KR101339180B1 - Automatic Voltage Regulator based on Series Voltage Compensation with AC Chopper - Google Patents

Abstract

The present invention relates to a series voltage compensation based automatic voltage regulator having an AC chopper. The automatic voltage regulator according to the present invention is composed of an AC chopper and a transformer for series voltage compensation, and the AC chopper used in the automatic voltage regulator is a commutator. Since the commutation problem is solved and direct AC power conversion is done, no energy storage device is required, which reduces the size and cost of the automatic voltage regulator, and because of the transformer for series compensation, the AC chopper is just for compensation. Only the necessary voltages need to be compensated, reducing the rating of the switch. In addition, since the automatic voltage regulator according to the present invention can make the compensation voltage in phase or reverse phase of the input voltage, it can quickly compensate for all the increase or decrease of the input voltage.

Description

Automatic Voltage Regulator based on Series Voltage Compensation with AC Chopper}

The present invention relates to a series voltage compensation based automatic voltage regulator having an AC chopper which quickly compensates for voltage sag and voltage swell of an input voltage using an AC chopper and a transformer for series voltage compensation. .

Automatic Voltage Regulator (AVR) is a device that automatically regulates the output voltage. Sudden reduction or increase in supply voltage in power sensitive equipment such as computers, communication equipment, process control systems, etc. can cause serious problems for the system. As the use of such power sensitive equipment increases, the drop and rise of the supply voltage is recognized as an important power quality problem. Therefore, many methods for solving this power quality problem have been studied.

In order to solve the conventional power quality problem, a dynamic voltage restorer (DVR) having a DC-link capacitor has been proposed. These DVRs are designed to protect sensitive loads from voltage dips and spikes, but use indirect AC-AC power conversion, which can lead to problems such as the use of more power semiconductor devices, more losses and less efficiency than direct AC-AC power conversion. have. In addition, since the DVR uses a DC-link capacitor which is an energy storage element, its size increases and maintenance is difficult.

To overcome this drawback, an automatic voltage regulator with pulse width modulated (PWM) ac choppers has been proposed, but the bidirectional switch used in the AC chopper has high commutation problems. This can cause problems such as voltage spikes and limited power ratings.

Although an automatic voltage regulator that performs a series voltage compensation using an AC chopper and a series transformer without the commutation problem has been proposed, such a automatic voltage regulator has a problem in that it can be compensated only for the decrease or increase of the supply voltage. .

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and a series voltage compensation based automatic voltage regulator having an AC chopper which quickly compensates for a drop and rise of an input voltage using an AC chopper and a transformer for series voltage compensation. It is to provide.

To this end, the series voltage compensation based automatic voltage regulator having an AC chopper according to the present invention includes an AC chopper for converting and outputting an AC voltage at a predetermined ratio, a transformer for compensating the input voltage with a compensation voltage in series, and A bypass circuit for determining the phase of the compensation voltage, a voltage detector for detecting the input voltage, a polarity detector for detecting the polarity of the input voltage, an input voltage detected by the voltage detector and the polarity detector And a controller for controlling the switches of the AC chopper based on the polarity of the input voltage.

The present invention can quickly compensate for the drop or rise of the input voltage by making the compensation voltage in phase or reverse phase of the input voltage using an AC chopper providing a direct AC power conversion and a transformer for series voltage compensation.

In addition, since the present invention is a direct AC power conversion through the AC chopper, there is no need to provide a separate element for storing energy, thereby reducing the size and cost of the automatic voltage regulator.

In addition, since the present invention includes a transformer for series voltage compensation, only the compensation voltage needs to be compensated through the AC chopper, thereby reducing the rating of the switch.

1 is a block diagram of an automatic voltage regulator according to an embodiment of the present invention.
FIG. 2 shows a switch driving signal of the automatic voltage regulator shown in FIG. 1.
3 shows an operating waveform of an automatic voltage regulator according to an embodiment of the present invention.
4 shows an operation mode of the automatic voltage regulator according to the present invention.
FIG. 5 shows an equivalent circuit for the automatic voltage regulator shown in FIG. 1.
6 shows an experimental waveform of an automatic voltage regulator according to the present invention.
7 is a block diagram of a three-phase automatic voltage regulator according to another embodiment of the present invention.

