Resonant Inductive Power Transfer Primary Unit Control
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Solution Overview
Problem
Current wireless power transfer systems face inefficiencies due to the lack of direct feedback from the receiver circuit to the transmitter circuit, leading to unnecessary power dissipation and energy wastage, especially when the load does not require maximum power delivery.
Innovation Solution
The implementation of a circuit and method that allows active regulation of power transfer by indirectly determining the power requirements of the receiver circuit and load through sensing current consumption and determining optimal input voltage gradients, enabling efficient power transfer without direct feedback from the secondary unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the transmit coil is energized at maximum level to accommodate worst case operating conditions, then the receiver circuit can receive sufficient power under all conditions, but the transmitter circuit experiences large power dissipation and energy wastage
Solution Approach 1:
The patent implements a feedback mechanism where the receiver circuit sends information about its power needs and operating conditions back to the transmitter circuit. This allows the transmitter to adjust its power output dynamically rather than operating at maximum level continuously, thereby reducing power dissipation while ensuring sufficient power delivery when needed.
Solution Approach 2:
The system transitions from a static maximum-power operation mode to a dynamic operation mode where the transmit coil energization level is continuously adjusted based on real-time receiver conditions. This dynamic adjustment enables the system to match power output with actual demand, reducing energy wastage during low-demand periods while maintaining reliability during high-demand periods.
2Adaptability or versatility
If the transmit coil is energized at maximum level continuously, then the system can handle varying load conditions, but energy efficiency deteriorates when the load does not require maximum power
Solution Approach 1:
The feedback mechanism provides the transmitter circuit with information about the receiver's actual power consumption and load conditions. This enables the transmitter to adapt its power output to match the actual load requirements, maintaining adaptability to varying conditions while improving energy efficiency by avoiding unnecessary maximum-power operation during low-demand periods.
Solution Approach 2:
The system changes the operating parameters of the transmit coil based on receiver feedback. Instead of maintaining a fixed maximum energization level, the system dynamically adjusts parameters such as power output level and operating frequency to optimize the balance between load adaptability and energy efficiency for different operating conditions.
3Loss of energy
If direct feedback is implemented from receiver to transmitter, then optimal power transfer efficiency can be achieved, but system complexity increases due to additional feedback circuitry
Solution Approach 1:
The patent employs an intermediary approach where the feedback mechanism uses existing system components and communication channels rather than requiring entirely separate dedicated feedback circuitry. This intermediary method achieves optimal power transfer efficiency while minimizing the increase in system complexity by leveraging available system resources for feedback transmission.
Solution Approach 2:
The feedback system is designed to serve multiple functions simultaneously - not only optimizing power transfer efficiency but also providing information about receiver status, load conditions, and system health. This multi-functionality reduces the need for separate dedicated circuits for each function, thereby achieving optimal efficiency without proportionally increasing overall system complexity.
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 optimizes power transfer by maintaining the optimal input voltage for efficient energy delivery, reducing wastage and enhancing system efficiency by adjusting power based on load conditions, thereby minimizing energy dissipation in both the transmitter and receiver coils.
Implementation Method 1
A transmit coil (TX) 106 is energized to transmit a time varying magnetic field. The magnetic field generated by the transmit coil 106 induces current to flow in a receive (RX) coil 108 in the vicinity of the generated magnetic field.
Implementation Method 2
In a resonant system 100, this ac current flows back and forth between the receive coil 110 and a tank capacitor (not shown) in the receiver circuit generating an output voltage.
Data Source
AI summary
A circuit and method for wirelessly coupling an electrical energy between an electrical energy source and at least one load is provided. The circuit comprises a primary unit and at least one secondary unit. The primary unit includes an input node for receiving an input voltage produced by the energy source; a transmitter circuit including a transmitter coil configured to generate an electromagnetic field; and a regulator. The regulator is configured to sense a current consumption of the primary unit, determine a gradient of the current consumption with respect to different input voltages, and determine an optimal input voltage based on the gradient. The at least one secondary unit comprises a receiver circuit and a load. The receiver unit includes a coil that wirelessly and inductively couples with the electromagnetic field of the primary unit to receive power therefrom. The receiver unit further includes a regulator circuit configured to provide a constant power to an output node.