JP2004198273A - Quality check method for ac power input into power converter - Google Patents

Quality check method for ac power input into power converter Download PDF

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Publication number
JP2004198273A
JP2004198273A JP2002367639A JP2002367639A JP2004198273A JP 2004198273 A JP2004198273 A JP 2004198273A JP 2002367639 A JP2002367639 A JP 2002367639A JP 2002367639 A JP2002367639 A JP 2002367639A JP 2004198273 A JP2004198273 A JP 2004198273A
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Prior art keywords
frequency
degree
power
quality
power input
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Japanese (ja)
Inventor
Naoki Kanazawa
直樹 金沢
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Fuji Electric FA Components and Systems Co Ltd
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Fuji Electric FA Components and Systems Co Ltd
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Abstract

<P>PROBLEM TO BE SOLVED: To display a degree of separation from a set value of 3σ obtained by processing statistically a frequency count value of an alternating current power source to be alarmed, to display a voltage distortion rate and an occupation rate of higher harmonics, and to make the quality of the power source clear. <P>SOLUTION: A frequency of alternating current power input into the electric power source is formed into a data at random, a frequency data is stored in a memory, then the frequency data is processed statistically to find a frequency average μ and a dispersion σ<SP>2</SP>and a standard deviation σ and to display them, and an alarm is issued when the 3σ gets worse than a planned value. A voltage of an alternating current power input into the converter is sampled in a prescribed sampling period and a prescribed number is stored in the memory to be fast-Fourier-transformed, and the distortion rate of the input alternating current power is found to be displayed, based on an amplitude of the average μ provided hereinbefore and amplitudes of third degree, 5-th degree, 7-th degree, 11-th degree, 13-th degree, etc. higher harmonics thereof. The occupation rate of the odd numbered higher harmonics of the input alternating current power is also found to be displayed, based on the amplitude of the average μ provided hereinbefore and the amplitudes of third degree, 5-th degree, 7-th degree, 11-th degree. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【0001】
【発明の属する技術分野】