Hereinafter, a series voltage compensation based automatic voltage regulator having an AC chopper according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram of an automatic voltage regulator according to an embodiment of the present invention. In this embodiment, an automatic voltage regulator having a single phase ac chopper will be described as an example.

As shown in FIG. 1, the automatic voltage regulator 100 according to the present invention includes an AC chopper 110 that provides AC power conversion, a transformer 120 for series voltage compensation, and a bypass circuit. 130, a voltage detector 140, a polarity detector 150, and a controller 160.

AC chopper 110 is composed of a switching unit, a filter, a DC snubber (dc snubber).

,

,

,

)로 구성되며, 이러한 스위치(

,

,

,

)는 전력용 반도체 스위치로 구현된다. 상기 제1 내지 제4스위치(

,

,

,

)의 게이트로 입력되는 구동 신호의 듀티비(duty ratio)를 조절하여 교류 쵸퍼(110)의 출력전압(

)을 조절한다.The switch includes first to fourth switches (

,

,

,

), These switches (

,

,

,

) Is implemented as a power semiconductor switch. The first to fourth switches (

,

,

,

The output voltage of the AC chopper 110 by adjusting the duty ratio of the driving signal input to the gate of

).

The filter is a low pass filter (LPF) composed of an inductor (L) and a capacitor (C), and removes harmonic components from the output of the AC chopper 110.

)로 구성되며, 그 중 하나의 스너버 커패시터(

)는 상기 제1스위치(

) 및 제3스위치(

)와 병렬로 연결되며, 다른 하나의 스너버 커패시터(

)는 상기 제2스위치(

) 및 제4스위치(

)와 병렬로 연결된다. 상기 직류 스너버는 상기 필터의 인덕터(L)에 저장되는 에너지를 흡수하여 상기 스위치들(,

,

,

)의 스트레스를 감소시키는 역할을 한다.DC snubbers have two snubber capacitors (

) And one snubber capacitor (

) Is the first switch (

) And the third switch (

) In parallel with the other snubber capacitor (

) Is the second switch (

) And fourth switch (

) In parallel. The DC snubber absorbs the energy stored in the inductor (L) of the filter so that the switches ( ,

,

,

) To reduce stress.

)을 보상전압(

)으로 변환한다. 상기 변압기(120)는 입력전압(

)에 보상전압을 직렬보상하여 일정한 출력전압(

)을 유지하게 한다. 그리고, 상기 변압기(120)의 권선비는 입력전압의 최대 변동 범위에 의존한다.Transformer 120 is the output voltage of the AC chopper (110)

) To the compensation voltage (

). The transformer 120 is an input voltage (

) By compensating the compensation voltage in series

To keep). The winding ratio of the transformer 120 depends on the maximum variation range of the input voltage.

The bypass circuit 130 is positioned between the output terminal of the AC chopper 110 and the primary side of the transformer 120 and is composed of a switch such as a triac or a thyristor. The bypass circuit 130 allows current to flow in both directions, so that when a short circuit occurs in the automatic voltage regulator 100, the primary side of the transformer 120 is shorted to be generated at the primary side of the transformer 120. It serves to protect the AC chopper 110 from large current.

For example, when a short circuit occurs, a large current is generated at the primary side of the transformer 120, and when the large current flows through the AC chopper 110, the main winding of the transformer 120 is an open circuit. AC chopper 110 is destroyed because it can not operate at. As a result, since the automatic voltage regulator 100 may be seriously damaged, the bypass circuit 130 is used to prevent the AC chopper from being damaged by the large current.

,

)를 통하여 순환하게 되어 단락회로의 전류로부터 자동전압조절기(100)를 보호할 수 있게 된다. The bypass circuit 130 allows the secondary current of the transformer 120 to flow to the bypass circuit 130 when a short circuit occurs. Therefore, the current of the bypass circuit 130 is the first and second bypass switch (

,

By circulating through) it is possible to protect the automatic voltage regulator 100 from the current of the short circuit.

