in order to reduce the volume and size of distribution power transformer, precise and extended controlling of transformer output, the conventional transformers are replaced by intelligent universal transformers (iuts). in this paper, an iut, typical of iran national grid, with the voltage ratio of 20kv:380 v is designed and simulated. regarding the iut implementation, a cascaded h-bridge invert...

this paper presents a control strategy for fuel cell/energy storage power generation system during voltage sag conditions. the hybrid dc power sources are connected to grid using power electronic converters include dc-dc converter and grid connected voltage source inverter. the power from hybrid power sources is controlled during voltage sag by designing of control strategy for dc-dc converter....

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 this paper, a novel approach for control of the dc-dc buck converter in high-power and low-voltage applications is proposed. designed method is developed according to state feedback linearization based controller , which is able to stabilize output voltage in a wide range of operation. it is clear that in high-power applications, parasitic elements of the converter may become comparable with...

This paper proposes a stand-alone photovoltaic (PV) system based on a DC-DC positive output super lift Luo (POSLL) converter. A conventional sliding mode control, a sliding mode controller using a simple sign function and a linear controller using proportional integrator (PI) are used for the control of the PV panel voltage and POSLL converter inductor current and these methods are compared tog...

this paper presents a novel control method to improve the efficiency of low-voltage dc-dc converters at light loads. pulse width modulation (pwm) converters have poor efficiencies at light loads, while pulse frequency modulation (pfm) control is more efficient for the same cases. switching losses constitute a major portion of the total power loss at light loads. to decrease the switching losses...

In this paper, a new transformerless buck-boost converter based on ZETA converter is introduced. The proposed converter has the ZETA converter advantages such as, buck-boost capability and input to output DC insulation. The suggested converter voltage gain is higher than the classic ZETA converter. In the presented converter, only one main switch is utilized. The proposed converter offers low v...