JP2700836B2 - Inverter type engine generator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION << Field of Industrial Application >> The present invention relates to an inverter-type engine generator.

<< Premise structure >> As is well known, an inverter-type engine generator can maintain its output voltage at a predetermined frequency by an inverter, so that the rotation speed of the generator can be changed freely and when the power load is low. In addition, there is an advantage that the engine operating speed can be set low to reduce the engine operation noise and the fuel consumption rate can be reduced.

The prerequisite structure of the inverter-type engine generator to which the present invention is directed is, for example, as shown in FIG. 1, FIG. 2 or FIG.

The generator 2 is connected to the engine 1 in an interlocked manner, and the output voltage of the generator 2 is converted into a DC voltage by the rectifier circuit 4, then converted into an AC voltage of a predetermined frequency by the inverter 5, and output from the output terminal 6. The rotation speed calculating means 8 calculates the target rotation speed of the engine 1 based on the detection of the electrical output of the generator 2 by the output detection means 7, and the rotation speed adjusting actuator 9
The rotation speed adjusting means 10 is configured to be adjusted to a position corresponding to the target rotation speed.

<< Conventional Technology >> In the above-mentioned premise structure, the structure of the part for automatically controlling the rotation speed of the engine is described in Japanese Patent Publication No. 63-46 in the prior art.
No. 253 is disclosed, and is configured as shown in FIGS. 4 to 6. FIG.

The output detecting means 7 comprises a current detector 7x. The current detector 7x is connected to the circuit 11 on the output side of the inverter 5, and is configured to detect the current on the output side of the inverter 5.

The rotation speed calculating means 8 comprises a map type control circuit 8x. The map-type control circuit 8x has a memory in which data of the rotation speed index curve d shown in FIG. 5 is stored. First, based on the rotation speed index curve d, the detected current of the current detector 7x is determined. From the value of IL, the value of the target rotation speed N of the engine 1 is calculated, and the deviation of the actual rotation speed detected by the rotation speed sensor 51 of the engine 1 from the value of the target rotation speed N is calculated. The rotation speed adjusting means 9 is operated by the rotation speed adjusting actuator 9 so that the actual rotation speed of the engine 1 becomes close to the value of the target rotation speed N.

The rotation speed index curve d in FIG. 5 is derived according to the minimum fuel consumption rate envelope curve b in FIG.
This envelope curve b is obtained by
This is derived by enclosing the lowest fuel consumption rate points B1 to B10 of the output points P1 to P10.

<< Problems to be Solved by the Invention >> In the above-mentioned conventional technology, which output point P1 to P10 (= C1 to C1
0) is also excellent in that the fuel consumption rate can be minimized.

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

That is, for example, when a short circuit fault occurs in the load,
The value of the detection current IL of the current detector 7x becomes abnormally large, and the value of the target rotational speed N of the engine 1 is calculated from the abnormal value, so that the actual rotational speed of the engine 1 becomes abnormally high.

Then, the abnormal rotation of the engine 1 causes the generator 2
May cause damage or deterioration.
Unnecessary high-speed rotation wastes fuel.

SUMMARY OF THE INVENTION It is an object of the present invention to prevent a generator from deteriorating when a short-circuit failure or the like occurs and to prevent useless high-speed rotation of an engine.

<< Means for Solving the Problems >> The present invention is characterized in that it is configured as follows, for example, as shown in FIG. 1 and FIG.

A. The invention according to claim 1 The generator (2) is connected to the engine (1) in an interlocking manner, and the output voltage of the generator (2) is converted into a DC voltage by the rectifier circuit (4) and then converted by the inverter (5). A voltage is converted into an AC voltage having a predetermined frequency and output from an output terminal (6), and the voltage is detected on the output side or the input side of the inverter (5) by the voltage detection means (7a). The target rotation speed of the engine (1) is calculated by the speed calculation means (8), and the rotation speed adjusting means (9) moves the rotation speed adjustment means (10) of the engine (1) to a position corresponding to the target rotation speed. In the inverter-type engine generator configured to perform the adjustment operation, the rotation speed calculating means (8) comprises voltage comparing means (8a), and the voltage comparing means (8a) is set by the reference voltage setting means (12). Of the voltage detection means (7a) for the reference voltage The voltage is compared. If the detected voltage is low, the rotation speed adjusting means (10) is controlled to the high speed side via the rotation speed adjusting actuator (9), whereas if the detected voltage is high, the rotation speed is adjusted to the low speed side. The control device is configured to perform a control operation, and the rotation speed adjusting actuator (9) is connected to the voltage detection means (7a) via the voltage sudden decrease detection circuit (14).
And a voltage drop detecting circuit (14), based on detecting when the detected voltage of the voltage detecting means (7a) drops rapidly and drastically, based on the detection, the rotation speed adjusting actuator (9) The rotation speed adjusting means (10) is configured to be operated to the idling rotation position via the.

