Measurement of switching waveforms with a current sensor for a laminated bus bar

This paper proposes a method for improving the characteristic of the current sensor in a laminated bus bar. The current sensor is embedded in the laminated bus bar and is based on Rogowski coil. The stray components of the laminated bus bar and the sensor may affect the frequency characteristics of the current sensor. Therefore, it is difficult to measure the switching waveforms accurately with the sensor that uses conventional calculation methods. Firstly, the transfer function considering stray components, which is based on the geometry of the sensor, is analyzed in order to evaluate the frequency characteristics of the sensor. Then, the frequency characteristics are improved using an inverse function, which is derived from the transfer function of the sensor, and the inverse function is applied to the calculation method. Finally, the calculation method is verified by conducting a switching experiment, rated at 50V and 8 A. It is confirmed that the switching current waveforms that flow through the laminated bus bar can be detected more accurately using the sensor compared with commercial current sensors. © 2018 The Institute of Electrical Engineers of Japan.