JP2008038868A - Engine generator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an engine generator by which in the case of application/interruption of a heavy load, a coefficient of instantaneous frequency-fluctuation can be suppressed, and power-supply to a load larger than a conventional method can be stably effected. <P>SOLUTION: The engine generator is provided with an AC synchronous generator 12, a diesel engine 11 for driving the generator, an electronic governor 14 of a speed-governing means to keep the engine speed constant, and a switch 18 for switching the output of the generator. The engine generator is provided further with a switch controller 19 which outputs a switch-operation signal S2 for opening/closing the switch 18 after outputting an electronic-governor control signal S3 for accelerating/decelerating the engine speed by the electronic governor 14. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an engine power generation device, and more particularly to an engine power generation device that drives an AC synchronous generator with an engine to supply power at a constant frequency to a load, and is used particularly for power supply to various loads. The present invention relates to a portable engine power generator.

  In an engine generator that drives an AC synchronous generator with an engine such as a diesel engine, it is required that the fluctuation rate of the frequency supplied from the generator to a load such as a motor is small, and the moment when a constant load is turned on and off In many cases, the frequency variation rate is set to ± 10% or less. Therefore, the engine speed is detected, and the fuel injection amount is adjusted on the basis of the detected speed, so that the engine speed, that is, the output frequency is kept constant regardless of the load fluctuation. Means, for example, an automatic governor called an electronic governor is provided.

Furthermore, in order to respond quickly to large load fluctuations, the load fluctuation detection means provided on the output side of the generator detects rapid fluctuations in the load, and the engine is forcibly controlled according to the magnitude of the load fluctuation. An apparatus has been proposed (see, for example, Patent Document 1).
JP 7-238847 A

  However, even in the control device described in Patent Document 1, since the feedback control is performed after the fluctuation occurs, it is inevitable that the frequency fluctuates greatly at the moment of a large load fluctuation. Therefore, in order to reduce the instantaneous frequency variation rate, it is conceivable to limit the load, employ a large engine with a sufficient engine output, or increase the gain and responsiveness of the electronic governor. However, if the load is limited, the application of the power generation device will be limited. If a large engine is used, the device cost and running cost will increase, and if the gain and responsiveness of the electronic governor are increased, the stability will decrease. Hunting may occur.

  Therefore, the present invention provides an engine power generator that can suppress an instantaneous frequency fluctuation rate when a large load is turned on or off, and can stably supply power to a larger load than before. It is intended to provide.

  In order to achieve the above object, an engine power generator according to the present invention includes an AC synchronous generator, an engine that drives the generator, speed control means for keeping the rotation speed of the engine constant, and an output of the generator. An engine generator including a switch that opens and closes is provided with a switch control means for outputting an opening / closing signal of the switch after outputting an acceleration / deceleration signal of the speed control means.

  In addition, when the switch control means outputs a closing signal to the switch, the switch control means outputs a closing signal after a predetermined time from outputting a speed increasing signal to the speed control means, and opens the signal to the switch. Is output, a decelerating signal is output to the speed control means, and an open signal is output after a predetermined time.

  Further, the present invention is characterized in that a plurality of the switches are provided, and the switch control means is provided in the switch connected to the load having the maximum load amount when the load amount of the load connected to each switch is different. Yes.

  According to the engine power generator of the present invention, since the speed increase / decrease signal is output to the speed control means before the switch is opened / closed, the engine speed is increased / decreased. Can be kept small. As a result, it is possible to stably supply power even to a large load that cannot be used because the frequency fluctuation rate exceeds 10% in the conventional power generator.

  FIG. 1 is a single-line diagram showing an embodiment of the engine power generator of the present invention. This engine power generator is for generating electric power by driving an AC synchronous generator 12 with a diesel engine 11 or the like, and an automatic voltage regulator 13 for keeping a voltage supplied to a load such as a motor or lighting constant, A speed control means for adjusting the engine speed and keeping the output frequency constant, for example, an electronic governor 14 is provided.

