A method for controlling an electronic switching unit for supplying electric power to an inductive power load, includes the following steps: activating an initial filter capacitor by connecting it between the electric power supply of the electronic unit and ground, and deactivating the other capacitors of the bank of filter capacitors; measuring the current flowing through this initial filter capacitor; if this current is above a predetermined nominal current threshold, activating an additional filter capacitor by connecting it between the electric power supply of the electronic unit and ground, in parallel with the initial filter capacitor.

A method and system of subsynchronous oscillations and interactions damping integrated in in a rotor converter based on an adaptive state feedback controller with two spinning vectors, and a Kalman filter whose parameters are optimized by minimizing maximum sensitivity under a constraint of positive damping for a plurality of sensible scenarios is provided. The damping signal generated by the damping module is applied either to a power proportional integer controller or to a current proportional integer controller.

Provided is a power conversion controller in which variation in reactive power among power conversion controllers can be inhibited while maintaining the running performance of vehicles. The power conversion controller includes a power factor setter that sets a power factor based on a detection value of an overhead line voltage, and a calculator that calculates a reactive current command value by multiplying an active current command value by a tangent of a power factor angle of the power factor. The power factor setter sets a reference value set in advance as the power factor if the detection value is within a reference range, sets a value smaller than the reference value as the power factor if the detection value is below the reference range, and sets a value larger than the reference value as the power factor if the detection value is beyond the reference range.

The invention relates to an energy efficient induction motor (100) comprising a stator (102), a main winding (M) of the stator (102) for generating a rotating magnetic field (RMF) (108), and a rotor (104) disposed to rotate relative to the main winding (M) of the stator (102) due to the RMF (108). The stator (102) comprises additional winding(s) (A) for producing an alternating EMF (110) which is induced in the one or more additional windings (A) due to the rotation of the rotor (104). The alternating EMF (110) produced in the one or more additional windings (A) is fed back simultaneously to the main winding (M) of the stator (102) throughout the complete rotation cycle of the rotor (104) through an electronic control unit (112) coupled to the stator (102), producing a resultant AC output power (116) that is fed continuously to the main winding (M) of the stator (102).

An electric motor drive apparatus comprising a voltage converter component arranged to receive a supply voltage signal and output a bus voltage signal, and a motor driver component arranged to receive the bus voltage signal and generate at least one drive signal for an electric motor from the bus voltage signal. The motor driver component is arranged to output a bus voltage feedback signal to the voltage converter component. The voltage converter component is arranged to regulate a voltage level of the bus voltage signal based at least partly on the bus voltage feedback signal output by the motor driver component.

In a power converter, a first single-phase AC conversion unit, which is connected to a first line of a first phase and a second line of a second phase of a first three-phase AC, a second single-phase AC conversion unit, which is connected to the second line of the second phase and a third line of a third phase of the first three-phase AC, and a third single-phase AC conversion unit, which is connected to the third line of the third phase and the first line of the first phase of the first three-phase AC, form a delta-connected load for an AC power supply system. At least the first single-phase AC conversion unit, the second single-phase AC conversion unit, and the third single-phase AC conversion unit form a first set in which respective output terminals are connected in series to one another, and the first set, and a second set and a third set, which are different from the first set, form each phase of a star connected power supply. A reactive power control unit controls a reactive power of a converter of each single-phase AC conversion unit based on a reactive power command value generated based on an acquired value related to an active power.

The present disclosure is constructed on the prior art inverter architecture, a pulse code width modulation (PCWM). This is an open loop motor control system without sensing its rotor position. The present disclosure employs a closed loop method to track the optimum efficiency motor operating point directly. A bench load test is conducted to gather information for an AI type control, which includes both load angle vs. voltage command charts and power factor vs. voltage command charts, with load levels as parameters for certain frequency command ranges. This way, the optimum efficiency motor operating points are generated a priori. The AI type control is mechanized to track the optimum efficiency motor operating points.

An electric motor assembly includes a stator, a rotor, a motor housing, a rotatable shaft, a radial fan, and an air scoop. The motor housing at least partly houses the stator and rotor and presents an exterior motor surface. The rotatable shaft is associated with the rotor for rotational movement therewith, with the rotatable shaft extending along a rotational axis. The radial fan is mounted on the rotatable shaft exteriorly of the motor housing and is rotatable with the shaft to direct airflow in a radially outward direction. The air scoop extends radially outwardly relative to the radial fan and axially to receive radial airflow from the radial fan and turn the airflow axially to flow along the exterior motor surface. The air scoop includes spaced apart axially extending airflow vanes to guide the airflow as the airflow is turned axially.

A direct-current power supply apparatus includes: a reactor having one end connected to an alternating-current power supply; a bridge circuit, connected to an opposite end of the reactor, converting an alternating-current first voltage output from the alternating-current power supply into a direct-current voltage; and a current detector detecting an alternating current flowing between the alternating-current power supply and the bridge circuit. The reactor reduces an inductance in accordance with an increase of the alternating current and, when the alternating current exceeds a first current, has an inductance lower than one third of an inductance at which a current does not flow in the reactor. The bridge circuit performs an active operation when the detection value of the alternating current is larger than or equal to the first current and performs a passive operation when the detection value of the alternating current is lower than the first current.

A power converting apparatus includes: a reactor that includes a first terminal and a second terminal, the first terminal being connected to an alternating-current power supply; a bridge circuit that is connected to the second terminal of the reactor, includes at least one or more switching elements, and converts an alternating-current voltage output from the alternating-current power supply into a direct-current voltage; a power-supply current detecting unit that detects a current from the alternating-current power supply; and a control unit that controls ON and OFF of the switching elements depending on a current value detected by the power-supply current detecting unit, in which two or more current thresholds for controlling ON and OFF of the switching elements are included.