Abstract: The invention provides a synchronous motor sensorless controller which drives a synchronous motor without use of a rotational position sensor. The controller has a relative position counter 4 which acquires an estimated position of a magnetic pole from the position-and-speed estimation device simultaneously with resetting a summated value to zero when the reference position signal is input and which starts summation operation; and a speed instruction generator 3 having a position controller 29 which performs position control operation on the basis of a deviation between an instruction value pertaining to the amount of movement from the reference position and a summated value output as a relative position from the relative position counter, the generator outputting a speed instruction. The sensorless controller can position at a predetermined location a synchronous motor not having a position sensor.

Abstract: A control apparatus includes a current detector which detects a current of a synchronous motor, a coordinate converter which coordinate-converts the current obtained from the current detector into a current on rotational biaxial coordinates (d-q axis) rotated at an angular frequency w, a current controller which outputs a voltage command on the rotational biaxial coordinates (d-q axis) such that a current on the rotational biaxial coordinates (d-q axis) follows a current command on the rotational biaxial coordinates (d-q axis), a coordinate converter which coordinate-converts the voltage command on the rotational biaxial coordinates (d-q axis) obtained from the current controller into three-phase voltage commands, an adaptive observer which calculates the angular frequency w, an estimated current of the synchronous motor, an estimated rotor magnetic flux, and an estimated rotational speed based on the current on the rotational biaxial coordinates (d-q axis) and the voltage command on the rotational biaxial co

Abstract: A magnetic-pole position detecting apparatus for a synchronous motor includes an arithmetic section outputting six voltage vectors having equal amplitudes and equal-interval phases to a circuit section as a voltage vector command. The circuit section applies the voltage vectors to a synchronous motor, outputs a trigger signal to a detection section each time after finishing the application of each voltage vector, and detects each phase. Thereafter, the arithmetic section calculates and outputs magnetic-pole positions at every 60/(2k) degrees (where k is a natural number based on the detection current. Each voltage vector is applied for a time period sufficient for each phase winding to be magnetically saturated in an order so that the phases of each voltage vector either increase monotonically or decrease monotonically.

Abstract: In the synchronous motor controlling apparatus and method of the invention, a current is detected and subjected to coordinate transformation onto &ggr;-&dgr; axis assumed for the rotor. A correction term is obtained on the basis of the derived current and an arbitrarily given correction current instruction. A &ggr;-&dgr; axis voltage instruction is computed by adding a value obtained by multiplying the correction term by a proper gain to a voltage equation in a steady state of the synchronous motor. Consequently, a control method of small computational load, which does not require gain adjustment according to the inertia of a motor load, can be attained.

Abstract: A motor operation controller, which can accommodate different power supply voltages by changing a minimum circuit configuration using common motors, wiring, etc., has an insulation structure between input power supply and the motors for providing the capability of bidirectional operation in a power mode and a regeneration mode. The motor operation controller comprises a converter section and an inverter section for supplying power to a motor. In the converter section, there is an insulation type bidirectional DC voltage conversion function provided by an insulation type bidirectional DC voltage conversion section 32 having an insulation type bidirectional DC voltage converter 33, a controller 35, and a smoothing circuit 34.

Abstract: A conventional synchronous motor controlling method estimates the speed and performs a vector control, so that the gain of a speed control system has to be adjusted according to the inertia of a load connected to the motor shaft, and computation is also relatively complicated.

Abstract: The invention relates to a magnetic-pole position detecting apparatus for a synchronous motor. An arithmetic section outputs six kinds of voltage vectors having equal amplitudes and equal-interval phases to a circuit section as a voltage vector command. The circuit section makes the voltage vectors to be applied to a synchronous motor, outputs a trigger signal to a detection section each time after finishing the application of each voltage vector, and makes a detection current of each phase to be detected. Thereafter, the arithmetic section calculates and outputs magnetic-pole positions at every 60/(2{circumflex over ()}k) degrees (where k is a natural number) based on the detection current. Each voltage vector is applied for a time period sufficient enough for each phase winding to be magnetically saturated in the order that the phases of each voltage vector either increase monotonously or decrease monotonously.

Abstract: There is provided a controlling device for an AC motor having a structure in which a current of a three phase brushless DC motor is detected and then converted to a rotor coordinate system, to separately control a torque split current (q axis) and an exciting split current (d axis), wherein an offset is estimated with a DC component of a multiplied value of the values corresponding to a d axis voltage command which is an output of an exciting split current controller and an electrical angle, and the detected current is compensated for, so that an offset of a current detector may be estimated and compensated for during its operation without stopping its rotation and the motor can rotate smoothly without a torque ripple, even in the case in which the current detector has an offset error or in the case in which an offset changes due to a temperature drift.

Abstract: The invention is an induction motor controller for measuring electrical constants of a polyphase induction motor (102) by supplying test power thereto and controlling driving of the polyphase induction motor with a polyphase inverter (105) by using parameters for controlling driving of a result of the measurement.

Abstract: An electrical discharge machining power supply circuit for machining a workpiece, including: a power supply circuit; a first circuit including a first switching device and a first rectifying device; a second circuit including a second switching device and a second rectifying device; an electrical discharge machining electrode for providing an electrical discharge to the workpiece; and a first circuit device for preventing an excessive current generated by wiring inductance in the circuit from damaging at least the first switching device.