In order to protect the natural environment on the earth, the development of clean energy without pollution has the major representative role in the last decade. By accompanying the permission of Kyoto Protocol, clean energies, such as fuel cell (FC), photovoltaic (PV), wind energy, etc., have been rapidly promote. Batteries or super capacitors are usually taken as storage mechanisms for smoothing output power, start-up transition, and various load conditions .The corresponding installed capacity of clean energies can be further reduced to save the cost of system purchasing and power supply. Solar energy is abundantly available that has made it possible to harvest it and utilize it properly.
and multiplier circuits are presented in this paper. Interleaving is done to minimize the size of the filter components. In this converter, better gain with improved efficiency is obtained without the high duty cycle of the switches used. The Converter is able to boost the Voltage to a Desired Level without Transformer. Further with this interleaved design the peak to peak current variation and losses which are due to switch operation is minimized. The interleaved boost converter has been designed with 12 V as input and 100V as the output. The primary windings of the inductor are used for minimizing the ripple current, while the secondary windings are set in series to maximize the voltage gain.
Multilevel topologies and modulation techniques have been developed and applied in high power system (Park et al., 2003). With the requirement of quality and efficiency in high power systems with the limitation of high power device switching speed, low total harmonic distortion (THD) and low switching frequency are desirable. Multilevel conversion structures represent a solution to improve the performances given by the classical structures with two voltage levels. Multilevel structures offer a reduction of the voltage stress that compensates the increased number of devices. Also these structures offer the advantage of reducing the size of the output filter by reducing the total harmonic content. An important structure is the Active Neutral Point Clamped Converter (ANPC) developed in 2001. It presents the advantage of an increased number of degrees of freedom. Also it allows the combination with other concepts in order to create structures with higher number of voltage levels and output parameters. Another class of multilevel converters introduces the coupled inductor concept (Selvaraj and Rahim, 2009). This type of converters offers an increased number of voltage levels, lower current stress in the semiconductor devices and better output voltage properties. The most commonly used topologies are neutral-point-clamped (NPC). In neutral-point-clamped inverter the dc-Link is split into number of smaller voltage levels using a bank of series connected bulk capacitors. The inverter structure allows the connections of the inverter poles to any of these voltage levels, thus generating a multi-level voltage waveform at the output. Several schemes have been proposed to solve these problems. In most DFIG-based WECSs, the load or grid is directly connected to the stator of the DFIG, and the rotor injection is controlled using an ac-dc- ac converter. Instead of two back-to-back converters, a diode rectifier followed by an inverter can also be used. For systems
The total power delivered is increased by transferring the inductive and capacitive energy simultaneously and thereby the losses in the circuit are also decreased. The two transformer modes, where the transformer operates under normal conditions and where it operates as a coupled-inductor, are combined together and therefore the magnetic core can be used more effectively and smaller magnetics can be used. Smaller current ripple than the previous high boost ratio converter topologies is achieved by the continuous input current of the converter. Since the current ripple is low, the input capacitance can be reduced and it is easier to implement a more accurate MPPT for PV modules. The conduction losses in the transformer are greatly reduced because of the reduced input current RMS value through the primary side. The voltage stress of the active switch is independent of the input voltages. The turn- off current of the active switch is reduced due to the introduction of the resonant portion of the current. The decreased RMS current value and smaller turn-off current of the active switch helps to enhance highefficiency at light output power level and low-input voltage operation. The voltage stresses of the diodes are kept under the output dc bus voltage.
For storage or other DC components to be used in conjunction with AC loads, some type of power conversion capability is required. Considering that the output characteristic of a photovoltaic cell has a wide voltage range, depending on the operating conditions of a photovoltaic cell, the DC/DCconverter needs to have a wide input voltage range to regulate the constant output voltage. To achieve high step-up and highefficiencyDC/DC converters is the major consideration in the renewable power applications due to the low voltage of PV arrays and fuel cells. The purpose of dc-dcconverter is insure the impedance adaptation between the PV source generation and the main utility by tracking the reference voltage required by the grid. The DC-DCconverter converts a DC input voltage, to a DC output voltage, with a magnitude lower or higher than the input voltage. 
The dc/ac operation of the RSC is used for delivering power from PV to grid, battery to grid, PV and battery to grid, and grid to battery. The RSC performs the MPPT algorithm to deliver maximum power from the PV to the grid. Like the usual PV inverter control, the RSC control is implemented in the synchronous reference frame. The synchronous reference frame proportional integral current monitor is employed. In a reference frame rotating synchronously with the fundamental excitation, the fundamental excitation signals are transformed into dc signals. As a result, the current regulator forming the inner most loop of the monitor system is able to regulate ac currents over a wide frequency range with high bandwidth and zero steady state error. For the pulse width modulation (PWM) scheme, the usual space vector PWM scheme is used. Figure 7 presents the overall monitor block diagram of the RSC in the dc/ac operation.
