A permanent magnet synchronous motor having multiple-phase armature windings and a rotor is subjected to sensor-less control. Phase voltages are generated in response to voltage command values. The generated phase voltages are applied to the armature windings. Phase currents through the armature windings are detected. The detected phase currents depend on the voltage command values. An angular position and an angular velocity of the rotor are calculated from the detected phase currents. The voltage command values are adjusted in response to the calculated angular position and the calculated angular velocity of the rotor to implement feedback control of the motor. An angular velocity of the rotor is estimated from a time-domain variation in the calculated angular position of the rotor. A determination is made as to whether or not the calculated angular velocity of the rotor and the estimated angular velocity of the rotor are substantially equal to each other. The calculated angular position of the rotor is changed by a predetermined phase value and is thereby corrected when it is determined that the calculated angular velocity of the rotor and the estimated angular velocity of the rotor are not substantially equal to each other.

Method and apparatus for sensor-less control of permanent magnet synchronous motor

A sensor-less control apparatus is designed for a permanent magnet synchronous motor having multiple-phase armature windings and a rotor. The sensor-less control apparatus includes a first device for calculating a rotational angle and an angular velocity of the rotor from phase currents and phase voltages of the armature windings. A second device is operative for controlling energizations of the armature windings in response to the rotational angle and the angular velocity calculated by the first device. A third device is operative for correcting the rotational angle calculated by the first device into a correction-resultant rotational angle and informing the second device of the correction-resultant rotational angle, and for feeding back information of the correction-resultant rotational angle to the first device. A fourth device contained in the third device is operative for low-pass-filtering the rotational angle calculated by the first device and changing the rotational angle into a filtering-resultant rotational angle. A fifth device contained in the third device for, in cases where a previous rotational angle outputted from the fourth device and the rotational angle calculated by the first device are not in a same period, correcting the previous rotational angle into a correction-resultant previous rotational angle and informing the fourth device of the correction-resultant previous rotational angle.

Sensor-less control apparatus for permanent magnet synchronous motor

This invention relates to a quake-absorbing device and installation method therefor. A conventional quake-absorbing device has been known as described, for example, in Japanese Patent Application Public Disclosure No. 2000-14472(A). This conventional quake-absorbing device comprises an upper base secured on an object to be protected from an earthquake or other vibrations, a lower base on a floor, upper and lower upcurved rails attached to the upper and lower bases, and rollers which moves rotatively along the upper and lower rails by rolling. The upper and lower rails are vertically opposed to each other across the rollers at the angle of approximately 90 degrees so as to be arranged in the plane form of a substantially square. However, in a case where computer-associated equipment such as a computer server is protected from seismic waves, wiring such as communication and electric circuits is often laid on a floor and connected to the equipment. The wire or cable possibly comes into contact with the quake-absorbing device, consequently to degrade the quake-absorbing performance of the quake-absorbing device. Thus, it has been very difficult to apply the quake-absorbing device to the equipment having the wiring connected thereto. To remedy the disadvantage suffered from the conventional quake-absorbing device, the present invention provides a quake-absorbing device having improved quake-absorbing performance and a method capable of installing the quake-absorbing device without suspending the operation of existing protected object. The quake-absorbing device of the invention is distinctively provided with an opening passage for permitting the wiring cables connected to the protected object to pass therethrough so as not to bring the wiring cables into contact with the quake-absorbing device, thereby to achieve high quake-absorbing performance.

Base isolation device and method of installing base isolation device

This invention relates to a motor current phase delay compensating method and apparatus thereof enabling the driven system to efficiently operate by compensating current phase delay of the stator coil winding such that an alternating current servo motor for driving a FA system, a CNC, or a robot for industry generates maximum torque. An output signal of an A/D converter and a rotational direction discriminating signal of an alternating current servo motor are received whereby a phase delay value with respect to the speed is generated. The phase delay value and an output signal from the A/D converter are summed whereby a phase delay compensation amount is computed to compensate the phase delay amount. The phase delay compensation amount and an output from the speed PI controller are respectively received whereby U-phase and V-phase analog current reference instruction values area generated. The U-phase and V-phase analog current reference instruction values are summed and then inverted whereby a W-phase analog current reference instruction value is generated and thereby current delay flowing to the stator coil winding is properly compensated.

Motor current phase delay compensating method and apparatus thereof

PURPOSE:To detect an angle of inclination at a position of inspecting ICs accurately by providing an arithmetic device to correct errors of an angle of inclination for an optical axis in an IC inspection attitude from two silhouette images as connected to one set of cameras for taking silhouette images. CONSTITUTION:Two cameras 13 and 14 and two lighting devices 11 and 12 are positioned at four parts separated at an equal distance on the same circumference viewed in plane while being located near surrounding sides of ICs 2. In operation, a lead 2a of an IC 2 and a molded underside edge 2b are taken with the cameras 13 and 14. Then, an arithmetic device (not illustrated) is connected to the two cameras 13 and 14 to correct errors in an angle of inclination at a position of inspecting ICs. This enables accurate detection of an angle of inclination at the position of inspecting ICs from two pieces of image information during the stoppage of conveying ICs.

Iketani Susumu

Papers

Soil pressure opposing balance apparatus for embedded pipe