Abstract: A power converter includes a first rectifier circuit having a pair of first rectifier circuit output terminals and a second rectifier circuit having a pair of second rectifier circuit output terminals, a snubber circuit comprising a first diode and a first capacitor connected to each other at a first node and connecting the pair of first rectifier circuit output terminals, a second diode and a second capacitor connected to each other at a second node and connecting the pair of second rectifier circuit output terminals, a third diode connecting the first node to one of the pair of second rectifier output terminals, and a fourth diode connecting the second node to one of the pair of first rectifier output terminals.

Abstract: An impedance measurement circuit includes a signal injector having a voltage input and a voltage output, a controllable switch, and a voltage drop device connected in parallel with the controllable switch between the voltage input and the voltage output. The voltage output is connected to a load. A voltage sensor is configured to measure a voltage across the load. A current sensor is configured to measure a current draw of the load. A computing device is configured to determine an impedance of the load at a frequency based on the measured voltage and the measured current. The computing device controls the switch based on the frequency.

Abstract: A power converter includes a first rectifier circuit having a pair of first rectifier circuit output terminals and a second rectifier circuit having a pair of second rectifier circuit output terminals, a snubber circuit comprising a first diode and a first capacitor connected to each other at a first node and connecting the pair of first rectifier circuit output terminals, a second diode and a second capacitor connected to each other at a second node and connecting the pair of second rectifier circuit output terminals, a third diode connecting the first node to one of the pair of second rectifier output terminals, and a fourth diode connecting the second node to one of the pair of first rectifier output terminals.

Abstract: An impedance measurement circuit includes a signal injector having a voltage input and a voltage output, a controllable switch, and a voltage drop device connected in parallel with the controllable switch between the voltage input and the voltage output. The voltage output is connected to a load. A voltage sensor is configured to measure a voltage across the load. A current sensor is configured to measure a current draw of the load. A computing device is configured to determine an impedance of the load at a frequency based on the measured voltage and the measured current. The computing device controls the switch based on the frequency.

Abstract: A power supply provides dc power over a wide range of output voltages at full operating power by utilizing multiplying circuits (200) supplied by a source of high-frequency alternating current (90). The multiplier circuits include a plurality of multiplier cells containing at least two diodes (207, 209) and a driving capacitor (208). The multiplier cells are shunted by bypass rectifiers (205, 206) arranged such that currents are allowed to flow from multiplier input terminals to power supply output terminals. The bypass rectifiers do not conduct current for low output current levels, but conduct increasing levels of current when output currents increase beyond a conduction threshold value, thereby increasing the maximum available output current. Interactions among the diodes and capacitors in the multiplier circuits cause the amplitudes of the multiplier input currents to remain relatively constant as the output voltage is varied while operating at full power.

Abstract: A power supply provides dc power over a wide range of output voltages at full operating power by utilizing multiplying circuits (200) supplied by a source of high-frequency alternating current (90). The multiplier circuits include a plurality of multiplier cells containing at least two diodes (207, 209) and a driving capacitor (208). The multiplier cells are shunted by bypass rectifiers (205, 206) arranged such that currents are allowed to flow from multiplier input terminals to power supply output terminals. The bypass rectifiers do not conduct current for low output current levels, but conduct increasing levels of current when output currents increase beyond a conduction threshold value, thereby increasing the maximum available output current. Interactions among the diodes and capacitors in the multiplier circuits cause the amplitudes of the multiplier input currents to remain relatively constant as the output voltage is varied while operating at full power.

Abstract: An interleaved soft switching bridge power converter comprises switching poles operated in an interleaved manner so as to substantially reduce turn-on switching losses and diode reverse-recovery losses in the switching pole elements. Switching poles are arranged into bridge circuits that are operated so as to provide a desired voltage, current and/or power waveform to a load. By reducing switching turn on and diode reverse recovery losses, soft switching power converters of the invention may operate efficiently at higher switching frequencies. Soft switching power converters of the invention are well suited to high power and high voltage applications such as plasma processing, active rectifiers, distributed generation, motor drive inverters and class D power amplifiers.

