Electrically Variable Transmission Motor Torque Control
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Solution Overview
Problem
Current hybrid electrically variable transmissions face challenges in managing multiple parameters such as clutch, engine, and motor torques, battery power levels, and gear shifting for optimal fuel economy and operational efficiency.
Innovation Solution
A method and controller that determine and set torque limits for electric motors based on minimum battery power, ensuring efficient operation by optimizing torque distribution between the first and second electric motors, and adjusting torque limits according to clutch and motor limitations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If torque distribution between multiple electric motors is optimized to improve fuel economy, then energy efficiency improves, but control complexity increases
Solution Approach 1:
The system dynamically adjusts torque distribution parameters between multiple electric motors based on real-time operating conditions. The controller modifies torque limits and power allocation parameters to optimize fuel economy across different drive modes (series hybrid, parallel hybrid, electric-only), resolving the contradiction by making the system adaptive rather than fixed
Solution Approach 2:
The control system transitions between different operational modes (series hybrid mode, parallel hybrid mode, electric-only mode) based on vehicle speed, load, and battery state. This dynamic switching allows the system to achieve optimal fuel economy across varying conditions while managing control complexity through predefined mode strategies
2Use of energy by moving object
If battery power levels are tightly controlled to minimize power consumption, then energy efficiency improves, but system adaptability deteriorates
Solution Approach 1:
The system dynamically adjusts battery power usage based on vehicle operating conditions, switching between charge depletion mode, charge sustain mode, and charge acceptance mode. This allows tight control of battery power consumption while maintaining adaptability across different drive modes and battery states
Solution Approach 2:
The controller modifies battery power limits and charge/discharge rates based on battery state of charge, temperature, and vehicle demand. This enables efficient battery power management that adapts to varying operational requirements without sacrificing system versatility
3Adaptability or versatility
If multiple clutches and gear sets are used to enable hybrid operation, then functional versatility improves, but device complexity increases
Solution Approach 1:
The transmission system is divided into distinct functional modules including series hybrid mode, parallel hybrid mode, and electric-only mode capabilities. Each mode uses specific subsets of clutches and gear sets, allowing the system to achieve functional versatility while managing complexity through modular operation
Solution Approach 2:
The electric motors are designed to perform multiple functions: propulsion in electric-only mode, power assistance in parallel hybrid mode, and power generation in series hybrid mode. This multi-functionality reduces the need for separate dedicated components, managing structural complexity while maintaining drive mode versatility
4Use of energy by moving object
If torque limits are dynamically adjusted based on minimum battery power, then energy efficiency improves, but control difficulty increases
Solution Approach 1:
The system dynamically changes torque limits for electric motors based on calculated minimum battery power requirements. The controller adjusts torque parameters in real-time to maintain energy efficiency while managing control difficulty through established algorithms and boundary condition definitions
Data Source
AI summary
A motor operation control system and method for controlling first and second electric motors of an electrically variable transmission. The system and method determine a minimum battery power associated with a torque of the second electric motor, set the torque of the second electric motor based on the determined minimum battery power, and set a torque of the first electric motor based on the determined minimum battery power.