Showing papers on "Buck–boost converter published in 1995"

Single-phase three-level boost power factor correction converter

Abstract: In many single-phase power factor correction (PFC) applications, the power level can reach several kilowatts; and in some situations, the input voltage can be quite high too. For high power and/or high voltage applications, the major concerns of the conventional boost PFC converter are the inductor volume and weight, and losses on the power devices, which will affect converter cost, efficiency, and power density. In this paper, a three-level boost converter is adopted for single-phase PFC, which uses a much smaller inductor and lower voltage devices than the conventional boost PFC converter does, yielding high power density, high efficiency, and low cost. >

DC-DC converter design for battery-operated systems

Abstract: This paper describes performance, design and optimization of DC-DC converters for energy limited, battery operated systems. Variable-frequency operation is used to achieve voltage regulation and high efficiency for an extremely wide range of load currents. An experimental 15 W, 3.3 V buck converter has been constructed to demonstrate design and optimization techniques. The converter employs synchronous rectification to reduce conduction losses, and discontinuous, variable-frequency, current-mode control with optimum peak current to maximize efficiency for a wide range of loads. Applications include portable computers, hand-held instruments, and telecommunications. >

Full range soft-switching DC-DC converter

Abstract: A soft-switching DC to DC power converter which minimizes switching losses from a no load condition to a full load condition while operating at fixed frequency. Output voltage control is achieved by controlling the phase angle between the two switching networks. High frequency transformer primaries are always excited with a square wave input voltage equal to ##EQU1## The power converter can be implemented with a single transformer. Moreover, the switch voltage never increases the input DC voltage from no load to full load. The power converter can be used in both low voltage high current applications and high voltage low current applications.

20 kW water-cooled prototype of a buck-boost bidirectional DC-DC converter topology for electrical vehicle motor drives

Abstract: In brushless DC motor drives devoted to electric vehicles (EVs) a bi-directional DC-DC power converter can be used to control suitably both motoring and regenerative braking operations in order to improve the motor drive performance. In consideration of such an application, this paper deals with the experimental study of a buck-boost bi-directional DC-DC power converter topology which has been conceived for the use in EVs propelled by means of wheel-direct-coupling axial-flux PM motor drives. The paper discusses the power converter modes of operation and reports experimental results taken from a 20 kW water-cooled prototype of the proposed power converter topology. >

An overall study of the half-bridge complementary-control DC-to-DC converter

Abstract: The half-bridge complementary-control power converter has been recently proposed as a low-output voltage DC-to-DC power converter due to its excellent features (efficiency around 90% at as low an output voltage as 33 volts) A study of the statics and dynamics of this power converter is proposed in this paper Thus, DC voltage conversion ratio both in continuous and discontinuous conduction mode, the boundary between both modes, the DC current level in the transformer and a small-signal average model have all been obtained From the latter, transfer functions between duty cycle and output voltage and between input and output voltages have been also obtained, and some simplifications and design rules have been proposed to facilitate the design of the feedback loop >

High efficiency resonant switching converters

Abstract: Resonant DC to DC power converter topologies include a PWM-controlled flyback converter having a single transformer and a primary side resonant subcircuit that is optimally controlled to minimize reverse recovery losses. A second transformer may be added wherein the primary windings are connected in series, the first transformer having substantially greater inductance than the second transformer to more efficiently transfer energy over a wide range of output load conditions. A combined forward-flyback resonant converter utilizing a load-side buck loop for increased power delivery performance and start-up circuitry for initial power connection of the converter to a voltage source utilizing a hysteresis protection circuit are also disclosed.

Transient voltage protection circuit for electrical power converters

Abstract: A transient over-voltage protection circuit includes a normally closed switch connected between a rectifier circuit and a DC to DC converter. This switch is caused to partially open when the voltage input to the DC to DC converter exceeds a predetermined value, thereby protecting the DC to DC converter from input voltages that exceed the converter's operational limits. The switch is returned to its normally closed state when the level of voltage input to the converter drops below a predetermined lower value. A capacitor connected across the input terminals of the converter is charged up when the switch is closed and functions to supply power to the DC to DC converter when the switch is in its partially opened or current limit state.

