Full-Bridge DC Converter Soft Switching for Lower Switching Loss
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Solution Overview
Problem
Existing direct current converters face challenges in achieving high power, high efficiency, and high power density due to significant switching losses in hard switching states, particularly in communication devices with smaller form factors.
Innovation Solution
The direct current converter employs a full-bridge inverter with controlled duty cycles and frequencies to ensure soft switching states for most switching devices, utilizing a resonant circuit and transformer configuration with specific capacitance and inductance ratios to minimize switching losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the direct current converter outputs larger power, then the power output increases, but the heat dissipation loss increases and conversion efficiency decreases
Solution Approach 1:
The patent changes the switching state parameter from hard switching to soft switching by introducing a resonant circuit. The resonant circuit creates zero-voltage or zero-current switching conditions, fundamentally changing the switching parameters to reduce switching losses and improve conversion efficiency while maintaining high power output capability
2Area of stationary object
If the plate area of the direct current converter is reduced, then the size decreases, but the heat dissipation capability decreases and efficiency is affected
Solution Approach 1:
The patent applies soft switching technology to change the operating parameters of the switching devices, enabling them to switch at zero voltage or zero current. This parameter change reduces switching losses and heat generation, allowing the converter to maintain high efficiency in a compact form factor with limited heat dissipation capability
3Ease of operation
If hard switching is used in all switching devices, then the control is simple, but the switching loss is high and efficiency is low
Solution Approach 1:
The patent segments the switching devices into different control groups: one switching device is controlled with adjustable duty cycle for voltage regulation, while other switching devices are controlled to achieve soft switching states. This segmentation allows different control strategies to be applied to different devices, reducing overall switching losses while maintaining manageable control complexity
Solution Approach 2:
The resonant circuit acts as an intermediary between the switching devices and the load, creating soft switching conditions for most devices. This intermediary component enables the switching devices to operate in soft switching states without requiring complex direct control, thus reducing switching losses while keeping the control system relatively simple
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 reduces switching losses, enhances efficiency, and stabilizes output voltage by ensuring most switching devices operate in soft switching states, improving overall converter performance.
Implementation Method 1
control a working frequency of the direct current converter to be a first working frequency, where an absolute value of a difference between the first working frequency and a resonant frequency of the resonant circuit is less than or equal to a threshold
Implementation Method 2
a transformer, a resonant circuit, and a rectifier module
Data Source
AI summary
A direct current converter includes a full-bridge inverter, a control module, a transformer, a resonant circuit, and a rectifier module. The full-bridge inverter includes a first switching device, a second switching device, a third switching device, and a fourth switching device. The control module adjusts a duty cycle of the first switching device, the second switching device, the third switching device, or the fourth switching device to a first duty cycle. The control module further controls a working frequency of the direct current converter to be a first working frequency, where an absolute value of a difference between the first working frequency and a resonant frequency of the resonant circuit is less than or equal to a threshold.