Motor control system and motor side power factor control method and device

Abstract

The invention discloses a method and device for controlling a motor-side power factor, and a system equipped with the device. The method comprises the following steps: carrying out the control of a motor in a mode: Id'=0, so as to obtain a quadrature axis voltage Uq' and a direct-axis voltage Ud' in a virtual coordinate system in a current control period; calculating a first control value according to the quadrature axis voltage Uq' and the direct-axis voltage Ud'; obtaining a power factor control target value, and calculating a target control value; carrying out the PI control of the difference between a target control value and a first control value so as to obtain coordinate deviation angles, and enabling the coordinate deviation angles to be superposed to a motor angle in a current control period, so as to build a virtual coordinates in a next control period and achieve the control of the motor-side power factor. The method can achieve the accurate control of the motor-side power factor under the condition that there is no need to accurately obtain the operation parameters of the motor, improves the use efficiency and drive efficiency of a frequency converter and the working efficiency of the motor.

Description

technical field [0001] The invention relates to the technical field of motor control, in particular to a method for controlling power factor at the motor side, a device for controlling power factor at the motor side, and a motor control system. Background technique [0002] With the rapid development of frequency conversion control technology and the promotion of the concept of high efficiency and energy saving, the permanent magnet synchronous motor control technology has made great progress, but there are still some deficiencies in the control of the power factor of the permanent magnet synchronous motor: [0003] For example, when the motor is controlled by the control method of Id=0 or MTPA (Maximum Torque Per Ampere, maximum torque current ratio), the power factor is not controlled. If the motor load is large or the field weakening is deep, then Will cause the power factor to become very poor, so that it cannot meet the actual requirements. In addition, when the positi...

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Problems solved by technology

[0003] For example, when the motor is controlled by the control method of Id=0 or MTPA (Maximum Torque Per Ampere, maximum torque current ratio), the power factor is not controlled. If the motor load is large or the field weakening is deep, then Will cause the power factor to become very poor, so that it cannot meet the actual requirements

In addition, when the position sensor is used to estimate the motor angle, since the position estimation is completed based on the relatively accurate operating parameters of the motor, if the operating parameters of the motor are inaccurate, the control of Id=0 will become magnetization or Field weakening control, so that the actual control effect cannot be achieved

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