电子电力变压器与常规电力变压器的并联技术

Parallel Technology of Electronic Power Transformer and Conventional Power Transformer

在分析电子电力变压器(EPT)与常规电力变压器并联原理的基础上,提出将常规电力变压器的副方电压作为EPT输出电压的参考电压,以减少EPT与常规电力变压器并联时所产生的环流。在传统比例积分(PI)控制基础上提出了一种参考电压前馈的瞬时电压电流双闭环反馈的并联控制策略,并详细分析了其控制性能。理论分析表明,与常规PI控制策略相比,所提出的控制策略的稳态精度高、动态响应快捷。以单台EPT与单台常规电力变压器构成的并联系统为例,在MATLAB时域环境下进行了仿真研究,同时在基于数字信号处理器TMS320F2812所构建的试验系统中进行了试验验证。仿真和试验结果表明,所提出的常规控制策略获得了良好的均流调制特性,具有良好的动态响应特性,可实现不同容量EPT与常规电力变压器并联运行时的负荷合理分配。

In order to eliminate the circulation current resulted from the parallel operation between an electronic power transformer （EPT） and a conventional power transformer（CPT）, an idea that the secondary voltage of CPT is selected as the reference of EPT＇ s output voltage is proposed based on the analysis of parallel principle of an EPT and a CPT. A novel parallel control strategy on the basis of the proposed idea is presented and its control characteristic is also discussed in detail. The proposed strategy based on traditional proportional integration （PI） control consists of the reference voltage feed-forward, the instantaneous output voltage and the instantaneous capacitance current feedback loops. Theoretical analysis indicates that the proposed parallel control strategy has good steady-state accuracy and fast dynamic response compared with the traditional PI control strategy. A detail computer simulation with MATLAB/Simulink for the parallel operation of an EPT and a CPT is conducted, and this parallel system is also implemented in laboratory based on the digital signal processor （DSP） of TMS320F2812. Simulation and experimental results show that the proposed parallel control strategy has good current-sharing regulation characteristic and fast dynamic response, and achieves reasonable load distribution in the proposed parallel system with different ratings.