JPH087065Y2 - Rotational speed controller for diesel generator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a rotation speed control device for a diesel generator.

(Prior Art) In a diesel generator, isochronous control is adopted in order to maintain the frequency of its output voltage at a desired value, and as a result, the rotational speed of the generator is controlled even when the load changes. It can be well maintained at the required value.
However, when the set rotational speed of the diesel generator is changed stepwise by changing the output frequency of the generator or switching from the idle operating state to the required rated operating state, in the past, fuel equivalent to a full rack was used. Since the engine was burned, there was a problem that black smoke was generated and the engine speed increased and an overshoot condition occurred.

In order to solve the problem that occurs when the set rotation speed is changed stepwise, Japanese Patent Laid-Open No. 53-44736 discloses a PI generator in response to the difference between the set rotation speed and the actual rotation speed of the generator.
In the configuration of performing D control, when the set rotation speed is changed stepwise, PID control is stopped until the actual rotation speed reaches a new set rotation speed, and control is performed to gradually increase the injection amount, A configuration is disclosed in which the PID control is resumed when the set rotational speed is reached.

(Problems to be Solved by the Invention) However, in this conventional technique, it is difficult to match the actual rotation speed with the set rotation speed in a short time without setting the full rack state. There is a problem that the time required for the transient control of 1 tends to be long.

An object of the present invention is to provide a rotation speed control device for a diesel generator that can solve the above-mentioned problems in the prior art.

(Means for Solving the Problems) A feature of the present invention for solving the above problems is that the fuel supply amount to the diesel engine is PID controlled in response to the difference between the set rotation speed and the actual rotation speed of the diesel generator. In order to do so, the diesel engine has a calculation means for performing a PID calculation based on the difference, and in response to an output from the calculation means, a diesel engine for controlling the fuel supply amount so as to maintain the rotation speed of the diesel generator at the set rotation speed. In the rotation speed control device of the generator, the detection means for detecting the amount of change in the actual rotation speed per unit time and the calculation means for the required period in response to the setting rotation speed being switched to a larger value are obtained. And a means for performing a correction for reducing the obtained output by an amount determined according to the output of the detecting means at that time.

(Operation) When the set rotation speed is set to a larger value, the difference between the set rotation speed and the actual rotation speed increases, and the fuel supply amount to the engine increases due to the PID control. As a result, the actual rotation speed rises rapidly, and a large output corresponding to the rapid rise is obtained from the detecting means. The output obtained by the calculation means is
Since it is reduced by an amount determined according to the output of the detection means, even if the set rotation speed is increased stepwise, the fuel supply amount increases with a moderate change amount that does not rapidly increase the actual rotation speed. Will be done. By properly setting the amount of decrease for correction according to the output of the detection means, the actual rotation speed can be made to match the required set rotation speed as quickly as possible without causing excessive supply of fuel. .

Embodiment An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a rotation speed control device for a diesel generator according to the present invention. In FIG. 1, 1 is a generator, 2 is a diesel engine for driving the generator 1, 3 is a fuel injection pump for injecting and supplying fuel to the diesel engine 2, and 4 is for adjusting a fuel supply amount. It is a fuel adjustment member. A rotation speed control device generally designated by the reference numeral 10 is a generator 1 or a diesel engine 2
Is a device for controlling the rotation speed of the control calculation unit 20 for calculating the target injection amount required to operate the diesel engine at the required set rotation speed, and the output signal S _a from the control calculation unit 20. And a servo control unit 50 for servo-controlling the position of the fuel adjusting member 4 to a required position corresponding to the position.

The servo control unit 50 responds to the output signal S _a by a converter 51 for converting into a target position signal S _b indicating the current target position of the fuel adjusting member 4 and an actual position indicating the current position of the fuel adjusting member 4. A position sensor 52 that outputs a signal P is provided. The servo circuit 53 outputs a control signal CS for controlling the actuator 54 for adjusting the position of the fuel adjusting member 4 in response to the target position signal S _b and the actual position signal P,
Servo control is performed so that the fuel adjustment member 4 is positioned at the target position indicated by the target position signal S _b .

