Rotor Thyristor Speed Control System For Wound-Rotor Induction Motor

With the fast development of power electronic technology,varieties of speed setting controllers have been created.Because of the advantages of cheap price、reliable operation、 easy maintenance,the asynchronous motor is used widely, especially in the industry field. There are lots of ways to control the speed of asynchronous motor,the best one is frequency control.But with the high costing of system,it is limited used.In general speed control system, we usually use cascade speed regulation and the stator voltage speed regulation.Controller introduced in this paper is developed with cooperation of company in Dalian.After considering the costing and requirements,the system combines cascade speed regulation and rotor thyristor speed regulation to realize stepless speed regulation at a certain speed range.In order to solve the difficulties in controlling motor, Texas Instrument designed a series of chips for motor controllers, especially the performance of TMS320F28335is excellent. Compared with the digital signal processor of last generation,the floating point arithmetic ability of TMS320LF28335has been improved.As a result,a moter controlling scheme can be rapidly and easily developed by using the TMS320LF28335chip.This project use the TMS320LF28335chip as the core of digital controlling, cooperate with kinds of hardware circuits to fulfill the requirements.In this paper the thoery and realization method of rotor thyristor speed regulation system have been introduced,also there are details of software and hardware.The software part includes digital filter,the signal processing,communications with panel and kinds of realization of control logics,etc.The hardware part includes the rotor voltage zero crossing detection circuit,voltage and current detection circuit,trigger circuit of thyristor and filter circuit,etc.After the modulation of the device,the whole system has a stable operation and can accomplish the goal of speed regulation.