)의 변동에 따라 제1바이패스 스위치(

)와 제2바이패스 스위치(

)를 온/오프(on/off) 시킨다. 다시 말해서, 입력전압(

)의 강하가 감지되면, 제1바이패스 스위치(

)는 켜지고, 제2바이패스 스위치(

)는 꺼진다. 이때, 보상전압(

)은 입력전압(

)의 위상과 동일하며, 상기 보상전압(

)을 입력전압(

)에 더해 전압강하를 보상할 수 있다. 한편, 전압상승이 검출되면, 제1바이패스 스위치(

)는 꺼지고, 제2바이패스 스위치(

)는 켜진다. 이때, 보상전압(

)은 입력전압(

)의 위상과 반대되는 역상으로, 입력전압(

)으로부터 보상전압(

)을 빼 전압상승을 보상한다.In addition, the bypass circuit 130 serves to determine the phase of the compensation voltage. The bypass circuit 130 is an input voltage (

), The first bypass switch (

) And the second bypass switch (

To turn on / off. In other words, the input voltage (

When the drop of the) is detected, the first bypass switch (

) Is turned on and the second bypass switch (

) Is turned off. At this time, the compensation voltage (

) Is the input voltage (

Is equal to the phase of the compensation voltage

) Input voltage (

) Can compensate for the voltage drop. On the other hand, if a voltage increase is detected, the first bypass switch (

) Turns off and the second bypass switch (

) Is turned on. At this time, the compensation voltage (

) Is the input voltage (

Reversed to the phase of), the input voltage (

Compensation voltage from

) To compensate for the voltage rise.

)을 검출하여 그 검출된 입력전압(

)을 디지털 신호로 변환하여 출력한다. 본 발명에서는 입력전압(

)만 검출하는 것을 예로 들어 설명하고 있으나, 출력전압(

)도 검출하여 출력전압(

)이 일정한 전압으로 유지되는지를 모니터링하도록 구현할 수도 있다.The voltage detector 140 inputs an input voltage inputted to the automatic voltage regulator 100 (

) And the detected input voltage (

) Is converted into a digital signal and output. In the present invention, the input voltage (

For example, detecting only), but output voltage (

) Is also detected and the output voltage (

) Can be implemented to monitor whether the voltage remains constant.

)의 극성을 검출한다.The polarity detector 150 inputs an input voltage inputted to the automatic voltage regulator 100 (

) Polarity is detected.

)에 따라 상기 교류 쵸퍼(110)의 제1 내지 제4스위치(

,

,

,

)의 구동신호 듀티비를 제어한다. 또한, 상기 제어부(160)는 상기 극성검출부(150)에 의해 검출된 입력전압(

)의 극성에 따라 상기 교류 쵸퍼(110)의 제1 내지 제4스위치(

,

,

,

)의 스위칭 패턴을 제어한다.The controller 160 controls the input voltage detected through the voltage detector 140.

According to the first to fourth switches of the AC chopper 110 (

,

,

,

Control the driving signal duty ratio. In addition, the controller 160 controls the input voltage detected by the polarity detector 150.

According to the polarity of the first to fourth switches of the AC chopper 110 (

,

,

,

Control the switching pattern.

) 및 제2바이패스 스위치(

)의 턴온/턴오프(turn-on/turn-off)을 제어하여 보상전압(

)의 위상을 결정한다.The controller 160 may include a first bypass switch of the bypass circuit 130.

) And second bypass switch (

Control the turn-on / turn-off of

) Is determined.

The automatic voltage regulator 100 composed of the above components regulates the output voltage by adjusting the duty ratio of the driving signal, and determines the switching pattern according to the polarity of the input voltage. An operation mode of the automatic voltage regulator 100 according to the switch driving of the automatic voltage regulator 100 will be described with reference to FIGS. 2 and 3.

FIG. 2 shows a switch driving signal of the automatic voltage regulator shown in FIG. 1.

는 안전한 통신을 위한 데드타임(dead time)이고,

는 스위칭 기간이고, D는 제1스위치 구동신호와 제2스위치 구동신호의 듀티비이다. 스위치 구동신호의 스위칭 패턴은 표 1과 같다.2,

Is the dead time for secure communication,

Is a switching period, and D is a duty ratio of the first switch driving signal and the second switch driving signal. The switching pattern of the switch driving signal is shown in Table 1.

