基于谐波理论和Cotex-M3的数字式相位差测量系统设计

The Design of Digital Phase Difference Measurement System Based on Harmonic Theory and Cotex-M3

摘要:

相位差测量在故障诊断、线性系统动态特性分析、电工领域中的相关参数测量等实际工程项目上的应用具有重要意义。该文根据频率相同的周期变化信号相位差等于两信号初相差这一基本原则,设计一种通过计算同频周期信号初相结合DFT非整数修正算法的相位差测量系统。系统采用Cortex-M3内核的新一代32位ARM微处理器为核心设计完整的系统架构,对系统进行控制和数据处理,利用TI公司的工程应用级别的程序库和DSP算法库实现准同步DFT非整数修正算法,结合据牛顿迭代算法和相位差与初相的关系计算出信号实际相位差。实际测试结果显示,系统对相位差的测量精度高,最小测量精度可达0.1°,并实现宽频率范围的相位差测量,在实际应用中测量结果准确、稳定、可靠。

Abstract:

【】The phase difference measurement takes an important role in fault diagnosis, dynamic characteristic analysis of linear system and some relative parameter measurements in electrical engineering field. In this paper, according to the principle, the phase difference for same cycle frequency signals is equal to the initial phase, a phase difference measurement is designed by calculating the initial phase of same cycle frequency signals, and combined with DFT non-integer correction algorithm. The system adopts a new generation of 32-bit ARM microprocessor based on cortex-M3 to design a complete system architecture for controlling and data processing. Besides, by using the engineering library of TI Company and DSP arithmetic library, the quasi-synchronous DFT non-integer correction algorithm can be realized, and based on Newton"s iterative algorithm and the relationship between phase difference and initial phase, the real phase difference can be calculated. After some tests, the results show that the system has a high accuracy of phase difference, and the minimum measurement precision can reach only 0.1°. At the same time, the wide frequency range is also suitable for phase difference measurement, which is accurate, stable and reliable in application.