JPH08196071A - Change gear - Google Patents

Abstract

PURPOSE: To obtain in economical change gear having capacity larger than that of a mechanical coupling, the convenience of electric system, and performance corresponding to that of a variable speed drive system. CONSTITUTION: The change gear comprises a first rotor 10 coupled with one rotary shaft and serves as a field electrode, and a second rotor 11 coupled with the other rotary shaft and produces a rotating field for generating torque with respect to the first rotor. The second rotor 11 has an armature winding generating a rotating field and a rotary transformer 12 for feeding AC power to the armature winding to produce the rotating field is installed to the other rotary shaft thus transmitting torque between the rotary shafts.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speed change coupling for transmitting rotational energy of a prime mover to a load having an independent rotating shaft, and more particularly to a transmission capable of transmitting rotational energy at different rotational speeds.

[0002]

2. Description of the Related Art A joint is a device for converting a mechanical rotational force into another mechanical rotational force and transmitting the mechanical rotational force. At this time, a joint accompanied by a change in rotational speed is referred to as a transmission or a speed change joint. are doing.

The simplest transmission is a gear, and the gear ratio is fixed by being defined by the gear tooth ratio. In addition, a fluid coupling is used as a variable gear ratio, and it is possible to convert from zero speed to specified speed to any speed,
Since it is possible to manufacture a large capacity joint of 4 to 5 MW class, it is used in various industries.

On the other hand, transmission devices such as eddy current joints and magnetic joints are used as electric joints for transmitting power through electromagnetic energy. Compared with mechanical and fluid type, these electric transmissions have a simple mechanism, are easy to maintain and inspect, are easy to handle, and have no mechanical coupling, so they have an insulation effect against vibration. Further, it is characterized by the fact that it has a degree of freedom with respect to a slight displacement of the rotating shaft and flexure, and also acts as an elastic joint, and is used for various purposes.

FIG. 5 shows an outline of an eddy current joint as a typical example of an electric transmission. In FIG. 5, the prime mover 1
Of the eddy current joint 3 is coupled to the rotary shaft of the eddy current joint 3, and the other rotary shaft of the eddy current joint 3 is coupled to the rotary shaft of the load 2. The eddy current joint 3 is provided with a first rotor having, on one rotary shaft, an electromagnetic coil that generates a magnetic field by a direct current supplied through a slip ring, and on the other rotary shaft, the first rotor is coupled to the magnetic field and is relatively positioned. The second rotor is provided with a torque generated by an eddy current generated by a difference in rotation speed. Then, the torque is variably controlled by controlling the direct current and the strength of the magnetic field, and the load 2 is driven at a rotation speed different from the rotation speed of the prime mover 1.

This principle utilizes the basic principle known from the Arago disk, and is well known as the principle of EC brakes and induction motors. Further, this method has a characteristic that the speed is changed in the deceleration direction and the speed cannot be increased.
Further, the difference in rotational speed between the prime mover 1 and the load 2 corresponds to a slip referred to in an induction motor, and as the torque characteristic of the induction motor shows, the transmission torque decreases as the slip increases. In addition, such an electromagnetic coupling does not have a function as a torque converter because both rotors have the same torque. This means that it is not suitable for applications that require large torque at low speeds. Also, since both torques are the same, the rotational speed difference becomes an energy difference, and there is a disadvantage that large energy is consumed as eddy current loss in low speed operation where the rotational speed difference is large, and the variable speed range is narrow. It is used in a small capacity range.

FIG. 6 shows a variable speed drive system which eliminates the above disadvantages and has a wide variable speed range and is used as a large capacity variable speed joint. In the figure, the prime mover 1 drives a generator 4, and the generator 4 converts mechanical energy into electrical energy. The power converter 6 drives the electric motor 5 at a variable speed with the electric power output from the generator 4, and the electric motor 5 drives a load. This system is an ideal transmission using a power cable as a joint, is capable of zero speed, reverse rotation, and even speedup, and has a function as a torque converter. The torque converter function is a function that converts torque so that the energy is equalized on both rotary shafts, and this enables efficient energy transfer at low speed without intermediate energy consumption. This system is used as a starter for commercial gas turbines, a starter for water turbine generators, and electric propulsion for ships.