>0) 동안 제2스위치(

)와 제4스위치(

)는 도통되고, 제1스위치(

)와 제3스위치(

)는 소정 듀티비에 의해 상보적으로 동작한다. 이때, 전류 스파이크를 방지하기 위해 제1스위치(

)와 제3스위치(

) 동작시 데드타임이 존재한다. 한편, 입력전압이 음의 값을 가지는 구간(

0) 동안, 제1스위치(

)와 제3스위치(

)는 도통되고, 제2스위치(

)와 제4스위치(

)는 소정 듀티비에 의해 상보적으로 동작한다. 이때, 전류 스파이크를 방지하기 위해 제2스위치(

)와 제4스위치(

) 동작시 데드타임이 존재한다.Period in which the input voltage has a positive value

The second switch (> 0)

) And the fourth switch (

) Is turned on and the first switch (

) And the third switch (

) Is complementary by a certain duty ratio. In this case, the first switch (

) And the third switch (

) Dead time exists during operation. On the other hand, the section in which the input voltage has a negative value (

0), the first switch (

) And the third switch (

) Is turned on and the second switch (

) And the fourth switch (

) Is complementary by a certain duty ratio. At this time, in order to prevent current spikes, the second switch (

) And the fourth switch (

) Dead time exists during operation.

,

,

,

)가 켜지면 단락회로(short circuit)가 발생하고, 모든 스위치(

,

,

,

)가 꺼지면 전압 스파이크가 스위치들(

,

,

,

)에 피해를 입혀 커뮤테이션(commutation)(전류의 방향 변경) 문제가 발생한다. 상기 스위치들(

,

,

,

)의 전류 스파이크에 의한 피해를 방지하기 위해 데드타임이 필요하고, 전압 스파이크를 방지하기 위해 인덕터 전류가 흐를 수 있는 전류 경로가 필요하다. 이러한 커뮤테이션 문제를 해결하기 위해 스위칭 패턴은 입력전압의 극성에 의해 결정된다.All switches (

,

,

,

) Is on, a short circuit occurs, and all switches (

,

,

,

) Turns off the voltage spikes

,

,

,

), Causing commutation (change of direction of current). The switches (

,

,

,

Dead time is required to prevent damage caused by current spikes, and a current path through which the inductor current can flow is required to prevent voltage spikes. To solve this commutation problem, the switching pattern is determined by the polarity of the input voltage.

)의 반주기 동안 두 개의 스위치는 도통되고, 나머지 두 개의 스위치만 소정 듀티비에 의해 스위칭 동작하기 때문에 4개의 스위치를 모두 스위칭하는 방식에 대비하여 스위칭 손실을 줄일 수 있다.Automatic voltage regulator 100 according to the present invention is the input voltage (

Since the two switches are turned on during the half cycle of), and only the other two switches are operated by a predetermined duty ratio, the switching loss can be reduced compared to the method of switching all four switches.

Figure 3 shows the operating waveform of the automatic voltage regulator according to an embodiment of the present invention, Figure 4 shows the operating mode of the automatic voltage regulator according to the present invention.

In the voltage drop condition, the compensation voltage has the same phase as the input voltage as shown in FIG. In the voltage rising condition, the compensation voltage has a phase opposite to that of the input voltage as shown in FIG.

)는 턴온(turn-on)되고, 제2바이패스 스위치(

)는 턴오프(turn-off)된다.The automatic voltage regulator 100 according to the present invention has four operation modes during the switching period as shown in FIG. In this specification, each operation mode will be described under a voltage drop condition. In the voltage drop condition, the first bypass switch (

) Is turned on and the second bypass switch (

) Is turned off.

,

]는 제1스위치와 제2스위치가 온되는 구간이다. 이때, 인턱터 전류

는 인덕터 전류

가 0을 초과하는 동안(

>0) 도 4(a)에 도시된 바와 같이 제2스위치와 마주한 다이오드와 제1스위치(

)를 거쳐 도통한다. 상기 인덕터 전류

는 인덕터 전류

가 0 미만인 동안 도 4(b)와 같이 제1스위치와 마주한 다이오드와 제2스위치(

)를 도통한다. 따라서, 인덕터 전류(

)는 출력으로 에너지를 제공하도록 입력측과 출력측을 도통한다.First operation mode [

,

] Is the section in which the first switch and the second switch is turned on. At this time, the inductor current

Inductor current

Is greater than 0 (

> 0) As shown in FIG. 4 (a), the diode and the first switch facing the second switch (

Through) The inductor current

Inductor current

Is less than 0, the diode and the second switch facing the first switch as shown in FIG.

