Abstract: A construction machine includes an attitude sensor that detects the current attitude of an upper turning body; a reference angular acceleration calculation unit that calculates a reference angular acceleration to be generated when an electric turning motor is driven by a torque command value generated according to the operation amount of an operation part; a reference gravity torque calculation unit that, on the basis of the current attitude and the deviation between an actual angular acceleration, calculates a reference gravity torque; a gravity compensation torque calculation unit that calculates a gravity compensation torque for compensating a torque component generated about the turning axis by the gravity in the current attitude; and a correction unit that corrects the torque command value by using the gravity compensation torque so as to cancel the torque component generated about the turning axis by the gravity in the current attitude.

Abstract: A power conversion device includes: a DC/DC convertor (5) that performs DC/DC conversion on an output voltage of a direct-current power supply (for example, a solar battery module (1)); and a DC/AC invertor (6) that performs DC/AC conversion on an output voltage of the DC/DC convertor (5). The output power of the DC/AC invertor (6) is controlled such that the charge and discharge of a storage device (for example, a storage battery (3)) connected to a connection point between an output end of the DC/DC convertor (5) and an input end of the DC/AC invertor (6) are controlled.

Abstract: A power conversion device includes: a DC/DC convertor (5) that performs DC/DC conversion on an output voltage of a direct-current power supply (for example, a solar battery module (1)); and a DC/AC invertor (6) that performs DC/AC conversion on an output voltage of the DC/DC convertor (5). The output power of the DC/AC invertor (6) is controlled such that the charge and discharge of a storage device (for example, a storage battery (3)) connected to a connection point between an output end of the DC/DC convertor (5) and an input end of the DC/AC invertor (6) are controlled.

Abstract: There is provided an inverter apparatus islanding operation detecting method capable of surely detecting an islanding operation with a simple construction. A distortion for causing a variation in an output frequency of an inverter apparatus in an islanding operation stage is applied to an inverter output waveform. With this arrangement, even when the inverter apparatus is disconnected from an AC power system in a state in which a power factor of a load impedance is proximate to one, a frequency variation is generated in an inverter output, thereby ensuring detection of the islanding operation.

Abstract: An inverter-control device includes a subtractor for detecting an error between a waveform of a reference current signal generated in synchronization with a waveform of an inverter output current signal and the inverter output current signal, a delay portion for delaying by a prescribed time period a signal obtained by amplifying and removing high frequency component by filtering the error, an error waveform integrating portion for integrating the delayed signal f' output from delay portion, a proportional control portion for amplifying the error, and an adding portion for adding an error amplified signal output from the proportional control portion and an inverter driving waveform pattern output from the error waveform integrating portion.

Abstract: An active controller suppressing an incoming acoustic wave by active control includes a signal processing unit filtering, an input signal corresponding to the incoming acoustic wave to generate an output signal, an error detecting portion detecting an error between the output signal and a desired response value, and an adapting portion adjusting a filtering characteristic of the signal processing portion according to the input signal, the output signal, and an error signal such that the error is minimized. The signal processing portion includes a non-recursive all zero digital filter filtering an input signal, and a lattice-type multi-stage all pole digital filter further filtering an output signal of the non-recursive all zero digital filter. The adapting portion updates a filter coefficient of the signal processing portion adaptively while clipping an absolute value exceeding one of a filter coefficient of the lattice-type multi-stage all pole digital filter.

Abstract: A pulse width of a pulse train signal used for PWM (pulse width modulation) control is monitored. When a variation of the pulse width substantially disappears within a specified time, it is determined that an operating point on an output characteristic curve of a photovoltaic array is located on the open-circuit voltage side of a maximum power point. When the variation of the pulse width does not disappear after the elapse of the specified time, it is determined that the operating point is located on the short-circuit current side of the maximum power point. Based on the determination result, the inverter control is performed such that the operating point follows the maximum power point.

Abstract: In a method of controlling an inverter for adjusting a periodic inverter output waveform to a desired periodic waveform, an error waveform pattern between an inverter output waveform of the present prescribed period and a desired periodic waveform generated in synchronization with the prescribed period is formed, and the error waveform pattern is added to an inverter driving waveform pattern in the last prescribed period, whereby an inverter driving waveform pattern is updated.

Abstract: An active control apparatus using an adaptive IIR digital filter includes a coefficient control portion for updating the filter coefficient of adaptive IIR digital filter so as to minimize an output error signal level, and a coefficient control portion for updating the filter coefficient of a recursive portion so as to minimize the output level of recursive portion. The filter coefficient of recursive filter is updated by these two coefficient control portions and in parallel or in a time-dividing manner.

Abstract: A main adaptive digital filter and a sub adaptive digital filter are provided, and these two adaptive digital filters share a filter coefficient to be controlled. On the side of the main adaptive digital filter, the shared coefficient is updated so that the difference between the output and a desired response is minimized and on the side of the subadapted digital filter, the above-stated shared filter coefficient is updated so that the output is minimized. A prescribed limitation is given to the frequency characteristic of a filter coefficient to be adapted, by treating the input of the sub adaptive digital filter as a signal weighted on the frequency or a noise having its band limited with respect to the input signal or the output signal of the main adaptive digital filter, and coefficient updating control is conducted so that the coefficient will not go beyond the limitation.

Abstract: A fan device for a refrigerator includes a hollow wall having a front wall portion and a rear wall portion for dividing an interior space of the refrigerator into a heat exchanging zone and a first portion of a storage zone. An air suction opening is formed in the rear wall portion for allowing an air cooled in the heat exchanging zone to be induced into the hollow wall. A fan is disposed in alignment with the air suction opening so as to induce the cooled air. A plurality of forward air outlet slots are formed in the front wall portion for allowing the air in the hollow wall to be blown to the first portion of the storage zone. A rearward air outlet is formed in the rear wall portion for allowing the air in the hollow wall to be blown to a second portion of the storage zone through a duct communicating the rearward air outlet to the second portion.

Abstract: A refrigerator which includes cooling chamber including a refrigerating chamber and a freezing chamber, an axial flow fan for circulating air within the cooling chamber, a heat exchanger for cooling the air circulated by the axial flow fan, a suction side space so formed as to guide the air cooled by the heat exchanger from the heat-exchanger to the axial flow fan, and a sound absorbing material for absorbing noises produced in the suction side space and the cooling chamber so as not to leak outside the refrigerator, with the suction side space and the cooling chamber respectively having resonance dimensions for resonation at specific frequency regions. The suction side space is set, in its resonance dimension, to the frequency region at which the sound absorbing material can absorb the sound in an efficient manner.