JPS63117131A - Method and device for controlling speed of engine generator - Google Patents

Abstract

PURPOSE:To minimize the coefficient of instantaneous load fluctuation for simplifying the composition of a control device by computing control input taking a signal formed by adding a load differential signal to a speed deviation signal for a deviation signal, and then correcting the quantity of fuel supply on said control input. CONSTITUTION:A differentiator 5 differentiates the output of a load detector 4 to output a differential signal LD. A deviation signal generating circuit B is supplied with the output signal LD of said differentiator 5, the output signal NO of a speed setting equipment 6 and the output signal N of a speed detector 7 as its input to issue the deviation signal. PID computing circuit 9 is supplied with said deviation signal as its input to compute control input. A fuel injection pump 11 supplys fuel to a diesel engine 2. Thus the coefficient of instantaneous load fluctuation can be minimized to simplify the composition of a control device.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a speed control method for controlling the output of a motor generator driven by an internal combustion engine, and a speed control device for implementing this method.

[Prior Art] In a motor generator driven by an internal combustion engine such as diesel 1rsa, the rotational speed is controlled to be constant in order to keep the output frequency constant, and in this case, the instantaneous load fluctuation rate and It is necessary to keep the settling fluctuation rate as small as possible.

In a conventional control device that controls a motor generator driven by an internal combustion engine, a position sensor and an actuator are installed in a control rack that adjusts the injection amount of a fuel injection pump, as shown in Japanese Utility Model Publication No. 58-7072, for example. Connect and issue? ! The settling fluctuation rate is made zero by calculating the operation amount of the actuator based on the integral output of the deviation between the detection signal of the rotational speed of the machine and the speed setting signal. In addition, in this type of conventional control device, the load of the lithium generator is 1! The position of the control rack calculated based on the flow detection signal is set as the target position, and by controlling the actuator so that the control rack position detection signal matches the signal indicating the target position, the load fluctuation is reduced to the rotation of the internal combustion engine. The amount of fuel supplied to the internal combustion engine is corrected to reduce the instantaneous load fluctuation rate before it appears as a speed fluctuation.

[Problems to be Solved by the Invention] According to the conventional control device described above, it is possible to reduce the settling fluctuation rate to zero and to reduce the instantaneous load fluctuation rate, but it is difficult to supply fuel to the internal combustion engine. It was necessary to attach a position sensor to the fuel supply amount adjusting means (in the above example, the control rack of the fuel injection pump) that adjusts the amount. As a result, the structure of the device becomes complicated, and there are problems in that it cannot be easily applied to existing motor generators that do not have a control device.

SUMMARY OF THE INVENTION An object of the present invention is to provide a speed control method for a motor generator that can reduce the instantaneous load fluctuation rate without using a position sensor for detecting the position of a fuel supply ffi adjustment means, and an apparatus for implementing the method. Our goal is to provide the following.

[Means for Solving the Problems] The invention of cylinder 1 of the present application is based on an engine 'I1 driven by an internal combustion engine.
The operation m of the actuator that adjusts the amount of fuel supplied to the internal combustion engine is calculated based on the deviation between the rotational speed of the engine and the set speed, and the amount of fuel supplied to the internal combustion engine is adjusted.
In a speed control method for a motor generator that controls the rotational speed of an engine to maintain it at a set speed, without using a position sensor that detects the position of a fuel supply amount adjusting means that adjusts the amount of fuel supplied to an internal combustion engine. It is possible to perform predictive control during load fluctuations to reduce the instantaneous load fluctuation rate.

Therefore, in the method of the present invention, the load differential signal is obtained by differentiating the generator load detection signal when the load changes, and the load differential signal is obtained before the generator load change appears as a change in the rotational speed of the internal combustion engine. The fuel supply m to the internal combustion engine is corrected by calculating the fuel supply amount using the signal as a deviation.

The invention of cylinder 2 of the present application is a speed control device used for carrying out the method of the first invention.

