Abstract: An active filter device includes a power module configured to generate a compensating current to suppress a harmonic current generated from a load device and a controller configured to control the power module. The controller includes a current command calculation unit configured to calculate a compensating current command to suppress the harmonic current, a control variable calculation unit configured to calculate a control variable based on a deviation between the compensating current command and an actual compensating current, a duty cycle calculation unit configured to calculate duty cycle of each of three phases based on the control variable, a duty cycle modulation unit configured to perform two-phase modulation on the duty cycle of each of three phases, and a control signal generation unit configured to, after the two-phase modulation, generate, from the duty cycle of each of three phases, a control signal to drive the power module.

Abstract: An active filter device includes a power module configured to generate a compensating current to suppress a harmonic current generated from a load device and a controller configured to control the power module. The controller includes a current command calculation unit configured to calculate a compensating current command to suppress the harmonic current, a control variable calculation unit configured to calculate a control variable based on a deviation between the compensating current command and an actual compensating current, a duty cycle calculation unit configured to calculate duty cycle of each of three phases based on the control variable, a duty cycle modulation unit configured to perform two-phase modulation on the duty cycle of each of three phases, and a control signal generation unit configured to, after the two-phase modulation, generate, from the duty cycle of each of three phases, a control signal to drive the power module.

Abstract: A printed circuit board assembly includes a first printed circuit board with first surface and second surface with a slit portion and a second printed circuit board with third surface and fourth surface with a first end portion and a second end portion. The first end portion is fitted in the slit portion and a tip of the first end portion protrudes from the second surface. The first printed circuit board includes first electrodes arranged along the slit portion in a longitudinal direction of the slit portion on the second surface. The second printed circuit board includes second electrodes arranged in the first end portion on the third and fourth surfaces. The second electrodes are joined to the first electrodes with solder. The first printed circuit board includes a support fixed to the first surface. The second printed circuit board is attached to the support by an adhesive substance.

Abstract: A motor drive apparatus includes a power converter including an inverter having an upper arm and a lower arm, the inverter being configured to control an operation of an electric motor, and a drive controller configured to apply a dead time for preventing a short circuit between the upper arm and the lower arm, and to control the power converter. The drive controller is configured to control the power converter by switching a first mode in which a first correction value representing a time used to correct a voltage drop due to the dead time is employed to control the power converter, and a second mode in which a second correction value smaller than the first correction value is employed to control the power converter.

Abstract: A printed circuit board assembly includes a first printed circuit board having a first surface and a second surface that is opposite the first surface and including a slit portion and a second printed circuit board having a third surface and a fourth surface that is opposite the third surface and including a first end portion and a second end portion that is opposite the first end portion. The first end portion is fitted in the slit portion in such a manner that a tip of the first end portion protrudes from the second surface. The first printed circuit board includes a plurality of first electrodes arranged along the slit portion in a longitudinal direction of the slit portion on the second surface. The second printed circuit board includes a plurality of second electrodes arranged in the first end portion on the third surface and the fourth surface, and the plurality of second electrodes are joined to the plurality of first electrodes with solder.

Abstract: A motor drive apparatus includes a power converter including an inverter having an upper arm and a lower arm, the inverter being configured to control an operation of an electric motor, and a drive controller configured to apply a dead time for preventing a short circuit between the upper arm and the lower arm, and to control the power converter. The drive controller is configured to control the power converter by switching a first mode in which a first correction value representing a time used to correct a voltage drop due to the dead time is employed to control the power converter, and a second mode in which a second correction value smaller than the first correction value is employed to control the power converter.

Abstract: An electric motor drive device including a drive controller configured to control an operation of an inverter, the drive controller including a frequency setting unit configured to set an operating frequency of an electric motor, a frequency determining unit configured to determine whether or not the operating frequency set in the frequency setting unit is equal to or lower than a set frequency threshold value, a voltage determining unit configured to determine whether or not a value of a DC voltage is equal to or larger than a set voltage threshold value, and an inverter controller configured to control the inverter based on the operating frequency set in the frequency setting unit.

Abstract: An electric motor drive device including a drive controller configured to control an operation of an inverter, the drive controller including a frequency setting unit configured to set an operating frequency of an electric motor, a frequency determining unit configured to determine whether or not the operating frequency set in the frequency setting unit is equal to or lower than a set frequency threshold value, a voltage determining unit configured to determine whether or not a value of a DC voltage is equal to or larger than a set voltage threshold value, and an inverter controller configured to control the inverter based on the operating frequency set in the frequency setting unit.