WO2014077586A1 - Apparatus for converting power by means of fault-tolerant pwm switching and method for controlling same - Google Patents

Apparatus for converting power by means of fault-tolerant pwm switching and method for controlling same Download PDF

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WO2014077586A1
WO2014077586A1 PCT/KR2013/010302 KR2013010302W WO2014077586A1 WO 2014077586 A1 WO2014077586 A1 WO 2014077586A1 KR 2013010302 W KR2013010302 W KR 2013010302W WO 2014077586 A1 WO2014077586 A1 WO 2014077586A1
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output
switching
signal
inverter
unit
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PCT/KR2013/010302
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French (fr)
Korean (ko)
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김효성
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공주대학교 산학협력단
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Publication of WO2014077586A1 publication Critical patent/WO2014077586A1/en

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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/53—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M7/537—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters
    • H02M7/5387—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration
    • H02M7/53871—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration with automatic control of output voltage or current
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/32—Means for protecting converters other than automatic disconnection
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/32—Means for protecting converters other than automatic disconnection
    • H02M1/325—Means for protecting converters other than automatic disconnection with means for allowing continuous operation despite a fault, i.e. fault tolerant converters

Definitions

  • the present invention relates to a power conversion device by fault-tolerant PWM switching, in particular, in the power conversion device by PWM switching can detect the output current of the inverter and control the switching to it in the event of a load short circuit to protect the load stably.
  • the present invention relates to a power conversion device using a fault-tolerant PWM switching and a control method thereof.
  • a typical ESS (Energy Storage System) device charges when the demand for power is low on the grid side, and discharges power from the storage unit when the demand for power is high, and simultaneously supplies reactive power to the grid. It has a role of stabilizing power by instantaneous correction.
  • the ESS device includes a converter that receives grid-side power and converts the power into DC power, converts the received DC power into AC power, and transfers the power to the grid and the load, and a charging unit for supplying the DC power of the converter to the converter. It includes a PWM control unit for controlling the operation of each component.
  • Pulse Width Modulation (PWM) switching controls the magnitude of the output voltage or current according to the ratio of switching-on time within a given switching period. This is also called duty ratio control.
  • FIG. 1 is a view schematically showing the configuration of a power converter having a PWM inverter according to the prior art.
  • the control unit 150 sineically controls the output voltage of the single-phase inverter 120 and receives a voltage V Load across the output stage filter capacitor 130 to receive a reference sine wave V ref . Control as possible.
  • the control voltage (V Con ) is in the form of a sinusoidal waveform and compared with the comparison triangle wave (V Tri ) having the same frequency as the preset switching frequency in the PWM generator 160 PWM drive signal (G) of the inverter switch (120) 1 , G 2 , G 3 , G 4 )
  • the control voltage (V Con ) is greater than the comparison triangular wave (V Tri )
  • the PWM driving signals (G 1 , G 4 ) are in a high state and the corresponding switches (SW 1 , SW 4 ) are turned on.
  • the control voltage V Con is smaller than the comparative triangular wave V Tri , the PWM driving signals G 2 and G 3 are in a high state, thereby turning on the corresponding switches SW 2 and SW 3 .
  • FIG. 2 is a diagram illustrating an example of a PWM drive signal and an output voltage signal of a power converter having a conventional PWM inverter.
  • PWM driving signals G 1 and G 4 and G 2 and G 3 are paired and switched, and the inverter output voltage V inv is a DC link voltage. It has a value of + Vdc or -Vdc depending on the size of.
  • V Load the load output voltage smoothed through an LC filter
  • the technical problem to be solved by the present invention is to detect the output current of the inverter in the power conversion device by PWM switching power by the fault-tolerant PWM switching that can reliably protect the load by controlling the switching to the load short circuit accident It is to provide an inverter and a control method thereof.
  • a power conversion apparatus using fault tolerant PWM switching including: an inverter switching unit outputting a pulse signal corresponding to a magnitude of a DC link voltage; An LC filter unit for smoothing the voltage pulse signal output from the inverter switching unit and outputting the sinusoidal signal; A current sensor unit detecting a current output from the inverter switching unit; A PWM switching controller for comparing the absolute value of the current value detected by the current sensor unit with a preset current value and controlling the inverter switching unit according to an output value corresponding thereto; A control unit which detects the load voltage of the output stage of the LC filter unit and controls the load voltage to a reference sine wave voltage; And a PWM generator for receiving a sine wave voltage output from the controller and receiving a comparison triangle wave having a preset switching frequency to output a pulse width driving signal to the inverter switching unit.
  • the PWM switching control unit may include an absolute value converting unit converting the current value detected by the current sensor unit into an absolute value; A hysteresis comparator for comparing the current value converted into the absolute value with a preset upper limit current value and outputting a CL signal corresponding thereto, and an AND gate part for controlling the inverter switching unit according to the CL signal output from the hysteresis comparator.
  • the CL signal when the current value converted into an absolute value in the hysteresis comparator is smaller than a preset upper limit current value, the CL signal is output high, and when the current value converted into an absolute value is greater than the preset upper limit current value, CL The characteristic is that the signal is output low.
  • the AND gate unit turns on the inverter switching unit when the CL signal output from the hysteresis comparator is output high, and turns off the inverter switching unit when the CL signal is output low. It has that feature.
  • the current sensor unit is characterized in that it detects the current value across the output terminal of the inverter switching unit.
  • the switching frequency output from the PWM switching controller is characterized in that it is determined corresponding to the hysteresis width.
  • the narrower the hysteresis width, the higher the switching frequency, the wider the hysteresis width is characterized in that the switching frequency is reduced.
  • it is characterized in that it further comprises a voltage sensor unit for detecting the load voltage across the output of the LC filter unit.
  • control method of the power conversion apparatus by the fault-tolerant PWM switching includes the steps of detecting the current of the output terminal of the inverter switching unit and the voltage of the LC filter output stage; Converting the detected current value into an absolute value and comparing the current value with a preset current value to output a CL signal corresponding thereto; Controlling the switch on / off operation of the inverter switching unit by receiving the output CL signal; It characterized in that it comprises the step of adjusting the current and voltage of the inverter switching unit in accordance with the on / off control of the switching operation.
  • the CL signal in the step of outputting the CL signal, if the current value converted to the absolute value is smaller than the preset upper limit current value, the CL signal is outputted high and the current value converted to the absolute value is the preset upper limit current. If it is larger than the value, the CL signal is characterized in that it is output low.
  • the inverter switching unit is turned on when the CL signal is output high, and the inverter switching unit is turned off when the CL signal is output low.
  • the switching frequency is characterized in that the switching frequency increases when the hysteresis width is narrow corresponding to the hysteresis width, and the switching frequency decreases when the hysteresis width is wide.
  • the present invention it is possible to reliably protect the load by detecting the output current of the inverter in the power conversion device by PWM switching and controlling the switching to the load short circuit accident.
  • FIG. 1 is a view schematically showing the configuration of a power conversion apparatus by PWM switching according to the prior art.
  • FIG. 2 is a diagram illustrating a PWM driving signal and an output voltage of a power conversion device by PWM switching according to the related art.
  • Figure 3 is a diagram showing the configuration of a power conversion device by fault tolerance PWM switching according to the present invention.
  • Figure 4 is a view showing the output waveform according to the operating conditions of the power conversion device by fault tolerance PWM switching of the present invention.
  • 5 and 6 are diagrams showing the experimental waveform according to the load short operation of the inverter by the fault tolerance PWM switching of the present invention.
  • FIG. 7 is a diagram illustrating a load short operation test waveform of an inverter using fault tolerant PWM switching according to the present invention.
  • the power conversion device using fault tolerant PWM switching according to the present invention includes an inverter switching unit 320 outputting a pulse signal corresponding to the magnitude of the DC link voltage; An LC filter unit 340 for smoothing the voltage pulse signal output from the inverter switching unit 320 and outputting the sinusoidal signal; A current sensor unit 330 for detecting a current output from the inverter switching unit 320; A PWM switching controller 390 for comparing the absolute value of the current value detected by the current sensor unit 330 with a preset current value and controlling the inverter switching unit 320 according to an output value corresponding thereto; A control unit 370 for detecting the output voltage of the output stage of the LC filter unit 340 and controlling and outputting the control signal to a reference sine wave voltage; And a PWM generator 380 and the LC filter unit which receive a sine wave voltage output from the controller 370 and receive a comparison
  • the inverter switching unit 320 has at least one switching element, and has a full bridge structure consisting of four IGBT switching elements. Each of the four switching elements is connected with diodes in anti-parallel across the switching elements.
