Electrodynamic Wireless Power Transfer via Magnetic Oscillation
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Solution Overview
Problem
Inductive wireless power transfer systems face limitations in power levels and efficiency due to safety constraints on magnetic and electric fields, requiring high frequencies which lead to eddy current losses and inefficiencies, especially over longer distances and in applications involving conductive materials.
Innovation Solution
An electrodynamically coupled wireless power transfer system using a low-frequency, time-varying magnetic field to induce mechanical oscillations in a magnet, which is then converted into electrical power through electromechanical means, reducing exposure to strong magnetic fields and allowing smaller receiver coils and lower operating frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If high frequency is used in inductive wireless power transfer, then power transfer efficiency is improved, but eddy current losses increase and safety constraints are violated
Solution Approach 1:
The patent changes the operating frequency parameter from high frequency (RF range) to low frequency (audio range), which fundamentally alters the interaction mechanism with conductive materials. This parameter change reduces eddy current losses and magnetic field exposure while maintaining acceptable power transfer efficiency through optimized coil design and coupling mechanisms.
Solution Approach 2:
The patent replaces the traditional electromagnetic induction mechanism (which operates at high frequencies) with a low-frequency oscillating magnetic field mechanism. This substitution changes the fundamental physics of power transfer, allowing operation below the thresholds that cause significant eddy current losses and safety concerns while maintaining effective wireless power transmission.
2Power
If high frequency is used in inductive wireless power transfer, then power transfer capability is improved, but safety constraints on magnetic and electric fields are violated
Solution Approach 1:
The patent changes the operating frequency from high frequency to low frequency, which fundamentally alters the magnetic field characteristics. This parameter change allows achieving the required power transfer capability while keeping magnetic field exposure below safety thresholds, as low-frequency fields penetrate differently and induce less harmful effects in biological tissues.
Solution Approach 2:
The patent employs dynamic optimization of the low-frequency oscillating magnetic field, adjusting field strength, oscillation amplitude, and coupling conditions to achieve maximum power transfer within safety constraints. This dynamic approach allows the system to operate at the boundary of safety limits efficiently without violating regulatory requirements.
3Ease of operation
If traditional inductive coupling is used, then wireless power transfer is achieved, but receiver coil size must be large for adequate power reception
Solution Approach 1:
The patent changes the operating frequency to low frequency, which fundamentally alters the receiver coil design requirements. At low frequencies, the wavelength is much larger than the coil dimensions, allowing the use of smaller coils while maintaining adequate power reception. This parameter change enables miniaturization of the receiver device without sacrificing wireless power transfer capability.
Solution Approach 2:
The patent optimizes the spatial distribution and coupling geometry of the magnetic field at low frequencies, allowing efficient power transfer with compact coil configurations. By changing the operational regime to low frequency, the system exploits different electromagnetic field distribution patterns that enable smaller receiver coils to capture sufficient power.
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 approach enhances safety, efficiency, and applicability by reducing magnetic field exposure, enabling efficient power transfer over longer distances with smaller coils and lower frequencies, suitable for various applications including sensor arrays and medical devices.
Implementation Method 1
a current-carrying coil (transmitter) generates a low-frequency, time-varying magnetic field that induces a sinusoidal mechanical forcing function on a permanent magnet residing on a receiver
Implementation Method 2
The resulting magnet motion (e.g., vibration) can be converted into electrical power via electromechanical conversion
Data Source
AI summary
Wireless power transmission (WPT) systems are provided. For example, the WPT system can use one or more power transmitting coils and a receiver for electromagnetically coupled wireless power transfer. The electrodynamic receiver can be in the form of an electrodynamic transducer where a magnet is allowed to oscillate near a receiving coil to induce a voltage in the receiving coil, a piezoelectric transducer where the magnet causes a vibrating structure with a piezoelectric layer to move, an electrostatic transducer where movement of the magnet causes a capacitor plate to move, or a combination thereof. An alternating magnetic field from the transmitting coil(s) excites the magnet in the receiver into mechanical resonance. The vibrating magnet then functions similar to an energy harvester to induce voltage/current on an internal coil, piezoelectric material, or variable capacitor. Embodiments utilize magnetic coupling and electromechanical resonance for safe, spatially distributed, low-frequency power delivery to portable devices.