Turn on). Therefore, the inductor current (

) Conducts input and output sides to provide energy to the output.

)은 다음 수학식 1과 같이 나타낼 수 있다.Inductor voltage (

) May be expressed as in Equation 1 below.

Since the input voltage is larger than the output voltage of the AC chopper, the current through the inductor is increased in the first operation mode, and the energy of the inductor is charged.

,

]는 스위치들의 데드 타임으로 정의되고, 안전한 커뮤테이션을 위해 중요하다. 도 2(a)에 도시된 바와 같이 입력전압이 0을 초과하면, 이 모드는 제1스위치와 제3스위치의 데드타임으로 정의된다. 제2스위치와 제4스위치는 안전한 커뮤테이션을 위해 턴온된다. 인덕터 전류가 0을 초과하면 인덕터 전류는 도 4(c)와 같이 제3스위치와 마주하는 다이오드와 제4스위치를 사용하여 출력측을 통해 바이패스된다. 인덕터 전류가 0미만인 경우, 인덕터 전류는 도 4(d)와 같이 제1스위치 맞은편 다이오드와 제2스위치를 통해 출력측을 통해 바이패스된다. 입력전압이 0미만이면 이 모드는 도 2(b)에 도시된 바와 같이 제2스위치 및 제4스위치의 데드타임으로 정의된다. 제1스위치와 제3스위치는 안전한 커뮤테이션을 위해 턴온된다. 인덕터 전류가 0을 초과하면 인덕터 전류는 도 4(e)와 같이 제3스위치와 제4스위치의 맞은편 다이오드를 사용하여 출력측을 통해 바이패스된다. 인덕터 전류가 0미만이면 인덕터 전류는 도 4(f)와 같이 제2스위치와 마주한 다이오드와 제1스위치를 사용하여 출력측을 통해 바이패스된다. 그러므로, 인덕터 전류를 위한 전류 경로는 이 모드에서 모든 전류 방향으로 항상 존재한다.Second operation mode [

,

] Is defined as the dead time of the switches and is important for safe commutation. As shown in FIG. 2A, when the input voltage exceeds 0, this mode is defined as the dead time of the first switch and the third switch. The second and fourth switches are turned on for safe commutation. When the inductor current exceeds 0, the inductor current is bypassed through the output side using a diode and a fourth switch facing the third switch as shown in FIG. When the inductor current is less than zero, the inductor current is bypassed through the output side through the diode and the second switch opposite the first switch as shown in FIG. If the input voltage is less than 0, this mode is defined as the dead time of the second switch and the fourth switch as shown in FIG. The first and third switches are turned on for safe commutation. If the inductor current exceeds 0, the inductor current is bypassed through the output side using diodes opposite the third and fourth switches as shown in FIG. If the inductor current is less than 0, the inductor current is bypassed through the output side using the diode and the first switch facing the second switch as shown in FIG. 4 (f). Therefore, the current path for the inductor current is always present in all current directions in this mode.

,

]에서는 도 2에 도시된 바와 같이 제3스위치와 제4스위치가 턴온된다. 이 모드는 제1모드와 상호보완적이다. 인덕터 전류는 인덕터 전류가 0을 초과하는 구간에서 도 4(g)와 같이 제4스위치와 제3스위치 맞은편 다이오드를 통해 도통된다. 인덕터 전류는 0 미만인 구간에서 도 4(h)와 같이 제4스위치 맞은편 다이오드와 제3스위치를 통해 도통된다. 따라서, 제3모드에서 인덕터 전류는 제3스위치와 제4스위치를 통해 자유롭게 흐른다. 인덕터 전압(

)은 아래 수학식 2와 같다.3rd mode [

,

], The third switch and the fourth switch is turned on as shown in FIG. This mode is complementary to the first mode. The inductor current is conducted through the diode opposite the fourth switch and the third switch as shown in FIG. 4 (g) in the period where the inductor current exceeds zero. The inductor current is conducted through the diode opposite the fourth switch and the third switch as shown in FIG. Therefore, in the third mode, the inductor current flows freely through the third switch and the fourth switch. Inductor voltage (

) Is shown in Equation 2 below.

