JPS589556A - Variable speed drive constant frequency power generation device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a variable speed drive constant frequency power generation device, and particularly to a variable speed drive constant frequency power generation device suitable for a hydroelectric power generation device or the like that has large head fluctuations and large changes in power supply.

In recent years, there has been a demand for the development of a power generation device that constantly controls the speed of the prime mover at an optimal rotational speed depending on the load conditions, which is aimed at hydroelectric power plants and the like where head fluctuations and load fluctuations are severe. The reason for this is, to use the above hydroelectric power plant as an example, to minimize the decline in water turbine efficiency during partial load in the current power generation equipment, which is always operated at a constant rotation speed by a speed governor in response to changes in load conditions. By doing so, it is possible to expand the high-efficiency operation range, and also to reduce the cost of the power generation device by omitting an expensive speed governor having a complicated mechanism.

And: Although it is difficult to implement such a variable-speed drive/excitation generator 1 with the current system that uses a synchronous machine as the generator from the viewpoint of frequency maintenance, it is difficult to implement such a variable speed drive/excitation generator 1 in terms of frequency maintenance. It is known that this can be achieved by excitation of the wire by a variable frequency AC power source at a frequency corresponding to the rotational speed of the prime mover (for example, Japanese Patent Laid-Open No. 52-45
022). Figure 1 shows the typical and basic system configuration.

In other words, this type of conventional variable speed drive power generator has a primary winding (
The prime mover 2 is directly connected to the prime mover 2, which consists of a stator winding) 1a, a secondary winding (1,000 rotations M) 1b, a slip ring 1C, a brush 1d, a rotating shaft 1e+, etc., and the output terminal of the primary winding 1a is opened and closed. 1 to the AC bus 4 through the
A part of the output of the next winding 1a is converted to a predetermined frequency by a frequency converter 6 via a transformer 5, and then the brush 1
d.

Usually, it is connected to the secondary winding via a slip ring IC. In addition, 2a is the rotating shaft of the prime mover 2, 7 is the shaft coupling, and 8 is the rotation a! This is a bearing that rotatably supports I 1 ej 2a.

Next, in the conventional device i1 shown in FIG. The winding frequency f is the primary winding frequency f1
From the condition that it is equal to the difference between the mechanical rotational frequency of the rotor and It is sufficient to constantly excite the secondary winding with alternating current. In this case, it is well known that the effective portion of the secondary winding current, that is, the active power, flows into the winding from the bus bar when the speed is higher than the synchronous speed, and flows out when the speed is higher than the synchronous speed.

By the way, as explained above, the conventional device shown in Figure 1 is effective as a variable speed drive constant frequency power generating device, but the major drawback of this type of power generating device is that
The current collector W1w consisting of a ripple ring and a brush is always required. For this reason, especially when targeting high-voltage machines, not only does maintenance become more complicated, but also the operating speed (or maximum However, if the range is limited, there is also the problem that the advantages of variable speed drive cannot be fully realized.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the drawbacks of the prior art described above and to provide a variable speed drive constant frequency power generation device that does not require slip rings or brushes and is easy to maintain and inspect.

To achieve this objective, the present invention provides an excitation induction machine in place of slip rings and brushes, applies the output of a frequency converter to its fixed primary winding, and applies the output of a frequency converter to its rotating secondary winding. It is characterized by being directly connected to the rotating secondary winding of the machine.

Below is the invention! A detailed explanation will be given based on the illustrated embodiment.

FIG. 2 is an overall configuration diagram of a variable speed drive constant frequency power generation device according to an embodiment of the present invention, shown in correspondence with the conventional example shown in FIG. 1, and the same reference numerals as in FIG. shows.

That is, a wound induction machine 9' (hereinafter referred to as an exciter) is directly connected to the induction machine 1 (hereinafter referred to as the main engine), and its secondary winding 9b
is electrically connected to the main engine 10 secondary winding 1b, and the primary winding 9
8 is connected to a bus bar 4 via a frequency converter 6, a transformer 5, and a switch 3.

・Primary winding 9 of exciter 9 in the embodiment shown in FIG. 2 above
To find the relationship between the frequency of a and the frequency of the primary winding 1a of main engine 1, first of all, for the main engine, here is fMz :main engine 2
Next frequency (Hz) fMl: Main engine primary frequency (HriNR: Prime mover rotation speed (rpm) pl!: For main engine pole number exciter, f12 = fllfl-kuri, standing 60 2...・(3) Here, the relational expression 'Ic2' exciter secondary frequency (H2) PIl, : number of exciter poles is established, and the secondary windings are directly electrically connected, and fK2 = fM2. From, (2) and (6
) expression, fEl ” fMl-j33-・qued (translation)...
...(4) It becomes 60 2. By comparing equations (1) and (4), we can determine the excitation-like primary frequency 'H and main engine primary frequency fM in the example.
1 is the difference in the number of poles between the main pole 1 and the exciter 9 (PM-P8
) has the number of poles, and the exciter primary winding! Secondary winding, main engine 1
It can be seen that one induction machine whose next winding is the 21st winding is 1i11i. Further, although omitted here, the above-mentioned isostatic property also holds true for current, electric power, and width. That is,
The power generation device of this example has characteristics equivalent to a conventional secondary excitation type variable speed drive power generation device using one induction machine, in which the primary @ wire of the exciter is the secondary winding of the main engine, and the equivalent number of poles (PM-P8). It can be seen that there is a By the way, the above explanation is based on the terminal connections of the secondary windings of the main engine 1 and the exciter 9 as shown in FIG.
When M and R□ are connected in the same manner, and when they are connected in opposite phase order as shown in FIG. 4, the relationship of equation (4) is as follows.

