Digital Peak Current Program Mode Controller for Switched Reluctance Machines

This article proposes a digital peak current program mode control scheme for switched reluctance machine (SRM) drives. To control phase currents, in general, a hysteresis controller (HC) is widely used due to its simplicity and robustness. However, realizing HC on a digital platform requires a significantly high ratio of sampling to switching frequency. To obviate such steep demands on data sampling, the proposed scheme uses the precepts of the digital current program mode control, widely used for dc–dc converters. For amenability with the SRM drive, this article proposes a transformation that represents an SRM by its dc-equivalent circuit. This transformation also simplifies the mathematical modeling of the drive. Then, to consider variations in phase-inductance and back-emf, parameter adaption through real-time estimations is incorporated in the proposed scheme. A stability criterion is derived from the robustness analysis by probing the effect of estimation errors on reference tracking performance. Finally, the proposed scheme is experimentally validated using a 1 kW, 3000 r/min 6/4 SRM-based laboratory prototype. Also, the proposed scheme is bench-marked against the conventional HC and model predictive control scheme, realized on the same digital platform.