Abstract: A method for correcting of the flux direction of a modelled flux vector down to zero frequency. The modelled flux vector is formed by a machine model as a function of a stator current vector and a stator voltage vector of a rotating-filed machine that has no sensors. A nominal (command) value for the field-forming (field-producing) and torque-forming current (torque-producing) component of the stator current vector of the rotating-field machine is determined. A current test vector is then added to the nominal (command) value of the field-forming (field-producing) current component. The current test vector has a profile that is non-constant with respect to time. The rotating-filed machine is driven into the saturation region, and the determined voltage vector of the rotating-filed machine is used to recover the response information of the rotor current vector, to which the test movement of the stator current vector is transferred.

Abstract: In the field-oriented control of an asynchronous machine, the flux angle of which is calculated by a flux computer from the current and the voltage as the integral of the EMF, the correct flux vector must be available already at the start-up of the machine. For this purpose, one axis (M.phi.1) of a model coordinate system as well as the components (iO*, iM*=0), referred to the model coordinate system, of a vector parallel to this axis is determined at an input device (E1, E2) by a constant, given starting angle (.phi.MO*). This vector is transformed by means of the field angle (.phi.s) calculated by the flux computer for forming the converter control variables into the stator coordinate system while the machine is excited but standing still. The angle deviation (.phi.MO*-.phi.s) of the calculated field angle from the starting angle is used by a controller (CR) for correcting the calculated field angle.

Abstract: To assure the commutatibility of an intermediate circuit converter with an impressed intermediate circuit d.c. current it is sufficient to limit the rate of rise of the intermediate circuit current under operating conditions to the product f*. i* from the current and frequency of the converter. A rate of rise limited in such a fashion to a maximum value reflecting operating conditions can be preset to a rate of change limiter using a rate of rise limiting controller to which the preset maximum value as well as the rate of rise of the control value for the intermediate circuit current itself has been preset. For that purpose a current controller, whose output signal are connected to suitable control values, assures an immediate control of the intermediate circuit current to the current reference value which has been limited in its rate of rise.

Abstract: An engine or a similar torque generator with internal torque M1 and moment of inertia T1 and an electrical drive with electrical torque M2 and moment of inertia T2 coupled thereto interchange an interchange torque MA over a coupling according to the equation M1=(MA) (1+(5 T)).sup.2 (1.sup.2 +(T1/T2))-M2,(T1/T2). Based on the actual values MA and M2 as well as a parameter (T1/T2)* and a model time constant T*, a model value M* is computed in accordance with this function, which indicates the actual internal torque if said parameters correspond to the actual parameters. Thus, using supplemental set values .DELTA.M2 the preset electrical torque is varied and the parameters calibrated in such a manner that the effect of the M2 variation on the model value virtually disappears.

Abstract: In order to determine from a reference vector (for instance from the EMF vector e.sub.s of a rotating field machine given by the current i.sub.s and the voltage u.sub.s) a model vector by integration (for instance the flux vector) and to thereby suppress defects of technical integrators and instabilities of the circuit used, a correction vector is formed which is rotated relative to the model vector (angle .epsilon..sub..phi.) and of which the magnitude is proportional to the derivative of the vector magnitude, or proportional to another volatile quantity. The model vector itself is obtained by integration of the sum vector formed by the reference vector and correction vector. This "voltage model" can optionally be controlled by a reference vector.

Abstract: For determining the flux vector, an EMF vector (e.sub.s) is formed in an EMF detector (15) from the stator current and the stator voltage, the components of which are determined in a rotating coordinate system rotated by an angle (.beta.) relative to the coordinate system which is fixed with respect to the stator. The flux vector (.psi..sub..beta.) is formed in the rotating coordinate system, taking into consideration the rotary EMF component (e.sub..beta..sup.R) which is generated from the flux vector through rotation by .pi./2 and multiplication by the frequency of rotation (.beta.). The angle of rotation (.beta.) is determined by feeding the direction deviation of the flux vector (.psi..sub..beta.) or a reference vector (.psi.*) for the flux vector by the angle (.beta.) to a servo control (27 or 30, respectively), the output signal of which is fed as the speed of rotation (.beta.) via an integrator (20) for forming the angle of rotation (.beta.).

Abstract: An EMF detector supplies, from the voltage and the current, the EMF vector in a coordinate system fixed in space, the integral of which is the flux vector. The integration is carried out in the field oriented coordinate system, in which the EMF vector is transformed by means of a vector rotator. A rotational component is taken into consideration in the integration by having a first integrator form, from the field parallel EMF component, the magnitude of the flux and having a divider form, from the second EMF component and the magnitude of the flux, the flux frequency, from which frequency an integrator forms simultaneously the flux angle and the angle of rotation for the vector rotator. An angle control input characterizing the steady state and the angle of rotation, through an angle servo control selectably furnishes the field frequency entered into the second integrator to form, from a magnitude servo control, a feedback signal added to the field parallel EMF component.

Abstract: 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.

