Online Impedance Detection for Dual-Active Bridge Converters
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Solution Overview
Problem
Existing methodologies for determining the coupling impedance between primary and secondary converter bridges in dual-active bridge DC-DC converters are inaccurate due to parasitic components, leading to sub-optimal and unsafe operation, and require additional sensing architectures or trial-and-error methods.
Innovation Solution
An online impedance detection method using a mathematical model of Zero Voltage Switching (ZVS) boundaries, which determines the magnetic coupling coefficient by analyzing the phase shift error and stagnation of DC bus current, allowing precise parameterization of coupling impedances without additional sensing architectures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If additional sensing architectures are used to determine coupling impedance, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The dual-active bridge converter uses its own existing control signals and voltage/current measurements to determine coupling impedance parameters. The controller analyzes the relationship between switching signals and electrical parameters during normal operation, eliminating the need for separate sensing architectures while achieving accurate parameter determination.
Solution Approach 2:
The patent introduces mathematical models and signal processing algorithms as intermediaries to extract coupling impedance information from existing operational data. By processing the relationship between control signals and electrical responses through these intermediary computational methods, the system achieves precise measurement without additional physical sensors.
2Device complexity
If trial-and-error methods are used to determine coupling impedance, then device complexity is reduced, but productivity decreases
Solution Approach 1:
The system performs preliminary determination of coupling impedance parameters during the initial operation or setup phase using mathematical modeling. By pre-calculating and storing these parameters based on manufacturer data and operational characteristics, the system avoids time-consuming trial-and-error adjustments during actual operation, significantly improving productivity.
Solution Approach 2:
The controller continuously monitors electrical parameters and uses feedback mechanisms to refine and update coupling impedance determinations. By comparing actual operational data with model predictions and adjusting parameters accordingly, the system achieves rapid and accurate parameter determination without repeated trial-and-error cycles.
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
Enables precise and safe operation of dual-active bridge DC-DC converters by accurately determining coupling impedances, reducing the risk of system failure and improving reliability, while avoiding the need for additional sensing circuits.
Implementation Method 1
a secondary side circuit which is connected to the primary side circuit via a reactor and magnetically coupled with the primary side circuit via a transformer
Data Source
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AI summary
Various embodiments provide a detection method. The detection method includes: determining at least one of an impedance of the converter or a magnetic coupling coefficient of the converter based on an online detection of ZVS (Zero Voltage Switching) boundary operating conditions using the effect of inherent switching dead time. and a subsequent integration of the test data into a mathematical description of these ZVS boundaries.