Method for charging a storage element of an autonomous system

• US 20080278118A1
• Filed: 04/30/2008
• Published: 11/13/2008
• Est. Priority Date: 05/11/2007
• Status: Active Grant

• Current Assignee: Commissariat a L'Energie Atomique (AES Corporation)
• Original Assignee: Commissariat a L'Energie Atomique (AES Corporation)
• Inventors: Labrunie, Antoine, Perichon, Pierre
• Granted Patent: US 7,944,179 B2
• Time in Patent Office: Days
• US Class Current: 320/155
• CPC Class Codes: H02J 7/1415 with a generator driven by a prime mover other than the motor of a vehicle
• CPC Class Codes: H02J 7/34 Parallel operation in networks using both storage and other dc sources, e.g. providing buffering H02J7/14 takes precedence

Abstract

The charging method comprises limiting, according to the temperature, of the power supplied to the storage element to a charging setpoint power. The energy required to charge the storage element is determined and the period during which the power resource will be available is estimated. A theoretical mean power is calculated by means of these two items of information. The progressions of the temperature and of a maximum acceptable power are estimated. A maximum energy able to be delivered by the generator is calculated from the maximum acceptable power. The value of the charging setpoint power is defined by comparison of the required energy with the maximum energy and by comparison of the mean power with the maximum acceptable power.

Claims

1. A method for charging a power storage element of an autonomous system comprising electronic components from a generator, with limiting, according to the temperature, of the power supplied to the storage element to a charging setpoint power, method comprising

estimating the time period during which the power resource available to the generator is, up to a preset moment, greater than a preset threshold value,

estimating the temperature progression up to said moment,

estimating the progression of a maximum acceptable power up to said moment, according to the temperature progression and to data representative of the reliability of the system according to the temperature,

determining the energy required to charge the storage element,

calculating, according to the energy required and to said time period, of a theoretical mean power spread over said time period to come, to be delivered to the storage element to charge the latter completely,

estimating from the maximum acceptable power of a maximum energy during the time period to come able to be delivered by the generator,

determining a charging setpoint power according to the comparison between the required energy and the maximum energy and to the comparison between the mean power and the maximum charging power.

2. The method according to claim 1, wherein the value of the charging setpoint power is equal to the mean power if the required energy is less than or equal to the maximum energy and if the mean power is less than the maximum acceptable power, the value of the charging setpoint power being equal to the maximum acceptable power in the other cases.

3. The method according to claim 1, wherein the value of the charging setpoint power is equal to the mean power if the required energy is less than or equal to the maximum energy and if the mean power is less than the minimum of the maximum acceptable power estimated for the forthcoming period, the value of the charging setpoint power being equal to the maximum acceptable power in the other cases.

4. The method according to claim 1, comprising determination of a maximum acceptable state of charge of the storage element according to the temperature, the required energy being the power required to charge the storage element to the maximum state of charge.

5. The method according to claim 1, wherein the required energy is the power required to charge the storage element completely.

6. The method according to claim 1, wherein temperature measurement comprises measurement of the ambient temperature.

7. The method according to claim 1, wherein temperature measurement comprises a measurement representative of the temperature of the electronic components.

8. The method according to claim 1, wherein the generator being a photovoltaic generator, the period during which the power resource is available represents the period of sunlight.

9. The method according to claim 1, wherein the generator being a micro-hydraulic generator, said period represents the time during which the hydraulic flowrate is greater than a preset threshold.

10. The method according to claim 1, wherein power production by means of the generator being intermittent and quasi-periodic, the autonomous system comprises recording of its operating conditions over a predetermined number of periods.

11. The method according to claim 10, wherein the maximum energy is determined taking the operating conditions over a predetermined number of immediately preceding periods into account.

12. The method according to claim 10, wherein the recorded operating conditions comprise the temperature, the effective operating time of the generator and/or the progression of the required power.

13. The method according to claim 1, wherein the data representative of reliability comprises at least data relating to reliability of the electronic components and of the storage element.

14. The method according to claim 13, wherein the data representative of the reliability of the system is represented by the mean time between failures.

15. The method according to claim 13, wherein the data representative of the reliability of the system is represented by a plurality of curves defining the maximum acceptable power versus temperature, for a given reliability criterion.

16. The method according to claim 1, wherein the charging setpoint power is equal to the mean power and a corrective factor, the setpoint power being lower than the maximum power.