基于数字直接频率合成的B型剩余电流动作特性测试装置

Test equipment for type B residual current devices based on direct digital synthesizer

针对现有B型剩余电流动作特性测试装置适应性相对较弱的问题,对任意波形剩余电流动作特性测试技术进行了研究。在分析剩余电流动作保护电器测试要求的基础上,提出了一种基于直接数字合成(DDS)技术的B型剩余电流动作特性测试装置,该装置以DSP和FPGA为控制核心,采用数字直接频率合成技术产生了任意波形剩余电流信号,并用PID反馈控制方法实现了恒流输出。设计结果表明:剩余电流动作特性测试装置剩余电流频率范围可达1 k Hz,输出电流有效值达到30 A,满足相关标准要求。

Aiming at the issue of less adaptability of conventional test equipment for type B residual current device, a direct digital synthesizer (DDS) based test equipment was put forward according to the test requirement. Arbitrary waveforms of residual current could be generated accurately benefit from the well-designed DDS signal generator, which was controlled by DSP and FPGA microcontrollers. In order to stabilize the output current, a PID based feedback control strategy was introduced. The results indicate that the test equipment can output arbitrary residual current with a frequency bandwidth of 1 kHz ,and current range of 0~30 A, so as to meet the requirements of the relevant standards for residual current device.