An Identification and I-PD Control of Chopper System with R-L Load using M-Sequence

Abstract

Several methods have been adopted to identify dynamic performance of controlled system and to determine PID parameters in process control system. However, its application to the field of power electronics is seldom seen. In this case, it is desired to reduce the computation time of the microprocessor.
This paper proposes an auto-tuning method of DC current control system which is composed of an identification, a conversion method of transfer function and a determination of control parameters. In the system identification by M-sequence signal, we derive new compensation method for the determination of weighting sequence. In the transfer function conversion and the determination of digital control parameters, the formulas without the term depending on time are derived and have few number of product and division. In order to reduce the computation time, all procedures have been developed in assembler language by using the fixed point number. As a result of comparison of the experimental values and simulation ones, it appeared that the compensation method of the weighting sequence was useful and the auto-tuning was done in short computation time.