  • the inverter switching unit 320 may also have a half bridge structure or a push-pull structure.
  • the PWM switching controller 390 is connected to the connection portion of the gate electrode of the IGBT of the inverter switching unit 320.
  • the controller 370 controls the switching operation of the inverter switching unit 320 to control the size and shape of the output voltage of the load.
  • the control unit 370 selects the size and shape of the output voltage desired by the user and selects a voltage corresponding thereto. to provide.
  • the voltage sensor unit 350 detects the load voltage across the output of the LC filter unit 340, receives a reference voltage, controls a voltage corresponding thereto, and outputs the voltage to the PWM generator.
  • the current sensor unit 330 detects a load current of the inverter switching unit 320 and outputs the load current to the PWM switching control unit.
  • the PWM switching controller 390 includes an absolute value converter 391, a hysteresis comparator 392 and an AND gate 393.
  • the absolute value converter 391 converts the current value detected by the current sensor unit 330 into an absolute value
  • the hysteresis comparator 392 compares the current value converted into an absolute value with a preset upper limit current value. As a result, a corresponding CL signal is output.
  • the AND gate 393 controls the inverter switching unit 320 according to the CL signal output from the hysteresis comparator 392.
  • the hysteresis comparator 392 outputs the CL signal high when the current value converted to the absolute value is smaller than the preset upper limit current value, and the upper limit current to which the current value converted to the absolute value is preset. If it is larger than the value, the CL signal is output low.
  • the AND gate 393 turns on the inverter switching unit 320 when the CL signal output from the hysteresis comparator 392 is high, and outputs the CL signal low. When the inverter is switched off (OFF).
  • FIG. 4 is a view showing the output waveform according to the operating conditions of the power conversion device by the fault-tolerant PWM switching of the present invention.
  • the output signal CL of the fault tolerance PWM circuit is always in a high state, and the PWM driving signals G 1 , G 2 , G 3 , and G 4 of the inverter switching unit are connected to the AND gate. After passing through, operate the power conversion switch normally to generate inverter output voltage ( v inv ).
  • the difference between the inverter output voltage ( v inv ) and the load voltage ( v Load ) is applied across the filter inductor, and the inverter output current ( i inv ) is centered on a predetermined average value depending on the magnitude and polarity of the voltage applied across the filter inductor. Rise and fall repeatedly.
  • the load voltage ( v Load ) becomes almost zero as in (b), so that the voltage applied to the filter inductor increases to increase the inverter output current ( i inv ).
  • the output signal CL of the fault-tolerant PWM circuit immediately becomes high and the AND gate opens to open the PWM of the inverter switch. Passes all driving signals G 1 , G 2 , G 3 , and G 4 . At this time, if the PWM drive signals G 1 and G 4 of the inverter switch are high, the short-circuit state of the load continues, and the inverter output current i inv flowing through the filter inductor suddenly rises again. The upper limit of the hysteresis comparator is passed.
  • the output signal CL of the fault-tolerant PWM circuit is immediately low again, and the AND gate suppresses all PWM drive signals (G 1 , G 2 , G 3 , G 4 ) of the inverter switch. Therefore, all of the power converter is switched off so that the inverter output current ( i inv ) does not increase any more and falls again. Due to this operation principle, the inverter output stage current i inv does not exceed the upper limit of the hysteresis comparator under any circumstances, thereby preventing the switch of the power converter from being destroyed by a short circuit accident.
  • the inverter When the short circuit accident on the load side is eliminated, the inverter immediately operates in the normal operation mode.
  • the switching period of the power conversion switch in the fault tolerance operation mode is determined by the difference (hysteresis width) between the upper limit value and the lower limit value of the hysteresis comparator.
  • the switching period of the power conversion switch is shortened in the fault-tolerant operation mode, and the switching frequency is increased.
  • the hysteresis width is widened, the switching period is longer and the switching frequency is lowered.
  • FIG. 5 and 6 are diagrams showing experimental waveforms according to the load short operation of the inverter by the fault tolerance PWM switching of the present invention.
  • the inverter output current ( i inv) ) Can be safely suppressed within the limits.
  • FIG. 7 is a diagram illustrating a load short operation test waveform of an inverter using fault tolerant PWM switching according to the present invention.
  • the test waveform of (a) shows the load output voltage ( V Load ) and the load current ( i Load ) of the inverter when a load shorting accident of about 110 ms occurs. It can be seen that the fault current is suppressed within the limit value by fault tolerance PWM switching.
  • the experimental waveform of (b) is an enlargement of a part of the waveform during the load shortage accident among the experimental waveforms of (a), and it can be seen that the accidental load current alternates between the upper and lower limits of the hysteresis comparator within the switching period of the inverter.
  • the current of the output terminal of the inverter switching unit and the voltage of the LC filter unit output terminal are detected, the detected current value is converted into an absolute value, and compared with a preset current value to output a corresponding CL signal. At this time, if the current value converted to the absolute value is smaller than the preset upper limit current value, the CL signal is output high. If the current value converted to the absolute value is greater than the preset upper limit current value, the CL signal is low ( low).
  • the inverter switching unit When the CL signal is output high, the inverter switching unit is turned on. When the CL signal is output low, the inverter switching unit is turned off. At this time, the output CL signal is input to control the switch on / off operation of the inverter switching unit.
  • the current and the voltage of the inverter switching unit are adjusted according to the on / off control of the switching operation.
  • the load voltage of the output stage of the LC filter unit is detected and controlled as a reference sine wave voltage, and a comparison triangular wave having a switching frequency of the reference sine wave voltage is input to output a pulse width driving signal to the inverter switching unit.
  • FIG. 3 An application example of the fault tolerance type PWM switching technique proposed in FIG. 3 is shown. This method is not only applicable to PWM inverters, but is applicable to all power converters having a PWM switching scheme with a constant switching period, such as a DC-DC converter, a chopper, a buck converter, and a boost converter.

Abstract

An apparatus for converting power by means of fault-tolerant PWM switching and a method for controlling same, according to the present invention, comprises: an inverter switching portion for outputting a pulse signals corresponding to the size of a DC-link voltage; an LC filter portion for smoothing a voltage pulse signal outputted by the inverter switching portion and then outputting same as a sine wave signal; a current sensor portion for detecting current outputted by the inverter switching portion; a PWM switching control portion for comparing an absolute value of a current value detected from the current sensor portion and a predetermined current value, and then controlling the inverter switching portion according to an output value corresponding to same; a control portion for detecting an output-end load voltage of the LC filter portion and controlling and outputting same as a reference sine wave voltage; and a PWM generator for receiving the sine wave voltage outputted from the control portion, receiving an inputted comparative triangle wave having a predetermined switching frequency, and outputting a pulse width driving signal to the inverter switching portion.

Description

고장 감내형 PWM 스위칭에 의한 전력변환장치 및 그 제어방법Fault-tolerant PWM switching power converter and control method thereof
본 발명은 고장 감내형 PWM 스위칭에 의한 전력변환장치에 관한 것으로, 특히 PWM 스위칭에 의한 전력변환장치에 있어서 인버터의 출력전류를 검출하여 부하 단락 사고시 그에 대한 스위칭을 제어함으로써 안정적으로 부하를 보호할 수 있는 고장 감내형 PWM 스위칭에 의한 전력변환장치 및 그 제어방법에 관한 것이다.The present invention relates to a power conversion device by fault-tolerant PWM switching, in particular, in the power conversion device by PWM switching can detect the output current of the inverter and control the switching to it in the event of a load short circuit to protect the load stably. The present invention relates to a power conversion device using a fault-tolerant PWM switching and a control method thereof.
통상적인 ESS(Energy Storage System) 장치는, 계통 측에 전력의 수요가 적을 시 충전을 행하며, 전력의 수요가 많을 시 축전 부 전원을 방전시켜 계통에 전력을 공급하며, 아울러 이와 동시에 무효전력을 계통에 순시로 보정하여 전력을 안정 시키는 역할을 가진다.A typical ESS (Energy Storage System) device charges when the demand for power is low on the grid side, and discharges power from the storage unit when the demand for power is high, and simultaneously supplies reactive power to the grid. It has a role of stabilizing power by instantaneous correction.
