2. A six-step three-phase inverter has adjustable de input. The load is a balanced Y connection with a series RL combination in each phase, with R 5Q and L 50 mH. The output frequency is varied between 30 to 60 Hz (a) Determine the de input voltage at 30 Hz to get fundamental-frequency component of current at 10 A ms. (b) Determine the de input voltage at 60 Hz to get fundamental-frequency component of current at 10 A ms. (c) Determine the range of the de input voltage required to maintain the fundamental-firequency component of current at 10 A rms