ARCHITECTURE FOR POWER PLANT COMPRISING CLUSTERS OF POWER-GENERATION DEVICES

• US 20100295383A1
• Filed: 05/19/2010
• Published: 11/25/2010
• Est. Priority Date: 05/19/2009
• Status: Active Grant

• Current Assignee: Cool Earth Solar Inc., Maxout Renewables, Inc.
• Original Assignee: Cool Earth Solar Inc.
• Inventors: Cummings, Eric Bryant
• Granted Patent: US 8,786,139 B2
• Time in Patent Office: Days
• US Class Current: 307/151
• CPC Class Codes: H01L 31/02021 for solar cells electrical connection means, e.g. junction boxes, specially adapted for structural association with photovoltaic modules H02S40/34
• CPC Class Codes: H02J 1/102 being switching converters H02J1/108, H02J1/12 take precedence
• CPC Class Codes: H02J 1/106 for load balancing, symmetrisation, or sharing
• CPC Class Codes: H02J 3/00 Circuit arrangements for ac mains or ac distribution networks
• CPC Class Codes: H02M 1/0043 Converters switched with a phase shift, i.e. interleaved non-isolated DC/DC converters H02M3/1586
• CPC Class Codes: H02M 7/493 the static converters being arranged for operation in parallel
• CPC Class Codes: Y02E 10/52 PV systems with concentrators
• CPC Class Codes: Y02E 10/56 Power conversion systems, e.g. maximum power point trackers
• CPC Class Codes: Y10T 29/49826 Assembling or joining

Abstract

Various techniques are employed alone or in combination, to reduce the levelized cost of energy imposed by a power plant system. Solar energy concentrators in the form of inflated reflectors, focus light onto photovoltaic receivers. Multiple concentrators are grouped into a series-connected cluster that shares control circuitry and support structure. Individual concentrators are maintained at their maximum power point via balance controllers that control the flow of current that shunts this series connection. DC current from clusters is transmitted moderate distances to a centralized inverter. The inductance of transmission lines is maximized using an air-spaced twisted pair, enhancing the performance of boost-type three phase inverters. Cluster outputs are separate from individual inverters in massively interleaved arrays co-located at a central location. Step-up transformers convert inverter voltages to grid voltages, and small transformers provide isolation and voltage step-up only on receiver-to-receiver imbalance currents, typically <20% of the total current.

Claims

1. An apparatus for balancing power output comprising:

an array of balancers coupled with a cluster of power-generating elements that are coupled in series via a conductor through which a common current flows, the array of balancers having an output coupled in parallel,

wherein the array of balancers is configured to;

unidirectionally draw current from the power generating elements;

unidirectionally supply current to the power-generating elements; and

bidirectionally pass current through shunt paths,

wherein each power-generating element in the cluster of power generating elements operates independently at a maximum power to supply a total current different from the common current.

2. The apparatus of claim 1 wherein the array of balancers comprises:

a first balancer comprising first, second, third, and fourth terminals, and

a second balancer comprising first, second, third, and fourth terminals, and wherein,

the first terminal and second terminal of the first and second balancers are in respective electronic communication with a first and a second terminal of a first and a second power-generating element,

the third terminals of the first and second balancers are in electronic communication with an output terminal, and

the fourth terminals of the first and second balancers are in electronic communication with a current return terminal.

3. The apparatus of claim 1 further comprising an isolation step-up transformer configured to step up a voltage of at least one power generating element to a voltage of the cluster of power generating elements.

4. An apparatus for balancing power output comprising:

an array of balancers coupled with a cluster of power-generating elements that are coupled in series via a conductor through which a common current flows, the array of balancers each being coupled to a separated isolated winding of a single transformer,

wherein the array of balancers is configured to bidirectionally pass current between balancers, and

wherein each power-generating element of the cluster of power generating elements operates independently at a maximum power to supply a total current different from the common current.

5. A power harvesting apparatus comprising:

at least ten clusters comprising a plurality of power-generating elements configured to output a DC current;

an interleaved inverter having at least ten input terminals, and an output terminal;

at least ten transmission lines having a first end coupled to one of the clusters, and having a second end coupled to a respective one of the ten input terminals.

6. The apparatus of claim 5 wherein the transmission lines comprise air-twisted pairs exhibiting an inductance that supplements at least one inductor in the inverter.

7. The apparatus of claim 6 wherein the transmission lines comprise a magnetic spacer.

8. The apparatus of claim 6 wherein the transmission lines are flattened.

9. The apparatus of claim 5 wherein the interleaved inverter is configured to use interleave timing to reduce switching losses.

10. The apparatus of claim 5 wherein the interleaved inverter is configured to use interleave timing to reduce electromagnetic interference and/or radio frequency interference.