JP2001317393A - Engine controller for engine power generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrence of hunting in engine rotation for load fluctuation. SOLUTION: A comparison part 9 comparing the number of revolutions of an engine with a target value of revolutions to output its control deviation, and an adjusting part 10 amplifying the control deviation to control a stepping motor 6 and the rotation of the engine 1 are provided to constitute a feedback control system. The adjusting part 10 is provided with a proportional element outputting a signal proportional to the control deviation and adjusts offset of a throttle 4 so that the throttle 4 is fully opened when a gain of the proportional element is zero. The gain of the proportional element is increased or decreased and is set to such gain that fluctuation of engine rotation from no load time to rated load time of load applied on a power generator 2 is within 4 to 6%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine control for an engine for driving a generator, which has excellent responsiveness to quickly recover to a predetermined rotation speed with respect to a load change on the generator side. It concerns the device.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 8, an engine 1 for driving a generator 2 is provided with a mechanical governor (governor) 3 for controlling the rotation of an engine for driving the generator. The throttle 4 is mechanically adjusted based on the engine speed detected by the governor 3 to control the rotation of the engine 1 to a predetermined speed, and the load 5 on the generator 2 side fluctuates. Even if it occurs, the voltage generated by the generator 2 and the frequency thereof are kept constant.

[0003]

In the configuration of the conventional engine control device for an engine generator shown in FIG. 8, the mechanical governor 3 is used to mechanically adjust the throttle 4 of the engine 1. When the load 5 fluctuates, it takes time to recover the voltage generated by the generator 2 and its frequency, and when the relationship between the load and the engine throttle 4 changes when the engine 1 ages, The fine adjustment cannot be performed, and even if the fine adjustment can be performed, it takes time to recover the generated voltage of the generator 2 and its frequency, and there is a disadvantage that the response is poor.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned drawbacks by driving the throttle of an engine by a stepping motor, detecting the rotation of the engine on the generator side, for example, by the generated voltage waveform, and detecting the generated voltage. The number of revolutions of the generator detected by the waveform, that is, based on the detected number of revolutions of the engine, while applying feedback so that the generated voltage of the generator and its frequency become constant, the gain of the proportional element of the feedback control system is 4-6% variation in engine speed from no load to rated load applied to the generator
Is set to a value that falls within the range, thereby improving the resilience of the generated voltage of the generator and its frequency. And, in order to improve the responsiveness of the engine rotation returning to the target rotation speed, feed forward control is introduced based on the power generated by the generator, and there is no control method that automatically controls the throttle of the engine via a stepping motor, It is an object of the present invention to provide an engine control device for an engine generator that has excellent responsiveness of the engine to load fluctuations on the generator side, and thus has excellent resilience of the generator voltage and its frequency.

[0005]

In order to solve the above-mentioned object, an engine control apparatus for an engine generator according to the present invention controls the number of revolutions of an engine driving a generator to a predetermined number of revolutions. In the machine engine control device, a stepping motor that controls an engine, a throttle opening of a throttle that determines the rotation of the engine, a stepping motor drive unit that drives the stepping motor, and a frequency of a generator that is driven by the engine are detected. A rotational speed detecting means for detecting the rotational speed of the engine, and a comparing section for comparing the rotational speed of the engine detected by the rotational speed detection means with a preset target rotational speed of the engine, and outputting a control deviation thereof. Amplifies the control deviation output from the comparison unit and controls the stepping motor via the stepping motor drive unit And a control unit for controlling the rotation of the engine via a throttle to form a feedback control system. The control unit includes a proportional element that outputs a signal proportional to the control deviation output from the comparison unit. When the gain of the proportional element is zero, the offset of the throttle is adjusted so that the throttle is fully opened or fully closed, and the gain of the proportional element is increased or decreased. It is characterized in that the gain is set so that the engine rotation fluctuation applied to the snow generator from no load to rated load falls within 4 to 6%.

