JPS59165996A - Operating device of induction generator - Google Patents

Abstract

PURPOSE:To prevent the adverse influence to a system by starting an induction generator by a starter of a drive engine, and gradually enhancing the exciting voltage from a low value, thereby eliminating the excess rush current at the starting time. CONSTITUTION:A switch 7 is first opened to isolate a load 5, thereby starting drive engines 2, 4. When the rotating speed of the drive engines 2 and hence an induction generator 1 rises to the vicinity of the synchronizing speed so that the detection output of a rotating speed detector 11 reaches the prescribed set value, an exciting current starts outputting from a voltage regulator 8 by a control signal of a voltage setter 9. The output voltage of the AC generator 3 and hence the exciting current supplied to the generator 1 are gradually increased in response thereto, and reaches the steady state without flowing a large rush current. Then, when the switch 7 is closed, the power can be smoothly supplied from the generator 1 to the load 5.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an operating device that prevents inrush current when starting an induction generator.

Induction generator (/i) Generates electricity by rotating a conductor root at a synchronous speed or higher; it does not require an excitation device, saves the trouble of synchronization, is easy to maintain and operate, and can be obtained at low cost. However, since it does not have an excitation device, a separate power source such as a commercial power source or a synchronous generator is required.

Normally, this separate power source is used to operate as a light guide electric machine during startup and start the drive engine, but in this case, an excessive inrush current flows and has a large impact on the power system. There was a problem in giving α6.

The present invention has focused on this point, and has been made for the purpose of providing an operation device for an induction generator that can eliminate excessive inrush current at the time of startup and prevent adverse effects on the grid.
@ A driving engine with a starter that drives the light guide electric machine, an excitation alternator that excites the induction generator, and a voltage regulator that adjusts the output voltage of the excitation alternator that is applied to the light guide electric machine. , a voltage setting device that controls a voltage regulator to gradually increase the voltage applied to the induction generator at startup from a low voltage to a working voltage.

That is, in the present invention, starting after induction power generation is performed by the starter of the driving engine (therefore, the excitation voltage is gradually increased from a low value, so that an excessive inrush current is not applied to the induction generator at the time of starting). There is no flow, which prevents any adverse effects on the excitation power supply system.

Next, an embodiment of the present invention will be described with reference to the drawings.

Figure 1 is a conceptual system diagram of the device, where (1) is an induction generator, (2) is an engine for driving the induction generator +1+, and (3) is an induction generator.
is an excitation alternator for the induction generator (1), (4) is an engine for driving the alternator (3), and (5) is a load.

The alternating current generator (3) is a relatively small-capacity synchronous generator that serves as an excitation power source for the induction power generation IfJ (1), and the output voltage is controlled by adjusting the current of the field coil (6). The output side is an induction generator fl)
is connected in parallel with the load (5) via the switch (7).
) are connected. (8) is a voltage regulator that controls the current of the field coil (6), (9) is a voltage setting device that outputs a control signal for the voltage regulator (8), (10) is a voltage transformer, (■ ) is a rotational speed detector that detects the speed of the driving engine (2). The driving engine (21 (4)) can be used with various prime movers such as a reciprocating internal combustion engine such as a diesel engine or a gas turbine. A starter 02) and a starter 3) are provided, respectively, so that the starter can be started with its own blade. , Incidentally, as the driving engine (4), a small engine with a low output is used as well as the driving engine (2). Also, each engine (
2) (4) is provided with a governor device (not shown).

The tree device has the above-mentioned configuration, and control at the time of starting is performed as follows. First, open the switch (7) and load the load (5).
) is disconnected and the drive engine (2+'[4) is started. Drive engine (2), after induction power generation (
When the rotation speed of 1) rises to around the synchronous speed) and the rotation speed detector (detection w of 1) reaches a certain set value, the control signal from the voltage setting device (9) causes the voltage regulator (8) to Excitation current begins to be output and gradually increases until it reaches a predetermined value. Correspondingly, the output voltage of the alternator (3) also increases and reaches the working voltage, which is then supplied to the induction generator (1). The excitation current also gradually increases and reaches a steady state without a large inrush current flowing, so the switch (7) must be closed.
Therefore, power can be smoothly supplied from the induction power generation a(1) to the load (5).

The pattern in which the output voltage of the AC generator (3) gradually increases may be either linear or stepwise, and the increase in output voltage starts before the induction generator (1) reaches the synchronous speed. Alternatively, it may start after the synchronous speed is reached. Further, the rate of increase in the minimum value of the output voltage is appropriately selected to a value that does not cause a large rush current to the induction generator +11. It is preferable that such control is performed after the alternator (3) reaches the synchronous speed, so the speed of the driving engine (4) is measured by a rotational speed detector (not shown). Alternatively, the detection output may be inputted to the voltage setting device (9) through an interlock.

The voltage/voltage transformer (10) detects the output voltage of the AC generator v;#, (31) and feeds it back to the voltage regulator (8) to stabilize control.

In order to carry out the above-mentioned control, it is possible to use a microcomputer as well as the voltage setting device (9). That is, a desirable relationship between the rotational speed of the induction generator (1) and the output voltage of the AC generator plate (3) is stored in advance, and the voltage regulator (8) is adjusted according to the detected output of the rotational speed detector (11).
), it is sufficient to output a control j signal that controls
A suitable actuator circuit that operates to adjust the output current in response to a control signal may be used as the voltage J base (8).

