Frequency Converter Heating Control for High-Temperature Precision

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Solution Overview

Problem

Existing temperature control systems for heating elements in high-temperature applications, such as plastics pyrolysis plants, suffer from large temperature fluctuations and inefficiencies, leading to prolonged heating times and high power consumption.

Innovation Solution

Employing a frequency converter to control heating elements, allowing precise voltage regulation in 0.1-volt increments, thereby achieving accurate temperature control with minimal overshoot and reducing heating time by one-third to one-quarter.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional electrical control components (solid-state relays, PID controllers, thyristor controllers) are used to control heating elements, then the heating element can be switched on at relatively high voltage, but this leads to large temperature fluctuations, temperature overshoot, and unacceptably high temperature deviations particularly at high temperatures above 350°C

Engineering Contradiction:
Improvetemperature control precisionVSAvoidtemperature stability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent applies parameter changes by transitioning from conventional electrical control (solid-state relays, PID controllers, thyristor controllers) to a frequency converter for controlling the heating element. The frequency converter enables precise voltage regulation in 0.1-volt increments, fundamentally changing the control parameter resolution and eliminating the temperature overshoot and large fluctuations that occur with conventional high-voltage switching components.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The frequency converter provides dynamic voltage adjustment capability, allowing the control system to respond continuously to temperature changes rather than switching between fixed states. This dynamic control enables the system to maintain precise temperature control by adjusting voltage in small increments (0.1-volt steps) rather than making large, abrupt voltage changes that cause temperature overshoot.

Inventive Principle:
Principle #15Dynamics

2Productivity

If conventional electrical control components are set to relatively high voltage during heating phase, then the heating element switches on, but this causes temperatures to quickly exceed desired temperature and requires repeated adjustments over extended periods

Engineering Contradiction:
Improveheating speedVSAvoidtemperature adjustment time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The frequency converter enables preliminary action by allowing the system to apply precise, pre-calculated voltage levels from the start of heating. Instead of switching to high voltage and then making repeated adjustments, the system can immediately apply the appropriate voltage level (in 0.1-volt increments) to reach the target temperature in one step, eliminating the need for repeated up-and-down adjustments.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses feedback control where the frequency converter continuously monitors the actual temperature and adjusts the voltage to the heating element in real-time. This closed-loop control prevents temperature overshoot by reducing voltage when the target temperature is approached, eliminating the need for repeated manual or automated adjustments that waste time.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If conventional control components are used with repeated temperature adjustments, then temperature control is eventually achieved, but this results in unnecessarily high power consumption

Engineering Contradiction:
Improvetemperature accuracyVSAvoidpower consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The frequency converter enables continuous useful action by maintaining steady, precise voltage control at the heating element. Instead of the stop-start nature of conventional control with repeated adjustments, the system continuously applies the exact voltage needed to maintain the target temperature, eliminating the energy waste associated with repeated heating cycles and temperature overshoot corrections.

Inventive Principle:
Principle #20Continuity of useful action

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

Achieves precise temperature control with +/- 0.1°C accuracy, resulting in at least 50% energy savings and early detection of heating element failures.

Implementation Method 1

a frequency converter or consists of one (13) for controlling the at least one heating element (11)

Methodology Applied
Scientific EffectFrequency conversion:

Implementation Method 2

Heating elements essentially represent an ohmic resistance, whereby heat is generated by means of an electric current flowing through them

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP4671345A1Heating elements driven by a frequency converter for heating a substance or substance mixture in a device
Publication Date: 2025.12.31 ENESPA TECHNOLOGIES AG
  • EP4671345A1 patent drawingFigure 1~2
  • EP4671345A1 patent drawingFigure 3
  • EP4671345A1 patent drawing

AI summary

In order to improve a device for heating a substance or mixture of substances, wherein the device has a heater with at least one heating element and at least one control device for controlling the at least one heating element, in such a way that the temperature can be set as precisely as possible even in high temperature ranges, it is proposed that the at least one control device has or consists of a frequency converter.