purpose: to evaluate the role of active uveitis on refractive errors changes. methods: a cohort single group study was conducted on patients with acute or recurrent uveitis. cyclorefraction was performed in both phases of active and quiescent. sphere, cylinder and sphere equivalent power were compared in active and quiescent phases and analyzed statistically. results: sixty-six patients (eighty...

The transmission of electricity from the source to load is mainly carried out using a three-phase line [...]

This paper demonstrates an enhancement of power quality in grid integrated systems with the help of the proposed control strategy for voltage source converter based active power filters. The Shunt Active Power filters (SAPF) are extensively utilized in modern grid integrated systems to diminish the power quality concerns associated with it. The SAPF is one of the various power filters, which ha...

this paper presents a grid connected photovoltaic system, which acts as both power generator and active power filter (apf), based on flying capacitor multicell (fcm) converter. increase in the number of output voltage levels, natural self-balancing of flying capacitors and dc link voltage and lower power rating of components are the main futures of fcm converter compared with conventional multi...

Active filters have proven to be more effective than passive techniques to improve power quality and to solve harmonic and power factor problems due to nonlinear loads. This paper proposes a control scheme based on the instantaneous active and reactive power. The inverter of this active filter is a three-phase, two-level converter. Space vector technique is used as modulators and pattern genera...

In regions with high penetration of Distributed Energy Resources (DER), grid congestion is mostly caused by power feed-in generators. this context, conventional approaches for solving the problems are Active Power Curtailment (APC) DER and reinforcement. wake increased generation, it not only interest how to obtain reinforcement, but also consider APC during planning. The challenge such plannin...

This paper presents a novel control approach used in shunt active power filter based on variable structure control combined with Random PWM technique (RVSC) that provides robust, fast, and more favorable performance for active power filter. This control strategy is compared with two other strategies to show the effectiveness of the introduced methods; pulse width modulated proportional-integral...

reactive power management plays an essential role in the secure operation of the power system as an ancillary service. although in electricity markets, the particular attention is paid to active power, the reactive power also plays an important on total generation costs of electricity. on the other hand, as it is mainly confined to local consumption, to avoid market power and maintain the secur...

When low output voltage and EN61000-3-2 compliance are put together, not too many options can be used, especially if the power range is between 300–600 W. This paper presents one of the best solutions to comply with both specifications at the same time: the use of a single-stage topology to comply with the low-frequency harmonic limits combined with a half-bridge converter with complementary co...