A three-switch high-voltage converter

Abstract: A novel three-switch HV converter derived from the Cuk converter is presented. This converter can operate into a capacitor-diode voltage multiplier, which offers simpler structure and control, higher efficiency, reduced EMI, size and weight savings than traditional switched-mode regulated voltage multipliers. Two significant advantages are the continuous input current and easy isolation extension. The new converter is experimentally verified. Both the steady state and dynamic theoretical models are correlated well with the experimental data. >

Small-signal modeling of soft-switched asymmetrical half-bridge DC/DC converter

Abstract: A small-signal model of soft-switched asymmetrical half-bridge DC/DC converter operating in a continuous inductor conduction mode is proposed. The analysis of this model is applicable to converters with any type of output rectifier (full-wave or half-wave). Based on the proposed model, the feedback compensation network for a prototype converter was designed. An open loop frequency response and voltage ripple attenuation of the converter with closed feedback loop were calculated. The experimental results validated all theoretical predictions. >

An LCL resonant converter with PWM control-analysis, simulation, and implementation

Abstract: A three element resonant converter capable of driving a voltage type load with load independent operation is analyzed using a state-space approach. Pulse width modulation is employed to control and regulate the output voltage. Closed-form solutions are obtained under steady state conditions. The experimental study of a prototype converter reveals complete agreement with the analytical and SPICE simulation results. Typical experimental oscillograms are given to verify the basic principles. >

Control of power factor correcting boost converter without instantaneous measurement of input current

Abstract: This paper proposes a new control method for the constant-frequency control of power factor correcting boost power converter using a sinewave template modulated PWM signal which eliminates the need for instantaneous measurement of the line current for the switching control of the boost converter. The control strategy is based on the notion that the line current can be forced to trace a deterministic waveform such as a sinusoid by considering the implicit model of the sinewave in the boost converter controller structure. The modulating sinewave template is generated using the line voltage, the boost converter output voltage and the load current. The paper provides the analysis and the design of the controller and presents simulation and implementation results to demonstrate its effectiveness. >

Circuit and method for achieving zero ripple current in the output of a converter

Abstract: A power converter and a method of operating a power converter. The power converter includes: (1) a transformer for receiving bipolar electrical input power from a power source, the power substantially free of dead time and (2) a hybridge rectifier coupled to the transformer and including first and second output inductors of independently selectable, differing inductance, the hybridge rectifier receiving the input power from the transformer and rectifying the input power to produce an output power substantially free of ripple current at a predetermined duty cycle operating point of the converter, the first and second output inductors being of independently selectable, differing inductance thereby to allow the predetermined duty cycle operating point to be adjustable.

Boost converter power supply with reduced losses, control circuit and method therefor

Abstract: A boost converter power supply circuit (11) uses energy from a diode recovery current (Id5) which flows in a blocking diode (D5) at diode commutation to discharge a capacitance associated with the main switch (S1) of the boost converter (11) in order to achieve zero voltage switching The diode recovering current (Id5) is initially captured in an inductor (L2), is then transferred to a capacitor (C2), and is then transferred back to the inductor (L2) prior to the main switch (S1) being switched on

Differential to single-ended CMOS converter

Abstract: A differential-to-CMOS level signal converter which receives a first differential signal having a small amplitude difference between the binary signals. The differential-to-CMOS level converter amplifies and level shifts the binary differential signal and outputs a single-ended CMOS level signal suitable for use by digital CMOS logic. A circuit for biasing the differential-to-CMOS level converter is coupled to the level shifting circuitry.

A three-phase series-parallel resonant converter-analysis, design, simulation, and experimental results

Abstract: A three-phase DC-to-DC series-parallel resonant converter is proposed and its operating modes for a 180/spl deg/ wide gating pulse scheme are explained. A detailed analysis of the converter using a constant current model and the Fourier series approach is presented. Based on the analysis, design curves are obtained and a design example of a 1-kW converter is given. SPICE simulation results for the designed converter and experimental results for a 500-W converter are presented to verify the performance of the proposed converter for varying load conditions. The converter operates in lagging power factor (PF) mode for the entire load range and requires a narrow variation in switching frequency, to adequately regulate the output power.

Current-source parallel-resonant DC/DC converter

Abstract: This paper introduces, analyzes, and experimentally verifies a novel DC/DC converter called the current-source parallel-resonant converter. The converter consists of a large choke inductor, two switches, and a parallel-resonant circuit. Each switch consists of a MOSFET in series with a diode. It has a nonpulsating input current with a very low AC ripple. The MOSFETs are driven with respect to ground and, therefore, have a simple gate-drive circuit. The analysis of the converter is carried out in the frequency domain using Fourier series techniques. Analytical expressions are derived for performance parameters of the converter. A prototype of the converter circuit was designed, built, and tested. The theoretical results were in good agreement with the experimental results. >

