PCB-Based Power Component Temperature Sensing for Electrical Isolation

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Current hot drinks dispensing machines face challenges in effectively controlling the temperature of power components operating at mains voltage while maintaining reinforced electrical insulation, as existing solutions fail to provide reliable and non-bulky temperature monitoring due to distance constraints between high and low voltage components.

Innovation Solution

The electronic system places the temperature sensor on an opposite face of the electronic substrate from the power component, ensuring electrical isolation and allowing for closer proximity without violating insulation requirements, using a thermistor to monitor the triac's temperature and interrupting power supply when thresholds are exceeded.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the temperature sensor is placed close to the power component on the same side of the PCB, then temperature measurement precision is improved, but electrical insulation requirements are violated

Engineering Contradiction:
Improvetemperature measurement precisionVSAvoidelectrical insulation
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent moves the temperature sensor from the same plane as the power component to the opposite side of the PCB, utilizing the third dimension (depth/thickness of the board) to achieve both close thermal coupling for accurate measurement and sufficient electrical insulation distance. This spatial reconfiguration resolves the contradiction by adding a dimensional aspect to the arrangement.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The PCB itself acts as an intermediary element between the power component and the temperature sensor. By placing the sensor on the opposite side of the board, the PCB material serves as both a thermal conduction path (through vias and copper traces) and an electrical insulation barrier, enabling the sensor to be close to the power component while maintaining required insulation distances.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the power component and temperature sensor are placed on opposite faces of the electronic substrate, then electrical insulation is improved, but temperature measurement responsiveness deteriorates

Engineering Contradiction:
Improveelectrical insulationVSAvoidtemperature measurement responsiveness
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The patent employs thermal vias and copper traces within the PCB as intermediary thermal conduction paths. These intermediaries bridge the gap between the power component and the temperature sensor on the opposite face, enabling efficient heat transfer that maintains measurement responsiveness despite the physical separation required for electrical insulation.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The PCB structure with its layered construction and thermal vias acts as a flexible thermal conduction medium. The thin film-like thermal paths through the board thickness allow rapid heat transfer from the power component to the sensor, compensating for the increased distance and maintaining measurement speed.

Inventive Principle:
Principle #30Flexible shells and thin films

3Reliability

If the minimum distance of 5 millimeters is maintained between high voltage and low voltage components, then electrical safety is improved, but device compactness deteriorates

Engineering Contradiction:
Improveelectrical safetyVSAvoiddevice footprint
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The patent utilizes the vertical dimension (thickness of the PCB) to achieve the required 5mm electrical insulation distance without increasing the horizontal footprint. By placing components on opposite sides of the board and leveraging the board's thickness, the design maintains electrical safety while preserving device compactness in the planar dimensions.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 configuration enables reliable and responsive temperature measurement of the power component while ensuring electrical safety, reducing the assembly's footprint and meeting regulatory insulation standards, thus preventing overheating and potential malfunctions.

Implementation Method 1

The temperature sensor is a thermistor... quickly perceives said temperature variation

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

a thermistor to monitor the triac's temperature

Methodology Applied
Scientific EffectResistive temperature detection: Thermistor

Implementation Method 3

a heating element whose temperature is controlled... This is, for example, a resistor that partially dissipates the electrical energy supplied to it in the form of heat

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 4

ensuring electrical isolation and allowing for closer proximity without violating insulation requirements

Methodology Applied
Scientific EffectDielectric insulation: Dielectric

Data Source

PatentEP3809233B1Circuit for controlling a beverage dispensing machine with enhanced electrical safety
Publication Date: 2024.05.22 SEB SA
  • EP3809233B1 patent drawingFigure 1
  • EP3809233B1 patent drawingFigure 2~3

AI summary

The present invention relates to an electronic control system for a heating element for a hot beverage dispensing machine, comprising: - an electronic substrate (2) having a first face (2A) and a second face (2B), - at least one operative part of the electronic system having a power component (3) configured to control a power supply to the heating element, - at least one informational part of the electronic system having a temperature sensor (4) configured to generate a signal characteristic of an observed temperature of the power component (3), - means for processing the signal generated by the temperature sensor (4), configured to interrupt the power supply to the power component when said signal exceeds a predetermined threshold, the power component (3) being arranged on the first face (2A) and the temperature sensor being arranged on the second face (2B).