SiC Power Converter Inverter Module Stacking
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Solution Overview
Problem
Conventional Si IGBT modules for power converters in vehicles are limited in downsizing due to their size requirements, which restricts the miniaturization of inverters for both induction motors and permanent magnet synchronous motors, especially when multiple modules are mounted on a cooler in a planar manner.
Innovation Solution
The use of Silicon Carbide (SiC) switching elements and freewheeling diodes in semiconductor element modules, which allow for higher current density and reduced power losses, enabling the creation of more compact inverter designs by increasing the current rating per module while maintaining the same size, and integrating multiple switching elements into a single module.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If Si IGBT modules are mounted in a planar manner on a cooler, then the inverter can be constructed with conventional components, but the outer size of the inverter becomes large and downsizing is limited
Solution Approach 1:
The patent transitions from planar mounting of Si IGBT modules to three-dimensional integration using SiC MOSFET modules. The SiC modules are stacked vertically on the cooler rather than arranged in a planar fashion, utilizing the vertical dimension to reduce the horizontal footprint and overall inverter volume while maintaining cooling effectiveness.
Solution Approach 2:
The patent changes the material parameter from Si IGBT to SiC MOSFET, which enables higher current density and allows for more compact module design. This material parameter change fundamentally alters the power density achievable per unit volume, enabling significant downsizing of the inverter.
2Power
If multiple element modules are mounted on a cooler in a planar manner, then the inverter can handle required current ratings, but the area occupied by element modules becomes the limiting factor for downsizing
Solution Approach 1:
The patent arranges multiple SiC element modules in a vertical stack on the cooler rather than spreading them out in a planar configuration. This three-dimensional arrangement allows the inverter to handle high current ratings while occupying minimal horizontal area, directly resolving the contradiction between power capacity and footprint.
Solution Approach 2:
The patent uses SiC MOSFET modules which combine silicon carbide semiconductor material with integrated cooling structures. This composite approach allows multiple modules to be vertically integrated on a single cooler, maximizing power density while minimizing the area occupied by cooling infrastructure.
3Power
If Si IGBT modules are used for high current applications, then the required current rating can be achieved, but switching and conduction losses increase
Solution Approach 1:
The patent changes the semiconductor material from silicon (Si) to silicon carbide (SiC), which has superior electrical properties including higher breakdown voltage and lower on-resistance. This parameter change enables the SiC MOSFET modules to achieve the same or higher current ratings with significantly reduced conduction losses and improved switching efficiency.
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 use of SiC technology reduces switching and conduction losses, allowing for a significant reduction in the size and energy consumption of power converters while maintaining or improving performance, enabling the integration of higher current ratings within the same physical space.
Implementation Method 1
The use of Silicon Carbide (SiC) switching elements and freewheeling diodes in semiconductor element modules, which allow for higher current density and reduced power losses
Data Source
Figure 1
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Figure 4
AI summary
A power converter (100) for a vehicle according to an embodiment includes four semiconductor element modules (13a, 13b, 13c, and 13d) that each include silicon carbide (SiC) for a switching element (101) that performs switching operation and a freewheeling diode (102) that passes a freewheeling current and include circuits for three phases, each of the circuits being related to single-phase AC output and having arms each of which connects the freewheeling diode anti-parallel to the switching element, the arms being connected in series as circuits that perform three-phase AC output for driving one permanent magnet synchronous motor and a cooling unit (1) that cools the four semiconductor element modules.