In: Electrical Engineering
a) A 50kW separately excited DC motor has armature resistance of 2.5W, armature inductance of 30mH and back e.m.f of 100V when the motor is fed from a buck converter with 250VDC input, 50Hz switching frequency and 50% duty cycle. Assuming continuous conduction and lossless converter, find out the maximum, minimum and ripple currents in armature.
b) Determine the values of inductor and filter capacitor for a buck converter with following specifications: Input= 48V, output = 24V, Load curernt = 6A, switching frequency = 20kHz, ripple current = 30%.