JPH1141993A - Integrated control method for engine generator and its device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an integrated control method for an engine generator and its device capable of supplying high quality electric power with less fluctuation of voltage and frequency, even if a load changes abruptly. SOLUTION: An integrated control method is constituted, in such a way that the load torque of an engine 1 corresponding to the effective power of the load is calculated to be added to the torque command value, while the reactive power of a load is absorbed by a reactive power generating function 25 connected to the load circuit. Also, an integrated control device, provided with a power-calculating function 22, which calculates the effective and reactive power from the output voltage and load current of a generator, a load torque calculating function 23, an adding function 24 and the reactive power generating function 25, which generates the reactive power corresponding to the reactive power value calculated by the power-calculating function 22, is constituted so as to calculate the load torque of the engine 1 corresponding to the effective power of the load, to add it to a torque command value and to absorb the reactive power of the load by the reactive power generating function 25.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and a device for controlling an engine-driven generator driven by an engine, and more particularly to a method for reducing voltage fluctuation and frequency fluctuation even when the generator load fluctuates. The present invention relates to an integrated control method of an engine-driven generator capable of supplying electric power of high quality and a device thereof.

[0002]

2. Description of the Related Art An engine-driven alternator (hereinafter referred to as an engine-driven generator or generator) driven by an engine is used as an emergency power source or a power source used in an area where commercial power is not supplied. I have. Such an engine-driven generator control device is configured, for example, as shown in FIG. In FIG. 3, reference numeral 1 denotes an engine,
The generator 2 is being driven. 1a is a rotation speed sensor for detecting the engine rotation speed, and 2a is an exciter. Generator 2
Is supplied to the load 3 via a safety device such as a circuit breaker 3a or a switch.

[0003] In the governor Gv for controlling the rotation speed of the engine 1 to a predetermined value, a rotation speed command value ω instructed from a higher-level function of a system including the engine-driven generator.
s is compared with the current rotation speed ω of the engine 1 detected by the rotation speed sensor 1a by the comparison function 4, and the deviation speed component is amplified by the servo amplification function 5 having a predetermined performance, and the torque command for engine rotation control is obtained. The actuator 6 of the fuel injection pump of the engine is driven as the value τs. The actuator 6 drives and operates the rack position of the fuel injection pump 7. Therefore, the fuel injection pump 7 injects an amount of fuel determined by the rack position into each cylinder at an appropriate timing set and adjusted in advance, based on the angle of the rack position and the crankshaft (not shown) of the engine.
That is, the rack position is controlled by the governor Gv, and the engine 1
, The current rotation speed ω of the engine 1 is controlled to match the rotation speed command value ωs, and the power generation frequency of the generator 2 is maintained at the set frequency.

An automatic voltage regulator AVR for controlling the generated voltage of the generator 2 to a predetermined value (in FIG. 3, enclosed by a dashed line)
In, a voltage command value Vs commanded from a higher-level function or the like of a system including the engine-driven generator is compared with a detection voltage V proportional to a generated voltage of the generator 2 described later by a comparison function 8. The deviation voltage component is amplified by a servo amplification function 9 having a predetermined performance, input to a power amplification function 10 as a field voltage command value Vfs of the exciter 2a and amplified, and the obtained field voltage value Vf is excited. 2a. On the other hand, as a function of detecting the generator voltage, the instrument transformer 11 converts the generated voltage at a predetermined ratio to obtain an AC voltage v, and the AC voltage v is rectified by the rectifying function 12 and is proportional to the generated voltage. Is obtained. That is,
The detection voltage V obtained by the generator voltage detection function is input to the comparison function 8 described above. Therefore, the generator 2 is controlled so as to match the voltage command value Vs.

[0005]

Incidentally, the engine has a stroke from intake to exhaust during its rotation.
The time required for this step causes a delay in the above-described control function, resulting in a dead time. Because of this dead time, the governor control gain is also restricted, and a sufficient response characteristic as a governor cannot be obtained. for that reason,
When the load changes abruptly, the fluctuation of the rotation speed increases. Therefore, the fluctuation of the power generation frequency of the generator becomes large. When the generator is a synchronous machine, the internal voltage of the synchronous generator is large, so that when the load current changes, the output voltage also changes. Even if the output fluctuation is detected, the output voltage does not change immediately even if the field voltage is changed due to the large time constant. Therefore, when the load changes abruptly, the voltage fluctuation increases. The present invention solves the above-mentioned problems (problems) of the prior art, and can supply high-quality power with little voltage fluctuation and frequency fluctuation even when there is a sudden change in load. An object of the present invention is to provide a generator integrated control method and a device thereof.

