JPH0591798A - Power converter - Google Patents

Abstract

PURPOSE:To provide a power converter which controls the output power of turbine generators to fixed levels irrespective of the variation of their loads. CONSTITUTION:In order to control the output power of turbine generators 2 and 3 to fixed levels against the variation of the loads of the generators 2 and 3, a transistor 9 for switching and dummy load 10 are connected in parallel between the converter 4 and inverter 5 of a main circuit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power converter using the output of a turbine generator as a power source.

[0002]

2. Description of the Related Art FIG. 2 is a block diagram showing a conventional power converter of this type. In the figure, 1 is a tube, 2 is a turbine, 3 is a permanent magnet generator, 4 is a converter, 5 is an inverter, 6 is a load, 7 is a power supply (PS), and 8 is a controller.

Next, the operation will be described. A fluid such as water flows into the pipe body 1 to operate the turbine 2 and the permanent magnet type generator 3. The output voltage of the permanent magnet generator 3 is rectified by the converter 4 and the direct current voltage is frequency-converted by the inverter 5 to be applied to the load 6. Since the impedance of the load 6 varies greatly, the output current of the inverter 5 is made constant by detecting the load current and controlling the current with the controller 8. Further, the power supply 7 supplies a constant voltage power supply to the controller 8.

[0004]

Since the conventional power converter is constructed as described above, the rotation speeds N _r and N _{d are changed} with respect to the load impedance variation as shown in the turbine characteristic diagram of FIG. Difference ΔN, that is, the rotation fluctuation becomes large. Therefore, since the generator voltage fluctuates greatly, the power supply device becomes large, and there is a problem of mechanical life with the number of rotations. Therefore, as a method of keeping the output power of the turbine generator constant, a method of changing the flow rate of the pipe body 1,
Alternatively, there is a method of adjusting the angle of the blades of the turbine 2, but these solutions are impossible due to the structure.

The present invention has been made to solve the above problems, and provides a power converter capable of keeping the output power of a turbine generator constant with respect to a change in load impedance. It is an object.

[0006]

A power conversion device according to the present invention is a conventional power conversion device in which a switching transistor and a dummy load are inserted in parallel between a converter and an inverter of a main circuit.

[0007]

In the power converter according to the present invention, the controller controls the transistor according to the load to control the output power of the turbine generator by the dummy load.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1 in which the same parts as those in FIG. 2 are denoted by the same reference numerals, 9 is a transistor and 10 is a dummy load as a new configuration.

The power converter having the configuration shown in FIG. 1 detects the current of the load 6 and turns on and off the transistor 9 by the switching action of the controller 8 (at low load O
N), the dummy load 10 keeps the output power of the permanent magnet generator 3 constant. Therefore, the output power of the permanent magnet generator 3 can be made constant even if the load impedance fluctuates.

[0010]

As described above, according to the present invention, since the insertion of the dummy load is controlled according to the load, the generator constantly supplies a constant electric power, so that the rotational fluctuation is small. There is an effect to be obtained.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a power conversion device according to an embodiment of the present invention.

FIG. 2 is a configuration diagram showing a conventional power conversion device.

FIG. 3 is a turbine characteristic diagram of torque and rotation speed.

[Explanation of symbols]

 1 Tubular Body 2 Turbine 3 Permanent Magnet Generator 4 Converter 5 Inverter 6 Load 7 Power Supply (P.S) 8 Controller 9 Transistor 10 Dummy Load

Claims (1)

[Claims] 1. A turbine in a tubular body, a permanent magnet generator directly connected to the turbine, a converter for rectifying an output voltage from the generator, an inverter for frequency conversion, and the inverter according to a load. In a power conversion device including a controller for controlling, a switching transistor and a dummy load are added in parallel between the converter and the inverter, whereby the controller controls the transistor when the load changes. A power converter characterized in that the dummy load consumes the power of the generator.