Converter Submodule Charging Phases for Fast Start-Up Transition

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Solution Overview

Problem

Existing converters face challenges in transitioning to normal operating mode quickly after an initial start-up when submodule energy stores are not sufficiently charged, leading to asymmetrical charging ratios and inefficiencies.

Innovation Solution

A converter design with submodule control devices that initiate a charging operating mode with phases, allowing communication-ready submodules to set voltage presets, enabling targeted charging of some submodules while others are excluded, minimizing asymmetries and ensuring all submodules reach optimal charge levels for seamless transition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If all submodules are charged simultaneously in a conventional manner after initial start-up, then the charging process is simple to control, but the transition to normal operating mode is slow and asymmetries between module devices occur

Engineering Contradiction:

Improvetransition speed to normal operating modeVSAvoidcharging control complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The charging process is segmented into multiple charging phases (first charging phase, second charging phase, third charging phase) instead of uniform simultaneous charging. This allows different submodules to progress through charging stages at different rates, enabling faster overall transition while maintaining controllable complexity through phase-based management.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The charging control dynamically adjusts which submodules are charged and at what rate based on real-time conditions. Module control devices determine whether to charge submodules in the first or second charging phase based on voltage thresholds and communication readiness, creating a dynamic rather than static charging strategy that speeds up transition.

Inventive Principle:

Principle #15Dynamics

2Reliability

If submodule energy stores are charged uniformly, then charging control is straightforward, but asymmetries between module devices develop leading to inefficiencies

Engineering Contradiction:

Improvesymmetry of charging ratiosVSAvoidcharging coordination complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Different submodules receive different charging treatments based on their individual states. Some submodules are charged in the first charging phase while others are charged in the second charging phase, creating local quality differences in the charging process that prevent asymmetries and ensure all submodules reach optimal charge levels appropriately.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The system uses feedback from submodule communication status and voltage levels to adjust charging assignments. Module control devices monitor whether submodules are communications-ready and adjust which charging phase to apply, creating a feedback-based control mechanism that maintains symmetry without requiring complex centralized coordination.

Inventive Principle:

Principle #23Feedback

3Productivity

If some submodules are excluded from charging to create asymmetry, then targeted charging optimization is achieved, but control complexity increases

Engineering Contradiction:

Improvecharging efficiencyVSAvoidcharging control simplicity

Core Design Contradiction:

ProductivityVSEase of operation

Solution Approach 1:

The system performs preliminary actions by assigning submodules to different charging phases based on initial conditions before full charging begins. This preliminary segmentation allows targeted charging optimization to be achieved through pre-planned phase assignments rather than complex real-time control, maintaining ease of operation.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Not all submodules are charged in all phases - some submodules are selectively excluded from certain charging phases based on their communication readiness and voltage levels. This partial action approach optimizes charging efficiency by applying charging only where needed and when ready, simplifying control through clear inclusion/exclusion criteria.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS12476558B2Converter having a quick transition to a normal operating mode after an initial start-up

Publication Date: 2025.11.18 SIEMENS ENERGY GLOBAL GMBH & CO KG

AI summary

A converter has module devices each with a series connection of at least two partial modules being electrically connected in series. A central device is configured to switch module control devices, in which a sum of the transmitted voltage values or the transmitted sum value reaches a predefined voltage threshold, into a second charging phase of a charging operation by transmitting a first voltage specification relating to switched-off partial modules and a second voltage specification relating to switched-on partial modules to the module control devices. The module devices are configured to meet the first and second voltage specifications by setting none, one or more of the communication-capable partial modules thereof into a switched-on operating state and none, one or more of the other communication-capable partial modules thereof into a switched-off operating state, and to continue the charging of the energy stores which are in the switched-on and blocked operating state.