Zero-Voltage-Switching Clamped Voltage DC/DC Buck Converter with SiC Power Devices

Inhalt:
In this paper a zero-voltage-switching clamped-voltage DC/DC buck converter is proposed. The circuit significantly reduces switching losses in the power devices and therefore allows higher switching frequencies. In addition the voltage slew rate can be limited to less than 10 kV/mus to prevent electromagnetic compatibility problems. This is necessary for fast switching devices like SiC-JFETs with dv/dt greater than 50 kV/mus. Drawbacks of the ZVS-CV converter are higher on-state losses. Dimensioning of the proposed circuit is discussed. A closed-loop control strategy is described and measured waveforms of an experimental test setup are presented.