[0006]

In order to solve the above-mentioned problems, an integrated control method for an engine-driven generator according to the present invention calculates a load torque of an engine corresponding to the active power of a load and converts the calculated load torque into a torque command value. In addition, the reactive power of the load is absorbed by the reactive power generation function connected to the load circuit. In this case, it is preferable that a phase-advancing capacitor is connected to the load circuit so that the reactive power generation function functions for a reactive power of a predetermined value or more set in accordance with the rated capacity of the phase-advancing capacitor. In addition, the integrated control device for the engine-driven generator to which the above method is applied, the engine-driven generator has a power calculation function for calculating active power and reactive power from the generator output voltage and the load current, and the power calculation function. A load torque calculation function for calculating a load torque from the obtained active power, an addition function for adding the load torque calculated from the torque calculation function to a torque command value, and a reactive power value calculated from the power calculation function A reactive power generation function for generating a corresponding reactive power, the load torque of the engine corresponding to the active power of the load is calculated and added to a torque command value, and the reactive power of the load is absorbed by the reactive power generation function. Configured. In this case, it is desirable to connect a phase-advancing capacitor to the load circuit to which the reactive power generation function is connected, and to set the rated capacity of the reactive power generation function in accordance with the rated capacity of the phase-advancing capacitor. Furthermore, it is more desirable that the rated capacity of the reactive power generation function be the same as the rated capacity of the phase advance capacitor. Furthermore, a comparison function is provided for comparing a predetermined value set in accordance with the rated capacity of the phase advance capacitor with the reactive power value calculated by the power calculation function. It is effective to configure the power generation function to function.

[0007] The engine drive generator to which the above-described method is applied and to which the basic configuration of the present invention which constitutes the control device is applied, has a small voltage fluctuation and frequency fluctuation even when there is a sudden change in the load, and provides high-quality electric power. Can supply. In the above basic configuration, when a phase-advancing capacitor is connected to the load circuit, the reactive power can be controlled by effectively utilizing the reactive power generation function. For example, if the rated capacity of the phase-advancing capacitor and the rated capacity of the reactive power generation function are the same, the controllable reactive power can be doubled economically. Further, when the reactive power generation function is configured to function for a reactive power value equal to or more than a predetermined value,
The reactive power generation function and the phase advance capacitor can be more effectively utilized.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to FIGS. 1 and 2, the same reference numerals as those in FIG. 3 denote the same or similar element functions as those described in the related art, and a detailed description thereof will be omitted. Further, illustration of element functions and wirings that are unnecessary for explanation of the basic functions of the present invention and that are mounted on a general engine-driven power generator are omitted. First Embodiment: In FIG. 1, reference numeral 20 denotes an integrated control function configured based on the present invention, which connects an instrument current transformer 21, a power calculation function 22, and a load torque calculation function 23 as shown in the figure. Be composed. 24 is an addition function, and 25 is a reactive power generation function.

In the integrated control function 20, first, a voltage v proportional to the output voltage of the generator 2 and a voltage i proportional to the load current detected by the current transformer 21 are input to the power calculation function 22. The power calculation function 22 calculates the active power value and the reactive power value supplied from the generator 2 to the load 3 by calculating from the amplitude and phase difference of the input voltage v and the voltage i. 22 has a calculation function for calculating and calculating an active power value and a reactive power value from a signal indicating a voltage and a load current (hereinafter referred to as a power calculation function 2).
2 is referred to as a detected active power value P, and the reactive power value is referred to as a detected reactive power value Q). The detected active power value P calculated by the power calculation function 22
To enter. The engine torque ω is input to the load torque calculation function 23. Accordingly, the load torque calculation function 23 calculates the output torque value τL of the engine by calculating from the input detected active power value P and the engine rotation speed ω. That is, the torque calculation function 23 has a calculation function of dividing the detected active power value P by the engine rotation speed ω to calculate the torque from the power and the rotation speed, and, if necessary, a power generation used for accurate torque value calculation. It is assumed that the efficiency characteristics and the like of the machine are set and recorded in advance. Load torque calculation function 2
The output torque value τL calculated by the third function is
4, the torque command value τs output from the servo amplification function 5
And a torque command value τss corrected according to the load amount is obtained. Therefore, the actuator 6 of the fuel injection pump 7 of the engine 1 is driven by the corrected torque command value τss. Therefore, the fuel injection pump 7 moves the rack position to each cylinder at an appropriate timing which is adjusted and set in advance based on the position of a rack (not shown) operated by the actuator 6 and the angle of the crankshaft (not shown) of the engine. Inject the amount of fuel determined by Therefore, the rotation speed of the engine 1 is controlled according to the change in the load amount.

