Fanuc Corporation

Takashi Harada

Shinichi Horikoshi

Yasusuke Iwashita

Masakazu Niwa

Koujirou Sakai

Masatomo Shirouzu

Tomokazu Yoshida

Mitsuyuki Taniguchi

Naoto Ota

Keisuke Imai

Yuuichi Yamada

Wataru Kuroki

Shinichi Mizukami

Mamoru Yaeshima

Ichirou Nagatomo

Eiichi Sasuga

The power conversion device includes an AC power source, a power conversion unit, and an LC filter unit arranged between the AC power source and the power conversion unit, and the LC filter unit has a temperature detection element provided in one part or in a plurality of parts configuring the LC filter unit, and the power conversion unit has a temperature detection unit configured to receive temperature data detected by the temperature detection element and a determination unit configured to calculate temperature rise values of one or plurality of parts, or temperature differences between the plurality of parts based on the temperature data received by the temperature detection unit and to determine whether or not there is an abnormality in the LC filter unit in accordance with the calculation result.

Power conversion device including abnormality detection function of LC filter

A motor driving apparatus capable of detecting during operation a ground fault and a phase-to-phase short circuit by distinguishing one from the other is provided while minimizing an increase in cost. The sum of three-phase AC currents supplied from a three-phase AC power supply to an AC/DC converter is detected by a current sensor. When overcurrent is detected by an overcurrent detector, if the sum of the currents detected by the current sensor is zero, it is determined that the fault is a phase-to-phase short circuit, but if the sum is not zero, it is determined that the fault is a ground fault.

Motor driving apparatus having fault diagnostic function

A motor driving apparatus is provided that performs AC/DC conversion by suppressing harmonics of the input at the time of normal operation, while on the other hand, allowing system operation to continue in the event of an overload by avoiding system stoppage. The motor driving apparatus, which drives a motor by supplying power from an AC power supply, includes: an AC/DC converter having a converter operation mode which is switched between a PWM converter operation mode in which an AC input voltage is converted into a DC voltage by applying PWM control to a plurality of power switching devices connected in serial and parallel fashion and a diode rectifier operation mode in which an AC input voltage is converted into a DC voltage by using a plurality of diodes each connected in reverse parallel with an associated one of the plurality of power switching devices; and a converter control unit which dynamically switches the converter operation mode of the AC/DC converter according to a load during powering of the motor.

Motor driving apparatus having function of dynamically switching converter operation mode of AC/DC converter

When the output of motor reaches or exceeds a predetermined value during acceleration of the motor, the control target value of the DC link voltage which is the voltage of a power storage device is gradually lowered in corresponding relationship to the motor output. When the motor enters a constant speed control mode, the DC link control target value is maintained at a constant level. When the motor enters a deceleration control mode, the DC link control target value is gradually raised in corresponding relationship to the motor output, and regenerative power is recovered by the power storage device and reused in the next control cycle.

Motor driving apparatus

During motor acceleration control period that starts at time T, if power supply output or supply current exceeds a predetermined level at time T, PWM control in a PWM converter is turned off until a deceleration control period of Tto Tends. As a result, DC link voltage (voltage of a power storage device) at the start of the deceleration control at time Tdrops to provide space for storing regenerative power; since the PWM control in the PWM converter is off during the deceleration control period, the regenerative power can be stored into the power storage device and reused in the next control cycle.

A motor driving apparatus comprises: an AC/DC converter which converts AC voltage supplied from an AC power source into DC voltage through PWM switching control of a power switching device; and a DC/AC converter which converts the DC voltage into variable-frequency AC voltage for driving a motor in a controlled manner. The AC/DC converter includes: a control unit which generates, based on an error between the DC voltage and a DC voltage command value, a PWM signal for the PWM switching control of the power switching device; and a frequency/gain varying unit which sets the frequency of the PWM signal to be generated by the control unit and a control gain in the control unit higher than their normal levels during a period in which a load in the DC/AC converter varies.

Motor driving apparatus having DC link voltage regulating function

A motor drive device including a converter for a power running operation and a power regenerative operation. The converter has power switching elements, a first power regenerative control unit for controlling the power switching elements in the power regenerative operation by using pulse width modulation signal whose pulse width changes with a value indicated by a command signal; a second power regenerative control unit for controlling the power switching elements in the power regenerative operation to generate respective power regenerative currents in a phase representing the maximum potential among three phases of a three-phase AC power supply and a phase representing the minimum potential among the three phases, and a power regenerative operation switching unit for switching a control of the power switching elements in the power regenerative operation between a control by the first power regenerative control unit and a control by the second power regenerative control unit.

Motor drive device with function of switching to power regenerative operation mode

While the motor drive amplifier is not operating, electromagnetic switch contacts are held closed for a predetermined period of time, three-phase power is rectified by a rectifier circuit and a smoothing capacitor is charged. Then, the smoothing capacitor is discharged through a discharging resistor and, when a predetermined voltage is reached, a contact is closed, with the result that a closed circuit is formed by the smoothing capacitor, a detection resistor, a motor coil, motor insulation resistance, and ground. A voltage generating across the detection resistor due to leakage current is detected and compared with a reference value. If the detected voltage exceeds the reference value, an insulation degradation signal is delivered.

Motor driver

In a control apparatus, a 'characteristic value calculation' block calculates a characteristic value (such as amplitude value, offset value, or waveform distortion for each phase of two-phase sinusoidal signals optically input from an encoder, or phase difference between the two phase signals) for each of the two-phase sinusoidal signals, and an 'alarm detection' block checks the presence or absence of an excursion outside a predetermined allowable range and, if such an excursion is detected, produces an alarm indication or the like. Each time the &#x201c;present characteristic value&#x201d; is input, a &#x201c;characteristic value comparison&#x201d; block compares it with &#x201c;previous characteristic values&#x201d;, and analyzes the result of the comparison. That is, the difference between the present value and each previous data is calculated, and the largest amount of variation (with plus or minus sign) is obtained; if this amount is larger than a predetermined value, a signal indicating an &#x201c;imminent failure&#x201d; is output. In an alternative method, the present value is compared with a characteristic value calculated from an encoder reference signal. Further, the characteristic value monitoring and comparison may be performed within the encoder. In this way, data useful for the prediction of encoder failure, etc. is provided.

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Minamitsuru-gun, Japan

Takashi Harada