WO2016060319A1 - Reactive power compensation apparatus and reactive power compensation method - Google Patents

Reactive power compensation apparatus and reactive power compensation method Download PDF

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Publication number
WO2016060319A1
WO2016060319A1 PCT/KR2014/010658 KR2014010658W WO2016060319A1 WO 2016060319 A1 WO2016060319 A1 WO 2016060319A1 KR 2014010658 W KR2014010658 W KR 2014010658W WO 2016060319 A1 WO2016060319 A1 WO 2016060319A1
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Prior art keywords
compensation
power
phase
supply path
power supply
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PCT/KR2014/010658
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French (fr)
Korean (ko)
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김정우
정진영
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창명제어기술(주)
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/12—Circuit arrangements for ac mains or ac distribution networks for adjusting voltage in ac networks by changing a characteristic of the network load
    • H02J3/16—Circuit arrangements for ac mains or ac distribution networks for adjusting voltage in ac networks by changing a characteristic of the network load by adjustment of reactive power
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05F—SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
    • G05F1/00—Automatic systems in which deviations of an electric quantity from one or more predetermined values are detected at the output of the system and fed back to a device within the system to restore the detected quantity to its predetermined value or values, i.e. retroactive systems
    • G05F1/70—Regulating power factor; Regulating reactive current or power
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06Q—INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES; SYSTEMS OR METHODS SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES, NOT OTHERWISE PROVIDED FOR
    • G06Q50/00—Information and communication technology [ICT] specially adapted for implementation of business processes of specific business sectors, e.g. utilities or tourism
    • G06Q50/06—Energy or water supply
    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B25/00—Alarm systems in which the location of the alarm condition is signalled to a central station, e.g. fire or police telegraphic systems
    • G08B25/01—Alarm systems in which the location of the alarm condition is signalled to a central station, e.g. fire or police telegraphic systems characterised by the transmission medium
    • G08B25/06—Alarm systems in which the location of the alarm condition is signalled to a central station, e.g. fire or police telegraphic systems characterised by the transmission medium using power transmission lines
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
    • Y02B70/30—Systems integrating technologies related to power network operation and communication or information technologies for improving the carbon footprint of the management of residential or tertiary loads, i.e. smart grids as climate change mitigation technology in the buildings sector, including also the last stages of power distribution and the control, monitoring or operating management systems at local level
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
    • Y02E40/10—Flexible AC transmission systems [FACTS]
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
    • Y02E40/30—Reactive power compensation
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P80/00—Climate change mitigation technologies for sector-wide applications
    • Y02P80/10—Efficient use of energy, e.g. using compressed air or pressurized fluid as energy carrier

Definitions

  • the present invention relates to a reactive power compensation device and a compensation method capable of compensating for when ground reactive power occurs due to a power factor drop in a power supply system, and particularly, by using a semiconductor switch having a fast operating speed by monitoring and measuring the power factor in real time C. It relates to a power compensation device and a compensation method.
  • the reactive power refers to an reactive component that lowers power efficiency only when AC power is applied to a load such as an induction motor including a reactance component so that a current that is later than the voltage flows to perform no power transmission.
  • the reactive power is returned to the power supply side and unnecessarily increases the amount of current flowing through the wire to generate heat loss, thereby increasing the capacity of the transformer switchboard. have.
  • reactive power causes heat as well as electromagnetic resonance on the power transmission path, causing a problem of increasing electromagnetic pollution.
  • FIG. 1 shows a three-phase motor control structure according to the prior art.
  • the control module between the three-phase power source and the three-phase motor is a starter circuit, and performs a predetermined control operation only when the three-phase motor is started. I just delivered it to a three-phase motor. In this case, even if a power factor drop in the three-phase power source occurs during the normal driving of the three-phase motor, no countermeasures can be taken, and a decrease in efficiency due to reactive power is inevitable.
  • industrial sites use power factor control devices that maximize active power, minimize reactive power, and have a power factor close to one.
  • Such a power factor regulator is generally composed of a reactor, a capacitor, a magnet switch, and a discharge coil between a load such as an input power source and a motor.
  • the power factor adjuster configured as described above has a problem in that power factor compensation for load fluctuations is not sufficient.
  • the fastening capacitor is used to improve the power factor, but this fixed capacitor is always in the state of high efficiency and does not improve the power factor, and switching is performed after 6 to 12 cycles of the power sine wave when the power is turned on or off. It was not satisfactory also in speed. This makes it impossible to achieve optimum load efficiency, especially in the case of frequent startups such as motor loads and heavy load fluctuations.
  • the present invention is to provide a reactive power compensation device and / or compensation method that can effectively prevent the generation of reactive power at low cost.
  • Another object of the present invention is to provide a reactive power compensation device and / or a compensation method capable of quickly compensating reactive power in an environment requiring fast action such as driving a motor.
  • the sensing unit for sensing the power factor of the three-phase power supply path;
  • An invalid compensation switching unit configured to compensate for reactive power in power supplied to the three-phase power supply path by adjusting the number of capacitors connected to each phase of the three-phase power supply path;
  • a switching controller configured to control a switching operation of the invalid compensation switching unit according to the detected power factor.
  • the invalid compensation switching unit may include a compensation capacitor connected between a power supply path of each phase and a neutral wire; A semiconductor switch for switching a connection of the compensation capacitor; And a unit adjustment module having a harmonic attenuation reactor connected in series with the semiconductor switch.
  • the sensing unit senses the voltage and the current of the R, S, and T phase power supply paths, respectively, and the switching controller determines whether or not the reactive power generation of each phase from the voltage and current of the respective phases. Can be.
  • the switching controller may be configured to control the instantaneous power to compensate the reactive power for the neutral point only for the specific phase whose power factor is lowered.
  • the switching controller may switch the semiconductor switch when the voltage or current of each phase transmitted from the sensing unit reaches zero point.
  • the compensation capacitor of each unit adjustment module may have a different capacitance value.
  • the compensation capacitor of each unit adjustment module may have a capacitance value that is doubled.
  • a reactive power compensation method includes: monitoring a voltage and a current of a power supply path; Calculating a power factor of the current and voltage; If the power factor is not 1.0, determining a compensation capacitance; Selecting capacitors to connect to the power supply path according to the determined compensation capacitance; And coupling the selected capacitors to the power supply path.
  • the determining of the compensation capacitance may be performed by determining a compensation capacitance corresponding to an absolute value of the power factor other than 1.0.
  • the determining of the compensation capacitance may be performed by calculating a reduced power factor with the monitored cumulative values for the power factor of the monitoring step and determining a compensation capacitance corresponding to the calculated power factor value.
  • the selecting of capacitors to be connected to the power supply path may be performed by referring to a table consisting of on / off combinations of switches connecting capacitors to which one field gives a capacitance value and another field gives a capacitance value. Can be.
  • the implementation of the reactive power compensation device or the compensation method of the present invention having the above-described configuration has an advantage of effectively preventing the generation of reactive power at low cost.
  • the present invention has the advantage of being able to quickly compensate for the reactive power in real time in an environment requiring a quick action, such as a motor drive. That is, in particular, when applied to a motor drive with a large number of start-ups or frequent load fluctuations, there is an advantage in that the efficiency of the motor can be maximized instantaneously with an excellent power saving effect.
  • 1 is a block diagram showing a connection diagram of a general load.
  • FIG. 2 is a circuit diagram showing the structure of a reactive power compensation device according to an embodiment of the present invention.
  • FIG. 3 is a waveform diagram showing waveforms of voltage and current on a power supply path for explaining the improved switching control method.
  • FIG. 4 is a flowchart illustrating a reactive power compensation method according to another embodiment of the present invention.
  • FIG. 5 is a flowchart illustrating a reactive power compensation method according to another embodiment of the present invention.
  • first and second may be used to describe various components, but the components may not be limited by the terms. The terms are only for the purpose of distinguishing one component from another.
  • first component may be referred to as the second component, and similarly, the second component may also be referred to as the first component.
  • a component When a component is referred to as being connected or connected to another component, it may be understood that the component may be directly connected to or connected to the other component, but there may be other components in between. .
  • the present invention compensates for reactive power so that apparent power is converted into active power so that the load can achieve optimal efficiency by detecting and controlling the voltage phase, current phase, and current value of the load. Giving device. This ultimately reduces electricity by reducing the input current and inducing the load to operate at optimal efficiency.
