Synchronous Rectifier Control for Wireless Power Output Adjustment

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Solution Overview

Problem

Conventional wired charging methods for electronic devices are inconvenient and inefficient, necessitating the development of wireless power transfer systems that can efficiently and safely charge devices without physical conductors.

Innovation Solution

A wireless power transfer system utilizing synchronous rectifier control to adjust output power, where a transmitter and receiver are configured in a mutual resonant relationship, allowing for efficient energy transfer through a resonant circuit with a tuning circuit and rectifier circuit, enabling dynamic control of output power based on feedback and hysteresis adjustments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If wireless power transfer is implemented to eliminate cables and connectors, then convenience and ease of operation are improved, but energy transmission efficiency and power transfer reliability may deteriorate due to transmission losses

Engineering Contradiction:
Improvecharging convenienceVSAvoidtransmission loss
Core Design Contradiction:
Ease of operationVSLoss of energy

Solution Approach 1:

The patent applies resonant oscillation at specific frequencies (e.g., 6.78 MHz) to both transmitting and receiving coils, creating a strongly coupled resonant system that enables efficient wireless power transfer over distances much greater than the coil dimensions, thereby reducing transmission losses while maintaining charging convenience

Inventive Principle:
Principle #18Mechanical vibration

Solution Approach 2:

The system dynamically adjusts operating parameters including frequency, power level, and coil configuration to optimize power transfer efficiency under different conditions, adapting to maintain high efficiency while providing convenient wireless charging

Inventive Principle:
Principle #35Parameter changes

2Power

If output power is increased to meet growing device power requirements, then power delivery capability is improved, but safety and control precision may deteriorate

Engineering Contradiction:
Improveoutput powerVSAvoidsafety control
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The patent implements bidirectional communication and feedback mechanisms where the receiving device communicates power requirements to the transmitter, and the system continuously monitors power transfer conditions to adjust output dynamically, ensuring safe and reliable high-power delivery

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system transitions from static fixed-power design to dynamic adjustable power output, enabling real-time optimization of power delivery based on device needs, distance, and environmental conditions, thereby maintaining safety while meeting high power requirements

Inventive Principle:
Principle #15Dynamics

3Ease of operation

If transmission distance is increased to provide greater flexibility, then ease of operation is improved, but power transfer efficiency deteriorates due to increased losses

Engineering Contradiction:
Improvecharging flexibilityVSAvoidtransmission loss
Core Design Contradiction:
Ease of operationVSLoss of energy

Solution Approach 1:

By establishing resonant coupling between transmitting and receiving coils at matched frequencies, the system achieves efficient power transfer over distances much greater than the coil physical dimensions, enabling flexible positioning while maintaining acceptable efficiency

Inventive Principle:
Principle #18Mechanical vibration

Solution Approach 2:

The system dynamically adjusts operating frequency and power level based on detected distance and coupling conditions, optimizing efficiency at each transmission distance to maintain flexibility without excessive losses

Inventive Principle:
Principle #15Dynamics

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 efficient wireless power transfer over various distances, effectively charging devices by minimizing transmission losses and dynamically adjusting output power to optimize energy delivery, thus overcoming the limitations of wired charging.

Implementation Method 1

a power receiving element configured to receive wireless power via a magnetic field

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

A wireless power transfer system utilizing synchronous rectifier control to adjust output power, where a transmitter and receiver are configured in a mutual resonant relationship

Methodology Applied
Scientific EffectResonance: Resonance

Implementation Method 3

the rectifier circuitry configured to convert the induced alternating current (AC) signal to a direct current (DC) signal to charge the battery

Methodology Applied
Scientific EffectRectification:

Implementation Method 4

detune the receive circuit away from a resonant frequency to achieve a first output power level based on a voltage level of the battery

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentEP3326295B1Device, and method for adjusting output power using synchronous rectifier control
Publication Date: 2021.03.24 QUALCOMM INC
  • EP3326295B1 patent drawingFigure 1~3
  • EP3326295B1 patent drawingFigure 4
  • EP3326295B1 patent drawingFigure 5

AI summary

In one aspect, an apparatus for wireless receiving power comprises a receive circuit configured to receive wireless power via a magnetic field sufficient to power or charge a load. The apparatus further comprises a tuning circuit comprising a variable reactive element, coupled to the receive circuit, and configured to detune the receive circuit away from a resonant frequency to adjust an output power level to a first output power level. The apparatus comprises a rectifier, comprising a switch, coupled to the receive circuit and configured to rectify an alternating current to a direct current for supplying power to the load. The apparatus comprises a drive circuit configured to actuate the switch when a current through the switch satisfies a first non-zero current value and adjust the first non-zero current value to a second non-zero value to adjust the first output power level to a second output power level.