The conventional Boost converters cannot provide such a highdc voltage gain, even for an extreme duty cycle. As a result, the conversion efficiency is degraded and the electromagnetic interference (EMI) problem is severe under this situation . In order to increase the conversion efficiency and voltage gain, many modified boost converter topologies have been investigated in the past decade -.
ABSTRACT: This paper consists of the development of highefficiencydc to dc boost converter. The boost converter is used to improve the efficiency of the solar panel. The low voltage input of source is boosted into high voltage output. We can achieve the power efficiency of about 90% to 95%. The input current ranges from 4.5% to 52%. Some practical application has been done to verify the result obtained.
ABSTRACTDue to increase in population, there is an increase in demand for consumption of electricity; renewables sources like Solar Photovoltaics [PV] and fuel cell stack are becoming popular. Solar PV and fuel stack are preferred as it operated at low voltages. Due to which, there is a need for a high voltage, a high-efficiencyDC-DCconverter for renewable applications requiring highDC link output voltage. The main objective of the project is to achieve a regulated output voltage at the DC link and also protect output filter from the fluctuation caused by the change in the output load. In a high voltage gain, DC-DCconverter the output filter needs to be protected to avoid the filter potential to reach more than the rated voltage level of 380VDC in case of load fluctuation. It is necessary to protect the output smoothening filter from overcharging in order to avoid filter damage and eventual circuit breakdown. In this project in order to regulate and protect the same, a voltage feedback control technique used along with the help of microcontroller PIC16876P a circuit is designed which will sense the output voltage level, take corrective action and provide PWM signals to operate the power MOSFET which will, in turn, avoid filter damage.
Being a semiconductor device, the PV system is static, quite, and free of moving parts, and these make it have little operation and maintenance costs. Even though the PV system is posed to its high capital fabrication cost and low conversion efficiency, the skyrocketing oil prices make solar energy naturally viable energy supply with potentially long-term benefits. The output characteristics of PV module depends on the solar insolation, the cell temperature and output voltage of PV module. The mathematical PV models used in computer simulation have been built for over the past four decades. Almost all well-developed PV models describe the output characteristics mainly affected by the solar insolation, cell temperature, and load voltage. However, the equivalent circuit models are implemented on simulation platforms of power electronics. Recently, a number of powerful component -based electronics simulation software Package has become popular in the design and development of power electronics applications. The simplest equivalent circuit of a PV cell is a current in parallel with a diode. The output of the current source is directly proportional to the light falling on the cell. During darkness, the PV cell is not an active works as a diode, i.e., a p -n junction .It produce neither a current nor a voltage. However, if it is connected to an external supply it generates current, called diode current or dark current.
Efficiency is the most critical and important parameter for any power supply. A lot of work has been published in the field of improving efficiency. Since the efficiency of buck converter drops both at light load and at heavy load as shown in fig 2, the research is divided into two directions depending on different applications. Applications such as battery-powered portable devices need to be designed for highefficiency over entire load ranges extended from light load to heavy load, and especially at the light load range, since they operate at this region most of the time. This paper is targeting at these applications and working on improving light-load efficiency.
step-up DC-DCconverter for LED backlighting applications. An unregulated multi-modes charge pump is used as the post-stage of boost converter and performs a rough voltage conversion. The charge pump is located at the low current side therefore can have very highefficiency. It can switch between 1x, 2x and 3x conversion modes according to the number of LEDs in series. With the charge pump, the maximum output voltage of Boost converter is greatly reduced, therefore a low cost device can be used in Boost converter and extremely duty cycle is avoided. Although the two stages are cascaded, it is proved in this paper that the overall efficiency can be improved, especially at high gain. Without a transformer, the proposed charge-pump based step-up converter not only achieves high gain, but also improves the efficiency. Compared with bulky transformers, the added charge pump can be integrated with a Boost regulator (except flying capacitors) for single chip solution and saves space.
Abstract: - This paper presents a new high-efficiency-high-step-up based converter integrating two stype DC- DC Boost and Flyback coupled magnetic converter with recovery stage dedicated to smart HVDC distributed architecture in renewable energy production systems. Appropriate duty cycle ratio assumes that the recovery stage work with parallel charge and discharge to achieve high step-up voltage gain. Besides, the voltage stress on the main switch is reduced with a passive clamp circuit and thus, low on-state resistance Rdson of the main switch can be adopted to reduce conduction losses. The circuit is simple to control. As a final point of this research, the simulation and the prototype investigational results are presented to demonstrate the effectiveness of this proposed converter.
