Research On Control Strategy Of Three Phase High Frequency Link Matrix Converter

With the wide application of inverter represented by solar cells and fuel cells,as well as the increasing demand for peak load and frequency regulation of power grid,inverter technology has been developed rapidly.High-frequency link matrix converter combines high frequency inverter technology with matrix converter topology,which has engaged a large number of scholars due to its excellent performance.However,the combination of the two technologies makes the existing modulation strategies for high-frequency inverter or matrix converter unable to meet the needs of high-frequency link matrix converter,and the narrow pulse in the switching signal will cause serious damage to the equipment under high-frequency conditions.Therefore,this paper focuses on the research of non narrow pulse control strategy for three-phase high frequency link matrix converter topology.In terms of modulation strategy,decoupling strategy is adopted to decouple the matrix converter into two anti-parallel main control switch groups.The half cycle is used as the modulation unit to form two groups of effective vectors which are symmetrical to each other and act on the corresponding main control switch group in the positive and negative half cycle.The six-section switching sequence of the whole modulation cycle is designed to form a six section SVPWM strategy that operates one switch at a time and eliminates narrow pulse.In order to reduce the requirement of the processor and facilitate the practical application,a dual modulation wave CBPWM strategy is proposed based on the proposed six stage SVPWM strategy.Based on the conduction time of each bridge arm switch and the six-sector division diagram,the expressions of two modulation waves for the whole modulation period are derived.Two modulated waves and carrier are modulated separately in the positive and negative half cycle,then the two half cycle modulation results can match each other.The two groups of modulated results are input into the logic circuit with flip-flop as the core component to calculate the switch signal without narrow pulse,and the four power switches of the same bridge arm carry out four step commutation according to the direction of output current,and finally complete the modulation.In terms of control strategy,the mathematical model of LC filter in rotating coordinate system is established,the feasibility of state feedback decoupling is analyzed,and the state feedback matrix is derived,which not only realizes decoupling control,but also improves the stability of the system.The regulator in the closed-loop decoupling strategy is designed,and the pole assignment method is used to adjust the parameters.Finally,the model is built on Matlab/Simulink software to verify the effectiveness of the proposed dual modulation wave CBPWM strategy based on six segment SVPWM.Under various operating conditions,the proposed strategy and traditional PWM strategy are simulated together.Through the analysis of the above simulation results,it fully proves the effectiveness and superiority of the proposed CBPWM strategy.