Further, a load amount detecting means for detecting the magnitude of the load on the generator, and a target rotational speed for which the engine rotational speed is substantially predetermined by a load having the magnitude detected by the load amount detecting means. A throttle opening offset signal generating means for changing to a throttle offset amount corresponding to a throttle opening to be obtained, a throttle opening offset signal generated by the throttle opening offset signal generating means, and a throttle output from the adjusting section. An adder is provided between the adjusting unit and the stepping motor driving unit for adding the opening output signal, and the response is improved by using the feedforward control together.

[0007] Further, a differential element is provided in the adjusting section, the number of revolutions of the generator is detected, and the detected amount is differentiated by the differential element and added to the offset amount of the throttle. And the integral value of the deviation obtained by the integral element is added to the throttle offset amount.

[0008] From no load applied to the generator to the rated load, an experiment is conducted to determine whether or not the engine quickly reaches the target speed by using the adjusting section only with the proportional element. It has been newly found that the gain is such that the engine rotation fluctuation from no load to rated load is within 4 to 6%.

That is, as a result, it has been found that the gain of the proportional element selected so that the rotation fluctuation at the rated load with respect to the no-load state is 4 to 6% is optimal.

More specifically, the proportional element alone is 4%
Attempts to achieve smaller engine speed fluctuations (at rated load versus no load) will cause hunting of the engine. At greater than 6%, engine performance will not be fully exploited and generator output will be reduced. Was.

Therefore, if feedforward control is introduced under the optimum value of the gain of the proportional element of the feedback control system, and a differential element and / or an integral element is added together with the proportional element, the responsiveness of the engine is further improved. Is done.

[0012]

FIG. 1 is a block diagram showing an embodiment of an engine control device for an engine generator according to the present invention.

In FIG. 1, 1 is an engine, 2 is a generator, 4 is a throttle, 6 is a stepping motor, 7 is a stepping motor driving unit, 8 is a rotation speed detecting means, 9 is a comparing unit, and 10 is an adjusting unit. ing.

An engine generator engine control device according to the present invention for controlling the number of revolutions of the engine 1 that drives the generator 2 to a predetermined number of revolutions, includes the engine 1 having the throttle 4 and the engine 1. Stepping motor 6 that controls the throttle opening of throttle 4 that determines rotation
And a stepping motor drive unit 7 for driving the stepping motor 6 and a frequency based on a generated voltage waveform of an AC output output from the generator 2 driven by the engine 1 to detect a frequency thereof and detect a rotation speed of the engine 1. Revolution detecting means 8
Is compared with the rotation speed of the engine 1 detected by the rotation speed detecting means 8 and a rotation target value (set rotation speed) of the engine 1 preset in the next comparing section 9, and the control deviation (throttle opening) is determined. And a control deviation output from the comparison unit 9 to control the stepping motor 6 via the stepping motor drive unit 7 and to rotate the engine 1 via the throttle 4. A closed loop is formed with the adjustment unit 10 for controlling the feedback control, and a feedback control system is formed.

The adjusting section 10 is provided with a proportional element for outputting a signal proportional to the control deviation outputted from the comparing section 9, and when the gain of the proportional element is zero, the throttle is adjusted. For example, the offset of the throttle 4 is adjusted so as to be in a fully open state (applicable even when fully closed), and the gain of the proportional element is increased or decreased so that the load applied to the generator 1 is reduced. The gain is set so that the engine rotation fluctuation up to the rated load falls within 4 to 6%.

When the gain of the proportional element of the adjusting unit 10 is zero, the throttle 4 is fully opened (or fully closed) when the gain of the proportional element is zero, and the offset of the throttle 4 is adjusted. The gain of the element is increased (or decreased), and the gain is set such that the rotation fluctuation between no load and rated load is 4 to 6%.

FIG. 2 is a block diagram showing an embodiment of a stepping motor driving section for driving a stepping motor.

In FIG. 1, reference numeral 12 denotes a stepping motor drive circuit, 13 denotes a stepping motor drive pulse generation circuit, 14 denotes a stepping motor position monitor, and 15 denotes a comparison unit.

