中频逆变器数字控制延时的线性化近似

为了对逆变电源的控制系统进行准确设计,分析了数字控制延时对逆变器系统性能的影响,并采用Pade近似的方法对其进行近似。首先,给出了延时环节的1~4阶Pade近似,并对相关频率特性进行了比较,Pade阶数越高,近似越精确,但系统越复杂;然后,对一个单相400 Hz逆变器的控制系统进行了设计,采用比例谐振控制,通过对数字控制延时进行Pade近似,提出了考虑延时环节的比例谐振控制器设计方法;最后,通过实验对理论分析进行了验证。实验结果与理论分析相一致。

An Approximation Method of Digital Control Delay in Inverter

In order to accurately design control system of a inverter, impact of the delay induced by digital control on the inverter performances were analyzed,and the method of Pade approximation for the delay was present. The comparison of Frequency domain characteristic between the delay and its first to fourth pade approximation was implemented. The order of Pade approximation is higher, and the approximation is more accurate, but the system is more complex. The control parameters of a single phase inverter were designed by substituting the time delay with the Pade approximation when P+ resonant controller were adopted. The results are coincident with theoretical analysis.