SU729776A1 - Machine-power diode source of stable frequency three-phase voltage - Google Patents

Description

with respect to the inductor in mutually opposite directions. When the rotor rotates, the EMF induced by these components in the winding of the core differs in frequency and amplitude.

The frequency difference provides for obtaining a modulated voltage in this winding: the amplitude of the resulting emf periodically changes from a value determined by the sum of the amplitudes of the emf to a value equal to the difference of the amplitudes of these emfs. Since the summable emfs have an unequal amplitude, modulation to zero does not occur. The difference of the amplitudes of the summed emf will be, the greater the smaller the ratio of the emf frequency of rotation to the frequency of the excitation voltage, the worse the quality of the voltage curve obtained from the output of the considered device will be.

The aim of the invention is to reduce mass-dimensional parameters and improve the shape of the output voltage curve.

This is achieved by the fact that the generator is made in the form of two asynchronous frequency converters, the rotors of which are rigidly connected to each other, the three-phase root winding of one of the converters is connected to zero points of three three-phase core windings of the other, the outputs of these windings are aligned with the inputs of semiconductor switches, with one of the phases of the first main winding connected to the first input of each switch, the second main winding is shifted to the second input, and to the third phase of the third crust winding is shifted by 240, the three-phase excitation winding of one of the synchronous converters is connected to a fixed frequency source with a reverse phase alternation with respect to the excitation winding of another asynchronous converter.

The drawing shows a functional diagram of the machine-valve source.

The machine-valve source consists of an asynchronous 1 frequency converter with one three-phase horse winding and an 2-frequency asynchronous converter with three three-phased root windings. Structurally, the converters are combined in one package. The armature windings of converter 2 are connected to POWER semiconductor converters 3, 4 and 5.

The rotor packages of the transducers are rigidly connected to each other, the transducer windings are made on the same number of poles.

The purpose of asynchronous converters is to generate three three-phase modulated voltages, while rounding the amplitudes of the voltage curves of each system must be shifted relative to each other by 1/3 of their period. To this end, the windings of the converter rotors are fed with a three-phase alternating current of stable frequency, the alternation of voltage phases at the terminals of the windings is chosen so that the direction of rotation of the field of excitation in one converter coincides with the direction of rotation of the rotor, and in the other it would be opposite; The winding of the converter core 1 is made according to the type of the conventional windings of three-phase AC machines and is connected in stars or a triangle. The winding of the core of the converter 2 is made of three identical, laid in the same grooves, systems of three-phase windings, while the windings within each system are connected in a star. The terminals of the windings of the core of the converter 1 are connected to the zero points of the three-phase windings of the core of the converter 2.

Machine-valve source works as follows.

The drive windings of the transducers are supplied with a sinusoidal alternating current of stable frequency. The transducers are designed so that when they rotate, the frequency of the EMF induced in the core windings is several times higher than the frequency of the current fed by the excitation windings. In addition, excitation transducers of the transducers are connected so that the directions of rotation of the magnetic fields they create are mutually opposite. In the windings of the core of the converters, an emf is induced, the frequency difference of which does not depend on the speed of rotation of the shaft and is equal to twice the frequency of the excitation current.

The windings of the core of the converter 1 are connected in series with the windings of the core of the converter 2, therefore the resulting EMF curve acting in the circuit composed of the windings of the converters 1 and 2 is determined by the sum of the instantaneous values of the EMF curves of these windings .. Due to the fact that the frequencies of the summable EMF differ, the resulting emf is amplitude modulated, and the frequency of the change in the amplitude envelope of the modulated voltage is also equal to twice the frequency of the excitation current.

The phase of change in the envelope is determined by the initial phase angle of the summed EMF. The phase angles between the EMF of the OA winding and the EMF of the OA winding, the EMF of the OA winding and the EMF of the winding, the EMF of the OA winding and the EMF of the winding are different for 1 / period of the EMF of the converter 2, as a result of which the envelopes of the amplitudes of the resulting EMF of OA-O.A circuit, OA-OI Bi, OA-OiCi

are shifted relative to each other by 1/3 of the envelope period

Ms due to the spatial shift of the EMF axis of the OM winding remains from the EMF of the OA winding during the I / O period, the EMF of the winding also lags by 1/3 of the period, and the EMF of the OJ BI winding lags behind. For this reason, the resultant emf of the OB-OBj circuit. lags behind the resulting emf by 1/3 of their period, while the envelopes of the amplitudes of the resulting emf practically coincide. For similar reasons, the resulting emf of the circuit lags behind in phase from the resulting emf of the OA-OA circuit by 2/3 of the period, the envelopes of the curves coincide.

Thus, in the OB-OBg, OC-O, C2 circuits, a first three-phase; EMF system is modulated along a single envelope curve.

Similarly, in circuits, ОV-Og C2, OS - O., A, a second system of three-phase electromotive forces is generated, modulated so that the envelope amplitudes are shifted relative to the envelope of the first system by 1/3 of its period, and in circuits OA-Oj., Cj , OB-OjAg, OC-O2, B2, is the third system of three-phase EMF, the envelope of which amplitudes are shifted relative to the envelope of the first system by 2/3 of the period.

The terminals of the windings of the converter 2 are connected to a semi-expansion converter assembled on the basis of three three-phase reversible rectifiers. The reversing of the voltage of the switch is realized: at the moments of minimum -. the voltages of the corresponding three-phase system. Thus, at the output of the converter, a three-phase voltage is obtained with a frequency equal to half the frequency of the change in the curve, the envelope of the amplitude of the modulated voltage (or, which is the same, equal to the frequency of the excitation current.

Powering a semiconductor converter from three three-phase modulated emf systems allows a three-phase voltage to be obtained in a form that is close to a sinusoidal one without using a relatively variable converter control system and using bulky output filters. Receiving Deployed Modulation Depth or

its adjustment in the device is not associated with any difficulties and is achieved by appropriate selection of the ratios of the turns of the windings of the core; Converters 1 and 2, the ratio of the numbers of the turns of the excitation windings or the ratio of the currents of these windings.

Claims (2)

1. Koroban N.T. Power supply aircraft. M., Mechanical Engineering, 1975, p. 207, fig. 10.8. 2. Sitnik N.Kh., Sylowa Semiconductor Technique, M., Energia 1968, p. 287, fig. 6-1a. 3 Bruskin D.E. Generators excited by alternating current. M., Yoshyscha School 1974, p. 21, Fig. 1.13.   . -f / I h itf f f four-.- . -0 -0