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A novel non-isolated DC-DC converter is proposed by combining quadratic boost converter with voltage multiplier cell. The proposed converter has low semiconductor device voltage stress and switch utilization factor is high. The superiority of the converter is voltage stress of the semiconductor devices depends on voltage multiplier (VM) cell. By increasing the VM cell the stresses across the devices reduce drastically. The proposed converter has same number of components compared to certain voltage lift converters taken for comparison. A detailed comparative study is made on the proposed converter with few voltage lift converters in the literature, conventional boost with VM cell and quadratic boost converter. A 40 W prototype is constructed with 12 V input voltage and 96 V output voltage to verify the performance and validate the theoretical analysis of the proposed converter. Keywords: High gain, Quadratic, Multiplier, Voltage stress, Efficiency

The power generated from TEG is relatively unstable owing to temperature variations at its hot and cold side terminals. The dc-dc converters can provide more stable power output thereby improving the overall efficiency of TEG system. However, to facilitate better performance improvement, maximum power point tracking (MPPT) algorithm can be applied to extract maximum power from TEG system. Therefore, parameter analysis of a TEG/dc-dc converter system in different modes is being carried out. A TEG-dc-dc boost converter model is analysed in both MPPT and direct pulse width modulation (PWM) modes subjected to a variable load. To further study the capability of dc-dc converters to stabilise the TEG power output, increasing ramp and random hot side temperature is applied to the MPPT and direct PWM based modes so that the effect on output parameters i.e. voltage and power, can be analysed. It is noted that even for the random temperature input to the TEG, the output voltage resulting from the converter is almost constant. Therefore dc-dc converters are able to stabilise the power generated from TEG. It is also observed that dc-dc converter with MPPT based model is able to effectively extract the maximum power without having to adjust any component from the MPPT algorithm as it is the case with direct PWM based model. From the study, it has been established that proper selection of converter components is necessary to reduce converter losses as well interferences on the load connected to TEG-dc-dc converter system.

In recent years, the use of electrolyzers to produce cleanly and efficiently hydrogen from renewable energy sources (i.e. wind turbines, photovoltaic) has taken advantage of a growing interest from researchers and industrial. Similarly to fuel cells, DC/DC converters are needed to interface the DC bus with the electrolyzer. Usually, electrolyzers require a low DC voltage to produce hydrogen from water. For this reason, a DC/DC buck converter is generally used for this purpose. However, other DC/DC converter topologies can be used depending on the feature of the electrolyzer and electrical grid as well. The main purpose of this paper is to present the current state-of-the-art of DC/DC converter topologies which can be combined with electrolyzers. The different DC/DC converter topologies are compared in terms of output current ripple reduction, conversion ratio, energy efficiency, and power switch fault-tolerance. Besides, remarks on the state-of-the-art and remaining key issues regarding DC/DC converters are provided. © 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

This chapter describes boost–buck converters. These can either boost or buck the supply voltage, so the load voltage can be higher or lower than the supply voltage. These circuits are often used with battery-powered equipment and have the advantage of continuing to supply a constant current as the battery voltage falls below the LED load voltage. Both Cuk and single-ended primary inductor converter topologies are described.

[EN] A multilevel modular DC DC power conversion topology based on cascaded H-Bridge converters in a double II configuration is presented. The topology is intended to interconnect large power DC networks. A two level control hierarchy is used to regulate the DC voltage of each H-bridge module. At the top level, DC and circulating AC currents are used to control the total energy converter in all branches (both parallels and series) of each II arrange. At bottom level, the voltage balance of a converter branch, which comprises N H-bridge modules, is carried out by balancing (N-1) capacitor voltage deviations, with respect to the average capacitor voltage. The entire topology and control strategies are simulated in a PSIM environment. Simulation results with three H-bridge converters per branch are shown and preliminary experimental results with a low power prototype are also included., This work was supported by Fondecyt grant 1151325, CONICYT/FONDAP/15110019, The Spanish Ministry of Economy and EU FEDER funds under grant DPI2014-53245-R, The University of Magallanes grant PR-FI-02IE14/15, Universitat Jaume I grant P1.1B2013-51, the Newton Picarte Project EPSRC:EP/N004043/1 and CONICYT DPI20140007.

Optimized DC/DC converter loop compensation, which minimizes the number of large output capacitors, is described.

