IGBT/FRED Technology Improves AC Motor Control

Reported to increase useful ac-motor speed ranges by reducing dead time by a factor of three with 20% power loss, the company's process technology for insulated gate bipolar transistors (IGBTs) and fast recovery epitaxial diodes (FREDs) promises 70% faster turn-off times than previous generation devices. Using this process, devices are capable of 0.3 µs turn-off times, compared to 1.6 µs. Speed range is increased by reducing the inverter dead-time, by a factor of three, and by proportionally expanding the PWM duty cycle and the modulated frequency range. In addition, the new devices' gate characteristics have three times greater noise immunity and dv/dt induced turn-on current is reduced by a factor of twenty, compared to similar devices. Two IGBT/FRED devices, the IRGPSS60B120KD and IRGPSS40B120UD are available. The IRGPSS60B120KD for motor drives operates at frequencies up to 25 kHz and the IRGPSS40B120UD for UPS, welding and power-supply applications operates at frequencies up to 50 kHz. Price for either device is $8.32 each/10,000.INTERNATIONAL RECTIFIER, El Segundo, CA. (310) 252-7105.