General Electric Company

Mustansir Hussainy Kheraluwala

Eladio Clemente Delgado

Robert Louis Steigerwald

Sayed-Amr A El-Hamamsy

Paul Alan McConnelee

Michael Joseph Schutten

Charles S Korman

Burhan Ozmat

Louis Robert Nerone

Ljubisa Dragoljub Stevanovic

Rui Zhou

David Joseph Kachmarik

Rik W De Doncker

Weizhong Tang

A hot restrike protection circuit provides complete shut down protection for a self-oscillating high intensity discharge lamp ballast of the type comprising a pair of complementary switching devices in a bridge configuration with a gate drive inductor in series with a second inductor, i.e., a control inductor, at the junction between the switching devices. The hot restrike protection circuit effectively comprises a three-terminal device for coupling across the control inductor. In particular, the HRP circuit comprises a sensing network for sensing voltage across the control inductor, a breakdown network for providing a breakdown path upon reaching a predetermined restrike voltage threshold across the control inductor, and a shutdown network for shutting down operation of the ballast until the lamp is sufficiently cool for restarting, thereby protecting ballast components during hot restrike, or re-ignition, of the lamp.

Hot restrike protection circuit for self-oscillating lamp ballast

A method of power electronic packaging includes a practicable and reliable method of fabricating power circuit modules and associated connections that are compatible with the standard top layer metalization of commercially available power devices. A planar single- or multi-layer membrane structure is attached to a carrier frame, and a via pattern is formed in the membrane. Power devices are aligned and attached to the planar membrane structure; a top layer interconnect structure is formed by metalizing the vias and the film; and a circuit is formed by patterning a deposited metal layer. The carrier frame is removed, and upper and lower thermal base plate sub-assemblies are attached to the power device-on-membrane structure. The planar device-on-membrane structure accommodates different types of power devices having variations in thickness. The thermal base plate sub-assemblies may include integral, high-performance heat exchangers for providing a low thermal resistance path to the ambient.

Power electronic module packaging

A control method and apparatus for reducing transformer core volume in a power converter of the type having a switching circuit coupled to a primary winding of the transformer for selectively coupling the primary winding to a dc voltage source, a secondary winding of the transformer being coupled to an output rectifier circuit for developing a relatively high dc voltage across an output capacitor. The apparatus includes a high voltage zener diode clamp for limiting the maximum voltage on the capacitor, and the rectifier circuit includes at least a pair of zener diodes connected for blocking reverse current flow through the rectifier circuit. The method includes the steps of coupling the transformer primary winding to the dc voltage source to establish a relatively short resonant charging pulse for developing an initial charging current to the output capacitor, disconnecting the dc voltage source from the transformer primary winding for a time interval which is relatively long with respect to the charging interval to allow the transformer reactances and resonant capacitor to reset to zero energy conditions, and repeating the steps of coupling and disconnecting until the output capacitor is charged to the zener clamp voltage. A reverse process is used to step-wise discharge the output capacitor.

Bi-directional energy diode converter using multipulse control

A ballast system for at least one dimmable fluorescent lamp includes a resonant switching inverter and a controller which controls the inverter to operate above resonance during starting and normal running operation. After a start delay timer allows time for the lamp filaments to heat up, the controller provides control signals to a gate driver to drive the switching devices of the switching inverter initially at a relatively high frequency and then reduces the frequency until a sufficiently high voltage is reached to start the lamp. Once the lamp is started, the inverter is operated in its normal feedback mode. The ballast system further includes an overvoltage shutdown mechanism. During lamp starting, if either the output of the start delay timer is high or the output voltage is greater than a first overvoltage shutdown threshold, then an overvoltage shutdown timer is activated to shut down operation of the inverter for a predetermined overvoltage shutdown period. After the lamp has started, a second overvoltage shutdown threshold is activated which is lower than the first overvoltage threshold for avoiding operation of the inverter below resonance. Both the frequency and duty cycle of the output voltage from the switching inverter are variable to achieve a wide dimming range over a relatively narrow frequency range.

Florescent lamp ballast control for zero -voltage switching operation

A gate drive latching circuit for an auxiliary resonant commutation circuit for a power switching inverter includes a current monitor circuit providing a current signal to a pair of analog comparators to implement latching of one of a pair of auxiliary switching devices which are used to provide commutation current for commutating switching inverters in the circuit. Each of the pair of comparators feeds a latching circuit which responds to an active one of the comparators for latching the associated gate drive circuit for one of the pair of auxiliary commutating switches. An initial firing signal is applied to each of the commutating switches to gate each into conduction and the resulting current is monitored to determine current direction and therefore the one of the switches which is carrying current. The comparator provides a latching signal to the one of the auxiliary power switches which is actually conducting current and latches that particular power switch into an on state for the duration of current through the device. The latching circuit is so designed that the only time one of the auxiliary switching devices can be latched on is during the duration of an initial firing command signal.

Gate drive latching circuit for an auxiliary resonant commutation circuit

A high-density control circuit for an auxiliary resonant commutation pole (ARCP) circuit is internal to the ARCP package and includes a state machine sequencer for providing control and timing signals to achieve high-efficiency, zero-voltage, and fault-tolerant switching converter operation. The phase leg controller receives as inputs a phase enable signal and a pulse width modulation (PWM) signal from a system controller and gate drive feedback signals from main and auxiliary gate drivers. There are four paths the state machine sequencer can take when making a transition from one dc rail to the other, depending on whether the main diode or main switch is conducting and the magnitude and polarity of the inverter pole output current.

