敏感用户高品质交-直流级联供电方案研究

Research on high-quality AC-DC cascade power supply scheme for sensitive users

工业过程中大量使用的变频器(variable frequency drive,VFD)在采用传统交流供电时易受到电压暂降影响,传统治理方式存在检测延时、控制复杂等问题。为此,该文从敏感负荷变频器在电网扰动工况下的供电需求量化出发,围绕供电拓扑设计、DC/DC变换器的控制策略及储能单元容量配置等方面,构建一种实用化工业用交-直流级联供电方案。该文利用电压暂降过程中直流供电回路与敏感负荷间的压差自感应控制,实现交-直流供电回路无扰动切换,提高电压暂降治理响应的快速性;采用两相交错并联DC/DC变换器接入集中式储能,减少储能系统纹波系数,并给出两相均流控制方法。最后,通过Matlab/Simulink中的建模仿真与样机的实验测试,验证所提方案能够在交流系统发生不同严重程度电压暂降过程中为各类敏感负荷提供稳定的连续供电,为解决工业敏感用户高品质供电问题提供可实用的新思路。

Variable frequency drive(VFD),which is widely used in industrial process,is easy to be affected by voltage sag when using AC power supply.The traditional control method has some problems such as detection delay and control complexity.Thus,based on the power demand quantification of VFD under grid disturbance conditions,a practical industrial AC-DC cascade power supply scheme has been constructed.The power supply topology design,DC/DC converter control strategy and energy storage unit capacity configuration has been put forward.This paper utilizes the voltage difference self-induction control between the DC power supply circuit and the sensitive load during voltage sag to realize the undisturbed switching between the AC and DC power supply circuits,improving the response speed of the voltage sag control.The centralized energy storage system interface to the power supply circuit by adopting two-phase interleaved DC/DC converter to reduce its ripple coefficient,and the two-phase current sharing control method is presented.The proposed power supply system is modelled and simulated in Matlab/Simulink,and the prototype is tested.The experimental results show that the proposed scheme can provide stable and continuous power supply for all kinds of sensitive loads during voltage sag with different severity in AC system,which provides a practical new idea for solving the problems of high-quality power supply for sensitive industrial users.