Non-contact Power Transmission Positioning via Vehicle Speed Integration
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Solution Overview
Problem
Existing non-contact power transmission systems for vehicle charging lack accurate detection of the two-dimensional current position of the power reception unit relative to the power transmission unit, leading to inefficient alignment and potential discomfort for occupants due to inverse display of power transmission units and suboptimal power reception efficiency during main charging.
Innovation Solution
A non-contact power transmission system that includes a charging station with a power transmission unit and a vehicle with a power reception unit, utilizing a control unit with a voltage value detection unit, storage of voltage characteristics, and a moving amount detection unit to calculate the two-dimensional position of the power reception unit relative to the power transmission unit using weak power for precise alignment, thereby optimizing positioning and reducing electromagnetic interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If simple distance detection based on power reception voltage is used, then power saving and EMI suppression are achieved during positioning, but two-dimensional position detection accuracy deteriorates leading to misalignment
Solution Approach 1:
The positioning process is segmented into two distinct phases: a weak power phase for initial approach and rough positioning, and a strong power phase for precise two-dimensional alignment. This segmentation allows the system to use minimal power during the majority of the positioning journey while reserving higher power transmission only for the final alignment stage where precision is critical.
Solution Approach 2:
The system performs preliminary positioning using weak power transmission before transitioning to strong power transmission for fine alignment. This preliminary action brings the vehicle into proximity with the charging station, reducing the subsequent distance that requires high-power transmission and thereby optimizing overall energy consumption while ensuring final positioning accuracy.
2Object-affected harmful factors
If weak power transmission is used for positioning, then electromagnetic interference is suppressed, but positioning accuracy and power reception efficiency deteriorate
Solution Approach 1:
The power transmission system dynamically adjusts its output based on the positioning stage. The control unit monitors the vehicle's approach and automatically transitions from weak power transmission during initial positioning to strong power transmission during final alignment. This dynamic adjustment suppresses EMI during most of the positioning process while ensuring sufficient signal strength for accurate final positioning.
Solution Approach 2:
The system employs periodic assessment of the vehicle's position relative to the charging station, transitioning between weak and strong power modes at appropriate intervals. This periodic switching allows the system to maintain low EMI levels during approach while periodically enhancing power transmission to confirm and refine positioning accuracy before completing the alignment.
3Speed
If positioning is terminated when power reception voltage exceeds threshold, then positioning speed is improved, but power reception efficiency during main charging deteriorates
Solution Approach 1:
The system replaces simple voltage threshold detection with a sophisticated control mechanism that continuously monitors multiple parameters including power reception voltage, vehicle position, and alignment status. This substitution of the basic mechanical threshold system with an intelligent control system enables both rapid positioning and optimized power reception efficiency by determining the optimal transition point from positioning to charging mode.
Solution Approach 2:
The control unit implements feedback mechanisms that continuously monitor power reception characteristics during the transition from positioning to charging. This feedback allows the system to adjust the transition timing to optimize power reception efficiency, ensuring that the vehicle is optimally positioned before initiating main charging, thereby avoiding energy waste while maintaining fast positioning speed.
4Measurement precision
If two-dimensional position detection is implemented, then alignment accuracy is improved, but device complexity increases
Solution Approach 1:
The control unit serves multiple functions: it manages power transmission switching between weak and strong modes, detects vehicle approach, determines positioning completion, and optimizes the transition to charging mode. By making the control unit universal and multi-functional, the system achieves two-dimensional position detection and precise alignment without adding separate dedicated hardware components, thereby minimizing device complexity while maintaining high alignment accuracy.
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 system accurately detects the two-dimensional position of the power reception unit, ensuring optimal alignment and efficient power transfer during charging, while minimizing power waste and electromagnetic interference.
Implementation Method 1
a power transmission unit (11) configured to transmit a certain transmission power in a radial direction, and a power reception unit (12) configured to receive a power in accordance with the transmission power without contact
Data Source
AI summary
Based on a vehicle speed Vv, a vehicle moving amount cvp is calculated from cvp=∫Vv·dt. From the Pythagorean theorem, expressions y2+x2=ra2 and y2+(cb−x)2=cvp2 are held. From these two expressions, an ECU of a non-contact power transmission system obtains x and y. In the expressions, y is a distance in a horizontal direction from a power transmission coil, x is a distance in a vertical direction from the power transmission coil, and ra is a distance from the power transmission coil at a two-dimensional current position and is obtained in advance from a correspondence relation between the distance and the intensity of a power transmitted from the power transmission coil.