[0008]

The mechanical coupling device such as the fluid coupling described above requires complicated handling and requires a great deal of labor for maintenance and inspection. In addition, the eddy current joint has a narrow variable speed range and is difficult to realize with a large capacity, and although the transmission system using the variable speed drive system has sufficient functional performance,
Since there are three devices, that is, the generator 4, the power conversion device 6, and the electric motor 5, the system becomes very large, and the economical efficiency becomes a problem. At present, it is difficult to realize the system over several thousand KW class.

The present invention has been made in view of the above circumstances, and an object thereof is to have a large capacity exceeding a mechanical joint, have an electric simplicity, and be equivalent to a variable speed drive system. It is to provide an economical transmission having functional performance.

[0010]

According to the invention of claim 1,
A first rotor that is coupled to one of the rotating shafts and serves as a field pole; and a second rotor that is coupled to the other rotating shaft to generate a rotating magnetic field and generate torque between the first rotor, The second rotor has an armature winding that generates the rotating magnetic field, and a rotating transformer that supplies AC power for generating the rotating magnetic field to the armature winding is provided on the other rotating shaft. , Transmitting torque between the mutual rotating shafts.

According to a second aspect of the present invention, the rotary transformer further includes a rotor winding and a stator winding, and the stator winding is excited by AC power of a variable frequency to generate a second rotating magnetic field. AC power generated in the rotor winding by the second rotating magnetic field is supplied to the armature winding of the second rotor, and torque is transmitted between the rotating shafts.

According to a third aspect of the present invention, a power converter for supplying the AC power of the variable frequency is further provided, and one of the rotating shafts is coupled with a prime mover and the other rotating shaft is coupled with a load, and the torque of the prime mover is increased. To the load.

According to a fourth aspect of the present invention, the power converter further outputs alternating-current power having a frequency corresponding to a rotation speed difference between the first rotor and the second rotor, and rotates the field pole. The relative speed between the speed and the rotational speed of the rotating magnetic field generated by the armature winding is controlled to be zero, and the rotational speed of the prime mover is transmitted to the load.

According to a fifth aspect of the present invention, the power converter further outputs AC power having a phase corresponding to a rotational position error between the first rotor and the second rotor to rotate the field pole. The relative angular difference between the position and the rotational position of the rotating magnetic field generated by the armature winding is controlled to be equal to or less than the angle at which the maximum torque is generated. As a sixth aspect of the present invention, the power conversion device further includes means for limiting the output current to a predetermined value so that the maximum torque transmitted between the rotating shafts can be arbitrarily set.

[0015]

According to the invention of claim 1, when AC power is supplied to the armature winding of the second rotor by the rotary transformer, a rotating magnetic field is generated in the second rotor, and a field pole of the first rotor is generated. Electromagnetically coupled with each other to generate torque between the first rotor and the second rotor and transmit the torque between the mutually rotating shafts.

According to a second aspect of the present invention, when the stator winding of the rotary transformer is excited by a variable frequency AC power to generate a second rotating magnetic field, the rotor winding of the rotary transformer has a variable frequency. AC power is generated, and variable frequency AC power is supplied to the armature winding of the second rotor. As a result, a variable-speed rotating magnetic field is generated in the second rotor, and torque can be transmitted between the rotating shafts having different rotating speeds.

According to the third aspect of the invention, when the variable frequency AC power is supplied from the power converter to the stator winding of the rotary transformer, the variable frequency AC power is generated in the rotor winding of the rotary transformer. A variable-frequency AC power is supplied to the armature winding of the second rotor, and a variable-speed rotating magnetic field is generated in the second rotor. As a result, torque is transmitted from one rotating shaft driven by the prime mover to the other rotating shaft having a different rotating speed, and the torque of the prime mover is transmitted to the loads having different rotating speeds.

At this time, the rotational energy difference caused by the rotational speed difference is regenerated through the armature winding of the second rotor, the rotary transformer and the power converter. According to a fourth aspect of the present invention, when the electric power converter outputs alternating-current power having a frequency controlled according to a rotational speed difference between the first rotor and the second rotor, the field pole rotates. The relative speed between the speed and the rotational speed of the rotating magnetic field generated by the armature winding becomes zero, the torque of the prime mover is transmitted to the load, and the rotational speed of the load rotates at a speed different from the rotational speed of the prime mover.

