| Renewable energies have became indispensable factors during the sustainable development of nowadays society along with the worsening of environmental pollution and the gradually exhausted non-renewable energy resources.New energy power generation has developed rapidly in recent years,expecially,the development of the inexhaustible solar energy has drawn great attention.Therefore,a single-stage DC-AC boost converter suit for PV is proposed based on the traditional inverter.Due to the buck character of traditional full bridge or half bridge inverter,the application condition will be limited in the photovoltaic power generation system.This thesis proposes a high gain and high efficiency single-stage DC-AC boost converter with a coupled inductor.First of all,the working modes and working principle of the proposed single stage DC-AC boost converter are analyzed detailedly under the power frequency and high frequency cycle,besides,the voltage stresses of power devices,the bus capacitor loss and the steady-state voltage gain of the converter are calculated.Secondly,an unipolar SPWM modulation for the single-stage DC-AC boost converter is studied in this paper.The power switches states of the converter are controlled by the modulation to achieve the function of boosting and inverting simultaneously.Then,The hardware of the whole system is designed,besides,the main program,the interrupt program,the PID control program and their program flow charts are supplied.Finally,the simulation model of the proposed converter is built on the Matlab/Simulink platform,and the theoretical analysises are verified by the simulation results.One 1kW experimental prototype is built in,and the correctness of the theoretical analysis and the feasibility are proved. |
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