JP2020187043A - Parameter calculation device, parameter calculation method, and electric quantity measuring device - Google Patents

Abstract

To calculate parameters of a sinusoidal signal to be measured by waveform data for a 1/4 cycle.SOLUTION: A parameter calculation device calculates a correlation coefficient rφ1 of a signal x,yφ1 and a correlation coefficient rφ2 of a signal x, yφ2 from waveform data Dw for a 1/4 cycle of a sinusoidal signal x(=Asin(2πft)+M) to be measured and each reference waveform data Drw1, Drw2 for the 1/4 cycle of a reference sinusoidal signal yφ1(=Bsin(2πft+φ1)+N), yφ2(=Bsin(2πft+φ2)+N), calculates a temporary initial phase θx from rφ1=(Dcos(θ-φ1)-Csin(θ+φ1))/(√(D-Csin2θ)√(D-Csin2 φ1)), calculates an initial phase θ from the θx by a conversion expression associated with a combination of polarities of the coefficients rφ1, rφ2, and calculates parameters A, M from Dwa=Asin(ψa+θ)+M and Dwb=Asin(ψb+θ)+M defined by the θ, waveform data Dwa, Dwb and phase differences ψa, ψb.SELECTED DRAWING: Figure 1

Description

The present invention relates to a parameter calculation device and a parameter calculation method for calculating this parameter for a measured sinusoidal signal whose parameters such as amplitude and initial phase are unknown, and an electric quantity measuring device having this parameter calculation device.

In the impedance measuring device for measuring impedance as the amount of electricity in this type of electric quantity measuring device, for example, a frequency characteristic analyzer disclosed as a background technique in Patent Document 1 below (frequency characteristic provided with a two-phase synchronous detector). An analyzer) is commonly used to measure the impedance of the electrical component to be measured, including the phase.

This impedance measuring device has a voltage across the measurement target (Vv: Av × sin (ωt + Bv) + Cv) measured while a sine wave signal is applied to the measurement target, and a shunt resistance connected in series with the measurement target. The voltage across the above (signal indicating the current flowing through the measurement target (Vi: Ai × sin (ωt + Bi) + Ci)) is input as two measured signals (measured sine wave signal), and the impedance of the measurement target is measured. (calculate.

Specifically, this impedance measuring device synchronously detects the measured signal Vv with the reference signal sin (ωt) and obtains a signal component Vvs in phase with the reference signal sin (ωt) and the measured signal Vv as the reference signal cos. The signal component Vvc having the same phase as the reference signal cos (ωt) obtained by synchronous detection with (ωt) and the signal to be measured Vi having the same phase as the reference signal sin (ωt) obtained by synchronous detection with the reference signal sin (ωt). The signal component Vis, which is in phase with the reference signal cos (ωt) obtained by synchronously detecting the signal component Vis and the signal to be measured Vi with the reference signal cos (ωt), is the reference signal (sin (ωt), cos (ωt)). DC component T / 2 × Av × cos (Bv) for each obtained by integrating over a period that is a constant multiple of the period of (for example, the shortest period (period from zero to time T)). The impedance Z is calculated based on T / 2 × Av × sin (Bv), T / 2 × Ai × cos (Bi) and T / 2 × Ai × sin (Bi).

In this case, in this impedance measuring device, paying attention to the periodicity of the sine wave, as described above, each signal component Vvs, Vvc, Vis, Vic is integrated over one period T (= 2π / ω) at the shortest. As a result, the AC components (sin (ωt), cos (ωt), sin (2ωt), cos (2ωt)) contained in each signal component Vvs, Vvc, Vis, and Vic are removed, and each of the above DC components is removed. It is calculated.

Japanese Unexamined Patent Publication No. 2018-36089 (pages 4-8, 13-19)

However, the above-mentioned conventional impedance measuring device has the following problems to be solved. That is, in this impedance measuring device, integration is performed over a period of a constant multiple of the basic period (which is also the period of the reference signal (sin (ωt), cos (ωt)) of each signal to be measured Vv, Vi). However, since the period of this integration requires at least one cycle of this basic cycle, each signal to be measured Vv and Vi must be measured (acquired) over at least one cycle of the reference signal. Therefore, the impedance measuring device as the electric quantity measuring device always requires a time of one cycle or more of the measured signal (measured sinusoidal wave signal) until the measurement of the impedance Z as the electric quantity for the measurement target is completed. There is a problem of becoming.

The present invention has been made to solve such a problem, and the parameters (amplitude, initial phase and offset) of the sine wave signal to be measured are set based on the waveform data for 1/4 period of the sine wave signal to be measured. The main purpose is to provide a parameter calculation device and a parameter calculation method that can be calculated. Another main object of the present invention is to provide an electric quantity measuring apparatus provided with this parameter calculating apparatus for measuring an electric quantity (impedance, electric power value, etc.) of a measurement target that generates a sine wave signal to be measured.

In order to achieve the above object, the parameter calculation device according to claim 1 has acquired 1 / of the sine wave signal x (= Asin (2πft) + M) whose frequency f is known and whose amplitude A and offset M are unknown. Based on the waveform data Dw for 4 cycles, the initial phase θ (θ is a value within the angle range of 2π of −π / 4 or more and 7π / 4 or less) and the amplitude of the sine wave signal x to be measured at the time of acquisition. A parameter calculation device that calculates each parameter of A and the offset M, and is a reference sine wave signal y (= Bsin (2πft + φ) + N) of the initial phase φ having the frequency f and the amplitude B and the offset N known. The first reference sine wave signal y _φ1 (= Bsin (2πft + φ1)) in which the initial phase φ of is set to φ1 (φ1 is one of π / 4, 3π / 4, 5π / 4, and 7π / 4). ) + N) The first reference waveform data Drw ₁ for 1/4 cycle, and the second reference sine wave signal y with the initial phase φ of the reference sine wave signal y as φ2 (= φ1-π / 2). The second reference waveform data Drw ₂ for 1/4 cycle of _φ2 (= Bsin (2πft + φ2) + N) is provided with a storage unit and a processing unit in which the second reference waveform data Drw ₂ is stored in advance, and the processing unit is for the 1/4 cycle. Based on the waveform data Dw of the above and the first reference waveform data Drw ₁ for the 1/4 cycle, the sine wave signal x (= Asin (2πft + θ) + M) represented by the waveform data Dw and the first The first correlation coefficient calculation process for calculating the first correlation coefficient r _φ1 with the reference sine wave signal y _φ1 , the waveform data Dw for the 1/4 cycle, and the second reference waveform data for the 1/4 cycle. Second correlation coefficient calculation process for calculating the second correlation coefficient r _φ2 between the measured sine wave signal x (= Asin (2πft + θ) + M) and the second reference sine wave signal y _φ2 based on Drw _2. And the correlation coefficient r of the following equation (1) showing the correlation coefficient r between the sine wave signal x (= Asin (2πft + θ) + M) to be measured and the reference sine wave signal y (= Bsin (2πft + φ) + N). The process of calculating the first initial phase θ _φ1 with r as the first correlation coefficient r _φ1 and the initial phase φ of the equation (1) as the _φ1 and the correlation coefficient r of the equation (1). One of the processes of calculating the second initial phase θ _φ2 with the second correlation coefficient r _φ2 and the initial phase φ of the equation (1) as the φ2 is executed to obtain the first initial phase θ _φ1 and Any of the second initial phase θ _φ2 The tentative initial phase calculation process is calculated as the tentative initial phase θx, and the initial phase θ of the following equation (1) is set to φ1 and the initial phase θ of the equation (1) is set to −π / 4 to 7π / within the angle range. The polarity of the correlation coefficient r calculated when changed to 4 for each angle range of π / 2 and the initial phase φ of the following equation (1) are defined as φ2, and the initial phase θ of the equation (1) is defined as the above. Of the four combinations of the correlation coefficient r calculated when changing from −π / 4 to 7π / 4 within the angle range with the polarity of each angle range of π / 2 and the relevant π / 2 angle range. Among them, one combination that matches the combination of the respective polarities of the first correlation coefficient r _φ1 and the second correlation coefficient r _φ2 is specified, and among the conversion formulas associated with each of the four combinations in advance. The first parameter calculation process for calculating the initial phase θ by converting the temporary initial phase θx with the conversion formula associated with the specified one combination, and the calculated initial phase θ for the 1/4 cycle. From the first waveform data Dwst of the arbitrary two waveform data Dwa and Dwb having different values in the waveform data Dw and the waveform data Dw for the 1/4 cycle of the two waveform data Dwa and Dwb. The second parameter calculation process for calculating the amplitude A and the offset M from the simultaneous equations of the following equations (2) and (3) defined by the phase differences ψa and ψb of the above is executed.
r = (Dcos (θ-φ) -Csin (θ + φ)) / (√ (D-Csin2θ) √ (D-Csin2φ)) ... (1)
^{However, C = 4 / π 2 -1} / π, a ^{D = 1 / 2-4 / π 2} .
Dwa = Asin (ψa + θ) + M ・ ・ ・ (2)
Dwb = Asin (ψb + θ) + M ・ ・ ・ (3)

The parameter calculation device according to claim 2 is the parameter calculation device according to claim 1, wherein the processing unit has the waveform data Dwst and the last waveform data Dwen of the waveform data Dw for the quarter period. When the values are different, the waveform data Dwst and the waveform data Dwen are used as the two waveform data Dwa and Dwb in the second parameter calculation process, and the values are 0, π / 2 as the phase differences ψa and ψb. To use.

