A multi-unit transport refrigeration system including: a first transportation refrigeration unit configured to refrigerate a first transport container; a second transportation refrigeration unit configured to refrigerate a second transport container; and an energy management system including: an energy storage device configured to store electricity to power the first second transportation refrigeration unit; and a power conversion system electrically connecting the energy storage device to the first transportation refrigeration unit and the second transportation refrigeration unit, the power conversion system including: a first DC/DC converter configured to increase a voltage of the electricity received from the energy storage device from a first voltage to a second voltage; and a first DC/AC inverter configured to convert the electricity received from the first DC/DC converter from DC to AC and then convey the electricity to at least one of the first transportation refrigeration unit or the second transportation refrigeration unit.

A screw compressor includes a screw rotor, a gate rotor, and a speed adjuster. The screw rotor has an outer peripheral surface with a plurality of screw grooves. The screw rotor is configured to be rotated. The gate rotor has a plurality of teeth. A ratio T/S of a number T of the teeth to a total number S of the screw grooves is greater than or equal to 2.5. The gate rotor meshes with the screw rotor. The speed adjuster is configured to adjust a rotational speed of the screw rotor. Rotation of the screw rotor at an angle greater than 180° allows the screw compressor to perform a stroke from start of compression to completion of discharge.

Unique apparatuses, methods, and systems of opposing, limiting, and/or preventing undesired or un-commanded compressor rotation are disclosed. One exemplary embodiment is an HVACR system comprising a variable frequency drive configured to drive an electric motor to rotate a screw compressor or scroll compressor. A controller is configured to monitor various aspects of the system and to control the drive. When a condition indicative of potential undesired or un-commanded compressor rotation is identified, the controller commands the variable frequency drive to control the motor to limit and preferably prevent compressor rotation. One technique comprises shorting switches of the drive to a DC bus rail to allow back EMF induced current in the motor windings to be dissipated through winding resistance thus providing a damping force. Another technique comprises controlling the inverter to insert a DC current into the motor to cause the motor to align to and hold a particular position.

A method of controlling an air conditioner including activating a refrigeration cycle by driving an compressor; detecting a high pressure and a low pressure when the refrigeration cycle is activated; adjusting an operating frequency of the compressor based on the detected high pressure or low pressure of the refrigeration cycle; determining a current load of an inside space through a load detecting unit; determining a load level of the inside space by comparing the current load with a reference load; and determining the operating frequency of the compressor based on the determined load level.

A DC-powered system may include controls configured to switch between available DC power supplies and manage the refrigeration system in accordance with one or more methods. The one or more methods of the control system may include multiple tiers of power management, including, e.g., maximization of power usage when on a photovoltaic power supply to subcool a refrigerated load.

A power management method used for power distribution in a transportation refrigeration unit. The power management method includes calculating engine power according to engine operating parameters; calculating power generator real-time input power according to power generator excitation current; calculating available power based on the power generator real-time input power and the engine power; and managing power distributed to a compressor based on the available power. The present invention further relates to a power management system. The power management method and system have the advantages of simplicity, reliability, stable operation and the like, the power generator real-time input power can be calculated according to the power generator excitation current, thus more power can be provided to the compressor on the premise that the power supply to power generator loads is guaranteed, and the operating efficiency of the transportation refrigeration unit is improved.

A refrigerator and a method for controlling the same are disclosed. The refrigerator may minimize the size and material cost of the control system by controlling the internal temperature and the speed of a compressor using a thermostat used in the conventional low-capacity/low-cost refrigerator without using a system controller equipped with various sensors (internal sensors and/or external sensors) capable of controlling the internal temperature. In addition, since an inverter controller capable of controlling a BLDC compressor estimates the internal/external temperature based on operation information of the compressor, and determines the internal load, it may save energy and reduce vibrations and noise, which are the largest disadvantages of a constant-speed compressor, thereby improving satisfaction of the consumer. In addition, the BLDC compressor may be started and operated stably by applying a differentiated algorithm of the inverter controller.

Embodiments of the present disclosure relate to refrigerators and methods of controlling the refrigerators. The refrigerator comprises a compressor configured to operate at a first rotation speed and a controller configured to calculate a first average of levels of electric signals input to the compressor during a first reference period, and control the compressor to operate at a second rotation speed higher than the first rotation speed when the first average is greater than a first reference value.

Disclosed is a driver IC circuit of an intelligent power module including an upper bridge control signal input end, a lower bridge control signal input end, a PFC control signal input end, a logic input buffer circuit, a first upper bridge driver circuit, a second upper bridge driver circuit, a first lower bridge driver circuit, a second lower bridge driver circuit and a PFC driver circuit. The logic input buffer circuit performs full-wave filtering on control signals. The first upper bridge driver circuit, the first lower bridge driver circuit, the second upper bridge driver circuit and the second lower bridge driver circuit each drives a switch transistor corresponding to a first or second external motor according to one of the control signals. The PFC driver circuit drives an external PFC switch transistor according to one of the control signals. An intelligent power module and an air conditioner are also disclosed.

It is determined whether thermo-off postponement control is allowed or not on the basis of a current compressor operating frequency when a thermo-off condition is satisfied. If it is determined that thermo-off postponement control is allowed, the thermo-off postponement control in which a lowest operating frequency in an operating frequency range of a compressor is temporarily reduced within a range greater than or equal to a minimum operating frequency of the compressor in use so as to continue an operation. If it is determined that thermo-off postponement control is not allowed, thermo-off of stopping the compressor is performed.