Electric Motor Noise Modulation via Current Component Control
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Solution Overview
Problem
Existing noise modulation methods for electric motors in vehicles, such as those used in power-assisted steering systems, either significantly affect the rotational speed and torque output or require costly secondary measures, which compromise lightweight construction and rigidity, and fail to enhance vehicle perceptibility in urban traffic due to low noise emission.
Innovation Solution
A method for noise modulation of multiphase synchronous motors using vector regulation, where actual current components are compared to reference variables and adjusted via a regulator and transformation stages to minimize torque impact, allowing for targeted acoustic state modulation through a PWM generator, with acoustic regulators converting deviations into duty cycles to achieve desired noise levels without substantial rotational speed or torque fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If conventional secondary measures are used to handle acoustic problems, then noise is reduced, but system weight increases and rigidity decreases
Solution Approach 1:
The patent replaces mechanical noise reduction measures (such as acoustic insulation, damping materials, and structural modifications) with an electronic control system that modulates the motor's magnetic field to actively reduce noise. The motor control unit adjusts current components id and iq based on acoustic measurements, eliminating the need for additional mechanical noise-reduction components and preserving lightweight construction.
2Object-generated harmful factors
If pulse width modulation is used to convert interfering noises into musical intervals, then noise is transformed, but rotational speed and torque output fluctuate
Solution Approach 1:
The patent changes the parameters of the current components id (magnetisation current) and iq (torque-forming current) in a controlled manner to modulate noise while maintaining constant rotational speed and torque output. The motor control unit calculates adjusted current values that compensate for noise-induced fluctuations, ensuring that the motor's mechanical output remains stable despite acoustic modulation.
3Loss of energy
If electric motors operate at low noise levels, then energy efficiency is improved, but vehicle perceptibility decreases
Solution Approach 1:
The patent employs periodic modulation of the motor's magnetic field to generate acoustic signals at specific frequencies and intervals. The motor control unit creates periodic variations in current components that produce audible noise patterns, enabling vehicle presence to be perceived while maintaining overall low noise operation and energy efficiency during normal driving conditions.
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 effectively generates specific noises, reduces operational noise, and can cancel other vehicle noises by phase-displaced emissions, maintaining minimal impact on torque output and rotational speed, thus enhancing vehicle perceptibility without additional hardware or complex measures.
Implementation Method 1
the magnetisation current-forming current component id is adapted, depending on an acoustic state that was measured by a measuring device and was transmitted by means of a signal output to the motor control unit
Implementation Method 2
the differences between the actual values and the reference variables are converted via a first regulator and a first transformation stage in a duty cycle for a PWM generator into target variables
Implementation Method 3
The radial magnetic field components of the electric motor lead to a cyclical deformation of the motor, which causes an acoustic radiation
Data Source
AI summary
A method for the noise modulation of a three-phase synchronous electric motor driven using a vector regulation by means of a motor control unit. Actual values for the rotated current components id and iq may be obtained in an open-loop control system, where id corresponds to the magnetization current and iq corresponds to the torque-forming current of the synchronous motor. The actual values may be compared with predetermined reference target values, and the differences between the actual values and the reference target values may be converted into control variables to regulate the actual values (iq, id) to the reference target values. The magnetization current-forming current component (id) may be adapted using an acoustic controller to a desired acoustic state depending on an acoustic state that was measured by a measuring device and was transmitted to the motor control unit.