The parameter calculation method according to claim 3 is waveform data for 1/4 cycle acquired for a sine wave signal x (= Asin (2πft) + M) whose frequency f is known and whose amplitude A and offset M are unknown. Based on Dw, the initial phase θ (θ is a value within the angle range of 2π of −π / 4 or more and 7π / 4 or less), the amplitude A, and the offset M of the sine wave signal x to be measured at the time of acquisition. A parameter calculation method for calculating each parameter, in which the initial phase φ of the reference sine wave signal y (= Bsin (2πft + φ) + N) of the initial phase φ having the frequency f and the amplitude B and the offset N being known is obtained. 1 for the first reference sine wave signal y _φ1 (= Bsin (2πft + φ1) + N) as φ1 (φ1 is one of π / 4, 3π / 4, 5π / 4, and 7π / 4). The first reference waveform data Drw _{1 for} / 4 cycles and the second reference sine wave signal y _φ2 (= Bsin (2πft + φ2)) in which the initial phase φ of the reference sine wave signal y is φ2 (= φ1-π / 2). ) + N) The second reference waveform data Drw ₂ for 1/4 cycle is used, and based on the waveform data Dw for 1/4 cycle and the 1st reference waveform data Drw ₁ for 1/4 cycle. The first phase relationship for calculating the first correlation coefficient r _φ1 between the measured sine wave signal x (= Asin (2πft + θ) + M) represented by the waveform data Dw and the first reference sine wave signal y _φ1. Based on the number calculation process and the waveform data Dw for the 1/4 cycle and the second reference waveform data Drw ₂ for the 1/4 cycle, the sine wave signal x (= Asin (2πft + θ) + M) to be measured The second correlation coefficient calculation process for calculating the second correlation coefficient r _φ2 with the second reference sine wave signal y _φ2 , the measured sine wave signal x (= Asin (2πft + θ) + M), and the reference sine wave. The correlation coefficient r of the following equation (1) showing the correlation coefficient r with the signal y (= Bsin (2πft + φ) + N) is set to the first correlation coefficient r _φ1 , and the initial phase φ of the equation (1). The first initial phase θ _φ1 is calculated by setting _φ1 and the correlation coefficient r of the formula (1) is set to the second correlation coefficient r _φ2 , and the initial phase φ of the formula (1) is set to the above. Temporary initial phase calculation that executes any of the processes for calculating the second initial phase θ _φ2 as _φ2 and calculates either the first initial phase θ _φ1 or the second initial phase θ _φ2 as the temporary initial phase θx. Processing and the following formula (1) The angular range of π / 2 of the correlation coefficient r calculated when the initial phase θ of the equation (1) is changed from −π / 4 to 7π / 4 within the angular range with the initial phase φ as the φ1. It is calculated when each polarity and the initial phase θ of the following equation (1) are changed to φ2 and the initial phase θ of the equation (1) is changed from −π / 4 to 7π / 4 within the angular range. From the four combinations of the correlation coefficient r with the polarity for each π / 2 angle range and the π / 2 angle range for each of the four combinations, the first correlation coefficient r _φ1 and the second correlation coefficient r _φ2 are each. One combination that matches the combination of polarities is specified, and the tentative initial phase θx is converted by the conversion formula associated with the specified one combination among the conversion formulas previously associated with each of the four combinations. The first parameter calculation process for calculating the initial phase θ, and any two waveform data Dwa, Dwb having different values from the calculated initial phase θ and the waveform data Dw for the 1/4 cycle, and Simultaneous of the following equations (2) and (3) defined by the phase differences ψa and ψb from the first waveform data Dwst of the waveform data Dw for the 1/4 cycle of the two waveform data Dwa and Dwb. The second parameter calculation process for calculating the amplitude A and the offset M from the equation is executed.
r = (Dcos (θ-φ) -Csin (θ + φ)) / (√ (D-Csin2θ) √ (D-Csin2φ)) ... (1)
^{However, C = 4 / π 2 -1} / π, a ^{D = 1 / 2-4 / π 2} .
Dwa = Asin (ψa + θ) + M ・ ・ ・ (2)
Dwb = Asin (ψb + θ) + M ・ ・ ・ (3)

The parameter calculation method according to claim 4 is performed when the waveform data Dwst and the last waveform data Dwen of the waveform data Dw for the quarter period are different values in the parameter calculation method according to claim 3. In the second parameter calculation process, the waveform data Dwst and the waveform data Dwen are used as the two waveform data Dwa and Dwb, and the values 0 and π / 2 are used as the phase differences ψa and ψb.

The electric quantity measuring device according to claim 5 has a current detection unit that detects a sine wave current flowing through a target to be measured and outputs current waveform data for the sine wave current, and 1/4 of the current waveform data. A request for acquiring current waveform data for a period as the waveform data Dw and calculating each parameter of the initial phase θ, the amplitude A, and the offset M for the sine wave current as the sine wave signal x to be measured. A measuring unit that measures the current value of the sine wave current as the amount of electricity to be measured by using the parameter calculation device according to Item 1 or 2 and the calculated initial phase θ, the amplitude A, and the offset M. And have.

The electric quantity measuring device according to claim 6 has a voltage detecting unit that detects a sine wave voltage generated in a measurement target and outputs voltage waveform data about the sine wave voltage, and 1 / of the voltage waveform data. The voltage waveform data for four cycles is acquired as the waveform data Dw, and the parameters of the initial phase θ, the amplitude A, and the offset M for the sine wave voltage as the sine wave signal x to be measured are calculated. A measurement in which the voltage value of the sine wave voltage is measured as the amount of electricity to be measured by using the parameter calculation device according to claim 1 or 2 and the calculated initial phase θ, the amplitude A, and the offset M. It has a department.

The electric quantity measuring device according to claim 7 has a current detection unit that detects a sine wave current flowing through the object to be measured and outputs current waveform data about the sine wave current, and the sine wave current is applied to the object to be measured. The voltage detection unit that detects the sine wave voltage generated in the object to be measured when it is flowing and outputs the voltage waveform data for the sine wave voltage, the parameter calculation device according to claim 1 or 2, and the measurement unit. The parameter calculation device acquires current waveform data for 1/4 cycle of the current waveform data as the waveform data Dw, and obtains the sine wave current as the sine wave signal x to be measured. The parameters of the initial phase θ, the amplitude A, and the offset M are calculated, and the voltage waveform data for 1/4 cycle of the voltage waveform data is acquired as the waveform data Dw to be measured. Each parameter of the initial phase θ, the amplitude A and the offset M for the sinusoidal voltage as the sinusoidal signal x was calculated, and the measuring unit calculated the initial phase θ for the calculated sinusoidal current. The power supplied to the object to be measured based on the respective parameters of the amplitude A and the offset M, the initial phase θ for the calculated sinusoidal voltage, and the parameters of the amplitude A and the offset M. At least one of the value and the impedance of the object to be measured is measured as the amount of electricity of the object to be measured.

According to the parameter calculation device according to claim 1 and the parameter calculation method according to claim 3, the 1/4 cycle acquired for the measured sine wave signal x whose frequency f is known and whose amplitude A and offset M are unknown. It is possible to calculate each parameter of the initial phase θ, the amplitude A, and the offset M for the sine wave signal x to be measured at the time of acquisition based on the waveform data Dw of.

According to the parameter calculation device according to claim 2 and the parameter calculation method according to claim 4, since the values 0, π / 2 known as the phase differences ψa and ψb can be used, the phase differences ψa and ψb can be used. The time required for calculation can be saved.

According to the electric quantity measuring device according to claim 5, by providing the above-mentioned parameter calculating device, substantially 1/4 of the sinusoidal current as the measured sinusoidal signal measured with respect to the object to be measured. The current value of the sine wave current flowing through the object to be measured can be measured (calculated) as the amount of electricity of the object to be measured in a time substantially equal to the time required to acquire the waveform data Dw for the period.

According to the electric quantity measuring device according to claim 6, by providing the above-mentioned parameter calculating device, substantially 1/4 of the sinusoidal voltage as the measured sinusoidal signal measured with respect to the measured object. The voltage value of the sine wave voltage generated in the object to be measured can be measured (calculated) as the amount of electricity of the object to be measured in a time substantially equal to the time required to acquire the waveform data Dw for the period.

According to the electric quantity measuring device according to claim 7, by providing the above-mentioned parameter calculating device, substantially, the sinusoidal current and the sinusoidal voltage as the measured sinusoidal signal measured with respect to the object to be measured. The power value of the power supplied to the measurement target and the impedance of the measurement target are measured as the amount of electricity of the measurement target in a time that is almost the same as the time required to acquire each waveform data Dw for 1/4 cycle of. Can be (calculated).

It is a block diagram of the parameter calculation apparatus 1 and the electric quantity measuring apparatus 11 provided with this. It is a block diagram which shows the structure of the conversion table TBL used in the parameter calculation process 50. It is a graph which shows the relationship between the initial phase θ and each correlation coefficient r (r ₄₅ , r ₋₄₅ ). It is a graph which shows the relationship between the initial phase θ and each correlation coefficient r (r ₂₂₅ , r ₁₃₅ ). It is explanatory drawing which shows the polarity of each correlation coefficient r (r- ₄₅ , r ₄₅ , r ₁₃₅ , r ₂₂₅ ) in each angle range of an initial phase θ. It is a graph which shows the relationship between the initial phase θ and the correlation coefficient r ² . Explanation for explaining the state of change of each correlation coefficient r _φ1 (r ₄₅ ), r _φ2 (r ₋₄₅ ) and tentative initial phase θx (θ ₄₅ , θ ₋₄₅ ) when the initial phase θ is changed. It is a figure. It is explanatory drawing which shows the value of the coefficient α, β in each angle range of the initial phase θ. It is a flowchart for demonstrating the parameter calculation process 50 (parameter calculation method). It is a flowchart for demonstrating the operation of the electric quantity measuring apparatus 11 and the electric quantity measuring process 60.

Hereinafter, embodiments of the parameter calculation device, the parameter calculation method, and the electric quantity measuring device will be described with reference to the accompanying drawings.

First, the configuration of the parameter calculation device 1 as the parameter calculation device and the electricity amount measurement device 11 as the electricity amount measurement device will be described with reference to the drawings.

As shown in FIG. 1, the electricity measurement device 11 includes a parameter calculation device 1, a signal source 12, a current detection unit 13, a voltage detection unit 14, and a first A / D conversion unit 15 (hereinafter, also referred to as an A / D conversion unit 15). A second A / D conversion unit 16 (hereinafter, also referred to as an A / D conversion unit 16), a measurement unit 17, and an output unit 18 are provided to measure the amount of electricity of the DUT to be measured (also simply referred to as a measurement target). It is configured to be possible. In this example, the electric amount measuring device 11 has, as an example, the electric power of the DUT to be measured, the current value I1 of the sinusoidal current I flowing through the DUT to be measured, and the voltage of the sinusoidal voltage V generated between both ends of the DUT to be measured. The value V1, the power value W1 of the power W consumed by the measurement target DUT, and the impedance Z of the measurement target DUT are measured.

As an example, the parameter calculation device 1 is configured to include a processing unit 2 and a storage unit 3, and is acquired based on the amplitude data for 1/4 cycle acquired for the sine wave signal to be measured measured with respect to the DUT to be measured. It functions as a parameter calculation device that calculates each parameter of the initial phase, amplitude, and offset of the sinusoidal signal to be measured at the time.

