电能表检验台用标准电源新型逆变器

A Novel Standard Power Inverter for Electric Energy Meter Accuracy Testing Equipment

将新型逆变器应用于电能表检验台用标准电源设计以克服传统线性功放电路的缺点,提出一种由上、下两对称的Cuk变换器基本单元和双向开关组成的逆变器,并且在直流电源端并联大电容以提高逆变器感性驱动能力。逆变器采用正弦脉冲宽度调制(SPWM)技术,调制率取以0.5为中心;使用锁相技术对调制信号频率进行精确锁相并应用输出滤波电容器电流反馈内环和输出电压反馈外环构成输出电压双重反馈。分析和测试表明,该逆变器输出波形实现了平滑过零,波形失真度得到有效控制,输出电压频率、幅值稳定度较为理想。可达到电能表检验台装置对电压源的相应要求。

An inverter that consists of up and down symmetrical Cuk converters and bi-directional switches is proposed in this paper. The novel inverter is designed for the power of electric energy meter accuracy testing equipment to overcome the shortcomings of linear power amplifiers. The ability of inductance drive for inverter could be improved by connecting capacitance at the DC power ports in parallel. The inverter adoptes sine pulse width modulation （SPWM）, the modulation rate domain is set at the center of 0.5, the technology of phase locking is used to lock the frequency of modulation signals accurately and the output capacitance current and voltage to inner and outer feedback loops respectively are applied. Analysis and experiments show that such an inverter realizes output waveform to traverse zero smoothly, controls the waveform distortion effectively and gives the output waveform with satisfied stability of frequency and magnitude. The corresponding requirements of electric power testing equipment can be reached.