JPH02179300A - Variable-speed generator - Google Patents

Abstract

PURPOSE:To reduce the capacity of a controller by controlling the terminal voltage and frequency of an induction generator to predetermined values by the use of a regenerative inverter for regenerating the secondary power of the induction generator to the primary side of the induction generator. CONSTITUTION:A generator has a secondary current controller for full-wave rectifying the secondary current of an induction generator 1 and regulating the secondary current corresponding to the load of the induction generator 1 by the operation of a DC chopper 20 for short-circuiting to turn OFF the output side, and a controller 22 for controlling the terminal voltage and frequency of the induction generator 1 to predetermined values by a regenerative inverter 21 for regenerating the secondary power of the induction generator 1 to the primary side of the induction generator 1. Thus, the capacity of the regenerative inverter 21 is proportional to the secondary power, its capacity can be set to 1/several of the generated power, the element of the DC chopper 20 may be one to largely reduce the capacity of the controller.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a variable speed power generator.

[Conventional technology]

As shown in FIG. 5 of Japanese Unexamined Patent Publication No. 63-69499, a conventional variable speed power generator uses a first AC/DC converter 2 directly connected to the secondary winding of an induction generator 1 to generate a secondary current and Load adjustment is a method that controls the secondary frequency to keep the primary voltage and primary frequency of the induction generator 1 constant, and also controls the DC side voltage of the first and second AC/DC converters 2 and 3 to be constant. has been adopted.

The relationship between the voltage, current, and load on the secondary side of the induction generator 1 is based on the characteristics of the water turbine 4. At full load, the speed is zero, at no load, the speed is unrestricted, and at full load, the current value is maximum, and the voltage is zero,
When there is no load, the current is zero and the voltage is maximum.

Based on the above phenomenon, each of the six sets of control grooves in the first AC/DC converter 2 that converts DC voltage into three-phase voltage has a rated value that takes into account the maximum voltage value at no load and the maximum current value at full load. It is necessary to do so.

In the figure, 5 is a load, 6 is a primary current controller, 7 is a voltage setter, 8 is an adder, 9 is a voltage detector, 10 is a capacitor, 11 is a battery, 12 is an oscillator, and 13 is a secondary current control. 14 is a multiplier, 15 is an adder, 16 is a voltage detector, 17 is a voltage setting device, 18 is a rotational phase detector, 1
9 is a perfect phase detector.

[Problem to be solved by the invention]

The above conventional technology has a circuit configuration in which the rated current value and voltage value of the control element are all the maximum value, and the rated capacity must be selected larger than the actual value, which is difficult to rationalize the control device. There was a lack of consideration and there was a problem with the price.

The present invention has been made in view of the above points, and it is an object of the present invention to provide a variable speed power generation device that makes it possible to significantly reduce the capacity of the control section.

[Means to solve the problem]

The above purpose is to adjust the secondary current according to the load of the induction generator by operating a DC chopper that rectifies the secondary current of the induction generator and short-circuits its output side when turned on. and a control device that controls the terminal voltage and frequency of the induction generator to predetermined values using a regenerative inverter that regenerates the secondary power of the induction generator to the primary side of the induction generator. This is achieved by doing so.

[Effect]

Since the above means is provided, the current capacity of the regenerative inverter is 2
The capacity of the DC chopper is proportional to the power generated, and can be reduced to a fraction of the power generated, and the DC chopper requires only one element, making it possible to significantly reduce the capacity of the control section.

〔Example〕

The present invention will be explained below based on the illustrated embodiments. An embodiment of the present invention is shown in FIGS. 1-4.

