New current source inverters with DC-side commutation and load-side energy recovery circuit

Two different thyristor-type current source inverters (CSIs) with DC-side commutation and load-side energy recovery circuit are proposed, with analyses and explanations of the circuit operation. The inverters overcome the major drawbacks of the conventional CSIs-high device voltage stress, low operating-frequency range, large commutation capacitance, etc.-by using a simultaneous recovery and commutation concept. They use only one commutation capacitor and can be built at very low cost. The commutation energies are temporarily stored in a large DC capacitor and recovered on the load side; thus the device voltage stress is low and the efficiency is high. Computer simulation results are given and compared with those for the autosequentially commutated inverter. Experimental results are given for 5 hp induction motor drive.<>