A single-phase grid-connected converter is usually adopted in low-power renewable systems. This paper deals with a novel five-level converter topology that follows this development.. The proposed converter architecture is based on a full-bridge topology with two additional power switches and two diodes connected to the midpoint of the dc link. Since the two added levels are attained by the discharge of the two capacitors of the dc link, the midpoint voltage is balanced and obtained with a specific pulse width modulation (PWM) strategy. This solution is designed for renewable energy systems, where unity power factor operations are generally required. Never the less, a variation of the proposed topology which allows four-quadrant operations.

ABSTRACT-Now-a-days the new family of dc-dc converters based on three state switching cell and voltage multiplier cells. It present a demonstrate of some advantages and limitations of a several topologies were typically use in voltage step-up applications. The operating principle of this family has chosen the boost converter and discussed in detail. The analysis of converter can applicable in uninterruptible power supplies, fuel cell systems and it is adequate in operating the high-gain boost stage with cascaded inverters in the renewable energy systems. Furthermore, It is applicable in dc voltage step-up is demanded, like electrical fork-lift, audio amplifiers, and some other applications. KEYWORDS:dc-dc converters, voltage gain, voltage number cells (VMCs), Boost converters I.INTRODUCTIONDepending on the appliance nature, many kinds of static power converters are necessary for the adequate conversion and acquisition of the energy provided by primary sources like electrical phenomenon arrays, wind turbines, and fuel cells. Besides, considering that the price of renewable energy systems is high, the utilization of high-efficiency power electronic converters may be a should.The need for solid-state ac-dc converters to enhance power quality in terms of power factor correction, minimized over all harmonic distortion at input ac mains, and exactly regulated dc output has intended the investigation of many topologies supported classical converters like buck, boost, and buck-boost converters. Boost converters operative in continuous-conduction mode became particularly fashionable because reduced magnetic attraction interference levels result from their utilization.. The approach additionally employs the principle of interleaved converters, because it is extended to a generic range of legs per winding of the autotransformers and high power levels.A three-state switching cell (3SSC) can be obtained by the association of two two-state switching cells (2SSCs) interconnected to a center-tapped autotransformer, from which a family of dc-dc converters can be derived. This concept was first introduced in, as the so-called cell type B is obtained. The first topology for PFC applications based on the 3SSC was introduced. It can be obtained by replacing the input source of the dc-dc boost converter presented in by a typical single-phase diode bridge and an ac voltage source. The presence of the diode bridge causes conduction losses to increase because the current always flows through four semiconductor elements. Attempts to achieve high output voltage gain using the 3SSC and the dc-dc boost converter were performed. Although only two diodes and two capacitors are added to the original topology, the extension to PFC applications with high efficiency is limited by the presence of increased number of components in the current path during each operating mode. This mode is also called boundary conduction mode because it represents the intermediate operation between CCM and discontinuousconduction mode (DCM). The analysis of the criti...

No abstract