Showing papers on "Flyback converter published in 2003"

Voltage converter control apparatus, voltage conversion method, storage medium, program, drive system, and vehicle having the drive system

Abstract: By using a target voltage Vc* of a capacitor connected to the output side of a DC/DC converter and a voltage Vb of a battery connected to the input side of the DC/DC converter, a duty ratio D (Vb/Vc*) as a drive instruction of the DC/DC converter is calculated (S100, S102). By using the voltage Vb, the electromotive force Vbo of the battery, and the charge/discharge current Ib of the battery, an internal resistance Rb ((Vbo - Vb)/Ib) is calculated (S104). According to the internal resistance Rb and the electromotive force Vbo, the current value (value Vbo/2Rb) when the battery output becomes maximum is set as the upper limit value of the optimal current range IR (S106). the DC/DC converter is driven/controlled by limiting the duty ratio D so that the current Ib is within the range of the optimal current range IR (S108, S110, S112). Thus, it is possible to appropriately convert the battery input voltage.

DC bus voltage control for a distributed power system

Abstract: This paper addresses voltage control of distributed DC power systems. DC power systems have been discussed as a result of the introduction of renewable, small-scale power generation units. Also, telecommunication power systems featuring UPS properties might benefit from a broader introduction of DC power systems. Droop control is utilized to distribute the load between the source converters. In order to make the loading of the source converters equal, in per unit, the voltage control algorithm for each converter has to be designed to act similar. The DC side capacitor of each converter, needed for filtering, is also determined as a consequence. The root locus is investigated for varying DC bus impedance. It is found that the risk of entering converter over-modulation is a stronger limitation than stability, at least for reasonable DC bus cable parameters. The stationary and dynamic properties during load variations are also investigated.

Single-inductor multiple-output switching converters with time-multiplexing control in discontinuous conduction mode

Abstract: An integrated single-inductor dual-output boost converter is presented. This converter adopts time-multiplexing control in providing two independent supply voltages (3.0 and 3.6 V) using only one 1-/spl mu/H off-chip inductor and a single control loop. This converter is analyzed and compared with existing counterparts in the aspects of integration, architecture, control scheme, and system stability. Implementation of the power stage, the controller, and the peripheral functional blocks is discussed. The design was fabricated with a standard 0.5-/spl mu/m CMOS n-well process. At an oscillator frequency of 1 MHz, the power conversion efficiency reaches 88.4% at a total output power of 350 mW. This topology can be extended to have multiple outputs and can be applied to buck, flyback, and other kinds of converters.

Multi-mode renewable power converter system

Abstract: A multi-mode renewable power converter system is disclosed. The system includes a control unit, a boost converter, an inverter and optional bi-directional charger, wherein the boost converter converts DC output of a solar cell or a renewable source to high DC bus voltage, and the inverter converts this DC bus voltage to an AC output. This power converter can be used to support standalone load or grid-connected system with a dynamic maximum power point tracking (MPPT) circuit. The MPPT circuit detects the current and voltage from the solar cell and indicates to the inverter to provide power to the load connected. When the optional bi-directional charger is installed, the MPPT signal is also fed to this charger to make the power efficiency maximized for the system.

