Showing papers on "Boost converter published in 1990"

Zero-voltage switching technique in DC/DC converters

Abstract: A novel resonant switch operating under the principle of zero-voltage switching is presented. The basic configurations of the voltage-mode resonant switches are presented. The circuit's operating principles are described using a voltage-mode quasi-resonant boost converter. DC analysis of the converter is carried out. A new family of voltage-mode quasi-resonant converters are derived, and several members of this family are presented. The duality relationship between the zero-current switching technique and the zero-voltage switching technique is derived. These two techniques are compared using an example showing the duality between a current-mode quasi-resonant Buck converter and a voltage-mode quasi-resonant boost converter. The similarities and differences of the voltage-mode quasi-resonant converters and the Class-E converters are discussed. A 5 MHz 50 V to 5 V flyback converter employing the zero-voltage switching technique has been implemented. Design considerations and experimental results of this circuit are presented. >

A novel soft-switching full-bridge DC/DC converter: Analysis, design considerations, and experimental results at 1.5 kW, 100 kHz

Abstract: The authors present an improved soft-switching full-bridge converter which is especially suitable for high-power application (e.g. more than 1 kW output) because of its inherently high efficiency. The addition of an external commutating inductor and two clamp diodes to the phase-shifted PWM (pulse width modulation) full-bridge DC-DC converter substantially reduced the switching losses of the transistors and the rectifier diodes, under all loading conditions. The authors analyze the conditions for lossless transitions, discuss the effect of the added components on the operation of the converter, and present practical considerations and test results for a 1.5 kW converter with 100 kHz clock frequency. The converter has an efficiency above 95% at 60 V output, is free from voltage overshoots, and exhibits well-controlled transitions for all switch and rectifier voltages and currents. >

A two switch high performance current regulated DC/AC converter module

Abstract: A high-performance current regulated single-phase DC/AC converter module is proposed in this paper. Its novel features include: a two-switch topology with no "shoot-through" paths, high input to-output voltage gain, low and constant switching frequencies, and practically instantaneous recovery from input or output transients. Moreover, by utilizing an inner filter capacitor current control loop the proposed module can maintain nearly perfect sinusoidal output voltages even with highly nonlinear loads. Furthermore, three-phase operation can be obtained easily by using three of these modules. Finally, the paper includes the analysis and design of the converter power and control circuits and the experimental evaluation of key predicted results. >

Sinusoidal line current rectification at unity power factor with boost quasi-resonant converters

Abstract: A sinusoidal line current rectifier is considered at unity power factor, where the conventional boost converter, usually utilized between the diode rectifier bridge and the DC bus capacitor, is replaced with a boost zero-current switching quasi-resonant converter (boost ZCS-QRC). The zero-current switching quasi-resonant rectifier (ZCS-QRR) is analyzed theoretically. Normalized curves are plotted, and equations that allow high flexibility in design are developed. A design example is proposed, and experimental results are presented to demonstrate the operating principle, the feasibility of the technique, and the validity of the theoretical analysis. >

Analysis and design of a series-parallel resonant converter with capacitive output filter

Abstract: The objectives are to propose a LCC-type parallel resonant power converter with a capacitive output filter, to present its different operating modes and analyze the converter for these modes, to obtain design curves based on the analysis to present a simple design procedure for the proposed converter, and, finally to provide experimental results. A high-frequency link series-parallel resonant power converter with capacitive output filter is proposed and analyzed using the state-space approach. Analysis shows that the converter enters into three different modes. The normalized load current and other component stresses are plotted against the converter gain. Detailed experimental results are presented to verify the theory. >

A 500 kHz multi-output converter with zero voltage switching

Abstract: A detailed analysis of topological modes of the converter and its relation to the design, development, and performance of a multioutput prototype converter are given. The implemented topology is found to be a good solution for eliminating converter switching losses at high frequencies. The breadboarded converter demonstrates the zero voltage switching very clearly, resulting in improved efficiency. The implementation of the circuit was relatively simple and was not susceptible to noise problems associated with high-frequency converters. >

Inductor shunt, output voltage regulation system for a power supply

Abstract: High efficiency, post regulation of auxiliary outputs in multiple output-power supplies is provided by connecting a regulating switching device in parallel with a filter inductor connected in the current path from the rectifiers to the output terminal. For minimum output power for that auxiliary output, the switching device is held off at all times. When increased power is required, the switching device is turned on for a short period during each cycle of the inductor voltage. The switching system may be configured to conduct current from the output end of the inductor to the input end of the inductor or vice versa or either one selectively, in accordance with the particular regulation scheme chosen. Efficiency is maximized since current flows in the switching device for only a small portion of the cycle of the inductor voltage.

