Energy management system

• US 8,981,710 B2
• Filed: 09/20/2010
• Issued: 03/17/2015
• Est. Priority Date: 09/20/2010
• Status: Active Grant

• Current Assignee: IPS Systems Incorporated
• Original Assignee: Indy Power Systems, LLC
• Inventors: Hintz, Andrew Stephen, Kramer, Quentin Wayne
• Primary Examiner(s): Tso, Edward
• Assistant Examiner(s): PIGGUSH, AARON C
• Application Number:
  US12/885,999
• Publication Number:
  US 20120068537A1
• Time in Patent Office: 1,639 Days
• Field of Search: 320/103, 320/126, 320/132, 320/134, 320/142, 320/163
• US Class Current: 320/103
• CPC Class Codes: B60L 50/40 using propulsion power supplied by capacitors
• CPC Class Codes: B60L 50/52 characterised by DC-motors
• CPC Class Codes: B60L 53/63 in response to network capacity
• CPC Class Codes: B60L 55/00 Arrangements for supplying energy stored within a vehicle to a power network, i.e. vehicle-to-grid [V2G] arrangements
• CPC Class Codes: B60L 58/21 having the same nominal voltage
• CPC Class Codes: B60L 58/40 for controlling a combination of batteries and fuel cells
• CPC Class Codes: G06F 1/263 Arrangements for using multiple switchable power supplies, e.g. battery and AC G06F1/30 takes precedence
• CPC Class Codes: H02J 1/14 Balancing the load in a network
• CPC Class Codes: H02J 2207/20 Charging or discharging characterised by the power electronics converter
• CPC Class Codes: H02J 7/342 The other DC source being a battery actively interacting with the first one, i.e. battery to battery charging with circuits for polarity protection H02J7/0034
• CPC Class Codes: H02M 3/1582 Buck-boost converters H02M3/1584 takes precedence
• CPC Class Codes: H02M 3/1584 with a plurality of power processing stages connected in parallel
• CPC Class Codes: Y02E 60/00 Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 90/12 Electric charging stations
• CPC Class Codes: Y02T 90/14 Plug-in electric vehicles
• CPC Class Codes: Y02T 90/16 Information or communication technologies improving the operation of electric vehicles
• CPC Class Codes: Y02T 90/40 Application of hydrogen technology to transportation, e.g. using fuel cells
• CPC Class Codes: Y04S 10/126 the energy generation units being or involving electric vehicles [EV] or hybrid vehicles [HEV], i.e. power aggregation of EV or HEV, vehicle to grid arrangements [V2G]

Abstract

An energy management system and method connecting a load to multiple energy sources. The system includes a load connection, source connections for each energy source, a control unit and at least one energy management module having an inductor and four switches. The first source is in parallel with the load. The first switch couples the first source positive terminal to the first inductor end, second switch couples the first source negative terminal to the first inductor end, third switch couples the second source positive terminal to the second inductor end, and fourth switch couples the second source negative terminal to the second inductor end. The control unit controls the four switches of each module to transfer energy between the energy sources through the module inductor. The system can have more than two sources. Modes including one or two switch, synchronous or asynchronous, and buck or boost can be used.

Claims

1. A method for controlling an energy management system that couples a system load to a first energy source and a second energy source, the system load being connected in parallel with the first energy source, the first energy source having a positive terminal and a negative terminal, the second energy source having a positive terminal and a negative terminal;

the energy management system comprising an inductor extending from a first end to a second end, a first switch coupling the positive terminal of the first source to the first end of the inductor, a second switch coupling the negative terminal of the first source to the first end of the inductor, a third switch coupling the positive terminal of the second source to the second end of the inductor, and a fourth switch coupling the negative terminal of the second source to the second end of the inductor;

the method comprising;

evaluating conditions of the system load, the first energy source and the second energy source;

determining the direction and proportion of energy flow between the first energy source, the second energy source and the system load;

determining, based on the direction of energy flow between the first energy source, the second energy source and the system load, which of the first energy source, the second energy source and the system load is an energy flow source and which of the first energy source, the second energy source and the system load is an energy flow destination;

selecting whether to use a two-switch state or a one switch state to move energy from the energy flow source to the energy flow destination;

the two switch state closing either the first and fourth switches, the second and third switches or none of the switches at any one time;

the one switch state closing only one of the switches or none of the switches at any one time;

selecting whether to use a synchronous mode or an asynchronous mode to move energy from the energy flow source to the energy flow destination; and

controlling the switching of the first, second, third and fourth switches to transfer energy from the energy flow source to the energy flow destination through the inductor using the selected one of the two-switch state or the one switch state, and of the synchronous mode or the asynchronous mode.

