Electric Motor Current Oscillation for In-Drive Heat Generation
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Solution Overview
Problem
Existing methods for heat generation in vehicles using electrical motors are inefficient and limited in accessibility during driving, particularly affecting vehicles with redundant heating devices.
Innovation Solution
A computer system that controls electrical machines in vehicles to oscillate d and q currents between specific current values, maintaining a reference torque, to generate heat efficiently, even during normal operation, by using the electrical machine's existing components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If electrical motor is used for heat generation, then heating function is provided, but efficiency is poor and accessibility during driving is limited
Solution Approach 1:
The patent applies periodic action by oscillating the d and q currents between specific values while maintaining the reference torque. This oscillating current pattern generates heat in the electrical machine components (stator, rotor, magnets) during normal driving operation, making heat generation accessible whenever the motor is running without requiring separate heating cycles or modes.
Solution Approach 2:
The patent changes the electrical parameters (d and q current values) to achieve heat generation. By varying the current oscillation amplitude and frequency while maintaining constant torque output, the system can control the amount of heat generated in different components, optimizing both efficiency and accessibility during driving.
2Adaptability or versatility
If multiple heating devices are provided in vehicle, then heating coverage is improved, but production cost increases
Solution Approach 1:
The patent makes the electrical motor multi-functional by enabling it to perform both its primary function (producing torque for vehicle propulsion) and a secondary function (generating heat for cabin, engine block, or exhaust heating). This eliminates the need for separate dedicated heating devices, reducing vehicle complexity and production costs while maintaining comprehensive heating coverage.
Solution Approach 2:
The electrical machine serves itself by generating its own heat during normal operation through controlled current oscillation. The heat generated within the motor components is utilized for vehicle heating needs, eliminating the need for external or separate heating systems and reducing overall system complexity.
3Loss of energy
If d and q currents are oscillated to generate heat, then heat generation efficiency is improved, but torque control precision must be maintained
Solution Approach 1:
The patent employs feedback control by continuously monitoring the actual torque output and adjusting the oscillating d and q currents to maintain the reference torque. The control system ensures that despite the current oscillation used for heat generation, the net torque produced matches the desired reference torque, maintaining precision while achieving efficient heat generation.
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 method allows for controlled heat generation in the electrical machine, reducing the need for additional heating devices and ensuring efficient heat production even at higher speeds.
Implementation Method 1
produce heat in the electrical machine by oscillating the d and q currents between the first and second set of current values while maintaining the reference torque
Implementation Method 2
A computer system and method for heat generation... obtain a maximum achievable flux linkage of an electrical machine... produce heat in the electrical machine by oscillating the d and q currents
Implementation Method 3
a pulsating field in the rotor will heat the magnets of the electrical machine. This is especially important when dealing with permanent magnet materials that easily demagnetize at cold temperatures
Data Source
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AI summary
A computer system comprising processing circuitry configured to: obtain a maximum achievable flux linkage (ψ̂) of an electrical machine (10), obtain a reference torque ( Tcrop∗) of the electrical machine (10) based on the maximum achievable flux linkage (ψ̂), obtain a first set of d and q current values (Idmax, Iqmax) resulting in the reference torque ( Tcrop∗), obtain a second set of d and q current values (Idmin, Iqmin) resulting the reference torque ( Tcrop∗), and produce heat in the electrical machine (10) by oscillating the d and q currents between the first and second set of current values (Idmax, Iqmax, Idmin, Iqmin) while maintaining the reference torque ( Tcrop∗).