이러한 ESS 장치는, 계통 측 전력을 제공받아 직류 전원으로 변환하고 수신된 직류 전원을 교류 전원으로 변환하여 계통 측과 부하 측으로 전달하는 컨버터와, 상기 컨버터의 직류 전원을 상기 컨버터로 공급하는 충전부를 포함하며, 상기 각 구성 요소들의 동작을 제어하는 PWM 제어부를 포함한다.The ESS device includes a converter that receives grid-side power and converts the power into DC power, converts the received DC power into AC power, and transfers the power to the grid and the load, and a charging unit for supplying the DC power of the converter to the converter. It includes a PWM control unit for controlling the operation of each component.
PWM(Pulse Width Modulation) 스위칭은 주어진 스위칭 주기 내에서 스위칭-온 시간의 비율에 따라 출력전압 또는 전류의 크기를 제어한다. 이를 듀티비 제어라고도 한다.Pulse Width Modulation (PWM) switching controls the magnitude of the output voltage or current according to the ratio of switching-on time within a given switching period. This is also called duty ratio control.
도 1은 종래에 따른 PWM 인버터를 갖는 전력변환장치의 구성을 개략적으로 도시한 도면이다. 도 1에 도시된 바와 같이, 제어부(150)에서 단상 인버터(120)의 출력전압을 정현적으로 제어하고 출력단 필터 커패시터(130) 양단의 전압(VLoad)를 피드백 받아서 기준 정현파(Vref)가 되도록 제어한다. 이때, 제어전압(VCon)은 정현파형의 형태가 되며 PWM 발생기(160)에서 기 설정된 스위칭 주파수와 같은 주파수를 갖는 비교삼각파(VTri)와 비교하여 인버터 스위치(120)의 PWM 구동신호(G1, G2, G3, G4)를 만들어 낸다. 다시 말해, 제어전압(VCon)이 비교삼각파(VTri) 보다 크면 PWM 구동신호(G1, G4)가 하이(High)의 상태가 되어서 해당 스위치(SW1, SW4)를 온 시키고, 반대로 제어전압(VCon)이 비교삼각파(VTri) 보다 작으면 PWM 구동신호(G2, G3)가 하이(High)의 상태가 되어서 해당 스위치(SW2, SW3)를 온 시킨다.1 is a view schematically showing the configuration of a power converter having a PWM inverter according to the prior art. As shown in FIG. 1, the control unit 150 sineically controls the output voltage of the single-phase inverter 120 and receives a voltage V Load across the output stage filter capacitor 130 to receive a reference sine wave V ref . Control as possible. At this time, the control voltage (V Con ) is in the form of a sinusoidal waveform and compared with the comparison triangle wave (V Tri ) having the same frequency as the preset switching frequency in the PWM generator 160 PWM drive signal (G) of the inverter switch (120) 1 , G 2 , G 3 , G 4 ) In other words, when the control voltage (V Con ) is greater than the comparison triangular wave (V Tri ), the PWM driving signals (G 1 , G 4 ) are in a high state and the corresponding switches (SW 1 , SW 4 ) are turned on. On the contrary, when the control voltage V Con is smaller than the comparative triangular wave V Tri , the PWM driving signals G 2 and G 3 are in a high state, thereby turning on the corresponding switches SW 2 and SW 3 .
도 2는 종래에 따른 PWM 인버터를 갖는 전력변환장치의 PWM 구동 신호와 출력 전압 신호의 예를 도시한 도면이다. 도 2에 도시된 바와 같이, 바이폴라 PWM 구동의 예로써 PWM 구동신호(G1, G4) 및 (G2, G3)가 짝을 이루어 스위칭 되며, 인버터출력전압(Vinv)은 직류링크전압의 크기에 따라 +Vdc 또는 -Vdc의 값을 갖는다. 이러한 PWM 스위칭을 함으로써 인버터의 출력전압은 펄스형태의 전압이 되지만, L-C 필터를 거쳐서 평활화 된 부하출력전압(VLoad)은 그림과 같이 인버터출력전압 (Vinv)의 시간평균 값에 해당하는 정현파형이 된다.2 is a diagram illustrating an example of a PWM drive signal and an output voltage signal of a power converter having a conventional PWM inverter. As shown in FIG. 2, as an example of bipolar PWM driving, PWM driving signals G 1 and G 4 and G 2 and G 3 are paired and switched, and the inverter output voltage V inv is a DC link voltage. It has a value of + Vdc or -Vdc depending on the size of. By this PWM switching output voltage of the inverter, but the voltage of the pulse type, the load output voltage smoothed through an LC filter (V Load) is corresponding to the time average value of the inverter output voltage (V inv) as shown sinusoidal Becomes
그런데 도 2와 같이 스위치 패턴이 결정되어 있는 상황에서 부하측에서 단락사고 등의 상황이 발생하는 경우, 인버터 출력전류(i inv )가 급격히 상승하여 전력변환부의 스위치에는 허용전류 이상의 과전류가 흘러서 동작이 중지되거나 인버터 시스템의 재가동이 불가능한 고장상태가 되는 문제점이 발생된다.However, when a short circuit accident occurs on the load side in a situation where the switch pattern is determined as shown in FIG. 2, the inverter output current i inv rises rapidly and the switch of the power conversion section flows an overcurrent above the allowable current to stop the operation. Or a fault condition in which the inverter system cannot be restarted.
본 발명이 해결하고자 하는 기술적 과제는 PWM 스위칭에 의한 전력변환장치에 있어서 인버터의 출력전류를 검출하여 부하 단락 사고시 그에 대한 스위칭을 제어함으로써 안정적으로 부하를 보호할 수 있는 고장 감내형 PWM 스위칭에 의한 전력변환장치 및 그 제어방법을 제공하는 것이다.The technical problem to be solved by the present invention is to detect the output current of the inverter in the power conversion device by PWM switching power by the fault-tolerant PWM switching that can reliably protect the load by controlling the switching to the load short circuit accident It is to provide an inverter and a control method thereof.
본 발명에서 이루고자 하는 기술적 과제들은 이상에서 언급한 기술적 과제들로 제한되지 않으며, 언급하지 않은 또 다른 기술적 과제들은 아래의 기재로부터 본 발명이 속하는 기술분야에서 통상의 지식을 가진 자에게 명확하게 이해될 수 있을 것이다.The technical problems to be achieved in the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned above will be clearly understood by those skilled in the art from the following description. Could be.
상기 기술적 과제를 해결하기 위한 본 발명에 따른 고장 감내형 PWM 스위칭에 의한 전력변환장치는, 직류링크전압의 크기에 대응하여 펄스 신호로 출력하는 인버터 스위칭부와; 상기 인버터 스위칭부에서 출력되는 전압 펄스 신호를 평활화하여 정현파 신호로 출력하는 LC 필터부와; 상기 인버터 스위칭부에서 출력되는 전류를 검출하는 전류 센서부와; 상기 전류 센서부에서 검출된 전류값의 절대값과 기 설정된 전류값을 비교하여 그에 대응하는 출력값에 따라 상기 인버터 스위칭부를 제어하는 PWM 스위칭 제어부와; 상기 LC 필터부의 출력단 부하전압을 검출하여 기준 정현파 전압으로 제어하여 출력하는 제어부; 및 상기 제어부에서 출력된 정현파 전압을 입력받고 기 설정된 스위칭 주파수를 갖는 비교 삼각파를 입력받아 상기 인버터 스위칭부에 펄스 폭 구동 신호를 출력하는 PWM 발생기를 포함하는 점에 그 특징이 있다.According to an aspect of the present invention, there is provided a power conversion apparatus using fault tolerant PWM switching, including: an inverter switching unit outputting a pulse signal corresponding to a magnitude of a DC link voltage; An LC filter unit for smoothing the voltage pulse signal output from the inverter switching unit and outputting the sinusoidal signal; A current sensor unit detecting a current output from the inverter switching unit; A PWM switching controller for comparing the absolute value of the current value detected by the current sensor unit with a preset current value and controlling the inverter switching unit according to an output value corresponding thereto; A control unit which detects the load voltage of the output stage of the LC filter unit and controls the load voltage to a reference sine wave voltage; And a PWM generator for receiving a sine wave voltage output from the controller and receiving a comparison triangle wave having a preset switching frequency to output a pulse width driving signal to the inverter switching unit.