FIG. 2 is a control 70 chart when a microcomputer is used as the voltage setting device (9) in this manner. Here, the set voltage V of the voltage regulator (8) is obtained by converting the relationship V=f(t) into a numerical table and storing it in a memory as a function of time. In the figure, ■1 is the voltage regulator setting voltage at the start of startup, ■ is the voltage regulator setting voltage during steady operation, N1 is the induction generator rotation speed, and N is the rotation speed of the induction generator.

indicates the induction generator rotation speed when the voltage regulator setting voltage starts to increase.

The above embodiment is an example in which the output voltage of the alternator is adjusted by controlling the current of the field coil of the excitation alternator with a voltage regulator. For example, an induced voltage regulator of 7 tW may be connected to the output circuit of the alternator, and a VC may be used to directly change the output voltage. In addition, even if the driving engine is started by a start and the excitation power source of the working voltage is suddenly connected when the rotational speed reaches the synchronous speed, the induction generator can be used as an induction generator for starting. Although the inrush current can be reduced compared to the normal case, even in this case, an inrush current that is 3 to 4 times the steady state may flow instantaneously, which is much different from the present invention, which gradually increases the voltage of the excitation power supply. By the way, if the excitation device of the induction generator is owned by the electric power company, when the output of the induction generator becomes larger than the power consumption of the load, there will be a difference from the induction generator to the excitation nail side. There is a risk that power will be reversely supplied to a certain commercial power source, causing trouble with the power company.

Therefore, in order to prevent this trouble from occurring, it is desirable to use an output control device as shown in FIG.

In FIG. 3, (101) is a driving engine, (10
2) is an induction generator driven by a drive engine (101), (103) is a main power circuit connected to a Fi commercial power source (not shown), and (104) is a main power circuit (104).
Necessary power is supplied to the load (104) from both the main power supply circuit (103) and the induction power generation board (102).

(105) is a rotation speed detector, (106) is a speed-output converter, (107) is a voltage transformer, (108) is a current transformer, (109) is a load detector, (110) is a comparator (
111) and a speed setting device having a speed controller (112), (113) is a governor, and an induction generator (102)
The speed of is detected by a rotational speed detector (tOS),
The detection signal is converted by a speed-output converter (106) K into an output power signal corresponding to the rotational speed at that time,
Comparator (111) K input. On the other hand, the load (104
) is detected by a load detector (109) via each transformer (107) (108), and the detection signal is input to a comparator (111).

The comparator (111) is composed of, for example, a differential amplifier,
Speed-output converter (106) and load detector (109)
The input signals are compared and amplified, and an output signal corresponding to the difference between the input signals is sent to the speed controller (112).
112) Outputs the control signal for the governor (1'13) in response to the signal from the I'i comparator (111).

Here, the speed controller (112) is the induction generator (102)
When the output power of P1 and the power consumption of load (104) are W, a control signal is output such that the z'J coefficient of P = αW (α minus 1) holds, and the coefficient α is generally 0. ．．
It is set to about 8 to 0.9. As a result, the induction generator (102) is always operated at an output of 80 to 90% of the power consumption, and there is a margin for load fluctuations, so that power does not flow back into the commercial power supply during normal operation. It will disappear. Note that in the case of a load with a large fluctuation range, the coefficient α may be set to an even smaller value, and it is convenient to configure the speed controller (112) as S so that the set value can be changed arbitrarily.

As the governor (113) for controlling the speed of the driving engine (IOI) according to the control signal of the speed controller (112), for example, an electronic governor can be used.Speed controller (112) 1l-1 :Select one that is suitable for the type of governor being used. Also, the speed setting device Q
(110) can be constructed entirely using a microcomputer, and FIG. 4 shows a control flowchart when a microcomputer is used for the speed setting device (110). Here α. and α are the measured value and set value of the coefficient α, respectively, and the difference e between the two is determined, and the induction generator rotational speed Nr(e) is set so as to eliminate this difference.

Also, a rotation speed detector (105), a speed-output converter (1
The load detector (109) etc. can be selected from among various well-known configurations, and the driving engine (101) can be a reciprocating internal combustion engine such as a diesel engine or a gas turbine. Various types of prime movers can be used.

As described above, in the present invention, the induction generator is started by the starter of the driving engine, and the output voltage of the excitation AC generator is gradually increased from a low level.
This prevents excessive inrush current from flowing during startup, and prevents negative effects on the excitation power supply system.

[Brief explanation of the drawing]

Fig. 1 is a conceptual system diagram of an embodiment of the present invention, Fig. 2 is a control flow chart of the same as above, Fig. 3 is a conceptual system diagram of an example of an output control device, and Fig. 4 is a flowchart thereof. It is. 11)... @ Exclusive electric board, (2)... Drive engine, (3)... Excitation AC generator board, (8)... Voltage -
(9)... Voltage setting device, 0211... Starter. Patent Applicant Yanmar Diesel Hayashiki Company Agent Patent Attorney Department 1) Contribution Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] (1) @ A driving engine with a starter that drives the light guide electric machine, an excitation alternator that excites the induction generator, and a voltage adjustment that adjusts the output voltage of the excitation alternator that is applied to the induction generator. and a voltage setting device that controls a voltage regulator to gradually increase the voltage applied to the induction power generation t at startup from a low voltage to the working voltage by -F. Machine operating device.