Permanent Magnet Motor Inverter Switching at Zero Torque
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Solution Overview
Problem
In electric vehicles, permanent magnet motors experience inefficiencies due to continuous toggling of transistors, which generates energy loss in the form of heat, especially when zero motor torque is demanded, affecting the vehicle's energy efficiency and driving range.
Innovation Solution
A method and system where a motor controller in a permanent magnet motor ceases the toggling of transistors when the torque command is within a predefined margin of zero torque and the motor speed is below a certain base speed, using torque command arbitration and sensors to determine when to initiate or cease transistor toggling, thereby reducing energy loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If transistors continue to toggle in the inverter, then the motor can respond to torque commands and maintain operational control, but energy is lost as heat reducing overall system efficiency
Solution Approach 1:
The patent applies periodic action by implementing conditional transistor toggling based on torque command thresholds and speed ranges. Transistors toggle periodically only when torque demand exceeds a threshold and motor speed is within a specific range, rather than continuously. This periodic operation eliminates unnecessary switching cycles that cause energy loss while maintaining motor control reliability when actually needed.
Solution Approach 2:
The patent changes operational parameters (transistor switching state) based on varying operating conditions (torque command magnitude and motor speed). By monitoring these parameters and adjusting transistor toggling accordingly - ceasing toggling when torque is near zero and speed is in the base speed range - the system optimizes energy efficiency while preserving motor control capability when required.
2Loss of energy
If transistor toggling is ceased to reduce energy loss, then energy efficiency improves, but the motor may fail to respond to torque demands
Solution Approach 1:
The patent implements dynamics by making transistor toggling behavior adaptive to real-time operating conditions. The system dynamically adjusts between toggling and non-toggling states based on torque command thresholds and motor speed ranges. This dynamic response ensures torque delivery capability is maintained when needed while eliminating unnecessary energy loss during idle or low-demand conditions.
Solution Approach 2:
The patent uses feedback mechanisms by continuously monitoring torque commands and motor speed to determine when transistor toggling should be active or ceased. This feedback loop ensures that toggling is maintained when torque response is needed while being stopped when torque demand is near zero, thus preserving productivity while reducing energy loss.
3Reliability
If transistors are toggled continuously, then the motor maintains readiness to deliver torque, but heat generation increases reducing driving range
Solution Approach 1:
The patent applies periodic action by implementing conditional transistor toggling based on torque command thresholds and speed ranges. Transistors toggle periodically only when torque demand exceeds a threshold and motor speed is within a specific range, rather than continuously. This periodic operation eliminates unnecessary switching cycles that cause energy loss while maintaining motor control reliability when actually needed.
Solution Approach 2:
The patent changes operational parameters (transistor switching state) based on varying operating conditions (torque command magnitude and motor speed). By monitoring these parameters and adjusting transistor toggling accordingly - ceasing toggling when torque is near zero and speed is in the base speed range - the system optimizes energy efficiency while preserving motor control capability when required.
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 energy loss and improves the efficiency of the permanent magnet motor by minimizing transistor toggling when zero torque is required, enhancing the electric vehicle's energy efficiency and driving range.
Implementation Method 1
determining a present base speed of the permanent magnet motor based on voltage and back electromotive force
Data Source
AI summary
A method comprises: receiving, by a motor controller, a torque command for a permanent magnet motor of an electric vehicle, wherein the permanent magnet motor is coupled to an inverter having transistors, and wherein the permanent magnet motor has a present speed; determining a present base speed of the permanent magnet motor; and in response to the torque command meeting a zero-torque criterion while the present speed meets a below-base-speed criterion, ceasing, by the motor controller, a toggling of the transistors so that the transistors are nonconductive.