Adjusting circuit parasitics to optimize converter switching transient behaviour

It is shown that the influence of parasitic energy storage in a physical converter circuit on converter operation can be modeled with equivalent lumped element circuits that allow SPICE simulations of complete converter circuits by inclusion of the equivalent circuits. The proposed techniques are demonstrated by an example, and the simulated results are verified experimentally. It is shown that the use of high-permittivity ceramic dielectric materials can significantly change the electromagnetic behavior of connecting structures. The concepts can be applied to practical structures and used to improve the converter behavior-for instance, by using the parasitic capacitance for snubbing. This obviates the need for discrete snubber components, leading to circuits with reduced component count, volume, and mass. The main advantage of the method is the significantly reduced switch stresses due to reduced overshoot and oscillation amplitudes. As a result, the switching device ratings can be reduced while maintaining circuit reliability