Abstract: A load apparatus is connected to an AC power source and is supplied with power from the AC power source. An operation state control unit controls, based on a target value about a power-source quality including either a power-source power factor of the AC power source or a power-source harmonic of the AC power source and on a present power-source quality, an operation state of the load apparatus.

Abstract: A plurality of active filter devices (41, 42, 43) that each have an output connected to a harmonic-generating load device (2) and are capable of generating a compensating current for performing at least one of reduction of a harmonic current of the harmonic-generating load device (2) and improvement of the power factor of the fundamental wave are provided. The plurality of active filter devices (41, 42, 43) provide two or more types of capacities, and the number and combination of operating active filter devices among the active filter devices (41, 42, 43) change in accordance with the magnitude of the compensating current.

Abstract: Disclosed is a control device controlling an operation of an active filter which is connected in parallel with a load at an installation point (P) with respect to an AC power source and which supplies a compensation current (Ic) to the installation point (P) so as to compensate for a harmonic component of a load current (Io) flowing through the load.

Abstract: Disclosed herein is a technique for reducing harmonics resulting from the rotation of a motor and generated in a power supply current. This power converter device includes a compensation current generator (52) configured to control compensation currents (Icr, Ics, Ict) flowing between itself (52) and an AC power supply (12), and a compensation controller (60; 260) configured to obtain output voltage instruction values (Vid, Viq) such that the compensation currents (Icr, Ics, Ict) cancel a harmonic component in load currents (Ir, Is, It) flowing from the AC power supply (12) into a rectifier (22) and resulting from the rotation of the motor (16) and a harmonic component in the load currents (Ir, Is, It) and dependent on a period (Ts) of a voltage of the AC power supply (12).

Abstract: Disclosed is a control device controlling an operation of an active filter which is connected in parallel with a load at an installation point (P) with respect to an AC power source and which supplies a compensation current (Ic) to the installation point (P) so as to compensate for a harmonic component of a load current (Io) flowing through the load.

Abstract: In a device with a built-in active filter, the device incorporating an active filter therein and being connected to an AC power source, the active filter operates based on a value detected by a load information detection unit detecting load information on an AC power source outside the device with a built-in active filter.

Abstract: A current source capable of generating a current of a first compensation portion for either or both reducing a harmonic current in an air conditioner or improving a fundamental power factor in the air conditioner is provided. If an excess of the current source is larger than a second compensation portion for either or both reducing a harmonic current in a power receiving path of a distribution board or improving a fundamental power factor in the power receiving path of the distribution board, a current obtained through superimposition of a current of a second compensation component and a current of the first compensation component is generated in the current source.

Abstract: An active filter is connected in parallel to a rectifier circuit between a set of AC input lines and a pair of DC buses. The active filter includes a capacitor, a pair of current limiting elements and an inverter. One in the current limiting elements is disposed between one end of the capacitor and one in the DC buses. Other in the current limiting elements is disposed between other end of the capacitor and other in the DC buses. At least one of the current limiting elements is disposed in an orientation to be forward with respect to a DC voltage outputted by the rectifier circuit. The inverter includes: a set of AC-side terminals connected to the set of AC input lines; and a pair of DC-side terminals connected to both ends of the capacitor.

Abstract: A control device outputs, to a to-be-controlled system which operates based on a control input and from which an observable amount varying cyclically is obtained, the control input based on the observable amount. The control device includes a deviation processing unit performing at least proportional integral control on a deviation between the observable amount and a command value being a target value of the observable amount and varying cyclically, and a totaling unit totaling an output of the deviation processing unit for each cycle of the command value to generate the control input.

Abstract: A harmonic component extraction unit obtains a command value of compensating current from a harmonic component of the load current. A difference current generation unit obtains a deviation between the compensating current and a value obtained by leading a phase of the command value by a predetermined phase difference. A current controller generates a control signal based on output of the difference current generation unit. A driving signal generation circuit generates, based on the control signal, a driving signal driving a parallel active filter.

Abstract: An active filter is connected in parallel to a rectifier circuit between a set of AC input lines and a pair of DC buses. The active filter includes a capacitor, a pair of current limiting elements and an inverter. One in the current limiting elements is disposed between one end of the capacitor and one in the DC buses. Other in the current limiting elements is disposed between other end of the capacitor and other in the DC buses. At least one of the current limiting elements is disposed in an orientation to be forward with respect to a DC voltage outputted by the rectifier circuit. The inverter includes: a set of AC-side terminals connected to the set of AC input lines; and a pair of DC-side terminals connected to both ends of the capacitor.

