Contactless Power Receiving Device Smoothing Circuit

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Solution Overview

Problem

Contactless power transfer and receiving devices using inductive coupling face efficiency reduction due to inefficiencies in constituent parts like power transfer amplifiers, rectifier circuits, and DC-DC converters, leading to unstable operation and noise issues, particularly with impedance matching and voltage convergence problems.

Innovation Solution

Incorporating a power receiving coil, a rectifier circuit with smoothing capabilities, and a switching power supply, along with a smoothing circuit that includes inductors and capacitance elements to manage high-frequency signals and impedance, thereby stabilizing operation and reducing noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple power conversion stages are used (power transfer amplifier, rectifier circuit, DC-DC converter), then power can be efficiently transferred and converted, but device stability becomes unstable due to impedance matching and voltage convergence problems

Engineering Contradiction:

Improvepower conversion efficiencyVSAvoiddevice operation stability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies preliminary action by pre-configuring the impedance matching network and voltage regulation parameters before power transfer begins, and by establishing stable operating points for each conversion stage in advance, thereby preventing voltage convergence problems and ensuring stable operation throughout the power conversion process

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent uses feedback control to continuously monitor voltage and current parameters across all power conversion stages, and to dynamically adjust operating conditions to maintain stability and prevent divergence, ensuring reliable operation even under varying load conditions

Inventive Principle:

Principle #23Feedback

2Power

If high-frequency signals are processed in rectifier circuit and power transfer amplifier, then power transfer function is achieved, but noise is generated affecting device performance

Engineering Contradiction:

Improvepower transfer capabilityVSAvoidnoise generation

Core Design Contradiction:

PowerVSObject-generated harmful factors

Solution Approach 1:

The patent extracts and removes high-frequency noise components from the power conversion process by using filtering circuits that separate the useful power transfer signals from unwanted noise byproducts, and by isolating noise-generating stages from sensitive components through shielding and grounding techniques

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent converts the harmful high-frequency noise into beneficial effects by using the switching actions in the power transfer amplifier and rectifier circuit to generate controlled high-frequency signals that are then resonantly coupled through the coils, while damping circuits suppress unwanted noise frequencies and convert them into heat that is dissipated by thermal management systems

Inventive Principle:

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

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 solution enhances the stability and efficiency of contactless power transfer and receiving devices by improving impedance matching and reducing noise, ensuring stable operation and efficient power conversion.

Implementation Method 1

a power receiving coil configured to receive power from a contactless power transfer device

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a rectifier circuit configured to rectify the power received by the power receiving coil to form a rectified output

Methodology Applied

Scientific EffectRectification: Diode

Implementation Method 3

a smoothing circuit configured to smooth the rectified output on the high potential side and the rectified output on the low potential side, thereby forming a DC voltage; the smoothing circuit includes a first inductor configured to transmit the rectified output on the high potential side, a second inductor configured to transmit the rectified output on the low potential side

Methodology Applied

Scientific EffectElectrical smoothing: Capacitance

Implementation Method 4

a switching power supply configured to convert the DC voltage from the smoothing circuit to a first voltage

Methodology Applied

Scientific EffectSwitching conversion:

Data Source

PatentUS10971953B2Contactless power receiving device, contactless power transfer device, and contactless power transfer and receiving device

Publication Date: 2021.04.06 MAXELL LTD

AI summary

A contactless power receiving device includes a power receiving coil receiving power from a contactless power transfer device, a rectifier circuit rectifying the power to form a rectified output on a high potential side and a rectified output on a low potential side, a smoothing circuit receiving the rectified output on the high potential side and the rectified output on the low potential side, and a switching power supply converting a DC voltage from the smoothing circuit to a first voltage. The smoothing circuit includes a first inductor transmitting the rectified output on the high potential side, a second inductor transmitting the rectified output on the low potential side, and a smoothing capacitance element to which the rectified output on the high potential side and the rectified output on the low potential side are supplied, and the rectified output on the low potential side is connected to a ground potential.