Abstract: A lamp power measurement circuit measures average power delivered to a gas discharge lamp. The circuit includes a voltage sensor having a first measurement output representative of AC voltage across the lamp and a current sensor having a second measurement output representative of AC current through the lamp. A first absolute value circuit is coupled in series with the first measurement output and has a first absolute value output. A second absolute value circuit is coupled in series with the second measurement output and has a second absolute value output. A pulse width modulator modulates one of the first and second absolute value outputs with the other of the first and second absolute value outputs and has a pulse width modulated output. A low-pass filter is coupled in series with the pulse width modulated output and has a DC voltage output representative of average power dissipated through the lamp.

Abstract: An inductive charger includes a rectifier that can be connected to both single- and three-phase power sources. The rectifier includes first, second and third legs that include first and second diodes. Alternately, the third leg includes first and second silicon-controlled rectifiers. A capacitor is connected across an output of the rectifier. An inverter is connected to the rectifier and the capacitor and includes a plurality of switching circuits. A series resonant tank circuit is connected to an output of the inverter. A charge coupler and an inductive inlet include a transformer and a parallel resonant tank circuit for coupling energy to a load. A controller is connected to the rectifier and the inverter. The controller generates drive signals for controlling the switching circuits. The inductive charger is capable of providing approximately 0.99 power factor from single-phase and 0.91 power factor at twice the output power from three-phase power sources.

Abstract: A method and an apparatus for charging one or more electric vehicles includes a first power converter and a second power converter connectable to a source of electric power to receive electric power therefrom. A switch selectively connects the power converters together to provide combined power to a first power coupler in order to charge one electric vehicle, or connects the power converters to separate power couplers in order to charge a plurality of vehicles.

Abstract: An apparatus and method for testing a battery charger includes a converter having input terminals connectable to a battery charger for receiving a current, output terminals and a switching device for electrically connecting at least one of the input terminals to the output terminals. A load is connected to the output terminals. A controller controls the switching device to periodically connect the input terminals to the output terminals, and in a preferred embodiment, maintain a desired voltage across the input terminals.

Abstract: A method and apparatus for charging batteries of a plurality of vehicles includes a power source converter connectable to a power source to receive electrical power and for converting the electrical power to a selected voltage potential that is distributed on a distribution bus. A plurality of vehicle connecting stations are connected to the distribution bus. Each vehicle connecting station includes a station power converter for receiving electrical power from the power source converter for charging the battery and a station controller to control electrical power flow to the vehicle battery.

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.

Abstract: A full bridge switching power converter employs zero-voltage, resonant-transition (ZVRT) switching techniques which appreciably reduces the switching losses at high switching frequencies, (for example, 1 MHz and above), using constant frequency, pulse-width-modulation techniques. The converter is implemented using a transfer with four switching FET's coupled to the primary of the transformer and four switching FET's coupled to the output of the transformer and a control unit that supplies the constant waveforms necessary to achieve synchronization and timing required to achieve the ZVRT switching.

Abstract: A voltage regulator particularly adapted to A.C. distributed power systems requiring independent voltage regulation at a plurality of frequency responsive power supply modules energized by a power source at a common alternating frequency is provided by resonant tuning of the regulator circuit. An LC resonant circuit determines the operating frequency of the regulator, and may be operated above or below the excitation frequency. The output voltage is applied to a current amplifier which energizes a linearly variable inductor in accordance with the sensed D.C. output voltage. Changes in the output voltage result in changes in the tuned frequency of the LC circuit and the corresponding corrective change in the output voltage. Circuits providing both voltage and current regulation are described.