The LTC3414, a monolithic, synchronous step-down DC/ DC converter that is well suited for applications requiring up to 4A of output current, is described.

A buck-boost controller that simplifies the design of DC/DC converters for handheld products is described.

The LTC2400, a high accuracy differential to single-ended converter for ±5V supplies, is described.

The LT3470, a wide input voltage range, hysteretic mode, fully integrated monolithic 300mA step-down DC/DC converter, is described.

The use of a positive-to-negative voltage converter to achieve stable outputs even with a widely varying input is described.

The LT1304, a micropower DC/DC converter with independent low-battery detector, is described.

The LT1619 DC/DC converter, an ideal choice for a wide range of applications requiring low side MOSFET power transistors, high efficiency, low cost and high currents in very little board space, is described.

The LTC1702, a 2-phase dual switching regulator controller optimized for high efficiency with input voltage ranging from 2.7V to 7.0V, is described.

A single inductor, tiny buck-boost converter that provides 95% efficiency in lithium-ion to 3.3V applications is described.

A 1μA IQ synchronous boost converter that extends battery life in portable devices is described.

The simple LT3782 dual phase switching boost converter, which improves on single phase alternatives by allowing high power output with lower ripple currents, reduced heat dissipation and a more compact design, is described.

The use of the LTC1435A step-down DC/DC controller to optimize a DC/DC converter’s output capacitors is described.

The LT3759 controller is described. It operates over a wide input voltage range and controls positive and negative outputs using the same feedback pin, simplifying the design of power supplies that must be compatible with a wide array of power sources.

A unique high efficiency 12V converter that operates with inputs from 6V to 28V is described.

The LT3434, a wide input voltage range, 200kHz, monolithic 3A, step-down DC/DC converter, is described.

A wide input voltage range buck-boost converter that simplifies design of variable input supplies is described.

The aim of this chapter is to present a method of modeling switch-mode power supplies which allows establishing their transfer functions. On this basis, a classical control design methodology can be applied in order to achieve an output voltage regulation for instance. To do this, the average switch model, proposed by Middlebrook in 1976 at the IEEE Power Electronics Specialists Conference (PESC) and published in 1977, is used. For this, the switches in a switching cell (a transistor and a diode) are replaced by two equivalent sources (voltage and current) linked to the state variables (voltage at the capacitor terminals or current in an inductance) and to the constant sources in the system.

LT1374, a high efficiency 500kHz, 4.5A step-down converter in an SO-8 package, is described.

Four high performance, low cost, 1.75A step-down converter circuits based on the LT1076 five terminal switching regulator are described.

1.25Msps 12-bit analog-to-digital converter that cuts power dissipation and size is described.

The LT1618 DC/DC converter, which provides an accurate input current control ideal for USB applications, is described.

A low profile synchronous, 2-phase boost converter that produces 200W with 98% efficiency is described.

The LTC1174, a step-down converter that is designed specifically to eliminate noise at audio frequencies while maintaining high efficiency at low output currents, is described.

A negative buck converter, an easier way to generate an additional negative rail in systems that already have a larger negative voltage supply, is described.

The LTC1514/LTC1515 family of switched capacitor DC/DC converters, which offer a simple and cost-effective solution to low power step-up/step-down DC/DC conversion, are described.

A dual DC/DC converter with integrated Schottky diodes that generates ±40V outputs and consumes only 40μA quiescent current is described.

The LTC3811, which is a versatile, high performance synchronous buck controller optimized for low voltage, high current supply applications, is described.

The LTC3706 secondary-side synchronous controller and its companion smart gate driver, the LTC3725 are described. These two devices work together to make possible the creation of an isolated forward converter with the simplicity and performance of a buck converter.

The LT1316, a micropower step-up DC/DC converter with peak switch current control, is described.

The use of the LT3800 as the core of a single-supply synchronous DC/DC converter is discussed.

The LTC1265, a 14-pin SOIC step-down converter capable of operating at frequencies up to 700kHz, is described.

The newly released LTC1629, a dual current mode PolyPhase controller that provides a cost-effective solution for low voltage, high current applications, is described.

The LTC1876, which can efficiently power low voltage DSPs, ASICs and FPGAs from a low input voltage, is described.

The LT3430, which features a 3A peak switch current limit, 100mΩ internal power switch and a 5.5V to 60V operating range, is described.