Abstract: A power supply device is provided with a diode rectifier circuit having an input connected to an AC power source, the output of the diode rectifier circuit producing a rectified voltage; a capacitor connected to the diode rectifier to be charged by the rectified voltage; and a controller configured to receive as input a detection signal representing a charging current flowing into the capacitor, the controller being further configured to calculate a voltage frequency, a cycle, or a power voltage phase of the AC power on the basis of the detection signal. At least one of the following is used to detect the charging current flowing into the capacitor and produce the detection signal: a photocoupler; an amplifier circuit including a shunt resistor and an operational amplifier; and a current transformer.

Abstract: A power conversion device includes a single phase full-bridge rectification circuit, a reactor being connected to a power source in series between one of input terminals of the single phase full-bridge rectification circuit and the power source, capacitors being connected to each other in series via a connection point between output terminals of the single phase full-bridge rectification circuit, a first switch connected between the input terminal and the connection point, and a second switch connected between the input terminals.

Abstract: A power conversion device includes a single phase full-bridge rectification circuit, a reactor being connected to a power source in series between one of input terminals of the single phase full-bridge rectification circuit and the power source, capacitors being connected to each other in series via a connection point between output terminals of the single phase full-bridge rectification circuit, a first switch connected between the input terminal and the connection point, and a second switch connected between the input terminals.

Abstract: A power supply device is provided with a diode rectifier circuit having an input connected to an AC power source, the output of the diode rectifier circuit producing a rectified voltage; a capacitor connected to the diode rectifier to be charged by the rectified voltage; and a controller configured to receive as input a detection signal representing a charging current flowing into the capacitor, the controller being further configured to calculate a voltage frequency, a cycle, or a power voltage phase of the AC power on the basis of the detection signal. At least one of the following is used to detect the charging current flowing into the capacitor and produce the detection signal: a photocoupler; an amplifier circuit including a shunt resistor and an operational amplifier; and a current transformer.

Abstract: A power converter including a compressor as a load includes a compensation current output (80) allowing compensation current (Ic), which compensates for leakage current (Ia), to flow. A controller (50) receives a detection signal from a rotational speed sensor (55) which senses the rotational speed of the compressor (CM). When the rotational speed has increased to a set rotational speed at which the leakage current (Ia) is lower than or equal to its limiting value (Lmax) (e.g., the limiting value specified under the Electrical Appliances and Materials Safety Act or by the IEC) in a state where the compensation current output (80) is off, the compensation current output (80) is switched from an on state to an off state. This may reduce the leakage current from the compressor with low power loss.

Abstract: A power converter including a compressor as a load includes a compensation current output (80) allowing compensation current (Ic), which compensates for leakage current (Ia), to flow. A controller (50) receives a detection signal from a rotational speed sensor (55) which senses the rotational speed of the compressor (CM). When the rotational speed has increased to a set rotational speed at which the leakage current (Ia) is lower than or equal to its limiting value (Lmax) (e.g., the limiting value specified under the Electrical Appliances and Materials Safety Act or by the IEC) in a state where the compensation current output (80) is off, the compensation current output (80) is switched from an on state to an off state. This may reduce the leakage current from the compressor with low power loss.

Abstract: A mode controller shifts, along with increase in an electric power in first and second of chopper circuits and, operation modes of the first and the second of the chopper circuits from a first mode to a third mode via a second mode. An operation controller causes, in the first mode, the first of chopper circuit to perform an chopping operation, and the second of chopper circuit to suspend the chopping operation, in the second mode, causes the first and the second of chopper circuits to alternatively perform the chopping operations, and in the third mode causes both of the first and the second of chopper circuits to perform the chopping operations.

Abstract: A mode controller shifts, along with increase in an electric power in first and second of chopper circuits and, operation modes of the first and the second of the chopper circuits from a first mode to a third mode via a second mode. An operation controller causes, in the first mode, the first of chopper circuit to perform an chopping operation, and the second of chopper circuit to suspend the chopping operation, in the second mode, causes the first and the second of chopper circuits to alternatively perform the chopping operations, and in the third mode causes both of the first and the second of chopper circuits to perform the chopping operations.

Abstract: A mode controller shifts, along with increase in an electric power in first and second of chopper circuits and, operation modes of the first and the second of the chopper circuits from a first mode to a third mode via a second mode. An operation controller causes, in the first mode, the first of chopper circuit to perform an chopping operation, and the second of chopper circuit to suspend the chopping operation, in the second mode, causes the first and the second of chopper circuits to alternatively perform the chopping operations, and in the third mode causes both of the first and the second of chopper circuits to perform the chopping operations.