Application of magnetic energy storage unit as continuous VAr controller

Abstract: It is shown that magnetic energy storage units can simultaneously operate as continuous VAr (volt-ampere reactive) controllers while performing the role of load-frequency stabilizers in electrical power systems. This is achieved by operating the converter in the buck-boost mode with a switched capacitor bank placed across its terminals. The P versus Q modulation ranges of the 12-pulse converter depend on the source inductance, secondary voltage of the input transformers, and output current. Once the input transformer is chosen, the Q modulation range depends on the active power transfer and the current through the inductor at any instant of time. The actual reactive power consumption of the converter is varied continuously, depending on the requirements of the power system, while keeping within the Q-modulation range. Switching of the capacitor bank keeps the required Q consumption of the converter within the available range. It is shown that this mode of control improves the overall performance of the power system in P-f and Q-V loops and obviates the use of any additional VAr compensator in the power area where the SMES (superconducting magnetic energy storage) unit is located. >

Constant frequency resonant DC/DC converter

Abstract: A constant frequency full resonant mode dc/dc converter is provided, suitable for use in low voltage, high current dc power distribution systems. The converter comprises a full-bridge inverter, a resonant circuit, an output transformer, an output diode rectifier, a dc output filter, and a control circuit. The resonant circuit consists of a series branch and a parallel branch. The components of the series branch are selected such that close-to-maximum voltage gain and a near load independent output voltage of the converter are achieved. The components of the parallel branch are, however, chosen to obtain an overall lagging current at the output of the full-bridge for a desired range of output voltage control and no-load to full-load operating conditions.

Battery pack including electronic power saver

Abstract: A housing (11) of a battery pack (10) contains in addition to standard power cell elements (14-16) a voltage converter (75). The voltage converter (75) is interposed between the power cell elements (14-16) and external output contacts (29, 30, 100) of the housing (11). The voltage converter (75) regulates the output voltage applied to the output contacts (29, 30, 100) of the battery pack (10), such that the supply voltage of the battery pack (10) remains at a predetermined value which is independent of the voltage supplied by the power cell elements (14-16) to the voltage converter (75) and does not vary over the discharge cycle of the power cell elements (14-16). Excess battery voltage available particularly during the initial portion of the discharge cycle of the power cell elements (14 - 16) is efficiently converted to the predetermined output voltage value which reduces the overall current delivered by the power cells (14-16) to extend the useful life of the battery pack (10) between charges.

New switched-capacitor DC-DC converter with low input current ripple and its hybridization

Abstract: A switched-capacitor (SC) DC-DC converter is developed to reduce the input current ripple and to achieve miniaturization A fixed-capacitor added to an original SC reduces the input current ripple This converter is miniaturized by a copper thick-film hybrid technique The features of this converter are as follows: (1) low input current ripple (one third compared with that of original SC DC-DC converters), (2) very high efficiency (90%), and (3) very high power density (23 W/in/sup 3/ in the 10 W class) >

Power conversion apparatus with harmonic filtration

Abstract: A power conversion apparatus capable of eliminating inexpedient higher harmonic components from its output, without lowering the conversion efficiency. The apparatus includes a first power converter for converting an input power from a power supply into an output power; a detector for detecting an output current and an output voltage of the first power converter; a high harmonic detector for detecting a higher harmonic component on a basis of the output current and the output voltage, and for producing current reference signal corresponding to the detected higher harmonic component; and a second power converter for producing an inverse of the detected higher harmonic component according to the current reference signal, and combining the produced inverse of the higher harmonic component with the output current of the first power converter such that the higher harmonic component in the output current of the first power converter are cancelled by the inverse of the higher harmonic component.

Zero-voltage resonant transition switching power converter

Abstract: A single-ended DC-to-DC power converter which is operative at very high switching frequencies with zero-voltage resonant transition switching. A single magnetic element functions as both a storage inductor and a transformer. A charging capacitor is switched to induce a reversal current through the inductor for providing the zero-voltage switching function. Control to output characteristics are identical to those of conventional buck and buck-boost converters. The invention provides efficient, high-frequency operation and isolation of the output from the input power source with minimal component volume. The control system is adaptable to constant frequency pulse width modulation for voltage regulation.

Switched capacitor interleaved forward power converter

Abstract: A DC-to-DC power converter topology utilizing parallel connected transformers in a buck switching configuration with each stage operated 180° out-of-phase, with the primary windings of the transformers sequentially feeding into a common filter capacitor. On each transformer, a secondary winding is switched to a load at the time the primary winding is shunted across the filter capacitor. The circuit provides dual inductor buck power stage operation while maintaining input-output isolation. Interleaved power processing provides continuous capacitance support for the output voltage produced by the power supply.

