Synchronous-machine rotor, primary for brushless self-excited single-phase synchronous generators

Abstract

The invention is for the rotor of a synchronous machine, especially for the rotor of self-excited single-phase, brushless and regulatorless synchronous generators, which is a laminated, cylindrical, cageless synchronous machine rotor, in the wide teeth (1, 2) of which the small grooves (5, 6) created for this purpose are also wound, and it has a multi-phase damping coil distributed almost evenly around the rotor circumference, with the same number of poles as the excitation coil. The damping coil is connected to the terminals of the excitation coil located under this multi-phase damping coil, in the lower layer of the large grooves (3, 4) outside the wide teeth (1, 2) through a diode bridge.When this rotor is equipped with a stator (11) with a main phase winding and a capacitor auxiliary phase winding, both the magnitude and harmonic content of the main phase winding voltage (U1) remain within a narrow range around the nominal value in the case of an inductive-ohmic load, since the multiphase peak damping coil, together with the negative sequence component of the armature reaction formed in the stator (11) – the “inverse” excitation – produces the excitation current necessary to maintain the voltage of the main phase winding, and the damping excitation rotating with the inverse, nearly equal to it and nearly opposite in direction. ŕ.

Description

The invention relates to a synchronous machine rotor, especially for brushless self-excited, single-phase synchronous generators, which provides excitation sufficient for voltage maintenance, without a regulator, not only in the case of resistive but also inductive loads. This synchronous machine rotor has cylindrical, cageless plates with additional grooves in its wide teeth, with the help of which the rotor circumference is almost uniformly wound with a multi-phase damping coil with the same number of poles as the excitation coil, which is connected to the terminals of the excitation coil located in the lower layer of grooves outside the wide teeth via a bridge-connected rectifier - below this damping coil. The single-phase synchronous generators equipped with a synchronous machine rotor and a capacitor auxiliary phase according to the invention can be advantageously used as generators of universal emergency power sources, for powering motors, welding transformers, and other inductive-ohmic consumers. A close solution is the invention entitled "Improved Single-Phase Synchronous Generator", which is protected by patents in several countries around the world. (In Germany, it is registered under the number DE 33 04 664 Al.) In this solution, the negative sequence component of the armature excitation (the so-called "inverse excitation") generates a pulsating direct current in the excitation coil of the rotor without a damping cage through the diode terminating it, the average value of which is proportional to the armature excitation, so the generator is compounded. At start-up - with the main phase idling - the generator is self-excited due to the interaction of the rotor remanence and the capacitor auxiliary phase. However, as the inductive current of this generator increases and the power factor decreases, the alternating current magnetic conductivity of the excitation coil also decreases, and with it the rectification efficiency, therefore the increase in the negative sequence component of the armature reaction is not followed by the excitation current, and the generator voltage decreases. In several other inventions, a multiphase winding is connected to the excitation winding of the generator via a bridge rectifier. In some of these, this multiphase winding is the winding of another, separate iron-bodied machine (most often an excitation machine) (for example: US 4293810, US 4745315, US 4408152 patents) in other parts, closer to this invention, it is placed in a common rotor iron body with the exciter (for example: US 2966623, US 3676764). Patent description JP 61046149 also includes a generator operating with two winding systems placed in a common rotor iron body. Unlike the present invention, all the solutions mentioned here have in common that in none of them does the multiphase coil perform a damping function, i.e. they are not damping coils: in the former this is precluded by the separate iron body, and in the latter by the fact that the number of poles of the multiphase coil is different from that of the excitation coil. Due to the lack of a damping cage or coil, the voltage of the above single-core generators can be significantly loaded with harmonics, reaching 20-45%, without special equipment or other solutions, which limits their general usability. Thus, there is no general-purpose single-phase synchronous generator that, without brushes, exciter and regulator, would maintain its voltage with harmonic content no