The processing unit 2 is shown in FIG. 10 when, for example, it is configured by a computer and a measurement start instruction is input from the outside (for example, when the operation unit is provided in the electric quantity measuring device 11). The parameter calculation process 50 (see FIG. 9) of the electric quantity measurement process 60 is executed to calculate the initial phase, amplitude, and offset parameters of the sinusoidal signal to be measured and output to the measurement unit 17. Further, the processing unit 2 executes control processing (processing for outputting a supply start instruction and a supply stop instruction, which will be described later) for the signal source 12 (the signal source of the measurement sine wave signal Ss). Further, the processing unit 2 generates a sampling clock S2 having a constant frequency (known) sufficiently higher than the frequency f of the measurement sine wave signal Ss, and outputs (supplies) it to the A / D conversion units 15 and 16. Execute the clock generation process.

In the electric quantity measurement process 60, the processing unit 2 converts the above-mentioned sine wave current I measured with respect to the measurement target DUT into one sine wave signal x ₁ (sine wave signal represented by the following equation (1)). The above sine wave voltage V is treated as another sine wave signal x _{2 to} be measured (sine wave signal represented by the following equation (2)), and is 1 / of the sine wave signal x _{1 to} be measured. 4 waveform data Dw ₁ of cycle and acquires the waveform data Dw ₂ 1/4 cycles of the measured sinusoidal signal _{x 2.} The sinusoidal signals x ₁ and x _{2 to} be measured have the same frequency f and are known, and have amplitudes A ₁ and A ₂ (also referred to as amplitude A when not particularly distinguished) and offsets M ₁ and M ₂ (particularly distinction). When not, the offset M) and the initial phases θ ₁ and θ ₂ (initial phase at the time of acquisition of each waveform data Dw ₁ and Dw ₂ ; also referred to as initial phase θ when not particularly distinguished) are unknown sinusoidal signals. .. The initial phase θ is a value within an angle range of 2π of −π / 4 or more and 7π / 4 or less. Further, each waveform data Dw ₁ and obtained by sampling the measured sine wave signals x ₁ and x ₂ whose frequency f is known by the sampling clock S2 of the known frequency by the A / D converters 15 and 16 are obtained. The numbers of the waveform data Dw ₁ and Dw ₂ for 1/4 cycle of Dw ₂ (also referred to as waveform data Dw when not particularly distinguished) are the same and are known numbers.
x ₁ = A ₁ sin (2πft + θ ₁ ) + M ₁ ... (1)
x ₂ = A ₂ sin (2πft + θ ₂ ) + M ₂ ... (2)

Further, in the parameter calculation process 50, the processing unit 2 receives the acquired waveform data Dw ₁ and the first reference waveform data Drw ₁ (described later, the first reference sine wave having the initial phase φ1) stored in the storage unit 3. Waveform data of signal y _{φ1. φ1} is one of π / 4,3π / 4,5π / 4,7π / 4) and second reference waveform data Drw ₂ ( _{second of} initial phase φ2 described later). The first correlation coefficient r _φ1 and the second for the sinusoidal current I (measured sinusoidal signal x ₁ ) based on the waveform data of the reference sinusoidal signal y _{φ2 (φ2} = φ1-π / 2). calculating a correlation coefficient r _.phi.2, further the first using the correlation coefficient r _.phi.1 and the second correlation coefficient r _.phi.2, initial phase theta _1, the amplitude a ₁ and offset for the sinusoidal signal x ₁ to be measured Each parameter of M ₁ is calculated. Further, the processing unit 2 describes the sine wave voltage V (measured sine wave signal x ₂ ) based on the acquired waveform data Dw ₂ and the first reference waveform data Drw ₁ and the second reference waveform data Drw _2. first calculating a correlation coefficient r _.phi.1 and the second correlation coefficient r _.phi.2 of further first using the correlation coefficient r _.phi.1 and the second correlation coefficient r _.phi.2, the measured sinusoidal signal x ₂ Each parameter of the initial phase θ ₂ , the waveform A ₂ and the offset M ₂ is calculated.

In the storage unit 3, as the reference waveform data used by the processing unit 2 in the parameter calculation processing 50, the measured sinusoidal signals x ₁ and x _{2 have} the same frequency f as the above-mentioned frequency f, and the amplitude B and the offset N are stored. 1/4 of the known reference sine wave signal y (= Bsin (2πft + φ) + N) of the initial phase φ with respect to the first reference sine wave signal y _φ1 (= Bsin (2πft + φ1) + N) with this initial phase φ as φ1. 1/4 cycle of the first reference waveform data Drw ₁ for the cycle and the second reference sine wave signal y _φ2 (= Bsin (2πft + φ2) + N) where the initial phase φ of the reference sine wave signal y is _φ2 . The second reference waveform data Drw ₂ is stored in advance. The number of the first reference waveform data Drw ₁ and Drw _{2 is the same as} the number of the waveform data Dw ₁ and Dw _{2 for} the above-mentioned 1/4 cycle.

Further, the conversion table TBL (see FIG. 2) used in the parameter calculation process 50 is stored in advance in the storage unit 3. This conversion table TBL sets each coefficient α, β in the conversion formula (θ = α · θx + β) for converting the temporary initial phase θx calculated in the temporary initial phase calculation process of the parameter calculation process 50 into the true initial phase θ. It is for identification. In the conversion table TBL, the angle range of 2π of the initial phase θ (−π / 4 or more and 7π / 4 or less) is divided by the difference (π / 2) of the initial phases φ1 and φ2, and the first to fourth angles are described later. A combination of the respective polarities of the first correlation coefficient r _φ1 and the second correlation coefficient r _φ2 calculated as described later by the processing unit 2 for each of the four angle ranges up to the angle range (first correlation coefficient r). Each coefficient α, β (substantially the above conversion formula) is stored in association with the polarity of _φ1 and the second correlation coefficient r (polarity of _φ2 ). In FIG. 2, as an example, the initial phase φ1 is set to π / 4 (45 degrees) of π / 4,3π / 4,5π / 4,7π / 4, and the initial phase φ2 is set to this π / 4. It is related to each polarity of the first correlation coefficient r ₄₅ and the second correlation coefficient r _-45 when the corresponding −π / 4 (-45 degrees) is set, but the combination of the initial phases φ1 and φ2 is this. It is not limited to the combination (π / 4 (45 degrees) and -π / 4 (-45 degrees)), but 3π / 4 (135 degrees) and the corresponding π / 4 (45 degrees), 5π /. It is also possible to combine 4 (225 degrees) and the corresponding 3π / 4 (135 degrees), 7π / 4 (315 degrees) and the corresponding 5π / 4 (225 degrees).

The conversion table TBL will be described below.

The first correlation coefficient r _φ1 has the same frequency f as the first reference sinusoidal signal y _φ1 and the initial phases θ ₁ and θ ₂ as represented by the above equations (1) and (2). Initial phase θ such as θ, amplitude A such as amplitude A ₁ and A ₂ , and offset M such as offset M ₁ and M ₂ are unknown Sine wave signals to be measured x. A signal expressed by the equation Asin (2πft + θ) + M. ) And the first reference sine wave signal y _φ1 (= Bsin (2πft + φ1) + N), which is the correlation coefficient r. The second correlation coefficient r _φ2 is the correlation coefficient r between this sine wave signal (Asin (2πft + θ) + M) and the second reference sine wave signal y _φ2 (= Bsin (2πft + φ2) + N).

Correlation coefficient r between the reference sine wave signal y (= Bsin (2πft + φ) + N), which is the basis of each reference sine wave signal y _φ1 and y _φ2 , and the sine wave signal x (= Asin (2πft + θ) + M) to be measured, Specifically, the correlation coefficient r for the 1/4 wave (T / 4. T is one cycle (1 / f)) handled by the parameter calculation device 1 is calculated as follows. ..

A known formula for calculating the correlation coefficient r is
covariance of r = x and y / (standard deviation of x x standard deviation of y)
= (Average of product of x and y-Product of average of x and average of y) / (√ (Average of x ^2- (Average of x) ² ) x √ (Average of y ^2- (Average of y) ² )))
The correlation coefficient r is a real value of -1 or more and 1 or less. In addition, the processing unit 2 is based on this known calculation formula as an example, and in the first correlation coefficient calculation processing described later, the first reference waveform data Drw ₁ from the waveform data Dw ₁ and the first reference waveform data Drw ₁ regarding the sinusoidal current I. In addition to calculating the correlation coefficient r _φ1 , the second correlation coefficient r _φ2 for the sinusoidal current I is calculated from the waveform data Dw ₁ and the second reference waveform data Drw ₂ in the second correlation coefficient calculation process described later. To do. Further, the processing unit 2 has a first phase relationship with respect to the sinusoidal voltage V from the waveform data Dw ₂ and the first reference waveform data Drw ₁ in the first correlation coefficient calculation process described later based on this known calculation formula. In addition to calculating the number r _φ1 , the second correlation coefficient r _φ2 for the sinusoidal voltage V is calculated from the wave waveform data Dw ₂ and the second reference waveform data Drw ₂ in the second correlation coefficient calculation process described later. ..

Since the average of the products of x and y in this correlation coefficient r is 1/4 wave, it is expressed by the following equation when calculated for t = 0 to T / 4.
4 / T × ∫ [0, T / 4] (Asin (2πft + θ) + M) (Bsin (2πft + φ) + N) dt
= (AB / π) sin (θ + φ) + (AB / 2) cos (θ−φ)
+ (2AN / π) (sinθ + cosθ) + (2BM / π) (sinφ + cosφ) + MN
Note that ∫ [0, T / 4] g (t) dt indicates a definite integral from 0 to T / 4 in time t for the function g (t). The same applies to the following.

