Parallel SiC MOSFET and Si IGBT Inverter Loss Reduction
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Solution Overview
Problem
Existing power conversion devices in electric-driven vehicles face challenges in reducing total losses due to the selective driving of silicon (Si) or silicon carbide (SiC) switching elements, which do not effectively minimize losses across varying current ranges.
Innovation Solution
An inverter system is designed with a SiC MOSFET module and a Si IGBT module connected in parallel, each with a dedicated control circuit that terminates driving when element temperatures exceed predefined thresholds, allowing both modules to operate when temperatures are within limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If only one set of switching elements (Si or SiC) is selectively driven, then the control is simplified, but the total losses cannot be reduced effectively
Solution Approach 1:
The patent divides the switching element system into two separate controllable modules: Si IGBT module and SiC MOSFET module. Each module has its own independent control circuit that can selectively drive its switching elements. This segmentation allows both modules to operate simultaneously or independently, enabling flexible loss optimization while maintaining control simplicity through modular architecture.
2Loss of energy
If Si switching elements are driven at high current, then losses are reduced in high current range, but overall efficiency is compromised at other current ranges
Solution Approach 1:
The system dynamically switches between Si IGBT and SiC MOSFET operation based on real-time current measurements. When high current is detected, the control circuit directs current through Si IGBTs which have lower conduction losses at high currents. When current drops to lower levels, the system transitions to SiC MOSFETs for optimal efficiency, thereby maintaining high overall productivity across all operating conditions.
Data Source
AI summary
This disclosure has an object of reducing the total losses of an inverter including a Si switching element and a SIC switching element that are connected in parallel. An inverter includes: a SiC MOSFET module; a Si IGBT module connected in parallel with the SiC MOSFET module; a SiC MOSFET module control circuit controlling the SiC MOSFET module; and a Si IGBT module control circuit controlling the Si IGBT module. The SiC MOSFET module control circuit terminates driving of the SiC MOSFET module when an element temperature of the SiC MOSFET module is higher than a first threshold. The Si IGBT module control circuit terminates driving of the Si IGBT module when an element temperature of the Si IGBT module is higher than a second threshold.