Therefore, the current through the inductor decreases, and the energy stored in the inductor is discharged.

,

]의 동작은 제2모드의 동작과 유사하여 그 설명은 생략한다.4th mode [

,

] Operation is similar to that of the second mode, and description thereof will be omitted.

Short circuits in the switching pattern are not caused by dead time. On the other hand, the current path for the inductor current always exists in all current directions. Therefore, the commutation problem is solved through this switching pattern.

The operation mode under the voltage rising condition is similar to the operation mode under the voltage drop condition except that the first bypass switch is turned off and the second bypass switch is turned on, and thus the description of this condition is omitted.

Hereinafter, for the technical analysis of the automatic voltage regulator according to the present invention, it will be described with reference to the equivalent circuit for the automatic voltage regulator according to the embodiment of the present invention shown in FIG. Here, it is assumed that the dead time is ignored for analysis and satisfies the condition as shown in Equation (3).

는 각주파수이다. 수학식 3에 따르면 수학식 4와 같은 가정이 가능하다.here,

Is the angular frequency. According to Equation 3, the same assumption as in Equation 4 is possible.

)은 수학식 5로부터 구할 수 있다.These conditions meet the practical filter design. Average voltage modulated by the chopper (

) Can be obtained from equation (5).

) 동안 일반화된 방정식은 수학식 6 및 7를 통해 구할 수 있다.Therefore, the switching interval (

The generalized equations can be obtained from equations (6) and (7).

은 변압기권선비

이다. 전압하강 조건하에 수학식 6 및 수학식 7은 하기 수학식 8 및 수학식 9와 같이 변환된다.here,

Silver transformer winding ratio

to be. Equations 6 and 7 are converted as shown in Equations 8 and 9 under the voltage drop condition.

Reflecting Equation 9 in Equation 8, the differential equation as shown in Equation 10 is as follows.

The transfer function from Equation 10 is equal to Equation 11.

Therefore, the total voltage gain can be defined as in Equation 12.

Using Equation 3, the total voltage gain is simplified as in Equation 13.

 Using Equation 4, the ideal total voltage gain under voltage drop condition can be simplified as shown in Equation 14.

Similarly, the total voltage gain in the voltage rising condition is expressed by Equation 15.

Using equation (3), the total voltage gain is simplified as in equation (16).

Using Equation 4, the ideal overall voltage gain under voltage rise condition is simplified to Equation 17.

The turns ratio of the transformer depends on the maximum fluctuation range of the input voltage and the required turns ratio is based on the percentage of the compensation voltage. The percentage of compensation voltage is defined as in Equation 18.

과

은 최소 허용입력전압과 공칭 전압(nominal voltage)을 각각 나타낸다. 권선수를 설계하는 방정식은 수학식 19와 같이 정의된다.here,

and

Denotes the minimum allowable input voltage and the nominal voltage, respectively. The equation for designing the number of turns is defined as in Equation 19.

The ripple of the inductor current can be derived from equation (20).

는 스위칭 주파수이다. 그러므로, 인덕터는 스위칭 주파수, 리플 전류와 듀티비에 의해 결정된다. 커패시터의 리플은 식 21로부터 유도될 수 있다.here,

Is the switching frequency. Therefore, the inductor is determined by the switching frequency, ripple current and duty ratio. The ripple of the capacitor can be derived from equation (21).

Therefore, the capacitor is determined by the switching frequency, the ripple voltage, and the ripple current.

5 shows an experimental waveform of an automatic voltage season according to the present invention.

로 설계되었으며, 입력전압과 출력전압의 공칭전압은

,

의 교류 전압이다. 스위칭 주파수는

이고, 데드타임은

이며, 부하는 순수한 저항 부하이다. 자동전압절기(100)의 다른 파라미터는

,

,

,

,

이다.Here, the automatic voltage season 100 used in the experiment is rated 3

The nominal voltage of input voltage and output voltage is

,

AC voltage. Switching frequency

And dead time

And the load is a pure resistive load. Other parameters of the automatic voltage season 100

,

,

,

,

to be.

