具有选择性谐波补偿的光伏并网逆变器控制策略研究

具有有源电力滤波器APF(active power filter)功能的光伏并网逆变器因其高效率、高功率及可降低成本等优点而备受关注.当光伏阵列输出的能量较小时,可以利用逆变器的剩余容量进行谐波补偿,使系统工作在光伏并网和APF状态.但当系统负载谐波电流较大时,光伏并网和APF合成后的指令电流超过功率管的限流值,造成系...

Research on Control Strategy for Photovoltaic Grid-connected Inverter with Selective Harmonic Compensation

The photovoltaic(PV) grid-connected inverters with active power filter(APF) function have attracted much attention owning to their advantages such as high efficiency, high power rating and low cost. When the output power from the PV array is lower, the residual capacity of the inverter can be used to compensate harmonics, which makes the system work in the grid-connected and APF state. However, when the load harmonic current of the system is higher, the command current value obtained by synthesizing the PV grid-connected system and the APF will exceed the current-limiting value of the power tube, resulting in the system capacity exceeding its limit. To solve this problem, the shortage in the traditional proportional current-limiting mode is analyzed, and a control strategy for the PV grid-connected inverter with selective harmonic compensation is proposed, under which the selective compensation for the key harmonics of greater risk is carried out while the compensation for low-content and high-order harmonics is omitted, thereby reasonably reducing the synthesized command current and properly utilizing the limited system capacity. Finally, simulation and experimental results verified the feasibility and effectiveness of the proposed control strategy.