变频调速系统共模电流分析及其检测方法

变频调速系统中的复杂波形共模电流会影响传统电磁互感器的输出精度及线性度,导致测量结果存在较大误差。针对此问题,首先对系统共模电流的形成机理、流通路径与幅频特性进行分析;然后提出一种结构简单、宽测量范围的磁调制电流互感器,对互感器的检测原理进行了详细说明;最后进行了样机设计和试验验证。结果表明,所提出的磁调制互感器能够有效测量不同幅频特征的复杂波形电流信号,满足变频调速系统共模电流的测量要求。

Analysis and Detection Method of Common Mode Current in VariableFrequency Speed Regulation System

The complex waveform common mode current in variable frequency speed regulation system could affect the output accuracy and linearity of classical electromagnetic current sensor, which could result in the measurement error. Aiming at solving this problem, firstly analysis the formation mechanism, flow path and amplitudefrequency characteristics of common mode current, and then a magnetic modulation current sensor with simple structure and wide measurement range was proposed. The detection principle was described in details, and prototype design and experimental verification were conducted. The results indicated that the proposed sensor could measure complex waveform current, which could fulfill the requirements of common mode current detection.