Voltage Angle Control for Grid Front End Converters

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Solution Overview

Problem

Direct-axis- and quadrant-axis-based control of Fundamental Front End (FFE) converters require complex firing angle calculations and special waveform generators, leading to poor regulation performance.

Innovation Solution

The system employs flux angle control by generating an output voltage angle with an angular canceling function that cancels the angular control portion of the dynamic response of the grid, allowing the control signal to control the grid as a second-order quadrant-axis current, simplifying the control process and improving regulation performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If direct-axis- and quadrant-axis-based control with firing angle calculations is used, then the converter can be controlled, but the control complexity increases and regulation performance deteriorates

Engineering Contradiction:

Improvecontrol simplicityVSAvoidregulation performance

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent transforms the control parameters from firing angle calculations to voltage angle control. By changing the controlled parameter from complex angular calculations to direct voltage angle regulation, the system achieves both simplified control and improved regulation performance. The voltage angle control method directly regulates the output voltage angle without requiring complex firing angle computations, thereby resolving the contradiction between control simplicity and regulation performance.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If complex firing angle calculations are performed, then the converter control is achieved, but the computational complexity and device requirements increase

Engineering Contradiction:

Improvecontrol efficiencyVSAvoidwaveform generator complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the complex waveform generation function from the control system. By using voltage angle control instead of traditional firing angle control with specialized waveform generators, the system removes the need for complex computational blocks and special-purpose hardware, thereby improving control efficiency while reducing device complexity.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical/computational system of firing angle calculations with an electrical control system based on voltage angle regulation. This substitution eliminates the need for complex mathematical computations and specialized waveform generation hardware, achieving simpler and more efficient control through direct voltage angle manipulation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS10122175B1Voltage angle control of a fundamental front end converter for a grid

Publication Date: 2018.11.06 ROCKWELL AUTOMATION TECH INC

AI summary

For voltage angle control, a control module generates a control signal for a grid. A canceling function generates an output voltage angle as a function of the control signal that regulates the grid. The output voltage signal includes an angular canceling function that cancels an angular control portion of a dynamic response of the grid such that the control signal controls the grid as a second-order quadrant-axis current.