Three-Level DC Converter With Resonant Soft Switching
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Solution Overview
Problem
Conventional direct current converters have high switching losses and low efficiency due to their large volume and reliance on hard-switching states, necessitating high-voltage power switching components that reduce reliability.
Innovation Solution
A direct current converter with a three-level power switching circuit and resonant circuit, controlled by a controller to manage voltage stress on power switching components, ensuring they operate at half the input voltage during charging and discharging processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional direct current converters use magnetic elements (inductor and transformer) to transfer energy, then energy transfer is achieved, but the volume is large and power density is low
Solution Approach 1:
The patent replaces the conventional magnetic element-based energy transfer system (inductor and transformer) with a resonant circuit system. This substitution eliminates the need for large magnetic components, thereby reducing the overall volume of the direct current converter while maintaining effective energy transfer capability through resonant oscillation between the resonant inductor and resonant capacitor.
2Loss of energy
If conventional direct current converters work in hard-switching state, then switching control is simple, but switching loss is large and efficiency is low
Solution Approach 1:
The patent utilizes resonant vibration in the resonant circuit to enable soft-switching operation. By operating at the resonant frequency of the LC circuit, the switching transitions occur when current and voltage are naturally at or near zero, eliminating hard-switching losses and significantly reducing energy dissipation during switching events.
3Reliability
If power switching components withstand high direct current input voltage, then voltage blocking capability is sufficient, but component reliability is reduced
Solution Approach 1:
The patent employs a three-level power switching circuit that segments the high voltage handling into multiple stages. The circuit structure divides the voltage stress across multiple power switching components, so that each component only needs to withstand a portion of the total direct current input voltage rather than the full high voltage, thereby improving reliability while maintaining adequate voltage blocking capability.
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
Reduces voltage stress on power switching components to half the input voltage, improving reliability and efficiency by enabling soft-switching operation.
Implementation Method 1
Energy is transferred through a resonant circuit 10 (including a resonant inductor and a resonant capacitor)
Implementation Method 2
Photovoltaic power generation is a technology that uses a photovoltaic effect of a semiconductor interface to convert light energy into electric energy
Data Source
AI summary
A direct current converter includes a three-level power switching circuit, a resonant circuit, and a controller. An output voltage at an output end of the three-level power switching circuit is used to charge the resonant circuit. The controller is configured to control power switching components in the three-level power switching circuit, so that when the resonant circuit performs charging or discharging at one half of a direct current voltage, one of the power switching components is connected to a current loop of the resonant circuit, and when the resonant circuit performs charging or discharging at the direct current voltage, two of the power switching components are connected to the current loop of the resonant circuit. By using the direct current converter, a voltage borne by the power switching component in the direct current converter during current conversion can be reduced, thereby improving reliability of the direct current converter.