In general, a speed control device for a motor starter includes a speed detector that detects the rotational speed of a generator driven by an internal combustion engine, and a speed setter that outputs a speed setting signal that indicates the set speed of the generator. , a deviation signal generation circuit that outputs a deviation signal containing information on speed deviation obtained from the speed detection signal and the speed setting signal, and operation of an actuator that uses the deviation signal as input to adjust the supply of fuel to the internal combustion engine. A calculation circuit for calculating the amount is provided, and the rotational speed of the generator is controlled to be maintained at a set speed by operating the actuator according to the operation amount calculated by the calculation circuit.

The invention of the present application cylinder 2 makes it possible to suppress the instantaneous load fluctuation rate to a small value by performing predictive control at the time of load fluctuation without attaching a position sensor to the fuel supply amount adjusting means in the speed control device as described above. It is something.

Therefore, in the present invention, a load detector that detects the load current and outputs a load detection signal, and a differentiator that differentiates the load detection signal and outputs a load differential signal are provided. A signal obtained by adding a load differential signal to a deviation signal is output as the deviation signal.

[Operation of the Invention] When a signal obtained by adding a load differential signal to a speed deviation is used as a deviation signal as described above, when a load fluctuation occurs, the load fluctuation appears as a fluctuation in the rotational speed of the generator. The previous state! II (state in which the rotational speed of the generator matches the set rotational speed), the load differential signal is given to the calculation circuit as a deviation signal, so the deviation signal determines the fuel supply ffi.
By calculating the operation amount of the adjusting means, the internal combustion I! ! The amount of fuel supplied to the II can be adjusted in advance, thereby making it possible to reduce the instantaneous load fluctuation rate.

That is, when the load increases, the load differential signal is given to the arithmetic circuit as a deviation signal before the increase in load appears as a decrease in the rotational speed of the generator, so the arithmetic circuit increases the fuel supply m. Calculate the manipulated variable so that
Thereby, the fuel supply amount adjusting means is controlled to increase the amount of fuel supplied to the internal combustion engine, thereby suppressing a decrease in the rotational speed of the generator. Furthermore, when the load decreases, the load differential signal is given to the arithmetic circuit as a deviation signal before the decrease in load appears as an increase in the rotational speed of the generator.
The arithmetic circuit calculates the manipulated variable to decrease the amount of fuel supplied, and thereby decreases the amount of fuel supplied to the internal combustion engine by reducing the amount of fuel supplied to 1! Jlf) means to suppress an increase in the rotational speed of the generator.

[Example] The present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention, in which 1 is a generator, 2 is a diesel engine that drives the generator 1, and 3 is a load connected between the output terminals of the generator 1. It is. 4 is a load detector which inputs the output of the current transformer CT which detects the load current supplied from the power generation n1 to the load 3, and outputs a DC load detection signal having a level corresponding to the load current; 5 is the load This is a differentiator that differentiates the output of the detector 4 and outputs a differential signal LD of the load detection signal.

6 is a speed setting device that outputs a speed setting signal NO giving the set rotational speed of the generator, and 7 is a rotation sensor 7a and a frequency-voltage converter (F/V converter>7b), which detects the actual rotational speed of the generator. A speed detector 8 outputs a speed detection signal N indicating the rotational speed of the internal combustion engine (same as the rotational speed of the internal combustion engine); 8 is the output signal LD of the differentiator 5, the output signal NO of the speed setter 6, and the output signal N of the speed detector 7. and the deviation signal (No-N) as input.
+LD, the deviation signal generating circuit 8 includes an adder 8a that adds the differential signal LO and the speed setting signal No, and generates the speed detection signal N from the output of the adder 8a.
and a subtracter that subtracts the . 9 is a PID calculation circuit that calculates the manipulated variable for maintaining the rotational speed of the generator at a set rotational speed by performing proportional, integral, and differential calculations using the deviation signal as input; 10 inputs the output from calculation circuit 9; 11 is a fuel injection pump that supplies fuel to the diesel engine 2; 12 is a fuel injection pump that controls the injection amount of the fuel injection pump 11 according to the operation signal given from the operation signal output circuit 10; This is an actuator that operates the control rack (fuel supply amount adjustment means) to be adjusted, and includes a load detector 4, a differentiator 5, a speed setting device 6, a speed detector 7, a deviation signal generator 8, an arithmetic circuit 9, and an operation signal output. The circuit 10 constitutes a control device 13 of the present invention.

