JPH04299100A - Output controller for stirling engine - Google Patents

Abstract

PURPOSE:To stabilize the rotational speed of engine without requiring a dummy load by providing a controller receiving a rotational speed signal of engine and an automatic voltage regulator which receives a signal from the controller and feeds an exciting current to an exciter interlocked with a generator. CONSTITUTION:A synchronous generator 5 is coupled with an exciter 4 which is coupled with a voltage regulator 2. The voltage regulator 2 provides the exciter 4 with an exciting current for varying the generating voltage of a generator 5 in response to a command signal fed from a controller 9. The controller 9 receives a signal corresponding to the rotational speed of engine from a rotation sensor 3. The controller 9 performs ON/OFF control of solenoid pressure reducing valve 7 and pressure intensifying valve 8 and regulates the average pressure in the working space of engine 6 thus regulating the engine output. When a load 10 decreases to cause relative increase of the rotational speed of engine, the controller 9 receives a signal from the rotational speed sensor 3 and delivers a command signal to the automatic voltage regulator 2 thus increasing current supply to the exciter 4.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an output control device for a system in which a generator is driven by a Stirling engine to obtain electric power and heat.

0002

2. Description of the Related Art Please refer to FIG. The working space of the Stirling engine 6 with a known configuration includes a helium gas cylinder 1.
1 through a pressure reducing valve 7 and a pressure increasing valve 8. When the pressure reducing valve 7 is opened, the maximum cycle pressure decreases and the output is reduced, but when the pressure increasing valve 8 is opened, the minimum cycle pressure increases and the output can be increased. The output of the Stirling engine 6 drives the synchronous generator 5 and supplies power to the load 10. 3 is a rotational speed sensor that monitors rotational speed fluctuations of the Stirling engine 6.

In the system shown in FIG. 2, when controlling the output, the pressure increasing valve 8 or the pressure reducing valve 7 is opened and closed to adjust the average pressure in the working space. This output adjustment method, however,
Poor responsiveness. For this reason, when there is a fluctuation in engine speed or load, the engine speed is not stabilized even if both valves 7 and 8 are controlled to open and close.

[0004] Therefore, a dummy load 1 is interposed between the generator 5 and the load 10. In this case, the output from the Stirling engine 6 is distributed between the load section 10 and the dummy load 1, and when engine speed or load fluctuations occur, the distribution ratio to the dummy load 1 is changed to accommodate this fluctuation. . Therefore, by setting the generated voltage of the generator, it is possible to keep the generated voltage constant even if the engine speed or load changes.

[0005]

The system shown in FIG. 2 uses a dummy load 1, but the power consumed by this dummy load 1 is of no use to the main load 10.

Therefore, the power generated by the generator is used as the main load without using a dummy load, and even if the engine speed or load changes, the speed to the engine is immediately stabilized. This is the problem to be solved by the present invention.

[0007]

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention uses means for increasing or decreasing the voltage generated by the generator within a certain range when there is a change in engine speed or load.

[0008] As a means for this, an exciter is linked to a generator, and an excitation current from an automatic voltage regulator is supplied to the exciter.
It is possible to instantly increase or decrease the generated voltage. The automatic voltage regulator changes the excitation current based on an instruction signal from a control device that receives a signal from an engine rotation sensor.

[0009] The control device also controls opening and closing of the pressure increase valve and the pressure reduction valve.

Specifically, the present invention provides an output control device for a Stirling engine that controls the supply of working gas to a working space using an increase/decrease valve, adjusts the average working gas pressure in the working space, and drives a generator with the output. An output control device for a Stirling engine, comprising a control device that inputs a rotation speed signal of the Stirling engine, and an automatic voltage regulator that receives a signal from the control device and supplies exciting current to an exciter that is interlocked with a generator. I will provide a.

[0011]

EXAMPLE Please refer to FIG. Components that are the same as those shown in FIG. 2 are denoted by the same reference numerals, and detailed description thereof will be omitted below.

An exciter 4 is connected to the synchronous generator 5, and a voltage regulator 2 is connected to the exciter 4. The voltage regulator 2 supplies an exciting current I to the exciter 4, which changes the voltage generated by the generator 5, in response to an instruction signal from the control device 9. The control device 9 receives a signal from the rotation sensor 3 according to the engine rotation speed.

The control device 9 controls the opening and closing of a pressure reducing valve 7 and a pressure increasing valve 8, which are electromagnetic valves, and adjusts the average pressure in the working space of the engine 6, thereby making it possible to adjust the engine output.

When the load 10 decreases and the engine speed relatively increases, or when the engine speed increases and the load 10 relatively increases, the control device 9 receives a signal from the rotation speed sensor 3. sends an instruction signal to the automatic voltage regulator 2 to increase the current to the exciter 4. This instantaneously increases the voltage generated by the generator 5, and applies a braking action to the generator 5 as a load.

At the same time, the pressure reducing valve 7 is opened by a signal from the control device 9 to lower the engine output. The variation in the rotational speed of the generator 5 is reduced by lowering the average pressure in the working space of the engine 6 and by applying a load braking action due to the voltage generated by the generator 5. This rotation speed is monitored by a sensor 3 and controlled by a controller 9.
input as a signal to

When the load 10 increases and the engine speed relatively decreases, or when the engine speed decreases and the load 10 relatively increases, control is performed in response to a signal from the rotation speed sensor 3. Device 9 sends an instruction signal to automatic voltage regulator 2 to reduce the current to exciter 4. this is,
The voltage generated by the generator 5 is instantly lowered, and the load braking action is released.

At the same time, the pressure increase valve 8 is opened by a signal from the control device 9 to increase the engine output. While monitoring the signal from the rotation speed sensor 3, the increase in the average pressure in the working space of the engine 6 and the release of the load braking action due to the voltage generated by the generator 5 reduce the fluctuation in the rotation speed of the generator 5.

The above-mentioned example is effective when the generated voltage is varied within a range of increasing up to 15% and decreasing up to 10%. When engine speed or load changes occur, such as increasing or decreasing the generated voltage within the range of 2-5%, power generation is performed only by the automatic voltage regulator 2 without controlling the opening and closing of the pressure increase valve 8 and pressure reduction valve 7. Fluctuations in the rotational speed of the machine 5 can be suppressed to a small level.

[0019]

According to the present invention, the output response of the generator to load fluctuations can be made extremely quick. In addition, since the output of the generator can be completely consumed by the load, the efficiency of the generator can be increased.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of an example of the present invention.

FIG. 2 is an explanatory diagram of a conventional example.

[Explanation of symbols]

2 Voltage regulator 3 Rotation speed sensor 4 Exciter 5. Synchronous generator 6 Stirling engine 7 Pressure reducing valve 8 Pressure increase valve 9 Controller 10 Load

Claims (2)

[Claims] Claim 1. An output control device for a Stirling engine that controls the supply of working gas to a working space using a pressure increase/decrease valve to adjust the average working gas pressure in the working space, and uses the output to drive a generator. An output control device for a Stirling engine, which includes a control device that inputs a signal, and an automatic voltage regulator that receives a signal from the control device and supplies an exciting current to an exciter that is interlocked with a generator. 2. The output control device according to claim 1, wherein the control device sends an opening/closing signal to the increase/decrease valve.