Abstract: A transformer includes a first core, a first primary coil, a first secondary coil, and a first insulating member. The first secondary coil includes a second conductor wound around the first core. The first insulating member covers the first secondary coil. The second conductor has a shape of a first polygon in a cross-section of the second conductor. A first corner of the first polygon has a first radius of curvature of 0.1 mm or more. The transformer thus has improved dielectric breakdown voltage and improved power efficiency.

Abstract: The invention relates to a method of manufacturing a rotor for an electric machine, wherein the rotor is composed of at least one electric sheet wherein at least one electric sheet is thermally treated regionally to directly modify its magnetic permeability in the treated region.

Abstract: An electrical circuit comprising an n-port m-phase active bridge converter with n?2 and m?3, where each port can be operated as an input or an output port, wherein each of the n ports has m phase legs with multiple active switches with parallel connected snubber or resonant capacitors, whereby the ports can convert a DC-voltage into an AC voltage and vice versa, whereby the ports are connected via a m-phase transformer or over m separate transformers each connected to each of the m phase legs of each of the m ports to transfer power between the ports, wherein an auxiliary circuit is connected to a star point of the transformers to feedback a fraction of a transformer input voltage and energy into a DC mid-point capacitor of a DC-link of at least one of the n-port m-phase active bridge converters to charge the DC mid-point capacitor.

Abstract: A transformer includes a first core, a first primary coil, a first secondary coil, and a first insulating member. The first secondary coil includes a second conductor wound around the first core. The first insulating member covers the first secondary coil. The second conductor has a shape of a first polygon in a cross-section of the second conductor. A first corner of the first polygon has a first radius of curvature of 0.1 mm or more. The transformer thus has improved dielectric breakdown voltage and improved power efficiency.

Abstract: A method of controlling at least one switching module having commutation cells which are associated with a regulating winding of a regulating transformer, the commutation cells including: a first and second switching element each having two thyristors in antiparallel connection.

Abstract: An electrical circuit comprising an n-port m-phase active bridge converter with n?2 and m?1, where each port can be operated as an input or an output port, wherein each of the n ports has m phase legs with multiple active switches with parallel connected snubber or resonant capacitors, whereby the n ports can convert a DC-voltage into an AC voltage, the n ports connected via an m-phase transformer or over m separate transformers each connected to each of the m phase legs of each of the n ports to transfer power between the ports, wherein an auxiliary circuit is connected to the transformers to convert a part of a transformer input voltage and energy via an auxiliary voltage source into a DC mid-point capacitor of a DC-link of at least one of the n-port m-phase active bridge converters to recharge the DC mid-point capacitor.

Abstract: Each DC/DC converter includes a transformer, first and second switching circuits each formed of a plurality of legs having a plurality of semiconductor switching elements, and capacitors. When detecting a malfunction in semiconductor switching elements, a control circuit halts a normal operation mode and controls the first switching circuit by a protection mode for turning OFF all the semiconductor switching elements, and controls the second switching circuit by a bypass mode for bypassing the capacitor by turning ON the semiconductor switching elements in a discharge leg and causing a short circuit between the secondary side terminals, after controlling the second switching circuit by a discharge mode for discharging the capacitor by turning ON the semiconductor switching element in a discharge leg.

Abstract: An electrical circuit comprising an n-port m-phase active bridge converter with n?2 and m?3, where each port can be operated as an input or an output port, wherein each of the n ports has m phase legs with multiple active switches with parallel connected snubber or resonant capacitors, whereby the ports can convert a DC-voltage into an AC voltage and vice versa, whereby the ports are connected via a m-phase transformer or over m separate transformers each connected to each of the m phase legs of each of the m ports to transfer power between the ports, wherein an auxiliary circuit is connected to a star point of the transformers to feedback a fraction of a transformer input voltage and energy into a DC mid-point capacitor of a DC-link of at least one of the n-port m-phase active bridge converters to charge the DC mid-point capacitor.

Abstract: An electrical circuit comprising an n-port m-phase active bridge converter with n?2 and m?1, where each port can be operated as an input or an output port, wherein each of the n ports has m phase legs with multiple active switches with parallel connected snubber or resonant capacitors, whereby the n ports can convert a DC-voltage into an AC voltage, the n ports connected via an m-phase transformer or over m separate transformers each connected to each of the m phase legs of each of the n ports to transfer power between the ports, wherein an auxiliary circuit is connected to the transformers to convert a part of a transformer input voltage and energy via an auxiliary voltage source into a DC mid-point capacitor of a DC-link of at least one of the n-port m-phase active bridge converters to recharge the DC mid-point capacitor.

