Conversion Function Theory of Power Converter Systems

Modern power systems are increasingly relying on switching power converters to operate and control the power flow. This is mainly due to the need for power conditioning with the addition of new and diverse elements such as renewable energy sources and HVDC. These systems extensively utilize multiple types of power converters including DC-DC converters, AC-DC rectifiers, and DC/AC inverters. Moreover, power converters are used in a wide array of applications such as transportation (hybrid and electric vehicles, more electric aircraft, and more electric ship), motor drives, energy storage and management, and microgrids. This has led to complex structures which pose a challenge in terms of modelling and simulation. In this dissertation, the power conversion theory is presented: a general framework for modelling and simulation of systems with extensive presence of switching power converters. In this theory, power conversion functions are developed to represent power converters. These functions are defined based on the wanted quantity which corresponds to the application’s needs. Furthermore, a systematic approach to implement these functions with switching circuits is introduced. The theory presented here provides a method to refer one side of the converter to the other as an equivalent apparent element. This facilitates the reduction of a large system to a simplified circuit model. This model provides an intuitive insight into the operation and interaction between the components of the system. In addition, it offers a fast and accurate simulation approach for the study of the dynamics and performance of multiconverter systems. Furthermore, this theory can be extended to analyze multi-physics systems by employing the generalized gyrator theory, which allows the representation of elements in one physics domain with an equivalent element in another. Therefore, a multi-domain system can be analyzed in a single domain after all elements of the system are represented by their equivalent in the domain of interest