JPH0270299A - Output controller of engine driven generator - Google Patents

Abstract

PURPOSE:To assure the stable output supply, secured quietness and energy saving by a method wherein either one of intake air or fuel or both of them are controlled so that the engine revolution may be made correspond to the detected load values. CONSTITUTION:A capacitor 6 voltage or a battery 14 voltage as a load detecting means inputted to a controller circuit 33 are compared with the reference voltage by a controller 23 in a gas flow rate control system A 20. Then, a PWM (pulse width modulation circuit) 24 generates waves is duty ratio corresponding to the control amount thereof so that an AND circuit 27a may output said pulse waves when the output from a comparator 26 is high, i.e., an engine is being driven. Through these procedures, a control valve 20 feeds the engine 1 with gas in the amount corresponding to said control amount.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a generator driven by an engine, and particularly to an output control device that controls the output of the generator according to the load.

[Conventional technology]

An engine-driven generator is configured to rotate the generator with a gasoline engine, gas engine, or the like, and output an AC output or a DC output. With conventional engine-driven generators, for example, when extracting DC output, it is common to extract it in a pulsating state that is equivalent to rectifying the output from an AC generator, and when extracting AC output, Generally speaking, the engine speed is kept constant regardless of the size of the engine speed.

(Problems to be solved by the invention) As mentioned above, conventional engine-driven DC generators produce pulsating output that is simply rectified AC output, and are insufficient in terms of stable supply of output. In addition, since conventional engine-driven alternators are set at engine speeds based on high loads, the engine overspeeds at low loads, which is disadvantageous in terms of noise. At the same time, it is also a waste from an energy conservation perspective.

The present invention was made in order to solve the above-mentioned conventional problems, and it is necessary to ensure a stable supply of output and quietness.

Another object of the present invention is to provide an output control device for an engine-driven generator that can save energy.

[Means for solving problems]

The present invention provides an output control device for an engine-driven generator, which includes a means for detecting the magnitude of a load, and a means for detecting the amount of intake air and fuel so that the engine rotational speed becomes a rotational speed corresponding to the detected load value. The invention is characterized by comprising a rotation speed control means for controlling one or both of them.

Here, as the engine in the present invention, a gasoline engine that uses gasoline as fuel and a gas engine that uses gas such as city gas and propane gas as fuel can be employed. When a gasoline engine is used, it is necessary to control the flow rate of both fuel and intake air, but when a gas engine is used, it is not necessarily necessary to control both.
The flow rate of only the fuel may be controlled.

Furthermore, the present invention is applicable to both DC and AC generators.

As a method of controlling the engine speed, when taking out AC output, for example, the voltage level of a capacitor placed between the rectifier circuit and the DC-AC conversion circuit (inverter) is set to a predetermined value, and When extracting DC output, for example, a method can be adopted in which the engine rotational speed is controlled so that the voltage level of the battery becomes a predetermined value.

[Effect]

According to the output control device according to the present invention, the engine rotation speed is controlled so that the output voltage has a value according to the load, so the stability of output supply can be improved. Furthermore, compared to the conventional case where the engine rotation speed is constant, the engine rotation speed at low load is lower, and the average noise level when viewed through the entire load range is lowered, making it possible to improve quietness. Also, since the engine rotates according to the load level,
It is possible to save energy without wasting fuel.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

1 to 3 are diagrams for explaining an output control device for a gas engine-driven AC/DC generator according to an embodiment of the present invention.

In FIG. 1 showing the circuit configuration of the apparatus of this embodiment, 1 is a gas engine that uses gas fuel such as city gas or propane gas, and 2 is a starter for starting the engine 1. 3.
Reference numerals 4 denote three-phase alternating current generators for AC output and DC output, respectively, and each of the generators 3 and 4 includes a rotor coil (not shown) and a stator coil 3a, which are driven by the crankshaft of the engine 1, respectively.

4a, 65a and 5b are rectifiers for rectifying the three-phase alternating current from the generator 3.4, 6 is a load detection capacitor, 7 is an AC ratio scale inch that is turned on when taking out the AC output, and 8 is the rectifier. A DC-AC conversion circuit (inverter circuit) converts the DC from 5a into AC, and 9 is an AC output terminal.

Further, 10 is a bypass switch that is turned on when taking out DC output, 11 is a regulator that adjusts the current flowing through the rotor coil to keep the generated voltage constant, 12 is an operation switch that is turned on when starting operation, 13 is a starter switch,
13a is a starter relay. Further, 14 is a battery, which also serves as a load detection means during DC output. Further, 15 is a DC output switch that is turned on when DC output is performed, and 16 is a DC output terminal.

