Device for distributed maximum power tracking for solar arrays

• US 7,839,022 B2
• Filed: 07/12/2005
• Issued: 11/23/2010
• Est. Priority Date: 07/13/2004
• Status: Active Grant

• Current Assignee: Tigo Energy, Inc
• Original Assignee: Tigo Energy, Inc
• Inventors: Wolfs, Peter
• Primary Examiner(s): Riley; Shawn
• Application Number:
  US11/571,603
• Publication Number:
  US 20080303503A1
• Time in Patent Office: 1,960 Days
• Field of Search: 323/299, 323/284, 323/906, 323/285, 307/75, 307/77
• US Class Current: 307/77
• CPC Class Codes: G05F 1/67 to the maximum power available from a generator, e.g. from solar cell
• CPC Class Codes: G05F 5/00 Systems for regulating electric variables by detecting deviations in the electric input to the system and thereby controlling a device within the system to obtain a regulated output
• CPC Class Codes: H02J 7/345 using capacitors as storage or buffering devices
• CPC Class Codes: H02J 7/35 with light sensitive cells
• CPC Class Codes: H02M 1/0077 Plural converter units whose outputs are connected in series
• CPC Class Codes: H02M 3/158 including plural semiconductor devices as final control devices for a single load
• CPC Class Codes: Y02E 10/56 Power conversion systems, e.g. maximum power point trackers
• CPC Class Codes: Y10S 323/906 Solar cell systems

Abstract

A system for providing power from solar cells where each cell or cell array is allowed to produce its maximum available power and converted by its own DC/DC converter. In one form the system includes: one or more solar generators, each of which has at least one solar cell; a maximum power tracker operatively associated with each solar generator, where the maximum power tracker includes a buck type DC/DC converter without an output inductor, and the maximum power trackers of the solar generators are operatively connected in series with each other; and an inductor operatively connected to the series connected maximum power trackers.

Claims

1. A system for providing power from solar cells, comprising:

a plurality of solar generators, wherein each of said solar generators has at least one solar cell;

a plurality of series connected maximum power trackers, each of said maximum power trackers operatively associated with a corresponding solar generator of the plurality of solar generators, each of said maximum power trackers including a buck type DC/DC converter without an output inductor; and

an inductor operatively connected to the series connected maximum power trackers to provide electrical power to a load;

wherein each of said maximum power trackers is controlled to operate the corresponding solar generator at a maximum power point.

2. A system as claimed in claim 1, wherein each of the maximum power trackers includes an energy storage capacitor and a control means for adjusting the buck type DC/DC converter duty cycle to operate the corresponding solar generator at the maximum power point.

3. A system as claimed in claim 2, wherein said control means is to adjust a duty cycle of the buck type DC/DC converter to extract maximum power from the corresponding solar generator based on a voltage of the corresponding solar generator, a voltage of the energy storage capacitor, and a duration of switch off time of the buck type DC/DC converter.

4. A system as claimed in claim 1, wherein switching operations of the DC/DC converters of the maximum power trackers are synchronized in frequency via a synchronizing signal.

5. A system as claimed in claim 1, wherein each of the solar generators has a single solar cell.

6. A system as claimed in claim 1, wherein each of the solar generators includes at least one solar cell and each solar cell is connected to its own dedicated maximum power tracker so that the tracker responds to its connected solar cell.

7. A system as claimed in claim 1, wherein the inductor is a single inductor shared by the buck type DC/DC converters of the series connected maximum power trackers.

8. A system as claimed in claim 1, wherein the load includes devices that use or store the electrical power.

9. A system as claimed in claim 2, wherein the DC/DC converter has a switch;

and the energy storage capacitor is coupled between the corresponding solar generator and the switch of the DC/DC converter.

10. A system as claimed in claim 1, wherein switching operations of the DC/DC converters of the maximum power trackers are synchronized in frequency but have offsets in phase.