High precision constant velocity power off retract using switched capacitor technique

• Main Author: LUEBBE JUERGEN
• Format: Patent
• Language: English
• Published: 21.04.2005
• Edition: 7
• Subjects: CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORSOR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER; ELECTRICITY; GENERATION; INFORMATION STORAGE; INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORDCARRIER AND TRANSDUCER; PHYSICS

An apparatus for controlling an actuator having a moveable member and having a coil that influences movement of the member, by provision of a drive current to the coil in response to a target speed voltage signal. The apparatus includes a sensing unit ( 11 ) for sensing a voltage corresponding to the voltage across said coil and providing a first signal (BEMF) corresponding to the sensed voltage and indicative of the velocity of the moveable member. The apparatus further includes a generation circuit ( 13 ) for providing a second signal (TBEMF) indicative of a target voltage corresponding to a target velocity for the moveable member and a controller ( 12 ) receiving the first signal and the second signal and responsive thereto for determining a compensation signal characterized as an analog type response regulated to the target voltage for effectuating the target velocity.