Zhang Fang-hua

Modeling and analysis of a buck/boost bidirectional converter with developed PWM switch model

The aim of this paper is to provide a general method for bidirectional converter simulation and evaluation. A developed PWM switch model is proposed for bidirectional power flow application. A typical buck/boost bidirectional converter is chosen as a test bench for evaluation. Small signal analysis results show mode transition between battery charging and discharging modes. It provides a fast simulation tool to investigate steady and transient response of converters. The accuracy of the modeling technique is verified by a detailed comparison of simulated results with the developed PWM switch model and component circuit.

Modeling and Analysis of Hysteretic Current Mode Control Inverter

In this paper, a small signal model of hysteretic current mode control with variable frequency and fixed hysteretic band is presented, based on three terminal averaged switch cell of buck converter in continuous current mode. This model reveals that the averaged current is the control target of hysteretic control. And phase lag of current loop with high switching frequency is quite small that makes current loop equivalent power stage be a proportional component. The conclusion is also valid in large signal analysis. Then an averaged linear model of single phase inverter is derived. The order of the system closed loop characteristic equation is reduced due to hysteretic current control introduced. And compensation principles of a single phase inverter are investigated with Routh criterion, which is easy to implement in practice and a good comprise between stability and stable/dynamic performance could be achieved.