この発明は、電力変換装置へ入力する交流電力の周波数や電圧歪み率などを求めて表示や警告を行うことができる電力変換装置へ入力する交流電力の品質チェック方法に関する。
【0002】
【従来の技術】
電力変換装置として、これへ入力する交流電力を所望の電圧と周波数の交流電力に変換するインバータ装置,交流電力を所望の電圧の直流電力に変換するコンバータ,交流電源の高調波を低減するためのアクティブフィルタなど各種の電力変換装置があるが、これらの電力変換装置へ入力する交流電力の電圧や周波数などが安定していることや、その波形に歪みが無いこと等が望まれているが、僻地のように電力事情が良好でない地域,離島のように小容量のエンジン発電機が電源になっているような土地,あるいは自家用発電設備が電源になっている場合は、交流電源の電圧や周波数が変動するなど、電力の品質が不安定になることが多い。そこでこのような地域で使用する電力変換装置は、予めこのような変動に耐えられるように構成することになるが、それでも急激な変動や大きな変化には対応することができなくて、装置を停止せざるを得ないこともあった。
【0003】
【発明が解決しようとする課題】
ところで交流電源の品質は、極めて短い周期で変化する場合もあるが、日単位や週単位,あるいは月単位などの長い周期で変化する場合も多い。それ故、例えばインバータ装置を設置した当初は電源の品質が良好であったために円滑に運転していたものが、しばらくしてから電源品質の低下が原因で装置がしばしば停止する不具合を生じることがある。例えば、インバータ装置へ入力する交流電力の周波数許容範囲を60Hz± 2Hzに定めている場合は、周波数が58Hzを下回れば装置は停止となる。しかし離島のエンジン発電機に大きな負荷が加わったために、周波数が常時59Hzで運転している場合は、 1Hzの低下により周波数が58Hzを下回ることはしばしば発生するであろうし、その度にインバータ装置が停止となるような不具合を生じることになる。
【0004】
前述の不具合に対しては、周波数許容範囲を59Hz± 2Hzに変更するほうが、現地の事情に適合して望ましい。すなわち従来は、予め定めた基準周波数からの周波数の乖離の程度で電源品質の良否を判定してしまっているが、それよりも現実の周波数の平均値がいくらであるかを見極め、そこからの乖離の程度を定めて周波数の良否を判定するのが望ましいのであるが、インバータ装置は一般にこのような電源品質のチェック機能を備えていなかった。それ故、あまり問題にしなくても良いような変動であっても、電源異常と判断して当該装置をしばしば停止させてしまうような不具合を生じていた。しかもこの停止の理由が、供給される交流電力の品質不良(電圧や周波数の低下や変動)が原因であるのに、インバータ装置が不良であるためと見なされてしまう恐れもあった。
【0005】
また、パルス幅変調制御により交流電力を直流電力に変換するPWMコンバータやアクティブフィルタは、交流電源の高調波を抑制することができるが、高速サンプリングでデータを取得し、これを高速フーリエ変換処理をするのに適したハードウエアが存在しなかったこともあって、これらの高調波抑制機能がどの程度に効果を挙げているかを、装置自身がリアルタイムで表示する機能を備えていなかった。よって、従来は高調波抑制機能を計測するために、別途に測定装置を設置する必要があって不便であった。
そこでこの発明の目的は、交流電源の周波数カウント値を統計処理して得られる3σ値の設定値からの乖離の程度を表示・警報すると共に、電圧歪み率と高調波の占有率を表示し、電源の品質を明らかにすることにある。
【0006】
【課題を解決するための手段】
前記の目的を達成するために、この発明の電力変換装置へ入力する交流電力の品質チェック方法は、
電力変換装置へ入力する交流電力の周波数を無作為でデータ化し、この周波数データをメモリに記憶したのち、この周波数データを統計処理して周波数平均μと分散σ2 と標準偏差σを求めて表示する。
周波数データの統計処理で得られる前記標準偏差σの3倍値が、予め定めた値よりも悪化すれば警報を発する。
【0007】
電力変換装置へ入力する交流電力の電圧を予め定めたサンプル周期でサンプリングを行って所定数をメモリに記憶し、これらを高速フーリエ変換し、請求項1に記載の電力変換装置へ入力する交流電力の品質チェック方法によって得られる周波数平均μの振幅と当該周波数平均μの3次,5次,7次,11次,13次,17次・・・高調波の振幅から前記入力交流電圧の歪み率を求めて表示する。
前記周波数平均μの振幅と当該周波数平均μの3次,5次,7次,11次,13次,17次・・・高調波の振幅から、前記入力交流電圧の各奇数次高調波の占有率を求めて表示する。
【0008】
【発明の実施の形態】
図1は本発明の実施例を表した主回路接続図であって、インバータ装置の一部分を三相回路で表している。すなわち、ダイオードと半導体スイッチ素子との逆並列接続でなるスイッチング回路を三相ブリッジ接続してコンバータ6を構成し、交流電源1からの三相交流電力を電源スイッチ2とリアクトル3を介してコンバータ6へ与える。コンバータ6は例えばパルス幅変調制御により交流電力を直流電力に変換して直流中間回路へ出力するが、この直流電力に含まれているリプル分を抑制するために、大容量の平滑コンデンサ7を備えている。電源スイッチ2をオンにしてこのインバータ装置を始動する際に、平滑コンデンサ7に過大な充電電流が突入するのを防ぐために、充電抵抗4とこれを短絡する短絡スイッチ5を、コンバータ6の交流入力側に設置する。
【0009】
