Why GaN for Motor Drive Applications?
Switching speed is not necessarily a key issue for drives:
Typically want dv/dt <6V/ns (GaN can switch >10x faster)
– I=C dv/dt currents in motor windings can result in failures
– Corona and partial-discharge creates ozone and erodes insulation
– Common-mode currents forced through bearings, eroding races
Yet customers still want higher efficiency, increased density
Compressor drives have even more constraints:
– Very low leakage current mandates small Y-cap values (EMI)
– Newer “green” refrigerants have very high permittivity
Goal is to improve light-load efficiency (<25% of full power)
EU2013 directive for Energy Saving A+++ Class
Reducing losses also improves packaging density
APEC 2015 Seminar S17
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