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Transformerless photovoltaic systems are one of the best options to connect a photovoltaic system to the electrical grid given their high efficiency, low cost, small size and low weight regarding their counterparts based on a transformer. In this paper a multilevel single-phase inverter is aimed to link a photovoltaic generator with the electrical grid with reduced common mode current. A sinusoidal...
This work aims at estimating and comparing the power limits of ΔΣ and charge-redistribution successive-approximation register (CR-SAR) analog-to-digital converters (ADCs), in order to identify which topology is the most power-efficient for a target resolution. A power consumption model for mismatch-limited SAR ADCs and for discrete-time (DT) ΔΣ modulators is presented and validated against experimental...
A feasibility study of an 8-bit fast converter is presented. The advantages and limits of conventional SAR architectures are discussed and, on the basis of that, a possible optimal architecture is proposed. It uses a 4+4-bit scheme with combination of the DAC outputs in the current domain at the input of the latch. The circuit has been implemented with a 28 nm FDSOI CMOS technology. Post layout simulation...
The massive amount of data recorded by dense electrode arrays which are routinely connected to Nyquist-sampling signal conditioning blocks introduces new design challenges for implantable and wireless biological signal acquisition. Five different architectures of implantable multichannel neural recording systems are compared in terms of power and area constraints. Silicon results of a 16-channel spatial-domain...
This paper presents a novel inverter topology that is applied to single-phase grid-connected photovoltaic systems. The proposed topology has an active decoupling function, which not only eliminates the double line frequency ripple power in the dc-link but also accepts large voltage ripple across the decoupling capacitor in order to reduce the requirement of the decoupling capacitance. Traditionally,...
In October 2013, Diversified Technologies, Inc. (DTI) successfully installed and began operation of a 120 kV, 120 A, 1.7 ms Marx modulator for the High Energy Accelerator Research Organization in Japan (KEK).
The optimal design of SAR ADCs requires the accurate estimate of nonlinearity and parasitic effects in the feedback charge-redistribution DAC. Since the effects of both mismatch and stray capacitances depend on the specific array topology, complex calculations, custom modeling and heavy simulations in common circuit design environments are often required. This paper presents a novel MATLAB-based numerical...
The conventional binary weighted array SAR ADC is the common topology adopted to achieve high efficiency conversion, i.e. with less than 10 fJ/conversion-step, even requiring extra effort to design and simulate full custom sub-fF capacitors. This paper presents the design and the optimization of an asynchronous SAR ADC with attenuation capacitor achieving an efficiency similar to conventional binary...
This paper introduces a soft-switched high-frequency-link inverter for grid-tied PV systems. This single-stage inverter can perform the step-up/down operation and also has the ability to effectively harvest the highest possible power from the PV array. The high-frequency link is formed by an ac inductor and a small ac capacitor without the use of bulky short-life electrolytic capacitors. The link...
The optimal design of successive approximation register (SAR) analog-to-digital converters (ADCs) requires the accurate estimate of nonlinearity and parasitic capacitance effects in the feedback charge-redistribution digital-to-analog converters (DACs). Since the effects of both mismatch and stray capacitances depend on the specific array topology, complex calculations, custom modeling and heavy simulations...
This paper proposes a novel single-stage buck-boost three-Level NPC inverter for the grid-tied photovoltaic (PV) system, which can effectively solve the unbalanced operational conditions generally appeared between two coupled independent PV sources induced by the unequal irradiation and temperature distribution. The proposed control scheme can simultaneously guarantee the maximum power point (MPP)...
High-density wireless intracranial neural recording is a promising technology enabling the autonomous diagnosis and therapy of brain diseases. Increasing the number of recording channels is accompanied by the increased amount of data resulting in an unacceptable transmission power. A comprehensive study of possible compressed sensing methods in the context of neural signals has been done, and the...
The quasi-Z-source inverter (qZSI) which originated from the Z-source inverter (ZSI) topology provides an alternative for the conventional two stages DC-DC/DC-AC PV based inverter system with less component number, simpler topology and overcomes some of the limitations and problem associated with the conventional inverter topology. In the application of grid-connected PV inverter system, power storage...
This paper surveys the-state-of-the-art of high power photovoltaic (PV) inverters, and a novel quasi-Z source cascaded multilevel inverter (CMI) is proposed for application to MW-scale PV system. The proposed quasi-Z source CMI has a constant dc-link voltage and minimum KVA rating, compared to a traditional CMI with an unbalanced dc-link voltage and oversized KVA rating. Four MW-scale PV inverter...
This paper proposes the advanced performance control method of two-stage photovoltaic (PV) inverter with fast energy storage component coupled. The two-stage circuit employs transient maximum power point tracking (MPPT) method to realize fast MPP tracking without causing output distortion and dc-link variation. The generated energy pulse is then absorbed by fast energy storage component. Besides,...
This paper proposes a grid-connected Photovoltaic (PV) system based on a multilevel Current Source Inverter (CSI) topology. The topology proposed here consists of parallel-connected CSI modules operating at a very low switching frequency. For n number of inverter modules, 2n+1 current levels are resulted in the output. In the multilevel inverter topology, each inverter module has its own PV source,...
For the characteristics of low DC voltage output of PV array, a novel BOOST DC-AC inverter cirCuit is proposed, it is used DC chopper and based on the AC chopper principle. The tasks of boost and inverter are undertaken only by one level BOOST DC-AC cirCuits. With adjustable high voltage transfer ratio, PV inverter can be easily reaLized. By Matlab / SimuLink simulation and verified in the prototype,...
This paper presents an analog-to-digital converter using state-of-the-art techniques in 180nm process. Making use of charge sharing, asynchronous logic circuitry, scaled digital voltage supply and a novel sampling scheme, this ADC achieves a figure of merit (FOM) of 45fJ per conversion step in simulations. This FOM is close to reference designs reported in 90nm.
Analysis and experimental results for a new switching scheme and topology for charge sharing DACs used in successive approximation register (SAR) ADCs is presented. The characteristics of the SAR algorithm are exploited to develop a switching scheme that reduces the number of required unit capacitors by nearly an order of magnitude over conventional charge sharing DACs without the aid of any additional...
In some photovoltaic applications it is possible to remove the transformer of the system in order to reduce losses, cost and size. In transformerless systems the photovoltaic module parasitic capacitance can introduce leakage currents in which the amplitude depends on the converter topology, on the pulse-width-modulation and on the resonant circuit composed by the system components. In this paper...
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