DSP Based Sensorless PM DC Drives Using a Proportional plus Sliding Mode Control

This paper presents real-time implementation of sensorless PM DC drives. Original sliding mode controls (SMC) that integrate the inner current and outer speed loop controls do not perform satisfactorily alone, and so this study proposes to add a proportional control and feed-forward term to the SMC to increase the overall performance of the closed-loop system. This hybrid scheme may be called a ‘proportional plus sliding mode control’ (PSMC), and its main advantages are its ease of implementation, improved speed tracking performance and faster dynamic response. A stability analysis of the modified version of the closed-loop system is derived, and the validation of the proposed PSMC with a unified SM observer structures is verified by numeric simulation and hardware experiment. The performance of the PSMC scheme is compared with that of an original SMC and a conventional proportional plus integral (PI) cascade scheme, and the results are presented.