The load detector 4 includes a resistor 4, for example, as shown in FIG.
1, an adjustment FE device 42, a detection start level setting device 43,
It is composed of a timing circuit 44, a peak hold circuit 45, a sample hold circuit 46, and a limiter circuit 47. That is, a resistor 41 is connected to the output terminal of the current transformer CT.
is connected, and a voltage proportional to the load current I obtained across the resistor is input to the full-wave rectifier 42. The timing circuit 44 inputs the output of the rectifier 42 and the output LO of the detection start level setter 43, and when the output voltage of the rectifier 42 is equal to or higher than level 8 of the output signal LO of the detection start level setter 43, the timing circuit 44 outputs the sample and hold signal Sh and peaks. A hold reset signal P is sequentially generated with a predetermined phase difference.A peak hold circuit 45 holds the peak value of the output voltage of the rectifier 42, and generates a peak hold reset signal M.
It is reset when Pr is given. The sample hold circuit 46 receives the output of the peak hold circuit 45 and the sample hold signal sh, samples and holds the output of the peak hold circuit every time the sample hold signal 3h is generated, and sends the output 1s to the limiter circuit 4.
Give to 7. The limiter circuit 47 outputs a DC signal at level A as a load detection signal when the output S of the sample and hold circuit 46 is below the level A (detection start level) of the output signal LO of the detection start level setter 43, When the output signal S of the sample and hold circuit 46 exceeds the lower limit level 8, a DC signal equal to the level of the output signal LS of the sample and hold circuit 46 is outputted as a load detection signal.

An example of the signal waveform of each part of the load detection circuit in Fig. 3 is shown in Fig. 4. Fig. 4 (a) shows the waveform of the load current ■ detected by the current transformer CT, and Fig. ) shows the output waveform of the rectifier 42. In FIG. 4(b), the level A is the output level O of the detection start level setting circuit 43, and the timing circuit 44 first sets the level A after a certain period of time from the time when the output voltage of the rectifier 42 becomes equal to or higher than the detection start level A. As shown in FIG. 4(C), a sample hold signal Sh is output, and then a peak hold reset signal @Pr is output as shown in FIG. 4(d). The peak hold circuit 45 inputs the output voltage of the rectifier 42, and when the voltage reaches a peak, holds the peak value as shown in FIG. 4(e),
It is reset when reset pr is given. The sample hold circuit 46 holds the output of the peak hold circuit 45 every time a sample hold signal is applied, and
A signal 1s as shown in Figure (f) is output.

The limiter circuit 47 inputs this signal LS, applies a lower limit to it, and outputs a load detection signal with a detection start level of 8 or higher. The relationship between the load detection signal output from the limiter circuit 47 and the load current is as shown in FIG. As in this embodiment, the lower limit level A of the load detection signal
The reason for providing this is that the load detection signal is equal to the load current I in Fig. 5.
The purpose is to prevent step-like changes with the boundary at 0.

Next, the operation of the above embodiment will be explained with reference to FIG. In FIG. 1, a load detector 4 detects a load current I and outputs a load detection signal. The rotation sensor 7a of the speed detector 7 is attached to the output shaft of the diesel engine 2 or a shaft that rotates synchronously with the output shaft, and outputs a pulse signal with a frequency proportional to the rotation speed of the engine. The F/V converter 7b outputs a voltage proportional to the frequency of this signal as the speed detection signal N.

