Abstract: A procedure for designing AC power line EMI filters is presented. This procedure is based on the analysis of conducted EMI problems and the use of a noise separator. Design examples are given, and results are experimentally verified.

Abstract: The method of the invention in one aspect involves electronic power control by varying the amplitude of an electrical power supply voltage, independent of frequency, whereby the output frequency will always be the same as the input frequency. An electrical circuit apparatus for accomplishing this function in a preferred embodiment is also disclosed herein. The preferred circuitry of this aspect of the invention uses four solid state switches, such as IGBT's, four diodes, an inductor, input and output filters and novel controlling circuitry. The controller apparatus and methods of the invention may be used to implement all otherwise conventional converter types, buck, boost, and inverting (and duals of these) versions to obtain different regulating characteristics, including galvanic isolation of the output from the input. The inventive methods and devices may be used in power factor correction, voltage and/or current harmonic filtering and neutralization, line and load conditioning, control of power transfer between two power grids, and programmable control of surges, sags, dropouts and most other voltage regulation problems.

Abstract: A dynamic process for reaching the maximum power point of a variable power source such as a solar cell is introduced. The process tracks maximum power nearly cycle-by-cycle during transients. Information from the natural switching ripple instead of external perturbation is used to support the maximizing process. The method is globally stable for DC-DC power converters, provided that a switching action is present. A prototype boost power converter that uses this method for control can follow power transients on time scales of a few milliseconds. This performance can be achieved with a simple analog control structure, which supports power processing with minimum loss.

Abstract: This paper presents a practical method for predicting the core losses in magnetic components for an arbitrary shape of the magnetizing current. This theory is based on a weighted time derivative of the magnetic flux density and offers the possibility to use the suppliers data, normally derived from measurements with sinewave currents, also for the real current shapes occurring in switch mode power supplies. By means of a special full-bridge power converter, a test setup is developed that allows the verification of the equations derived in this paper.

Abstract: Novel nonlinear-carrier (NLC) controllers are proposed for high-power-factor boost rectifiers. In the NLC controllers, the switch duty ratio is determined by comparing a signal derived from the main switch current with a periodic, nonlinear carrier waveform. As a result, the average input current follows the input line voltage. The technique is suitable for boost converters operating in the continuous conduction mode. Input voltage sensing, the error amplifier in the current-shaping loop, and the multiplier/divider circuitry in the voltage feedback loop are eliminated. The current-shaping is based on switch (as opposed to inductor) current sensing. The NLC controllers offer comparable or improved performance over existing schemes, and are well suited for simple integrated-circuit implementation. Experimental verification on a 240 W rectifier is described.

Abstract: By reducing the power supply voltage, a higher speed, lower power consumption, and higher integration density of data processing ICs can be achieved. Presently, a variety of ICs operating from 3.3 V are available. Next generations of ICs are expected to work even with lower voltages, i.e., in the 1-3 V range, to further enhance their speed-power performance. At the same time, during transients, these new generations of data ICs will present very dynamic loads with high current slew rates. As a result, they will require point-of-load power supplies in order to minimize the effects of the interconnection parasitics. These onboard power supplies will be derived from the existing voltages available in the system (usually 5 or 12 V), and will be required to have high power densities, high efficiencies, and good transient performance. This paper presents design considerations for these on-board power supplies and discusses their performance limits imposed by various circuit and system parasitics.

Abstract: A power supply line is wired in a loop from a battery power supply, and a power supply relay circuit is installed intermediately of the power supply line such that power is supplied from the power supply relay circuit to an electric load connected to a terminal unit of an intensive wiring line. By this arrangement, not only wires for control signals but also wires for power supply can be reduced. The terminal unit may serve also as the power supply relay circuit.

Abstract: This paper presents a digital power supply controller for variable frequency and voltage circuits. By using a ring oscillator as a method of predicting circuit performance, the regulated voltage is set to the minimum required to operate at a reference frequency which maximizes energy efficiency. Our initial test silicon, implemented with a fixed frequency controller is analyzed and reveals that the controller's power consumption is a major limitation for such a design. To make the controller power dissipation scale with the CV/sup 2/f power of the load, we introduce a new architecture with variable frequency control, which allows the controller's supply and frequency to scale along with the load device.

Abstract: A voltage control apparatus which is robust against disturbances such as variations in solar radiation amount around a solar cell, and has quick response, has a voltage detection unit (4) for detecting the voltage value of a battery power supply (1), a power conversion unit (2) for performing predetermined conversion of electric power supplied from the battery power supply, and supplying the converted electric power to a load or a commercial AC system (3), an output setting unit (5) for setting the output value of the power conversion unit on the basis of the voltage detection value, and a control unit (6) for controlling the power conversion unit on the basis of the output setting value. The output setting unit is constituted by a target voltage setting unit (51) for setting the target voltage value of the battery power supply, and an output calculation unit (52) for calculating the output setting value on the basis of the deviation between the voltage detection value and the target voltage value.