Internal voltage converter in a semiconductor integrated circuit

Abstract: An internal voltage converter of a semiconductor integrated circuit according to the invention comprises an oscillator 1, a sub-circuit 10 incorporating a buffer 2 and a charge-pumping circuit 3 and a supply portion 4, a main circuit 20 incorporating a buffer 2' and a charge-pumping circuit 3' and a supply portion 4', and a detector 5. A set of voltage converter stages are arranged in parallel in order to be divided in operation, so that futile power consumption is reduced in the case of the provision of the quiescent supply and the stability of the internal supply source voltage is also improved. Application to semiconductor memory devices.

Apparatus employing a welding power supply for powering a plasma cutting torch

Abstract: A boosting circuit is used to boost the voltage output of a DC selding power supply to a higher voltage output adequate for powering a plasma cutting torch. The boosting circuit includes a first inductive stage including an inductor receiving energy from a DC welding power supply. The boosting circuit also includes a capacitive second stage receiving energy from the inductor in the first stage where the two stages together boost the output of the boosting circuit to a voltage output higher than that supplied by the welding power supply.

Optimal feed-forward compensation for PWM DC/DC converters

Abstract: An analytical procedure for optimizing the feedforward compensation for any PWM (pulse width modulation) DC-DC converter is described The aim of achieving zero DC audio-susceptibility was found to be possible for the buck, buck-boost, Cuk, and SEPIC cells; for the boost converter, however, only nonoptimal compensation is feasible Rules for the design of PWM controllers and procedures for the evaluation of the hardware-introduced errors are given A PWM controller implementing the optimal feedforward compensation for buck-boost, CUK, and SEPIC cells is described and experimentally characterized >

Inverse dual converter (IDC) for high power DC-DC applications

Abstract: The inverse dual converter (IDC), suitable for high-power DC-DC conversion applications, is presented. The IDC is a voltage source converter with an AC link and has been derived from an inductor converter bridge. This capacitor commutated converter is capable of continuous voltage step-up or step-down control over a wide range without the need of a transformer. In addition to high-frequency switching the converter is characterized by soft switching techniques, reducing constraints on the ratings of the switches. The average model developed with the help of gyrator theory provides sufficient information for control strategies and design considerations. The results of gyrator modeling and computer simulation are compared with experimental results obtained from a prototype IDC. >

Qualitative analysis and control of a DC-to-DC boost converter operating in discontinuous mode

Abstract: The boost cell operating in discontinuous conduction mode based on an approximate discrete-time difference equation is investigated. A qualitative discussion of the steady-state and open-loop dynamical behavior is presented. A linearized small-signal equation that leads to a linear feedforward control law for regulating this type of converter is derived. The conventional linear scheme provides satisfactory control in the neighborhood of the operating point, but ceases to meet the requirement as soon as the small-signal assumption is violated. A nonlinear feedforward control law whose validity extends over a wider range of fluctuation of the variables about the operating point is proposed, along with some simulation results that confirm the superiority of the proposed nonlinear control over its linear counterpart. >

High-efficiency, high-density, power supply including an input boost power supply

Abstract: A power supply includes a dc-to-dc converter with an integral boost power supply for maintaining the effective converter input voltage within a predetermined steady-state range, even if the input voltage to the power supply exhibits substantial voltage transients. In one preferred embodiment, the boost power supply comprises a boost transformer and a rectifier, and the converter comprises two parallel-coupled resonant converter modules, each including either a half-bridge or full-bridge connection of switching devices and a resonant circuit. The primary winding of the boost transformer is coupled between the junctions joining the switching devices of the resonant converter bridges. When the power supply input voltage is outside the steady-state voltage range, the boost power supply is activated by phase shift control of the voltage across the primary winding of the boost transformer.

Power supply with multiple outputs and load balancing

Abstract: A power supply with multiple outputs including at least two power converters, each with multiple outputs, a first output of a first power converter being connected in parallel with a first output of a second converter to provide a first load with current. The power supply further includes a first regulating circuit for delivering to each power converter a command signal that is a function of the current delivered to the first load. The power supply also includes at least one other regulating circuit for delivering to an output regulator (postregulator) connected between each power converter and a load other than the first load, a command signal which is a function of the current delivered by each converter output to the load other than the first load.

DC-DC converter and a computer using the converter

Abstract: In order to provide miniaturization and increased-frequency operation of a DC-DC converter used with a computer, etc., a capacitor is connected in parallel with a switching element when the switching element is turned off to reduce turn-off loss. When the switching element is turned on, the capacitor and a DC power source are connected in series to supply the energy stored in the capacitor to a load circuit to result in a high initial voltage being applied across the load circuit.

