Weak magnetic speed regulating method for induction motor

Abstract

The invention provides a weak magnetic speed regulating method for an induction motor, and belongs to the technical field of alternating current motors and control thereof. The method comprises the following steps of: determining actual given values of exciting current and torque current by using a current control algorithm based on current optimal working trajectory; acquiring space vector pulse width modulation (SVPWM) through a current loop, and obtaining calculation action time of two adjacent non-zero voltage vectors; determining actual action time of the two non-zero voltage vectors through a modulation algorithm so as to acquire a running voltage of the motor; and at the same time, determining a field current calculation given value of the next time through the calculation action time of the two adjacent non-zero voltage vectors. By the method, an operating range of speed constant power of the induction motor is enlarged, a utilization ratio of the voltage and the current of an inverter is increased, and the maximum output torque of the induction motor is improved.

Description

A method for speed regulation of induction motor with field weakening technical field The invention belongs to the technical field of AC motors and their control, and in particular relates to a field-weakening speed regulation method for induction motors. Background technique AC motor speed regulation methods include variable slip speed regulation, pole variable speed regulation and frequency conversion speed regulation. Variable slip speed regulation is divided into energy consumption type and feedback type variable slip speed regulation. The former consumes a lot of energy during speed regulation, the operating efficiency is low, and the scope of use is also limited; Energy feedback power supply, high operating efficiency, such as series pole speed control and double-fed speed control system, but this method is only suitable for asynchronous motors with winding leads on the rotor, not for induction motors. Pole-changing speed regulation cannot be continuously adjusted, ...

AI Technical Summary

Problems solved by technology

Within the operable range of the current, determining the appropriate time to enter the constant voltage area can improve the operating efficiency of the motor in the constant voltage area, but there is no scheme that mentions the judging conditions for entering the constant voltage area

However, the existing space voltage vector overmodulation algorithm is relatively complicated, and it is necessary to calculate the holding angle and the modulation coefficient in the current loop.

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