SYSTEM FOR CONTROLLING THE POWER OUTPUT OF A FUEL CELL STACK AND BATTERY

• US 20090258269A1
• Filed: 06/26/2009
• Published: 10/15/2009
• Est. Priority Date: 06/09/2006
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations Incorporated (Motors Liquidation Co. GUC Trust)
• Inventors: Schaffnit, Jochen, Maier, Oliver, Kilian, Peter
• Granted Patent: US 7,847,513 B2
• Time in Patent Office: Days
• US Class Current: 429/513
• CPC Class Codes: B60L 2210/20 AC to AC converters
• CPC Class Codes: B60L 58/40 for controlling a combination of batteries and fuel cells
• CPC Class Codes: H01M 16/006 of fuel cells with rechargeable batteries
• CPC Class Codes: H01M 8/04619 of fuel cell stacks
• CPC Class Codes: H01M 8/04626 of auxiliary devices, e.g. batteries, capacitors
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02E 60/50 Fuel cells
• 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 10/72 Electric energy management in electromobility
• CPC Class Codes: Y02T 10/92 Energy efficient charging or discharging systems for batteries, ultracapacitors, supercapacitors or double-layer capacitors specially adapted for vehicles
• CPC Class Codes: Y02T 90/40 Application of hydrogen technology to transportation, e.g. using fuel cells

Abstract

A system for controlling the power output of a fuel cell stack and a battery in a hybrid fuel cell system. The system includes a power damping filter that receives a power request signal, and damps the request to reduce large changes in the power request. A battery state of charge controller receives the difference between a battery state of charge set-point and the actual battery state of charge, and provides a battery power signal that attempts to maintain the battery state of charge at the set-point. The damped power signal and the battery power signal are added to generate a system power demand signal that satisfies the driver power request using the battery power and fuel cell stack power, and uses the fuel cell stack power to charge the battery during low power transients or if the battery state of charge is below the set-point.

Claims

1. A fuel cell system comprising:

a fuel cell stack;

a power source;

a power damping processor responsive to a driver request signal and providing a damped driver request signal;

a subtractor responsive to a predetermined power source state of charge (SOC) set-point signal and an actual power source SOC signal, said subtractor providing a difference signal between the SOC set-point and the actual power source SOC;

an SOC controller responsive to the difference signal and generating a power source SOC signal;

an adder adding the damped power request signal and the power source SOC signal to provide a fuel cell system power signal; and

a power balancing module responsive to the fuel cell system power signal and determining how much power is provided by the fuel cell stack, how much power is provided by the battery and how much fuel cell stack power is used to recharge the battery during low power and high power transients.

2. The system according to claim 1 wherein the power damping processor is a first order filter.

3. The system according to claim 1 wherein the SOC controller is a PI controller.

4. The system according to claim 1 wherein the SOC controller attempts to maintain the battery state of charge at the SOC set-point.

5. The system according to claim 4 wherein the SOC set-point is about 65% of the maximum battery SOC.

6. The system according to claim 1 wherein the power source is a battery.

7. The system according to claim 1 wherein the controller provides excess fuel cell stack power at low power transients to charge the battery and uses battery power to supplement the fuel cell stack power at high power transients.

8. The system according to claim 1 wherein the system is on a hybrid fuel cell system vehicle.