  • FIG. 2 is a circuit diagram illustrating a structure of a reactive power compensation device according to an embodiment of the present invention.
  • the sensing unit 110 for detecting the power factor of the three-phase power supply path;
  • An invalid compensation switching unit (140) for compensating reactive power in power supplied to the three-phase power supply path by adjusting the number of capacitors connected to each phase of the three-phase power supply path;
  • a switching controller 160 that controls the switching operation of the invalid compensation switching unit according to the detected power factor.
  • the invalid compensation switching unit 140 may include two or more unit adjustment modules, and each unit adjustment module may include a compensation capacitor C1 ⁇ connected between a neutral supply line and a power supply path of each phase of the load 10. C15); A semiconductor switch S1 to S15 for switching the connection of the compensation capacitors C1 to C15; And harmonic attenuation reactors L1 to L15 connected in series to the semiconductor switches S1 to S15.
  • the illustrated reactive power compensation device is applied to a three-phase AC power environment, and it is natural that the idea of the present invention can be applied to a single-phase AC environment.
  • the reactive power of the AC power is generated from the power factor decrease due to the phase difference between the voltage and the current.
  • the reactive power of the AC power may be calculated using the phase difference value, and the detection unit 110 may sense the voltage and the current on the power supply path. Means may be included.
  • the sensing unit 110 may sense only the voltage and current of one of the R, S, and T phases, but when the three-phase balancing is unstable, R, S, and T The voltage and current of both phases can be sensed.
  • a simple voltage detection node can be implemented as the voltage sensing means
  • a current transformer can be implemented as the current sensing means.
  • the reactive power compensating device of this embodiment adjusts the power factor in such a manner as to add a suitable capacitance component between the power supply path and the neutral line of each phase of the load 10 according to the measured power factor.
  • a triac is applied to the semiconductor switches S1 to S15 in the drawing, other semiconductor switch elements such as a thyristor, a power MOS transistor, a power junction transistor, and the like may be applied.
  • the compensation capacitors C1 to C15 of each unit adjustment module have different capacitance values, and more specifically, have capacitance values that increase by twice. In another implementation, the compensation capacitors of each unit adjustment module may have the same capacitance value.
  • the capacitance applying operation is smoothed between the power supply path and the neutral line of each phase by the semiconductor switches S1 to S15.
  • the switching harmonics caused by the adjustment are reduced, and smaller harmonic attenuation reactors L1 to L15 can be applied.
  • changing the capacitance value requires a smaller number of switching to reduce harmonic generation.
  • five compensation capacitors C1, C4, C7, C10, and C13 (C2, C5, C8, C11, C14) (C3, C6) between the power supply path and the neutral line of each phase , C9, C12, C15 may be connected.
  • the capacitance values of the five compensation capacitors C1, C4, C7, C10, and C13 (C2, C5, C8, C11, and C14) (C3, C6, C9, C12, and C15) have a double relationship with each other.
  • the capacitance value of the smallest compensation capacitor is U
  • the other four compensation capacitors have capacitance values of 2U, 4U, 8U, and 14U, respectively.
  • the switching controller 160 controls the invalid compensation switching unit 140 to adjust the power factor with respect to the power factor value measured by the sensing unit 110, and corresponds to a power factor measured according to a predetermined rule.
  • the power factor may be adjusted by assigning a capacitance value or by changing the capacitance value in a feedback control manner.
  • the information on the predetermined rule may be stored in a storage space inside the switching controller 160 or another separate storage means.
  • one field may store a table of power factor values, a capacitance value to be given by another field, and on / off combinations of switches to which another field is assigned to a capacitance value.
  • an increase (or decrease) of a capacitance value to be provided between the power supply path and the neutral line of each phase may be defined.
  • the prescribed increment may be stored in a storage space inside the switching controller 160 or another separate storage means.
  • the operation of the load 10 to be driven may be maximized to maximize electricity savings and efficiency. That is, the switching controller 160 may instantaneously control the power factor to be close to 1.0 using the semiconductor switches S1 to S15 to increase efficiency.
  • the detector 110 and the switching controller 160 may detect the power factor for each of the R, S, and T phases.
  • the switching controller 160 may instantaneously control to compensate reactive power for the neutral point only for a specific phase having a reduced power factor.
  • the switching controller 160 may sequentially control to compensate reactive power of each phase with respect to the neutral point.
  • instantaneous means that the switching / control is instantaneously performed. When switching or control is performed within one cycle of the square wave of the AC power from the time when the cause occurs, it may be regarded as instantaneous.
  • the turn-on time when a driving pulse is applied to a gate is very short compared to one cycle of an AC power source having a general frequency, and thus instantaneous control is possible as described above.
  • Each illustrated unit adjustment module includes a harmonic attenuation reactor connected in series with the semiconductor switch element in order to suppress harmonics generated during switching of the semiconductor switch element, but switching when the voltage and / or current is a large value is a large harmonic. Can be generated.
  • the reactive power compensation apparatus of the present embodiment can apply a more improved control method of switching the semiconductor switch A when the power sine wave becomes zero.
  • FIG. 3 illustrates waveforms of voltages and currents on a power supply path for explaining an improved switching control method of performing switching at the zero point
  • FIG. 4 is a flowchart illustrating the improved switching control method.
  • FIG. 3A is a voltage and current of AC power in a normal power supply environment
  • FIG. 3B is a voltage and current of AC power supplied when reactive power occurs (that is, power factor drop occurs). to be. It can be seen from FIG. 3 (b) that a delay occurs in the current waveform compared to the voltage waveform.
  • the harmonic attenuation reactors L1 to L15 connected in series with the semiconductor switch have a greater blocking effect on voltage than current.
  • the switching control unit may instantaneously control to compensate for reactive power with respect to the neutral point even in a specific phase in which the power factor of the three phases is lowered.
  • the reactive power compensation method according to the improved embodiment shown in FIG. 4 is as follows.
  • the power factor is calculated using the voltage and the current (S120).
  • step S110 If the calculated power factor is greater than 0.99 and less than or equal to 1.0, the process returns to step S110 again to monitor the voltage and current of the power supply path, and calculates the power factor of step S120 (S130).
  • the compensation capacitance is determined (S140).
  • a capacitor to be connected to the power supply path is selected according to the determined compensation capacitance.
  • the semiconductor switch When the voltage reaches 0 (S160), the semiconductor switch is turned on to connect the selected compensation capacitor (S170).
  • the illustrated reactive power compensation method may be performed by the switching controller 160 of the reactive power compensation device of FIG. 2.
  • the monitoring of the voltage and current (S110) may be performed by periodically receiving the detection value of the sensing unit 110 of FIG. 2.
  • the steps S130 and S160 may be performed by checking the periodically input current value or voltage value.
  • the determining of the compensation capacitance may be performed by simply determining the compensation capacitance corresponding to the absolute value of the voltage, or calculating the amount of reactive power (ie, power factor drop) based on the voltage / current monitored accumulation values. And determining a compensation capacitance corresponding to the calculated value.
  • an absolute value of a voltage when one field stored in a storage space inside the switching controller 160 or another separate storage means is 0 current, and another field is provided. This may be performed by referring to a table composed of capacitance values to be performed.
  • the determining of the compensation capacitance (S140) may be stored in a storage space inside the switching controller 160 or another separate storage means, and defined according to the absolute voltage value at the zero current. It can be performed using an increase (or decrease) in the capacitance value to be provided between the power supply path and the neutral line of each phase.
  • the determining of the compensation capacitance may include a power factor value at which one field is stored in a storage space inside the switching controller 160 or another separate storage means, and a capacitance value to be given by another field. It can be performed by referring to the table.
  • the determining of the compensation capacitance (S140) may be performed in the storage space inside the switching controller 160 or another separate storage means, and the respective phases defined according to the reduced power factor value. It may be performed using an increase (or decrease) in the capacitance value to be provided between the power supply path and the neutral line.
  • Selecting capacitors to be connected to the power supply path (S150) may be stored in a storage space inside the switching control unit 160 or another separate storage means, and a capacitance value to be given by one field and a capacitance value by another field. It can be performed by referring to a table consisting of on / off combinations of switches to be given.
  • Connecting the selected capacitors to the power supply path (S170) may be performed in a manner in which the switching controller 160 of FIG. 2 controls on / off semiconductor switches of the invalid compensation switching unit 140.
