单相H桥光伏逆变器的混沌控制

Chaotic control of a single-phase H-bridge PV inverter

逆变器是强的非线性系统,它通常具有复杂动力学现象,例如跨临界分岔、倍周期分岔等,它会大大增加输出电流的谐波含量,降低变换器的效率,使其发生振荡乃至崩溃。目前大多数混沌控制存在建模困难、控制效果不明显、稳定性不强的缺点。针对此,提供了一种全新的混沌抑制方式,即改进余弦延时反馈控制(improved cosine delay feedback control, ICDFC)。该方式先使用被控对象的输出量和自身延时一个周期的差值作为反馈量,该反馈量再经过余弦函数环节和反馈控制参数之后得到控制信号,并将该控制信息以反馈形式直接作用到被控对象中。同时构建系统频闪映射模型并寻求系统的Jacobian矩阵和平衡点,最后基于朱里判据给出了反馈控制参数的限定条件。为说明所提出混沌控制方法的优越性,开展了大量的仿真模拟试验,并与指数延时反馈控制进行比较。结果表明,ICDFC能更有效地抑制逆变器的混沌行为,且大大增加了系统运行的稳定域。

The inverter is a strong nonlinear system.It generally has sophisticated nonlinear dynamical behaviors,for instance transcritical bifurcation,period doubling bifurcation,etc.It will greatly enhance the harmonic components of the output current,decrease the efficiency rate of the convertor,make it oscillate and even collapse.At present,most of chaos control methods has the disadvantages of modeling difficulty,not obvious control effect and not strong stability.Aiming at this,a new chaos suppression method,namely improved cosine delay feedback control(ICDFC),was proposed.In the method,the difference between the output values of the variable of the controlled object at this time and at the time of one period delay was used as the feedback quantity,and then through the Links of cosine function and feedback control parameters,the controlling signal was achieved.Thereafter,the controlling message directly reacted on the controlled subject in feedback form.In the meantime,the system's stroboscopic mapping model,was established and the Jacobin matrices and balance points of the controlled object were obtained.At last,the restrictive conditions of the feedback controlling parameter were presented based on the July criterion.To illustrate the superiority of the suggested chaotic control method,a great deal of simulating experiments were unfolded,and compared with the exponential delayed feedback control,which proves that ICDFC can not only suppress the chaotic behavior of the inverter more effectively,but also greatly increase the system operational stable region.