Snubber-Assisted Zero-Voltage and Zero-Current Transition Bilateral Buck and Boost Chopper for EV Drive Application and Test Evaluation at 25 kW

A new high-efficiency and high-power bilateral buck and boost chopper circuit for the electric-vehicle drive application is presented. The operation principle of snubber-assisted zero-voltage and zero-current transition (SAZZ) topology was applied, and a new SAZZ bilateral buck-boost chopper circuit (SAZZ-1) was created by combining two basic SAZZ circuit types. A 50-kHz 25-kW SAZZ-1 was fabricated and tested. An efficiency of 96.6% at 25 kW with boost mode (input: 250 V/output: 390 V) in forward direction and an efficiency of 97.4% at 25 kW with buck mode (input: 420 V/output: 300 V) in forward direction were obtained. The high potentiality of the SAZZ-1 chopper is demonstrated as we expected.