SU450294A1 - Three phase static frequency doubler - Google Patents

Description

one

This invention relates to static frequency converters.

Three-phase static frequency doublers are known, with a circular magnetic circuit with grooves evenly distributed around the circles in which the primary and secondary three-phase windings are laid.

The proposed frequency doubler differs from the known ones in that the primary winding is connected to three single-phase rectifying bridges connected by alternating current to a three-phase group.

Such an embodiment of the doubler allows to increase the amplitude of the secondary voltage and, therefore, reduce the size and weight of the doubler at a constant output power.

FIG. 1 shows the described frequency doubler of the radial design, the general view and section along A-A; in fig. 2 is a diagram of the connection of the primary winding of a doubler with rectifiers.

The frequency doubler consists of an external annular core 1, assembled from electrical steel sheet, and an internal annular core 2. On the inner lateral surface of the core 1, axial grooves a are made around the circumference, in which three-phase primary 3 and secondary 4 windings are placed. The same phase windings 3 and 4 are combined with each other in space by

grooves uj and opposite phases are shifted along the grooves relative to each other by 120el. hail To suppress high harmonics primary) winding 3 is made with a clamp equal to 2/3 of

lung division. The secondary winding 4 anz is logical primary, but it can be made single-layer. The phases of the secondary winding 4 are interconnected in a star or a triangle. Winding 3 and 4 doubler can

be performed with any number of drug poles. The primary winding 3 of the same phase terminals is connected to the same terminals of the rectified current of three single-phase bridge rectifiers 5 connected to each other by alternating current leads into a star or delta. The active parts of windings 3 and 4, which are located in grooves a, are enclosed in slot insulation 6, and the frontal parts - in frontal insulation 7.

A three-phase static frequency doubler can also be designed with an end structure. In this case, the annular magnetic circuit is wound with electrical tape and consists of two coaxial annular cores joined by end surfaces. One of the cores on the end surface facing the other core has radial grooves uniformly distributed around the circumference, into which the primary and secondary end windings are laid.

When the three-phase sinusoidal voltage of the supply frequency is connected to the primary winding 3, the phases flow in the same direction relative to the beginning (end) of the phase windings and the pulsating full-wave current varies in time only in magnitude, at a frequency twice the supply frequency, since the phases of the winding are equally connected to three single-phase bridge rectifiers 5. The primary two-layer winding 3 has a pole equal to 2-3 pole divisions and phases shifted along the slots by 120 el. hail, in which the pulsating full-wave currents flow in the same direction relative to the beginning (end) of the phases, creates a resultant magnetizing force rotating around the circumference of the magnetic circuit with a double frequency as compared to the supply frequency. Under the effect of the resultant magnetizing force of the primary winding 3, the resulting rotating magnetic flux arises in the cores 1 and 2 of the doubler, causing the secondary winding 4 ed. with. twice the frequency of the input frequency. The shape of the output voltage of the doubler frequency approaches a sinusoidal one and, therefore, the harmonic content of higher orders in it is insignificant, and there is no constant component in the resulting magnetic flux.

Subject invention

A three-phase static frequency doubler containing an annular magnetic circuit with grooves uniformly distributed around the circumference in which the primary and secondary three-phase windings are laid, characterized in that, in order to reduce the size and weight of the doubler, the primary winding is connected to three single-phase rectifier bridges connected along alternating current.

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(RI2 1

FIG. 2