Showing papers on "Boost converter published in 1999"

A boost DC-AC converter: analysis, design, and experimentation

Abstract: This paper proposes a new voltage source inverter (VSI) referred to as a boost inverter or boost DC-AC converter. The main attribute of the new inverter topology is the fact that it generates an AC output voltage larger than the DC input one, depending on the instantaneous duty cycle. This property is not found in the classical VSI, which produces an AC output instantaneous voltage always lower than the DC input one. For the purpose of optimizing the boost inverter dynamics, while ensuring correct operation in any working condition, a sliding mode controller is proposed. The main advantage of the sliding mode control over the classical control schemes is its robustness for plant parameter variations, which leads to invariant dynamics and steady-state response in the ideal case. Operation, analysis, control strategy, and experimental results are included in this paper. The new inverter is intended to be used in uninterruptible power supply (UPS) and AC driver systems design whenever an AC voltage larger than the DC link voltage is needed, with no need of a second power conversion stage.

Multifrequency averaging of DC/DC converters

Abstract: This paper presents some of the issues involved in applying frequency-selective averaging to modeling the dynamic behavior of pulsewidth-modulated (PWM) DC-DC converters. We use the boost converter as an example to show the details involved in deriving some novel extended averaged models, and we use simulations to highlight the accuracy of the models even when traditional small-ripple conditions are not satisfied.

Performance characteristics of a cascaded two-level converter

Abstract: A cascaded two-level power converter is proposed which utilizes two six-transistor inverters and is capable of producing voltages which are identical to those of three-level and four-level converters. Since the machine voltages are the same, the converter performance is the same as is verified through laboratory tests. The advantages and disadvantages of the proposed cascaded converter are explored. The proposed converter is simpler to construct and offers more nonredundant switching states per number of active semiconductors than standard multi-level converters.

A fully digital, energy-efficient, adaptive power-supply regulator

Abstract: A voltage scaling technique for energy-efficient operation requires an adaptive power-supply regulator to significantly reduce dynamic power consumption in synchronous digital circuits. A digitally controlled power converter that dynamically tracks circuit performance with a ring oscillator and regulates the supply voltage to the minimum required to operate at a desired frequency is presented. This paper investigates the issues involved in designing a fully digital power converter and describes a design fabricated in a MOSIS 0.8-/spl mu/m process. A variable-frequency digital controller design takes advantage of the power savings available through adaptive supply-voltage scaling and demonstrates converter efficiency greater than 90% over a dynamic range of regulated voltage levels.

Hysteretic regulator and control method having switching frequency independent from output filter

Abstract: A DC to DC power converter (58) and method of controlling the DC to DC power converter (58). The converter (58) has a first switch (S 1 ) coupled to a second switch (S 2 ). The converter (58) is adapted to receive an input voltage V in , generate an output voltage V out , and operate at a switching frequency. A hysteretic mode control circuit (52) includes a first circuit generating a ramp signal at input (56) for controlling the converter (58). The first circuit includes a first capacitor (C 1 ) with the ramp signal generated at an end of the first capacitor (C 1 ). The hysteretic mode control circuit (52) is coupled to the first (S 1 ) and second (S 2 ) switches, where the switching frequency of the first and second switches is dependent upon the ramp signal (56) determined by the value of the components of the first circuit rather than on the voltage from the output filter of the DC to DC power converter. The invention is particularly useful for applications such as DSPs and mixed signal or analog circuits.

Dual-mode non-isolated corded system for transportable cordless power tools

Abstract: A dual-mode system for inexpensively operating electrically powered double-insulated devices ( 12 ), such as hand-held power tools and appliances. The system includes a cordless battery pack ( 14 ) that supplies the power and current demands of the device ( 12 ) in a cordless mode or a non-isolated corded voltage converter ( 16 ) that supplies the necessary power and current demands in a physical envelope commensurate in size and interchangeable with that of the battery pack ( 14 ). The corded voltage converter ( 16 ) is provided with a non-isolated high efficiency power supply that allows the converter ( 16 ) to generate the power and current required by the driven device ( 12 ). The double insulation of the driven device ( 12 ) negates the need for a transformer-isolated voltage converter. Eliminating the power transformer from the converter significantly reduces the cost of the module ( 16 ). Additionally, the need for multiple battery packs and fast rechargers is minimized by the availability of a low-cost converter. The voltage converter ( 16 ) includes an inrush current limiter ( 103 ) and power conditioner for filtering AC or DC input power. The filtered voltage is chopped by a transformerless buck-derived converter. The chopped voltage is rectified and filtered to provide low-voltage DC power to the drive motor of the powered double-insulated device ( 12 ).

