Dual-Motor EV Power Allocation During Gear Shifts
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Solution Overview
Problem
The control of powertrain operations in electric vehicles with multiple electric machines becomes complex during gear shifting, requiring improved power allocation strategies to optimize propulsion and regenerative power distribution.
Innovation Solution
A method for allocating power between electric machines in a powertrain, involving predefined power ratios before and during gear changes, where power is dynamically adjusted between the machines to ensure efficient propulsion and regenerative power usage, with power limits set based on the State of Power (SoP) from the energy storage system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If power is allocated to multiple electric machines during gear shifting, then propulsion power is maintained, but control complexity increases
Solution Approach 1:
The patent applies dynamics by making the power allocation ratio variable rather than fixed. The controlling apparatus dynamically adjusts the power allocation between first and second electric machines based on the gear shifting state. During gear shifting, the system transitions from a first power allocation ratio to a second power allocation ratio, enabling adaptive control that maintains propulsion power while managing control complexity through state-dependent adjustment strategies.
2Productivity
If power allocation ratio is changed during gear change, then power distribution efficiency is improved, but system response time requirement increases
Solution Approach 1:
The patent applies preliminary action by detecting the gear shifting state in advance and proactively adjusting the power allocation ratio before the gear change is complete. The controlling apparatus monitors the gear shifting process and transitions the power allocation from the first ratio to the second ratio during the shifting event, ensuring that power distribution is optimized in advance rather than reactively after the shift occurs.
Data Source
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AI summary
The present invention relates to a method for allocating power between electric machines (20, 30) in a powertrain (10,100) of an electric vehicle (1). The electric vehicle (1) comprises a gearbox (50) having an input shaft (52) and an output shaft (54) configured to transmit a first torque to the wheels of the vehicle (1), a first electric machine (20) having an output shaft (22) coupled to the input shaft (52) of the gearbox (50), and a second electric machine (30) configured to supply a second torque to wheels of the vehicle (1). The method comprises: prior to a gear change of the first electric machine (20), allocating (S10) power to the first and second electric machines (20, 30) according to a first power ratio (PR1); in response of an intended gear change of the first electric machine (20), allocating power (S20) to the first and second electric machines (20, 30) according to a second power ratio (PR2).