交流電源1の電圧VS (図1では相電圧を検出しているが、線間電圧であっても差し支えない)を分圧抵抗11で検出する。制御ハードウエア10は、絶縁検出器12とローパスフィルタ(以下ではLPFと略記)13と零点検出コンパレータ14とA/D変換器15,16およびCPU17で構成している。
零点検出コンパレータ14が検出する交流電圧VS の零点通過時点から、CPU17は当該交流電圧VS の1サイクルの時間を計測する。この逆数が周波数データ(h1 ,h2 ,h3 ・・・・hn )である。特定数の母集団(n個)に対して、下記の数式1により平均値μを計算し、数式2により分散σ2 を計算する。但しnは標本数である。
【0010】
【数1】

Figure 2004198273
【0011】
【数2】
Figure 2004198273
これら、数式1で得られる周波数平均値μと、数式2で得られる分散σ2 と、この分散σ2 の平方根である標準偏差σとが、本発明の第1項に対応して表示される。
標本数が十分に多ければ、周波数は正規分布で近似できるから、数式3に示す確率密度h(x) に従う。
【0012】
【数3】
Figure 2004198273
周波数は正規分布しているものと仮定しているから、この周波数分布に99.73 %の確率で取得データが入る範囲である3σ(標準偏差σの3倍)を判定の基準にする。
本発明の第2項では、例えばa,b,c,dなる4つの値を定めておき、これらの大小関係がa<b<c<dであるとすると、電源の品質レベルを下記の5つに分類することができる。すなわち、
第1分類は、3σ<a(単位HZ )のときであって、電源は最良レベルの品質である。
【0013】
第2分類は、a(単位HZ )<3σ<b(単位HZ )のときであって、電源は標準レベルの品質である。
第3分類は、b(単位HZ )<3σ<c(単位HZ )のときであって、電源は不安定レベルの品質である。
第4分類は、c(単位HZ )<3σ<d(単位HZ )のときであって、電源は要注意レベルの品質であり、異常を予報する信号を出力する。
第5分類は、d(単位HZ )<3σのときであって、電源は警報レベルの品質であり、警報を発して装置を強制停止させる。
【0014】
図2は電源が最良レベルの品質(第1分類)でa=0.5HZ のときの周波数の分布を表したグラフである。但し周波数平均値μ=49.5HZ とする。
図3は電源が警報レベルの品質(第5分類)でd=5HZ のときの周波数の分布を表したグラフである。但し周波数平均値μ=49.5HZ とする。
図1に図示の第1実施例回路におけるA/D変換器15でサンプルされたデータを高速フーリエ変換(FFT)処理を行うために、2n 個(例えば256,512,1024・・・)をメモリする。ここで多くのメモリを使用すれば高い精度の値が得られるが、そのためには大きな計算能力と計算時間とが必要になる。
よって精度と計算能力のいずれを優先させるかでメモリ数が決定されることになる。
【0015】
前述した数式1により得られる基本波周波数の振幅をf1 とし、基本波周波数の3次,5次,7次,11次,・・・高調波成分の振幅をそれぞれf3 ,f5 ,f7 ,f11,・・・とするとき、電源電圧の歪み率εは下記の数式4により計算し、本発明の第3項に対応してその計算結果を表示する。但し計算を簡略化するために、高次数成分は省略することも可能である。
【0016】
【数4】
Figure 2004198273
更に本発明の第4項に対応するものとして、3次,5次,7次,11次・・・高調波成分の基本波周波数に対する占有率をそれぞれε3 ,ε5 ,ε7 ,ε11・・・とすると、これらは下記の各数式で表示される。
【0017】
【数5】
ε3 =f3 /f1
【0018】
【数6】
ε5 =f5 /f1
【0019】
【数7】
ε7 =f7 /f1
【0020】
【数8】
ε11=f11/f1
【0021】
【発明の効果】
従来の電源は、例えば周波数の定常運転値が定格値から常に一定量ずれた状態で運転している場合は、この定常運転値から僅かに変動しただけでも、定格値からの乖離が大なために故障と判定されてしまう不具合を生じていた。これは電源の電圧や周波数が定格値からどれだけ乖離したかを検出し、その乖離の程度の大小のみで電源品質の良否を判定するのみであったからである。
本発明は、交流電源の周波数カウント値を統計処理することで、標準偏差σの3倍値を求め、これの設定値からの乖離の程度を表示し、且つ乖離の程度が大のときに警報すると共に、電圧歪み率と高調波の占有率を表示することで電源の品質が明らかになるから、機器側の不良と電源側の不良とを明確に区別することができて、対策や処置を的確に施すことができる効果が得られる。
【図面の簡単な説明】
【図1】本発明の実施例を表した主回路接続図
【図2】電源が最良レベルの品質(第1分類)でa=0.5HZ のときの周波数の分布を表したグラフ
【図3】電源が警報レベルの品質(第5分類)でd=5HZ のときの周波数の分布を表したグラフ
【符号の説明】
1 交流電源
6 コンバータ
10 制御ハードウエア
11 分圧抵抗
12 絶縁検出器
13 LPF
14 零点検出コンパレータ
15,16 A/D変換器
17 CPU17[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for checking the quality of AC power input to a power conversion device, which can display and warn by obtaining the frequency and voltage distortion rate of AC power input to the power conversion device.
