不平衡条件下基于改进准PIR逆变器控制研究  

Research on Grid-Connected Inverter Based on Improved PIR Controller Under Unbalanced Conditions

作　　者：徐海利[1] 李吉昌[2] 

机构地区：[1]福建电力职业技术学院自动化培训部,福建泉州362000 [2]积成电子股份有限公司电网自动化事业部,济南250100

出　　处：《控制工程》2017年第2期409-413,共5页Control Engineering of China

摘　　要：三相脉宽调制逆变器由于其具有低成本,高功率以及高灵活性在分布式发电系统中得到广泛应用。然而当逆变器在直流和交流母线之间,并网侧工作在不平衡电网条件下,上述优点无法获取。在不平衡条件下,提出一种新型准PIR控制策略实现三相并网逆变器控制。首先在不平衡条件下,推导了三相并网逆变器正序旋转坐标系平均模型。通过模型能够发现不平衡因素会产生负序环流。提出一种准PIR控制器,实现负序环流抑制。提出的控制策略能够有效的抑制环流,因此并网电流得到明显改善。仿真证明了所提方法的有效性。The three-phase pulse width modulation （PWM） inverter has been widely employed in distributed generation systems owing to its advanced features, such as high power, low cost and high flexibility. However, these features are not necessarily achieved when the inverters are directly connected between common DC and AC buses under generalized operating conditions of unbalanced grid supply. This paper proposes a new control scheme for PWM converters under generalized unbalanced operating conditions. An average model of the parallel system in the positive-sequence synchronous reference frame is derived to analyze the influence of generalized unbalanced operating conditions in the AC side. It is seen that the unbalance factors will give rise to negative-sequence circulating current. The negative-sequence circulating current can be inhibited by suppressing the negative-sequence components in AC output currents with a proportional integral resonant （PIR） controller. The proposed scheme can effectively suppress the negative-sequence circulating current and as a result, the distortions in output currents can be greatly reduced. Simulation results confirm the performance and effectiveness of the proposed method.

关 键 词：三相PWM逆变器 不平衡条件 负序环流 准PIR控制 

分 类 号：TM464[电气工程—电器]