A fuzzy based speed controller for soft switched DC to DC converter fed DC servomotor for aero space applications

A new method of speed control of DC motors using pulse width modulation (PWM) based quasi-resonant (QR) zero voltage switching (ZVS) DC to DC converters is proposed. This control minimizes the switching losses, eliminates electromagnetic interference (EMI) and improves efficiency and commutation capability of the motor. The speed control is achieved by controlling the free wheeling period of the resonant inductor of a quasi-resonant converter (QRC). A half wave (HW) constant frequency (CF) ZVS converter exhibits a nonlinear relationship between its ON time and average output voltage. Hence, a fuzzy speed controller is designed to get better performance under load conditions. The software package PSPICE A/D is used for simulation.