[0002]
[Prior art]
As a power conversion device, an inverter device for converting AC power input thereto into AC power of a desired voltage and frequency, a converter for converting AC power to DC power of a desired voltage, and a device for reducing harmonics of an AC power source There are various types of power converters such as active filters, but it is desired that the voltage and frequency of AC power input to these power converters be stable and that their waveforms have no distortion. In areas where the power situation is not favorable, such as remote areas, on land, such as remote islands, where a small-capacity engine generator is used as a power source, or when private power generation equipment is used as the power source, the voltage and frequency of the AC power supply The power quality often becomes unstable, for example, fluctuating. Therefore, power converters used in such areas will be configured in advance to withstand such fluctuations, but still cannot respond to sudden fluctuations or large changes, and the equipment will be shut down. Sometimes I had to do it.
[0003]
[Problems to be solved by the invention]
By the way, the quality of an AC power supply sometimes changes in a very short cycle, but often changes in a long cycle such as a day, a week, or a month. Therefore, for example, when the inverter device was initially installed, it was running smoothly due to the good quality of the power supply, but after a while, the device often stopped due to the deterioration of the power supply quality. is there. For example, if the allowable frequency range of the AC power input to the inverter device is set to 60 Hz ± 2 Hz, the device stops if the frequency falls below 58 Hz. However, if the frequency is constantly operating at 59 Hz due to the heavy load applied to the engine generator on the remote island, the frequency will often drop below 58 Hz due to the 1 Hz drop, and each time the inverter device is This causes a problem such as a stop.
[0004]
For the above-mentioned problems, it is desirable to change the allowable frequency range to 59 Hz ± 2 Hz, in accordance with local circumstances. That is, in the past, the quality of the power supply was judged based on the degree of deviation of the frequency from a predetermined reference frequency.However, the average value of the actual frequency was determined more than that, and the It is desirable to determine the quality of the frequency by determining the degree of the deviation, but the inverter device generally does not have such a power quality check function. Therefore, even if the fluctuation does not need to cause much problem, there is a problem that the power supply is determined to be abnormal and the device is frequently stopped. In addition, although the reason for the stoppage is caused by the poor quality of the supplied AC power (reduction or fluctuation of the voltage or frequency), there is a risk that the inverter device may be considered to be defective.
[0005]
In addition, a PWM converter or an active filter that converts AC power into DC power by pulse width modulation control can suppress harmonics of the AC power supply, but obtains data by high-speed sampling and converts the data into high-speed Fourier transform processing. Because there was no hardware suitable for performing such a function, the apparatus itself did not have a function for displaying in real time how effective these harmonic suppression functions were. Therefore, conventionally, in order to measure the harmonic suppression function, it is necessary to separately install a measuring device, which is inconvenient.
Therefore, an object of the present invention is to display and warn the degree of deviation from the set value of the 3σ value obtained by statistically processing the frequency count value of the AC power supply, and to display the voltage distortion rate and the occupancy rate of harmonics, The purpose is to determine the quality of the power supply.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, a method for checking the quality of AC power input to the power converter of the present invention includes:
The frequency of the AC power input to the power converter is randomly converted to data, and the frequency data is stored in a memory.Then, the frequency data is statistically processed to obtain and display a frequency average μ, a variance σ 2 and a standard deviation σ. I do.
