Siemens Aktiengesellschaft

Hartmut Vogt

Jens Hamann

Hans-Hermann Zander

Albrecht Storath

Erich Voss

Ekkehard Reuss

A method and apparatus for preventing a current collapse in a phase not participating in the commutation, of a three-phase block current supplied synchronous machine, while the phase currents of the other two phases are being commutated. A control voltage controlling the synchronous machine is acted upon during the commutation of two phase currents by an additional control voltage such that the average of current drop in the down-commutating phase is equal to the average of the negative current rise in the up-commutating phase. Thus, a method and a circuit arrangement for carrying out this method are obtained with which the torque oscillations of a three-phase-feed drive can be reduced substantially.

Method and apparatus for preventing a current collapse in a phase not

A method for reducing a current break in a leg of a three-phase block current-fed synchronous machine that is not participating in a commutation while the currents in the other two legs are commutating. A triangular high frequency sampling voltage from a pulse frequency generator of a control unit for the converter that feeds the synchronous machine is always shorted at the beginning of the commutation for a predetermined synchronization time. The torque ripple of a three-phase feed drive is reduced using this method and the circuit arrangement for carrying out the method.

Method and apparatus for reducing a current break in a leg that is not

A method and circuit for monitoring phase voltages of a polyphase tachometer generator to detect a phase failure, where the tachometer generator is associated with a rotor position transmitter. The phase voltages are added up by a summing stage to form an auxiliary voltage. The auxiliary voltage is sampled at every commutation instant determined by a rotor position signal generated by the rotor position transmitter during a predetermined measuring time. This sampled voltage value is compared with a predetermined voltage value range. An indication of a tachometer fault is displayed as soon as a sampled voltage value is outside the predetermined voltage value range. By this method and circuit, a fault which occurs between two commutation instants can be detected at the next commutation instant.

Apparatus for monitoring phase voltages of a polyphase tachometer

The disclosure is related to a driving arrangement for a drive motor which is provided with an electronic power stage (9) which is controlled by a current controller (13). During the commutation phase, a breakdown of the torque occurs in such drive motors due to the shape of the B-field current, so that the torque has a wavy shape. The torque breakdown can be counteracted by raising the load current in the commutation region. This raising of the load current during the commutation phase is achieved by the provision that the current reference value of the current controller (13) is increased correspondingly by means of an auxiliary voltage at the respective commutation instant.

Driving arrangement for a drive motor

An apparatus and method for increasing the maximum speed of rotation of a synchronous machine having constant excitation field strength is disclosed. The synchronous machine is preceded by a converter, which has an adjusted current reference value as an input. The adjusted current reference value comprises an active-current reference value and a reactive-current reference value. For actual speeds n.sub.ist, the absolute value .vertline.n.sub.ist .vertline. of which is above a predetermined value n.sub.o, the amplitude of the active-current reference value is limited to a value which is inversely proportional to the factor .vertline.n.sub.ist .vertline./n.sub.o. The value n.sub.o is a predetermined speed at which the sum of the magnet wheel voltage of the synchronous machine and the voltage drop in the stator winding is maximally equal to the largest possible output voltage of the converter. To obtain the adjusted current reference value, a reactive-current reference value shifted 90.degree. relative to the active-current reference value is vectorially added to the active-current reference value, the amplitude of the reactive-current reference value being proportional to the factor (1-n.sub.o /.vertline.n.sub.ist .vertline.). A reactive current is thus generated in the machine. The voltage drop across the reactance of the synchronous machine caused by this reactive current is 180.degree. out of phase with the speedproportional magnet-wheel voltage. The magnet wheel voltage can therefore be increased beyond the terminal voltage, so that the speed of rotation of the machine can be increased.

Growing community of inventors

Herzogenaurach, Germany

Hartmut Vogt