The stepping motor driving circuit 12 is a driver for operating the stepping motor 6, and the stepping motor driving pulse generating circuit 13 generates pulses of an amount for operating the stepping motor 6 via the stepping motor driving circuit 12. The stepping motor position monitor 14 outputs the signal from the stepping motor driving pulse generation circuit 13 to the stepping motor driving circuit 1.
2, the comparator 15 compares the throttle opening signal from the controller 10, that is, the control deviation with the number of pulses detected by the stepping motor position monitor 14, and compares the difference between the two. A pulse is generated from the stepping motor drive pulse generation circuit 13 so as to become zero, and control for opening and closing the throttle 4 of the engine 1 to a predetermined position via the stepping motor 6 is performed.

In the engine control device for an engine generator according to the present invention, the gain of the proportional element of the control unit 10 is varied from 4 to 6 from no load applied to the generator to a rated load. %, The gain is set within the range from no load to rated load, and the dotted line display width 4 to 6% in the load-rotational speed characteristic diagram shown in FIG.
The engine 1 does not hunt and the engine performance can be sufficiently brought out.

As described above, if an attempt is made to achieve an engine rotation fluctuation of less than 4% (at the time of rated load versus no load) by the proportional element of the adjusting unit 10 in FIG. As a result, the engine performance cannot be sufficiently brought out and the output of the generator 2 is reduced.

Therefore, the control method of the engine control apparatus for the engine generator according to the present invention shown in FIG.
Next, a description will be given of an engine control apparatus for an engine generator according to the present invention in which the gain of a proportional element within% is set to further improve the response of the engine.

FIG. 3 is a block diagram showing another embodiment of the engine control apparatus for an engine generator according to the present invention.

In the figure, the same components as those in FIG. 1 are denoted by the same reference numerals, and the engine 1, the generator 2, the throttle 4, the stepping motor 6, the stepping motor driving unit 7, the rotation speed detecting means 8, the comparing unit 9 , The adjusting unit 10 shown in FIG.
, And the stepping motor drive unit 7 has the same function as the configuration shown in FIG.
Reference numeral 16 denotes a load amount detecting unit, 17 denotes a throttle opening offset signal generating unit, and 18 denotes an adding unit.

The load amount detecting means 16 detects, for example, the magnitude of the load on the generator 2 by using the AC output of the generator 2 and the voltage and current.

Throttle opening offset signal generating means 1
Reference numeral 7 denotes a throttle which corresponds to a throttle opening at which, for example, an experiment is performed in advance and the rotation speed of the engine 1 under the load corresponds to the target rotation speed which is set in advance in response to the magnitude of the load of the generator 2. The throttle opening offset signal to be changed to the offset amount of 4 is stored in the memory, and the memory is accessed with the load having the magnitude detected by the load amount detecting means 16, and the rotation speed of the engine 1 of the load is reduced. A throttle opening offset signal for changing to an offset amount of the throttle 4 corresponding to a throttle opening which should become a preset target rotational speed is read out from the memory and output. Alternatively, based on the magnitude of the load detected by the load amount detecting means 16, the offset amount of the throttle 4 corresponding to the throttle opening degree at which the rotation speed of the engine 1 at the time of the load should be substantially equal to the preset target rotation speed May be obtained by calculation.

The adding section 18 has a function of adding the throttle opening offset signal generated by the throttle opening offset signal generating means 17 and the throttle opening output signal output from the adjusting section 10. It is provided between 10 and the stepping motor drive unit 7.

The load amount detecting means 16, the throttle opening degree offset signal generating means 17 and the adding section 18 detect a change in the throttle opening degree of the engine 1 due to the load fluctuation when the load fluctuates in the generator 2. A so-called feed-forward control is generated in which the throttle opening offset signal is generated from the throttle opening offset signal generating means 17 assuming in advance and corresponding control is performed. The responsiveness of the engine is further improved as compared with the configuration shown in FIG.

Although the adjustment unit 10 in FIGS. 1 and 3 has been described with only the proportional element, the adjustment unit 10 includes a proportional element 19, a differential element 20 and / or an integral element 21 as shown in FIG. May be provided to improve the responsiveness of the engine. Reference numeral 23 denotes a low-pass filter for removing noise.

