3-Level Power Converter Feedback Correction for Residual Error

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Solution Overview

Problem

Traditional 3-level power converter architectures isolate feedback control loops, preventing the utilization of information from one loop to correct residual errors in the other, leading to inefficiencies and increased group delay.

Innovation Solution

A closed-loop feedback control system with orthogonal feedback control loops for regulating duty cycle and balance factor, incorporating a correction block that applies a correction term based on parameters from the other loop to minimize group delay and enhance bandwidth.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If feedback control loops are isolated from one another, then each loop can be independently controlled, but residual errors in one loop cannot be corrected using information from the other loop

Engineering Contradiction:

Improvecontrol precisionVSAvoidinformation utilization

Core Design Contradiction:

Measurement precisionVSLoss of information

Solution Approach 1:

The patent merges the two isolated feedback control loops by introducing a correction block that combines information from both loops. The first feedback control loop regulates duty cycle while the second regulates balance factor, and the correction block uses the balance factor information to correct residual errors in the duty cycle loop, thereby utilizing information that would otherwise be lost in isolated loops

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent implements a feedback mechanism where the correction block takes the balance factor parameter from the second loop and feeds it back as a correction term to the first loop. This feedback allows the system to use information from one control loop to improve the precision of another loop, reducing residual errors that would persist in isolated loops

Inventive Principle:

Principle #23Feedback

2Reliability

If traditional filtering is used in feedback loops, then noise is reduced, but group delay increases and bandwidth is reduced

Engineering Contradiction:

Improvenoise filteringVSAvoidgroup delay

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The correction block applies preliminary correction to the duty cycle control using balance factor information before the signal goes through the filtering stage. By correcting residual errors in advance using information from the orthogonal loop, the system reduces the need for extensive filtering, thereby reducing group delay while maintaining noise rejection

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent changes the parameter being used for correction from traditional filtering approaches to using the balance factor parameter from the second feedback loop. This parameter change allows the system to achieve error correction through information fusion rather than through time-consuming filtering operations, reducing group delay while maintaining reliability

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS20240372455A1Residual error correction in a 3-level power converter feedback loop

Publication Date: 2024.11.07 CIRRUS LOGIC INT SEMICON LTD

AI summary

A closed-loop feedback control system may include a first feedback control loop configured to regulate a first physical quantity, a second feedback control loop orthogonal to the first feedback control loop and configured to regulate a second physical quantity, and a correction block configured to apply a correction term to the first feedback control loop based on a parameter of the second feedback control loop.