JPH04150799A - Controller for rotational speed of inverter-type engine generator - Google Patents

Abstract

PURPOSE:To shorten the low-voltage duration of generation output at the time of an abrupt increase in load, thus preventing a stall, by providing means for calculating a target speed and means for causing the engine speed to increase in response to an abrupt increase in load. CONSTITUTION:When output current becomes larger and output voltage V begins to decrease from rated voltage V0, a voltage comparing means 7b actuates a speed adjuster 9 to increase fuel supply. As a result, the rotational speed of an engine 1 rises. Therefore, the operating curve (n1-n10) shifts left to right, and simultaneously the rated voltage V0 is recovered. When the output current A becomes smaller and the output voltage V begins to rise from the rated voltage V0, the voltage comparing means 7b actuates the speed adjuster 9 to decrease the fuel supply. As a result, the rotational speed of the engine 1 lowers. Therefore, the operating curve shifts right to left, and the output voltage V is back to the rated voltage instantly.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a technique for shortening the voltage drop time after a sudden load increase in a rotational speed control device for an inverter type engine generator.

(Prerequisite structure) As is well known, inverter-type engine generators are able to secure a predetermined frequency using an inverter.
This has the advantage of reducing engine operating noise and fuel consumption.

The present invention provides this inverter-type engine generator,
For example, as shown in FIG. 1 or FIG. 6, the following prerequisite structure is assumed.

That is, a generator 2 is interlocked with an engine 1, and the output voltage of the generator 2 is converted to a DC voltage by a rectifier circuit 3, then converted to an AC voltage of a predetermined frequency by an inverter 4, and then output from an output terminal 5. The rotational speed calculation means 7
An inverter-type engine generator configured to calculate the target rotational speed of the engine 1 using the rotational speed adjustment actuator 8 and adjust the rotational speed 11 m knob 9 of the engine 1 to a position corresponding to the target rotational speed. A rotation speed control device is assumed.

(Prior art) As a conventional technology having the above-mentioned premise structure,
There is one described in Publication No. 46253, which is No. 6.
It is as shown in FIGS.

In this prior art, there is no means for suppressing a drop in engine speed during a transition period in which the load suddenly increases and the engine speed temporarily rapidly drops.

In this prior art, the structure of the portion corresponding to the above-mentioned prerequisite structure is specifically as follows.

As the output detector 6, a current detector 6a is used.

As the rotational speed calculation means 7, a map type calculation means 7a is used.
is used. The map calculation means 7a has a memory therein storing data of the rotational speed indexing curve d shown in FIG. 7, and operates as follows. First, according to the rotational speed indexing curve d, the detection current IL of the current detector 6a is
From the value C, -C8°, the target rotational speed N0 of the engine 1
Determine the value of N1 to N1°. Next, the target rotational speed values N1 to N. , the deviation of the actual rotational speed detected by the rotational speed sensor 21 of the engine 1 is calculated. Then, the rotation speed adjustment tool 9 is operated by the rotation adjustment actuator 8 so that the deviation of this actual rotation speed becomes 0, and the actual rotation speed of the engine 1 is adjusted to the target rotation speed value N, ~N. . get closer to

The rotational speed indexing curve d shown in FIG. 7 is derived by following the minimum fuel consumption rate envelope curve shown in FIG. 8. This envelope curve is derived by enveloping the lowest fuel consumption points B, -13to of each output point P of the engine 1, -PIO, on each of the equal fuel efficiency curves 1-V.

(Problems to be Solved by the Invention) In the above conventional technology, which output points P, ˜P, are determined. (=load current value C3 to C8 degrees) is also excellent in that the fuel consumption rate can be minimized.

However, there is room for improvement in the following points.

(a) When the load suddenly increases, the voltage temporarily drops for a long time.

When the load increases rapidly, the rotational speed of the engine 1 rapidly decreases, the mixing performance of air and fuel decreases, and the combustion performance deteriorates.

