Hybrid Vehicle Vibration Control Using Walsh-Based Discrete Fourier Transform
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Solution Overview
Problem
Conventional frequency analysis methods for hybrid electric vehicles fail to clearly distinguish engine vibrations from noise components, leading to excessive vibration suppression control that negatively affects control efficiency and energy management, and are unable to actively control vibrations across various frequency components.
Innovation Solution
The method employs Walsh-based Discrete Fourier Transform (WDFT) to reduce the calculation load of the controller, select control target frequencies, and generate reference signals for efficient vibration control, including compensating the inverse phase torque based on engine acceleration to reduce fuel consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional frequency analysis using bandpass filter is used, then vibration component can be extracted, but engine vibration and noise component cannot be clearly divided leading to excessive vibration suppression control
Solution Approach 1:
The patent changes the fundamental parameter of frequency analysis from conventional bandpass filtering to Walsh-based Discrete Fourier Transform (WDFT). This parameter change enables clear separation of engine vibration components from noise components by utilizing Walsh functions that are synchronized with engine rotation, achieving both accurate vibration extraction and appropriate control intensity.
Solution Approach 2:
The patent replaces the mechanical filtering approach (bandpass filter) with a mathematical transformation approach (WDFT). This substitution allows for more precise identification of vibration components by transforming the signal into the frequency domain using Walsh functions, enabling clear distinction between actual engine vibrations and noise components.
2Object-affected harmful factors
If conventional frequency analysis is used, then vibration suppression can be performed, but active vibration control of other frequency components cannot be performed
Solution Approach 1:
The patent makes the vibration control system universal by enabling it to handle multiple frequency components simultaneously. The WDFT method generates reference signals for various frequency components (fundamental frequency, harmonics, etc.), allowing the system to actively control vibrations across the entire frequency spectrum rather than being limited to a single frequency band.
Solution Approach 2:
The patent introduces dynamics to the vibration control system by enabling adaptive selection and control of multiple frequency components. The system can dynamically adjust which frequency components to target based on real-time engine operating conditions, making the control strategy flexible and adaptable to varying vibration characteristics across different operating ranges.
3Productivity
If WDFT is used to select control target frequency, then calculation load is reduced, but control complexity increases
Solution Approach 1:
The patent extracts only the essential and most impactful frequency components for control using WDFT. Instead of attempting to control all frequency components or using computationally intensive methods, the system identifies and extracts the dominant vibration frequencies (such as fundamental frequency and key harmonics) that contribute most to engine vibration, thereby reducing calculation load while maintaining control effectiveness.
Data Source
AI summary
Disclosed are a method of and an apparatus for controlling a vibration of a hybrid electric vehicle. An apparatus for controlling a vibration of a hybrid electric vehicle may include: an engine position detector detecting a position of an engine; an air amount detector detecting an air amount flowing into the engine; an accelerator pedal position detector detecting a position of an accelerator pedal; a vehicle speed detector detecting a speed of the hybrid electric vehicle; and a controller. The controller controls operation of a motor based on the position of the engine, the air amount, the position of the accelerator pedal, and the speed of the hybrid electric vehicle.