higher than the permissible - usually 10% - within a narrow range around the nominal, both with increasing inductive and increasing resistive loads. The invention is based on the recognition that the damping cage, i.e. the short-circuited rotor coil, can be made multifunctional. It can be used not only to prevent and reduce harmonic excitations, but also to produce brushless excitation that is currently sufficient to maintain the voltage of a general-purpose, i.e. inductively loaded, single-phase generator, if it is converted. A multi-phase wound coil with plates evenly distributed around the circumference of a cylindrical synchronous machine rotor, with the same number of poles as the excitation coil, is used instead of the barbed coil, and instead of short-circuiting, the excitation coil is also connected to its circuit via a bridge rectifier. Thus, on the one hand, the inverse excitation and the multi-phase rotor winding - similarly to an excitation machine - ensure, through the rotating rectifier, without slip rings, brushes and control equipment, the excitation current proportional to the negative sequence component of the armature reaction, following it with the smallest possible delay, i.e. the static and dynamic voltage maintenance of the generator, on the other hand, it also functions as a damping coil, since its uniform distribution on the circumference of the cylindrical rotor (a) and its bridge-connected rectification (b) ensure the continuity of the current of the multi-phase coil, its uniformity of magnitude, and the same number of poles as the excitation coil (c) ensures the same number of revolutions of the rotating excitation resulting from the multi-phase current system as the inverse excitation, and these three factors (a, b, c) and the sizing of the rotor windings together ensure that this rotating excitation is almost identical to the inverse excitation. magnitude and nearly opposite direction. In order to achieve the set goal, a multi-phase damping coil with the same number of poles as the excitation coil should be placed in the rotor with cylindrical, high-remanence plates, close to the air gap, and distributed as evenly as possible on the circumference, and connected to the excitation coil placed under the damper through a bridge rectifier. The excitation and damping coils should be sized so that the armature excitation resulting from the currents of the damping coils is in a direction nearly opposite to the inverse excitation, despite the rectifier load. In a possible embodiment of the synchronous machine rotor according to the invention, in the cylindrical plate body consisting of cold-rolled thin plates, the multi-phase damping coil is three-phase, star-connected, one phase of which is located in the small grooves pressed into the wide teeth, and the other two phases are located in the large grooves outside the wide teeth, close to the groove mouth, and is connected through the three-phase diode array placed on the rotor to the winding under the coil, which is located on the wide teeth. HU 222 295 Bl to the terminals of the excitation coil wound first in large grooves. The sizing of the damping and excitation coils, as well as the iron sizes, ensures that this synchronous machine rotor, equipped with the same stator as the stator of the first mentioned above, with the same auxiliary phase synchronous generator with the same rotor length and diameter, achieves the same apparent power - with a smaller capacitor. It produces voltage-holding excitation not only in the case of resistive but also inductive loads, and in the meantime its voltage shape is not distorted to a greater extent than is generally permissible (10%). I will describe the invention with the help of drawings in connection with an embodiment example: Figure 1 is a schematic plate drawing of a possible embodiment of the synchronous machine rotor according to the invention, supplemented with the contour lines of the associated stator plate. Figure 2 is a circuit diagram of a possible embodiment of the synchronous machine rotor according to the invention, shown within the contour line of the rotor plate, supplemented by a circuit diagram of the stator coils shown within the contour line of the associated stator. The possible embodiment presented here as an example is a cylindrical, lamellar, cageless synchronous machine rotor, which includes a wound, star-connected multiphase damping coil T2 with the same number of poles as the excitation coil TI, which is connected to the terminals KI, K2 of the excitation coil TI through 7 diode bridges. The multiphase damping coil T2 in this embodiment is three-phase, i.e. consists of the phase coils FI, F2, F3. In this embodiment, the small grooves 5, 6 in the wide teeth of the synchronous machine rotor 1, 2 are occupied by the phase winding F3 of the multiphase damping coil T2, and the upper layer of the large grooves 3, 4 outside the wide teeth 1, 2 are