Adaptive PWM Switching Frequency Control for Vehicle Cabin Noise Reduction
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Solution Overview
Problem
Existing methods for reducing pulse width modulation (PWM) noise in vehicle cabins, such as using higher switching frequencies, lead to power losses and increased costs, and are difficult to calibrate due to varying ambient noise conditions caused by driver behavior, road surfaces, and other factors.
Innovation Solution
A method that modulates PWM switching frequencies with perturbations and adjusts them based on in-cabin sound measurements to reduce noise emissions, allowing for automatic updates of the PWM scheme in response to changing acoustic conditions without sacrificing system efficiency or torque production accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If higher switching frequencies are used to reduce PWM noise, then noise reduction is improved, but power losses increase and fuel economy deteriorates
Solution Approach 1:
The patent applies dynamics by making the PWM switching frequency adjustable and adaptive rather than fixed. The system dynamically changes switching frequencies based on real-time acoustic measurements from microphones, allowing it to optimize between noise reduction and power efficiency depending on ambient conditions. This resolves the contradiction by enabling the system to use higher frequencies only when necessary for noise reduction while maintaining lower frequencies for power efficiency when ambient noise masks PWM sounds.
Solution Approach 2:
The patent changes the parameter of switching frequency from a static value to a dynamically adjustable parameter. By measuring acoustic conditions and adapting the switching frequency accordingly, the system can shift between frequency values to balance noise reduction and power consumption. This parameter change enables the system to resolve the contradiction between reducing PWM noise and minimizing power losses.
2Object-affected harmful factors
If higher switching frequencies are used to reduce PWM noise, then noise reduction is improved, but system costs increase
Solution Approach 1:
The system dynamically adjusts switching frequencies based on acoustic measurements, allowing it to achieve noise reduction only when necessary. This dynamic approach avoids the need for expensive hardware modifications, as it uses software-based frequency adaptation to resolve the contradiction between noise reduction and cost.
Solution Approach 2:
By changing the switching frequency parameter adaptively rather than using fixed high frequencies, the system achieves noise reduction without requiring expensive power circuit modifications. The parameter change approach allows the system to maintain cost-effectiveness while reducing PWM noise when ambient conditions permit.
3Device complexity
If fixed PWM switching frequencies are used, then system simplicity is maintained, but adaptability to varying ambient noise conditions deteriorates
Solution Approach 1:
The patent implements feedback by using microphones to measure acoustic conditions in real-time and using this information to adaptively adjust PWM switching frequencies. This feedback mechanism enables the system to automatically adapt to varying ambient noise conditions without requiring complex manual calibration, resolving the contradiction between simplicity and adaptability.
Solution Approach 2:
The system performs self-service by automatically measuring acoustic conditions and adjusting its own switching frequencies without external intervention. This self-adaptation capability allows the system to maintain simplicity while achieving high adaptability to varying ambient noise conditions through automated feedback-based frequency adjustment.
4Extent of automation
If manual calibration of PWM frequencies is used, then automation is reduced, but calibration precision may be improved, yet calibration difficulty increases due to varying ambient conditions
Solution Approach 1:
The patent uses feedback from acoustic measurements to automatically calibrate and adjust PWM switching frequencies. The system continuously monitors ambient noise conditions and adapts frequencies accordingly, eliminating the need for difficult manual calibration while maintaining precision through real-time measurement-based adjustment.
Solution Approach 2:
The system performs self-calibration by automatically measuring acoustic conditions and adjusting its own PWM parameters without human intervention. This self-service approach resolves the contradiction by making the system highly automated while simplifying the calibration process through automated feedback-based adaptation to varying ambient conditions.
Data Source
AI summary
Methods and systems are provided for adaptive pulse width modulated control of an electrified powertrain of a vehicle. In one example, a method may include perturbing a switching frequency for pulse width modulated control of the electrified powertrain, and, responsive to sound measured in a vehicle cabin indicating a noise improvement after the perturbation, controlling the electrified powertrain with the perturbed switching frequency. In this way, acoustic emissions from an electrified powertrain may be reduced.