System and Method for Local String Management Unit

• US 20130026843A1
• Filed: 09/26/2012
• Published: 01/31/2013
• Est. Priority Date: 08/21/2009
• Status: Active Grant

• Current Assignee: Tigo Energy, Inc
• Original Assignee: Tigo Energy, Inc
• Inventors: Arditi, Shmuel, AVRUTSKY, Mordechay, Hadar, Ron, Makhota, Maxym
• Granted Patent: US 8,686,333 B2
• Time in Patent Office: Days
• US Class Current: 307/82
• CPC Class Codes: H02J 1/102 being switching converters H02J1/108, H02J1/12 take precedence
• CPC Class Codes: H02J 2300/26 involving maximum power point tracking control for photovoltaic sources maximum power point systems in particular G05F1/67
• CPC Class Codes: H02J 2310/18 The network being internal to a power source or plant
• CPC Class Codes: H02J 3/381 Dispersed generators
• CPC Class Codes: H02J 3/46 Controlling of the sharing of output between the generators, converters, or transformers
• CPC Class Codes: Y02E 10/56 Power conversion systems, e.g. maximum power point trackers

Abstract

Apparatuses and methods include a solar array having one or more strings of series-connected local management units (LMUs). Each LMU is parallel-connected to one of a plurality of solar modules. The strings are connected in parallel via a parallel bus. Local string management units (LSMUs) can increase or decrease an output voltage of the solar array by upconverting or downconverting string output voltages from each string. LSMUs can also operate in a bypass mode to increase overall power output.

Claims

1. A local string management unit (LSMU) comprising:

an input configured to receive an input voltage from a string;

a voltage conversion portion connected to the input and configured to;

convert the input voltage to a target voltage; and

operate in a bypass mode; and

an output connected to the voltage conversion portion and configured to provide the target voltage to a load.

2. The LSMU of claim 1, wherein:

the voltage conversion portion operates in the bypass mode when the input voltage is within a range from the output voltage of a strongest string; and

the voltage conversion portion converts the input voltage to the target voltage when the input voltage is not within the range from the output voltage of the strongest string.

3. The LSMU of claim 1, wherein the LSMU resides in a combiner box and connects to other LSMUs via the combiner box.

4. The LSMU of claim 1, wherein a switchable connection reroutes current through a low-loss conductive path.

5. A computer-implemented method comprising:

selecting, via a computing device, a target voltage;

operating, via a computing device, a first local string management unit (LSMU) in a bypass mode, wherein the first LSMU is connected to a first string in a solar array, wherein the first string has a first string output voltage within a range from the output voltage of a strongest string in the solar array; and

instructing, via a computing device, a second LSMU to upconvert a second string output voltage for a second string in the solar array not having a string output voltage within the range from the output voltage of the strongest string in the solar array, so that a solar array output voltage equals the target voltage, and wherein the second LSMU is connected to the second string.

6. The computer-implemented method of claim 5, further comprising determining, via a computing device, if disconnecting the second string from a parallel bus of the solar array causes an increase in solar array output power.

7. The computer-implemented method of claim 5, further comprising:

determining, via a computing device, a maximum power point for the first string; and

operating, via a computing device, the first string at the maximum power point.

8. The computer-implemented method of claim 5, wherein the instructing is performed by a management unit in communication with the first LSMU and the second LSMU.