f - f - Good 4! 1 ・・・・・・(5)
[I Ml 60 2 and in this case, the sum of the number of poles of the main engine 1 and the exciter 9 (P
It operates as a power generation device equivalent to a conventional brushed quadratic excitation type variable speed drive power generation device using one induction machine with M+P,)y equivalent number of poles.

As mentioned above, it has been stated that the power generation device of the example has the same characteristics and operation as the conventional brushed power generation device using one wound wire induction machine, but since the power generation device of the example uses two induction machines, If this increases the total size of the two units significantly compared to the conventional case of one unit, it is impractical. Next, considering the physique of the generator, the general physique of the induction machine is the same magnetic loading and electrical loading! Assuming that it is proportional to the number of poles, the example of power generation for a conventional power generator (one induction machine) For the same output device, the total physique ratio of the two induction machines of the equipment is the ratio of the sum of the main machine pole number PM and the exciter pole number PIC (total physique of the two machines) to the equivalent number of poles, and the physique ratio is , In other words, in the case of reverse-phase sequential connection, the pole number ratio P K / PM is always the same as that of the conventional generator as shown by the characteristic line X in Figure 5, regardless of the number of poles, and in the case of in-phase sequential connection. It changes as shown by the characteristic line Y in Figure 5, and it can be seen that the realistic pole number ratio is considerably restricted.This also shows that the reverse phase sequential connection (see Figure CM4) is in-phase in terms of machine size. The present invention is advantageous over sequential connection, and the present invention requires consideration in selecting the number of poles.Also, the machine size of the present invention can be kept at the same level or slightly larger (in phase order) than conventional power generators, making it practical. I understand.

Figure 6 shows another embodiment of the present invention! The primary winding 1"e 9a and the secondary winding lb, Q of the main engine and exciter are as shown.
The iron core for B, that is, the primary (stator) iron core 10 and the secondary (rotor) iron core 11 are shared, making it a type 02 winding induction machine 12! It is a feature. Therefore, there is an advantage that the structure of the rust conductor in a generating device with the same output can be reduced by improving the utilization efficiency of the iron core and reducing the length in the axial direction.

As explained above, according to the present invention, an excitation induction machine is provided, the output of the frequency converter is applied to its fixed primary winding, and its rotating secondary winding is connected to the rotating secondary winding of the main engine. Because it is directly connected to the motor, the rotating secondary winding of the main induction machine can be excited with alternating current at a frequency corresponding to the rotational speed of the prime mover without using slip rings or brushes.
It is possible to provide a maintenance-free and highly reliable variable speed drive constant frequency power generation device that does not require complicated maintenance and inspection around slip rings.

[Brief explanation of the drawing]

゛Figure 1 is an overall configuration diagram of a conventional variable speed drive constant frequency power generation device, FIG. 2 is an overall configuration diagram of a variable speed drive constant frequency power generation device according to an embodiment of the present invention, and FIGS. 3 and 4 is a wiring diagram showing each row of the connection state of the secondary windings of the main induction machine and excitation induction machine, Fig. 5 is a characteristic diagram showing the relationship between the pole number ratio PIIi/PM and body proportion, and Fig. 6 is a FIG. 2 is an overall configuration diagram of a variable speed drive constant frequency power generation device according to another embodiment of the present invention. 1...Main induction machine, 1a...Fixed primary winding, 1b...Rotating secondary winding, 2...Motor, 6... ... Frequency converter, 9 ... Induction machine for excitation, 9a ... Fixed primary winding, 9b ...
...Rotating secondary winding, 12...2 winding induction machine

Claims (1)

[Claims] 1. A prime mover whose speed is controlled, a wound-type main induction machine that is driven by the prime mover and generates an output at a constant frequency from its fixed primary winding, and an output at the constant frequency! a frequency converter that converts the output to a predetermined frequency corresponding to a change in the rotational speed of the prime mover, and is configured to apply the predetermined frequency output to the rotating secondary winding 1i1 of the main induction machine, the fixed primary A winding excitation induction machine having a winding and a rotating secondary winding is provided, and an output of the predetermined frequency is applied to the fixed primary winding, and the rotating secondary of the main induction machine and the excitation induction machine is Variable speed drive constant frequency generator featuring direct connection of windings 1! Device. 2. The transmission according to claim 1, characterized in that the rotating secondary windings of the main induction machine and the excitation induction machine are connected so that their phase rotation directions are opposite to each other. Drive constant frequency power generator. 3. In either the range W11 or the second term of the specific 1/Fm calculation, the main induction machine and the excitation induction machine are connected to one two-winding one-conductor unit that shares the stator core and rotor core. A variable speed drive constant frequency power generation device characterized in that it is configured as a machine.