B. Invention of Claim 2 Instead of connecting the rotation speed adjusting actuator (9) to the voltage detecting means (7a) via the voltage sudden decrease detecting circuit (14),
The engine stop means (15) is connected to the voltage detection means (7a) via the voltage drop detection circuit (14), and the voltage drop detection circuit (14) detects the voltage of the voltage detection means (7a) rapidly and In the case that the engine (1) is stopped, the engine (1) is stopped by operating the engine stopping means (15) based on the detection of the drop.

<< Operation >> The present invention operates as follows.

A. Invention of Claim 1 According to the invention of Claim 1, the output performance and the power generation efficiency are reduced due to the difference between the engine and the generator during mass production and the adverse effect in a high-temperature atmosphere. Even when the output performance is lowered, the output voltage acts to maintain the rated voltage.

 Hereinafter, description will be made with reference to FIG.

FIG. 3 shows the change characteristics of the output voltage V with respect to the output current A of the inverter output side circuit 11 for each of the set rotational speeds n1 to n10 of the engine 1, and all of the characteristic curves n1 to n10 have a right-down characteristic. Pass the rated voltage Vo. When the output current A of the inverter output side circuit 11 is 0, the engine 1 is controlled to idle.

Then, when the output current A increases and the output voltage V starts to drop from the rated voltage Vo, the rotation speed adjusting means 10 is operated to the high speed side by the operation of the voltage comparing means 8a to increase the fuel supply amount. Then, the rotation speed of the engine 1 increases,
The characteristic curves n1 to n10 are switched from the left one to the right one, and the output voltage V is immediately changed to the rated voltage Vo.
Is pushed back to.

On the other hand, the output current A decreases and the output voltage V
Begins to rise from the rated voltage Vo, the voltage comparing means 8a operates the rotation speed adjusting means 10 to a lower speed side to reduce the fuel supply amount. Then, the rotation speed of the engine 1 decreases, and the characteristic curves n1 to n10 are switched from the right one to the left one, and the output voltage V is immediately returned to the rated voltage Vo.

Further, when the voltage detected by the voltage detecting means 7a decreases rapidly and significantly abnormally due to the occurrence of a short-circuit failure of the load or the like, the voltage sudden decrease detecting circuit 14 detects this and causes the rotation speed adjusting actuator 9 to operate. The rotation speed adjusting means 10 is operated to the idling rotation position via the engine, and the engine 1 is set to the idling rotation.

B. The Invention of Claim 2 The invention of claim 2 operates almost in the same manner as that of the invention of claim 1, except that the voltage detected by the voltage detecting means 7a is rapidly and significantly abnormal. When it drops,
The engine stop means 15 stops the engine 1.

<< Effects of the Invention >> The present invention is configured and operated as described above, and has the following effects.

A. In the normal operation state, when the voltage on the output side or the input side of the inverter decreases, the control operation is performed so that the engine rotation speed increases. When the voltage on the output side or input side of the inverter drops rapidly and significantly, the engine speed is reduced to idling without increasing the engine speed. It is possible to prevent the rotation speed of the engine from increasing, and to suppress an excessive short-circuit current from flowing into the generator. Therefore, it is possible to prevent the generator or the like from being damaged or deteriorated due to the short-circuit failure, and to prevent the engine from performing useless high-speed rotation at the time of the short-circuit failure to wastefully consume fuel and increase engine noise. .

In addition, since the engine is not stopped, when the power generation is restarted after the repair of the short-circuit failure, the operation of starting the engine can be omitted, and the power generation can be quickly restarted.

