Xantrex Technology Inc.

Distributed Power, Inc.

Schneider Electric Solar Inverters USA, Inc.

Utility Power Group

Rick West

Arthur F Dickerson

The invention is a device and method for eliminating core excitation losses in a distribution transformer when the transformer is not supplying power to loads. The invention consists of sensors, a control circuit, a user interface and a power contactor. The power contactor is connected on the line side of a transformer and is opened or closed automatically based on preprogrammed time or load criteria determined by the control circuit. In one operational mode and when the transformer is disconnected from the line, the control board generates low power pulses at the transformer load connection points in order to 'search' for loads. If a load is detected, the transformer is reconnected by way of contactor closure. If the transformer load drops to zero, for a predetermined amount of time, the transformer is again disconnected and the pulsed load search is reestablished.

Device and method for eliminating transformer excitation losses

A combiner circuit and voltage protection circuit is disclosed. A plurality of photovoltaic sources is provided. A set of fuses, each having one side coupled to one of the plurality of photovoltaic sources is provided. A set of contacts, each having one side coupled to the other side of one of the fuses is provided. The other side of the contacts are coupled together to combine the output of the photovoltaic sources to an output interface, the output interface being coupled to the load. A set of diodes are each coupled to each of the set of fuses and form a current path around the set of contacts. A transistor is coupled to each of the diodes and the load interface. The transistor has an on state completing the flow of current through the diodes around the set of contacts to the load interface.

Integrated photovoltaic source circuit combiner and protection subsystem

An electrical DC-to-AC power conversion apparatus is disclosed that is primarily intended for use with solar photovoltaic sources in electric utility grid-interactive applications. The invention improves the conversion efficiency and lowers the cost of DC-to-AC inverters. The enabling technology is a novel inverter circuit topology, where the bulk of the throughput power, from DC source to AC utility, is processed only once. The inverter does not require an isolation transformer and can be connected directly to a 480/277 Vac utility grid. The invention also allows the power converter to start into photovoltaic array having higher open circuit voltages. The invention also uses active ripple current cancellation to substantially reduce the cost, size and weight of the main filter inductors.

Transformerless utility-grid-interactive inverter

An apparatus and method of control for converting DC (direct current) power from a solar photovoltaic source to AC (alternating current) power. A novel DC-to-AC power converter topology and a novel control method are disclosed. This combination of topology and control are very well suited for photovoltaic microinverter applications. Also, a novel variant of this control method is illustrated with a number of known photovoltaic DC-to-AC power converter topologies. The primary function of both control methods is to seek the maximum power point (MPP) of the photovoltaic source with novel, iterative, perturb and observe control algorithms. The control portion of this invention discloses two related control methods, both an improvement over prior art by having greatly improved stability, dynamic response and accuracy.

Photovoltaic DC-to-AC power converter and control method

An electrical DC-to-AC power conversion apparatus is disclosed that is primarily intended for use with solar photovoltaic sources in electric utility grid-interactive applications. The invention improves the conversion efficiency and lowers the cost of DC-to-AC inverters. The enabling technology is a novel inverter circuit topology, where throughput power, from DC source to AC utility, is processed a maximum of 1&#xbd; times instead of 2 times as in prior-art inverters. The AC inverter output configuration can be either single-phase, split-phase or poly-phase.

Monopolar DC to bipolar DC to AC converter

The invention is a method and apparatus for supplying both positive and negative gate drive power supply potentials to the top switch, in a typical half-bridge semiconductor power topology, from the bottom switch gate drive power supplies and without the use of transformer, capacitive or optical isolation. A known method of providing the positive top switch gate drive supply is enhanced and used in conjunction with a new and novel method for providing the negative top switch gate drive supply. The negative top switch gate drive supply is provided by an additional, lower power semiconductor switch, which is substantially synchronized with the bottom semiconductor switch, except for a slight turn-on delay. When this additional switch is gated 'on' and conducting, the negative bottom switch gate drive power is connected to the negative top switch gate drive supply energy storage capacitors.

Bipolar bootstrap top switch gate drive for half-bridge semiconductor power topologies

This invention is a multi-port power converter where all ports are coupled through different windings of a high frequency transformer. Two or more, and typically all, ports have synchronized switching elements to allow the use of a high frequency transformer. This concept and type of converter is known. This invention mitigates a number of limitations in the present art and adds new capabilities that will allow applications to be served that would otherwise not have been practical. A novel circuit topology for a four-quadrant AC port is disclosed. A novel circuit topology for a unidirectional DC port with voltage boost capabilities is disclosed. A novel circuit topology for a unidirectional DC port with voltage buck capabilities is disclosed. A novel circuit for a high efficiency, high frequency, bi-directional, AC semiconductor switch is also disclosed.

Bi-directional multi-port inverter with high frequency link transformer

A control system for maximizing the power supplied by an array of solar cells senses the current and voltage produced and multiplies these to determine the instantaneous power. The array is tilted slightly in a first direction and the effect on the instantaneous power is noted. If an increase in power was produced, a further movement in the same direction is executed; but if the first movement produced a reduction in power, a movement in the opposite direction is executed. The process continues until no increase in power is obtained in either direction. Thereafter, the same process is carried out with respect to a second axis of the solar array.

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Pismo Beach, CA, United States of America

Rick West