A 'zero' ripple technique applicable to any DC converter

Abstract: Coupled magnetics filter techniques are important tools in a converter designer's arsenal, but are not well understood. Evidence of this is one basic building block of coupled filters, reinvented numerous times during the past 65 years. A detailed analysis of coupled magnetics for DC-DC converters, based on a key building block, is given.

Interleaved zero current switching in a power factor correction boost converter

Abstract: A method and apparatus for interleaving switching of multiple transistor switches in a power factor correction (PFC) boost converter and for timing the switching to occur when a current through a freewheeling diode corresponding to each switch is at a minimum level. The converter draws input current from an alternating current power supply for forming a regulated output voltage. A controller senses an input current and an output voltage across an output capacitor for controlling switching to regulate the output voltage and to ensure that the input current is substantially in phase with an input voltage. Current through a first inductor associated with a first switch is allowed to fall substantially to zero upon discharging the first inductor prior to re-charging the first inductor. Charging of a second inductor associated with a second switch, however, is initiated prior to completion of discharging the first inductor. Similarly, current through the second inductor is allowed to fall substantially to zero prior to re-charging the second inductor. An advantage is that from the perspective of the power supply, the converter operates in continuous conduction mode, while from the perspective of each of the switches, the converter operates in discontinuous conduction mode. The invention reduces power dissipated in the switches, increasing reliability and allowing higher frequency operation. In accordance with another aspect of the invention, a synchronizing signal is generated by the PFC converter for synchronizing operation of a second converter, such as a pulse-width modulation converter, with the PFC converter.

A three-switch high-voltage converter

Abstract: A novel single active switch two-diodes high-voltage converter is presented. This converter can operate into a capacitor-diode voltage multiplier, which offers simpler structure and control, higher efficiency, reduced electromagnetic interference (EMI), and size and weight savings compared with 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.

Analytical calculation of the RMS current stress on the DC link capacitor of voltage DC link PWM converter systems

Abstract: In this paper a simple analytical expression for the current stress on the DC link capacitor of a voltage DC link converter system, as caused by the load-side inverter is derived. There, a sinusoidal inverter output current and a constant value of the DC link voltage are assumed. The DC link capacitor current RMS value is determined by the modulation depth and by the amplitude and the phase angle of the inverter output current. Despite the neglection of the output current ripple the results of the analytical calculation match very well with a digital simulation even if the output current ripple is relatively high as given, e.g., for low-frequency IGBT inverter systems. Thus, the approximation can advantageously be used for designing the DC link capacitor of PWM converter systems.

Effect of voltage sags on adjustable-speed drives: a critical evaluation and an approach to improve performance

Abstract: In this paper, a critical evaluation of the effect of voltage sags on adjustable-speed drives (ASDs) is presented. In particular, the DC-link voltage variation under voltage sag and its dependence on source impedance, DC-link inductance and output load is computed. It is shown that, for larger source impedance, the DC-link voltage variation under a voltage sag is also large and increases the susceptibility of an ASD and may result in a nuisance trip. The results from the analysis are plotted in per-unit quantities and serve as a design guide to assess ASD performance for a variety of sags. In order to improve the performance of ASDs, this paper proposes an integrated boost converter approach. This approach provides ride-through to critical ASD load during voltage sags without any additional energy storage device. Upon detection of a voltage sag, the boost converter operates with suitable duty ratio and maintains the DC-link voltage within acceptable limits. This prevents nuisance tripping and facilitates continuous operation of critical ASD load at rated torque. The proposed integrated boost converter does not introduce any additional semiconductors in the series path of the power flow and is low in cost. A commercially available 480 V 22 kVA ASD is modified with the integrated boost converter approach, and details are discussed. Analysis, simulation, and experimental performance of the ride-through approach are presented.