Further, the average of x is expressed by the following equation when calculated for t = 0 to T / 4.
4 / T × ∫ [0, T / 4] (Asin (2πft + θ) + M) dt
= (2A / π) (sinθ + cosθ) + M
Further, the average of y is expressed by the following equation when calculated for t = 0 to T / 4.
4 / T × ∫ [0, T / 4] (Bsin (2πft + φ) + N) dt
= (2B / π) (sinφ + cosφ) + N

Therefore, the product of the average of x and the average of y is expressed by the following equation.
((2A / π) (sinθ + cosθ) + M) ((2B / π) (sinφ + cosφ) + N)
= (4AB / π ² ) (sin (θ + φ) + cos (θ−φ)) + (2AN / π) (sinθ + cosθ)
+ (2BM / π) (sinφ + cosφ) + MN

Therefore, the covariance of x and y is expressed by the following equation (3) from the average of the products of x and y and the product of the average of x and the average of y.
(AB / π) sin (θ + φ) + (AB / 2) cos (θ−φ)
-(4AB / π ² ) (sin (θ + φ) + cos (θ−φ))
= AB ((1 / 2-4 / π 2) cos (θ-φ) - (4 / π 2 -1 / π) sin (θ + φ)) ··· (3)

Further, the average of x ² is expressed by the following equation when calculated for t = 0 to T / 4.
4 / T × ∫ [0, T / 4] (Asin (2πft + θ) + M) ² dt
^{= A 2/2 + (A} 2 / π) sin2θ + (4 AM/π) (sinθ + cosθ) + M 2

Further, since (average of x) ² is the square of the average of x described above, it is expressed by the following equation.
((2A / π) (sinθ + cosθ) + M) ²
= (4A ² / π ² ) (1 + sin2θ) + (4AM / π) (sinθ + cosθ) + M ²

Therefore, the standard deviation of x is expressed by the following equation (4) from the above-mentioned average of x ² and the above-mentioned (mean of x) ² .
^{√ (A 2/2 + (} A 2 / π) sin2θ- (4A 2 / π 2) (1 + sin2θ))
= A√ ((1 / 2-4 / π 2) - (4 / π 2 -1 / π) sin2θ) ··· (4)
Similarly, the standard deviation of y is expressed by the following equation (5).
B√ ((1 / 2-4 / π 2) - (4 / π 2 -1 / π) sin2φ) ··· (5)

As a result, the correlation coefficient r is expressed by the following equation (6) from the above equations (3), (4), and (5).
r = AB ((1 / 2-4 / π 2) cos (θ-φ) - (4 / π 2 -1 / π) sin (θ + φ)) / (A√ ((1 / 2-4 / π 2 ^{) - (4 / π 2 -1} / π) sin2θ) B√ ((1 / 2-4 / π 2) - (4 / π 2 -1 / π) sin2φ))
= (Dcos (θ-φ) -Csin (θ + φ)) / (√ (D-Csin2θ) √ (D-Csin2φ)) ... (6)
^{However, C = 4 / π 2 -1} / π, a ^{D = 1 / 2-4 / π 2} .

Since the equation (6) of the correlation coefficient r is an equation in which the initial phases θ and φ are variables, the first correlation coefficient r _φ1 with the initial phase _{φ as φ1} is only the initial phase θ as described above. Is a variable, and as described above, the second correlation coefficient r _φ2 with the initial phase φ as φ2 is also a function with only the initial phase θ as a variable.

Here, the above-mentioned −π / 4 (−45 degrees, which is also 7π / 4 (315 degrees)), π / 4 (45 degrees), and 3π / 4 (135 degrees) used as either of the initial phases φ1 and φ2. Degree), any one of 5π / 4 (225 degrees) is set as the initial phase φ in the equation (6) of the correlation coefficient r, over an angle range of 2π of −π / 4 or more and 7π / 4 or less. The correlation coefficient r when the initial phase θ is changed changes as shown in FIGS. 3 and 4.

Specifically, the correlation coefficient r (= r- ₄₅ ) when the initial phase φ is −π / 4 (−45 degrees) is from −π / 4 to π / as shown by the broken line in FIG. In the angle range up to 4, it gradually decreases from 1 to 0, and in the angle range from π / 4 to 3π / 4, it gradually decreases from 0 to -1, and the angle from 3π / 4 to 5π / 4 In the range, it gradually increases from -1 to 0, and in the angle range from 5π / 4 to 7π / 4, it gradually increases from 0 and returns to 1.

Further, the correlation coefficient r (= r ₄₅ ) when the initial phase φ is π / 4 (45 degrees) is in the angle range from −π / 4 to π / 4, as shown by the solid line in FIG. It gradually increases from 0 to 1, then gradually decreases from 1 to 0 in the angle range from π / 4 to 3π / 4, and gradually decreases from 0 in the angle range from 3π / 4 to 5π / 4. It reaches -1 and gradually increases from -1 and returns to 0 in the angle range from 5π / 4 to 7π / 4.

Further, the correlation coefficient r (= r ₁₃₅ ) when the initial phase φ is 3π / 4 (135 degrees) is in the angle range from −π / 4 to π / 4, as shown by the broken line in FIG. Gradually increase from -1 to 0, gradually increase from 0 to 1 in the angle range from π / 4 to 3π / 4, and gradually decrease from 1 in the angle range from 3π / 4 to 5π / 4. Then, it reaches 0, and in the angle range from 5π / 4 to 7π / 4, it gradually decreases from 0 and changes to return to -1.

Further, the correlation coefficient r (= r ₂₂₅ ) when the initial phase φ is 5π / 4 (225 degrees) is in the angle range from −π / 4 to π / 4, as shown by the solid line in FIG. It gradually decreases from 0 to -1, gradually increases from -1 to 0 in the angle range from π / 4 to 3π / 4, and gradually increases from 0 to 0 in the angle range from 3π / 4 to 5π / 4. It increases to 1 and gradually decreases from 1 to 0 in the angle range from 5π / 4 to 7π / 4.

Therefore, for each of the above correlation coefficients r (r- ₄₅ , r ₄₅ , r ₁₃₅ , r ₂₂₅ ), the respective polarities are constant at + or-from −π / 4 to π / 4 (−π / 4). Angle range of ≤θ <π / 4 (first angle range), angle range of π / 4 to 3π / 4 (π / 4 ≤θ <3π / 4) (second angle range), from 3π / 4 Angle range up to 5π / 4 (3π / 4 ≦ θ <5π / 4) (third angle range), and angle range from 5π / 4 to 7π / 4 (5π / 4 ≦ θ <7π / 4) Each polarity in the four angle range) is summarized in FIG. As is clear from FIG. 5, the combination of the initial phases φ1 and φ2 is the above four combinations (45 degrees and −45 degrees, 135 degrees and 45 degrees, 225 degrees and 135 degrees, and 315 degrees (−45 degrees). 225 degrees), the combination of the polarity of the first correlation coefficient r _{φ1 and} the polarity of the second correlation coefficient r _φ2 in all the angle ranges from the first angle range to the fourth angle range. Can all be in different states.

Further, the initial phase φ is φ1 (= π / 4.45 degrees), and the correlation coefficient r is the first correlation coefficient r _φ1 (the above-mentioned waveform data Dw _{1 and the} like and the first reference waveform data Drw of this initial phase φ1). _When θ is solved from the equation (6) calculated from ₁ above as the first correlation coefficient r _φ1 ), it becomes a function with the initial phase θ (first correlation coefficient r _φ1 as a variable). , Also referred to as the initial phase θ _φ1 for the sake of distinction) is as shown in the following equation (7).
θ _φ1 = 0.5 sin ^-1 ((CD + 2Dr _φ1 ² ) / (DC + 2Cr _φ1 ² )) ・ ・ ・ (7)
Further, the initial phase φ is φ2 (= −π / 4. −45 degrees) corresponding to this φ1, and the correlation coefficient r is the second correlation coefficient r _φ2 (the above-mentioned waveform data Dw _{1 and the} like and this initial phase φ2). When θ is solved from the equation (6), which is the above-mentioned second correlation coefficient r _φ2 calculated from the second reference waveform data Drw ₂ of the above, the initial phase θ (the second correlation coefficient r _φ2 is a variable). Therefore, in the following, for the sake of distinction, the initial phase θ _φ2 ) is as shown in the following equation (8).
θ _φ2 = 0.5 sin ^-1 ((C + D-2Dr _φ2 ² ) / (D + C-2Cr _φ2 ² )) ・ ・ ・ (8)

Further, the initial phase φ is φ1 (= 3π / 4.135 degrees), and the correlation coefficient r is the first correlation coefficient r _φ1 (the above-mentioned waveform data Dw _{1 and the} like and the first reference waveform data Drw of this initial phase φ1). _When θ is solved from the equation (6) calculated from ₁ and the above first correlation coefficient r _φ1 ), the initial phase θ _φ1 becomes the following equation (9).
θ _φ1 = 0.5 sin ^-1 ((C + D-2Dr _φ1 ² ) / (D + C-2Cr _φ1 ² )) ・ ・ ・ (9)
Further, the initial phase φ is φ2 (= π / 4) corresponding to this φ1, and the correlation coefficient r is the second correlation coefficient r _φ2 (the above-mentioned waveform data Dw _{1 and the} like and the second reference waveform of this initial phase φ2). When θ is solved from the equation (6), which is the second correlation coefficient r _φ2 ) calculated from the data Drw ₂ , the initial phase θ _φ2 becomes the following equation (10).
θ _φ2 = 0.5 sin ^-1 ((CD + 2Dr _φ2 ² ) / (DC + 2Cr _φ2 ² )) ・ ・ ・ (10)

Further, the initial phase φ is φ1 (= 5π / 4.225 degrees), and the correlation coefficient r is the first correlation coefficient r _φ1 (the above-mentioned waveform data Dw _{1 and the} like and the first reference waveform data Drw of this initial phase φ1). _When θ is solved from the equation (6) with the first correlation coefficient r _φ1 ) calculated from ₁ and ₁ , it becomes the above equation (7).
Further, the initial phase φ is φ2 (= 3π / 4) corresponding to this φ1, and the correlation coefficient r is the second correlation coefficient r _φ2 (the above-mentioned waveform data Dw _{1 and the} like and the second reference waveform of this initial phase φ2). When θ is solved from the equation (6), which is the second correlation coefficient r _φ2 ) calculated from the data Drw ₂ , it becomes the above equation (8).

Further, the initial phase φ is φ1 (= 7π / 4.315 degrees), and the correlation coefficient r is the first correlation coefficient r _φ1 (the above-mentioned waveform data Dw _{1 and the} like and the first reference waveform data Drw of this initial phase φ1). _When θ is solved from the equation (6) with the first correlation coefficient r _φ1 ) calculated from ₁ and ₁ , it becomes the above equation (9).
Further, the initial phase φ is φ2 (= 5π / 4) corresponding to this φ1, and the correlation coefficient r is the second correlation coefficient r _φ2 (the above-mentioned waveform data Dw _{1 and the} like and the second reference waveform of this initial phase φ2). When θ is solved from the equation (6), which is the second correlation coefficient r _φ2 ) calculated from the data Drw ₂ , it becomes the above equation (10).

