Simplified Fuzzy Logic Speed Controller for Vector Controlled Permanent Magnet Synchronous Motor Drives

Abstract

This paper presents simplified fuzzy logic speed control (FLSC) for vector controlled permanent magnet synchronous motor (PMSM) drives. The fuzzy logic controller is a multi-parameter controller where the performance depends upon the chosen shape of membership function (MF), rule base and scaling factor. In this paper, rule base is viewed as a control strategy to design the simplified FLSC. The FLSC simplification is designed by rule base simplification through two diferrent approaches. The first approach implements the rule simplification by reducing the number of MF used and adjusting the arrangement of chosen MFs for each fuzzy variable. The second approach obtains the rule simplification by eliminating the rules that are infrequently fired by the PMSM drives while maintaining the dominant rules. In doing so, the standard 49 rules is simplified become 9 rules by first approach while the other approach produces 7 rules. The efficacies of the FLSC simplifications are investigated based on comparative studies of speed performances with the standard FLSC which consisting of 49 rules. The standard FLSC is designed based on common criteria from numerous literatures. The mathematical model of the PMSM drive system is simulated in MATLAB environment with Simulink and Fuzzy Logic Toolbox. The simulation results are validated with the experimental results for various operating conditions, load disturbances and inertia variations. The simulation and experimental results showed that the simplified FLSCs obtain nearly equivalent performance with the standard FLSC, thus indicating the effectiveness of the rule simplification