RU2095923C1 - Synchronous electric motor with integral multifunctional exciter without brushes - Google Patents

Abstract

FIELD: electric engineering. SUBSTANCE: magnetic system of inductor of exciter has poles with electromagnetic and combined excitation. Poles with combined excitation have alternating polarity and are located in symmetry around inductor axis. Slots of pole pieces with combined excitation contain two coils of different pitch. Pitch of one coil is identical to pitch of coils in integral armature winding of exciter which is located in slots of pole pieces with electromagnetic excitation. Pitch of second coil is equal to even number of pole pitches in working harmonics of tooth order of generated field in air gap. Armature winding of exciter has at least one parallel arms which maximal number is equal to number of poles with combined excitation. Slots of lesser depth which are filled with said winding are located between slots which are filled with armature winding of exciter. EFFECT: simplified design, increased efficiency. 2 cl, 2 dwg

Description

 The invention relates to electrical engineering and can be used for brushless excitation of synchronous machines.

 A device is known consisting of a synchronous generator, a synchronous exciter of a reversed design, an exciter, structurally designed as a separate electric synchronous machine with magnetoelectric excitation, and an automatic excitation regulator [1] The excitation winding of the exciter through a static converter is connected to the terminals of the anchor winding of the preheater. The anchor winding of the pathogen through a rotating transducer is connected to the excitation winding of the synchronous generator. Automatic excitation regulator (ARV) receives power from the anchor winding of the exciter.

 A disadvantage of the known design is the presence of three electric machines made in different magnetic systems and located on the same shaft, which lengthens the unit, makes the manufacturing and operation of the device more expensive and complicates.

 The closest solution, chosen as a prototype, is a device that consists of an excited synchronous machine (generator) of synchronous excitation of a reversed structure with an m-phase anchor winding and clearly defined poles, in the grooves of the tips of which are placed the winding and synchronous exciter of the inductor type [2] Field excitation of the inductor exciter is the tooth harmonic of the resulting field in the air gap of the synchronous pathogen. The winding and the tooth zone of the pathogen armature are constructed in the traditional manner [3] In the device under consideration, the process of initial self-excitation is carried out due to the presence of a residual field in the magnetic material of the inductor.

 The main disadvantages of the prototype are.

 1. Non-guaranteed time of the process of self-excitation, because residual flow rate is not guaranteed.

 2. A wide range of changes in the output voltage of the exciter when changing the mode of operation of the pathogen from the initial self-excitation to forcing excitation. And in the case when the automatic excitation regulator / ARV / receives power from the anchor winding of the exciter. This leads to an increase in the rated power of the ARV power supply in comparison with the case of powering the regulator from an independent DC voltage source.

 3. The dependence of the time of the self-excitation process on the ratio of the selected value of the exciter voltage in the nominal mode and the threshold voltage of the static semiconductor converter.

 4. The absence in the exciter of the current sensor of the armature winding, necessary for regulating the excitation current of the exciter using ARV.

 The objective of the invention is to improve the dynamic characteristics of a complex consisting of a synchronous machine and a modern multifunctional pathogen while reducing material consumption and increasing efficiency, eliminating the disadvantages of the prototype.

 The goal is achieved in that the magnetic system of the exciter inductor consists of poles with electromagnetic and combined (magnetoelectric and electromagnetic) excitation, and the number of poles with combined excitation is an even number, in addition, the poles with combined excitation are made of different and alternating polarity and are located symmetrically around the circumference inductor, and in the grooves of the tips of the poles with combined excitation placed two coils with different steps, one of these coils filled with the same step as the step of the poles of the tips of the poles with electromagnetic excitation, the second of these coils is made in increments of an even number of pole divisions of the working harmonic of the tooth order of the resulting field in the air gap, the anchor winding of the pathogen has one or more parallel poles in the combined excitation, and between the grooves filled with the anchor winding of the pathogen, grooves of smaller depth are made, unfilled with the specified winding. It is possible that the coils placed in the grooves of the pole tips with combined excitation and having a step that is a multiple of an even number of pole divisions of the working harmonic of the transverse order of the resulting field in the air gap are connected in series according to the coils placed in the grooves of the pole tips with combined excitation and made with the same step as the step of the coils in the tips of the poles with electromagnetic excitation, are also connected in series according to.

