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Coupling output inductors is a very popular solution when designing a multiple-output DC/DC system. Space-borne circuits are one of the areas where a custom DC/DC converter design with coupled inductors could be preferred to have a detailed design of all variables. Output voltage regulation can be improved using coupled output inductors on a multiple-output DC/DC converter, and, as demonstrated in this paper, it provides an enhanced stability. This paper presents the small signal analysis of a push-pull converter with seven outputs having all its output inductors coupled together and compares it theoretically to the uncoupled version to demonstrate the stability improvement. The theoretical results are validated by simulating a linear model of the circuit and measuring the frequency response on an experimental prototype. Design guidelines and additional benefits of output-coupled inductors are also listed. [ABSTRACT FROM PUBLISHER]

The positive output elementary superlift-Luo converter (POESLLC) is a type of dc/dc converter. This dc/dc converter has an attractive advantage of a high voltage transfer gain as compared with other conventional dc/dc converters. Because of the voltage and load variations and also switching operation, the dynamic and static performances of the POESLLC are nonlinear and time varying. In order to achieve an excellent performance, a nonlinear controller is required. In this paper, a robust and fast response controller for voltage regulation of a POESLLC is presented. A proportional integral and pulse width modulation sliding mode controller are combined to control a third-order POESLLC. The proposed controller can be applied in the continuous conduction mode. Some simulations and experimental results are presented to show the effectiveness of the developed controller in different operating conditions. Furthermore, it will be shown that the developed controller is successful in suppressing the steady-state error of the output voltage of the POESLLC as well as the number of reduction of sensors. [ABSTRACT FROM PUBLISHER]

This paper presents a transformerless ac-dc and or dc-dc converter with a high output voltage multiplicity, which contains only one switch. The converter consists of an inverter and a diode-capacitor multiplier (DCM) and provides a voltage gain equal to double the number of multiplier steps. In the case of ac-dc conversion the proposed converter otters a practically unit power factor and provides a sine wave input current. The analysis of the steady state as well as the transient behavior of the DCM is given and simplified equivalent circuits are proposed. The prototype of the DCM has been built and tested to show the validity of the proposed converter. The theoretical analysis, the computer simulation results, and the experimental testing results are in good agreement. [ABSTRACT FROM AUTHOR]

A modular three-port converter-based spacecraft power system is analyzed. To achieve power management of the distributed power system, a novel hybrid power control strategy is proposed, that is, current sharing control on the battery port when the battery discharges and power distribution based on the ability of sources when the battery charges.With the proposed power control, reliable and stable operations of the system within all of the conditions can be achieved. The experimental results demonstrate the feasibility of the proposed power control strategy. [ABSTRACT FROM AUTHOR]

Provides a method for modeling switch-mode direct current-to-direct current cascade converters. Basic switch-mode pulsewidth modulation; Nonlinear models for cascade connection; Linear models for cascade connection.

A novel DC-DC power converter has been developed to fulfill the requirements of a solar electrical propulsion module. The maximum power point tracker solar array regulator is divided into two series converters; a direct-energy transfer (DET) regulator and a secondary step-up converter. The DET regulator creates an unregulated maximum power point bus and the secondary converter regulates to a 100-V bus. The purpose of this paper is to describe the solution with a specific design and experimental results. [ABSTRACT FROM PUBLISHER]

A dc/dc converter for power distribution aboard the International Space Station (ISS) and space vehicles employing the 120 V dc bus is proposed. It is well suited to supply power to multiple loads including peripheral low voltage point-of-load (POL) regulators. The dc/dc converter is phase-shift controlled at the constant frequency of 500 kHz. The topology is characterized by distribution in a sequence of 4 metal-oxide semiconductor field-effect transistors (MOSFETs), switched ON at zero voltage. The linear model has first-order dynamics. Responses to small and large load variations benefit from its advantageous control features. A peculiar characteristic is its high dynamic independence of load typology and output power. To focus on this quality, dynamic performances are investigated through analyses, simulations, and measurements considering three types of loads: constant current, resistive, and constant power. Experimental data from a 100 W prototype fit the model forecasts well. [ABSTRACT FROM AUTHOR]