According to a fifth aspect of the present invention, when the power converter outputs AC power having a phase corresponding to a rotational position error between the first rotor and the second rotor, the field pole rotates. The relative angular difference between the position and the rotational position of the rotating magnetic field generated by the armature winding is controlled so as to be equal to or less than the angle at which the maximum torque is generated, and the rotational speed of the load is the rotational speed of the prime mover without stepping out Rotate at different speeds.

According to a sixth aspect of the present invention, when an output current limited to a predetermined value is supplied from the power converter, the maximum torque transmitted between the rotating shafts is set to a predetermined value, and the load side It is possible to limit the torque transmitted to the vehicle to a predetermined value.

[0021]

FIG. 1 shows an embodiment corresponding to claims 1 to 3 of the present invention. In FIG. 1, 1 is a prime mover on the drive side that rotates at a constant speed, such as an electric motor driven by a diesel engine or a commercial power source, 2 is a load that uses rotational energy such as a fan or a pump as a power source, and 14 is a variable voltage variable frequency. The power converter for outputting the AC power of 15 has one rotating shaft coupled to the prime mover 1 and the other rotating shaft coupled to the load 2, and is driven by the AC power of the variable voltage variable frequency supplied from the power converter 14. It is a variable speed joint device which variably controls the rotation speed of the load 2.

The variable speed coupling device 15 overhangs the field rotor (first rotor) 10 and field rotor 10 having the field pole of a permanent magnet coupled to one rotation shaft, and the other rotation. Armature rotor (second rotor) 1 connected to the shaft
1, a rotary transformer 12 coupled to the other rotary shaft, a bearing 13A supporting one rotary shaft, and a bearing 13B supporting the other rotary shaft.

The armature rotor 11 includes armature windings that generate a rotating magnetic field. Also, the rotary transformer 12 is
AC power having a variable voltage and variable frequency, which has a stator winding and a rotor winding, and is generated in the rotor winding when AC power having a variable voltage and variable frequency is supplied from the power converter 14 to the stator winding. Is supplied to the armature winding of the armature rotor 11, and AC power is supplied to the armature rotor 11 in a brushless manner.

The power converter 14 is a GTO or IGB.
By using a self-extinguishing switch device such as T, the frequency and voltage of the AC output can be freely changed and the power recovery function is provided.

As the field pole, an electromagnet may be used instead of the permanent magnet, and in this case, it goes without saying that a direct current is supplied via the slip ring. In the above structure, the prime mover 1 has two poles, the field rotor 10, the armature rotor 11, and the rotary transformer 12, and the load 2 is assumed to be a fan. The two pole AC motor 1 has a frequency of 50 Hz. 3000rpm by AC (commercial) power supply
The following describes an example in which the fan 2 is driven at a constant speed and the fan 2 is accelerated at a maximum speed of 1500 rpm from the stopped state at zero speed.

In this case, when the fan 2 is stopped, the power converter 14 first excites the rotary transformer 12 with an AC low voltage having a frequency of 50 Hz. As a result, a small AC voltage having a frequency of 50 Hz is induced in the rotor winding of the rotary transformer 12, and the armature winding of the armature rotor 11 is excited with the AC low voltage. Due to this AC excitation, the rotating magnetic field of the armature rotor 11 rotates at a constant speed of 3000 rpm, which is the same as the rotational speed of the field rotor 10, but since the strength of the magnetic field is small, the torque generated during that time is small and the fan AC motor 1 is operated in a no-load state while 2 is stopped.

Next, when the output voltage of the power converter 14 is gradually increased to gradually increase the AC excitation of the armature winding of the armature rotor 11, the field rotor 10 and the armature rotor 1
The electromagnetic coupling between 1 is gradually strengthened, torque is generated during that time, and the fan 2 starts rotating.

