基于模型参数修正和有源阻尼的逆变系统并网控制策略

A Grid-Connected Control Strategy of Inverter System Based on Model Parameters Modification and Active Damping

为研究新能源发电逆变并网系统,以光伏系统为例,首先建立了光伏电池的数学模型,并且考虑实际情况加入修正补偿系数对光伏电池的数学模型进行修正,进而建立起光伏电池完整的仿真模型,研究在外界条件改变下的光伏电池的输出特性曲线,然后运用MPPT技术使光伏电池工作在最大输出功率处,最后采用了LCL滤波的并网逆变器进行并网.考虑到LCL滤波器的谐振和系统功率损耗的问题,提出了在并网电流直接反馈的基础上引入电容电流反馈的有源阻尼的控制算法,即对其采用基于PI控制的双电流环控制策略.仿真结果表明,仿真模型能顺利实现太阳能发电到并网的完整过程.

In order to research the grid-tie inverter(GTI)system of new energy generation,this paper takes the photovoltaic system as an example.Firstly,a mathematical model of the photovoltaic cell is established,and then the correction compensation coefficient is added to modify it,with the actual situation taken into consideration.Finally,a complete simulation model of the photovoltaic cell is established,and the output characteristic curve of the photovoltaic cell is studied under the change of the external boundary conditions.The MPPT technology is used to make the photovoltaic cell work at the maximum power point.At last,the LCL filter grid-connected inverter is used for grid connection.Considering the resonance of the LCL filter and the power loss of the system,an active damping control algorithm,i.e.a strategy of double current hysteresis control,based on the direct feedback of the grid current and the capacitor current feedback is proposed.The simulation results show that this simulation model can successfully realize the whole process from solar power generation to grid connection.