Energy And Signal Synchronous Transmission Strategy For Srm Loaded Distributed Switching Power Supply System

Distributed switching power system?DSPS?has the advantages of simple structure,high efficiency,convenient operation,high reliability and so on.It is widely used in power system,new energy vehicles and other fields.At present,the development demand of distributed switching power supply system is to combine information with energy,so as to reasonably utilize and allocate energy flow.For distributed switching power supply system with cascade load of traditional boost converter and switched reluctance motor?SRM?power converter,three new synchronous energy and signal transmission strategies are studied in this paper,and are verified by simulation and experiment.Firstly,the basic principle and control method of switched reluctance motor speed control system are analyzed.Combined with the turn-off angle(?_off),one of SRM control parameters,a signal modulation strategy with variable turn-off angles is proposed.By adjusting the magnitude of?_off,voltage ripple with specific frequency components can be induced on the power bus,and signal transmission can be realized by taking the voltage ripple as a carrier.Based on the linear model,the expressions of commutation ripple,Boost switching ripple and SRM converter switching ripple are derived,and the approximate relationship between ripple size and turn-off angle,frequency and rotational speed is obtained.Based on flux linkage-current??-i?trajectory diagram,the difference of DC component of bus ripple under different?_offis analyzed,which provides basis for signal modulation and demodulation.Secondly,in order to reduce the influence of signal modulation on SRM load operation characteristics,according to the difference of soft and hard chopping modes of SRM in freewheel section,a freewheel section FSK modulation strategy is proposed.The lower switch tube is opened at the excitation section to control and drive the upper tube for speed regulation.Turn off the upper tube in the freewheel section and modulate the signal of the lower tube.For any phase of SRM with 8/6structure,there are four operating modes in one cycle.By analyzing these four operating modes,a speed control method suitable for SRM is found.Under this modulation strategy,the communication rate is not affected by the motor speed and the transmission efficiency is greatly improved.Thirdly,considering the problem of various interferences when signals are transmitted on the power bus,a freewheel phase shift keying modulation strategy based on direct sequence spread spectrum?DSSS?is studied to improve the anti-interference capability of the system.This paper introduces the generation mode and relevant characteristics of m sequence,and expounds the principle of modulation and demodulation methods of the system.Finally,a Boost-SRM cascade system simulation model is built in Matlab/Simulink software to verify the feasibility of the three energy/signal synchronous transmission strategies.Under the support of simulation research,an experimental verification platform was built to verify the effectiveness of the three strategies.This thesis has 85 figures,3 tables and 94 references.