JPH0221216B2 - - Google Patents

Description

[Detailed Description of the Invention] A device for transmitting power from a prime mover to a load by mechanically and electrically coupling a rotating electrical machine having an electromagnetic coupling and a stator has already been disclosed in Patent Application Publication No. 62 in 1982.
No. 53-35848.
These devices do not use mechanical gearing;
Since it is possible to create a power transmission reduction mechanism, it is highly reliable and seems suitable for a power transmission device that drives a load by decelerating a diesel engine with large torque fluctuations. However, such conventional power transmission devices also have major drawbacks. The disadvantage is that when the rotational speed of the load is low, the dimensions of the rotating electric machine connected to the electromagnetic coupling become very large, which not only makes the device uneconomical, but also reduces its efficiency. Especially when the rotating electric machine is an induction motor, the rotation speed on the load side is particularly low.
If the speed is 50 rpm, it is impossible or difficult to manufacture a large-capacity induction motor, such as 5000 KW, and the efficiency is extremely low.

Let's take ship propulsion as an example. In order to save energy, the main power of marine propulsion engines has become diesel engines, but diesel engines have a speed of about 400 rpm.
Cycle engines and 100rpm two-cycle engines are the two types of current large-capacity diesel engines. The propeller rotation speed of ships driven by such diesel engines has been increased from about 100 rpm in the past in order to increase the ship's propulsion efficiency.
The recent trend is to lower the speed to about 50 rpm. In such a case, the above-mentioned patent application publication No. 62 of 1978
The conventional electromagnetic power transmission device disclosed in Japanese Patent Application No. 53-35848 has the above-mentioned disadvantages. In the case of this conventionally known patent application No. 1983-35848, as mentioned above, there is a disadvantage that the size of the rotating electric machine having the stator electrically and mechanically coupled to the electromagnetic coupling becomes large. Since the axial length of a rotating electric machine with a stator is long, when a stator type rotating electric machine is inserted between the electromagnetic joint and the load as shown in the arrangement shown in Patent Application Publication No. 53-35848. , the length of the entire power transmission device between the prime mover and the load becomes longer. This also results in inconveniences in layout, such as having to lengthen the engine room of the ship.

On the other hand, if a sudden load change occurs, as in Patent Application Publication No. 53-35848, there is a possibility that disturbances may occur. In other words, if we consider the case where the rotating electric machine with a stator is a synchronous motor, at a constant load, the synchronous motor operates with both the load angle δ ₁ and the electromagnetic coupling load angle δ ₂ constant. When the load changes, both the load angle δ ₁ of the synchronous motor and the load angle δ ₂ of the electromagnetic joint change. If the load suddenly increases,
The load angle δ ₁ of the synchronous motor increases, but the increase in the load angle δ ₁ of the synchronous motor does not increase by itself, but results in an increase in the load angle δ ₂ of the electromagnetic joint. The load angle δ ₂ of the electromagnetic joint in this case is the load angle δ ₂ when the electromagnetic joint is considered as a synchronous motor.
In other words, the phase difference between the no-load induced electromotive force and the terminal voltage when an electromagnetic coupling is considered to be a synchronous motor whose rotation speed is the speed difference between the rotation speed of the prime mover side and the rotation speed of the rotor on the load side. is considered to be the load angle.

Now consider the case where the load on the electromagnetic joint connected to the synchronous motor suddenly becomes overloaded. In that case, when the load angle of the synchronous motor increases from δ ₁ , the load angle δ ₂ of the electromagnetic joint as a synchronous motor also increases as shown in FIG. When the load suddenly becomes overloaded in this way, the load angle of the electromagnetic coupling as a synchronous motor and synchronous generator tries to increase, but it does not immediately settle to the new load angle corresponding to the new load, and the inertia of the rotating body increases. Therefore, the load angle is periodically varied around that point. Such a disturbance phenomenon occurs, resulting in an unstable operating state. When the disturbance becomes severe and the variation range of the load angle becomes large, the synchronous motor finally loses synchronization with the power supply and stops, and the electromagnetic coupling as a synchronous generator also stops due to the loss of synchronization. It becomes like this.
In FIG. 3, the limit range of such a variation range of the load angle is represented by δ ₃ , and it is shown that when the load angle exceeds this range, the above-mentioned escape state occurs.

The object of the present invention is to provide a power transmission device based on electrical and mechanical coupling of a rotating electric machine having an electromagnetic coupling and a stator, which is based on the above-mentioned known patent application publication.
No. 62 of 2013 and Patent Application Publication No. 53-35848, it is possible to reduce the size and weight of a rotating electric machine having a stator, shorten the longitudinal dimension of its power transmission device, and thereby improve the alignment. In addition to shortening the
On the other hand, the purpose is to prevent the system from going out of control when the load suddenly changes, and to improve the transient stability of the power transmission device.

