Abstract: To improve the accuracy of detecting a current flowing through an electric compressor after operation of the electric compressor, the electric compressor having a large change in temperature before and after operation. An inverter-integrated electric compressor (1) that compresses and discharges a refrigerant suctioned therein, includes an inverter device (2) provided with a circuit board (60) mounted with an inverter circuit (40), the inverter device (2) being integrally incorporated in an inverter case. The circuit board (60) is provided with a current detection circuit (30) that detects an input current flowing through the inverter circuit (40), and an offset correction circuit (20). The current detection circuit (30) includes a shunt resistor (32) that is serially connected to the inverter circuit (40) and detects a current, and a first amplifier (31) that amplifies and outputs a voltage appearing as a voltage drop in the shunt resistor (32).

Abstract: To improve the accuracy of detecting a current flowing through an electric compressor after operation of the electric compressor, the electric compressor having a large change in temperature before and after operation. An inverter-integrated electric compressor (1) that compresses and discharges a refrigerant suctioned therein, includes an inverter device (2) provided with a circuit board (60) mounted with an inverter circuit (40), the inverter device (2) being integrally incorporated in an inverter case. The circuit board (60) is provided with a current detection circuit (30) that detects an input current flowing through the inverter circuit (40), and an offset correction circuit (20). The current detection circuit (30) includes a shunt resistor (32) that is serially connected to the inverter circuit (40) and detects a current, and a first amplifier (31) that amplifies and outputs a voltage appearing as a voltage drop in the shunt resistor (32).

Abstract: To improve the accuracy of detecting a current flowing through an electric compressor after operation of the electric compressor, the electric compressor having a large change in temperature before and after operation. An inverter-integrated electric compressor (1) that compresses and discharges a refrigerant suctioned therein, includes an inverter device (2) provided with a circuit board (60) mounted with an inverter circuit (40), the inverter device (2) being integrally incorporated in an inverter case. The circuit board (60) is provided with a current detection circuit (30) that detects an input current flowing through the inverter circuit (40), and an offset correction circuit (20). The current detection circuit (30) includes a shunt resistor (32) that is serially connected to the inverter circuit (40) and detects a current, and a first amplifier (31) that amplifies and outputs a voltage appearing as a voltage drop in the shunt resistor (32).

Abstract: In an inverter control apparatus, a phase current calculation section calculates each of phase currents flowing into a motor by using measurement results of a current sensor, and a voltage command generation section calculates three-phase voltage commands by using each of the estimated phase currents. A command modulation section compares the phase voltage commands with each other, to specify a full-on phase or a full-off phase on the basis of the comparison result and then to set the voltage command of the specified phase to a full-on voltage or a full-off voltage, and offsets the voltage commands of the other two phases according to the full-on voltage or the full-off voltage to modulate the voltage commands into voltage commands allowing the line voltage between the other two phases to be kept constant.

Abstract: A power-converter controller is provided in a wind turbine generator which is interconnected to a utility grid and in which a generator generates electrical power by rotation of a rotor having blades. The power-converter controller includes a voltage sensor that measures a generator terminal voltage, resonance-component extracting sections that extract an electrical resonance component generated due to the interconnection from a measurement result measured by the voltage sensor, and a control section and a control section that control a current that flows to the utility grid so as to suppress the resonance component, on the basis of the resonance component extracted by the resonance-component extracting sections. Accordingly, the power-converter controller can more effectively suppress the resonance generated due to the interconnection of the wind turbine generator to the utility grid.

Abstract: In an inverter control apparatus, a phase current calculation section calculates each of phase currents flowing into a motor by using measurement results of a current sensor, and a voltage command generation section calculates three-phase voltage commands by using each of the estimated phase currents. A command modulation section compares the phase voltage commands with each other, to specify a full-on phase or a full-off phase on the basis of the comparison result and then to set the voltage command of the specified phase to a full-on voltage or a full-off voltage, and offsets the voltage commands of the other two phases according to the full-on voltage or the full-off voltage to modulate the voltage commands into voltage commands allowing the line voltage between the other two phases to be kept constant.

