Hitachi, Ltd.

Hitachi Industrial Equipment Systems Co., Ltd.

Kouki Yamamoto

Miyoshi Takahashi

Satoshi Kikuchi

Haruo Koharagi

Masaharu Senoh

Kazuo Sato

Kim Houng Joong

Keiji Noma

Kohei Ishii

Hiroyuki Tomita

Yoshitaka Iwaji

Toshiaki Okuyama

Haruo Miura

Yasuo Fukushima

Koichiro Nagata

Tsukasa Taniguchi

Takashi Okada

Kenji Miyata

Kazuo Tahara

Hiromi Inaba

Kohji Maki

Tadashi Fukushima

Ryoichi Takahata

Ikuo Yamato

Daigo Kaneko

Hideki Ayano

Tsunehiro Endou

Provided is a drive device for an alternating current motor which performs vector control on sensorless driving of the alternating current motor in an extremely low speed region without applying a harmonic voltage intentionally while maintaining an ideal PWM waveform. A current and a current change rate of the alternating current motor are detected, and a magnetic flux position inside of the alternating current motor is estimated and calculated in consideration of an output voltage of an inverter which causes this current change. The current change rate is generated on the basis of a pulse waveform of the inverter, and hence the magnetic flux position inside of the alternating current motor can be estimated and calculated without applying a harmonic wave intentionally.

Drive device for alternating current motor and electric motor vehicle

The present invention provides an induction motor controller which includes: a circuit for generating a d-axis current reference signal from a d-axis current command value and a periodically varying periodic signal; a d-axis current controller for controlling a d-axis motor current flowing through an induction motor to be controlled to match the d-axis current reference signal; parameter determining means for calculating and determining a motor parameter of the induction motor based on a deviation of the d-axis motor current from the d-axis current reference signal, and controlling a voltage applied to the induction motor using a compensation voltage calculated from the calculated and determined motor parameter, in which a control parameter for controlling the induction motor is set based on the calculated and determined motor parameter.

Induction motor controller

An object of the present invention is to provide a driver for an induction motor which performs an operation at an acceleration suitable for the magnitude of a load and is excellent in efficiency, without an acceleration failure. The driver for an induction motor includes a slip frequency estimate value arithmetic operation sectionfor arithmetically operating a slip frequency &#x3c9;s^ of an induction motorand a maximum torque generation slip arithmetic operation sectionfor arithmetically operating a slip frequency &#x3c9;smax at which a maximum torque is generated. When the slip frequency &#x3c9;s^ exceeds a predetermined value &#x3c9;smaxTH (=0.9 &#x3c9;smax, etc.) corresponding to the slip frequency &#x3c9;smax at which the maximum torque is generated, a speed change rate arithmetic operation sectionand a speed change rate correcting sectionreduce a rate of increase in a speed command &#x3c9;r*. In addition, when the slip frequency approaches the maximum torque generation slip frequency too closely, the load concerned is judged to be overloaded, and an alarm is generated.

Driver for induction motor and method of driving the same

An air conditioner comprising a compressor including a compression unit and a permanent magnet rotating electric machine, wherein the permanent magnet rotating electric machine includes a stator, into which concentratively wound armature windings are inserted in such a way as to surround a plurality of teeth formed in a stator core, and a rotor having permanent magnets accommodated into a plurality of permanent magnet inserting holes formed in a rotor core. Each pair of adjacent ones of said permanent magnets is arranged generally in one of a convex V-shaped configuration and a convex U-shaped configuration with respect to a rotor axis, and a substantially V-shaped recess portion is formed between adjacent poles in outer circumferential surface portions of the rotor core.

Air conditioner having permanent magnet rotating electric machine

A door system includes a door support by which a door is movably supported, a linear motor for generating a thrust to open and close the door, a link mechanism made of a non-magnetic material for transmitting the thrust generated by the linear motor to the door. The linear motor an armature, and a part having magnetism. The armature includes a first magnetic pole having a first polarity and a second magnetic pole having a second polarity. The first magnetic pole and the second magnetic pole collectively include a first opposed part which defines a first gap, and a second opposed part which defines a second gap. The part having magnetism is disposed in the first gap and the second gap. The door system may be used in the car of an elevator system.

Door system including linear motor driving mechanism

There is provided a linear motor, having an armature and a needle with magnetism, in which the armature has at least a magnetic pole of a first polarity having a first opposed part and another magnetic pole of a second polarity having a second opposed part; the needle is held by the first opposed part, and is further held by the second opposed part; and a distribution of magnetism of the needle according to a position in the movable direction thereof. In this way, a leak of a magnetic flux from pole teeth passing between the pole teeth of the armature is decreased to increase a thrust and braking force of the needle, which is thereby enabled to generate a greater or smaller thrust in a specific section or sections than the thrust during usual linear movement.

