一种新颖的抑制两级式直交逆变器输入电流低频脉动的方法

A Novel Technique for Low Frequency Input Current Ripple Reduction In Two-stage DC-AC Inverter

两级式直交单相逆变器输入电流中含有两倍于逆变器输出频率的低频分量,这些低频分量幅值相对其平均值的比例很高,可达到30%以上,严重时将会影响直流电源系统的稳定性,也会大大影响输入电压源的蓄电池、燃料电池的使用寿命。通过研究该电流低频分量产生的原因,对前级直直变换器提出一种新的控制策略,即在传统的控制策略中引入谐振控制器,可以有效的抑制直直变换器输出滤波电感电流的低频脉动,进而可以有效抑制变换器低压侧输入电源电流低频脉动分量。给出谐振控制器的设计方法,以及引入谐振控制器之后系统各环路的传递函数,分析满足系统稳定性要求的设计准则。最后通过仿真和实验验证该控制策略对于抑制两级式直交逆变器输入电流低频脉动的有效性。

The input current of the two-stage DC-AC inverter contains low frequency ripple which is twice the inverter＇s output frequency.The proportion of the low frequency current ripple＇s amplitude to the average current is very high and it could be achieved more than 30%.The stability of DC power system and the longevity of the input voltage source such as battery or fuel cell could be influenced seriously.The new control strategy for the previous stage DC/DC converter was proposed by analyzing the reason of the low frequency current ripple production in this paper.The resonant controller is introduced in the traditional control strategy.The proposed new control strategy will be very useful to reduce the current ripple of output filter inductor in the DC/DC converter,and the input current ripple of the two-stage DC-AC inverter will also be lower.The design of the resonant controller and the transfer function of the system were given in the paper,and the design principles of system stability were also analyzed.At last,the effectiveness of proposed new control strategy to reduce the input current ripple which exists in the two-stage DC-AC inverter was verified by simulation and experimental results.