Side-by-side 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 minimising stray inductance and overshoot voltage. Planar busbars, which consist of multi-layer 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 minimised to reduce the effect of overvoltages. This paper presents a new physical structure for a voltage source inverter with symmetrical planar busbar structure, which minimises the variation in stray inductance for different switching states. 3D finite element simulations and experimental tests verify the theory