JP2000087778A - Engine power generating equipment control unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control unit for engine power generating equipment that minimizes frequency at which an engine speed command value is updated when there are fluctuations in load. SOLUTION: A voltage detector 32 outputs a voltage it has detected as a load representative value. An engine control unit 16 reads the load-representative value data at predetermined time intervals to compute a speed command value. The engine control unit 16 performs arithmetic operations of the target value of the speed of an engine 11 at intervals shorter than the predetermined ones according to the speed command value. It thereby controls the supply of fuel to the engine 11 so that the engine speed can be tapered down to this target value. Load fluctuations over a smaller range are handled by adjusting the conducting angle of rectification means of a converter 13. Electric power in short supply is automatically compensated for by a commercial power source or other AC power system.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine power generation equipment control apparatus for reducing the frequency of changing the engine speed command as much as possible to extend the life and improve fuel efficiency.

[0002]

2. Description of the Related Art In recent years, the necessity of protecting the global environment has been publicized, and attention has been paid to a distributed power supply device such as an engine power generation device or a cogeneration device as a private power generation facility. In these power generation equipment devices, an increase in the electric load is detected, and the engine speed is controlled in accordance with the electric load.

[0003]

In the above-described apparatus, it is generally determined whether the output from the engine generator with respect to the load is insufficient based on the load current value of the engine generator. A dedicated current detection sensor for detecting the load current has been required. In addition, since the operating state such as the number of revolutions of the engine is frequently changed in accordance with the fluctuation of the electric load, there is a problem that it is not easy to maintain a high operating efficiency and to reduce a NOx gas emission and the like. . Further, since the internal combustion engine generally has a response delay to control, frequent changes in the operating state cause overshoot and hunting, and there is a problem that a countermeasure is required. Also, fluctuations in the engine speed cause noise and low-frequency vibrations, and also shorten the life of the engine.

An object of the present invention is to solve the above-mentioned problem by enabling load fluctuation to be detected by simple means and by minimizing the frequency of updating the engine speed command value when a load fluctuation occurs. An object of the present invention is to provide a control device for a power generation facility.

[0005]

According to the present invention, there is provided an engine power generation equipment control device, comprising: means for detecting a magnitude of an electric load based on a voltage applied to an electric load supplied with electric power from the engine generator; A means for outputting a rotation speed command value corresponding to the electric load detected based on the rotation speed at every scheduled time; and an engine control means for rotating the engine at a constant speed based on the rotation speed command value. There is.

According to the above feature, the engine generator is rotated at a constant speed by the engine to generate a constant electric power. When the electric load changes under the constant output, the output voltage of the engine generator changes. Therefore, the magnitude of the load is determined by detecting the output voltage. Then, a rotational speed command value is output at predetermined intervals according to the load fluctuation, and the engine is operated based on the rotational speed command value.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram showing the configuration of one embodiment of the present invention. Engine generator 10
Includes an (internal combustion) engine 11 and a generator 12 mechanically connected to each other, and drives the generator 12 by the engine 11 to generate an alternating current having a frequency and a voltage corresponding to the engine speed. The output AC is converted by the converter 13 into the first voltage Veg.
, And supplied to the input of the inverter 30 via the backflow prevention diode 14.

The gate control unit 15 is supplied with a predetermined target or set voltage Veg0 (for example, 190 V) and the first voltage Veg, and converts the measured actual output voltage Veg of the converter 13 into the set voltage Veg0. The conduction of the thyristor forming the converter 13 is controlled by a known appropriate method so as to be equal. With such a configuration, the output voltage Veg of the converter 13 is maintained at the set voltage Veg0 in a predetermined output current range of the converter 13.

If the conversion efficiency is not taken into account, the output power of the generator 12 is immediately the output power of the inverter 30. Therefore, for example, when the rotation speed of the engine 11 is 2000 rpm, the output power is 2 kW, and the electric load 3
Assuming that the rated voltage on the fifth side is 200 V, inverter 30 outputs a current of 10 A by constant current output control (CI control). Here, when the electric load 35a is added and the total electric load increases (that is, the load impedance decreases) and a load current of 11A is required, 2 KW
In the maximum output, when 11 A is output from the inverter 30, the terminal voltage on the electric load 35 side drops to about 182V. When the electric load further increases and a load current of 12 A is required, the terminal voltage drops to about 167V.
As described above, when the load current exceeds the predetermined value, the inverter 3
Since the output voltage of 0 is determined by the output power of the generator 12, the terminal voltage of the electric load is determined by the magnitude of the electric load.

