JP5489238B2 - Power measuring apparatus, power measuring method and program - Google Patents

Description

  The present invention relates to a power measurement device, a power measurement method, and a program.

  In general, the measurement of electric power consumed by an electric device connected to an AC power source is a current that changes with time, such as an electronic wattmeter as described in Patent Document 1, 4 or 5, for example. This is done by measuring the voltage and calculating the instantaneous power from it. For this reason, the wattmeter requires both a current measurement circuit and a voltage measurement circuit connected to the AC power supply line.

  In electrical equipment connected to an AC power supply, instantaneous power fluctuates in accordance with the phase of the voltage, and therefore, power is generally calculated by averaging over one cycle of the power supply voltage. When power is measured in a short time such as the cycle of the power supply voltage, it is necessary to know the time of one cycle of the power supply voltage. For example, in the electronic wattmeter of Patent Document 1, one cycle of the AC voltage is detected by the zero cross of the AC voltage.

  In the electric energy measuring device of Patent Document 3, voltage measurement of an electric device to be measured is performed in advance, and a phase difference from a predetermined reference AC power source is stored in the wattmeter. During power measurement, by calculating the power from the voltage obtained by shifting the voltage of the reference AC power supply by the stored phase difference and the measured current, the voltage measurement circuit can be omitted from the wattmeter and the circuit scale can be reduced. Yes. Moreover, in the electric power monitoring system of patent document 2, a power factor is previously measured and memorize | stored per breaker. During power measurement, the power is calculated from the measured current, the rated voltage determined for each breaker, and the stored power factor, eliminating the voltage measurement circuit from the power meter and reducing the circuit scale. ing.

  As a method for measuring the current, for example, Patent Document 6 describes that an induced voltage signal detected by a coil is integrated to obtain an instantaneous value of the current. In the current sensor circuit for a coil of Patent Document 6, the induced voltage signal is integrated by a plurality of integrating means having different initial values by a predetermined value, and output is performed by sequentially switching from a large initial value integrating means every predetermined time. The offset component is converted into a periodic waveform having a period N times that of the signal under measurement. In addition, Patent Document 7 describes that a power failure is determined when the inversion period of H and L of the zero-cross signal of the voltage waveform is out of the normal range.

JP 2000-338148 A JP 2008-089436 A JP 2009-168586 A JP 2009-222433 A JP 2009-288218 A JP 2010-008340 A JP 2010-237120 A

  As in Patent Document 1 or 5, the wattmeter generally requires both a current measurement circuit and a voltage measurement circuit connected to the AC power supply line, and there is a problem that the circuit scale increases.

  Both of the wattmeters of Patent Document 2 and Patent Document 3 calculate power based on a phase difference and a power factor measured in advance, so that the electric device to be measured is changed or the same device. However, there is a problem that power cannot be calculated correctly when there is a change in the power factor due to a change in the operating state. Furthermore, in the case of the wattmeter of Patent Document 3, when there is a change in the reference AC power supply, the voltage generated by the phase shift also fluctuates therefrom, so that the power cannot be calculated correctly. There is.

  The present invention has been made in view of the circumstances as described above, and can reduce the circuit scale of the voltage measuring device, and can change the electric device to be measured and can follow the load fluctuation, the power measuring method, the power measuring method, and the program The purpose is to provide.

The power measuring device according to the first aspect of the present invention is:
A cross point detection means for detecting a positive cross point where the voltage of the electric device crosses the reference potential from negative to positive, or a negative cross point which crosses the reference potential from positive to negative;
Current measuring means for measuring an instantaneous current value of the electric device;
A voltage value generating means for generating an instantaneous voltage value from a sine wave whose time axis is adjusted by applying a reference point of a sine wave having a predetermined peak value to the positive cross point or the negative cross point;
The instantaneous voltage value generated by the voltage value generating means is multiplied by the instantaneous current value at the same time, and the multiplied value is averaged over the time between the adjacent positive cross points or the negative cross points. Power calculating means for calculating a value;
Equipped with a,
The cross point detecting means detects the positive cross point and the negative cross point,
The voltage value generating means adjusts a time axis and a DC voltage component in accordance with an interval between the positive cross point and the negative cross point of the sine wave having the predetermined peak value, and generates an instantaneous voltage value.
It is characterized by that.

