Resonant DC-DC Converter Capacitor Overload Protection
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Solution Overview
Problem
Existing DC-DC converters in electric and hybrid motor vehicles face challenges in protecting resonance capacitors from overloads, particularly due to large voltage amplitude variations, which can lead to component deterioration and system failure, with existing solutions being costly and inflexible.
Innovation Solution
An electrical system with a resonant DC-DC converter that includes a rectifier to convert alternating voltage to pulsed rectified voltage, a filter to improve signal quality, and a detection module to determine maximum and minimum voltage thresholds for resonance capacitors, allowing for adaptive protection and automatic shutdown in case of overload.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ultra-fast diodes are used to protect resonance capacitors from overload, then the capacitors are protected from voltage overloads, but the cost increases significantly and the circuit structure becomes more complex
Solution Approach 1:
The patent replaces the mechanical/electrical protection mechanism (ultra-fast diodes) with a control system that uses sensing elements to detect voltage conditions and electronically controlled switching elements to provide protection. This substitution allows for more flexible and adjustable protection without the inherent limitations of passive diode-based approaches.
Solution Approach 2:
The invention enables adjustable protection thresholds through the control system, allowing the voltage thresholds for activation of switching elements to be modified based on operating conditions. This contrasts with fixed-threshold diode-based protection and allows optimization across different operating scenarios.
2Reliability
If ultra-fast diodes are used to short-circuit resonance capacitors, then voltage overload is prevented, but the diodes cannot short-circuit at the same time and the threshold voltage is not adjustable
Solution Approach 1:
The patent implements a feedback mechanism where sensing elements continuously monitor the voltage across resonance capacitors and provide signals to the control system. This feedback enables real-time detection of overload conditions and allows the control system to activate protection mechanisms at precisely the right moment, with adjustable thresholds adapted to different operating conditions.
Solution Approach 2:
The invention transitions from static, fixed-threshold protection (diodes) to dynamic, adjustable-threshold protection through electronically controlled switching elements whose activation thresholds can be modified in real-time based on operating conditions, enabling adaptable protection across varying scenarios.
3Reliability
If resonant current measurement is used to detect overload, then protection is provided, but the solution remains costly and does not fully address the limitations of existing approaches
Solution Approach 1:
The patent introduces sensing elements as intermediaries that indirectly detect overload conditions by monitoring voltage across resonance capacitors rather than directly measuring resonant current. This intermediary approach provides equivalent protection information while enabling a different, potentially more cost-effective implementation path through voltage-based detection and electronic control.
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
Effectively detects and prevents overloads in resonance capacitors, protecting the converter components and preventing system failures, while being adaptable to varying conditions and reducing the need for costly ultra-fast diodes.
Implementation Method 1
a resonant inductor (Lr), two resonance capacitors (Cr/2), and a transformer (Tr). The converter circuit (10) comprises a first circuit (10-1) and a second circuit (10-2), making it possible in particular to obtain a square-wave alternating voltage
Implementation Method 2
a rectifier (20), connected to the output of said converter circuit (10). The rectifier (20) makes it possible to convert a square alternating voltage into a pulsed rectified voltage
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
The present invention relates to an electrical system for converting one DC voltage into another DC voltage, comprising: • a resonant DC-DC converter (1) including an LLC converter circuit, • a control unit (TN) including: ∘ a first module for determining (TN1) the effective value of the resonant current (Ir_RMS) from a measurement of the output current (Is), ∘ a second module for determining (TN2) a maximum value (Vr_max) of the voltage across each resonant capacitance (Cr/2) and a minimum value (Vr_min) of the voltage across each resonant capacitance (Cr/2) from the effective value of the resonant current (Ir_RMS), ∘ a comparison module (TNC), ∘ a cutoff element (UP) configured to stop the operation of the resonant DC-DC converter (1) in case of overload.