For this reason, even if the rotational speed adjuster 9 is operated to a high-speed position corresponding to the increased load by the action of the map type calculation means 7a, there is a delay in the rotational increase of the engine l due to deterioration in combustion performance. It takes a long time for the rotation to reach the target rotation speed after the load has increased.During this time, the output of engine 1 is insufficient for the load, so the voltage supplied to the load decreases abnormally for a long time. .

(b) The engine may stall when the load increases rapidly.

If the load increases sharply, the rotational speed of the engine 1 will decrease and the combustion performance will deteriorate so much that the engine will no longer be able to maintain its rotation, and the engine may stall.

An object of the present invention is to shorten the time during which the voltage temporarily drops and to prevent engine stalling when the load increases rapidly.

(Means for Solving the Problems) In order to solve the above problems, the present invention adds the following characteristic structure to the above-mentioned premise structure, as shown in FIG. 1, FIG. 4, or FIG. 5, for example. It is characterized by

That is, a load sudden increase detection means 11 is connected to the output detector 6, and when the load detected by the output detector 6 suddenly increases, the load sudden increase detection means 11 calculates the rotation speed calculation means 7 based on this detection. The target rotational speed of the engine 1 output from the engine 1 is shifted up to a higher speed side at a predetermined ratio.

(effect) The invention works as follows.

When the load suddenly increases, the rotation speed calculation means 7 calculates a target rotation speed suitable for the load after the sudden increase, and the load sudden increase detection means 11 shifts the target rotation speed up to the high speed side at a predetermined ratio.

As a result, the rotational speed adjuster 9 is moved beyond the high-speed position corresponding to the load after the rapid increase, and is further operated to the high-speed side. As more fuel is supplied to the engine 1, the output increases, the rotation speed increases, and the time required for the engine 1 to increase to the target rotation speed after the load increases becomes shorter.

As a result, the time period for which the voltage temporarily drops after a sudden increase in load is shortened.

When the engine 1 rotates up to or near the target rotational speed, the shift up of the target rotational speed by the load sudden increase detection means 11 is canceled.

(Effects of the Invention) Since the present invention is configured and operates as described above,
It has the following effects.

(b) When the load suddenly increases, the load sudden change detection means shifts up the target rotation speed to the high speed side, and the amount of fuel supplied is increased by the amount that the rotation speed adjuster is operated to the high speed side. As a result, the speed at which the rotation of the carrot increases becomes faster (the time it takes for the rotation speed to reach the target rotation speed after a load increase becomes shorter), and the time required for the voltage to temporarily drop after a sudden load increase is shortened.

(b) When the load increases sharply, the amount of fuel supplied becomes extra as described above, increasing the engine output, thereby preventing the engine rotational speed from decreasing and preventing the engine from stalling.

(Example) Embodiments of the present invention will be described below based on the drawings.

◎Example 1 (see Figures 1 to 3) ○Assumption structure FIG. 1 shows a block circuit diagram.

In the figure, reference numeral 1 indicates a forced air-cooled gasoline engine, to which a three-phase alternating current generator 2 is interlocked and connected. The output voltage of the generator 2 is converted to DC voltage by the full-wave rectifier circuit 3, and then converted to AC voltage at a commercial frequency (50Hz or 60Hz) by the inverter 4, which can be output from the 100V single-phase output terminal 5. Configure.

Based on the detection of the electrical output of the generator 2 by the output detector 6, the target rotation speed of the engine 1 is calculated by the rotation speed calculation means 7, and the rotation speed adjustment actuator is activated via the actuator drive circuit 22. At step 8, the engine 10 rotational speed adjuster 9 is configured to be adjusted to a position corresponding to the target rotational speed.

As the output detector 6, a voltage detector 6b is used and connected to the output side circuit 23 of the inverter 4.

The rotational speed calculation means 7 includes voltage comparison means 7b.

This voltage comparing means 7b compares the detected voltage of the voltage detector 6b with the reference voltage set by the reference voltage setting means 24, and if the detected voltage is low, the rotation speed adjuster 9
is controlled to the high speed side, whereas if it is high, the control is operated to the low speed side.