In this case, if the rotating magnetic field generated by the stator windings of the rotary transformer 12 is excited in the direction opposite to the rotating direction of the rotor windings, the rotary transformer rotates with the rotation of the fan 2. Since the 12 rotor windings rotate, the frequency of the AC voltage induced in the rotor windings depends on the rotation speed of the rotating magnetic field generated by the stator windings of the rotating transformer 12 and the rotor windings of the rotating transformer 12. It is determined by the rotation speed relative to the rotation speed. This relationship is obtained by using the (primary) frequency f1 of the AC voltage that excites the stator winding of the rotary transformer 12 as a parameter, and (2) the AC voltage induced in the rotor winding.
Next) The relationship between the frequency f2 and the rotation speed N is shown in the characteristic diagram of FIG.

As shown in the characteristic diagram of FIG. 3, the rotation speed N =
In the zero state, the frequency f1 of the AC voltage for exciting the stator winding of the rotary transformer 12, that is, the power converter 14
When the output frequency f1 is 50 Hz, the frequency f2 of the AC voltage induced in the rotor winding also becomes 50 Hz, no torque is generated, and the rotation speed N of the fan 2 remains zero.

Next, the output frequency f1 of the power converter 14
Is gradually decreased to gradually decrease the rotational speed of the rotating magnetic field generated by the armature winding of the armature rotor 11, an acceleration torque is generated between the field rotor 10 and the armature rotor 11. When the fan 2 is generated, the fan 2 gradually starts rotating in the same direction as the direction of rotation of the field rotor 10, and the rotating speed of the fan 2 increases by the amount that the rotating speed of the rotating magnetic field decreases.

That is, the rotating speed of the rotating magnetic field of the armature rotor 11 is always 30% of the rotating speed of the field pole of the field rotor 10.
Since the output frequency of the power converter 14 is lowered, the armature rotor 1 is controlled so as to be synchronized with 00 rpm.
The fan 2 is reduced by the decrease in the rotation speed of the rotating magnetic field of 1
Increases the rotation speed of.

For example, the frequency f2 of the AC voltage for exciting the armature winding of the armature rotor 11 is 50 Hz to 45 Hz.
When the speed is decreased to 1, the rotation speed of the rotating magnetic field of the armature rotor 11 is reduced from 3000 rpm to 2700 rpm, and the fan 2 is rotated in the same direction as the field rotor 10 by 300 rp.
Rotate at m. In this case, since the frequency f2 of the AC voltage induced in the rotor winding of the rotary transformer 12 is increased, the output frequency f1 of the power converter 14 is reduced to 40 Hz in order to reduce the frequency f2 to 45 Hz. Let

In this way, if the output frequency f1 of the power converter 14 is varied between 50 Hz and 0 Hz, the frequency f2 of the AC voltage that excites the armature winding of the armature rotor 11 is between 50 Hz and 25 Hz. Between the field rotor 10 and the rotation speed of the fan 2 in the range of 0 to 1500 rpm.
The drive can be controlled in the same direction as the rotation direction of.

Therefore, the fan 2 is driven at the maximum speed of 1500 rp.
When driven at m, the output frequency f1 of the power converter 14
Of the armature rotor 11
The armature winding is driven with an alternating voltage of frequency f2 = 25 Hz.

The joint constructed as described above functions as a reduction joint having a reduction ratio of 1/2. Further, in general, the torque characteristic of the fan, the pump, etc. is proportional to the square of the speed, and the load characteristic is proportional to the cube of the speed. Therefore, in the case of the present embodiment, the shaft torque output on the motor side is the same as the load. Since the number of revolutions is constant, the output characteristic is proportional to the square of the speed. FIG.
In this example, the load characteristic at 0 to 1500 rpm is a, and the output characteristic of the prime mover is b.

The characteristic c shown in the same figure shows the output difference between the load characteristic a and the output characteristic b of the prime mover, which corresponds to the electric power processed by the power converter 14, and the extra energy is supplied as electric power to the power source. It means to regenerate into. The magnitude of the regenerated electric power is 15% of the rated capacity at 67% of the rated speed (1500 rpm).

According to this embodiment, the size of the rotary electric machine is roughly determined by its torque.
Is approximately the same size as the electric motor 5 in the variable speed drive system of FIG. 6, the capacity of the power conversion device 14 may be 15% of the rated capacity of the variable speed coupling device 15, and the generator 4 is unnecessary. Then, from zero speed to the maximum speed, efficient power transmission becomes possible without the energy loss of the eddy current joint. That is, since the power conversion device in the conventional variable speed drive system passes all the energy to be converted, the device capacity required the maximum capacity of the load, but according to the present embodiment, the maximum capacity of the load is 1
It may be about 5%, and unlike the conventional eddy current joint, all the energy due to the speed difference between the driving side and the load side is not consumed as a loss, and efficient operation becomes possible.

