JP2578200B2 - Voltage control device of power generator - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a voltage control device of a power generator,
The present invention relates to a voltage control device that makes an output voltage of an induction generator constant in order to achieve a constant voltage of an intermediate DC voltage of a stationary frequency converter with respect to a power generator having an induction generator and a static frequency converter. .

(Prior Art) FIG. 5 shows a conventional power generator having an induction generator and a stationary frequency converter. That is, in the figure, reference numeral 1 denotes a prime mover serving as an energy generation source, and 2 denotes a prime mover 1
, 3 is a capacitor for exciting the induction generator 2, 4 is a stationary frequency converter for converting the output power of the induction generator 2 into AC power of a commercial frequency and taking out the same. Is a power system. Here, the frequency conversion device 4 includes a converter 41 including a gate-controllable semiconductor switching element such as a thyristor, an inverter 43, a smoothing reactor 42, and a constant voltage control device 44.
The intermediate direct current voltage V _d of the frequency converter 4 to constant voltage, it has been necessary to control the constant voltage control unit 44 sends a gate pulse GP respect converter 41.

In addition to this, as a method of converting the intermediate DC voltage _Vd to a constant voltage, a saturable reactor 6 having characteristics suitable for the voltage fluctuation characteristics of the induction generator 2 in an output circuit of the induction generator 2 as shown in FIG. And the amount of voltage fluctuation of the induction generator 2 accompanying the fluctuation of the output power of the power generator is caused to flow into the saturable reactor 6 to keep the output voltage of the induction generator 2 at a constant value. The intermediate DC voltage _Vd was made constant.

In the frequency converter 4 'shown in FIG.
1 'is a converter composed of a diode rectifier.

(Problems to be Solved) However, in the method of constant voltage to the gate controls the converter 41 as shown in Figure 5, to the intermediate DC voltage V _d of the static converter 4 to a constant value Requires a dedicated constant voltage control device 44, which increases the cost. In addition, since the output voltage of the induction generator 2 fluctuates with the fluctuation of the output power of the power generator, the disadvantage that the reverse withstand voltage of the semiconductor switching element constituting the converter 41 is also large is uneconomical. there were.

Further, in the system employing the saturable reactor 6 as shown in FIG. 6, the output power-output voltage characteristic of the induction generator 2 and the saturable reactor
The have difficulty in matching with the saturation characteristic as a result of the constant voltage of the output voltage of the induction generator 2 is not necessarily achieved, can not be kept intermediate DC voltage V _d of the frequency converter 4 'to a constant value, There is a risk that the inverter 43 of the frequency converter 4 'may fail to commutate.

The present invention has been proposed in order to solve the above-mentioned problems. The purpose of the present invention is to economically convert an intermediate DC voltage to a constant voltage without using a dedicated control device or a power device such as a saturable reactor. It is another object of the present invention to provide a voltage control device of a power generation device that enables stable inverter control.

(Means for Solving the Problems) In order to achieve the above object, according to the present invention, a main control method in a control device of a power generator is based on a rotation speed control device that keeps a rotation speed of a prime mover at a predetermined value. As will be described later, the output voltage of the induction generator is focused on being proportional to the rotation speed.

That is, the present invention is a power generator including an induction generator coupled to a prime mover, and a stationary frequency converter for converting output power of the induction generator into AC power having a predetermined frequency and extracting the AC power. A power generator including a rotation speed control device that keeps the rotation speed of the prime mover at a predetermined value by increasing or decreasing output power of the induction generator taken out through the stationary frequency conversion device, wherein the output of the power generation device is A function generator to which power is input, and an actual rotation speed set value such that the output voltage of the induction generator becomes a constant value based on the output of the function generation unit and the rotation speed set value of the prime mover, Actual rotation speed setting means for outputting the actual rotation speed setting value as a setting value to be compared with the rotation speed detection value in the rotation speed control device.

(Operation) According to the present invention, when an arbitrary output voltage of the power generator is generated, a value obtained by subtracting the output of the function generator corresponding to the voltage fluctuation compensation of the induction generator from the predetermined rotation speed set value of the prime mover. Is the actual rotational speed set value of the prime mover. This allows
The actual rotational speed of the prime mover will change from the original rotational speed set value by the amount equivalent to the voltage fluctuation compensation, and the output voltage of the induction generator and the intermediate DC voltage of the stationary frequency converter can be made constant. it can.

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

FIG. 1 shows a voltage control device according to this embodiment together with a power generation device. The power generation device is composed of a prime mover 1, an induction generator 2, a capacitor 3, and a static type frequency converter 4 'as in the prior art. Has become. The voltage control device according to the present invention increases or decreases the output power of the induction generator 2 taken out via the frequency conversion device 4 ′, thereby
The normal rotation speed control device 7 for keeping the rotation speed of the
It is configured such that a voltage fluctuation compensation circuit 8 is added.

The rotation speed control device 7, a rotational speed detector 71 for detecting the rotational speed of the prime mover 1, the actual rotation speed setting which is the output of the subtractor 81 to be described later and the rotational speed detection value n _d by the detector 71 value
Rotational speed controller that performs adjustment operation to make the deviation from n _s ' zero
72, and a firing angle phase adjuster 73 that outputs a gate pulse GP to the inverter 43 of the frequency conversion device 4 'based on the output of the rotation speed adjuster 72.

