Compensation of high voltage loads during pedal lift operation
AssigneeFord Global Technologies, LLC
InventorsRajit Johri, Fazal Urrahman Syed, Francis Thomas Connolly
Life of this patent
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Abstract
A hybrid electric vehicle or a battery electric vehicle has an electric machine, a traction battery, and an accessory powered by the traction battery. The vehicle includes a controller that, in response to a driver lifting their foot off the accelerator pedal, increases the negative motor torque produced by the electric machine for charging the traction battery to compensate for a load applied by the accessory. The controller increases negative motor torque as limited by a maximum motor torque limit. The accessory may be an electric air conditioning compressor and/or a DC/DC inverter.
Claims3
A method of operating a vehicle, comprising:
- responsive to accelerator pedal lift off during propulsion of the vehicle at a speed in an absence of an accessory load demand, controlling an a motor/generator providing driving torque to the drive wheels of the vehicle to provide a first level of negative torque output;
- and
- responsive to accelerator pedal lift off during propulsion of the vehicle at the speed in a presence of the accessory load demand, controlling the motor/generator providing driving torque to the drive wheels of the vehicle to provide a second level of negative torque output that is greater than the first level and that depends on a magnitude of the accessory load demand, wherein the accessory load demand includes an air conditioning compressor and a DC/DC inverter and the second level of negative torque output is calculated by a controller as follows:
- τ
- HV
- =
- (
- P
- A
-
- C
- +
- P
- D
-
- C
-
- D
-
- C
- ω
- mtr
- )
-
-
- τ
- mtr
- c
-
- o
-
- a
-
- s
-
- t
- =
- τ
- HV
- +
- f
- l
-
- o
-
- s
-
- s
- mtr
-
- (
- τ
- HV
- ,
- ω
- mtr
- )
- τ
- lift
- a
-
- d
-
- d
-
- l
- =
- min
-
- (
- max
-
- (
- τ
- mtr
- c
-
- o
-
- a
-
- s
-
- t
- ,
- τ
- mtr
- min
- )
- ,
- τ
- mtr
- max
- )
- τ
- ^
- lift
- =
- τ
- lift
- +
- τ
- lift
- addl
- where PAC is the power required by air conditioning compressor, PDCDC is the DC/DC inverter load, ωmtr is the present motor speed, flossmtr is the motor loss at given torque and speed, and τmtrcoast is the additional torque required to compensate for HV load during lift pedal, where, τmtrmax, τmtrmin are the max and min motor torque limits based on motor mechanical considerations, and where τlift is the original lift-pedal torque, {circumflex over (τ)}lift is the final modified total lift-pedal torque.
Dependencies are inferred from the claim text.