 In FIG. 1 and 2 show a combined multifunctional exciter of a synchronous machine and a schematic diagram of a synchronous machine with a combined multifunctional brushless exciter made as a separate electric machine in the same housing with it or cantilevered.

 In FIG. 1 is a cross-sectional view of a combined multifunctional brushless pathogen. The magnetic system 1 of the exciter inductor consists of poles with electromagnetic 2 and combined (electromagnetic and magnetoelectric) 3 excitation. The number of poles with combined excitation is an even number. These poles are made of different and alternating polarity and are located symmetrically around the circumference of the inductor. Permanent magnets 4 are placed at the poles with combined excitation. An excitation winding 5 is available at all poles. In the grooves of the tip of each pole with electromagnetic excitation placed two coils 6 with equal steps. These are coils, connected in a known manner into phases, form a combined anchor winding of exciters. In the grooves of the pole tips with combined excitation, two coils with different steps are laid. One of the coils 7 is made with the same step as the coil of the anchor winding of exciters. The second 8 is performed with a step that is a multiple of an even number of pole divisions of the working harmonic of the tooth order of the resulting field in the air gap. All coils 7 are interconnected in series according to. All coils 8 are likewise connected in series according to.

 The anchor winding 9 of the pathogen, laid in open slots, has one or more parallel branches, the maximum number of which is equal to the number of poles with combined excitation. Between the grooves filled with the anchor winding of the pathogen, grooves of at least depth 10 are performed, unfilled with the specified winding.

 In FIG. 1, the number of poles with a combined excitation of the example is taken to be two. They are made of different and alternating polarity / N, S /. The winding of the pathogen anchor in this case may have one or two parallel branches. You can perform an inductor, for example, with twelve poles, four of which are combined excitation. The last poles should be symmetrically located around the circumference of the inductor with alternating / N, S, S, N / polarity. In this case, the winding of the armature of the pathogen can be performed, if necessary, with four parallel branches. And four is the maximum possible number of parallel branches.

 In FIG. 2 shows a diagram of an electrical excitation system, for example, consisting of a synchronous generator with a combined multifunctional brushless exciter. The anchor winding 9 of the pathogen through a rotating semiconductor converter 11 is connected to the excitation winding of the synchronous generator 12. The combined anchor winding 6 of exciters through the static converter 13 is connected to the excitation winding 5 of the pathogen. The windings 7 and 8 are connected to the ARV 14. The winding 7 performs the function of the ARV power source, and the winding 8 of the current sensor of the exciter armature winding.

 The device (Fig. 1) works as follows.

Let the exciter current and the exciter arm current be zero. The flow at the poles 3 with combined excitation created by permanent magnets 4 and is equal to f $\genfrac{}{}{0ex}{}{\text{°}}{\text{NS}}$ . When the armature of the pathogen rotates, the flow Ф $\genfrac{}{}{0ex}{}{\text{°}}{\text{NS}}$ induced in the anchor winding of the pathogen 9 EMF e $\genfrac{}{}{0ex}{}{\text{°}}{\text{NS}}$ . Under the influence of this EMF and using a rotating diode converter 11 (Fig. 2), an excitation current i _fns flows in the excitation winding of the excited synchronous generator. Let the number of pole pairs of the exciter and the parameters of the permanent magnets be chosen so that the value of this current i _fns is, for example, 30% of the excitation current of the idle speed of the synchronous generator. Then i _fns is the minimum steady-state value of the excitation current of the synchronous generator in the case when, for example, the ARV fails and the excitation current of the pathogen becomes zero.

, где p число пар полюсов возбудителя, D диаметр якоря.When, for example, a sinusoidal current flows through a symmetrical armature winding of the pathogen, the latter creates an MDS reaction of the armature, which, as you know, can be represented as the sum of the first and highest harmonics of the MDS sinusoidal shape with numbers ν. For example, with the number of phases of the armature winding of the pathogen m 4 and the number of grooves per pole and phase q 1, the MDS curve of the armature reaction can be represented by a number of harmonics with odd numbers:
n 1, 3, 5, 7, 9, The indicated MDSs will create fields with the numbers of pole pairs n _p and pole division

, where p is the number of pole pairs of the pathogen, D is the diameter of the armature.

