Predictive Magnetization Control for Electric Machine Torque Dynamics
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Solution Overview
Problem
Electric vehicles face a conflict between efficiency and torque dynamics due to the time required to adjust magnetic flux in asynchronous machines, leading to unnecessary losses when rapid torque changes are needed.
Innovation Solution
A method and system that predictively set and adjust the magnetization and torque currents based on anticipated operating state changes, allowing for optimal magnetic flux adjustment before the target time to minimize losses and ensure rapid torque response.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the magnetic flux is permanently set to enable rapid torque changes, then torque dynamics are improved, but unnecessary losses occur due to magnetizing current in all other operating states
Solution Approach 1:
The control system predicts future torque requirements based on current operating parameters and proactively adjusts the magnetic flux before the torque change is actually needed. This preliminary action allows the system to have rapid torque response when needed without maintaining high flux continuously, thereby reducing unnecessary magnetizing current losses during normal operation.
Solution Approach 2:
The magnetic flux is made dynamically adjustable rather than permanently set. The system continuously adapts the flux level based on predicted operating conditions, transitioning between different flux states optimally. This dynamic approach resolves the contradiction by allowing high flux only when torque dynamics are required while maintaining low flux during steady-state operation to minimize losses.
2Loss of energy
If the magnetic flux is adjusted to minimize losses in each operating state, then efficiency is improved, but torque response time increases due to the exponential magnetization time constant
Solution Approach 1:
The system performs preliminary flux adjustment based on predicted future operating states. By anticipating torque requirements and adjusting the magnetic flux in advance, the system avoids the delay associated with exponential magnetization when torque changes are actually requested. This predictive approach maintains efficiency while reducing torque settling time.
Solution Approach 2:
The control system prepares the magnetic flux in advance to cushion against future torque demands. By pre-adjusting the flux level based on predicted operating conditions, the system ensures that when torque changes are needed, the magnetic field is already in an optimal state, preventing delays caused by slow magnetization dynamics.
3Loss of energy
If the magnetic flux is continuously optimized for current operating conditions, then efficiency is improved, but the system cannot respond quickly to sudden torque demands
Solution Approach 1:
The system uses predictive control to perform preliminary flux optimization based on anticipated future operating conditions rather than only current conditions. This allows the system to maintain efficiency while being pre-prepared for upcoming torque demands, thus improving both efficiency and adaptability simultaneously.
Solution Approach 2:
The control system incorporates feedback from operating parameters to continuously predict and adjust the optimal magnetic flux level. By using feedback from current operating states to predict future requirements, the system dynamically optimizes flux for both efficiency and rapid adaptability to changing torque demands.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables efficient and dynamic operation by anticipating torque demands, reducing latency and optimizing magnetic flux for minimal losses, thus resolving the conflict between efficiency and torque dynamics.
Implementation Method 1
A current for magnetizing at least one electric machine is set before the target time
Implementation Method 2
The time-dependent magnetization and demagnetization of the asynchronous machines can be described by an exponential function
Data Source
Figure 1
AI summary
The invention relates to a method for operating at least one electric machine (12) designed to drive a vehicle (2), in which a value for at least one operating parameter of the vehicle (2) is determined, wherein a change in the torque of the at least one electric machine at a target time is predicted from the value of the at least one operating parameter, wherein a current for magnetizing the at least one electric machine (12) before the target time is set to a value, and wherein the value of the current for magnetizing at the target time is adjusted and changed.