Therefore, the combination of the above initial phases φ1 and φ2 is selected from the above four combinations (45 degrees and -45 degrees, 135 degrees and 45 degrees, 225 degrees and 135 degrees, 315 degrees (-45 degrees) and 225 degrees). When the combination of any one of the above is determined, one of the first correlation coefficient r _φ1 and the second correlation coefficient r _φ2 when the initial phases φ1 and φ2 included in the determined combination are determined. When the correlation coefficient r is known, one of the two equations (becomes known) corresponding to the initial phases φ1 and φ2 of the above equations (7), (8), (9), and (10). It is possible to calculate the initial phase θ based on the equation) with the correlation coefficient r as a variable.

However, in the above equations (7), (8), (9), and (10), the square values of the first correlation coefficient r _φ1 and the second correlation coefficient r _φ2 (that is, in the range of 0 or more and 1 or less). The value that changes) is a variable. As a result, as shown in FIG. 6, in the above equations (7), (8), (9), and (10) in which the square value r ² of the known correlation coefficient r is used as a variable, the square value is obtained. Initial phase θ corresponding to r ² (Since the possible value of the arc sign is in the range of −π / 2 or more and π / 2 or less, the possible value of this θ is half that, −π / 4 (-45 degrees). There is one more than π / 4 (45 degrees) or less) in the first angle range, the second angle range, the third angle range, and the fourth angle range.

Therefore, based on the known correlation coefficient r, one equation (for example, initial phase φ) corresponding to this correlation coefficient r among the above equations (7), (8), (9), and (10) is used. When the correlation coefficient r when π / 4 (45 degrees) is known, the above equation (7) (or equation (10)) corresponding to π / 4 (45 degrees), the initial phase φ is 3π / 4 When the correlation coefficient r when (135 degrees) is known, the initial phase θ is uniquely calculated from the above equation (8) (or equation (9)) corresponding to 3π / 4 (135 degrees). In order to do so, the initial phase θ calculated from this one equation (hereinafter, also referred to as a tentative initial phase θx for distinction) is any of the above four angle ranges (first angle range to fourth angle range). The tentative initial phase θx calculated as a value of −π / 4 (-45 degrees) or more and π / 4 (45 degrees) or less is converted into an angle in this specified angle range. There is a need.

First, a method of specifying the angle range including the tentative initial phase θx will be described. In this example, the combination of initial phases φ1 and φ2 is selected from the above four combinations (45 degrees and -45 degrees, 135 degrees and 45 degrees, 225 degrees and 135 degrees, 315 degrees (-45 degrees) and 225 degrees). In any combination, as shown in FIG. 5, the polarity and the second of the first correlation coefficient r _φ1 in all the angle ranges from the first angle range to the fourth angle range are used. A state in which all the polar combinations of the correlation coefficient r _φ2 are different (that is, the combination of the polarities of the first correlation coefficient r _φ1 and the second correlation coefficient r _φ2 is each angle range from the first angle range to the fourth angle range. There is a one-to-one correspondence with). Therefore, using the combination of the polarity of the first correlation coefficient r _{φ1 and} the polarity of the second correlation coefficient r _φ2 , the calculated tentative initial phase θx is in the first angle range as described with reference to FIG. To specify which of the fourth angle ranges is included in.

Next, a conversion formula (θ = α · θx + β) for converting the tentative initial phase θx into the actual initial phase θ will be described. As an example, an example in which the combination of the initial phases φ1 and φ2 is set to 45 degrees and −45 degrees will be described. The first reference waveform data Drw ₁ for 1/4 cycle of the first reference sine wave signal y _φ1 of the initial phase φ1 and the 1/4 cycle of the second reference sine wave signal y _φ2 of the initial phase φ2. The second reference waveform data Drw ₂ of the above is prepared, and the initial phase θ of the sine wave signal x to be measured is set to −45 degrees, -30 degrees, -15 degrees, 0 degrees, 15 degrees, 30 degrees, 45 degrees, Waveform data Dw and each reference waveform for 1/4 cycle of the sine wave signal x to be measured obtained when the phase is changed stepwise such as 60 degrees, 75 degrees, 90 degrees, 105 degrees, 120 degrees, and 135 degrees. The first correlation coefficient r _φ1 (r ₄₅ ) and the second correlation coefficient r _φ2 (r ₋₄₅ ) with the data Drw ₁ and Drw ₂ are calculated, and the calculated first correlation coefficient r _φ1 (r ₄₅ ) is further calculated. ) And the second correlation coefficient r _φ2 (r ₋₄₅ ) are substituted into the corresponding equations (7) and (8) to calculate the tentative initial phase θx. The result of executing the simulation is shown in FIG. In FIG. 7, for easy understanding, the tentative initial phase θx calculated from the first correlation coefficient r _φ1 (r ₄₅ ) is referred to as the tentative initial phase θ _45, and the second correlation coefficient r _φ2 (r). _The tentative initial phase θx calculated from ₋₄₅ ) is expressed as the tentative initial phase θ ₋₄₅ .

As is clear from the results of the simulation shown in FIG. 7, the initial phases θ of the two tentative initial phases θ ₄₅ and θ ₋₄₅ are −45 degrees, -30 degrees, -15 degrees, 0 degrees, and 15 degrees. -45 degrees, -30 degrees, -15 degrees, 0 degrees corresponding to gradual changes such as 30 degrees, 45 degrees, 60 degrees, 75 degrees, 90 degrees, 105 degrees, 120 degrees, 135 degrees. It changes in degrees, 15 degrees, 30 degrees, 45 degrees, 30 degrees, 15 degrees, 0 degrees, -15 degrees, -30 degrees, -45 degrees, and so on. Even when the initial phase θ is changed stepwise from 135 degrees to 7π / 5 (315 degrees), the first correlation coefficient r _φ1 (r ₄₅ ) and the second correlation coefficient are as shown in FIG. Since each square value r2 of r _φ2 (r ₋₄₅ ) changes in the same way as when the initial phase θ is changed stepwise from −45 degrees to 135 degrees, the two tentative initial phases θ ₄₅ and θ _{− 45} also changes in the same manner as when the initial phase θ is changed stepwise from −45 degrees to 135 degrees.

Further, even when the combination of the initial phases φ1 and φ2 is made into three combinations other than 45 degrees and −45 degrees, the tentative initial phase θx changes in the same manner as in the case of the combination of 45 degrees and −45 degrees. Has been confirmed by simulation.

From this result, in all the above combinations of the initial phases φ1 and φ2, in the first angle range (from −π / 4 to π / 4), the tentative initial phase θx becomes the initial phase θ as it is, so that the coefficient α is It is 1 and the coefficient β is 0. Further, in the second angle range (from π / 4 to 3π / 4), the initial phase θ is obtained by adding 90 degrees to the value obtained by inverting the polarity of the tentative initial phase θx, so that the coefficient α is -1. , The coefficient β is 90 degrees (π / 2). Further, as described above, the tentative initial phase θx changes in the third angle range (from 3π / 4 to 5π / 4) in the same manner as in the first angle range, and changes from the fourth angle range (from 5π / 4). (Up to 7π / 4), it changes in the same way as in the second angle range.

Therefore, the coefficient α is set to the same value 1 in the third angle range as in the first angle range, and is set to the same value -1 in the fourth angle range as in the second angle range. On the other hand, the actual initial phase θ is 180 degrees (π) more in the third angle range than in the first angle range, and 180 degrees (π) in the fourth angle range than in the second angle range. Since the coefficient β increases, the value of the coefficient β is set to 180 degrees (π), which is 180 degrees (π) more than in the first angle range in the third angle range, and is set to 180 degrees (π) in the fourth angle range as well as in the second angle range. Is also set to a value of 225 degrees (3π / 2), which is 180 degrees (π) more. As a result, the coefficients α and β in each angle range from the first angle range to the fourth angle range are common regardless of the combination of the initial phases φ1 and φ2, and are defined as shown in FIG. ..

As an example in the present embodiment, the initial phase .phi.1, by employing the combination as a combination [pi / 4 of .phi.2 (45 °) and - [pi] / 4 (-45 °), the correlation coefficient shown in FIG. 5 _r 45, r _The conversion table TBL shown in FIG. 2 is composed of the polarity in each angle range for ₋₄₅ and the values in each angle range for the coefficients α and β shown in FIG. Although not shown, by adopting the combination of 3π / 4 (135 degrees) and π / 4 (45 degrees) as the combination of the initial phases φ1 and φ2, the correlation coefficients r ₁₃₅ and r ₄₅ shown in FIG. 5 are used. The conversion table TBL may be configured by the polarity in each angle range of and the value in each angle range of the coefficients α and β shown in FIG. The initial phase .phi.1, by employing the combination of 5 [pi] / 4 as a combination of .phi.2 (225 degrees) and 3 [pi] / 4 (135 °), the angle range of the correlation coefficient _{r 225, r 135} shown in FIG. 5 The conversion table TBL may be configured by the polarity in the above and the values in each angle range for the coefficients α and β shown in FIG. Further, by adopting the combination of 7π / 4 (315 degrees) and 5π / 4 (225 degrees) as the combination of the initial phases φ1 and φ2, the correlation coefficients _r225 and r- ₄₅ ( _r315 ) shown in FIG. The conversion table TBL may be configured by the polarity in each angle range of and the value in each angle range of the coefficients α and β shown in FIG.

As shown in FIG. 1, the signal source 12 is connected to one end TEa (one electrode) of the DUT to be measured, for example, via a probe 21. Further, the signal source 12 generates a sine wave current signal (a signal having a frequency f (constant) and a constant amplitude) based on the internal reference potential (potential of the ground G) of the electric quantity measuring device 11, and also has a sine wave for measurement. A current source output as a wave signal Ss, and a sine wave voltage signal (a signal having a constant frequency f (constant) and a constant amplitude) based on an internal reference potential (ground G potential) are generated, and a sine wave signal Ss for measurement is generated. It is composed of any of the voltage sources that output as. Further, the signal source 12 starts generating and outputting the measurement sine wave signal Ss when the supply start instruction is received from the processing unit 2, and then for measurement until the supply stop instruction is received from the processing unit 2. The generation and output of the sine wave signal Ss is continued. Further, the signal source 12 outputs the trigger signal S1 to the processing unit 2 in synchronization with the start timing of the output of the measurement sine wave signal Ss. In this example, as an example, the signal source 12 starts the output of the measurement sine wave signal Ss as a signal starting from the zero crossing point (a signal having an initial phase of zero), and synchronizes the trigger signal S1 with the zero crossing point. Output, but is not limited to this. For example, the signal source 12 starts outputting the measurement sine wave signal Ss as a signal starting from a point other than the zero crossing point (a signal whose initial phase is not zero), and outputs the trigger signal S1 in synchronization with the start of the signal. It is also possible to adopt a configuration that does.

