Daikin Industries, Ltd.

Sumitomo Electric Industries, Limited

Nobuki Kitano

Naoto Kobayashi

Hiroshi Hibino

Minoru Kitou

Takeshi Araki

Michihiro Nakagawa

Hirohito Maeda

Keisuke Shimatani

Masaki Kouno

Masakazu Katou

Ryou Matsuyama

Ryuuji Yasumoto

Tatsuki Inoue

Takeshi Ashida

Takeomi Ukai

Hironobu Mizobe

Ashida Takeshi

Masaki Kuono

A power converter converts a DC voltage including a pulsation component into an AC voltage and outputs the AC voltage to a synchronous electrical motor. A control device for controlling the power converter includes a pulsation component detection unit and a control circuit. The pulsation component detection unit detects a pulsation component. The control circuit controls the power converter so that a load angle of the synchronous electrical motor is increased in accordance with increase in an instantaneous value of the pulsation component.

Control device for power converter

An inverter device includes a converter section, an inverter section, and a control device. The converter section full-wave rectifies a three-phase AC voltage and outputs a DC voltage including a ripple component having a frequency six times the frequency of the three-phase AC voltage. The inverter section converts the DC voltage including the ripple component from the converter section into an AC voltage and outputs the AC voltage to a motor. The control device, in a rotating coordinate in which an N-pole direction of a permanent magnet embedded in a rotor of the motor is taken as a d-axis and a direction orthogonal to the d-axis is taken as a q-axis, controls the inverter section so that a phase of a d-axis voltage Vd of the ripple component included in the DC voltage leads a phase of a q-axis voltage Vq.

Inverter with reduced output ripple

A subtractor subtracts an angular speed correction amount from a rotational speed command to obtain a corrected rotational speed command. An adder adds a second-axis current correction value to a &#x3b3;c-axis current to obtain a corrected second-axis current. An angular ripple extraction unit obtains, from a rotational angle on a mechanical angle of a synchronous motor, a rotational angle difference being a ripple component of the rotational angle. An n-order component extraction unit extracts n-order components of a fundamental frequency of the rotational angle from the rotational angle difference. A torque conversion unit obtains n-order components of an estimated value of vibration torque. A correction amount calculation unit obtains the second-axis current correction value using the n-order components.

Speed command correction device and primary magnetic flux command generation device

A feedback amount calculation unit uses a deviation of a current from its command value or a deviation of an air-gap flux from its command value to calculate a feedback amount. A voltage error calculation unit calculates a variation range of a voltage error between a voltage value based on a voltage equation of the electric motor and a voltage command. The presence or absence of step-out of the electric motor is determined by comparison between the variation range of the voltage error and the feedback amount.

Controller for electric motor

A primary magnetic flux command value is changed in accordance with a torque of a rotary electric motor to control a current phase of an armature current with respect to a q axis that advances by &#x3c0;/2 with respect to a d axis in phase with a field flux to be a desired phase in accordance with the torque.

Primary magnetic flux control method

A difference command generator generates a difference command equivalent to a time integral of three-phase voltage applied to an inductive load in a predetermined cycle in a complex plane. A vector command generator generates vector commands that are respectively time integrals of voltage vectors and compose the difference command. A switching signal generator generates switching signals for controlling three pairs of switches in an inverter on the basis of the vector commands. A phase-current computing unit obtains an estimated value for the three-phase current on the basis of a current flowing DC buses and the vector commands. At least two of the vector commands that are time integrals of different ones of the non-zero voltage vectors have magnitudes greater than or equal to a predetermined value corresponding to a minimum required amount of time to maintain switching patterns in order for the phase-current computing unit to detect the current.

Power converter controller

An electric motor controller includes a first coordinate conversion unit that converts a three-phase current into a current in a &#x3b4;c-&#x3b3;c rotating coordinate system, a first calculation unit that obtains a first term, a second calculation unit that obtains a voltage command value in the &#x3b4;c-&#x3b3;c rotating coordinate system as a sum of the first term and a second term, a second coordinate conversion unit that coordinate-converts the voltage command value into a voltage command value of a voltage to be applied to a rotary electric motor in another coordinate system.

Electric motor controller

A carrier generating unit applies a carrier that monotonically decreases to a switching control unit during either one of a first period that is a period immediately following a period in which a voltage command value is a value not more than a minimum value of the carrier, the voltage command value taking a first predetermined value larger than the minimum value of the carrier in the first period, and a second period that is a period immediately preceding a period in which the voltage command value is not less than a maximum value of the carrier, the voltage command value taking a second predetermined value smaller than the maximum value in the second period.

Power conversion apparatus

A boot capacitor that functions as an operating power supply for a high-arm-side transistor provided in an inverter has to be charged prior to normal operation of a motor. This operation of charging the boot capacitor is performed at a carrier frequency that is lower than a carrier frequency for the normal operation.

Inverter driven compressor operation method and compressor drive device

A motor control apparatus comprises the amplitude adjustment section and the peak voltage control section so as to adjust the torque control output in correspondence with the output voltage of the inverter. The peak voltage control section detects the peak voltage of the voltage command, and outputs the adjustment command instructing the amplitude adjustment section to suppress the amplitude when the peak voltage possibly exceed the previously determined value which is determined with respect to the maximum output voltage or maximum modulation rate of the inverter. The amplitude adjustment section lowers the gain by carrying out processing such that a constant proportional value is removed from the integration value, for example, in response to the supplying of the adjustment command.

Growing community of inventors

Osaka, Japan

Nobuki Kitano