JP2014016368A - Synchronization detection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a synchronization detection method in which single phase AC voltage is not differentiated directly, which is made less susceptible to an influence of higher harmonic component, in which a case of dividing by zero is eliminated, and is made less likely to become unstable.SOLUTION: A synchronization detection device 130 which implements a synchronization detection method of the present invention, includes: a standard angular frequency ω; a sampler 133 which detects a detection target voltage waveform of a detection target single phase AC voltage source 12; a delay circuit 134 which generates a delayed voltage waveform by delaying time larger than (m-1)π/ωand smaller than mπ/ω(m is a natural number) from the detection target voltage waveform detected by the sampler 133; and an arithmetic unit 135 which uses the detection target voltage waveform detected by the sampler 133, the delayed voltage waveform generated by the delay circuit 134, and a detection source angular frequency ω of a given detection source single phase AC voltage source 11 to compute a frequency difference cosine signal and a frequency difference sine signal taking a difference between a detection target angular frequency ωof the detection target voltage waveform and the detection source angular frequency ω as an angular frequency.

Description

  The present invention relates to a synchronization verification method for detecting a voltage amplitude of a single-phase AC voltage source as a synchronization partner, a frequency difference from a self-power source, and a phase difference from the self-power source.

  In order to synchronize the two single-phase AC voltage sources, it is necessary to detect the voltage amplitude of the synchronized single-phase AC voltage source, the frequency difference with the own power source, and the phase difference with the own power source. The technique of FIG. 4 for detecting these is known.

  In this technique, for each single-phase AC voltage source, the voltage is sampled at regular intervals, and the change per sample (corresponding to the differential value) and the change per sample (2 Equivalent to the second derivative). And after calculating | requiring a voltage amplitude, a frequency, and a phase from the derived | led-out value, the difference is calculated (for example, refer patent document 1).

Japanese Patent Laid-Open No. 52-40174

  However, since the technique described in Patent Document 1 differentiates the sample voltage value, there is a problem that it is easily affected by the harmonic component included in the voltage waveform. Furthermore, since division using the AC value as the denominator is used for frequency detection, there is a problem that the frequency becomes unstable when dividing by zero.

  Therefore, in order to solve the above-described problems, an object of the present invention is to provide a synchronous verification method that is not easily affected by harmonic components and is not easily unstable.

In order to achieve the above object, the synchronization verification method according to the present invention uses a voltage waveform of a single-phase AC voltage source to be verified and a reference angular frequency ω _co of the synchronization verification device for a predetermined time. A delay voltage waveform obtained by delaying the frequency difference is created, and a frequency difference cosine signal and a frequency difference sine signal are calculated from the test target voltage waveform detected by the sampler and the delay voltage waveform. In the following explanation, the single-phase AC voltage waveform of the single-phase AC voltage source to be verified is described as “voltage waveform for verification”, and the single-phase AC voltage waveform of the single-phase AC voltage source that is the verification source is described as “verification-source voltage waveform”. To do.

Specifically, the synchronous verification method according to the present invention includes a sampling procedure for detecting a verification target voltage waveform of a verification target single-phase AC voltage source, and (m−1) from the verification target voltage waveform detected by the sampling procedure. a delay procedure for creating a delayed voltage waveform with a delayed time greater than π / ω _{co and} smaller than mπ / ω _co (m is a natural number, ω _co is a reference angular frequency), and the voltage waveform to be tested detected in the sampling procedure, The difference between the test target angular frequency of the test target voltage waveform and the test source angular frequency is calculated from the delay voltage waveform created by the delay procedure and the test source angular frequency of the given test source single-phase AC voltage source. And a calculation procedure for calculating a frequency difference cosine signal and a frequency difference sine signal as frequencies. The reference angular frequency ω _co of the synchronization verification device may be equal to the verification source angular frequency ω.

  The frequency difference cosine signal is the product of the cosine of the phase difference and the voltage amplitude to be tested, and the frequency difference sine signal is the product of the sine of the phase difference and the voltage amplitude to be tested. Using these two values, the voltage amplitude of the voltage waveform to be verified, the frequency difference from the verification source voltage waveform, and the phase difference from the verification source voltage waveform can be calculated. The synchronous verification method according to the present invention does not directly differentiate the single-phase AC voltage and does not divide by zero unless the effective value of the voltage waveform to be verified is zero. For this reason, the present invention can provide a synchronous verification method that is not easily affected by the harmonic component and is not easily unstable.