The current detection unit 13 is composed of a shunt resistor (fixed resistor having a small resistance value for current detection) as an example, and one of a pair of detection terminals (not shown) measures, for example, via a probe 22. It is connected to the other end TEb (the other electrode) of the target DUT, and the other detection terminal is connected to the internal reference potential (ground G). Further, the current detection unit 13 detects the sine wave current I (measured sine wave signal x ₁ ) flowing through the measurement target DUT by outputting the measurement sine wave signal Ss from the signal source 12 to the measurement target DUT. , A current detection signal Vi (that is, a signal indicating the sine wave current I) whose voltage value changes in proportion to the current value of the sine wave current I is output. The current detection unit 13 is not limited to the shunt resistor, and may be composed of a non-contact type current probe.

In the voltage detection unit 14, one of the pair of detection terminals (not shown) is connected to one end TEa of the measurement target DUT via, for example, the probe 23, and the other detection terminal is connected to, for example, the probe 24. It is connected to the other end TEb (the other electrode) of the DUT to be measured. Further, the voltage detection unit 14 has a sine wave voltage V (measured sine wave signal x) as a voltage between both ends generated in the measurement target DUT in a state where the sine wave current I is flowing (supplied) to the measurement target DUT. ₂ ) is detected, and a voltage detection signal Vv (that is, a signal indicating the voltage V between both ends) whose voltage value changes in proportion to the voltage value of the sinusoidal voltage V is output.

The A / D conversion unit 15 is configured to include, for example, an amplifier and an A / D converter (neither is shown), and the input current detection signal Vi is supplied from the processing unit 2 to the sampling clock S2. The waveform data Di (data showing the instantaneous value of the current detection signal Vi, equivalently the current waveform data showing the instantaneous value of the sinusoidal current I) for the current detection signal Vi is output by sampling in synchronization with. In this case, in the A / D converter 15, the amplifier is configured by using, for example, an operational amplifier having a high input impedance, and the input current detection signal Vi is a voltage that matches the input specifications of the A / D converter. It is amplified to a level and output to an A / D converter, and the A / D converter samples the amplified current detection signal Vi in synchronization with the sampling clock S2 and converts it into waveform data Di.

The A / D conversion unit 16 is configured in the same manner as the A / D conversion unit 15 and samples the input voltage detection signal Vv in synchronization with the sampling clock S2 to obtain waveform data about the voltage detection signal Vv. Dv (data indicating the instantaneous value of the voltage detection signal Vv, equivalently voltage waveform data indicating the instantaneous value of the sinusoidal voltage V) is output in a state synchronized with the waveform data Di.

The measuring unit 17 is configured by, for example, a computer, executes the electricity amount calculation process following the parameter calculation process 50 of the electricity amount measurement process 60 shown in FIG. 10, and executes the electricity amount calculation process, and the sinusoidal current I flowing through the measurement target DUT. Current value I1, voltage value V1 of sinusoidal voltage V generated between both ends of the measurement target DUT, power value W1 of the power W consumed by the measurement target DUT, and the impedance Z of the measurement target DUT are the electricity of the measurement target DUT. Measure as a quantity. Further, the measuring unit 17 executes an output process following the electric energy calculation process, and causes the output unit 18 to output the measured electric energy of the current value I1, the voltage value V1, the power value W1, and the impedance Z.

As an example, the output unit 18 is configured by a display device, and displays (outputs) each amount of electricity (current value I1, voltage value V1, power value W1 and impedance Z) output from the processing unit 2 on the screen. ). The output unit 18 can be configured by various interface circuits instead of the display device, and when it is configured by the external interface circuit, each electric amount is connected to the external device connected by the transmission line via the external interface circuit. Is output, and when it is composed of a medium interface circuit, each amount of electricity is stored in a storage medium connected to the medium interface circuit.

The electric energy measuring device 11 of this example adopts a configuration in which the processing unit 2 and the measuring unit 17 of the parameter calculation device 1 are separate bodies, but the processing unit 2 and the measuring unit 17 are integrated. A configuration (that is, a configuration in which the processing unit 2 executes all the processes of the electric energy measurement process 60 including the electric energy calculation process and the output process) may be adopted. Further, the parameter calculation device 1 may be configured to include the A / D conversion units 15 and 16 respectively.

Next, the operation of the electricity quantity measuring device 11 will be described together with the operation of the parameter calculation device 1 and the parameter calculation method. It is assumed that the electric quantity measuring device 11 is connected to the measurement target DUT via the probes 21, 22, 23, 24, respectively. Further, it is assumed that the processing unit 2 generates the sampling clock S2 and outputs (supplies) it to the A / D conversion units 15 and 16.

In the electric quantity measuring device 11, the processing unit 2 detects the presence / absence of an input of a measurement start instruction from the outside, and when the input of the measurement start instruction is detected, the electric quantity measuring process 60 shown in FIG. 10 is executed. .. In the electricity quantity measurement process 60, the processing unit 2 first transmits a supply start instruction to the signal source 12 to cause the signal source 12 to start the generation and output of the measurement sine wave signal Ss (step 61). .. As a result, the measurement sine wave signal Ss is output from the signal source 12 to the measurement target DUT, so that the signal source 12 reaches the ground G via the probe 21, the measurement target DUT, the probe 22, and the current detection unit 13. A sinusoidal current I flows along the path leading to it. Further, the signal source 12 outputs the trigger signal S1 to the processing unit 2 in synchronization with the start timing of the output of the measurement sine wave signal Ss.

Current detector 13, the sinusoidal current I is detected as a sine wave signal x ₁ to be measured, and outputs a current detection signal Vi to A / D converter 15. The A / D conversion unit 15 converts the current detection signal Vi into waveform data Di by sampling in synchronization with the sampling clock S2, and outputs the current detection signal Vi to the processing unit 2.

The voltage detecting unit 14, a sinusoidal voltage V generated in the measurement target DUT by flowing a sinusoidal current I is detected as a sine wave signal x ₂ to be measured, the voltage detection signal Vv the A / D converter 16 Output to. The A / D conversion unit 16 converts the voltage detection signal Vv into waveform data Dv by sampling in synchronization with the sampling clock S2, and outputs the voltage detection signal Vv to the processing unit 2.

The processing unit 2 executes the waveform data acquisition process when the trigger signal S1 output from the signal source 12 is input (step 62). In this waveform data acquisition process, the processing unit 2 starts acquiring waveform data Di and waveform data Dv in synchronization with the input timing of the trigger signal S1, and has one cycle T of the measurement sinusoidal signal Ss (known: The waveform data Di and the waveform data Dv were acquired over a period (T / 4) of 1/4 of 1 / f), and the acquired waveform data Di was ₁ for the measured sinusoidal signal x1. The waveform data Dv ₁ stored as waveform data Dw ₁ (wave data represented by the above equation (1)) for / 4 cycles is for 1/4 cycle of the measured sinusoidal signal x ₂ . It is stored as waveform data Dw ₂ (wave data represented by the above equation (2)).

Further, after completing the acquisition of the waveform data Dv and the waveform data Di (that is, the acquisition and storage of the waveform data Dw ₁ and Dw ₂ ), the processing unit 2 transmits a supply stop instruction to the signal source 12 to signal. The generation and output of the measurement sine wave signal Ss is stopped for the source 12 (step 63).

Next, the processing unit 2 executes the first parameter calculation process 50 in the electricity quantity measurement process 60 (step 64). In the parameter calculation process 50, the processing unit 2, based on the waveform data Dw ₁ obtained, the initial phase theta ₁ of the measured sinusoidal signal _{x 1} (sinusoidal current I), the amplitude _{A 1} and offset _{M 1} Calculate each parameter.

The processing unit 2 first executes the first correlation coefficient calculation process (step 51). In this first correlation coefficient calculation process, the processing unit 2 uses the waveform data Dw ₁ and the first reference waveform data Drw ₁ to obtain a sine wave current I based on the above-mentioned known calculation formula for the correlation coefficient r. 1 Calculate the correlation coefficient r ₄₅ . Next, the processing unit 2 executes the second correlation coefficient calculation process (step 52). In this second correlation coefficient calculation process, the processing unit 2 uses the known calculation formula of the correlation coefficient r to obtain a _second reference wave current I from the waveform data Dw ₁ and the second reference waveform data Drw 2. The correlation coefficient r- ₄₅ is calculated.

Next, the processing unit 2 executes the tentative initial phase calculation process (step 53). In this temporary initial phase calculation process, the processing unit 2 calculates the initial phase θ ₄₅ as the temporary initial phase θx by using the first correlation coefficient r ₄₅ calculated based on the above equation (7).

Subsequently, the processing unit 2 executes the first parameter calculation process (step 54). In this first parameter calculation process, the processing unit 2 calculates the initial phase θ ₁ , which is one of the unknown parameters for the measured sinusoidal signal x ₁ (sinusoidal current I).

Specifically, the processing unit 2 refers to the conversion table TBL of FIG. 2 stored in the storage unit 3, and first, first, the first of each of the four angle ranges from the first angle range to the fourth angle range. from among the polarity combinations of the correlation coefficient _{r 45} and the second correlation coefficient _{r -45} (4 one combination for each polarity), the first correlation coefficient _{r 45} and the second correlation coefficient _{r -45} calculated Identify one combination that matches each polarity combination of. For example, when the combination of the calculated polarities of the first correlation coefficient r ₄₅ and the second correlation coefficient r ₋₄₅ is (+, −), the processing unit 2 refers to the conversion table TBL and second. It is specified that the polar combinations (+,-) stored in association with the angle range are one matching combination. Next, the processing unit 2 uses the coefficients α and β (that is, the conversion formula: α · θx + β) associated with the specified one polarity combination (that is, the specified one angle range) in advance, and the tentative initial phase. The initial phase θ ₁ is calculated by converting θx to the true initial phase θ.

Next, the processing unit 2 executes the second parameter calculation process (step 55). In this second parameter calculation process, the processing unit 2 sets each parameter of the amplitude A ₁ and the offset M ₁ which are the remaining parameters of the unknown parameters for the measured sine wave signal x ₁ (sine wave current I). calculate.

