JPS602094A - Field controller of shaft generating motor - Google Patents

Abstract

PURPOSE:To enable to operate the prescribed torque operation in a low speed range and at the constant output in a high speed range by controlling as an object to be selected higher one of the internal induced voltage and an air gap magnetic flux. CONSTITUTION:A terminal voltage V and an armature current Ia are detected, the inner induced voltage E is calculated by an inner induced voltage calculator 21, an air gap magnetic flux phi is calculated by an air gap magnetic flux calculator 22, and since the air gap magnetic flux phi is larger than the inner induced voltage E when the rotating speed of a synchronizer 3 in a high vlaue selector 23, the phi is detected, while the voltage E is reversely higher in the range that the rotating speed is high, and the E is detected. A field control thyristor 32 is controlled so that the deviation between the detected value and the set value from the magnetic flux setter 25 is set to zero.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field to which the Invention Pertains] The present invention relates to a field control device that controls field current when a shaft generator motor, which is a synchronous machine connected to a shaft, operates in a wide rotational speed range.

[Prior art and its problems]

Conventionally, when a synchronous machine is connected to a shaft and operated as a generator or an electric motor over a wide rotational speed range, the field current is controlled so that the internal induced voltage of the synchronous machine is constant. In other words, it only had the function of an automatic voltage regulator.

The internal induced voltage is E1, the rotational speed is N, the mutual inductance between the armature and the field is M, and the field '6 current is If.

If the proportionality constant is K, the relationship shown in equation (1) will be underestimated.

B=KMN If・・・・・・・・・・・・・・・・・・
・・・・・・・・・・・・(1) Operating as a generator to reduce temperature to ℃・
When the internal induced voltage E is kept constant as described above, when the rotational speed is low, that is, when N is small, the rising IT current 1f must be increased as is clear from equation (1). ,. Generally, the field current is often controlled by a thyristor, but as mentioned above, the field current If increases as the rotation speed decreases, causing problems such as going outside the range that can be controlled by the thyristor. However, increasing the capacity of the thyristor not only increases cost but also reduces the operating rate of the device.

Further, when operating as an electric motor, KE is kept constant as in the case of a generator, so constant output control is possible, but constant torque control is not possible, so there is a drawback that operation cannot be performed at a predetermined torque.

[Purpose of the invention]

In this invention, when the shaft generator-motor consisting of a synchronous machine is operated as a generator, the magnetizing current does not increase even if the rotation speed becomes low, and when it is operated as an electric motor, it can be operated with a predetermined torque in the low rotation speed region. An object of the present invention is to provide a field control device for a shaft generator motor that operates at a constant output in a high rotational speed region.

[Key points of the invention]

This invention calculates the internal induced voltage and air gap magnetic flux of a synchronous machine, and controls the field current so that the air gap magnetic flux is constant in a region where the rotation speed is low. The aim is to prevent this from happening and to enable operation at a specified torque for the Ichi 3FJ aircraft. Furthermore, in a region where the rotational speed is high, the field current is controlled so that the internal induced voltage is constant to achieve constant output operation.

[Embodiments of the invention]

FIG. 1 is a circuit diagram showing an embodiment of the present invention, in which a synchronous machine is connected to a propeller shaft of a ship.

In FIG. 1, 1 is a propeller, and a synchronous machine 3 is also connected to a propeller shaft that connects the propeller 1 and a main engine 2 of a ship for driving the propeller. This synchronous machine 3, the synchronous machine side converter 4, the system side converter 5, the DC reactor 6 inserted in the DC intermediate circuit between both converters, and the AC side of the system side converter 5 are provided. Axial power is generated with AC reactor 7 'f! This shaft generator-motor device can be connected to an inboard power system 9 via a circuit breaker 8 .

When there is surplus torque in the main engine 2, the synchronous machine 3 becomes a generator, and the generated power is generated by a constant voltage, constant frequency alternating current through the synchronous machine side converter 4, which operates as a rectifier, and the grid side converter 6, which operates as an inverter. It is converted into electric power and supplied to the load from the onboard power system 9.

When the synchronous machine 3 operates as an electric motor, an onboard generator (not shown) that is connected to the onboard power system 9 serves as a power supply source, and a system side converter 5 that operates as a rectifier using this power, The synchronous machine side converter 4, which operates as an innocoutor, converts the AC power into alternating current power, which is then supplied to the synchronous machine 3.

When the synchronous machine 3 operates as a generator or an electric motor as described above, unless the control of the field current F flowing through the synchronous machine field winding 35 is appropriate, it will not be possible to operate with the predetermined torque as described above. This may cause problems such as an abnormal increase in field current.

Means for solving these disadvantages based on the present invention will be described in detail below.

In FIG. 1, an instrument transformer 11 detects the terminal voltage of the synchronous machine 3, and this terminal voltage is converted into a DC signal by a rectifier circuit 12. Also, the armature current of synchronous machine 3 is transferred to shunt 1
3 and isolated by the isolation circuit 14. The terminal voltage output from the rectifier circuit 12 is
If the armature current output from the synchronous machine 3 is Ia, and the internal impedance of the synchronous machine 3 is Z, then the internal induced voltage E when the synchronous machine 3 is operating as a motor is expressed by equation P).

h = V −iaZ・・・・・・・・・・・・・・・
(The 2J internal induced voltage calculation circuit 21 includes a subtracter that manually calculates the terminal voltage V and armature current Ia as shown in equation (2). Note that the synchronous machine 3 is a generator. When operating as
Naturally, the polarity of Ia is also reversed.

