基于自抗扰技术的Z源逆变器并网控制研究

Z-source inverter grid-connected control based on active disturbances rejected control strategy

在永磁同步直驱风力发电Z源逆变器并网系统中,对Z源逆变器采用电容电压外环和电流内环的双闭环控制。针对Z源逆变器中电容的启动冲击电压过高问题,在电容电压外环中引入自抗扰控制算法,设计了自抗扰控制器,以稳定启动时的电容电压;将基于自抗扰控制的Z源逆变器与LCL滤波器结合,由滤波电容电流和网侧并网电流构成的电流内环采用PI算法,以降低并网电流谐波畸变率,改善并网电流质量;通过控制直通零矢量对永磁同步发电机的转速进行调节,以实现风力发电最大功率跟踪。仿真实验验证了方法的可行性和有效性。

In Z-source inverter grid-connected system of the direct-drive permanent magnet synchronous generator, the double loop control of outer voltage loop and inner current loop is adopted to control the Z-source inverter. In order to stabilize the start-up voltage capacitor, by using Active Disturbances Rejected Control(ADRC) strategy in outer voltage loop and introducing the Active Disturbances Rejected Controller, the start impact of the Z-source capacitor voltage is optimized. Meanwhile, by using LCL filter in this system, and using filter capacitor current and filter inductor current duel loop to control the inverter, the total harmonic distortion rate of grid-connected current is reduced and the grid-connected current quality is improved. The speed of generator is controlled by short-through duty cycle to achieve maximum power point tracking(MPPT). Finally, a simulation experiment is carried out and the simulation result shows the feasibility of proposed control strategy.