Hitachi Industrial Equipment Systems Co., Ltd.

Hitachi, Ltd.

Sega Enterprises, Ltd.

Atsuhiko Nakamura

Yusaku Onuma

Hiroshi Watanabe

Yoshitaka Iwaji

Kazuaki Tobari

Takuya Sugimoto

Agnes Hadinata

Seiji Ishida

Yoshiyuki Taguchi

Hiroshi Fujii

Hiroyuki Tomita

Kohji Maki

Satoshi Ibori

Masahiro Hiraga

Hironori Ohashi

Yusuke Arao

Takatsugu Kambara

Kazushige Hotta

Masataka Sasaki

Hironori Oohashi

This power conversion device has: a current measurement unit for measuring phase current; a current vector calculation unit for calculating a current vector by performing 3-phase to 2-phase conversion on the phase current; an amount-to-be-analyzed calculation unit for calculating, on the basis of the current vector, an amount to be analyzed; and a feature amount waveform extraction unit for extracting a waveform in a specific frequency range on the basis of the amount to be analyzed.

Power conversion device, rotating machine system, and diagnosis method

The purpose of the present invention is to provide a speed detection method for maintaining a fine time axis resolution and a power conversion device that uses the method. This power conversion device comprises an inverter for converting DC voltage into AC voltage and supplying the same to a motor, a motor speed calculation unit for calculating the speed of the motor from output pulses obtained from an encoder connected to the motor, and a control unit for receiving the motor speed from the motor speed calculation unit and controlling the inverter. In the power conversion device, the motor speed calculation unit measures the duty cycle of the output pulses, calculates the speed using the half cycles of the output pulses if the duty cycle is within a prescribed range from 50%, and calculates the speed using the full cycles of the output pulses if the duty ratio is outside of the prescribed range from 50%.

Speed calculation device and power conversion device

This power conversion device comprises: a power converter including a switching element; and a control unit which controls the power converter. The control unit calculates a torque electric current detection value and an excitation electric current detection value from an electric current flowing to an external device, and when an absolute value of the torque electric current detection value is greater than or equal to the excitation electric current detection value, performs control such that the excitation electric current detection value follows the torque electric current detection value.

Power conversion device

A power conversion device includes a harmonic voltage generation unit that superimposes dc-axis and qc-axis harmonic voltages on dc-axis and qc-axis voltage commands in accordance with a switching signal; and an inductance estimation unit that estimates dc-axis inductance and qc-axis inductance on a basis of dc-axis and qc-axis harmonic currents, amplitude values of the harmonic voltages, and the switching signal.

A power conversion apparatus controls a load apparatus by position sensorless vector control. The power conversion apparatus includes: a current detection unit configured to detect a current passing through the load apparatus; a current detection arithmetic unit configured to calculate a harmonic current component on a dc-axis as a control axis and a harmonic current component on a qc-axis, based on the detected current; a saliency ratio estimation unit configured to output a saliency ratio estimated value based on the harmonic current component on the dc-axis and the harmonic current component on the qc-axis; and a saliency ratio control unit configured to output a current component that increases or decreases a current command value on a d-axis of a rotor coordinate system, based on a deviation between the saliency ratio estimated value and a predetermined saliency ratio.

Power conversion apparatus

A pulse width modulation method has the steps of operating a second instruction signal so that each of the differences between two or three arbitrary instruction signals in three first instruction signals may become more than the predetermined value, and modulating in pulse width based on the second instruction signal.

Pulse width modulation method for a power converter

The present invention relates to a virtual course display method of displaying on display means a virtual course, which is constructed by connecting a plurality of virtual course parts and where a virtual mobile body runs, the method comprising the steps of: randomly selecting a predetermined number of successively connectable virtual course parts data from among plural pieces of virtual course parts data having different shapes and each being connectable to at least one of other virtual course parts data; storing at least a connecting order of the selected predetermined number of virtual course parts data; constructing a virtual course including virtual course parts data a mobile body passes and a predetermined number of virtual course parts data following the former virtual course parts data based on the connecting order; generating an image of the virtual course; and displaying the image of the virtual course on the display means. The present invention also relates to a game machine and storage medium for the above method.

Virtual course display method and game machine using the same

The present invention relates to a method, apparatus and computer readable medium for a race game. The method comprising the steps of: computing positions of first and second mobile bodies on a course defined within a predetermined coordinate space every predetermined sampling time; detecting whether the first or second mobile body, whichever is leading, passes a predetermined point on the course from computed positional information of the first and second mobile bodies on the course; detecting whether the following mobile body does not pass the predetermined point within a predetermined set time after the leading mobile body has passed the predetermined point, from the computed positional information; and indicating game over on a display when it is detected that the following mobile body does not pass the predetermined point within the set time. Also, the method relates to measure whether the distance between mobile modies exceeds a set value or not.

Method and apparatus for measuring virtual time difference or virtual

In a motor speed controller for controlling an AC motor to be driven at a variable speed, a signal proportional to a load torque and a signal proportional to an output torque of the AC motor are found by current detecting means for detecting the primary current of the AC motor, and integrated over the speed changing period, and the integrated values are divided by the values corresponding to the amounts of speed change during the speed changing period so that the moment of inertia can be computed. In addition, there is provided means for changing the rate of output frequency change caused by the output frequency command into a value according to the calculated moment of inertia. Moreover, there is provided a circuit for detecting a sudden change of the calculated moment of inertia, so that when a sudden change occurs, an abnormality signal is generated.

Growing community of inventors

Tokyo, Japan

Atsuhiko Nakamura