Design and analysis of a switched-capacitor-based step-up DC/DC converter with continuous input current

Abstract: This paper presents the use of the current control scheme in switched-capacitor (SC)-based step-up dc/dc converter. It not only includes all positive characteristics of previous SC converters, including small size, light weight, high power density, and the amenability to IC hybridization, but also has the prominent features of continuous input current waveform and better regulation capability than the traditional SC converters. The problem of conducted electromagnetic interference with the supply network, which generally exists in previous SC converters, is highly suppressed. The concept of energy transfer is achieved by using dual SC step-up converter cells operating in antiphase. Each cell is switching between two topologies for the same duration. The dc voltage conversion ratio is controlled by the current control scheme in order to adjust the charging profile of the capacitors. A generalized n-stage converter is presented and is analyzed by a simplified third-order state-space equation set. The static and dynamic behaviors and the design constraints of the converter are derived. A prototype of the 30 W 5 V/12 V two-stage converter has been built, giving an overall efficiency of 78% with power density of 15 W/in/sup 3/. Its stability of operation is also presented.

Hopf bifurcation and chaos from torus breakdown in a PWM voltage-controlled DC-DC boost converter

Abstract: The behavior of a closed loop dc-dc boost converter is investigated when the pulse width modulation (PWM) period is varied. The dynamics are analyzed both by using analytical solutions of the state equations and by the stroboscopic map. This analysis shows that Hopf bifurcation occurs at a certain value of the parameters. Phase-locking periodic windows, the period adding sequence, and the transition from quasi-periodicity to period doubling via torus breakdown are also obtained. An experimental prototype was built to check the numerical results. Parasitic elements, such as the equivalent series resistance of the inductor and the conducting voltage of the diode, are included in the model to obtain better concordance with experiments.

A new, soft-switched boost converter with isolated active snubber

Abstract: A boost power converter which employs an isolated active snubber to reduce the losses caused by the reverse-recovery characteristic of the boost rectifier and the turn-on discharge loss of the output capacitance of the boost switch is described. The proposed isolated active snubber consists of a coupled inductor, clamp capacitor and ground-referenced n-type MOSFET. The performance of the proposed power converter is evaluated on a 1 kW, universal-line-range, boost input-current shaper.

High power factor rectifier with reduced conduction and commutation losses

Abstract: This paper presents a high power factor rectifier with reduced conduction and commutation losses for telecommunication applications. The reduced conduction losses are obtained through the use of a single converter, instead of the conventional configuration, composed of a four-diode front-end rectifier followed by a boost converter. A nondissipative snubber is responsible for the reduction in the commutation losses. A prototype rated at 1.6 kW, operating at 25 kHz with IGBTs has been implemented in laboratory.

Isolated and soft-switched power converter

Abstract: An isolated and soft-switched power converter is used for DC/DC and DC/DC/AC power conversion. The power converter includes two resonant tank circuits coupled back-to-back through an isolation transformer. Each resonant tank circuit includes a pair of resonant capacitors connected in series as a resonant leg, a pair of tank capacitors connected in series as a tank leg, and a pair of switching devices with anti-parallel clamping diodes coupled in series as resonant switches and clamping devices for the resonant leg. The power converter is well suited for DC/DC and DC/DC/AC power conversion applications in which high-voltage isolation, DC to DC voltage boost, bidirectional power flow, and a minimal number of conventional switching components are important design objectives. For example, the power converter is especially well suited to electric vehicle applications and load-side electric generation and storage systems, and other applications in which these objectives are important. The power converter may be used for many different applications, including electric vehicles, hybrid combustion/electric vehicles, fuel-cell powered vehicles with low-voltage starting, remote power sources utilizing low-voltage DC power sources, such as photovoltaics and others, electric power backup systems, and load-side electric storage and generation systems.

