Siemens Aktiengesellschaft

Primetals Technologies Germany Gmbh

Siemens Healthineers Ag

Martin Hergt

Markus Vester

Werner Hartmann

Hubertus Fischer

Thomas Kundner

Oliver Heid

Arne Reykowski

Jan Bollenbeck

Manfred Baldauf

Thomas Matschullat

Mario Festag

Jürgen Rupp

Arno Döbbeler

Markus Zocher

Detlef Rieger

Christian Schacherer

Markus Pfeifer

Marcel Lutze

Sebastian Nielebock

Klaus Krüger

Arno Doebbeler

Juergen Rupp

Björn Dittmer

Divya Kurthakoti Chandrashekhara

Martin Helsper

Marc Hiller

Vico Haverkamp

Rainer Graba

A DC-to-DC converter converts a DC input voltage to a DC output voltage by generating a primary AC voltage and transforming the primary AC voltage into a secondary AC voltage with a transformation ratio. The DC-to-DC converter has series resonance circuit for each AC voltage phase. When the ratio of the DC output voltage to the DC input direct voltage is greater than the transformation ratio, a phase shift between the primary alternating voltage and a series resonance circuit current corresponding to the primary alternating voltage is controlled to zero by changing a clocking frequency clocking the AC voltages. Conversely, when the ratio of the DC output voltage to the DC input voltage is less than the transformation ratio, the phase shift between the secondary AC voltage and a series resonance circuit current corresponding to the secondary AC voltage is controlled to zero by changing a clocking frequency.

DC-to-dC converter and operation thereof

A resonant DC-DC converter includes an inverter circuit, a rectifier circuit and a transformer unit. The inverter circuit is connected to a first terminal of the transformer unit, and the rectifier circuit is connected to a second terminal of the transformer unit. The first and second terminals are galvanically isolated from one another by a first transformer. The transformer unit is configured to adapt a transformation ratio of the transformer unit. The transformer unit has an energy transmission path which includes an inverter and a second transformer, with an input of the energy transmission path being arranged parallel to a primary side of the first transformer and an output of the energy transmission path being arranged in series with the secondary side of the first transformer.

Resonant DC-DC converter

An electric arc furnace () operated with alternating current has a converter () which converts mains voltage (U), into primary voltage (U') having a furnace frequency (f&#x2032;). A furnace transformer () transforms the primary voltage (U&#x2032;) into a secondary voltage (U&#x2033;), supplied to electrodes () in a furnace vessel () (). They apply electric arcs () to a melt material () in the vessel (). The secondary voltage (U&#x2033;) is also supplied to a capacitor assembly () on the output side of the furnace transformer () and the furnace transformer () is connected on the output side. A control device () controls the converter () such that a primary voltage (U&#x2032;) output from the converter () to the furnace transformer () has a furnace frequency (f) of least ten times the mains frequency (f) and/or greater than 1 kHz.

Converter-fed electric arc furnace with capacitor assembly in the secondary circuit

An apparatus for regulating an electric arc furnace connected to a power supply system with at least one system phase that applies an AC voltage to a furnace electrode and an arc current for melting. A control loop device includes an electrical converter designed for negative feedback of an amplitude and/or frequency of the AC voltage to produce an amplitude and/or frequency of the arc current. The converter includes an input port having a system power supply connected thereto, and an output port having a melting furnace power supply and a primary circuit of a first transformer connected thereto, wherein a secondary circuit of the first transformer is connected to the arc furnace electrode. A primary coil of a second transformer is connected in parallel with the converter input port, and a secondary coil of the first transformer is connected in series with a secondary coil of the second transformer.

Apparatus and method for dynamically adjusting an electric arc furnace

A transformer including a coaxial transmission line and a series circuit of discrete stages of voltage sources arranged along a main axis of wave propagation. Electromagnetic waves are propagated along the coaxial transmission line in each stage and are coupled in the coaxial transmission line by pulse currents. Each stage has a coupling-in inductance formed by discrete inductances that generate the pulse currents. The discrete inductances are magnetically coupled to each other such that magnetic fluxes of the discrete inductances are superimposed on one another and added to one another along a circular line that is rotationally symmetrical to the main axis of wave propagation.

