A compressor driving device includes a three-phase alternating current power supply input end, a relay module, a rectifier circuit, and a driving control circuit which are sequentially connected; the rectifier circuit is used for converting connected alternating current into direct current and then outputting the direct current to a direct current bus; the driving control circuit is used for converting the direct current output by the direct current bus into compressor driving power; a pressure switch is used for measuring the pressure value in a refrigerating system, and when the measured pressure value is larger than a preset pressure threshold, disconnecting the power supply circuit of the relay module; the driving control circuit is also used for detecting the on-off state of the pressure switch and controlling the compressor to stop working when the pressure switch is switched off.

A heat pump is provided that may include an indoor unit including an indoor heat exchanger; an outdoor unit including an outdoor heat exchanger and a compressor that compresses a refrigerant; a housing that forms an outer shape of the outdoor unit and provides an internal space in which the outdoor heat exchanger and the compressor are disposed; a partition wall that is disposed in the internal space of the housing, and divides the internal space into a flow path space in which the outdoor heat exchanger is disposed and a cycle space in which the compressor is disposed; an outdoor fan disposed in the flow path space to cause an air flow; and a controller that controls an operation of the compressor and the outdoor fan. The housing may include a hole that communicates with the cycle space, and the partition wall may include a barrier hole that communicates the flow path space and the cycle space.

The refrigeration cycle apparatus (1) includes a refrigerant circuit (2) that includes a flow channel (29a) through which a refrigerant in a liquid single-phase state flows, and a filter member (35) that is provided in the flow channel (29a) and that captures acid contained in the refrigerant, which passes through the flow channel.

A device management system for an inverter compressor is a device management system for an inverter compressor provided with a motor to be driven by an inverter, and includes: a partial discharge detector that detects a voltage of the motor to detect a partial discharge that occurs in the motor; and a determination module that determines whether there is a risk of occurrence of the partial discharge or whether the partial discharge occurs based on a result of detection by the partial discharge detector. When the voltage detected by the partial discharge detector is higher than a first threshold, the determination module determines that there is a risk of the occurrence of the partial discharge or the partial discharge occurs, and performs a protective operation to reduce the risk of the occurrence of the partial discharge in the motor or the occurrence of the partial discharge in the motor.

A direct current power supply device includes: a reactor; a converter connected to an alternating current power supply via the reactor; a smoothing capacitor connected between output terminals of the converter; an inrush current preventing circuit disposed on a charging path from the alternating current power supply to the smoothing capacitor; a current detection unit detecting direct current representing an operating state on an output side of the converter; a current detection unit detecting power supply current representing an operating state on an input side of the converter; and a control unit receiving the direct current and the power supply current and controlling an operation of the converter. The control unit receives a detected value of saturated current from at least one of the direct current and the power supply current when the power supply voltage recovers from a state in which the power supply voltage is reduced.

A compressor retrofit assembly for replacing a D/C compressor with an A/C compressor includes a control unit that is installable in a refrigerator when the compressor in the refrigerator has failed. The control unit is electrically coupled with an existing power supply in the refrigerator, a compressor relay of a replacement compressor for the refrigerator, an existing power input of a fan in the refrigerator and a coil of the compressor relay of the replacement compressor. The control unit supplies electrical power to the coil of the compressor relay thereby facilitating the compressor relay to be closed. In this way the control unit supplies operational voltage to the replacement compressor.

A HVAC system refrigeration circuit is provided. Embodiments of the present disclosure relate to a refrigeration circuit configured to balance the oil carryover between multiple compressors using a single refrigeration circuit. Embodiments of the present disclosure allow for the use of one or more inverter compressors and one or more fixed speed compressors. Embodiments of the present disclosure utilize capillary tubes or other flow control methods to balance the oil carryover between multiple compressors.

The motor driving apparatus includes a switch that is a mechanical switch for changing coil connection states of a motor; an inverter that generates alternating voltage from direct voltage and outputs the alternating voltage to the motor; and a control device that controls the switch and the inverter. The control device causes the switch to change the coil connection states while the alternating voltage output from the inverter is zero.

A motor driving device that drives a motor and is capable of switching a connection state of stator windings of the motor, includes: relays to switch the connection state of the stator windings by switching positions of contact plates; and a contact control unit to control each of the positions of the contact plates by outputting, to the relays, signals for actuating the contact plates. The contact control unit switches the connection state by sequentially switching output values of the signals such that the output values of the signals are switched at different timings from each other in the relays, and changes a switching order every time the connection state is switched, the switching order being an order in which the output values of the signals are switched.

There is provided a starting method for a cryocooler, the cryocooler including a compressor, a cold head, a high pressure line, and a low pressure line, the method including increasing a volume of the high pressure line when the cold head is at a room temperature, cooling the cold head from the room temperature to a cryogenic temperature while controlling an operation frequency of the compressor based on a pressure of the high pressure line or a differential pressure between the high pressure line and the low pressure line, after the volume of the high pressure line has been increased, decreasing the volume of the high pressure line after the cold head has been cooled to the cryogenic temperature, and maintaining the cold head at the cryogenic temperature after the volume of the high pressure line has been decreased.