System and method for monitoring and detecting potential problems early in a VCC based HVAC&R system employs a monitoring application or agent that uses continuous machine learning and a temperature map to derive or “learn” a relation between a measured input power parameter of one or more system compressors, and condenser and evaporator intake fluid temperatures, based on observations of the temperatures and the input power parameter when the HVAC&R system is new or in a “newly maintained” condition. The monitoring agent can then use the learned relation to determine, based on subsequent observations of the condenser and evaporator intake fluid temperatures, the input power parameter values that should be expected if the HVAC&R system were operating in the “newly maintained” condition. The agent can thereafter compare the expected compressor input power parameter values with observed input power parameter values to determine early whether the system is experiencing performance degradation.

The invention provides an air-conditioner for maintaining a temperature of a conditioned space at or near a set temperature. The air-conditioner comprises at least one rotating or reciprocating element adapted to rotate or reciprocate at a variable frequency. The variable frequency including one or more nuisance frequencies at which vibration or noise within the air-conditioner or the conditioned space causes a nuisance. A processor programmed to control variation of the variable frequency in response to operational requirement. The processor is configured to operate the at least one rotating or reciprocating element so as to substantially exclude operation at the one or more nuisance frequencies.

A driving device is used with a compressor including a motor including coils. The driving device drives the motor. The driving device includes an inverter connected to the coils, a connection switching unit to switch a connection state of the coils between a first connection state and a second connection state, a controller to control the inverter and the connection switching unit, and a compressor state detection unit to detect a state of the compressor. When the connection state of the coils is the first connection state, the controller controls the motor based on a first detection value detected by the compressor state detection unit and a first threshold. When the connection state of the coils is the second connection state, the controller controls the motor based on a second detection value detected by the compressor state detection unit and a second threshold.

An outdoor unit includes at least one heat exchanger, a first motor including a first fan, a second motor including a second fan, an inverter that applies voltage to the first motor and the second for respectively, a connection switching unit that switches the voltage applied to the second motor between on and off, and a control unit that controls the inverter and the connection switching unit. The inverter is disposed closer to the first motor than to the second motor.

An electric motor system is described. The electric motor system includes a drive circuit including an inverter configured to supply variable frequency current and a contactor configured to supply line frequency current. The electric motor system also includes an electric motor coupled to the drive circuit wherein the electric motor is communicatively coupled to a controller. The controller is configured to control the inverter to supply variable frequency current to the electric motor, thereby operating the electric motor at a motor speed, and determine, based upon at least one input parameter, a maximum potential motor speed the inverter can achieve. The controller is also configured to receive a command to operate the electric motor at line frequency current and control the drive circuit to transition from supplying variable frequency current to supplying line frequency current before the maximum potential motor speed the inverter can achieve is reached.

A heat pump system and a control method therefor. The heat pump system includes a compressor; an indoor heal exchanger; an outdoor heat exchanger, including a first heat exchange portion and a second heat exchange portion, wherein a flow path switching device is provided between the first heat exchange portion and the second heat exchange portion to disconnect or communicate the first heat exchange portion and the second heat exchange portion; a first four-way valve; and a second four-way valve, configured to enable a high-temperature refrigerant to be input into the first heat exchange portion in a heating mode, so as to enable the heat pump system to operate in a heating and deicing mode.

A cooling system is designed to generally allow for one or more compressors to be bypassed when ambient temperatures are low. The system includes a bypass line and valve that opens when ambient temperatures are low and/or when the pressure of the refrigerant in the system is low. In this manner, the refrigerant can flow through the bypass line instead of through one or more compressors. These compressors may then be shut off. To supply any needed pressure to cycle the refrigerant, the system may include a pump that turns on when the bypass line is open. When ambient temperatures are extremely low, thermosiphon may be used to cycle the refrigerant.

A method and system for improving energy efficiency of a refrigeration system include system components such as a condenser, one or more expansion valves, an evaporator, one or more compressors, and a system controller electrically coupled to the one or more of the system components, according to one embodiment. The system controller is configured to selectively actuate, directly or indirectly, the one or more expansion valves, the condenser, and/or the one or more compressors, at least partially based on temperatures and/or pressures of the system fluid at various points of the system, to control a temperature of a refrigerated area.

An air conditioning system including a compressor having a motor; a condenser; an evaporator; a drive providing multiphase, AC output to the motor; a motor braking assembly electrically connected to the drive, the motor braking assembly including at least one switch and at least one braking resistor; wherein the at least one switch is held in an open state by power from the drive; wherein upon disruption of power to the motor, the at least one switch assumes a closed state shorting windings of the motor through the at least one braking resistor.

A cryocooler includes a cold head, a plurality of compressor main bodies that are connected to the cold head in parallel, a plurality of state detection sensors that are provided to correspond to the plurality of compressor main bodies respectively and each detect a state of a corresponding compressor main body to output a state detection signal, and a compressor control unit that is configured to, in a case where the state detection signal from any one state detection sensor of the plurality of state detection sensors indicates that the corresponding compressor main body is stopped, stop also the other compressor main bodies.