Abstract—The distributed generation (DG) systems based on the renewable energy sources have rapidly developed in recent years. These DG systems are powered by micro sources such as fuel cells, photovoltaic (PV) systems, and batteries. PV distributed system in which the solar source is low dc input voltage. PV sources can also connect in series to obtain sufficient dc voltage for generating actuality voltage; however, it is difficult to realize a series connection of the PV source without incurring a shadow effect. High step-up dc–dc converters are generally used as the frontend converters to step from low voltage (12–40 V) up to high voltage (380–400 V). High step-up dc–dc converters are required to have a large conversion ratio, highefficiency and small volume. A novel high step-up dc–dcconverter for a distributed generation system is proposed in this paper. Through a voltage multiplier module, an asymmetrical interleaved high step-up converter obtains high step-up gain without operating at an extreme duty ratio. The voltage multiplier module is composed of a conventional boost converter and coupled inductors. Finally, the prototype circuit witha 40-V input voltage, 400-V output, and 1000- W output power is operated to verify its performance. The highest efficiency is 96.8%. In base paper author discussed only about the High Step up converter, in extension to this work we can use PV source
mW. As dissipation of ADP1111ANZ-5 is less than dissipation of the Boost DC/DCconverter, than dissipation of ADP1111ANZ-5 is always less than 500 mW. It is possible to make realization of Boost DC/DCconverter with higher output current which can decrease time of charging. This realized Boost DC/DCconverter has switcher and external switching transistor by which high output current is possible. The disadvantage of this Boost DC/DCconverter is low grade of efficiency because high output current causes high dissipation on the external switching transistor. Because this device is battery supplied it is more important to make Boost DC/DCconverter of highefficiency and the speed of battery charging is less important. On the output of Boost DC/DC converters protection from over voltage is realized by serial connection of schottky diode 1N5819 and zener diode of 5.1 V. It is used only in the case of malfunction of Boost DC/DCconverter to protect mobile phone. Voltage from the output of Boost DC/DCconverter is connected to female USB connector type A (figure 12). Pin D+ and D- from the USB connector are connected by resistor which resistance is 180 Ω. The yellow LED diode marks that Boost DC/DCconverter works. Switch is resided between NiMH batteries and the input of Boost DC/DCconverter. In that way unneeded consumption of NiMH batteries is prevented when Boost DC/DCconverter is not used.
Power plant located area, non-availability of geothermal sources , higher cost of generated electricity , higher cost of pumping and distribution makes the geothermal energy lee reliable compared to other sources. The main disadvantage of wind energy is that it is location specific. Also erection of wind power plant is costlier. All these factors necessitate the usage of solar energy as potential power source in the non-conventional power system. A typical solar system employs PV panels , each comprising a number of solar cells , which generate electrical power. PV installations can be either ground-mounted, mounted on the roof top or wall mounted. The mount may be fixed, or use a MPPT ( maximum power point tracker ) to follow the sun across the sky.
For the purpose of optimizing the output power from the solarPV array, the MPP tracking techniques are mostly utilized. An INC method of MPP tracking is used in this work for its capability of highly accurate tracking even under rapidly changing insolation conditions. The MPP tracking method adjusts the duty ratio of dc-dc boost converter in small step size. Smaller step size gives good MPP tracking.
In this paper a new high step-up DC-DCconverter suitable for photovoltaic application is presented. Due to the single-switch structure, an easy control and efficient MPPT is expected for the proposed converter. Moreover, because a neutral point at the output of the proposed converter is provided and connected to the negative terminal of the PV module, the amount of the ground leakage currents in photovoltaic systems is drastically reduced. High step-up DC- DC conversion in the proposed converter provides the possibility to amplifying the low produced voltage by PV module to reach the high peak voltage required for the inverter stage. Due to the soft switching of the diodes and the switch, a highefficiency is measured for the proposed converter under various output powers is connected to grid .In the grid voltage is maintained effective voltage at grid.
Thermal power plants (e.g. oil, diesel oil, coal or gas) produce two thirds of the world's electricity . However, they emit pollutants, responsible for climate deterioration and depletion of natural resources. Thus, the deployment of renewable energy remains an alternative to the phasing out of fossil fuels. In this context, photovoltaic industry has gained widespread popularity in the past decade, for its efficiency and low cost of manufacturing solar panels. In general, the photovoltaic generator (PVG) consists of several solar panels which are connected to the DC-bus through a DC-DCconverter (see Figure-1).
DC-DC Convertor is an electronic circuit which converts a source of direct current (DC) from one voltage level to another. DC to DC converters are important in portable electronic devices such as cellular phones, laptops computers, which are the supplied with power from batteries primarily. Such electronic devices often contain the several sub-circuits, each with its own voltage level requirement different from that supplied by the battery or an external supply (sometimes higher or lower than the supply voltage). Additionally, the battery voltage declines as its stored power is drained. Switched DC-DC converters offer a method to increase voltage from a partially lowered battery voltage thereby saving space instead of using multiple batteries to accomplish the same thing. Most DC-DC converters also regulate the output voltage. Some exceptions include high-efficiency LED power sources. In that paper the DC-DCConverter supply electricity to the battery with is connected to the relay as well as Auxiliary supply. As shown in the fig.
