Method and apparatus for adjusting wakeup time in electrical power converter systems and transformer isolation

• US 20050018454A1
• Filed: 05/12/2004
• Published: 01/27/2005
• Est. Priority Date: 05/12/2003
• Status: Active Grant

• Current Assignee: Rhombus Energy Solutions, Inc. (BorgWarner Incorporated)
• Original Assignee: Ballard Power Systems Corporation (Siemens AG)
• Inventors: Harmon, Kent M., Deng, Duo, Tuladhar, Anil
• Granted Patent: US 7,269,036 B2
• Time in Patent Office: Days
• US Class Current: 363/49
• CPC Class Codes: H02J 2300/20 The dispersed energy generation being of renewable origin
• CPC Class Codes: H02J 2300/24 of photovoltaic origin
• CPC Class Codes: H02J 2300/26 involving maximum power point tracking control for photovoltaic sources
• CPC Class Codes: H02J 2300/30 The power source being a fuel cell
• CPC Class Codes: H02J 3/381 Dispersed generators
• CPC Class Codes: H02J 3/466 Scheduling the operation of the generators, e.g. connecting or disconnecting generators to meet a given demand
• CPC Class Codes: H02J 7/35 with light sensitive cells
• CPC Class Codes: Y02B 10/10 Photovoltaic [PV]
• CPC Class Codes: Y02E 10/56 Power conversion systems, e.g. maximum power point trackers
• CPC Class Codes: Y10S 323/901 Starting circuits
• CPC Class Codes: Y10S 323/906 Solar cell systems

Abstract

An electrical power converter system adjusts a wakeup voltage periodically, to permit earlier connection and/or operation, to increase performance. The electrical power converter system selects between a mathematically adjusted wakeup voltage based on at least one previous period, and a table derived wakeup voltage that takes into account historical information. The electrical power converter system is particularly suited to applications with periodicity such as solar based photovoltaic power generation.

Claims

1. A method of operating an electrical power converter system to transform power for a power source, the method comprising:

determining an amount of power available from a power source at approximately a startup time; and

adjusting a value of a wakeup voltage parameter of the electrical power converter system from a value of the wakeup voltage parameter of the electrical power converter system for a previous period based at least in part on the determined amount of power available from the power source at approximately the startup time.

2. The method of claim 1 wherein adjusting a value of a wakeup voltage parameter of the electrical power converter system from a value of the wakeup voltage parameter of the electrical power converter system from a previous period based at least in part on the determined amount of power available from the power source at approximately the startup time comprises increasing the value of the wakeup voltage parameter if the amount of power available from the power source at approximately the startup time is less than a startup power threshold.

3. The method of claim 1 wherein adjusting a value of a wakeup voltage parameter of the electrical power converter system from a value of the wakeup voltage parameter of the electrical power converter system from a previous period based at least in part on the determined amount of power available from the power source at approximately the startup time comprises decreasing the value of the wakeup voltage parameter if the amount of power available from the power source at approximately the startup time is greater than a startup power threshold.

4. The method of claim 1 wherein adjusting a value of a wakeup voltage parameter of the electrical power converter system from a value of the wakeup voltage parameter of the electrical power converter system from a previous period based at least in part on the determined amount of power available from the power source at approximately the startup time comprises calculating the value of the wakeup voltage parameter in real time based on the amount of power available from the power source at approximately the startup time relative to a startup power threshold, and further comprising:

selecting between the value of the wakeup voltage parameter calculated in real time and a value of the wakeup voltage parameter stored in a historically based lookup table, wherein the value of the wakeup voltage parameter from the historically based lookup table is based at least in part on a real time clock.

5. The method of claim 1, further comprising:

determining that the determined amount of power available from the power source at approximately the startup time remains below a startup power threshold for a defined period of time before adjusting the value of a wakeup voltage parameter of the electrical power converter system.

6. The method of claim 1, further comprising:

electrically coupling a transformer of the electrical power converter system to a power grid when a voltage available from the power source exceeds the value of the wakeup voltage parameter.

7. The method of claim 1, further comprising:

operating a main inverter of the electrical power converter system to supply AC power to a power grid when a voltage available from the power source exceeds the value of the wakeup voltage parameter.

8. The method of claim 1 wherein the previous period is one day.

9. The method of claim 1 wherein the previous period is a day immediately previous to a current day.

10. The method of claim 1 wherein the previous period is greater than one day.

11. The method of claim 1, further comprising:

receiving a start command; and

enabling a maximum power point tracking algorithm after receiving the start command, wherein the startup time occurs a first defined period of time after enabling the maximum power point tracking algorithm, allowing some transients, if any, to settle.

