采用滑模控制的复用型三相双频并网逆变器

Dual-function three-phase double-frequency grid-connected inverter adopted the sliding mode control

针对传统三相桥式并网逆变器开关损耗大且在附加谐波补偿功能后其谐波补偿容量受限制的问题,对三相双频并网逆变器的复用技术进行了研究,以改善这些问题。首先根据谐波补偿电流既可以从高频单元流过也可以从低频单元流过的特点,分析了三相双频并网逆变器的谐波补偿模式,并以此为基础设计了其并网发电和附加谐波补偿功能后的统一控制;由于三相双频并网逆变器的高频单元决定整个系统的动态和稳态性能,为了使整个系统具有很好的鲁棒性,进一步对其高频单元的滑模控制进行了研究。最后进行了仿真分析,仿真结果表明滑模控制下的复用型三相双频并网逆变器,在并网发电的同时能很好补偿电网谐波,并具有很好的动态和稳态性能。

Aiming at reducing the switching losses and broadening the harmonic compensation capacity, the three-phase double-frequency grid-connected inverter with harmonic compensation function is studied. According to the feature that the harmonic compensation current of the three-phase double-frequency grid- connected inverter can flow from high-frequency unit and low-frequency unit. The harmonic compensation mode of the three-phase double-frequency grid-connected inverter was analyzed firstly. Then the unified control for grid generation and the additional harmonic compensation function was designed. The high-fre- quency unit determines the dynamic and static performance of the entire system. To obtain good robust- ness, sliding mode control of high-frequency unit was studied. Simulation results show that the dual-func- tion three-phase double-frequency grid-connected inverter based on sliding mode control well compensates harmonics in the power grid in the grid generation time and has good dynamic and static performance.