In order to achieve the above objectives, the present invention has two rotors 1 that rotate relatively and face each other, as shown in the specific connection diagram example in FIG. 1 and the partial configuration diagram example in FIG. 2. 2, the load-side rotor 1 of an electromagnetic coupling 18 having an armature winding 22 on at least one of the rotors 1 and the large gear 9 are coupled, and the rotor of a rotating electric machine 7 having a stator on the other hand Combined small gear 1
0 is meshed with the large gear 9 to form a reduction gear device 8.
is arranged so that deceleration power can be transmitted from the output shaft 17 of the rotor of the rotary electric machine 7 having the stator to the load 6 via the reduction gear device 8, while the load side rotation of the electromagnetic coupling 18 is In order to directly drive the load 6 by the child 1, the load side rotor 1 of the electromagnetic coupling 18 and the load 6 are mechanically coupled, and
The other rotor 2 of this electromagnetic coupling 18 is arranged so as to be rotationally driven by the prime mover 5, and electrical connection is made between the rotating electrical machine 7 having the stator and the armature winding of the electromagnetic coupling 18. Therefore, the rotating electric machine 7 having the stator is arranged so as to receive electric power from the electric output terminal of the electromagnetic coupling 18, and one side directly receives the mechanical power from the output shaft 11 of the prime mover 5 through the electromagnetic coupling 18. The other drives the load 6 as the electric output of the electromagnetic coupling 18 to the rotary electric machine 7 having a stator, and then transmits the converted mechanical output to the load 6 via the reduction gear device 8. The brake winding 21 is arranged on the pole surface of the field pole 23 of the rotor 2 of the electromagnetic coupling 18, and the brake winding 21 is arranged like the rotor winding of a cage induction machine.
It is characterized by shorting between the two.

In the case of the electromagnetic coupling 18 described above, the armature winding 22 is provided on the rotor 1 among the rotors 1 and 2, and the slip ring 3 is provided to connect the armature winding 22 with external equipment. The electrical connection with the armature winding of the electric machine 7 is made by electric wires 14. Rotor 1
This refers to a rotor that is connected to the load 6 by the shaft 12, and also when the armature winding is provided on the rotor 2 that connects the prime mover 5 to the output shaft 11. Conceivable. The gear system 8 is connected to the rotor 1 of the electromagnetic coupling 18 , which is connected to the load 6 . In the case of FIG. 1, the gear device 8 is a one-stage type consisting of a pinion 10 and a large gear 9, and the gear device 8 has a one-stage reduction when viewed from the output shaft 17 of the rotating electrical machine 7 toward the load 6. In the figure, electromagnetic joint 18
A field winding 20 is provided to which DC excitation current is supplied to the rotor 2, and a slip ring 4 is provided as a terminal for external connection of the field winding 20, and during steady operation, the armature winding 22 is connected to the slip ring 3. ,
Excitation current is supplied to the slip ring 4 via an AC electrical connection wire 15, a rectifier 13, and a DC electrical connection wire 16. However, it is not necessarily necessary to supply the excitation current for the field winding in such a self-excited manner;
It can also be supplied from other DC power sources. Particularly during startup, such a separately excited system may be used. The rotating electric machine 7 may be a synchronous motor or a cage induction motor. If the rotation speed of the load 6 is 50 rpm and the reduction ratio of the gear device 8 is 8, then the rotation speed of the rotating electric machine 7 can be set to 400 rpm.
Compared to the case of 50 rpm, it is much easier to manufacture and also cheaper. It also improves efficiency.
For example, if the rated efficiency of a cage induction motor with a 5000KW output and a rotation speed of 50rpm is 90%,
If the efficiency of 5000KW and 400rpm can be made 94%, and the efficiency of the gear device is 99.2%, the overall efficiency will be about 93%, which clearly means that an improvement of about 3% can be expected. If this gear device is a two-stage combination and a reduction ratio of, for example, 36:1 is obtained, the rotational speed of the rotating electric machine 7 is set to 1800 rpm, the size of the rotating electric machine 7 is made more compact, and the efficiency is further increased. I can do it. In that case, it is easy to make the efficiency of the rotating electric machine 7 98%, and if the efficiency of the gear device is 98.5%, the overall efficiency is 96%. It is also possible to use a wound induction motor as the rotating electrical machine 7 and connect a frequency converter to its primary or secondary circuit. Electrical connection line 14 in Figure 1
A forward/reverse phase conversion switchgear is provided in the circuit, and the phase connections can be arranged in either the forward direction or the reverse direction. Thereby, the rotation direction of the prime mover 5 and the rotation direction of the load 6 can be made to be the same direction or to be made to be in opposite directions.

