Charging in multiple voltage start/stop bas system

• US 9,163,600 B2
• Filed: 06/06/2013
• Issued: 10/20/2015
• Est. Priority Date: 06/06/2013
• Status: Active Grant

• Current Assignee: BorgWarner Incorporated
• Original Assignee: Remy Technologies LLC (BorgWarner Incorporated)
• Inventors: Neet, Kirk
• Primary Examiner(s): Patel, Tulsidas C
• Assistant Examiner(s): REID JR, CHARLES H
• Application Number:
  US13/911,462
• Publication Number:
  US 20140361536A1
• Time in Patent Office: 866 Days
• Field of Search: 290/31, 290/7, 290/16, 290/50, 318/139, 307/37, 307/71, 180/65.1, 180/65.245, 701/22, 903/903, 903/907, 903/960
• US Class Current: 1/1
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: F02N 11/04 the motors being associated with current generators
• CPC Class Codes: F02N 11/0866 comprising several power sources, e.g. battery and capacitor or two batteries
• CPC Class Codes: F02N 11/087 Details of the switching means in starting circuits, e.g. relays or electronic switches
• CPC Class Codes: F02N 2011/0874 characterised by said switch being an electronic switch
• CPC Class Codes: F02N 2011/0896 Inverters for electric machines, e.g. starter-generators
• CPC Class Codes: F02N 2200/041 Starter speed
• CPC Class Codes: F02N 2200/063 Battery voltage
• CPC Class Codes: H02J 7/0024 Parallel/serial switching of connection of batteries to charge or load circuit
• CPC Class Codes: H02J 7/1423 with multiple batteries
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

An alternator-starter system and method is disclosed. A method of operating an alternator-starter having an inverter/rectifier for starting an engine and charging a plurality of batteries includes providing two switches for each battery, monitoring voltages of each of the plurality of batteries, and switching the switches to selectively charge individual ones of the plurality of batteries. A system includes a plurality of batteries connected in series, and includes first and second switches for each battery, the first switch being operable to switchably connect the upper rail of the inverter/rectifier with the respective (+) terminal, the second switch being operable to switchably connect the lower rail of the inverter/rectifier with the respective (−) terminal. A high voltage configuration may be utilized for motoring and generating modes.

Claims

1. An alternator-starter system mechanically coupled with an engine, comprising:

a stator having three coils;

an inverter/rectifier having three nodes connected to respective ones of the stator coils, the inverter/rectifier having an upper rail and a lower rail defining a DC bus;

a plurality of batteries, each battery having a positive (+) terminal and a negative (−

) terminal;

first and second switches for each battery, the first switch being operable to switchably connect the upper rail with the respective (+) terminal, the second switch being operable to switchably connect the lower rail with the respective (−

) terminal; and

a controller operable to monitor voltages of each battery and operably coupled with the first and second switches for each battery wherein the controller selectively operates the alternator-starter system in a generating mode wherein the plurality of batteries are charged or a motoring mode wherein the alternator-starter system generates a mechanical torque and wherein when the alternator-starter system supplies a torque to the engine to start the engine in the motoring mode, the plurality of batteries are connected in series; and

wherein when the controller operates the alternator-starter system in the generating mode, the controller is adapted to selectively charge individual ones of the plurality of batteries.

2. The system of claim 1, wherein when the monitored voltage of any one of the plurality of batteries is below a corresponding threshold voltage, the controller closes the one battery'"'"'s first and second switches to charge such battery.

3. The system of claim 2, wherein the controller is operable to close the first switch of a series-beginning battery of the plurality of batteries and the second switch of a series-end battery of the plurality of batteries to supply a summed voltage of such series of batteries across the DC bus.

4. The system of claim 3, wherein the controller is operable to determine that the alternator-starter is operating in generating mode at a rotational speed higher than a certain rpm.

5. The system of claim 1, wherein the batteries comprise a first battery (B1) and a second battery (B2), wherein when the monitored voltage of battery B1 is below a first voltage, the controller closes the first B1 switch (D) and the second B1 switch (B) to charge battery B1, and wherein when the monitored voltage of battery B2 is below a second voltage the controller closes the first B2 switch (C) and the second B2 switch (A) to charge battery B2.

6. The system of claim 5, wherein the controller is operable to close switches A and D to supply a summed voltage of batteries B1 and B2 across the DC bus.

7. The system of claim 1, wherein when the controller determines that a battery of the plurality of batteries is broken, the controller opens at least one of the first and second switches corresponding to such broken battery.

8. The system of claim 1, wherein the controller is further operable to monitor battery temperature for each of the plurality of batteries.

9. A method of operating an alternator-starter for starting an engine and charging a plurality of batteries, the alternator-starter having an inverter/rectifier, the method comprising:

providing two switches for each battery;

monitoring voltages of each of the plurality of batteries;

switching the switches to selectively charge individual ones of the plurality of batteries when the alternator-starter is operated in a generating mode; and

connecting the plurality of batteries in series to supply electrical power to the alternator-starter when operating the alternator-starter in a motoring mode and supplying mechanical torque to the engine to start engine.

10. The method of claim 9, wherein when the monitored voltage of any one of the plurality of batteries is below a corresponding threshold voltage, closing the one battery'"'"'s switches to connect such battery to the inverter/rectifier and thereby charge the battery.

11. A method of operating an alternator-starter having a stator with at least three coils, an inverter/rectifier having at least three nodes being connected to respective ones of the stator coils, the inverter/rectifier having an upper rail and a lower rail defining a DC bus, the method comprising:

mechanically coupling the alternator-starter with an engine;

providing a plurality of batteries, each battery having a positive (+) terminal and a negative (−

) terminal;

providing first and second switches for each battery, the first switch being operable to switchably connect the upper rail with the respective (+) terminal, the second switch being operable to switchably connect the lower rail with the respective (−

) terminal;

monitoring voltages of each battery;

periodically charging the plurality of batteries with the alternator-starter wherein the switches are operable to charge the batteries in different configurations and the switches are operated to charge the plurality of batteries in series only when a rotational speed of a rotor of the alternator-starter exceeds a predetermined speed; and

operating the switches to connect the plurality of batteries in series to supply electrical power to the alternator-starter when using the alternator-starter to supply torque to the engine to start the engine.

12. The method of claim 11, wherein when the monitored voltage of any one of the plurality of batteries is below a corresponding threshold voltage, closing the one battery'"'"'s first and second switches to charge such battery.

13. The method of claim 11, further comprising closing the first switch of a series-beginning battery of the plurality of batteries and closing the second switch of a series-end battery of the plurality of batteries to thereby provide a summed voltage of such series of batteries across the DC bus.

14. The method of claim 13, further comprising determining when the rotational speed of the rotor of the alternator-starter exceeds the predetermined speed and, if so, providing the summed voltage across the DC bus, to thereby charge the series of batteries.

15. The method of claim 14, further comprising determining which batteries of the plurality of batteries to include in the series of batteries based on the rotational speed.

16. The method of claim 11, further comprising monitoring the temperatures of respective ones of the plurality of batteries.

17. The method of claim 16, further comprising defining a series voltage charging target for the series-connected batteries based on the monitored battery temperatures.

18. The method of claim 13, further comprising, in motoring mode of the alternator-starter, determining when rotational speed of a rotor of the alternator-starter exceeds a predetermined speed and, if so, reducing the summed voltage across the DC bus.