Inductive isolation of voltage sources of an inductive voltage adder by individual coupled coils

The invention refers to a multilevel topology power converter (I) for electrical adaption of a low voltage alternating current (LVAC) of an electrical wind power generator () and a medium voltage (MV) transmission level for a transmission link to each other, the power converter (I) comprising for each phase:

Wind turbine power conversion system

In a mixer circuit with a balanced frequency mixer with varactor diodes, a first input signal that exhibits a first input frequency can be fed to the frequency mixer via a first input. Furthermore, a second input signal that exhibits a second input frequency can be fed to the frequency mixer via a second input. The frequency mixer has at least two amplifier elements fashioned as varactor diodes. These amplifier elements mix the input signals with one another into a mix signal with a first signal component and a second signal component. The first signal component exhibits a first component frequency, the second signal component a second component frequency. The first component frequency is equal to the sum of the first and second input frequencies, the second component frequency is equal to the difference of the first and second input frequencies. An output signal that contains at least one of the signal components can be tapped via the output. The frequency mixer is fashioned as a balanced frequency mixer in which at least the second input and the output are decoupled from one another. The second input frequency is a multiple of the first input frequency. An adjustment circuit for adjustment of an operating point of the varactor diodes is connected in parallel with each varactor diode.

Mixer circuit with balanced frequency mixer with varactor diodes

A radio-frequency coil arrangement has a number of conductor traces forming basic coils and with capacitors interconnected in the conductor traces. Conductor traces of various basic coils intersect at node points. At least one switching arrangement for selective, reversible connection of the conductor traces to form different coil geometries is provided at least some of the node points.

Radio-frequency coil arrangement

In a transmission device for use in magnetic resonance systems for transmitting magnetic resonance signals from a number of local coils to an evaluation device, the signals are transmitted as optical signals in an optical conductor between a first transmitter-side transducer that transduces electrical signals into optical signals and a second receiver-side transducer that transduces optical signals into electrical signals, and an analog/digital converter is respectively provided between the local coils and the first, transmitter-side transducer. The local coils are connected by electronic elements to a single circuit board, and a number of preamplifiers, the analog/digital converters and a multiplexer are integrated onto the circuit board such that the multiplexer merges the outputs of the multiple analog/digital converters.

Device and method for optical transmission of magnetic resonance signals in magnetic resonance systems

A magnetic resonance system that has a magnet system that generates magnetic fields in an excitation region, allowing nuclei in an examination subject in the excitation region to be excited to emit a magnetic resonance signal. A reception antenna device with multiple local coils for reception of the magnetic resonance signals is arranged in proximity to the examination subject, and has a base part and an attachment part. The attachment part can be placed on the base part such that the examination subject is located between the base part and the attachment part (). The multiple local coils are respectively connected with an evaluation device for evaluation of magnetic resonance signals. To simply and reliably couple the antenna devices to an evaluation device with optimally few electrical conductors being located in the excitation region, the multiple local coils in the attachment part are respectively connected with the evaluation device via a base coupling element that is arranged at a predetermined base part location on the base part and an attachment coupling element is arranged at a predetermined attachment part location on the attachment part. The magnetic resonance signal received by the local coil can be fed to the evaluation device via the attachment coupling element and the base coupling element and as long as the attachment part is placed on the base part.

Magnetic resonance system with reception antenna device

A magnetic resonance system has a base unit and a patient bed. The base unit embodies a magnet system by which magnetic fields can be generated in an excitation region, these magnetic fields causing nuclear spins in an examination subject in the excitation region to be excited to emit a magnetic resonance signal. The patient bed can be moved in a travel direction relative to the base body over a travel range. By movement of the patient bed the examination subject can be brought into the excitation region. A number of base unit coupling elements that are connected with an evaluation device for evaluation of magnetic resonance signals are arranged to be stationary at the base unit relative to the base unit. A number of patient bed coupling elements that are connected with a local coil for acquisition of the magnetic resonance signal are arranged on the patient bed so as to be stationary relative to the patient bed. The base unit coupling elements and the patient bed coupling elements are arranged and fashioned such that the magnetic resonance signal acquired by the local coil can be fed via the patient bed coupling elements and the base unit coupling elements to the evaluation device when and as long as the patient bed has moved by a predetermined segment of the travel range. A degree of coupling with which the patient bed coupling elements and the base unit coupling elements and coupled with one another in total is constant within the segment of the travel range.

Magnetic resonance system with coupling between a base unit and a local coil at the patient bed

A sheath wave barrier unit for an outer shielding of a coaxial cable that also has an inner conductor, has two sheath wave barriers that damp or suppress sheath waves that are induced in two series conductor segments of the outer shielding. Each sheath wave barrier forms a resonant oscillating circuit at a predetermined high frequency, with the high frequency being the same for both sheath wave barriers. The sheath wave barrier unit has a shielding device with at least one radial shield by means of which the sheath wave barriers are decoupled from one another. The sheath wave barriers and the shielding device are arranged on a common carrier.

Growing community of inventors

Nuremberg, Germany

Martin Hergt