An improved constant-frequency digital hysteresis current control strategy

An improved constant-frequency digital hysteresis current control strategy (HCCS) was introduced for high-power 20 kW brushless DC motor used in airborne integrated electrical hydrostatic actuator (EHA). In this control strategy, by the modeling of phase current using PWM_ON modulation mode and analysis of different types of current control strategy, a quasi-constant-frequency HCCS with simple implementation, inherited stability and over current protection capability was designed by improving the hybrid HCCS integrating the triangular carrier based control strategy and HCCS. Furthermore, completely constant-frequency was obtained by applying digitalized implementation and digital processing rules. Simulation and experiment show that this strategy can achieve constant switch frequency of power electric component and high frequency response of current loop in high power brushless DC motor simultaneously. This will provide a new approach for the high performance control of brushless DC motor.