Therefore, in this embodiment, the voltage detector 32 is provided on the output side of the inverter 30, and the voltage V detected by the voltage detector 32 is set to a value (load voltage) representative of an electric load.
Is input to the engine control unit 16. The engine control unit 16 supplies the detected voltage (load voltage signal)
V, a deviation from the rated voltage is calculated, and based on the deviation, the engine speed signal Net
That is, a fuel signal is generated.

The function and operation of the engine control unit 16 will be described in detail with reference to the block diagram of FIG. 4 and the flowchart of FIG. The load stability determination unit 60 determines whether or not the electric load 35 is stable in accordance with a criterion and a method to be described later (step S11 in FIG. 5), and determines that the load is stable and the V timer 61 is set. Scheduled time (for example, 1 second, but can be set appropriately according to the situation,
If the measurement has not been completed for a certain period of time, the load voltage sampling section 62 is triggered by the output of the V timer 61 to take in the load voltage signal Vi (steps S12 and S13). When the load is unstable, V timer 6
Regardless of the state of 1 (or at shorter time intervals), the load voltage signal Vi is acquired.

The voltage drop calculating section 69 has a rated voltage (for example, 2
00V), ie the deviation of the voltage signal Vi, ie, the voltage drop V
Calculate d. The voltage drop Vd is the Ne0 setting table 63
The engine speed adjustment value Ne0 required to maintain the rated voltage is read from the Ne0 setting table 63 based on the voltage drop Vd (step S14).
It is supplied to the calculation functions 65a to 65c of the Neo correction unit 65 (step S16). Instead of the table, the engine speed adjustment value Ne0 may be calculated by a known formula prepared in advance. The scheduled time has not yet elapsed and V timer 6
If the time has not elapsed, steps S13 and S14 are skipped, and the engine speed adjustment value Ne is skipped.
Reading of 0 and operation are not performed. Therefore, in the subsequent engine speed target value calculation operation, the engine speed determined based on the engine speed adjustment value Ne0 specified last time is used as it is as the target value.

The conduction angle sampling section 64 includes an α timer 7
Every time 5 counts up (step S15: shorter time than the V timer, for example, every 5 ms), the conduction angle sampling unit 64 is triggered and the gate control unit 1
5 is sampled, and the detected value αi is taken in (step S16). The detected value αi is supplied to the comparing unit 76, and is compared with the upper limit Y and the lower limit X of the conduction angle transferred from the upper / lower limit memory 77 (step S17).

The conduction angle is determined by the AC / DC converter 13
It is represented by the on-time duty ratio (%) of the rectifier thyristor (not shown) in the inside. If the conduction angle αi is larger than the upper limit value Y% (for example, 85%), it means that the engine tends to be overloaded with respect to the current electric load, that is, there is a possibility that the generated power is insufficient. Correction unit 65
Is added to the output Ne0 from the setting table 63 by a predetermined correction value .DELTA.Ne2 to generate a new engine speed adjustment value Neo (step S1).
8).

On the other hand, when the conduction angle αi is smaller than the lower limit value X% (for example, 75%), it means that the power supply from the engine generator 10 is excessive for the current electric load. From the calculation function 6 of the Ne0 correction unit 65
5b, a predetermined correction value ΔNe1 is obtained from the output Ne0.
Is subtracted to generate a new engine speed adjustment value Ne0 (step S19). When the conduction angle αi is between the lower limit value X and the upper limit value Y, a practically appropriate power generation amount is obtained for the electric load.
Sets the obtained engine speed adjustment value Ne0 as a new engine speed adjustment value Net as it is (step S
20) It is natural that the above-mentioned △ Ne1 and △ Ne2 may be set to the same value.

The Net output unit 66 updates the engine speed target value Net by adding the new engine speed adjustment value Ne0 obtained as described above, and supplies the updated engine speed target value Net to the fuel calculation unit 67 where the fuel signal is output. And supplied to the engine 11 (step S21). The Net output unit 66
Outputs a new engine speed target value Net, the output number counter 68 is incremented. Until the counter 68 reaches the scheduled number of times (for example, three times), the scheduled time by the α timer 75 (for example, 5 ms)
The detection of the conduction angle value and the update of the rotation speed target value Net are repeated every time.
The timer 61 is started and is restored to the initial state (steps S22 and S23).

In the above description, the engine speed target value Net is converted into a fuel signal. Instead, the engine speed target value Net is converted into other data such as the throttle opening and the speed control is executed. Of course it is also good. Further, the engine speed target value Ne calculated in steps S16 to S20.
Instead of outputting t at each time in step S21, an appropriate representative value (for example, a simple average value or a weighted average value) for the predetermined number of times determined in step S22 is output in step S22.
Alternatively, the representative value may be output as the target rotational speed Net when the determination in step S22 is affirmative.

