Research On Single Stage Boost Inverter

As a core component of a renewable energy power generation system,the inverter plays a role in realizing power conversion and power transfer.Under the background of vigorously advocating the concept of green environmental protection and high efficiency,the inverter integration,power density,reliability and efficiency are very important.Based on the requirements of inverters for renewable energy power generation systems,this paper studies the circuit structure and steady-state characteristics of SSI(Split Source Inverter),which can boost voltage and conversion in a single stage.SSI inverter achieves step-up and inverter at the same stage through multiplexed switches,which has the advantages of fewer power devices,simple circuit structure,and high integration.This article first analyzes in detail the working principle and steady-state characteristics using hybrid SPWM modulation and unipolar frequency doubling SPWM modulation.Under hybrid SPWM modulation,the charging and discharging time of the boost inductor is unchanged,and the inductor current ripple is small,but the inverter modulation ratio is restricted by the DC boost duty cycle;Under unipolar frequency doubling SPWM modulation,only one variable to be controlled is the modulation ratio and over-modulation will not occur.The modulation is simpler,but inductor current ripple is much larger.Secondly,the closed-loop control strategy of the SSI inverter is analyzed,and a 500 W SSI inverter hardware experimental platform is designed and built.The drive circuit and device parameter calculation and selection are designed in detail.The theoretical analysis and its modulation strategy are verified by simulation and experiments.Finally,combined with renewable energy power generation applications that require higher voltage gain,an SSI inverter using switched inductors,switched inductor capacitors,and coupled inductors as boost units is proposed,and simulations and experiments are performed.Under the same input conditions,higher voltage gain can be obtained by using coupled inductor to boost voltage.