  Further, the power generator shown in this embodiment has two output terminals 15 and 16, and one of the output terminals 15 has a relatively small load amount and a small load fluctuation during ON / OFF. A load such as an electric appliance is connected, and the other output terminal 16 has the largest load amount among the loads connected to the power generator, and the load such as a motor with a large load fluctuation at ON / OFF (maximum Load) is connected.

  Further, switches 17 and 18 are provided in the wiring of the output terminals 15 and 16, respectively, and a manual switch is used for the switch 17 on the output terminal 15 side to which a general load is connected. Is closed. On the other hand, as the switch 18 on the output terminal 16 side to which the maximum load is connected, an electromagnetic switch that opens and closes by a switch control signal S1 from the switch control means 19 is used.

  The switch control means 19 is operated by an ON signal and an OFF signal (switch operation signal) S2 from the switch 20 and outputs the switch control signal S1 to the switch 18 and also the electronic governor 14. Output an acceleration / deceleration signal (electronic governor control signal) S3. The output timing of the switch control signal S1 to the switch 18 and the electronic governor control signal S3 to the electronic governor 14 is set by a time limit circuit, and when the switch operation signal S2 is input from the switch 20 After the electronic governor control signal S3 is output to the electronic governor 14, the switch control signal S1 to the switch 18 is output after a predetermined time has elapsed.

  That is, the switch control means 19 outputs an acceleration signal as the electronic governor control signal S3 to the electronic governor 14 when receiving the ON signal as the switch operation signal S2 from the switch 20, and after a certain time has elapsed, the switch 18 outputs a closing signal as a switch control signal S1. When an OFF signal is received from the open / close switch 20, an open signal is output to the switch 18 after a predetermined time has elapsed since the deceleration signal was output to the electronic governor 14.

  The time from the output of the electronic governor control signal S3 to the output of the switch control signal S1 is set in consideration of the response of the diesel engine 11, rotational energy including the diesel engine 11 and the AC synchronous generator 12, and the like. When the engine speed increases by 3 to 7% by outputting an acceleration signal to the electronic governor 14, or when the deceleration signal is output by 3 to 7% by outputting a deceleration signal to the electronic governor 14. It is preferable to set so as to output a signal or an open signal, and it is usually desirable to set in the range of 0.1 to 0.3 seconds. Note that if the rate of increase or decrease in engine speed is less than 3%, the effect of providing the switch control means 19 cannot be fully exhibited, and if the rate of increase or decrease exceeds 7%, the frequency fluctuation range is sufficient. May not be able to be made smaller.

  The engine power generation device formed in this manner generally has a frequency corresponding to the use region, for example, 50 Hz in the eastern Japan region, 60 Hz in the west Japan region is set as the rated frequency, and the rated voltage is 200 V when the rated frequency is 50 Hz. At 60 Hz, each is set to 220V. The electronic governor 14 sets the rotational speed of the diesel engine 11 to a rotational speed corresponding to the rated frequency, for example, 1500 rotations per minute when the rated frequency is 50 Hz, and 1800 rotations per minute when the rated frequency is 60 Hz.

  When the load variation is small, for example, when a load is connected only to the output terminal 15, the automatic voltage regulator 13 and the electronic governor 14 operate in response to the load variation, and the voltage and frequency are kept constant. The automatic voltage regulator 13 detects the voltage output from the synchronous generator 12 by the voltage detector 21, and according to the detected voltage, the main generator field magnet (not shown) via the exciter field coil 22 of the synchronous generator 12. The output voltage is kept constant by adjusting the field current applied to the coil (field winding). The electronic governor 14 keeps the output frequency constant by adjusting the fuel injection amount of the diesel engine 11 in accordance with the frequency detected by the frequency detection function of the electronic governor itself.

  When a maximum load, for example, a motor is connected to the output terminal 16 to start the operation, when the ON / OFF switch 20 is operated to output an ON signal to the switch control means 19, the switch control means 19 immediately sends a speed increase signal. Output to the electronic governor 14, the electronic governor 14 generates a signal for increasing the fuel injection amount of the engine separately from the signal from the normal current transformer 23, and increases the rotational speed of the diesel engine 11. Further, the switch control means 19 outputs a closing signal to the switch 18 after elapse of 0.2 seconds, for example, when a certain time set in the time limit circuit has elapsed after outputting the acceleration signal to the electronic governor 14.