The power measurement method according to the second aspect of the present invention is:
An electric power measurement method performed by an apparatus for measuring electric power of an electric device,
A cross point detection step of detecting a positive cross point where the voltage of the electrical device crosses the reference potential from negative to positive, or a negative cross point which crosses the reference potential from positive to negative;
A current measuring step for measuring an instantaneous current value of the electric device;
Applying a reference point of a sine wave having a predetermined peak value to the positive cross point or the negative cross point, a voltage value generating step for generating an instantaneous voltage value from a sine wave whose time axis is adjusted,
The instantaneous voltage value generated in the voltage value generation step is multiplied by the instantaneous current value at the same time, and the multiplied value is averaged over the time between the adjacent positive cross points or the negative cross points to obtain power. A power calculating step for calculating a value;
Equipped with a,
In the cross point detection step, the positive cross point and the negative cross point are detected,
In the voltage value generation step, the instantaneous voltage value is generated by adjusting the time axis and the DC voltage component in accordance with the interval between the positive cross point and the negative cross point of the sine wave of the predetermined peak value,
It is characterized by that.

According to a third aspect of the present invention, there is provided a program for detecting a cross point detection in which a computer detects a positive cross point where a voltage of an electrical device crosses a reference potential from negative to positive, or a negative cross point which crosses the reference potential from positive to negative Steps,
A current measuring step for measuring an instantaneous current value of the electric device;
Applying a reference point of a sine wave having a predetermined peak value to the positive cross point or the negative cross point, a voltage value generating step for generating an instantaneous voltage value from a sine wave whose time axis is adjusted,
The instantaneous voltage value generated in the voltage value generation step is multiplied by the instantaneous current value at the same time, and the multiplied value is averaged over the time between the adjacent positive cross points or the negative cross points to obtain power. A power calculating step for calculating a value;
Was executed,
In the cross point detection step, the positive cross point and the negative cross point are detected,
In the voltage value generation step, the instantaneous voltage value is generated by adjusting the time axis and the DC voltage component in accordance with the interval between the positive cross point and the negative cross point of the sine wave of the predetermined peak value,
It is characterized by that.

  Since the power measurement device of the present invention is configured to use a zero-cross detection circuit having a smaller scale than the voltage measurement circuit instead of the voltage measurement circuit, the circuit scale for voltage measurement can be reduced, and Because it is configured to detect the zero-crossing point of the voltage waveform, it can accurately grasp the phase difference between current and voltage and calculate correct power even when there is a change in the electrical equipment to be measured or load fluctuations. It becomes possible.

It is a block diagram which shows the structural example of the electric power measurement apparatus which concerns on Embodiment 1 of this invention. 3 is a diagram illustrating an example of a configuration for performing zero-cross detection according to Embodiment 1. FIG. It is a figure explaining an example of the operation | movement which detects a zero cross point from a voltage waveform and calculates electric power. 3 is a flowchart illustrating an example of power measurement operation according to the first embodiment. It is a figure explaining an example of the operation | movement which produces | generates the voltage waveform which concerns on Embodiment 2 of this invention. 6 is a flowchart illustrating an example of power measurement operation according to the second embodiment. It is a block diagram which shows the structural example of the electric power measurement apparatus which concerns on Embodiment 3 of this invention. 10 is a flowchart illustrating an example of an operation for changing a peak value according to the third embodiment. It is a block diagram which shows an example of the hardware constitutions of the electric power measurement apparatus which concerns on embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or equivalent parts are denoted by the same reference numerals.

(Embodiment 1)
FIG. 1 is a block diagram illustrating a configuration example of a power measurement device according to Embodiment 1 of the present invention. The power measuring device is connected to a power line between the AC power source 1 and the electric device 2. The power measurement device 10 includes a zero cross detection unit 11, a voltage value generation unit 12, a current measurement unit 13, a power calculation unit 15, and an output unit 16.

  The zero cross detection unit 11 is connected to each of the power lines. The zero-cross detection unit 11 detects a positive cross point where the voltage of the power line crosses the reference potential from negative to positive (typically a neutral potential of 0 V) or a negative cross point where the reference potential crosses the reference potential from positive to negative.

  The voltage value generation unit 12 holds sine wave data having a predetermined peak value. Apply the sine wave reference point to the adjacent positive cross point (or negative cross point) detected by the zero cross point detector, and adjust the time axis of the sine wave to calculate the voltage waveform of the sine wave (calculation formula) ) Is generated. When the zero-cross detection reference potential is a neutral potential of 0 V, the sine wave reference point is a point of 0 radians and 2π radians (or π radians).

