JPS6321416B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an armature winding in a 4n+2 pole (where n is an integer) three-phase alternating current machine that uses a single-turn half-turn coil to form a well-balanced four-parallel circuit. In general, in the case of an AC machine armature circuit having a multiple parallel circuit configuration, it is required that there be no difference in the phase difference and absolute value of the generated voltage between the parallel circuits, that is, a good balance is required. Now, in the two-layer armature winding of a three-phase alternating current machine, if the number of poles is P and the number of grooves per pole is ab/c (where a, b, and c are integers), each phase A general condition for obtaining a multi-parallel circuit three-phase armature winding in which each parallel circuit is perfectly balanced is that the number of parallel circuits is a divisor of P/c. For this reason, it has been difficult to obtain a number of parallel circuits other than a divisor of P/c with good balance using conventional wiring connections, so depending on the number of poles, the degree of freedom in design is limited. It was very restricted. For example, if the number of grooves per pole is an integer, 1, 2, 3,
4, 6, and 12 parallel circuits can be selected (parallel circuit 1 is not actually parallel, but it will be considered a special case of parallel. The same applies to the following), whereas the 14-pole machine has 1, 2, and 7 parallel circuits. , only 14 parallel circuits can be selected,
The drawback was that the number of circuits near the 4-parallel circuit, which is optimal for 250MVA class large capacity machines, could not be selected. In other words, a large capacity of 150 to 350 MVA class generally uses a single-turn half-turn type wound coil.
In a 14-pole synchronous generator, if you can choose the number of parallel circuits per equivalent to 4, the rated voltage, rated current, electromagnetic load, and number of grooves will be appropriate values, and the synchronous generator itself In addition, it is often advantageous in designing and manufacturing other electrical equipment in the plant that is connected to the phase separation bus, including the phase separation bus. In a three-phase alternating current machine, if n is an arbitrary integer,
It is classified into two types: 4n pole machine and 4n + 2 pole machine,
If the number of grooves per pole is an integer in a 4n pole machine,
A perfectly balanced 4-parallel circuit armature winding can be easily obtained using conventional wiring methods, but in the case of a 4n + 2-pole machine, special measures were required to select a 4-parallel circuit. . The present invention uses an ordinary single-turn half-turn winding coil in a 4n + 2-pole 3-phase AC machine, and when the number of grooves per pole and 1 phase is an even number, a 4-parallel circuit 3-phase armature with good balance is applied. The purpose is to provide winding wire. In the present invention, first, the phase to which each coil belongs is determined for each electrical angle of 1/3π, as in the conventional case of ordinary winding. Now, if the total number of grooves is N, the number of single-turn half-turn winding coils is 2N because it is a two-layer winding, and this number is distributed to each phase by 1/3, so it is equivalent to 1. The number of pieces is 2/3N. Divide this by the number of parallel circuits per circuit, 4, to find the number of 1/6N circuits in a series, and use this as one group. At this time, the half-turn coils housed in the grooves have different electrical angles depending on their positional relationship with the magnetic poles, so if they are connected in series, the voltage generated in each group of circuits will vary depending on the half-turn coil. Since this is the sum of the vectors of the voltages generated in the coils, the coil groups are configured and connected to four parallel circuits so that the vector difference in the sum voltage for each group is minimized. Hereinafter, one embodiment of the present invention will be described with reference to FIG. This is a half-turn coil that belongs to one phase of a full-pitch armature winding with 252 grooves, 14 poles, 3 phases, 6 grooves per pole, and a short knot ratio of 100%. Vector of voltage generated in each line A ₁ to _{A 6}
This is an illustration. Generally speaking, if the number of grooves per pole is q, then as mentioned above, the electrical angle of a half-turn coil varies depending on the positional relationship with the magnetic pole. There are 3q types of half-turn winding coils, and when the short section ratio is 100%, it is sufficient to consider q types of vectors per one. Therefore, the number of half-turn coils with the same electrical angle is 2N/3q. Applying this to the one in Figure 1, since q = 6, there are six types of vectors, A ₁ to _{A 6} , and the phase difference between each vector is π/18, which means that the electrical angle is the same. Since the number of turn-wound coils is 28 since 2N/3q=28, the absolute value of each vector A ₁ to _{A 6} in Figure 1 is
28 times more. That is, in order to obtain a perfectly balanced 4-parallel circuit, when selecting 1/4 of the number of half-turn winding coils of each vector A ₁ to A ₆ , 28
Since the number of books is 7 times 4, select 7 books at a time and connect them into a series. At this time, if the product of the number of poles P and the number of grooves per pole is not a multiple of 4, the winding will not be balanced, but in a 4n+2 pole machine such as 14 poles, dividing the number of poles by 2 will result in an odd number. Therefore, it is necessary that the number of grooves per pole be an even number.
