Inductive Power Transfer Coil Array for Multi-Device Charging
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Solution Overview
Problem
Existing inductive power transfer (IPT) systems for consumer electronic devices face inefficiencies due to the need for precise alignment of coils, non-uniform magnetic fields leading to 'weak spots', and challenges in detecting and powering multiple devices simultaneously while avoiding parasitic loads.
Innovation Solution
A system with a power transmitter having multiple coils and a controller that detects characteristics of the receiver to control power transfer modes, including object detection and communication through modulated power signals to optimize coil usage and ensure compatibility, allowing for efficient and safe multi-device charging with spatial freedom.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single large transmitting coil is used to cover the entire charging mat surface, then device placement freedom is improved, but magnetic field uniformity deteriorates with weak spots towards the centre
Solution Approach 1:
The charging mat is divided into multiple smaller transmitting coils arranged in an array rather than using a single large coil. Each coil can be independently controlled and activated based on device position, providing both field uniformity at each coil location and overall placement freedom across the entire mat surface.
Solution Approach 2:
The system dynamically selects and activates specific transmitting coils based on real-time detection of device position and characteristics. This dynamic adaptation allows the system to maintain optimal magnetic field uniformity by activating only the coils nearest to devices, while still providing placement freedom across the entire charging surface.
2Stability of the object's composition
If an array of smaller transmitting coils is used, then magnetic field uniformity is improved, but device placement freedom deteriorates due to boundary effects and weak spots between coils
Solution Approach 1:
Multiple transmitting coils are activated simultaneously to collectively power multiple devices placed at different locations on the charging mat. The system merges the output of several coils to provide comprehensive coverage, eliminating weak spots between individual coils and maintaining both field uniformity and placement freedom.
Solution Approach 2:
The system dynamically determines which coils to activate based on device positions, ensuring that devices near boundaries are powered by the nearest active coils while maintaining sufficient power transfer efficiency. This dynamic coil selection resolves the placement freedom issue by adapting to any device location on the mat.
3Loss of energy
If precise alignment between transmitting and receiving coils is required, then power transfer efficiency is improved, but ease of operation deteriorates as users must carefully place devices
Solution Approach 1:
The charging mat uses multiple smaller transmitting coils instead of a single large coil, allowing the system to activate only the coil closest to each device. This segmentation enables efficient power transfer without requiring precise user alignment, as each coil independently serves devices in its local area.
Solution Approach 2:
The system automatically detects device position and activates the appropriate transmitting coils without user intervention. The self-aligning capability eliminates the need for users to carefully position devices, maintaining high power transfer efficiency while dramatically improving ease of operation.
4Adaptability or versatility
If the entire charging mat surface is powered, then device placement freedom is improved, but safety deteriorates due to potential hazards from unattended powered areas
Solution Approach 1:
The charging mat divides the powered area into discrete, independently controllable coil segments. Only the coils with detected devices are activated, while other areas remain unpowered. This provides placement freedom within active zones while eliminating safety hazards in inactive areas.
Solution Approach 2:
The system dynamically adjusts the powered areas by activating only those transmitting coils that have detected compatible devices. This dynamic power distribution maintains placement freedom for devices while automatically deactivating areas without devices, preventing safety hazards from parasitic loads in unattended zones.
5Object-affected harmful factors
If a manually operated power switch is added to control transmitter power, then safety is improved by preventing parasitic load heating, but ease of operation deteriorates and convenience is reduced
Solution Approach 1:
The system automatically detects the presence or absence of devices and activates or deactivates transmitting coils accordingly, without requiring manual user intervention. This self-service capability maintains safety by preventing parasitic load heating while preserving system convenience through automatic operation.
Solution Approach 2:
The system continuously monitors device presence and provides feedback control for power transmission. When devices are detected, power is activated; when devices are removed, power is deactivated. This feedback mechanism automatically prevents parasitic load heating while maintaining user convenience without manual switches.
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 achieves reliable and efficient wireless power transfer for multiple devices with improved alignment flexibility and safety by selectively controlling transmitter coils based on receiver characteristics, reducing energy loss and preventing overheating from parasitic loads.
Implementation Method 1
The transmitter drives the transmitting coils so that the transmitting coils generate a time-varying magnetic field in the immediate vicinity of the planar surface. When portable electronic devices are placed on or near the planar surface, the time-varying magnetic field will induce an alternating current in the receiving coil of a suitable receiver associated with the device
Data Source
AI summary
A system for inductive power transfer that may selectively transmit power in a plurality of modes based on characteristics of a power receiver and determine which transmitter coils to drive based on received signal strength information. The inductive power transfer transmitter may detect characteristics of the power receiver in order to control the mode of the power transfer and selectively control which transmitter coils are driven based on signal strength information received from a power receiver. The power transmitter may have slugs formed of a magnetically permeable material within common coil winding openings and the transmitter coils may consists of a plurality of parallel windings.