As described above, since the update control of the engine speed command value in response to the fluctuation of the electric load is performed in a relatively long cycle, the time ratio in which the engine is operated at a substantially constant speed becomes longer, and Effects such as NOx conversion, longer engine life, reduced noise generation, and improved fuel economy can be expected.

Next, a method for determining load stability will be described. The determination of the load stabilization (step S11) can be made based on the presence or absence of the following load instability element, but is not limited to this, and it is obvious that the determination may be made by another appropriate method. It is. 1. In the determination in step S17 in FIG. 5, the routine in which the conduction angle α is equal to or greater than Y and the routine in which the conduction angle α is equal to or less than X are alternately continued for a predetermined number of times (for example, three times). 2.
The case where the increase and decrease of the rotational speed command value Ne0 read from the setting table 63 are alternately repeated over a predetermined number of times during a certain number of times. 3. When the amount of protrusion of the conduction angle α from the upper limit Y or the lower limit X exceeds a predetermined value.

The engine generator 10 of FIG. 1 is shown as constituting a cogeneration system having an engine exhaust heat recovery means. The liquid cooling device 17 of the engine generator 10 may be a known suitable one, and a cooling liquid (for example, water or ethylene glycol) is circulated by the pump P1 to absorb the heat generated by the engine or the generator and cool it. The coolant whose temperature has increased by this is supplied to the heat exchanger 19, and after heating the water supplied from the outside by the pump P2, it is used again for cooling the engine and the generator. The feed water warmed by the heat exchanger is supplied to the heat load 33, and is used as, for example, hot water or a heat source for heating. Of course, making a cogeneration device is not an essential requirement of the present invention, but merely shows that the present invention can be applied to a cogeneration device.

The present invention can be applied to a case where a plurality of engine generators are interconnected. FIG. 2 is a block diagram showing an outline of an example in which four engine generators are interconnected,
1 denote the same parts. However, for the sake of simplicity, the engine generator devices indicated by reference numerals 10 to 13, 15 and 16 in FIG.
Reference numerals 0, 300, and 400 indicate portions related to heat, and illustration thereof is omitted.

In FIG. 2, the output DC voltage set values Veg1, Veg2, Veg3, Vg of each converter are set in order to smoothly and uniquely transfer the load sharing of each engine generator.
It is desirable not to make eg4 the same, but to have a difference between them. For example, if Veg1>Veg2>Veg3>Veg4> Vac, as can be easily understood from the above description, first, the engine generator device 100 having the highest voltage set value bears the load 35, and the load 35 increases. Accordingly, the engine generator devices 200, 300, and 400 bear the load in order. Adjustment control of the amount of power generation by each engine generator device when the load fluctuates, that is, control of the rotation speed of each engine, is performed in the same manner as described above.

In such a device, the load sharing ratio of each engine generator is automatically determined according to the characteristics of each power supply without any control means. Simplified. Furthermore, even if the output of the engine generator decreases due to aging or deterioration, load sharing according to the current power generation stress is performed automatically. It becomes possible to do.

As another control method of the engine generator, as described above, the target output voltage of each generator is not set independently of the power generation capacity or capacity thereof. The voltage may be set high to load the load preferentially.

Further, as shown by a frame surrounded by a dotted line in FIG. 2, an output voltage memory 37, a deterioration judging unit 38, and a display alarming unit 39 are added to each of the power generating units when a fixed rotational speed command is given. The AC or DC output voltage values are stored in the memory 37 at appropriate time intervals, and the rate of change and / or the amount of change of the output voltage value are monitored by the deterioration determination unit 38. Is exceeded, the deterioration or failure of the generator may be determined, and the display / warning unit 39 may display the deterioration or failure and / or generate an alarm.

FIG. 3 shows a conceptual diagram of the structure of all devices when the embodiment of FIG. 2 is applied to a cogeneration system. In the figure, the same reference numerals as those in FIGS. 1 and 2 indicate the same or equivalent parts. Since the configuration of each generator device is the same, only one generator device 100 is denoted by the reference numeral.

The generator unit has a maintenance panel 41 on the front or side surface, an ECU for controlling each component, an air cooling fan and fins, a liquid cooling thin tube (both not shown), etc. including. The engine exhaust gas is discharged from the exhaust port 49. The cooling air is taken in from the intake 42, and the air warmed inside is discharged from the outlet 43. The liquid cooling thin tube is connected to one end of each of a cooling liquid supply pipe 45 and a return pipe 46, and a heat medium such as water or ethylene glycol is circulated in these pipes by a pump P1.