2. The method of claim 1, wherein the energy management system further comprises a first diode in parallel with the first switch, a second diode in parallel with the second switch, a third diode in parallel with the third switch, and a fourth diode in parallel with the fourth switch, and the method further comprising:

when the two-switch state and synchronous mode are both selected, closing two switches to move energy from the energy flow source to the inductor and then opening those two switches and closing the other two switches to move energy from the inductor to the energy flow destination; and

when the two-switch state and asynchronous mode are both selected, closing two switches to move energy from the energy flow source to the inductor and then opening those two switches to move energy from the inductor to the energy flow destination through two of the first, second, third and fourth diodes.

3. The method of claim 1, wherein the energy management system further comprises a first diode in parallel with the first switch, a second diode in parallel with the second switch, a third diode in parallel with the third switch, and a fourth diode in parallel with the fourth switch, and the method further comprising:

determining a voltage of the energy flow source;

determining a voltage of the energy flow destination;

when the one-switch state is selected and the voltage of the energy flow source is less than the voltage of the energy flow destination, controlling the switching of the first, second, third and fourth switches to transfer energy between the energy flow source and the energy flow destination through the inductor using a boost conversion mode; and

when the one-switch state is selected and the voltage of the energy flow source is not less than the voltage of the energy flow destination, controlling the switching of the first, second, third and fourth switches to transfer energy between the energy flow source and the energy flow destination through the inductor using a buck conversion mode.

4. The method of claim 3, further comprising:

monitoring the voltage of the energy flow source;

monitoring the voltage of the energy flow destination;

when using the buck conversion mode and the voltage of the energy flow source becomes less than the voltage of the energy flow destination, switching from buck conversion mode to boost conversion mode.

5. A method for controlling an energy management system that couples a system load to a first energy source and a second energy source, the system load being connected in parallel with the first energy source, the first energy source having a positive terminal and a negative terminal, the second energy source having a positive terminal and a negative terminal;

the energy management system comprising a plurality of energy management modules;

each of the plurality of energy management modules comprising an inductor extending from a first end to a second end;

a first switch coupling the positive terminal of the first source to the first end of the inductor;

a second switch coupling the negative terminal of the first source to the first end of the inductor;

a third switch coupling the positive terminal of the second source to the second end of the inductor; and

a fourth switch coupling the negative terminal of the second source to the second end of the inductor, the method comprising;

evaluating conditions of the system load, the first energy source and the second energy source;

determining whether to control the energy management system using a manual mode or an automatic mode; and

when controlling the energy management system using the manual mode;

receiving user input parameters defining the direction and proportion of energy flow between the first energy source, the second energy source and the system load;

controlling the switching of the first, second, third and fourth switches of each of the plurality of energy management modules to transfer energy in accordance with the user input parameters;

determining, based on the direction of energy flow between the first energy source, the second energy source and the system load, which of the first energy source, the second energy source and the system load is an energy flow source and which of the first energy source, the second energy source and the system load is an energy flow destination;

apportioning the energy flow between each of the plurality of energy management modules in accordance with the user input parameters;

for each of the plurality of energy management modules, selecting whether to use a two-switch state or a one switch state to move the apportioned amount of energy from the energy flow source to the energy flow destination;

for each of the plurality of energy management modules, selecting whether to use a synchronous mode or an asynchronous mode to move the apportioned amount of energy from the energy flow source to the energy flow destination; and

controlling the switching of the first, second, third and fourth switches of each of the plurality of energy management modules to transfer energy from the energy flow source to the energy flow destination through the respective inductor using the selected one of the two-switch state or the one switch state, and of the synchronous mode or the asynchronous mode.

6. The method of claim 5, further comprising:

selecting N of the plurality of energy management modules to transfer energy between the first energy source and the second energy source;

synchronizing the switching of each of the N selected energy management modules to be out of phase with each other, such that if the time period for the switching of all of the energy management modules is T_sw, then controlling each energy management module to transfer energy for a period of T_sw/N, and offsetting the start time of each successive energy management module by T_sw/N.

7. The method of claim 5, further comprising:

detecting each of the plurality of energy management modules controlled by the energy management system.

8. The method of claim 5, further comprising:

receiving sensor readings indicating the condition of the system load, the first energy source and the second energy source;

using the sensor readings to evaluate the condition of the system load, the first energy source and the second energy source; and

monitoring the sensor readings while controlling the switching of the first, second, third and fourth switches of each of the plurality of energy management modules.

