Steady State and Dynamic Response Analysis of a Chopper Controlled DC Separately Excited Motor

This paper describes a new method for evaluating the steady state and dynamic responses of a dc separately excited motor fed by load dependent chopper using time-ratio control (TRC). The proposed method takes into account the effect of commutation time and armature reaction. The area of armature current versus time characteristics during commutation interval is approximated by a trapezoid rather than a rectangle as in the constant current method. This method is applicable to both continuous and discontinuous current modes of operation. The results of this method are compared with those obtained from a digital computer by numerically solving the simultaneous differential equations valid for different intervals of chopper cycle, the constant current method and by experimental set up. The results show a close agreement with the exact solution by digital computer and experimental values.