여기서, 특히 상기 PWM 스위칭 제어부는 상기 전류 센서부에서 검출된 전류값을 절대값으로 변환하는 절대값 변환부와; 상기 절대값으로 변환된 전류값을 기 설정된 상한 전류값과 비교하여 그에 대응하는 CL 신호를 출력하는 히스테리시스 비교기 및 상기 히스테리시스 비교기에서 출력되는 CL 신호에 따라 상기 인버터 스위칭부를 제어하는 앤드 게이트부를 포함하는 점에 그 특징이 있다.In particular, the PWM switching control unit may include an absolute value converting unit converting the current value detected by the current sensor unit into an absolute value; A hysteresis comparator for comparing the current value converted into the absolute value with a preset upper limit current value and outputting a CL signal corresponding thereto, and an AND gate part for controlling the inverter switching unit according to the CL signal output from the hysteresis comparator. Has its features.
여기서, 특히 상기 히스테리시스 비교기에서 절대값으로 변환된 전류값이 기 설정된 상한 전류값보다 작으면 CL 신호는 하이(high)로 출력되고, 절대값으로 변환된 전류값이 기 설정된 상한 전류값보다 크면 CL 신호는 로우(low)로 출력되는 점에 그 특징이 있다.Here, in particular, when the current value converted into an absolute value in the hysteresis comparator is smaller than a preset upper limit current value, the CL signal is output high, and when the current value converted into an absolute value is greater than the preset upper limit current value, CL The characteristic is that the signal is output low.
여기서, 특히 상기 앤드 게이트부는 상기 히스테리시스 비교기에서 출력되는 CL 신호가 하이(high)로 출력되면 인버터 스위칭부를 온(ON)시키고, CL 신호가 로우(low)로 출력되면 인버터 스위칭부를 오프(OFF)시키는 점에 그 특징이 있다.Here, in particular, the AND gate unit turns on the inverter switching unit when the CL signal output from the hysteresis comparator is output high, and turns off the inverter switching unit when the CL signal is output low. It has that feature.
여기서, 특히 상기 전류 센서부는 상기 인버터 스위칭부의 출력단 양단의 전류 값을 검출하는 점에 그 특징이 있다.Here, in particular, the current sensor unit is characterized in that it detects the current value across the output terminal of the inverter switching unit.
여기서, 특히 상기 PWM 스위칭 제어부에서 출력되는 스위칭 주파수는 히스테리시스 폭에 대응하여 결정되는 점에 그 특징이 있다.In particular, the switching frequency output from the PWM switching controller is characterized in that it is determined corresponding to the hysteresis width.
여기서, 특히 상기 히스테리시스폭이 좁으면 스위칭 주파수가 증가하고, 상기 히스테리시스폭이 넓으면 스위칭 주파수가 감소하는 점에 그 특징이 있다.Here, in particular, the narrower the hysteresis width, the higher the switching frequency, the wider the hysteresis width is characterized in that the switching frequency is reduced.
여기서, 특히 상기 LC 필터부의 출력 양단의 부하 전압을 감지하는 전압 센서부를 더 포함하는 점에 그 특징이 있다.Here, in particular, it is characterized in that it further comprises a voltage sensor unit for detecting the load voltage across the output of the LC filter unit.
또한, 본 발명에 따른 고장 감내형 PWM 스위칭에 의한 전력변환장치의 제어방법은 인버터 스위칭부의 출력단의 전류 및 LC 필터부 출력단의 전압을 검출하는 단계와; 상기 검출된 전류값을 절대값으로 변환한 후 기 설정된 전류값과 비교하여 그에 대응하는 CL 신호를 출력하는 단계와; 상기 출력되는 CL 신호를 입력받아 상기 인버터 스위칭부의 스위치 온/오프 동작을 제어하는 단계와; 상기 스위칭 동작의 온/오프 제어에 따라 상기 인버터 스위칭부의 전류 및 전압을 조절하는 단계를 포함하는 점에 그 특징이 있다.In addition, the control method of the power conversion apparatus by the fault-tolerant PWM switching according to the present invention includes the steps of detecting the current of the output terminal of the inverter switching unit and the voltage of the LC filter output stage; Converting the detected current value into an absolute value and comparing the current value with a preset current value to output a CL signal corresponding thereto; Controlling the switch on / off operation of the inverter switching unit by receiving the output CL signal; It characterized in that it comprises the step of adjusting the current and voltage of the inverter switching unit in accordance with the on / off control of the switching operation.
여기서, 특히 상기 CL 신호를 출력하는 단계에서 절대값으로 변환된 전류값이 기 설정된 상한 전류값보다 작으면 CL 신호는 하이(high)로 출력되고, 절대값으로 변환된 전류값이 기 설정된 상한 전류값보다 크면 CL 신호는 로우(low)로 출력되는 점에 그 특징이 있다.Here, in particular, in the step of outputting the CL signal, if the current value converted to the absolute value is smaller than the preset upper limit current value, the CL signal is outputted high and the current value converted to the absolute value is the preset upper limit current. If it is larger than the value, the CL signal is characterized in that it is output low.
여기서, 특히 상기 CL 신호가 하이(high)로 출력되면 인버터 스위칭부를 온(ON)시키고, CL 신호가 로우(low)로 출력되면 인버터 스위칭부를 오프(OFF)시키는 점에 그 특징이 있다.In particular, the inverter switching unit is turned on when the CL signal is output high, and the inverter switching unit is turned off when the CL signal is output low.
여기서, 특히 상기 LC 필터부의 출력단 부하전압을 검출하여 기준 정현파 전압으로 제어하는 단계와; 상기 기준 정현파 전압의 스위칭 주파수를 갖는 비교 삼각파를 입력받아 인버터 스위칭부에 펄스 폭 구동 신호를 출력하는 단계를 더 포함하는 점에 그 특징이 있다.In particular, the step of detecting the load voltage of the output terminal of the LC filter unit to control the reference sinusoidal voltage; And receiving a comparison triangular wave having a switching frequency of the reference sinusoidal voltage and outputting a pulse width driving signal to an inverter switching unit.
여기서, 특히 상기 스위칭 주파수는 히스테리시스 폭에 대응하여 히스테리시스폭이 좁으면 스위칭 주파수가 증가하고, 히스테리시스폭이 넓으면 스위칭 주파수가 감소하는 점에 그 특징이 있다.In particular, the switching frequency is characterized in that the switching frequency increases when the hysteresis width is narrow corresponding to the hysteresis width, and the switching frequency decreases when the hysteresis width is wide.
본 발명에 따르면, PWM 스위칭에 의한 전력변환장치에 있어서 인버터의 출력전류를 검출하여 부하 단락 사고시 그에 대한 스위칭을 제어함으로써 안정적으로 부하를 보호할 수 있다.According to the present invention, it is possible to reliably protect the load by detecting the output current of the inverter in the power conversion device by PWM switching and controlling the switching to the load short circuit accident.
도 1은 종래에 따른 PWM 스위칭에 의한 전력변환장치의 구성을 개략적으로 도시한 도면.1 is a view schematically showing the configuration of a power conversion apparatus by PWM switching according to the prior art.
도 2는 종래에 따른 PWM 스위칭에 의한 전력변환장치의 PWM 구동 신호와 출력 전압을 도시한 도면.2 is a diagram illustrating a PWM driving signal and an output voltage of a power conversion device by PWM switching according to the related art.
도 3은 본 발명에 따른 고장 감내형 PWM 스위칭에 의한 전력변환장치의 구성을 도시한 도면.Figure 3 is a diagram showing the configuration of a power conversion device by fault tolerance PWM switching according to the present invention.
도 4는 본 발명의 고장 감내형 PWM 스위칭에 의한 전력변환장치의 운전 조건에 따른 출력 파형을 도시한 도면.Figure 4 is a view showing the output waveform according to the operating conditions of the power conversion device by fault tolerance PWM switching of the present invention.
