WO2015190707A1

WO2015190707A1 - Output voltage control device for generator without field discharge resistor

Info

Publication number: WO2015190707A1
Application number: PCT/KR2015/004706
Authority: WO
Inventors: 류호선; 이의택; 이주현
Original assignee: 한국전력공사
Priority date: 2014-06-11
Filing date: 2015-05-12
Publication date: 2015-12-17
Also published as: KR101545253B1

Abstract

Provided is an output voltage control device for a generator without a field discharge resistor. The output voltage control device for a generator comprises: a rectifying unit for rectifying an alternating current power to a direct current power, a direct current link terminal for storing energy on the basis of the direct current power rectified by the rectifying unit, a main control unit for controlling the magnitude of a field current flowing through field windings of the generator using the energy stored in the direct current link terminal according to a pulse width modulation signal, and an auxiliary control unit for freewheeling the energy stored in the field windings to the direct current link terminal when a signal for a circuit breaker operation is applied. Therefore, the present invention can reduce the volume resulting from the field discharge resistor and configure the output voltage control device at a low cost by configuring a connection circuit breaker and a field circuit breaker as a single two-pole circuit breaker.

Description

Output voltage control device of generator without field discharge resistance

The present application relates to the control of the output voltage of the generator.

Recently, diesel generators are used for power supply in urban areas and large buildings. In constructing a diesel power generation system, the output voltage control device of the generator is an essential facility along with the speed control device.

Referring to the output voltage control device of such a generator, as shown by way of example in Figure 1, the input AC power (AC power) can be varied in size by the transformer 10, the transformer 10 The AC power whose size is changed by the rectifier 20 may be converted into DC power Vdc. Thereafter, energy based on the DC power source Vdc may be stored in the DC link terminal 40.

On the other hand, the charging control unit 30, the current limiting resistor (R1) and the connection breaker (SW4) is connected in parallel to operate to prevent the sudden energy storage of the DC link terminal (40).

The generator voltage controller 80 turns the switching element Q1 on and off by a pulse width modulation (PWM) signal, and is stored in the DC link terminal 40 during the turn-on period of the switching element Q1. The field current If flowing through the field winding 60 increases due to energy, and the field current If flowing through the field winding 60 decreases during the turn-off period of the switching element Q1. That is, since the field current If is in proportion to the output voltage of the generator, the magnitude of the output voltage of the generator can be controlled by controlling the average value of the field current If flowing through the field winding 60. .

On the other hand, the battery 70 is connected in parallel to the DC link terminal 40, the energy is stored by the input AC power (AC power), and when an abnormality or shortage of the AC power (AC power) occurs AC power ( AC power) may be replaced or supplemented to supply energy to the field winding 60.

On the other hand, as shown in Figure 1, the field discharge resistor (R1) is configured to be connected in parallel with the field winding 60, the field breaker 50 is operated during the abnormal operation of the generator (three poles) (SW1 is connected, SW2 to SW3 are open), so that the energy stored in the field winding 60 of the generator is discharged through the field discharge resistor R2.

In the case of the field discharge resistor (R1) used in the conventional output voltage control device described above has a disadvantage that occupies a large volume of space as the capacity of the generator increases. In addition, since the connection breaker (SW4) and the field breaker 50 is configured separately, there is a problem that the cost increases due to the use of a plurality of breakers.

For related patents, Korean Patent Publication No. 2009-0032528 (published: April 1, 2009)

The present application provides a device for controlling the output voltage of a generator that can reduce the volume due to the field discharge resistance and can be configured at a low cost.

According to one embodiment of the present invention, the rectifying unit for rectifying the AC power source to the DC power source; A direct current link stage for storing energy based on the direct current power source rectified by the rectifier; A main control unit controlling a magnitude of a field current flowing through a field winding of a generator using energy stored in the DC link terminal according to a pulse width modulation signal; And an auxiliary control unit for freewheeling the energy stored in the field winding to the DC link stage when the circuit breaker operation signal is applied.

According to an embodiment of the present invention, the main control unit may include: a first freewheeling diode configured to freewheel the energy stored in the field winding to the field winding; And transmitting energy stored in the DC link terminal to the field winding at turn-on, and freewheeling the energy stored in the field winding at the turn-off to the field winding through the first freewheeling diode, thereby increasing the magnitude of the field current. It may include a switching element for controlling.

