并网逆变器分数阶虚拟惯性的虚拟同步发电机控制技术

Virtual synchronous generator control technology with fractional virtual inertia for grid-connected inverters

传统虚拟同步发电机(VSG)控制策略在逆变器并网运行中为其提供了虚拟阻尼与惯性,增加了系统的频率和电压的支撑能力.然而,引入的虚拟惯性会增加系统的阶数,引起逆变器并网运行过程中输出有功功率的振荡,并且虚拟惯性与阻尼会使系统的响应速度变慢.对此,基于分数阶虚拟惯性环节的频域特性分析,提出一种分数阶虚拟惯性的虚拟同步发电机控制策略.与基于一阶惯性环节的VSG技术相比,基于分数阶虚拟惯性的VSG技术增加了可调参数,能显著抑制有功功率的振荡,全面改善并网逆变器的性能.仿真结果验证了所提出控制策略的可行性和优越性.

The traditional virtual synchronous generator(VSG)control strategy provides virtual damping and inertia in the grid-connected operation of the inverter,which increases the frequency and voltage support capability of the system.However,the introduced virtual inertia increases the order of the system,which will cause the output of the active power to oscillate during the grid-connected operation of the inverter;the introduced virtual inertia and damping make the response speed of the system slower.Based on the analysis of frequency domain characteristics of fractional virtual inertia link,a virtual synchronous generator control method with fractional virtual inertia is proposed.Compared with the traditional VSG technology based on the first order inertia element,the VSG control with fractional virtual inertia increases the adjustable parameters,significantly suppresses the oscillation of the active power,and improves the performance of the grid-connected inverters.Simulation results verify the feasibility and superiority of the proposed control strategy.