The synchronization verification method according to the present invention is characterized in that, in the delay procedure, the delay voltage waveform is delayed by (m−1 / 2) π / ω _co time from the verification target voltage waveform.

また、ωは規準角周波数ω_ｃｏの７５％から１２５％の範囲にある。 The synchronous verification method according to the present invention is characterized in that the calculation of Formula 1 is performed according to the calculation procedure.

Further, ω is in the range of 75% to 125% of the reference angular frequency ω _co .

  In the synchronization verification method according to the present invention, it is preferable to further perform a high frequency component removal procedure for removing the high frequency component of the frequency difference cosine signal and the frequency difference sine signal calculated in the calculation procedure. By removing the high frequency components of the frequency difference cosine signal and the frequency difference sine signal, the voltage amplitude of the voltage waveform to be verified, the frequency difference from the verification source voltage waveform, and the phase difference from the verification source voltage waveform are more stable. Can be calculated.

  In the synchronous verification method according to the present invention, the effective voltage value of the verification target voltage waveform, the verification target angular frequency, and the verification source angular frequency are calculated from the frequency difference cosine signal and the frequency difference sine signal calculated in the calculation procedure. And a detection procedure for detecting a phase difference between the verification target voltage waveform and the verification source single-phase AC voltage waveform. According to the detection procedure, the voltage amplitude of the verification target voltage waveform, the frequency difference from the verification source voltage waveform, and the phase difference from the verification source voltage waveform can be output.

ここで、Ｖｓは前記電圧実効値である。

ここで、ω_ｓは前記検定対象角周波数である。

In the synchronization verification method according to the present invention, the effective voltage value V _S , the frequency difference ω _S −ω, and the phase difference φ are detected by the above-described detection procedure using Equations 2, 3, and 4, respectively.

Here, Vs is the voltage effective value.

Here, ω _s is the angular frequency to be tested.

  The present invention can provide a synchronous verification method that is not easily affected by the harmonic component and is less likely to become unstable. Moreover, since the synchronous verification method according to the present invention samples the voltage waveform to be verified, it can be easily applied particularly when the verification source single-phase AC voltage source is a digital control power supply. Furthermore, the synchronous verification method according to the present invention does not require a detection unit for detecting the effective voltage value, frequency, and phase in both the verification source voltage waveform and the verification target voltage waveform as shown in FIG. is there. Moreover, the synchronous verification method according to the present invention can remove the influence of the high frequency component by the high frequency component removal procedure, and can stabilize the operation.

It is a figure explaining the synchronous test | inspection performed between a test origin single phase alternating voltage source and a test object alternating voltage source. It is a figure explaining the synchronous verification apparatus which implement | achieves the synchronous verification method which concerns on this invention. It is the result of simulating the synchronization verification operation in the synchronization verification method according to the present invention. It is a figure explaining the conventional synchronous verification apparatus.

  Embodiments of the present invention will be described with reference to the accompanying drawings. The embodiments described below are examples of the present invention, and the present invention is not limited to the following embodiments. In the present specification and drawings, the same reference numerals denote the same components.

ここで、Ｖ_ｉは検定元単相交流電圧源１１の電圧の実効値である。 First, the principle of synchronous verification will be described. FIG. 1 is a diagram for explaining the synchronization verification performed between the verification source single-phase AC voltage source 11 and the verification target AC voltage source 12. The verification source single-phase AC voltage source 11 is a single-phase AC power source including a synchronous verification device such as an inverter that performs autonomous parallel operation (APRun). The verification target single-phase AC voltage source 12 is, for example, a parallel partner power system or an external AC power source. When the test source single-phase AC voltage source 11 performs the no-load independent operation, the output terminal voltage _Vfil (t) can be expressed by the following equation.

Here, V _i is the effective value of the voltage of the test source single-phase AC voltage source 11.