로 보상된다. 실험에서와 같이, 본 발명에 따른 자동전압절기(100)는 입력전압의 하강 및 상승에 대해 빠르게 보상할 수 있다.When the input voltage drops or rises by 25%, the waveforms of the input voltage and the output voltage are the same as those of Figs. 5 (a) and 5 (b), respectively. Output voltage is required in half cycle

To be compensated. As in the experiment, the automatic voltage season 100 according to the present invention can quickly compensate for the falling and rising of the input voltage.

In the present specification, a case of controlling the single-phase AC voltage using the single-phase AC chopper has been described as an example. However, the automatic voltage regulator 100 proposed in the present invention may be applied to the three-phase AC voltage control.

For example, as shown in Figure 7, the three-phase automatic voltage regulator for controlling the three-phase AC voltage receives the input voltage between each phase of the three-phase line voltage (input voltage) and the voltage of each input line voltage It consists of three automatic voltage regulators 100 to compensate for the voltage between each phase according to the change. Then, the phase of the compensation voltage for the line voltage between each phase output from the transformer 120 of the automatic voltage regulator 100 is adjusted according to the phase of the input voltage of each phase. In other words, the three automatic voltage regulators 100 are voltages for respective phase input voltages of the three-phase input voltages R, S, and T input to the input terminals A and B of the automatic voltage regulator 100, respectively. The three-phase output voltages U, V, and W are output through the output terminals C, D of the automatic voltage regulator 100, respectively.

The present invention as described above is not limited to the configuration and method of the embodiments described above, the embodiments may be configured by selectively combining all or part of each embodiment so that various modifications can be made It may be.

100: automatic voltage regulator
110: AC chopper
120: transformer
130: bypass circuit
140: voltage detector
150: phase detection unit
160:

Claims (10)

An AC chopper for converting an input voltage into an AC power at a predetermined ratio and outputting the same;
A transformer for compensating the input voltage in series with a compensation voltage;
A bypass circuit for determining a phase of the compensation voltage;
A voltage detector detecting the input voltage;
A polarity detector for detecting the polarity of the input voltage;
And a controller for controlling the switches of the AC chopper based on the input voltage detected by the voltage detector and the polarity of the input voltage detected by the polarity detector. Voltage regulator. The method according to claim 1, wherein the AC chopper,
A switching unit comprising first to fourth switches for adjusting the output voltage of the AC chopper;
A filter for removing harmonic components from the output voltage of the AC chopper;
And a direct current snubber absorbing energy stored in the inductor of the filter. The method of claim 2, wherein the first to fourth switches,
A series voltage compensation based automatic voltage regulator having an AC chopper, characterized by being implemented as a power semiconductor switch. 3. The filter according to claim 2,
A series voltage compensation based automatic voltage regulator having an alternating current chopper comprising an inductor and a capacitor. The method of claim 2, wherein the DC snubber,
It consists of two snubber capacitors, one of which snubber capacitor is connected in parallel with the first switch and the third switch, the other snubber capacitor is connected in parallel with the second switch and the fourth switch Series voltage compensation based automatic voltage regulator having an AC chopper. The apparatus of claim 1,
And detecting a drop in the input voltage, turning on the first bypass switch of the bypass circuit and turning off the second bypass switch. The apparatus of claim 1,
And detecting an increase in the input voltage, turning off the first bypass switch of the bypass circuit and turning on the second bypass switch. The apparatus of claim 1,
A series voltage compensation based automatic voltage regulator having an AC chopper, wherein any two switches of the first to fourth switches of the AC chopper are turned on, and the remaining two switches are operated at a predetermined duty ratio. The apparatus of claim 1,
And a switching voltage change pattern after the dead time of the switch when the switching pattern of the switch driving signal for the switches is changed. The method of claim 1,
An AC chopper, characterized in that each of the automatic voltage regulator of claim 1 to compensate the input voltage of each phase to implement the voltage adjustment for the input voltage of each phase of the three-phase input voltage to implement a three-phase automatic voltage regulator A series voltage compensation based automatic voltage regulator.

Images