HERIC单相光伏并网逆变器无功调制及其直接功率控制

Reactive power injection modulation and direct power control strategy for HERIC single-phase grid-connected photovoltaic inverter

随着可再生能源在单相电网中渗透率的提高,电网对单相光伏并网逆变器提出了无功输出与功率因数灵活控制的要求。对HERIC(Highly Efficient and Reliable Inverter Concept)拓扑的无变压器隔离型单相光伏逆变器进行研究,提出了相应的无功调制策略。借助广义二阶积分构造两相静止坐标系,基于瞬时无功功率理论,建立了单相光伏逆变器的瞬时功率模型,实现了单相光伏逆变器的直接功率控制。搭建了5 k W的实验平台,通过实验对所提的调制策略与控制策略进行了有效性与实用性验证。

With the increasing of penetration level of renewable phase PV （PhotoVoltaic） inverters need to meet the demands of energy in single-phase grid, grid-connected single- reactive power compensation and flexible power fac- tor control. Firstly, the transformer-less isolated single-phase P~ inverters with HERIC （Highly Efficient and Reliable Inverter Concept） topology are studied, and the corresponding reactive power modulation strategy for HERIC inverters is proposed. Then,two-phase static coordinate system is constructed for single-phase PV inverter based on SOGI（Second-Order Generalized Integrator）. The instantaneous power model of single-phase PV inverters is estab- lished based on the instantaneous reactive theory, and a novel direct power control strategy for HERIC inverters is realized. Finally, experimental results with a 5 kW prototype validate the effectiveness and feasibility of the proposed reactive power modulation and direct power control strategy.