The other ends of the pipes 45 and 46 are connected to the heat exchanger 19.
Linked to The heat exchanger 19 is provided with a water supply pipe 4 for exchanging heat with a high-temperature heat transfer medium supplied through a pipe 46.
7 and one end of the hot water pipe 48 are connected, and water is supplied by a pump P2. The other ends of the water supply pipe 47 and the hot water pipe 48 are connected to a heat load 33, and supply the heat of the hot water obtained by the heat exchanger 19 to the heat load (a heater, a water heater, or the like) 33.
When the heat load consumes hot water such as hot water supply, it goes without saying that the water supply is performed from the outside.

Each engine generator 100, 200, 3
The alternating currents generated in 00 and 400 are supplied to the corresponding converters 13A, 13B, 13C and 13D to be converted into DC of a predetermined voltage. Automatic voltage regulator 5
0 controls the direct current to the inverter 30 so that the output AC voltage of the inverter 30 becomes a set value (100 V in this example). The automatic voltage regulator 50 also supplies the operating voltage for the ECU in each engine generator.
The general controller 51 communicates with the automatic voltage regulator 50 and each ECU via a communication line 52, and appropriately controls each operation. An operation panel 54 can be used by an operator.

[0030]

As is apparent from the above description, according to the present invention, since the rotational speed command value is input at each scheduled time, frequent changes in the rotational speed can be avoided, and the constant speed rotation time can be avoided. Increase the percentage. As a result, frequent changes in the operating state are eliminated, overshooting and hunting are prevented, and a longer engine life, lower NOx, and improved fuel economy can be achieved. On the other hand, when the fluctuation of the electric load is remarkable, the rotation speed target value can be updated at short time intervals to follow the load. In addition, the current detection means for detecting the magnitude of the load of the engine generator becomes unnecessary,
The configuration is simplified.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention.

FIG. 2 is a block diagram showing another embodiment of the present invention.

FIG. 3 is a conceptual diagram showing the structure of all devices when the embodiment of FIG. 2 is applied to a cogeneration system.

FIG. 4 is a functional block for calculating an engine speed command value and a target value according to the present invention.

FIG. 5 is a flowchart showing a procedure for calculating an engine speed command value and a target value according to the present invention.

[Explanation of symbols]

10, engine generator, 13, 23 ... converter,
15, 25: gate control unit, 16: engine control unit,
Reference Signs List 30 inverter, 32 voltage detector, 35 electric load, 61 V timer, 62 load current sampling unit, 63 Neo table, 64 conduction angle sampling unit, 65 Ne0 correction unit, 66 Net output unit , 67 ... Fuel operation unit

 ──────────────────────────────────────────────────続 き Continued on front page F term (reference) 3G093 AA16 BA14 BA17 BA19 BA20 BA32 CA05 DA00 DA01 DA14 DB19 DB23 EA03 EA05 EB09 FA02 FA03 FA07 FA11 FB01 FB02 5H004 GA03 GA16 GA28 GA37 GA38 GB12 HA08 HA14 HB08 HB14 JA03 KA22 KA22 KC56 LA15 MA29

Claims (4)

[Claims] 1. An engine power generation equipment control device including an engine generator driven by an engine, means for detecting a magnitude of the electric load based on a voltage applied to an electric load supplied with electric power from the engine generator. A means for outputting a rotational speed command value corresponding to the electric load detected based on the output voltage for each scheduled time; and an engine control means for rotating the engine at a constant speed based on the rotational speed command value. An engine power generation equipment control device, characterized in that: 2. An engine control unit comprising: a target value calculation unit configured to calculate a target rotation speed of the engine at a time interval shorter than the scheduled time based on the rotation speed command value; 2. The engine power generation equipment control device according to claim 1, further comprising means for controlling fuel supply to the engine such that a deviation from the target value is reduced. 3. The system according to claim 1, wherein the supply interval of the rotational speed command value is adjusted to be long when the electric load is stable, and to be short when the electric load is unstable.
Or the engine power generation equipment control device according to 2. 4. A rectifier for converting an alternating current generated from the engine generator to a direct current, and a means for adjusting a conduction angle of the rectifier in response to a change in the electric load, 4. The engine power generation equipment control device according to claim 3, wherein it is determined that the electric load is unstable when the conduction angle exceeds a predetermined range.