Research On Power Data Dual-carrier DC-DC Converters

With the evolution of energy structure and system,Energy Internet has become the focus of research and development,which puts forward higher requirements for the integration of power and information.In order to comply with the trend of intelligence and meet the requirements of power information integrated,the information characteristics embedded in power electronics technology are combined with the power conversion based on the traditional power electronics technology,so that the power electronic converters modulated by the power data carrier are equipped with the ability of power conversion and information communication multiplexed in order to better serve the construction of Energy Internet.This dissertation takes the power data dual-carrier DC-DC converters as the research object,and conducts an in-depth study on its optimal modulation method,the characteristics of the DC system and its application.In order to reveal the connection between power conversion and information communication,the processes of their implementation are analyzed.It is concluded that the reorganization of the discrete electric energy in the power conversion process can achieve the effect of transmitting data information,and the mentioned reorganization can be realized by power data carrier modulation.The process and results of power data carrier modulation are explained and calculated in the time and frequency domains respectively,and the conclusion that power data carrier modulation can be used as an implementation method of power control and information communication multiplexing is obtained and verified experimentally.The power data dual-carrier modulation is optimized to improve the power conversion and information communication multiplexed capability of the DC-DC converter.The proposed Orthogonal Frequency Division Multiplexing-Multiple Quadrature Amplitude Modulation(OFDM-MQAM)technology with symbol combination zero-padding link enhances the power control and information communication multiplexed transmission,which means to optimize the power quality while increasing the communication rate.The proposed technology achieves the effect of transmitting high information content symbols in parallel by transmitting data information with multiple frequency carriers and using MQAM technology,and the communication rate is greatly improved.At the same time,the symbol combination zeropadding link is added in the data modulation to optimize the voltage ripple caused by data information transmission,which achieves the double improvement of communication rate and power quality.A new signal constellation diagram based on amplitude ratio/polarity is proposed to realize the multiplexed transmission under load change conditions.In addition,the frame format and demodulation links are designed to solve the problem of Inter-Channel Interference and Inter-Symbol Interference.The power control and information communication multiplexed methods of the AC-DC converters and Dual Active Bridge DC-DC converters are studied and proposed to provide full coverage of the power control and information communication multiplexed capability of the DC system.Then,the characteristics of multiplexed transmission for the DC system are analyzed.The relationship between the characteristics and the power characteristics of converters in the case of multiplexed transmission within micro DC system is obtained by ignoring the line impedance.The relationship among the characteristics of multiplexed transmission,the power characteristics of DC systems and transmission distance in the case of multiplexed transmission among the DC systems is obtained by equating the transmission lines as uniform transmission lines and combining different e-LAN structures.An operation state sensing method is proposed for a common bus DC system with power conversion and information communication capability composed of power data dual-carrier DCDC converters.The converters in the DC system are modulated by the power data dual-carrier during the same period of time according to the agreement,so that the voltage of DC bus contains components with the data carrier frequencies.Since these components have the fixed function with the state variables,circuit parameters and control parameters of each converter,the output current and power of the source converter,the load and input current of the load converter in the DC system can be calculated by using this function and the amplitude of the components with corresponding frequencies in the voltage of DC bus,thus achieving the purpose of sensing the operation state.A prototype of DC system consisting of DC-DC converters with power data dual-carrier modulation is designed.The DC system is able to correctly transmit and execute commands in the multiplexed transmission mode,and dispatch the power accurately.The experiments verify the feasibility of the power data dual-carrier DC-DC converters studied in this dissertation for the multiplexed transmission of power conversion and information communication.