宽电压输入双接地单相非隔离光伏并网逆变器

针对现有双接地光伏逆变器在阴影条件下由于欠压而停机的问题,提出一种宽电压输入双接地单相非隔离光伏并网逆变器。该拓扑由升压单元和双接地逆变器构成,逆变器无共模漏电流,且在阴影条件仍能正常工作。采用多模态协同控制,减小逆变器各元器件的电压应力,并使得升压单元只需在欠压时工作,减少升压单元承受的功率,减小逆变器体积和重量;每个模态只有1个功率管高频开关,提高了逆变器的效率。详细分析拓扑构成、工作原理和控制策略。最后,搭建一台原理样机,验证理论分析。

Single-phase Double-grounded Transformer-less PV Grid-connected Inverter With Wide Input Voltage Range

A single-phase double-grounded transformerless PV grid-connected inverter with wide input voltage range was proposed aiming at the problem that the existing double-grounded PV inverter is stopped due to under-voltage in shading conditions.Since the topology consists of a Boost unit and a double-grounded inverter,it has no common mode leakage current and can operate under shading conditions.By using multi-modal cooperative control,the voltage stress of each component of the inverter was reduced.The Boost unit was only required to work when the input voltage is low.So,the power processed by the Boost unit was reduced.Therefore,the volume and weight of the inverter was reduced.Moreover,there is only one switch operating in high frequency at each mode,which increases the efficiency of the inverter.In addition,the topology composition,working principle and control strategy were analyzed in detail.At last,a prototype has been built to verify the theoretical analysis.