The voltage comparing means 7b and the reference voltage setting means 24 each consist of a part of the functions set in the microcomputer 25.

According to this voltage comparison means 7b, the engine 1 and the generator 2
However, due to individual differences during mass production and adverse effects in high-temperature atmospheres, the output performance and power generation efficiency decrease, and even if the output performance of the engine generator becomes low, the output voltage is maintained at the rated voltage. There is an advantage.This advantage results from the following operation.

FIG. 2 shows each set rotational speed int to n of the engine 1. 2 shows the change characteristics of the output voltage V with respect to the output current A of the inverter output side circuit 23. Its characteristic curve 01~n
1° all have a downward-sloping characteristic and pass through the rated voltage V0.

When the output current A is O, the engine 1 is controlled to idle rotation.

When the output current increases and the output voltage V starts to drop from the rated voltage v0, the voltage comparison means 7b operates the rotational speed adjuster 9 to the high speed side to increase the amount of fuel supplied. Then, the rotational speed of the engine 1 increases, the characteristic curves n, -n1° are selected from the left side to the right side, and the output voltage is immediately pushed back to the rated voltage v0.

On the contrary, when the output current A becomes smaller and the output voltage V starts to rise from the rated voltage V0, the rotational speed adjuster 9 is operated to the lower speed side by the action of the voltage comparison means 7b.
Reduce fuel supply. Then, the rotational speed of the engine 1 decreases, and each of the characteristic curves n, to n,. is switched from the right side to the left side, and the output voltage V is immediately pulled back to the rated voltage.

In this way, whether the output voltage V starts to fall or rise from the rated voltage v0, the rated voltage V is ensured. Therefore, under conditions where the output performance of the engine generator is low, the decrease in the output of the engine generator can be compensated for by controlling the rotation speed adjuster 9 to a slightly higher rotation side, so that the output voltage V can be restored to the rated value. The voltage is maintained at v0 to prevent voltage shortage.

A solenoid is used as the rotational speed adjusting actuator 8 in FIG.

The rotational speed adjuster 9 consists of a speed regulating lever.

This speed control lever 9 is interlocked and connected to a throttle lever of the carburetor via a governor.

Characteristic Structure As shown in FIG. 1, a load sudden increase detection means 11 is connected to the voltage detector 6b.

The load sudden increase detection means 11 consists of a part of the functions set in the microcomputer 25, and when the load voltage detected by the voltage detector 6b suddenly increases, based on this detection, the load voltage is output from the voltage comparison means 7b. The target rotational speed of the engine 1 is configured to be shifted up to the high speed side at a predetermined ratio.

The detection signal of the load sudden increase detection means 11 is the voltage comparison means 7b.
By inputting the calculation formula of the voltage comparison means 7b,
Replace with one that shifts up to high speed.

The ratio U of upshifting to the high speed side is shown in Figure 3 (A).
・As shown in (B) or (C), the load change rate L
In the region where r is smaller than the set value Ls, it is kept at 1 times, but as it becomes larger than the set value Ls, (A)
Stepless shape as shown in the figure, (B) multi-step shape as shown in the figure, or (C)
Set it so that it rises in one step as shown in the figure.

O Modifications of Embodiment 1 In Embodiment 1 described above, it is conceivable to change a part of it as shown in the following items.

A. As the rotational speed adjusting actuator 8 in FIG. 1, an electric, hydraulic, or pneumatic servo motor, or a hydraulic or pneumatic actuating cylinder is used instead of a solenoid.

B. The rotational speed adjuster 9 is replaced by a regulating lever,
For gasoline engines, this consists of the throttle valve of the carburetor, and for diesel engines, it consists of the metering rack of the fuel injection pump.

◎Example 2 (see FIG. 4) FIG. 4 shows Example 2, which is partially modified from Example 1 shown in FIG. 1 as follows.

