Multi-Inverter Assembly for Heat Pump Harmonic Reduction

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Solution Overview

Problem

Heat pumps generate harmonics through frequency- or speed-controlled electric motors, which degrade power grid quality, and their increasing electricity consumption poses a stability risk, necessitating improved control systems without reducing efficiency.

Innovation Solution

An electrical assembly with a single intermediate circuit and multiple power modules controls electric motors, reducing harmonics and simplifying design by eliminating the need for individual converters, while maintaining high efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If frequency- or speed-controlled electric motors are used to maintain high efficiency, then the heat pump can operate close to optimal operating points, but harmonics are generated that degrade power grid quality

Engineering Contradiction:
Improveheat pump efficiencyVSAvoidharmonics
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

Multiple power modules are merged into a single inverter system with one rectifier and one intermediate circuit. This consolidation maintains the ability to control multiple motors at optimal operating points while reducing harmonic generation by eliminating multiple separate rectifiers that would each introduce harmonics into the power grid.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

A single inverter system performs multiple functions by controlling several power modules that drive different motors. The unified rectifier and intermediate circuit serve all power modules, providing universal power conversion while maintaining individual motor control capabilities for high efficiency operation.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Productivity

If multiple independent converters are used to control each electric motor, then each motor can be controlled optimally, but the device complexity increases

Engineering Contradiction:
Improvemotor control efficiencyVSAvoidinverter structure
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

Multiple independent converters are merged into a single inverter system where one rectifier and one intermediate circuit serve multiple power modules. Each power module maintains independent control capability for its motor, but the shared components reduce overall system complexity and component count.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single inverter system is designed with multi-functionality to control multiple motors through separate power modules. The unified structure provides universal power conversion functions while maintaining the ability to independently control each motor's operating parameters for optimal efficiency.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 enhances grid stability and reduces harmonic interference by controlling multiple motors with a single rectifier, maintaining efficiency and simplifying the heat pump design.

Implementation Method 1

the rectifier (110) can be connected to a power grid (102) that provides alternating voltage, for rectifying the electrical alternating voltage and for providing the rectified voltage to the intermediate circuit (120)

Methodology Applied
Scientific EffectRectification: Diode

Data Source

PatentEP4604386A1Multi-inverter for a heat pump
Publication Date: 2025.08.20 STIEBEL ELTRON GMBH & CO KG
  • EP4604386A1 patent drawingFigure 1
  • EP4604386A1 patent drawingFigure 2
  • EP4604386A1 patent drawing

AI summary

The invention relates to an electrical assembly (100) for controlling at least two electric motors (M1, M2,... Mn) of a heat pump (300) and an associated heat pump (300). The assembly comprises at least two power modules (130), an intermediate circuit (120), and a rectifier (110). The rectifier (110) is connectable to a power grid that provides alternating voltage, for rectifying the alternating voltage and for providing the rectified voltage to the intermediate circuit (120). The intermediate circuit (120) is designed to supply each power module (130) of the at least two power modules (130) with electrical current. Each power module (130) is configured to provide an alternating electrical current with a controllable frequency and/or amplitude for the power-variable control of one electric motor (M1, M2,... Mn) of the heat pump (300).