Electric Traction Machine Heat Control via Current Ratio
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Solution Overview
Problem
Existing methods for controlling dissipated heat in electric traction machines of motor vehicles often impair the acoustics due to magnetically excited noise, which is perceived as annoying by vehicle passengers.
Innovation Solution
A method and electric drive unit that control the dissipated heat by adjusting the ratio of field-forming and torque-forming currents, while additionally setting a rotor current in a magnet-less three-phase machine to minimize acoustic noise signals, allowing for the provision of a predetermined amount of dissipated heat without generating interference signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the ratio of field-forming current and torque-forming current is adjusted to control dissipated heat, then the amount of dissipated heat can be increased for heating purposes, but magnetically excited noise increases and acoustics are impaired
Solution Approach 1:
The patent applies parameter changes by adjusting the ratio of field-forming current to torque-forming current to control the amount of dissipated heat. By varying these current parameters, the system can provide predetermined amounts of heat for heating the vehicle interior or battery while operating the electric traction machine, thus resolving the contradiction between generating useful heat and avoiding excessive noise.
2Temperature
If additional heating devices are used to provide heat, then the heating requirement is met, but device complexity and cost increase
Solution Approach 1:
The patent applies universality by enabling the electric traction machine to serve multiple functions: propulsion and heat generation. By controlling the current ratio, the traction machine can provide heat for the vehicle interior or battery heating requirements, eliminating the need for separate heating devices and reducing overall system complexity.
Solution Approach 2:
The patent applies self-service by using the electric traction machine's own operational characteristics to generate heat. The system utilizes the inherent electrical losses and controlled current ratios during normal operation to provide heating, making the traction machine self-sufficient for both propulsion and thermal management needs.
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 optimizes the acoustics of the electric traction machine by minimizing noise while maintaining the necessary dissipated heat for temperature control, potentially eliminating the need for additional heating devices and improving the overall acoustic experience for passengers.
Implementation Method 1
controlling an amount of dissipated heat in an electric traction machine (2) of a motor vehicle (1)
Data Source
AI summary
An electric traction machine, a motor vehicle, and a method for controlling dissipated heat in the electrical power plant of the motor vehicle are described herein. The power plant is supplied with a current, where, in order to provide a predetermined amount of dissipated heat, a ratio between a field-forming and a torque-forming current deviating from an optimum ratio for a respective operating point of the power plant is prescribed. The predetermined dissipated heat is provided by a power plant embodied as a magnet-less three-phase alternator while a rotor current flowing through a rotor of the three-phase alternator is adjusted, the field-forming and the torque-forming currents being prescribed such that acoustic interference signals of the three-phase alternator are minimized by the ratio, and the rotor current is adjusted such that the predetermined dissipated heat is provided by a combination of the rotor current and the ratio minimizing the interference signals.