Hybrid Vehicle Vibration Control Using Walsh-Based DFT
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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 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 calculate engine speed, set reference angles, and select control target frequencies, generating a reference signal to control motor operations, thereby reducing calculation loads and improving vibration control efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional frequency analysis using bandpass filter is used, then vibration component can be extracted based on magnitude of each point in frequency band, but unique vibration component of engine and noise component are not clearly divided leading to excessive vibration suppression control
Solution Approach 1:
The patent extracts only the significant vibration components exceeding a threshold value from the frequency spectrum, separating them from noise components. This selective extraction of dominant vibration frequencies enables precise identification of engine vibration components without being contaminated by noise, thereby improving both measurement precision and control reliability.
Solution Approach 2:
The patent changes the control parameters by using identified significant vibration frequencies as target frequencies for active vibration control. By dynamically adjusting the control parameters based on the extracted vibration characteristics, the system achieves reliable vibration suppression without excessive control actions, improving both accuracy and reliability.
2Measurement precision
If reference signal is generated only in specific frequency component, then synchronization signal synchronized with vibration signal can be generated, but active vibration control of other frequency components cannot be performed
Solution Approach 1:
The patent generates multiple reference signals corresponding to different significant vibration frequencies simultaneously. This multi-functional approach allows the vibration control system to handle multiple frequency components at once, making the system versatile enough to control various vibration modes while maintaining synchronization accuracy for each frequency component.
Solution Approach 2:
The patent segments the vibration control into multiple independent frequency components, each with its own reference signal and control strategy. By dividing the overall vibration control task into separate frequency-specific sub-tasks, the system achieves both precise synchronization for each component and comprehensive coverage across all significant vibration frequencies.
3Productivity
If Walsh-based Discrete Fourier Transform is used, then calculation load of controller is reduced, but system complexity increases due to transform algorithm
Solution Approach 1:
The patent replaces the conventional Fast Fourier Transform (FFT) algorithm with Walsh-based Discrete Fourier Transform. This substitution uses Walsh functions instead of complex exponential functions, eliminating the need for complex arithmetic operations and significantly reducing the calculation load on the controller while achieving the same frequency analysis objective.
Data Source
AI summary
Disclosed are a method of and an apparatus for controlling a vibration of a hybrid electric vehicle. An apparatus of controlling a vibration of a hybrid electric vehicle disclosure 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; an SOC detector detecting a state of charge (SOC) of a battery; and a controller. The controller controls the operation of a motor based of the position of the engine, the air amount, the position of the accelerator pedal, the speed of the hybrid electric vehicle, and the SOC of the battery.