Abstract: A method and system for sensorless determination of the orientation of the rotor of an ironless PMSM motor from a known rotor angle is described. The method and system include: specifying a rotor system according to the rotor angle; applying voltage pulses to the phases of the motor in the torque-forming direction of the rotor system; measuring the current in the phases of the motor; determining the expected back EMF along the flux-forming axis, based on the measured current; forming an integral of the expected back EMF by time integration of the expected back EMF along the flux-forming axis and/or a filter-based accumulation function; and determining the orientation of the rotor from the algebraic sign of the integral of the expected back EMF and/or the accumulation function.

Abstract: A power transmission unit for controlling a flow of electric energy between two AC power units is provided. The power transmission unit comprises a main transformer having a first winding and a second winding as well as a switchable auxiliary AC unit for applying a tunable auxiliary AC voltage across an auxiliary AC side of the auxiliary AC unit. The auxiliary AC side is connected in series with the first winding of the main transformer to form a series connection. Further, a power conversion unit comprising the power transmission unit and two AC power units as well as a method for controlling a flow of electric energy by using such a power conversion unit are provided.

Abstract: The present disclosure relates to a method for determining the position of a rotor of a polyphase motor, e.g., the rotor angle, particularly at standstill. The method can include: applying voltage to phases of the motor, measuring a current in the phases, and determining the rotor position based on the measured current. According to the present disclosure, determination of the rotor position can be based on current values measured during a period where zero voltage is applied to the respective phases.

Abstract: A power transmission unit for controlling a flow of electric energy between two AC power units is provided. The power transmission unit comprises a main transformer having a first winding and a second winding as well as a switchable auxiliary AC unit for applying a tunable auxiliary AC voltage across an auxiliary AC side of the auxiliary AC unit. The auxiliary AC side is connected in series with the first winding of the main transformer to form a series connection. Further, a power conversion unit comprising the power transmission unit and two AC power units as well as a method for controlling a flow of electric energy by using such a power conversion unit are provided.

Abstract: A method and system for sensorless determination of the orientation of the rotor of an ironless PMSM motor from a known rotor angle is described. The method and system include: specifying a rotor system according to the rotor angle; applying voltage pulses to the phases of the motor in the torque-forming direction of the rotor system; measuring the current in the phases of the motor; determining the expected back EMF along the flux-forming axis, based on the measured current; forming an integral of the expected back EMF by time integration of the expected back EMF along the flux-forming axis and/or a filter-based accumulation function; and determining the orientation of the rotor from the algebraic sign of the integral of the expected back EMF and/or the accumulation function.

Abstract: The present disclosure relates to a method for determining the position of a rotor of a polyphase motor, e.g., the rotor angle, particularly at standstill. The method can include: applying voltage to phases of the motor, measuring a current in the phases, and determining the rotor position based on the measured current. According to the present disclosure, determination of the rotor position can be based on current values measured during a period where zero voltage is applied to the respective phases.