Since the air gap Φ is obtained by integrating the above-mentioned internal induced voltage E, the air gap magnetic flux Φ is obtained by manually inputting the internal induced voltage E to the air gap magnetic flux calculation circuit 22 which is an integrator.

The internal induced voltage E and the free magnetic flux Φ obtained as described above are manually input to the high value selection circuit 23, but this high value selection circuit 23 is a selection circuit composed of diodes, and is not input manually. The internal induced voltage E and the free magnetic flux Φ
The higher signal voltage is selected as the detected value and output to the next stage. When the rotational speed of the synchronous machine 30 is low, the air gap magnetic flux Φ is larger than the internal induced voltage E, so Φ is detected, but in the region where the rotational speed is high, on the contrary, the internal induced voltage E is larger. Therefore, this E becomes the detected value.

The magnetic flux current adjustment circuit 24 is a proportional-integral Am unit,
The detected value from the above value selection circuit 23 and the magnetic flux setting device 25
A value that makes the deviation from the set value zero is output, that value is input to the firing angle regulator 26, and a firing signal corresponding to this input is given to the field control thyristor 32. The current from the field power source 31 is controlled by the field control thyristor 32, and the field current If, which is rectified by the rectifier 34 via the rotating transformer type exciter 33, flows into the synchronous machine field winding 35.

The voltage-magnetic flux characteristic diagram shown in FIG. 2 shows changes in the internal induced voltage E and the free magnetic flux Φ in the case of the above-mentioned control.

The horizontal axis in FIG. 2 is the rotational speed N of the synchronous machine 30, and the vertical axis shows the internal induced voltage E and the free magnetic flux Φ. The broken line OAB shown as a solid line in the figure shows the change in the internal d electromotive force E, and the broken line CAD shown as a one-dot chain line shows the change in the air gap Φ.

The mutual inductance between the armature of synchronous machine 3 and the field is M
, the field current is If, and if k is a proportional constant, the gap magnetic flux Φ is expressed by equation (3).

Φ= k M I (・・・・・・・・・・・・・・・
・・・・・・・・・・・・(3) On the other hand, the internal rust electromotive voltage E is (
As shown in equation (1), it increases in proportion to the rotational speed NK, so when the rotational speed N is small, the internal induced voltage E is also small, and the gap magnetic flux Φ shown in equation (3) is Since it is thick, Φ is selected, and the value of this Φ is set by the magnetic flux setting device 25.
It is controlled to the value set in . Suna-wachi world (i
11 The current If is controlled to be constant.

Since the internal induced voltage E becomes thicker than the gap magnetic flux when the rotation speed is higher than N1, this E is selected at rotation speeds higher than N1, and control is performed to keep this E constant.

As can be seen from equation (1), if E is constant and rotational speed N increases, field current I( decreases. Therefore, the free magnetic flux Φ shown by equation (3) also decreases. That is, A constant torque characteristic is obtained in a region where the rotational speed is lower than N1, and a constant output characteristic is obtained in a rotational speed of N1 or higher.

By changing the set value of the magnetic flux setting device 25, the rotational speed at which the magnitude relationship between the free magnetic flux Φ and the internal induced voltage E can be changed can be changed.

〔Effect of the invention〕

According to this invention, the higher value of the internal induced voltage and the air gap magnetic flux of the shaft power generation t#l is set as the control target, and the magnetic field current is adjusted so that the control target becomes constant. Therefore, in the low rotational speed range, there is no build-up of field current as a generator, and the motor can operate at a specified torque, and in the high rotational speed range, it operates at a constant output. It is possible to prevent an increase in the electric current capacity i.

Furthermore, the selection of the control object mentioned above is such that the cylinder (・ value) is automatically selected (・), so it can be controlled continuously regardless of the rotation speed, and rotations where the size relationship changes You can freely set the speed.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention, and FIG. 2 is a characteristic diagram showing changes in internal induced voltage and air gap magnetic flux in the present invention. 1...Propeller, 2...Main engine, 3.
...Synchronous machine, 4...Synchronous machine side converter, 5
...... Grid side converter, 9... Onboard power system, 11... Instrument transformer, 12...
Rectifier circuit, 13... shunt, 14...
Insulation circuit, 21... Internal induced voltage calculation circuit, 2
2... Air gap magnetic flux calculation circuit, 23...
High value selection circuit, 24...Magnetic flux current adjustment circuit, 2
5.Pa... Magnetic flux setting device, 26... Firing angle adjuster, 31... Field power supply, 32... Field control thyristor, 33... ...Rotating transformer type exciter, 34... Rectifier, 35... Synchronous machine excitation winding. Ia... Armature current, If... Field current, E... Internal induced voltage, ■... Terminal voltage, Φ...... Vacant magnetic flux.

Claims (1)

[Claims] A synchronous machine is connected to a shaft whose rotational speed changes, and the synchronous machine is driven by the shaft to generate variable voltage variable frequency AC power, or the variable voltage variable frequency AC power is supplied to the synchronous machine. In a shaft generator-motor capable of driving a shaft at a desired rotational speed, means for reducing the internal induced voltage of the synchronous machine, and means for reducing the free magnetic flux of the synchronous machine;
It should be noted that there is a signal selection means for selecting the above-mentioned free magnetic flux in a region where the rotational speed of the synchronous machine is low, and selecting the above-mentioned internal induced voltage in a region where the rotational speed is high, and a signal selected by the signal selection means is constant. 1. A magnetization control device for a shaft generator motor, comprising means for controlling a field current of the synchronous machine so that