17 is a manual AC/DC selection switch; 15
a,? a is turned on and off by the selection switch 17;
The above DC output switch 15. These are DC and AC relays that turn on and off the AC output switch 7. Further, 18 is a changeover switch that can be switched between the AC side and the DC side in conjunction with the selection switch 17, 19 is an indicator light that lights up when an output is generated, 20 is a gas control pulp, 21 is an oil pump, and 22 is a glow plug. , these are controlled by a control circuit 33. This control circuit 3
3 is an engine rotation speed control means.

In FIG. 2, which is a block diagram of the control circuit 33, the circuit 33 is a device comprising a gas flow rate control system A, an oil pump control system B, an output control system C, and a glow plug control system. The gas flow control system A operates a gas control valve 20 so that the voltages of the capacitor 6 and the battery 14 as the load detection means match a reference value.
The valve 20 is controlled when the engine is stopped.
This is a system for closing . This control system A includes a p+ controller 23 which compares the voltage of the capacitor 6 or the battery 14 with a reference voltage and outputs a controlled amount; a PWM ( Pulse width modulation circuit)24. It consists of an AND circuit 27a that outputs a high signal when the output from this circuit and an engine operation detection signal to be described later are both high, and an inverting amplifier 28a that inverts the output from this circuit.

The oil pump control system B is for operating the oil pump 21 when the engine is rotating, and includes a converter 25. which converts the generator output from frequency to voltage. A comparator 26 that compares the converted voltage with a reference voltage to detect whether or not the engine is in operation. It consists of an AND circuit 27b2 and an inverting amplifier 28b which re-inputs the comparator output (engine operation detection signal) and the output of the PWM 29 (constant pulse width).

In addition, the output control system C is a system that outputs only when the starter is not operating and the generator output is above a predetermined value, that is, a system that does not output output when the starter is generating electricity. and an inverting circuit 30 that inverts the starter signal that becomes low when the starter is activated. AND circuit 2 which receives the inverted output and the output of the comparator 26 as re-inputs.
7C3 and an inverting amplifier 28C.

Furthermore, the glow plug control system is a system for maintaining the glow plug 22 at a high voltage when starting the engine, and at a low voltage normally to ensure engine ignition and stable rotation, and the voltage of the capacitor, etc. and a voltage control PWM 31. to which the output of the inverting circuit 30 is input. It consists of an amplifier 32.

Next, the effects of this embodiment will be explained.

First, the operation of the control circuit 33 will be explained.

The generator output input to the circuit 33 is converted by the F-V converter 25 in the oil pump control system B, and when the converted voltage is higher than the reference voltage, that is, when the engine is rotating, the generator output is converted by the F-V converter 25. The output from the PWM 29 becomes high, and the AND circuit 27b outputs a constant width pulse wave from the PWM 29, which causes the oil pump 21 to operate via the inverting amplifier 28b.

In addition, the capacitor voltage or battery voltage input to the control circuit 33 is compared with a reference voltage in the controller 23 in the gas flow rate control system A, and the PWM 24 generates a pulse wave with a duty ratio according to the control amount. When the output from the comparator 26 is high, that is, when the engine is rotating, the AND circuit 27a outputs the pulse wave, which causes the gas control valve 20 to control the amount of gas in the engine according to the control amount. 1 will be supplied.

In the output control system C, when the starter switch is off, the switch signal is inverted by the inverter 30 and becomes high, and when the output of the comparator 26 is high, that is, when the generator output is above a predetermined value, the output of the AND circuit 27c is becomes high, and as a result, the output lamp 19 lights up, and
Output relay a or 15a is turned on.

Furthermore, in the glow plug control system, when the starter switch is turned on, the output from the voltage side iPWM 31 is supplied to the glow plug 22 via the amplifier 32, thereby increasing the glow voltage when starting the engine.

Next, the operation of the entire control device will be described with reference to FIG. 3, first when an AC output is taken out. When the operation switch 12 is turned on and the AC/DC selection switch 17 is selected to the AC side (AC relay 7a side), the changeover switch 18 is switched to the AC side in conjunction with this.

Note that the bypass switch IO is turned off.

As a result, the control circuit 33 controls the glow plug 2.
2 is supplied with a low voltage (see time t1 in FIG. 3). If you turn on the starter switch 13 in this state,
The voltage to the glow plug 22 increases, the engine 1 begins to rotate, and the oil pump 21 starts operating (t in the same figure).
2) When the engine speed increases and the detected voltage reaches the target voltage, the AC relay 73 is energized, the AC output switch 7 is turned on, and the output lamp 19 is lit (t3 in the figure).

And AC power generation! The three-phase AC from 3 is rectified by a rectifier 5a, and then passed through a DC-AC conversion circuit 8 to an output terminal 9.
It will be taken out from. Note that when the starter switch 13 is released, the glow plug voltage is maintained at a low voltage.

When the load increases, the capacitor voltage decreases, the control circuit 33 outputs a pulse wave with a duty ratio corresponding to the difference between the reference voltage and the capacitor voltage, and the gas flow rate increases. When the engine rotation speed increases and the capacitor voltage returns to a predetermined value, the engine rotation speed is maintained at that value (t4 to t5 in the figure).

