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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...
This paper presents a study of the transmitted power and efficiency of a wireless power transfer system which employs a metamaterial consisting of an array of multiple magnetically coupled resonant inductors. In order to reach the maximum efficiency when the receiving inductor is located at the end of the metamaterial line, the system can be designed and matched simply through the magnetoinductive...
In order to have full control of voltage controlled, power devices gate voltages must be under control. This requires low impedance (RG and LG) in gate drive circuits. A prototype of a gate drive circuits applied to an IGBT half-bridge module, results in LG of 2.5nH and gate resistance RG of 0.54 Ohm for a 400A/1200V IGBT module. Test results demonstrate the controllability of the gate voltage during...
This paper presents an analytical and experimental study of a passive impedance matching interface based on a large inductive reactance but with a centimeter-scaled size for practically enhanced piezoelectric energy harvester performance at low frequency. Low frequency vibration normally leads to a large capacitive reactance value for small-sized piezoelectric energy harvesters and it is impractical...
Conditioning of network impedance by insertion of a virtual inductance as an inherent feature of the converter control system has the potential to extend the range of stable operation of the overall system. This paper presents a scenario in which such potential is explored and its range of application is identified. It shows first that implementation of a virtual inductance is naturally suited for...
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...
With the emergence of new power semiconductor devices, the switching speeds are increasing. The stray inductance of switching cells must be minimised to limit the over-voltage of power switches like IGBTs, MOSFETs or HEMTs. This is one of the reasons why 3D integration concepts are considered today. This paper deals with a busbar-like integration concept called “Power Chip-on-Chip” (PCoC). Although...
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...
Electrical Impedance Tomography is applied to acquire the impedance characteristic, which is correlative with the physiological and pathological status of a body, and reconstruct the images of impedance distribution. Current injection with voltage measurement phantom is widely adopted in the application of biomedical detection. Voltage controlled current source (VCCS) develops an important part and...
A vector triangle method for the measurement of the parameters of inductors, capacitors and resistors is described. The method can measure the values of the impedance, quality factor (Q factor) or dissipation factor (D factor) and is independent of the phase measurements, as it only involves the effective values of three voltages. The unknown impedance is connected in series with a known standard...
Three virtual inductance implementation methods are reviewed. Based on the features of the novel concept distributed FACTS, the Direct Reactance Synthesis method is chosen and analyzed in detail, especially for the negative inductance case. The impedance characteristics of virtual negative inductance is shown and discussed. The power flow controllability is verified by simulation.
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...
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.
Based on Wide Area Measurement System (WAMS), a new method for live line measuring the impedance parameters of transmission lines with mutual inductance is proposed. The mathematical model of the new method is explained in detail. The new method uses no extern voltage source and it only uses the zero-sequence interference voltages among the transmission lines as the measurement sources. The hardware...
Inductive power transfer (IPT) technology is gaining popularity as an efficient wireless power transfer mechanism in numerous applications, ranging from microwatt bio-engineering implants to high power battery charging systems. A typical IPT system employs two separate controllers on both powering and receiving sides of the system to facilitate contactless power transfer in an efficient and controllable...
The control of a PWM inverter is affected by variable inductance present in the power line of the grid. This paper presents a new implementation of grid-tied inverter with weighted-average-current feedback control (WAC) and an embedded online technique to determine the grid line impedance. By adding an inter-harmonic voltage periodically in the modulation of the PWM and measuring the current response,...
Fast Id-Vg measurements on very high performance devices (very low channel ON-resistance) and larger area devices (therefore large gate capacitance) are subject to serious distortions. Methods to minimize these distortions are introduced in this paper; thus expanding the applicable range of this important measurement technique.
Power Quality has become a determining factor in product performance and reliability. The reactive portions of the power distribution network (PDN) have a greater effect on power quality than DC IR drop. Resonance in the parallel inductance and capacitance network creates an impedance peak in the frequency domain and undesirable voltage noise in the time domain. The on-chip voltage noise is usually...
Linear Induction Motors (LIMs) have asymmetrical parameters. It causes LIMs thrust pulsation. Some methods have been proposed to avoid the thrust pulsation such as DTC (Direct Thrust Control) with PI control. These methods need parameter information. This paper proposes a method to identify the asymmetrical parameters by DC Decay Testing Method on alpha-beta axis. This method identifies the parameters...
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