Siemens Aktiengesellschaft

Theodor Salzmann

Felix Blaschke

Michael Peppel

Walter Dreiseitl

Johann Thomas Wokusch

Wolfgang Timpe

Rolf-Dieter Klug

Wolf-Dieter Weigel

Thomas Schlegel

Dieter Kollensperger

Marc Hiller

Rainer Sommer

Manfred Weibelzahl

Rainer Marquardt

Tomas Greif

Joachim Holtz

Norbert Klaassen

Samir Salama

Franz Wesselak

Hans-J&uuml;rgen M&uuml;ller

The invention relates to a wind power plant () which consists of a nacelle () arranged on a tower (), a rotor (), a generator (), a power converter () on the generator side, a power converter () on the network side and a transformer (), the two power converters () being electrically connected to each other on the DC voltage side, and the power converter () on the network side being connected on the AC voltage side to a feeding point () of a destination network () by means of the transformer (). Every phase module () of the power converter () on the network side has an upper and lower valve branch (T, T, T; T, T, T) having at least two bipolar subsystems () that are connected in series and the power converter () on the generator side and the power converter () on the network side are interconnected on the DC side by means of a DC cable (). A corresponding wind farm () consists of a plurality of wind power stations () and has a flexible design as compared to known DC concepts, the nacelles () of every wind power station () having a low dead weight.

Wind farm having a plurality of wind energy installations

An air-cooled power converter with gate turn-off power semiconductors, is described in which the cooling capacity is such that the temperature of the gate turn-off power semiconductor does not exceed a critical temperature limit, the power converter having optimized heat sinks, at least some of which are thermally connected in parallel, and the power converter is designed to operate at a continuous load of 1 to 20 megawatts, preferably of 2 to 10 megawatts.

Air-cooled power converter, drive device for rolling stands, and power converter system

A drive system for industrial plant sections, in particular for system sections in the basic industries, having at least one electric motor and at least one converter with a voltage link, through which the electric motor is connected to an AC-voltage power supply network, the converter regulating the power consumption or torque and rotation speed of the electric motor from the AC-voltage power supply network.

Driving mechanism for industrial installations, in particular for primary industry installations

A driving arrangement for rolling stands of a rolling mill, is described. The driving arrangement includes a control system which prescribes desired values for the rolling stands via control units, the rolling stands having at least one electric motor which is supplied with electric energy by a power supply system via at least one converter having turn-off power semiconductors. The converter has an air-cooled design. The cooling power is dimensioned such that the temperature of the turn-off power semiconductors does not exceed a critical temperature limit for continuous operation. The converter includes heat sinks which have an optimum design. At least some of the heat sinks are connected thermally in parallel.

Drive device for roll stands

A three-level inverter, in which the upper and lower half of each phase relieves the semiconductor switching elements from excessive values of the rate of rise of the recurring positive forward blocking voltage. This is done with a circuit arrangement in each half has a wiring diode, a switching off relief capacitor, a further wiring diode, a storage capacitor and a discharging resistor serving as the d-c load. Additional energy feedback devices feed back, into the supplying d-c voltage source, energy which is produced in the switching-off process and is temporarily stored in the circuitry.

Switching-relieved low-loss three-level inverter

This invention concerns a procedure to operate a turn-off thyristor which can be set to a current-conducting state or a current-blocking state as a function of a switch-on command or a switch-off command. To permit particularly reliable and optimal operation of the turn-off thyristor, the voltage between its gate terminal, G, and its cathode terminal, K, is detected and when it drops below a negative threshold current value U.sub.GKS, a status signal, Z, is generated which indicates the current-blocking state of the turn-off thyristor. A further embodiment detects the gate current of the turn-off thyristor and after the appearance of the switch-off command, the status signal is generated as the polarity changes in accordance with the time derivative of the gate current. An overload of the turn-off thyristor is best recognized by having simultaneous to the appearance of the switch-off command, a time function with a preset expiration time initiated, and having a malfunction notification signal, F, generated for protective ignition of the turn-off thyristor if the time function expires prior to the appearance of the status signal.

Procedure and device for detecting the non-conducting state of turn-off

For recognizing the blocked state of a thyristor which can be switched off (GTO thyristor), especially also if it is alloyed through or the driver addressing the thyristor is defective, a state signal indicating the actual advent of the blocked state is generated after the occurrence of a turn-off signal, if the derivative in time of the gate current has exceeded a positive upper limit, which indicates that the thyristor has been turned off successfully. The maxima of the derivative in time of the gate current are almost independent of the actual anode-cathode current to be extinguished. The derivitive in time of the gate current is advantageously determined via a coupling inductance. Preferably, the method and apparatus are used with a mutual adaptive turn-on interlock of GTO thyristors in converter equipment and can be urged to release protective measures in time if permanent conduction (short circuiting) of a thyristor occurs.