It is also possible to use a DC machine as the rotating electric machine 7 and electrically connect its armature winding to the armature winding of the electromagnetic joint 18 via a rectifier. The rotating electrical machine 7 can also be a commutatorless motor.

The operation of the present invention will be explained. When one rotor 2 of the electromagnetic coupling 18 is driven by the prime mover 5 at a rotational speed n ₀ rpm, the other rotor 1 rotates n ₂ rpm cm ² ,
Due to the speed difference n ₁ of n ₀ -n ₂ , the electromagnetic coupling 18 outputs the generated power to the outside of the slip ring 3, and the rotating electrical machine 7 receives the power. In FIG. 1, current flows through the armature winding 22 of the rotor 1, and an electromagnetic coupling effect is established between it and the field pole 23 of the rotor 2, and the motor 5
The shaft 12 passes directly to the load 6 for n ₂ minutes out of the rotational speed n ₀ , and torque is transmitted from the load side rotor 1 of the electromagnetic coupling 18, and for n ₁ minute, the torque is transmitted from the electromagnetic coupling 18 to the rotating electrical machine 7. Power is supplied to the

Now, if the rotating electric machine 7 is a synchronous motor,
The following relationship holds true.

n ₁ = n ₀ − n ₂ (1) 120f = p ₁ n ₁ (2) n ₂ = n ₃ /r (3) n ₃ p ₂ = 120f (4) The frequency of the AC power, p ₁ and p ₂ are the numbers of poles of the electromagnetic coupling 18 and the rotating electrical machine 7, respectively, n ₃ is the rotational speed of the rotating electrical machine 7, and r is the reduction ratio of the gear 8.

Substituting equation (3) into equation (4) and comparing it with equation (2), we get n ₂ ×
r x p ₂ = p ₁ n ₁ , n ₁ = n ₂ x r x p ₂ / p ₁ (5) From equations (1) and (5), n ₀ = n ₂ (r x p ₂ / p ₁ +1) (6) When the electromagnetic coupling 18 and both armature windings of the rotating electrical machine 7 are connected in reverse phase order using the electrical connection wire 14, the rotation direction of the prime mover 5 and the rotation direction of the load 6 become opposite to each other, and ( Equation 1) becomes n ₁ = n ₀ + n ₂ , and equation (6) becomes n ₀
= n ₂ (r×p ₂ /p ₁ −1).

Now, in Figure 1, the rotation speed of prime mover 5 is 100 rpm,
Assuming that the rotational speed of the load 6 is 50 rpm, the equation (6) above holds true if r=8, p ₁ =32, and p ₂ =4.
That is, when power is transmitted from the low-speed prime mover 5 to the low-speed load 6, only the electromagnetic coupling 18 is made into a multi-pole machine, and the rotating electric machine 7 can be easily manufactured as a small-pole machine, resulting in an inexpensive and highly efficient machine.

In this case, the important thing is that when power is transmitted from a prime mover 5 such as a diesel engine to a load propeller 6, providing a mechanical gear device in the power transmission mechanism is reliable because it receives torque fluctuations on the tooth surface. It is generally considered to be sexually undesirable. However, in the present invention, since the gear device 8 is connected to the load side of the electromagnetic coupling 18, the output shaft 11 of the prime mover 5
Torque fluctuations in are sufficiently absorbed by the electromagnetic coupling 18 and are not transmitted to the gear device 8. In other words, the electromagnetic coupling 18 not only has a speed reduction mechanism, but also serves as a protection device for the gear device 8. The capacity of this gear device 8 corresponds to that of the rotating electric machine 7, and may be n ₁ /n ₀ of the capacity of the prime mover 5. For example, when transmitting power from a prime mover output of 10,000 kW,
The rotation speed of the prime mover output shaft 11 is 100 rpm, and the load is 6.
If the rotation speed of is 50 rpm, the capacity of the gear device 8 may be 5,000 KW.

One rotor 2 in the electromagnetic coupling 18 in FIG.
is a field rotor around which a field winding 20 is wound, and the field poles 23 are coupled at a coupling portion 19. This field pole 2
The damper winding 21 provided on the pole surface of the damper 3 short-circuits the damper windings like the rotor winding of a cage induction machine. When torque fluctuations occur on the output shaft 11 of the prime mover 5, such fluctuations are prevented from being transmitted to the load side, that is, the gear device 8, due to the gap in the electromagnetic coupling.
In other words, the amplitude of the transmitted torque fluctuation is attenuated.

