Systems, methods and apparatuses for monitoring the activity temperature controlled compartments of a refrigeration system by monitoring the activity of the compressor as the compressor changes between the ON or OFF state. In particular, the disclosure describes systems methods and tools for measuring the electrical loads drawn by the compressor for the purpose of predicting and determining the occurrence of unknown events from the energy profile of the compressors. One or more specialized computer systems may be connected between the compressor circuit and an energy source in order to monitor and track the amounts of energy being delivered to the compressor. The specialized computer systems measuring and tracking the electrical load supplied to the compressor may characterize the electrical load supplied as having one or more energy profiles. Each of the energy profiles may correspond to different types of events resulting in the consumption of energy by the compressor.

A condenser includes a shell having a vapor refrigerant inlet, a first tube bundle and a liquid refrigerant outlet. A second tube bundle is positioned in a subcooler component. The subcooler component has a center channel and at least two outer channels and conforms to the shell.

A system includes a compressor driven by a motor. A condenser receives working fluid from the compressor. An evaporator is in fluid communication with the condenser and the compressor. A first sensor produces a first signal indicative of one of current and power drawn by the motor. A second sensor produces a second signal indicative of a discharge line temperature. A processing circuitry processes the first signal and the second signal to determine a freeze time. The processing circuitry processes the freeze time, the current signal, and the discharge line temperature signal to determine a working fluid charge level.

A drive circuit includes a rectification circuit, a buck converter, and an inverter. the rectification circuit is configured to rectify a first AC voltage signal to generate a rectified voltage signal. The buck converter is configured to downconvert the rectified voltage signal to a DC voltage signal, wherein the DC voltage signal is supplied to a DC bus. The inverter is configured to convert the DC voltage signal to a second AC voltage signal and supply the second AC voltage signal to a compressor motor and to a condenser fan motor. The peak voltages of the second AC voltage signal are less than peak voltages of the first AC voltage signal.

Provided is an oil level detection device to be mounted on a refrigerating and air-conditioning apparatus, the oil level detection device being configured to detect an oil level of oil accumulated inside a compressor forming the refrigerating and air-conditioning apparatus. The oil level detection device includes an oil level detection unit installed on an outer surface of the compressor and configured to detect a temperature of an installation position, a sensor output unit configured to output, to the refrigerating and air-conditioning apparatus, a signal for changing an operation state of the refrigerating and air-conditioning apparatus, and a determination unit configured to determine depletion of the oil accumulated inside the compressor based on measurement values obtained by the oil level detection unit at least after an output of the signal to be output from the sensor output unit.

A method for operating a linear compressor includes measuring a current induced in a motor of the linear compressor and calculating an observed current of the motor of the linear compressor using at least an electrical dynamic model for the linear compressor and a robust integral of the sign of the error feedback. The method also includes detecting a head crash within the linear compressor if an error between the observed current of the motor of the linear compressor and the measured current induced in the motor of the linear compressor is greater than a crash threshold.

A domestic refrigeration device and a method for operating a domestic refrigeration device. The domestic refrigeration device has a heat-insulated body with a coolable inner container which delimits a coolable interior provided for storing food. A coolant circuit is provided for cooling the coolable interior and includes a compressor and a field-oriented electric drive. The field-oriented electric drive has a field-oriented controller, a converter, and a permanently excited synchronous motor which is connected downstream of the converter and which is part of the compressor or is provided for driving the compressor.

The invention relates to an electric compressor control device comprising a low-voltage domain. The low-voltage domain comprises a first control unit set up to process control commands for the control of the electric compressor, and a first voltage supply set up to supply the first control unit and connected to a low-voltage source. The low-voltage domain comprises furthermore a high-voltage domain. The high-voltage domain comprises a second control unit set up to control a power output stage, wherein the power output state inverts a dc voltage from a high-voltage source into an ac voltage in order to supply a motor of the electric compressor with the ac voltage. The high-voltage domain comprises furthermore a second voltage supply set up to supply the second control unit and connected to the high-voltage source.

A method is provided for detecting in real-time a refrigerant charge loss in a refrigerant vapor compression system. If both a sensed evaporator outlet superheat exceeds a target evaporator outlet superheat by at least a preset amount of superheat and a sensed degree of openness of an electronic expansion valve exceeds a preset degree of openness for a preset time of period, and a sensed air temperature of either a flow of supply air having traversed the evaporator or a flow of return air returning to the evaporator is changing at a rate less than preset air temperature rate of change, a service alarm is generated indicating a loss of charge warning.

The present application relates to air conditioning technology and motor control technology, and in particular to a motor drive system for a chiller unit, a chiller unit comprising the motor drive system, a control method for a chiller unit, and a computer-readable storage medium on which is stored a computer program for implementing the method. A motor drive system for a chiller unit according to an aspect of the present application comprising: a variable frequency drive unit configured to drive a first motor; a power frequency drive unit configured to drive a second motor; and a control unit configured to adapt a load demand of the chiller unit by controlling output power of the variable frequency drive unit and the power frequency drive unit.