双端口矩阵变换器在工/低频电网互联下的电容及电压波动特性分析

Analysis of Capacitance and Voltage Fluctuation Characteristics of Two-port Matrix Converter Under Power/Low Frequency Interconnection

研究工/低频电网互联下双端口模块化多电平矩阵变换器的特性是实现变换系统轻型化设计的基础,同时也为变换器参数选定提供理论依据。首先分析了工/低频系统和变换器电压电流之间的关系,揭示了电容电压波动产生的机理;其次根据工/低频功率耦合下模块电容电压波动量提出电容值计算公式,指出电容的选定与工/低频系统电压幅值比、频率以及功率因数有着密不可分的联系;最后从经济性角度分析了工/低频系统电压幅值比以及频率对模块电容电压的影响,再从变换器稳定运行角度,探索两端系统功率因数与模块电容之间的关系。仿真计算验证了上述理论分析的正确性,分析结果可为实际工程中电容值的选取以及换流系统的设计提供理论基础。

Research on the characteristics of two-port modular multilevel matrix converter under power/low frequency interconnection is the basis of lightweight design of converter system, and also provides a theoretical basis for selection of converter parameters. Firstly, the relationship between voltage and current of power/low frequency system and converter is analyzed, and the mechanism of voltage fluctuation of capacitor is revealed. Secondly, according to the voltage fluctuation of module capacitor under power coupling of power/low frequency, a general formula calculating capacitance value is put forward, pointing out that selection of capacitance is closely related to voltage amplitude ratio, frequency and power factor of power/low frequency system. Finally, the influence of voltage amplitude ratio and frequency on module capacitor voltage is analyzed from economic point of view, and the relationship between power factor and module capacitance is explored from the point of system stability. Validity of the theoretical analysis is verified with simulation. The conclusion of this paper provides theoretical basis for selection of capacitance value and design of converter system.