Abstract: A circuit assembly for linking different electrical voltage levels in a motor vehicle, comprising: an electric machine containing induction coils in a star circuit connection with a star point; a first switch unit containing switch elements for generating an AC voltage for the electric machine from a DC voltage of a first voltage level; a DC voltage of a second voltage level; and a second switch unit for a bidirectional electrical energy flow between the DC voltage of the first voltage level and the DC voltage of the second voltage level, wherein the second switch unit has two switch elements arranged in series in an auxiliary switch branch, wherein the auxiliary switch branch is connected in parallel to the DC voltage of the first voltage level, and each connection of the switch elements is connected to the star point.

Abstract: Each DC/DC converter includes a transformer, first and second switching circuits each formed of a plurality of legs having a plurality of semiconductor switching elements, and capacitors. When detecting a malfunction in semiconductor switching elements, a control circuit halts a normal operation mode and controls the first switching circuit by a protection mode for turning OFF all the semiconductor switching elements, and controls the second switching circuit by a bypass mode for bypassing the capacitor by turning ON the semiconductor switching elements in a discharge leg and causing a short circuit between the secondary side terminals, after controlling the second switching circuit by a discharge mode for discharging the capacitor by turning ON the semiconductor switching element in a discharge leg.

Abstract: Each DC/DC converter includes a transformer, first and second switching circuits each formed of a plurality of legs having a plurality of semiconductor switching elements, capacitors, a discharge circuit connected in parallel to the secondary side capacitor, and a bypass switch for bypassing the capacitor. When detecting a malfunction in semiconductor switching elements, a control circuit turns OFF all of the semiconductor switching elements, and controls the bypass switch after discharge of the capacitor through the discharge circuit, so that the capacitor is bypassed.

Abstract: Each DC/DC converter includes a transformer, first and second switching circuits each formed of a plurality of legs having a plurality of semiconductor switching elements, capacitors, a discharge circuit connected in parallel to the secondary side capacitor, and a bypass switch for bypassing the capacitor. When detecting a malfunction in semiconductor switching elements, a control circuit turns OFF all of the semiconductor switching elements, and controls the bypass switch after discharge of the capacitor through the discharge circuit, so that the capacitor is bypassed.

Abstract: The present invention relates to an aircraft with at least one synchronous reluctance machine which comprises a stator with a plurality of grooves and teeth and a rotor with a plurality of magnetic flux barriers, wherein at least one magnetic flux barrier is designed asymmetrical to the q-axis.

Abstract: A circuit assembly for linking different electrical voltage levels in a motor vehicle, comprising: an electric machine containing induction coils in a star circuit connection with a star point; a first switch unit containing switch elements for generating an AC voltage for the electric machine from a DC voltage of a first voltage level; a DC voltage of a second voltage level; and a second switch unit for a bidirectional electrical energy flow between the DC voltage of the first voltage level and the DC voltage of the second voltage level, wherein the second switch unit has two switch elements arranged in series in an auxiliary switch branch, wherein the auxiliary switch branch is connected in parallel to the DC voltage of the first voltage level, and each connection of the switch elements is connected to the star point.

Abstract: The invention relates to a method of manufacturing a rotor for an electric machine, wherein the rotor is composed of at least one electric sheet wherein at least one electric sheet is thermally treated regionally to directly modify its magnetic permeability in the treated region.

Abstract: A DC-DC converter having a primary side comprising at least three actively switched primary voltage bridges with several active switches for converting a DC input voltage into primary alternating voltages for each of the primary voltage bridges, and having a secondary side comprising at least three actively switched secondary voltage bridges with several active switches for converting the secondary alternating voltages into a shared DC output voltage for each of the secondary voltage bridges. The primary and secondary alternating voltages are each shifted by a phase angle ? with the periods T, and each of the primary and secondary voltage bridges is coupled to an appertaining phase via one or more transformers.

Abstract: The present invention relates to an aircraft with at least one synchronous reluctance machine which comprises a stator with a plurality of grooves and teeth and a rotor with a plurality of magnetic flux barriers, wherein at least one magnetic flux barrier is designed asymmetrical to the q-axis.

Abstract: The invention puts forward a bidirectional DC-DC converter for high voltages that is as simple as possible and that entails as few losses as possible. The bidirectional DC-DC converter (1) converter comprises an input stage (2) to convert a DC input voltage into first AC voltage, a transformer (3) to transform the first AC voltage into a second AC voltage, and an output stage (4) to convert the second AC voltage into a DC output voltage, whereby, in order to provide the first and/or second AC voltage, at least one of the input stages (2) and/or output stages (4) comprises a branch of a multi-level converter (5) with a first number of active first semiconductor switches (61).

Abstract: A DC-DC converter having a primary side comprising at least three actively switched primary voltage bridges with several active switches for converting a DC input voltage into primary alternating voltages for each of the primary voltage bridges, and having a secondary side comprising at least three actively switched secondary voltage bridges with several active switches for converting the secondary alternating voltages into a shared DC output voltage for each of the secondary voltage bridges. The primary and secondary alternating voltages are each shifted by a phase angle ? with the periods T, and each of the primary and secondary voltage bridges is coupled to an appertaining phase via one or more transformers.