Hybrid Modulation Logic for Power Converter Overcurrent Protection

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Solution Overview

Problem

Existing power converter modulation methods either face issues with overcurrent leading to shutdowns, resonance, and noise due to their deterministic nature, or suffer from inefficiencies and increased thermal losses due to stochastic current control, making it challenging to achieve optimal performance across various criteria like cost, reliability, and electromagnetic compatibility.

Innovation Solution

A method that combines voltage-impressing and current-impressing modulation by using a control logic to logically link data from both modulation methods, allowing seamless switching between them based on operational conditions, thereby generating control signals that mitigate the disadvantages of each individual method.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If voltage-impressing modulation is used, then deterministic behavior and high control quality are achieved, but overcurrent events and resonance effects occur leading to shutdowns

Engineering Contradiction:
Improveoperational reliabilityVSAvoidovercurrent events and resonance
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent combines voltage-impressing modulation and current-impressing modulation into a hybrid control system. The control logic selectively applies voltage-impressing modulation during normal operation to maintain deterministic behavior, and switches to current-impressing modulation when overcurrent or resonance conditions are detected, thereby merging the advantages of both methods to eliminate shutdowns while maintaining reliability

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent implements dynamic switching between different modulation strategies based on real-time system conditions. The control logic continuously monitors operational parameters and adaptively changes the modulation mode, transitioning from static voltage-impressing control to dynamic hybrid control that responds to changing system states, thereby preventing overcurrent events and resonance while maintaining deterministic behavior

Inventive Principle:
Principle #15Dynamics

2Reliability

If current-impressing modulation is used, then overcurrent shutdowns are avoided, but thermal losses and switching frequency increase

Engineering Contradiction:
Improveoperational continuityVSAvoidthermal losses
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent applies current-impressing modulation only partially, specifically during conditions requiring overcurrent protection or resonance avoidance. During normal operation, voltage-impressing modulation is used for efficient deterministic control. This partial application of current-impressing modulation provides necessary operational continuity without incurring excessive thermal losses during routine operation

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The patent dynamically changes control parameters by switching between different modulation strategies. The control logic adjusts the modulation mode based on system conditions, changing from voltage-impressing (efficient but vulnerable to overcurrent) to current-impressing (protective but less efficient) modulation, thereby optimizing the balance between operational continuity and thermal loss minimization

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If voltage-impressing modulation is used, then defined switching frequency and control quality are achieved, but noise pollution and resonance effects require complex filters

Engineering Contradiction:
Improvecontrol qualityVSAvoidnoise pollution
Core Design Contradiction:
Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The patent converts the harmful noise and resonance effects generated by voltage-impressing modulation into beneficial operational insights. By monitoring these effects and using them as triggers to switch to current-impressing modulation, the system transforms noise-induced problems into useful feedback signals that initiate protective mode changes, thereby eliminating the need for complex filtering while maintaining control quality

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

Data Source

PatentEP2182626B1Method for operating a frequency converter and frequency converter operating by the method
Publication Date: 2018.11.28 SIEMENS AG
  • EP2182626B1 patent drawingFigure 1
  • EP2182626B1 patent drawingFigure 2
  • EP2182626B1 patent drawingFigure 3

AI summary

The method involves controlling semiconductor switches by a control logic (34) based on generated control signals (32), where the control logic obtains data for voltage-impressing modulation and data for current-impressing modulation. A logic UND-conjunction of the obtained data is carried out by the control logic for generation of the control signals. The data for voltage-impressing modulation are generated based on a voltage reference value (40) that is supplied to a signal generator (36). Independent claims are also included for the following: (1) a power converter device comprising a power converter (2) a computer program comprising instructions to perform a method for operating a power converter (3) a storage medium comprising instructions to perform a method for operating a power converter.