Direct instantaneous torque control method of switched reluctance motor based on voltage vector

Abstract

The invention discloses a switched reluctance motor direct instantaneous torque control method based on voltage vectors. The switched reluctance motor direct instantaneous torque control method is characterized in that sectors can be divided according to a torque characteristic curve of a switched reluctance motor, and a size of a hysteresis region can be determined in a self-adapted manner according to a torque pulsation coefficient and an expected torque; by considering a torque output capability of a conducted phase of a commutation region, real-time adjustment of a duty ratio of a voltage of every phase can be carried out according to an operation condition and a conduction rule, and the voltage vectors of the direct instantaneous torque control can be refined. The method provided by the invention is advantageous in that the realization costs are low, the sampling period can be expanded, the current pulsation and the torque pulsation can be reduced, the winding copper loss is low, and the practicability is strong.

Description

technical field [0001] The invention relates to a direct instantaneous torque control method of a switched reluctance motor based on a voltage vector, and belongs to the field of torque control methods of a switched reluctance motor. Background technique [0002] A switched reluctance motor is a motor designed based on the principle of variable reluctance. Switched reluctance motors have many unique advantages over other types of motors. The switched reluctance motor has a double salient pole structure of the stator and rotor, and there are only windings on the stator tooth poles, and there are no windings on the rotor, and there is no permanent magnet. This structure makes the switched reluctance motor suitable for various applications. Harsh environments such as high temperature and strong vibration. Since the switched reluctance motor operates according to the principle of minimum reluctance, the polarity of the winding current will not affect the electromagnetic torque...

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Problems solved by technology

Jin Ye proposed a method to determine the torque distribution of each phase online, but the calculation is tedious and complex, and the sampling frequency of the torque loop is as high as Mhz

[0006] Direct torque control method: select the appropriate voltage vector according to the sector where the current flux linkage is located and the torque error, and keep the size of the flux linkage unchanged. This method can significantly suppress torque ripple, but the selection of the voltage vector does not consider the position information. Negative torque may be generated, reducing motor efficiency

[0007] Direct instantaneous torque control: Robert B Inderka proposed a more concise and effective direct instantaneous torque control method for the nonlinear characteristics of the flux linkage of switched reluctance motors, which does not need to track the flux linkage, through online fitting or offline methods The torque characteristics of the motor are obtained, and the double hysteresis loop control is adopted, which has a fast response and good robustness. However, in each torque loop sampling period, any phase can only be in one of the three states of conduction, freewheeling and off, which can be used The selected voltage vector is limited, and the control effect is greatly affected by the sampling period

In this regard, there is a method to obtain more basic voltage vectors by changing the physical structure of the converter, which improves the problem caused by too few voltage vectors in the traditional direct instantaneous torque control method, but the implementation cost is relatively high

What is more noteworthy is that, unlike the torque distribution method, the traditional direct instantaneous torque control method does not consider the trend of the phase current curve, which may cause the problem that the peak value of the phase current may be too large when the motor is running

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