RC-Drives

Cost-Optimized IGBT for Consumer Drive Application

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Another application that benefits from the low on-state losses or the RC-Drives is found in

Domestic Aircon systems: the ~1.5 kW BLDC compressor is driven by IGBTs switched by full

sinusoidal PWM hard switching at moderate switching frequencies of 5 to 8 kHz. Again in this

case a device optimized for low conduction losses provides an overall loss reduction.

However the trend observed in low power drives for outdoor and indoor fan of domestic Aircon

systems as well as industrial funs and pumps up to ~200W is to increase the PWM switching

frequency. The reason is twofold: on one side the size of the output filter can be reduced by

keeping the same current ripple. On the other side in small motor drives adopting sensor-less

FOC (Field Oriented Control), were a high dynamic control (torque and speed) of the PMSM

motor is required, the higher switching frequency allows to increase the sampling rate of current

and hence the accuracy of reconstructed rotor position.

In order to meet the rising demands of the IGBTs for the low power motor drive consumer

market, a new version of the RC-Drives IGBT is developed: the IGBT and diode losses are

optimized to reduce the inverter losses at switching frequencies of 18~20kHz. The new family is

called RC-DF, and released in the current classes from 2.5A to 15A in D-PAK packages.