According to this embodiment, if the voltages of the vectors A ₁ to _{A 6} are V _A1 , V _A2 , ..., V _A6 , the voltages of each parallel circuit are all 7 (V _A1 + V _A2 + V _A3 + V _A4 + V _A5 +
V _A6 ), the voltage and phase of each parallel circuit are equal, and no circulating current flows between the parallel circuits. In this way, if the short section ratio is 100%, the two layers stored in the groove, that is, the upper coil and the lower coil, are always in the same phase, so the number of grooves q and the number of poles P per one pole are
A perfectly balanced four-parallel circuit three-phase armature winding is obtained irrespective of the value of . Next, as another example, in a synchronous machine that generally uses a single turn coil, the armature winding is changed to a short pitch winding, which has the advantage of removing harmonics and improving the voltage waveform. Since there are many cases, this case will be explained. When short-pitch winding is used, the phase of the upper coil and lower coil housed in the same groove are different from each other depending on the determined short-pitch ratio β (β is expressed in radians) of the winding. The number of grooves in this out-of-phase coil is determined by the following equation. Number of grooves in different-phase coils = 2 x 3Pq (1-β/π) In other words, the number of half-turn winding coils in which one-phase upper and lower coils are housed together with different-phase lower and upper coils is {3pq (1-β/π)} In this book, there are also {q+3q(1-β/π)}=m types of vectors with different electrical angles of the voltage generated in the half-turn wound coil forming one phase. Become. Figure 2 is the same as Figure 1, with 252 grooves, 14 poles, and 3 phases.
FIG. 2 is a vector diagram of voltage generated in a half-turn coil belonging to one phase of an armature in which the number of grooves per pole is 6 and the short section ratio β=17/18π. The difference in electrical angle between each vector is π/18 as in FIG. 1.
It can be seen that there are seven types of vectors with different electrical angles by substituting q=6 and β=17/18π for {q+3q(1-β/π)}=m. That is, it becomes a vector of A ₁ to _{A 7} . As shown in Figure 3, A ₂ of these
~A ₆ vector is half-turn type winding coil ₂ where the upper coil and lower coil are housed in the same phase.
The vector of voltages generated at ~ ₆ , upper coil 14
The main coil and 14 lower coils make a total of 28 coils, and the absolute value of each vector is 28 times. However, the vectors A ₁ and A ₇ are vectors of voltage generated in the half-turn coil ₇ placed in the upper coil, and the other is the voltage vector generated in the half-turn coil ₇ placed in the lower coil. Therefore, the number of half-turn type winding coils belonging to electrical angles A ₁ and A ₇ are both 14.
