The present invention relates to an air conditioner that adjusts room temperature to a set temperature, and the problem to be solved thereby is to reduce the frequency of occurrence of situations in which the room temperature does not approach the set temperature. In the air conditioner, a target suction pressure is set to a value obtained by subtracting, from an evaporation pressure of an indoor heat exchanger, a pressure loss estimation value from an inlet of the indoor heat exchanger to a suction port of a compressor so that an evaporation temperature of the indoor heat exchanger is maintained constant. The displacement of the compressor is controlled so that the suction pressure becomes equal to the target suction pressure. A deviation determination unit determines whether the room temperature is stabilized at a temperature deviated from the set temperature. When the deviation determination unit determines that the room temperature is deviated from the set temperature, a controller changes the pressure loss estimation value so that the room temperature approaches the set temperature.

Described are a compressor driving apparatus and a refrigerator including the same. The compressor driving apparatus includes: switching elements; an inverter; an output current detector for detecting an output current flowing through a motor; and an inverter controller for controlling the inverter. The inverter controller controls the piston so that one end of the piston is fixed at a first position spaced apart from the discharge unit at stroke of the piston during a first period, controls the piston to collide with the discharge unit when a change rate in an operation rate or a position error of the compressor is equal to or greater than a predetermined value, and controls the piston so that the one end of the piston is fixed at a second position spaced apart from the discharge unit at stroke of the piston during a second period after the collision of the piston.

A refrigerator according to an embodiment of the present invention includes: a compressor configured to compress a refrigerant; and an inverter module configured to control the compressor, wherein the inverter module includes: a heatsink provided with a cooling passage through which coolant passes; a coolant inlet connected to the heatsink to communicate with an inlet of the cooling passage; a coolant outlet connected to the heatsink to communicate with an outlet of the cooling passage; at least one insulated gate bipolar transistor (IGBT) disposed on a top surface of the heatsink; and at least one diode disposed to be spaced apart from the IGBT on the top surface of the heatsink, wherein the cooling passage includes: an IGBT cooling passage that is closer to the coolant inlet among the coolant inlet and the coolant outlet; and a diode cooling passage that is closer to the coolant outlet among the coolant inlet and the coolant outlet, wherein the diode cooling passage is disposed behind the IGBT cooling passage in a flow direction of the coolant.

An object of the present invention is to maintain a heating amount constant when a compressor is heated at the time of shutdown of the compressor, regardless of the influences of production tolerance and environment variations. An inverter control unit causes an inverter to generate a high-frequency AC voltage having a de-energized section in which a voltage applied from the inverter to a motor is zero between a section in which the voltage is positive and a section in which the voltage is negative. At this time, the inverter control unit detects a value of a current flowing to the inverter in a detection section residing from immediately before a start of the de-energized section to immediately after an end of the de-energized section, and causes the inverter to generate a high-frequency AC voltage adjusted according to the detected current value.

An air-conditioning system capable of suppressing power consumption and maintaining the indoor temperature at a constant level includes a refrigerant circuit in which a compressor, a heat source-side heat exchanger, an expansion device, and a load-side heat exchanger are sequentially connected via a pipe, an inverter that drives the compressor, an indoor temperature sensor that detects an indoor temperature, and a controller that receives a thermostat ON signal and a thermostat OFF signal and controls the inverter according to the thermostat ON signal and the thermostat OFF signal. The controller assumes, upon receipt of the thermostat OFF signal, that the indoor temperature detected at that time is a target temperature, and regulates an output frequency of the inverter so as to maintain a difference between the indoor temperature and the target temperature in a predetermined range.

An inverter control device that controls an inverter unit that converts a DC voltage from a converter unit to an AC voltage and supplies the AC voltage to the DC motor includes a storage unit that stores therein information regarding a synchronization-loss limit; a synchronization-loss limit-current calculation unit that calculates the limitation value on the synchronization-loss limit current on the basis of the magnet temperature of the DC motor, the bus voltage to be applied to the inverter unit, and the information regarding a synchronization-loss limit; and a control unit that compares the primary current to be input to the converter unit with the limitation value and that, when the primary current exceeds the limitation value, outputs an adjustment command to adjust the operating frequency of the DC motor such that the primary current becomes equal to or less than the limitation value.

An inverter unit (100) includes an inverter (110), an inverter housing (120) and an insulating member (130). The inverter (110) drives an electric motor (200) and includes at least one power module (112) for converting a High Voltage (HV) Direct Current (DC) to a three-phase Alternating Current (AC) that drives the electric motor (200). The inverter housing (120) receives the inverter (110). The power module (112) is mounted on an end wall (120a) of the inverter housing (120) by means of bolts (114). The insulating member (130) corresponding to each bolt (114) is disposed between a head portion (114a) of the corresponding bolt (114) and the power module (112).

In a motor driving apparatus including an inverter connectable to n motors (n being an integer not less than 2) each including a rotor having a permanent magnet, braking operation is performed on i (i being an integer from 1 to n−1) of the n motors, and then braking operation is performed on j (j being an integer from 1 to n−i) of the n motors other than the i motors. It is possible to reduce the risks of failure of the inverter and demagnetization of the motors due to overcurrent by reducing current flowing through the inverter and the motors when the braking operation is performed.

A refrigeration cycle apparatus includes a compressor, a condenser, a first subcooling device that subcools a refrigerant by exchanging heat with the air, a second subcooling device that performs a heat exchange between refrigerant streams that have been branched by a branch pipe, thereby subcooling one of the refrigerant streams, a flow control device that adjusts a flow rate of the second stream of the refrigerant and passes this refrigerant through the second subcooling device, a bypass path that allows the refrigerant passing through the flow control device and the second subcooling device to flow therethrough, an expansion valve, an evaporator, and a controller configured to control an amount of heat exchanged in the first subcooling device and an amount of heat exchanged in the second subcooling device based on a temperature of the air.

There is provided a vehicle air conditioning apparatus that can prevent the amount of the refrigerant discharged from the compressor from reducing when an outside air temperature is low to achieve a heating performance required for a heating operation, and also can dehumidify the vehicle interior without deteriorating the heating performance during a heating and dehumidifying operation. The vehicle air conditioning apparatus includes: a heat released refrigerant expansion valve that decompresses the refrigerant discharged from the radiator during the heating operation and the first heating and dehumidifying operation; a gas-liquid separator that separates the refrigerant decompressed by the heat released refrigerant expansion valve into a gaseous refrigerant and a liquid refrigerant; and a bypass circuit that allows part of at least the gaseous refrigerant separated in the gas-liquid separator to flow into a section of the compressor through which the refrigerant being decompressed passes.