PWM Control for Electric Heating Power Distribution

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Solution Overview

Problem

Current electric heating systems in vehicles face inefficiencies due to all-or-nothing control methods, leading to instability in electrical consumption networks, reduced heating quality, and increased costs, weight, and bulk from using more powerful energy producers.

Innovation Solution

A method and device for controlling electric power supply to multiple heating means by generating interrupt commands based on available power and priority, allowing for pulse-width modulation to optimize power distribution between heating means and the electrical consumption network.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If all-or-nothing control mode is used for electric heating means, then device complexity is reduced, but electrical network stability deteriorates and heating quality is reduced

Engineering Contradiction:
Improvecontrol system complexityVSAvoidelectrical network stability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent applies dynamics by transitioning from static all-or-nothing switch control to dynamic PWM (pulse width modulation) control. The control unit dynamically adjusts the duty cycle of interrupt commands sent to switching devices, enabling continuous modulation of heating power between 0% and 100%. This dynamic control allows the system to adapt to varying power availability and heating requirements, maintaining electrical network stability while providing precise heating control.

Inventive Principle:
Principle #15Dynamics

2Power

If more powerful electrical energy producers are used, then power supply capacity is improved, but cost, weight, and bulk increase

Engineering Contradiction:
Improvepower supply capacityVSAvoidsystem weight
Core Design Contradiction:
PowerVSWeight of moving object

Solution Approach 1:

The patent applies parameter changes by utilizing PWM modulation to vary the effective power delivery parameter. Instead of requiring a larger power producer to meet peak heating demands, the system maintains a smaller power producer and uses parameter modulation (duty cycle adjustment) to deliver the required average power. This allows the electrical energy producer to be sized for the minimum required power while still meeting heating demands through temporal modulation, thereby reducing weight, cost, and bulk.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If all-or-nothing control is used, then ease of operation is improved, but heating quality and power utilization deteriorate

Engineering Contradiction:
Improvecontrol simplicityVSAvoidheating efficiency
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The patent applies periodic action through PWM control, where interrupt commands are sent at regular intervals to switching devices. The control unit generates a series of periodic pulses with varying duty cycles, creating a rhythmical on-off pattern that averages to the desired power level. This periodic modulation maintains heating efficiency by delivering power in optimized bursts rather than continuous fixed increments, while the automated nature of the periodic control preserves ease of operation.

Inventive Principle:
Principle #19Periodic action

4Power

If maximum electrical power is supplied to heating means, then heating power is improved, but electrical network stability deteriorates due to flapping

Engineering Contradiction:
Improveheating powerVSAvoidelectrical network stability
Core Design Contradiction:
PowerVSStability of the object's composition

Solution Approach 1:

The patent applies feedback by having the control unit continuously monitor the available electrical power from the producer and the state of the electrical network. Based on this feedback information, the control unit dynamically adjusts the duty cycle of interrupt commands to switching devices, modulating heating power to match available capacity. This closed-loop feedback control prevents flapping by ensuring heating power demand never exceeds supply capacity, maintaining both heating effectiveness and electrical network stability.

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 maximizes electrical power supply while maintaining it below the maximum producer capacity, optimizing heating power and reducing the need for more powerful energy producers, thus improving heating quality and reducing costs and system weight.

Implementation Method 1

at least two electrical heating means, such as for example heating resistors

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP3750377B1Method for controlling the power supply of electric heating means of a system, as a function of the available electric power and needs
Publication Date: 2022.08.03 PSA AUTOMOBILES SA
  • EP3750377B1 patent drawingFigure 1~2
  • EP3750377B1 patent drawingFigure 3~4
  • EP3750377B1 patent drawingFigure 5

AI summary

The invention relates to a method (10-40) which controls the electric power supply of a system, comprising an electric energy producer coupled with an electricity consumption grid and with electric heating means of power components, and comprising a step of generating, for interrupting means installed between the electric energy generator and the heating means and which can each be placed according to a command in a first off-state and a second on-state, commands as a function of first and second values defining electric power needs for the grid and the heating means, and a maximum electric power that can be supplied. A command imposing the first state is generated for the heating means, having minimum priority among the priorities attributed to the heating means needing to be used, when the sum of the first and second values is strictly higher than the maximum electric power.