I only have one book at a time. Here, if vector A ₁ in Figure 2 is set at 0 radian, the electrical angle difference between each vector A ₁ to _{A 7} is π/18, so vector A ₂ is 1/18π,
Vector A ₃ is 1/9π, vector A ₄ is 1/6π, vector A ₅ is 2/9π, vector A ₆ is 5/18π, vector
A ₇ becomes 1/3π. Divide this into 4 groups for each phase, 42
I will create a 4-parallel circuit for this series, but now,
If the voltage generated in a half-turn coil of one phase and one circuit is E = ε ^j 〓 (θ is expressed in radians), the generated voltage V of one phase and one circuit is V = ε ^j 〓 ¹ + ε ^j 〓 ² +…+ε ^j 〓 ⁴¹ +ε ^j 〓 ⁴² , and other circuits can be taken in the same way, so to obtain a 4-parallel circuit with good balance, it is enough to compare the generated voltage V of 1 phase and 1 circuit. It is. In addition, since the half-turn type wound coil stored in the groove is a two-layer winding, two of the four circuits can be selected to be completely balanced, but the remaining two circuits have a different voltage level from the previous two circuits. Since the phase differences and absolute values are different, a circulating current will occur between certain parallel circuits. Since the purpose of the present invention is to obtain 4 parallel circuits with good balance, 1/4 of the number belonging to the electrical angle of vectors A ₁ to _{A 7} is connected in series as one circuit, and the distance between the parallel circuits is It is sufficient to minimize the circulating current. The table below shows how many half-turn coils each circuit A and another circuit B should extract from each vector A ₁ to A ₇ , each having an electrical angle of π/18. It is something that

[Table] There are various extraction methods, but the table above shows three of them. Examples of these are (1)
A combination of In other words, this configuration divides the half-turn type winding coils of A circuit and B circuit into 7 coils for each vector of A ₁ to A ₇ and 4 and 3 coils, and 14 coils into 8 coils and ₆ coils. For vectors, 4 wires are assigned to the A circuit, and 3 wires are assigned to the B circuit. Conversely, for A ₂ vectors, 6 wires are assigned to the A circuit, and 8 wires are assigned to the B circuit. For A ₃ vectors, more wires are assigned to the A circuit. 8 pieces,
Assign at least 6 coils to the B circuit, and in the following A ₄ to A ₆ vectors, alternately assign more and less coils to the A circuit and B circuit, and connect them in series to assemble the winding. . The actual coil connection is shown in Figure 3. In this figure, only part of the V phase is labeled as A, B, ₁ , ₂ ,... ₇ , but A,
B indicates the A circuit and the B circuit, respectively. Two circuits each connected to every other pole, totaling 4
The circuits are connected in parallel. ₁ , ₂ ,… ₇ are
A half-turn type winding coil is shown that induces voltages of each vector A ₁ , A ₂ , ...A ₇ . 1, 3 in the diagram
5, . . . 251 indicate only odd numbered slot numbers, and the two unmarked half-turn coils between them indicate even numbered slots. For example, ₁ coil is inserted into slot 248 of A circuit, which induces a voltage of A ₁ vector, and a coil inserted into slot 15 induces a voltage of 2 vectors, A _{2 .}
It is connected to a coil, and _is further inserted into slot No. 32 to induce a voltage of _A1 vector. In the same way, following the V-phase A and B circuits, you will reach outlet Y,
When the vectors of each coil connected between them are counted, it is confirmed that the combinations shown in (1) in the table are obtained, but the following explanation is omitted. However, in order to achieve this combination, for example, when ₄ coils are connected, ₁ coil in slot 104 is connected to 3 coils in slot 124 instead of ₂ coils in slot _123.
Connect to the coil, then connect to _{the 2} coils in the 141st slot, and in the same way, connect _{the 3} coils in the 232nd slot to the ₃ coils in the 250th slot.
When calculating the voltages of circuits A and B in this example, ε ^j 〓 can be converted from Euler's equation as ε ^j 〓 = cos θ + jsin θ, so we calculate the cosine function and sine function, respectively, and compare the difference voltages. Just do it. Here, if the voltage generated by circuit A is V _{A, and the voltage generated by circuit B} is V _B , then in the classification (1) in the table, (V _A − V _B ) ² = (cos0−2cos1 /18π+2cos1/9π−2
cos1/6π+2cos2/9π−2cos5/18π+cos1/3
π) ² + (sin0−2sin1/18π+2sin1/9π−2sin1/6
π+2sin2/9π−2sin5/18π+sin1/3π) ² =0.
