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We present a second generation current conveyor (CCII) based electronic interface for differential capacitive sensors. The sensor interface performs a capacitance-to-voltage conversion and has been designed in a discrete board as well as in an integrated version showing a linear input/output characteristic. Simulated and experimental results conducted on the discrete element board employing the low...
Flying capacitor multilevel (FCML) converters are known to naturally balance the capacitor voltages through the use of phase-shifted pulse-width modulation. However, in practice, the capacitor voltages can still deviate and active balancing is often required. This work investigates the origins of the voltage imbalance in practical implementations of such converters and presents corresponding solutions...
Researches to control water content of Polymer Electrolyte Membrane(PEM) are actively performed for increasing performance & durability of Fuel cell. This Research to control water content focused on measurement of PEM impedance. In this paper, The measurement system of PEM Impedance based on AC impedance method is proposed. Bi-directional DC/DC converter is designed to measurement of PEM impedance...
A floating capacitor H-Bridge converter is proposed to stabilize the automotive energy net against undesired voltage spikes and to limit the voltage range for the electrical loads. In comparison to classical converter topologies the proposed floating H-Bridge converter with integrated energy storage device provides lower switch-voltage stress and allows therefore the implementation of high-current...
A novel quadratic boost A-source impedance network is proposed to realize converters that demand very high voltage gain. To satisfy the requirement, the network uses an autotransformer where the obtained gain is quadratically dependent on the duty ratio and is unmatched by any existing impedance source networks and normal dc-dc converters with coupled magnetics at the same duty ratio and turns ratio...
The complexity of electrical energy nets in modern cars is increasing rapidly due to the rising number of dc-dc converters and motor controllers. Multi-converter systems may lead to negative impedance instability that must be avoided in the automotive energy net under all circumstances, including faulty conditions such as a failure of batteries or other energy storage devices. Many stability criteria...
The CLIC study is exploring the scheme for an electron-positron collider with high luminosity and a nominal centre-of-mass energy of 3 TeV. The CLIC pre-damping rings and damping rings will produce, through synchrotron radiation, ultra-low emittance beam with high bunch charge, necessary for the luminosity performance of the collider. To limit the beam emittance blow-up due to oscillations, the pulse...
In this work, we present two analog current-mode interfaces performing differential sensor capacitance measurements through a voltage reading. The AC peak-to-peak output voltage is proportional to the measurand x that is directly related to the differential capacitance variation. The first interface is able to read the sensor change through a current-to-voltage conversion, while the second one employs...
This paper presents results of impedance measurements of low-voltage (230 VAC) electrical grid at the wall socket. The measurements were performed in context of Power-Line Communication (PLC) in urban and suburban areas. There have been measured complex impedance (magnitude and phase) in 10 kHz – 1 MHz frequency range, covering CENELEC, ARIB and FCC bands. The measurements were performed using low-cost...
This research proposes a bridgeless rectification circuit for impedance matching and voltage boosting of a Wi-Fi energy harvesting system. The impedance matching is achieved by an LCL T-network in parallel with an inductive branch, and such an arrangement can boost the voltage by combined effect of T-network and bipolarity charging of the output capacitor. The return loss equation and an estimated...
This paper presents the concept of a three phase AC power source with virtual output impedance, which is mainly used for the development, validation and testing of grid connected components. The main advantage of the proposed system is the adjustability of the output voltage, frequency, harmonics and also the grid impedance. Based on the requirements and the related standards a LC-output filter is...
This contribution presents results from an investigation into conducted emissions of an automotive inverter in a component level EMC test setup with unshielded cables. The primary goal of the investigation is to develop a profound understanding of the shape of the disturbance voltage's frequency spectrum at the line impedance stabilization network. Complying with that objective, common-mode currents...
In this article, we present a circuit solution for sensing and controlling functional electrical stimulation (FES) currents. The objective is to keep both charge balance and residual electrode voltage under a safe limit throughout stimulation. In the proposed circuit, the stimulation current is set through an ultra-low-power charge-redistribution digital-to-analog converter (CR-DAC). Each stimulation...
All types of passive components present variations for most of their electric parameters as a function of several operating conditions (temperature, frequency, voltage). Capacitors, unlike other types of passive components (resistors and coils), are more sensitive to these variations. This paper presents the effects of temperature and bias voltage on power electronic capacitors for frequencies ranging...
Adjustable speed drives (ASDs) with regenerative PWM rectifiers — both voltage source rectifiers (VSR) and current source rectifiers (CSR) — have LC filters on their input to attenuate the high frequency components of current and achieve reduced levels of total harmonic distortion (THD). The capacitors used in these filters are predominantly of the metallized film construction and are prone to catastrophic...
Passive components, in particular capacitors, are widely used in power electronics, especially in EMC filters. Their impedance variation with respect to operating conditions (frequency, temperature, operating voltage) is very significant and shouldn't be neglected. In this paper, we aim to characterize the influence of bias voltage variations on capacitor parameters (C and ESR) over a wide frequency...
This paper describes a digital alternating current (ac) quadrature bridge for impedance measurements under development at INMETRO. This bridge is primarily intended to allow the comparison of ac resistors with standard capacitors but it could be applied to a myriad of impedance-measurement tasks as the precise determination of dissipation factor of capacitors, of resistor time-constants, as well as...
This paper covers some aspects of voltage dependence of solid dielectric capacitors and resistors to be used for metrology purposes. The investigations are motivated by the need of a quantitative rather than qualitative information on components' voltage dependency when one faces challenges on precision low noise analog electronic circuit design. Current measurement methods under development to determine...
The growing number of electronic devices inside vehicles has motivated research and development activities in Vehicular Power Line Communication (VPLC) systems. Advantages of the VPLC approach include reduced complexity and cost of the wiring harness. Among the design challenges of VPLC systems is the problem of impedance matching. The access impedance at the modem port is a time varying quantity...
An architecture of a programmable gain integrating amplifier is presented. The circuit operates using two clock phases for sampling and amplification and the gain is defined by the ratio between the pulse-width of a control signal and the integrator time constant, which is defined by a resistor and capacitor. The proposed architecture also has configuration switches that enable its use in the modes...
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