When the triple value of the standard deviation σ obtained by the statistical processing of the frequency data becomes worse than a predetermined value, an alarm is issued.
[0007]
2. The AC power input to the power converter according to claim 1, wherein a voltage of the AC power input to the power converter is sampled at a predetermined sampling period, a predetermined number is stored in a memory, and these are subjected to fast Fourier transform. From the amplitude of the frequency average μ obtained by the quality check method and the amplitudes of the third, fifth, seventh, eleventh, thirteenth, seventeenth,... Harmonics of the frequency average μ. Is displayed.
From the amplitude of the frequency average μ and the amplitudes of the third, fifth, seventh, eleventh, thirteenth, seventeenth,... Harmonics of the frequency average μ, the occupation of each odd harmonic of the input AC voltage Find and display the rate.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a main circuit connection diagram showing an embodiment of the present invention, in which a part of an inverter device is represented by a three-phase circuit. That is, a switching circuit composed of an antiparallel connection of a diode and a semiconductor switching element is connected in a three-phase bridge to form a converter 6, and the three-phase AC power from the AC power supply 1 is supplied to the converter 6 via the power switch 2 and the reactor 3. Give to. The converter 6 converts AC power into DC power by, for example, pulse width modulation control and outputs the DC power to a DC intermediate circuit. In order to suppress ripples contained in the DC power, the converter 6 includes a large-capacity smoothing capacitor 7. ing. When the power switch 2 is turned on to start the inverter device, the charging resistor 4 and the short-circuit switch 5 for short-circuiting the charging resistor 4 are connected to the AC input of the converter 6 in order to prevent an excessive charging current from flowing into the smoothing capacitor 7. Install on the side.
[0009]
The voltage V S of the AC power supply 1 (the phase voltage is detected in FIG. 1, but it may be a line voltage) is detected by the voltage dividing resistor 11. The control hardware 10 includes an insulation detector 12, a low-pass filter (hereinafter abbreviated as LPF) 13, a zero point detection comparator 14, A / D converters 15 and 16, and a CPU 17.
The CPU 17 measures the time of one cycle of the AC voltage V S from the time when the AC voltage V S detected by the zero point detection comparator 14 passes through the zero point. This reciprocal is the frequency data (h 1 , h 2 , h 3 ... H n ). For a specific number of populations (n), the average value μ is calculated by the following equation 1, and the variance σ 2 is calculated by the following equation 2. Here, n is the number of samples.
[0010]
(Equation 1)
Figure 2004198273
[0011]
(Equation 2)
Figure 2004198273
The frequency average value μ obtained by Expression 1, the variance σ 2 obtained by Expression 2, and the standard deviation σ which is the square root of the variance σ 2 are displayed corresponding to the first term of the present invention. .
If the number of samples is sufficiently large, the frequency can be approximated by a normal distribution, and therefore follows the probability density h (x) shown in Expression 3.
[0012]
[Equation 3]
Figure 2004198273
Since it is assumed that the frequencies are normally distributed, 3σ (three times the standard deviation σ), which is a range in which the acquired data enters the frequency distribution with a probability of 99.73%, is used as a criterion for determination.
In the second term of the present invention, for example, four values a, b, c, and d are defined, and if these magnitude relations are a <b <c <d, the quality level of the power supply is set to the following 5: Can be classified into one. That is,
The first category is when 3σ <a (unit H Z ) and the power supply is of the best quality.
[0013]
The second classification is effected even if the a (unit H Z) <3σ <b (unit H Z), the power source is a quality standard level.
The third classification is effected even if b (unit H Z) <3σ <c (unit H Z), the power source is a quality of the unstable level.
The fourth classification, there is time of c (unit H Z) <3σ <d (unit H Z), the power has quality caution level, and outputs a signal for forecasting an abnormality.
