U.S. Philips Corporation

Gerardus A Van Beijsterveld

Nicolaas Johannes Damstra

Marinus C Van Buul

Henricus C Buthker

A motor control device controls an electric 3-phase brushless d.c. motor (10) having a magnetic rotor (15) and three windings (11, 12, 13). The motor control device includes a detection unit (20) adapted to generate a commutation signal (21) on the basis of the back-emf voltage produced in the windings (11, 12 and 13). The motor control device further includes an output stage (30) having a first terminal (31) and a second terminal (32) for the connection of a power-supply source, outputs (33, 34, 35) for the connection of the windings (11, 12 and 13) and a number of semiconductor elements (36) for selectively coupling the terminals (31, 32) to the outputs (33, 34, 35) in dependence upon the commutation signal (21). The motor control device further includes a phase detector (40) adapted to generate a phase-error signal (43) which is representative of the phase difference between a sensor signal and a reference signal. The output stage (30) is arranged in series with a controllable power-supply stage (50) adapted to feed a bidirectional current (I) through the windings (11, 12, 13) via the outputs (33, 34, 35). The current (I) is controlled in dependence upon the phase-error signal (43) for driving the rotor (15) in a controlled manner, or for actively braking said rotor.

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Breda, Netherlands

Gerardus A Van Beijsterveld