Control calculation unit 20 includes a rotational speed detection unit 21 for outputting an actual velocity signal N ₁ indicating the actual detects the rotational speed N _a detection result of the diesel engine 2, the target rotational speed at that time of the diesel engine 2 N _t The target speed signal N ₂ indicating
22 and a target speed setting unit 24 that outputs in response to the operation of the second switch 23.

The first switch 22 connected to the power supply + V is a switch for designating whether the diesel engine 2 is in an idle operation state or a rated operation state. In the off state, the idle operation state is designated, and the on state thereof. You can specify the rated operating state with. The second switch 23 is the first
50 when the rated operating condition is specified by switch 22
It is a switch for designating whether the rated operation is Hz or 60 Hz. It is possible to designate 50 Hz in its off state and 60 Hz in its on state.

As can be seen from the above description, the first and second switches 22,2
Three operations, idle and 50Hz and 60Hz, can be specified by the operation of 3. The target speed setting unit 24 determines the output states of the first and second switches 22 and 23, and the target according to the specified state at that time. A target speed signal N ₂ indicating the rotation speed is output.

The actual speed signal N ₁ and the target speed signal N ₂ are input to the difference calculation unit 25, where the difference N _t −N _a is calculated, and the difference signal SS indicating the calculation result is output from the difference calculation unit 25. , PI
Input to the D calculation unit 26. The PID calculator 26 proportionally controls the fuel supply to the diesel engine 2 based on the difference.
The PID calculation unit 26 outputs a calculation output signal ES indicating the calculation result, which is a calculation unit for performing PID calculation for integration and differential control. As described below,
In the steady control state where the set rotation speed is not changed, the calculation output signal ES is taken out as the output signal S _a via the switch 27 and supplied to the servo control unit 50, and the fuel is supplied by the PID control according to the calculation output signal ES. The supply amount is controlled. As a result, the actual rotational speed N _a is the required target speed N _t
Held in.

When the set rotation speed is changed to a new set rotation speed by operating the first switch 22 or the second switch 23, the fuel adjusting member 4 does not cause excessive fuel supply as quickly as possible. In order to be positioned at a position corresponding to the new set rotation speed, the device of the present invention includes a differential operation unit 28 for obtaining the change amount of the actual rotation signal N ₁ per unit time, that is, the time differential value. The differential output signal BS obtained by time-differentiating the actual rotation signal N ₁ is
The multiplication unit 29 multiplies a predetermined constant to obtain a correction signal HS, which is input to the addition unit 30.

In this embodiment, the filter output signal FS obtained by removing the high frequency component of the operation output signal ES through the filter unit 31 is input to the adder unit 30, but the operation output signal ES is directly input as it is. You may. The filter output signal FS and the correction signal HS are added with the polarity shown in the addition section 30,
As a result, the filter output signal FS is corrected by the correction signal HS, and the corrected signal is the transient control signal for transient control.
It is output from the addition unit 30 as KS. The transient control signal KS is input to the switch 32, the switches 27 and 32 are switched and controlled by the switching control unit 40 described later, and the calculation output signal ES
Instead of this, the output from the switch 32 is supplied to the conversion unit 51 as the output signal S _a .

The switching control unit 40 includes a flip-flop circuit 41 that outputs a first signal C ₁ for performing switching control of the switch 27 and latch control of the latch unit 33 for latching the operation output signal ES, and the latch unit 33. Output and transient control signal KS
For controlling the switching of the switch 32 in response to the second
And a first comparing section 70 which outputs a signal C ₂ .

To obtain a set signal SS for setting the flip-flop circuit 41, a rating change detection unit 42 and a rated operation start detection unit 43 are provided. The rating change detection unit 42 responds to the first and second switches 22 and 23 and has a rating of 50 [Hz] to 60
It is detected that the frequency is changed to [Hz], and the output line when the second switch 23 is switched from off to on while the first switch 22 is on.
42a is switched from the low level state to the high level state. That is, in the rated operating condition, from 50 (Hz) to 60
When the rating is changed to [Hz], the level of the output line 42a is switched from "L" to "H", while 60
When the rating is changed from [Hz] to 50 [Hz], the level of the output line 42a is switched from "H" to "L". The rated operation start detector 43 responds to the first switch 22 and the key switch 34 to detect whether or not the engine is in the rated operation when the engine is started, and the switch 34 is turned on when the engine is started. When the rated operating state is selected by the first switch 22 at that time, the level of the output line 43a is switched from the low level state to the high level state.