Robust, high-density, high-efficiency state sequence controller for an

A modified valley fill circuit, including a main ballasting inductor for supplying an electrolytic capacitor, has an additional charging winding on the main ballasting inductor for charging the electrolytic capacitor to a predetermined voltage which maximizes the power factor of the input current by optimizing the conduction angle of the input current. In a discharge lamp ballast, the modified valley fill circuit reduces the lamp current crest factor by controlling the frequency with a lamp current control loop.

Modified valley fill high power factor correction ballast

A power distribution system including a dual active bridge converter (DABC) distributes a regulated high-frequency, edge-resonant, square wave ac output voltage from an unregulated dc voltage source. The DABC-includes a primary-side half-bridge connection of switching devices and a secondary-side half-bridge connection of switching devices which are coupled by an intermediate high-frequency transformer. An ac distribution bus is connected to the regulated secondary side of the transformer. The primary-side and secondary-side connections of switching devices are phase-shifted in a manner to provide a regulated high-frequency square-wave voltage on the ac distribution bus, which is distributed via a low-impedance distribution bus to a plurality of simple point-of-load converters. Alternatively, a plurality of DABC's is configured in a high-frequency ac power distribution system such that a primary-side half-bridge of switching devices converts an unregulated dc voltage source to an unregulated high-frequency, square wave ac voltage which is distributed to a plurality of point-of-load converters. Each point-of-load converter has a high-frequency transformer and secondary-side switching devices, such that each point-of-load converter forms a DABC pair with the primary-side half-bridge.

Power distribution system for generating regulated DC output voltages

A multi-resonant boost power factor correction circuit includes a full-wave rectifier; a high frequency filter capacitance coupled across the input terminals of the full-wave rectifier; a series half-bridge converter; a diode connected between the output of the rectifier and the dc bus voltage such that its cathode is connected to a dc bus; a capacitance coupled between the output of the rectifier and the junction between the series-connected switching devices of the half-bridge converter; a resonant load circuit connected to the junction between the switching devices, including a resonant inductor, a resonant capacitor and a load, such as a fluorescent discharge lamp; and a driver circuit for alternately switching the switching devices via a dead time control for selecting a dead time after one of the devices switches off and the other device switches on. The multi-resonant boost high power factor circuit meets the IEC standard for low harmonic content on input current, thus operating with a very high power factor, and operates with a minimal number of circuit components. In addition, the circuit meets lamp current crest factor specifications for fluorescent discharge lamp ballasts and requires lower voltage power devices.

Multi-resonant boost high power factor circuit

A high efficiency, high power factor, low voltage power converter includes a dual active bridge converter (DABC) having transformer-coupled primary-side and secondary-side bridge connections of switching devices and providing two output voltages. One output voltage drives a resonant boost converter coupled in series between an ac rectifier for rectifying an ac line voltage and the DABC. The boost converter, which is controlled by frequency modulation, boosts a dc bus voltage above the peak line voltage, thereby providing a high power factor. The other output is a low dc voltage which is regulated by controlling the phase shift between the voltages respectively produced by the primary-side and secondary-side connections of switching devices of the DABC. Advantageously, the leakage inductance of the DABC transformer coupling the primary and secondary sides of the DABC is efficiently used for energy transfer therebetween such that an output filter inductor is not needed. Moreover, use of synchronous rectifiers in the DABC allows for active control on the secondary side of the DABC transformer, further increasing efficiency. Zero-voltage switching of the switching devices of the DABC allows for an increase in operating frequency and hence an increase in power density.

Efficient, high power density, high power factor converter for very low

A fixed duty ratio, variable frequency, square wave generator includes an astable multivibrator having a pair of resistors coupled in series between a supply voltage terminal and a capacitor, such as of a type implemented with a 555 timer, and further includes a JFET connected between the capacitor and ground. In a current-controlled version, the anode of a diode is connected to the gate of the JFET, and the cathode of the diode is connected to a sensing resistor for sensing current in a load. The multivibrator generates a ramp voltage across the capacitor which varies between predetermined fractions of the supply voltage with a fixed duty ratio. The capacitor of the multivibrator charges and discharges through the series connection of the resistors and the JFET channel resistance with charging and discharging times that vary with the input voltage to the JFET, thereby varying the generator frequency.

Variable frequency generator for resonant power feedback

A dual active bridge converter, including high-frequency transformer-coupled input and output bridge converters, receives a rectified ac line voltage via a rectifier acting in a resistive mode and a small, high-frequency filter capacitor. A phase angle controller controls a phase shift between the voltages across the transformer windings such that high-efficiency dc-to-dc conversion is achieved, while maintaining unity power factor at the ac input, using high-density circuitry with small filter components and without adding additional front-end power factor correction circuitry.

Unity power factor control for dual active bridge converter

A method and system for controlling a dual output power converter of the type having a pair of input terminals connectable to a source of rectified AC power of variable voltage amplitude, a boosting circuit including a secondary winding of a boost transformer operatively coupled in circuit with the pair of input terminals for providing a boosted voltage onto a DC power bus, and a full-bridge inverter including at least one controllable switching device serially connected in each leg of the inverter. The inverter has an input connected to the DC bus and a pair of output terminals connected to respective ends of a primary winding of an output transformer, at least one of the pair of output terminals being connected in circuit with the primary winding of the boost transformer. The control system compares signals representative of the magnitude of the AC power voltage to signals representative of the DC bus voltage and varies the inverter frequency of operation in a manner to adjust the magnitude of the DC bus voltage to establish a preselected ratio of DC bus voltage to AC power voltage.

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Schenectady, NY, United States of America

Mustansir Hussainy Kheraluwala