Device for generating electrical energy for a power supply bus

• US 6,181,115 B1
• Filed: 10/22/1999
• Issued: 01/30/2001
• Est. Priority Date: 10/23/1998
• Status: Expired due to Term

• Current Assignee: Agence Spatiale Europeenne
• Original Assignee: Agence Spatiale Europeenne
• Inventors: Olsson, Dan, Perol, Philippe Alfred, Haines, James Edward
• Primary Examiner(s): Wong, Peter S.
• Assistant Examiner(s): Vu, Bao Q.
• Application Number:
  US09/422,972
• Time in Patent Office: 466 Days
• Field of Search: 323/906, 323/234, 320/101, 320/117, 320/118, 136/293
• US Class Current: 323/234
• CPC Class Codes: B64G 1/1007 Communications satellites
• CPC Class Codes: B64G 1/1085 Swarms and constellations
• CPC Class Codes: B64G 1/428 Power distribution and management
• CPC Class Codes: B64G 1/443 Photovoltaic cell arrays
• CPC Class Codes: H01M 10/44 Methods for charging or discharging circuits for charging H02J7/00
• CPC Class Codes: H01M 10/465 with solar battery as charging system
• CPC Class Codes: H02J 7/35 with light sensitive cells
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y10S 323/909 Remote sensing

Abstract

A device for generating electrical energy for a power supply bus connected to a load. The device includes an electrical energy storage unit having at least one battery, a solar energy generator presenting a plurality of modules, a regulator for controlling discharging of the storage unit to power the bus, and for each module, a three-state control device. The device also includes a control unit causing the control devices to take up one of their three states. Each three-state control device has a first state in which current from the module powers the bus, a second state in which current from module powers the storage unit, and a third state in which the module is short-circuited.

Claims

1. A device for generating electrical energy for a power supply bus connected to a load, and comprising:

a) an electrical energy storage unit comprising at least one battery;

b) a solar energy generator presenting a plurality of modules;

c) a regulator for controlling discharging of the storage unit to power said bus from the storage unit, the device including;

d) for each module, a three-state control device presenting;

i) a first state in which the current from said module powers the bus;

ii) a second state in which the current from said module powers the storage unit; and

iii) a third state in which said module is short circuited; and

e) a control unit for causing the control devices to take up one of their three states.

2. A device according to claim 1, wherein each module is a section constituted by a plurality of elementary generators.

3. A device according to claim 1, wherein the power supply bus has a capacitive element.

4. A device according to claim 1, wherein the control unit has a control state for subdividing the modules amongst at least one of two groups, namely:

i) a first group in which at least one module is in its first state to power the bus, and in which one of the modules is allocated to regulating the bus voltage, and is for this purpose in its first state only while the maintenance of a nominal voltage on the bus requires current to be delivered from said module; and

ii) a second group in which at least one module is either in its second state, or else in its third state, as a function of a desired level of charging current, the number of modules in the second state being a function of the desired charging current value.

5. A device according to claim 4, wherein said module allocated to said regulation is in its third state when maintaining the nominal voltage of the bus does not require current to be contributed from said module.

6. A device according to claim 4, wherein, when maintaining the nominal voltage of the bus does not require current to be contributed from said module allocated to said regulation, said module is placed in its second state if that is possible given said desired level of charging current, and otherwise it is put in its third state.

7. A device according to claim 4, including a charging current control device which generates said desired value for the charging current of the electrical energy storage unit.

8. A device according to claim 4, wherein the control device has an outlet for an end-of-charge logic signal to place at least one of the modules forming a portion of the second group in its third state.

9. A device according to claim 1, wherein each module is connected to the bus via a first forwardly-conductive diode, and to the electrical energy storage unit via a controlled switch, and a second forwardly-conductive diode, closure of the controlled switch placing the module in its second state.

10. The use of a device according to claim 1, in a system for which the end-of-charge voltage of the storage unit is significantly lower than the nominal voltage of the bus.

11. A method for generating electrical energy for a power supply bus coupled to a load, an electrical energy storage unit, a regulator, and a solar energy generator, wherein the electrical energy storage unit comprises at least one battery, the regulator controls discharging of the storage unit to power said bus from the storage unit, and the solar energy generator presents a plurality of modules and associated with each module is a three-state control device, the method comprising:

a) controlling at least a first one of the three-state control devices to be in a first state in which the current from the module associated with the first one of the three-state control device powers the bus;

b) controlling at least a second one of the three-state control devices to be in a second state in which the current from the module associated with the second one of the three-state control devices powers the storage unit; and

c) controlling at least a third one of the three-state control devices to be in a third state in which the module associated with the third one of the three-state control devices is short circuited.

12. The method according to claim 11, wherein the first, second and third ones of the plurality of three-state control devices are individually controlled.

13. The method according to claim 11, wherein the first, second and third ones of the plurality of three-state control devices are the same three-state control device.

14. The method according to claim 11, wherein the first one of the plurality of three-state control devices is controlled to be in the first state when the battery is not fully charged and the bus voltage is greater than a reference voltage.

15. The method according to claim 11, wherein the second one of the plurality of three-state control devices is controlled to be in the second state when the battery is not fully charged and the bus voltage is less than a reference voltage.

16. The method according to claim 11, wherein the third one of the plurality of three-state control devices is controlled to be in the third state when the battery is fully charged.