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Project Background:
A client manufacturing 5kW string PV inverters was originally using silicon Schottky diodes (600V rating) in the front-end Boost circuit. Under high-temperature, high-irradiance conditions (ambient temperature exceeding 70°C), the reverse leakage current (IR) became excessive, causing a drop in overall system efficiency and preventing compliance with grid-connection efficiency requirements.
Product Model and Location
• SiC Schottky Diodes (650V/10A, TO-247 package)：
Replacing fast-recovery rectifiers as freewheeling diodes in MPPT boost circuits to provide high-efficiency rectification for PV modules.
• Fast-Recovery Diodes (FREDs)：
Used in the bridge rectifier circuit on the inverter output side.
• Problem Addressed:
Excessive switching losses impacting the inverter’s overall conversion efficiency.
• Project Outcomes:
Overall system efficiency improved by approximately 1.2%, meeting grid-connection efficiency certification requirements.
Thermal management burden significantly reduced; long-term system reliability enhanced.
