Hill hold for electric vehicle
First Claim
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.
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Accused Products
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.
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Citations
9 Claims
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1. A method of maintaining a vehicle in a stopped position on an incline comprising the steps of:
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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. - View Dependent Claims (2, 3, 4)
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5. A method of maintaining a vehicle in a stopped position on an incline comprising the steps of:
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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.
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6. A hill hold apparatus for a vehicle comprising:
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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, 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. - View Dependent Claims (7, 8, 9)
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Specification