ここで、Ｖ_ｓは実効値［Ｖ］、ω_ｓは角周波数［ｒａｄ／ｓ］、φはインバータから見た外部交流電源のｔ＝０での位相角［ｒａｄ］である。 On the other hand, the voltage V _sys (t) of the single-phase AC voltage source 12 to be verified can be expressed by the following equation.

Here, V _s is an effective value [V], ω _s is an angular frequency [rad / s], and φ is a phase angle [rad] at t = 0 of the external AC power source viewed from the inverter.

Ｖ^＃ _ｓｙｓ（ｔ）は次のように変形される。

Consider a waveform V ^# _sys (t) delayed by π / (2ω _co ) [s] with respect to this V _sys (t). Here, ω _co is the reference angular frequency [rad / s] of the synchronous verification device. Since ω _co does not always coincide with ω _s , V ^# _sys (t) is not necessarily delayed by exactly π / 2 with respect to V _sys (t).

V ^# _sys (t) is transformed as follows.

数９で得られるＶ_３（ｔ）及びＶ_４（ｔ）をそれぞれ周波数差余弦信号及び周波数差正弦信号と呼ぶ。 Here, V _sys (t) and V ^# _sys (t) are subjected to rotational coordinate transformation as follows using the phase angle θ _i (= ωt) of the test source single-phase AC voltage source. In this rotational coordinate conversion, V _sys (t) is rotated in the direction opposite to θ _i .

V ₃ (t) and V ₄ (t) obtained by Equation 9 are called a frequency difference cosine signal and a frequency difference sine signal, respectively.

First, consider the frequency difference cosine signal V ₃ (t).

数１１には、検定元単相交流電圧源の周波数と検定対象単相交流電圧源の周波数との和と差の周波数成分があり、その振幅は共に、

である。この振幅は、検定対象単相交流電圧源の周波数が同期検定装置の規準周波数に近ければ小さい。例えば、前者が５１Ｈｚ、後者が５０Ｈｚならば数１２の値は０．０１５７Ｖｓ［Ｖ］である。 The second term of Equation 10 can be modified as follows.

Equation 11 includes the frequency component of the sum and difference of the frequency of the verification source single-phase AC voltage source and the frequency of the verification-target single-phase AC voltage source, both of which have amplitudes,

It is. This amplitude is small if the frequency of the single-phase AC voltage source to be verified is close to the reference frequency of the synchronous verification device. For example, if the former is 51 Hz and the latter is 50 Hz, the value of Equation 12 is 0.0157 Vs [V].

となる。従って、Ｖ_３（ｔ）の和周波数成分を除去した波形をＶ_Ｕ３（ｔ）とすると、

となる。 When the waveform component of Equation 11 is removed by a low-pass filter and the sum frequency component, which is approximately twice the frequency, is removed,

It becomes. Therefore, if the waveform from which the sum frequency component of V ₃ (t) is removed is V _U3 (t),

It becomes.

From Equation 14, V _U3 (t) is the difference between the amplitude of V _s · cos (π (ω _co −ω _s ) / (4ω _co )) and the frequency of the single-phase AC voltage source to be tested and the reference frequency of the synchronous testing device. And a cosine wave whose initial phase (phase at t = 0) is φ + (π (ω _co −ω _s ) / (4ω _co )). As an example, when ω _co = 100π [rad / s] (50 Hz) and ω _s = 102π [rad / s] (51 Hz), the amplitude is 0 · 99888Vs [V], the frequency is 1 Hz, and the initial phase is φ _s +0.9 [deg].

If ω _s is close to ω _co , V _U3 (t) will be approximately equal to:

Next, consider the frequency difference sine signal V ₄ (t).

数１７には、検定元単相交流電圧源の周波数と検定対象単相交流電圧源の周波数との和と差の周波数成分があり、その振幅は共に、

である。この振幅は数１２の周波数差余弦信号Ｖ_３（ｔ）の振幅と等しくなる。 The second term of Equation 16 can be modified as follows.

Equation 17 includes frequency components of the sum and difference of the frequency of the verification source single-phase AC voltage source and the frequency of the verification-target single-phase AC voltage source,

It is. This amplitude is equal to the amplitude of the frequency difference cosine signal V ₃ (t) in Expression 12.