Advanced DC/DC Converters

Abstract: INTRODUCTION Historical Review Multiple Quadrant Choppers Pump Circuits Development of DC/DC Conversion Technique Categorize Prototypes and DC/DC Converters Family Tree VOLTAGE-LIFT CONVERTERS Introduction Seven Self-Lift Converters Positive Output Luo-Converters Negative Output Luo-Converters Modified Positive Output Luo-Converters Double Output Luo-Converters POSITIVE OUTPUT SUPER-LIFT LUO-CONVERTERS Introduction Main Series Additional Series Enhanced Series Re-Enhanced Series Multiple-Enhanced Series Summary of Positive Output Super-Lift Luo-Converters Simulation Results Experimental Results NEGATIVE OUTPUT SUPER-LIFT LUO-CONVERTERS Introduction Main Series Additional Series Enhanced Series Re-Enhanced Series Multiple-Enhanced Series Summary of Negative Output Super-Lift Luo-Converters Simulation Results Experimental Results POSITIVE OUTPUT CASCADE BOOST CONVERTERS Introduction Main Series Additional Series Double Series Triple Series Multiple Series Summary of Positive Output Cascade Boost Converters Simulation and Experimental Results NEGATIVE OUTPUT CASCADE BOOST CONVERTERS Introduction Main Series Additional Series Double Series Triple Series Multiple Series Summary of Negative Output Cascade Boost Converters Simulation and Experimental results MULTIPLE-QUADRANT OPERATION LUO-CONVERTERS Introduction Circuit Explanation Mode A (Quadrant I Operation) Mode B (Quadrant II Operation) Mode C (Quadrant III Operation) Mode D (Quadrant IV Operation) Simulation Results Experimental Results Discussion SWITCHED-COMPONENT CONVERTERS Introduction A Two-Quadrant SC DC/DC Converter Four-Quadrant Switched Capacitor DC/DC Converter Switched Inductor Four-Quadrant DC/DC Converter POSITIVE OUTPUT MULTIPLE-LIFT PUSH-PULL SWITCHED-CAPACITOR CONVERTERS Introduction Main Series Additional Series Enhanced Series Re-enhanced Series Multiple-Enhanced Series Theoretical Analysis Summary of this Technique Simulation Results Experimental Results NEGATIVE OUTPUT MULTIPLE-LIFT PUSH-PULL SWITCHED-CAPACITOR CONVERTERS Introduction Main Series Additional Series Enhanced Series Re-Enhanced Series Multiple-Enhanced Series Summary of this Technique Simulation and Experimental Results MULTIPLE-QUADRANT SOFT-SWITCHING CONVERTERS Introduction Multiple-Quadrant DC/DC ZCS Quasi-Resonant Converters Multiple-Quadrant DC/DC ZVS Quasi-Resonant Converter Multiple-Quadrant Zero-Transition DC/DC Converters SYNCHRONOUS RECTIFIER DC/DC CONVERTERS Introduction Flat Transformer Synchronous Rectifier Converter Active Clamped Synchronous Rectifier Converter Double Current Synchronous Rectifier Converter Zero-Current-Switching Synchronous Rectifier Converter Zero-Voltage-Switching Synchronous Rectifier Converter MULTIPLE ENERGY-STORAGE ELEMENTS RESONANT POWER CONVERTERS Introduction Bipolar Current and Voltage Source A 2-Element RPC Analysis P-CLL CURRENT SOURCE RESONANT INVERTER Introduction Mathematic Analysis Simulation Results Discussion CASCADE DOUBLE G-CL CURRENT SOURCE RESONANT INVERTER Introduction Mathematic Analysis Simulation Results Experimental Results Discussion CASCADE REVERSE DOUBLE G-LC RESONANT POWER CONVERTER Introduction Steady-State Analysis of Cascade Reverse Double G-LC RPC Resonance Operation and Modeling Small-Signal Modeling of Cascade Reverse Double G-LC RPC Discussion DC ENERGY SOURCES FOR DC/DC CONVERTERS Introduction Single-Phase Half-Wave Diode Rectifier Single-Phase Bridge Diode Rectifier Three-Phase Half-Bridge Diode Rectifier Three-Phase Full-Bridge Diode Rectifier with Resistive Load Thyrister Rectifiers CONTROL CIRCUIT. EMI AND APPLICATIONS EXAMPLES OF DC/DC CONVERTERS Introduction Luo-Resonator EMI, EMS and EMC Some DC/DC Converter Applications

An interleaved boost DC-DC converter with large conversion ratio

Abstract: A new PWM dc-dc converter is introduced in which large voltage step-up ratios can be achieved without high duty-cycle, with low voltage and current stress and without transformer. The proposed circuit is an extension of the boost interleaved converter, incorporating a multistage capacitor multiplier. A simple nondissipative snubber can be used reducing the reverse recovery current of the diodes and also obtaining low turn-on and turn-off losses. The modularity of the structure allows the increment of the current, voltage and power levels, using the same range of components and maintaining high efficiency, only increasing the number of series and parallel stages. The paper gives a theoretical analysis, and experimental data on a 400 W example that was built and tested: 24 Vdc input, 200 Vdc output, and 40 kHz switching frequency. The measured performance agreed well with the theoretical predictions and the measured efficiency obtained is equal to 95% at full load.

