A six-step three-phase inverter has an adjustable dc input. The load is a balanced Y connection with a series RL combination in each phase, with R = 5 Ω and L = 50 mH. The output frequency is to be varied between 30 and 60 Hz. (a) Determine the range of the dc input voltage required to maintain the fundamental-frequency component of current at 10 A rms. (b) Use PSpice to determine the THD of load current in each case. Determine the peak current and rms load current for each case.