The voltage detector 6b is connected to the input side circuit 31 of the inverter 4. Amplifying means 32 is interposed between voltage detector 6b and voltage comparing means 7b. The detection signal of the load sudden increase detection means 11 can be input to the amplification means 32.

◎Modifications of Embodiment 2 (See FIG. 4) It is conceivable to modify a part of Embodiment 1 as described below.

C6 The voltage detector 6b is connected to the input side circuit 33 of the rectifier circuit 3 as shown by the imaginary line in FIG.

D. The amplification means 32 is relocated between the voltage comparison means 7b and the actuator drive circuit 22, as shown by the imaginary line in FIG.

◎Example 3 (see FIG. 5) FIG. 5 shows Example 3, in which a part of Example 1 shown in FIG. 1 is changed as follows.

As the output detector 6, instead of the voltage detector 6b,
A current detector 6C is used. This current detector 6C is connected to the output side circuit 23 of the inverter 4.
The input side circuit 31 or the rectifier circuit 30 may be connected to the input side circuit 33.

As the rotation speed calculation means 7, a map type calculation means 7C is used instead of the voltage comparison means 7b. This map type calculation means 7C has the same technical content as the map type calculation means 7a shown in FIG. 6, which was explained in the above (prior art) section.

The rotational speed of the crankshaft 36 of the engine 1 is detected by a rotational speed sensor 37 and fed back to the map calculation means 7C. This rotational speed sensor 37 is
It functions in the same manner as the rotational speed sensor 21 in FIG. 6, which was explained in the above (prior art) section.

[Brief explanation of the drawing]

FIG. 1 is a block circuit diagram showing Embodiment 1 of the present invention, and FIG.
The figure shows the output current/output voltage change characteristic curve of the generator 2 in Fig. 1, and Fig. 3 (A), (B), and (C) are respectively set in the rotation speed calculation means 7 in Fig. 1. FIG. 3 is a target rotational speed shift up rate curve diagram. FIG. 4 is a block circuit diagram showing Embodiment 2 of the present invention;
The figure is a block circuit diagram showing a third embodiment of the present invention. FIG. 6 is a block circuit diagram of the prior art, FIG. 7 is a curve diagram for determining the rotation speed set in the map calculation means 7a in FIG. 6, and FIG. Output curve d
FIG. 3 is a minimum fuel consumption rate envelope curve diagram used to find the minimum fuel consumption rate. DESCRIPTION OF SYMBOLS 1... Engine, 2... Generator, 3... Rectifier circuit, 4... Inverter, 5... Output terminal, 6... Output detector, 6b... Voltage detector, 6C ... Current detector, 7... Rotation speed calculation means, 7b... Voltage comparison means, 7C... Ma. - type calculation means, 8... actuator for adjusting rotational speed, 9...
Rotation speed adjuster, 11... load sudden increase detection means.゛Patent applicant Kubota Co., Ltd. No. 4 Decoy'M5 Figure

Claims (1)

[Claims] 1. A generator (2) is interlocked with the engine (1), and the output voltage of the generator (2) is converted to DC voltage by the rectifier circuit (3), and then the inverter (4) The generator (2) converts it into an alternating current voltage of a predetermined frequency and outputs it from the output terminal (5). Based on the output detector (6) detecting the electrical output of the generator (2), the rotation speed calculation means (7) and the engine (1
) and calculates the target rotation speed of the rotation speed adjustment actuator (
In the rotational speed control device for an inverter-type engine generator configured to adjust the rotational speed adjuster (9) of the engine (1) to a position corresponding to the target rotational speed in step 8), the output detector (6) A load sudden increase detection means (11) is connected to the output detector (6), and the load sudden increase detection means (11) detects a sudden increase in the load detected by the output detector (6).
Engine (1) output from rotational speed calculation means (7)
1. A rotational speed control device for an inverter-type engine generator, characterized in that the target rotational speed of an inverter-type engine generator is configured to shift up to a higher speed side at a predetermined ratio.