Full wave buck-boost power converter with buck power converter properties

Abstract: A continuous mode full wave power converter topology which integrates the buck-boost (flyback) and buck converter properties. The voltage transfer function is M = (D/(1-D)), characteristic of the buck-boost (flyback) converter. Characteristic of the full wave buck converter, the inductor current is source continuous during the alternate D intervals, source discontinuous during the simultaneous (1-D) intervals, and load continuous during both the D and (1-D) intervals. A continuous mode full wave power converter topology which integrates the buck-boost (flyback) and buck converter properties. The voltage transfer function is Eout = Ein (D/(1-D)), characteristic of the buck-boost (flyback) converter. Characteristic of the buck converter, the inductor current is source continuous during the alternate D intervals, source discontinuous during the simultaneous (1-D) intervals, and load continuous during both the D and (1-D) intervals.

Digital control of a ZVS full-bridge DC-DC converter

Abstract: The paper describes the design and realization of a digital controller for a DC-DC power converter with zero-voltage switching (ZVS). The chosen power converter, usually called the phase-shifted bridge, is valuable because it combines advantages from both conventional PWM and resonant-mode power converters. It is therefore an important topology for investigating the advantages of digital control for DC-DC power converters. The power converter's control equations are nonlinear. The paper explains how the digital technique simplifies the separation of large-signal and small-signal control of the power converter. The loop updates at 25 kHz, and experimental results show the dynamic response achieved. >

Charge redistribution analog-to-digital converter with system calibration

Abstract: A charge redistribution analog-to-digital converter. This converter includes an offset correcting circuit operatively connected in parallel with a capacitor array and responsive to a sampling input of the analog-to-digital converter, and a gain correcting circuit operatively connected in parallel with a sampling capacitor and responsive to the sampling input of the analog-to-digital converter. In another general aspect, an analog-to-digital converter calibration method for a charge redistribution analog-to-digital converter, that includes adjusting an input offset of an input of the analog-to-digital converter and adjusting a gain offset of the analog-to-digital converter. The steps of adjusting are then repeated until a predetermined level of error is achieved for the analog-to-digital converter.

Voltage-follower control in zero-current-switched quasi-resonant power factor preregulators

Abstract: In this paper, we propose to study the use of several zero-current-switched (ZCS) quasi-resonant converters (QRCs) (buck-boost, flyback, SEPIC, Cuk, boost, and buck) with a half-wave switch, working as power factor preregulators (PFPs) with voltage-follower control. The analysis carried out demonstrates that these converters show excellent characteristics to obtain a high power factor (PF) without using any input-current feedback loop, and they also allow high switching frequency to operate because they integrate transformer and rectifier diode parasitics into the power topology.

Converter based solution to power quality problems on radial distribution lines

Abstract: In this paper, the authors show that the power converter-based Power Quality Manager (PQM) is a viable solution to power quality problems on radial power distribution lines. The PQM is capable of simultaneous harmonic isolation, improving voltage regulation and flicker compensation. These functions can also be implemented independently. The PQM is a hybrid device comprising passive components and a power converter. The converter power rating is lower than that required by an equivalent active filter or power converter-based static VAr compensator.

Control of chaos in the boost converter

Abstract: A method for controlling chaos which is particularly suitable for switching circuits is presented. The method has been successfully applied to the current-mode controlled boost converter which is a piecewise linear system with switching nonlinearity.

Robust control of DC-DC converters: the buck converter

Abstract: Under different input voltage and output load conditions, the dynamics of the buck converter changes. In this paper, we use a structured uncertainty model to describe the dynamic behavior of the buck converter for voltage mode control. For the current mode control case, we use an unstructured multiplicative uncertainty model to capture the family of perturbed small signal dynamics of the buck converter. The powerful Kharitonov's theorem and the LQG/LTR technique are then utilized to design robust controllers to achieve robust stability and performance for the voltage mode controlled and current model controlled buck converters respectively. >

The Zero Voltage Switching Partial Series Resonant Converter

Abstract: A new high-frequency dc to dc converter, suitable for application in the kilowatt range, is presented. The topology is based on a half bridge series resonant converter, i.e., having only two switches. Resonance occurs only for a part of each switching cycle, and a discrete energy pulse is transferred to the load every half cycle, rendering a variable frequency controller for controlling the output power. The converter features zero-voltage turn-on, and snubbed turn-off at reduced current for the switching devices, and zero current commutation of the rectifier diodes, making it suitable for IGBT switches operating at a switching frequency higher than 20 kHz. The efficiency of the converter is very high under full load and low load conditions, while the dynamic output voltage range is two times larger than that of the conventional half bridge Series Resonant Converter.

