Hybrid Si-SiC Converter Modulator for Switching Loss Reduction
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Solution Overview
Problem
Silicon-based power electronic devices experience significant switching losses at high frequencies, limiting their efficiency and performance, while silicon carbide-based devices offer lower switching losses but are costly, necessitating a hybrid approach to leverage both technologies effectively.
Innovation Solution
A hybrid converter system that combines silicon-based and silicon-carbide based power electronic devices, switching silicon-based devices at fundamental frequencies and silicon-carbide devices at higher frequencies, with a processor-controlled modulation to achieve efficient voltage conversion, and incorporates a snubber capacitor to reduce switching losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If silicon-based power electronic devices are used, then cost is reduced, but switching losses increase significantly at high frequencies
Solution Approach 1:
The converter system is segmented into two distinct parts: silicon-based power electronic devices for cost-effective operation and silicon carbide-based power electronic devices for high-frequency switching. This segmentation allows each technology to operate in its optimal frequency range, reducing overall switching losses while controlling costs.
Solution Approach 2:
The invention changes the switching frequency parameter for different device types. Silicon-based devices operate at fundamental frequencies (lower frequencies) where they exhibit acceptable losses, while silicon carbide devices operate at higher switching frequencies where their low loss characteristics provide benefit. This parameter differentiation resolves the contradiction between cost and switching losses.
2Loss of energy
If silicon carbide-based power electronic devices are used, then switching losses are reduced, but manufacturing cost increases
Solution Approach 1:
Silicon carbide-based power electronic devices are deployed locally in specific positions within the converter system where high-frequency switching is required and provides maximum benefit. This localized application of expensive technology minimizes overall cost while achieving the desired reduction in switching losses at critical points in the system.
Solution Approach 2:
The invention changes the operating frequency parameter for silicon carbide devices to higher frequencies where their low switching loss characteristics provide maximum benefit. By operating SiC devices at higher frequencies rather than uniformly across all devices, the system achieves superior efficiency while limiting the number of expensive components required.
3Speed
If silicon-based devices switch at high frequencies, then voltage conversion speed improves, but switching losses become excessive
Solution Approach 1:
The switching function is segmented between two device types: silicon-based devices handle fundamental frequency switching and silicon carbide devices handle high-frequency switching. This segmentation enables the system to achieve high voltage conversion speed through the SiC devices without subjecting the silicon-based devices to excessive switching losses.
Solution Approach 2:
The invention changes the switching frequency parameter based on device type and operational requirements. Silicon-based devices operate at fundamental frequencies to avoid excessive losses, while silicon carbide devices operate at higher frequencies to achieve fast voltage conversion. This differential parameter assignment resolves the contradiction between speed and losses.
Data Source
AI summary
The present disclosure is directed to a system and method for modulating a voltage output of a hybrid converter system having first and second set of Si-based power electronic devices coupled to first and second voltage source, respectively, and a first set of SiC-based power electronic devices coupled to the first and second sets of Si-based power electronic devices. The method includes switching between operational states of the hybrid converter system based on a desired voltage output, wherein each operational state includes one of the Si-based power electronic devices from the first and second sets of Si-based power electronic devices and one of the SiC-based devices from the first set of SiC-based power electronic devices being switched on and the remaining power electronic devices being switched off. Each SiC-based power electronic device of the first set of SiC-based power electronic devices switches at a higher frequency as compared to each Si-based power electronic device of the first and second sets of the Si-based power electronic devices.