Electric Drive Switching Frequency Control for Psychoacoustic Noise
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Electric drive systems, such as those in electric vehicles, face challenges in noise emission due to varying switching frequencies in power converters, which can lead to psycho-acoustic irritations as they do not adapt to the operating behavior of the drive system, such as changes in rotational speed or torque.
Innovation Solution
A control device and method that monitor the rotational frequency and torque of an electrical machine to define a control range for the switching frequency of a power converter, ensuring the noise generation aligns with the drive system's operating behavior by adjusting the switching frequency within specific limits, thereby minimizing irritations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the switching frequency is varied to optimize electrical losses and voltage ripple, then energy efficiency is improved, but noise emission increases and causes psycho-acoustic irritations
Solution Approach 1:
The switching frequency is made dynamic rather than fixed, allowing it to adapt to current operating conditions. The control unit continuously adjusts the switching frequency within a control range based on monitored rotational frequency and torque variations, optimizing energy efficiency while managing noise emissions through adaptive control.
Solution Approach 2:
The patent changes the switching frequency parameter dynamically based on operating conditions. By monitoring rotational frequency and torque variations, the system adjusts the switching frequency to optimize electrical losses and voltage ripple while staying within acceptable noise emission limits.
2Reliability
If the switching frequency is adjusted to reduce voltage ripple, then power quality is improved, but noise generation increases and affects driver perception
Solution Approach 1:
The system implements feedback control by monitoring the rotational frequency and torque of the electrical machine, then using this information to adjust the switching frequency. This closed-loop control ensures that voltage ripple is reduced while keeping noise generation within acceptable limits by continuously adapting to operating conditions.
Solution Approach 2:
The switching frequency is dynamically adjusted based on real-time operating conditions rather than being fixed. The control unit responds to changes in rotational frequency and torque by modifying the switching frequency within a defined control range, balancing voltage ripple reduction with noise control.
3Device complexity
If a fixed switching frequency is used, then control simplicity is maintained, but the system cannot adapt to varying operating conditions leading to increased noise irritations
Solution Approach 1:
The system transitions from a fixed switching frequency to a dynamic control approach where the switching frequency adapts to operating conditions. The control unit monitors rotational frequency and torque variations and adjusts the switching frequency accordingly, providing adaptability while maintaining manageable control complexity through structured control logic.
Data Source
AI summary
The invention relates to controlling an electric drive system, a control range for the switching frequency of a power converter in such a drive system being adaptable when the rotational frequency curve or the torque curve of the electrical machine is taken into account. In this way, psycho-acoustic irritations can be avoided.