A stability analysis for a maximum power point tracking (MPPT) scheme based on extremum-seeking control is developed for a photovoltaic (PV) array supplying a dc-to-dc switching converter. The global stability of the extremum-seeking algorithm is demonstrated by means of Lyapunov's approach. Subsequently, the algorithm is applied to an MPPT system based on the ‘perturb and observe’ method. The steady-state behavior of the PV system with MPPT control is characterized by a stable oscillation around the maximum power point. The tracking algorithm leads the array coordinates to the maximum power point by increasing or decreasing linearly with time the array voltage. Off-line measurements are not required by the control law, which is implemented by means of an analog multiplier, standard operational amplifiers, a flip-flop circuit and a pulsewidth modulator. The effectiveness of the proposed MPPT scheme is demonstrated experimentally under different operating conditions. [ABSTRACT FROM AUTHOR]

We develop analytic methodologies for stability analyses (using nonlinear and linear methodologies) of parallel dc-dc converters (under unsaturated and saturated operating conditions) using their switching model, discrete model (based on nonlinear map), and averaged model. We describe the approach for investigating the behavior of the stable and unstable equilibrium solutions of a parallel dc-dc converter under parametric variations and illustrate the methodology using a load-sharing dc-dc buck converter. For unsaturated operating condition, using bifurcation analysis and Floquet theory, we predict the stability boundary of the nominal solution, determine its postinstability dynamics, and investigate the dependence of the converter dynamics on its initial conditions. Subsequently, we demonstrate the differences in the predictions of the instabilities and instability boundaries using (conventional) linearized averaged (small-signal) and discrete and switching models. [ABSTRACT FROM AUTHOR]

Hybrid fuel cell/battery power sources have potentially widespread uses in applications wherein the power demand is impulsive rather than constant. Interposing a dc/dc converter between a fuel cell and a battery can create two configurations of actively controlled hybrid fuel cell/battery power sources. Those two configurations are compared using both theory and experiment with special attention to the peak power enhancement, and power losses in the converter. Both of the defined configurations were built, using a 35 W polymer electrolyte membrane (PEM) fuel cell, an 8-cell lithium-ion battery pack, and a high-efficiency power converter. Both two configurations yielded a peak power output of 135 W, about 4 times as high as the fuel cell alone could supply, with only a slight (13%) increase of weight. The converter losses were quantitatively analyzed. Which of the two configurations yields a smaller loss depends on the load power demand characteristics including peak power and load duty ratio. The study results provide guidance for the design of hybrid sources according to the particular load power requirements. [ABSTRACT FROM AUTHOR]

A novel high-frequency transformer linked full-bridge type soft-switching phase-shift pulsewidth modulated (PWM) controlled dc-dc power converter is presented, which can be used as a power conditioner for small-scale photovoltaic and fuel cell power generation systems as well as isolated boost dc-dc power converter for automotive ac power supply. In these applications with low-voltage large-current sources, the full-bridge circuit is the most attractive topology due to the possibility of using low-voltage high-performance metal-oxide-semiconductor field-effect transistor (MOSFET) and achieving high efficiency of the dc-dc power converter. A tapped-inductor filter including the freewheeling diode is newly implemented in the output stage of the full-bridge phase-shift PWM dc-dc converter to achieve soft-switching operation for the wide load variation range. Moreover, in the proposed converter circuit, the circulating current is effectively minimized without using additional resonant circuit and auxiliary power switching devices, The practical effectiveness of the proposed soft-switching dc-dc power converter was verified in laboratory level experiment with 1 kW 100 kHz breadboard setup using power MOSFETs. Actual efficiency of 94-97% was obtained for the wide duty cycle and load variation ranges. [ABSTRACT FROM AUTHOR]

