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This paper presents a mathematical analysis of how energy return in grid-connected single-phase photovoltaic systems affects the sizing of passive components. Energy return affects the size of the link capacitor, making it larger than reported in the literature. One of the main points of this article is that an inverter connected to the grid using a DC–DC converter with an appropriate link capacitor is analyzed. The energy return is caused by the value (in Henry units) of the L-filter, which is also analyzed in this paper. The analysis shows that there is a link between the value of the L-filter and the voltage of the DC bus. The analysis assumes two conditions: (1) the DC bus voltage is always higher than the peak value of the grid sinusoidal voltage, and (2) there is a unity power factor at the connection point between the grid and the L-filter. To operate in an open loop, a compensation phase angle is calculated and introduced in the single-phase inverter modulation; this phase angle compensates the phase shift caused by the L-filter, avoiding the use of a phase-locked-loop (PLL) control system. The L-filter ripple current is evaluated by Fourier analysis, and the DC bus ripple voltage is evaluated by considering the energy returned to the link capacitor. The results of the analyses are compared with existing methods reported in the literature. The results also show that, to minimize the value of the L-filter, the DC voltage must be almost equal to the maximum voltage of the grid. Equations to assess the value of the DC-link capacitor and the L-filter in function of their ripples are developed. The results were verified with simulations in Simulink and experimentally. [ABSTRACT FROM AUTHOR]

This study compares ripple port, stacked switched capacitor, and capacitive energy storage architectures for active power decoupling, comparing the number of components, performance, energy density, DC-link capacitor reduction, efficiency, and frequency operation to highlight their main benefits and drawbacks for single-phase grid-connected applications. The overview reveals equivalent effective energy density without electrolytic capacitors, as well as enhanced simplicity, performance, and durability, thereby providing stacked switched capacitors as an attractive power-decoupling alternative for multi-stage connected applications, based on the principle that its individual buffer capacitors absorb and deliver energy without tightly constraining their individual terminal voltages, while maintaining a narrow range voltage at the buffer DC port. [ABSTRACT FROM AUTHOR]

There is currently a growing interest in replacing the internal combustion engine with electric motors in transportation applications. However, there are different problems related to electric motors for this application. One of them is the oversizing of the energy decoupling system since to ensure that the decoupling capacitor can store the power fluctuations, the capacitance required by the system is usually oversized. This leads to preference for the use of capacitors with construction technologies that have a lower lifetime than the remaining elements of the propulsion system, directly affecting the reliability of the system. In this article, the energy flow handled by the decoupling capacitor is analyzed considering the critical case of operation of an induction motor to minimize the capacitance required by the propulsion system; emphasizing the conditions that generate a higher energy return, from the motor mode of the electric machine to the decoupling capacitor. From the energy analysis, an equation for the capacitor calculation is obtained, involving proportionality factors that relate to the different operating powers, reducing up to 62.2% of the capacitance value required by the decoupling system, under conditions of maximum energy return in motor mode, compared to existing equations in the literature. [ABSTRACT FROM AUTHOR]

The main contribution of this study is to show the effect of light-emitting diode (LED) modelling in the design of offline drives. The authors propose the use of a source voltage and resistance model (SVRM), consisting of a threshold voltage source in series with the characteristic resistance, for the modelling of the LED. The offline drive used for the analysis is the flyback converter operating in discontinuous conduction mode. The equivalent circuit is analysed by superposition and the AC circuit is analysed with phasors. The analysis has proven that the flyback converter can be modelled as a current source feeding the output capacitor in parallel with the load. Likewise, the analysis demonstrated that the current ripple is always greater than the voltage ripple when an LED is used as a load. In order to validate the theoretical analysis, a design methodology for the flyback converter with the SVRM as a load was developed. The designed circuit was simulated in Spice and implemented in a prototype. Experimental results using an LED as load are compared with the same circuit using a simple resistance as load. The experimental results confirm the theoretical analysis with an error of <6.6%. [ABSTRACT FROM AUTHOR]

This paper proposed the use of a ringer, a self-switched inductive storage system, for applications involving reluctance accelerators, a kind of electromagnetic launcher, and compatible with applications where portability is a requirement. There will be shown three different useful approximations for the analysis of the ringer, employed as a power source for a reluctance accelerator. First, it described the equations governing the que behavior of an ideal unloaded ringer, and then the equations for the ringer with an uncoupled inductive load, and ultimately a Lagrangian model for the ringer as an inductive power source for a reluctance accelerator, capable to make predictions about the currents through the circuits and the exit speed of the projectile for a given firing. The accuracy of the predictions made with the third approximation, the Lagrangian model, was tested experimentally. [ABSTRACT FROM AUTHOR]

Summary: In this paper, the analysis, design, and implementation of a power supply based on a multi‐stage‐shunt class E amplifier applied to ozone generation are presented. The proposed topology operates with pulsating waveforms and allows unidirectional energy flow from the power supply to the load with no energy return. Furthermore, due to the multi‐stage operation, it presents a lower stress in the switches compared with other similar topologies. To validate the proposed topology, a prototype was designed to feed a set of ozone generating cells in a power range of 0 to 500 W. This prototype provides an efficiency of 95% with an ozone production of 10.5 g/h and efficacy of 22.89 g/kWh. The proposed power supply is an alternative to feed any other type of dielectric barrier discharge load while keeping the efficiency of the power supply above 90%. The analysis, design, and implementation of a power supply based on a multi‐stage‐shunt class E amplifier applied to ozone generation are presented; due to the multi‐stage operation, it presents a lower stress in the switches compared with other similar topologies and higher efficiency. To validate the proposed topology, a prototype was designed to feed a set of ozone generating cells in a power range of 0 to 500 W. [ABSTRACT FROM AUTHOR]