Wireless Power Receiver Rectifier Circuit Overvoltage Protection

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing wireless power transmission systems face inefficiencies due to impedance variations and overvoltage issues, which can lead to excessive current flow in protection circuits, increasing device size and cost when attempting to mitigate these problems.

Innovation Solution

A wireless power receiver with a rectifier circuit using bridge and double-voltage rectifier modes, combined with a protection circuit that includes switching elements controlled by a control circuit based on output voltage and inter-terminal voltage, to prevent excessive current flow and protect circuit elements from overvoltage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a protection circuit with switching elements is incorporated to protect against overvoltage, then circuit elements are protected from overvoltage, but excessive current may flow in the switching elements causing potential failure

Engineering Contradiction:

Improveprotection against overvoltageVSAvoidexcessive current flow

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A diode is introduced as an intermediary component between the switching element and the rectifier circuit. This diode acts as a mediator that prevents reverse current flow from the rectifier output to the switching element, thereby protecting the switching element from excessive current while maintaining the overvoltage protection function

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The diode is pre-configured in the circuit path to provide beforehand protection against excessive current. By placing the diode in series with the switching element before potential overvoltage events occur, the circuit is cushioned against harmful current flows that would otherwise damage the switching element

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Reliability

If elements capable of withstanding large current are used in the protection circuit, then excessive current can be withstood, but device size and cost increase

Engineering Contradiction:

Improvecurrent withstanding capabilityVSAvoiddevice size and cost

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The diode serves as a protective intermediary that enables the use of smaller, less expensive switching elements. By blocking reverse current flow, the diode allows standard switching elements to be used instead of requiring oversized, high-current-capability components, thereby reducing device size and cost

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

A simple, inexpensive diode is used as a sacrificial protective component that prevents damage to more expensive switching elements. The diode provides a cost-effective solution that protects the overall circuit without requiring expensive high-current-rated components

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

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 solution effectively suppresses excessive current flow in protection circuits while protecting both the protection circuit and device elements from overvoltage, enhancing system safety and efficiency without increasing device size or cost.

Implementation Method 1

a power reception unit (21) including a power reception coil (L2)

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a rectifier circuit (23) including a first diode (D1) whose anode is connected to one output end of the power reception unit (21), a second diode (D2) whose cathode is connected to the one output end, a third diode (D3) whose anode is connected to the other output end of the power reception unit (21), a fourth diode (D4) whose cathode is connected to the other output end

Methodology Applied

Scientific EffectDiode rectification: Diode

Implementation Method 3

when the value of an output voltage detected by a power receiving side voltage detection part exceeds a preset reference voltage value, the switching elements are activated to short the circuit to thereby protect the circuit elements from overvoltage

Methodology Applied

Scientific EffectCircuit shorting:

Data Source

PatentUS10903691B2Wireless power receiver and wireless power transmission system using the same

Publication Date: 2021.01.26 TDK CORP

AI summary

A wireless power receiver is provided with a power reception unit, a rectifier circuit including first to fourth diodes and first and second capacitors and converting AC power into DC, an anode of the first diode and a cathode of the second diode being connected to one output end of the power reception unit, an anode of the third diode and a cathode of the fourth diode being connected to the other output end thereof, and first and second capacitors being connected in parallel, respectively, to the third and fourth diodes, a protection circuit including a first switching element connected between the other output end of the power reception unit and an output end of the rectifier circuit, and a control circuit that controls the first switching element based on output voltage of the rectifier circuit and inter-terminal voltage of the first or second capacitor.