9. The method of claim 5, wherein each of the plurality of energy management modules further comprises a first diode in parallel with the first switch, a second diode in parallel with the second switch, a third diode in parallel with the third switch, and a fourth diode in parallel with the fourth switch, and the method further comprises for each of the plurality of energy management modules:

when the two-switch state and synchronous mode are both selected, closing two switches of the energy management module to move energy from the energy flow source to the inductor of the energy management module, and then opening those two switches and closing the other two switches of the energy management module to move energy from the inductor of the energy management module to the energy flow destination; and

when the two-switch state and asynchronous mode are both selected, closing two switches of the energy management module to move energy from the energy flow source to the inductor of the energy management module, and then opening those two switches and moving energy from the inductor of the energy management module to the energy flow destination through two of the first, second, third and fourth diodes of the energy management module.

10. The method of claim 5, wherein each of the plurality of energy management modules further comprises a first diode in parallel with the first switch, a second diode in parallel with the second switch, a third diode in parallel with the third switch, and a fourth diode in parallel with the fourth switch, and the method further comprises:

determining a voltage of the energy flow source;

determining a voltage of the energy flow destination;

when the one-switch state is selected and the voltage of the energy flow source is less than the voltage of the energy flow destination, for each of the plurality of energy management modules, controlling the switching of the first, second, third and fourth switches of the energy management module to transfer energy between the energy flow source and the energy flow destination through the inductor of the energy management module using a boost conversion mode; and

when the one-switch state is selected and the voltage of the energy flow source is not less than the voltage of the energy flow destination, for each of the plurality of energy management modules, controlling the switching of the first, second, third and fourth switches of the energy management module to transfer energy between the energy flow source and the energy flow destination through the inductor of the energy management module using a buck conversion mode.

11. The method of claim 10, further comprising:

monitoring the voltage of the energy flow source;

monitoring the voltage of the energy flow destination;

when using the buck conversion mode and the voltage of the energy flow source becomes less than the voltage of the energy flow destination, for each of the plurality of energy management modules, switching from buck conversion mode to boost conversion mode.

12. A method for controlling an energy management system that couples a system load to a first energy source and a second energy source, the system load being connected in parallel with the first energy source, the first energy source having a positive terminal and a negative terminal, the second energy source having a positive terminal and a negative terminal;

the energy management system comprising a plurality of energy management modules;

each of the plurality of energy management modules comprising an inductor extending from a first end to a second end;

a first switch coupling the positive terminal of the first source to the first end of the inductor;

a second switch coupling the negative terminal of the first source to the first end of the inductor;

a third switch coupling the positive terminal of the second source to the second end of the inductor; and

a fourth switch coupling the negative terminal of the second source to the second end of the inductor, the method comprising;

evaluating conditions of the system load, the first energy source and the second energy source;

determining whether to control the energy management system using a manual mode or an automatic mode; and

when controlling the energy management system using the automatic mode;

determining the direction and proportion of energy flow between the first energy source, the second energy source and the system load;

determining, based on the direction of energy flow between the first energy source, the second energy source and the system load, which of the first energy source, the second energy source and the system load is an energy flow source and which of the first energy source, the second energy source and the system load is an energy flow destination;

apportioning the energy flow between each of the plurality of energy management modules;

for each of the plurality of energy management modules, selecting whether to use a two-switch state or a one switch state to move the apportioned amount of energy from the energy flow source to the energy flow destination;

the two switch state closing either the first and fourth switches, the second and third switches or none of the switches at any one time;

the one switch state closing only one of the switches or none of the switches at any one time;

for each of the plurality of energy management modules, selecting whether to use a synchronous mode or an asynchronous mode to move energy from the energy flow source to the energy flow destination; and

controlling the switching of the first, second, third and fourth switches of each of the plurality of energy management modules to transfer energy from the energy flow source to the energy flow destination through the respective inductor using the selected one of the two-switch state or the one switch state, and of the synchronous mode or the asynchronous mode.

13. The method of claim 12, wherein determining the direction and proportion of energy flow between the first energy source and the second energy source and the system load comprises:

determining whether the system load is using energy from the first and second energy sources;

determining whether the system load is supplying energy to the first and second energy sources; and

when the system load is neither using nor supplying energy, determining whether to perform energy balancing between the first and second energy sources.

