For hybrid super-capacitor / battery systems in pulsed power applications

• US 9,882,380 B2
• Filed: 05/16/2014
• Issued: 01/30/2018
• Est. Priority Date: 05/17/2013
• Status: Active Grant

• Current Assignee: Electro Standards Laboratories
• Original Assignee: Electro Standards Laboratories
• Inventors: Sepe, Jr., Raymond B, Steyerl, Anton, Bastien, Steven
• Primary Examiner(s): BARNIE, REXFORD N
• Assistant Examiner(s): Mourad, Rasem
• Application Number:
  US14/279,687
• Publication Number:
  US 20140339902A1
• Time in Patent Office: 1,355 Days
• CPC Class Codes: H02J 1/102 being switching converters H02J1/108, H02J1/12 take precedence
• CPC Class Codes: H02J 7/345 using capacitors as storage or buffering devices
• CPC Class Codes: H02M 1/0022 the disturbance parameters being input voltage fluctuations
• CPC Class Codes: H02M 1/0025 Arrangements for modifying reference values, feedback values or error values in the control loop of a converter
• CPC Class Codes: H02M 3/1566 with means for compensating against rapid load changes, e.g. with auxiliary current source, with dual mode control or with inductance variation
• CPC Class Codes: H02M 3/157 with digital control
• CPC Class Codes: H02M 3/158 including plural semiconductor devices as final control devices for a single load
• CPC Class Codes: H02M 3/1584 with a plurality of power processing stages connected in parallel

Abstract

A hybrid super-capacitor/battery system is disclosed (particularly under high pulsed power and low temperature conditions) which allows an existing battery system to ride through transient loading and provide excellent energy density and power density under practical loading conditions.

Claims

1. A system comprising:

a hybrid super-capacitor/battery system comprising a super-capacitor unit comprising one or more super-capacitors and a battery unit connected to a load, said battery unit comprising one or more battery cells rated at a battery output voltage;

a DC/DC converter connected to said super-capacitor unit and said battery unit, said DC/DC converter allowing charging and discharging of said super-capacitors; and

a power control system configured to reduce stresses and energy losses in said battery unit and provide improved charge-capacity and energy capacity, said power control system connected to said DC/DC converter, said power control system comprising an inner voltage control loop comprising a voltage controller and an outer current control loop comprising a current controller, said inner voltage control loop providing control of a load voltage to maintain a value of said load voltage within a predetermined range and regulating said value of load voltage to equal the battery output voltage, said outer current control loop providing said value to said inner voltage control loop and controlling a current of said battery unit to a predetermined set-point based on required operating conditions, said set point allowing output of said battery unit to be load-leveled and to allow said super-capacitor unit to provide a pulsed power needed by said load.

2. The system of claim 1, wherein said set-point is a constant value.

3. The system of claim 1, wherein said set-point comprises a set of values comprising a high set point value and a low set point value, where said power control system configured to not allow said super-capacitors to power said load unless a load current is above said high set-point value, and said power control system configured to not allow said super-capacitors to be recharged until said load current is below said low set-point value.

4. The system of claim 1, wherein said voltage controller is implemented using a proportional-integral (PI) controller.

5. The system of claim 1, wherein said current controller is implemented using a proportional-integral (PI) controller.

6. The system of claim 1, wherein said system comprises a switch controller having a pulse width modulation (PWM) generator that receives from said voltage controller a duty cycle, D[n], where D[n] is used by said PWM generator to generate a switch control signal, s(t), where s(t) is used by said PWM generator to drive a plurality of switches in order to control a system duty cycle, where driving said switches to increasing said system duty cycle results in a buck operation configured to charge said super-capacitors, and where driving said switches to decrease said system duty cycle results in a boost operation configured to relieve load of said battery unit.

7. The system of claim 6, wherein said duty cycle D[n] and said switch control signal s(t) are related to each other as follows:

8. The system of claim 6, wherein said switches are MOSFET switches or IGBT switches.

9. The system of claim 1, wherein said voltage controller further comprises an integrator and a saturation block having a low limit value and a high limit value, where said saturation block is configured to allow operation of said integrator as long as said value is between said low limit value and said high limit value, and said saturation block is configured to not allow operation of said integrator outside this range.

10. The system of claim 1, wherein said outer current control loop uses a predetermined value stored in a load profile as said commanded value.

11. The system of claim 1, wherein said super-capacitors are one or more of, or combinations of, the following:

Electric Double Layer Capacitor (EDLC) or Lithium Ion Capacitor (LiC).

12. The system of claim 1, wherein said battery cells comprise at least one fuel cell.

13. A system comprising:

a hybrid super-capacitor/battery system comprising a super-capacitor unit comprising one or more super-capacitors and a battery unit connected to a load, said battery unit rated at a battery output voltage and comprising one or more battery cells, said super-capacitor supplying providing high-power short-duration pulses and said battery unit supplying overall average power and energy demand of a load;

a DC/DC converter connected to said super-capacitor unit and said battery unit, said DC/DC converter allowing charging and discharging of said super-capacitors;

a power control system configured to reduce stresses and energy losses in said battery unit and provide improved charge-capacity and energy capacity, said power control system connected to said DC/DC converter, said power control system comprising an inner voltage control loop comprising a voltage controller and an outer current control loop comprising a current controller, said inner voltage control loop providing control of a load voltage to maintain a value of said load voltage within a predetermined range and regulating said value of load voltage to equal the battery output voltage, said outer current control loop providing said value to inner voltage control loop and controlling a current of said battery unit to a predetermined set-point based on required operating conditions, said set point allowing output of said battery unit to be load-leveled and to allow said super-capacitor unit to provide a pulsed power needed by said load; and

a switch controller having a pulse width modulation (PWM) generator that receives from said voltage controller a duty cycle, D[n], where D[n] is used by said PWM generator to generate a switch control signal, s(t), where s(t) is used by said PWM generator to drive a plurality of switches in order to control a system duty cycle, where driving said switches to increasing said system duty cycle results in a buck operation configured to charge said super-capacitors, and where driving said switches to decrease said system duty cycle results in a boost operation configured to relieve load of said battery unit.

14. The system of claim 13, wherein said set-point is a constant value.

15. The system of claim 13, wherein said set-point comprises a set of values comprising a high set point value and a low set point value, where said power control system configured to not allow said super-capacitors to power said load unless a load current is above said high set-point value, and said power control system configured to not allow said super-capacitors to be recharged until said load current is below said low set-point value.

16. The system of claim 13, wherein said voltage controller is implemented using a proportional-integral (PI) controller.

17. The system of claim 13, wherein said current controller is implemented using a proportional-integral (PI) controller.

18. The system of claim 13, wherein said duty cycle D[n] and said switch control signal s(t) are related to each other as follows:

19. The system of claim 13, wherein said switches are MOSFET switches or IGBT switches.

20. The system of claim 13, wherein said voltage controller further comprises an integrator and a saturation block having a low limit value and a high limit value, where said saturation block is configured to allow operation of said integrator as long as said value is between said low limit value and said high limit value, and said saturation block is configured to not allow operation of said integrator outside this range.

21. The system of claim 13, wherein said outer current control loop uses a predetermined value stored in a load profile as said commanded value.

22. The system of claim 13, wherein said super-capacitors are one or more of, or combinations of, the following:

Electric Double Layer Capacitor (EDLC) or Lithium Ion Capacitor (LiC).

23. The system of claim 13, wherein said battery cells comprise at least one fuel cell.