Grid-Forming Power Conversion Frequency Control Without DC Current Loop

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Solution Overview

Problem

Existing grid-forming power conversion control devices struggle to control frequency at high speeds without controlling DC current, which complicates the configuration and slows down control speed.

Innovation Solution

A grid-forming power conversion control device comprising a power conversion unit and a frequency control unit that calculates the output frequency without controlling the DC current, allowing for fast and simple frequency control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If DC current control is implemented in grid-forming power conversion control, then frequency control capability is improved, but device complexity increases and control speed decreases

Engineering Contradiction:

Improvefrequency control capabilityVSAvoidcontroller configuration

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts and removes the DC current control function from the control system. Instead of controlling DC current to achieve frequency control, the system directly measures output frequency and controls the power conversion unit based on frequency deviation, eliminating the need for complex DC current controllers while maintaining frequency control capability

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the traditional electrical control mechanism (DC current control) with a direct frequency measurement and control mechanism. By using frequency detection and direct power adjustment, the system substitutes a simpler control approach for the more complex DC current control system

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Stability of the object's composition

If DC current control is implemented in grid-forming power conversion control, then frequency stability is improved, but control speed decreases

Engineering Contradiction:

Improvefrequency stabilityVSAvoidcontrol speed

Core Design Contradiction:

Stability of the object's compositionVSSpeed

Solution Approach 1:

The patent implements continuous frequency measurement and continuous power adjustment without the intermediate step of DC current control. The controller continuously monitors output frequency and adjusts the power conversion unit in real-time, maintaining both stability and fast response speed through uninterrupted direct control

Inventive Principle:

Principle #20Continuity of useful action

Solution Approach 2:

The system uses direct frequency feedback from the output stage to control the power conversion unit. By measuring output frequency directly and feeding this information back to adjust power conversion, the system achieves both frequency stability and rapid response without the delays introduced by DC current control loops

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS20250175004A1Grid-forming power conversion control device and method

Publication Date: 2025.05.29 KOREA GRID FORMING CO LTD

AI summary

The present technology relates to a grid-forming power conversion control technology and, more specifically, to a grid-forming power conversion control device and a grid-forming power conversion control method. According to an embodiment, the output frequency of a grid-forming power conversion device can be controlled without a complicated current controller, which enables a simple structure and a high control speed.