The differential element 20 detects the number of revolutions of the generator 2, differentiates the detected amount by the differential element 20, and adds the output of the proportional element 19 to the adder 22, so that the response of the engine is improved. Can be improved.

Further, in the integral element 21, the integrated value of the control deviation obtained by the integral element 21 is added to the output of the proportional element 19 by the adder 22, so that the responsiveness of the engine can be improved.

FIG. 6 shows an embodiment of an engine control device for an engine generator according to the present invention.

In the figure, the same components as those in FIG. 1 are denoted by the same reference numerals, 24 is a generator, 25 is an inverter,
6 is a microcomputer, 27 is a rotation speed calculator, 28
Denotes a PID output unit, 29 denotes a load calculation unit, and 30 denotes a feedforward control system.

The generator 24 driven by the engine 1 has three
A three-phase AC voltage generated by the generator 24 is converted into an AC voltage having a desired frequency by an inverter 25 and supplied to a load.

The microcomputer 26 includes a generator 24
The data of the voltage waveform is fetched from one phase of the three-phase AC voltage generated in step (1), and the data of the voltage waveform and current waveform converted into the AC voltage having the desired frequency from the inverter 25 are fetched.

The rotation speed calculator 27 of the microcomputer 26 detects the rotation speed of the generator 24, that is, the rotation speed of the engine 1, from the data of the voltage waveform of the three-phase AC voltage generated by the generator 24. And the PID output unit 28
Based on the rotation speed of the generator 24 of the rotation speed calculation unit 27, that is, the rotation speed of the engine 1, the proportional element 1 described in FIG.
9, a throttle opening output signal obtained by adding the respective outputs from the differentiating element 20 and the integrating element 21 is output.

On the other hand, the load calculator 29 of the microcomputer 26 calculates the magnitude of the load applied to the generator 24 from the data of the voltage waveform and the current waveform converted into the AC voltage of the frequency generated by the inverter 25. Ask by. Then, the feedforward control system 30 sends the throttle opening offset signal from the throttle opening offset signal generating means 17 described with reference to FIG. 3 based on the load variation obtained by the load calculating section 29 based on the load fluctuation. Generate.

Then, the microcomputer 26 generates the throttle opening offset signal described with reference to FIG. 3 and supplies the signal to the stepping motor 6 via the stepping motor driving section 7. Thereby, the stepping motor 6 controls the throttle 4 of the engine 1 and is quickly controlled so that the rotation speed of the engine 1 becomes the set rotation speed.

FIG. 7 is a characteristic diagram according to the difference in control method when a load change occurs.

FIG. 4 shows a conventional governor control characteristic using only a proportional element. The deviation of the rotation speed after a load change is large and does not return to its original value even after a lapse of time. Is a control characteristic in the case of a PID in which the feedforward control system described above is added, but the gain of the proportional element is poor, and it oscillates after a load change and takes time to converge. Adds the feedforward control system described above, and setting the gain of the proportional element is the optimal PID control characteristic, and minimizes the rotational speed deviation after load change and the time required to return to the original.

From this characteristic diagram, it is understood that if the feedforward control system is used in combination with the feedback control system and the gain of the proportional element is set to the optimum PID, the responsiveness of the engine is improved.

[0042]

As described above, according to the present invention, the engine speed fluctuation at the rated load with respect to the no-load condition is 4-6.
As we set the gain of the proportional element that fits in%,
Hunting of the engine and insufficient performance of the engine do not cause a situation in which the output of the generator is reduced.

The feed-forward control system is used in combination with the feedback control system, and the gain of the proportional element is set so that the engine rotation fluctuation at the rated load with respect to the no-load condition is within 4 to 6%. Can be further improved. If a differential element or an integral element is added to this control method, the responsiveness of the engine can be further improved.

[Brief description of the drawings]

FIG. 1 is a block diagram of an embodiment of an engine control device for an engine generator according to the present invention.

FIG. 2 is a block diagram of an embodiment of a stepping motor driving unit that drives a stepping motor.