  On the other hand, the current measuring unit 13 measures the current flowing through the power line. For example, the current measurement unit 13 detects a magnetic field generated by the current flowing through the power line by the current sensor 14 and measures the current. The current measurement unit 13 can be realized using, for example, a clamp-type current sensor or a shunt resistor.

  The voltage value generation unit 12 generates a voltage value (instantaneous voltage value) at that time from the zero cross point and the generated sine wave in accordance with the timing of current measurement, and supplies the voltage value to the power calculation unit 15. The power calculation unit 15 multiplies the instantaneous current value measured by the current measurement unit 13 and the instantaneous voltage value supplied from the voltage value generation unit 12 to calculate an instantaneous power value.

  The power calculator 15 calculates the power value by averaging the instantaneous power value over one period of the voltage. One period of the voltage is given by the time between two adjacent positive cross points (or negative cross points). The power calculation unit 15 sends the calculated power value to the output unit 16. The output unit 16 transmits the power value to another display device or storage device. Alternatively, the output unit 16 may include a display device and display the power value.

  FIG. 2 is a diagram illustrating an example of a configuration for performing zero-cross detection according to the first embodiment. For example, as shown in FIG. 2, the zero-cross detection unit 11 can be realized by combining a comparator 31 and a rising edge detection circuit 32 that are generally well-known electronic circuits. When the connection in FIG. 2 detects a positive cross point, a negative cross point is detected if the line connecting the power line to the comparator 31 is replaced. The zero cross detector 11 detects a positive cross point or a negative cross point without detecting a voltage.

  FIG. 3 is a diagram illustrating an example of an operation for detecting a zero-cross point from a voltage waveform and calculating power. The voltage waveform of the AC power supply 1 has, for example, a sine waveform as shown by the voltage waveform 401 in FIG. When the voltage waveform 401 is given to the comparator 31 of FIG. 2 as an input, the output of the comparator 31 is positive in the interval where the voltage takes a positive value in the voltage waveform 401. In the interval where the voltage waveform 401 takes a negative value, the output of the comparator 31 is negative (comparator output 402 in FIG. 3).

  Next, when the output of the comparator 31 (comparator output 402) is given as the input of the rising edge detection circuit 32, a pulse is output at the rising edge portion of the comparator output waveform (edge detection output 403 in FIG. 3). The pulse of the edge detection output 403 output by the above operation corresponds to the moment when the voltage of the AC power supply 1 (the line connected to the + terminal of the comparator 31) changes from a negative value to a positive value. . In the configuration of FIG. 2, the positive cross point is detected by the pulse of the edge detection output 403. The interval between adjacent pulses is the period T of the voltage waveform.

  A voltage waveform such as the voltage waveform 401 in FIG. 3 can be generated by adjusting the time axis by matching a reference point of a sine wave having a predetermined peak value to the pulse of the edge detection output 403. The predetermined peak value is a value set in advance according to the voltage of the AC power supply. Although the power measuring device 10 does not measure a voltage, a voltage waveform (calculation formula) that approximates the voltage waveform 401 of the AC power supply can be generated from a positive cross point or a negative cross point and a sine wave having a predetermined peak value. it can.

  The current measurement unit 13 detects an induced magnetic field generated by a current at a predetermined sampling period, for example, and generates a current value. For example, the current has a waveform as indicated by a current 406 in the second stage from the bottom of FIG. Actually, it is detected by a discrete value of the sampling period.

ここでＶ_０は、予め電力計測装置１０に設定された交流電源１の電圧の実効値（以下、実効電圧という）で、例えば、１００Ｖといった値となる。Δｔはサンプリング周期、ｎは正クロス点からのサンプリング数、Ｔは交流電圧の周期である。一般に交流電源の公称電圧は、電圧の実効値で与えられるので、慣例に従って数１のように実効値Ｖ_０で表している。実質的には所定の波高値が与えられているのと等価である。瞬時電圧値を計算するときに実効電圧（実効値）から波高値に換算してもよいし、予め波高値で設定してもよい。 The voltage value generation unit 12 generates a voltage waveform value at a time corresponding to the time from the positive cross point (or negative cross point) to the sampling as an instantaneous voltage value in accordance with the sampling period of the current measurement unit 13. . The voltage value generator 12 calculates the instantaneous voltage value V according to the equation shown in Equation 1.