According to an embodiment of the present invention, the auxiliary control unit may include: a second freewheeling diode configured to freewheel the energy stored in the field winding to the DC link terminal; And a field breaker configured to freewheel the energy stored in the field winding through the second freewheeling diode to the DC link terminal when the breaker operation signal is applied.

According to an embodiment of the present invention, the output voltage control device of the generator further includes a current limiting resistor and a connection circuit breaker connected in parallel to prevent sudden energy storage of the DC link stage, wherein the connection circuit breaker and the field circuit breaker May be configured as a two-pole breaker.

According to the embodiment of the present invention, the switching element may have a redundant structure in which two switching elements are connected in parallel.

According to another embodiment of the present invention, the rectifying unit for rectifying the AC power source to the DC power source; A direct current link stage for storing energy based on the direct current power source rectified by the rectifier; A first freewheeling diode for freewheeling the energy stored in the field winding to the field winding; A second freewheeling diode for freewheeling the energy stored in the field winding to the DC link stage; Transmitting energy stored in the DC link terminal to the field winding when turned on according to a pulse width modulation signal, and freewheeling the energy stored in the field winding to the field winding through the first freewheeling diode when turned off; A switching element for controlling the magnitude of the field current; And a field breaker for freewheeling the energy stored in the field winding to the DC link terminal through the second freewheeling diode when the breaker operation signal is applied.

According to one embodiment of the present invention, when a breaker operation signal is applied, the energy stored in the field winding is freewheeled to the DC link stage, thereby reducing the volume due to the field discharge resistance, and the connection breaker and the field breaker 2 By configuring a single pole breaker, the output voltage control device can be configured at low cost.

1 is a view showing an output voltage control device of a conventional generator.

It is a block diagram of the output voltage control apparatus of the generator by one Embodiment of this invention.

It is a flowchart explaining operation | movement at the time of turn-on of the switching element of the output voltage control apparatus of the generator by one Embodiment of this invention.

It is a wave form diagram explaining operation | movement at the time of turn-on of the switching element of the output voltage control apparatus of the generator by one Embodiment of this invention.

It is a flowchart explaining operation | movement at the time of turn-off period of the switching element of the output voltage control apparatus of the generator by one Embodiment of this invention.

4B is a waveform diagram illustrating an operation during a turn-off period of a switching element of an output voltage control device of a generator according to one embodiment of the present invention.

It is a flowchart explaining operation | movement when the circuit breaker operation signal is applied to the field circuit breaker of the output voltage control apparatus of the generator by one embodiment of the present invention.

5B is a waveform diagram illustrating an operation when a circuit breaker operation signal is applied to a field circuit breaker of an output voltage control device of a generator according to one embodiment of the present invention.

6 is a flowchart illustrating a method of controlling the output voltage of a generator according to one embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, embodiments of the present invention may be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below. Shapes and sizes of the elements in the drawings may be exaggerated for clarity, elements denoted by the same reference numerals in the drawings are the same elements.

2 is a configuration diagram of an output voltage control device of a generator according to an embodiment of the present invention, which includes an AC power supply (AC power supply), a transformer 10, a rectifier 20, a charge control unit 30, and a DC link terminal 40. And a main control unit 210 and an auxiliary control unit 220, the main control unit 210 includes a switching element Q1 and a first freewheeling diode D1, and the auxiliary control unit 220 includes a field breaker SW5. ) And a second freewheeling diode D2.

3A to 3B are views for explaining the operation during the turn-on period of the switching element of the output voltage control device of the generator according to the embodiment of the present invention, and FIGS. 4A to 4B illustrate one embodiment of the present invention. Is a view for explaining the operation during the turn-off period of the switching element of the output voltage control device of the generator according to Figure 5a to 5b is a circuit breaker in the field circuit breaker of the output voltage control device of the generator according to an embodiment of the present invention It is a figure for explaining the operation | movement when an operation signal is applied.

Hereinafter, an output voltage control device of a generator according to an embodiment of the present invention will be described in detail with reference to FIGS. 2 to 5B.

As shown in FIG. 2, the transformer 10 converts an input AC power (AC power) into an AC power having an appropriate size according to the turns ratio, and the converted AC power is converted into a rectifier 20 including a plurality of diodes. It may be rectified to a direct current power source (Vdc). Thereafter, energy based on the DC power supply Vdc may be stored in the DC link terminal 40 in which two capacitors C1 and C2 are connected in series.