B. The Invention of Claim 2 The invention of claim 2 has the same effect as that of the invention of claim 1 in a normal operation state, but the voltage on the output side or the input side of the inverter is rapidly and significantly increased due to a short-circuit failure or the like. The following effects are obtained when the temperature is abnormally lowered.

That is, when the voltage on the output side or the input side of the inverter drops rapidly and significantly abnormally, the engine is stopped without increasing the rotation speed of the engine. It can be suppressed reliably and quickly. In addition, since the engine is stopped in the short-circuit failure state, wasteful consumption of fuel can be reliably suppressed.

<< Example >> Hereinafter, an example of the present invention will be described with reference to the drawings.

Example 1 (See FIGS. 1 and 3) ◎ Prerequisite Structure A three-phase AC generator 2 is connected to an engine 1 in an interlocking manner. The output voltage of the generator 2 is converted to a DC voltage by the rectifier circuit 4, then converted to a predetermined frequency (50 Hz or 60 Hz) by the inverter 5, and output from the output terminal 6.

Based on the detection of the electrical output of the generator 2 by the output detection means 7, the rotation speed calculation means 8 calculates the target rotation speed of the engine 1, and via the actuator drive circuit 21 the rotation speed adjusting actuator. At 9, the rotational speed adjusting means 10 of the engine 1 is adjusted to a position corresponding to the target rotational speed.

特 徴 Characteristic structure 構造 Structure of a part for controlling the rotation speed The output detecting means 7 comprises a voltage detecting means 7a. The voltage detecting means 7a is connected to the circuit 11 on the output side of the inverter 5 to detect the voltage on the output side of the inverter 5.

The rotation speed calculating means 8 comprises a voltage comparing means 8a which is a part of the function of the microcomputer 22. The voltage comparison means 8a compares the detection voltage of the voltage detection means 7a with the reference voltage set by the reference voltage setting means 12, which is a part of the function of the microcomputer 22. If the detected voltage is lower,
Via the drive circuit 21 and the rotational speed adjusting actuator 9, the rotational speed adjusting means 10 is controlled to the high speed side by PID control. On the other hand, if the detection voltage is lower, PI
The control operation is performed to the low speed side by D control.

Thereby, as shown in FIG. 3, the output voltage V of the inverter 5 is maintained at the rated voltage Vo of 100V.

As the rotation speed adjusting actuator 9, a solenoid is used. Instead of this solenoid, an electric or hydraulic servomotor may be used.

The rotation speed adjusting means 10 comprises a speed control lever. The speed control lever is connected via a governor to a throttle lever of a carburetor in the case of a gasoline engine and to a metering rack of a fuel injection pump in the case of a diesel engine. Instead of the speed control lever, the speed control lever may be constituted by the throttle lever or the metering rack.

The structure of the portion for preventing the engine from overrunning The rotation speed adjusting solenoid 9 is connected to the voltage detecting means 7a via the voltage sudden decrease detecting circuit 14 and the actuator driving circuit 21 in this order.
Connect.

The voltage sudden decrease detection circuit 14 comprises a part of the function of the microcomputer 22. When the detected voltage of the voltage detecting means 7a decreases rapidly and significantly, the voltage is detected via the solenoid 9 based on the detection. The speed lever 10 is configured to be operated to the idling position.

Thereby, when the generator 2 or the rectifier circuit 4 or the like is short-circuited or disconnected during operation of the engine generator, the output voltage is detected to be rapidly and greatly reduced, and the engine 1 is reduced to idle rotation. 1 prevents overrun.

The voltage comparing means 8a, the reference voltage setting means 12, and the sudden voltage decrease detecting circuit 14 may be changed to be constituted by analog electric circuits.

Embodiment 2 (see FIGS. 2 and 3) Embodiment 2 shown in FIG. 2 is the same as Embodiment 1 shown in FIG.
Is partially modified as follows.

The voltage detecting means 7a is connected to a circuit 13 on the input side of the inverter 5 instead of being connected to the output circuit 11 of the inverter 5.

An engine stopping means 15 is connected to the voltage detecting means 7a via a voltage sudden decrease detecting circuit 14. Voltage drop detection circuit 14
Is configured to stop the engine 1 by activating the engine stopping means 15 based on the detection of a sudden decrease in the voltage detected by the voltage detecting means 7a.