The load detection signal S is input to a differentiator 5 and differentiated. The polarity of the differential signal LD output by the differentiator 5 is such that the polarity of the differential signal when the load detection signal increases is the same as the polarity of the speed setting signal NO (positive polarity in this embodiment). When the load detection signal decreases, the polarity of the differential signal becomes opposite to the polarity of the speed setting signal (negative polarity in this embodiment). The differential signal LD is inputted together with the speed setting signal NO to the addition circuit 8a of the deviation signal generation circuit 8 and both signals are added together, and the output No+LD of the addition circuit 8a is inputted together with the speed detection signal N to the subtraction circuit 8b to perform the subtraction. A deviation signal (No-N)+LD is output from the circuit 8b. This deviation signal is a signal obtained by adding the differential signal LD of the load detection signal to the deviation (No-N) between the set speed and the actual rotational speed.

The differential signal LD is generated only when load fluctuation occurs,
In a steady state where the load remains constant, the differential signal LD is zero. At this time, the deviation signal becomes (NO-N), and the calculation circuit 9 calculates the operation amount for making the rotational speed N of the generator match the set speed No, and provides it to the operation signal output circuit 10. The operation signal output circuit 10 gives an operation signal to the actuator 12, displaces the actuator 12 in a predetermined direction, operates the control rack of the fuel injection pump 11, adjusts the amount of fuel supplied to the engine, and rotates the generator. Change the speed to match the set speed. When the rotational speed of the generator matches the set speed, the deviation (No-N> becomes zero, so the operation amount calculated by the calculation circuit 9 becomes zero, the actuator stops, and the rotational speed of the generator is maintained.

On the other hand, the operation when the generator load fluctuates is as follows. The waveform of the load current ■ of the electric machine is shown in Figure 2 (b).
Assuming that the output signal of the load detector 4 is as shown in FIG. 2(b), the differentiator 5 has a waveform as shown in FIG.
As shown in C), a pulsed differential signal LD is output at each rise and fall of this load detection signal. When the load increases, the rotational speed of the internal combustion engine does not decrease immediately and the initial deviation (No-N) remains zero, but at this time a differential signal LD with the same polarity as the speed setting signal NO is generated. , this differential signal LD is given as a positive deviation signal to the arithmetic circuit 9, and the arithmetic circuit 9 outputs a manipulated variable for increasing the amount of fuel supplied to the internal combustion engine. As a result, the actuator 12 moves the rack of the fuel injection pump 11 to the side where the fuel supply amount increases, and the internal combustion ir! Suppresses the decrease in rotational speed of I. At this time, the output of the arithmetic circuit 9 and the output signal N of the speed detector 7 are as shown in FIG. 2(d) and (e), respectively.
The fluctuation rate of rotational speed (instantaneous load fluctuation rate) when the load fluctuates can be kept low. When the rotational speed of the rearward mi gate decreases due to an increase in load, a speed deviation (No-N) appears (at this time, the differential signal LO has already become zero), so the speed is controlled by the above-mentioned operation. will be held.

When the load decreases, a differential signal LD with a polarity opposite to that of the speed setting signal NO is generated, so the calculation circuit 9 calculates the amount of operation to decrease the fuel supply to the internal combustion engine, and increases the amount of fuel to the engine. The increase in rotational speed is suppressed by reducing the number of fuel suppliers.

Figures 2 (d') and (e') respectively show the output of the arithmetic circuit 9 and the output signal N of the speed detector 7 in a conventional control device that does not use the load differential signal as the deviation signal. When the rotation speed fluctuates greatly. According to the present invention, speed fluctuations based on such load fluctuations can be suppressed.

FIG. 6 shows another embodiment of the invention. In this embodiment, the deviation signal generating circuit 8 consists of a subtracter f3a- and a subtracter 8b, and the subtracter 8a- subtracts the differentiator @LD from the speed detection signal N to obtain the signal @<N-Ll)). Output. The subtracter 8b inputs the output of the subtracter 3a- and the speed setting signal NO, and converts the speed deviation (No-N) into a differential signal L.
[Outputs a deviation signal with the addition of l. Other points are similar to the embodiment shown in FIG.