となる。従って、Ｖ_４（ｔ）の和周波数成分を除去した波形をＶ_Ｕ４（ｔ）とすると、

となる。 When the frequency component of the sum which is almost double frequency is removed from the waveform of Equation 17 with a low-pass filter,

It becomes. Therefore, if the waveform from which the sum frequency component of V ₄ (t) is removed is V _U4 (t),

It becomes.

From Equation 20, V _U4 (t) is the same as V _U3 (t), the amplitude is V _s · cos (π (ω _co −ω _s ) / (4ω _co )), and the frequency is the single-phase AC voltage source to be tested. It becomes a sine wave whose frequency and initial phase (phase at t = 0) are φ + (π (ω _co −ω _s ) / (4ω _co )) with respect to the difference from the verification source single-phase AC voltage source.

If ω _s is close to ω _co , V _U4 (t) will be approximately equal to:

となる。例えば、同期検定装置規準周波数が５０Ｈｚ、検定対象単相交流電源の周波数が４９Ｈｚとすると、

である。通常、商用電源の周波数変動範囲は±０．２Ｈｚ程度であるので、検定対象単相交流電源の電圧の大きさを充分正確に検出できる。 Next, a method for verifying the synchronization between the verification target single-phase AC voltage source and the verification-source single-phase AC voltage source using the frequency difference cosine signal V _U3 (t) and the frequency difference sine signal V _U4 (t) will be described. To do. {V _U3 (t)} ² + {V _U3 (t)} ²

It becomes. For example, if the synchronous verification device standard frequency is 50 Hz and the frequency of the verification target single-phase AC power supply is 49 Hz,

It is. Usually, since the frequency fluctuation range of the commercial power supply is about ± 0.2 Hz, the magnitude of the voltage of the verification target single-phase AC power supply can be detected sufficiently accurately.

数２４を数２２で割ることで周波数差を求めることができる。

Next, detection of the frequency difference will be described. Equation 24 is calculated.

The frequency difference can be obtained by dividing Expression 24 by Expression 22.

This will be described more specifically. FIG. 2 is a diagram illustrating a synchronization verification device 130 that implements the synchronization verification method of the present embodiment. The synchronization verification device 130 calculates a reference angular frequency ω _co , a sampler 133 for detecting the verification target voltage waveform of the verification target single-phase AC voltage source 12, and the verification target voltage waveform detected by the sampler 133 (m−1 / 2). ) Π / ω _co (where m is a natural number) a delay circuit 134 that creates a delayed voltage waveform delayed in time, the test target voltage waveform detected by the sampler 133, the delayed voltage waveform created by the delay circuit 134, and A frequency difference cosine signal and a frequency difference having an angular frequency as a difference between the verification target angular frequency ω _{s of the} verification target voltage waveform and the verification source angular frequency ω of the verification target single-phase AC voltage source 11. And an arithmetic unit 135 for calculating a sine signal.

In this embodiment, the synchronization verification device 130 has the reference angular frequency ω _co , but may be received from the single-phase AC voltage source 11 that is the verification source. In this case, the verification source voltage waveform V ₁ (t) of the single-phase AC voltage source 11 can be expressed by the following equation.

サンプラー１３３は、この検定対象電圧波形Ｖ_２（ｔ）をサンプリングする。ここで、検定対象電圧波形Ｖ_２（ｔ）をサンプリングしたサンプル波形をＶ_２（ｎＴｓ）と表す。Ｔｓはサンプル周期であり、ｎはサンプル番号である。 Further, the verification target voltage waveform V ₂ (t) of the single-phase AC voltage source 12 to be verified can be expressed by the following equation.

The sampler 133 samples this verification target voltage waveform V ₂ (t). Here, a sample waveform obtained by sampling the verification target voltage waveform V ₂ (t) is represented as V ₂ (nTs). Ts is a sample period, and n is a sample number.

The delay circuit 134 receives the reference angular frequency ω _co and the delay voltage waveform V ₂ ^# (nTs) delayed from the sample waveform V ₂ (nTs) by a period of (m−1 / 2) π / ω _co (m is a natural number). ).

