An abnormality determination device (60) includes a calculator (66) calculating a deviation degree of a compressor (11) from a normal state based on data related to operation of a refrigeration apparatus (1) and a determination unit (62) determining whether the compressor (11) has an abnormality or estimating an abnormality occurrence time based on a calculation result of the calculator (66). The calculator (66) calculates a first index value from data related to operation of the refrigeration apparatus (1) in a first period and a second index value from data related to operation of the refrigeration apparatus (1) in a second period that differs in length from the first period. The calculator (66) calculates the deviation degree of the compressor (11) from the normal state based on the first index value and the second index value. The determination unit (62) determines whether the compressor (11) has an abnormality or estimates an abnormality occurrence time based on the deviation degree of the compressor (11) from the normal state.

An air conditioning system and a method for controlling the same are provided. The air conditioning system includes an enhanced vapor injection compressor, first and second direction switching assemblies, first and second heat exchangers and a flash evaporator. The enhanced vapor injection compressor has an air discharge port, an air supplement port, first and second air suction ports, and an air return port. Pressure in a sliding vane chamber of an air cylinder corresponding to the second air suction port is equal to a discharge pressure at the air discharge port. A first pipe port of the first direction switching assembly is connected with the second air suction port, a second pipe port thereof is connected with the air discharge port and a third pipe port thereof is connected with the liquid accumulator, and the first pipe port is communicated with one of the second and third pipe ports.

A method of controlling an HVAC system including a motor having five taps, an HVAC controller connected to the motor, and a mobile device includes receiving user input identification of the motor on a user interface of the mobile device. A plurality of operating conditions and more than five speed settings available for the identified motor are displayed on the user interface. The method includes receiving from the user a selected speed of the speed settings for a first operating condition of the plurality of operating conditions, and transmitting the selected speed and the associated first operating condition to the HVAC controller for use in controlling a speed of the motor during the plurality of operating conditions.

A motor drive device: a power conversion unit; a current detection unit that detects a phase current of the alternating-current motor; a position/speed specifying unit that specifies a magnetic pole position and a rotational speed of the alternating-current motor; a d-axis current pulsation generating unit that generates a d-axis current pulsation command based on q-axis current pulsation or a q-axis current pulsation command, which being in synchronization with the q-axis current pulsation or the q-axis current pulsation command and preventing or reducing an increase or decrease in amplitude of the voltage command; and a dq-axis current control unit that generates the voltage command for controlling the phase current on the dq rotating coordinates, which rotate in synchronization with the magnetic pole position, by using the magnetic pole position, the rotational speed, the phase current, the q-axis current pulsation or the q-axis current pulsation command, and the d-axis current pulsation command.

The disclosure describes a system that includes an evaporator, an accumulator downstream of the evaporator, a centrifugal compressor downstream of the accumulator, a first heat exchanger stage downstream of the centrifugal compressor, and a second heat exchanger stage downstream of the first heat exchanger stage. The evaporator is configured to cool a conditioned air stream using a refrigerant. The accumulator is configured to store excess refrigerant. The centrifugal compressor is configured to compress the refrigerant. The first heat exchanger stage is configured to cool the refrigerant using environmental air. The second heat exchanger stage is configured to cool the refrigerant from the first heat exchanger stage using a portion of the excess refrigerant from the accumulator.

An apparatus and a method for detecting refrigerant leakage in an air source heat pump system. The method for detecting refrigerant leakage in an air source heat pump system includes the following steps in a cooling mode: S110: obtaining a running parameter of an air source heat pump system, wherein the running parameter at least includes a compressor rotational speed; S120: comparing the running parameter with a preset running parameter range; S130: updating a cumulative score when the running parameter falls within the preset running parameter range; and S140: when the cumulative score exceeds a predetermined cumulative score, determining that refrigerant leakage occurs, and when the cumulative score does not exceed the predetermined cumulative score, return to step S110.

The present disclosure relates to the field of air conditioning technology. In particular, it involves a control method and control system based on a variable speed AC compressor.

A chiller system may include a compressor configured to compress a refrigerant by rotation; a condenser configured to condense the refrigerant compressed by the compressor; an expander configured to expand the condensed refrigerant; an evaporator configured to evaporate the expanded refrigerant; a sensor unit including a plurality of temperature sensors, a speed sensor that senses a rotational speed of the compressor, and a current sensor that senses a current of the compressor; and a controller configured to determine whether to enter into a surge detection logic based on a volatility of data sensed by the sensor unit, and configured to perform surge detection.

In a refrigerant compressor for refrigeration plants, comprising a compressor unit driven by a drive unit, wherein at least one of these units is provided with a control unit which is controllable by means of a delivery rate control system in order to control the refrigerant compressor at different delivery rates, wherein an external delivery rate setpoint value is communicated to the delivery rate control system, in order to prevent critical operating states, it is proposed that the delivery rate control system acquires, by means of a sensor, a compressor reference temperature of the compressor unit, that the delivery rate control system ascertains an operating state value group for the acquisition of an operating state of the refrigerant compressor and, taking account of specified reference values, if the value of the ascertained operating state value group based upon the compressor reference temperature permits a critical operating state of the refrigerant compressor, specifies a delivery rate which has as its result an operation of the refrigerant compressor outside of the critical operating states.

A vapor compression system and method for operating the vapor compression system are provided. The vapor compression system includes a first compressor, a second compressor, a condenser, and at least one check valve disposed between the first compressor and the condenser. The method provides for the transmitting of a shutdown command to at least one of the first compressor and the second compressor, at least one of the first compressor and the second compressor including a rotating shaft and a magnetic bearing, the magnetic bearing having an active mode and an inactive mode, the magnetic bearing levitating the rotating shaft in the active mode. The method further provides for the monitoring of at least one of a rotational speed of the rotating shaft and a differential pressure over the check valve for a preset time, wherein the magnetic bearing remains in the active mode at least during the preset time.