도 5 및 도 6은 본 발명의 고장감내 PWM 스위칭에 의한 인버터의 부하단락운전에 따른 실험 파형을 도시한 도면들.5 and 6 are diagrams showing the experimental waveform according to the load short operation of the inverter by the fault tolerance PWM switching of the present invention.
도 7은 본 발명의 고장감내형 PWM 스위칭에 의한 인버터의 부하단락운전 실험파형을 도시한 도면.FIG. 7 is a diagram illustrating a load short operation test waveform of an inverter using fault tolerant PWM switching according to the present invention; FIG.
이하 첨부된 도면을 참조하여 본 발명이 속하는 기술분야에서 통상의 지식을 가진 자가 본 발명을 용이하게 실시할 수 있는 바람직한 실시 예를 상세히 설명한다. 다만, 본 발명의 바람직한 실시 예에 대한 동작 원리를 상세하게 설명함에 있어 관련된 공지 기능 또는 구성에 대한 구체적인 설명이 본 발명의 요지를 불필요하게 흐릴 수 있다고 판단되는 경우에는 그 상세한 설명을 생략한다.DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, in describing in detail the operating principle of the preferred embodiment of the present invention, if it is determined that the detailed description of the related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.
또한, 도면 전체에 걸쳐 유사한 기능 및 작용을 하는 부분에 대해서는 동일한 도면 부호를 사용한다.In addition, the same reference numerals are used for parts having similar functions and functions throughout the drawings.
덧붙여, 명세서 전체에서, 어떤 부분이 다른 부분과 '연결'되어 있다고 할때, 이는 '직접적으로 연결'되어 있는 경우뿐만 아니라, 그 중간에 다른 소자를 사이에 두고 '간접적으로 연결'되어 있는 경우도 포함한다. 또한 어떤 구성 요소를 '포함'한다는 것은, 특별히 반대되는 기재가 없는 한 다른 구성요소를 제외하는 것이 아니라, 다른 구성요소를 더 포함할 수 있는 것을 의미한다.In addition, throughout the specification, when a part is 'connected' to another part, it is not only 'directly connected' but also 'indirectly connected' with another element in between. Include. In addition, the term 'comprising' a certain component means that the component may be further included, without excluding the other component unless specifically stated otherwise.
이하 본 발명의 일 실시 예를 첨부된 도면을 참조하여 상세히 설명한다.Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.
도 3은 본 발명에 따른 고장 감내형 PWM 스위칭에 의한 전력변환장치의 구성을 도시한 도면이다. 도 3에 도시된 바와 같이, 본 발명에 따른 고장 감내형 PWM 스위칭에 의한 전력변환장치는, 직류링크전압의 크기에 대응하여 펄스 신호로 출력하는 인버터 스위칭부(320)와; 상기 인버터 스위칭부(320)에서 출력되는 전압 펄스 신호를 평활화하여 정현파 신호로 출력하는 LC 필터부(340)와; 상기 인버터 스위칭부(320)에서 출력되는 전류를 검출하는 전류 센서부(330)와; 상기 전류 센서부(330)에서 검출된 전류값의 절대값과 기 설정된 전류값을 비교하여 그에 대응하는 출력값에 따라 상기 인버터 스위칭부(320)를 제어하는 PWM 스위칭 제어부(390)와; 상기 LC 필터부(340)의 출력단 부하전압을 검출하여 기준 정현파 전압으로 제어하여 출력하는 제어부(370); 및 상기 제어부(370)에서 출력된 정현파 전압을 입력받고 기 설정된 스위칭 주파수를 갖는 비교 삼각파를 입력받아 상기 인버터 스위칭부(320)에 펄스 폭 구동 신호를 출력하는 PWM 발생기(380) 및 상기 LC 필터부(340)의 출력 양단의 부하 전압을 감지하는 전압 센서부(350)를 포함하여 구성된다.3 is a diagram illustrating a configuration of a power conversion apparatus using fault tolerant PWM switching according to the present invention. As shown in FIG. 3, the power conversion device using fault tolerant PWM switching according to the present invention includes an inverter switching unit 320 outputting a pulse signal corresponding to the magnitude of the DC link voltage; An LC filter unit 340 for smoothing the voltage pulse signal output from the inverter switching unit 320 and outputting the sinusoidal signal; A current sensor unit 330 for detecting a current output from the inverter switching unit 320; A PWM switching controller 390 for comparing the absolute value of the current value detected by the current sensor unit 330 with a preset current value and controlling the inverter switching unit 320 according to an output value corresponding thereto; A control unit 370 for detecting the output voltage of the output stage of the LC filter unit 340 and controlling and outputting the control signal to a reference sine wave voltage; And a PWM generator 380 and the LC filter unit which receive a sine wave voltage output from the controller 370 and receive a comparison triangular wave having a preset switching frequency and output a pulse width driving signal to the inverter switching unit 320. It is configured to include a voltage sensor unit 350 for detecting the load voltage across the output of the (340).
상기 인버터 스위칭부(320)은 적어도 하나 이상의 스위칭 소자를 가지고 있으며, IGBT 스위칭소자 4개로 이루어진 풀브리지(Full Bridge) 구조이다. 상기 4개의 스위칭 소자 각각에는 스위칭소자 양단에 역병렬로 다이오드가 접속된다.The inverter switching unit 320 has at least one switching element, and has a full bridge structure consisting of four IGBT switching elements. Each of the four switching elements is connected with diodes in anti-parallel across the switching elements.
여기서, 상기 인버터 스위칭부(320)의 구조는 풀브리지 이외에도 하프브리지(Half Bridge) 구조 또는 푸쉬-풀(Push-Pull) 구조도 적용할 수 있다.Here, in addition to the full bridge, the inverter switching unit 320 may also have a half bridge structure or a push-pull structure.
또한, 상기 인버터 스위칭부(320)의 IGBT의 게이트 전극의 연결 부분에는 PWM 스위칭 제어부(390)가 연결된다.In addition, the PWM switching controller 390 is connected to the connection portion of the gate electrode of the IGBT of the inverter switching unit 320.
상기 제어부(370)는 상기 인버터 스위칭부(320)의 스위칭 동작을 제어하여 부하의 출력 전압의 크기 및 형태를 제어하도록 하는 것으로서, 사용자가 원하는 출력 전압의 크기 및 형태를 선택하고 그에 대응하는 전압을 제공한다.The controller 370 controls the switching operation of the inverter switching unit 320 to control the size and shape of the output voltage of the load. The control unit 370 selects the size and shape of the output voltage desired by the user and selects a voltage corresponding thereto. to provide.
보다 구체적으로, 상기 전압 센서부(350)에서 상기 LC 필터부(340)의 출력 양단의 부하 전압을 감지하고 기준 전압을 입력받아 그에 대응하는 전압을 제어하여 상기 PWM 발생기에 출력하게 된다.More specifically, the voltage sensor unit 350 detects the load voltage across the output of the LC filter unit 340, receives a reference voltage, controls a voltage corresponding thereto, and outputs the voltage to the PWM generator.
상기 전류 센서부(330)는 상기 인버터 스위칭부(320)의 부하 전류를 검출하여 상기 PWM 스위칭 제어부로 출력한다.The current sensor unit 330 detects a load current of the inverter switching unit 320 and outputs the load current to the PWM switching control unit.
상기 PWM 스위칭 제어부(390)는 절대값 변환부(391), 히스테리시스 비교기(392) 및 앤드 게이트부(393)를 포함한다.The PWM switching controller 390 includes an absolute value converter 391, a hysteresis comparator 392 and an AND gate 393.
상기 절대값 변환부(391)는 상기 전류 센서부(330)에서 검출된 전류값을 절대값으로 변환하고, 상기 히스테리시스 비교기(392)에서는 절대값으로 변환된 전류값을 기 설정된 상한 전류값과 비교하여 그에 대응하는 CL 신호를 출력하게 된다. 그리고, 상기 앤드 게이트부(393)는 상기 히스테리시스 비교기(392)에서 출력되는 CL 신호에 따라 상기 인버터 스위칭부(320)를 제어하게 된다.The absolute value converter 391 converts the current value detected by the current sensor unit 330 into an absolute value, and the hysteresis comparator 392 compares the current value converted into an absolute value with a preset upper limit current value. As a result, a corresponding CL signal is output. The AND gate 393 controls the inverter switching unit 320 according to the CL signal output from the hysteresis comparator 392.