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 high step-up highefficiencydc-dcconverter for photovoltaic energy conversion is designed. The proposed converter employs a coupled inductor and two voltage multiplier cells to achieve high step-up voltage gain. The operating principle and the steady-state analyses of voltage gain are described in detail. Then a C filter and PI filter is used to reduced the harmonics and these are results are compared. Obtaining output voltage 400 V for 30 V input via MATLAB simulation. The maximum efficiency of the prototype is nearly 97.7% and the efficiency is higher than 97% over a wide load range.
DC to DC converters are important in portable elec- tronic devices such as cellular phones and laptop com- puters, which are supplied with power from batteries primarily. Such electronic devices often contain sever- al sub-circuits, each with its own voltage level require- ment different than that supplied by the battery or an external supply (sometimes higher or lower than the supply voltage, and possibly even negative voltage). Additionally, the battery voltage declines as its stored power is drained. Switched DC to 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 to DC converters also regulate the output voltage. Some exceptions include high-efficiency LED power sources, which are a kind of DC to DC convert- er that regulates the current through the LEDs, and simple charge pumps which double or triple the input voltage.
Power Generation by Non-renewable resources result in Pollution around the world. The Depletion of these resources prove to be a Major Concern for Future Generation. Thus the Need for Alternative Power Sources are Essential. Out of the available Renewable sources, solar Power Generation has a better Potential and Most Reliable among the others and they are also the Fast Developing Alternative Power Source in the Present Time. MPPT Controller helps in Improving and Utilizing the available Source in the Maximum Possible way. The conventional Boost Converters for High Voltage Step Gain have Higher Ripple Current and Voltage which are responsible for Losses. Further they are affected by the pulsating input current due to the switched operation of capacitors or inductors. For minimizing these Losses and also to improve the Overall Efficiency, the Interleaved Operation is suggested. This Converter setup makes use of the Multiplier circuits to improve the Output Voltage. The Coupled Transformer will reduce the Cost. The Leakage Inductance will be fed back to the Transformer. The Converter and the Coupled Inductors are present along with the Voltage Multiplier circuit are used for the operation. The Converter decreases the Inrush Current in the Inductor which improves the Performance and thereby reducing the Stress.
The design of interleaved converter from conventional converter is done. The existing conventional converter even though having a similar output voltage has higher ripple values and also at higher duty cycle the converter struggles, and also their efficiency gets reduced due to higher stress for a longer time of operation. While the interleaved boost converter has a higher efficiency with lower losses and ripples values and the converter does not struggle like the conventional step up boost converters. Hence they are very much reliable than the conventional boost converters used for harvesting the solar power.
Although the buck–boost configuration is cheaper than the Cuk one , some disadvantages, such as discontinuous input current, high peak currents in power components, and poor transient response, make it less efficient. On the other hand, the Cuk converter has low switching losses and the highest efficiency among nonisolated DC–DC converters. It can also provide a better output-current characteristic due to the inductor on the output stage. Thus, the Cuk configuration is a proper converter to be employed in designing the MPPT.
There is a rapid development of renewable energy system calls for a new generation of high gain DC/DC converters with highefficiency and low cost.A MVDC converter is required which is able to boost the voltage from 1-6 to 15- 60KV to link the output of generator to the MVDC line.Many high gain enhancement techniques were investigated in previous to achieve high voltage conversion ratio with high efficiency.Switched capacitor structure,tapped/coupled inductor based technique,,transformer based technique, voltage multiplier structure or combinations of them are thetechniques.But each technology has its unique advantages and limitations.In past many gain extension methods ofboost converter by adding only diodes and capacitors were investigated.The method of combing boost converter with traditional Dickson multiplier and Cockcroft-Walton multiplier to generate new topologies were proposed in.An elementary circuit employing the Super lift technique was proposed in.The concept of multilevel boost converters was investigated in .From the above topologies, a new boosting converter with a single switch and single inductor is proposed by employing bipolar voltage multiplier. The second order HBC is shown in Fig.2.which decreases the voltage rating of output filter capacity and exhibits the nature interleaving operation characteristics.A smaller ripple with single switch and single inductor has achieved in this topology on maintaining high voltage gain.Manymore structures are achieving high gain recently were also reported  but they adopted atleast two inductors or switches,or some are based on tapped inductor which may complicate the circuit design and increase cost.