FIG. 3 is a block diagram of another embodiment of the engine control device for the engine generator according to the present invention.

FIG. 4 is a block diagram of an embodiment of an adjusting unit.

FIG. 5 is a load-rotational speed characteristic diagram illustrating a gain of a proportional element in which engine rotation does not cause hunting.

FIG. 6 shows a configuration of an embodiment of an engine control device for an engine generator according to the present invention.

FIG. 7 is a characteristic diagram according to a difference in a control method when a load change occurs.

FIG. 8 shows a configuration of a conventional engine control device for an engine generator.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 engine 2 generator 4 throttle 5 load 6 stepping motor 7 stepping motor driving unit 8 rotation speed detecting means 9 comparing unit 10 adjusting unit 12 stepping motor driving circuit 13 stepping motor driving pulse generating circuit 14 stepping motor position monitor 15 comparing unit 16 load Amount detecting means 17 Throttle opening degree offset signal generating means 18 Adder 19 Proportional element 20 Differential element 21 Integral element 24 Generator 25 Inverter 26 Microcomputer

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) F02D 45/00 322 F02D 45/00 322 362 362L (72) Inventor Masao Ikui Hayakawa character, Hayakawa, Nitta-cho, Nitta-gun, Gunma Prefecture 3rd address Sawafuji Electric Co., Ltd. Nitta Plant F term (reference) 3G065 BA02 CA15 DA06 DA13 EA07 FA08 FA11 FA14 GA00 GA10 KA36 3G084 AA06 BA03 BA05 CA03 CA04 DA04 DA11 EB13 EC03 FA33 3G093 AA16 BA02 BA14 CA04 DA01 FA05 3G301 KA07 JA06 KA09 LA03 NA08 ND05 ND42 PE01Z

Claims (4)

[Claims] An engine control apparatus for an engine generator for controlling the number of revolutions of an engine driving a generator to a predetermined number of revolutions, wherein the stepping control controls an engine and a throttle opening of a throttle that determines the number of revolutions of the engine. A motor, a stepping motor drive unit for driving a stepping motor, a rotation speed detection means for detecting a frequency of a generator driven by the engine and detecting a rotation speed of the engine, and an engine speed detected by the rotation speed detection means. A comparison unit that compares the number of revolutions with a preset rotation target value of the engine, outputs a control deviation thereof, amplifies the control deviation output from the comparison unit, and amplifies the stepping motor via the stepping motor driving unit. And a control unit for controlling the rotation of the engine via a throttle. The control unit is configured to include a proportional element that outputs a signal proportional to the control deviation output from the comparison unit, and when the gain of the proportional element is zero, the throttle is fully opened. Alternatively, the offset of the throttle is adjusted so as to be in the fully closed state, and the gain of the proportional element is increased or decreased, and the engine rotation fluctuation from no load applied to the generator to the rated load is reduced by 4%. An engine control device for an engine generator, wherein the gain is set to be within 6%. 2. The engine control device for an engine generator according to claim 1, wherein the load amount detecting means for detecting the magnitude of the load on the generator, and the load having the magnitude detected by the load amount detecting means. Throttle opening signal generating means for changing the rotation speed of the throttle to an amount of throttle opening corresponding to a throttle opening that should become a target rotation speed set in advance, and a throttle generated by the throttle opening offset signal generating means. An addition unit is provided between the adjustment unit and the stepping motor drive unit for adding the opening offset signal and the throttle opening output signal output from the adjustment unit, and the responsiveness is improved by using the feedforward control together. An engine control device for an engine generator, characterized in that it is improved. 3. The engine control device for an engine generator according to claim 1, wherein a differential element is provided in the adjusting section, a rotational speed of the generator is detected, and the detected amount is differentiated by the differential element. An engine control device for an engine generator, wherein the control value is added to a throttle offset amount. 4. The engine control device for an engine generator according to claim 1, wherein an integral element is provided in the adjusting section, and an integral value of a deviation obtained by the integral element is added to an offset amount of the throttle. An engine control device for an engine generator, characterized in that: