Dual H-Bridge Converter Control for PFC and Harmonic Reduction
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Solution Overview
Problem
Existing switched-mode converter control methods are complex and do not effectively ensure power factor correction (PFC) with efficient power transfer between H bridges coupled by a transformer.
Innovation Solution
A method of controlling a converter with two H bridges coupled by a transformer, where switching sequences are generated based on a common frequency and calculated to achieve a desired power transfer equality, with phase shifts and duty cycles optimized for PFC operation, ensuring efficient energy flow and reduced harmonics in the AC current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If traditional switched-mode converter control methods are used, then the converter can transfer power between H bridges, but the control complexity increases and power factor correction performance deteriorates
Solution Approach 1:
The patent transforms the complex multi-parameter control problem into a simplified single-parameter control scheme by changing the control approach from independent control of multiple switching parameters to unified control based on phase difference and duty cycle parameters. This parameter transformation resolves the contradiction by reducing control complexity while maintaining PFC performance through optimized phase relationships between H-bridge switching sequences.
Solution Approach 2:
The control device is designed to perform multiple functions simultaneously: power transfer control, power factor correction, and harmonic reduction through a unified control architecture. By integrating these functions into a single control system that manages phase difference and duty cycle parameters, the patent achieves multi-functionality without increasing control complexity, thereby resolving the technical contradiction.
2Productivity
If switching sequences are optimized for power transfer, then power transfer efficiency improves, but control complexity increases
Solution Approach 1:
The patent extracts the essential control elements from complex switching sequences, identifying that only phase difference and duty cycle parameters are necessary for effective power transfer. By taking out and focusing on these critical parameters while eliminating redundant control variables, the system achieves high power transfer efficiency without proportionally increasing control complexity.
3Reliability
If phase shifts are introduced to improve PFC operation, then power factor correction improves, but switching sequence complexity increases
Solution Approach 1:
The control device pre-calculates and stores optimal phase difference and duty cycle parameter combinations for different operating conditions. By performing preliminary action to establish these parameter relationships, the system can achieve improved PFC performance through phase shifts without requiring complex real-time switching sequence generation, thereby reducing switching sequence complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution simplifies switch control, improves PFC performance, and enhances power transfer efficiency between the H bridges, reducing DC components and harmonics in the transformer current, thus improving overall converter operation.
Implementation Method 1
two H bridges coupled by a transformer
Data Source
AI summary
The present description concerns a method of controlling a converter including two H bridges (110, 12) coupled by a transformer (130), wherein: two switching sequences between states are respectively applied to the two bridges; one of the states of a first one of the sequences corresponds to a given direction of application of a voltage to the transformer by the bridge having the first one of the sequences applied thereto; the first one of the sequences varies during a same halfwave of an AC voltage (V1) across one of the bridges (110), so that: during at least a first period, switchings into and out of said one of the states occur in a same state of a second one of the sequences; and during at least a second period, switchings into and out of said one of the states occur in different states of the second one of the sequences.