Boost-buck push-pull converter for very wide input range single stage power conversion

Abstract: In many avionics systems, the power supply is required to operate over a very wide input voltage range In these aircraft systems the power supplies are powered off a permanent magnet generator (PMG) The PMG, which is typically mounted via a gear box to the engine of the aircraft, outputs a voltage proportional to the speed of the engine It is usually required to have the avionics start at very low engine speeds and operate up to the maximum engine speeds To operate over this large input range, power converter stages are cascaded to reduce the input range down to manageable levels The last converter stage then provides the filtering, isolation, scaling and regulation for the avionics system Additionally, aircraft power sources are provided for backup power and typically require power factor correction Active power factor correction is also performed with a separate cascaded pre-regulator converter Multiple power conversion stages reduce efficiency, increase cost, and increase size of the power supply system The power converter described combines the aforementioned functions into a single conversion stage The converter is a push-pull converter that has both buck and boost regulator characteristics At low input voltage the push-pull converter acts as a boost, and at high input voltages it acts as a buck converter For power factor correction applications, this push-pull converter, by transitioning between the boost and buck operating modes, is able to shape the input current >

A novel method to achieve zero-voltage regulation in buck converter

Abstract: The function control law for a buck converter is derived to achieve zero voltage regulation of the output voltage. A new method to retrieve the low frequency component of the inductor voltage is proposed and analyzed. The stability of the closed loop system using a proportional and differential controller is analyzed. The effect of the supply voltage and load current disturbance is also studied. The analysis, computer simulation by PSPICE and experimental results illustrate that excellent performance can be achieved by the function control law. >

A new instantaneous-current controller for three-phase buck-boost and buck converters with PFC operation

Abstract: A new instantaneous-current controller for three-phase buck-boost and buck power converters with power factor correction (PFC) operation is proposed. Based on the idea of a three-phase equivalent pulse-current-source with delta-form, the controller simply generates three-phase switching-patterns for PFC operation. Additionally, the controller employs a pulse-space-modulation technique to compensate modulation errors caused by ripples in the DC-inductor current and to reduce the size of the inductor. The modulation technique is further extended to realize a discontinuous-switching scheme to reduce switching losses. The paper describes the theory and the implementations. To show the validity of the theory, experimental waveforms, spectra and static characteristics, obtained by a 3 kW setup are introduced. Finally, conclusions are drawn and abilities and problems for future study are described. >

77 K operation of a multi-resonant power converter

Abstract: The liquid-nitrogen temperature (77 K) operation of a 55 W, 200 kHz, 48/28 V zero-voltage switching multi-resonant DC/DC converter designed with commercially available components is reported. Upon dipping the complete converter (power and control circuits) into liquid-nitrogen, the converter performance improved as compared to the room-temperature operation. The switching frequency, resonant frequency, and the characteristic impedance did not change significantly. Accordingly, the zero-voltage switching was maintained from no-load to full-load for the specified line variations. Cryo-electronics can provide high density power converters, especially for high power applications. >

Analog-to-digital converter and sensor device comprising such a converter

Abstract: The present invention relates to a periodically integrating analog-to-digital converter and a sensor device comprising such a converter. The analog-to-digital converter comprises a measured-value-to-pulse-amount converter, i.e. a sigma-delta converter of the first order that is reset to zero before each new period, and a digital counter for the number of feedback signals of known reference value in the measured-value-to-pulse-amount converter. This constitutes a rough measure of the input signal. It further comprises an analog-to-digital converter which converts the residual value of the measured-value-to-pulse-amount converter at the end of the period to a digital value, and an adder which adds this value to the output signal from the digital counter, resulting in a more accurate measure of the input signal.

A fixed frequency LCL-Type series resonant converter

Abstract: A fixed frequency LCL-type series resonant converter (SRC) which uses an inductive output filter is proposed. Steady-state analysis of the converter is presented using complex ac circuit analysis. Based on the analysis, a simple design procedure is given. Detailed space integrated control experiment (SPICE) simulation results are presented to evaluate the performance of the designed converter under varying load and supply voltage conditions. Also, detailed experimental results obtained from a metal-oxide-semiconductor field-effect transistor (MOSFET) based 500 W converter are presented to verify the analysis and SPICE simulation results. The results obtained from the analysis, SPICE simulation and the experimental converter are compared. The proposed converter requires a narrow variation in pulsewidth while maintaining lagging power factor mode of operation for a very wide variation in the load as well as supply voltage. >