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The series-stacked architecture provides a method to increase power delivery efficiency to multiple processors. With a series-stack, Differential Power Processing (DPP) is needed to ensure that processor voltages remain within design limits as the individual loads vary. This work demonstrates a switched-capacitor (SC) converter to balance a stack of four ARM® Cortex-A8 based embedded computers. We...
Multilevel Cascaded H-Bridge (CHB) converters have attractive features for the implementation of large scale photovoltaic systems. They can be directly connected to high voltages and the multilevel voltage synthesis reduces the harmonic distortion introduced. In addition, they have individual DC links ideal for connecting photovoltaic arrays. Existing high performance voltage balancing techniques...
We present a method for designing a stabilizing reference circulating current for modular multilevel converters. To this end, an optimization problem is formulated. This optimization problem takes into account conflicting control requirements such as reducing the oscillating component of the circulating current as well as the oscillating component of the arm voltages. Tracking of the obtained reference...
This paper describes a methodology for field evaluation of large PV system impacts on distribution systems based on data collected from several phasor measurement devices deployed on two distribution feeders. The method utilizes a series of performance indicators and pattern trending approaches to process large amounts of granular data gathered from fielded data acquisition instruments (1 second GPS...
This paper proposes a monolithic capacitor-current-controlled hysteretic buck converter with a transient-optimized feedback circuit (TOFC) and a transient-hold (TH) technique. The proposed TOFC simultaneously optimizes both load and dynamic voltage scaling (DVS) transient responses. In addition, the proposed TH technique significantly reduces the required compensation capacitance to save chip area...
This paper presents a high efficiency, net-zero charge neural stimulator. A new stimulation strategy is proposed to reduce the charge error that originates from the irreversible charge diffusion, which is a common issue in traditional current matching stimulator designs. In addition, an arbitrary channel configuration of the working and counter electrodes is achieved. Two methodologies are applied...
This paper presents a new control method for boost DC/DC converters combined with voltage source inverter systems to minimize the DC-link capacitor-current RMS value. The examined converter system consists of a multi-phase boost converter and a three-phase inverter with common DC-link capacitor. A general analytical expression for the DC-link capacitor-current RMS value is derived, which allows to...
This paper proposes a novel control scheme for minimizing the line loss of three-phase converters under unbalanced grid voltages. Most prior works focus on balancing phase currents or eliminating dc-link voltage ripples. However, they do not consider rms currents, so the efficiency may be lowered. In this paper, the optimal current reference is proposed to minimize sum of squares of rms currents in...
Two methods for the estimation of the DC voltages in the capacitors associated to the DC buses in a cascaded multilevel converter topology are analyzed. To reduce the number of voltage sensors, available information from inductor currents and line voltage sensors is used as input to a discrete time model of the converter. Additionally, information from the switching state of each converter's cell...
This paper presents a method for estimating the voltages at the individual sub-module capacitors of Modular Multilevel Converters (MMCs). The estimation method is designed according to a predictor-corrector scheme with a model-based prediction stage utilizing the arm current measurements and the internal modulation signals of the control system. The corrector stage is based on measurement of the total...
This paper presents a remotely powered sensing tag for biomedical applications. Energy is transfered by an EM-field to a dual frequency band antenna and fed to an analog front end. The AC voltage resulting on the antenna gets rectified, pumped to 3.3V and stored in an 2.2μF buffer capacitor. When the buffer capacitor is full a measurement with an integrated impedance measurement circuit can be processed...
This guide applies to the protection of shunt power capacitor banks and filter capacitor banks. Included are guidelines for reliable applications of protection methods intended for use in many shunt capacitor applications and designs. The guide does not include the protection of pole mounted capacitor banks on distribution circuits or capacitors connected to rotating machines.
A new type of Class-E rectifier which can regulate the output voltage or power is proposed. The proposed circuit consists of a conventional Class-E zero-voltage-switching (ZVS) rectifier and a common-grounded multi-step controlled-shunt capacitor (CSC). The proposed circuit can output a number of output voltages with changing the state of switches of the common-grounded multi-step CSC. The CSC is...
An emulated multi-path PID compensator for buck converter with a large step-down ratio for application to a LCD TV is presented. The emulated multi-path PID compensator is adopted in order to avoid output noise and achieve fast transient characteristics. Furthermore, the proposed buck converter with the large amplitude of its sawtooth waveform is robust to noise such as ground bouncing voltage. The...
This paper presents a new electrolytic capacitorless and single-stage controlled three-phase battery charger with electrical isolation to provide wide-range output voltage for EV applications. To achieve this, a three-phase rectifier cascaded by a current-feed isolated converter is proposed to yield DC voltage output and eliminate the bulk electrolytic capacitor installed behind the rectifier. Therefore,...
By injecting a small signal pseudo-random binary sequence (PRBS) based injection sequence, chosen for its wideband spectral content, into the inverter's PWM control signal and utilizing digital network analyzer techniques, an accurate estimation of the output impedance can be obtained without external equipment. This knowledge can then be leveraged to tune the inverter's digital deadbeat controllers...
At SCL, an automated system is developed to calibrate DC current sources and meters, including electrometers and femto-ammeters, from 100 pico-amperes (pA) down to 100 femto-amperes (fA). The system comprises an in-house developed control software, a ramping voltage generation circuitry and a precision air capacitor.
It is an effective approach to ensure the non-exceeding of the breaking capacity by adopting fault current limiter to restrain short-circuit current. Considering a persistent increase of the short-circuit current level in power grid, a kind of resonant fault current limiter is proposed. The appropriate parameters are selected for the electromagnetic transient simulation analysis on the resonant fault...
A theoretical analysis, control and a simulation of a grid connected photovoltaic system using an output LCL filter is detailed in this paper. In order to reduce the complexity of the system, a linear voltage and current controllers have been developed for a three phase grid connected inverter. Those controllers simultaneously regulate the dc link voltage (the photovoltaic power is delivered to the...
The quality of the supply voltage in automotive power nets is deteriorating because of the electrification of auxiliary components with high and dynamic power demands. This electrification, on the one hand, serves the reduction of CO2-emissions and, on the other hand, it is required in vehicles with an electric drive train. For the stabilization of the supply voltage active units can be used. In this...
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