Further, the capacity of the power converter 14 may process the power of the output difference between the drive shaft side and the load shaft side. That is,
If the output on the drive side is P1, the rotation speed is n1, the output on the load side is P2, the rotation speed is n2, and the transfer torque is τ, the transfer torque τ is the same on the drive side and the load side.
= Τ · n1 and P2 = τ · n2.

Therefore, in the power conversion device 14, the output difference Δ
The energy of P = P1 -P2 is processed, but since the transmission torque is set so that τ is proportional to the square of the rotational speed n2 on the load side and the output on the drive side and the output on the load side match at the rated speed, When the ratio n2 / n1 = 2/3, ΔP becomes maximum,
Pmax = 0.15 · τmax · n2max. That is, the maximum output difference is 67% of the rated speed, and the amount is 15% of the rated capacity.

An embodiment corresponding to claims 1 to 6 of the present invention is shown in FIG. In FIG. 2, 16A and 16B are the prime mover 1.
And a speed (position) detector for detecting the rotation speeds (positions) ω1 and ω2 of the load 2, respectively, and 17 is a setter for setting the maximum value for limiting the maximum value of the output voltage of the power conversion device 14, Is a coefficient unit, and 19 is a subtractor.

The subtractor 19 is a velocity (position) detector 16A.
From the rotational speed ω1 of the prime mover 1 detected via the, the value obtained by doubling the rotational speed ω2 of the load 2 detected via the speed (position) detector 16B by the coefficient unit 18 is subtracted, and the difference value ωa Is output as a frequency reference. The power converter 14 supplies the variable speed coupling device 15 with AC power having a frequency corresponding to the frequency reference ωa. In this case, the AC power is supplied so that the rotating direction of the rotating magnetic field generated by the stator winding of the rotary transformer 12 is opposite to the rotating direction of the rotor winding.

In the above structure, when the operation is started, the load 2 is stopped first, so that the AC power having the same frequency as the rotation speed ω1 of the prime mover 1 is supplied from the power converter 14 to the variable speed coupling device 15. . In this case, the power converter 14 outputs AC power having a phase corresponding to the rotational position error between the field rotor 10 and the armature rotor 11, and the field rotor 1
The relative angular difference between the rotational position of 0 and the rotational position of the rotating magnetic field generated by the armature rotor 11 is controlled to be equal to or less than the angle at which the maximum torque is generated, and the torque is transmitted from the prime mover 1 side to the load 2 side. The load 2 starts rotating.

When the load 2 starts rotating, the power converter 1
4 is the rotation speed ω 1 of the prime mover 1 to the rotation speed ω of the load 2.
The AC power of the frequency ωa, which is the value obtained by doubling 2 is output, and the relative speed between the rotation speed of the field rotor 10 and the rotation speed of the rotating magnetic field generated by the armature rotor 11 is zero. The engine speed is controlled so that the rotational speed of the prime mover is transmitted to the load.

As a result, the rotation speed ω2 of the load 2 increases and the output frequency ωa of the power converter 14 decreases. The rotational speed ω2 of the load 2 is the rotational speed ω1 of the prime mover 1.
When the frequency reference ωa becomes zero, the power converter 14 outputs DC power without reversing the phase rotation, and the stator winding of the rotary transformer 12 is DC-excited to rotate the rotary transformer. AC power having a frequency equal to the rotation speed ω 2 of the load 2 is supplied from the 12 rotor windings to the armature rotor 11
Is supplied to. As a result, the rotation speed of the rotating magnetic field generated by the armature rotor 11 becomes equal to the rotation speed ω 2 of the load 2, and the rotation speed of the field rotor 10 and the armature rotor 1
The relative speed to the rotation speed of the rotating magnetic field generated by 1 is controlled to be zero.

