Application of H∞ Control to Improve the Current and Speed Loops of Switched Reluctance Motor Drives

In this paper the H∞ robust control technique is applied to design a switched reluctance motor drive where the rotor position sensor provides just six pulses per revolution. A control system analyzer is used to obtain the frequency responses at each design step. To reduce the effect of the inherent phase inductance variations, an H∞ two-degree-of-freedom control scheme is designed in the current-loop of the drive to achieve the demanding time-response specifications. In order to have a good load torque disturbance rejection ability, the H∞ loop shaping procedure is employed to construct a lead-lag type controller in the speed-loop of the drive. The designed H∞ controllers are evaluated in real-time experiments with a digital signal processor (DSP). The results demonstrate the effectiveness of the proposed strategy in comparison with that of a conventional design.