Abstract: A comprehensive and accurate steady-state analysis of a step-up DC-DC switched-capacitor power converter is performed. No approximations, such as average techniques, are invoked. Parasitic elements such as diode forward voltages, on-resistances of transistors and equivalent-series resistances of capacitors are included into the model. The converter performance functions, i.e. DC voltage ratio, efficiency, output voltage ripple, are expressed in terms of the number of switched-capacitor stages, number of capacitors per stage, values of the capacitors and parasitic elements, switching frequency and load. Design criteria aiming at high efficiency, low ripple and achievable output voltage are formulated. Trade-offs between the efficiency requirement and good regulation capability are discussed.

Abstract: The authors demonstrate the feasibility of using chaos to depress the spectral peaks of the interference from a switched mode power supply. A boost converter is used to show experimentally that the spectrum of the input current is spread, its peaks are reduced and EMC is improved, compared to the case when the circuit is operating periodically.

Abstract: In high power factor AC-to-DC applications, boost power converters operating on the boundary of continuous mode and discontinuous mode switch with variable frequency and draw high peak input currents. A method is presented to parallel two or more of these power converters to reduce the high peak input currents. Each power converter continues to operate on the boundary of continuous mode and discontinuous mode and maintains the benefits of zero-voltage switching.

Abstract: This paper compares two current-fed push-pull DC-DC power converters: the current-fed push-pull power converter or isolated boost and an alternative topology named here as the dual inductor push-pull power converter (DIC). Since this latter converter has just one primary winding, the voltage across the main switches is reduced to the half of that in the isolated boost topology; the average current in the input inductors is also halved and the RMS current in the output capacitor is smaller. The overall efficiency is increased and the power converter's volume is reduced in the DIC converter. These and other improved design characteristics make this alternative topology more attractive than the isolated boost for equivalent applications. Analytical equations, output characteristic curves and computer simulations of both power converters are compared. An experimental breadboard of 480 W power has been assembled in order to verify the performance of the DIC power converter. The main results are provided.

Abstract: A power supply is disclosed for use in battery powered electronic devices. The power supply includes a power source which supplies power to the electronic device itself as well as to battery charging circuitry integral to the power supply. The battery charging circuitry monitors an output current, or other parameter, of the power source output. Feedback circuitry regulates the output of the battery charging circuitry so that output current, or other parameter of the power source output, is kept within predetermined limits.

Abstract: An electrical signal supply apparatus independently controls and regulates voltage and current in supplying microampere currents to skin tissue of patients. The apparatus enables operators to select a desired voltage level independent of the requirement to maintain current through the skin tissue at a relatively constant level. The apparatus includes a switching regulator in combination with an electric voltage doubling network and potential divider network to enable the supply of increased voltages.

Abstract: The disclosed dual energy baggage scanning assembly includes a CT scanning system, and a conveyor belt for transporting items through the CT scanning system, and an improved power supply for the X-ray source of the CT scanner so that a dual energy beam is provided. The power supply alternately powers the X-ray tube of the scanning system at high and low voltage levels at a predetermined rate and comprises at least one high voltage DC power supply for providing a stable, high DC voltage the X-ray tube; means, including at least one waveform generator, for providing a periodic time varying waveform; and coupling means, including a transformer, for coupling the waveform generator to said DC voltage supply so that the total voltage across the cathode and anode of the tube is periodically changed between the high and low voltage levels at the predetermined rate in response to the periodic time varying waveform provided by the waveform generator.

Abstract: A power factor correction circuit includes a boost converter, a zero-current detector for detecting a period in which an inductor current is zero, a half-wave rectifier for supplying a power voltage proportional to an output voltage of the boost converter, a control voltage generator for generating a control voltage to control the turn-on time timing of a sense-FET, a turn-on controller for making constant a turn-on duration of the sense-FET, an over current detector for generating a signal when a mirror terminal current of the sense-FET is greater than a predetermined current, an OR gate for performing a logic OR operation of the output signals of the turn-on controller and the over current detector, an output current controller for generating a gate drive signal of the sense-FET, and an under voltage lock out for turning off the power voltage when the power voltage is less than a predetermined voltage. This circuit enables an external pin count to be reduced by having a built-in boost converter controller and a built-in sense-FET in a single package.

Abstract: This paper describes an adaptive digital controller for a unity power factor AC-DC power converter. The controller is based on a linear large-signal model of the boost power converter. A hardware design is presented and analyzed, followed by the software implementation of the control algorithm. Issues in digital control of power converters, such as quantization effects and fixed-point representation of system parameters, are examined in the context of this system. Experimental results are presented and compared with simulations.

Abstract: A cellular communication system which eliminates high costs and difficulties associated with providing electrical power to the access points. The cellular communication system includes a remote power source which obviates the need to install an AC power outlet in close proximity to each access point. The remote power source transforms AC power to DC power at a central remote location, and provides as its output one or more low voltage DC power lines. By performing the AC/DC power transformation at a central location, only the low voltage DC power lines need to be fed to each access point. The remote power source also includes a backup power supply feature and an alarm to draw attention to system malfunctions.