Abstract: Disclosed is an apparatus for operating a converted-fed asynchronous electric motor which comprises a flux computer for determining the position of the flux vector from the input values for the stator voltage provided by said motor by solving all the electrical quantities of the Park equations describing said motor in a given position of the rotor axis, taking into account the parameter values corresponding to the rotor resistance and the stator resistance of said motor whereby signals corresponding to the position of the flux vector and belonging to a solution, can be tapped from said flux computer; a converter control unit coupled to said flux computer and said convertor rectifier respectively, forming the control quantities for driving the converter rectifier from the determined position of the flux vector and from the nominal input values which fix the components of the stator current vector parallel and perpendicular to the flux vector.

Abstract: Disclosed is a method to detect the rotor resistance of an asynchronous machine, wherein a first vector attached to the emf of the machine is determined by computing the emf-vector or the flux vector from the stator voltages and the stator currents; wherein a flux attached to an arithmetic model circuit is determined, whereas the arithmetic model circuit uses the stator currents and the rotor position of the machine and an adjustable model parameter for the rotor resistance as basic quantities and imitates the dynamic events leading to the magnetic flux of the machine; wherein a difference of two quantities is determined, wherein the first quantity represents a defining quantity of the first vector attached to the machine and the second quantity represents a respective defining quantity of a second vector derivable from the imitated flux and that the setting of a model parameter is varied until the value of the difference is a minimum, whereas the model parameter corresponding to the minimum of the difference

Abstract: Apparatus is disclosed wherein parameter values for the stator resistance, the main inductance and the stray inductance of an asynchronous machine is detected without using information about the rotor position. Thereby the apparatus consists of an EMF-forming circuit, an arithmetic control circuit, an arithmetic model circuit, and a control circuit. All circuits are coupled to form an overall model circuit designed according to a closed loop circuit to simulate the operational conditions of an asynchronous machine. In a balanced position of the control circuit the output signals of the control circuit represent the actual parameter values to be determined.

Abstract: 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.

Abstract: A control unit for regulating an asynchronous motor supplied with power from a three phase network by a line-controlled power converter which is DC coupled to a self-commutated inverter has a function generator and a current regulator which controls the stator current of the motor by the controlling rectifier valves in the inverter. Control of the stator current is a function of a predeterminable value of flux fed into the function generator. In a parallel control system, an actual-value computer and a load state control regulate the stator frequency by generating a signal for controlling the self-commutating converter as a function of the actual values of the stator current, the stator voltage, and a value calculated from the function generator input variable. The computer forms signals corresponding to the amplitude of the flux vector, and to a stator current component perpendicular to the flux vector.

Abstract: For forming ##EQU1## in a pulse width multiplier, two input voltages b.sub.i are summed at the input of an inverter and are added, after each passes through a separate switch and proportional stage, at the input of a smoothing stage, to the inverter output signal. The switches are actuated by switching pulses which are width-modulated in accordance with the factors c.sub.i. The calculated sum is present at the output of the smoothing stage. Great accuracy in field-oriented control of rotating-field machines is possible when vector analyzers and vector rotators designed in this manner are used.

Abstract: A coordinate converter useful for field-oriented control of a rotating-field machine includes a divider, a first adder, a multiplier and a second adder by which the magnitude of the vector and the tangent of the half-angle relative to one axis can be determined. An ancillary unit forms an angle-proportional variable from the half-angle tangent. A rotating vector can also be processed.

Abstract: A coordinate converter distinguished by low cost of hardware and useful for the field-oriented control of a rotating-field machine contains two multipliers, an adder and a subtraction element in a logic circuit. Optionally, two proportional elements can be added thereto. With this coordinate converter, the two Cartesian coordinates can be determined. If the magnitude is constant, the coordinate converter can be used as a sine-cosine generator. In addition, a supplemental circuit for generating a rotating vector is described.

Abstract: A vector analyzer which serves for determining defining quantities of a planar vector in which the output of a digital counter is fed, via sine and cosine function generators, to a vector rotator addressed by the component voltages of an input vector and made to follow the value of the phase angle of the input vector by means of a three point control in order to make the output of the digital overflow counter follow the phase angle of an input vector by means of a control loop; the counter content is reset to zero without problem if the value 360.degree. of the phase angle is exceeded. The invention can be used particularly for field orientation control of rotating field machines.

Abstract: A circuit for forming an electrical quantity which is proportional to a flux component of a rotating field machine permitting an accurate measurement of the flux component during the starting up of the rotating field machine, the machine having for this purpose, two windings of which the first winding is suited for excitation and the second winding for taking off a voltage induced by the excitation, the circuit including an integrator preceded by an adder to which are fed as input variables the phase current, the time derivative of the same, the phase voltage of the rotating field machine, and the induced voltage, with a null regulator which can be switched on via an auxiliary switch after the excitation is switched on connected into the feedback path of the integrator, and a quantity proportional to the flux component taken off at the output of the integrator.

Abstract: A method and apparatus for operating a rotating field machine, which is controlled by an inverter of the type which provides only a predetermined limited number of discrete positions of the stator current vector, in such a manner so that when it is desired to position the machine between two of the discrete vector positions, the discrete positions on each side of the desired vector position are alternatively energized resulting in an average position which is the desired vector position. For operation in a system where the vector can only rotate in one direction apparatus is disclosed which permits the alternate energization to occur by moving the vector at the maximum possible speed over the portion of rotation which is outside an area surrounding the desired position and moving it more slowly while inside this area.