According to an embodiment of the present disclosure, an apparatus includes a transformer having a set of input terminals, a first set of output terminals, and a second set of output terminals. First and second rectifiers are coupled to the first and second sets of output terminals, respectively. The transformer is configured to transform three phase alternating current (AC) provided to the set of input terminals into first and second three phase AC outputs at the first and second sets of output terminals, respectively. The first three phase AC output is phase shifted from the second three phase AC output.

A wind farm side voltage source converter comprises a DC terminal for connection to a DC transmission link, an AC terminal for connection to a wind farm that includes at least one wind turbine, and a main controller. The main controller is configured to modify an active power demand (Pdemand) of the voltage source converter which is received from a higher level controller by introducing an artificial inertia factor and/or in response to a measured DC voltage (Vdc_msr) at the DC terminal.

In order to improve a method for selecting a frequency converter for a refrigerant compressor unit that includes a refrigerant compressor and an electric drive motor such that the frequency converter is selected in a manner for optimized use, it is proposed that a working state suitable for operation of the refrigerant compressor unit should be selected within an application field of an application graph of the refrigerant compressor, that an operating frequency for this selected working state should be selected, and that a working state operating current value that corresponds to the selected working state and the selected operating frequency should be determined from drive data, for operation of the refrigerant compressor unit.

A method for flying start control of a motor, a computer readable medium, and a power conversion system having an inverter and a controller configured by computer executable instructions in a memory to perform flying start of a rotating motor by field weakening control to control the motor responsive to the motor speed exceeding the rated speed or other non-zero threshold at startup of the power conversion system. The method includes measuring a motor speed of a motor, responsive to startup of a power conversion system, and performing a flying start operation using field weakening control to control the motor responsive to the motor speed exceeding a non-zero threshold at startup of the power conversion system.

A wind farm side voltage source converter comprises a DC terminal for connection to a DC transmission link, an AC terminal for connection to a wind farm that includes at least one wind turbine, and a main controller. The main controller is configured to modify an active power demand (P.sub.demand) of the voltage source converter which is received from a higher level controller by introducing an artificial inertia factor and/or in response to a measured DC voltage (V.sub.dc.sub._.sub.msr) at the DC terminal.

A motor drive device includes a rectifier unit that rectifies first AC power supplied from a commercial power supply, an inverter that generates second AC power and output the second AC power to a motor, and a control unit that controls the operation of the inverter such that pulsation according to the power state of a capacitor is superimposed on a drive pattern of the motor, to reduce a charge and discharge current of the capacitor. The control unit performs load pulsation compensation control to compensate for load pulsation, power supply pulsation compensation control to reduce the charge and discharge current of the capacitor, and overload compensation control to reduce an inverter input current input to the inverter, while preferentially performing constant current load control to control the rotational speed of the motor.

According to an embodiment of the present disclosure, an apparatus includes a transformer having a set of input terminals, a first set of output terminals, and a second set of output terminals. First and second rectifiers are coupled to the first and second sets of output terminals, respectively. The transformer is configured to transform three phase alternating current (AC) provided to the set of input terminals into first and second three phase AC outputs at the first and second sets of output terminals, respectively. The first three phase AC output is phase shifted from the second three phase AC output.

A motor power source regulation circuit, a control method and an electronic device are provided. The motor power source regulation circuit includes a power factor correction circuit, an isolation circuit, a first power source conversion circuit, a second power source conversion circuit and a control circuit. The isolation circuit includes a first switch sub-circuit and an isolation transformer. The power factor correction circuit regulates an AC input signal to a first DC signal. The first switch sub-circuit converts the first DC signal to a first AC signal. The isolation transformer converts the first AC signal to two or more second AC signals. The first power source conversion circuit converts the second AC signal to a DC drive signal and outputs it to a DC motor. The second power source conversion circuit converts the second AC signal to an AC drive signal and outputs it to an AC motor.

According to an embodiment of the present disclosure, an apparatus includes a transformer having a set of input terminals, a first set of output terminals, and a second set of output terminals. First and second rectifiers are coupled to the first and second sets of output terminals, respectively. The transformer is configured to transform three phase alternating current (AC) provided to the set of input terminals into first and second three phase AC outputs at the first and second sets of output terminals, respectively. The first three phase AC output is phase shifted from the second three phase AC output.