传统上,在直流母线上安装大容量电解电容可有效吸收单相 AC-DC 变换器的二次脉动功率、降低直流电流或电压脉动.但电解电容存在体积大、寿命短等问题,有被可靠性更高的有源功率解耦取代的趋势.基于直流分裂电容的半桥解耦电路作为有源功率解耦拓扑的一种,独立运行于单相变换器,具有安装方便、应用灵活和反馈控制解耦精度高的特点.但相关研究均基于完全匹配的分裂电容进行分析,忽略了湿度和时间效应对于电容容值和功率解耦性能的影响.为提高解耦电路实际运行中的性能,对电容不匹配下的直流分裂电容进行分析,识别由此衍生出的直流和交流侧谐波的产生机理.以标准IEEE 1547?2003为谐波抑制目标,提出在分裂电容电压上引入直流偏置的谐波抑制准则和反馈控制,无需在线测量电容来识别电容漂移量,具有高解耦精度、高鲁棒性的特点.最后,以一台1kW实验样机对谐波抑制准则和功率解耦性能进行验证.%Traditionally, bulky electrolytic capacitors are commonly installed to buffer the inherent second order ripple power in single phase converter. However, electrolytic capacitor is marked as large volume, short life, and recently has the trend that be replaced by active power decoupling technology for the purpose of increasing reliability. One possible active power decoupling circuit consists of a half-bridge and two capacitors in series for forming a DC-split capacitor, which has flexible installation, independent operation and high precision decoupling. Methods for regulating this power decoupling circuit have earlier been developed, but almost always with equal capacitances assumed, leading to overlook the effects of timing progress, humidity and thermal on capacitance in real practice. To improve the power decoupling performance, this paper identified the harmonics resulting from realistic mismatched capacitance. As a result, harmonic suppression criterion and optimize control are then proposed without known online measuring real capacitance variation. Hence, the proposed method is thus robust and can meet requirement of standard IEEE 1547?2003. Finally,experimental results provided by a 1kW prototype converter have verified the harmonic suppression criterion and control scheme developed.
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