A sliding mode current control scheme for PWM brushless DC motor drives

Abstract

This paper proposes a sliding mode current control scheme for pulsewidth modulation (PWM) brushless de motor drives. An improved "equivalent control" method is used in this scheme. A simple algorithm is proposed that differs from the original equivalent control method, which requires extensive calculation to estimate the load parameters. This algorithm can be implemented using logic circuits. Moreover, using autotuning, the proposed algorithm can be applied without load information. An operating principle for the power stage switching devices called single-side firing is also proposed. Single-side firing solves the dead-time problem, allowing the PWM frequency to be increased and the sampling rate to be raised. This paper explains the current control algorithm, single-side firing principle, and implementation of the proposed scheme in detail. Simulations and experimental results are given to show the validity of this scheme.