A method for starting and stopping an asynchronous motor by way of a soft starter. The method includes the following steps: determining ignition options of one or more thyristors of the soft starter that are possible at a future calculation time; predicting the motor behavior for the determined ignition options, if an ignition of one or more thyristors of the soft starter is carried out; based on the predicted motor behavior, deciding whether an ignition option is to be selected and which is to be selected; and generating one or more ignition signals for one or more thyristors, if the decision for an ignition option has been made.

Solar Motor Controller is an electronic device with DC power input terminals that may connect directly to solar PV panels, and output terminals that may connect directly to single or multiphase phase AC electric motors without requiring an energy storage subsystem. The Controller runs electric motors of many frequencies and is capable of interfacing to multiple voltages of solar PV panels with or without maximum power point tracking. The Controller may drive motors in water pumping, HVAC, refrigeration, compressors operation, blowers, machine tools, and many other applications; some controller applications may operate at motor speeds adjusted to conform to power available from attached solar panels.

Solar Motor Controller is an electronic device with DC power input terminals that may connect directly to solar PV panels, and output terminals that may connect directly to single or multiphase phase AC electric motors without requiring an energy storage subsystem. The Controller runs electric motors of many frequencies and is capable of interfacing to multiple voltages of solar PV panels with or without maximum power point tracking. The Controller may drive motors in water pumping, HVAC, refrigeration, compressors operation, blowers, machine tools, and many other applications; some controller applications may operate at motor speeds adjusted to conform to power available from attached solar panels.

Embodiments of the present disclosure relate to a method, apparatus for operating a conduction assembly, a start device, and a computer-readable medium. The conduction assembly is coupled between an AC power supply and an inductive load, and comprises a first switch device and a second switch device which are in anti-series connection, the first switch device comprises a first body diode in anti-parallel connection with the first switch device, and the second switch device comprises a second body diode in anti-parallel connection with the second switch device. The method comprises: conducting the conduction assembly at a first conduction angle in a first cycle; conducting the conduction assembly in a second cycle at a second conduction angle that is greater than the first conduction angle, wherein in the first cycle and second cycle, a turn-off timing of the first switch device or the second switch device in anti-parallel connection with the first body diode or second body diode having a conduction direction the same as a current direction is determined based on the current flowing through the conduction assembly. The method proposed here may reduce the power loss of the soft start circuit.

A system for speed regulation of an induction motor including an induction motor configured to be driven by a 3-phase alternating voltage (AC) signal. The system further includes an encoder configured to measure a shaft speed of the induction motor. Further, the system includes a variable frequency drive (VFD) device configured to generate the 3-phase AC signal to drive the induction motor. The system also includes a controller configured to generate a control voltage signal based on the measured shaft speed of the induction motor and a reference speed, the control voltage signal being input to the VFD device to control a frequency of the 3-phase AC signal.

Examples include a method for controlling a motor soft-starter for starting an electric motor on a three-phases electric network in order to compensate a misbalance between the windings of the electric motor due to a misbalance between the phases of the electric network.

The power conversion device may include: power conversion circuitry configured to perform a power conversion for outputting a driving power to an induction motor; and control circuitry. The control circuitry may be configured to: receive a master command phase from a master power conversion device; generate a voltage command having a command phase in a rotating coordinate system based on a torque target value, wherein a rotating magnetic field for driving a rotor of the induction motor is generated to rotate with the rotating coordinate system; calculate a rotation phase of the rotating coordinate system based on a command phase difference between the master command phase and the command phase to reduce the command phase difference; and control the power conversion circuitry to output the driving power to the induction motor, in synchronization with the master power conversion device, based on the rotation phase and the voltage command.

The power conversion device may include: power conversion circuitry configured to perform a power conversion for outputting a driving power to an induction motor; and control circuitry. The control circuitry may be configured to: receive a master command phase from a master power conversion device; generate a voltage command having a command phase in a rotating coordinate system based on a torque target value, wherein a rotating magnetic field for driving a rotor of the induction motor is generated to rotate with the rotating coordinate system; calculate a rotation phase of the rotating coordinate system based on a command phase difference between the master command phase and the command phase to reduce the command phase difference; and control the power conversion circuitry to output the driving power to the induction motor, in synchronization with the master power conversion device, based on the rotation phase and the voltage command.

A method for power conversion generally includes a step of generating a drive current in a first winding of an electromagnet in a motor mode. The electromagnet may be mounted spatially proximate a rotor and has a bifilar coil. The bifilar coil may have a pair of conductors that form the first winding and a second winding. The second winding may be spatially parallel to, spatially separated from, and electrically isolated from the first winding. The rotor may be rotatably mounted and has a plurality of permanent magnets. Further steps generally include rotating the rotor in response to the drive current, removing the drive current from the first winding in a generator mode and inducing a load current through the second winding to an electrical load in response to a torque applied to the rotor.

A multi-pulse transformer with multiple taps provides a constant magnitude voltage output to a variable speed chiller's compressor motor over a range of input voltages. The 3-phase transformer includes primary windings and a plurality of secondary windings. The secondary windings are electromagnetically coupled with the associated primary winding. The primary windings include taps for receiving multiple input AC voltages and the secondary windings have a single output terminal for supplying a predetermined output voltage which, after rectification produces a DC multi-pulse waveform for powering a DC link of a variable speed drive. Alternatively the 3-phase transformer includes multiple taps on the secondary windings. Each of the primary windings has a terminal for receiving an input AC voltage. The taps of the secondary windings provide an output voltage that is converted to a multi-pulse waveform for powering a DC link of a variable speed drive.