Fast time domain simulation of generic resonant mode power converter: Mapping the stability region

A macromodeling technique for generic resonant-mode power converters is described. This technique enables the transient and frequency analyses of resonant converters, embedded in their control circuitry, to be carried out some three orders of magnitude faster than by full component-level circuit simulation. This increase in speed enables `an analysis' to be treated as a primitive operation and allows more complex interactions of an entire system to be explored. The paper describes the technique, and demonstrates the power of the idea with a much higher level analysis; a resonant-mode converter controlled by a feedback system, driving a complex load. Like any physical system of this nature, there are combinations of system parameters that can cause overall instability (oscillation). In a power conversion environment, this can be extremely dangerous. The example shown uses a three-component load (R, L, C) and generates the `stability surface' in {R, L, C} space that separates the stable from the unstable regions of overall operation. This also demonstrates that the volume of `component space' enclosed by the stability surface decreases monotonically with increasing system phase margin.