1700 W Photovoltaic (pv) Grid Inverter Power System Design

Resently, the development of PV(photovoltaic) power generation project in this area of using renewable and clean energy is made great progress. And It becomes one of the most valuble apply research areas on the new energy resources. PV inverter is core of the PV power system and it’s divided into two directions:high-power large-scale centralized industrialization PV power generation and low-power small-scale decentralized domestic PV power generation, both for working more efficiently and steadily.The project objective this paper involved is developing a power system of a low power PV grid-connected inverter with transformer, in adition, the matching and interconnection between the control system and the power system will also be ensured, so that the function of PV inverter will be achieved completely. By this paper, firstly the simple and economical inverter topology which is easy to control is selected based on project metrics and budget. And according to the system function, the power system is divided into three major modules of the full-bridge circuit, the power supply and the auxiliary function circuit. And In the three modules, the full-bridge IGBT(insulated gate bipolar transistor) driver module is made of a easy and economical bootstrap circuit without the independent power, which save the production costs; aimed at the wide input of the sola panel, the power module uses a flyback switching power supply for efficient and low-cost to satisfy the multipath output need of system; the auxiliary function module is designed of the following modules:the DC/AC fliter circuit, which is used to ensuer the EMC preformence of system; the sample circuit used to real time feedback control and protection; the isolate ring industrial transformer with boost function. At last, we let the whole power system and the control system assemble to become the prototype and make sure it can run steadily and placidly. And the prototype has been modified and optimized after the performance test and data analysis.At present, the second edition of1700W PV grid-connected inverter prototype manufactured by thie paper has passed all acceptance tests and has higher work parameters and a low production cost, example for the maximal efficient92.49%,THD 1.2%and power factor l.They achieve the level of EU PV inverter. And it is runned stablely for two months in our lab, while it already makes over140kw/h power.