Extended Wide-Bandwidth Rogowski Current Sensor With PCB Coil and Electronic Characteristic Shaper

Abstract

Because of their fast switching speeds, current measurements for wide band-gap (WBG) devices have become increasingly challenging. Particularly, the designed current sensor must be nonintrusive and have a small size and a very wide bandwidth. One promising current sensor is the printed-circuitboard (PCB) Rogowski current sensor, whose bandwidth is wide only if parasitic parameters of its measuring coil are minimized prominently. This is presently achieved by reducing the number of turns of the coil, which undesirably will degrade its signal-to-noise ratio. Alternatively, an electronic characteristic shaper proposed in this letter can be used for neutralizing parasitic effects, while performing integration to restore the measured current. Theoretical analyses and experimental results have shown that the resulting Rogowski current sensor does indeed have a wider bandwidth, even without changing its measuring coil.

Signal Processing Design for Wide Bandwidth Hybrid Current Sensor based on Enhanced Analog Operational Amplifier Circuit

“…The sensitivity of the Rogowski coil is defined by the mutual inductance M. The parasitic self-inductance L Rog and the parasitic capacitance C Rog of the Rogowski coil results in a pole, which can be damped with a burden resistance R b . The damped Rogowski coil is described by the following transfer function in the Laplace domain (22) (23) :…”

“…The second approach tries not only to reduce the decrease of the frequency response, it compensates the frequency dependent behavior of the Rogowski coil in order to achieve a constant frequency response. For a Rogowski coil this approach is presented in (23) . In this paper the resonance compensation is combined with the signal processing of a hybrid current sensor.…”

A Review of Megahertz Current Sensors for Megahertz Power Converters

“…This method can however only marginally increase the bandwidth of the RCCS. Another compensating technique for the coil should hence be considered, like that proposed in [138]. To illustrate that technique, relevant Bode diagrams have been plotted in Fig.…”

“…On the whole, the review here is based on the authors' indepth research on various RCCSs for power-electronic applications [102], [138], [166]- [167] and the many references read. It is therefore relatively comprehensive with many meaningful insights and trends shared with regard to current sensors for MHz power converters.…”

Design guideline for PCB integrated, high bandwidth, current slope sensing based on a planar Rogowski coil

“…This will require additional damping by decreasing 𝑅 d which leads to reduced bandwidth and output voltage. To increase the bandwidth an additional characteristic shaper proposed in [21] can be implemented.…”