METHOD AND APPARATUS FOR TRACKING MAXIMUM POWER POINT

• US 20120091968A1
• Filed: 07/20/2011
• Published: 04/19/2012
• Est. Priority Date: 10/18/2010
• Status: Abandoned Application

• Current Assignee: Electronics and Telecommunications Research Institute
• Original Assignee: Electronics and Telecommunications Research Institute
• Inventors: Yang, Yil Suk, Kim, Jongdae, HEO, Sewan
• Application Number:
  US13/186,896
• Publication Number:
  US 20120091968A1
• Time in Patent Office: Days
• US Class Current: 320/138
• CPC Class Codes: H02J 7/35 with light sensitive cells
• CPC Class Codes: Y02E 10/56 Power conversion systems, e.g. maximum power point trackers

Abstract

Disclosed are a method and an apparatus for tracking a maximum power point. An apparatus for tracking a maximum power point according to an exemplary embodiment of the present disclosure includes: a system controller monitoring a plurality of energy sources for each predetermined period and selecting an energy source having a maximum power among the plurality of energy sources; and a maximum power tracking unit limiting an output voltage of the selected energy source to a reference voltage determined by an open circuit voltage of the selected energy source to track the maximum power point from the selected energy source and store the power of the selected energy source in a battery.

Claims

1. An apparatus for tracking a maximum power point, comprising:

a system controller configured to monitor a plurality of energy sources for each predetermined period, and select an energy source having a maximum power among the plurality of energy sources; and

a maximum power tracking unit configured to limit an output voltage of the selected energy source to a reference voltage determined by an open circuit voltage of the selected energy source, in order to track the maximum power point from the selected energy source and store the power of the selected energy source in a battery.

2. The apparatus of claim 1, wherein the system controller includes:

a power detector configured to measure the open circuit voltage of each energy source and detect the power of each energy source;

a microprocessor configured to set a reference voltage having a maximum power for each energy source using the open circuit voltage of each energy source measured by the power detector, and to confirm an energy source having the maximum power among the plurality of energy sources based on the power of each energy source detected by the power detector;

an input selector configured to select the energy source by controlling a switch unit including a plurality of switches corresponding to the plurality of energy sources by instructions from the microprocessor;

a voltage output unit outputting the reference voltage of the selected energy source to the maximum power tracking unit; and

a charging state determining unit confirming the charging state of the battery.

3. The apparatus of claim 2, wherein the power detector detects power of each energy source by measuring the open circuit voltage that is a voltage generated when an output voltage of each energy source rises to a threshold in a state where the switch unit is switched-off, and measuring voltage and current generated from the maximum power tracking unit according to the reference voltage in a state where the switch unit is switched-on.

4. The apparatus of claim 2, further comprising a power supplier configured to supply the power stored in the battery to the load according to the voltage of the load when the voltage of the battery is different from the voltage of the load.

5. The apparatus of claim 4, wherein the microprocessor divides the operation period of the apparatus for tracking a maximum power point into three types of periods including a system operation period, a load operation period, and a low power charging period,

the microprocessor maintains the system controller and the maximum power tracking unit as an operation mode, the power supplier as the low power operation mode, and the load as the non-operation mode, in the system operation period,

the microprocessor keeps the microprocessor, the power supplier, and the load as the operation mode, the input selector as the low power operation mode, and the power detector and the charging state determining unit as the non-operation mode, in the load operation period, and

the microprocessor keeps the input selector and the power supplier as the low power operation mode, and the power detector, the microprocessor, the charging state determining unit, and the load as the non-operation mode, in the lower power charging period.

6. The apparatus of claim 5, wherein the microprocessor controls the time and frequency of the system operation period and the load operation period, according to the charging state of the battery.

7. The apparatus of claim 2, wherein the microprocessor changes the predetermined period, according to the charging state of the battery.

8. The apparatus of claim 2, wherein the microprocessor determines whether or not the load is operated, operation contents, an operation timing, and an operation time of the load, according to the charging state of the battery.

9. The apparatus of claim 2, wherein the microprocessor disconnects the selected energy source, according to the charging state of the battery.

10. The apparatus of claim 2, wherein the charging state determining unit incorporates a communication module communicating with a communication module embedded in the battery to receive information indicating the charging state from the battery, and confirm the charging state of the battery.

11. The apparatus of claim 2, wherein the charging state determining unit measures the voltage of the battery to confirm the charging state of the battery.

12. A method for tracking a maximum power point, comprising:

confirming a charging state of a battery;

selecting an energy source having a maximum power among a plurality of energy sources when the charging state of the battery remains in an insufficient state of charge;

tracking a maximum power point from the selected energy source by limiting an output voltage of the selected energy source to a reference voltage determined by an open circuit voltage of the selected energy source; and

storing the power of the selected energy source in the battery.

13. The method of claim 12, wherein the selecting of the energy source includes:

detecting the open circuit voltage of each energy source;

setting a reference voltage having the maximum power for each energy source using the detected open circuit voltage;

measuring the power of each energy source in the set reference voltage; and

selecting an energy source having the maximum power among the plurality of energy sources according the measured results.

14. The method of claim 12, further comprising operating the load when the charging state of the battery remains in an excessive state or a normal state, after the confirming of the charging state.

15. The method of claim 12, further comprising:

determining whether or not one (1) period ends,

wherein if it is determined that the one (1) period ends, the method returns to the confirming of the charging state.