Research On Novel PV Inverter Circuit Topology And Control Strategy

In the PV systems, the design of the inverter is the key, the level of its efficiency, reliability and quality will directly affect the whole network system performance. In this paper, the traditional small and medium sized PV system topology and configuration of several programs were compared, and found that boost and inverter two links were included in the traditional small and medium sized PV system , there were high cost, size and weight, control complexity, reduced reliability.There are PV systems control objectives: Control the inverter output AC voltage (current) to stabilize the quality of the sine wave, the same frequency and phase as the grid voltage. However, the PV array DC output voltage is low (typically 48V), in order to achieve networks, boost is needed, thus the difficulty of control, costs, and the low utilization rate of DC voltage are increased.Can boost and inverter be completed in one circuit? By some analysis of grid-connected inverter currently used, according to AC Chopper principle, based on results of DC chopper circuit topology, a new Dual-Boost DC-AC inverter circuit as PV system were proposed, the output voltage and frequency regulation can be adjusted, the voltage transfer ratio can be very higher.The problem of low voltage DC output in PV array is effectively solved; inverter and boost were completed in one circuit, reducing the difficulty of the control and cost savings. By the topology research , the program of the main circuit and circuit parameters are determined. The effective control strategy are studied for the new circuit ; variations between the net output of the waveform total harmonic distortion and other key performance indicator are studied . The simulation model were set up , some prototype were produced .Simulation and prototype results show that: Boost performance of original boost still be maintained, the double-Boost DC-AC inverter has a very high voltage transfer ratio, low total harmonic distortion, this method is a new develop prospects for the PV system .