继电保护测试仪用大电流功率放大电路的研究

摘要

To meet the needs of high precision, high stability and high-power output for current amplifier used in the protective relay test device, this paper proposes a cost-effective design which takes the MSP430 microcontroller as control core. The hardware structure and operation principle are introduced at first, then the key technologies of the function realized including the direct digital frequency synthesis (DDS) and the digital PID incremental algorithm are analyzed in detail. Finally, validation test is conducted. The results show that the output current amplitude precision is 0.1%, stability degree reaches 0.1%, the frequency error is less than 0.001Hz and the load capacity is strong. In a word, this current amplifier satisfies the technical requirements of the protective relay test device.%　　为了满足继电保护测试仪用大电流功率放大电路在高精度、高稳定、大功率输出等方面的要求,给出一种以 MSP430单片机为控制核心的高性价比设计方案.介绍了电流功率放大电路的硬件结构及其工作原理,具体分析了其功能实现的关键技术,包括直接数字频率合成(DDS)、数字 PID增量算法等,对电路进行了相关试验.结果表明,输出电流幅值精度达到0.1%、稳定度达到0.1%、频率误差小于0.001 Hz,且电路带载能力强,可以满足继电保护测试仪对电流功率放大电路的技术要求.