Inductive Power Transmission Amplifier Zero Voltage Switching

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Solution Overview

Problem

Existing inductive power transmission systems face challenges in achieving efficient and low-interference power supply, especially at high frequencies, to cater to diverse electrical consumers with different current consumption classes, as conventional amplifiers struggle to minimize power losses and interference while operating in zero-voltage and zero-current switching modes.

Innovation Solution

A method utilizing a class D amplifier reconfigured as a class DE amplifier, operating in zero-voltage and zero-current switching modes, with a sequence control generating square-wave signals to optimize switching of electronic switches, and a control loop for adjusting pulse widths to ensure efficient power transmission, employing a complex programmable logic device or ASIC for sequence control, and a microcontroller for optimal power regulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If conventional amplifiers are used for inductive power transmission, then power can be transmitted to electrical devices, but power losses and interference increase at high frequencies

Engineering Contradiction:
Improvepower lossesVSAvoidstable operation at high frequencies
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The amplifier dynamically adapts its switching mode between ZVS and ZCS based on operating conditions, allowing optimal performance across different frequencies and power levels. This dynamic adaptation minimizes power losses while maintaining stable operation at high frequencies by selecting the appropriate switching mode for each operational state.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the switching parameters of the amplifier by implementing zero-voltage switching and zero-current switching modes. This parameter change fundamentally alters the switching behavior to occur at optimal points in the AC cycle, thereby minimizing power losses and interference at high frequencies while maintaining reliable power transmission.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If amplifiers operate at high frequencies for efficient power transmission, then power transmission efficiency improves, but interference and power losses increase

Engineering Contradiction:
Improvepower transmission efficiencyVSAvoidinterference
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The invention converts the potentially harmful effects of high-frequency operation into benefits by implementing ZVS and ZCS modes. The zero-crossing switching points transform what would normally be sources of interference and power loss into efficient power transmission opportunities, allowing high-frequency operation to benefit productivity while minimizing harmful effects.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Loss of energy

If zero-voltage and zero-current switching modes are implemented, then power losses and interference are minimized, but amplifier design and control complexity increase

Engineering Contradiction:
Improvepower lossesVSAvoidamplifier design complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The amplifier design integrates multiple functions into a unified control system that handles both ZVS and ZCS modes, power level adjustment, and interference mitigation through a single control architecture. This multi-functionality reduces the need for separate control circuits for each function, thereby managing complexity while achieving minimal power losses and interference.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Object-generated harmful factors

If zero-voltage and zero-current switching modes are implemented, then interference is reduced, but control and switching precision requirements increase

Engineering Contradiction:
ImproveinterferenceVSAvoidswitching precision
Core Design Contradiction:
Object-generated harmful factorsVSManufacturing precision

Solution Approach 1:

The control system incorporates feedback mechanisms that monitor voltage and current waveforms in real-time, automatically detecting zero-crossing points and adjusting switching timing accordingly. This feedback control ensures precise switching at the optimal moments to minimize interference, while the system adapts to variations in operating conditions without requiring manual calibration.

Inventive Principle:
Principle #23Feedback

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 minimizes power losses and interference, ensuring stable and efficient inductive power transmission across various devices by precisely controlling electronic switches in zero-voltage and zero-current switching modes, even at high frequencies, thereby supporting devices with different power classes.

Implementation Method 1

inductive power transmission by means of at least one transmission coil to which electrical power is applied by an amplifier

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

series resonant circuit and two capacitances assigned to the electronic switches

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentEP3266115B1Method for the inductive transmission of current
Publication Date: 2020.10.14 WITECH
  • EP3266115B1 patent drawingFigure 1~5
  • EP3266115B1 patent drawingFigure 2~4
  • EP3266115B1 patent drawingFigure 6

AI summary

The invention relates to a method for the inductive transmission of current by means of at least one emission coil supplied with electric power by an amplifier. According the invention, the amplifier is operated in a Zero Voltage Switching (ZVC) mode and in a Zero Current Switching (ZCV) mode.