Dual Active Bridge Control for Leakage Inductance Variation
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Solution Overview
Problem
Existing power converters, such as dual active bridge (DAB) converters, face challenges in dynamically operating based on the varying leakage inductance of their transformers, which can lead to inaccuracies in efficiency and dynamic performance due to device-to-device and time-dependent variations.
Innovation Solution
A method and system for determining the leakage inductance of a DAB converter's transformer during normal operation, allowing the control circuitry to adjust the control scheme, including zero-voltage switching and gain scheduling, based on the measured leakage inductance to improve efficiency and dynamic performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a nominal control scheme based on nominal leakage inductance is used, then the device complexity is reduced, but the power conversion efficiency deteriorates when the actual leakage inductance deviates from the nominal value
Solution Approach 1:
The control scheme dynamically adjusts parameters (phase shift, duty cycle, switching frequency) based on the measured leakage inductance value. The system determines actual leakage inductance and modifies control parameters accordingly to maintain optimal power conversion efficiency across varying operating conditions and device tolerances.
Solution Approach 2:
The system measures the actual leakage inductance of the transformer and uses this feedback information to adjust the control scheme. By continuously monitoring and adapting to the actual leakage inductance value, the control system compensates for deviations from nominal values and maintains efficient operation.
2Ease of operation
If a fixed control scheme is used, then the ease of operation is improved, but the adaptability deteriorates when leakage inductance varies due to device-to-device or time-dependent variations
Solution Approach 1:
The control scheme transitions from a static, fixed configuration to a dynamic system that automatically adapts to changing leakage inductance conditions. The system continuously determines the actual leakage inductance and adjusts control parameters in real-time, enabling the converter to maintain optimal performance across varying operating conditions without manual intervention.
Solution Approach 2:
The system performs self-diagnosis and self-adjustment by measuring its own leakage inductance and automatically modifying its control parameters. This self-service capability eliminates the need for external calibration or manual adjustment, maintaining ease of operation while achieving high adaptability to leakage inductance variations.
3Productivity
If the leakage inductance is not determined during normal operation, then the productivity is maintained, but the measurement precision of leakage inductance is lost
Solution Approach 1:
The system continuously determines the leakage inductance during normal power transfer operation rather than requiring separate measurement phases. By integrating the leakage inductance determination into the ongoing power conversion process, the system maintains continuous productivity while obtaining accurate, up-to-date leakage inductance values for real-time control adjustments.
Data Source
AI summary
Systems and methods for operating a dual active bridge (DAB) converter include causing a current to flow through a transformer of the DAB converter, measuring the current, determining, based on the measured current, a leakage inductance of the transformer, and determining, based on the leakage inductance of the transformer, a control scheme for operating the DAB converter. In some embodiments, determining the leakage inductance includes determining a tank resistance of the transformer. In some embodiments, the control scheme includes a gain schedule, a zero-voltage switching scheme, or both, where the control scheme differs from a nominal control scheme, based on a nominal leakage inductance, and improves a power conversion efficiency or an accuracy of an output voltage as compared to the nominal control scheme.