Note that parts that are the same as those in the conventional system are given the same reference numerals, and therefore their explanations will be omitted. This is a variable speed power generation device equipped with a water turbine 4 and an induction generator 1. In this embodiment, the power generation device is a direct current that full-wave rectifies the secondary current of the induction generator 1 and short-terminates the output side by turning on the power generator. A secondary current control device that adjusts the secondary current according to the load of the induction generator 1 through the operation of the chopper 20, and a regenerative inverter 21 that regenerates the secondary power of the induction generator 1 to the primary side of the induction generator 1. It is configured to include a control device 22 that controls the terminal voltage and frequency of the induction generator 1 to predetermined values. By doing this, the capacity of the regenerative inverter 21 is proportional to the secondary power, and its capacity can be reduced to a fraction of the generated power, and the DC chopper 20 only needs one element, so that the control section The capacity can now be significantly reduced, and a variable speed power generator can be obtained that allows the capacity of the control section to be significantly reduced.

That is, the secondary current control device is connected to the load detector or load setting device (power detector or power setting device) P of the induction generator 1.
The secondary current of the induction generator 1 is adjusted in proportion to the value obtained by dividing the output value Po by the rotation speed N of the induction generator 1. Further, the secondary current of the induction generator 1 is limited according to the rotation speed of the water turbine 4. And this induction generator 1
The secondary current is controlled by controlling the DC chopper 20 so that the voltage on the DC side of the regenerative inverter 21 becomes a predetermined value. The output voltage of the regenerative inverter 21 is controlled according to the magnitude of the system voltage of the induction generator 1 and the command value of the system M voltage.

The induction generator 1 is configured to generate self-excited power by pressurizing the DC voltage of the regenerative inverter 21 with the battery 23.

That is, a load detector or load setting device (power detector or power setting device) connected to the voltage transformer PT and current transformer CT installed on the load side of the induction generator 1 by the secondary current control device. The secondary current value of the induction generator 1 is controlled in proportion to the value obtained by dividing the output value Po of P by the rotation speed N of the induction generator 1 via the calculator 24. At this time, the comparator 26 is operated using the deviation value between the secondary current command value corrected by the current limiting device 25 and the actual secondary current value so that the secondary current value is within the capacity of the regenerative inverter 21. , means for operating the DC chopper 20 and controlling the secondary current value to match the amount of power generation, and the means described below. That is, the terminal voltage of the capacitor 27 and the output of the voltage setting device 28 are detected by the voltage deviation detector 29, and this detected value and the current limiter 2
After adding the outputs of the DC chopper 20 and the output of the secondary current detector 31 in the comparator 26,
Creates an on/off signal for the DC chopper 20.
is operated to control the secondary current so that it is proportional to the output of the adder 30. Another method is to make the rated capacity of the regenerative inverter 21 a fraction of the rated capacity of the induction generator 1.

A capacitor 27 is installed in the DC side circuit of the regenerative inverter 21. In order to maintain the terminal voltage of the capacitor 27 at a constant value regardless of the rotation speed, the DC chopper 20 is operated according to the deviation value between the capacitor voltage setting value and the capacitor terminal voltage to maintain the constant value.

Furthermore, the output of a voltage regulator 35 that operates according to the deviation value between the primary voltage detector 33 of the induction generator 1 and the reference voltage setter (-blow mold pressure setter) 34 and the constant frequency from the reference frequency oscillator 36 The configuration is such that the output voltage of the regenerative inverter 21 is controlled in proportion to the value multiplied by the signal, and the primary voltage of the induction generator 1 is controlled via the first regenerative transformer 37.

Further, the DC voltage of the regenerative inverter 21 is pressurized by the power plant control battery 23 to operate the regenerative inverter 21, so that the induction generator 1 generates self-excited power.

By doing so, the power generation amount of the induction generator 1 can be controlled as follows. Output value P of load detector P
Current limit is corrected to a current limit value determined by a value that matches the torque curve of the water turbine 4 so that the value obtained by dividing G by the output value (rotation speed) N of the rotation detector 38 is within the capacity of the regenerative inverter 21. The output of the device 25 is applied via an adder 30 to a comparator 26, the output of which is amplified by a signal amplifier 32;
The DC chopper 20 is turned on and off to control the secondary current according to the load. At this time, if the load on the induction generator 1 decreases, the rotation speed increases, and if the load increases, the rotation speed decreases, but in either case, the DC chopper 20 is activated to perform load operation.