  As a result, when the rotational speed of the diesel engine 11 increases to some extent, for example, about 5%, the switch 18 is closed, and power is supplied from the output terminal 16 to the motor. When the load on the generator 12 increases suddenly due to the motor starting current (rush current), the rotational speed of the diesel engine 11 decreases instantaneously. However, the electronic governor 14 is activated and a predetermined engine rotational speed, that is, rated The fuel injection amount is increased so as to maintain the frequency. At the same time, the output voltage also drops instantaneously, but the automatic voltage regulator 13 is activated to increase the field current so as to maintain the rated voltage.

  Further, when the motor is stopped, the switch control means 19 that has received the OFF signal from the open / close switch 20 immediately outputs a deceleration signal to the electronic governor 14, and the electronic governor 14 is a signal for reducing the fuel injection amount of the engine. Is sent to the diesel engine 11 to reduce the engine speed. The switch control means 19 outputs an open signal to the switch 18 after elapse of 0.2 seconds, for example, when a certain time set in the time limit circuit has elapsed after outputting the deceleration signal to the electronic governor 14.

  As a result, when the rotational speed of the diesel engine 11 decreases to some extent, for example, about 5%, the switch 18 is opened, the power supply from the output terminal 16 to the motor is cut off, and the load on the generator 12 is rapidly reduced. To do. At this time, the rotational speed of the diesel engine 11 increases instantaneously, but the engine speed is maintained at a predetermined rotational speed and the rated frequency is maintained by operating the electronic governor 14 to reduce the fuel injection amount. . At the same time, the output voltage also rises momentarily, but the automatic voltage regulator 13 operates to decrease the field current so as to maintain the rated voltage.

  FIG. 2 is an explanatory diagram showing an example of the fluctuation state of the output frequency when the maximum load is connected to the output terminal 16 of the engine power generator of this embodiment. First, when the open / close switch 20 is turned on, a speed increasing signal is output as an electronic governor control signal, and the frequency increases as the fuel injection amount increases and the engine speed increases (A). When the switch 18 is closed and a load is applied after a certain period of time, the frequency decreases instantaneously due to an increase in the load amount (B), but a signal for increasing the fuel injection amount from the electronic governor 14 that has detected a decrease in the frequency. Is continuously output to the engine to increase the engine speed (C). When the motor start-up current disappears and the frequency approaches the rated frequency, the electronic governor 14 is activated according to the increase or decrease in the other load connected to the output terminal 15, and the frequency is in a settling state where the rated frequency is maintained. (D)

  When the open / close switch 20 is turned OFF, a deceleration signal is output as an electronic governor control signal, and the frequency decreases as the fuel injection amount decreases and the engine speed decreases (E). When the switch 18 is opened after a certain period of time and the load is cut off, the frequency increases instantaneously due to a rapid decrease in the load amount (F), but a signal for decreasing the fuel injection amount from the electronic governor 14 continues. It is output to the engine, and the engine speed is decreased to control the frequency to the rated frequency (G).

  FIG. 3 is an explanatory diagram showing an example of the fluctuation state of the output frequency in a conventional engine power generator having the same specifications except that the switch control means 19 is not provided. In the conventional engine power generation device, when the switch is closed and a load is applied, the frequency decreases instantaneously due to an increase in the load amount (J). Therefore, the electronic governor increases the fuel injection amount by feedback control and the engine speed is increased. Is raised to return to a predetermined frequency (K). When the switch is opened and the load is cut off, the frequency increases instantaneously due to the decrease in the load amount (L). Therefore, the electronic governor reduces the fuel injection amount to decrease the engine speed, so that the predetermined frequency is reached. Return (M).