As mentioned above, the present invention has been disclosed as a publicly known patent application published in 1983-35848.
There are the following basic differences in structure compared to the No. That is, a gear device that meshes with small gears and large gears is coupled between the output shaft of the rotating electrical machine having the a stator and the load-side rotor of the electromagnetic coupling. b A damper winding is provided at the field pole of the electromagnetic joint. Owing to these structural features, the present invention has the following operating and effect features that are different from those of the known patent application published in Japanese Patent Application Publication No. 53-35848.

(1) By providing the gear device 8, the above formula (6) can be
If you want to set the value of n ₀ /n ₂ = r×p ₂ /p ₁ +1 to 8, if you change the number of poles p ₂ of the rotating electrical machine 7 and the number of poles p ₁ of the electromagnetic coupling 18 to 28 poles and 4 poles, respectively. , r=1
becomes. If this is set to r=7, both p ₂ and P ₁ become four poles. r=1 is the case where the gear device 8 is not provided, and r=7 is the reduction ratio of the gear device.
Comparing the two, in the case of Patent Application Publication No. 1983-35848 without a gear device 8, the number of poles of the rotating electrical machine 7 is 28 poles, whereas in the case of the present invention, the number of poles of the rotating electrical machine 7 is 4 poles. That's a good thing. In equations (1) and (2), n ₁ = 420 rpm, n ₀ = 480 rpm, n ₂ = 60 rpm
and p ₁ = 4, then f = 4 x 420/120 = 14
Hz, so if p ₂ = 4 in equation (4), n ₃ =
420rpm, and when p ₂ = 28, n ₃ = 60rpm. Therefore, if both have the same capacity and are, for example, 10000KW,
The ratings with and without the gear device 8 are as follows. i.e. 10000KW, 14
Hz, 420rpm, 4 poles, 10000KW, 14Hz,
60rpm, 28 poles. Under the same output and frequency, one side is 420rpm, 4 poles, and the other side is 420rpm.
Since it has 60 rpm and 28 poles, when comparing the torque that can be produced, the former is only 1/7 of the torque of the latter.
It is well known that the size and weight of a rotating electrical machine is determined by the torque it can produce. Therefore, it can be seen that when the gear device 8 is provided as in the present invention, the dimensions and weight of the rotating electric machine having the stator are smaller and lighter than when the gear device 8 is not provided. Considering the arrangement, the patent application publication date
In No. 53-35848, there is a stator-type rotating electrical machine between the rotor of the electromagnetic coupling and the load, and since its size is large, the rotating electrical machine with the stator is connected from the prime mover through the electromagnetic coupling. The so-called length or axial dimension of the load must be very large. In the present invention, a gear device 8 is interposed in place of such a large-sized rotating electric machine, and it is clearly smaller in size than the rotating electric machine in the above-mentioned patent application publication No. 53-35848, and is capable of transmitting power. The axial dimensions of the device are greatly saved and significant operational advantages are obtained which result in very advantageous arrangement results. This can be said to be an extremely important feature when considering the arrangement in the engine room of a ship.

(2) Due to the structural feature of providing a damper winding at the field pole of the electromagnetic joint, the present invention provides the following advantages. When the load on the electromagnetic joint as a synchronous motor changes, its load angle δ changes. For example, as shown in Fig. 3, when the electromagnetic coupling is operating at a load angle δ ₂ with an output below the rated output as a synchronous motor, and the load gradually increases, the new load angle δ ₄ changes. Calm down. However, when the load increases dramatically, it is not possible to immediately shift to δ ₄ due to the inertia of the rotor. Therefore, the torque generated by the rotating electrical machine 7 and the load-side rotor 1 of the electromagnetic coupling 18 is insufficient for the new load, and the rotor decelerates from the perspective of the motor, increasing its load angle. At the same time, since the power generated by the electromagnetic coupling as a generator is insufficient, the electromagnetic coupling 1
The motor side rotor 2 of No. 8 is also decelerated from that point of view, and the load angle δ of the electromagnetic coupling 18 as a generator gradually increases. In FIG. 3, the horizontal axis shows time t, and the vertical axis shows load angle δ.

