一种继电保护测试仪用逆变电源的设计及相位调节方法

Design and Phase Regulation Method of an Inverter System for Protection Relay Testing

该文主要讨论继电保护测试仪用逆变电源的设计及其相位的控制。结合单片机和正弦脉宽调制(sine pulse width modulation,SPWM)生成芯片,利用频率调节实现相位的闭环控制。该逆变电源可精确跟踪给定信号频率,并控制相位和幅度。与其他移相方式相比,利用频率调节相位的方法稳定性好,精度高,也比较容易实现。该文较为详细地说明频率调节的原理和数字实现方法。该电源频率的变化范围只需±0.05Hz,即可实现0°～360°间的移相,精度可达0.4°,稳定可靠。

To test different kinds of relays, an inverter system for protection relay testing was built; design of the system and close-loop phase control method were presented. Based on a micro-computer unit and a sine pulse width modulation （SPWM） control chip, an inverter which could accurately follow the frequency of a reference signal was discussed, whose phase and amplitude could be controlled. Frequency control was used to regulate the phase of the output voltage. Compared with other methods of phase regulation, this method is advantageous for the stability, accuracy and realization. Detailed principles and a digital realization method of the phase regulation were presented. A phase shift range of 0°～360° was achieved and the phase can be regulated within an accuracy of 0.4°, with the frequency variety range only ±0.05 Hz.