00765427. For comparison, we also calculate the combination of (2) and (3) in the table. (2) is (V _A − _{V B} ) ² = 0.192933 (3) is (V _A − V _B ) ² = 0.483173 Therefore, as is clear from this, if circuit A and circuit B have the arrangement of combination (1), the circulating current will be minimized. For this example, the circulating current
Calculating how much flow will flow when 1 ^PU is used, |V _A |≒|V _B |=40, so the differential voltage is |V _A −V _B |/40=0.00218722 ^PU , and the generator If the leakage reactance is xl = 0.12 ^PU , the circulating current Ic is Ic = 0.00218722 ÷ (0.12 x 4 x 2) = 0.00227835 ^PU , which is less than 1% of the armature current, which has no practical problems and has an extremely balanced balance. A four-parallel circuit three-phase armature winding with good quality can be obtained. And the value of short clause rate β is π
The closer to , the larger the values of the number of grooves N and the number of poles P, the better the balance will be in the 4-parallel circuit. That is, the circulating current flowing between parallel circuits is reduced. The above has described the 14-pole machine, but 4n+2
Of course, a well-balanced 4-parallel circuit can be obtained for 10-pole machines, 18-pole machines, etc. by using the above-mentioned technical means. As described above, according to the present invention, in a 4n+2-pole three-phase alternating current machine, in a full-pitch winding with a short-pitch ratio of 100%, regardless of the values of the number of grooves per section and the number of poles,
A perfectly balanced 4-parallel circuit armature winding can be obtained, and even with short-pitch windings where the short-pitch ratio is not 100%, a 4-parallel circuit armature winding with good balance can be obtained. This increases the degree of freedom, and is extremely advantageous in designing other electrical equipment within the plant.

[Brief explanation of the drawing]

FIG. 1 is a vector diagram showing one embodiment of the armature winding of the present invention, FIG. 2 is a vector diagram showing another embodiment, and FIG. 3 is a wiring diagram of the armature winding. A ₁ to A ₇ ... vector, ₁ to ₇ ... vector
Half-turn type winding coil corresponding to A ₁ to A ₇ .

Claims (1)

[Claims] 1 of a 4n+2-pole three-phase AC machine, where 1 n is an integer.
The number of grooves q per pole is selected to be an even number, and the armature winding is wound in two layers using a single-turn half-turn coil, and the coils housed in each groove are divided into three phases. The voltage vectors become {q+3q(1-β/π)}=m types due to the short node ratio β.The voltage vectors of the coils to be connected to the same phase are A ₁ , A ₂ ,
..., A _n , and the coils ₁ , ₂ , inducing these,
..., taking _n every other pole, if 3q(1-β/π) is 1, there will be ₁ coil and 2n+1 coils for _n , so divide each into 2 groups of n+1 and n coils,
A ₂ , ₃ ,..., _n-1 coils are each 4n + 2, so divide each into 2 groups of 2n + 2 and 2n,
A ₁ coil is n + 1, ₂ coil is 2n, ₃ coil is 2n + 2, ₄ coil is 2n, etc. ₁ coil is taken more, then ₂ coils are taken less, ₃
Take many coils, then alternately take more or less coils with the same vector, connect them in series to form one circuit, and connect the remaining coils in series to form another circuit. Similarly, the coils installed at every other pole are divided into two groups, each forming one circuit. If 3q (1-β/π) is 2, then ₁ , ₂ coils and _n-1 , _n Since there are 2n+1 coils each, divide each into two groups, n+1 and n, ₃ ,
A ₄ ,..., _n-2 There are 4n + 2 coils each, so divide them into 2 groups of 2n + 2 and 2n, repeat alternately with more or less coils with the same vector, and connect them in series. Connect the remaining coils to form one circuit, connect the remaining coils in series to form another circuit, and connect the remaining coils to every other pole to form two circuits.
An armature winding characterized in that each circuit is configured in a similar manner and connected to four parallel circuits even when 3q (1-β/π) is 3 or more.