  • the reactive power compensation operation is performed at c2 and c4 in FIG. 3B.
  • the reactive power compensation operation is performed only at the c2 time point or the c4 time point.
  • the reactive power compensation method shown in FIG. 4 is performed on the supply path of single-phase AC power, on the supply path of all three-phase AC power, or independently for each R, S, T phase of three-phase AC power. Can be performed.

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Abstract

A reactive power compensation apparatus of the present invention comprises: a sensing unit for sensing the power factor of a three-phase power supply path; a reactive compensation switching unit for adjusting the number of capacitors coupled to each phase of the three-phase power supply path and for compensating reactive power of the power supplied to the three-phase power supply path; and a switching control unit for controlling a switching operation of the reactive compensation switching unit according to the sensed power factor, wherein the reactive compensation switching unit may comprise compensation capacitors connecting between the power supply paths of the respective phases and a neutral line; a semi-conductor switch for switching the connection of the compensation capacitors; and two or more unit control modules having a harmonic reduction reactor that is connected in series with the semi-conductor switch.

Description

무효 전력 보상 장치 및 무효 전력 보상 방법Reactive power compensation device and reactive power compensation method
본 발명은 전력 공급 계통에 역률 저하로 지상 무효 전력이 발생시 이를 보상할 수 있는 무효 전력 보상 장치 및 보상 방법에 관한 것으로, 특히 실시간 C로 역율을 감시, 측정하여 동작 속도가 빠른 반도체 스위치를 이용한 무효 전력 보상 장치 및 보상 방법에 관한 것이다.The present invention relates to a reactive power compensation device and a compensation method capable of compensating for when ground reactive power occurs due to a power factor drop in a power supply system, and particularly, by using a semiconductor switch having a fast operating speed by monitoring and measuring the power factor in real time C. It relates to a power compensation device and a compensation method.
일반적으로 무효전력이라 함은 리액턴스 성분을 포함하는 유도 전동기 등의 부하에 교류 전원을 인가했을 경우, 전압보다 늦은 전류가 흘러서 전력의 전송에 어떤 일도 하지 않는 전력효율만 떨어뜨리는 무효성분을 말한다.In general, the reactive power refers to an reactive component that lowers power efficiency only when AC power is applied to a load such as an induction motor including a reactance component so that a current that is later than the voltage flows to perform no power transmission.
이러한 무효전력은 전동기 등의 부하에서 동력으로 변환되어 소비되는 유효 전력과는 달리, 전원 측으로 되돌려지며 불필요하게 전선에 흐르는 전류량을 증가시켜 열손실을 발생시켜 변압기 배전반 등의 설비 용량을 증대시키는 문제점이 있다. 또한, 무효 전력은 전력 전송 경로 상에 열 뿐만 아니라 전자기적 공진을 일으켜 전자파 공해를 가중시키는 문제를 야기한다.Unlike the active power consumed by being converted into power from a load such as an electric motor, the reactive power is returned to the power supply side and unnecessarily increases the amount of current flowing through the wire to generate heat loss, thereby increasing the capacity of the transformer switchboard. have. In addition, reactive power causes heat as well as electromagnetic resonance on the power transmission path, causing a problem of increasing electromagnetic pollution.
도 1은 종래 기술에 의한 3상 모터 제어 구조를 도시한다. 1 shows a three-phase motor control structure according to the prior art.
도 1에서 3상 전원과 3상 모터 사이의 제어 모듈은 스타터 회로로서, 3상 모터의 기동시에만 소정의 제어 동작을 수행하며, 3상 모터의 일반적인 구동시에는 별다른 역할없이 3상 전원의 전력을 그대로 3상 모터로 전달할 뿐이었다. 이 경우, 3상 모터의 일반적인 구동시에 3상 전원에서의 역률 저하가 발생하여도, 대응조치를 취하지 못하여, 무효 전력으로 인한 효율 저하를 피할 수 없었다.In Figure 1, the control module between the three-phase power source and the three-phase motor is a starter circuit, and performs a predetermined control operation only when the three-phase motor is started. I just delivered it to a three-phase motor. In this case, even if a power factor drop in the three-phase power source occurs during the normal driving of the three-phase motor, no countermeasures can be taken, and a decrease in efficiency due to reactive power is inevitable.
이에 따라 각 산업 현장에서는 부하에 최대 전력을 공급하기 위해 유효전력을 최대로 하고, 무효전력을 최소로, 역률을 1에 가까운 값을 갖도록 하는 역률 조절 장치를 사용하고 있는 실정이다.Accordingly, in order to supply the maximum power to each load, industrial sites use power factor control devices that maximize active power, minimize reactive power, and have a power factor close to one.
이러한 역률 조정장치는 일반적으로 입력전원과 모터 등과 같은 부하 사이에 리액터, 커패시터, 마그네트 스위치, 방전 코일로 구성되어 있다. 그러나 이와 같이 구성된 역률 조정장치는 부하 변동에 대한 역률 보상을 충분히 하지 못하는 문제점을 가지고 있다.Such a power factor regulator is generally composed of a reactor, a capacitor, a magnet switch, and a discharge coil between a load such as an input power source and a motor. However, the power factor adjuster configured as described above has a problem in that power factor compensation for load fluctuations is not sufficient.
즉 역률 개선을 위하여 진상용 커패시터를 사용하고 있으나, 이 고정 커패시터는 항시 투입된 상태로 고 효율의 역률 개선이 되지 않으며, 전원의 on/off 조작 시 전원 정현파의 6~12 사이클 정도가 지난 후에 스위칭이 되는 등 속도에 있어서도 만족스럽지 못하였다. 이는 특히 모터 부하와 같은 기동이 잦고 부하 변동이 심한 경우에도 최적의 부하 효율을 달성할 수 없게 하였다.In other words, the fastening capacitor is used to improve the power factor, but this fixed capacitor is always in the state of high efficiency and does not improve the power factor, and switching is performed after 6 to 12 cycles of the power sine wave when the power is turned on or off. It was not satisfactory also in speed. This makes it impossible to achieve optimum load efficiency, especially in the case of frequent startups such as motor loads and heavy load fluctuations.
본 발명은 무효 전력의 발생을 저렴한 비용으로 효과적으로 방지할 수 있는 무효 전력 보상 장치 및/또는 보상 방법을 제공하고자 한다.The present invention is to provide a reactive power compensation device and / or compensation method that can effectively prevent the generation of reactive power at low cost.
또는, 본 발명은 모터 구동 등 빠른 조치가 필요한 환경에서 신속하게 무효 전력을 보상할 수 있는 무효 전력 보상 장치 및/또는 보상 방법을 제공하고자 한다.Another object of the present invention is to provide a reactive power compensation device and / or a compensation method capable of quickly compensating reactive power in an environment requiring fast action such as driving a motor.
본 발명의 일 측면에 따른 무효 전력 보상 장치는, 3상 전력 공급 경로의 역률을 감지하는 감지부; 상기 3상 전력 공급 경로의 각 상에 연결되는 커패시터들의 개수를 조절하여, 상기 3상 전력 공급 경로로 공급되는 전력 내 무효 전력을 보상하는 무효 보상 스위칭부; 및 상기 감지된 역률에 따라, 상기 무효 보상 스위칭부의 스위칭 동작을 제어하는 스위칭 제어부를 포함하되,Reactive power compensation device according to an aspect of the present invention, the sensing unit for sensing the power factor of the three-phase power supply path; An invalid compensation switching unit configured to compensate for reactive power in power supplied to the three-phase power supply path by adjusting the number of capacitors connected to each phase of the three-phase power supply path; And a switching controller configured to control a switching operation of the invalid compensation switching unit according to the detected power factor.
상기 무효 보상 스위칭부는, 상기 각 상의 전력 공급 경로와 중성선 사이에 연결되는 보상 커패시터; 상기 보상 커패시터의 연결을 스위칭하는 반도체 스위치; 및 상기 반도체 스위치에 직렬 연결되는 고조파 감쇄 리액터를 구비하는 단위 조정 모듈을 2개 이상 포함할 수 있다.The invalid compensation switching unit may include a compensation capacitor connected between a power supply path of each phase and a neutral wire; A semiconductor switch for switching a connection of the compensation capacitor; And a unit adjustment module having a harmonic attenuation reactor connected in series with the semiconductor switch.
