Power Conversion Systems Based On Power Electronics Network

Nowadays,power electronics trends toward system integration.Hence, modularization and standardization of the power application system are becoming important research topics.Therefore,investigation on the power conversion system based on real-time network(RT-Net) is critical for the system-level integration of complex and high-power converters.Thus,this dissertation focuses on the following topics:the model of power electronics system network(PES-Net),the communication requirements,a proposed real-time network structure,the distributed control and management,and the modularized software strategy.Finally,the dissertation presents a distributed real-time control structure,allowing the modularization and standardization process of the power conversion system based on RT-Net.The distributed control structure based on PES-Net is oriented to complex highpower conversion systems.First,from this kind of conversion system,the characteristic of space antithetic and the dual distributed for power and data flows are analyzed. According to the concept of power electronics building blocks(PEBB),a networked distributed control strategy is reviewed,and the building process of the application system is presented.In addition,the theory of standardization for complex power conversion system is summarized.Next,the model of the PES-Net is proposed.The field bus networks and the existing networks applied to power electronics are discussed.Also,the two types of networks are analytically compared in terms of structure,bandwidth,and protocol.The definition of PES-Net is clarified and,then,the network requirements for real-time control are analyzed.Based on the existing networks and related techniques,the model of PES-Net is presented.In order to achieve real-time control of power conversion system,the communication requirements of the network based distributed control structure is studied. The delay components of the conversion-system control are analyzed through the networked control system(NCS) concepts.The control functions and contents of the application system are summarized,and the response time requirements of the control tasks,located in different hierarchical level,are analyzed.According to the analysis of the simulation results,the control delay effect for every module and the delay limits the converter frequency are obtained.Since each application has different delay tolerances, the power converters of interest are classified into zero-delay system or fixed-delay system,and for each one the PES-Net capacitance and the switching period are obtained.The implementation and the synchronous scheme of the opened PES-Net are discussed.A novel real-time PES-Net(RT-PES-Net) and the integration of power conversion systems are proposed.The hardware construction of the opened PES-Net is presented according to the functional and structural requirement of master and slave node. The general design of the nodes is analyzed based on the interface analysis of the control system.In order to solve the synchronous problem in the PES-Net,a synchronous compensation method based on data frame is reviewed,and further a novel RT-PES-Net structure and its hardware construction are proposed.Then,the management of the proposed RT-PES-Net is analyzed,which includes a data frame supervision and its corresponding hardware configuration of different operation modes.The communication time of the operating mode is calculated and quantitatively compared.The integration method of application system of interest is proposed based on PEBB and real-time networks.Based on the real-time network,modularized software strategy is investigated. Firstly,the control software and the power hardware are decoupled,and the software design is separated from the hardware part.A modularized software architecture based on stack operation is proposed.According to the general principle of software components, interface parameters and variables are declared,and the corresponding addresses are configured,and the data is sealed in fixed-point.In order to build the standard real-time software library,the components are classified.The integration of power electronics system control software(PES-CS) is proposed,and simple software architecture is achieved.The components can be adapted to different application systems by properly configuring parameters and variables.Finally,the results of the real-time network system and the modularized software architecture for power conversion systems are implemented.According to the experimental results,the delay effect over the presented real-time network and the conventional network are compared,and the following advantages obtained:real-time control,switching frequency improvement,expandable ability,and flexible management. The application of the real-time network is implemented by applying to a full bridge converter,and the problems resulted from the communication delay can be effectively solved.The modularized software architecture,based on the general real-time control component(RTC) and the stack operation,is verified by experiments.The advantages of the software method are obtained,contributing to modularized software strategy and, consequently,to the system integration for power conversion systems.Networked control structure is critical for application integration of complex power conversion systems.This dissertation proposes a real-time network structure for power electronics systems,called RT-PES-Net.Based on the proposed network,distributed control structure,its network management and modularized software architecture are investigated.The thesis provides for a standardized,opened network structure for the control system of the oriented power conversion systems.The application system building process is proposed by using the RT-PES-Net,hence improving the spread process of power electronics standardization.This dissertation contributes to the implementation of "plug and play" and dynamic reconfiguration of complex power system,providing systematic design for the application integration.From the dissertation novel research topics in power electronics system integration and standardization can be further studied.