Development of transformerless 5 kW bidirectional inverter in PT. Len Industri

The development of transformerless 5 kW grid connected/offline bidirectional inverter simulation in PT. Len Industri is reported. The aim of transformerless is to reduce total cost and losses; making it more suitable for remote area application. The bidirectional inverter consist of two stage: bi-directional multiphase dc - dc converter and single phase inverter. Double PI control loop is used in dc - dc converter; controlling dc-link voltage in outer loop and ensuring balance of each phase current in inner loop. Single phase inverter also uses double loop control: unbalance dq to control inverter voltage in its outer loop and PI to control inductor current in its inner loop. The simulation run in PSIM and successfully conducted in stand alone (battery discharge), battery charge, and transition mode.