SU143108A1 - Device for driving a synchronous machine - Google Patents

Description

The use of a double-frequency rectified current in a rotor winding with stator voltage unbalance is used to excite synchronous machines.

Existing compounding devices without voltage correction do not provide proper control. Applying the same correction to voltage increases the cost of small power plants, since the cost of the corrector greatly exceeds the cost of the caMoii machine.

The proposed device regulates the excitation of synchronous maschiny under asymmetric load. The device differs from those known in that, in order to correct the voltage, an unbalanced load (especially low-power synchronous generators) a choke is connected to the field circuit, in parallel to which a rectifier bridge is connected through capacitors, the output of which is connected to a parallel exciter . Such a device provides high-quality control of excitation under asymmetrical loads and is of low cost.

FIG. 1 is a schematic diagram of the device; in fig. shows the curves of the dependence of the voltage on the strength of the current, obtained by experimental means. The device consists of two electrolytic capacitors С If ,,,, rectifier B and locking throttle DR- The control resistor of the switchgear is connected to the control circuit of rectifier B. The rectified voltage is applied to the RS shunt resistor.

The device works as follows. With an unbalanced load of a synchronous three-phase generator, a reverse-synchronic field appears, which induces a double-frequency current in relation to the stator current frequency in the generator's rotor winding.

For a double frequency current, a circuit consisting of two capacitors (capacitors) and a choke (inductor) is a filter that sucks the alternating current of the rotor (through the capacitors and the rectifier).

The rectified current, the passage through the shunt rheostat, is added (with an agreement to the switch) with the excitation current, and this is a regulating effect.

Curve / (Fig. 2) shows the dependence of the average generator voltage on the current-single-phase load at a sozf 0.5 without a corrector;

curve 2 — with sozf 0.8 and a three-phase symmetric load, when the compounding device acts without a corrector, and

curve - shows the effect of the compounding device with a corrector with a single-phase load (asymmetrical) and a power factor of 0.8.

With a symmetrical generator load, the effect of the device is not effective.

The device is inexpensive to manufacture, and can be widely used to qualitatively control the excitation of synchronous machines in mobile automated power stations of low power.

The device is new and useful and is of practical interest especially for low-power generators. At present, it is successfully used on one of the Volgograd Region's RS.

Subject matter

A device for driving a synchronous machine using double-frequency currents arising in the rotor winding with stator voltage imbalance, characterized in that, in order to correct the voltage of the synchronous generator (especially low-power) with an unbalanced load, the choke is connected A rectifying bridge is connected through the capacitors, and the output of the rectifying bridge is connected in parallel to the adjusting rheostat in the exciter circuit.