Arun K. Verma et al.  has investigated the solar power generation isolated portable system using a boost converter and a single stage sine wave boost inverter. The proposed configuration boosts the low voltage of photovoltaic (PV) array using a dc-dc boost converter to charge the battery at 96V and to convert this battery voltage into high quality 230V rms ac voltage at 50Hz for feeding autonomous loads without any intermediate conversion stage and a filter. A maximum power point tracking (MPPT) scheme was proposed with series connection of a dc–dcconverter input with a PV panel for highefficiency.
conditioning system (PCS) must have high conversion efficiency and low cost. Generally, a PV PCS uses either a single string converter or a multilevel module integrated converter (MIC). Each of these approaches has both advantages and disadvantages. For a high conversion efficiency and low cost PV module, a series connection of a module integrated DC–DCconverter output with a photovoltaic panel was proposed. The output voltage of the PV panel was connected to the output capacitor of the fly- back converter. Thus, the converter output voltage was added to the output voltage of the PV panel. The isolated DC–DCconverter generates only the difference voltage between the PV panel voltage and the required total output voltage. This method reduces the power level of the DC–DCconverter and enhances energy conversion efficiency compared with a conventional DC–DCconverter.
These factors can negatively affect the PV cell conversion efficiency. PV energy system has some advantage such as pollution free, abundant availability, less maintenance. In solar photovoltaic system the optimum efficiency (which is 7-16%) second inverter efficiency (90-97%) and the efficiency of MPPT algorithm (over 98%). In photovoltaic system integrated to grid, the grid inverter is three inverter in this paper it is an important component which invert dc power which is obtain from P-V system array alternating power to synchronized voltage and frequency of connected utility grid. In this paper the major component are photovoltaic plant, consist of P-V array, MPPT unit, three level inverter, step-up converter and utility grid.
changes in the environment. PI-controlled system is less responsive to real and relatively fast alterations in state and so the system will be slower to reach the set point. Recently intelligent based schemes have been introduced [7-10]. Among the intelligent based methods fuzzy logic has its own merits such that the algorithm is easy to form. The shape of the membership function of the fuzzy logic controllers can be adjusted such that the gap between theoperation point and maximum power point can be optimized. A SEPIC dc-dcconverter provides constant dc voltage which has a duty cycle that is controlled by the FLC MPPT controller [8-11]. Among all the available converters, SEPIC has the merits of non- inverting polarity, easy to drive the switch with low input current pulsating for high precise MPPT that makes its characteristics suitable for the low power PV based charger system. SEPIC converter can raise the output voltage to the suitable range, the supply an isolation route to isolate the input and the output terminals after terminating the charging. But this circuit has two disadvantages; one is low efficiency and the other is it needs two inductors .
Solar energy provides much cheap, clean and abundantly available source of generating electric power. The only hindrance is its high installation cost and low conversion efficiency. Therefore, to increase the efficiency and power output of the system, it is necessary to couple PV array with the boost converter of high voltage gain (Leyva et al., 2013). The conventional DC-DC converters are normally used for the voltage step-up. But for high voltage gain the duty cycle nearly approaches unity, which may have high impact on conduction loss, switching loss and thus results in low efficiency. To counteract the above mentioned problem, a switched-capacitor DC-DCconverter is proposed in this paper. The switched capacitor converter can obtain a high voltage gain. The configuration consists of many capacitors connected in parallel during the charging phase and in series during the discharging phase which results in high voltage gain (Chen et al., 2013). In the literature, a novel method to integrate the boost converter with switched capacitor is proposed which provides an excellent output voltage regulation (Gang Wu et al., 2014). *Corresponding author: Dr. Seyezhai, R.,
The output power generated from the PV panel is varying under certain environmental conditions such as temperature, irradiation, shading etc, hence PV system has low conversion efficiency [9,10]. Therefore a good MPPT is required to ensure the maximum available power from the solar panel. The output power of the PV module is directly proportion to the solar irradiation and inversely proportional to the ambient temperature. For better PV utilization it must be operated at equilibrium point. This point is commonly known as Maximum Power Point (MPP) or peak power voltage. MPPT technique can be used in both standalone and grid connected PV system. The general block diagram of MPPT technique is as shown in Fig.4. normally it consists of a PV array, DC-DCconverter for boosts the output voltage generated from PV array and a MPPT controller .
In typical solar MPPT system, switching DC-Dc convertor is the mandatory element for tuning the PV output power towards its maximum peak level, by changing the duty cycle D. Buck converters and the boost converters are the most popular circuits, among the DC-DC converters, and both are mostly used in solar Maximum Power Point Tracking system because they are less expensive and more simple compared to the buck- boost and CUK converter. Boost converter is more favorable than Buck converter for MPPT application, because most of the solarPV module output voltage would be lower than the required external load voltage. Moreover, the switching component in Buck converter is placed at the Input side and series with input voltage, which will discontinue the current flow within the system. This will definitely result in energy losses during the power generation process. Hence Boost converter provides greater benefit in terms of cost saving and higher efficiency. [8-12]