{u_y^{\′}}^2}}{u}_x^{\′}$

$u_y^{*}=\frac{u_{\mathrm{dc}}}{\sqrt{3}\sqrt{{u_x^{\′}}^2+{u_y^{\′}}^2}}{u}_y^{\′}$

Otherwise $u_x^{*}=u_x^{\′}$

$u_y^{*}=u_y^{\′}$

6) coordinate transformation module 9 is according to the u of magnetic linkage position θ with input _x ^*, u _y ^*Be transformed into the component of voltage u under the α β coordinate system _α ^*And u _β ^*, algorithm is as follows:

$\cos \mathrm{\θ}=\frac{{\mathrm{\ψ}}_{\mathrm{s\α}}}{\left|{\mathrm{\ψ}}_s\right|}$

$\sin \mathrm{\θ}=\frac{{\mathrm{\ψ}}_{\mathrm{s\β}}}{\left|{\mathrm{\ψ}}_s\right|}$

$\left[\begin{array}{c}{u}_{\mathrm{\α}}^{*}\\ u_{\mathrm{\β}}^{*}\end{array}\right]=\left[\begin{array}{cc}\cos \mathrm{\θ}& -\sin \mathrm{\θ}\\ \sin \mathrm{\θ}& \cos \mathrm{\θ}\end{array}\right]\left[\begin{array}{c}{u}_x^{*}\\ u_y^{*}\end{array}\right]$

7) deliver to the u of SVM module 10 _α ^*, u _β ^*Produce switching signal S by space vector modulation algorithm _a, S _b, S _cControl inverter 4, and then drive motors.

Fig. 2 is the coordinate system schematic diagram, comprises xy coordinate system and α β coordinate system.The xy coordinate is the stator rotating coordinate system, and wherein, the x axle is located along the instantaneous pointing direction of stator magnetic linkage, and the y axle is positioned the direction that the x axle is rotated counterclockwise 90 degree; α β coordinate is the stator rest frame, and wherein, the α axle is positioned at stator A phase winding axis direction, and the β axle is positioned the direction that the α axle is rotated counterclockwise 90 degree; Angle between x axle and the α axle is θ.

Claims (1)

1, a kind of direct torque control device of permagnetic synchronous motor is characterized in that: comprise permagnetic synchronous motor (1), signal deteching circuit (2), processor (3) and inverter (4); Wherein:

Permagnetic synchronous motor (1) is connected with signal deteching circuit (2), and the current signal of permagnetic synchronous motor (1) is exported to signal deteching circuit (2);

Signal deteching circuit (2) is connected with inverter (4), and the DC bus-bar voltage signal of inverter (4) output permagnetic synchronous motor (1) is given signal deteching circuit (2);

Signal deteching circuit (2) is connected with processor (3), and voltage, the current signal of permagnetic synchronous motor (1) are delivered to processor (3), and processor (3) is given inverter (4) through calculating switching signal;

Inverter (4) is connected with permagnetic synchronous motor (1), and inverter (4) output three-phase alternating current is given permagnetic synchronous motor (1).

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