DC Bus Voltage Control for a Distributed Power System

Abstract: This paper addresses voltage control of distributed dc power systems. DC power systems have been discussed as a re- sult of the introduction of renewable, small-scale power generation units. Also, telecommunication power systems featuring UPS prop- erties might benefit from a broader introduction of dc power sys- tems. Droop control is utilized to distribute the load between the source converters. In order to make the loading of the source con- verters equal, in per unit, the voltage control algorithm for each converter has to be designed to act similar. The dc side capac- itor of each converter, needed for filtering, is also determined as a consequence. The root locus is investigated for varying dc bus impedance. It is found that the risk of entering converter over-mod- ulation is a stronger limitation than stability, at least for reasonable dc bus cable parameters. The stationary and dynamic properties during load variations are also investigated. The paper starts with an overview of the simulation model. Then the dc bus voltage controller utilized in the analysis is introduced. The simulation model parameters are given and the controller parameters are discussed. The root locus dependency

A new AC/AC-multilevel converter family applied to a single-phase converter

Abstract: A new AC/AC-modular-multilevel converter (M/sup 2/LC) family will be introduced The new concept stands out due to its modularity as well as its extremely good control characteristics The stringent modularity results in a very cost-efficient and versatile converter construction This new M/sup 2/LC concept is well suitable for a wide range of multiphase AC/AC-converters The basic working principle together with the static and dynamic behaviour are explained in detail on a single-phase AC/AC-converter that enables four-quadrant operation It is shown that this converter concept is advantageous for future AC-fed traction vehicles and that it fulfils very well their requirements

Primary-side controlled flyback power converter

Abstract: The present invention provides a primary-side flyback power converter that supplies a constant voltage output and a constant current output. To generate a well-regulated output voltage under varying load conditions, a PWM controller is included in the power converter in order to generate a PWM signal controlling a switching transistor in response to a flyback voltage sampled from a first primary winding of the power supply transformer. Several improvements are included in this present invention to overcome the disadvantages of prior-art flyback power converters. Firstly, the flyback energy of the first primary winding is used as a DC power source for the PWM controller in order to reduce power consumption. A double sample amplifier samples the flyback voltage just before the transformer current drops to zero. Moreover, an offset current is pulled from a detection input of the double sample amplifier in order to generate a more accurate DC output voltage. The offset current is generated in response to the temperature in order to compensate for temperature-induced voltage fluctuations across the output rectifier. Ultimately, in order to maintain a constant output current, the PWM controller modulates the switching frequency in response to the output voltage.

Monopolar DC to bipolar DC to AC converter

Abstract: This invention improves the performance and lowers the cost of DC to AC inverters and the systems where these inverters are used. The performance enhancements are most valuable in renewable and distributed energy applications where high power conversion efficiencies are critical. The invention allows a variety of DC sources to provide power thru the inverter to the utility grid without a transformer and at very high power conversion efficiencies. The enabling technology is a novel inverter circuit topology where the DC source is connected directly to the positive bus of the DC to AC converter and where a negative bus is generated from the positive bus with a flyback converter. The inverter power topology does include or require a transformer. The AC inverter output configuration can be either single-phase or three-phase. The AC inverter output can be either utility interactive or directly supply loads.

Common duty ratio control of input series connected modular DC-DC converters with active input voltage and load current sharing

Abstract: In this paper, active input voltage and load current sharing of DC-DC converter modules connected in series at the input and parallel at the output employing a novel common duty ratio control concept, is proposed. An appropriate analysis and experimental results are presented to verify the proposed concepts.