On the other hand, the voltage fluctuation compensating circuit 8 includes a DC current detector 83 for detecting the intermediate DC current of the frequency converter 4 ', a function generator 82 to which the output of the detector 83 is added, and an output of the function generator 82 for setting the rotation speed. 'and subtractor 81 as a real rotational speed setting means for generating, the actual rotational speed setting value n _s' is subtracted from n _s new actual rotational speed setting value n _s a deviation between the rotational speed detection value n _d and The desired comparator
It consists of 84.

Next, this operation will be described with reference to FIGS.

First, FIG. 2 shows an output power (P) -power voltage (V) characteristic of the induction generator 2 (a characteristic line is indicated by a). In the induction generator 2, the output voltage increases as the generated output power decreases. Become. The output voltage V _n in the figure is the rated output power P _n
Indicates the voltage at the time of occurrence. FIG. 3 shows the rotation speed (n) -output voltage (V) characteristics of the induction generator 2.
In the output voltage is substantially proportional to the rotational speed in the following speed near rated speed n _n. The output voltage V _n 'in the drawing shows the voltage at the rated rotational speed n _n.

Now, in FIG. 4, it is assumed that the target output voltage of the induction generator 2 is a rated value represented by b in the figure. The characteristic line a is the same as that shown in FIG. Here, the characteristic line c in FIG. 4 is a voltage difference between the characteristic lines a and b,
The relationship between the output power of the induction generator 2 for compensating for the difference voltage, the output voltage, and the rotation speed change Δn is shown.

That is, in this embodiment, the intermediate DC current of the frequency conversion device 4 'is detected by the DC current
Detecting as a substitute for P _d, setting the output characteristics of the function generator 83 which receives the output power P _d as in the fourth diagram of characteristic lines c. Then, the output of the function generator 82 is subtracted from the original rotational speed set value n _s by the subtractor 81, and the result is input to the comparator 84 as a new actual rotational speed set value n _s '.

As a result, at the point where the output power of the power generator is zero, the value obtained by subtracting the value Δn corresponding to the voltage fluctuation compensation from the function generator 82 from the set value n _s to keep the rotation speed at a predetermined value becomes the rotation speed. The actual rotational speed becomes the actual rotational speed set value n _s ′, and the actual rotational speed falls below the original rotational speed set value n _s by the value Δn corresponding to the voltage fluctuation compensation. As described above, the rotation speed set value and the actual rotation speed are reduced by the amount corresponding to the voltage fluctuation compensation, so that the output voltage of the induction generator 2 can be maintained at the target constant voltage.

In this embodiment, even when an arbitrary output power other than zero is generated, the value Δn corresponding to the voltage fluctuation compensation at the time of the arbitrary output power generation shown by the characteristic line c in FIG. The induction generator 2 as described above.
Can be maintained at a target voltage, whereby the intermediate DC voltage of the frequency converter 4 'can be made constant.

(Effects of the Invention) As described above, according to the present invention, a dedicated control device or a power device such as a saturable reactor is not required to make the intermediate DC voltage of the stationary frequency converter constant, and a normal This is very economical because it can be realized by a simple circuit in which a voltage fluctuation compensation circuit having a simple configuration is added to the rotation speed control device.

Further, there is no fear of inverter commutation failure occurring when a saturable reactor or the like is used, and stable inverter control of the stationary frequency converter can be performed, and at the same time an inexpensive energy-saving power generation system can be provided. .

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention together with a power generator, FIG. 2 is an output power-output voltage characteristic diagram of an induction generator,
FIG. 3 is a graph showing the relationship between the rotation speed and the output voltage, FIG. 4 is a graph showing the relationship between the output power and the output voltage and the change in the rotation speed to compensate for the voltage fluctuation, and FIGS. FIG. 2 is a configuration diagram illustrating a constant voltage control method. DESCRIPTION OF SYMBOLS 1 ... Motor 2 ... Induction generator 3 ... Capacitor 4 '... Static frequency converter 5 ... Power system 7 ... Rotation speed controller 8 ... Voltage fluctuation compensation circuit 41' ... Converter , 42 ... Smoothing reactor 43 ... Inverter, 71 ... Rotation speed detector 72 ... Rotation speed regulator, 73 ... Ignition angle phase adjuster 81 ... Subtractor, 82 ... Function generator 83 ... DC current detector, 84 …… Comparator

 ────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-57-3117 (JP, A) JP-A-62-123997 (JP, A) JP-A-63-265597 (JP, A)

Claims (1)

(57) [Claims] A power generator comprising: an induction generator coupled to a prime mover; and a stationary frequency converter for converting output power of the induction generator into AC power having a predetermined frequency and extracting the AC power. A power generator including a rotation speed control device that keeps the rotation speed of the prime mover at a predetermined value by increasing or decreasing output power of the induction generator taken out through the stationary frequency conversion device, wherein the output of the power generation device is A function generator to which power is input, and an actual rotation speed set value such that the output voltage of the induction generator becomes a constant value based on the output of the function generator and the rotation speed set value of the prime mover. And a real rotation speed setting means for outputting the actual rotation speed set value as a set value to be compared with a detected rotation speed in the rotation speed control device.