Abstract: An object of the present invention is to achieve stable inverter control by means of current detection using one current sensor in all of periods in which overmodulation control is performed. An inverter controller includes a ?-axis current calculation section that holds, in advance, a ?-axis current arithmetic expression including a direct current as a parameter, and calculates a ?-axis current using a direct current detected by a current sensor for the ?-axis current arithmetic expression.

Abstract: To suppress a ripple contained in current flowing into a DC power supply during one-pulse control in a motor drive apparatus receiving electric power from the DC power supply. A motor drive apparatus 1 includes an inverter control device (10) provided with a one-pulse control mode in which, during one electrical angle cycle, a positive rectangular pulse voltage and a negative rectangular pulse voltage are applied, as gate drive signals, to a switching element corresponding to each phase. When performing the one-pulse control mode, the inverter control device (10) gradually increases or reduces a duty in a predetermined phase angle width at rising and falling edges of the rectangular wave voltage.

Abstract: To suppress a ripple contained in current flowing into a DC power supply during one-pulse control in a motor drive apparatus receiving electric power from the DC power supply. A motor drive apparatus 1 includes an inverter control device (10) provided with a one-pulse control mode in which, during one electrical angle cycle, a positive rectangular pulse voltage and a negative rectangular pulse voltage are applied, as gate drive signals, to a switching element corresponding to each phase. When performing the one-pulse control mode, the inverter control device (10) gradually increases or reduces a duty in a predetermined phase angle width at rising and falling edges of the rectangular wave voltage.

Abstract: An object of the present invention is to achieve stable inverter control by means of current detection using one current sensor in all of periods in which overmodulation control is performed. An inverter controller includes a ?-axis current calculation section that holds, in advance, a ?-axis current arithmetic expression including a direct current as a parameter, and calculates a ?-axis current using a direct current detected by a current sensor for the ?-axis current arithmetic expression.

Abstract: The present invention has an object to detect a three-phase AC motor current with high accuracy only with DC input current measuring means to a three-phase PWM inverter, and reduce resonance of a DC power supply by a ripple current in driving an AC motor with a DC current via a three-phase PWM inverter. A carrier wave Cry_e earlier than that of a V phase is used to sample a U phase and a carrier wave Cry_l always later than that of the V phase is used to sample a W phase. Thus, a sampling time sufficiently longer than an interval Ts of the carrier waves Cry_e, Cry_m and Cry_l can be ensured, and the current can be easily detected.

Abstract: There is provided an electric compressor capable of being actuated rapidly. During the time when the operation of an automotive air conditioner is stopping, by heating a motor 12, a refrigerant on the outlet side 11b of a compressor body 11 is heated. Thereby, the temperature of refrigerant on the outlet side 11b is raised, and the refrigerant is prevented from being liquefied on the outlet side 11b of the compressor body 11, by which the automotive air conditioner can be actuated rapidly. Besides, by rotating the motor 12 at the number of revolutions lower than that at the time of normal operation, the refrigerant liquefied on the outlet side 11b of the compressor body 11 may be pushed out.

Abstract: The present invention has an object to detect a three-phase AC motor current with high accuracy only with DC input current measuring means to a three-phase PWM inverter, and reduce resonance of a DC power supply by a ripple current in driving an AC motor with a DC current via a three-phase PWM inverter. A carrier wave Cry_e earlier than that of a V phase is used to sample a U phase and a carrier wave Cry_l always later than that of the V phase is used to sample a W phase. Thus, a sampling time sufficiently longer than an interval Ts of the carrier waves Cry_e, Cry_m and Cry_l can be ensured, and the current can be easily detected.

Abstract: There is provided an electric compressor capable of being actuated rapidly. During the time when the operation of an automotive air conditioner is stopping, by heating a motor 12, a refrigerant on the outlet side 11b of a compressor body 11 is heated. Thereby, the temperature of refrigerant on the outlet side 11b is raised, and the refrigerant is prevented from being liquefied on the outlet side 11b of the compressor body 11, by which the automotive air conditioner can be actuated rapidly. Besides, by rotating the motor 12 at the number of revolutions lower than that at the time of normal operation, the refrigerant liquefied on the outlet side lib of the compressor body 11 may be pushed out.