Control system for electric vehicles
AssigneeFuture Motion, Inc.
InventorsKyle Jonathan Doerksen, Daniel J. Wood, Julian De La Rua
Life of this patent
Estimating the term…
Abstract
When an electric vehicle is traveling downhill, experiencing regenerative braking, or otherwise forcing the vehicle motor to turn faster than the commanded motor torque, the vehicle motor produces electrical energy that can be used to recharge a vehicle battery. However, if the vehicle battery is already nearly or fully charged, the excess electrical energy produced may damage the battery. Control systems described herein may reduce and/or dispose of the excess energy by manipulating the motor flux (i.e., direct) current and quadrature current independently.
Claims20
A control system for an electric vehicle, the control system comprising:
- a power supply;
- an electric motor coupled to the power supply;
- and
- a motor controller having a field-oriented control (FOC) scheme configured to control the electric motor by manipulating a direct current aligned with a rotating rotor flux angle and a quadrature current defined at ninety degrees from the rotating rotor flux angle, wherein manipulation of the direct current is independent of manipulation of the quadrature current, and the motor controller includes processing logic configured to:
- determine whether a counter electromotive force (CEMF) of the electric motor exceeds a voltage of the power supply by comparing a bus voltage of the power supply to a voltage threshold;
- and
- in response to the bus voltage being greater than the voltage threshold, weakening a motor flux of the electric motor and reducing the CEMF by automatically increasing the direct current.
An electric vehicle comprising:
- one or more wheels;
- an electric hub motor coupled to a power supply and configured to drive the one or more wheels;
- a motor controller having a field-oriented control (FOC) scheme configured to control the electric hub motor by manipulating a direct current aligned with a rotating rotor flux angle and a quadrature current defined at ninety degrees from the rotating rotor flux angle, wherein manipulation of the direct current is independent of manipulation of the quadrature current, and the motor controller includes processing logic configured to:
- determine whether a counter electromotive force (CEMF) of the electric motor exceeds a voltage of the power supply by comparing a bus voltage of the power supply to a voltage threshold;
- and
- in response to the bus voltage being greater than the voltage threshold, weakening a motor flux of the electric motor and reducing the CEMF by automatically increasing the direct current.
A method for preventing damage to a power supply of an electric vehicle during regenerative braking, the method comprising:
- controlling an electric motor using a motor controller having a field-oriented control (FOC) scheme configured to control the electric motor by manipulating a direct current aligned with a rotating rotor flux angle and a quadrature current defined at ninety degrees from the rotating rotor flux angle, wherein manipulation of the direct current is independent of manipulation of the quadrature current;
- using processing logic of the motor controller to determine whether a counter electromotive force (CEMF) of the electric motor exceeds a voltage of the power supply;
- and
- in response to the CEMF of the electric motor exceeding the voltage of the power supply, weakening a motor flux of the electric motor and reducing the CEMF by automatically increasing the direct current.
Dependencies are inferred from the claim text.