Abstract: An integrated circuit controller for power factor correction circuit that provides unity power factor by sensing only a current in the power factor correction circuit and a dc supply voltage. The power factor correction circuit is coupled to a circuit for generating the dc supply voltage. Thus, the dc supply voltage is representative of the regulated output voltage of the power factor correction circuit. The dc supply voltage is sensed and integrated over each clock cycle and compared to an inverted and amplified version of the sensed current for controlling operation of the power factor correction circuit. By sensing the dc supply voltage, rather than the output voltage of the power factor correction circuit, the integrated circuit requires fewer pins. In a preferred embodiment, the integrated circuit also includes a pulse width modulation controller circuit. Because a single clock signal is utilized for performing both leading edge modulation in the power factor correction circuit and trailing edge modulation in the pulse width modulation circuit, fewer pins are required. Therefore, the integrated circuit controls the power factor correction circuit and the pulse width modulation circuit while being contained within an eight-pin integrated circuit.

Abstract: An integrated flyback power converter performing the combined functions of uninterruptible power supply (UPS) and switch-mode power supply (SMPS) is presented. This power converter has a high voltage main power input and a low voltage backup battery input. DC output is obtained from the main input via a flyback power converter during normal operation and from the backup battery via another flyback power converter when input power fails. High conversion efficiency is achieved in normal, backup, and charging modes as there is only a single DC-DC conversion in each mode. The power converter circuit is very simple, with two switching transistors, a relay for mode switching, and a single magnetic structure only. This new design offers substantial improvement in efficiency, size, and cost over the conventional cascade of UPS and SMPS due to single voltage conversion, high frequency switching, and removal of design redundancy. The operation, design, analysis, and experimental results of the power converter are presented.

Abstract: This paper presents an analog implementation of a fast controller for a unity-power-factor (UPF) PWM rectifier. The best settling times of many popular controllers for this type of power converter are on the order of a few line cycles, corresponding to bandwidths under 20 Hz. The fast controller demonstrated in this paper can exercise control action at a rate comparable to the switching frequency rather than the line frequency. In order to accomplish this while maintaining unity power factor during steady-state operation, the fast controller employs a ripple-feedback cancellation scheme.

Abstract: The fourth part of this tutorial series deals with power system interharmonics-those frequencies generated by large power converters which are not integer harmonics of the supply frequency. Previous parts of the series have covered harmonic sources, measurements, calculations, harmonic problems and harmonic reduction.

Abstract: A backup power supply 11 is not loaded by peripheral equipment 9 and a low-voltage battery 5. A switch controller 12 is energized by any of the backup power supply 11, the DC/DC converter 7, and the low-voltage battery 5 for controlling the energization of a relay 3L. When the power supply from the DC/DC converter 7 and the low-voltage battery 5 to the switch controller 12 is declined, it is complemented by the backup power of a low voltage from the backup power supply 11. Accordingly, the switch controller 12 is always energized with a sufficient level of the power supply regardless of the residual storage of the low-voltage battery 5.

Abstract: A power supply of the high frequency series resonant mode family for supplying power to audio amplifiers includes half and full bridge variations and supplies all of the required rail voltages while maintaining fixed frequency resonant operation throughout all combinations of loading of the amplifier outputs without the need for a large explicit resonant inductance. The elimination of switching loss enables the use of power supply switching devices optimized for low conduction loss, further improving performance under high current conditions. The power supply frequency is fixed by an oscillator of sufficient precision to ensure that the beat frequency that will result from heterodyning of the residual switching frequency noise between two identical but separate power supplies will be in the infrasonic range. Protection circuitry is provided to limit peak switch currents during the start up interval. The power supply and power amplifier protection functions are interlinked, resulting in simplified protection against short and long term current overloads, thermal overloads, output load shorts, and amplifier faults leading to DC outputs. The intended application is the reproduction of audio signals, which have a high crest factor, requiring the ability to deliver high short term power levels from a given set of components.

Abstract: A new concept of an intelligent power transformer is presented in this paper, where the size of a power transformer of commercial frequency is miniaturized by introducing a modulator. In this circuit, various functions, such as constant voltage, constant power and power factor correction are realized by a phase control system.

Abstract: A chip has been designed to test the implementation of a PLL-based dynamic supply controller. Separating the rate transitions from V/sub T/ and temperature drift improves loop transient response. Buffering and explicit averaging can be used to smooth workload. Active damping minimizes loss in the supply filter due to voltage transitions.

Abstract: Apparatus and methods for AC power regulation for a wide range of complex capacitive and inductive loads which provide substantial reduction in power consumption while also providing a leading power factor. The system is self-adjusting for a wide range of loads and can reduce power consumption by 25 percent in lighting loads while producing minimal reduction in light output. The system utilizes a main switch consisting of back-to-back MOS Controlled Thyristor devices (MCTs) and a parallel capacitor bank in series with the load. The main switch is initially turned off slightly in advance of the load current zero crossing, and this in combination with the capacitor bank allows power to be reduced in a low noise fashion. The turn-off time is advanced gradually to regulate power at a target reduced level. At the target power level, load phase angle is measured and maintained to control the power savings ratio.