여기서, 상기 감지부는, R, S, T 상 전력 공급 경로의 전압 및 전류를 각각 감지하며, 상기 스위칭 제어부는, 상기 각 상의 전압 및 전류로부터 각 상의 무효 전력 발생 여부 또는 정도를 순시적으로 판단할 수 있다.Here, the sensing unit senses the voltage and the current of the R, S, and T phase power supply paths, respectively, and the switching controller determines whether or not the reactive power generation of each phase from the voltage and current of the respective phases. Can be.
여기서, 상기 스위칭 제어부는, 역률이 떨어진 특정 상에 대해서만 중성점에 대한 무효 전력을 보상하도록 순시적으로 제어할 수 있다.Here, the switching controller may be configured to control the instantaneous power to compensate the reactive power for the neutral point only for the specific phase whose power factor is lowered.
여기서, 상기 스위칭 제어부는, 상기 감지부에서 전달받은 상기 각 상의 전압 또는 전류가 0점에 도달하였을 때, 상기 반도체 스위치를 스위칭할 수 있다.The switching controller may switch the semiconductor switch when the voltage or current of each phase transmitted from the sensing unit reaches zero point.
여기서, 상기 각 단위 조정 모듈의 보상 커패시터는, 서로 다른 커패시턴스 값을 가질 수 있다.Here, the compensation capacitor of each unit adjustment module may have a different capacitance value.
여기서, 각 단위 조정 모듈의 보상 커패시터는, 2배로 증가하는 커패시턴스 값을 가질 수 있다.Here, the compensation capacitor of each unit adjustment module may have a capacitance value that is doubled.
본 발명의 다른 측면에 따른 무효 전력 보상 방법은, 전력 공급 경로의 전압 및 전류를 모니터링하는 단계; 상기 전류와 전압의 역률을 계산하는 단계; 역률이 1.0이 아니면, 보상 커패시턴스를 결정하는 단계; 상기 결정된 보상 커패시턴스에 따라 상기 전력 공급 경로에 연결할 커패시터들을 선택하는 단계; 및 상기 선택된 커패시터들을 상기 전력 공급 경로에 연결하는 단계를 포함할 수 있다.According to another aspect of the present invention, a reactive power compensation method includes: monitoring a voltage and a current of a power supply path; Calculating a power factor of the current and voltage; If the power factor is not 1.0, determining a compensation capacitance; Selecting capacitors to connect to the power supply path according to the determined compensation capacitance; And coupling the selected capacitors to the power supply path.
여기서, 상기 보상 커패시턴스를 결정하는 단계는, 상기 역률이 1.0이 아닌 역률의 절대값에 대응하는 보상 커패시턴스를 결정하는 방식으로 수행될 수 있다.The determining of the compensation capacitance may be performed by determining a compensation capacitance corresponding to an absolute value of the power factor other than 1.0.
여기서, 상기 보상 커패시턴스를 결정하는 단계는, 상기 모니터링 단계의 역률에 대한 모니터링된 누적값들로 저하된 역률을 산정하고, 산정된 역률 값에 대응하는 보상 커패시턴스를 결정하는 방식으로 수행될 수 있다.Here, the determining of the compensation capacitance may be performed by calculating a reduced power factor with the monitored cumulative values for the power factor of the monitoring step and determining a compensation capacitance corresponding to the calculated power factor value.
여기서, 상기 전력 공급 경로에 연결할 커패시터들을 선택하는 단계는, 일 필드가 부여할 커패시턴스 값이고 다른 필드가 커패시턴스 값을 부여하는 커패시터들을 연결하는 스위치들의 on/off 조합들로 이루어진 테이블을 참조하여 수행될 수 있다.Here, the selecting of capacitors to be connected to the power supply path may be performed by referring to a table consisting of on / off combinations of switches connecting capacitors to which one field gives a capacitance value and another field gives a capacitance value. Can be.
상술한 구성의 본 발명의 무효 전력 보상 장치 또는 보상 방법을 실시하면 무효 전력의 발생을 저렴한 비용으로 효과적으로 방지할 수 있는 이점이 있다.The implementation of the reactive power compensation device or the compensation method of the present invention having the above-described configuration has an advantage of effectively preventing the generation of reactive power at low cost.
또는, 본 발명은 모터 구동 등 빠른 조치가 필요한 환경에서 실시간으로 신속하게 무효 전력을 보상할 수 있는 이점이 있다. 즉, 특히, 기동 횟수가 많거나, 부하의 순시 변동이 잦은 모터 구동에 적용하면 탁월한 전력 절감 효과와 함께 모터의 효율을 순시적으로 극대화시킬 수 있는 이점이 있다.Alternatively, the present invention has the advantage of being able to quickly compensate for the reactive power in real time in an environment requiring a quick action, such as a motor drive. That is, in particular, when applied to a motor drive with a large number of start-ups or frequent load fluctuations, there is an advantage in that the efficiency of the motor can be maximized instantaneously with an excellent power saving effect.
도 1은 일반적인 부하의 결선도를 도시한 블록도.1 is a block diagram showing a connection diagram of a general load.
도 2는 본 발명의 일 실시예에 따른 무효 전력 보상 장치의 구조를 도시한 회로도.2 is a circuit diagram showing the structure of a reactive power compensation device according to an embodiment of the present invention.
도 3은 상기 개선된 스위칭 제어 방법을 설명하기 위한 전원 공급 경로 상의 전압 및 전류의 파형을 나타낸 파형도.3 is a waveform diagram showing waveforms of voltage and current on a power supply path for explaining the improved switching control method.
도 4는 본 발명의 다른 실시예에 따른 무효 전력 보상 방법을 도시한 흐름도.4 is a flowchart illustrating a reactive power compensation method according to another embodiment of the present invention.
도 5는 본 발명의 또 다른 실시예에 따른 무효 전력 보상 방법을 도시한 흐름도.5 is a flowchart illustrating a reactive power compensation method according to another embodiment of the present invention.
이하, 본 발명의 실시를 위한 구체적인 실시예를 첨부된 도면들을 참조하여 설명한다. Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings.
본 발명을 설명함에 있어서 제 1, 제 2 등의 용어는 다양한 구성요소들을 설명하는데 사용될 수 있지만, 구성요소들은 용어들에 의해 한정되지 않을 수 있다. 용어들은 하나의 구성요소를 다른 구성요소로부터 구별하는 목적으로만 된다. 예를 들어, 본 발명의 권리 범위를 벗어나지 않으면서 제 1 구성요소는 제 2 구성요소로 명명될 수 있고, 유사하게 제 2 구성요소도 제 1 구성요소로 명명될 수 있다. In describing the present invention, terms such as first and second may be used to describe various components, but the components may not be limited by the terms. The terms are only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as the second component, and similarly, the second component may also be referred to as the first component.
어떤 구성요소가 다른 구성요소에 연결되어 있다거나 접속되어 있다고 언급되는 경우는, 그 다른 구성요소에 직접적으로 연결되어 있거나 또는 접속되어 있을 수도 있지만, 중간에 다른 구성요소가 존재할 수도 있다고 이해될 수 있다.When a component is referred to as being connected or connected to another component, it may be understood that the component may be directly connected to or connected to the other component, but there may be other components in between. .
본 명세서에서 사용한 용어는 단지 특정한 실시예를 설명하기 위해 사용된 것으로, 본 발명을 한정하려는 의도가 아니다. 단수의 표현은 문맥상 명백하게 다르게 뜻하지 않는 한, 복수의 표현을 포함할 수 있다. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Singular expressions may include plural expressions unless the context clearly indicates otherwise.
본 명세서에서, 포함하다 또는 구비하다 등의 용어는 명세서상에 기재된 특징, 숫자, 단계, 동작, 구성요소, 부품 또는 이들을 조합한 것이 존재함을 지정하려는 것으로서, 하나 또는 그 이상의 다른 특징들이나 숫자, 단계, 동작, 구성요소, 부품 또는 이들을 조합한 것들의 존재 또는 부가 가능성을 미리 배제하지 않는 것으로 이해될 수 있다. In this specification, the terms including or including are intended to designate that there exists a feature, a number, a step, an operation, a component, a part, or a combination thereof described in the specification, and one or more other features or numbers, It can be understood that it does not exclude in advance the possibility of the presence or addition of steps, actions, components, parts or combinations thereof.
또한, 도면에서의 요소들의 형상 및 크기 등은 보다 명확한 설명을 위해 과장될 수 있다. In addition, the shape and size of the elements in the drawings may be exaggerated for more clear description.