The delay amount of the delay voltage waveform V ₂ ^# (nTs) can be expressed as (m−1 / 2) π / ω _co . In the present embodiment, a case where m = 1 (a case where a quarter cycle is delayed) will be described. In this case, the delay voltage waveform V ₂ ^# (nTs) is expressed by the following equation.

The calculation unit 135 receives the verification source angular frequency ω from the single-phase AC voltage source 11. The calculation unit 135 receives the sample waveform V ₂ (nTs) and the delay voltage waveform V ₂ ^# (nTs), and calculates the difference between the verification source angular frequency ω and the verification target angular frequency ω _s of the single-phase AC voltage source 12. A frequency difference cosine signal V ₃ (nTs) and a frequency difference sine signal V ₄ (nTs) as frequencies are calculated.

Specifically, the calculation unit 135 performs rotational coordinate conversion on the sample waveform V ₂ (nTs) and the delayed voltage waveform V ₂ ^# (nTs) as shown in Equation 1 to perform the frequency difference cosine signal V ₃ (nTs) and the frequency difference. The sine signal V ₄ (nTs) is calculated.

When the calculation unit 135 calculates, the frequency difference cosine signal V ₃ (nTs) and the frequency difference sine signal V ₄ (nTs) include a high frequency component having a frequency of (ω _s + ω). Therefore, the calculation unit 135 further includes low-pass filters (152A, 152B) that remove high-frequency components. The frequency difference cosine signal and the frequency difference sine signal from which high-frequency components have been removed by the low-pass filters (152A, 152B) are denoted as V _U3 (nTs) and V _U4 (nTs), respectively.

The synchronization verification device 130 further includes a detection unit 136. The detection unit 136 uses the frequency difference cosine signal V _U3 (nTs) and the frequency difference sine signal V _U4 (nTs) output from the calculation unit 135 to determine the effective voltage value and verification of the voltage waveform V ₂ (t) to be tested. frequency difference between the test target angular frequency omega _s test with the original angular frequency omega of the target voltage waveform V _{2 (t),} and the phase difference of the test target voltage waveform V _{2 (t)} and test the original voltage waveform V _{1 (t)} Can be detected.

Specifically, the detection unit 136 detects the voltage effective value, the frequency difference, and the phase difference with the circuit 161 that calculates the equation 2, the circuit 162 that calculates the equation 3, and the circuit 163 that calculates the equation 4, respectively. The synchronization verification device 130 may input the detected voltage effective value, frequency difference, and phase difference information to the single-phase AC voltage source 11. Based on this information, the single-phase AC voltage source 11 determines the voltage amplitude value V, the verification source angular frequency ω, and the phase of the verification source voltage waveform V1 (t) as the voltage amplitude value V _{s of} the single-phase AC voltage source 12, It can be matched with the angular frequency to be tested ω _s and the phase φ. Therefore, the single phase AC voltage source 11 can be synchronized with the single phase AC voltage source 12 by using the synchronization verification device 130 and can be connected to the single phase AC voltage source 12.

  In the description of the present embodiment, the synchronization verification device 130 is described as being outside the single-phase AC voltage source 11, but the single-phase AC voltage source 11 may include the synchronization verification device 130.

In the description of the present embodiment, the delay time of the delay circuit 134 is (m−1 / 2) π / ω _co , but the delay time is delayed by an arbitrary period except for the m period and the (m−1 / 2) period. Even in the case of the same effect can be obtained. Specifically, the delay circuit 134 delays the sample waveform V ₂ (nTs) by a period excluding (2m−1) / 2 period and m period, and generates a delayed voltage waveform V ₂ ^# (nTs). For example, the delay voltage waveform V ₂ ^# (nTs) is 1/6 period, 2/6 period, 4/6 period, 5/6 period,..., P / 6 period (p is a natural number that is not a multiple of 3). Can be delayed. Further, the delay voltage waveform V ₂ ^# (nTs) can be delayed by a quarter period, a quarter period,..., A q / 4 period (where q is an odd number).

  Further, although the coefficient of the matrix of Equation 1 is 1 / √2, it may be any value other than zero.

