High performance position control of permanent magnet synchronous drives

Abstract

In the design and test of electric drive control systems, computer simulations provide a useful way to verify the correctness and efficiency of various schemes and control algorithms before the final system is actually constructed, therefore, reducing development time and associated costs. Nevertheless, the transition from the simulation stage to the actual implementation has to be as straightforward as possible. This paper presents the design and implementation of a position control system for permanent magnet synchronous drives using the dsPIC33FJ32MC204 microcontroller as the target processor to implement the control algorithms. The overall system is simulated and tested in Proteus VSM software which is able to simulate the interaction between the firmware running on the microcontroller and the analogue circuits connected to it. The electric drive model is developed using elements present in the Proteus VSM library. As in any high-performance AC electric drive system, field oriented control is applied. The complete control system is distributed in three control loops, namely torque, speed and position. A standard PID control system, and a hybrid control system based on fuzzy logic, are implemented and tested. The natural variation of motor parameters, such as winding resistance and magnetic flux, are also simulated. Comparisons between the two control schemes are carried out for speed and position control using different error measurements, such as, integral square error, integral absolute error and root mean squared error. Comparison results show a superior performance of the fuzzy-logic-based controller when coping with parameter variations, and by reducing torque ripple, but the results are reversed when periodical torque disturbances are present.