Dc to ac inverter with single-switch bipolar boost circuit

Abstract: This invention improves the performance and lowers the cost of DC to AC inverters and the systems where these inverters are used. The performance enhancements are most valuable in renewable and distributed energy applications where high power conversion efficiencies are critical. The invention allows a variety of DC sources to provide power thru the inverter to the utility grid or directly to loads without a transformer and at very high power conversion efficiencies. The enabling technology is a novel boost converter stage that regulates the voltage for a following DC to AC converter stage and uses a single semiconductor switching device. The AC inverter output configuration is either single-phase or three-phase.

Voltage converter control apparatus, and method

Abstract: By using a target voltage Vc* of a capacitor connected to the output side of a DC/DC converter and a voltage Vb of a battery connected to the input side of the DC/DC converter, a duty ratio D as a drive instruction of the DC/DC converter is calculated. By using the voltage Vb, the electromotive force Vbo of the battery, and the charge/discharge current Ib of the battery, an internal resistance Rb is calculated. According to the internal resistance Rb and the electromotive force Vbo, the current value when the battery output becomes maximum is set as the upper limit value of the optimal current range IR, the DC/DC converter is driven/controlled by limiting the duty ratio D so that the current Ib is within the range of the optimal current range IR. Thus, it is possible to appropriately convert the battery input voltage.

Automotive application of multi-phase coupled-inductor DC-DC converter

Abstract: A set of four coupled inductors is applied to a four-phase interleaved 1 kW bi-directional 14 V to 42 V DC/DC converter for automotive applications. The coupled-inductor structure is optimized, and the performance is examined through simulations and experimental measurements. Although coupled inductors offer bigger advantages in applications that require fast transient response, they also have significant advantages in this type of application.

Double-input PWM DC/DC converter for high/low voltage sources

Abstract: A novel double-input PWM DC/DC converter for high/low voltage sources is proposed in this paper With PWM control, the proposed converter can draw power from two different voltage sources simultaneously or individually The operation modes and the steady-state analysis of the proposed double-input DC/DC converter are introduced in detail The control scheme for the power flow balancing is also presented By using a single passive lossless soft-switching cell, switching losses of all power switches can be reduced significantly Finally, experimental measurements are demonstrated to verify the feasibility of the proposed converter

Transformerless DC-DC converters with a very high DC line-to-load voltage ratio

Abstract: By splitting the output capacitor of a basic boost converter, and combining the resulting capacitors with the main switch in the form of a switched-capacitor circuit, a new step-up structure is realized. Without using a transformer, a high line-to-load DC voltage ratio is obtained. An output filter is added as usual in boost converters for getting a free-ripple output. The circuit compares favorably with a quadratic boost converter as regarding the count of devices and efficiency, even if it presents a lower DC gain. A DC analysis of the novel converter is presented. Experimental and simulation results confirm the theoretical expectations. By increasing the number of capacitors in the switched-capacitor circuit, higher gains are obtained. Versatility, high voltage gain and a good transient response are the features of the proposed converter.

A pwm plus phase-shift control bidirectional dc/dc converter

Abstract: A PWM plus phase-shift control bidirectional DC/DC converter is proposed. In this converter, PWM control and phase-shift control are combined to reduce current stress and both conducting and switching loss, to expand ZVS range. The operation principle and analysis of the converter are explained, and ZVS condition is derived. A prototype of PWM plus phase-shift bidirectional DC/DC converter is built to verify analysis.

Generalized structure of bi-directional switched-capacitor DC/DC converters

Abstract: This paper presents a generalized circuit structure of bi-directional switched-capacitor dc/dc converters that feature voltage step-down, voltage step-up, and bi-directional power flow. The starting point is the derivation of two structures of single-capacitor bi-directional converter cells. Current control scheme is applied in the capacitor-charging phase, resulting in a near-constant capacitor charging current and low electromagnetic interference. A converter string is then formulated by cascading a number of converter cells, in order to meet the input and output voltage requirements and conversion efficiency. By paralleling two similar strings and operating them in the anti phase, the overall converter input current becomes continuous. A reduced-order modeling and state-space averaging technique are used to study the static and dynamic behavior of the converter. The theoretical conversion efficiency in the step-down and step-up mode, respectively, is investigated for different voltage-conversion ratios and numbers of stages. The performance of the proposed structure is experimentally verified on a 5-V/12-V prototype.