12. A method of operating an electrical power converter system to transform power from a power source, the method comprising:

selecting between a value of a wakeup voltage parameter calculated in real time and a value of the wakeup voltage parameter stored in a historically based lookup table, wherein the value of the wakeup voltage parameter from the historically based lookup table is based at least in part on a real world time;

determining a voltage available from the power source;

determining if the determined voltage available from the power source exceeds the selected value of the wakeup voltage parameter;

if the determined voltage available from the power source exceeds the selected value of the wakeup voltage parameter,

determining a power available from the power source;

determining if the power available from the power source is less than a startup power threshold;

providing power to a load if the power available from the power source is not less than the startup power threshold; and

calculating a value of the wakeup voltage parameter based on the power available from the power source with respect to the startup power threshold.

13. The method of claim 12, further comprising:

enabling a maximum power point tracking algorithm in response to determining that the determined voltage available from the power source exceeds the selected value of the wakeup voltage parameter.

14. The method of claim 12, further comprising:

waiting a first defined period of time after enabling the maximum power point tracking algorithm to allow some transients, if any, to settle before determining the power available from the power source.

15. The method of claim 12, further comprising:

determining that the determined power available from the power source remains below the startup power threshold for a defined period of time before calculating the value of the wakeup voltage parameter.

16. The method of claim 12, further comprising:

entering a sleep operating state without providing power to a load if the determined voltage available from the power source does not exceed the selected value of the wakeup voltage parameter.

17. The method of claim 16, further comprising:

decoupling a transformer of the electrical power converter system from a grid when entering the sleep operating state of the electrical power converter system.

18. The method of claim 12 wherein selecting between a value of a wakeup voltage parameter calculated in real time and a value of the wakeup voltage parameter stored in a historically based lookup table, wherein the value of the wakeup voltage parameter from the historically based lookup table is based at least in part on a real world time, comprises:

determining a real time;

determining an operating state of the electrical power converter system;

selecting the wakeup voltage parameter stored in the historically based lookup table if both the operating state is a sleep state and the real time is at least equal to a wakeup time.

19. An electrical power converter system, comprising:

at least a first switch operable between an ON state and an OFF state; and

a controller coupled to control the at least first switch, and configured to determine an amount of power available from a power source at approximately a startup time; and

adjust a value of a wakeup voltage parameter of the electrical power converter system from a value of the wakeup voltage parameter of the electrical power converter system for a previous period based at least in part on the determined amount of power available from the power source at approximately the startup time.

20. The electrical power converter system of claim 19 wherein the controller is configured to adjust the value of the wakeup voltage parameter of the electrical power converter system from the value of the wakeup voltage parameter from the previous period based at least in part on the determined amount of power available from the power source at approximately the startup time by increasing the value of the wakeup voltage parameter if the amount of power available from the power source at approximately the startup time is less than a startup power threshold.

21. The electrical power converter system of claim 19 wherein the controller is configured to adjust the value of the wakeup voltage parameter of the electrical power converter system from the value of the wakeup voltage parameter from the previous period based at least in part on the determined amount of power available from the power source at approximately the startup time by decreasing the value of the wakeup voltage parameter if the amount of power available from the power source at approximately the startup time is greater than a startup power threshold.

22. The electrical power converter system of claim 19 wherein the controller is configured to select between a value of the wakeup voltage parameter calculated in real time and a value of the wakeup voltage parameter stored in a historically based lookup table, wherein the value of the wakeup voltage parameter from the historically based lookup table is based at least in part on a real world time.

23. The electrical power converter system of claim 19, further comprising:

a transformer, the controller configured to electrically couple the transformer of the electrical power converter system to a power grid when a voltage available from the power source exceeds the value of the wakeup voltage parameter.

24. The method of claim 19, further comprising:

a main inverter, the controller configured to operate the main inverter of the electrical power converter system to supply AC power to a power grid when a voltage available from the power source exceeds the value of the wakeup voltage parameter.

25. An electrical power converter system, comprising:

an input bus;

an output bus;

at least one switch electrically coupled between the input and the output buses; and

a controller coupled to control the at least one switch, the controller configured to select between a value of a wakeup voltage parameter calculated in real time and a value of the wakeup voltage parameter stored in a historically based lookup table, wherein the value of the wakeup voltage parameter from the historically based lookup table is based at least in part on a real world time.

26. The electrical power converter system of claim 25 wherein the controller is configured to select the value of the wakeup voltage parameter stored in the historically based lookup table if both an operating state of the electrical power converter system is a sleep state and a real time is at least equal to a wakeup time.

27. The electrical power converter system of claim 26 wherein the controller is configured to determine if a voltage available from the power source exceeds the selected value of the wakeup voltage parameter;

if the determined voltage available from the power source exceeds the selected value of the wakeup voltage parameter, provide power to a load if a power available from the power source is not less than a startup power threshold; and

calculate a value of the wakeup voltage parameter based on the power available from the power source relative to the startup power threshold.

28. The electrical power converter system of claim 26 wherein the controller is configured to execute a maximum power point tracking algorithm in response to determining that a voltage available from the power source exceeds the selected value of the wakeup voltage parameter.

29. The electrical power converter system of claim 28 wherein the controller is configured to place the electrical power converter system into a sleep operating state without providing power to a load if the voltage available from the power source does not exceed the selected value of the wakeup voltage parameter.