본 발명의 제안은 기존의 무효 전력 보상 장치와는 달리 부하의 전압 위상, 전류 위상 및 전류치를 검출, 제어하여 부하가 최적의 효율을 낼수 있도록, 피상 전력이 유효 전력으로 변환되도록 무효전력을 보상시켜 주는 장치이다. 이렇게 함으로서 궁극적으로 입력의 전류를 줄이고 부하가 최적의 효율 상태로 동작 되도록 유도하여 전기를 절감하는 방식이다. Unlike the conventional reactive power compensation device, the present invention compensates for reactive power so that apparent power is converted into active power so that the load can achieve optimal efficiency by detecting and controlling the voltage phase, current phase, and current value of the load. Giving device. This ultimately reduces electricity by reducing the input current and inducing the load to operate at optimal efficiency.
도 2는 본 발명의 일 실시예에 따른 무효 전력 보상 장치의 구조를 도시한 회로도이다.2 is a circuit diagram illustrating a structure of a reactive power compensation device according to an embodiment of the present invention.
도시한 실시예에 따른 무효 전력 보상 장치는, 3상 전력 공급 경로의 역률을 감지하는 감지부(110); 상기 3상 전력 공급 경로의 각 상에 연결되는 커패시터들의 개수를 조절하여, 상기 3상 전력 공급 경로로 공급되는 전력 내 무효 전력을 보상하는 무효 보상 스위칭부(140); 및 상기 감지된 역률에 따라, 상기 무효 보상 스위칭부의 스위칭 동작을 제어하는 스위칭 제어부(160)를 포함할 수 있다. Reactive power compensation apparatus according to the embodiment, the sensing unit 110 for detecting the power factor of the three-phase power supply path; An invalid compensation switching unit (140) for compensating reactive power in power supplied to the three-phase power supply path by adjusting the number of capacitors connected to each phase of the three-phase power supply path; And a switching controller 160 that controls the switching operation of the invalid compensation switching unit according to the detected power factor.
상기 무효 보상 스위칭부(140)는 2개 이상 또는 다수 개의 단위 조정 모듈들을 포함하며, 각 단위 조정 모듈은, 상기 부하(10)의 각 상의 전력 공급 경로와 중성선 사이에 연결되는 보상 커패시터(C1 ~ C15); 상기 보상 커패시터(C1 ~ C15)의 연결을 스위칭하는 반도체 스위치(S1 ~ S15); 및 상기 반도체 스위치(S1 ~ S15)에 직렬 연결되는 고조파 감쇄 리액터(L1 ~ L15)를 구비할 수 있다.The invalid compensation switching unit 140 may include two or more unit adjustment modules, and each unit adjustment module may include a compensation capacitor C1 ˜ connected between a neutral supply line and a power supply path of each phase of the load 10. C15); A semiconductor switch S1 to S15 for switching the connection of the compensation capacitors C1 to C15; And harmonic attenuation reactors L1 to L15 connected in series to the semiconductor switches S1 to S15.
도시한 무효 전력 보상 장치는 3상 교류 전원 환경에 적용한 것이며, 단상 교류 환경에도 본 발명의 사상을 적용할 수 있음은 당연하다.The illustrated reactive power compensation device is applied to a three-phase AC power environment, and it is natural that the idea of the present invention can be applied to a single-phase AC environment.
교류 전력의 무효 전력은 전압 및 전류의 위상 차이로 인한 역률 저하로부터 발생하며, 상기 위상 차이값을 이용하여 산출할 수 있는 바, 상기 감지부(110)는 전원 공급 경로상의 전압 및 전류를 센싱하는 수단들을 포함할 수 있다.The reactive power of the AC power is generated from the power factor decrease due to the phase difference between the voltage and the current. The reactive power of the AC power may be calculated using the phase difference value, and the detection unit 110 may sense the voltage and the current on the power supply path. Means may be included.
전력 공급 환경의 3상 밸런싱이 확고한 경우, 상기 감지부(110)는 R, S, T 상들 중 하나의 상의 전압 및 전류만을 센싱하면 충분하나, 3상 밸런싱이 불안정한 경우에는, R, S, T 상 모두의 전압 및 전류를 센싱할 수 있다. 예컨대, 전압 센싱 수단으로서 단순한 전압 검출 노드를 구현할 수 있고, 전류 센싱 수단으로서 변류기를 구현할 수 있다.When the three-phase balancing of the power supply environment is firm, the sensing unit 110 may sense only the voltage and current of one of the R, S, and T phases, but when the three-phase balancing is unstable, R, S, and T The voltage and current of both phases can be sensed. For example, a simple voltage detection node can be implemented as the voltage sensing means, and a current transformer can be implemented as the current sensing means.
본 실시예의 무효 전력 보상 장치는, 측정된 역률에 따라, 부하(10)의 각 상의 전력 공급 경로와 중성선 사이에 적합한 커패시턴스 성분을 추가하는 방식으로 역률을 조정한다. The reactive power compensating device of this embodiment adjusts the power factor in such a manner as to add a suitable capacitance component between the power supply path and the neutral line of each phase of the load 10 according to the measured power factor.
도면에서 상기 반도체 스위치(S1 ~ S15)로 트라이액을 적용하였으나, 다른 구현에서는 사이리스터, 파워 MOS 트랜지스터, 파워 정션 트랜지스터 등 다른 반도체 스위치 소자를 적용할 수 있다.Although a triac is applied to the semiconductor switches S1 to S15 in the drawing, other semiconductor switch elements such as a thyristor, a power MOS transistor, a power junction transistor, and the like may be applied.
상기 실시예에서는 상기 각 단위 조정 모듈의 보상 커패시터(C1 ~ C15)는, 서로 다른 커패시턴스 값을 가지며, 보다 구체적으로 2배로 증가하는 커패시턴스 값을 가진다. 다른 구현에서는, 상기 각 단위 조정 모듈의 보상 커패시터들이 동일한 커패시턴스 값을 가질 수 있다.In the above embodiment, the compensation capacitors C1 to C15 of each unit adjustment module have different capacitance values, and more specifically, have capacitance values that increase by twice. In another implementation, the compensation capacitors of each unit adjustment module may have the same capacitance value.
2배로 증가하는 커패시턴스 값을 가지는 경우, 상기 반도체 스위치(S1 ~ S15)에 의해 선택된 커패시터들(C1 ~ C15)의 조합에 따라, 서로 다른 다양한 수치(예를 들어, 2n, 가지수, n: 자연수)의 커패시턴스 값을 각 상의 전력 공급 경로와 중성선 사이에 부여할 수 있는 이점이 있다.When the capacitance value is doubled, various values different from each other (for example, 2 n , number, n: The capacitance value of the natural number) can be given between the power supply path and the neutral line of each phase.
동일한 커패시턴스 값을 가지는 경우, 상기 반도체 스위치(S1 ~ S15)에 의한 각 상의 전력 공급 경로와 중성선 사이에 커패시턴스 부여 동작이 원활해지는 이점이 있다. 예컨대, 조정에 의한 스위칭 고조파가 작아져서 보다 작은 용량의 고조파 감쇄 리액터(L1 ~ L15)를 적용할 수 있다. 예컨대, 커패시턴스 값의 변경에 보다 작은 회수의 스위칭이 소요되어 고조파 발생을 저감할 수 있다.In the case of having the same capacitance value, there is an advantage in that the capacitance applying operation is smoothed between the power supply path and the neutral line of each phase by the semiconductor switches S1 to S15. For example, the switching harmonics caused by the adjustment are reduced, and smaller harmonic attenuation reactors L1 to L15 can be applied. For example, changing the capacitance value requires a smaller number of switching to reduce harmonic generation.