Abstract: An interleaved soft switching bridge power converter comprises switching poles operated in an interleaved manner so as to substantially reduce turn-on switching losses and diode reverse-recovery losses in the switching pole elements. Switching poles are arranged into bridge circuits that are operated so as to provide a desired voltage, current and/or power waveform to a load. By reducing switching turn on and diode reverse recovery losses, soft switching power converters of the invention may operate efficiently at higher switching frequencies. Soft switching power converters of the invention are well suited to high power and high voltage applications such as plasma processing, active rectifiers, distributed generation, motor drive inverters and class D power amplifiers.

Abstract: A power supply system is disclosed. In one embodiment the power supply system includes a source of DC power that provides a DC bus voltage between a pair of DC bus terminals, and a power supply that receives power from the DC bus terminals and delivers power to a load. An output measurement circuit measures output parameters delivered by the power supply and provides a corresponding set of feedback signals. A feedback regulator connected receives the feedback signals and provides a feedback output signal operative to regulate the output of the power supply to achieve a desired voltage, current, or power level specified by a setpoint signal. An adaptive feedforward circuit connected to the feedback regulator and to the DC bus terminals provides a combined regulation signal to the power supply that minimizes perturbations in the output of the power supply due to DC bus ripple voltage.

Abstract: A carbonation system is disclosed that effectively controls the treatment of fruits and vegetables with CO2 gas, providing enhanced flavor to fruits and vegetables. One embodiment of the invention uses a microprocessor to preferably monitor and control the pressure, temperature and gas flow within a sealable enclosure to effectively control the carbonation of fruits and vegetables. Another embodiment consists of a combination carbonation system and cooler that effectively controls the carbonation of fruits and vegetables by including pressure relief devices and an insulation cover. The insulation cover has apertures that provide for the distribution of CO2. A third embodiment is disclosed that also consists of a combination carbonation system and cooler. This third embodiment controls carbonation by including, among other features, feedback mechanisms and a pressure relief device. A method of using the first embodiment is also provided.

Abstract: There is provided by this invention soft switching interleaved power converters that are suitable for high power and high voltage applications such as plasma processing. They have greatly reduced switching losses and diode reverse-recovery losses which allows operation at high switching frequencies. The peak values of the reverse-recovery currents of the diodes are substantially less then their peak forward operating currents. The power converters incorporate power converter cells that comprise a plurality of switching assemblies that are operated with an interleaved switching pattern, and that are each connected to an input terminal of an inductor assembly that also has a common terminal. The inductance between each pair of input terminals is less than the inductance between each input terminal and the common terminal of the inductor assembly.

Abstract: A carbonation system is disclosed that effectively controls the treatment of fruits and vegetables with CO2 gas, providing enhanced flavor to fruits and vegetables. One embodiment of the invention uses a microprocessor to preferably monitor and control the pressure, temperature and gas flow within a sealable enclosure to effectively control the carbonation of fruits and vegetables. Another embodiment consists of a combination carbonation system and cooler that effectively controls the carbonation of fruits and vegetables by including pressure relief devices and an insulation cover. The insulation cover has apertures that provide for the distribution of CO2. A third embodiment is disclosed that also consists of a combination carbonation system and cooler. This third embodiment controls carbonation by including, among other features, feedback mechanisms and a pressure relief device. A method of using the first embodiment is also provided.

Abstract: There is provided by this invention a dc power supply that utilizes capacitors in parallel with the diodes of the rectifier bridge in order to increase the full-power load impedance range of the power supply. In addition it has the capability to selectively couple the capacitors to the diodes over a predetermined frequency. This invention applies to both single phase and multiphase converters.

Abstract: There is provided by this invention a dc power supply that utilizes capacitors in parallel with the diodes of the rectifier bridge in order to increase the full-power load impedance range of the power supply. In addition it has the capability to selectively couple the capacitors to the diodes over a predetermined frequency. This invention applies to both single phase and multiphase converters.