[0010] The detected reactive power value Q calculated by the power calculating function 22 is input to the reactive power generating function 25 to control the reactive power generated by the reactive power generating function 25. The reactive power generation function 25 has a function of continuously and rapidly generating and generating reactive power by the semiconductor power conversion element. Generally, a load generates reactive power with a delay. When the reactive power generation function 25 outputs a leading reactive power having the same value as the reactive power generated in the load circuit, the reactive power component of the load 3 becomes reactive power. It will be absorbed instantaneously by the generating function 25. That is, since the reactive power of the load is absorbed by the reactive power generation function 25, the reactive power component occupying the main part causing the output voltage drop based on the internal impedance of the generator is not output. Therefore, the fluctuation of the generated voltage of the generator due to the load fluctuation is excluded.

Second Embodiment A second embodiment will be described with reference to FIG. The difference between the second embodiment and the first embodiment is that the detected reactive power value Q is compared with a preset reactive power reference value Qs by a comparing function 26 as shown in FIG. Reference value Qs and detected reactive power value Q
Is input to a reactive power generation function 25 to generate reactive power, and a phase advance capacitor 27 is connected to the output circuit of the generator 2. Therefore,
When the reactive power reference value Qs is made equal to the rated capacity of the phase advance capacitor 27, the reactive power generation is performed until the detected reactive power value Q exceeds the reactive power reference value Qs equal to the rated capacity of the phase advance capacitor 27. The function 25 outputs delayed reactive power. The reactive power generated in the load is absorbed by the phase advance capacitor. When the detected reactive power value Q exceeds the reactive power reference value Qs, the reactive power generating function 25 advances the reactive power. The excess reactive power that is output and cannot be absorbed by the phase advance capacitor is absorbed by the reactive power generation function 25. That is, the reactive power of the load is absorbed by the phase-advancing capacitor and / or the reactive power generation function 25, and the fluctuation of the power generation voltage of the generator due to the load fluctuation is removed.

As described above, the power factor of the load is usually delayed. On the other hand, the reactive power generation function
The reactive power can be controlled and generated continuously during the advanced rated power factor. In order for the reactive power generation function to completely absorb the reactive power of the load and reduce the reactive power output by the generator to zero, the reactive power generation function proceeds to control and generate the reactive power. At this time, as long as the power factor of the load is delayed, the reactive power generation function only needs to control and generate only the reactive power. Therefore, in this case, the delayed reactive power generated by the reactive power generation function is not used and is wasted. Therefore, an inexpensive phase-advancing capacitor is connected in parallel with the reactive power generation function to advance the power factor at the time of no load, so that the delayed reactive power of the reactive power generation function can be effectively used. At this time, if the rated capacity of the phase advance capacitor is set to the rated capacity of the reactive power generation function, the controllable reactive power obtained by combining the reactive power generation function and the phase advance capacitor can be extended from 0 KVar to twice the rated capacity. Therefore, for example, a rated capacity of 250 KVa
r, the reactive power to be controlled by combining the reactive power generation function applied to the power generator with a power factor of 0.8 and the rated capacity of the advanced phase condenser is 0 KVar to 250 KVar × (1 ² −0.8 ² ).
^{1/2, that} is, 0 KVar to 150 KVar. Therefore, 7
The reactive power generation function of 5 KVar and the phase-advancing capacitor of 75 KVar can continuously control and absorb the reactive power of 0 KVar to 150 KVar. Therefore, in this case, the reactive power reference value Qs described with reference to FIG.
Var may be set.

The configuration described with reference to FIG. 2 shows an example of the usage in the case where the phase advance capacitor is combined with the reactive power generation function, and utilizes the function of combining the reactive power generation function and the phase advance capacitor. A function for setting the reactive power generation function, a rated capacity of the phase-advancing capacitor, and a processing function for the detected reactive power value Q input to the reactive power generation function, for example, a circuit function such as appropriately changing and setting the function of the comparison function May be appropriately configured.

The above description shows the basic configuration and functions for realizing the technical idea of the present invention, and is appropriately applied in accordance with the conditions and specifications of the engine driven generator to which the present invention is applied. Needless to say, it can be modified. For example,
The excitation function of the generator may form a correction function corresponding to the excitation function, and the governor function of the engine may form a correction function corresponding to the governor function of the engine. Further, the load torque calculation function 23 is a simple constant gain circuit in a system where the rotation fluctuation is relatively small, and a low-cost circuit using the rotation speed command value ωs instead of the rotation speed ω of the engine 1. You may comprise. Also,
Even if each element function included in the integrated control function is composed of hardware electronic components, it is inevitably required to control analog power in addition to the normal engine-driven generator control function, as well as the detection function of the power section and sensors. Alternatively, digital processing may be performed using the same computer or individual computers, or only specific functions such as a recording function may be performed digitally. For example, arithmetic functions and set values set in advance for each function may be executed by software stored in a predetermined storage function. Therefore, if the integrated control function according to the present invention can be executed, the above-described power calculation function, torque calculation function, reactive power generation function, addition function and comparison function may be appropriately modified or divided. Of course, it may be integrated.

