Wireless Charging Pad With Segmented Coils for Power Loss Reduction
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Solution Overview
Problem
Existing wireless charging pads face limitations in mobility, power loss, and the number of chargeable devices due to their fixed size and inefficient coil driving configurations, which restrict their use in complex environments like homes, offices, and public transportation.
Innovation Solution
A wireless charging system with a plurality of small power transmission coils arranged in a tessellation structure, driven by a controller that applies phase-specific voltages to only the coils under and surrounding the charging devices, reducing power dissipation and allowing for modular expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a large area wireless charging pad with fixed coils is used, then charging coverage area is improved, but power loss increases and mobility is limited
Solution Approach 1:
The wireless charging pad is divided into multiple independent small power transmission coils arranged in a tessellation structure. Each coil can be independently controlled to activate only the coils needed for current charging demand, reducing power consumption in unused areas while maintaining large coverage capability.
Solution Approach 2:
The system dynamically selects and activates specific coils based on real-time charging requirements. The controller can turn individual coils on or off, allowing the charging area to be dynamically adjusted to match the actual number and position of devices being charged, thereby minimizing power loss.
2Productivity
If all coils in the wireless charging pad are driven simultaneously, then charging capacity for multiple devices is improved, but power consumption increases
Solution Approach 1:
Different regions of the charging pad have different coil activation states based on local charging needs. The controller applies phase-specific voltages to coils under and surrounding charging devices, creating localized charging zones rather than uniformly activating all coils, thus optimizing power consumption relative to actual charging demand.
Solution Approach 2:
The system activates only the necessary subset of coils required for current charging operations rather than all coils. By using partial action (activating only needed coils) and phase-specific voltage application, the system achieves sufficient charging capacity while minimizing unnecessary power consumption.
3Length of stationary object
If magnetic field resonance method is used for medium-distance transmission, then transmission distance is improved, but magnetic field spread and potential harm to human body increase
Solution Approach 1:
The magnetic field transmission is segmented into multiple small independent coils rather than using a single large resonant coil. This segmentation allows for localized magnetic field generation, reducing overall magnetic field spread while maintaining effective transmission distance to devices on the charging pad surface.
Solution Approach 2:
The system uses phase-specific voltage application to coils surrounding the target coil to cancel out or reduce magnetic field spread to surrounding areas. By strategically controlling the phase of adjacent coils, the harmful magnetic field radiation is minimized while maintaining the beneficial medium-distance transmission capability.
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
This solution enhances charging efficiency and mobility by minimizing power loss and magnetic field spread, enabling efficient charging in various environments and supporting multiple devices without additional control circuits.
Implementation Method 1
The magnetic induction method, as a contact-type wireless power transmission method which is currently used in wireless chargers
Implementation Method 2
A wireless power transmission system adopting magnetic field resonance has been actively studied since Marin Solajacic's MIT team first proposed the same in 2007. This system uses a resonance phenomenon during transmission and reception
Data Source
AI summary
Disclosed are a wireless charging pad including a plurality of small power transmission coils and a device for and a method of driving the wireless charging pad. More particularly, the wireless charging apparatus includes a driving controller configured to generate a first control signal so as to apply a first driving voltage having a first phase to power transmission coils to be driven matching a device to be charged among the small power transmission coils and generate a second control signal so as to apply a second driving voltage having a phase opposite to the first phase to power transmission coils surrounding the power transmission coils to be driven; and a coil driver configured to apply the first and second driving signals to a wireless charging pad.