Abstract: A regulator circuit for equalizing the load currents of a plurality of power supply modules connected in common to feed a common load. Each of the modules includes a pulse-width modulator for adjusting the duty cycle of the module, thereby to adjust the voltage regulation point and corresponding current output of the module. A current sensor produces a current level signal proportional to the current output of the module. The current level signal is applied through a current amplifier to generate a corresponding variable error voltage. A fixed reference voltage derived from the output voltage and the variable error voltage are applied to the pulse-width modulator to vary the duty cycle so as to produce a decrease in load voltage with an increase in current output and an increase in the load voltage with a decrease in current output thereby equalizing the current output of the module with modules having substantially equal output voltages.

Abstract: A single stage power conditioner which produces an isolated DC output while drawing resistive input current from the utility has been described. A high frequency switch-mode technique was used which operates in continuous conduction mode to reduce electro-magnetic interference (EMI) generation and ripple losses.

Abstract: A full bridge DC-DC series-resonant power converter is operated at a constant switching frequency using a phase delay between the transistor legs of the bridge to control the output voltage. All power semiconductor devices switch on and switch off at approximately zero volts while operating at a constant switching frequency which is above the resonant frequency of the resonant tank circuit. Zero-voltage switching increases the efficiency of the power converter and allows high frequency operation which minimizes component volumes. Constant frequency operation simplifies design of the magnetic components, confines the EMI spectrum to known frequencies and simplifies EMI design, and reduces the voltage and current excursions and thus reduces the peak component stress.

Abstract: An A.C. to D.C. power conditioner, which draws sinusoidal input current utilizes digital proportional-integral control to provide output voltage regulation by adjusting the gain of a current program loop. The current program loop controls the state of a power switch to force the instantaneous average current in an inductor to follow the instantaneous rectified line voltage. Variable hysteresis control provides noise immunity by increasing the ripple current in an iron-cored filter inductor when the instantaneous input voltage is high. Digital proportional-integral (PI) control provides output voltage regulation by adjusting, in discrete steps, the gain of the current program loop. A multiplying digital-to-analog converter serves as an interface between the voltage regulation loop and the current program loop. The sampling rate of the PI controller is determined by the input line frequency, which allows good transient response to be obtained.

Abstract: A pair of quantized duty ratio proportional-integral-differential (PID) converters are coupled to provide power sharing to a load. One of the converters is a master and the other is a slave, and a PID controller is coupled to both of the converters. The PID controller also supplies two digital offset signals to the converters during normal operation, which insures load sharing by control of the duty ratio of the converters. If one of the converters fails, a sensor control unit switches control to the other unit and the digital offset signal goes to zero.

Abstract: A digital power converter input current control circuit is connected between a power converter and a power source. This circuit monitors, and controls if necessary, the current that flows between the power source and the power converter in a manner that protects the power source, the input current control circuit, and the power converter from the catastrophic effects of excessive current flow. The input current control circuit operates similar to an electronic circuit breaker with an automatic reset feature, in that the power delivered to the power converter is maintained low during fault conditions. Thus, if a power transistor in the power converter should fail, a current limit circuit in the input current control circuit will prevent additional damage to the power converter.

Abstract: A discrete proportional-integral-differential controller, driven from a sampling digital error amplifier, is used to penetrate a quantized duty ratio control signal to provide dynamic output voltage regulation for switching dc-to-dc power converters. The sampling frequency of the digital PID controller is equal to the switching frequency of the power converter, so the digital controller may be used at different switching frequencies without recompensation. Digital techniques are also used to provide output current limiting, soft-start, undervoltage lockout, overvoltage shutdown, and power master-clear indications.

Abstract: A biasing network comprising two nominal type GZ 2422D transorbs, two resistors nominal 68 ohms and one resistor nominal 110 ohms replicated at each combined differential current driver of nominal type Am26L531 and differential receiver of nominal type Am26L532, as jointly form a transceiver, which are upon a two-wire differential signal communication path allows communication to transpire at a common-mode offset voltage, nominally .+-.8 volts, which is greater than the differential signal voltage that the receiver does elsewise communicate at, and which common-mode offset voltage is at a level which might but for the biasing network damage or destroy the driver.