The load angle δ of the electromagnetic coupling 18 as a generator and the rotational speed difference between the two rotors 1 and 2 of the electromagnetic coupling 18, i.e.
The relationship between n ₁ =n ₀ −n ₂ in equation (1) is dδ/dt=n ₁₀ −n ₁ . In this case, n ₁₀ is the synchronous rotational speed of the rotational speed difference between both rotors 1 and 2, and n ₁ is its instantaneous value. Along the curve A in FIG. 3, δ changes from δ ₂ , and due to the deceleration of the prime mover side rotor 2, the rotational speed difference n ₁ decreases, and δ gradually increases, but δ ₄
When dδ/dt reaches the maximum, that is, the rotation speed difference n ₁ has become the minimum, so it cannot settle down to δ ₄ , and δ continues to increase due to inertia. When δ ₄ or more, the output generated by the electromagnetic coupling 18 as a generator becomes larger than the load output, so the rotational speed difference n ₁ between the rotors increases, the prime mover side rotor 2 is accelerated, and δ ₂ The kinetic energy released _by rotor ₂ is absorbed again until it reaches δ ₄ from
When dδ/dt=0, the load angle δ ₅ is reached and the generated output is much larger than the load output. Therefore, rotor 2 reaches the synchronous speed or higher, and when it passes through δ ₄ again, the rotational speed of rotor 2 reaches its maximum, and dδ/dt=n ₁₀ −n ₁ takes a large negative value, and the initial load It will return to near the angle δ ₂ . In this way, δ periodically fluctuates back and forth around δ ₄ , and it takes some time for the amplitude to gradually attenuate and settle to δ ₄ due to electrical and mechanical losses. As a result rotor 2
will repeat oscillations of acceleration and deceleration. However, although it is good when such a final calm is obtained, there is a phenomenon in which this fluctuation is exacerbated and violent vibrations occur. This is called disorder, and if the disorder becomes severe, it may cause a loss of synchronization. . In FIG. 3, the curve B shows the stability limit curve, and δ at that time is δ _3. If the curve C exceeds this value, it is unstable and will be out of synchronization. If disturbance occurs, the rotor 2 equipped with field windings will oscillate back and forth in response to the rotating magnetic field created by the armature current, and eddy currents will flow to the magnetic pole faces and work to dampen this vibration. However, in order to further enhance this effect, a brake winding is provided on the magnetic pole piece, as in the present invention. This winding has no effect when δ is constant, but when δ fluctuates, current flows by cutting off the rotating magnetic flux, creating a braking torque between the rotating magnetic flux and keeping δ constant. It acts on This can improve stability.

[Brief explanation of drawings]

FIG. 1 is a specific electrical connection diagram of the present invention,
FIG. 2 is a partial connection diagram thereof. FIG. 3 is an operational diagram of the apparatus of the present invention. The following symbols represent the main parts of the figure below. 1: One rotor of the electromagnetic coupling, 2: The other rotor of the electromagnetic coupling, 3: Slip ring, 4: Slip ring, 5: Prime mover, 6: Load, 7: Rotating electric machine, 8: Gear device, 9 : Large gear, 10: Pinion, 11: Output shaft of prime mover 5, 12: Electromagnetic coupling 1
8 output shaft, 13: rectifier, 14: electrical connection wire, 15: AC side connection wire of rectifier, 16: DC connection wire of rectifier, 17: output shaft of rotating electrical machine, 18: electromagnetic coupling, 19 : Field pole coupling part,
20: Field winding, 21: Brake winding, 22: Armature winding of electromagnetic joint, 23: Field pole.

Claims (1)

[Claims] 1. An electromagnetic coupling that has two rotors that rotate relative to each other and that face each other, at least one of the rotors has an armature winding, and the load side rotor and large gear are coupled, and one of the rotors has a stator. A small gear connected to the rotor of the rotating electrical machine is meshed with the large gear to create a reduction gear device, thereby reducing the speed from the output shaft of the rotor of the rotating electrical machine having the stator to the load via the reduction gear device. Arranged to transmit power,
On the other hand, in order to directly drive the load with the load-side rotor of the electromagnetic coupling, the load-side rotor of the electromagnetic coupling and the load are mechanically coupled, and the other rotor of the electromagnetic coupling is rotationally driven by the prime mover. By electrically connecting the rotating electric machine with the stator and the armature winding of the electromagnetic joint, the rotating electric machine with the stator receives power from the electrical output terminal of the electromagnetic joint. The output from the output shaft of the prime mover passes through the electromagnetic coupling, and one directly drives the load as mechanical force, while the other uses the electromagnetic coupling's electrical output to drive a rotating electrical machine with a stator. Then, the converted mechanical output is arranged so as to transmit power to the load via the reduction gear device, and a brake winding is provided on the pole surface of the field pole of the rotor of the electromagnetic joint, and the rotation of the cage induction machine is A prime mover drive power transmission device characterized by short-circuiting braking windings like child windings.