Dual Active Bridge Triple-Phase Shift With Variable Inductor
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Dual active bridge (DAB) DC-DC converters face challenges in reducing root mean square (RMS) current and circulating current in high-power, high-current applications, where complex modulation schemes trade off effectiveness and flexibility, limiting usability in industrial applications.
Innovation Solution
A DAB converter with a variable inductor and a controller using triple-phase-shift control, allowing for zero-voltage-switching (ZVS) turn on and near zero current switching (ZCS) turn off in the high-voltage H-bridge, and reduced current switching or near ZCS turn off in the low-voltage H-bridge, operated in low, medium, and high power modes by adjusting inductance and phase shift ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If complex modulation schemes are used to reduce RMS current and circulating current, then current reduction effectiveness is improved, but modulation scheme flexibility and ease of digital implementation deteriorate
Solution Approach 1:
The patent applies dynamics by making the inductor inductance variable rather than fixed. The controller dynamically adjusts the inductance value based on operating conditions (low, medium, or high power mode) to optimize current reduction effectiveness while maintaining flexible and simple triple-phase-shift control implementation. This dynamic adaptation resolves the contradiction by allowing the system to achieve effective current reduction without being locked into complex fixed modulation schemes.
2Device complexity
If fixed inductance is used in the DAB converter, then device simplicity is maintained, but the ability to achieve zero-voltage-switching and near zero current switching across varying power levels deteriorates
Solution Approach 1:
The patent implements a variable inductor whose inductance can be dynamically adjusted based on power operating levels. This allows the DAB converter to maintain optimal switching performance (ZVS turn-on and near ZCS turn-off) across low, medium, and high power modes while keeping the overall device structure relatively simple. The variable inductance adapts to different operating conditions, resolving the contradiction between structural simplicity and switching reliability.
3Stability of the object's composition
If the DAB converter operates away from power mode boundaries, then stable operation is achieved, but the effectiveness of reducing RMS current and circulating current deteriorates
Solution Approach 1:
The patent uses dynamic adjustment of inductance and triple-phase-shift control to enable the DAB converter to operate effectively near power mode boundaries. By adaptively changing the inductance value and phase shift ratios based on the operating mode, the system can achieve both stable operation and effective current reduction even when operating near boundaries between low, medium, and high power modes, resolving the contradiction between stability and energy loss reduction.
Data Source
AI summary
A dual active bridge (DAB) converter includes a variable inductor and a controller configured or programmed to control the DAB converter using triple-phase-shift control. The controller can include a first proportional-integral controller to determine a parameter x based on comparison of a reference voltage and a measured voltage corresponding to either an HV voltage or an LV voltage; a voltage ratio calculator to determine a voltage ratio; a boundary calculator to calculate, based on the voltage ratio, a first boundary value corresponding to a boundary between low and medium power modes and a second boundary value corresponding to a boundary between the medium and high power modes; and a phase-shift-ratio calculator to determine phase shift ratios used in the triple-phase-shift control based on the parameter x, the voltage ratio, the first boundary value, and the second boundary value.