A Novel Capacitor-Switched Regenerative Snubber for DC/DC Boost Converters

Advanced transportation technologies, such as hybrid-electric, battery-electric, and hybrid-fuel-cell vehicles, rely on high-power dc/dc converters to interconnect and manage their power sources. Boost converters are particularly useful in stepping up the voltage from a battery or fuel cell to match the traction motor operating voltage range. High-frequency high-efficiency operation is crucial so that the sizes of the passive components can be reduced and fuel economy can be improved. This paper proposes a new regenerative-snubber circuit that greatly reduces the switching losses of the insulated-gate bipolar transistor in the boost converter, so that high-switching-frequency operation can be achieved. The circuit uses no additional magnetic components, enjoys a simple control strategy, and results in very high efficiency while significantly reducing the mass of the converter. Two 5-kW boost converter prototypes, i.e., one with and the other without the regenerative snubber, have been built and tested to evaluate and demonstrate the impact of the proposed snubber circuit.