The output lines 42a, 43a and the output line 22a of the first switch 22 are connected to the OR circuit 44, and the output from the output line 44a is taken out as the set signal SS and is output to the set input terminal S of the flip-flop circuit 41. Is being applied. Flip
Flop circuit 41 is set in response to the level of set signal SS changing from "L" to "H".

The second comparison unit 45 is a comparison circuit that responds to the actual speed signal N ₁ and the target speed signal N ₂ and sets the level of its output line 45a to a high level state when N _a = N _t . The output from the output line 45a is taken out as the reset signal RS,
It is input to the reset input terminal R of the flop circuit 41. The flip-flop circuit 41 is reset in response to the level of the reset signal RS changing from "L" to "H".

The first signal C ₁ from the Q output of the flip-flop circuit 41
Is a signal for controlling the switching of the switch 27.
When the level of the first signal C ₁ is “L”, the switch 27 is in the switching state shown by the solid line, and when the level of the first signal C ₁ is “H”, the switch 27 is in the dotted line. When the level of the first signal C ₁ changes from “L” to “H”, the latch unit 33 responds to this and latches the operation output signal ES. The first comparison unit 70 is
The value V _a of the transient control signal KS is compared with the value V _b of the operation output signal ES latched in the latch unit 33, and the level of the second signal C ₂ is “in response to the state of V _a <V _b ”. H ”and switch 32
Is in a switching state indicated by a dotted line.

Next, the operation of the rotation speed control device 10 shown in FIG. 1 will be described with reference to the waveform diagrams of FIGS. 2 (a) to 2 (g).

When the diesel generator shown in FIG. 1 is operating at the rated operation of 50 [Hz], the second switch 23 is turned on at the time t = t ₀ and changed to the rated operation state of 60 [Hz]. The operation in the case of being performed will be described as an example.

When the second switch 23 is turned on, the target speed signal N ₂ output from the target speed setting unit 24 has a content indicating a predetermined target rotation speed required to obtain an output voltage of 60 Hz. operation output signal ES according to the difference between the N _t and the actual rotational speed N _a is obtained. Immediately after switching the ratings, the difference is large, and as shown in FIG. 2C, the level of the operation output signal ES rapidly rises after t _{0 and} becomes substantially equal to the predetermined rated value level.

A change in rating at t = t ₀ is detected by the rating change detection unit 42, and the level of the output line 42a thereof changes from “L” to “H” at t = t ₀ . As a result, the flip-flop circuit 41 is set, the level of the first signal C ₁ changes from “L” to “H”, the level of the operation output signal ES at t = t ₀ is latched in the rat part 33, and switch
27 is switched to the state shown by the dotted line.

Further, since the actual rotational speed of the diesel engine 2 by rating as described above is changed rapidly increases as N _a is shown in FIG. 2 (b), the level of the correction signal HS and the second
As shown in FIG. 7E, the level rises at t = t ₀ , and the level decreases as the actual rotation speed approaches the target rotation speed and the increase rate of change decreases. On the other hand, the filter output signal FS is the operation output signal ES shown in FIG. 2 (c).
Is a signal extracted through the filter unit 31, and as shown in FIG. 2 (d), is a signal whose level changes more slowly than the operation output signal ES. Therefore, the transient control signal KS corresponding to the difference between the two signals FS and HS changes in level as shown in FIG. 2 (f). That is, immediately after t = t ₀ , the level is once greatly reduced, gradually increased, and approaches a required steady value.

The first comparing section 70, the level V _a is t = t ₀ of the transient control signal KS
And then outputs the second signal C ₂ which is in a low level state until t = t ₁ when V _a > V _b , where V _a > V _b .
When t <t ₁ , the switch 32 is in the switching state shown by the dotted line, and after t a = t ₁ , V _a = V _b , the switch 32 is in the switching state shown by the solid line. As a result, switch 32
As shown in FIG. 2 (g), the output level of t ₀ <
In the range of t <t ₁ , it becomes equal to the level of the operation output signal ES at t = t _0, and becomes equal to the level of the transient control signal KS at t ≧ t ₁ .

