Abstract: The present invention achieves highly accurate control characteristics by estimating an induced voltage coefficient of a magnet motor without rotary auto-tuning. A first power Pc is calculated on the basis of the output voltage and output current of the magnet motor, and a second power Pc{circumflex over (?)} is calculated on the basis of the electric circuit constant, current command, output frequency, and induced voltage coefficient of the magnet motor. The induced voltage coefficient is estimated so that the calculated first power follows the second power, and the driving of the magnet motor is controlled in accordance with the induced voltage coefficient.

Abstract: A rotation control method of a synchronous motor, the motor comprising: a stator having AC windings thereround; and a rotor, being mounted within said stator, rotatably, wherein on an each surface, opposing to the rotor, of poles building up the stator, are formed plural numbers of teeth portions, and on a surface of the rotor, being made of permanent magnet, opposing to the poles of the stator, are also formed plural numbers of teeth portions, with a width being nearly equal to that of the teeth portion in a circumference direction thereof, and further AC voltages having a predetermined voltage-frequency characteristic is supplied to AC windings wound around the poles of the stator, and the AC voltages supplied from the inverter is so determined in the voltage-frequency characteristic thereof, at least within a part of frequency band equal or less than a predetermined rated frequency, a pull-out torque of the synchronous motor is equal to or greater that a rated pull-out torque at the predetermined rated fre

Abstract: A rotation control method of a synchronous motor, the motor comprising: a stator having AC windings thereround; and a rotor, being mounted within said stator, rotatably, wherein on an each surface, opposing to the rotor, of poles building up the stator, are formed plural numbers of teeth portions, and on a surface of the rotor, being made of permanent magnet, opposing to the poles of the stator, are also formed plural numbers of teeth portions, with a width being nearly equal to that of the teeth portion in a circumference direction thereof, and further AC voltages having a predetermined voltage-frequency characteristic is supplied to AC windings wound around the poles of the stator, and the AC voltages supplied from the inverter is so determined in the voltage-frequency characteristic thereof, at least within a part of frequency band equal or less than a predetermined rated frequency, a pull-out torque of the synchronous motor is equal to or greater that a rated pull-out torque at the predetermined rated fre

Abstract: An inverter device and a motor driving device are arranged to have an inrush current prevention circuit for preventing an inrush current from flowing into a smoothing circuit when the power is turned on. The inrush current prevention circuit includes a current limiter for limiting the inrush current, a plurality of semiconductor switching elements, and an inrush current prevention circuit driving -circuit for driving the plurality of semiconductor switching elements, the semiconductor switching elements being connected together.

Abstract: An inverter device and a motor driving device are arranged to have a rush preventing circuit for preventing rush current from being flown in a smoothing circuit when the power is turned on. The rush preventing circuit includes a current-limiting means for limiting rush current, a plurality of semiconductor switching elements, a rush preventing circuit driving circuit for driving these semiconductor switching elements, and those semiconductor switching elements being connected in parallel to each other.

Abstract: An inverter device and a motor driving device are arranged to have an inrush current prevention circuit for preventing an inrush current from flowing into a smoothing circuit when the power is turned on. The inrush current prevention circuit includes a current limiter for limiting the inrush current, a plurality of semiconductor switching elements, and an inrush current prevention circuit driving—circuit for driving the plurality of semiconductor switching elements, the semiconductor switching elements being connected together.

Abstract: An inverter apparatus operatable over an extended output frequency range having an increased upper limit with error contained in the output voltage being suppressed by eliminating dispersions of PWM pulse signals. A PWM command pulse signal and an output voltage detection signal derived from the output of the inverter are compared straightforwardly with each other for determining difference therebetween on the basis of which error contained in the inverter output voltage is canceled. An isolation device for isolating electrically a low-voltage-rated control circuitry and a high-voltage-rated main circuitry from each other is inserted between a PWM command pulse signal generating circuit and a pulse width correcting circuit.

Abstract: An inverter apparatus having at least an inverting portion for inverting a DC electric power into an AC electric power, wherein the inverting portion includes: high speed switching elements; driver circuits for driving the high speed switching element; and a controller portion for outputting logical driving ON/OFF signals for controlling the AC electric power to the driver circuit, wherein the controller portion controls so that the minimal time of the OFF signal of the logical driving ON/OFF signals for the high speed switching element comes to be equal or greater than a predetermined value, thereby protecting the high speed switching elements constructing the inverter apparatus from breakdown due to a the short OFF pulse.

Abstract: A signal whose frequency is proportional to a rotational speed of a rotor and whose rising and falling angles near points crossing zero becomes larger with the rotational speed of the rotor is used to produce a first signal of amplitude corresponding to the rising and falling angles and a second signal of amplitude corresponding to the frequency, a difference between the first and second signals is evaluated, and the first or second signals are corrected with the difference.