Coupled inductor type dc to dc converter with single magnetic component

Abstract: A coupled inductor type boost DC to DC converter with a single multipurpose magnetic component. The invention includes a conventional switch for converting an input DC voltage to a signal having a time varying waveform. The switch Q1 has a pole terminal connected to a source of input voltage, a control terminal and first and second throw terminals. The single inductive element includes a first winding LN1 connected between an output terminal of the switch and an input terminal of the converter and a second winding LN2 connected between the second throw terminal of the switch and an output terminal of the converter. In a first embodiment, the invention further includes a winding LN3 of the inductive element connected at a first end to the control terminal of the switch which provides a level shifting circuit for shifting the level of a drive signal applied to the control terminal of the switch.

DC/DC switching converter circuit

Abstract: A two switch, DC/DC converter provides sufficient inductive energy storage at the termination of the "on" period of each switch to alter the charge on the intrinsic and stray capacitance of the combination of switches producing zero voltage across the alternate switch prior to its turn on. A short dead-band between the turn on pulses provided by the control circuit allows time for this transition. Thus the energy stored in the capacitance of the switches is returned to the source and load rather than being dissipated in the switching devices. This greatly improves the efficiency of the converter particularly when operating at high frequency. The unique topology of the converter provides other new and useful characteristics in addition to zero voltage switching capability such as operation at constant frequency with pulse-width-modulation for regulation, quasi-square wave output current, and the ability to integrate the magnetic elements with or without coupling.

Analysis and design of LCL-type series resonant converter

Abstract: A series resonant power converter modified by adding an inductor in parallel with the transformer primary (or secondary) is presented. This configuration is referred to as 'LCL-type series resonant converter'. A simplified steady-state analysis using complex circuit analysis is presented. Based on the analysis, a simple design procedure is given. Detailed experimental results obtained from a MOSFET-based 500 W converter are presented to verify the analysis. A narrow variation in switching frequency is required to regulate the output voltage constant for a very wide change in load, and the converter has load short circuit capability. It is shown that by placing the parallel inductor on the secondary-side, the parasitics of the high-frequency transformer can be used profitably. >

Power conversion system with instantaneous real power feedback control

Abstract: A voltage PWM converter/inverter system comprises a converter for converting an alternating current power input into a direct current power output and inverting the direct current power output of the converter into an alternating current power output. A smoothing circuit is inserted between the converter and the inverter and an instantaneous real power calculating unit calculates an instantaneous real power for the inverter to provide an output comprising an instantaneous real power calculated value. The system includes a converter controller for voltage PWM control of the converter based on a set converter command value, a terminal direct current voltage value of the smoothing capacitor, and the instantaneous real power calculated value. The system further includes an inverter controller for voltage PWM control of the inverter based upon a set inverter command value and the alternating current power provided as a an output by the inverter.

Selective output disconnect for a single transformer converter

Abstract: A single transformer converter which may switchably disconnect all of its converter outputs, or alternatively just some of the converter outputs. In some electronic systems this would allow the turning-off of some units, such as printers, while leaving on other units, such as a CPU or a twenty-four hour clock. Further, an uninterruptible output is provided by the converter to maintain applications and operating systems software stored a CMOS RAM even in the event of a power outage.

Supply circuit for a multisystem locomotive

Abstract: The invention relates to a supply circuit (16) for a multi-system locomotive, the supply circuit (16) containing a first and second power converter (18, 20) which are each connected in an electrically conductive manner to a first and second inverter (6, 7) by means of a first and second intermediate circuit capacitor (10, 12). According to the invention, the AC-side terminals (22, 28) of the first bridge branches (24, 30) and the AC-side terminals (32, 38) of the second bridge branches (34, 40) of the two power converters (18, 20) are connected to one another by means of inductors (26, 36), the power converter valves (V13, V14) of the second bridge branch of the first power converter (18) and the power converter valves (V21, V22) of the first bridge branch (30) of the second power converter (20) being drivable by means of a control circuit (52) which generates control signals as a function of a DC input voltage (UE) and an intermediate circuit reference voltage (UKsoll), whereas the other power converter valves (V11, V12, V23, V24) of the two power converters (18, 20) can be driven in clocked fashion by means of a further control circuit (58). In this way, a supply circuit (16) for a multi-system locomotive is obtained with which, in the case of DC voltage supply and AC voltage supply, a controlled intermediate circuit actual voltage (UK1, UK2) is obtained.

Multiple-output, single-ended, resonant power converter

Abstract: A single-ended, resonant power converter includes an input filter having at least one primary winding and multiple auxiliary, or secondary, windings. A regulated input DC voltage is transformed directly to the auxiliary windings. The voltages across the auxiliary windings are respectively rectified and filtered to provide multiple, auxiliary, regulated output voltages which are independent of the main output voltage and converter switching frequency.