Research On Single Phase Inverter Based On Boundary Conduction Mode

The inverter,which is the interface device of the distributed power and the grid,is of great significance to the photovoltaic system.When the full bridge inverter operates in the boundary conduction mode(BCM),the high-frequency MOSFETs possess the advantages of ZVS.But the peak value and the current ripple are large,which result in some problems.By parallel interleaving,the peak value of each branch and the output current ripple can be reduced effectively,which reduces the EMI.In this paper,the interleaving BCM inverter is studied to inprove the performance.This paper firstly brieflies the research status of high-performance inverters to point out the significance and contents of this project.In this paper,the BCM inverter is selected as the main control strategy.The soft switching characteristic and the switching frequency characteristic of BCM inverter are analyzed.According to the difference of the comparison between the inductance current and the sinusoidal reference current,two methods of BCM inverter are given.The advantages and disadvantages of the two methods are analyzed and compared,and the effect of the control delay on the output current waveform is analyzed.The parallel interleaved control method is proposed for the large current stress and the large ripple of BCM inverter,and the effect is analyzed quantitatively.As the switching frequency of BCM inverter is changing,the simple constant frequency phase-shifting control method can not be adopted.In this paper,several common frequency conversion interleaving methods are introduced,including open-loop interleaving control and closed-loop interleaving control.The application effect is analyzed and compared,including the influence of the mismatch of the inductance and the effect of one-time error on the stability of the system.Finally,the validity and advantages of the parallel interleaved method are verified by simulation.Finally,the main circuit parameters of 2kW interleaving BCM inverter are calculated.The control strategy is implemented by using TI control chip 28035 and the key techniques is given.The related experiment results verify the analyse above.