Therefore, after t = t ₀ , the fuel supply to the diesel engine 2 is controlled according to the output level of the switch 32 shown in FIG. 2 (g). As can be seen by comparing FIG. 2 (c) and FIG. 2 (g), the supplied fuel gradually increases after t = t ₁ after the rating is switched at t = t ₀ . Therefore, even if the target rotation speed changes stepwise, it is possible to prevent the temporary supply state of the fuel from being temporarily changed by the correction signal HS that gradually changes the target supply fuel as described above. The state of N _a = N _t can be realized as soon as possible. During this period, the control including the PID control element is performed, so that stable control is executed.

When N _a = N _{t at} t = t ₂ , the level of the output line 45a of the second comparing section 45 changes from “L” to “H”, and flipping occurs.
The flop circuit 41 is reset, and the switch 27 is switched from the state shown by the dotted line to the state shown by the solid line.
Therefore, when t> t ₂ , the operation output signal ES is again taken out as the output signal S _a , but when N _a = N _t , the level state of the operation output signal ES is the transient control signal KS.
The level change of the output signal S _a caused by this switching is extremely small.

Thus, in the transient state immediately after switching the rated performs correction for the target signal for the PID control according to the time differential value of the actual rotational speed N _a, without causing transient supply state of the fuel In addition, the fuel supply control for making N _a = N _t as quickly as possible is stably performed by the PID control.

In the above, the operation when the rating was changed from 50 (Hz) to 60 (Hz) was explained, but it is exactly the same when switching from idle operation to rated operation and when the engine enters the rated operation immediately after starting. In this way, the fuel supply control is performed, whereby the same effect as in the above case can be obtained.

Therefore, in the above-mentioned transient state, it is possible to obtain effects such as prevention of generation of black smoke, prevention of engine speed overshoot, and improvement of engine operation feeling.

In the above embodiment, when N _a = N _t , the switch 27 is returned to the state shown by the solid line. For example, instead of the flip-flop circuit 41, a monostable multivibrator is used, and the switch 27 is set to a predetermined value. When the state indicated by the dotted line is reached in response to the condition of, the state is kept for a predetermined time (>
Needless to say, it may be configured to hold t ₂ ).

(Effect of the Invention) According to the present invention, as described above, when the operation of changing the target value of the engine speed to a larger value is performed, the target control amount is corrected according to the degree of temporal change of the actual rotation speed. As a result, stable start control is performed so as to match the actual rotation speed to the target higher rotation speed as quickly as possible without causing a transient fuel supply state, and good improvement of transient control characteristics is achieved. Can be planned.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIGS. 2 (a) to 2 (b) are waveform diagrams showing signal waveforms of respective parts of the apparatus shown in FIG. 1 ... Generator, 2 ... Diesel engine, 10 ... Rotation speed control device, 24 ... Target speed setting unit, 25 ... Difference calculation unit,
26 …… PID calculator, 28 …… Differential calculator, 30 …… Adder, 2
7,32 ...... Switch, 40 ...... Switch control section, C ₁ ...... First signal, C ₂ ...... Second signal, S _a ...... Output signal, ES ...... Computation output signal, HS ...... Correction signal, SS: Differential signal.

Claims (1)

[Scope of utility model registration request] 1. In order to PID control the fuel supply amount to a diesel engine in response to a difference between a set rotational speed of a diesel generator and an actual rotational speed, there is provided an arithmetic means for performing a PID arithmetic operation based on the difference, In the rotational speed control device of the diesel generator for controlling the fuel supply amount so as to maintain the rotational speed of the diesel generator at the set rotational speed in response to the output from the computing means, the time of the actual rotational speed Detecting means for detecting a dynamic change rate, and an output obtained from the calculating means for a required period in response to the setting rotational speed being set to a larger value in accordance with the output of the detecting means at each time. A rotation speed control device for a diesel generator, comprising: a means for performing a correction for reducing a fixed amount.