[0015]

According to the present invention, the above-described method is employed and the apparatus is constituted. Therefore, the engine-driven generator to which the present invention is applied has the following excellent effects. According to the present invention, the torque command value of the governor function of the engine is corrected in accordance with the change in the active power of the load, so that the frequency change can be prevented without delay in accordance with the load change. The reactive power generation function instantaneously absorbs the reactive power generated by the load, and generates a voltage that compensates for the voltage drop due to the internal impedance of the generator, which is mainly caused by the reactive power. The fluctuation is removed without delay in response to the fluctuation, and the voltage fluctuation corresponding to the load fluctuation is greatly reduced. As a result, frequency fluctuations and voltage fluctuations corresponding to load fluctuations are significantly reduced. When a phase-advancing capacitor is connected to the load circuit in parallel with the reactive power generation function, the reactive power can be controlled by increasing the rated capacity of the reactive power generation function. If the capacity of the phase advance capacitor is set equal to the rated capacity of the reactive power generation function, the controllable reactive power can be doubled. Since the phase-advancing capacitor can be less expensive than the reactive power generation function for the same absorbed reactive power value, the cost can be reduced. When the detected reactive power value at which the reactive power generation function functions according to the rated capacity of the phase advance capacitor is determined, the phase advance capacitor and the reactive power generation function can be effectively used. According to the present invention, since the fluctuation of the engine speed directly affects the generator frequency, the above-mentioned effect can be optimally exerted particularly for a synchronous generator having a large internal impedance.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram showing a basic configuration for explaining a first embodiment of an integrated control device to which an integrated control method for an engine-driven generator according to the present invention is applied.

FIG. 2 is a schematic configuration block diagram illustrating a basic configuration of a second embodiment of an integrated control device to which an integrated control method for an engine-driven generator according to the present invention is applied.

FIG. 3 is a schematic configuration block diagram showing a basic configuration of a conventional control device for an engine-driven generator.

[Explanation of symbols]

 1: Engine 1a: Rotational speed sensor 2: Generator (AC generator) 2a: Exciter 3: Load 4, 8: Comparison function (subtraction function) 5, 9: Servo amplification function 6: Fuel injection pump actuator 7: Fuel injection pump 10: Power amplification function 11: Instrument transformer 21: Instrument current transformer 22: Power calculation function 23: Load torque calculation function 24: Addition function 25: Reactive power generation function 26: Comparison function 27: Advance phase Capacitor ωs: rotation speed command value τs: torque command value P: detection active power value Q: detection reactive power value Qs: reactive power reference value Vs: voltage command value

Claims (6)

[Claims] In an engine-driven generator driven by an engine, a load torque of an engine corresponding to an active power of a load is calculated and added to a torque command value, and a reactive power of the load is connected to the load circuit. An integrated control method for an engine-driven generator, wherein the integrated power is absorbed by a power generation function. 2. A configuration in which a phase-advancing capacitor is connected to the load circuit, and a reactive power generation function functions for a reactive power of a predetermined value or more set in accordance with the rated capacity of the phase-advancing capacitor. The integrated control method for an engine-driven generator according to claim 1, wherein: 3. An engine-driven generator driven by an engine, comprising: a power calculation function for calculating active power and reactive power from an output voltage of the generator and a load current; A load torque calculation function for calculating torque, an addition function for adding a load torque calculated from the torque calculation function to a torque command value, and a reactive power for generating a reactive power corresponding to a reactive power value calculated from the power calculation function An engine-driven power generator having a generating function, wherein a load torque of the engine corresponding to the active power of the load is calculated and added to a torque command value, and the reactive power of the load is absorbed by the reactive power generating function. Machine integrated control device. 4. A phase-advancing capacitor is connected to a load circuit to which the reactive power generation function is connected, and a rated capacity of the reactive power generation function is set to a predetermined capacity corresponding to a rated capacity of the phase-advanced capacitor. The integrated control device for an engine-driven generator according to claim 3, wherein: 5. The integrated control device for an engine-driven generator according to claim 4, wherein the rated capacity of the reactive power generation function is set to be equal to the rated capacity of the phase advance capacitor. 6. A comparison function for comparing a predetermined value set in accordance with a rated capacity of the phase advance capacitor with a reactive power value calculated by a power calculation function, wherein a difference between the predetermined value and the reactive power value is provided. 6. The integrated control device for an engine-driven generator according to claim 4, wherein a reactive power generation function is made to function.