Pulse Train™ control scheme is presented and applied to a boost integrated flyback rectifier/energy storage dc-dc (BIFRED) converter operating in discontinuous conduction mode (DCM), which avoids the light-load high-voltage stress problem. In contrast to the conventional control techniques, the principal idea of Pulse Train technique Is to regulate the output voltage using a series of high and low energy pulses generated by the current of the inductor. The applicability of the proposed technique to both the input and magnetizing inductances of BIFRED converter is investigated. Analysis of BIFRED converter operating in DCM as well as the output voltage ripple estimation are given. Experimental results on a prototype converter are also presented. [ABSTRACT FROM AUTHOR]

A robust model-following (RMF) control technique for average current mode controlled (ACC) parallel buck dc-dc converters, RMFACC, is presented. RMFACC achieves that the loop gain of the voltage loop is little sensitive to the variation of power number of modules, input voltage, load, and component tolerances. The design of the voltage loop is `decoupled' from the design of the disturbance rejection transfer functions in an important degree, so that the output impedance and audiosusceptibility are greatly reduced without the need of high loop gain crossover frequencies. A comparative study between conventional ACC and RMFACC is shown. [ABSTRACT FROM AUTHOR]

An evolutionary approach to worst case tolerance design is introduced here, with a focus on feedback compensation networks for dc-dc switching converters. Assumed that varying parameters values are uniformly distributed and uncorrelated., as provided by the worst case approach, the proposed algorithm, of general applicability, seeks for the set of nominal values and tolerances of the circuit parameters ensuring that the design constraints are met and that a user-defined circuit performance index assumes its optimal value. Design constraints are fixed in the frequency domain, in terms of acceptability ranges of loop gain crossover frequency and phase margin, to guarantee closed loop stability and the desired dynamic performance. Resistive and capacitive compensation network's parameters values are chosen within a suitable database of couples nominal value/tolerance available on the market, while the nominal values and tolerances of the parameters of the power stage are fixed. Referring to a buck dc-dc switching regulator, two widely used different compensation network topologies are compared in terms of reliability, robustness, and cost of components. Simulation results show the wide usefulness of the proposed method in supporting designer decisions. [ABSTRACT FROM AUTHOR]

Presents the theoretical and practical details involved in the control design and closed-loop analysis of a step-down switched-capacitor (SC) direct-current-to-direct-current (DC-to-DC) converter. Schematic diagram of the step-down SC DC-to-DC converter; Analysis of the power stage dynamics of the SC converter; Feedback compensation design and closed-loop performance.

Proposes a three-phase dc-to-dc LCC-type resonant converter with high-frequency transformer isolation. Advantages of LCC-type resonant converter (SPRC); Analysis of the converter; Advantages of the proposed converter; Presentation of Space Integrated Control Experiment (SPICE) simulation and experimental results for the designed converter.

Presents the front cover/table of contents for this issue of this publication. [ABSTRACT FROM PUBLISHER]

The design and development of a dc to dc buck converter capable of operating up to 275?C is presented. The control circuitry design is based on the vee-square (V^2) control mechanism. The system converts a raw dc input voltage in the range of 15 V to 25 V to a stepped-down and filtered output voltage in the range of 1.5 V to 18 V. A custom designed user programmable control circuitry is implemented on the low leakage, radiation tolerant silicon-on-insulator technology. Silicon carbide junction field effect transistors (JFETs) are used as power switches to sustain extreme operating temperature. The system is prototyped on the aluminum nitride substrate to meet packaging requirements. Design considerations for the planar transformer coupled gate drive are specifically addressed. The system performance is studied based on a 20 V to 3.3 V prototype converter. The demonstrated system has potential market in extreme environment applications like deep space explorations, down-hole geothermal and deep gas reservoir management, etc. [ABSTRACT FROM PUBLISHER]

The design and results of a high-efficiency high-power (5 kW) nonisolated bidirectional dc-dc converter is presented. High stability due to minimum phase behavior is an additional benefit of the topology. The converter is a new boost with output filter where input and output inductors are coupled. This converter is useful with any system that needs to charge and discharge backup batteries and can be applied in space, automotive, and telecom power systems. [ABSTRACT FROM PUBLISHER]