In the above example, a case where a diesel engine is used to drive a Ti-producing rock is taken as an example, but the present invention can be similarly applied to a case where a gasoline engine is used to drive a generator.

Further, in the above example, a fuel injection pump is used as a means for supplying fuel to the payload, and the control rack of the fuel injection pump is operated by an actuator, but in the present invention, the configuration of the fuel supply means is arbitrary. Even when a carburetor is used, the present invention can be applied by attaching a 7-cut unit to the throttle valve.

In the embodiments shown in FIGS. 1 and 6, the speed detector is installed on the internal combustion engine side.
Of course, it is also possible to attach it to the generator side.

[Effects of the Invention] As described above, according to the present invention, a signal obtained by adding a load differential signal to a speed deviation signal is used as a deviation signal to calculate the manipulated variable, so when a load fluctuation occurs, the speed Internal combustion IIg! uses the differential signal of the load detection signal as a deviation signal before fluctuations occur! The amount of fuel supplied to 1 can be modified,
The instantaneous load fluctuation rate can be kept small. According to the present invention, there is no need to provide a sensor for detecting the position of the fuel supply node means for adjusting the amount of fuel supplied to the internal combustion engine, so the configuration of the control device can be simplified, and the existing It can also be easily applied to power generators.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the control device of the present invention;
Figure 2 is a signal waveform diagram of each part in Figure 1, Figure 3 is a block diagram showing an example of the configuration of the load detector used in the embodiment of Figure 1, and Figure 4 is a signal waveform diagram of each part in Figure 3. 5 is a diagram showing the relationship between the load detection signal obtained by the load detector of FIG. 3 and the load current, and FIG. 6 is a block diagram showing another embodiment of the control device of the present invention. . 1... Generator, 2... Diesel engine, 3... Load, 4... Load detector, 5... Differentiator, 6... Speed setter, 7... Speed detector , 8... Deviation signal generation circuit, 9... P10 calculation circuit, 10... Operation signal output circuit, 11... Fuel injection pump, 12... Actuator. Fig. 1 Fig. 2 Fig. Ce／＞Cow” Fig. 4 Fig. 5 Fig. 6

Claims (2)

[Claims] (1) Adjust the amount of fuel supplied to the internal combustion engine by calculating the operation amount of the actuator that adjusts the amount of fuel supplied to the internal combustion engine from the deviation between the rotational speed of the generator driven by the internal combustion engine and the set speed. In the speed control method of a motor generator, the speed control method of a motor generator is performed by differentiating a detection signal of a load of the generator to obtain a load differential signal when the load fluctuates, and controlling the rotation speed of the generator to a set speed. The amount of fuel supplied to the internal combustion engine is corrected by calculating the amount of fuel supplied using the load differential signal as a deviation before a variation in the load of the engine appears as a variation in the rotational speed of the internal combustion engine. How to control the speed of a motor generator. (2) a speed detector that detects the rotational speed of a generator driven by an internal combustion engine; a speed setter that outputs a speed setting signal that instructs the set speed of the generator; and the speed detection signal and the speed setting signal. a deviation signal generation circuit that outputs a deviation signal including speed deviation information obtained from the above, and an arithmetic circuit that uses the deviation signal as input to calculate an operation amount of an actuator that adjusts the amount of fuel supplied to the internal combustion engine. In a speed control device for a motor generator that controls the rotation speed of the generator to be maintained at a set speed by operating the actuator according to the operation amount, the speed control device detects a load current and outputs a load detection signal. and a differentiator that differentiates the load detection signal and outputs a load differential signal, and the deviation signal generation circuit generates a signal obtained by adding the load differential signal to the speed deviation signal as the deviation. A speed control device for a motor generator, characterized in that it is configured to output as a signal.