Electric Motor Mode Switching for Battery-Aware Torque Efficiency
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Solution Overview
Problem
Pulsing electric motors to increase efficiency in low torque ranges can lead to decreased overall system efficiency due to reduced battery efficiency, as the gains in motor efficiency are often offset or surpassed by increased battery losses.
Innovation Solution
A method to optimize system efficiency by calculating pulsed system efficiency and continuous system efficiency, and switching the electric motor to a pulsed mode only when the pulsed efficiency is greater, using a controller to determine the most efficient mode based on battery and motor efficiencies, and accounting for factors like heat dissipation and terminal voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the electric motor is pulsed to increase motor efficiency in low torque ranges, then motor efficiency is improved, but battery efficiency decreases
Solution Approach 1:
The system dynamically changes operating parameters by calculating and comparing pulsed system efficiency versus continuous system efficiency. The controller adjusts the duty cycle and pulsing frequency based on real-time efficiency calculations, switching between pulsed and continuous modes to optimize overall system efficiency while accounting for battery losses.
2Loss of energy
If the electric motor operates in continuous mode, then battery efficiency is maintained, but motor efficiency is low in low torque ranges
Solution Approach 1:
The system implements dynamic operation by continuously monitoring torque requirements and calculating efficiency metrics. The controller transitions between continuous and pulsed modes based on real-time conditions, allowing the motor to operate dynamically at optimal efficiency points while meeting varying torque demands.
3Use of energy by moving object
If the electric motor is pulsed at high duty cycle, then motor efficiency is maintained, but system efficiency decreases due to battery losses
Solution Approach 1:
The system employs feedback control by calculating pulsed system efficiency and continuous system efficiency, then comparing these values to determine the optimal operating mode. The controller uses this efficiency comparison feedback to switch between pulsed and continuous modes, ensuring overall system efficiency is maximized while maintaining motor performance.
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 ensures that increasing motor efficiency does not compromise overall system efficiency by selectively using pulsed mode only when it provides a net gain, thereby maintaining or improving system efficiency across both motor and battery components.
Implementation Method 1
determining the pulsed battery efficiency at least partially based on a dissipation heat loss of the battery
Data Source
AI summary
A method of controlling an electric motor to optimize system efficiency of an electric motor operable in a pulsed mode and a continuous mode is disclosed herein. The method includes receiving a requested torque for the electric motor, calculating a pulsed system efficiency, calculating a continuous system efficiency, and operating the electric motor in the pulsed mode when the pulsed system efficiency is greater than the continuous system efficiency. The pulsed system efficiency is calculated for delivering the requested torque from the electric motor in a plurality of torque pulses greater than the requested torque. The continuous system efficiency is calculated for delivering the requested torque from the electric motor as a continuous torque. The system efficiency may be at least partially based on a battery efficiency and a motor efficiency.