Variable Magnetization Control with Hysteresis for Lower Driving Loss
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Solution Overview
Problem
Existing controllers for variable magnetization machines in electric and hybrid electric vehicles face inefficiencies due to high frequency changes in magnetization levels, leading to significant losses and steady-state errors, which hinder maximum efficiency.
Innovation Solution
A hysteresis control component with a sample and hold circuit and proportional-integral compensator is used to receive an ideal magnetization state signal, output an actual signal, and modify it based on error values, reducing steady-state errors and minimizing the number of magnetization changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the magnetization level is increased to increase torque output, then the vehicle acceleration performance is improved, but the number of magnetization changes increases leading to significant energy losses
Solution Approach 1:
The controller dynamically adjusts the magnetization level of the motor based on real-time driving conditions and torque requirements. Instead of using fixed magnetization levels, the system continuously optimizes the magnetization state to match the instantaneous torque demand, thereby reducing unnecessary magnetization changes and associated energy losses while maintaining required torque output for vehicle acceleration.
2Speed
If the ideal magnetization state changes at high frequency, then the torque response is improved, but the number of magnetization changes becomes large causing significant losses
Solution Approach 1:
The controller acts as an intermediary between the torque demand signal and the magnetization control system. It processes the ideal magnetization state signal through filtering and smoothing algorithms that eliminate high-frequency components while preserving the essential torque response characteristics. This intermediary processing reduces the frequency of magnetization changes without significantly compromising torque response performance.
3Measurement precision
If the magnetization level is adjusted frequently to track ideal M/S, then the torque accuracy is improved, but steady state errors occur when ideal M/S settles between discrete values
Solution Approach 1:
The controller uses discrete magnetization levels that may not exactly match the ideal continuous M/S value. When the ideal M/S settles between two discrete values, the system selects the nearest available discrete level rather than attempting to achieve the exact ideal value. This partial action approach accepts a small deviation from the ideal M/S to eliminate steady-state errors and stabilize the system at discrete operating points.
4Device complexity
If discrete magnetization levels are predetermined based on stator flux linkage, then the control complexity is reduced, but steady state errors occur and efficiency is not maximized
Solution Approach 1:
The system uses a dynamic control strategy that continuously adjusts the magnetization level selection based on real-time operating conditions. Instead of relying on fixed predetermined magnetization levels, the controller dynamically determines the optimal discrete magnetization level by comparing the ideal M/S signal with available discrete options and selecting the best match. This dynamic approach maintains simplicity by using discrete levels while improving efficiency by optimizing the selection process.
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 reduces the number of magnetization changes by half and decreases driving losses by 24%, while maintaining efficient torque control and minimizing energy loss.
Implementation Method 1
a proportional-integral compensator (128) that is configured to receive an error signal representing the error value and remove a steady state error from the error signal
Implementation Method 2
the hysteresis control component comprises a sample and hold component (120) that is configured to output the actual magnetization state signal and to modify the actual magnetization state signal in accordance with the error value
Data Source
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AI summary
A variable magnetization machine controller (100) including a hysteresis control component configured to receive an ideal magnetization state signal, output an actual magnetization signal based on the ideal magnetization state signal for control of a variable magnetization machine (10), and modify the actual magnetization state signal in accordance with an error value between the ideal magnetization state signal and the actual magnetization state signal.