Hill hold for electric vehicle

• US 6,825,624 B2
• Filed: 03/11/2003
• Issued: 11/30/2004
• Est. Priority Date: 03/11/2003
• Status: Expired due to Fees

• Current Assignee: Visteon Global Technologies Incorporated (Visteon Corporation)
• Original Assignee: Visteon Global Technologies Incorporated (Visteon Corporation)
• Inventors: Teimor, Mehrdad, Anwar, Mohammad Nazmul
• Primary Examiner(s): Masih, Karen
• Application Number:
  US10/386,075
• Publication Number:
  US 20040178754A1
• Time in Patent Office: 630 Days
• Field of Search: 318/432, 318/433, 318/727, 318/801, 318/807, 318/811
• US Class Current: 318/432
• CPC Class Codes: H02P 3/025 holding the rotor in a fixed position after deceleration
• CPC Class Codes: H02P 3/18 for stopping or slowing an ac motor
• CPC Class Codes: H02P 6/24 Arrangements for stopping

Abstract

A hill hold apparatus and operating strategy for an electric or hybrid electric vehicle is disclosed. The apparatus includes a three-phase machine that is coupled to drive wheels. The machine is powered by a pulse width modulated inverter having at least a first half-bridge coupled to a first machine phase, a second half-bridge coupled to a second machine phase, and a third half-bridge coupled to a third machine phase. The operating strategy employs predetermined switching modes to minimize and distribute the power loss among the power switches in the inverter and the machine phases.

Claims

1. A method of maintaining a vehicle in a stopped position on an incline comprising the steps of:

coupling a machine with at least a first phase, a second phase, and a third phase to at least one drive wheel of the vehicle;

selectively supplying energy to the first phase, the second phase and the third phase with a pulse width modulated inverter having at least a first half-bridge coupled to the first phase, a second half-bridge coupled to the second phase, and a third half-bridge coupled to the third phase; and

maintaining a torque in the machine at an approximately zero rotational speed by switching the inverter between one of;

a mode 1 for a first percentage of a pulse width modulated switching period and a mode 7 for a remaining percentage of the pulse width modulated switching period;

a mode 2 for the first percentage of the pulse width modulated switching period and the mode 7 for the remaining percentage of the pulse width modulated switching period; and

a mode 6 for the first percentage of the pulse width modulated switching period and the mode 7 for the remaining percentage of the pulse width modulated switching period.

2. The method of claim 1 wherein the step of maintaining the torque is further defined by employing the mode 1 and mode 7, and by increasing the first percentage of the mode 1 operation and correspondingly decreasing the remaining percentage of the mode 7 operation when the torque required to maintain the vehicle in a stopped position is increased.

3. The method of claim 1 wherein the step of maintaining the torque is further defined by employing the mode 2 and mode 7, and by increasing the first percentage of the mode 2 operation and correspondingly decreasing the remaining percentage of the mode 7 operation when the torque required to maintain the vehicle in a stopped position is increased.

4. The method of claim 1 wherein the step of maintaining the torque is further defined by employing the mode 6 and mode 7, and by increasing the first percentage of the mode 6 operation and correspondingly decreasing the remaining percentage of the mode 7 operation when the torque required to maintain the vehicle in a stopped position is increased.

5. A method of maintaining a vehicle in a stopped position on an incline comprising the steps of:

coupling a machine with at least a first phase, a second phase, and a third phase to at least one drive wheel of the vehicle;

selectively supplying energy to the first phase, the second phase and the third phase with a pulse width modulated inverter having at least a first half-bridge coupled to the first phase, a second half-bridge coupled to the second phase, and a third half-bridge coupled to the third phase; and

maintaining a torque in the machine at an approximately zero rotational speed by;

switching the inverter between a mode 1 for a first percentage of a pulse width modulated switching period and a mode 7 for a remaining percentage of the pulse width modulated switching period, for about a first one third of a predetermined time period, with the predetermined time period being at least three times longer than the pulse width modulated switching period;

switching the inverter between a mode 6 for the first percentage of the pulse with modulated switching period and a mode 8 for the remaining percentage of the pulse width modulated switching period, for about a second one third of the predetermined time period; and

switching the inverter between a mode 5 for the first percentage of the pulse width modulated switching period and the mode 7 for the remaining percentage of the pulse width modulated switching period, for about a third one third of the predetermined time period.

6. A hill hold apparatus for a vehicle comprising:

a machine adapted to couple to and drive at least one drive wheel of the vehicle, with the machine including at least a first phase, a second phase, and a third phase;

a pulse width modulated inverter having at least a first half-bridge coupled to the first phase, a second half-bridge coupled to the second phase, and a third half-bridge coupled to the third phase, with the inverter adapted to connect to a source of electrical energy; and

a machine controller connected to and adapted to control the first half-bridge, to the second half-bridge and the third half-bridge of the inverter and including a hill hold strategy for controlling the inverter to maintain a torque in the machine at an approximately zero rotational speed by switching the inverter between one of;

a mode 1 for a first percentage of a pulse width modulated switching period and a mode 7 for a remaining percentage of the pulse width modulated switching period;

a mode 2 for the first percentage of the pulse width modulated switching period and the mode 7 for the remaining percentage of the pulse width modulated switching period; and

a mode 6 for the first percentage of the pulse width modulated switching period and the mode 7 for the remaining percentage of the pulse width modulated switching period.

7. The hill hold apparatus of claim 6 further including a capacitor connected in parallel with at least one of the first half-bridge, the second half-bridge and the third half-bridge.

8. The hill hold apparatus of claim 6 wherein the machine is a permanent magnet motor.

9. The hill hold apparatus of claim 6 wherein the machine is an induction motor.