Electric Motor Beat Noise Control for EV Acceleration Sensation
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Solution Overview
Problem
Electric vehicles with electric motors lack the sensory experience of acceleration due to constant and unchanging operating noise, unlike internal combustion engine vehicles, which can be unpleasant during steady travel but fail to provide an engaging sound during acceleration.
Innovation Solution
An operating noise control device generates beat noise during vehicle acceleration by producing noise components closely aligned with the electric motor's rotation speed, enhancing the acceleration sensation while maintaining quietness during steady travel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the electric motor operates quietly during steady travel, then quietness is assured, but the driver cannot experience the acceleration sensation provided by engine noise
Solution Approach 1:
The patent applies periodic action by generating beat noise through intermittent modulation of the inverter output frequency. The control device periodically varies the frequency of the electric motor's operating noise to create beat patterns during acceleration, while maintaining quiet operation during steady travel. This periodic frequency modulation creates the desired acceleration sensation without compromising steady-state quietness.
2Ease of operation
If beat noise is generated during acceleration, then the acceleration sensation is enhanced, but unpleasant noise may occur during steady travel
Solution Approach 1:
The patent implements dynamics by making the beat noise generation conditional and adaptive. The control device dynamically adjusts the inverter output frequency based on the vehicle's operating state - generating beat noise patterns during acceleration to enhance sensation, while suppressing such patterns during steady travel to avoid unpleasant noise. This dynamic control ensures the noise characteristics adapt to the current driving condition.
Solution Approach 2:
The patent applies local quality by creating different noise characteristics for different operating conditions. Instead of uniform noise control, the system generates beat noise specifically during acceleration phases while maintaining quiet operation during steady travel. This localized approach to noise generation ensures the acceleration sensation is enhanced only when needed, without introducing unpleasant noise during normal cruising.
3Object-affected harmful factors
If the operating noise frequency is adjusted to prevent beat noise, then quiet operation is maintained, but the acceleration sensation is reduced
Solution Approach 1:
The patent resolves this contradiction by introducing periodic frequency modulation during acceleration. Instead of maintaining a fixed frequency that suppresses beat noise, the control device periodically varies the output frequency to create beat patterns. This periodic action generates the desired acceleration sensation while the frequency variation is carefully controlled to prevent excessive beat noise during steady travel 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
The device creates a thrilling acceleration sound without inducing unpleasant noise or vibration, improving the driving experience by generating beat noise exclusively during acceleration and suppressing it during steady travel.
Implementation Method 1
generating operating noise containing a component, the order of which is very close to an operating noise generation order that is in proportion to a rotation speed of the electric motor
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A vehicle (1, 17) includes an electric drive motor (5, 19), an inverter (4) that provides a drive current to the electric motor (5, 19) and a controller (13) that controls the inverter (4). The controller (13) functions as a beat noise generation system that creates beat noise by generating a second operating noise containing a component an order of which is very close to a value representing an order of an operating noise generated in proportion to a rotation speed of the electric motor (5, 19) so as to create desirable traveling noise corresponding to an accelerating state while the vehicle accelerates.