The present disclosure relates to controls and related methods for mitigating liquid (e.g., compressor refrigerant, etc.) migration and/or floodback.

The technologies described and recited herein pertain to a permanent magnet motor having multiple voltage taps so that the motor may run in multiple configurations, e.g., a low-range and a high-range, and have multiple optimal operating points.

Methods are directed towards dynamically determining refrigerant film thickness at the rolling-element bearing and for dynamically controlling refrigerant film thickness at the rolling-element bearing. Further, an oil free chiller system is configured for dynamically determining refrigerant film thickness at the rolling-element bearing of the oil free chiller system, wherein the oil free chiller system is also configured for dynamically controlling refrigerant film thickness at the rolling-element bearing of the oil free chiller system.

A method initializes a defrosting operation in a refrigeration appliance having a speed-controlled compressor. The method includes the steps of: a) starting up the compressor at a speed set to an initial value, b) adjusting the speed of the compressor in order to prevent a temperature in a storage chamber of the refrigeration appliance from deviating from a target temperature, c) monitoring a deviation between an adjusted speed and the initial value, and d) deciding that defrosting is necessary if the deviation exceeds a limit value.

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.

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 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 thermal management system for an enclosure containing electrical components includes a cooling unit for controlling temperature inside the enclosure and a controller for the cooling unit, the controller being configured so that it can receive a three-phase power input signal and distribute power and control connected components using the three-phase signal. The controller can protect the compressor in critical scenarios such as thermal overload and overcurrent. The controller can output various faults such as missing phase alarm, imbalance phase alarm, overcurrent alarm, thermal overload alarm, door open alarm, and temperature and pressure alarms. An auto phase sequence correction controls the phase relay, accepting 3 phase 480 VAC power input from facility power terminal, supplying 3 phase power to the compressor and motor impellers, 12V DC power to a display unit, and 24V DC power to a remote access control module.

A server for a control system for cooling systems is disclosed. The server includes a memory device configured to store instructions and a processor communicatively coupled to the memory device and a plurality of cooling systems. Each of cooling systems includes a motor, a sensor, a local memory, and a microprocessor communicatively coupled to the motor, the sensor, the local memory. The microprocessor is configured to control operation of the motor according to settings defined by configuration data stored in the local memory. In response to reading the instructions, the processor is configured to receive, from the sensor of each of the cooling systems, first sensor data, generate first configuration data by executing a first algorithm on the first sensor data, and instruct the microprocessor of at least one cooling system to write the first configuration data to the local memory of the at least one cooling system.

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.