Research on system of self-controlled soft start with variable frequency for synchronous motor

High-power synchronous motor is difficult to start and unable to start and stop freely, so it must be long-running. This will cause a lot of energy waste. In order to solve the problem, devices of self-controlled soft start with variable frequency for high-power synchronous motor are researched and developed. The TMS320F2812 DSP is used as main control chip to do all the control strategies in this soft-start platform. This paper also gives a detailed method to do with the error signal of misleading zero-crossing points of back-EMF caused by inverter commutation, and describes the problem at the switch point from self impulse to back-EMF zero-crossing detection. It can get the rotor position without position sensor by accurate detection of motor back-EMF zero-crossing at medium and high speed. In the prototype platform, the motor can be soft started from standstill to rated speed stably and reliably.