Abstract: A control apparatus for a brushless DC motor that rotatably drives the brushless DC motor including a rotor having a permanent magnet, and a stator having stator windings of a plurality of phases that generate a rotating magnetic field for rotating the rotor, by a current passage switching device constituted by a plurality of switching elements and performing successive commutation of current to the stator windings. The control apparatus includes: an angular error calculation device for calculating a sine value and a cosine value of an angular difference between an estimated rotation angle with respect to the rotation angle of the rotor and an actual rotation angle, based on a line voltage that is a difference between phase voltages of the plurality of phases on an input side of the stator winding and phase currents of the plurality of phases; and an observer for calculating the rotation angle of the rotor based on the sine value and the cosine value of the angular difference.

Abstract: A method of correcting a pointing position of a pointer rotated by a stepper motor includes the steps of: performing a prereset operation in which the pointer is rotated to a reset operation starting position that represents a pointing position of the pointer which is shifted by a predetermined amount in a plus direction of a scale from a reset position where a pin which is rotated in conjunction with a rotation of the pointer abuts against a fixed stopper; after the prereset operation, performing a reset operation in which the pointer is rotated in a minus direction of the scale to the reset position; and after the reset operation, performing a correcting operation in which the pointer is rotated in the plus direction up to a reference pointing position which is indicated by previously stored reference pointing positional information.

Abstract: A carriage driving apparatus that drives a carriage of a printer or the like by a motor and a motor control method for controlling the motor can substantially eliminate variation in control accuracy among individual apparatuses. Each set of various parameters are determined with respect to each ultimate target speed of the carriage and each moving direction, and contained in a table. Three kinds of tables, i.e. a table for heavy load, a table for light load and a table for standard load in accordance with the difference in load applied to individual drive systems of the carriage, as well as one kind of table for low temperature are prepared and stored on a ROM. It is determined which of the three kinds of tables should be selected at normal temperature by actually driving the carriage in the final step of the manufacturing process.

Abstract: The invention provides a method for controlling an electromechanical servomechanism (20) for moving an output member relative to a variable load (38). The servomechanism includes: a motor (37) having at least one coil (32A, 32B or 32C) adapted to be supplied with current and having a rotor (33) with an output shaft (35); a mechanical transmission (36) arranged between the output shaft and the load, the transmission having a mechanical friction related to the load; a servoamplifier (30) arranged to supply current to the motor coil in response to an input signal (in line 29); a command signal (in line 21) for commanding the position of the load; a load position feedback signal (in line 23) compared (in summing point 22) to the command signal and arranged to produce an error signal (in line 24); and means (28) for generating an offset signal (in line 26) that is summed (in summing point 25) with the error signal to modify the servoamplifier input signal (in line 29).

Abstract: The regenerative braking method and system for an electric vehicle in which regeneration current is calculated and controlled using control of an air conditioning system to consume a portion or all of the surplus regeneration power, thereby enhancing braking performance and feel. Control includes calculation of a regeneration current and comparison of the regeneration current to battery current to calculate the surplus regeneration power.

Abstract: A method for detecting a state of an electric motor includes: energizing the motor with electrical power such that an associated current applied to the electric motor rises over time toward a reference level; determining an amount of time that elapses between when the motor is energized and the reference level is reached; and, evaluating a state of the motor based upon the determined amount of time.

Abstract: A controller is provided for transitioning a drive signal to a single phase motor between a square wave and pulse width modulation modes, wherein the drive signal is in square wave mode at low motor frequencies and in pulse width modulation mode during normal operation. The transitioning includes using a real time motor model to effectuate transition of the drive signal between the modes, and a sampling rate for sampling the real time motor model during the transitioning. The sampling rate is automatically modified during the transitioning, wherein acceleration of the motor includes transitioning the drive signal from square wave mode to pulse width modulation mode, including periodically increasing the sampling rate during the transitioning. Conversely, when transitioning from pulse width modulation mode to square wave mode, the controller automatically deaccelerates the sampling rate during the transitioning.

Abstract: A control system for an electric machine having a rotor position sensor that generates a rotor position signal, a velocity module that generates an electric angular velocity value based on the rotor position signal, a random pulse width modulation module that generates a switching period and a delay for a current cycle, and a phase angle compensation module that sums a sample rate, one half of the switching period, and the delay of a previous cycle and that outputs a delay time. The phase angle compensation module further multiplies the delay time and the electric angular velocity value and generates a compensating angle.

Abstract: In a synchronous motor control device that corrects a deviation in rotational position which is related to a rotational position detector for a synchronous motor on which vector-control is performed, the synchronous motor control device includes: a current instruction generator that disables a torque instruction to set d-axis and q-axis current instructions as zero when a phase correction instruction is inputted; a current controller that outputs d-axis and q-axis voltage instructions based on the d-axis and q-axis current instructions; a phase correction quantity detector for determining the amount of offset in which the d-axis voltage instruction becomes zero when the phase correction instruction is inputted and the d-axis voltage instruction is not zero; an adder for adding a rotor positional angle and the amount of offset; and a voltage converter for determining three-phase voltage instructions based on the additional value, the d-axis and q-axis voltage instructions.