Resonant Converter Discharge Control for Capacitive Load Protection

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Solution Overview

Problem

Current discharging circuits in resonant converters have a high damage rate due to the inability to effectively discharge voltage when the load characteristic is a capacitance-voltage characteristic, leading to potential damage to the circuit.

Innovation Solution

A resonant converter system with a controller that determines the load characteristic as purely resistive or capacitance-voltage based on output voltage trends and equivalent/actual capacitance values, controlling the discharging circuit to open or close accordingly, thereby preventing damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a discharging circuit is arranged at the output end to discharge voltage, then the safety of the electronic device is improved, but the complexity of the device increases

Engineering Contradiction:
Improvesafety of electronic deviceVSAvoidcomplexity of discharging circuit
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent makes the discharging circuit multi-functional by enabling it to operate in different modes (closed for discharge, open for protection) based on load characteristics. This universal approach allows a single discharging circuit design to handle multiple scenarios safely, reducing the need for additional specialized components or circuits for different load types, thereby limiting the increase in device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 system reduces the damage rate of discharging circuits by accurately determining load characteristics and adjusting the discharging process, ensuring safe and reliable capacitor discharge without the need for anti-reverse diodes, thus reducing costs.

Implementation Method 1

A resonant converter is a resonant circuit composed of an inductor and a capacitor to implement resonance at a specific frequency, thereby implementing electric energy conversion and control.

Methodology Applied
Scientific EffectResonance: Resonance

Implementation Method 2

voltage stored on the capacitor in the resonant converter is discharged after the resonant converter stops operating, to prevent the voltage stored on the capacitor from damaging the electronic device

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP4672582A1Resonant converter, method for controlling resonant converter, and related device
Publication Date: 2025.12.31 SUNGROW CHARGING TECH CO LTD
  • EP4672582A1 patent drawingFigure 1~2a
  • EP4672582A1 patent drawingFigure 2b~3
  • EP4672582A1 patent drawingFigure 4~5

AI summary

A resonant converter, a method for controlling a resonant converter, and a related apparatus are provided. The resonant converter includes: a first resonant conversion circuit, a second resonant conversion circuit, a switching module, a discharging circuit, and a controller. The controller outputs a first control signal to the discharging circuit in a case that a load characteristic of the resonant converter is a purely resistive characteristic; and outputs a second control signal to the discharging circuit in a case that the load characteristic of the resonant converter is a capacitance-voltage characteristic. The first control signal is configured for closing the discharging circuit, and the second control signal is configured for opening the discharging circuit.