摘要
兼顾二次谐波电流抑制和动态性能改善是两级式逆变器中前级直流变换器的基本控制目标。该文从阻抗的观点出发,指出使前级直流变换器的闭环输出阻抗在二倍输出电压频率处呈现高阻抗,而在非二倍输出电压频率处呈现低阻抗是实现此控制目标的基本方法。采用与前级直流变换器的输出阻抗串联虚拟阻抗,并同时与中间母线电容并联虚拟阻抗的方法,实现了所提出的基本方法,并以Buck类的前级直流变换器为例,给出实现虚拟串联阻抗和虚拟并联阻抗的控制框图。通过对该控制框图进行等效变换,可推导得到现有文献中已提出的二次谐波电流抑制方法。最后,研制一台1 k VA原理样机,并通过理论分析和实验验证对这些不同控制方法的二次谐波电流抑制效果及对系统动态性能的改善作用进行对比。实验结果证明了理论分析的正确性。
A basic control objective for the front-end dc-dc converter in the two-stage inverter is to give considerations to both the second harmonic current（SHC） reduction and dynamic performance improvement. In this paper, a fundamental principle for the implementation of the basic control objective was proposed, indicating that the output impedance of the front-end dc-dc converter should be designed relatively high at twice the output voltage frequency while relatively low at other frequencies. According to the proposed principle, one virtual impedance was introduced to be in series with the original output impedance while the other one is in parallel with the intermediate dc bus capacitor. Taking the buck-derived front-end dc-dc converter as an example, the realization methods of the virtual impedance were presented, based on which, different control schemes in the previous publications can be synthesized. Finally, a 1 k VA prototype was fabricated in the lab and a comparative study was conducted on four different control schemes by both the theoretical analysis and experimental verification.
出处
《中国电机工程学报》
EI
CSCD
北大核心
2015年第3期660-670,共11页
Proceedings of the CSEE
基金
国家自然科学基金项目(50837003)
江苏省333高层次人才培养专项资助(BRA2012141)
中央高校基本科研业务费专项资金(YAH12012)
江苏省普通高校研究生科研创新计划项目(CXZZ13_0162)~~
关键词
两级式逆变器
前级直流变换器
二次谐波电流
闭环输出阻抗
虚拟阻抗
two-stage inverter
front-end DC-DC converter
second harmonic current
closed-loop output impedance
virtual impedance