occupied by the phase windings FI, F2 of the multiphase damping coil T2, so that the multiphase damping coil T2 is distributed almost evenly around the circumference of the rotor, and the excitation coil TI is located below the multiphase damping coil T2, at the bottom of the large grooves 3, 4 outside the wide teeth 1, 2. By rotating the rotor according to the invention in the stator 11 containing the main phase winding 8 (with the same number of poles as the TI excitation winding) and the auxiliary phase winding 9 (also with the same number of poles as them) closed with 10 capacitors, as the speed increases, voltage is induced in the main phase winding 8 and the auxiliary phase winding 9 due to its remanence. If the main phase winding 8 is unloaded, a capacitive current is started in the auxiliary phase winding 9 through the capacitor 10. This creates, on the one hand, an armature excitation rotating in the same direction as the rotor according to the invention, which has the effect of exciting the generator, and, on the other hand, a so-called “inverse” excitation rotating in the opposite direction, at twice the speed, which induces voltage in the TI excitation winding and the T2 multiphase damping winding. When one of the instantaneous line voltages of the multiphase damping coil T2 exceeds the The instantaneous value of the voltage induced in the winding TI, a current starts flowing through the bridge rectifier 7. As a result of the starting rectified winding current, an even higher voltage is induced in the main phase winding 8 and the auxiliary phase winding 9 of the generator, which increases the capacitive current of the auxiliary phase winding 9, i.e. it strengthens the process described here, the generator is excited. During the initial transient processes, an increasingly smoothed rectified current flows in the TI excitation coil, because the 7 diode bridge makes the multiphase alternating current in the FI, F2, F3 phases of the T2 multiphase damping coil more and more continuous, which is achieved by the fact that the T2 multiphase damping coil, due to its identical number of poles as the inverse field, creates an increasingly symmetrical multiphase excitation, a rotating field, rotating with the inverse, but in the opposite magnetic direction, which increasingly counteracts and eliminates the inducing effect of the inverse field in the TI excitation coil. This inverse field compensation also reduces and attenuates the harmonic content of the voltage U1 of the main phase winding of the generator 8 proportionally, since most of the harmonic magnetic fields are generated by inducing the inverse field into the excitation winding TI. After the excitation, when the main phase winding 8 is loaded with an inductive-ohmic load 12, an additional inverse excitation proportional to the current that develops also occurs. This increases the current in the multi-phase damping coil T2, which also causes an increase in the current of the excitation coil TI through the diode bridge 7, which, within given (for example, nominal) load limits and with good sizing, will be the amount necessary to maintain the voltage of the main phase winding 8. The excellent properties of the single-phase synchronous generator with a synchronous machine rotor, a capacitor auxiliary phase and a main phase, without brushes and regulators, stand out in the field of portable emergency power sources, especially when equipment that also consumes reactive current, such as single-phase welding transformers, single-phase motors operating with poor starting or poor operating power factors, also need to be powered. The main advantage of the synchronous machine rotor according to the invention is that it can be used to maintain the main phase voltage of a brushless single-phase synchronous generator with a capacitor auxiliary phase within a narrow range around the nominal value, both statically and dynamically, not only under resistive but also under highly inductive loads, while keeping the harmonic content below a value acceptable to most consumers, without external intervention, regulation or regulator.

Claims

1. Synchronous machine rotor, mainly for brushless, self-excited, single-phase synchronous generators, which is a cageless, plate-like, cylindrical synchronous machine rotor, characterized in that it has a multi-phase damping coil (T2) with the same number of poles as the excitation coil (TI) distributed nearly uniformly around the rotor circumference, which is connected to the terminals (KI, K2) of the excitation coil (TI) via a diode bridge (7).

2. Synchronous machine rotor according to claim 1, characterized in that the multiphase damping coil (T2) is three-phase, star-connected, and its phase coils (FI, F2, F 3) two of the phase coils (FI, F2) together with the excitation coil (TI) are located in large grooves (3, 4), and the third (F3) is It is located in small grooves (5, 6) in 5 wide teeth (1, 2).