Inductive Coupled In-Circuit Impedance Monitoring of Electrical System Using Two-Port <italic>ABCD</italic> Network Approach

Abstract

By treating the inductive coupling probes and the electrical system to be monitored as three cascaded two-port ABCD networks, the in-circuit impedance of the electrical system can be extracted with ease. The proposed method simplifies the setup calibration and allows real-time impedance monitoring of critical electrical system to be implemented without interrupting its normal operating conditions. In this paper, the theory behind the proposed ABCD networks approach is described. The proposed approach has overcome the poor measurement accuracy of the conventional inductive coupling calibration method above 30 MHz and has achieved good accuracy up to 100 MHz with a maximum measurement deviation of 3.6%. Finally, using a dc-powered motor as a practical example, the ability to detect the change of in-circuit impedance of the motor under different operating conditions is demonstrated.

Advances in Modeling and Suppression Methods of EMI in Power Electronic Converters of Third-Generation Semiconductor Devices

“…Li. et al [18] extracted the online impedance of an electrical system by treating their inductively coupled probe and the monitored electrical system as three cascaded two-port networks. Their method simplified the setting and calibration process, and could monitor the real-time impedance of the key electrical system in the study without interrupting the normal operation of the system, providing convenience for EMI research.…”

Two-Probe Setup with Improved Calibration for Online Impedance Measurement of Electrical Assets

“…The initial findings on the inductive coupling method was published in [17]. The project was further built on and optimized to streamline the online impedance measurement procedure based on the cascaded two-port network theory [18,19].…”

“…The response signal is then being detected by channel 1 of the SGAS via the receiving probe. The online impedance of the DUT is labelled as ZDUT, whereas ZS and ZW denotes the impedance of the source voltage and circuitry wiring excluding the clamped sections of the wire, respectively [18]. The points where the wire are being clamped by the two inductive probes are denoted as p1 and p2 in Figure 6.…”

“…Taking into consideration the significance of the online impedance of electrical assets, the extraction of online impedance is now a notable process, thus, a few methods to extract the online impedance will be comprehensively examined with its integrity and limitations highlighted. The extraction methods can be categorized into three types, that is the voltage-current measurement method [8][9][10][11][12][13], capacitive coupling method [14][15][16] and lastly, the inductive coupling method [17][18][19][20][21][22].…”

Multi-Channel Time-Domain EMI Evaluation of Dominant Mode Interference for Optimized Filter Design in Three-Phase Systems

“…Thus, knowing the noise source and the load impedances, we can design a perfect filter for each particular case. Various approaches for in-situ impedance measurements were devel-oped previously [5], [9]- [12]. However, all of the proposed approaches are time-consuming, due to the pre-measurement calibration process and require expensive equipment which is not always available.…”