보다 구체적으로, 상기 히스테리시스 비교기(392)는 절대값으로 변환된 전류값이 기 설정된 상한 전류값보다 작으면 CL 신호는 하이(high)로 출력하고, 절대값으로 변환된 전류값이 기 설정된 상한 전류값보다 크면 CL 신호는 로우(low)로 출력하게 된다.More specifically, the hysteresis comparator 392 outputs the CL signal high when the current value converted to the absolute value is smaller than the preset upper limit current value, and the upper limit current to which the current value converted to the absolute value is preset. If it is larger than the value, the CL signal is output low.
상기 앤드 게이트부(393)는 상기 히스테리시스 비교기(392)에서 출력되는 CL 신호가 하이(high)로 출력되면 상기 인버터 스위칭부(320)를 온(ON) 시키고, CL 신호가 로우(low)로 출력되면 인버터 스위칭부를 오프(OFF)시키게 된다.The AND gate 393 turns on the inverter switching unit 320 when the CL signal output from the hysteresis comparator 392 is high, and outputs the CL signal low. When the inverter is switched off (OFF).
도 4는 본 발명의 고장 감내형 PWM 스위칭에 의한 전력변환장치의 운전 조건에 따른 출력 파형을 도시한 도면이다. 도 5의 정상 모드에서 고장감내형 PWM 회로의 출력신호 CL은 항상 하이(High) 상태이며, 인버터 스위칭부의 PWM 구동신호(G1, G2, G3, G4)는 상기 앤드(AND) 게이트를 통과하여 정상적으로 전력변환 스위치를 동작시켜서 인버터 출력전압(v inv )을 생성시킨다.4 is a view showing the output waveform according to the operating conditions of the power conversion device by the fault-tolerant PWM switching of the present invention. In the normal mode of FIG. 5, the output signal CL of the fault tolerance PWM circuit is always in a high state, and the PWM driving signals G 1 , G 2 , G 3 , and G 4 of the inverter switching unit are connected to the AND gate. After passing through, operate the power conversion switch normally to generate inverter output voltage ( v inv ).
인버터 출력전압(v inv )과 부하전압(v Load )의 차이는 필터 인덕터 양단에 인가되고, 인버터 출력전류(i inv )는 필터 인덕터 양단에 인가되는 전압의 크기와 극성에 따라 소정의 평균값을 중심으로 상승 및 하강을 반복하게 된다.The difference between the inverter output voltage ( v inv ) and the load voltage ( v Load ) is applied across the filter inductor, and the inverter output current ( i inv ) is centered on a predetermined average value depending on the magnitude and polarity of the voltage applied across the filter inductor. Rise and fall repeatedly.
한편, 부하가 단락되는 사고가 발생하는 경우인 고장감내(FRT) 모드에서 (b)와 같이 부하전압(v Load )이 거의 영이 되므로, 필터 인덕터에 걸리는 전압이 증대하여 인버터 출력전류(i inv )의 기울기는 급상승하게 되고, 이는 히스테리시스 비교기의 상한선을 지나게 된다. 인버터 출력전류(i inv )의 절대값이 히스테리시스 비교기의 상한값보다 크게 되면 고장감내형 PWM 회로의 출력신호 CL은 즉시 로우(Low) 상태가 되고 앤드(AND) 게이트가 닫혀져서 기존의 인버터 스위치의 PWM 구동신호(G1, G2, G3, G4)를 모두 억제하므로, 전력변환기의 스위치가 모두 꺼져서 인버터 출력전류(i inv )는 더 이상 증가하지 못하고 하강하게 된다.On the other hand, in the fault tolerance (FRT) mode where the load is shorted, the load voltage ( v Load ) becomes almost zero as in (b), so that the voltage applied to the filter inductor increases to increase the inverter output current ( i inv ). The slope of becomes steep, which passes the upper limit of the hysteresis comparator. If the absolute value of the inverter output current ( i inv ) is greater than the upper limit of the hysteresis comparator, the output signal CL of the fault-tolerant PWM circuit immediately goes low and the AND gate is closed to close the PWM of the existing inverter switch. Since the driving signals G 1 , G 2 , G 3 , and G 4 are all suppressed, the power converter is switched off so that the inverter output current i inv no longer increases and falls.
인버터 출력전류(i inv )의 절대값이 점차 감소하여 히스테리시스 비교기의 하한값보다 작게 되면 고장감내형 PWM 회로의 출력신호 CL은 즉시 하이(High) 상태가 되고 앤드(AND) 게이트를 열어서 인버터 스위치의 PWM 구동신호(G1, G2, G3, G4)를 모두 통과시킨다. 이때, 인버터 스위치의 PWM 구동신호(G1, G4)가 하이(High) 상태라면, 부하의 단락상태가 계속되고 있기 때문에 필터 인덕터에 흐르는 인버터 출력전류(i inv )는 다시 급상승하게 되고, 이윽고 히스테리시스 비교기의 상한선을 지나게 된다.If the absolute value of the inverter output current ( i inv ) gradually decreases and becomes smaller than the lower limit of the hysteresis comparator, the output signal CL of the fault-tolerant PWM circuit immediately becomes high and the AND gate opens to open the PWM of the inverter switch. Passes all driving signals G 1 , G 2 , G 3 , and G 4 . At this time, if the PWM drive signals G 1 and G 4 of the inverter switch are high, the short-circuit state of the load continues, and the inverter output current i inv flowing through the filter inductor suddenly rises again. The upper limit of the hysteresis comparator is passed.
그러면 고장감내형 PWM 회로의 출력신호 CL은 또다시 즉시 로우(Low) 상태가 되고 앤드(AND) 게이트에 의하여 인버터 스위치의 PWM 구동신호(G1, G2, G3, G4)를 모두 억제하므로, 전력변환기의 스위치가 모두 꺼져서 인버터 출력전류(i inv )는 더 이상 증가하지 못하고 다시 하강하게 된다. 이러한 작동원리에 의하여 인버터 출력단 전류(i inv )는 어떠한 상황에서도 히스테리시스 비교기의 상한값을 넘지 않게 되어 전력변환기의 스위치가 단락사고에 의하여 파괴되는 것을 방지할 수 있다.The output signal CL of the fault-tolerant PWM circuit is immediately low again, and the AND gate suppresses all PWM drive signals (G 1 , G 2 , G 3 , G 4 ) of the inverter switch. Therefore, all of the power converter is switched off so that the inverter output current ( i inv ) does not increase any more and falls again. Due to this operation principle, the inverter output stage current i inv does not exceed the upper limit of the hysteresis comparator under any circumstances, thereby preventing the switch of the power converter from being destroyed by a short circuit accident.
그리고, 부하 측의 단락사고가 제거되면 인버터는 즉시 정상운전 모드로 작동하게 된다.When the short circuit accident on the load side is eliminated, the inverter immediately operates in the normal operation mode.
보다 구체적으로, 고장감내 운전모드에서 전력변환 스위치의 스위칭 주기는 히스테리시스 비교기의 상한값과 하한값의 차이(히스테리시스폭)에 의하여 결정된다. 다시 말해, 히스테리시스 폭을 좁게 하면 고장감내 운전모드에서 전력변환 스위치의 스위칭 주기는 짧아져서 스위칭 주파수가 증가하며, 반대로 히스테리시스 폭을 넓게하면 스위칭 주기가 길어져서 스위칭 주파수는 낮아진다.More specifically, the switching period of the power conversion switch in the fault tolerance operation mode is determined by the difference (hysteresis width) between the upper limit value and the lower limit value of the hysteresis comparator. In other words, when the hysteresis width is narrowed, the switching period of the power conversion switch is shortened in the fault-tolerant operation mode, and the switching frequency is increased. On the contrary, when the hysteresis width is widened, the switching period is longer and the switching frequency is lowered.