Specifically, the processing unit 2 has the calculated initial phase θ ₁ , the acquired waveform data Dw ₁ for 1/4 cycle, any two waveform data Dwa, Dwb having different values, and the two waveforms. data Dwa, each phase difference from the first waveform data Dwst (first waveform data of the waveform data Dw ₁ 1/4 period acquired) for Dwb .phi.a, formula as defined in ψb (11), ( The waveform A ₁ and the offset M ₁ are calculated from the simultaneous equations in 12). For each phase difference ψa, ψb, the processing unit 2 determines the number of each data from the waveform data Dwst to each waveform data Dwa, Dwb, the period of the sampling clock S2, and the sine wave signals x ₁ , x _{2 to} be measured. The processing unit 2 calculates based on the known 1-cycle T (= 1 / f).
Dwa = A ₁ sin (ψa + θ ₁ ) + M ₁ ... (11)
Dwb = A ₁ sin (ψb + θ ₁ ) + M ₁ ... (12)

As described above, the calculation of each parameter of the initial phase θ ₁ , the amplitude A ₁ and the offset M _{1 for} the measured sinusoidal signal x ₁ (sinusoidal current I) is completed. Further, the processing unit 2 outputs the calculated parameters of the initial phase θ ₁ , the amplitude A ₁ and the offset M ₁ to the measuring unit 17. As a result, the first parameter calculation process 50 in the electricity quantity measurement process 60 (parameter calculation process 50 for the measured sine wave signal x ₁ (sine wave current I)) is completed.

Next, the processing unit 2 executes the final parameter calculation process 50 in the electricity quantity measurement process 60 (step 65). In the parameter calculation process 50, the processing unit 2, based on the waveform data Dw ₂ obtained, the initial phase theta ₂ of the measured sinusoidal signal _{x 2} (sinusoidal voltage V), the amplitude _{A 2} and offset _{M 2} Calculate each parameter. The process of calculating each parameter of the initial phase θ ₂ , the amplitude A ₂ and the offset M ₂ based on the waveform data Dw ₂ is the initial phase θ for the sine wave signal x ₁ (sine wave current I) to be measured. _1, the amplitude a ₁ and waveform data Dw ₁ waveform data Dw ₂ in the process described above to calculate the parameters of the offset M _1, a sinusoidal signal x ₁ to be measured sinusoidal signal x ₂ to be measured, sinusoidal current Since I is the same as the sinusoidal voltage V, the initial phase θ ₁ is read as the initial phase θ ₂ , the amplitude A ₁ is read as the amplitude A ₂ , and the offset M ₁ is read as the offset M ₂ , the description is omitted. To do.

The processing unit 2 outputs the calculated parameters of the initial phase θ ₂ , the amplitude A ₂ and the offset M ₂ to the measuring unit 17. As a result, the final parameter calculation process 50 (parameter calculation process 50 for the measured sine wave signal x ₂ (sine wave voltage V)) in the electricity quantity measurement process 60 is completed.

Subsequently, the measuring unit 17 executes the electricity amount calculation process (step 66). In this electricity amount calculation process, the measuring unit 17 uses the sine wave as the sine wave signal x _{1 to} be measured based on the above equation (1) in which the parameters of the initial phase θ ₁ , the amplitude A ₁ and the offset M ₁ are known. The current value I1 of the wave current I is calculated. Further, the measuring unit 17 determines the voltage of the sine wave voltage V as the sine wave signal x _{2 to} be measured based on the above equation (2) in which the parameters of the initial phase θ ₂ , the amplitude A ₂ and the offset M ₂ are known. Calculate the value V1. Further, the measuring unit 17 measures the power value W1 of the power W consumed by the measurement target DUT and the impedance Z of the measurement target DUT based on the equations (1) and (2).

Finally, the measuring unit 17 executes an output process to output the measured (calculated) current value I1, voltage value V1, power value W1 and impedance Z to the output unit 18 (in this example, the display device). Display on the screen. Step 67). As a result, the electricity quantity measurement process 60 is completed.

In this case, the processing unit 2 of the parameter calculation device 1 is configured by a computer, and from the acquired waveform data Dw ₁ and Dw ₂ , each of the above parameters (initial phase θ ₁ , θ ₂ , amplitude A ₁ , A ₂ , and It calculates the offset _M 1, _{M 2)} a very short time, and outputs the measurement section 17. Further, the measuring unit 17 of the electric quantity measuring device 11 is also configured by a computer, and each of the acquired parameters (initial phase θ ₁ , θ ₂ , amplitude A ₁ , A ₂ , and offset M ₁ , M ₂ ) is obtained. The amount of electricity (current value I1, voltage value V1, power value W1 and impedance Z) is calculated in an extremely short time and displayed on the output unit 18. Therefore, the electric quantity measuring device 11 substantially takes time to acquire the waveform data Dw ₁ and Dw ₂ for 1/4 cycle of the sinusoidal current I and the sinusoidal voltage V measured with respect to the DUT to be measured. It is possible to calculate each amount of electricity (current value I1, voltage value V1, power value W1 and impedance Z) and display it on the output unit 18 (measure each amount of electricity) in about the same time as. ing.

As described above, according to the parameter calculation device 1 and the parameter calculation method, the measured sine wave signals x ₁ , x ₂ whose frequency f is known and whose amplitudes A ₁ , A ₂ and offsets M ₁ , M ₂ are unknown. Initial phase θ ₁ , θ ₂ , amplitude A ₁ , A ₂ and offset for the measured sinusoidal signals x ₁ and x ₂ at the time of acquisition based on the waveform data Dw ₁ and Dw ₂ for 1/4 cycle acquired. Each parameter of M ₁ and M ₂ can be calculated. As a result, according to the electricity quantity measuring device 11 provided with the parameter calculating device 1, the sinusoidal current I and the sinusoidal voltage V as the measured sinusoidal signals measured with respect to the DUT to be measured are substantially 1. The amount of electricity (current value I1, voltage value V1, power value W1 and impedance Z) for the DUT to be measured is approximately the same as the time required to acquire the waveform data Dw ₁ and Dw ₂ for / 4 cycles. It can be measured (calculated).

Further, in the above example, the processing unit 2 performs arbitrary two waveform data having different values in the acquired waveform data Dw ₁ (or waveform data Dw ₂ ) for 1/4 cycle in the second parameter calculation process. Although the configuration using Dwa and Dwb is adopted, the waveform data Dwst, which is the first waveform data of the acquired waveform data Dw ₁ (or waveform data Dw ₂ ) for 1/4 cycle, and 1/4. When the last waveform data Dwen of the cycle data Dw ₁ (or waveform data Dw ₂ ) has a different value, the waveform data Dwst and the waveform data Dwen are used as the two waveform data Dwa and Dwb. Can also be adopted. According to this configuration, the values 0, π / 2, which are known as the phase differences ψa and ψb described above, can be used, so that the time required for calculating the phase differences ψa and ψb can be saved.

Further, when the processing unit 2 uses two waveform data Dwa and Dwb having different values from the acquired waveform data Dw ₁ (or waveform data Dw ₂ ) for 1/4 cycle in the second parameter calculation process. Alternatively, a configuration using two waveform data Dwa and Dwb that maximize the difference between the two can be adopted. According to this configuration, it is possible to reduce the calculation error that occurs in each parameter of the amplitudes A ₁ and A ₂ and the offsets M ₁ and M ₂ calculated in the second parameter calculation process.

Further, the above-mentioned electricity amount measuring device 11 adopts a configuration in which the current value I1, the voltage value V1, the power value W1 and the impedance Z are calculated as the amount of electricity for the DUT to be measured, but the current value I1 and the voltage It is also possible to adopt a configuration in which any one, any two, or any three of the value V1, the power value W1, and the impedance Z are measured as the amount of electricity. Further, in this case, when the amount of electricity to be measured is only the current value I1, the voltage detection unit 14 and the A / D conversion unit 16 in FIG. 1 can be omitted, and when the amount of electricity to be measured is only the voltage value V1. The current detection unit 13 and the A / D conversion unit 15 in FIG. 1 can be omitted.

Further, in the above example, the processing unit 2 adopts a configuration in which the initial phase θ _φ1 (θ ₄₅ ) is calculated as the tentative initial phase θx based on the above equation (7), but based on the above equation (8). , It is also possible to adopt a configuration in which the initial phase θ _φ2 (θ ₋₄₅ ) is calculated as the temporary initial phase θx.

Further, as the combination of the initial phases φ1 and φ2, in addition to the combination of 45 degrees and −45 degrees described above, each combination of 135 degrees and 45 degrees, 225 degrees and 135 degrees, 315 degrees (-45 degrees) and 225 degrees is used. Although it can be used, when the combination of 135 degrees and 45 degrees is used, the tentative initial phase θx is calculated based on any of the above equations (9) and (10), and the 225 degrees and 135 degrees are also used. In the case of a combination, the tentative initial phase θx is calculated based on one of the above equations (7) and (8), and in the case of a combination of 315 degrees (−45 degrees) and 225 degrees, the above equation ( The tentative initial phase θx can be calculated based on any one of 9) and (10).

