Method of current interaction in an electric motor drive system having a load-dependent current generating system

• US 6,452,352 B1
• Filed: 11/02/2000
• Issued: 09/17/2002
• Est. Priority Date: 11/02/2000
• Status: Expired due to Term

• Current Assignee: Continental Automotive Systems, Inc. (Continental AG)
• Original Assignee: Ballard Power Systems Corporation (Superior Plus Corporation)
• Inventors: Farkas, Kenneth James
• Primary Examiner(s): Nappi, Robert E.
• Assistant Examiner(s): Leykin, Rita
• Application Number:
  US09/705,236
• Time in Patent Office: 684 Days
• Field of Search: 318/432, 318/433, 318/139, 318/140, 318/151
• US Class Current: 318/433
• CPC Class Codes: B60L 15/2045 for optimising the use of energy
• CPC Class Codes: B60L 2220/12 Induction machines
• CPC Class Codes: B60L 58/30 for monitoring or controlling fuel cells
• CPC Class Codes: H02P 29/02 Providing protection against overload without automatic interruption of supply protection against faults of stepper motors H02P8/36
• CPC Class Codes: Y02T 10/64 Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/72 Electric energy management in electromobility
• CPC Class Codes: Y02T 90/40 Application of hydrogen technology to transportation, e.g. using fuel cells

Abstract

This invention provides a process for determining a desired torque (load) value for a load-dependent current generating system, such as a fuel cell system, in an electric vehicle. The process calculates load based on various driver demands such as accelerator position, brake position, Key on/off, Gear selector position, and system component temperatures. Additionally, the process considers the amount of current available from the load-dependent current generating system and matches that current to the current drawn by the electric motor. The process can be applied to a direct current (DC) electric traction motor or an alternating current (AC) induction motor.

Claims

1. A process for controlling an electric motor drive system, comprising the steps of:

reading vehicle sensors to determine driver torque demand;

calculating motor current demand (load) for an electric driving motor, based on the driver torque demand;

calculating a desired current output for a load-dependent current generating system based on said desired values for motor current demand;

calculating available current output from the load-dependent current generating system; and

supplying current from the load-dependent generating system to the electric driving motor.

2. The process of claim 1 further comprising the step of matching the desired current output with the available current output.

3. The process of claim 1 wherein the vehicle sensors comprise:

sensing accelerator position;

sensing brake position;

sensing key on;

sensing gear selector position; and

sensing load-dependent current generating system temperature.

4. The process of claim 1 wherein the load-dependent current generating system is a fuel cell.

5. The process of claim 1 wherein the drive motor is any electric traction motor.

6. The process of claim 1 wherein the drive motor is an alternating current induction motor.

7. A system to control an electric motor drive system, comprising:

a system to read vehicle sensors to determine driver torque demand;

a system to calculate motor current demand (load) for an electric driving motor, based on the driver torque demand;

a system to calculate a desired current output for a load-dependent current generating system based on said desired values for motor current demand;

a system to calculate available current output from the load-dependent current generating system; and

a system to supply current from the load-dependent generating system to the electric driving motor.

8. The system of claim 7 further comprising a system to match the desired current output with the available current output.

9. The system of claim 7 wherein the vehicle sensors comprise sensors for:

accelerator position;

brake position;

key on;

gear selector position; and

load-dependent current generating system temperature.

10. The system of claim 7 wherein the load-dependent current generating system is a fuel cell.

11. The system of claim 7 wherein the drive motor is any electric traction motor.

12. The system of claim 7 wherein the drive motor is an alternating current induction motor.