The Research On500W Photovoltaic Independent/Grid-connected Dual Mode Inverters

The PV industry has been developing very rapidly in recent years because of the support from our government to the photovoltaic industry. In many parts of China, there are many photovoltaic power station constructed. In mountainous areas of the western area, many families are in a state of no electricity. However, these areas are generally located in higher, sunnier area and are very suitable for solar power generation.This topic designs a500W inverter which can work independently and grid-connected. The inverter can meet the electricity needs of a family when it runs independently. The inverter has grid-tied function. If there is grid laid to home, then the inverter can be connected to the grid.The whole composition of the inverter is introduced in detail in this paper. We choose atmega88of ATMEL Company and TI Company’s DSP chip-TMS320F28035as the control chip. Storage battery charging and discharging management and MPPT of photovoltaic (PV) power control is realized by using MOSFET. Inverter adopts two levels structure of main circuit. DC-DC boosting circuit adopts the push-pull topology structure circuit. The inverter circuit of the backward stage is composed of high power MOSFET, full bridge inverter circuit. The control signs are isolated from the after level inverter MOSFETs by opto-coupler. The SPWM signals which are used as control signals of inverter bridges can produce high quality sine waveform with less harmonic content.