In order to make the terminal voltage on the DC side of the regenerative inverter 21 constant, the deviation signal between the terminal voltage of the capacitor 27 and the voltage setting device 28 is sent to the DC chopper 20 by the comparator 26 and the signal amplifier 32 via the adder 3o. On/off control
Since the secondary current is controlled according to fluctuations in the terminal voltage of the capacitor 27, a constant voltage can be maintained. That is, if the terminal voltage of the capacitor 27 is high, the secondary current is reduced, thereby lowering the terminal voltage of the capacitor 27.

Conversely, if the terminal voltage decreases, the secondary current increases, thereby increasing the terminal voltage of the capacitor 27.

Therefore, the voltage is controlled to be constant regardless of changes in rotation speed, load, etc.

Constant control of the terminal voltage and frequency of the induction generator 1 is as follows.
Based on the control device 22 of the regenerative inverter 21. That is, as shown in FIG. The output of the oscillator 39 is compared with the multiplication value of Frequency is controlled to be constant. This is because the output voltage of the regenerative inverter 21 is controlled according to the output of the voltage regulator 35.

It is maintained regardless of changes in rotation speed or load.

Self-excited power generation by the induction generator 1 is performed by pressurizing the DC voltage of the regenerative inverter 21 with the battery 23. When the DC side of the regenerative inverter 21 is pressurized by a generator control battery 23 or the like, the regenerative inverter 21 is activated and a constant frequency voltage is supplied to the primary winding of the induction generator 1. At this time, when the DC chopper 20 of the secondary current control DC circuit is turned on and off via the full-wave rectifier 42 connected to the secondary winding of the generator 1, a secondary current of the generator 1 is generated. The secondary power charges the capacitor 27 via a three-phase full-wave rectifier 42 and a reverse blocking diode 43. Since the terminal voltage of the capacitor 27 is thus maintained at a constant voltage, the regenerative inverter 21 can continue to operate without depending on the battery 23 from then on.

Since the secondary power generated when the DC chopper 20 is off charges the capacitor 27 via the reverse blocking diode 43, this DC current is regenerated to the primary side via the regenerative inverter 21. This regenerative power is determined by the secondary voltage and secondary current of the induction generator 1. −For example, take the rotation speed on the horizontal axis,
The vertical axis shows the rated current and voltage values of the induction generator as IP and U.
Figure 3 shows the relationship between the rotation speed and P and U when the bar unit is used as a bar unit.The secondary power is determined by the product of the secondary voltage and the secondary current, and the DC input current (DC Input current = secondary power / DC input voltage (constant value)) is proportional to secondary power, so the maximum capacity of a regenerative inverter is 1/4
and the capacity becomes small.

In addition, in Fig. 4, the horizontal axis represents the rotational speed, and the vertical axis represents the current command value determined from the torque characteristics of the water turbine, and the relationship between the current command value and the rotational speed is shown. The current command value is limited to below the straight line M shown in the figure.

As described above, according to this embodiment, the secondary power is converted by the full-wave rectifier, and the secondary current is controlled by turning it on and off using the DC chopper. The capacitor is charged with the secondary power generated at this time. The capacitor voltage at this time is controlled to be constant. The current in the DC circuit of the regenerative inverter is the value obtained by dividing the secondary power by the DC voltage. Therefore, the current capacity of the regenerative inverter is proportional to the secondary power, and its capacity can be reduced to a fraction of the generated power. Although the DC chopper applies the maximum capacity for both voltage and current, it is economical because only one element is required.

