基于分散逻辑的电子电力变压器并联控制技术

Parallel Operation Technology of EPT Based on Distributed Logic Control

为了解决电子电力变压器(EPT)并联时的均流控制问题,进一步提高电力系统的供电可靠性,提出了一种基于分散逻辑控制的交直流混合并联均流技术,分析了EPT并联的基本原理并分别介绍了其交流侧和直流侧的均流控制策略。分散逻辑控制的均流技术冗余性强、可靠性高、功能扩展容易,所提均流控制技术基于平均电流法原理实现瞬时均流,并联模块间仅通过一条均流信号总线交换信息,该方法通过单台EPT和所有并联的EPT所产生的电流误差信号调整参考电压的基准从而实现良好的均流特性。最后,在Matlab时域环境下对两台EPT交直流混合并联运行控制方案进行了仿真研究。结果表明,该方案在动态和静态过程中的均流效果都很好,并且具有良好的冗余特性。

An alternating current and direct current hybrid parallel operation technology of electronic power transformer based on distributed logic control is proposed, and the basic principle of electronic power transformer parallel is introduced. Current-sharing control schemes of the alternating current side and the direct current side are presented respectively, in order to resolve the problem of sharing-current control when several electronic power transformers are operated in parallel and improve power supply reliability of power system further. The parallel current-sharing technology based on distributed logic control is employed to offer several features such as better redundancy, improved reliability, better stability, flexible characteristic of function expanding. Current-sharing grounded on the average current method is realized by using a shared bus to connect all the paralleled modules without extra control modules. The proposed method maintains good current-sharing among the electronic power transformers by properly adjusting the voltage references of the electronic power transformers based on the differences between the average current of the paralleled electronic power transformers and the currents of the individual electronic power transformers. Finally, on the basis of the parallel system with two electronic power transformers, the alternating current and direct current hybrid parallel operation control strategy is discussed in detail and correlative simulations are carried out. The simulation results show the excellent current-sharing performance of the proposed parallel control strategy at both steady-state and dynamic operation and good redundant characteristic of the proposed parallel control scheme no matter alternating current side or direct current side. Therefore, the proposed alternating current and direct current hybrid parallel operation technology can resolve the problem of sharing-current control, and will improve power supply reliability of power system enormously due to good redundant characteristic both at the alternating current side and direct current side.