Integrated planar inductor scheme for multi-module interleaved quasi-square-wave (QSW) DC/DC converter

Abstract: Compact, high-efficiency, low-voltage and large-current DC/DC power converters with a fast transient slew rate are needed for future generation microprocessors. The interleaved quasi-square-wave (QSW) topology is a good candidate to improve their transient response significantly. Inductors are critical components in these converters. An integrated planar inductor scheme for multi-module interleaved QSW power converters is proposed. This integrated inductor utilizes the phase relationships of the currents in each module to integrate all the separate inductors for each module into one core, resulting in great reductions in the size and power losses of the inductor.

Buck converter with inductive turn ratio optimization

Abstract: A DC--DC power converter circuit for converting relatively high input voltages to relatively low output voltages employs a buck-type circuit topology with a multiple winding inductor. An optional winding is provided to the inductor to clamp a voltage spike appearing on the drain of one of the switching devices. Optionally, two inductor windings may be capacitively coupled for better efficiency.

Charge pump for operation at a wide range of power supply voltages

Abstract: In a charge pump for providing a desired boosted output voltage, a plurality of boosting stages are connected in series. The pump also has a clock signal supply circuit for providing clock signals and a boost circuit for boosting the clock signals. Clock signals derived from the clock signal supply circuit are supplied to each of the boosting stages on a former side. In contrast, a boosted clock signal derived from the clock signal boost circuit and a clock signal derived from the clock signal supply circuit are supplied to each of the boosting stages on a latter side.

Dynamic performance of PWM DC-DC boost converter with input voltage feedforward control

Abstract: Small-signal characteristics are studied for a pulse-width modulated (PWM) boost converter with input voltage feedforward control. The characteristics are valid for the continuous conduction mode (CCM). A small-signal circuit model is used to derive the input-to-output voltage transfer function (audio-susceptibility), the input impedance, and the output impedance. A response of the output voltage to a step change in the input voltage is also computed. The measured Bode plots of the input-to-output voltage transfer function agreed with that predicted theoretically. It is shown that the feedforward control may reduce the magnitude of the input-to-output voltage transfer function by 40 dB. The input resistance of the converter with feedforward control is negative at low frequencies. The output impedance is not affected by feedforward control.

A single-stage power-factor-corrected AC/DC converter

Abstract: This paper presents a single-stage isolated converter topology designed to achieve a regulated DC output voltage having no low-frequency components and a high-input power factor. The topology is derived from the basic two-switch forward converter, but incorporates an additional transformer winding, inductor and a few diodes. The proposed circuit inherently forces the input current to be discontinuous and AC modulated to achieve high-input power factor. The converter output is operated in discontinuous mode to minimize the bulk capacitor voltage variations when the output load is varied. Analysis of the converter is presented, and performance characteristics are given. Design guidelines to select critical components of the circuit are presented. Experimental results on a 150 W 50 kHz universal input (90-265 V) 54.75 V output AC/DC converter are given which confirm the predicted performance of the proposed topology.

Single stage high power-factor converter

Abstract: An output of a first converter for switching a rectified line current and an output of a second converter for switching a direct current are added together so that an efficiency, a power factor, a holding time, and a ripple characteristic can be improved. Further, the power supply apparatus can be made compact and the cost for manufacturing the apparatus can be reduced. A flyback converter type output circuit and a forward converter type output circuit are used in a parallel manner so that a transformer having a high efficiency can be used, and it becomes easier to control the apparatus.

Forward-flyback converter with current-doubler rectifier: analysis, design, and evaluation results

Abstract: Complete design-oriented steady-state analysis of the forward-flyback converter, with the current-doubler rectifier is provided. Advantages and disadvantages of this topology compared to the conventional forward converter are discussed. In particular, the transformer-secondary copper losses are evaluated. In addition, a step-by-step design procedure is given, Finally, experimental evaluation results obtained on a 3.3 V/50 A DC/DC converter prototype for the 40-60 V input-voltage range are presented.

A power line conditioner based on flying capacitor multilevel voltage source converter with phase shift SPWM

Abstract: In this paper, a new power line conditioning system is proposed. This system is constructed by a flying capacitor multilevel VSC (voltage source converter) and two reactors. The phase-shift SPWM (sinusoidal pulse width modulation) switching scheme is applied to control the switching devices of this converter. Due to this multilevel VSC and the switching scheme applied to this converter, the system is applicable to distribution systems or industrial applications. The reactive power compensation, harmonic suppression and load balancing functions of the power line conditioner are analyzed. A novel and effective startup procedure is proposed to start up the system. System simulation is carried out to verify the theoretical analysis results.

