IPMSM field weakening control method with DC bus voltage sag being considered

Abstract

The invention discloses an IPMSM field weakening control method with DC bus voltage sag being considered. The method comprises the following steps: to begin with, obtaining motor parameters through off-line identification; then, calculating a direct axis current through MTPA control method formulas; judging whether entering a field weakening region and calculating a compensated direct axis current; adding the direct axis current obtained under the MTPA control method and the compensated direct axis current to obtain a given direct axis current; and finally, calculating a given quadrature axiscurrent by using a current limit circle equation of an IPMSM. The method eliminates the influence of out of control of the motor caused under a general control method due to change of base speed of the motor likely to be caused by change of DC bus voltage through a field weakening control method compensated by negative direct axis current, and can still maintain constant-speed operation of the motor under the condition of sharp drop of the bus voltage.

Description

technical field [0001] The invention relates to motor technology, in particular to an IPMSM magnetic field weakening control method considering the DC bus voltage drop. Background technique [0002] The built-in permanent magnet synchronous motor (IPMSM) is playing an increasingly important role in the field of AC servo due to its advantages of high efficiency, simple structure and small size. In order to broaden the motor speed range of the permanent magnet synchronous motor, various methods have been proposed. Due to the existence of permanent magnets in IPMSM, the counter electromotive force will exceed the loading voltage at high speed, and a weak magnetic current must be applied to maintain the stability of the motor at high speed. [0003] The traditional IPMSM field weakening control method is based on the fact that the DC bus voltage is a constant value, mainly including: formula calculation method, table look-up method, gradient descent method and other algorithms....

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Problems solved by technology

Among them, the formula method completely depends on the parameters of the motor. Since the inductance and flux parameters of the motor are changed by the change of the current during operation, it is no longer suitable for direct formula calculation. This method has only theoretical significance and is rarely used in practice. The look-up table method requires a large amount of experimental data to build tables. Although the dependence of the formula method on the motor parameters is solved, it is not universal and difficult to implement. The gradient descent method is based on the voltage decrease of the voltage limit ellipse of the motor. The angle between the direction and the constant torque operation curve is used to determine the field weakening area where the motor operates. This method avoids the inconvenience of using a large amount of experimental data, but the implementation procedure is complicated

[0004] In 2011, Jae Hyuk Lee proposed a method based on the speed, rotation The method of establishing a 3-dimensional instruction table based on torque and bus voltage solves the problem of speed imbalance caused by the saturation of the current regulator, and also enhances the dynamic performance, but it is difficult to create the table; in 2012, Huang Surong, Wang Weichen and others, in In the article "Control Strategy of Electric Vehicle Permanent Magnet Synchronous Motor Based on Dynamic Change of Bus Voltage" (Motor and Control Application, 2012, 39(10): 24-29), it is proposed to convert the actual bus voltage to the rated bus voltage equivalently, The method of adjusting the electrical angular velocity command value as the basis of the look-up table has broadened the scope of the motor work area, but still needs to create a table; in 2013, Chen Ning, Zhang Yue and others, in "Buried Permanent Magnet Synchronous Motor Drive System In the article "(Control Theory and Application, 2013, 30(06):717-723), it is proposed that when the bus voltage drops, the closed-loop control of the effective voltage vector is introduced, which can correct the direct axis current in real time and avoid The shortcoming of current regulator saturation is eliminated, but due to the introduction of many PI regulators, it is difficult to adjust

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