In other words, since the conventional first AC/DC converter is three-phase, it requires six sets of secondary current control elements (maximum rated capacity), but it only requires one set of DC choppers, so the regenerative inverter is 1/76 as described above. 4, a total capacity reduction effect of 58% can be obtained.

The secondary current control device calculates the secondary current value by dividing the load value by the rotation speed, and takes into account overload prevention of the regenerative inverter.
Since the current limiting device controls the DC chopper for adjusting the secondary current using the corrected value, the regenerative inverter does not exceed its rated capacity.

In order to reduce the capacity of the regenerative inverter, a capacitor is installed in the DC side circuit of the regenerative inverter, and the terminal voltage of the capacitor is controlled by a DC chopper to maintain a constant value regardless of the rotation speed, thereby reducing the capacity of the regenerative inverter. was realized.

Since the regenerative inverter was controlled by the deviation between the grid side voltage or the primary voltage of the induction generator and its set voltage and multiplication by the reference frequency oscillator output.

It was possible to maintain a constant value regardless of the load size or rotation speed.

Induction generators self-generate power by pressurizing the DC side of the regenerative inverter using a power plant control battery, etc., and operating the regenerative inverter to output a constant voltage and constant frequency to the primary winding of the induction generator via a regenerative transformer. Since we supplied the line,
I was able to make it happen.

As described above, according to the circuit configuration of the secondary current control device of the induction generator of this embodiment, a power generation device using a water wheel without a water flow rate adjustment mechanism can be used for a wide range of speed changes (rated 100% speed, S20, zero slip). (about 200%, 5=-1), the load can be adjusted from full load to no load using a constant voltage and a constant frequency.

〔Effect of the invention〕

As described above, the present invention makes it possible to significantly reduce the capacity of the control section, thereby providing a variable speed power generation device that allows the capacity of the control section to be significantly reduced.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a secondary side control unit of an embodiment of the variable speed power generator of the present invention, FIG. 2 is a block diagram of a control device of a regenerative inverter of an embodiment of the invention, and FIG. 3 is a block diagram of a control device of a regenerative inverter of an embodiment of the invention. Secondary voltage of an example induction generator. FIG. 4 is a characteristic diagram showing the relationship between secondary current and rotation speed, FIG. 4 is a characteristic diagram of a current limiting device according to one embodiment, and FIG. 5 is a block diagram of a conventional variable speed power generation device. DESCRIPTION OF SYMBOLS 1-... Induction generator, 4... Water turbine, 20... DC chopper, 21... Regeneration inverter, 22... Control device, 23... Battery, 42... Full-wave rectifier. 11--Bite raw >>/C-2

Claims (1)

[Scope of Claims] 1. In a variable speed power generation device comprising a prime mover and an induction generator, the device is a direct current chopper that rectifies the secondary current of the induction generator and short-circuits its output side when turned on. The induction generator includes a secondary current control device that adjusts the secondary current according to the load of the induction generator with the operation of 1. A variable speed power generator comprising: a control device for controlling the terminal voltage and frequency of the power generator to predetermined values. 2. The secondary current control device adjusts the secondary current of the induction generator according to a value obtained by dividing a value of a load detector or a load setter of the induction generator by the rotation speed of the induction generator. A variable speed power generation device according to claim 1, wherein the variable speed power generation device is constructed as follows. 3. The variable speed power generator according to claim 1, wherein the secondary current of the induction generator is limited according to the rotational speed of the prime mover. 4. The possibility according to claim 1, wherein the secondary current of the induction generator is controlled by controlling the DC chopper so that the voltage on the DC side of the regenerative inverter becomes a predetermined value. Variable speed generator. 5. The variable speed power generation device according to claim 1, wherein the output voltage of the regenerative inverter is controlled according to the magnitude of the grid voltage of the induction generator and the command value of the grid voltage. 6. The variable speed power generator according to claim 1, wherein the induction generator generates self-excited power by pressurizing the DC voltage of the regenerative inverter with a battery.