Extended fundamental frequency analysis of the LCC resonant converter

Abstract: Fundamental frequency techniques are used to analyze the series-parallel resonant converter under heavy load conditions, both with a continuous, but distorted parallel capacitor voltage waveform, and with a discontinuous capacitor voltage waveform. The analysis is validated with results from an experimental prototype. The application of the technique to the parallel-loaded L-C resonant converter is also considered.

Power converter controller having event generator for detection of events and generation of digital error

Abstract: A power converter comprises an event detection module detecting various events of the power converter in real time at the switching frequency of a switch in the power converter according to predetermined criteria. A pulse generator generates control signals for controlling the on-times and off-times of the switch based on the various detected events. The events detected by the event detection module include a detection of a “knee” in the reflected secondary voltage on the auxiliary windings of the transformer in a primary side sensing flyback power converter, and detection of a digital error quantifying the difference between the reference voltage and the reflected secondary voltage on the auxiliary windings of the transformer in time domain.

AC / DC flyback converter

Abstract: A single-stage input-current-shaping (S2ICS) flyback converter achieves substantially reduced conduction losses in the primary side of the S2ICS flyback converter by connecting a bypass diode between the positive terminal of a full-bridge rectifier and the positive terminal of an energy-storage capacitor. An effective current interleaving between an energy-storage inductor and the bypass diode is thus obtained in the S2ICS flyback converter around the peak of the rectified line voltage, resulting in a significantly reduced input-current ripple and reduced current stress on the switch. Further, by rearranging the rectifiers in the ICS part of the S2ICS flyback converter in such a way that the energy-storage capacitor and the ICS inductor are connected to the ac line voltage through only two rectifiers, one diode forward-voltage drop is eliminated, which results in a substantially reduced conduction loss in the primary-side rectifiers.

Controller for DC to DC converter

Abstract: A controller (200) for a DC-to-DC converter is configured to provide a PWM signal in a first state during a first time interval based on an input voltage less a voltage level representative of an output voltage of the DC-to-DC converter The controller (200) may provide the PWM signal in the first state based on the time it takes to charge an energy storage element (202) of the controller (200) to a predetermined level The controller (200) may also provide an estimator of a zero inductor current level in an associated inductor when the energy storage element (202) is completely discharged The controller may also be a digital controller (200) that counts time pulse to provide the PWM signal A DC-to-DC converter including such a controller (200) and associated methods are also provided

High-power galvanically isolated DC/DC converter topology for future automobiles

Abstract: This paper presents a 2 kW three-phase dual active bridge converter (DAB3) which converts power between 42 V and 300 V and is easily scalable up to 20 kW. The DAB3 has been selected for this application based on detailed simulations comparing different suitable topologies. The circuits investigated in this paper can operate in a soft-switching manner enabling a reduction in device switching losses and therewith an increase in switching frequency. Candidate topologies under investigation are the serial resonant converter (SR), the single-phase dual active bridge (DAB1) and the three phase dual active bridge (DAB3). Key-features are the galvanic isolation, reduced cooling costs, and the capability of transferring energy over a wide voltage range.