The model indicates that the coupled inductance will lead to an increase in the gain and the decrease in ripples. Finally, this paper analyzes and describes step by step the process of designing, and simulation of highefficiency low ripple voltage buck boost DC-DCconverter for the photovoltaic solar conversion system
various topologies of converter and inverter schemes have been proposed in literature. A review of non-isolated high- step-up dc/dc converters is presented in  for a grid-connected inverter, including the analysis of multilevel converters , , cascaded boost converters , switched capacitor converters , , boost converters integrated with a coupled inductor to achieve high-step-up conversion , , combination of coupled inductor, and switched capacitor. Device parasitic and diode reverse recovery are the main issues and constraints for these converters, which limit the efficiency and voltage gain. Compared with voltage- fed converters, current-fed converters are demonstrated and verified for lower input voltage with wide variation. However, the major limitations of such converters are hard switching and snubber requirement to absorb the voltage spike to limit the device voltage. But snubber leads to low efficiency. A flyback snubber was introduced to recycle the absorbed energy with increased circuit and control complexity.
Development of digital core chips poses serious challenges to the power supply design. High performance switching DC-DCconverter must meet requirements of high current, low voltage tolerance, fast transient response, high power efficiency, small profile and low cost. The conventional PWM control with constant switching frequency has limitation to improve both transient response and power efficiency because there is a conflicting requirement on switching frequency. The control scheme with variable frequency has promising features to achieve better overall performance, but the issues in the reported design approaches limit their usefulness in the practical applications. This dissertation presents novel control architecture with variable switching frequency and novel implementation of the integrated controller. The control concept and the proposed circuits are verified by the prototype chip designed for mobile VRM applications. The contributions of this work are summarized as followings:
As shown in fig.1 step-up dc-dcconverter is always necessary for providing regulated high- voltage output to the post stage dc-ac inverter in high-power grid tied application. for the PEM fuel- cell system applications, the dc-dcconverter must be concerned with following design criteria: large step-up ratio low-input current ripple, and isolation. Typically input choke with high inductance is needed at low voltage side because high ripple current may cause undesired hysteresis energy losses inside the fuel cell stacks. Increased power loss and component size on the input choke are significant to result in poor conversion efficiency and low power density for step-up dc-dc converters in high power PEM fuel cell system.
Power converters have required improvement in the power efficiency as well as reduction of size and weight especially in mobile information/communication devices, traction converters, power control units for electric/hybrid vehicle, etc. Passive components and cooling devices usually occupy a much larger space than semiconductor devices in power electronics building block. It is well known that when many DGs are connected to utility grids, they can cause problems such as voltage rise and protection problem in the utility grid. To solve these problems, new concepts of electric power systems are proposed . Resonant converters eliminate most of the switching losses encountered in Pulse Width Modulation converters. The ac- tive device is switched with either Zero Current Switching or Zero Voltage Switching at its terminals. When current through the switch is made zero, it is turned on /off, it is known as zero current switching and when voltage across the switch is made zero, it is turned on / off, it is known as zero voltage switching . The main objective of this paper is to develop a modular high-efficiencyhigh step-up boost converter with a forward energy-delivering circuit integrated voltage-doubler as an interface for high power applications. In the proposed topology, the inherent energy self-resetting capability of auxiliary transformer can be achieved without any resetting winding. Moreover, advantages of the proposed converter module such as low switcher voltage stress, lower duty ratio, and higher voltage transfer ratio features are obtained .
Abstract—A new converter using a switched-inductor cell integrated with a switched-capacitor cell within a boost-like structure is proposed. The converter can achieve a very highdc conversion ratio. It can serve as the front-end dc-dcconverter for a fuel cell in a UPS system. The inductors and capacitors are switched in a parallel-series configuration. The charging circuit of the inductors from the source is separated from the load. A dc analysis of the new circuit leading to the formula of the dc gain and a breakdown calculation of the losses are given. The proposed Switched Capacitor Inductor (SCI) converter circuit can meet the highefficiency requirement and simple structure. A small resonant inductor is used in these converters to limit the current peak caused by switched capacitor. Therefore, the SCI converters have good performance and highefficiency as well the voltage stress of the converter is reduced. In order to verify the proposed Switched Capacitor Inductor (SCI) dc-dcconverter, modeling and simulation was carried out by using MATLAB.