These controls are controlled by a speed (rotational position) control system consisting of a PI controller provided inside the power converter 14 with ω1 as a speed (rotational position) reference and ω2 as a speed (rotational position) feedback. It

In this way, the rotation speed of the field rotor 10 and the rotation speed of the rotating magnetic field generated by the armature rotor 11 can be completely synchronized, and the rotation speed ω of the load 2 can be made.
2 can be controlled to 1/2 of the rotation speed ω 1 of the prime mover 1 in a self-controlled manner.

The maximum value of the transmission torque is set by the setter 17
It can be determined by limiting the maximum output voltage of the power converter 14 with the setting value of. In the above description, an example using the speed detection signal is shown, but since the angle of the rotor is controlled by self-control similarly to the vector control of the synchronous motor, a structure using a position detection signal such as a synchro resolver should be adopted. You can

Further, in FIG. 1, the variable speed coupling device 15 has been described as a general synchronous motor structure for the sake of simplicity.
The field rotor 10 and the armature rotor 11 can be similarly implemented by using a synchronous motor having a structure in which two rotating disks face each other.

[0049]

According to the present invention, the capacity is larger than that of mechanical joints such as fluid joints, the electric joint is simple, and
It is possible to provide an economical transmission that has a functional performance equivalent to that of a variable speed drive system and that is compact.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment corresponding to claims 1 to 3 of the present invention.

FIG. 2 is a configuration diagram of an embodiment corresponding to claims 1 to 6 of the present invention.

FIG. 3 is a characteristic diagram for explaining the operation of the rotary transformer 12 used in the variable speed joint device 15 of FIGS. 1 and 2.

FIG. 4 is a characteristic diagram of the outputs of the prime mover 1 and the load 2 and the electric power processed by the power conversion device 14 in the above embodiment.

FIG. 5 is a configuration diagram of a conventional eddy current joint.

FIG. 6 is a configuration diagram of a variable speed joint according to a conventional variable speed drive system.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Motor 2 ... Load 10 ... Field rotor (1st rotor) 11 ... Armature rotor (2nd rotor) 12 ... Rotating transformer 13 ... Bearing 14 ... Electric power converter 15 ... Variable speed joint device 16 ... Speed detector 17 ... Voltage setting device 18 ... Coefficient device 19 ... Subtractor

Claims (6)

[Claims] 1. A first magnetic pole which is coupled to one of the rotating shafts to form a field pole.
A rotor and a second rotor that is coupled to the other rotating shaft and that generates a rotating magnetic field to generate a torque between the first rotor and the second rotor are provided, and the rotating magnetic field is generated in the second rotor. A rotary transformer that has an armature winding and supplies AC power for generating the rotating magnetic field to the armature winding is provided on the other rotating shaft, and torque is transmitted between the rotating shafts. Characteristic transmission. 2. The transmission according to claim 1, wherein the rotary transformer includes a rotor winding and a stator winding, and the stator winding is excited by an alternating-current power having a variable frequency to generate a second electric current. Generating a rotating magnetic field of the second rotating magnetic field and supplying AC power generated in the rotor winding by the second rotating magnetic field to the armature winding of the second rotor so that torque is transmitted between the rotating shafts. Transmission characterized by. 3. The transmission according to claim 2, further comprising a power conversion device that supplies the variable frequency AC power.
A transmission characterized in that one of the rotating shafts is connected to a prime mover, the other rotating shaft is connected to a load, and the torque of the prime mover is transmitted to the load. 4. The transmission according to claim 3, wherein the power converter outputs AC power having a frequency according to a rotation speed difference between the first rotor and the second rotor, The relative speed between the rotation speed of the magnetic pole and the rotation speed of the rotating magnetic field generated by the armature winding is controlled to be zero,
A transmission which transmits the rotation speed of a prime mover to a load. 5. The transmission according to claim 4, wherein the power converter outputs AC power having a phase corresponding to a rotational position error between the first rotor and the second rotor, A transmission, wherein a relative angular difference between a rotational position of a magnetic pole and a rotational position of a rotating magnetic field generated by the armature winding is controlled to be equal to or less than an angle at which maximum torque is generated. 6. The transmission according to claim 5, wherein the power converter includes means for limiting the output current to a predetermined value so that the maximum torque transmitted between the rotating shafts can be arbitrarily set. Transmission characterized by.