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The paper presents a new four-level voltage source converter (VSC). Compared to conventional four-level converters, this proposed converter has fewer components and can be used for a higher power density system in low and medium voltage applications. Its principles and advantages are studied in this paper. The effect of various redundant switching states on the voltages of flying capacitors is analyzed...
Droop control is a widely used technique for load sharing in DC microgrids (MGs). However, it has its limitations due to the MG voltage deviating from its rated level and, more importantly, it suffers from possible poor current sharing accuracy. Voltage drops across coupling line impedances is the main factor that causes these limitations, which is further deteriorated by the virtual impedance introduced...
Uninterruptible Power Supplies (UPS) have several closed loop control topologies for control of Voltage Source Inverter (VSI). The topologies vary mainly due to choice of control/feedback variable. This paper attempts to categorize different control topologies and highlights the similarities/differences between them. Further, an analytical study on the basis of steady-state and transient performance,...
One of the major drawbacks of Finite Control Set — Model Predictive Control (FCS — MPC), is the high switching frequency, besides a spread harmonic spectrum. Despite of this, the FCS — MPC provides excellent speed to changes of references and disturbances. In this work we present a control strategy based on FCS — MPC that allows a reduction of the switching frequency in steady state, increasing the...
Dual active bridge (DAB) with input-series output-parallel (ISOP) structure is capable to interconnect low voltage DC micro grid with medium/high voltage DC distribution grid, named as DC solid state transformer (DCSST). This paper presents a combined decoupling control strategy for the DCSST, which aims to achieve input voltage sharing among sub-modules and enhance voltage control of the parallel...
We propose a Least Squares Estimation procedure for estimating the admittance matrix of multi-bus DC MicroGrids (MGs). In the proposed solution, the generators simultaneously inject training signals in the form of small deterministic perturbations of the primary droop control parameters and measure the related steady state deviations of the bus voltage. When the training signals meet sufficient excitation...
The multi-actuation-based model predictive control (MPC) method can significantly improve the steady-state performance of cascaded H-bridge (CHB) inverters. However, a large computational burden is generated on digital controller when this method is applied for CHB inverter due to its large number of control actuations. In this paper, a new MPC method is proposed for a single-phase CHB inverter. In...
Different types of multi-input DC-DC converters have been proposed by number of researchers for the purpose of integrating more than one energy source. Development of a suitable power electronic interface is most essential for integrating these sources with very less number of components. Nowadays, it is very much essential to stabilize the output voltage of DC/DC converters in order to ensure maximum...
Advanced CMOS devices below 28nm allow supply voltages lower than 1V. For applications with higher input voltage in such devices, stacked MOSFET structures with a three-level technology are commonly employed. The stacked structure can also reduce the output voltage ripple substantially. Figure 10.5.1 shows a three-level single-inductor triple-output (SITO) converter and also compares the transient...
This paper presents a SPV (Solar Photovoltaic)-DSTATCOM (Distribution Static Compensator) grid tied system controlled using a unity zone variable forgetting factor RLS (Recursive Least Square) algorithm along with P & O (Perturb and Observe) maximum power point tracking method. The proposed SPV grid tied system operates in two modes: Mode-1, the SPV-DSTATCOM mode which comes into operation during...
The Supercapacitor Assisted Low Dropout Regulator (SCALDO) is a novel approach to achieving high end-to-end efficiency (ETEE) in linear, step-down, DC-DC converters. This is a patented technique and it has been well established with various proof-of-concept prototypes showing its efficiency advantage in the range of a factor of 1.33 to 3 along with the other excellent linear characteristics such as...
Power optimizers are dc-dc converters, featuring maximum power point (MPP) tracking operation, deployed on a per module basis in modern PV plants, adding value on flexibility, diagnostic capability and energy yield. This paper considers the non-inverting buck-boost converter used as a power optimizer, with emphasis on the control scheme applied to it. In the analysed configuration, the converter inductor...
This paper presents a hyperbolic tangent function (HTF) based higher order adaptive control algorithm with a perturb & observe (P&O) MPPT (Maximum Power Point Tracking) for a three phase grid connected single stage SPV (Solar Photovoltaic) system with DSTATCOM (Distribution Static Synchronous Compensator) capabilities. The variable learning based HTF reduces the mean square error in the system,...
Digital low dropout voltage regulators provide digital process synthesiz ability, fast transient response and performance adaptation but lack steady state voltage regulation performance. To overcome this lack of steady state accuracy due to limit cycle oscillations, a hybrid low dropout voltage regulator topology designed in 130 nm CMOS process is presented. In the proposed topology, the operational...
This paper presents a stacked-topology resonant switched-capacitor (ResSC) dc-dc converter to achieve a high voltage conversion ratio. The topology can be generalized to any N-to-1 dc-dc conversion application with only a single inductor. Multiphase interleaving can be further employed to improve the ripple cancellation and reduce requirement for bypass capacitors. To enable a wide output range while...
Applications such as under-sea power prefer dc current distribution in a series cable connection instead of dc voltage distribution due to the long distance and cable loss. Power converter modules employed in these scenarios have a constant current input. In this paper, steady state analysis and unique design considerations are presented for the series resonant converter topology with constant current...
This paper is concern with the modelling and simulation of three phase front end converter for power quality improvement. The space vector modulation technique is used to control the three phase front end converter. The objective of this work is to get unity power factor at the input side, dc link voltage regulation against load variation and reduction of harmonics in input side line current. The...
This paper deals with a single stage solar photovoltaic (SPV) array tied with a three phase grid by using an improved second order generalized integrator quadrature signal generator (ISOGI-QSG) based control algorithm to improve power quality of the grid. The maximum point power tracking (MPPT) is achieved by using an incremental conductance method. The incremental conductance MPPT method is effective...
This paper presents important characteristics on the study of universal filters topologies. The integration of series and shunt active power filter was proposed by [1], where the two converter shared the same dc-link bus voltage. By a steady state analysis it was noted that there is a significant difference between two voltage converters. The voltage capability of shunt convert is bigger than series...
This paper proposes a novel dc-dc buck converter that presents a static gain from 0.5 to 1, maintains the typical linear characteristics of the buck converter and reduces the voltage stress on the power components. The proposed converter is composed by a switched capacitor cell that was introduced in the conventional buck converter, which results in a hybrid buck converter. A theoretical steady state...
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