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Maximum power point tracking (MPPT) is required to extract the maximum available power in PV systems. Wide variety of methods exist in literature, with range of complexity and effectiveness. The features of these diverse methods are usually evaluated at specific environmental conditions for a tiny period, and then the evaluations are generalized for PV systems working under long-term environmental...
The paper presents an original concept for interfacing of tensoresistive and capacitive force sensors with applications in modern microelectronics systems. In the first part, the authors show the results and conclusions of a PSPICE simulation for an original patented circuit. The used simulations models were introduced in some circuit components corresponding to the realistic behavior implementation...
in this paper, an integral sliding mode control method is proposed for maximum power point tracking MPPT voltage oriented loop. The aim is to obtain a better performance when applying it to stand alone. The proposed technique is studied and simulated by using Matlab/Simulink and simpower system packages. The obtained simulation results display significant enhancements by applying the proposed method...
Wayside energy storage systems (ESSs) in DC-electrified railway are recently studied as one of methods to save regenerative brake energy. Voltage basis control method to regulate the filter capacitor (FC) voltage in order to increase the assisting and absorbing power was developed. The voltage controller gain in this method should be set high for more energy-saving effect. However, it causes sometimes...
To date, a family of series-connected boost converter (SCBC) with enhanced efficiency has been presented as the front-end dc/dc stage of distributed photovoltaic (PV) inverter, which suffers the severe PV voltage/power oscillation when operated under unbalanced grid voltage condition. This paper proposes an operational scheme to enhance the performance of one type SCBC, namely the dual-input central...
Different from the former stable low-frequency oscillation cases, the one of Xuzhou North Railway Hub which occurred in January 2014 is particularly extraordinary because it caused abnormal voltage fluctuations. By testing the locomotive and traction power supply system, we obtained the voltage and current data which were in low-frequency oscillation. Then, to further analyze the mechanism of this...
High-speed train is supplied by alternating current (AC) power and bases on single-phase four quadrant (4Q) converter as one necessary part of the ‘AC-DC-AC’ transform process. The discrete mathematical model for a single-phase 4Q converter is derived with small disturbance method and digital control delay effect is considered in 4Q converter modeling and analysis. Focusing on stability characteristics...
The main objective of this project is to design of control circuit with the zero sequence components but the proposed system will enhance the power control ability in the adverse condition. The power converter is implemented with the new control technique. In the current component zero sequence components is controlled to reduce the unbalanced nature of ac source. This power converter have the ability...
Photo Voltaic (PV) power generation presents a high potential solution to the emerging energy needs and the pollution levels crisis around the world. PV cells have associated current-voltage nonlinear characteristics which vary according to irradiance levels, load impedance and temperature mainly. Maximum Power Point Tracking (MPPT) algorithms are relevant elements in economically viable PV systems...
This paper presents a novel Maximum Power Point Tracking(MPPT) method with digital control, together with an original Perturb and Observe (P&O) algorithm with variable step size. The step size calculation is independent of the slope of the power-voltage (P-V) characteristic of the solar panel. Simulation and experimental results are provided to show the efficiency of the system.
In grid-connected Photovoltaic (PV) applications, DC-links based on large electrolytic capacitors are used to attenuate voltage oscillations caused by the sinusoidal power injection into the grid, where the electrolytic capacitors introduce reliability problems. This paper proposes the unified modeling of the complete PV system in typical grid-connected operation conditions to design control strategies...
A current-balancing loop is often used in a voltage-mode multiphase interleaved voltage regulator (VR). It serves not only to balance the phase current but also to suppress the beat-frequency phase current oscillation in driving high-frequency dynamic loads such as recent central processing units (CPUs). In this paper, models were developed to predict the control characteristics of both the functions...
This paper presents the study of power system configuration effecting on switching overvoltage and insulation strength of high voltage equipment. Various sceneries such as energizing line with and without electrical load, energizing the overhead line with variable length, system with and without power cable and effect of source impedance are considered. The Alternative Transients Program (ATP) with...
The operation principle and the stability of V2C controlled boost converter operating in continuous conduction mode (CCM) is analyzed in this paper. It is found that V2C control is essentially a kind of control technique utilizing peak capacitor voltage and inductor current, quite similar to peak current control. Its corresponding control waveform and the sub-harmonic oscillation are investigated...
Power factor correction (PFC) AC-DC converters are well known nonlinear power electronics systems to exhibit instabilities in the form of period doubling and sub-harmonics oscillations at the line period. This undesirable behavior increases the total harmonic distortion (THD) and therefore can deteriorate enormously the system functioning by decreasing the power factor (PF). In this communication,...
This paper concentrates on the dynamic behavior of pulse-width-modulator (PWM) and the time-delay introduced in the modulation process is highlighted. In order to describe this effect, we derive a time-delay model, based on which the closed-loop stability of current-mode control is studied and a novel interpretation of the subharmonic oscillation is presented. Compared to its existing counterpart,...
The Z-source converter (ZSC) is an alternative power conversion topology that can both buck and boost the input voltage with improved reliability. Dynamic modeling of the ZSC from different perspectives has been studied. Based on these models, the dc-link voltage is controlled using direct measurement or measurement of the capacitor voltage. In this paper, two methods of dc-link voltage control of...
Polymorphic gates can be considered as a new reconfigurable technology capable of integrating logic functions with sensing in a single compact structure. Polymorphic gates whose logic function can be controlled by the level of the power supply voltage (Vdd) represent a special class of polymorphic gates. A new polymorphic NAND/NOR gate controlled by Vdd is presented. This gate was fabricated and utilized...
This paper presents a study of two maximum power point tracking methods for grid connected photovoltaic systems. The best operation conditions of the perturbation and observation and the incremental conductance are investigated in order to identify the performances of photovoltaic systems. Improvements of these methods can be obtained with the best adjustment of the sampling rate and the perturbation...
In this paper, feedback control design of Zero-Voltage-Switched Quasi-Resonant dc-dc converters is presented. The power stage model is derived by a method of circuit averaging, while the control stage model, consisting of an Error Amplifier (EA) and Voltage Control Oscillator (VCO), determined by the input/output relationship of the circuits. The obtained models are used in feedback control design...
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