A Hybrid State Space Model for Single Stage Three-Level Resonant Rectifiers.

This paper presents a state space model based on a combined averaging and multiple frequency models suitable for the prediction of the performance of a single stage three level resonant AC/DC converter operated with variable frequency asymmetrical pulse width modulation control or variable frequency phase shift modulation control to regulate the output voltage, shape the input current as well as to control the dc bus voltage. The pulse width modulation/phase shift modulation aims to regulate the input current shape as well as the level of the dc-bus voltage; whereas, the variable frequency provides a tightly regulated output voltage. This model is obtained by first deriving an average model of the switching converter, which is then analyzed to its frequency components. This results in substituting fast and slow oscillating values at steady state with variables that have a dc steady state value. This modeling approach is generally useful for variable frequency application and can be used at a detailed level that includes effect of parasitics, to a simplified linearized or a decoupled model to get steady state estimates of performance. The proposed model gives very good performance prediction under transient and steady state conditions and facilitates a better controller design. [ABSTRACT FROM AUTHOR]