Reduced layer planar busbar for voltage source inverters

Planar busbars are used widely in modern high power inverters and have been shown to provide a good way for minimizing stray inductance and overshoot voltage. Planar busbars, which consist of multilayer copper sheets and dielectric insulators, offer significant advantages such as low impedance, improved thermal characteristic and reduced system cost compared with other interconnection approaches. A common problem of hard switched inverters is stray inductance, which needs to be minimized to reduce the effect of overvoltages. This paper presents a new physical structure for a voltage source inverter with symmetrical planar busbar structure, which minimizes the variation in stray inductance for different switching states. Three-dimensional (3-D) finite element simulations and experimental tests verify the theory