The PWR-82520R Space Motor Drive is intended to drive 3-phase brushless dc motors and is available in 1-A, 3-A, and 10-A current ratings. Completely self contained, the radiation-hardened unit includes command amplifiers, pulse width modulator (PWM), commutation control, tachometer, current sense amplifier, gate drive, and power MOSFET drive stage.

Using a control technique called four-quadrant control, it achieves 3% current linearity and current regulating accuracy of 5% while maintaining holding torque over the input range even at zero commanded input. "By eliminating zero input deadband, you don't lose control and you get a much finer loop control as you approach zero," explains Mike Pitka, product marketing manager for motor drives and controls. "Instead of operating as a three-phase bridge, this type of control operates as a series of 'H' bridges. It's very linear through zero."

With programmable gain and compensation, the command amplifier lets users match loop performance to the system and motor. An adjustable PWM switches from 10-100 kHz for operation with low inductance motors. Hall sensors located in the motor provide commutation and tachometer signals. The gate drive, optimized for radiation performance and noise immunity, provides a controlled signal to the rad-hard MOSFET output stage.

Available in plug-in or surface-mount package, these drives are targeted at antenna and solar array positioning, reaction and momentum wheels, pump motors for fuel and fluid control, fan and compressor motors for environmental control systems, radar positioning, and thrust vector control.Additional Details...Contact Mike Pitka, Data Device Corp., 105 Wilbur Place, Bohemia, NY 11716-2482; Tel: (631) 567-5600; www.ddc-web.com