Abstract: An electronic ballast having a through-lamp ground fault sensor that may also function as an end-of-lamp-life sensor is disclosed. The electronic ballast has an inverter that receives power from a dc power supply, and delivers a high-frequency output voltage to a resonant tank circuit through a dc blocking capacitor. The ground fault sensor includes a filter circuit connected to a voltage sensor circuit. An input terminal of the filter circuit is connected to the resonant tank so as to be in communication with a voltage signal that exists between a ballast output terminal and a dc power supply output terminal. The filter provides a filtered voltage signal by attenuating high frequency ac voltage components of the voltage signal, and passing low frequency ac voltage components, such as a 60 Hz signal, and possibly also passing a dc voltage component. A through-lamp ground fault will generate a voltage signal at the power line frequency.

Abstract: An electronic ballast apparatus for powering one or more gas discharge lamps includes an inverter that is controlled by an inverter control circuit. The inverter control circuit adjusts certain ballast operating characteristics in order to operate the lamps under nearly the same operating conditions irrespective of how many lamps are connected to the ballast. The inverter control circuit includes a lamp quantity sensor, a regulator circuit and an end-of-lamp-life sensor. The lamp quantity sensor provides a lamp quantity signal that indicates how many lamps are connected to the ballast. The regulator circuit includes a reference adjustment circuit that receives the lamp quantity signal and provides a scaled reference signal to a reference terminal of an error amplifier. The error amplifier also has a feedback terminal that receives a signal that is proportional to the power delivered by the inverter to the lamps.

Abstract: A dimming control interface for dimming ballasts is disclosed. The control interface includes DC voltage source input terminals in series with a pair of input terminals and a high-voltage resistance element to form a current source. The dimming control interface includes an isolated coupling element connected between a pair of dimming control input terminals and a pair of dimming control output terminals, and is operative to generate an output control voltage in response to an input control voltage applied to the input terminals. The dimming control interface further includes voltage clamping element to limit voltages generated in the control interface to safe levels when an external AC power source is connected to the dimming control interface. Similarly, a second high voltage resistance element is connected between one of the dimming control input terminals and the isolated coupling element to limit currents generated by the AC power source to safe levels.

Abstract: A symmetry control circuit for a ballast driving a gas discharge lamp. The circuit controls the pre-heat time of a gas discharge lamp with heatable filaments by holding off the full striking voltage until the lamp has had sufficient time to pre-heat. The circuit is designed to work with electronic ballasts and especially electronic ballasts without boost power factor correction to properly pre-heat the lamp. A control circuit reduces the duty cycle in an inverter transistor, thereby keeping the voltage across the lamp low while allowing filament heating to occur. The control circuit is disabled after a time interval of about 500 ms, allowing the transistor duty cycle to increase to 50 percent, the lamp voltage to rise, and the properly pre-heated lamp to ignite.

Abstract: A family of programmed start parallel-resonant electronic ballast circuits operate in a first mode during a preheat interval following application of power to the ballast, and then afterwards operate in a second mode. The ballast circuits can be based on any of the several forms of current-fed parallel-resonant inverters, all of which have a dc choke inductor. A first embodiment operates such that, during the first mode, the parallel-resonant inverter is inhibited, while an auxiliary transistor develops a trapezoidal voltage waveform across the dc choke inductor. Filament preheating is provided by windings coupled to the dc choke inductor. The ballast output voltage is essentially zero so that no destructive glow current is produced. During the second mode, the auxiliary transistor is inhibited, and the parallel-resonant inverter produces a sinusoidal output voltage.

Abstract: A pulse-width modulator is disclosed which can be used, for example, in a power factor corrected electronic ballast circuit. The pulse-width modulator circuit combines a reference waveform signal with a second signal to form a composite waveform signal. The composite waveform signal is then compared with a reference voltage. The level of the pulse-width modulator's output depends upon the results of the comparison, such that a change in the level of the second signal causes an adjustment in the duty cycle of the output. In an electronic ballast application, the reference waveform can be a scaled version of the oscillator waveform found in the ballast's inverter circuit.