14. The method of claim 13 wherein, when it is determined that the system load is using energy from the first and second energy sources, the method further comprises:

determining whether the amount of current to be supplied to the system load is greater than a threshold current, and setting apportionment of the energy flow from the first and second energy sources to the system load accordingly;

determining whether at least one of a voltage of the first energy source is less than a threshold voltage and a state-of-charge of the first energy source is less than a threshold state-of-charge, and apportioning the energy flow from the first and second energy sources to the system load accordingly; and

when none of the threshold current, the threshold voltage and the threshold state-of-charge are exceeded, comparing a timer to a timeout value.

15. The method of claim 13, wherein when it is determined that the system load is supplying energy to the first and second energy sources, the method further comprises:

determining whether the amount of current to be supplied by the system load is greater than a threshold current, and setting apportionment of the energy flow from the system load to the first and second energy sources accordingly;

determining whether at least one of a voltage of the first energy source is greater than a threshold voltage and a state-of-charge of the first energy source is greater than a threshold state-of-charge, and apportioning the energy flow from the system load to the first and second energy sources accordingly;

when none of the threshold current, the threshold voltage and the threshold state-of-charge are exceeded, comparing a timer to a timeout value.

16. The method of claim 13, wherein when it is determined to perform energy balancing between the first and second energy sources, the method further comprises:

determining a state-of-charge of the first energy source;

determining a state-of-charge of the second energy source;

comparing the state-of-charge of the first energy source to maximum and minimum state-of-charge values;

comparing the state-of-charge of the second energy source to maximum and minimum state-of-charge values;

apportioning the energy flow between the first energy source and the second energy sources based on the comparisons with the maximum and minimum state-of-charge values.

17. The method of claim 12, further comprising:

selecting N of the plurality of energy management modules to transfer energy between the first energy source and the second energy source;

synchronizing the switching of each of the N selected energy management modules to be out of phase with each other, such that if the time period for the switching of all of the energy management modules is T_sw, then controlling each energy management module to transfer energy for a period of T_sw/N, and offsetting the start time of each successive energy management module by T_sw/N.

18. The method of claim 12, further comprising:

detecting each of the plurality of energy management modules controlled by the energy management system.

19. The method of claim 12, further comprising:

receiving sensor readings indicating the condition of the system load, the first energy source and the second energy source;

using the sensor readings to evaluate the condition of the system load, the first energy source and the second energy source; and

monitoring the sensor readings while controlling the switching of the first, second, third and fourth switches of each of the plurality of energy management modules.

20. The method of claim 12, wherein each of the plurality of energy management modules further comprises a first diode in parallel with the first switch, a second diode in parallel with the second switch, a third diode in parallel with the third switch, and a fourth diode in parallel with the fourth switch, and the method further comprises for each of the plurality of energy management modules:

when the two-switch state and synchronous mode are both selected, closing two switches of the energy management module to move energy from the energy flow source to the inductor of the energy management module, and then opening those two switches and closing the other two switches of the energy management module to move energy from the inductor of the energy management module to the energy flow destination; and

when the two-switch state and asynchronous mode are both selected, closing two switches of the energy management module to move energy from the energy flow source to the inductor of the energy management module, and then opening those two switches to move energy from the inductor of the energy management module to the energy flow destination through two of the first, second, third and fourth diodes of the energy management module.

21. The method of claim 12, wherein each of the plurality of energy management modules further comprises a first diode in parallel with the first switch, a second diode in parallel with the second switch, a third diode in parallel with the third switch, and a fourth diode in parallel with the fourth switch, and the method further comprises:

determining a voltage of the energy flow source;

determining a voltage of the energy flow destination;

when the one-switch state is selected and the voltage of the energy flow source is less than the voltage of the energy flow destination, for each of the plurality of energy management modules, controlling the switching of the first, second, third and fourth switches of the energy management module to transfer energy between the energy flow source and the energy flow destination through the inductor of the energy management module using a boost conversion mode; and

when the one-switch state is selected and the voltage of the energy flow source is not less than the voltage of the energy flow destination, for each of the plurality of energy management modules, controlling the switching of the first, second, third and fourth switches of the energy management module to transfer energy between the energy flow source and the energy flow destination through the inductor of the energy management module using a buck conversion mode.

22. The method of claim 21, further comprising:

monitoring the voltage of the energy flow source;

monitoring the voltage of the energy flow destination;

when using the buck conversion mode and the voltage of the energy flow source becomes less than the voltage of the energy flow destination, for each of the plurality of energy management modules, switching from buck conversion mode to boost conversion mode.