Daikin Industries, Ltd.

Takayuki Fujita

Reiji Kawashima

Masaki Kono

Kenichi Sakakibara

Masaki Kouno

A plurality of active filter devices () that each have an output connected to a harmonic-generating load device () 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 () and improvement of the power factor of the fundamental wave are provided. The plurality of active filter devices () provide two or more types of capacities, and the number and combination of operating active filter devices among the active filter devices () change in accordance with the magnitude of the compensating current.

Active filter system and air conditioning device

A controller performs a first control for controlling the power source power factor or a power source harmonic of the harmonic current such that an input power factor of at least one of a plurality of connection devices changes in a direction preceding the power source power factor in a case where the power source power factor changes in a lagging direction, and performs a second control for controlling the power source power factor or the power source harmonic such that the input power factor of at least one of the connection devices changes in a direction lagging behind the power source power factor in a case where the power source power factor changes in a leading direction.

Power source quality management system and air conditioner

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.

Power-source power factor control system, phase modifying apparatus, and active filter apparatus

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.

Active filter device, air conditioning device, and air conditioning system

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.

Device with built-in active filter

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.

Active filter and AC-DC conversion device

When an AC voltage is outputted to an inductive load, pulsation of an effective power caused by an odd number-th order harmonic component of a current flowing in this load is reduced. A modulation factor k of an inverterincludes a DC component kand an AC component. The AC component includes a frequency which is a 6n multiple of the fundamental frequency of AC voltages outputted from the inverter. Even when there are not only the 5th order harmonic component of load currents but also the 7th order harmonic component, it is possible to adequately set the ratio of the magnitude of the AC component and the ratio of the DC component and reduce pulsation of consumption power caused by these harmonic components. Reducing the pulsation contributes to suppression of power harmonics.

Power converter control method

A converter includes switching devices connected between each of a plurality of input ends and a DC power supply line, and switching devices connected between each of the plurality of input ends and a DC power supply line. A capacitor, a resistor and a diode are connected in series with each other between the DC power supply lines.

Power converter having clamp circuit with capacitor and component for limiting current flowing into capacitor

A command value is a current command value with a triangular-like waveform having a cycle that is &#x2153; of a cycle of a three-phase voltage. A carrier has a triangular-like waveform having a cycle shorter than the cycle of the command value. Comparison result signals are pulse signals indicating a result of the comparison between the carrier and the command value. In a region of a phase of 30 to 90 degrees, a portion of the comparison result signal present in this region is employed as a gate signal. In a region of a phase of 270 to 330 degrees, a portion of the comparison result signal present in this region is employed as the gate signal.

AC/DC converter device

A converter section () includes three pairs of switching elements (Srp, . . . , Stn), each pair having two switching elements connected in series between two direct current links (L, L), and phases of an input three-phase alternating current are connected to nodes between the series-connected switching elements one by one. Each of the switching elements (Srp, . . . , Stn) is made of a transistor having a bipolar structure. The control unit () controls the switching elements (Srp, . . . , Stn) such that line voltages between a reference phase, which is one of the phases of the input three-phase alternating current, and each of the other phases are output to the two direct current links (L, L) on a time division basis. The control unit () applies a predetermined gate voltage to one or more of the switching elements (Srp, . . . , Stn) to which a reverse bias is applied.

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Osaka, Japan

Takayuki Fujita