또한, 도 5 및 도 6은 본 발명의 고장감내 PWM 스위칭에 의한 인버터의 부하단락운전에 따른 실험 파형을 도시한 도면이다. 도 5에 도시된 바와 같이, 고장감내형 PWM 스위칭에 의한 인버터의 부하단락운전 시뮬레이션에서 30ms에서 60ms 사이에서 부하 측에 단락사고가 발생하였을 때, 고장감내형 PWM 스위칭에 의하여 인버터출력전류(i inv ) 가 제한범위 내로 안전하게 억제되는 것을 볼 수 있다.5 and 6 are diagrams showing experimental waveforms according to the load short operation of the inverter by the fault tolerance PWM switching of the present invention. As shown in FIG. 5, when a short circuit accident occurs on the load side between 30 ms and 60 ms in a load short operation simulation of the inverter by fault tolerance PWM switching, the inverter output current ( i inv) ) Can be safely suppressed within the limits.
한편, 도 7에 도시된 바와 같이, 종래의 PWM 스위칭에 의한 인버터의 부하단락운전 시뮬레이션에서는 30ms에서 60ms 사이에서 부하측에 단락사고가 발생하였을 때 인버터출력전류(i inv )가 급격히 상승하여 안전한 운전범위를 벗어나는 것을 볼 수 있다.On the other hand, as shown in Figure 7, in the load short circuit operation simulation of the inverter by the conventional PWM switching, when the short circuit accident occurs on the load side between 30ms to 60ms, the inverter output current ( i inv ) rapidly rises to the safe operating range You can see it going out.
도 7은 본 발명의 고장감내형 PWM 스위칭에 의한 인버터의 부하단락운전 실험파형을 도시한 도면이다. 도 7에 도시된 바와 같이, (a)의 실험 파형은 약 110ms의 부하단락사고가 발생하였을 경우 인버터의 부하출력측 전압(v Load )과 부하전류(i Load )를 보인다. 고장감내형 PWM 스위칭에 의하여 고장전류가 한계 값 이내로 억제되는 것을 볼 수 있다. 여기서, (b)의 실험파형은 (a)의 실험파형 중 부하단락사고시의 파형 일부를 확대한 것으로 사고부하전류가 인버터의 스위칭 주기 내에서 히스테리시스비교기의 상한값과 하한값 사이를 오가는 것을 볼 수 있다.FIG. 7 is a diagram illustrating a load short operation test waveform of an inverter using fault tolerant PWM switching according to the present invention. As shown in FIG. 7, the test waveform of (a) shows the load output voltage ( V Load ) and the load current ( i Load ) of the inverter when a load shorting accident of about 110 ms occurs. It can be seen that the fault current is suppressed within the limit value by fault tolerance PWM switching. Here, the experimental waveform of (b) is an enlargement of a part of the waveform during the load shortage accident among the experimental waveforms of (a), and it can be seen that the accidental load current alternates between the upper and lower limits of the hysteresis comparator within the switching period of the inverter.
또한, 본 발명에 따른 고장 감내형 PWM 스위칭에 의한 전력변환장치의 제어 방법에 대해 설명하기로 한다.In addition, the control method of the power conversion device by the fault-tolerant PWM switching according to the present invention will be described.
먼저, 인버터 스위칭부의 출력단의 전류 및 LC 필터부 출력단의 전압을 검출하여 검출된 전류값을 절대값으로 변환한 후 기 설정된 전류값과 비교하여 그에 대응하는 CL 신호를 출력하게 된다. 이때, 절대값으로 변환된 전류값이 기 설정된 상한 전류값보다 작으면 CL 신호는 하이(high)로 출력하게 되고, 절대값으로 변환된 전류값이 기 설정된 상한 전류값보다 크면 CL 신호는 로우(low)로 출력하게 된다.First, the current of the output terminal of the inverter switching unit and the voltage of the LC filter unit output terminal are detected, the detected current value is converted into an absolute value, and compared with a preset current value to output a corresponding CL signal. At this time, if the current value converted to the absolute value is smaller than the preset upper limit current value, the CL signal is output high. If the current value converted to the absolute value is greater than the preset upper limit current value, the CL signal is low ( low).
그리고, 상기 CL 신호가 하이(high)로 출력되면 인버터 스위칭부를 온(ON)시키고, CL 신호가 로우(low)로 출력되면 인버터 스위칭부를 오프(OFF)시키게 된다. 이때, 상기 출력되는 CL 신호를 입력받아 상기 인버터 스위칭부의 스위치 온/오프 동작을 제어하게 된다.When the CL signal is output high, the inverter switching unit is turned on. When the CL signal is output low, the inverter switching unit is turned off. At this time, the output CL signal is input to control the switch on / off operation of the inverter switching unit.
그리고, 상기 스위칭 동작의 온/오프 제어에 따라 상기 인버터 스위칭부의 전류 및 전압을 조절하게 된다.Then, the current and the voltage of the inverter switching unit are adjusted according to the on / off control of the switching operation.
한편, 상기 LC 필터부의 출력단 부하전압을 검출하여 기준 정현파 전압으로 제어하고, 상기 기준 정현파 전압의 스위칭 주파수를 갖는 비교 삼각파를 입력받아 인버터 스위칭부에 펄스 폭 구동 신호를 출력하게 된다.Meanwhile, the load voltage of the output stage of the LC filter unit is detected and controlled as a reference sine wave voltage, and a comparison triangular wave having a switching frequency of the reference sine wave voltage is input to output a pulse width driving signal to the inverter switching unit.
따라서, 이와 같이 PWM 스위칭에 의한 전력변환장치는 부하측의 단락사고에 대하여 매우 취약하다. 이러한 문제를 개선하기 위하여 고장감내형 PWM 스위칭기술을 제안한다. 도 3에 제안하는 고장감내형 PWM 스위칭기술의 적용례를 보인다. 이 방법은 PWM 인버터에만 적용되는 것은 아니고, DC-DC 컨버터, 쵸퍼, 벅컨버터, 부스트 컨버터 등, 일정한 스위칭 주기를 갖는 PWM 스위칭 방식을 갖는 모든 전력변환기에 적용 가능하다.Therefore, the power conversion device by PWM switching is thus very vulnerable to a short circuit accident on the load side. To solve this problem, we propose a fault-tolerant PWM switching technology. An application example of the fault tolerance type PWM switching technique proposed in FIG. 3 is shown. This method is not only applicable to PWM inverters, but is applicable to all power converters having a PWM switching scheme with a constant switching period, such as a DC-DC converter, a chopper, a buck converter, and a boost converter.
이상에서 설명한 바와 같이, 본 발명의 상세한 설명에서는 본 발명의 바람직한 실시 예에 관하여 설명하였으나, 본 발명이 속하는 기술분야에서 통상의 지식을 가진 자라면 본 발명의 범주에서 벗어나지 않는 한도 내에서 여러 가지 변형이 가능함은 물론이다. 따라서 본 발명의 권리 범위는 설명된 실시 예에 국한되어 정해져서는 안되며, 후술하는 청구범위뿐만 아니라, 이와 균등한 것들에 의해 정해져야 한다.As described above, in the detailed description of the present invention has been described with respect to preferred embodiments of the present invention, those skilled in the art to which the present invention pertains various modifications without departing from the scope of the present invention Of course this is possible. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined by the equivalents as well as the claims to be described later.

Claims (13)

  1. 직류링크전압의 크기에 대응하여 펄스 신호로 출력하는 인버터 스위칭부와;An inverter switching unit for outputting a pulse signal corresponding to the magnitude of the DC link voltage;
    상기 인버터 스위칭부에서 출력되는 전압 펄스 신호를 평활화하여 정현파 신호로 출력하는 LC 필터부와;An LC filter unit for smoothing the voltage pulse signal output from the inverter switching unit and outputting the sinusoidal signal;
    상기 인버터 스위칭부에서 출력되는 전류를 검출하는 전류 센서부와;A current sensor unit detecting a current output from the inverter switching unit;
    상기 전류 센서부에서 검출된 전류값의 절대값과 기 설정된 전류값을 비교하여 그에 대응하는 출력값에 따라 상기 인버터 스위칭부를 제어하는 PWM 스위칭 제어부와;A PWM switching controller for comparing the absolute value of the current value detected by the current sensor unit with a preset current value and controlling the inverter switching unit according to an output value corresponding thereto;
    상기 LC 필터부의 출력단 부하전압을 검출하여 기준 정현파 전압으로 제어하여 출력하는 제어부; 및A control unit which detects the load voltage of the output stage of the LC filter unit and controls the load voltage to a reference sine wave voltage; And
    상기 제어부에서 출력된 정현파 전압을 입력받고 기 설정된 스위칭 주파수를 갖는 비교 삼각파를 입력받아 상기 인버터 스위칭부에 펄스 폭 구동 신호를 출력하는 PWM 발생기를 포함하는 고장 감내형 PWM 스위칭에 의한 전력변환장치.And a PWM generator configured to receive a sine wave voltage output from the controller and to receive a comparison triangular wave having a preset switching frequency, and to output a pulse width driving signal to the inverter switching unit.
