基于Buck变换器的单相逆变器有源功率解耦控制策略

Active Power Decoupling Control Strategy of Single-phase Inverter Based on Buck Converter

单相光伏并网逆变器直流侧与交流侧功率不平衡会导致直流侧产生二倍频功率脉动,附加有源功率解耦(APD)电路虽可以有效抑制二次纹波,但由于附加了额外的元件,必然会导致单相逆变器的系统工作效率降低。对此,提出了一种基于Buck变换器的可以降低解耦电路功率损耗的控制策略,通过对解耦电路功率损耗的计算及其工作约束条件的分析,得到功率损耗与解耦电容平均电压值之间的关系,进而提出一种直接控制解耦电容平均电压的控制策略。仿真验证表明,所提控制策略有效抑制了直流侧电压纹波,并降低了解耦电路的功率损耗。

The power imbalance between DC side and AC side of single-phase grid-connected photovoltaic inverter leads to double frequency power pulsation on DC side.The additional active power decoupling circuit can effectively sup-press the secondary ripple,but due to the additional components,the system efficiency of single-phase inverter will be re-duced.Aiming at the above problems,this paper proposes a control strategy based on Buck converter that can reduce the power loss of decoupling circuit.By calculating the power loss of the decoupling circuit and analyzing the working con-straints,the relationship between the power loss and the average voltage of the decoupling capacitor was obtained,and then a control strategy to directly control the average voltage of the decoupling capacitor was proposed.Simulation results show that the proposed control strategy can effectively suppress the DC side voltage ripple and reduce the power loss of the decoupled circuit.