Siliconsystems, Inc.

Siemens Power Transmission & Distribution, Inc.

Richard D Davis

Jeff Kotowski

John T Voisine

Gordon R Burns

John P Junker

Javier Adame

John Parry

A watt-hour meter employs a power factor compensation technique that inserts a delay into the digitized current or voltage sample stream. An exemplary embodiment of the present invention includes an electronic watt-hour meter comprising a voltage sensor, a current sensor, a conversion circuit, and a processing circuit: The voltage sensor generates a voltage measurement signal responsive to a voltage provided to a load. Similarly, the current sensor generates a current measurement signal responsive to a current provided to a load. The conversion circuit further comprises: a first converter connected to the voltage sensor for generating sampled voltage data stream based on said voltage measurement signal; a second converter connected to the current sensor for generating a sampled current data stream based on said current measurement signal, and a phase correction circuit. The phase correction circuit is connected to one of the first and second converters and inserts a delay into one of the sampled voltage data stream or the sampled current data stream. The processing circuit is operably connected to the first and second converters, and receives information indicative of the sampled voltage data stream and sampled current data stream subject to any delay inserted by the phase correction circuit. The processing circuit then generates power consumption data from the sampled voltage data and sampled current data.

Watt-hour meter with digital per-phase power factor compensation

The present invention discloses method and apparatus for offset and phase correction in multiplexed delta-sigma modulators. According to the invention, offsets and phases of input signals to multiplexed delta-sigma modulators are corrected by a simple and low cost method. The invention utilizes a novel switching technique during different sampling periods to eliminate the effect of DC offsets present in multiplexed input signals. The invention also uses a delay introduced by a FIFO or a shift register to individually correct for phase shifts present in individual multiplexed input signals. The invention accomplishes these objectives without introducing a significant quantization noise, and without requiring overlapping FIR filters.

Offset and phase correction for delta-sigma modulators

A programmable system synchronizes the operation of an electronic angular position indicator with the angular displacement of a rotor. The system can synchronize operation with rotors with non-uniform mark spacing. A sensor provides the system with electronic pulse patterns corresponding to marks on the rotor. Pulse patterns are compared to patterns stored in memory to determine the instantaneous angular position of the rotor. The synchronization system provides the angular position indicator with parameters appropriate to the angular position of the rotor. The system obtains synchronization during initial rotations of the rotor and continually checks synchronization during subsequent rotation.

Programmable system for the synchronization of an electronic angular

An improved method for current limiting applications to control the current through MOSFETs or IGBTs. An amplifier having a single, high-frequency pole is used to drive the large gate capacitance of a power MOSFET or IGBT. The current in the power transistor generates a negative feedback voltage in a sensing resistor. This feedback voltage is compared with a reference voltage to determine the output voltage of the amplifier. This provides greater stability for driving IGBT transistors, and the actual frequency response is only dependent upon the poles generated by the power transistor and its load. The current in the transistor ramps up to a value determined by the reference voltage, and then settles to a constant value with little or no overshoot or oscillation.

Current limit circuit for IGBT spark drive applications

A programmable, electronic, angular position indicator, based upon engineering units, estimates the angular displacement of a rotating rotor. The angular position indicator is programmed with the particular arrangement of teeth (or other markings) on the rotor. Intermediate angular displacements are interpolated between a limited number of positive angular displacement indications. Offsets, due to acceleration or deceleration of the rotor, are corrected at each positive angular displacement indication without skipping the output of each interpolated angular displacement. Angular displacement is determined in standard engineering units.

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Nevada City, CA, United States of America

Richard D Davis