On the other hand, the charging control unit 30, the current limiting resistor (R1) and the connection breaker (SW6) is connected in parallel to operate to prevent the sudden energy storage of the DC link terminal 40, the connection breaker (SW6) and the field breaker ( SW5) may be a two-pole breaker (ie, connection breaker SW6 and field breaker SW5 one of the two poles of the two-pole breaker) operating simultaneously according to one CBO signal.

In addition, the battery 70 is connected to the DC link terminal 40 in parallel, and the energy is stored by the input AC power (AC power), and when an abnormality or shortage of the AC power (AC power) occurs, the AC power ( AC power) may be replaced or supplemented to supply energy to the field winding 60.

Meanwhile, the main controller 210 determines the magnitude of the field current If flowing through the field winding 60 of the generator using energy stored in the DC link terminal 40 according to the pulse width modulation signal Vg (Q1). Can be controlled. The main controller 210 described above is provided between the cathode of the first freewheeling diode D1 and the first freewheeling diode D1 connected in parallel to the field winding 60 and the positive terminal of the DC link terminal 40. It may include a connected switching element (Q1).

Herein, the switching element Q1 may include an insulated gate bipolar transistor (IGBT), a field-effect transistor (FET), a gate turn-off thyristor (GTO), and a junction. It may be any one of a semiconductor switch including a bipolar junction transistor (BJT). In addition, although one switching element Q1 is illustrated in FIG. 2, two switching elements may have a redundant structure connected in parallel. In this case, two switching elements connected in parallel according to the pulse width modulation signal Vg (Q1) may be used. The devices can operate simultaneously. Thus, by using the switching element in a redundant structure, there is an advantage that can increase the reliability.

First, when the switching element Q1 is turned on, energy stored in the DC link terminal 40 may be transmitted to the field winding 60.

Specifically, as shown in FIG. 3A, when the switching element Q1 is turned on, the energy stored in the DC link terminal 40 during the turn-on period (see Ton in FIG. 3B) is as shown in the path P1. , May be transmitted to the field winding 60 through the switching element Q1 (the field breakers SW5 and SW6 are connected).

That is, as shown in FIG. 3B, during the turn-on period Ton by the pulse width modulation signal Vg (Q1), the voltage Vo at both ends of the field winding 60 is changed to the DC voltage of the DC link terminal 40. Vdc), and the current flowing through the field winding 60 by this DC voltage Vdc is increased to satisfy the following equation (1). Meanwhile, if not described, if_ref may be a reference value to be followed by the field current flowing through the field winding 60.

[Equation 1]

Here, Vdc may be a DC voltage of the DC link terminal, Lf may be an inductor of the field winding, if may be a field current, and Rf may be an internal resistance of the field winding.

Meanwhile, when the switching element Q1 is turned off, energy stored in the field winding 60 may be freewheeled into the field winding 60 through the first freewheeling diode D1.

Specifically, as shown in FIG. 4A, when the switching element Q1 is turned off, the energy stored in the field circle 60 during the turn-off period (see Toff in FIG. 4B) is as shown in the path P2. It may be freewheeled by the field winding 60 (in this case, the field breakers SW5 and SW6 are connected).

That is, as shown in FIG. 4B, the voltage Vo between both ends of the field winding 60 is zero voltage during the turn-off period Toff by the pulse width modulation signal Vg (Q1), and the field winding 60 Due to the internal resistance, the field current If decreases to satisfy Equation 2 below.

[Equation 2]

Here, Lf may be an inductor of the field winding, if may be a field current, and Rf may be an internal resistance of the field winding.

As such, the magnitude of the field current If may be controlled by adjusting the duty of the pulse width modulated signal Vg (Q1) applied to the gate of the switching element Q1.

That is, as described in Equation 3 below, since the magnitude of the field current If is proportional to the output voltage Vt of the generator, the magnitude of the field current If flowing through the field winding 60 is controlled. By doing this, the magnitude of the output voltage of the generator can be controlled.

[Equation 3]

Vt = K × φ × N

Here, Vt is the output voltage of the generator, K is a constant, φ is a magnetic flux is a value proportional to the field current (If), N is the rotational speed of the generator.

On the other hand, when the breaker operation signal (Circuit Breaker Operatiom CBO) is applied, the auxiliary control unit 220 may freewheel the energy stored in the field winding (60) to the DC link terminal 40. Here, the breaker operation signal (CBO) may be an operation signal that can be input manually by the operator when the main control unit 210 failure.

