RU61486U1 - COMPRESSION GENERATOR LOAD EXCITATION AND POWER SUPPLY DIAGRAM - Google Patents

Abstract

The utility model is aimed at reducing the dimensions of the excitation system, reducing the power of the excitation source and increasing the reliability of the generator. The specified technical result is achieved by the fact that the direct voltage excitation source is connected in parallel with the generator rotor winding with sliding contacts, and the load and the semiconductor diode are connected in series with the generator stator winding so that the current in the rotor winding and the sliding contacts is equal to the sum of the excitation source and load currents . Fig. one.

Description

The utility model relates to the field of parametric type electric machine generators with the total inductance of two identical and inductively coupled windings of the rotor and stator periodically changing as the rotor rotates and can be used to power electrophysical installations with periodically repeating unipolar current pulses.

The known scheme of excitation and load power of the compression generator [Glebov I.A., Kasharsky E.G., Rutberg F.G. Short and shock synchronous generators. - L .: Nauka, 1985, p.202-204], in which the excitation source and the load with the switch are connected in parallel with two identical and inductively connected windings of the rotor and stator of the generator, which are connected in series by means of sliding contacts (contact rings and brushes ) When the rotor rotates, the total inductance of these windings periodically pulsates due to the fact that in one position of the rotor, the windings turn on according to and have a maximum total inductance, and in the other, they meet and have a minimum total inductance. At the moment of maximum total inductance of the generator windings, the switch connects the load in which the current pulse is generated, and then, after the current decreases, this switch disconnects the load.

The disadvantages of this scheme when generating periodically repeating current pulses are the need to use a powerful pulsed excitation source, a periodically operating switch and the fact that the insulation of the rotor winding and sliding contacts, calculated on half the generated voltage, is subject to significant mechanical and thermal loads - all this reduces reliability and efficiency generator work.

The closest technical solution is a circuit with a source of excitation of a constant voltage, selected as a prototype [But D.A. Contactless electric machines. - M: Higher School, 1985, p.208]. This circuit contains

serially connected generator windings with a total variable inductance, in parallel with which a direct voltage excitation source with a ballast inductance of an additional coil and a load with a semiconductor diode are connected. Ballast inductance serves to limit the ripple of the excitation current and is also used so that the excitation source does not bypass the load, and the diode is needed to separate the circuits of the flow of excitation currents and load. With a periodic change in the total inductance of the generator in the load, unipolar current pulses periodically repeated with a frequency of change in the inductance of the generator occur.

The disadvantage of the prototype is the significant ballast inductance of the additional coil, commensurate with the maximum total inductance of the generator windings, which leads to increased dimensions of the excitation system and power loss in the resistance of the additional coil. The insulation of the rotor winding and sliding contacts is affected by half of the generated voltage, which reduces the reliability of the generator.

The objective of the utility model is to reduce the dimensions of the excitation system, reduce the power of the excitation source and increase the reliability of the generator.

This is achieved by the fact that in the load excitation and supply circuit of a compression generator containing a constant voltage excitation source, a load connected in series with a semiconductor diode, and two identical inductively connected generator windings located on the rotor and stator and interconnected by means of sliding contacts, a constant voltage excitation source is connected parallel to the winding of the generator rotor with sliding contacts, and the load and the semiconductor diode are connected subsequently atelno a generator stator winding so that current in the rotor winding and sliding contacts was equal to the sum of the excitation source and the load currents.

The achieved result will be explained for an implicit pole compression generator with constant inductances of the generator windings L and very small resistances of the generator windings and sliding contacts R ₁ and R ₂ , when these resistances can be neglected when determining the laws of change of currents. We assume that the mutual inductance of the generator windings during rotation of the rotor periodically changes in time t according to the harmonic law

M (t) = kLcosωt,

where k <1 is the coupling coefficient of the rotor and stator windings;

ω is the angular frequency determined by the rotor speed and the number of pole pairs of the rotor winding (stator).

The flux linkage of the rotor windings (ψ ₁ ) and the stator (ψ ₂ ) will be equal

In idle mode, when the load current is zero, we determine the constant excitation current and the power of the excitation source

and also the voltage at the load, which due to the diode is greater than or equal to zero:

where U ₀ is the constant voltage of the excitation source.

In the short circuit mode, when the voltage at the load is zero, from the solution of the equations

we find the excitation current and the average power of the excitation source

as well as load current

Where

Thus, the semiconductor diode provides the generation of unipolar current pulses in the load and prevents the passage of the excitation current through the load. The highest values of the excitation current and the power of the excitation source correspond to the idle mode, and the circuit feature is such that the load current through the excitation source does not pass to the highest value of this current in the short circuit mode

corresponds to the lowest value of the excitation current

The inventive utility model has the following advantages over the prototype:

1. Due to the absence of an additional coil with ballast inductance, the dimensions of the compression generator excitation system are reduced.

2. Due to the lack of an additional coil and to reduce the ripple of the excitation current, the power of the excitation source decreases.

3. By connecting the excitation source parallel to the rotor winding with sliding contacts, the reliability of the generator increases, because the insulation of the rotating rotor winding and sliding contacts is calculated only for a small constant excitation voltage, and the insulation of the fixed stator winding is calculated for the entire generated voltage.

Figure 1 shows a diagram of the excitation and power load of the compression generator. The circuit contains a direct voltage excitation source 1, which is connected parallel to the winding of the generator rotor with sliding contacts, having inductance (L) 4 and resistance (R ₁ ) 5. The load of generator 2, connected in series with the semiconductor diode 3, is connected in series with the stator winding of the generator having inductance (L) 6 and resistance (R ₂ ) 7, so that the current in the rotor winding and the sliding contacts 4, 5 is equal to the sum of the currents of the excitation source i _B (t) and the load i _H (t). The same inductances of the generator windings 4 and 6 are characterized by the mutual inductance M (t).

The excitation and power supply circuit of the compression generator operates as follows. The current i _B (t) of the direct current excitation source 1 and the current i _H (t) of the load 2, flowing through the rotating winding of the rotor with sliding contacts 4, 5, generate, due to the mutual inductance M (t), an alternating voltage across the stator winding 6 , 7. Under the action of this voltage and semiconductor diode 3, unipolar current pulses i _H (t) are generated in load 2, and due to the semiconductor diode 3 and the sum of currents i _B (t), i _H (t) in the rotor winding and sliding contacts 4, 5, the excitation current i _B (t) does not flow through load 2.

The utility model in comparison with the prototype based on calculations and experimental studies conducted by the author has, in idle mode, approximately two times more excitation current and two times less power source

excitations with significantly smaller dimensions of the excitation system. In this case, the voltage of the excitation source applied to the rotor winding with sliding contacts is ten times less than the generated voltage on the stator winding.

This utility model is implemented in the form of a load excitation and power supply circuit of an implicit pole compression generator weighing 500 kg with three pairs of poles and 33 revolutions per second of the rotor for pulse-periodic power supply of the active-inductive load. This generator has an average excitation source power of 600 W with an average generated power of 60 kW and a current pulse repetition rate of 100 Hz.

Claims (1)

The load excitation and power supply circuit of a compression generator containing a direct voltage excitation source, a load connected in series with a semiconductor diode, and two identical inductively connected generator windings located on the rotor and stator and interconnected by means of sliding contacts, characterized in that the excitation source DC voltage is connected parallel to the rotor winding of the generator with sliding contacts, and the load and the semiconductor diode are connected in series with no stator coil of the generator so that the current in the rotor winding and sliding contacts was equal to the sum of the excitation source and the load currents.