1 Parameter calculation device 2 Processing unit 3 Storage unit 11 Electricity measurement device A ₁ , A ₂ Amplitude Drw ₁ First reference waveform data Drw ₂ Second reference waveform data Dw ₁ , Dw ₂ Waveform data M ₁ , M ₂ Offset x ₁ , X ₂ Sine wave signal to be measured θ ₁ , θ ₂ Initial phase

Claims (7)

Based on the waveform data Dw for 1/4 cycle acquired for the sine wave signal x (= Asin (2πft) + M) whose frequency f is known and whose amplitude A and offset M are unknown, the measurement is performed at the time of acquisition. It is a parameter calculation device that calculates each parameter of the initial phase θ (θ is a value within the angle range of 2π of −π / 4 or more and 7π / 4 or less), the amplitude A, and the offset M for the sinusoidal signal x. hand,
The initial phase φ of the reference sine wave signal y (= Bsin (2πft + φ) + N) of the initial phase φ having the frequency f and the amplitude B and the offset N are known is φ1 (φ1 is π / 4, 3π / 4). The first reference waveform data Drw ₁ for 1/4 cycle of the first reference sine wave signal y _φ1 (= Bsin (2πft + φ1) + N) as one of 5, 5π / 4 and 7π / 4). , And the second reference sine wave signal y _φ2 (= Bsin (2πft + φ2) + N) in which the initial phase φ of the reference sine wave signal y is φ2 (= φ1-π / 2). A storage unit in which the reference waveform data Drw ₂ is stored in advance and a processing unit are provided.
The processing unit
Based on the waveform data Dw for the 1/4 cycle and the first reference waveform data Drw ₁ for the 1/4 cycle, the sine wave signal x (= Asin (2πft + θ)) represented by the waveform data Dw. The first correlation coefficient calculation process for calculating the first correlation coefficient r _φ1 between + M) and the first reference sine wave signal y _φ1 and
Based on the waveform data Dw for the 1/4 cycle and the second reference waveform data Drw ₂ for the 1/4 cycle, the sine wave signal x (= Asin (2πft + θ) + M) and the second reference sine wave are measured. a second correlation coefficient calculation processing of calculating a second correlation coefficient r _.phi.2 of the wave signal y _.phi.2,
The correlation coefficient r of the following equation (1) showing the correlation coefficient r between the sine wave signal x (= Asin (2πft + θ) + M) to be measured and the reference sine wave signal y (= Bsin (2πft + φ) + N) is used. The process of calculating the first initial phase θ _φ1 with the first correlation coefficient r _φ1 and the initial phase φ of the equation (1) being the _φ1 and the correlation coefficient r of the equation (1) being the first. 2 The first initial phase θ _φ1 and the first initial phase θ _φ1 and the first phase are executed by executing any of the processes of calculating the second initial phase θ _φ2 with the correlation coefficient r _φ2 and the initial phase φ of the equation (1) being the φ2. 2 Temporary initial phase calculation processing that calculates any of the initial phase θ _φ2 as the temporary initial phase θx, and
The correlation coefficient r calculated when the initial phase θ of the following equation (1) is changed to φ1 and the initial phase θ of the equation (1) is changed from −π / 4 to 7π / 4 within the angle range. The polarity for each angle range of π / 2 and the initial phase φ of the following equation (1) are set to φ2, and the initial phase θ of the equation (1) is changed from −π / 4 to 7π / 4 within the angle range. The first correlation coefficient r _φ1 and the second phase from among the four combinations of the polarity of each π / 2 angle range of the correlation coefficient r calculated at that time and each of the π / 2 angle ranges. One combination matching each polarity combination of the relation number r _φ2 is specified, and the conversion formula associated with the specified one combination among the conversion formulas previously associated with each of the four combinations is described above. The first parameter calculation process of converting the tentative initial phase θx to calculate the initial phase θ, and
Arbitrary two waveform data Dwa and Dwb having different values among the calculated initial phase θ and the waveform data Dw for the 1/4 cycle, and the 1/4 cycle of the two waveform data Dwa and Dwb. Second parameter calculation for calculating the amplitude A and the offset M from the simultaneous equations of the following equations (2) and (3) defined by the phase differences ψa and ψb defined by the phase differences ψa and ψb from the first waveform data Dwst of the waveform data Dw of A parameter calculation device that executes processing.
r = (Dcos (θ-φ) -Csin (θ + φ)) / (√ (D-Csin2θ) √ (D-Csin2φ)) ... (1)
^{However, C = 4 / π 2 -1} / π, a ^{D = 1 / 2-4 / π 2} .
Dwa = Asin (ψa + θ) + M ・ ・ ・ (2)
Dwb = Asin (ψb + θ) + M ・ ・ ・ (3) When the waveform data Dwst and the last waveform data Dwen of the waveform data Dw for the quarter period have different values, the processing unit performs the two waveform data Dwa in the second parameter calculation process. The parameter calculation device according to claim 1, wherein the waveform data Dwst and the waveform data Dwen are used as Dwb, and the values 0 and π / 2 are used as the phase differences ψa and ψb. Based on the waveform data Dw for 1/4 cycle acquired for the sine wave signal x (= Asin (2πft) + M) whose frequency f is known and whose amplitude A and offset M are unknown, the measurement is performed at the time of acquisition. It is a parameter calculation method for calculating each parameter of the initial phase θ (θ is a value within the angle range of 2π of −π / 4 or more and 7π / 4 or less), the amplitude A, and the offset M for the sinusoidal signal x. hand,
The initial phase φ of the reference sine wave signal y (= Bsin (2πft + φ) + N) of the initial phase φ having the frequency f and the amplitude B and the offset N are known is φ1 (φ1 is π / 4, 3π / 4). The first reference waveform data Drw ₁ for 1/4 cycle of the first reference sine wave signal y _φ1 (= Bsin (2πft + φ1) + N) as one of 5, 5π / 4 and 7π / 4). , And the second reference sine wave signal y _φ2 (= Bsin (2πft + φ2) + N) in which the initial phase φ of the reference sine wave signal y is φ2 (= φ1-π / 2). 2 Reference Using the waveform data Drw ₂ ,
Based on the waveform data Dw for the 1/4 cycle and the first reference waveform data Drw ₁ for the 1/4 cycle, the sine wave signal x (= Asin (2πft + θ)) represented by the waveform data Dw. The first correlation coefficient calculation process for calculating the first correlation coefficient r _φ1 between + M) and the first reference sine wave signal y _φ1 and
Based on the waveform data Dw for the 1/4 cycle and the second reference waveform data Drw ₂ for the 1/4 cycle, the sine wave signal x (= Asin (2πft + θ) + M) and the second reference sine wave are measured. a second correlation coefficient calculation processing of calculating a second correlation coefficient r _.phi.2 of the wave signal y _.phi.2,
The correlation coefficient r of the following equation (1) showing the correlation coefficient r between the sine wave signal x (= Asin (2πft + θ) + M) to be measured and the reference sine wave signal y (= Bsin (2πft + φ) + N) is used. The process of calculating the first initial phase θ _φ1 with the first correlation coefficient r _φ1 and the initial phase φ of the equation (1) being the _φ1 and the correlation coefficient r of the equation (1) being the first. 2 The first initial phase θ _φ1 and the first initial phase θ _φ1 and the first phase are executed by executing any of the processes of calculating the second initial phase θ _φ2 with the correlation coefficient r _φ2 and the initial phase φ of the equation (1) being the φ2. 2 Temporary initial phase calculation processing that calculates any of the initial phase θ _φ2 as the temporary initial phase θx, and
The correlation coefficient r calculated when the initial phase θ of the following equation (1) is changed to φ1 and the initial phase θ of the equation (1) is changed from −π / 4 to 7π / 4 within the angle range. The polarity for each angle range of π / 2 and the initial phase φ of the following equation (1) are set to φ2, and the initial phase θ of the equation (1) is changed from −π / 4 to 7π / 4 within the angle range. The first correlation coefficient r _φ1 and the second phase from among the four combinations of the polarity of each π / 2 angle range of the correlation coefficient r calculated at that time and each of the π / 2 angle ranges. One combination matching each polarity combination of the relation number r _φ2 is specified, and the conversion formula associated with the specified one combination among the conversion formulas previously associated with each of the four combinations is described above. The first parameter calculation process of converting the tentative initial phase θx to calculate the initial phase θ, and
Arbitrary two waveform data Dwa and Dwb having different values among the calculated initial phase θ and the waveform data Dw for the 1/4 cycle, and the 1/4 cycle of the two waveform data Dwa and Dwb. Second parameter calculation for calculating the amplitude A and the offset M from the simultaneous equations of the following equations (2) and (3) defined by the phase differences ψa and ψb defined by the phase differences ψa and ψb from the first waveform data Dwst of the waveform data Dw of A method of calculating parameters to execute processing.
r = (Dcos (θ-φ) -Csin (θ + φ)) / (√ (D-Csin2θ) √ (D-Csin2φ)) ... (1)
^{However, C = 4 / π 2 -1} / π, a ^{D = 1 / 2-4 / π 2} .
Dwa = Asin (ψa + θ) + M ・ ・ ・ (2)
Dwb = Asin (ψb + θ) + M ・ ・ ・ (3) When the waveform data Dwst and the last waveform data Dwen of the 1/4 cycle waveform data Dw have different values, the waveforms are referred to as the two waveform data Dwa and Dwb in the second parameter calculation process. The parameter calculation method according to claim 3, wherein the data Dwst and the waveform data Dwen are used, and the values 0 and π / 2 are used as the respective phase differences ψa and ψb. A current detector that detects the sine wave current flowing through the object to be measured and outputs current waveform data for the sine wave current.
The current waveform data for 1/4 cycle of the current waveform data is acquired as the waveform data Dw, and the initial phase θ, the amplitude A, and the sine wave current of the sine wave current as the measured sine wave signal x are obtained. The parameter calculation device according to claim 1 or 2, which calculates each parameter of the offset M, and
An electric quantity measuring device including a measuring unit that measures a current value of the sinusoidal current as an electric quantity to be measured by using the calculated initial phase θ, the amplitude A, and the offset M. A voltage detector that detects the sine wave voltage generated in the object to be measured and outputs voltage waveform data about the sine wave voltage.
The voltage waveform data for 1/4 cycle of the voltage waveform data is acquired as the waveform data Dw, and the initial phase θ, the amplitude A, and the sine wave voltage of the sine wave voltage to be measured x are obtained. The parameter calculation device according to claim 1 or 2, which calculates each parameter of the offset M,
An electric energy measuring device including a measuring unit that measures a voltage value of the sinusoidal voltage as an electric energy of the object to be measured by using the calculated initial phase θ, the amplitude A, and the offset M. A current detector that detects the sine wave current flowing through the object to be measured and outputs current waveform data for the sine wave current.
A voltage detection unit that detects the sine wave voltage generated in the sine wave target when the sine wave current is flowing through the target to be measured and outputs voltage waveform data about the sine wave voltage.
The parameter calculation device according to claim 1 or 2,
Equipped with a measuring unit
The parameter calculation device acquires current waveform data for 1/4 cycle of the current waveform data as the waveform data Dw, and the initial phase of the sine wave current as the sine wave signal x to be measured. Each parameter of θ, the amplitude A and the offset M is calculated, and the voltage waveform data for 1/4 cycle of the voltage waveform data is acquired as the waveform data Dw to obtain the measured sine wave signal x. Each parameter of the initial phase θ, the amplitude A, and the offset M with respect to the sinusoidal voltage as
The measuring unit has the parameters of the initial phase θ, the amplitude A and the offset M for the calculated sinusoidal current, and the initial phase θ, the amplitude A and the said for the calculated sinusoidal voltage. An electric amount measuring device that measures at least one of the power value supplied to the measured object and the impedance of the measured object as the electric amount of the measured object based on each parameter of the offset M.

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