상기 무효 보상 스위칭부(140)에서, 각 상의 전력 공급 경로와 중성선 사이에 5개의 보상 커패시터들(C1,C4,C7,C10,C13)(C2,C5,C8,C11,C14)(C3,C6,C9,C12,C15)이 연결될 수 있다. 상기 5개의 보상 커패시터들(C1,C4,C7,C10,C13)(C2,C5,C8,C11,C14)(C3,C6,C9,C12,C15)의 커패시턴스 값을 서로 2배수의 관계를 가지도록 구현하면, 가장 작은 보상 커패시터의 커패시턴스 값을 U라고 하면, 다른 4개의 보상 커패시터들을 커패시턴스 값은 각각 2U 및 4U, 8U, 14U가 된다. 이 경우, 5개의 보상 커패시터들(C1,C4,C7,C10,C13)(C2,C5,C8,C11,C14)(C3,C6,C9,C12,C15)을 모두 선택할 때의 커패시턴스 값 31U 부터 1U까지 31단계로 커패시턴스 값을 부여하여, 역률 조정 및 무효 전력 보상을 수행할 수 있다.In the invalid compensation switching unit 140, five compensation capacitors C1, C4, C7, C10, and C13 (C2, C5, C8, C11, C14) (C3, C6) between the power supply path and the neutral line of each phase , C9, C12, C15 may be connected. The capacitance values of the five compensation capacitors C1, C4, C7, C10, and C13 (C2, C5, C8, C11, and C14) (C3, C6, C9, C12, and C15) have a double relationship with each other. In this implementation, if the capacitance value of the smallest compensation capacitor is U, the other four compensation capacitors have capacitance values of 2U, 4U, 8U, and 14U, respectively. In this case, from the capacitance value 31U when selecting all five compensation capacitors C1, C4, C7, C10, C13 (C2, C5, C8, C11, C14) (C3, C6, C9, C12, C15) By assigning a capacitance value in 31 steps up to 1U, power factor adjustment and reactive power compensation can be performed.
상기 스위칭 제어부(160)가, 상기 감지부(110)에서 측정된 역률 값에 대하여 역률을 조정하기 위하여 상기 무효 보상 스위칭부(140)를 제어하는 방안으로서, 미리 정해진 규정에 따라 측정된 역률에 부합하는 커패시턴스 값을 부여하거나, 또는 피드백 제어 방식으로 커패시턴스 값을 변경하여 역률을 조정할 수도 있다.The switching controller 160 controls the invalid compensation switching unit 140 to adjust the power factor with respect to the power factor value measured by the sensing unit 110, and corresponds to a power factor measured according to a predetermined rule. The power factor may be adjusted by assigning a capacitance value or by changing the capacitance value in a feedback control manner.
전자의 방안의 경우, 상기 스위칭 제어부(160) 내부의 저장 공간 또는 다른 별도의 저장 수단에, 상기 미리 정해진 규정에 대한 정보를 저장할 수 있다. 예컨대, 일 필드가 역률값, 다른 필드가 부여할 커패시턴스 값, 또 다른 필드가 커패시턴스 값을 부여하는 스위치들의 on/off 조합들로 이루어진 테이블을 저장할 수 있다.In the former scheme, the information on the predetermined rule may be stored in a storage space inside the switching controller 160 or another separate storage means. For example, one field may store a table of power factor values, a capacitance value to be given by another field, and on / off combinations of switches to which another field is assigned to a capacitance value.
후자의 경우, 상기 측정된 역률 값에 따라, 상기 각 상의 전력 공급 경로와 중성선 사이에 부여할 커패시턴스 값의 증가분(또는 감소분)을 규정할 수 있다. 이때, 규정된 증가분이 상기 스위칭 제어부(160) 내부의 저장 공간 또는 다른 별도의 저장 수단에 저장될 수 있다.In the latter case, according to the measured power factor value, an increase (or decrease) of a capacitance value to be provided between the power supply path and the neutral line of each phase may be defined. In this case, the prescribed increment may be stored in a storage space inside the switching controller 160 or another separate storage means.
구현에 따라, 상기 스위칭 제어부(160)의 상기 무효 보상 스위칭부(140)에 대한 역률 조정에 따라, 구동하려는 부하(10)의 동작을 극대화시켜, 전기 절감 및 효율을 최대화할 수 있다. 즉, 상기 스위칭 제어부(160)는, 효율을 높이기 위하여 역률을 1.0에 가깝게 반도체 스위치(S1 ~ S15)를 이용하여 순시 제어할 수 있다. In some implementations, according to the power factor adjustment of the invalid compensation switching unit 140 of the switching controller 160, the operation of the load 10 to be driven may be maximized to maximize electricity savings and efficiency. That is, the switching controller 160 may instantaneously control the power factor to be close to 1.0 using the semiconductor switches S1 to S15 to increase efficiency.
3상 밸런싱이 불안정한 환경에서 사용되는 구현의 경우, 상기 감지부(110) 및 상기 스위칭 제어부(160)는 각 R, S, T 상 마다의 역률을 검출할 수 있다. 상기 스위칭 제어부(160)는 역률이 떨어진 특정 상에 대해서만 중성점에 대한 무효 전력을 보상하도록 순시적으로 제어할 수 있다. 또는, 상기 스위칭 제어부(160)는 중성점에 대한 각 상의 무효 전력을 보상하도록 순차적으로 제어할 수 있다. 여기서, 순시적이라 함은 순간적으로 스위칭/제어가 수행되는 것을 의미하는데, 원인이 발생된 시점부터 교류 전원의 구형파의 1주기 이내로 스위칭 또는 제어가 수행되면 순시적이라고 볼 수 있다. In an implementation used in an environment in which three-phase balancing is unstable, the detector 110 and the switching controller 160 may detect the power factor for each of the R, S, and T phases. The switching controller 160 may instantaneously control to compensate reactive power for the neutral point only for a specific phase having a reduced power factor. Alternatively, the switching controller 160 may sequentially control to compensate reactive power of each phase with respect to the neutral point. Here, instantaneous means that the switching / control is instantaneously performed. When switching or control is performed within one cycle of the square wave of the AC power from the time when the cause occurs, it may be regarded as instantaneous.
트라이액 같은 반도체 스위치 소자는 게이트에 구동 펄스가 가해졌을 때 턴온되는 시간이 일반적인 주파수의 교류 전원의 1주기에 비하여 매우 짧아서, 상술한 바와 같이 순시적 제어가 가능하게 된다.In a semiconductor switch element such as a triac, the turn-on time when a driving pulse is applied to a gate is very short compared to one cycle of an AC power source having a general frequency, and thus instantaneous control is possible as described above.
도시한 각 단위 조정 모듈은, 반도체 스위치 소자의 스위칭시에 발생되는 고조파를 억제하기 위하여 상기 반도체 스위치 소자와 직렬 연결된 고조파 감쇄 리액터를 구비하지만, 전압 및/또는 전류가 큰 값일 때 스위칭하는 것은 큰 고조파를 발생시킬 수 있다.Each illustrated unit adjustment module includes a harmonic attenuation reactor connected in series with the semiconductor switch element in order to suppress harmonics generated during switching of the semiconductor switch element, but switching when the voltage and / or current is a large value is a large harmonic. Can be generated.
이러한 이유로 본 실시예의 무효 전력 보상 장치는, 전력 정현파가 0이 된 시점에 상기 반도체 스위치()를 스위칭하는 보다 개선된 제어 방법을 적용할 수 있다.For this reason, the reactive power compensation apparatus of the present embodiment can apply a more improved control method of switching the semiconductor switch A when the power sine wave becomes zero.
도 3은 상기 0 점에서 스위칭을 수행하는 개선된 스위칭 제어 방법을 설명하기 위한 전원 공급 경로 상의 전압 및 전류의 파형을 나타낸 것이며, 도 4는 상기 개선된 스위칭 제어 방법을 도시한 흐름도이다.FIG. 3 illustrates waveforms of voltages and currents on a power supply path for explaining an improved switching control method of performing switching at the zero point, and FIG. 4 is a flowchart illustrating the improved switching control method.
도 3의 (a)는 정상적인 전력 공급 환경에서의 교류 전력의 전압 및 전류이며, 도 3의 (b)는 무효 전력이 발생할 때(즉, 역률 저하가 발생)의 공급되는 교류 전원의 전압 및 전류이다. 도 3(b)에서 전압 파형에 비하여 전류 파형에 지연이 발생됨을 알 수 있다.FIG. 3A is a voltage and current of AC power in a normal power supply environment, and FIG. 3B is a voltage and current of AC power supplied when reactive power occurs (that is, power factor drop occurs). to be. It can be seen from FIG. 3 (b) that a delay occurs in the current waveform compared to the voltage waveform.
