Accelerated commutation for passive clamp isolated boost converters

Abstract

This invention is an efficient and cost effective bi-directional DC/DC converter that can effectively reduce the switch voltage stress (such as a semiconductor) with an accelerated commutation circuit, and thus allowing a low-cost passive clamp circuit to be used. Specifically, the invention is a method and system to accelerate commutation for passive-clamped isolated boost converters, which can also be a boost mode in a bi-directional DC/DC converter. A primary circuit has a snubber comprising a diode, a capacitor and an energy dissipater (such as a resistor or small buck converter). The primary circuit can be a “full bridge converter” or a “push-pull converter” or an “L-type converter” configuration. The commutation of the present invention protects the primary circuit switches from voltage spikes during switching conditions. The present invention can shorten a secondary circuit by turning on at least two switches on the secondary circuit simultaneously for a minimal calibratable period while primary circuit diagonal switches turn off. The present invention also has a means to allow a smooth transition between a choke current and a primary current. Primary current increases linearly through the snubber circuit during circuit startup, thus protecting the primary circuit controllers.

Dependencies are inferred from the claim text.