高频链结构独立光伏逆变器的研制

DEVELOPMENT OF INDEPENDENT PV INVERTER WITH HIGH-FREQUENCY LINK STRUCTURE

离网型独立光伏发电是太阳能利用的一种重要方式。为克服传统独立光伏发电逆变器采用工频变压器隔离升压所导致的其体积大、重量重、转换效率低等缺点,研制了一款高频链结构独立光伏逆变器,采用高频变压器实现电能传输和变换。针对低输入电压、中等功率高频光伏逆变器,为减小开关管电压、电流应力,提高效率,提出高频变压器初级并联、次级串联的组合推挽电路设计方案,并详细介绍关键电路参数设计过程。实验结果表明,所设计的逆变器输出电压稳定、正弦度良好、效率较高,功率等级和性能指标可满足大多数独立光伏电源的供电要求,具有广阔的市场应用前景。

Off-grid independent PV power generation is an important way of solar energy utilization. Traditional PV power generation employs the power frequency transformer to isolate and boost voltage, which leads to the shortcomings of big volume, heavy weight and low conversion efficiency. A stand-alone PV inverter with high-frequency chain structure was developed to overcome these shortcomings. Power transmission and transformation were realized by using high frequency transformer. In order to develop the low input voltage, medium power, high frequency PV inverter, a combination of push-pull circuit with primary parallel and secondary series high-frequency transformer was proposed to reduce the power switch voltage and current stress and improve the efficiency. The design process of key circuit parameters was described in detail. The experimental results show that the inverter can export stable voltage, has good sine degree and higher efficiency. The power level and performance index of the designed inverter can meet requirements of most independent PV power supply. The inverter has a wide application prospect of market.