Pulse-Controlled Inverter Switching Reduction

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Solution Overview

Problem

Power converters, particularly those used in electrical drives, face high energy requirements due to frequent switching operations of semiconductor switches like IGBTs, leading to increased power consumption and heat generation, which affects their reliability and lifespan.

Innovation Solution

Implementing a pulse-controlled inverter system that suppresses control signals to semiconductor switches when current flows through freewheeling diodes, reducing the number of switching operations and thus minimizing power consumption and heat generation by only activating switches when necessary.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If semiconductor switches are frequently switched to control AC voltage output, then the power converter can provide precise voltage control for electrical machines, but the power consumption and heat generation increase significantly

Engineering Contradiction:
Improvevoltage control precisionVSAvoidpower consumption
Core Design Contradiction:
Ease of operationVSUse of energy by moving object

Solution Approach 1:

The patent extracts the unnecessary switching operations from the control process. By detecting when current flows through freewheeling diodes, the system identifies and removes redundant switch actuations, keeping only the essential switching operations needed for voltage control.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The freewheeling diodes naturally conduct current during certain phases of operation, providing self-service functionality that eliminates the need for active semiconductor switch control during these periods. The system leverages this natural current path to reduce switching frequency.

Inventive Principle:
Principle #25Self-service

2Adaptability or versatility

If semiconductor switches are frequently switched to maintain output voltage, then the power converter can adapt to varying load conditions, but heat generation increases affecting reliability

Engineering Contradiction:
Improveload adaptationVSAvoidheat generation
Core Design Contradiction:
Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The patent removes unnecessary switching operations that generate heat while preserving the essential switching needed for load adaptation. Current detection through freewheeling diodes identifies which switching operations can be eliminated without compromising load following capability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent converts the natural current conduction through freewheeling diodes, which was previously seen as a limitation, into a beneficial feature for reducing switching frequency and heat generation while maintaining load adaptability.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Ease of operation

If control signals are continuously sent to semiconductor switches, then precise voltage control is maintained, but the actuation processes consume excessive power

Engineering Contradiction:
Improvevoltage controlVSAvoidactuation power loss
Core Design Contradiction:
Ease of operationVSLoss of energy

Solution Approach 1:

The patent extracts and eliminates redundant control signals that would be continuously sent to semiconductor switches. By monitoring freewheeling diode current, the system identifies and removes unnecessary actuation commands, transmitting control signals only when essential for voltage control.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of continuous control signal transmission, the system uses periodic current detection through freewheeling diodes to determine when switching is necessary, creating an intermittent control pattern that reduces actuation power loss while maintaining voltage control.

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP3219005B1Power converter and method for operating a power converter
Publication Date: 2019.12.18 ROBERT BOSCH GMBH
  • EP3219005B1 patent drawingFigure 1
  • EP3219005B1 patent drawingFigure 2
  • EP3219005B1 patent drawingFigure 3

AI summary

The invention relates to a pulse-controlled inverter comprising one or more semiconductor switches and freewheeling diodes arranged in parallel to each semiconductor switch. The semiconductor switches are triggered only when the current does not flow through a freewheeling diode that is arranged in parallel to the semiconductor switch. This allows the number of triggering processes for the semiconductor switch to be reduced. The reduced number of triggering processes for the semiconductor switches results in lower power losses and an increased service life of the entire system.