Device and method for reducing rotational imbalances of a drive train for a hybrid vehicle

A method for reducing a rotational imbalance of a drive train of a hybrid vehicle, wherein the drive train includes an internal-combustion engine, an electric machine, and a crankshaft, the method comprising:

• actuating the electric machine in response to an actuation signal provided by an adaptive feed forward control, wherein the actuation signal represents a desired torque to be generated by the electric machine, so that the electric machine outputs a torque that is at least approximately inverse with respect to the rotational imbalance,
• wherein the act of actuating the electric machine includes
• receiving by the adaptive feed forward control an estimate of an interference torque generated by an interference torque estimator based on a rotational speed of the electric machine,
• generating with a frequency generator of the adaptive feed forward control a frequency vector from a frequency generator based on a rotational speed of the internal combustion engine, the frequency vector being in the form of a matrix A(ω, c), where ω represents a vector of individual frequencies corresponding to expected periodic oscillations associated with the rotational speed of the internal-combustion engine and c represents a vector of corresponding individual damping quantities,
• receiving the frequency vector by an interference variable monitor of the adaptive feed forward control,
• generating with the interference variable monitor, based on the frequency vector A(ω, c) received from the frequency generator, an expected oscillations vector in the form of x(k+1), where x(k+1)=A(ω, c)x(k)+Le(k), x(k) represents a previously determined expected oscillations vector and Le(k) represents a matrix of learning speeds for adaptation in response to the estimated interference torque, and
• generating with the interference variable monitor the actuation signal for actuating the electric machine in the form of a desired electric machine output torque, the desired electric machine output torque being in the form of u=Cx(k), where C is a vector related to the frequency vector matrix A(ω, c) by the relationships of
• A
• i
• =
• [
• 0
• e
• -
• ω
• i
• ⁢
• c
• i
• ⁢
• T
• s
• -
• e
• -
• ω
• i
• ⁢
• c
• i
• ⁢
• T
• s
• 2
• ⁢
• e
• -
• ω
• i
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• c
• i
• ⁢
• T
• s
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• cos
• ⁡
• (
• ω
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• 1
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• c
• i
• 2
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• T
• s
• )
• ]
• ,
• C
• i
• =
• [
• 1
• 0
• ]
• for an ith individual frequency ωi and ith individual damping ci in a scanning time Ts between k and k+1 cycles of the adaptive feed forward control, and
• A
• =
• [
• A
• 1
• …
• 0
• ⋮
• ⋱
• ⋮
• 0
• …
• A
• N
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• ,
• C
• =
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• C
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• ,
• corresponding to superposition of N sinusoidal oscillations,
• generating with the electric machine the desired electric machine output torque in response to the actuation signal output by the adaptive feed forward control to the electric machine, and
• applying the desired electric machine output torque generated by the electric machine to the crankshaft for superimposition on a torque generated by the internal-combustion engine.