T-Type EV Inverter Power Module Layout for Low Harmonics
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Solution Overview
Problem
Two-level inverters used in electric vehicles generate high levels of harmonics and have relatively low efficiency at higher switching frequencies, while existing three-level inverters face challenges with thermal performance, large commutation loops, and noise coupling due to high inductances.
Innovation Solution
A three-level inverter with a T-type arrangement featuring double side cooling and symmetrical gate routing of semiconductor dies, arranged in drain-down or source-down configurations, reduces loop inductance and enhances electrical balance for improved efficiency and reduced harmonics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If two-level inverters are used, then the structure is simple and production cost is low, but harmonics level is high and efficiency is low at higher switching frequencies
Solution Approach 1:
The patent divides the single switching stage of a two-level inverter into two cascaded switching stages, creating a three-level inverter structure. This segmentation allows the output voltage to have three distinct levels (positive DC, zero, negative DC), which reduces harmonics by providing a more refined voltage waveform that better approximates a sine wave.
Solution Approach 2:
The patent transitions from a two-level voltage structure to a three-level voltage structure by adding an intermediate neutral point dimension. This dimensional change in the voltage output enables lower harmonics and improved electromagnetic compatibility while maintaining reasonable structural complexity.
2Object-generated harmful factors
If three-level inverters are used, then harmonics are reduced and efficiency is improved, but thermal performance deteriorates and commutation loops become large
Solution Approach 1:
The patent merges the cooling functions for multiple power modules into a single shared heat sink structure. This consolidation allows thermal management resources to be efficiently allocated across all power modules, improving overall thermal performance while reducing the total volume and complexity of cooling systems.
Solution Approach 2:
The shared heat sink serves multiple power modules simultaneously, providing a universal thermal management solution. This multi-functional approach enables a single cooling component to handle heat dissipation for the entire inverter system, improving thermal performance without proportionally increasing system complexity.
3Object-generated harmful factors
If three-level inverters are used, then harmonics are reduced, but commutation loops become large and noise coupling increases
Solution Approach 1:
The patent implements local optimization of the circuit layout by carefully arranging the T-type power module components to minimize commutation loop areas. The local quality of the PCB trace routing and component placement is optimized to reduce parasitic inductances and electromagnetic noise coupling, allowing the three-level inverter to achieve low harmonics without excessive noise.
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 proposed inverter design achieves lower harmonics, better electromagnetic interference emissions, and improved thermal performance, allowing faster switching times and reduced noise coupling.
Implementation Method 1
a first heat sink on a first side of the first power module; and a second heat sink on a second side of the first power module
Implementation Method 2
double side cooled power module
Data Source
AI summary
A system including an inverter to convert DC power from a battery to AC power to drive a motor, wherein the inverter includes a first power module including a first switch electrically connected to a positive DC power tab and an AC power tab, a second switch electrically connected to a negative DC power tab and the AC power tab, and two switches electrically connected to a neutral power tab and the AC power tab.