Drive Axle Motor Control Switching for Powertrain Efficiency

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Solution Overview

Problem

Existing powertrain systems face inefficiencies and mechanical stress due to inadequate motor control strategies, leading to increased fuel consumption, reduced lifespan, and higher maintenance costs.

Innovation Solution

Implementing dynamic motor control by strategically using a combination of Field-Oriented Control (FOC) and Direct Torque Control (DTC) in a vehicle's drive axles, depending on operating conditions, to optimize torque distribution and efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a single motor control strategy is used for all drive axles under all conditions, then the control system is simple, but powertrain efficiency is reduced and mechanical stress increases

Engineering Contradiction:
Improvefuel consumptionVSAvoidmotor control system complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent segments the motor control system by applying different control strategies (FOC and DTC) to different drive axles based on their specific operating conditions. The first drive axle uses FOC while the second drive axle uses DTC, allowing each axle to operate optimally for its conditions, thereby reducing overall energy loss without requiring complete system redesign

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements dynamic motor control that adapts control strategies based on real-time vehicle operating conditions. The system dynamically selects and switches between FOC and DTC strategies for different drive axles depending on acceleration demands, vehicle speed, and torque requirements, optimizing powertrain efficiency across varying operational scenarios

Inventive Principle:
Principle #15Dynamics

2Loss of energy

If FOC is used for steady-state efficiency, then energy loss is reduced, but torque response speed is insufficient for hard acceleration

Engineering Contradiction:
Improvesteady-state energy lossVSAvoidtorque response speed
Core Design Contradiction:
Loss of energyVSSpeed

Solution Approach 1:

The patent applies different control qualities to different drive axles based on local requirements. The first drive axle uses FOC optimized for steady-state efficiency, while the second drive axle uses DTC optimized for fast torque response during acceleration. This local differentiation allows each axle to exhibit the optimal characteristics needed for its specific function in the powertrain system

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the control parameter strategy based on operating conditions. During normal operation, FOC parameters optimize for efficiency; during hard acceleration, the system switches to DTC parameters that prioritize rapid torque response. This parameter adaptation allows the system to achieve both steady-state efficiency and dynamic performance requirements

Inventive Principle:
Principle #35Parameter changes

3Speed

If DTC is used for fast torque response, then acceleration performance is improved, but steady-state efficiency is reduced

Engineering Contradiction:
Improvetorque response speedVSAvoidsteady-state energy loss
Core Design Contradiction:
SpeedVSLoss of energy

Solution Approach 1:

The patent segments the application of DTC to only those drive axles and operating conditions where fast torque response is critical, rather than applying it universally. The second drive axle uses DTC to provide rapid torque response when needed, while the first drive axle uses FOC for steady-state efficiency, thereby limiting energy losses to only the necessary portions of the system

Inventive Principle:
Principle #1Segmentation

4Loss of energy

If uniform torque distribution is applied to all drive axles, then control simplicity is maintained, but powertrain efficiency and component lifespan are reduced

Engineering Contradiction:
Improvepowertrain efficiencyVSAvoidtorque distribution control
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent implements non-uniform torque distribution by applying different control strategies to different drive axles. The first drive axle receives torque references optimized for steady-state efficiency via FOC, while the second drive axle receives torque references optimized for dynamic response via DTC. This local differentiation maximizes overall powertrain efficiency and reduces mechanical stress on individual components

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP4494912A1Dynamic motor control for optimizing powertrain efficiency
Publication Date: 2025.01.22 PACCAR INC
  • EP4494912A1 patent drawingFigure 1A
  • EP4494912A1 patent drawingFigure 1B
  • EP4494912A1 patent drawingFigure 2

AI summary

The present disclosure relates to systems and methods of dynamically modulating use of various motor control strategies (MCSs) to optimize powertrain efficiency. One or a combination of MCSs are strategically and dynamically implemented to regulate torque to drive axle motors of a drive axle based on vehicle operating conditions. In normal acceleration conditions, Field-Oriented Control (FOC) may be used to regulate torque applied to a first drive axle motor and Direct Torque Control (DTC) may be used to regulate torque applied to a second drive axle motor of the drive axle, where the first drive axle motor may operate at peak efficiency and the second drive axle motor may make up for fluctuating torque demand. In cruising speed conditions, FOC may be used to regulate torque applied to both the first and second drive axle motors to operate with high steady-state efficiency at cruising speeds.