光伏并网逆变器无线并联控制技术

Control technology of inverters wireless parallel operation in photovoltaic grid-connected system

为了提高无线并联光伏逆变器系统的稳态均流精度和动态响应能力,基于改进的下垂法和正弦波三要素功率计算法,建立了用于逆变器无线并联的新型多环控制系统。改进的下垂法考虑到有功功率和无功功率对电压幅值和相位的影响,并引入了有功功率、无功功率的微分项。同时,无积分单元的正弦波三要素功率计算方法的采用,既保证了系统的稳态特性又改善了动态特性。仿真结果表明,该系统动态响应快、稳态性能好,并具有很好的功率均分性能和环流抑制能力。

To improve power sharing accuracy and the dynamic response ability of photovoltaic wireless parallel inverters, based on an improved droop algorithm, a novel multiple-loop controller was developed. In this algorithm, every droop expression considered both of effects on voltage amplitude and phase, from the active power and reactive power signals. And the differential signals of active power and reactive power were included. Besides, the adoption of sinusoidal signal three-elements power calculation method without integral unit not only ensured the steady characteristics of the system, but also improved the dynamic characteristics. Simulation results indicate that the system has good dynamic and steady state performances, and the power sharing and circulating current restraining performances are also satisfactory.