SU512557A1 - Method of controlling a ferromagnetic device - Google Patents

Description

one

The invention relates to electrical engineering, in particular to controlled ferromagnetic devices. There are known methods for controlling ferromagnetic devices that are powered from a three-phase source by transmitting pulses of adjustable width to the control winding. One of the known methods for controlling ferromagnetic magnetically adjustable devices is a method in which positive current feedback of even harmonics is used, and the control signal is supplied in the form of narrow pulses with a double network frequency at the moments of maximum negative half-wave e. d. even harmonics. In devices where even harmonics have a small amplitude (in particular, three-phase switching circuits for single-phase devices with a phase separation of the bias circuit), synchronize the control of their voltage pulses with the maximum moments of the negative half-wave e. d. the harmonics leads to a considerable complication of the control circuit, since the implementation of this method requires a special current transformer, a voltage transformer for matching the output characteristics of the current transformer and the transistor (thyristor) pulse amplifying stage. Another disadvantage of this method is the need to provide

additional cascade synchronization pulses for the minimum current, which reduces stability.

In order to simplify and increase the stability of the regulation according to the proposed method, the pulses of adjustable width, applied to the control winding, are synchronized with one of the instantaneous values of the phase voltages of the three-phase source and are fed from

frequency e. D. s., floppy in the specified control winding.

The method is implemented with the aid of a device whose scheme is shown in the drawing. The device contains nasysh throttles, eni 1-6,

a blocking valve 7, a three-phase transformer 8, a key controlled element 9, a bias source 10 and a load in the form of a three-phase bridge rectifier 11. In the process of operation at saturation throttles

The control circuits are affected by two voltages: a pulse voltage from a bias source and a very small voltage with a frequency of the sixth harmonic e. d. Due to the blocking valve 7, two pulsating control current components flow through the windings of the chokes; the main component is from the source of bias and the small component of the sixth harmonic. In this connection, the stability of the control process and the energy ratios in the bias source and the key element are influenced by the ratio of the frequencies of the key element and the primary source of electricity and the phase constant of the control unit pulses relative to any of the instantaneous values of operating currents of chokes voltage or phase (linear) voltage of a power transformer. Therefore, to increase the stability of the regulator, the pulse frequency of the key controlled element 9 is synchronized with one of the instantaneous values of the phase (linear) source voltage. The synchronization of the control, their pulses, is carried out from the additional low-power phase windings of the power transformer or a three-phase transformer that supplies the control circuit. The application of the proposed method allows to reduce the number of bias sources, power sources of key elements, as well as to exclude current transformers, separation pulse transformers and an additional cascade synchronizing, which increases the reliability of the device.

Claims (1)

Invention Formula The control method of the ferromagnetic device, which is powered from a three-phase source, by applying control pulses of adjustable width to the winding, characterized in that, in order to simplify and increase the control stability, these pulses are synchronized with one of the instantaneous values of the phase voltages of said source and served with frequency e. D. s., induced in the specified control winding.