Abstract: Disclosed herein is a technique for reducing harmonics resulting from the rotation of a motor and generated in a power supply current. This power converter device includes a compensation current generator (52) configured to control compensation currents (Icr, Ics, Ict) flowing between itself (52) and an AC power supply (12), and a compensation controller (60; 260) configured to obtain output voltage instruction values (Vid, Viq) such that the compensation currents (Icr, Ics, let) cancel a harmonic component in load currents (Ir, Is, It) flowing from the AC power supply (12) into a rectifier (22) and resulting from the rotation of the motor (16) and a harmonic component in the load currents (Ir, Is, It) and dependent on a period (Ts) of a voltage of the AC power supply (12).

Abstract: A control device outputs, to a to-be-controlled system which operates based on a control input and from which an observable amount varying cyclically is obtained, the control input based on the observable amount. The control device includes a deviation processing unit performing at least proportional integral control on a deviation between the observable amount and a command value being a target value of the observavle amount and varying cyclically, and a totaling unit tataling an output of the deviation processing unit for each cycle of the command value to generate the control input.

Abstract: A harmonic component extraction unit obtains a command value of compensating current from a harmonic component of the load current. A difference current generation unit obtains a deviation between the compensating current and a value obtained by leading a phase of the command value by a predetermined phase difference. A current controller generates a control signal based on output of the difference current generation unit. A driving signal generation circuit generates, based on the control signal, a driving signal driving a parallel active filter.

Abstract: A bidirectional switch circuit includes two switching elements connected to conduct a current in both directions. The two switching elements are connected in series to each other. Of the two switching elements, the switching element to which a reverse voltage is applied, a voltage of a source of one of the switching elements being higher than a voltage of a drain of the one, is configured to conduct a current from the source to the drain even when an on-drive signal is not being input to a gate terminal of the one.

Abstract: A motor control unit (10) includes: a power converter (40) having a rectifier circuit (20) which rectifies an AC voltage from an AC power supply (31), a capacitor circuit (22) which receives an output of the rectifier circuit (20) and outputs a rectified voltage having pulses from both ends of a capacitor (13) and an inverter circuit (25) which receives the rectified voltage and outputs an AC voltage to the motor (30); and a motor controller (41) controlling the motor (30) by controlling the inverter circuit (25). The motor controller (41) performs torque control to vary an output toque of the motor (30) in response to variation in load torque of the motor (30).

Abstract: In the case where a chip is made of wide band gap semiconductor, a power conversion apparatus is obtained in which a component having a low heat resistant temperature is prevented from receiving thermal damage by heat generated at the chip. In a configuration including: a chip portion (20) including a chip (21) made of wide band gap semiconductor and a member (22, 23) having a heat resistant temperature equal to or higher than that of the chip (21); and a peripheral component (25) arranged in the vicinity of the chip portion (20) and having a heat resistant temperature lower than that of the chip (21). The chip (21) and the peripheral component (25) are thermally insulated from each other so that the temperature of the peripheral component (25) does not exceed the heat resistant temperature of the peripheral component (25).

Abstract: A power converter is provided with a rectifying circuit, an inverter circuit, and a common mode filter including a common mode choke coil and a capacitor. The switching frequency of a PWM rectifying circuit is set at three times the switching frequency of a PWM inverter. Alternatively, the resonance frequency of the common mode filter is set at twice the carrier frequency of the rectifying circuit or the PWM inverter circuit or more.

Abstract: A PI control section performs a PI control on a deviation which is a difference between a DC voltage command and a DC voltage, and outputs a d-axis current command value. A PI control section performs a PI control on a deviation which is a difference between the d-axis current command value and a d-axis current, and outputs a d-axis voltage command value. Based on the d-axis voltage command value and a q-axis voltage command value, a PWM control section outputs a switching control signal for controlling a switching operation of a converter. A voltage command computation section generates the DC voltage command based on the d-axis voltage command value.

Abstract: A bidirectional switch circuit includes two switching elements connected to conduct a current in both directions. The two switching elements are connected in series to each other. Of the two switching elements, the switching element to which a reverse voltage is applied, a voltage of a source of one of the switching elements being higher than a voltage of a drain of the one, is configured to conduct a current from the source to the drain even when an on-drive signal is not being input to a gate terminal of the one.