Method of finding a maximum power of a photovoltaic generator

• US 20070027644A1
• Filed: 07/11/2006
• Published: 02/01/2007
• Est. Priority Date: 07/14/2005
• Status: Active Grant

• Current Assignee: SMA Solar Technology AG
• Original Assignee: SMA Solar Technology AG
• Inventors: Laschinski, Joachim, Arend, Oliver, Bettenwort, Gerd, Leonhardt, Gerald, Kuhnel, Christian, Reichenbacher, Wolfgang
• Granted Patent: US 7,471,073 B2
• Time in Patent Office: Days
• US Class Current: 702/60
• CPC Class Codes: G05F 1/67 to the maximum power available from a generator, e.g. from solar cell
• 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 method of finding a power maximum of a photovoltaic generator using an MPP regulator of a photovoltaic current converter by means of which a maximum generator power is set at an operating point of the generator'"'"'s characteristic curve is intended to supply improved efficiency when the generator is partially shadowed. This is achieved by switching the MPP regulator off in order to next load and/or unload the generator to allow a new operating point of the generator'"'"'s characteristic curve to set and by next switching the MPP regulator on again.

Claims

1. A method of finding a power maximum of a photovoltaic generator, using an MPP regulator of a current converter by means of which a maximum generator power is set at an operating point of the generator'"'"'s characteristic curve,

wherein the MPP regulator is switched off in order to then load and/or unload the generator and that the MPP regulator is next switched on again in order to bring the operating point of the generator'"'"'s characteristic curve from a stable condition into an instable condition and vice versa.

2. The method as set forth in claim 1,

wherein after the MPP regulator has been switched off, the power of the current converter is increased so that a first operating point of a power characteristic curve, which corresponds to a local maximum, moves toward a second operating point located between the first operating point and a third operating point and near said third operating point, said third operating point being a global maximum.

3. The method as set forth in claim 1,

wherein after the MPP regulator has been switched off, the power of the current converter is increased so that a first operating point of a power characteristic curve, which corresponds to a global maximum, moves toward a second operating point located near point zero of the characteristic curve.

4. The method as set forth in claim 3,

wherein the generator is unloaded again when the voltage falls below a limit.

5. The method as set forth in claim 1,

wherein after the MPP regulator has been switched off, the power of the current converter is reduced so that a first operating point of a power characteristic curve, which corresponds to a local maximum, moves toward a second operating point located near the generator'"'"'s idle voltage.

6. The method as set forth in claim 1,

wherein after the MPP regulator has been switched off, the power of the current converter is reduced so that a first operating point of a power characteristic curve, which corresponds to a local maximum, moves toward a second operating point located near the generator'"'"'s idle voltage, a third operating point occurring after the current has been increased, said third operating point being as high as the first operating point and near a fourth operating point, which is a global maximum.

7. The method as set forth in claim 1,

wherein the generator voltage is stored.