Note that when the load voltage increases abnormally, even if the duty ratio is maximized, the engine rotation speed commensurate with the load cannot be obtained.
If the capacitor voltage decreases, the engine 1 will stop, the gas control valve 20 will close, and the oil pump 21 will also stop (L6 to t7 in the same figure).
.

Also, if you are extracting AC output as described above,
The output from the DC generator 4 is stored in the battery 14 via the regulator 11.

Next, when taking out DC output, the changeover switch 17 is switched to the DC side. Then, in conjunction with this, the bypass switch 10 is also turned on.

Further, the DC relay tSa turns on the DC output switch 15, and the three-phase AC from the DC side generator 4 is rectified by the rectifier 5b and then taken out from the output terminal 16 via the bypass switch 10° output switch 15. Become. Then, the voltage of the battery 14 is compared with the reference voltage, and the gas control valve 20 is controlled to open or close depending on the difference between the pressures on both sides.

In this way, in this embodiment, the engine rotational speed is controlled by changing the gas flow rate so as to obtain the target voltage in response to load fluctuations, so that a stable supply of output can be realized. In addition, since the engine speed is controlled according to the load, compared to conventional systems that control the engine speed to a constant speed, the engine does not rotate more than necessary, especially at low loads (and quietness is improved accordingly). At the same time, it is possible to save energy by not consuming more fuel than necessary.

By the way, in conventional devices for controlling the engine rotational speed to a constant value as described above, mechanical rotational speed control is generally performed using a governor. On the other hand, when performing electrical rotational speed control according to the above-described embodiment, it is very easy and reliable to control the rotational speed at a constant level.

Figures 4 and 5 show an example of an electric control device that controls the engine speed to a constant level. In the figures, the same reference numerals as in Figures 1 and 2 indicate the same or equivalent parts. .

Gas flow rate control system A' of the control circuit 34 of this embodiment
Then, the output of the alternating current generator is subjected to frequency-to-voltage conversion by the F-V converter 25, and the converted voltage is compared with a reference voltage by the P-controller 35, and a control amount is output. The generator output corresponding to the target engine speed is adopted as this reference voltage. When the output from the engine operation detection circuit 36 is high (indicating that the engine is operating), the AND circuit 27
a outputs a pulse wave with a pulse width corresponding to the control amount determined from the converted voltage and the reference voltage, thereby controlling the gas control valve 20 via the inverting amplifier 28a. Note that 38 is a correction circuit that corrects the reference voltage at the time of starting.

In the oil pump control system B', the engine operation detection circuit 3
When the output from PWM 6 is high, a pulse wave with a constant width is output from PWM 29, and oil pump 21 is operated.

In the output control system C', the comparison circuit 37 compares the converted voltage with a predetermined engine speed (for example, 4800 rpm11).
When the rotation speed is higher than the rotation speed, the output lamp 19 lights up and any output relay a is turned on.

15a is energized. Furthermore, in the glow plug control system D', the voltage applied to the glow plug 22 increases while the starter is operating.

In this control circuit 34, the reference voltage is set to a voltage corresponding to the target engine rotation speed, and the gas flow rate is controlled so that the target engine rotation speed is obtained. Compared to rotational speed control, control is easier, more reliable, and has higher control accuracy.

In the above embodiments, the case of both AC and DC type has been described, but the present invention can of course be applied to AC generator and DC generator alone type.

〔Effect of the invention〕

As described above, according to the output control device for an engine-driven generator according to the present invention, the engine rotation speed is controlled so that the predetermined target voltage is changed in response to fluctuations in the load voltage, so that the stability of the output can be improved. In addition, the engine rotational speed does not become higher than necessary especially at low load, which reduces operating noise and saves energy.

[Brief explanation of the drawing]

1 to 3 are diagrams for explaining an output control device according to an embodiment of the present invention, in which FIG. 1 is a block diagram thereof, FIG. 2 is a block diagram of its control circuit portion, and FIG. FIG. 3 is a waveform diagram for explaining the operation, and FIGS. 4 and 5 are block diagrams for explaining the present invention in detail. In the figure, 1 is the engine, 3 and 4 are the generators, and 6.14
3 is a capacitor 5 battery (load detection means), and 33 is a control circuit (rotation speed control means). Patent Applicant Yamaha Motor Co., Ltd. Agent Patent Attorney Tsutomu Shimofu Figure 1 Figure 3 - °C

Claims (1)

[Claims] (1) A device that controls the output of a generator driven by an engine according to the load, and includes a load detection means for detecting the size of the load, and either the amount of intake air or fuel supplied to the engine. 1. An output control device for an engine-driven generator, comprising: a rotational speed control means for controlling one or both of the engine rotational speeds in accordance with the detected load value.