ISOP并网逆变器谐振环节频率自适应控制

Frequency-adaptive Control of Resonant Link in ISOP Grid-connected Inverter

两级式逆变架构在光伏并网、能馈式电子负载等领域应用广泛,在电网频率波动甚至宽频率范围应用时保证并网电流质量是工程应用中面临的实际挑战。针对电网频率波动引起并网电流畸变的问题,提出了谐振环节一体化频率自适应控制策略,消除了频率波动对并网电流总谐波畸变率(THD)的影响。同时,为了适应高电压高功率应用,采用多模块输入串联输出并联(ISOP)方法对能馈型电子负载进行集成扩容,基于模块ISOP均压均流原理与电子负载功能的特殊需求,提出了负载功能与均压均流独立实现的输入端主从控制法。最后,实验验证了所提方法的有效性。

Two-stage inverter architectures are widely used in grid-connected photovoltaics,energy-recycling electronic load and other fields.It is a practical challenge in engineering applications to ensure the quality of grid-connected current when the grid frequency fluctuates or even in wide frequency range applications.Aiming at the problem of grid-connected current distortion caused by grid frequency fluctuations,an integrated frequency-adaptive control strategy for the resonance link is proposed to eliminate the influence of frequency fluctuations on the grid-connected current total harmonic distortion(THD).At the same time,in order to adapt to high-voltage high-power applications,multimodule input series output parallel(ISOP)method is adopted to integrate and expand the energy-recycling electronic load,based on the module ISOP voltage equalization and current sharing principle and the special demand of electronic load function,a master-slave control method at the input terminal is proposed for load function realization,voltage equalization and current sharing.Finally,the effectiveness of the proposed method is verified by experiments.