The auxiliary control unit 220 includes a field breaker SW5 connected between the anode of the first freewheeling diode D1 and the field winding 60, and the anode of the first freewheeling diode D1 and the field winding of the first freewheeling diode D1. The cathode connected to the connection terminal 60 may include a second freewheeling diode D2 connected to the positive terminal of the DC link terminal 40.

Specifically, as shown in FIGS. 5A and 5B, when the breaker operation signal CBO is applied, the field breaker SW5 is connected, and the energy stored in the field winding 60 is shown in the path P3. As described above, the field breaker SW5 may be freewheeled to the DC link terminal 40 through the second freewheeling diode D2. Accordingly, the field current If may be reduced to satisfy Equation 4 below.

[Equation 4]

As described above, according to one embodiment of the present invention, when the breaker operation signal is applied, by freewheeling the energy stored in the field winding to the DC link terminal, it is possible to reduce the volume due to the field discharge resistance, the connection breaker By configuring the field circuit breaker with one 2-pole circuit breaker, the output voltage control device can be configured at low cost.

6 is a flowchart for explaining an output voltage control method of a generator according to one embodiment of the present invention.

Hereinafter, a method of controlling an output voltage of a generator will be described with reference to FIGS. 2 to 6. However, description of overlapping parts with respect to FIG. 2 will be omitted for simplicity of the invention.

2 to 6, first, the rectifier 20 may rectify an AC power source (AC power source) into a DC power source (Vdc) (S601). DC power (Vdc) rectified by the rectifier 20 may be transmitted to the DC link terminal 40.

Next, the DC link stage 40 may store energy based on the DC power supply Vdc rectified by the rectifying unit 20 (S602).

Next, the main controller 210 determines the magnitude of the field current If flowing through the field winding 60 of the generator using energy stored in the DC link terminal 40 according to the pulse width modulation signal Vg (Q1). It can be controlled (S603). The main controller 210 described above is provided between the cathode of the first freewheeling diode D1 and the first freewheeling diode D1 connected in parallel to the field winding 60 and the positive terminal of the DC link terminal 40. It may include a connected switching element (Q1).

Lastly, when the breaker operation signal CBO is applied, the auxiliary controller 220 may freewheel the energy stored in the field winding 60 to the DC link terminal 40 (S604). Here, the breaker operation signal (CBO) may be an operation signal that can be input manually by the operator when the main control unit 210 is broken, the auxiliary control unit 220, the anode of the first freewheeling diode (D1) and (+) Terminal of the DC link terminal 40 where an anode cathode is connected to the field breaker SW5 connected between the field winding 60 and the anode of the first freewheeling diode D1 and the field winding 60. It may include a second freewheeling diode (D2) connected to.

The present application is not limited by the above-described embodiment and the accompanying drawings. It is intended that the scope of the invention be defined by the appended claims, and that various forms of substitution, modification, and alteration can be made without departing from the spirit of the invention as set forth in the claims. Will be self-explanatory.

Claims

Rectifier for rectifying AC power to DC power;

A direct current link stage for storing energy based on the direct current power source rectified by the rectifier;

A main control unit controlling a magnitude of a field current flowing through a field winding of a generator using energy stored in the DC link terminal according to a pulse width modulation signal; And

When the breaker operation signal is applied, the auxiliary control unit for freewheeling the energy stored in the field winding to the DC link stage,

The main control unit,

And a first freewheeling diode to freewheel the energy stored in the field winding to the field winding when the breaker operation signal is not applied, and to freewheel the energy stored in the field winding to the DC link stage when the breaker operation signal is applied. and,

The auxiliary control unit,

A second freewheeling diode for freewheeling the energy stored in the field winding to the DC link stage; And

When the circuit breaker operation signal is applied, the output voltage control device of the generator including a field breaker for freewheeling the energy stored in the field winding to the DC link through the first freewheeling diode and the second freewheeling diode .
The method of claim 1,

The main control unit,

Controlling the magnitude of the field current by transmitting energy stored in the DC link stage to the field winding at turn-on, and freewheeling the energy stored in the field winding at the turn-off to the field winding through the first freewheeling diode. An output voltage control device for a generator further comprising a switching element.
The method of claim 1,

The output voltage control device of the generator,

Further comprising a parallel connected current limiting resistor and a breaker for preventing sudden energy storage of the DC link stage,

The connection breaker and the field breaker, the output voltage control device of the generator consisting of a two-pole breaker.
The method of claim 2,

The switching device,

An output voltage control device of a generator having a redundant structure in which two switching elements are connected in parallel.