A three-phase AC/AC high-frequency link matrix converter for VSCF applications

Abstract: In this paper, a new three-phase high-frequency link matrix converter is discussed and the topology of conventional matrix converter is modified with the addition of a transformer for a variable speed constant frequency (VSCF) application. The proposed approach accomplishes voltage transfer ratio more than unity, galvanic isolation between both voltage sources and higher power density by employing a high-frequency transformer into the intermediate stage of the dual bridge matrix converter. It has a bidirectional power flow capability, controllable displacement power factor and lower harmonic distortion at both variable speed source and fixed frequency utility. Further, asynchronous or synchronous PWM can be employed depending on the frequency modulation ratio in the primary side converter and it guarantees full input voltage utilization for DC-link and near symmetric square wave pulse trains applied to high frequency transformer regardless of varying input frequency. The proposed approach is a competitive solution for VSCF distributed generating application such as wind-turbine and micro-turbine application. Simulation results are shown to demonstrate the advantages of the proposed system. Experimental results on a 230V, 3kVA 400 Hz to 60 Hz VSCF system based on DSP controller are presented.

PCB integrated inductors for low power DC/DC converter

Abstract: This paper discusses the use of printed circuit board (PCB) integrated inductors for low power DC/DC buck converters. Coreless, magnetic plates and closed core structures are compared in terms of achievable inductance, power handling and efficiency in a footprint of 10 /spl times/ 10 mm/sup 2/. The magnetic layers consist of electroplated NiFe, so that the process is fully compatible with standard PCB process. Analytic and finite element method (FEM) methods are applied to predict inductor performance for typical current waveforms encountered in a buck converter. Conventional magnetic design procedures are applied to define optimum winding and core structures for typical inductor specifications. A 4.7 /spl mu/H PCB integrated inductor with dc current handling of up to 500 mA is presented. This inductor is employed in a 1.5 W buck converter using a commercial control integrated circuit (IC). The footprint of the entire converter measures 10 /spl times/ 10 mm/sup 2/ and is built on top of the integrated inductor to demonstrate the concept of integrated passives in power electronic circuits to achieve ultra flat and compact converter solutions.

Flyback power converter having a constant voltage and a constant current output under primary-side PWM control

Abstract: A primary-side flyback power converter supplies a constant voltage and a constant current output. To generate a well-regulated output voltage under varying load conditions, the power converter includes a PWM controller. The PWM controller generates a PWM signal to control a switching transistor in response to a flyback voltage detected from the first primary winding of the power supply transformer. To reduce power consumption, the flyback energy of the first primary winding is used as a DC power source for the PWM controller. The flyback voltage is sampled following a delay time to reduce interference from the inductance leakage of the transformer. To generate a more accurate DC output voltage, a bias current is pulled from the detection input to form a voltage drop across a detection resistor for compensating for the voltage drop of the output rectifying diode.

A PWM plus phase-shift control bidirectional DC-DC converter

Abstract: A PWM plus phase-shift control bidirectional DC-DC converter is proposed. In this converter, PWM control and phase-shift control are combined to reduce current stress and conducting loss, and to expand ZVS range. The operation principle and analysis of the converter are explained, and ZVS condition is derived. A prototype of PWM plus phase-shift bidirectional DC-DC converter is built to verify analysis.

Series interleaved boost converter power factor correcting power supply

Abstract: A power factor correcting power supply includes an input stage power converter and an output stage power converter. The input stage power converter includes a plurality of series connected boost switches and a power factor correction controller. The power factor correction controller may direct the operation of the boost switches with series interleave phasing to perform power factor correction and voltage regulation. The boost switches are supplied input voltage and input current from a power source. The input voltage is converted to a DC boost voltage by high frequency series interleaved switching of the boost switches. The DC boost voltage is converted to a DC output voltage by the output stage power converter. The DC output voltage is provided on a DC rail for a load of the power factor correcting power supply.

A three-level DC-DC converter with wide-input voltage operations for ship-electric-power-distribution systems

Abstract: This paper describes a newly developed three-level dc-dc converter with wide-input voltage operations for ship-electric-power-distribution systems. The proposed converter is designed with zero-voltage-switching (ZVS) techniques. The operational principles, design details and performances of the converter are discussed along with soft-switching characteristics through experimental results. Furthermore, design criteria on the dc-dc converter are focused on the minimization of the circulation current between main switches and a transformer under soft switching. The converter has achieved about 95% efficiency over wide 7-kW load conditions.