Let each coil of the combined anchor winding of exciters be performed with a step y ≠ 2τ _ν • n, where n is any number of the natural series, starting from one. We take n 3, n 1, i.e. the coil is made with a step y ≠ 2τ ₃ . Then the field created by the third harmonic of the MDS reaction of the pathogen induces in the anchor winding of the exciters the EMF e _a proportional to the load current of the pathogen. Further, we will call e _{a the} asynchronous component, and the combined exciter is asynchronous. If the static Converter 13 (Fig. 2) is open and e _{a is} greater than the threshold voltage of its valves, then under the influence of this EMF, a current will flow in the excitation winding 5 of the pathogen. The parameters of the exciter armature winding, the combined exciter armature winding and the excitation winding can be selected so that the self-excitation of the pathogen will be implemented in the same way as in a DC machine with sequential excitation.

где K 1, 2, 3, Если шаг катушки совмещенной якорной обмотки подвозбудителей выбран так, что y ≠ 2τ_z•n, то зубцовая составляющая результирующего поля в зазоре возбудителя наведет в ней ЭДС e_u. Эту составляющую ЭДС, пропорциональную результирующему полю в зазоре и вызванную наличием зубцов якоря возбудителя, будем называть индукторной ЭДС, а совмещенный подвозбудитель индукторным. Гармонику поля, которая наводит индукторную ЭДС, будем называть рабочей гармоникой зубцового порядка результирующего поля в воздушном зазоре. Если параметры якорной обмотки индукторного подвозбудителя, зубцовой зоны якоря и обмотки возбуждения возбудителя выбрать соответствующим образом, то может быть реализован режим самовозбуждения. Процесс самовозбуждения происходит также, как в машине постоянного тока параллельного возбуждения. Для его осуществления должны быть выполнены те же условия, что и в машине постоянного тока.As shown above, the anchor of the pathogen is performed with open grooves. This leads to the appearance of “dips” in induction in the resulting field of excitation. The magnitude of the dip depends on the ratio of the width of the groove of the anchor to the size of the air gap. The resulting induction curve in the gap can also be arranged in a row, and tooth-harmonics with the number of pairs of poles Z and pole division are highlighted.

where K 1, 2, 3, If the step of the coil of the combined anchor winding of the exciters is chosen so that y ≠ 2τ _z • n, then the tooth component of the resulting field in the path of the pathogen will induce the emf e _u in it. This component of the EMF, proportional to the resulting field in the gap and caused by the presence of teeth of the armature of the pathogen, will be called the inductor EMF, and the combined exciter is induction. The harmonic of the field that induces the induction EMF will be called the working harmonic of the tooth order of the resulting field in the air gap. If the parameters of the anchor winding of the inductor exciter, the tooth zone of the armature and the excitation winding of the pathogen are selected accordingly, then the self-excitation mode can be implemented. The process of self-excitation occurs in the same way as in a DC machine of parallel excitation. For its implementation, the same conditions must be met as in a DC machine.

In order to reduce the consumption of materials on the anchor winding of exciters and the magnetic circuit of the pole piece between the grooves filled with the anchor winding of the pathogen, grooves 10 (Fig. 1) of smaller depth are filled, not filled with the specified winding. This allows you to get an additional induction dip in the inductor field and thereby increase the EMF e _u , and, therefore, with the same given EMF value, reduce the number of turns and groove sizes of the combined armature winding of the inductor exciter, i.e. reduce the consumption of materials on the exciter device.

As noted earlier, it is proposed to use an anchor winding of exciters for ARV supply, the output voltage of which during the operation of the pathogen from idle to forced can vary by fifty or more times. In the proposed device (Fig. 1), the ARV power source is coils 7, made in the same step as the coils 6 of the anchor winding of exciters, and placed in the grooves of the pole tips with combined excitation. The voltage variation range in the coils 7 is much smaller than in the coils 6. So in the case when the flux Φ $\genfrac{}{}{0ex}{}{\text{°}}{\text{NS}}$ , for example, for a pathogen with the number of pole pairs 2p 10, it is equal to half the forced flow in the pole with electromagnetic excitation, the voltage in the coils 7 changes less than 3 times. The electromagnetic field winding 5 at the poles with permanent magnets serves to compensate for the reaction of the armature and thereby to reduce the range of voltage variation in the coils 7.