The fifth category is when d (unit H Z ) <3σ, and the power source is of an alarm level quality, which issues an alarm and forcibly shuts down the device.
[0014]
Figure 2 is a graph showing the distribution of frequencies when the power quality of the best level (first classification) a = 0.5H Z. However the frequency mean value μ = 49.5H Z.
Figure 3 is a graph showing the distribution of frequency when the quality of the power supply alarm level (fifth classification) d = 5H Z. However the frequency mean value μ = 49.5H Z.
In order to perform fast Fourier transform (FFT) processing on the data sampled by the A / D converter 15 in the circuit of the first embodiment shown in FIG. 1, 2 n (for example, 256, 512, 1024...) Memory. If a large amount of memory is used here, a high-accuracy value can be obtained, but this requires a large calculation capability and calculation time.
Therefore, the number of memories is determined by giving priority to accuracy or calculation ability.
[0015]
The amplitude of the fundamental frequency obtained by Equation 1 described above and f 1, 3-order fundamental wave frequency, fifth, seventh, 11th, the amplitude of ... harmonic components respectively f 3, f 5, f .. , F 11 ,..., The distortion rate ε of the power supply voltage is calculated by the following equation 4, and the calculation result is displayed corresponding to the third term of the present invention. However, in order to simplify the calculation, the higher-order components can be omitted.
[0016]
(Equation 4)
Figure 2004198273
Further, as corresponding to the fourth term of the present invention, the occupancy rates of the third, fifth, seventh, eleventh,... Harmonic components with respect to the fundamental frequency are set to ε 3 , ε 5 , ε 7 , ε 11, respectively. ..., these are represented by the following equations.
[0017]
(Equation 5)
ε 3 = f 3 / f 1
[0018]
(Equation 6)
ε 5 = f 5 / f 1
[0019]
(Equation 7)
ε 7 = f 7 / f 1
[0020]
(Equation 8)
ε 11 = f 11 / f 1
[0021]
【The invention's effect】
For example, if the conventional power supply is operated in a state in which the steady-state operating value of the frequency always deviates from the rated value by a constant amount, even if it slightly fluctuates from the steady-state operating value, the deviation from the rated value is large. Had a problem of being determined to be a failure. This is because it is only necessary to detect how much the voltage and frequency of the power supply deviate from the rated value, and to judge the quality of the power supply only based on the magnitude of the deviation.
The present invention obtains a triple value of the standard deviation σ by statistically processing the frequency count value of the AC power supply, displays the degree of deviation from the set value, and issues an alarm when the degree of deviation is large. In addition, since the quality of the power supply is clarified by displaying the voltage distortion rate and the occupancy rate of the harmonics, it is possible to clearly distinguish the failure on the device side from the failure on the power supply side, and to take measures and measures. An effect that can be applied accurately can be obtained.
[Brief description of the drawings]
Graph Figure showing the distribution of frequency when embodiments the main circuit connection diagram Figure 2 showing the power quality of the best level (first classification) a = 0.5H Z Next Patent 3] graph description [code showing the distribution of frequency when the quality of the power supply alarm level (fifth classification) d = 5H Z]
DESCRIPTION OF SYMBOLS 1 AC power supply 6 Converter 10 Control hardware 11 Voltage dividing resistor 12 Insulation detector 13 LPF
14 Zero detection comparators 15 and 16 A / D converter 17 CPU 17

Claims (4)

電力変換装置へ入力する交流電力の周波数を無作為でデータ化し、この周波数データをメモリに記憶したのち、この周波数データを統計処理して周波数平均μと分散σ2 と標準偏差σを求め、これらを表示することを特徴とする電力変換装置へ入力する交流電力の品質チェック方法。Into data at random the frequency of the AC power input to the power converter, this after the frequency data stored in the memory, obtains the frequency mean μ variance sigma 2 and the standard deviation sigma by statistically processing the frequency data, these Is displayed, and a method for checking the quality of the AC power input to the power converter. 請求項1に記載の電力変換装置へ入力する交流電力の品質チェック方法において、
前記周波数データの統計処理で得られる標準偏差σの3倍値が、予め定めた値よりも悪化すれば警報を発することを特徴とする電力変換装置へ入力する交流電力の品質チェック方法。
A method for checking the quality of AC power input to the power converter according to claim 1,
A method for checking the quality of AC power input to a power converter, wherein an alarm is issued when a value three times the standard deviation σ obtained by the statistical processing of the frequency data becomes worse than a predetermined value.
