Contactless AC/DC Wide-Bandwidth Current Sensor Based on Composite Measurement Principle

Abstract

With the accelerated construction of the smart grid, new energy sources such as photovoltaic and wind power are connected to the grid. In addition to power frequency, the current signal of power grid also includes several DC signals, as well as medium-high and high-frequency transient signals. Traditional current sensors for power grids are bulky, have a narrow measurement range, and cannot measure both AC and DC at the same time. Therefore, this paper designs a non-intrusive, AC-DC wide-bandwidth current sensor based on the composite measurement principle. The proposed composite current detection scheme combines two different isolation detection technologies, namely tunneling reluctance and the Rogowski coil. These two current sensing techniques are complementary (tunneling magnetoresistive sensors have good low-frequency characteristics and Rogowski coils have good high-frequency characteristics, allowing for a wide detection bandwidth). Through theoretical and simulation analysis, the feasibility of the composite measurement scheme was verified. The prototype of composite current sensor was developed. The DC and AC transmission characteristics of the sensor prototype were measured, and the sensitivity and linearity were 11.96 mV/A, 1.14%, respectively. Finally, the sweep current method and pulse current method experiments prove that the designed composite current sensor can realize the current measurement from DC to 17 MHz.

Magnetoelectric Sensor Operating in d15 Thickness-Shear Mode for High-Frequency Current Detection

“…From the LOD test result in Figure 7b, it can be seen that the proposed ME current sensor has a current sensitivity of about 11.4 mV/A and is able to detect weak current down to 3.82 µA, which can be comparable to the commercial TMR current sensor. The performance of the proposed high-frequency As reported, the typical dynamic frequency ranges for most TMR current sensors were from DC to several hundred kHz or several MHz [30][31][32]. Then, the current test waveforms of TMR and ME current sensors at different high frequencies above 1 MHz were compared, and the results are shown in Figure 8.…”

“…As reported, the typical dynamic frequency ranges for most TMR current sensors were from DC to several hundred kHz or several MHz [ 30 , 31 , 32 ]. Then, the current test waveforms of TMR and ME current sensors at different high frequencies above 1 MHz were compared, and the results are shown in Figure 8 .…”