 Note the following. If in FIG. 1 device to divide the permanent magnets of the poles with combined excitation in height by 2p magnets and distribute the latter at the poles, i.e. make all poles with combined excitation, the voltage in the anchor winding of the exciters will change during the operation of the pathogen more than 20 times. Thus, by means of permanent magnets in part of the poles of the pathogen, it is possible to reduce the range of variation of the voltage of the ARV power supply.

 The excitation current of the pathogen is controlled by ARV. As the current sensors of the excitation windings of the generator, they are used in series according to the connected coils 8 (Fig. 1), placed at the poles with combined excitation 3 and made in increments of an even multiple of the even number of pole divisions of the working harmonic of the tooth order of the resulting field in the air gap. The placement of the coils at the poles with combined excitation and their successive consonant connection eliminates the influence of the EMF of the reverse frequency caused by the magnetic asymmetry of the inductor as a result of technological deviations in its manufacture.

 In transient modes of operation of a synchronous generator, for example, in the start-up mode of an asynchronous motor or short circuit, aperiodic and periodic current components occur in the excitation winding of the generator. In relation to the armature of the pathogen, these currents are, as it were, sources of current, causing an increase in the current of the armature of the pathogen, and, consequently, an increase in the EMF of the asynchronous exciter, which ultimately leads to an increase in the frequency of forcing the excitation winding of the pathogen. In this mode of operation of the complex, the power of the asynchronous exciter consists of two parts, namely: the power supplied from the shaft and the power supplied by the transformer from the excitation winding of the synchronous generator through a semiconductor converter and the anchor winding of the exciter. The indicated power is amplified by a synchronous exciter, which ensures an increase in the voltage rise rate on the excitation winding of the synchronous generator. The synchronous generator, as it were, helps the pathogen cope with the transient process in the generator. For comparison, we note that this property does not possess a device, in contrast to the one proposed, consisting of a synchronous generator, a brushless synchronous exciter and a sub-exciter made with excitation from permanent magnets. On the contrary, the transient process in the generator winding reduces the frequency of forcing the pathogen.

 A synchronous generator with a permanent magnet exciter also possesses the aforementioned dynamic quality of "mutual assistance", but the presence of a small residual flux limits the zone of excitation currents at which this effect acts. The introduction of permanent magnets only in part of the poles simultaneously solves two problems: it improves the dynamic performance of the complex and guarantees the stability of this process, and also reduces the range of variation of the voltage of the ARV power supply.

Claims (2)

 1. A synchronous machine with a combined multifunctional brushless exciter, consisting of an excited synchronous machine, a synchronous exciter, asynchronous and inductor exciters combined in one reversed-type magnetic system with the number of pole pairs P> 2 of explicit pole design, the excitation winding is placed on the poles, and in the grooves pole tips combined anchor winding of these exciters, performed in increments of an odd number of pole divisions of the working harmonic of the tooth order result a four-phase anchor winding of the pathogen, made with the number of grooves per pole and a phase equal to unity, characterized in that the magnetic system of the pathogen inductor consists of poles with electromagnetic and combined magnetoelectric and electromagnetic excitation, and the number of poles with combined excitation there is an even number, in addition, poles with combined excitation are made of different and alternating polarity and are located symmetrically around of the inductor, and in the grooves of the pole tips with combined excitation, two coils with different steps are placed, one of these coils is made with the same step as the step of the coils of the combined anchor winding of exciters placed in the grooves of the pole tips with electromagnetic excitation, the second of these the coils are made in increments that are a multiple of an even number of pole divisions of the working harmonic of the tooth order of the resulting field in the air gap, the anchor winding of the pathogen has one or more parallel branches, the maximum number of which is equal to the number of poles with combined excitation, and between the grooves filled with the anchor winding of the pathogen, grooves of smaller depth are made, not filled with the specified winding.  2. The machine according to p. 1, characterized in that the coils located in the grooves of the pole tips with combined excitation and having a step that is a multiple of an even number of pole divisions of the working harmonic of the tooth order of the resulting field in the air gap are connected in series according to, the coils placed in the grooves pole tips with combined excitation and made with the same step as the pitch of the coils of the combined anchor winding of exciters, located in the pole tips with electromagnetic excitation, also inens consistently according to.

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