A refrigeration system for a temperature-controlled storage device includes a refrigeration circuit, a cooling circuit, and a controller. The refrigeration circuit includes a compressor driven by a brushless DC motor operable at multiple different speeds, a first heat exchanger, an expansion device, and a cooling unit in fluid communication via a first working fluid. The cooling circuit includes a pump and a second heat exchanger in fluid communication with the first heat exchanger via a second working fluid such that the first heat exchanger is liquid-cooled by the second working fluid. The controller operates the brushless DC motor at multiple different speeds to accommodate multiple different thermal loads experienced by the refrigeration system. Each of the speeds corresponds to a different thermal load. The controller modulates the speed of the brushless DC motor to maintain a desired temperature of a temperature-controlled space within the temperature-controlled device.

In order to restrain damage of a component due to rush current, a main relay in a power source circuit is not turned on and does not conduct a power source line even when a heat source microcomputer is activated with a capacitor not sufficiently charged. This configuration avoids start of charging the capacitor without current limitation, to restrain damage of the component due to rush current.

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.

A motor driving device that is a device for driving a motor including stator windings, includes: a connection switching unit that includes relays as mechanical switches connected to the stator windings and excitation coils opening or closing the relays by being energized or non-energized with excitation current and switches connection condition of the stator windings to either of first connection condition (star connection) and second connection condition (delta connection) different from the first connection condition by opening or closing the relays; and an inverter that supplies AC drive voltages to the stator windings.

A control method and a control system for a compressor in a refrigeration system, implements control logic based on the monitoring of parameters of the refrigeration system, where these parameters may include, for example, a previous load (C.sub.ant), a current load (C.sub.atu), a reference load (C.sub.ref), a measured cycle time (t.sub.cycle) and a target time (t.sub.target).

A heating, ventilation, air conditioning, and/or refrigeration (HVAC&R) system includes a refrigerant loop having a compressor configured to circulate a refrigerant therethrough, a motor configured to drive rotation of the compressor, wherein the motor is a permanent magnet assisted synchronous reluctance (PMASR) motor, and a motor cooling system configured to direct a portion of the refrigerant from the refrigerant loop and through a housing of the PMASR motor to place the portion of the refrigerant in thermal communication with components of the PMASR motor.

The present invention quickly stops rotation of an electric compressor while preventing damage to switching elements. An electric compressor 1 comprises a motor drive circuit 52 having multiple switching elements IGBT Q1 to Q6, a control unit 53 that controls driving of the multiple switching elements IGBT Q1 to Q6 and drives a motor 4, and a current detection unit 54 that detects a current flowing through the motor drive circuit 52. The control unit 53 performs stop control that stops rotation of the compression mechanism 3 by performing braking control that controls drive of predetermined switching elements IGBT (Q2, Q4, Q6 and the like) among the multiple switching elements IGBT Q1 to Q6. In the brake control, when the detected current value I is lower than the first threshold I.sub.1, the control unit 53 adjusts the drive pattern of the predetermined switching elements IGBT (Q2, Q4, Q6 and the like) in order to prevent the detected current value I from exceeding the second threshold I.sub.2 that is lower than the first threshold I.sub.1.

A recreational vehicle air conditioning system supports multiple recreational vehicle air conditioning units having closed air conditioning circuits and a controller that is electronically coupled to each of the recreational vehicle air conditioning units to control each of the closed air conditioning circuits to regulate an overall power consumption of the multiple recreational vehicle air conditioning units. A recreational vehicle air conditioning system may also support multiple recreational vehicle air conditioning units where a refrigerant line set is coupled between the recreational vehicle air conditioning units such that a compressor in one of the recreational vehicle air conditioning units is capable of supplying refrigerant to the evaporators of the multiple recreational vehicle air conditioning units, and such that valves coupled in series with each of the evaporators may be regulated to control cooling by each recreational vehicle air conditioning unit.

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.

An inverter-converter system includes a DC source, a DC to DC boost converter, a DC link capacitor, an inverter circuit, a variable speed electric machine, and a controller. The DC to DC boost converter receives an input DC voltage from the DC source. The inverter circuit converts the variable boosted voltage to an AC voltage to drive the variable speed electric machine. The controller senses a plurality of parameters from the variable speed electric machine, and controls the DC to DC boost converter to boost up the input DC voltage to a variable output voltage based on the plurality of parameters and/or the voltage (or load) needed by the variable speed electric machine. The design of the inverter-converter system can achieve an electrical efficiency and cost savings for the overall system.