Bidirectional DC-DC Resonant Converter with Dynamic Reconfiguration
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Solution Overview
Problem
Existing bi-directional DC-DC resonant converters face inefficiencies due to increased power losses from additional inductors, and they fail to adapt optimally to changing voltage ratios during battery charging and discharging in renewable power systems.
Innovation Solution
A bi-directional DC-DC resonant converter that switches between two different resonant circuits with distinct resonant frequencies and DC gains, utilizing a transformer with a configuration switch, resonant inductor, and magnetizing inductor to maintain optimal voltage ratios during both charging and discharging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an additional inductor Lnew is added to achieve controlled voltage level in both directions, then bi-directional voltage control is improved, but power losses increase and power efficiency decreases
Solution Approach 1:
The patent removes the additional inductor Lnew from the circuit topology. Instead of adding components to achieve bi-directional control, the invention uses the existing resonant tank components (resonant inductor Lr, magnetizing inductor Lm, and resonant capacitor Cr) in different configurations to achieve voltage control in both power flow directions, thereby eliminating the source of increased power losses
Solution Approach 2:
The resonant tank components serve multiple functions: they provide resonance for soft switching, enable voltage transformation, and facilitate bi-directional power flow control. The magnetizing inductor Lm and resonant inductor Lr work together in different configurations to achieve voltage level control in both charging and discharging modes without requiring dedicated additional inductors
2Adaptability or versatility
If a fixed resonant circuit configuration is used, then device complexity is reduced, but the converter cannot adapt to changing voltage ratios during battery charging and discharging
Solution Approach 1:
The patent implements dynamic reconfiguration of the resonant tank circuit using switching elements. The converter can switch between different resonant circuit configurations (different combinations of Lr, Lm, and Cr) depending on the power flow direction and voltage ratio requirements. This dynamic adaptation allows optimal performance during both battery charging and discharging without requiring a completely separate circuit for each mode
Solution Approach 2:
The invention changes the effective inductance and capacitance parameters of the resonant tank by reconfiguring the connections of Lr, Lm, and Cr. This parameter reconfiguration adjusts the resonant frequency and gain characteristics to match the optimal voltage ratio for the current operating mode (charging or discharging), enabling adaptation without adding complex control hardware
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
This approach enhances power efficiency by adjusting resonant frequencies and gains based on power flow direction, optimizing voltage ratios and reducing power losses, thereby improving performance in battery charging and discharging applications.
Implementation Method 1
a resonant tank device having first and second primary resonant tank terminals defining a primary resonant tank voltage and first and second secondary resonant tank terminals defining a secondary resonant tank voltage
Implementation Method 2
a transformer device having primary transformer terminals and secondary transformer terminals
Data Source
Figure 1a~1c
Figure 2a
Figure 2b
AI summary
The present invention relates to a bi-directional DC-DC resonant converter (1) with bi-directional voltage control. A resonant tank device (RTD) has first and second primary resonant tank terminals (a1, a2) defining a primary resonant tank voltage (Ua) and first and second secondary resonant tank terminals (b1, b2) defining a secondary resonant tank voltage (Ub). The resonant tank device (RTD) comprises a configuration switch (RS) for configuration of the converter (1) between a first state, in which power is transferred from the secondary converter terminals (TCb1, TCb2) to the primary converter terminals (TCa1, TCa2), and a second state, in which power is transferred from the primary converter terminals (TCa1, TCa2) to the secondary converter terminals (TCb1, TCb2). A first gain Gres1 when operating at a first series resonance frequency (ωres1) in the first state is different from a second gain (Gres2) when operating at a second series resonance frequency (ωres2) in the second state.