The auxiliary AC system includes a temperature measurement device configured to generate a variable output based on an air temperature in an environment proximate to the AC system and a compressor control circuit communicably coupled to a variable speed motor. The compressor control circuit is configured to receive the variable output from the temperature measurement device, determine that the output indicates a change in the air temperature, and generate a control signal for the variable speed motor, the control signal including a current having a magnitude depending on the extent of the change to vary a rate at which a compressor pressurizes a refrigerant vapor.

A compressor fault diagnostic apparatus including a current sensing unit to sense a current flowing through a motor of the compressor, a fault diagnostic unit to determine whether or not the motor performs a reverse rotation based on the current flowing through the motor, and a cut-off unit to remove power based on a determination of the fault diagnostic unit.

Systems and methods for monitoring an HVAC&R system employ a monitoring agent that uses observations of evaporator and condenser intake temperatures, evaporator discharge temperature, and a compressor input power parameter to learn operating characteristics of the HVAC&R system in newly maintained condition. Thereafter, the agent continuously or regularly computes a relative coefficient of performance (COP) for the system under subsequent observed ambient conditions, and relates the present instantaneous efficiency of the HVAC&R system under the observed ambient conditions to the instantaneous efficiency when the system was in newly maintained condition. The relative COP can be used to detect system degradation and quantify the energy usage and cost attributable to the degradation. The agent can take appropriate actions to prevent/minimize damage based on the degree of degradation detected, including shutting off power to the HVAC&R system. The monitoring agent can also be extended to other types of systems besides HVAC&R system.

A vehicle, a refrigerator for a vehicle, and a method for controlling a refrigerator for a vehicle are provided. The method for controlling the refrigerator for the vehicle includes turning on a switch of the refrigerator for the vehicle, measuring a temperature of an interior of the refrigerator for the vehicle a first time, measuring a temperature of the interior of the refrigerator for the vehicle again a second time after a predetermined time has elapsed from the first time, determining a temperature change of the interior of the refrigerator from the first time to the second time, and operating the refrigerator for the vehicle in a quench mode in which the temperature in the interior of the refrigerator is rapidly lowered, unlike a normal mode, if the temperature change in the interior of the refrigerator is in a positive direction.

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

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.

An HVAC system including a multi-capacity compressor, and a control system for the multi-capacity compressor are described herein. The control system includes an AC line voltage source, a variable-voltage variable-frequency drive, and a processor. The AC line voltage source is configured to operate the multi-capacity compressor. The variable-voltage variable-frequency drive is coupled to the AC line voltage source and is configured to operate the multi-capacity compressor at a variable speed. The processor is coupled to the AC line voltage source and the variable-voltage variable-frequency drive and is configured to selectively couple the AC line voltage source and the variable-voltage variable-frequency drive to the multi-capacity compressor to operate the multi-capacity compressor. The processor is further configured to transmit a capacity control signal to the multi-capacity compressor. The capacity control signal is instructive to operate the multi-capacity compressor in one of a plurality of capacity settings.

A motor driving device that drives a motor and is capable of switching a connection state of stator windings of the motor, includes: relays to switch the connection state of the stator windings by switching positions of contact plates; and a contact control unit to control each of the positions of the contact plates by outputting, to the relays, signals for actuating the contact plates. The contact control unit switches the connection state by sequentially switching output values of the signals such that the output values of the signals are switched at different timings from each other in the relays, and changes a switching order every time the connection state is switched, the switching order being an order in which the output values of the signals are switched.

A method for adjusting compression efficiency for an HVACR system having a variable-frequency drive (VFD) is disclosed. The method includes determining a first compression efficiency, determining an operating point, determining a region of an operating map when a difference between the operating point and a previously determined operating point exceeds a predetermined threshold, adjusting a VFD input to a first input based on the region of the operating map, and controlling the VFD using the first input for a predetermined period of time. The method also includes determining a second compression efficiency and an operation restriction, adjusting the VFD input to a second input based on the operation restriction and a difference between the first compression efficiency and the second compression efficiency, and controlling the VFD using the second input. The method also includes utilizing machine learning control techniques to control several system variables to optimize the compression efficiency.

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 variably frequency current to supplying line frequency current before the maximum potential motor speed the inverter can achieve is reached.