Control strategy of an interleaved boost power factor correction converter

Abstract: Power factor correction interleaved boost converters provide a reduction of the inductor volume and weight when compared with the conventional PFC boost converter. However, to achieve these benefits, proper current sharing and current ripple minimization must be ensured. This paper proposes a controller based on the Lyapunov-likelihood control technique for interleaved boost converters (IBC) that ensures output voltage regulation and proper current share for each boost cell. In addition, a switching logic scheme for the IBC is developed to guarantee the input current ripple minimization. Extensive simulations are presented to demonstrate the performance of the proposed control and switching logic scheme.

Power module for a frequency converter

Abstract: Power module for a current converter, particularly a frequency converter, having at least one printed circuit board equipped at least with power components and having a heat-conducting connection with a wall of the current converter housing serving as heat sink, the power module having electrically conducting connection parts arranged vertically to the housing wall, which parts laterally confine a chamber and are long enough to enable accommodation of large, passive electrical components, such as capacitors, in the chamber. To ensure a space saving embodiment of the power module, though maintaining a sufficient heat dissipation and simplifying the electrical connection between the power module and the remaining components of the converter, it is provided that the only electrical connection between the power module and other electrical components of the converter as well as to the supply mains and to a load supplied via the converter is established via the connection parts.

DC-to-DC converter capable of preventing overvoltage

Abstract: To avoid burning out a capacitor in a synchronous rectification type DC-to-DC converter due to overvoltages, the synchronous rectification type DC-to-DC converter includes a storage unit storing therein power derived from a power supply, switching elements connecting and disconnecting respective signal paths from power and ground, and a control unit controlling the connecting/disconnecting operations of the switching elements to maintain a voltage output from the storage unit at a predetermined value. The DC/DC converter also includes an overvoltage detecting unit monitoring a voltage derived from the power supply to thereby output an alarm signal when the voltage derived from the power supply exceeds a preselected voltage value, a shortcircuiting unit influencing the connecting conditions of the switching elements when the alarm signal from the overvoltage detecting unit is input therein, whereby the voltage derived from the power supply is shortcircuited, and an interrupting unit interrupting one of the signal paths by the power shortcircuited by the shortcircuiting unit.

Calculation of the periodic spectral components in a chaotic DC-DC converter

Abstract: A simple mapping is derived, which describes the behavior of a peak current-mode controlled boost converter operating chaotically. The invariant density of this mapping is calculated iteratively and, from this, the power density spectrum of the input current at the clock frequency and its harmonics are deduced. The calculation is presented, along with experimental verification. The possibility of a novel application of chaos-amelioration of power supply interference-is discussed,.

Output ripple analysis of multiphase DC-DC converters

Abstract: This paper presents an output ripple analysis of multiphase DC-DC power converters having an output LC filter. Analytical expressions for the output voltage ripple of two- and three-phase DC-DC power converters are derived. Influence of the coupling coefficient of the output filter inductor on the output ripple is investigated. Because the unique parameters of the LC filter cannot be determined solely based on the specified maximum output ripple, an additional criterion based on minimum energy storage is introduced. A comparative evaluation of single-phase, two-phase, and three-phase DC-DC power converters is presented. The validity of the proposed analysis method is verified by experimental results.

Analysis and design of three-phase AC-to-DC converters with high power factor and near-optimum feedforward

Abstract: This paper presents a three-phase pulsewidth modulated AC-to-DC power converter with unity power factor and near-optimum dynamic regulation. A general mathematical model of the converter has been established to lead to a comprehensive analysis. The averaged small-signal technique is used to obtain the near-optimum feedforward compensator, thus resulting in the output impedance, and the audio susceptibility become zero, that is, the output voltage of the converter presented in this paper is independent of variations of the DC load current and the utility voltage. The proposed procedure of analysis is simple and effective, and it is also easy to implement. Finally, the theoretical formulations are verified both by simulated and experimental results in a 5 kW laboratory prototype system.