스위칭 동작에 의한 고조파 발생을 억제하기 위해서는, 공급되는 교류 전원의 전압 및 전류가 모두 0일 때 스위칭하는 것이 바람직하다. 그런데, 고조파가 발생되는 상황에서는 도 3의 (b)와 같이 공급되는 교류 전원의 전압 및 전류의 위상이 일치하지 않아, 공급되는 교류 전원의 전압 및 전류가 모두 0인 시점이 발생하지 않는다. In order to suppress the generation of harmonics due to the switching operation, it is preferable to switch when the voltage and current of the supplied AC power supply are both zero. However, in the situation where harmonics are generated, the phase of the voltage and current of the supplied AC power supply do not coincide with each other as shown in FIG.
한편, 상기 반도체 스위치에 직렬 연결된 고조파 감쇄 리액터(L1 ~ L15)는 그 특성상 전류 보다 전압에 대한 차단 효과가 크다. 따라서, 비록 전압이 다소 존재하더라도 전류가 0에 가까운 시점에 상기 반도체 스위치를 스위칭하는 것이 유리하다. 즉, 도 3의 (b)에서의 c1, c2, c3, c4 시점들 중 c2 시점이나 c4 시점에서 스위칭을 수행하는 것은 불리하다. 또는 c1과 c3 사이의 기간 중 c2에 가까운 시점이나, c3와 c4 사이의 기간 중 c4에 가까운 시점에 스위칭을 하면 불리하다.On the other hand, the harmonic attenuation reactors L1 to L15 connected in series with the semiconductor switch have a greater blocking effect on voltage than current. Thus, it is advantageous to switch the semiconductor switch at a time when the current is close to zero even if the voltage is somewhat present. That is, it is disadvantageous to perform switching at a c2 time point or a c4 time point among the c1, c2, c3, and c4 time points in FIG. 3B. Alternatively, it is disadvantageous to switch at a time close to c2 during the period between c1 and c3, or a time close to c4 during the period between c3 and c4.
또한, 상기 스위칭 제어부는, 3상 중 역률이 저하된 특정 상에 대해서도 중성점에 대한 무효 전력을 보상하도록 순시적으로 제어할 수 있다.In addition, the switching control unit may instantaneously control to compensate for reactive power with respect to the neutral point even in a specific phase in which the power factor of the three phases is lowered.
도 4에 도시한 개선된 실시예에 따른 무효 전력 보상 방법은 다음과 같다. The reactive power compensation method according to the improved embodiment shown in FIG. 4 is as follows.
먼저 전력 공급 경로의 전압 및 전류를 모니터링한다(S110).First, the voltage and current of the power supply path are monitored (S110).
그리고, 전압 및 전류를 이용하여 역률을 계산한다(S120).Then, the power factor is calculated using the voltage and the current (S120).
계산된 역률이 0.99 를 초과하고 1.0 이하이면 다시 S110 단계로 돌아가서 전력 공급 경로의 전압 및 전류를 모니터링하고, S120 단계의 역률을 계산한다(S130).If the calculated power factor is greater than 0.99 and less than or equal to 1.0, the process returns to step S110 again to monitor the voltage and current of the power supply path, and calculates the power factor of step S120 (S130).
계산된 역률이 0.99 미만이거나 1.0을 초과하면, 보상 커패시턴스를 결정한다(S140). If the calculated power factor is less than 0.99 or more than 1.0, the compensation capacitance is determined (S140).
그리고, 결정된 보상 커패시턴스에 따라 전력 공급 경로에 연결할 커패시터(capacitor)를 선택한다(S150). In operation S150, a capacitor to be connected to the power supply path is selected according to the determined compensation capacitance.
그리고, 전압이 0이 되면(S160), 선택된 보상 커패시터를 연결하기 위하여 반도체 스위치를 ON 시킨다(S170).When the voltage reaches 0 (S160), the semiconductor switch is turned on to connect the selected compensation capacitor (S170).
도시한 무효 전력 보상 방법은 도 2의 무효 전력 보상 장치의 스위칭 제어부(160)에 의해 수행될 수 있다. 상기 전압 및 전류를 모니터링하는 단계(S110)는 도 2의 감지부(110)의 감지값을 주기적으로 입력받는 방식으로 수행될 수 있다. 상기 S130 단계 및 S160 단계는 상기 주기적으로 입력받은 전류값 또는 전압값을 확인하는 방식으로 수행될 수 있다.The illustrated reactive power compensation method may be performed by the switching controller 160 of the reactive power compensation device of FIG. 2. The monitoring of the voltage and current (S110) may be performed by periodically receiving the detection value of the sensing unit 110 of FIG. 2. The steps S130 and S160 may be performed by checking the periodically input current value or voltage value.
상기 보상 커패시턴스를 결정하는 단계(S140)는, 단순히 전압의 절대값에 대응하는 보상 커패시턴스를 결정하는 방식으로 수행되거나, 전압/전류 모니터링된 누적값들로 무효 전력 정도(즉, 역률 저하)를 산정하고, 산정된 값에 대응하는 보상 커패시턴스를 결정하는 방식으로 수행될 수 있다. The determining of the compensation capacitance (S140) may be performed by simply determining the compensation capacitance corresponding to the absolute value of the voltage, or calculating the amount of reactive power (ie, power factor drop) based on the voltage / current monitored accumulation values. And determining a compensation capacitance corresponding to the calculated value.
전자의 경우, 상기 보상 커패시턴스를 결정하는 단계(S140)는, 상기 스위칭 제어부(160) 내부의 저장 공간 또는 다른 별도의 저장 수단에 저장된 일 필드가 0전류일 때의 전압 절대값, 다른 필드가 부여할 커패시턴스 값으로 이루어진 테이블을 참조하여 수행될 수 있다. In the former case, in the determining of the compensation capacitance (S140), an absolute value of a voltage when one field stored in a storage space inside the switching controller 160 or another separate storage means is 0 current, and another field is provided. This may be performed by referring to a table composed of capacitance values to be performed.
또는, 전자의 경우, 상기 보상 커패시턴스를 결정하는 단계(S140)는, 상기 스위칭 제어부(160) 내부의 저장 공간 또는 다른 별도의 저장 수단에 저장되며, 상기 0전류일 때의 전압 절대값에 따라 규정되는 상기 각 상의 전력 공급 경로와 중성선 사이에 부여할 커패시턴스 값의 증가분(또는 감소분)을 이용하여 수행될 수 있다.Alternatively, in the former case, the determining of the compensation capacitance (S140) may be stored in a storage space inside the switching controller 160 or another separate storage means, and defined according to the absolute voltage value at the zero current. It can be performed using an increase (or decrease) in the capacitance value to be provided between the power supply path and the neutral line of each phase.
후자의 경우, 상기 보상 커패시턴스를 결정하는 단계(S140)는, 상기 스위칭 제어부(160) 내부의 저장 공간 또는 다른 별도의 저장 수단에 저장된 일 필드가 저하된 역률값, 다른 필드가 부여할 커패시턴스 값으로 이루어진 테이블을 참조하여 수행될 수 있다. In the latter case, the determining of the compensation capacitance (S140) may include a power factor value at which one field is stored in a storage space inside the switching controller 160 or another separate storage means, and a capacitance value to be given by another field. It can be performed by referring to the table.
또는, 후자의 경우, 상기 보상 커패시턴스를 결정하는 단계(S140)는, 상기 스위칭 제어부(160) 내부의 저장 공간 또는 다른 별도의 저장 수단에 저장되며, 상기 저하된 역률 값에 따라 규정되는 상기 각 상의 전력 공급 경로와 중성선 사이에 부여할 커패시턴스 값의 증가분(또는 감소분)을 이용하여 수행될 수 있다.Alternatively, in the latter case, the determining of the compensation capacitance (S140) may be performed in the storage space inside the switching controller 160 or another separate storage means, and the respective phases defined according to the reduced power factor value. It may be performed using an increase (or decrease) in the capacitance value to be provided between the power supply path and the neutral line.
상기 전력 공급 경로에 연결할 커패시터들을 선택하는 단계(S150)는, 상기 스위칭 제어부(160) 내부의 저장 공간 또는 다른 별도의 저장 수단에 저장되며, 일 필드가 부여할 커패시턴스 값이고 다른 필드가 커패시턴스 값을 부여하는 스위치들의 on/off 조합들로 이루어진 테이블을 참조하여 수행될 수 있다. Selecting capacitors to be connected to the power supply path (S150) may be stored in a storage space inside the switching control unit 160 or another separate storage means, and a capacitance value to be given by one field and a capacitance value by another field. It can be performed by referring to a table consisting of on / off combinations of switches to be given.
