并离网逆变器的控制研究

Research on Control Algorithm Based on On-line and Off-line Inverters

研究了一种既能够工作在并网,也能工作在离网状态的逆变器.在市电异常时,并网逆变器能够可靠地切换到离网模态保证本地重要负载供电.重点分析了工作在离网模式下的控制策略及切换方法,通过电感电流无差拍内环控制来实现输出输入电压与电流内环的扰动作用,提高了内环的跟踪速度.在离散域下分析了无差拍模型电感参数的匹配范围,针对数字控制延时降低了模型电感参数匹配范围并引起系统稳定裕度变小的问题,提出了改进型的无差拍电流内环控制,提高了系统的稳定裕度.最后通过实验证明了该控制算法的可行性和优越性,以及适合设计的切换要求.

The paper introduces an on-line inverter, which can also be used as an off-line inverter when the grid is abnormal. This paper mainly proposes an instantaneous dual-loop control algo- rithm based on deadbeat current inner-loop for single phase off grid inverters. The deadbeat con- trol of inductor current is adopted to eliminate or weaken the disturbance induced by the out and input voltage, which improves the tracking speed of inner-loop. By applying the z-transformation technique, the stability margin and the matching range between the deadbeat model inductance and actual inductance is proved to be reduced when the control delay exists. To solve the problem, an improved deadbeat control algorithm is proposed. Finally, the validity of the proposed algorithm is demonstrated by means of simulation and experimental results from a single-phase inverter.