Abstract: The invention relates to a tap changer for voltage regulation, comprising semiconductor switch units (S1.1, . . . , S1.6; S2.1, . . . , S2.6) on a variable transformer having a regulating winding, wherein two parallel load branches (1, 2) are provided, in each of which several series-connected semiconductor switch units are arranged. Parts of the regulating winding (W1, W2, W3) and bridges (B1, B2) are provided alternately and run parallel between the two load branches, alternating such that by corresponding connection of the semiconductor switch units in both load branches, the parts of the regulating wiring can be operated arbitrarily in a subtractive and/or additive manner.

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: There is provided a power plant in which a fossil fuel is used to generate power. An exemplary power plant includes a generator and a turbine that drives the generator, which generates electricity. Also included is a separator with which carbon dioxide is separated out of exhaust gas of the power plant. The power plant further includes a compressor with which the separated carbon dioxide is liquefied, the compressor being coupled to an electric drive.

Abstract: A housing for a semiconductor device is disclosed. In an exemplary embodiment of the present invention, the housing comprises a semiconductor substrate that is arranged between two contact elements, one contact element forming an anode contact element and another contact element forming a cathode contact element, the semiconductor substrate having, on at least one surface, a gate electrode that is contacted by a gate contact element, the first contact element forming a surface arranged across from the gate electrode and at a distance from the gate electrode. Also included is at least one driver unit for generating a gate current, the driver unit comprising a first terminal that is contacted with the gate contact element, and a second terminal that is contacted with a first of the two contact elements.

Abstract: A method and device for determining the charge of a battery, characterized in that a gain crossover frequency (f±) for an impedance of the battery excited by an alternating current signal is established, and the gain crossover frequency (f±) is assigned to the charge of the battery, whereby the gain crossover frequency (f±) is a frequency of the alternating current signal at which an imaginary portion of the impedance of the battery vanishes.

Abstract: A housing for a semiconductor device is disclosed. In an exemplary embodiment of the present invention, the housing comprises a semiconductor substrate that is arranged between two contact elements, one contact element forming an anode contact element and another contact element forming a cathode contact element, the semiconductor substrate having, on at least one surface, a gate electrode that is contacted by a gate contact element, the first contact element forming a surface arranged across from the gate electrode and at a distance from the gate electrode. Also included is at least one driver unit for generating a gate current, the driver unit comprising a first terminal that is contacted with the gate contact element, and a second terminal that is contacted with a first of the two contact elements.

Abstract: A torque shudder protection device for an induction machine includes a flux command generator for supplying a steady state flux command and a torque shudder detector for supplying a status including a negative status to indicate a lack of torque shudder and a positive status to indicate a presence of torque shudder. A flux adapter uses the steady state flux command and the status to supply a present flux command identical to the steady state flux command for a negative status and different from the steady state flux command for a positive status. A limiter can receive the present flux command, prevent the present flux command from exceeding a predetermined maximum flux command magnitude, and supply the present flux command to a field oriented controller.

Abstract: An ac electric drive system includes a bidirectional power semiconductor interface between a battery, or an auxiliary energy storage device, and a power inverter for boosting an input dc voltage and for decoupling the dc link voltage from the input dc voltage such that the dc link voltage is substantially independent of the input dc voltage and the parameters of the battery or energy storage device. The input dc voltage is controlled to maximize efficiency along predetermined torque envelopes.

Abstract: A dual active bridge converter, including high-frequency transformer-coupled input and output bridge converters, receives a rectified ac line voltage via a rectifier acting in a resistive mode and a small, high-frequency filter capacitor. A phase angle controller controls a phase shift between the voltages across the transformer windings such that high-efficiency dc-to-dc conversion is achieved, while maintaining unity power factor at the ac input, using high-density circuitry with small filter components and without adding additional front-end power factor correction circuitry.

Abstract: A current regulator for a four-legged, three-phase inverter determines the next optimal, or near-optimal, inverter state in a relatively short time period based on phase current error signals and back-emf's, resulting in low harmonic distortion, reduced current ripple, minimal current stresses, and increased utilization of the available dc bus voltage over a high bandwidth.

Abstract: A torque feedback system is employed in a universal field-oriented (UFO) controller to tune a torque-producing current command and a slip frequency command in order to achieve robust torque control of an induction machine even in the event of current regulator errors and during transitions between pulse width modulated (PWM) and square wave modes of operation.

Abstract: The direct (d) and quadrature (q) components of flux, as sensed by flux sensors or determined from voltage and current measurements in a direct field orientation scheme, are processed rapidly and accurately to provide flux amplitude and angular position values for use by the vector rotator of a universal field-oriented (UFO) controller. Flux amplitude (linear or squared) is provided as feedback to tune the UFO controller for operation in direct and indirect field orientation modes and enables smooth transitions from one mode to the other.

Abstract: A method for controlling a power converter and an associated auxiliary commutation circuit ensures soft-switching of all switching devices employed therein. Such a power converter includes an inverter with at least two main switching devices per phase. Across each main switching device are connected an antiparallel diode and a relatively large snubber capacitor. The auxiliary resonant commutation circuit comprises two antiparallel-coupled auxiliary switching devices coupled in series with a resonant circuit including an inductor and the snubber capacitors. The gating and conduction times of the main and auxiliary switching devices are controlled so as to add boosting energy to the resonant operation, thus ensuring that the inverter output voltage at least reaches the positive and negative inverter rail voltages during each resonant commutation cycle. As a result, the control achieves commutation of the converter pole with substantially no switching losses.

Abstract: A single-phase, soft-switching, ac-to-dc power converter comprises a rectifier for receiving and rectifying an ac voltage and providing the rectified ac voltage to a boost dc-to-dc converter, which in turn is coupled to an active clamped resonant dc link (ACRDCL). Resonant oscillations of the resonant dc link circuit comprising an inductor and a capacitor are maintained via control of an active clamp switching device. Soft-switching in a discrete pulse modulation scheme is achieved by controlling the switching instants of a boost switching device to occur at zero voltage instants of the resonant dc link. Alternatively, if a pair of snubber capacitors are added to the boost converter, soft-switching may be achieved in a pulse width modulation mode, resulting in reduced subharmonics even at higher frequencies and with smaller filter components.