The utility model provides a voltage equalizing circuit for a five level converter, which relates to the field of power electronics. The four capacitors in the DC capacitor group II are connected in series to form a capacitor pair, and the five switch devices in the auxiliary mean voltage circuit I consist of the switch pairs in series; the positive end connection of the voltage sharing CAS includes the switch pairs composed of the switch device A2, and the negative end of the voltage sharing CAS is connected with the switch pair composed of the switch device A4; the capacitance CA1 is CA1. The positive end is connected to one end of the switch device A1, the negative end is connected to the other end of the switch device A1; the negative end of the capacitor CA4 is connected to one end of the switch device A6, and the positive end is connected to the other end of the switch device A6; the switch pair, including the switch device A2, is connected to the voltage sharing inductor LA1, the other end is connected with the negative end of the capacitance CA2; the switch is connected to the negative end of the capacitor CA2. The switch pair composed of the device A4 and the switch device A5 is connected to the voltage sharing inductor LA2, the other end is connected with the positive end of the capacitor CA3; the middle point of the two switch pair is connected to both ends of the voltage sharing capacitance CAS. One
【技术实现步骤摘要】
一种五电平变换器的均压电路
本技术涉及电力电子
,属于电力控制设备。
技术介绍
二极管箝位型五电平变换器利用4个串联的直流电容接在直流侧两端,同时,变换器每个桥臂的多个串联开关器件通过二极管连接在每个直流电容上,即通过二极管将开关器件的电压箝位到连接的一个直流电容电压上,将直流母线电压分为5个电平。因此,每个桥臂的多个开关器件在不同的开关组合下可向交流侧输出不同电平的电压信号。通过各种PWM(PulseWidthModulation,脉宽调制)调制方法,二极管箝位型五电平变换器将5个电平输出信号合成调制信号,电平数越多,变换器输出的交流电压越逼近调制信号。但是,在二级管箝位型五电平变换器中,各个电容器上输出不相等的功率将导致电容器上的电压不相等,即出现所谓的电容电压不平衡问题。通过优化的PWM调制方法,直流电容在一定条件下能够实现电压平衡与稳定,其平衡与稳定的条件与负载电流的相角有关。当五电平变换器传递纯有功电流时,即负载电流角度在0度附近时,为保证直流电压稳定,要求PWM调制深度最高且要求小于约55%,极大的限制二极管箝位型电路在有功传递领域的应用。直流电压失稳后,多电平变换器将退化成两电平变换器,同时失去多电平所具有的诸多优点,甚至影响变换器的自身安全。
技术实现思路
本技术的目的就是提供一种五电平变换器的均压电路,它能有效地解决在任意功率因数条件下,特别是在传递有功电流时,实现直流电容的电压均压与稳压的技术问题。本技术实现其的,所采用的技术方案是:一种五电平变换器直流电容均压电路,包括五电平变换器Ⅲ、直流电容器组Ⅱ和辅助均压电路Ⅰ构成,五电平变换器Ⅲ的 ...
【技术保护点】
1.一种五电平变换器的均压电路,包括五电平变换器Ⅲ、直流电容器组Ⅱ和辅助均压
【技术特征摘要】
1.一种五电平变换器的均压电路,包括五电平变换器Ⅲ、直流电容器组Ⅱ和辅助均压电路Ⅰ构成,五电平变换器Ⅲ的输入与直流电容器组Ⅱ输出相连,直流电容组Ⅱ中的电容CA1、电容CA2、电容CA3、电容CA4分别串联组成一组电容对,辅助均压电路Ⅰ中的开关器件A2、开关器件A3和开关器件A4、开关器件A5分别串联组成一组开关对;其特征在于,辅助均压电路Ⅰ由均压电容CAS、均压电感LA1、均压电感LA2和开关对构成;均压电容CAS的正端接开关器件A2、开关器件A3组成的开关对之间,均压电容CAS的负端接开关器件A4、开关器件A5组成的开关对之间;电容CA1的...
【专利技术属性】
技术研发人员:舒泽亮,李祖勇,毛文君,姚家煊,孟令辉,何晓琼,
申请(专利权)人:西南交通大学,
类型:新型
国别省市:四川,51
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