SU577624A2 - Three-phase frequency multiplier - Google Patents

Description

one

The invention relates to frequency converters, in particular to transformer type multipliers, and can be used for induction heating, welding, in rectifying installations, for powering magnetic amplifiers, fluorescent lamps, radio equipment, automation devices, as power sources. electric erosion processing machines, as well as for powering high-speed engines, in particular engines of various tools, trimming machines, etc.

A three-phase frequency multiplier is known, comprising a transformer, on whose terminals there are primary and secondary windings, thyristors and a phase-shifting unit, with four primary windings on each rod, combined in. two pairs, each of which is closed by a pair according to the included thyristors; the common points of connection of the thyristors of the first and second pairs and the windings of the second pair are connected in accordance with the direct sequence of phase alternation to the input phase terminals, and the common connection point of the windings of the first par to the zero input terminal.

The proposed device differs from the known one in that in addition to each phase two counter-connected bias windings and an auxiliary transformer are introduced, the two primary and secondary windings of which are connected in series with the corresponding windings of the main transformer, the primary ones being connected according to, and the secondary one - opposite.

This makes it possible to obtain a quadrupled frequency at the output of the device.

Fig. 1 is a circuit diagram of a frequency multiplier with a single-phase output; figure 2 - diagram of the frequency multiplier with a three-phase output; Fig. 3 shows stress curves.

The frequency multiplier consists of thyristors 1-4, cores 5 and 6, each of which contains primary windings 7.8 ,, bias winding 9 with filter throttle 10 and output windings 11. In addition, the multiplier contains a capacitor 12 for longitudinal capacitive compensation and thyristor control device 13

The device works as follows.

The primary Ujo and linear C voltages are shifted relative to each other: primary by an angle L / 2. The angle between the control pulses of the thyristors 3 and 4 is always 3t.

Due to the shift of the supply voltages UAO hl and angle l, the control pulses of the corresponding thyristors 1-4 are shifted by the same angle.

The principle of increasing the frequency of the input multiplier voltage is discussed below. FIG. The curves are voltage variations, where the position 14 indicates the phase, and the position 15 indicates the linear voltage. When the control pulses are applied to the corresponding thyristor L 1-4, the latter are opened, and voltages arise at the windings of the multiplier with a frequency twice as high as the frequency of the power supply (see Fig. 3b). Simultaneously, by changing the phase of the control pulses supplied from the control unit 13 to the thyristors 1 to 4, the input voltage of the multiplier is adjusted, varying with double frequency relative to the frequency of the power source. The range of adjustment of the control phase, pulses in the first harmonic is from 3/4 to K, i.e. 4t / 4. With an increase in this range, simultaneous operation of several thyristors is possible, which disrupts the operation of the converter.

The output voltage curves shown in Fig. Eb were constructed under the assumption that the thyristors are turned on instantly when control pulses are applied and there is no emf of hygienic induction. The actual output voltage at idle is somewhat different from self-induced self-induced EMF.

Adjusting the input voltage of the multiplier is carried out by simultaneously changing the phase of all the control and the Tulses to the same extent, and if necessary, it is possible to adjust the phase of any control pulse within a small range with special trimming resistors.

The primary windings of the frequency multiplier are connected to the mains voltage: winding 7 to phase, winding 8 to linear, the number of windings 8 to / 3 times more than winding 7, respectively, the current in winding 8 is UG times less than the current in winding 7, what needs to be considered when choosing wire winding sections,

The output windings of the multiplier with a three-phase output can be connected either to a star or to a triangle, therefore, third and multiples of Three harmonics are excluded from linear voltages.

A multiplier with m {phase output (see Fig. 2) includes three multipliers with a single-phase output and its operation is similar to that described above.

Claims (1)

Invention Formula Three-phase frequency multiplier auth.St. No. 549868, differing in the fact that, in order to obtain a quadruple frequency, in addition to each phase were introduced two counter-connected bias windings and an auxiliary transformer, the two primary and secondary windings of which are connected in series with the corresponding windings of the MAIN transformer, and t. primary inclusive according to, and the secondary - the opposite. 0/1,