Bidirectional Active-Half-Bridge Resonant Converter for Wide-Range ZVS
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional DC-DC power converters face challenges with high current stresses, higher order harmonics, difficulty achieving zero-voltage switching (ZVS), and reduced power density due to complex control strategies and additional components, particularly in bi-directional operations.
Innovation Solution
An isolated bidirectional active-half-bridge resonant (AHBR) DC-DC power converter employs a dual compensation scheme with a novel controller design, utilizing a reduced number of switching devices and dual control loops to achieve efficient bi-directional power flow, zero-voltage switching, and high power density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional inductive impedance solutions are used, then DC-DC power conversion is achieved, but current stresses and higher order harmonics increase
Solution Approach 1:
The patent changes the impedance type from pure inductive to resonant by introducing a resonant capacitor in series with the transformer primary winding. This parameter change transforms the impedance characteristics, enabling soft switching operation and reducing current stresses and harmonics while maintaining power conversion capability.
Solution Approach 2:
The patent utilizes resonant oscillations at a specific frequency determined by the resonant inductor and capacitor. By operating at this resonant frequency, the system achieves zero-voltage switching conditions, which reduces current stresses and harmonic content in the power conversion process.
2Loss of energy
If resonant impedance solutions (LLC) are used, then power conversion efficiency improves, but device complexity and control difficulty increase
Solution Approach 1:
The patent extracts and eliminates unnecessary components from conventional LLC resonant converters. Specifically, it removes the need for DC blocking capacitors and additional filter capacitors by using a full-bridge switching network with synchronized switching, thereby reducing device complexity while maintaining high efficiency.
Solution Approach 2:
The patent makes the resonant capacitor serve multiple functions: it creates the resonant impedance for efficient power transfer, enables zero-voltage switching, and eliminates the need for separate DC blocking capacitors. This multi-functionality reduces overall device complexity while maintaining high conversion efficiency.
3Adaptability or versatility
If additional components are added for bi-directional operation, then bidirectional power flow capability is achieved, but power density decreases
Solution Approach 1:
The patent implements bi-directional power flow by dynamically controlling the switching states of the full-bridge network. The same resonant circuit and transformer are used in both directions, with switching devices dynamically adjusted to achieve forward and reverse power transfer, eliminating the need for additional dedicated components for each direction.
Solution Approach 2:
The resonant capacitor and full-bridge switching network serve universal functions for both forward and reverse power flow. The same components handle bidirectional operation through controlled switching, avoiding the need for separate DC blocking capacitors or additional filter elements for each direction, thereby maintaining high power density.
4Loss of energy
If zero-voltage switching is achieved, then switching losses are reduced, but current ripple increases requiring larger output capacitors
Solution Approach 1:
The patent employs a control system that monitors the resonant current and switching states to maintain zero-voltage switching conditions. The feedback control adjusts switching timing based on the resonant oscillation phase, ensuring ZVS is achieved while managing current ripple characteristics to minimize output capacitor requirements.
Solution Approach 2:
The patent optimizes the resonant frequency and switching frequency parameters to achieve zero-voltage switching while minimizing current ripple. By carefully selecting and adjusting these parameters, the system achieves soft switching without requiring excessively large output capacitors, balancing switching loss reduction with ripple management.
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 AHBR converter achieves efficient high-density power conversion with simplified control strategies, reduced ripple currents, and minimized component count, ensuring zero-voltage switching across a wide range of operating conditions.
Implementation Method 1
a resonant inductor, a resonant capacitor, and a first winding of a transformer are connected in series between the first central node and the first negative DC node
Implementation Method 2
a first winding of a transformer are connected in series between the first central node and the first negative DC node
Data Source
AI summary
An isolated bidirectional active-half-bridge resonant DC-DC power conversion apparatus employs dual control strategies to regulate bi-directional power flow between two DC sources. The apparatus includes a first half bridge switching network configured to convert a first DC power to an AC power. A series resonant impedance transfers the AC power to a first winding of a transformer. A first inductor and a second inductor are connected in series across a second winding of the transformer and form a positive DC node. A second half bridge switching network is connected in parallel with a first clamping capacitor, with a central node connected to the first end of the second winding. A third half bridge switching network is connected in parallel with a second clamping capacitor, with a central node connected with the second end of the second winding. The clamping capacitors are connected with a negative DC node.