Method and apparatus for recognizing the cutoff state of a thyristor

Apparatus for controlling a salient-pole machine includes a stator current control element to make the stator current i.sup.S follow preset desired values i.sub..phi..sup.S*. A field current control element develops from preset desired flux values .psi.*, from the flux signal output of a flux computer (direction .phi..sub.L) and from an inductance parameter (the shunt inductance X.sub.q of the machine) a fictitious field current value signal i.sub.O.sup.E*, which represents the field current value which would be used to control a hypothetical nonsalient-pole machine. This signal i.sub.O.sup.E* is modified by a correction factor derived from the product of the longitudinal component of the flux .psi..sub.d (from the flux computer) and the different between the reciprocals ((1/X.sub.q)-(1/X.sub.d)) of the shunt and series inductances of the machine, to give a field current control signal that accounts for the asymmetry of the salient-pole machine.

Apparatus for the control of a salient-pole machine

In a rotating machine converter controlled drive, the EMF vector components formed from the stator current and stator voltage are integrated by means of a-c voltage integrators, the output quantities of which establish the components of the machine flux vector. In the converter control the parallel and normal components of the stator current relative to this flux vector are introduced. The a-c voltage integrators include zero controllers in a feedback circuit, into which the difference between the machine flux components and corresponding model flux components are introduced. The model flux components are calculated in a computing model circuit from the stator current, magnetization current and rotor position.

Rotating field machine drive

A system for controlling the current of a direct converter or a pulse inverter having m subconverters, each such subconverter having two outputs. One of the outputs is connected to a neutral point of the converter, and not to a load. The other output of each subconverter is provided with a separate current regulator, and connected to the load. Divergence between the voltage of the neutral point of the converter and the neutral point of the load is prevented by providing a controller with a resistive feedback line.

Polyphase frequency converter with individually current-regulated outputs

For forming an electric voltage signal which is proportional to a flux component of a rotating-field machine, a voltage associated with the flux component is fed to the input of an integrator, and a voltage signal proportional to the flux component is taken off of the integrator. The input of a zero-controller for suppressing the DC component of this voltage signal is connected to the output of the integrator and the output of the zero-controller is connected to a summing point at the input of the integrator. This integrator circuit can be used to determine the position of the flux of a rotating field machine, with the correct phase and amplitude, and independently of frequency, while the zero-controller remains engaged at speeds from the beginning of localization of standing rotor position up to the nominal frequency of the machine. The zero-controller has a P-controller and an I-controller whose output signals are fed to the summing point. The output signal of the integrator, weighted in proportion to the frequency of the machine, is fed to the input of the P-controller and, weighted in proportion to the square of the frequency, is fed to the input of the I-controller, the weighting factor having a maximum value of one. The circuit constitutes an AC voltage integrator having a characteristic frequency which depends on the frequency of the rotating field machine, the intercept frequency and the attenuation remaining constant. The phase error remains constant over the entire speed range of the rotating field machine.

Circuit for generating an electric signal proportional to a flux

A drive for a rotating field machine which has two AC voltage integrators of identical design for forming two electric voltage signals each of which is proportional to a flux component in the machine. Each voltage integrator includes an integrator and a zero-controller having negative feedback for suppressing the DC component of input voltages fed to a summing point of the integrator. Each integrator, is fed, as one input voltage, a voltage proportional to the phase-voltage belonging to the flux component and a voltage proportional to the corresponding stator current in a machine supply lead, for compensating the ohmic stator voltage drop. A second voltage, also depending on the phase current, is processed to compensate for the inductive stator voltage drop. To ensure optimum converter and machine utilization over an increased speed control range by reducing the phase errors of the determined flux components, each zero-controller includes a proportional controller and an integrated controller having output signals fed to the summing point. The output signal of the integrator, corrected for the ohmic stator voltage drop and the inductive stray voltage, is fed, weighted proportionally to the frequency of the machine, to the input of the proportional controller, and weighted proportionally to the square of the frequency, to the input of the integrated controller, the weighting factor having a maximum value of 1.

Rotating field machine drive and method

A circuit arrangement is disclosed comprising a converter for converting a three-phase system of sinusoidal voltages into three trapezoidal control voltages for controlling control units serving three direct cycloconverters. More particularly, in accord with the invention, the converter acts on the sinusoidal control voltages such that during each region from .pi./3 to 2.pi./3 of a half-wave of each particular voltage that voltage is reduced to .sqroot.3/2 times its peak value, while the other two voltages are amplified or increased by an amount equal to the difference between the aforesaid peak value and .sqroot.3/2 times such peak value.

Circuit arrangement with a number of cycloconverters, particularly

A circuit arrangement is disclosed comprising three direct converters which are fed from an a.c. voltage network. The converters are arranged in a Y configuration and are connected to a three-phase load. To increase the transmitted power and to vary the reactive power requirement, the circuit arrangement is provided with means for generating a control voltage for the control unit of at least one of the three converters such that the output voltage of this converter has a periodic waveform which includes essentially no fifth and seventh order harmonics. Additionally, the load-side conductor currents of the three converters are controlled with control signals having sinusoidal waveforms. A particular form used for the control voltage is a trapezoidal waveform.

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Erlangen, Germany

Theodor Salzmann