三相整流器并联运行环流抑制策略

摘要

整流器直接并联运行可以提高系统的可靠性和效率，减少成本，且易于模块化设计。但是整流器开关动作以及控制参数的不一致性会产生环流，导致整流器损耗增加，从而迫使整流器降低功率等级运行。控制环流是并联整流器设计的一个重要目标。本文以三相PWM整流器并联系统为例建立了环流的数学模型，针对环流问题，分析了影响环流大小的因素，验证了一个 PWM周期内零矢量分布的改变不会影响控制目标，并通过控制空间矢量脉宽调制（SVPWM）算法中零矢量在每个PWM周期中的作用时间对环流加以抑制。最后通过 Matlab仿真对本文的控制策略进行了验证。%The direct parallel of converters can improve the reliability and efficiency of the system, and reduce the costs,and it is convenient for modular design.But the switching motion and the inconsistency in control parameters may lead to circulation,whereby causing loss increase and force the converters to operate in a low level.For this reason,the control of circulating current is an important goal in the design of parallel converters.In this paper,the circulation mathematical model of three-phase PWM converter parallel system is established.Aimed at the problem of cir-culation,the factors affecting the size of circulation are analyzed.It is found out that the changes in zero vectors distribution in one PWM cycle will not affect control obj ectives.Controlling the operation time of zero vectors during every PWM cycle of space vector pulse width modulation (SVPWM)can suppress the circulating current.Finally,the effectiveness of control strategy is verified by Matlab simulations in this paper.