상기 선택된 커패시터들을 상기 전력 공급 경로에 연결하는 단계(S170)는, 도 2의 스위칭 제어부(160)가 무효 보상 스위칭부(140)의 반도체 스위치들을 on/off 제어하는 방식으로 수행될 수 있다.Connecting the selected capacitors to the power supply path (S170) may be performed in a manner in which the switching controller 160 of FIG. 2 controls on / off semiconductor switches of the invalid compensation switching unit 140.
도 4에 도시한 방식으로만 무효 전력 보상 방법을 수행하면, 도 3의 (b)에서 c2 시점 및 c4 시점에서 무효 전력 보상 동작이 수행된다. 그런데, 반도체 스위치 동작 후 이에 대한 효과를 확인하기 까지는 어느 정도 대기 시간이 필요한 것을 감안하면, c2 시점 또는 c4 시점 하나에서만 무효 전력 보상 동작이 수행되는 것이 유리할 수 있다. When the reactive power compensation method is performed only in the manner illustrated in FIG. 4, the reactive power compensation operation is performed at c2 and c4 in FIG. 3B. However, considering that a waiting time is required to determine the effects after the semiconductor switch operation, it may be advantageous that the reactive power compensation operation is performed only at the c2 time point or the c4 time point.
도 4에 도시한 무효 전력 보상 방법은, 단상 교류 전력의 공급 경로에 대하여 수행되거나, 전체 3상 교류 전력의 공급 경로에 대하여 수행되거나, 3상 교류의 각 R, S, T 상에 대하여 독립적으로 수행될 수 있다.The reactive power compensation method shown in FIG. 4 is performed on the supply path of single-phase AC power, on the supply path of all three-phase AC power, or independently for each R, S, T phase of three-phase AC power. Can be performed.
상기한 실시예는 그 설명을 위한 것이며, 그 제한을 위한 것이 아님을 주의하여야 한다. 또한, 본 발명의 기술분야의 통상의 전문가라면 본 발명의 기술사상의 범위에서 다양한 실시예가 가능함을 이해할 수 있을 것이다.It should be noted that the above embodiment is for the purpose of illustration and not for the purpose of limitation. In addition, those skilled in the art will understand that various embodiments are possible within the scope of the technical idea of the present invention.

Claims (10)

  1. 3상 전력 공급 경로의 역률을 감지하는 감지부;A detector for detecting a power factor of the three-phase power supply path;
    상기 3상 전력 공급 경로의 각 상에 연결되는 커패시터들의 개수를 조절하여, 상기 3상 전력 공급 경로로 공급되는 전력 내 무효 전력을 보상하는 무효 보상 스위칭부; 및 An invalid compensation switching unit configured to compensate for reactive power in power supplied to the three-phase power supply path by adjusting the number of capacitors connected to each phase of the three-phase power supply path; And
    상기 감지된 역률에 따라, 상기 무효 보상 스위칭부의 스위칭 동작을 제어하는 스위칭 제어부를 포함하되,According to the detected power factor, including a switching control unit for controlling the switching operation of the invalid compensation switching unit,
    상기 무효 보상 스위칭부는,The invalid compensation switching unit,
    상기 각 상의 전력 공급 경로와 중성선 사이에 연결되는 보상 커패시터;A compensation capacitor connected between the power supply path of each phase and a neutral wire;
    상기 보상 커패시터의 연결을 스위칭하는 반도체 스위치; 및A semiconductor switch for switching a connection of the compensation capacitor; And
    상기 반도체 스위치에 직렬 연결되는 고조파 감쇄 리액터를 구비하는 단위 조정 모듈을 2개 이상 포함하는 것을 특징으로 하는 무효 전력 보상 장치.And at least two unit adjustment modules having a harmonic attenuation reactor connected in series with the semiconductor switch.
  2. 제 1 항에 있어서,The method of claim 1,
    상기 감지부는, R, S, T 상 전력 공급 경로의 전압 및 전류를 각각 감지하며,The detection unit, respectively, detects the voltage and current of the power supply path of the R, S, T phase,
    상기 스위칭 제어부는, 상기 각 상의 전압 및 전류로부터 각 상의 무효 전력 발생 여부 또는 정도를 순시적으로 판단하는 무효 전력 보상 장치.The switching control unit, the reactive power compensation device for instantaneously determining whether or not the reactive power generation of each phase from the voltage and current of each phase.
  3. 제 2 항에 있어서,The method of claim 2,
    상기 스위칭 제어부는, The switching control unit,
    역률이 떨어진 특정 상에 대해서만 중성점에 대한 무효 전력을 보상하도록 순시적으로 제어하는 무효 전력 보상 장치.A reactive power compensation device for instantaneous control to compensate reactive power for neutral point only for a particular phase whose power factor is lowered.
  4. 제 2 항에 있어서,The method of claim 2,
    상기 스위칭 제어부는,The switching control unit,
    상기 감지부에서 전달받은 상기 각 상의 전압 또는 전류가 0에 도달하였을 때, 상기 반도체 스위치를 스위칭하는 무효 전력 보상 장치.Reactive power compensation device for switching the semiconductor switch when the voltage or current of each phase received from the sensing unit reaches zero.
  5. 제 1 항에 있어서,The method of claim 1,
    상기 각 단위 조정 모듈의 보상 커패시터는, 서로 다른 커패시턴스 값을 가지는 무효 전력 보상 장치.The compensation capacitor of each unit adjustment module, the reactive power compensation device having a different capacitance value.
  6. 제 1 항에 있어서,The method of claim 1,
    각 단위 조정 모듈의 보상 커패시터는, 2배로 증가하는 커패시턴스 값을 가지는 무효 전력 보상 장치.The compensation capacitor of each unit adjustment module, the reactive power compensation device having a capacitance value that is doubled.
  7. 전력 공급 경로의 전압 및 전류를 모니터링하는 단계;Monitoring the voltage and current of the power supply path;
    상기 전류가 0일 때, 상기 전압이 0인지 여부를 판단하는 단계;Determining whether the voltage is zero when the current is zero;
    상기 전압이 0이 아니면, 보상 커패시턴스를 결정하는 단계;If the voltage is not zero, determining a compensation capacitance;
    상기 결정된 보상 커패시턴스에 따라 상기 전력 공급 경로에 연결할 커패시터들을 선택하는 단계; 및Selecting capacitors to connect to the power supply path according to the determined compensation capacitance; And
    상기 선택된 커패시터들을 상기 전력 공급 경로에 연결하는 단계Coupling the selected capacitors to the power supply path
    를 포함하는 무효 전력 보상 방법.Reactive power compensation method comprising a.
  8. 제 7 항에 있어서,The method of claim 7, wherein
    상기 보상 커패시턴스를 결정하는 단계는,Determining the compensation capacitance,
    상기 0이 아닌 전압의 절대값에 대응하는 보상 커패시턴스를 결정하는 방식으로 수행되는 무효 전력 보상 방법.And a compensation capacitance corresponding to the absolute value of the non-zero voltage.
  9. 제 7 항에 있어서,The method of claim 7, wherein
    상기 보상 커패시턴스를 결정하는 단계는,Determining the compensation capacitance,
    상기 모니터링 단계의 전압/전류에 대한 모니터링된 누적값들로 저하된 역률을 산정하고, 산정된 역률 값에 대응하는 보상 커패시턴스를 결정하는 방식으로 수행되는 무효 전력 보상 방법.And a reduced power factor from the monitored cumulative values for the voltage / current of the monitoring step, and determining a compensation capacitance corresponding to the calculated power factor value.
  10. 제 7 항에 있어서,The method of claim 7, wherein
    상기 전력 공급 경로에 연결할 커패시터들을 선택하는 단계는,Selecting capacitors to connect to the power supply path,
    일 필드가 부여할 커패시턴스 값이고 다른 필드가 커패시턴스 값을 부여하는 커패시터들을 연결하는 스위치들의 on/off 조합들로 이루어진 테이블을 참조하여 수행되는 무효 전력 보상 방법.A reactive power compensation method performed by referring to a table consisting of on / off combinations of switches connecting one of the capacitors to which one field gives a capacitance value and the other field gives a capacitance value.
PCT/KR2014/010658 2014-10-14 2014-11-07 Reactive power compensation apparatus and reactive power compensation method WO2016060319A1 (en)

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