Wide Bandgap DC-DC Converter for Vehicle Voltage Bridging
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Solution Overview
Problem
Micro hybrid vehicles require a DC-DC converter that can efficiently bridge between dual voltage electrical systems (e.g., 12V and 48V) while minimizing size and maximizing power density, and must withstand the vehicular environment, including high temperatures.
Innovation Solution
A DC-DC converter utilizing wide band gap semiconductor devices such as SiC and GaN transistors, with a power density of at least 4.17 watts/cc, operating within a size of at most 120 cc, and capable of delivering power outputs ranging from 500 watts to 3000 watts, with efficiencies of at least 80% or 90%, and using topologies like buck, half-bridge, full-bridge, or push-pull converters, operating at frequencies up to 2 MHz.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional semiconductor devices are used in the DC-DC converter, then the converter can be manufactured with standard processes, but the power density and efficiency are limited
Solution Approach 1:
The patent changes the material parameter of the semiconductor devices from conventional silicon to wide band gap materials (SiC, GaN). This material parameter change enables higher power density and efficiency while allowing operation at higher temperatures and switching frequencies, directly resolving the contradiction between power density and device complexity
Solution Approach 2:
The patent employs composite material strategy by integrating wide band gap semiconductor devices (SiC MOSFETs, GaN HEMTs) with traditional converter components. This combination leverages the superior electrical properties of wide band gap materials while maintaining the functional integrity of the overall converter system, achieving high power density without excessive complexity
2Volume of moving object
If the converter size is reduced to minimize space occupation, then the vehicle integration is improved, but the cooling requirements become more challenging
Solution Approach 1:
The patent changes the thermal parameter capability by using wide band gap semiconductor materials that can operate at higher junction temperatures (150-200°C vs. 125°C for silicon). This parameter change reduces the thermal management burden and allows smaller heat sinks and cooling systems, simultaneously achieving reduced converter volume and simplified cooling requirements
Solution Approach 2:
The patent converts the potentially harmful high temperature operation into a benefit by selecting wide band gap materials that thrive at elevated temperatures. These materials maintain their electrical properties at temperatures that would degrade conventional silicon devices, transforming the thermal challenge into an operational advantage that enables compact design
3Volume of moving object
If higher switching frequencies are used to reduce component size, then the converter volume is reduced, but the electromagnetic interference and losses increase
Solution Approach 1:
The patent changes the switching frequency parameter to operational ranges of 500 kHz to 2 MHz, significantly higher than conventional silicon-based converters. The wide band gap semiconductor devices enable these high switching frequencies with lower losses and reduced EMI, allowing substantial reduction in converter volume and component sizes while maintaining electromagnetic compatibility
Solution Approach 2:
The patent substitutes the traditional low-frequency, bulky magnetic and capacitive components with high-frequency equivalents enabled by wide band gap devices. This substitution replaces the need for large inductors and capacitors with smaller high-frequency components, reducing overall converter volume while the inherent fast switching characteristics of wide band gap materials naturally suppress EMI
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 solution provides efficient power conversion with high power density and reliability, suitable for micro hybrid vehicles, enabling increased fuel efficiency and supporting high power regeneration and electrification of new loads without excessive space or cooling requirements.
Implementation Method 1
The dc-dc converter includes wide band gap semiconductor devices
Data Source
AI summary
A method and apparatus for converting dc power from one voltage to another, in a mHEV includes an input filter, a converter circuit, and an output filter. the circuit is implemented with wide band gap devices, and may be a full bridge, half bridge, or push pull circuit. The size is preferably 120 cc, and the output power is preferably at least 500 W, 1 KW or up to 3 KW. The efficiency is preferably at least 80% or 90%, and the converter operates at a frequency of at least between 20 KHz and 2 MHz.