Device for operating an electric motor, comprising a detection unit for detecting zero-crossings and phase angles of applied phase-shifted sinusoidal voltage phases of a multi-phase power supply network; and a switching unit for connecting half-waves of the applied sinusoidal voltage phases through by means of semiconductor switches in accordance with switching patterns applied to the semiconductor switches, said patterns being synchronised with the detected phase angles and zero-crossings, to generate phase-shifted quasi-sinusoidal voltage phases which are applied directly to the electric motor.

The present invention discloses an electric drive train comprising: a rotor or propeller shaft (R), an electric motor assembly (GEMD) configured to drive the rotor or propeller shaft (R), the electric motor assembly (GEMD) comprising a plurality of stacked electric motor elements (Ee1, Ee2, Ee3, Ee4), a power branch of a first topology feeding a stacked electric motor element (Ee1) of the electric motor assembly (GEMD), said power branch (b1) comprising a RESS and an electric generator (G) supplying a power signal to said power branch (b1), a power branch (b3) of a second topology dissimilar from the first topology, said power branch feeding another stacked electric motor element of the electric motor assembly (GEMD), said power branch (b3) comprising: # an electric generator (G) supplying a power signal to said power branch, a matrix converter (Mc3) feeding the another stacked electric motor element (Ee3), # or, an electric generator supplying Direct Current to said power branch and a motor controller feeding the second stacked electric motor element (Ee3).

The invention relates to a method for maintenance of a frequency converter for driving an electric motor of a transportation device, said frequency converter being supplied with AC mains power via a contactor, and including a rectifier circuit for providing a DC supply voltage, a capacitive intermediate circuit for leveling DC supply voltage, and an inverter circuit for providing power to the electric motor. In the method, after the transportation device has been vacant for a predetermined time period, said contactor is opened to disable power flow from mains supply to the frequency converter, and a test load is connected to the intermediate circuit, parallel to a capacity of the intermediate circuit. The DC supply voltage U.sub.dc(t) is detected, and the detected DC supply voltage U.sub.dc(t) is utilized for establishing a maintenance information indicating that a maintenance should be done on the frequency converter. Another aspect of the invention is a software program realizing the method when executed on a computer.

The invention relates to a method for maintenance of a frequency converter for driving an electric motor of a transportation device, said frequency converter being supplied with AC mains power via a contactor, and including a rectifier circuit for providing a DC supply voltage, a capacitive intermediate circuit for leveling DC supply voltage, and an inverter circuit for providing power to the electric motor. In the method, after the transportation device has been vacant for a predetermined time period, said contactor is opened to disable power flow from mains supply to the frequency converter, and a test load is connected to the intermediate circuit, parallel to a capacity of the intermediate circuit. The DC supply voltage U.sub.dc(t) is detected, and the detected DC supply voltage U.sub.dc(t) is utilized for establishing a maintenance information indicating that a maintenance should be done on the frequency converter. Another aspect of the invention is a software program realizing the method when executed on a computer.

A matrix converter system having a current control mode operation is provided. The system includes a matrix converter having a switching matrix. The matrix converter is coupled at its low-voltage side to a generator and at its output load side to a load. A controller having a pulse width modulation (PWM) control circuit is configured to control the matrix converter via its switching matrix to increase energy within the internal inductances of the generator when the switching matrix causes a short circuit. A feed forward calculator is configured to calculate a feed forward output phase angle. The feed forward output phase angle is an estimation of an angle between an output current vector and an output voltage vector that represent feedback signals of current and voltage output by the matrix converter. The angular position of the voltage output vector is adjusted as a function of the feed forward output phase angle to align angular position or phase angle of the voltage output vector that represents the voltage output with a selected angular position or phase angle.

A matrix converter system having a current control mode operation is provided. The matrix converter system includes a matrix converter that includes a plurality of switches. A unity current reference vector having an amplitude of one is determined that defines an angle and frequency of an output current vector as a function of a reference phase angle, which is a function of the output current vector and an output voltage vector representing feedback signals of a multiphase signal output to a load. The unity current reference vector is used to control the matrix converter, to cause the output current vector to be aligned with the unity current reference vector. A unity voltage reference vector having an amplitude of one is provided that defines a reference angle and frequency as a function of a zero phase angle. The output voltage vector and the unity voltage reference vector are aligned to determine the reference phase angle as an angle between the aligned output voltage vector and the output current vector.

Unique systems, methods, techniques and apparatuses of motor starters are disclosed. One exemplary embodiment is a synchronous machine including a plurality of stator phase windings, a rotor, a motor starter, and a controller. The motor starter includes a plurality of wye semiconductor switches and a plurality of delta semiconductor switches. The controller is structured to operate the plurality of wye semiconductor switches and the plurality of delta semiconductor switches so as to couple the plurality of stator phase windings in a delta configuration while an angular speed of the rotor is less than a synchronous speed, and structured to operate the plurality of wye semiconductor switches and the plurality of delta semiconductor switches so as to couple the plurality of stator phase windings in a wye configuration in response to the angular speed of the rotor being equal to the synchronous speed.

An energy control circuit is provided. The energy control circuit includes an input circuit; an output circuit; an energy storage circuit coupled between the input circuit and the output circuit; and a controller coupled to the input circuit and output circuit for controlling an amount of energy stored in the energy storage circuit and for controlling a waveform generated by the output circuit using energy stored in the energy storage circuit.

A PCB motor controller comprises relays mounted on a PCB and interconnected to power traces in or on the PCB to receive incoming three-phase power and to output three-phase power to a motor. Control power traces in or on the PCB connect the relays to control circuitry, also mounted on the PCB. A power supply is mounted on the PCB and connected to the control circuitry to provide power for its operation and for switching of the relays. The relays are switched in accordance with a point-on-wave (POW) switching scheme, allowing for the use or relays and the PCB, which may not otherwise be suitable for motor control applications.

A PCB motor controller comprises relays mounted on a PCB and interconnected to power traces in or on the PCB to receive incoming three-phase power and to output three-phase power to a motor. Control power traces in or on the PCB connect the relays to control circuitry, also mounted on the PCB. A power supply is mounted on the PCB and connected to the control circuitry to provide power for its operation and for switching of the relays. The relays are switched in accordance with a point-on-wave (POW) switching scheme, allowing for the use or relays and the PCB, which may not otherwise be suitable for motor control applications.