Multiple frequency modeling of high frequency resonant inverter system

Multiple-frequency modeling (MFM) offers a general small signal modeling methodology for resonant type converters. A DC/AC resonant inverter is decomposed into two pure DC sub-circuits for each harmonics, the excitations of which are orthogonal. However, such decomposition makes the definitions of active power P, reactive power Q, apparent power S and instantaneous power p difficult, while these concepts are important for resonant inverter system power flow analysis and controller design. We extend the MFM by giving general definitions of P, Q and S in terms of the state variables of the series of decomposed sub-circuits of MFM. We present a general circuit model for high frequency DC/AC resonant inverter system. With this model, power flow analysis can be conveniently performed. Performances are analyzed in detail for a high frequency inverter-ac bus system.