In the case of a gasoline engine, an engine stop switch that drops the ignition current of the electric ignition device to the ground is used as the engine stopping means 15, and in the case of a diesel engine, a supply / exhaust system interposed in an intake system or an exhaust system is used. Use an electric, hydraulic or pneumatic actuator that closes the shut-off valve or moves the metering rack of the fuel injection pump to the non-injection position.

Third Embodiment In the first embodiment of FIG. 1 described above, the structure of the part for operating the speed control lever 10 to the idling position by the voltage sudden decrease detection circuit 14 via the actuator drive circuit 21 and the rotational speed adjusting solenoid 9. Instead of this, the structure of the part for operating the engine stopping means 15 in the sudden voltage decrease detection circuit 14 described in the second embodiment of FIG. 2 is employed.

Fourth Embodiment In the second embodiment of FIG. 2 described above, instead of the structure of the portion for operating the engine stopping means 15 in the rapid voltage decrease detection circuit 14, the rapid voltage decrease detection circuit described in the first embodiment of FIG. According to 14, the structure of the part for operating the speed adjusting lever 10 to the idling position via the actuator drive circuit 21 and the rotational speed adjusting solenoid 9 is adopted.

[Brief description of the drawings]

FIG. 1 is a block circuit diagram showing Embodiment 1 of the present invention.
FIG. 3 is a block circuit diagram showing a second embodiment of the present invention, and FIG. 3 is an output current / output voltage change characteristic curve diagram showing the control operation of the engine speed in the first and second embodiments. 4 to 6 show an example of the prior art. FIG. 4 is a block circuit diagram, FIG. 5 is a curve diagram for determining an engine speed, and FIG. 6 is a minimum fuel consumption rate envelope curve diagram. 1 ... engine, 2 ... generator, 4 ... rectifier circuit, 5 ...
... Inverter, 6 ... Output terminal, 7 ... Output detection means,
7a: voltage detecting means, 8: rotational speed calculating means, 8a:
Voltage comparison means, 9 ... Rotation speed adjustment actuator, 10 ... Rotation speed adjustment means, 11 ... Inverter output side circuit, 12 ...
Reference voltage setting means, 13 ... Inverter input side circuit, 14 ...
... voltage sudden decrease detection circuit, 15 ... means for stopping the engine.

Claims (2)

(57) [Claims] A generator (2) is linked to an engine (1), and the output voltage of the generator (2) is converted to a DC voltage by a rectifier circuit (4), and then converted to a DC voltage by an inverter (5). Is converted to an AC voltage having a frequency of, and can be output from an output terminal (6). When the voltage on the output side or the input side of the inverter (5) is detected by the voltage detection means (7a), the rotation is performed. The target rotation speed of the engine (1) is calculated by the speed calculation means (8), and the rotation speed adjusting means (10) of the engine (1) is set to the target rotation speed by the rotation speed adjusting actuator (9). In the inverter-type engine generator configured to adjust to a corresponding position, the rotation speed calculating means (8) comprises a voltage comparing means (8a), and the voltage comparing means (8a) is a reference voltage setting means. For the reference voltage set in (12) The detected voltage of the voltage detecting means (7a) is compared, and if the detected voltage is low, the rotational speed adjusting means (10) is controlled to a higher speed via the rotational speed adjusting actuator (9). On the other hand, if it is high, the control operation is performed to the low speed side, and the rotation speed adjustment actuator (9) is connected to the voltage detection means (7a) via the voltage sudden decrease detection circuit (14). The voltage drop detecting circuit (14) is provided with the voltage detecting means (7
a) If the detection voltage drops rapidly and greatly,
Inverter-type engine generator characterized in that, based on the detection thereof, the rotation speed adjusting means (10) is operated to the idling rotation position via the rotation speed adjustment actuator (9). . 2. The rotation speed adjusting actuator (9) is connected to the voltage detection means (7a) via the voltage sudden decrease detection circuit (14).
Instead of connecting the voltage detecting means (7a), means for stopping the engine (15) is connected to the voltage detecting means (7a) via the voltage sudden decrease detecting circuit (14), and the voltage sudden decrease detecting circuit (14) Detection means (7
a) If the detection voltage drops rapidly and greatly,
The inverter-type engine generator according to claim 1, wherein the engine (1) is stopped by activating the engine stopping means (15) based on detection of this.