Linear motor

A permanent magnet rotating electric machine that comprises a stator, into which concentratively wound armature windings are inserted in such a way as to surround a plurality of teeth formed in a stator core, and a rotor having permanent magnets accommodated into a plurality of permanent magnet inserting holes formed in a rotor core. In this rotating electric machine, the permanent magnets are convex V-shaped or U-shaped with respect to a rotor axis. Moreover, nearly V-shaped recess portions, each of which is placed between adjacent poles, are formed in outer circumferential surface portions of the rotor core. Thus, torque caused by magnetic flux due to the magnets is increased, while armature reaction magnetic flux generated by an armature current is reduced. Consequently, q-axis inductance is reduced, so that armature current commutation is quickly achieved. Thus, the permanent magnet rotating electric machine using the stator employing concentrated windings and also using the magnet-embedded rotor is stably driven even when driven by a position sensorless inverter in the case of 120 degree energization.

Permanent magnet rotating electric machine

There is provided a vehicle operating system constituted of a vehicle and at least a charging apparatus, the system comprising means for enabling high-precision unmanned positioning, despite primarily vertical displacements of the vehicle due to changes in tire pressure or weight of a passenger or passengers, and hence enabling efficient, stable power feeding. The charging apparatus includes a power feeding unit, and a vehicle includes a power receiving unit for feeding power in a noncontact manner, which makes possible recharging without manual assistance. A C-shaped transformer and an I-shaped transformer are used for the power feeding unit and the power receiving unit, respectively, so that a magnetic flux induced therebetween can develop substantially in the horizontal direction, thereby feeding power stably despite changes in tire pressure and the like. Tire guides for guiding the vehicle to a power feeding position and a car stop are so used that when the vehicle comes in contact with the car stop, the power feeding unit and the power receiving unit will face each other in a correct position, thus enabling high-precision positioning at power feeding time.

Vehicle operating system

A door system, which uses a linear motor, has a door hanger from which a door is movably suspended, an electric motor for generating a thrust to open and close the door, and a link mechanism made of a non-magnetic material for transmitting the thrust generated by the motor to the door. The linear motor has an armature to serve as a mover runner and a stator having magnetism. The armature has at least a magnetic pole of a first polarity having a first opposed part and another magnetic pole of a second polarity having a second opposed part. The stator is held by the second opposed part.

The present invention provides a permanent magnet rotating electric machine that comprises a stator, into which concentrated wound armature windings are inserted in such a way as to surround a plurality of teeth formed in a stator core, and a rotor having rare earth permanent magnets inserted into a plurality of permanent magnet holes, which are formed in a rotor core and used for accommodating permanent magnets. In this permanent magnet rotating electric machine, the permanent magnets are each shaped like a convex &ldquo;V&rdquo; or &ldquo;U&rdquo; with respect to the shaft of the rotor. Moreover, a ratio of the width W of an interpole core between the permanent magnets to the width Xg of the gap between the stator core and the rotor core is set in such a manner as to satisfy the following condition: 0.8&lE;W /Xg&lE;13.2. Thus, even when this rotating electric machine is driven by a position sensorless inverter in the case of 120 degree energization, the system efficiency is enhanced.

A very high speed permanent magnet type electric rotating machine, in which loss generated on a rotor is small to achieve high efficiency on an air generating source even when driven by an inverter operating at a fundamental frequency of at least several hundreds of Hz and in which a reactor is inserted between the inverter and a permanent magnet type synchronous motor, and content percentages of components of harmonic current supplied to the permanent magnet type synchronous motor are adjusted such that when a content percentage of a fundamental wave is 100%, a content percentage B of a seventh order component is at most 10% and a total content percentage is made equal to or less than a certain value so as to satisfy the relationship (A<C<B) where A is a content percentage of a fifth order component, B is a content percentage of a seventh order component thereof, and C is a content percentage of a ninth order component thereof, thereby enabling realizing a very high speed permanent magnet type electric rotating machine system, in which harmonic loss of neodymium magnets as well as harmonic loss of a shaft is greatly reduced and loss of the rotor can be reduced to several hundreds of W.

Very high permanent magnet type electric rotating machine system

Provided are a super-high speed permanent magnet type synchronous motor which causes less loss in a rotor even though it is driven by an inverter adapted to be operated with a fundamental frequency around 1 kHz, and an air compressor. The air compressor having a super-high speed permanent magnet type synchronous motor which is composed of a stator in which armature windings are wound in a plurality of slots formed in a stator core, and a rotor including a shaft made of a conductive magnetic material, a conductive permanent magnet laid around the outer periphery of the shaft, and a reinforcing member made of carbon fibers and laid around the outer periphery of the permanent magnet, wherein a laminated electromagnetic steel sheet is interposed between the shaft and the permanent magnet, and the laminated electromagnetic steel sheet has a high tensile strength higher than 70 kg/mm .

Growing community of inventors

Hitachinaka, Japan

Kouki Yamamoto