Abstract: A refrigeration cycle apparatus having a linear compressor is provided with a volume circulation rate instruction unit for obtaining a volume circulation rate Vco of a refrigerant in accordance with refrigerating capacity required of the refrigeration cycle apparatus, on the basis of an ambient temperature of an indoor heat exchanger (evaporator), a target temperature set on the evaporator by the user, and an ambient temperature of an outdoor heat exchanger (condenser); a volume circulation rate detector for detecting a volume circulation rate Vcd of the refrigerant that actually circulates in a refrigerant circulation path of the refrigeration cycle apparatus; and an inverter for generating an AC current for driving the linear compressor; wherein the inverter is controlled so as to decrease a difference between the volume circulation rate Vco and the volume circulation rate Vcd.

Abstract: A linear compressor driving apparatus (101) according to the present invention is a linear compressor driving apparatus having an inverter (2) which supplies a driving current of a predetermined frequency to a linear compressor (100), and the apparatus further includes an inverter controller (6) for controlling the inverter (2) on the basis of resonance frequency information so that the frequency of an output current from the inverter becomes equal to the resonance frequency, and instantaneous values of an output current Id and an output voltage Vd from the inverter (2) are measured at a phase timing in which an amount of change in the output current Id of the inverter (2) becomes zero, and a piston stroke is calculated from these measured values. In such linear compressor driving apparatus (101), a stroke and a top clearance of the piston of the linear compressor can be accurately detected by relatively simple arithmetic processing, without using a position sensor.

Abstract: In a driving apparatus of a linear compressor 1 having a power source capable of controlling output current and measuring output electric power, frequency of the linear compressor 1 is controlled such that the amplitude of current which is supplied to the linear compressor 1 is made constant and electric power which is supplied to the linear compressor 1 becomes maximum. With this, it is possible to drive the linear compressor 1 efficiently while following the resonance frequency which keeps varying with variation of a load. Further, a current detecting means 8 capable of detecting output current and electric power from inverter input current is provided, and it is unnecessary to newly add a current sensor.

Abstract: A linear compressor driving device for linear compressor driving a piston in a cylinder by means of a linear motor to generate a compressed gas, has an inverter for outputting an alternating current to be supplied to the linear motor; current detecting means for detecting an output current from the inverter; voltage detecting means for detecting an output voltage from the inverter; current amplitude value determining means for determining a current amplitude value of the output current; output power calculating means for calculating an output power from the inverter based on the detected output current and the detected output voltage; frequency determining means for determining a frequency of the output current such that the output power is maximum; and inverter controller for controlling the inverter based on the determined current amplitude value and the determined frequency.

Abstract: The present invention provides a motor controller capable of driving a synchronous motor having no position sensor stably at high efficiency by carrying out simple control. In order to attain this purpose, a reactive current is obtained from a motor current and a rotation phase, an error voltage is obtained from the reactive current and the command value of the reactive current, thereby obtaining a motor applied voltage command value Va that is used to compensate for the V/f characteristic of the motor. Furthermore, the motor applied voltage command value Va is applied to an output command computing section, and computed with the rotation phase signal of a wave generation section, thereby obtaining a signal for PWM driving the switching devices of an inverter circuit.

Abstract: A converter circuit has a reactor connectable to an AC power supply. It further has a PWM converter circuit connected to the reactor, the PWM converter circuit including a high speed diode, a rectifier diode and a switching element connected in parallel to the rectifier diode. The converter circuit further has an input current detector for detecting an input current of the PWM converter circuit, a DC voltage level detector for detecting an output voltage of the PWM converter circuit, a voltage polarity detector connected to the AC power supply, and a control device. The control device measures a variation period of the output voltage measured by the voltage level detector to judge a power supply frequency. It then controls the PWM converter circuit based on a power supply frequency judgement result, a detection result from the voltage level detector, an input current detected by the input current detector, and an output voltage detected by the DC voltage detector.