Embodiments of the present disclosure relate to a refrigeration system that includes a compressor configured to circulate refrigerant along a refrigerant loop, a motor configured to drive the compressor, and a variable speed drive coupled to the motor and configured to supply power to the motor. The variable speed drive includes a primary winding of a step down transformer coupled to an alternating current (AC) power source, a first secondary winding of the step down transformer, where the first secondary winding is configured to supply power at a variable supplied voltage to the motor when the motor operates below a threshold voltage, and a second secondary winding of the step down transformer, where the second secondary winding is configured to supply power at a fixed supplied voltage when the motor operates at or above the threshold voltage.

A scroll compressor includes a rotor, a stator, a rotary shaft, an end bracket, an orbiting scroll, a fixed scroll, a suction type cooling fan, and a discharge brush. The discharge brush is fixed to the end bracket facing the cooling fan by a fixing member attached in a radial direction relative to the rotary shaft, and one end of which is in contact with the rotary shaft, in a space secured by the clearance.

A method for controlling a permanent magnet (PM) synchronous motor in an ESP application is provided. A load angle of the PM motor is estimated. A voltage adjustment value is determined for the PM motor based at least on the estimated load angle of the PM motor. A voltage to be applied to the PM motor is determined based on the voltage adjustment value.

A method for controlling a permanent magnet (PM) synchronous motor in an ESP application is provided. A load angle of the PM motor is estimated. A voltage adjustment value is determined for the PM motor based at least on the estimated load angle of the PM motor. A voltage to be applied to the PM motor is determined based on the voltage adjustment value.

Embodiments of the present disclosure relate to a refrigeration system that includes a compressor configured to circulate refrigerant along a refrigerant loop, a motor configured to drive the compressor, and a variable speed drive coupled to the motor and configured to supply power to the motor. The variable speed drive includes a primary winding of a step down transformer coupled to an alternating current (AC) power source, a first secondary winding of the step down transformer, where the first secondary winding is configured to supply power at a variable supplied voltage to the motor when the motor operates below a threshold voltage, and a second secondary winding of the step down transformer, where the second secondary winding is configured to supply power at a fixed supplied voltage when the motor operates at or above the threshold voltage.

A method for controlling a permanent magnet (PM) synchronous motor in an ESP application is provided. A load angle of the PM motor is estimated. A voltage adjustment value is determined for the PM motor based at least on the estimated load angle of the PM motor. A voltage to be applied to the PM motor is determined based on the voltage adjustment value.

To improve the accuracy of detecting a current flowing through an electric compressor after operation of the electric compressor, the electric compressor having a large change in temperature before and after operation. An inverter-integrated electric compressor (1) that compresses and discharges a refrigerant suctioned therein, includes an inverter device (2) provided with a circuit board (60) mounted with an inverter circuit (40), the inverter device (2) being integrally incorporated in an inverter case. The circuit board (60) is provided with a current detection circuit (30) that detects an input current flowing through the inverter circuit (40), and an offset correction circuit (20). The current detection circuit (30) includes a shunt resistor (32) that is serially connected to the inverter circuit (40) and detects a current, and a first amplifier (31) that amplifies and outputs a voltage appearing as a voltage drop in the shunt resistor (32). The offset correction circuit (20) includes a second amplifier (21) that performs an offset correction of the first amplifier (31). The first amplifier (31) and the second amplifier (21) are integrated into a single integrated circuit.

Provided is a scroll compressor capable of reducing a shaft voltage and achieving space savings for the entire apparatus. A scroll compressor 100 includes a rotor 32 that is stored in a motor casing 14; a stator 31 that is stored in the motor casing 14, and drives the rotor 32 to rotate; a rotary shaft 12 that is held by bearings 33 and 34, and rotates integrally with the rotor 32; an end bracket 16 through which one end portion of the rotary shaft 12 passes, and which seals the motor casing 14; an orbiting scroll 44 that supports the other end portion of the rotary shaft 12, and orbits as the rotary shaft 12 rotates; a fixed scroll 43 that is disposed facing the orbiting scroll 44; a suction type cooling fan 13 which is fixed to one end portion of the rotary shaft 12 while being apart by a clearance from the end bracket 16, and which suctions outside air through a suction port provided in an end surface 132A of a fan cover 132, and generates cooling wind for cooling the fixed scroll 43 or the orbiting scroll 44 in the fan cover 132, as a rotary vane 131 accommodated in the fan cover 132 rotates; and a discharge brush 60 which is fixed to the end bracket 16 facing the cooling fan 13, and one end of which is in contact with the rotary shaft 12.

The present application discloses a fuel system for a gas turbine engine. The engine includes a main alternating current electrical generator driven by an engine shaft such that the electrical output frequency of the electrical generator varies in dependence on shaft rotational speed. The fuel system includes a variable flow fuel pump for providing a fuel flow to the engine, a frequency and/or voltage controller configured to provide electrical power having at least one of a predetermined output frequency and a predetermined voltage, and a variable speed electric motor configured to drive the fuel pump. The electric motor includes an induction motor having a stator and at least a first rotor, the stator having first and second sets of stator windings. Each set of stator windings is configured to impart a torque on the rotor in use.

To improve the accuracy of detecting a current flowing through an electric compressor after operation of the electric compressor, the electric compressor having a large change in temperature before and after operation. An inverter-integrated electric compressor (1) that compresses and discharges a refrigerant suctioned therein, includes an inverter device (2) provided with a circuit board (60) mounted with an inverter circuit (40), the inverter device (2) being integrally incorporated in an inverter case. The circuit board (60) is provided with a current detection circuit (30) that detects an input current flowing through the inverter circuit (40), and an offset correction circuit (20). The current detection circuit (30) includes a shunt resistor (32) that is serially connected to the inverter circuit (40) and detects a current, and a first amplifier (31) that amplifies and outputs a voltage appearing as a voltage drop in the shunt resistor (32). The offset correction circuit (20) includes a second amplifier (21) that performs an offset correction of the first amplifier (31). The first amplifier (31) and the second amplifier (21) are integrated into a single integrated circuit.