電力変換装置へ入力する交流電力の電圧を予め定めたサンプル周期でサンプリングを行って所定数をメモリに記憶し、これらを高速フーリエ変換し、請求項1に記載の電力変換装置へ入力する交流電力の品質チェック方法によって得られる周波数平均μの振幅と当該周波数平均μの3次,5次,7次,11次,13次,17次・・・高調波の振幅から前記入力交流電圧の歪み率を求め、これを表示することを特徴とする電力変換装置へ入力する交流電力の品質チェック方法。2. The AC power input to the power converter according to claim 1, wherein a voltage of the AC power input to the power converter is sampled at a predetermined sampling period, a predetermined number is stored in a memory, and these are subjected to fast Fourier transform. From the amplitude of the frequency average μ obtained by the quality check method and the amplitudes of the third, fifth, seventh, eleventh, thirteenth, seventeenth,... Harmonics of the frequency average μ. And checking the quality of the AC power input to the power converter. 請求項3に記載の電力変換装置へ入力する交流電力の品質チェック方法において、
前記周波数平均μの振幅と当該周波数平均μの3次,5次,7次,11次,13次,17次・・・高調波の振幅から、前記入力交流電圧の各数次高調波の占有率を求めて表示することを特徴とする電力変換装置へ入力する交流電力の品質チェック方法。
A method for checking the quality of AC power input to a power converter according to claim 3,
Based on the amplitude of the frequency average μ and the amplitudes of the third, fifth, seventh, eleventh, thirteenth, seventeenth,... Harmonics of the frequency average μ, the occupation of each of the several harmonics of the input AC voltage A method for checking the quality of AC power input to a power converter, wherein the rate is obtained and displayed.
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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100668959B1 (en) 2004-10-30 2007-01-12 한국전력공사 The remote terminal unit for distribution automation that can be monitored electrical quality on realtime in distribution network
JP2008139225A (en) * 2006-12-05 2008-06-19 Yokogawa Electric Corp Spectrum display device and fourier analyzer using it
KR101035702B1 (en) 2010-06-29 2011-05-19 한국전력공사 Apparatus and method for measuring the power quality
WO2012002615A1 (en) * 2010-06-30 2012-01-05 한국전력공사 Power quality monitoring system and method thereof
JP5826955B1 (en) * 2015-01-29 2015-12-02 根岸 正子 Low voltage circuit diagnosis system and program

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100668959B1 (en) 2004-10-30 2007-01-12 한국전력공사 The remote terminal unit for distribution automation that can be monitored electrical quality on realtime in distribution network
JP2008139225A (en) * 2006-12-05 2008-06-19 Yokogawa Electric Corp Spectrum display device and fourier analyzer using it
KR101035702B1 (en) 2010-06-29 2011-05-19 한국전력공사 Apparatus and method for measuring the power quality
WO2012002617A1 (en) * 2010-06-29 2012-01-05 한국전력공사 Power quality measuring device and method
WO2012002615A1 (en) * 2010-06-30 2012-01-05 한국전력공사 Power quality monitoring system and method thereof
KR101144276B1 (en) 2010-06-30 2012-05-11 한국전력공사 Power quality monitoring system and method thereof
JP5826955B1 (en) * 2015-01-29 2015-12-02 根岸 正子 Low voltage circuit diagnosis system and program
JP2016138861A (en) * 2015-01-29 2016-08-04 根岸 正子 Low-voltage circuit diagnostic system and program

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