DSP-based Discrete-Time Reaching Law Control of Switched Reluctance Motor

In this paper, a robust switched reluctance motor (SRM) drive using the speed closed-loop with the discrete time reaching law control and the current closed-loop with nonlinear conversion function from torque to average current is proposed. Firstly, the current closed-loop is implemented by employing the average value of three phase-currents and the digital proportion and integrator, which greatly simplifies the computational procedure. The nonlinear conversion function from the torque to the average current is obtained using experimental measures, which compensates the nonlinear characteristics between the average torque and current. And the discrete time reaching law control as an effective approach to sliding mode control is applied to the speed control of SRM drive, since the discrete time analysis and design are more appropriate for the digital control applications. The design equations are derived in the discrete time and the robustness of the control approach is analyzed. The experiments are carried out on a SRM drive consisting of 5 kW SRM and the DSP-based controller, and experimental results verify the proposed drive