Robust speed control of a switched reluctance vector drive using variable structure approach

Robust speed control of a switched reluctance vector drive is presented in this paper, An approximate sliding-mode input power controller and another feedforward sliding-mode speed controller are combined with space voltage vector modulation. The resultant drive has rapid and robust speed response, In addition, a switched reluctance drive incorporating the proposed controller requires only one current sensor and can be implemented in a low-cost 8-bit microcomputer and a few discrete integrated circuits, Furthermore, the controller does not require any off-line characterization of the motor or load characteristics and could easily be applied to switched reluctance motors with any number of phase windings. A 4-kW four-phase switched reluctance drive is constructed to test the performance of the controller, The results show that a step response From 200 to 1980 r/min needs only 2-3 s, even when driving a high-inertia load, and that the speed error can be controlled below 1%, even under unknown and dynamic loads. It is concluded that modified sliding-mode controllers are effective in dealing with the highly nonlinear characteristics of the switched reluctance drive system.