(Example)
FIG. 3 simulates how the synchronization verification device 130 detects the voltage amplitude V _{s of} the single-phase AC voltage source 12 and the frequency difference and phase difference between the single-phase AC voltage source 11 and the single-phase AC voltage source 12. It is a result. The reference frequency of the synchronous verification apparatus was 50 Hz (ω _co = 100π rad / s). The single-phase AC voltage source 11 is assumed to be operating at 220 V and 52 Hz. The single-phase AC voltage source 12 is assumed to be operating at 180 V (Vs) and 48 Hz (ω _co = 96π rad / s).

Frequency difference cosine signals V _U3 (nTs) and V _U4 (V _U4 (t) generated from the test target voltage waveform V ₂ (t) of the single-phase AC voltage source 12 and the delayed voltage waveform V ₂ ^# (t) delayed by 0.25 cycle. nTs) has an amplitude of 180 V (the voltage effective value of the single-phase AC voltage source 12) and a frequency of 4 Hz (the frequency of the difference between the frequency of the verification source voltage waveform and the frequency of the verification target voltage waveform).

  The detection unit 136 detects the effective voltage value as 180 V, and is equal to the effective voltage value of the single-phase AC voltage source 12. The detection unit 136 detects a frequency difference of −4 Hz, and the frequency difference between the set single-phase AC voltage source 11 and the single-phase AC voltage source 12 (the single-phase AC voltage source 12 is different from the single-phase AC voltage source 11). Equal to the frequency difference). The detection unit 136 can also detect a phase difference caused by a frequency difference.

  As described in the present embodiment, the synchronous verification device 130 includes the voltage effective value of the single-phase AC voltage source 12, the frequency difference between the single-phase AC voltage source 11 and the single-phase AC voltage source 12, and the single-phase AC voltage source. 11 and the single-phase AC voltage source 12 can be accurately detected.

11, 12: Single-phase AC voltage source 130: Synchronous verification device 133: Sampler 134: Delay circuit 135: Calculation unit 136: Detection unit 151: Rotation coordinate conversion circuit 152A, 152B: Low-pass filter 153: Frequency difference cosine signal output terminal 154 : Frequency difference sine signal output terminals 161, 162, 163: Circuit

Claims (6)

A sampling procedure for detecting a voltage waveform to be verified of a single-phase AC voltage source to be verified;
The sampling procedure the detected in the assay target from the voltage waveform (m-1) greater than π / ω _co mπ / ω _co smaller (m is a natural number, omega _co the reference angular frequency) generates a delay voltage waveform delayed time A delay procedure to
The verification target angle of the verification target voltage waveform from the verification target voltage waveform detected by the sampling procedure, the delayed voltage waveform created by the delay procedure, and the verification source angular frequency of a given verification source single-phase AC voltage source A calculation procedure for calculating a frequency difference cosine signal and a frequency difference sine signal in which the difference between the frequency and the test source angular frequency is an angular frequency;
Synchronous verification method. 2. The synchronous verification method according to claim 1, wherein the delay voltage waveform is delayed by (m−1 / 2) π / ω _co time from the verification target voltage waveform in the delay procedure. The synchronous test method according to claim 2, wherein the mathematical procedure is performed in the calculation procedure.

Further, ω is in the range of 75% to 125% of the reference angular frequency ω _co .   The synchronous test method according to any one of claims 1 to 3, further comprising a high-frequency component removal procedure for removing the high-frequency component of the frequency difference cosine signal and the frequency difference sine signal calculated in the calculation procedure.   From the frequency difference cosine signal and the frequency difference sine signal calculated in the calculation procedure, the voltage effective value of the verification target voltage waveform, the frequency difference between the verification target angular frequency and the verification source angular frequency, and the verification target voltage 5. The synchronous verification method according to claim 1, further comprising a detection procedure for detecting a phase difference between a waveform and the verification source single-phase AC voltage waveform. 6. The voltage effective value V _S , the frequency difference ω _S −ω, and the phase difference φ are detected by Equation 2, Equation 3, and Equation 4, respectively, in the detection procedure. Synchronous verification method.

Here, Vs is the voltage effective value.

Here, ω _s is the angular frequency to be tested.

Images