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The grid inductance is a sensitive parameter to be considered in order not to degrade the control system performance and to guarantee the system stability. In this paper, the Grid Inductance estimation based on Generalized Integrators (GIGI) method is proposed. It carries out an online grid inductance detection, which disturbs the grid by injecting a time-limited and small-amplitude harmonic voltage...
One of the biggest challenges faced in the characterization of wide-band gap (WBG) semiconductors is the accurate measurement of the current through the device. Most measuring techniques available do not have the necessary bandwidth to capture the high-frequency current content in such systems. Many of the solutions that do have the necessary bandwidth introduce a “choke-point” into the system by...
The defect detection mechanism for eddy current nondestructive testing (ECNDT) is related to the interaction of induced eddy currents in the metal test specimen with flaws, and the coupling of these interaction effects with the test probe sensor.
Coupling factor is a important design parameter in inductive power transfer (IPT) systems as it determines the amount of VA effort required from the primary pad to deliver the necessary VA to the secondary pad. As IPT systems involve more complex magnetic systems such as multi-coil primary pads (whose currents can have an amplitude and phase difference), the effective coupling factor becomes more...
Diagnostics and prognosis for fracture healing still remains an unanswered problem leading to increased suffering and costs during treatment especially in cases of delayed and/or non-unions. Healing is a continuous process, therefore should be measured on a continuous quantitative scale. Bone is a biological semi-conductor that displays a combination of many electromagnetic properties generated due...
This paper presents a concept of a tunable inductance using coupled transmission lines. The proposed method suggests applying signal at one line of a shorted coupled transmission line and injecting current at the other line of the coupled pair. This way the inductance value can vary proportionally with the ratio of the currents in the coupled lines. A detailed analytical discussion is presented. A...
The circulating bearing current depends on the common mode stator ground current and the stator laminated core impedance, but also on the bearing impedances and on the rotor impedance of the circulating bearing current path. In the literature, the rotor impedance was neglected, or it was considered as a small air gap and end-winding cavity inductance. It is shown here by calculation and measurement...
Large pulsed power drivers often utilize multiple self-magnetically insulated transmission lines (MITL) in parallel to reduce inductance. The MITL currents must be recombined into a single anode-cathode gap, often through a post-hole convolute. Efficient post-hole convolute operation is necessary to maximize the current delivered to the load.
Trends in high performance computing (HPC) systems point to ever-decreasing power delivery network (PDN) impedances. While there is no particular theoretical minimum impedance, practical limitations present boundaries which will be difficult to exceed. In this paper, we explore specifically the practical limitations of the printed circuit board (PCB) portion of the PDN, concluding that useful implementations...
For the operation of electrical equipment the use of power electronic circuits is necessary. These circuits cause conducted interference emission, whereby the electromagnetic compatibility of electronic components is impaired. To prevent these problems the attenuation of various filter concepts based on simulation models and measurement techniques were investigated. This interference can be reduced...
Vacuum interrupters are the state of the art technology for breaking short-circuit currents and load currents in medium-voltage systems. Consequently, further applications may be established for vacuum switchgear technology. For each new application, the characteristics of vacuum interrupters have to be observed. One of these is current chopping that results in high overvoltages when switching off...
A study to characterize the impedance of the electrodes of a calculable cross capacitor by means of four-terminal measurement techniques has shown that the inductance is a function of frequency mainly caused by magnetic properties and skin effect. The four-terminal measurement technique used can eliminate the effects resulting from the lead impedances and contact resistances. Moreover, the disturbing...
This paper describes the development of Inductive Voltage Divider (IVD) with the ratio of 8∶1 by means of the combination of three binary IVDs. The self-calibration method of the ratio error and phase error of the binary IVD was reported. We also report the determination of the phase error of a 8∶1 IVD which has relative higher input impedance by comparing with the known phase error self-calibrated...
The experiments on x-ray backlighting of wire-array Z-pinch using X-pinches as x-ray sources were performed. A wire-array z-pinch was placed between the anode and the cathode. The anode plate was normally mounted on return-current rods, but here two of these rods were replaced by two X-pinches. In order to obtain two time-resolved images, we need to know the current division among the paralleled X-pinches...
High-frequency large current tests are critical in almost all switch-mode power conversion systems. To measure this large current, large size current sensor with large current rating is always needed to bring many disadvantages of bulk volume, less accuracy and high cost. One of the solutions is to use current split technique with the split wires of the winding in magnetic components to measure the...
A better knowledge of the grid impedance is essential in order to improve power quality and control of the Distributed Power Generation Systems (DPGS) and also for a safe connection or reconnection to the utility grid. An LCL-filter associated to a Voltage Source Inverter (VSI) is usually used in DPGS based on renewable energy. The VSI controller is used to determine the grid impedance in both healthy...
The TRV amplitude factors of 4kVA and 300kVA transformers under transformer limited fault conditions were measured. The measured factors were 1.4 and were lower than the IEC standard. The frequency response of the transformer impedance was investigated using a frequency response analysis (FRA). FRA measurement graphs showed that the short-circuit inductance value of test transformers gradually decreases...
The estimation of the line impedance can be used by the control of numerous grid-connected systems, such as active filters, islanding detection techniques, non-linear current controllers, detection of the on/off grid operation mode. Therefore, estimating the line impedance can add extra functions into the operation of the grid-connected power converters. This paper describes a quasi-passive method...
In this paper, we propose a novel toroidal current probe embedded in multi-layer printed circuit boards (PCBs) for electrostatic discharge (ESD) detection. The proposed current probe consists of an inner via-array, bridge lines, and an outer via-array, which surround an ESD current path and form a toroid to detect an ESD current. A transfer impedance between a port injected an ESD current and the...
A digital sampling system which can fast compare inductors with ac standard resistors in the frequency range between 20 Hz and 20 kHz is described. It can also precisely measure inductance at heavy current or high voltage. Inductors from 10mH to 10H in the low audio frequency range can be measured with the least relative uncertainty of 50 to 100 parts in 106.
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