Research Of Three Phase Micro-inverter Based On Full-Bridge LLC Multi-Resonant Converter

Energy is the basis of production and life of human society,but the massive use of fossil fuels brings a series of environmental problems.With wind energy and solar energy based new energy power generation,due to its widespread,renewable and non-pollution,is gradually becoming a substitute of fossil energy,and also providing a new way for the world to solve the environmental pollution and energy shortage problems.With the increasing application of micro inverter in commercial field s,three-phase micro inverters are more and more developed due to their unique advantages,such as high power generation efficiency,three-phase power balance and so on.Two-stage three-phase micro inverters in the distributed new energy power generation as the object researched in this paper,and we mainly discuss the control optimization of the inverter.First of all,establish the mathematical model of the inverter system in different coordinate system is established by mathematical calculation.In view of the traditional PI control can't solve problem of the output current of the inverter static error and parameter set difficult,the overshoot of the system is too large,elaborating a deadbeat control strategy based on direct power control,in order to solve the MCU in the control and sampling of the delay effect.The DC/DC boost in this subject is the full bridge LLC multi resonant converter,the advantages of this converter is achieving soft switching in high gain in the whole load range and can greatly reduce the switching losses of the boosting process,so as to improve the conversion efficiency of the whole system.The DC/AC inverter in the stage uses software PLL rather than hardware PLL phase-locked,pointed out the shortages of zero phase locked loop under complex power grid conditions,expounding the general structure and working principle of dual two order generalized integral based on phase locked loop,aiming at its shortcomings and making optimization.Simulation model of three-phase inverter system is established in the Matlab/Simulink software to verify the deadbeat theory.The experimental prototype is built,and the hardware circuit design of the inverter system is described in detail,including the layout of the main circuit.Use TI high-performance DSP processing chip TMS320F28035 as the experimental prototype of the control chip.Achieving the current deadbeat control and SVPWM modulation,and ultimately proved the feasibility of the system.