Energy Balance Control Of Power Electronic Converters And Its Application

The power electronic converter is widely applied to energy, communications, computers, home electronics and aerospace and other fields. With the constant expansion of application scope, the load is becoming more and more diversified. Good steady state and dynamic performances are required, especially the output tracking for electronic converters. Therefore,maintaining tracking of high degree of accuracy, desirable steady output and better dynamical performance is of great improtance which has become a hot topic. And with the development of the nonlinear control theory, adopting the nonlinear control theory of power electronic control system can highly improve the control performance of the converter, which is a significant theory with practical values.The study in this dissertation can be summarized as follows:(1) Based on the energy conservation principle of the physical field, the energy balance control equations of the power electronic converter topologies are derived. It keeps the balance between the energy that is injected into a circuit and the sum of the energy that is consumed by the load and stored in reactive components. According to the energy conservation analysis of the power electronic converter, an energy balance control(EBC) method, which is a nonlinear control method, is proposed.(2) Take buck converter as the research object. Firstly though the state analysis of the buck converter, the energy balance control equation of the buck converter is derived and the energy balance controller is designed. Secondly the stability of the converter with the energy balance control is proved using the Lyapunov stability criterion. Finally the dynamic performance of the converter with the energy balance control is analyzed. The research results show that the energy balance control method is superior to the customer control method in the static state and dynamic performances.(3) The nonlinear model of boost converter is estabilished. Firstly the possibility and attractiveness of the EBC method are futher verified. Secondly a current observer is designed to eliminate the using of the high frequency inductor voltage and current sensors. Then the implementation of the converter becomes simpler and less costly. Finally by transforming the energy balance control equation of the converter, an improved energy balance control(IEBC) method is proposed. The IEBC has better rubustness, which is independent of the parasitics elements of the non-ideal components in the circuit.(4) In view of the shoot-through problem of the conventional full-bridge inverter, the dual buck modulation method of full-bridge inverter is introduced. The modulation pattern resolves the shoot-through problem without increasing the complexity of the topological structure. Moreover, the modulation pattern also eliminates the DC offset and ripple wave of the output voltage of the full-bridge inverter using the control methods which need the reset integrator. And by introducing the EBC method, high-quality steady-state and dynamic responses are ensured from the inverter system.(5) With the rapid development of the high voltage, large capacity power electronic systems, multilevel power converter is becoming increasingly popular. A two-stage cascaded multilevel inverter topology, which has a simplified topology structure, is proposed in this paper.Reduction in the number of power switches along with the gate drivers is the remarkable advantage of the new multilevel inverter topology. As a result, the installation space and cost of the multilevel inverter are reduced. Meanwhile, the EBC method is introduced to control the new multilevel inverter, then the application of the EBC in more complex functions and topology power electronic converters is analyzed.In summary, the buck converter, boost converter, inverter and new multilevel inverter are took as the studing objects in this dissertation. Based on the energy conservation principle of the physical field, the energy conservation of the power electronic converter topologies are analyzed and the EBC and IEBC methods are proposed. This dissertation promotes the application of the nonlinear control theory in power electronic converter.