  2. 제 1항에 있어서,The method of claim 1,
    상기 PWM 스위칭 제어부는 상기 전류 센서부에서 검출된 전류값을 절대값으로 변환하는 절대값 변환부와;The PWM switching control unit includes an absolute value converting unit converting the current value detected by the current sensor unit into an absolute value;
    상기 절대값으로 변환된 전류값을 기 설정된 상한 전류값과 비교하여 그에 대응하는 CL 신호를 출력하는 히스테리시스 비교기와;A hysteresis comparator for comparing the current value converted into the absolute value with a preset upper limit current value and outputting a CL signal corresponding thereto;
    상기 히스테리시스 비교기에서 출력되는 CL 신호에 따라 상기 인버터 스위칭부를 제어하는 앤드 게이트부를 포함하는 것을 특징으로 하는 고장 감내형 PWM 스위칭에 의한 전력변환장치.And an end gate part controlling the inverter switching part according to a CL signal output from the hysteresis comparator.
  3. 제 2항에 있어서,The method of claim 2,
    상기 히스테리시스 비교기에서 절대값으로 변환된 전류값이 기 설정된 상한 전류값보다 작으면 CL 신호는 하이(high)로 출력되고, 절대값으로 변환된 전류값이 기 설정된 상한 전류값보다 크면 CL 신호는 로우(low)로 출력되는 것을 특징으로 하는 고장 감내형 PWM 스위칭에 의한 전력변환장치.If the current value converted to the absolute value in the hysteresis comparator is smaller than the preset upper limit current value, the CL signal is output high, and if the current value converted to the absolute value is greater than the preset upper limit current value, the CL signal is low. Power conversion device by fault tolerance PWM switching characterized in that the output to (low).
  4. 제 2항에 있어서,The method of claim 2,
    상기 앤드 게이트부는 상기 히스테리시스 비교기에서 출력되는 CL 신호가 하이(high)로 출력되면 인버터 스위칭부를 온(ON)시키고, CL 신호가 로우(low)로 출력되면 인버터 스위칭부를 오프(OFF)시키는 것을 특징으로 하는 고장 감내형 PWM 스위칭에 의한 전력변환장치.The AND gate unit turns on the inverter switching unit when the CL signal output from the hysteresis comparator is output high, and turns off the inverter switching unit when the CL signal is output low. Power converter by fault-tolerant PWM switching.
  5. 제 1항에 있어서,The method of claim 1,
    상기 전류 센서부는 상기 인버터 스위칭부의 출력단 양단의 전류 값을 검출하는 것을 특징으로 하는 고장 감내형 PWM 스위칭에 의한 전력변환장치.And the current sensor unit detects a current value at both ends of an output terminal of the inverter switching unit.
  6. 제 1항에 있어서,The method of claim 1,
    상기 PWM 스위칭 제어부에서 출력되는 스위칭 주파수는 히스테리시스 폭에 대응하여 결정되는 것을 특징으로 하는 고장 감내형 PWM 스위칭에 의한 전력변환장치.The switching frequency output from the PWM switching control unit is a power conversion device by fault tolerance PWM switching, characterized in that determined in accordance with the hysteresis width.
  7. 제 6항에 있어서,The method of claim 6,
    상기 히스테리시스폭이 좁으면 스위칭 주파수가 증가하고, 상기 히스테리시스폭이 넓으면 스위칭 주파수가 감소하는 것을 특징으로 하는 고장 감내형 PWM 스위칭에 의한 전력변환장치.The switching frequency increases when the hysteresis width is narrow, and the switching frequency decreases when the hysteresis width is wide.
  8. 제 1항에 있어서,The method of claim 1,
    상기 LC 필터부의 출력 양단의 부하 전압을 감지하는 전압 센서부를 더 포함하는 것을 특징으로 하는 고장 감내형 PWM 스위칭에 의한 전력변환장치.And a voltage sensor unit for detecting a load voltage across the output of the LC filter unit.
  9. 인버터 스위칭부의 출력단의 전류 및 LC 필터부 출력단의 전압을 검출하는 단계와;Detecting a current at the output of the inverter switching unit and a voltage at the output of the LC filter unit;
    상기 검출된 전류값을 절대값으로 변환한 후 기 설정된 전류값과 비교하여 그에 대응하는 CL 신호를 출력하는 단계와;Converting the detected current value into an absolute value and comparing the current value with a preset current value to output a CL signal corresponding thereto;
    상기 출력되는 CL 신호를 입력받아 상기 인버터 스위칭부의 스위치 온/오프 동작을 제어하는 단계와;Controlling the switch on / off operation of the inverter switching unit by receiving the output CL signal;
    상기 스위칭 동작의 온/오프 제어에 따라 상기 인버터 스위칭부의 전류 및 전압을 조절하는 단계를 포함하는 것을 특징으로 하는 고장 감내형 PWM 스위칭에 의한 전력변환장치의 제어방법.And controlling the current and voltage of the inverter switching unit according to the on / off control of the switching operation.
  10. 제 9항에 있어서,The method of claim 9,
    상기 CL 신호를 출력하는 단계에서 절대값으로 변환된 전류값이 기 설정된 상한 전류값보다 작으면 CL 신호는 하이(high)로 출력되고, 절대값으로 변환된 전류값이 기 설정된 상한 전류값보다 크면 CL 신호는 로우(low)로 출력되는 것을 특징으로 하는 고장 감내형 PWM 스위칭에 의한 전력변환장치의 제어방법.In the step of outputting the CL signal, if the current value converted to the absolute value is smaller than the preset upper limit current value, the CL signal is output high, and if the current value converted to the absolute value is greater than the preset upper limit current value, CL signal is low (low) output power control method of the power converter by fault-tolerant PWM switching.
  11. 제 10항에 있어서,The method of claim 10,
    상기 CL 신호가 하이(high)로 출력되면 인버터 스위칭부를 온(ON)시키고, CL 신호가 로우(low)로 출력되면 인버터 스위칭부를 오프(OFF)시키는 것을 특징으로 하는 고장 감내형 PWM 스위칭에 의한 전력변환장치의 제어방법.When the CL signal is outputted high, the inverter switching unit is turned on. When the CL signal is outputted low, the inverter switching unit is turned off. Control method of inverter.
  12. 제 9항에 있어서,The method of claim 9,
    상기 LC 필터부의 출력단 부하전압을 검출하여 기준 정현파 전압으로 제어하는 단계와;Detecting a load voltage of the output stage of the LC filter unit and controlling the load voltage to a reference sine wave voltage;
    상기 기준 정현파 전압의 스위칭 주파수를 갖는 비교 삼각파를 입력받아 인버터 스위칭부에 펄스 폭 구동 신호를 출력하는 단계를 더 포함하는 것을 특징으로 하는 고장 감내형 PWM 스위칭에 의한 전력변환장치의 제어방법.And receiving a comparison triangular wave having a switching frequency of the reference sinusoidal voltage and outputting a pulse width driving signal to an inverter switching unit.
  13. 제 12항에 있어서,The method of claim 12,
    상기 스위칭 주파수는 히스테리시스 폭에 대응하여 히스테리시스폭이 좁으면 스위칭 주파수가 증가하고, 히스테리시스폭이 넓으면 스위칭 주파수가 감소하는 것을 특징으로 하는 고장 감내형 PWM 스위칭에 의한 전력변환장치.The switching frequency corresponds to the hysteresis width, the switching frequency is increased when the hysteresis width is narrow, the switching frequency is reduced when the hysteresis width is wide, the power conversion device by fault tolerance PWM switching.
PCT/KR2013/010302 2012-11-13 2013-11-13 Apparatus for converting power by means of fault-tolerant pwm switching and method for controlling same WO2014077586A1 (en)

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