  2 is compared with FIG. 3, the frequency fluctuation range, which is the difference between the highest value and the lowest value of the frequency, is higher in the engine power generator of the present invention shown in FIG. 2 than in the conventional engine power generator shown in FIG. It turns out that it is about half. For example, assuming that the rated frequency is 60 Hz and the instantaneous frequency fluctuation rate at the time of loading / cutting off the load is ± 10%, that is, ± 6 Hz, in FIG. 3, the output frequency is reduced from 60 Hz to 54 Hz by loading the load. The output frequency is increased from 60 Hz to 66 Hz by cutting off, and the frequency fluctuation width is 12 Hz.

  On the other hand, in the case of FIG. 2, when the engine speed is increased before the load is applied, for example, when the load is applied when the output frequency reaches 63 Hz, the output frequency decreases only to 57 Hz even if the load is the same 6 Hz. It will be. Similarly, if the engine speed is reduced before the load is cut off, for example, the load is cut off when the output frequency reaches 57 Hz, the output frequency will only rise to 63 Hz even if the same 6 Hz rise, The frequency fluctuation width is 6 Hz.

  Therefore, the fluctuation of the output frequency to the load connected to the other output terminal 15 can be suppressed to be small, and malfunction due to the frequency fluctuation can be prevented. In addition, when the instantaneous frequency variation rate is set to ± 10%, as described above, the conventional engine power generation device can use only a load with an instantaneous frequency variation rate of up to ± 6 Hz. Then, by appropriately setting the output frequency (engine speed) at the time of turning on the load and at the time of cutting off the load, a load whose instantaneous frequency fluctuation rate reaches ± 12 Hz can be used. That is, when the load is turned on after raising the output frequency to 66 Hz before turning on the load, the output frequency is reduced by 12 Hz to 54 Hz, but it is in the range of −10% with respect to the rated frequency of 60 Hz. If the load is cut off after the output frequency is lowered to 54 Hz, even if the output frequency is increased by 12 Hz, it is 66 Hz, so that the range is + 10% with respect to the rated frequency of 60 Hz.

  The automatic governor for controlling the diesel engine 11 can also use a general mechanical governor, and the open / close switch 20 receives an external signal such as an operation switch attached to the motor. It can also be configured to operate with a signal. Furthermore, the engine power generation device of the present invention is most suitable for a portable engine power generation device in which a load is not specified, but can also be applied to a service generator or an emergency power generator corresponding to a specific load. Moreover, the switch control means 19 can be easily formed using a known timed circuit.

It is a single wire connection figure showing an example of one form of an engine power generator of the present invention. It is explanatory drawing which shows an example of the fluctuation state of the output frequency in the engine electric power generating apparatus of this example. It is explanatory drawing which shows an example of the fluctuation state of the output frequency in the conventional engine generator.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Diesel engine, 12 ... AC synchronous generator, 13 ... Automatic voltage regulator, 14 ... Electronic governor, 15, 16 ... Output terminal, 17, 18 ... Switch, 19 ... Switch control means, 20 ... Switch DESCRIPTION OF SYMBOLS 21 ... Voltage detector, 22 ... Exciter field coil, 23 ... Current transformer, S1 ... Switch control signal, S2 ... Switch operation signal, S3 ... Electronic governor control signal

Claims (3)

  An engine generator comprising: an AC synchronous generator; an engine that drives the generator; a speed control unit that keeps the engine speed constant; and a switch that opens and closes the output of the generator. An engine power generator comprising a switch control means for outputting a switch opening / closing signal after outputting an acceleration / deceleration signal of the speed control means.   When the switch control means outputs a closing signal to the switch, it outputs a closing signal after a predetermined time from outputting a speed increasing signal to the speed control means, and outputs an opening signal to the switch. 2. The engine power generator according to claim 1, wherein an open signal is output after a predetermined time from outputting a deceleration signal to the speed control means.   A plurality of the switches are provided, and when the load amount of the load connected to each switch is different, the switch control means is provided in the switch connected to the load having the maximum load amount. Item 3. The engine power generator according to Item 1 or 2.

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