Here, V ₀ is an effective value (hereinafter referred to as effective voltage) of the voltage of the AC power source 1 set in the power measuring device 10 in advance, and is a value such as 100 V, for example. Δt is the sampling period, n is the number of samplings from the positive cross point, and T is the period of the AC voltage. In general, the nominal voltage of the AC power supply is given by the effective value of the voltage, and is expressed by the effective value V ₀ as shown in Equation 1 according to the convention. This is substantially equivalent to a given peak value being given. When calculating the instantaneous voltage value, the effective voltage (effective value) may be converted into a peak value, or may be set in advance as a peak value.

  Next, the power calculator 15 calculates and integrates the instantaneous power amount from the measured instantaneous current value and the calculated instantaneous voltage value. Specifically, for example, when the measured current value is I and the calculated voltage is V, the instantaneous electric energy can be calculated by V × I × Δt. A power waveform 407 is schematically shown at the bottom of FIG. The power waveform 407 in FIG. 3 corresponds to the voltage waveform 401 and the current 406 thereabove. The instantaneous power amount is represented by a value obtained by adding a sign to the area of a rectangular region having a width of the sampling period Δt and the height of the value of the power waveform at that time.

  When integrating the instantaneous power amount for one cycle of the power supply voltage, the power calculation unit 15 divides the accumulated one cycle power amount by the cycle T to calculate the average power for one cycle. The power calculation unit 15 sends the calculated average power to the output unit 16 as the power value of the cycle.

  In general, particularly in the case of commercial power, the voltage and waveform of the power supply are stable, and the voltage is mainly determined by the distribution path. Factors that determine the electric power of an electrical device are dominated by the phase difference between current and voltage and the current waveform. The voltage changes beyond the error range when there is a power failure, instantaneous voltage drop, or when a load (high current consumption) exceeding the specified value is connected to the power distribution system. When a large current flows through the distribution system, it is interrupted by a breaker that protects the system. Therefore, in normal use of electric equipment, if the phase difference between the current and the voltage and the current waveform are measured, the power can be measured within the voltage error range. When connecting electrical equipment, it is more accurate if the crest value is set to measure the power supply voltage and calculate the voltage waveform.

  In the present embodiment, a single-phase two-wire AC power source is assumed as the AC power source. The power measurement apparatus 10 according to the first embodiment can perform power measurement in the same procedure even in the case of a single-phase three-wire type or a three-phase three-wire type AC power supply.

  FIG. 4 is a flowchart illustrating an example of the power measurement operation according to the first embodiment. When the power measuring apparatus 10 starts operating, first, the zero-cross detector 11 detects the rising edge of the comparator output as described above, and the first positive cross point (positive cross point 404 in FIG. 3) of the voltage waveform of the AC power supply 1. Hereinafter, this is described as a first positive cross point) (step S10). The zero-cross detector 11 detects the next positive cross point (the positive cross point 405 in FIG. 3, hereinafter referred to as a second positive cross point) by the same operation procedure as in step 201 (step S11). The first positive cross point and the second positive cross point are adjacent to each other, and the interval is a period T.

  The voltage value generation unit 12 calculates an elapsed time (period T) between the detected first and second positive cross points (step S12). The voltage value generation unit 12 adjusts the time axis of the sine wave having a predetermined peak value according to the positive cross point and the period T to generate a voltage waveform (calculation formula) of the sine wave (step S13).

  The power calculator 15 initially sets the periodic power amount to 0 (step S14). Then, the zero-cross detection unit 11 detects the next zero-cross point by the same operation procedure as in step 201 (step S15). Thereafter, the processing from step S16 to step S19 in FIG. 4 is repeated at regular time intervals (in the following description, Δt) while the period T elapses from the detection time of the positive cross point.

  First, the current measuring unit 13 measures the current value I as described above (step S16). The power calculation unit 15 calculates the voltage value V according to the equation shown in Equation 1 using the calculated period T and time interval Δt (step S17). Here, n is a loop counter, and holds the number of times when the power calculation unit 15 repeatedly executes the processing from step S16 to step S19. For example, initially n = 0, and from step S16 to step S19. N = 1, n = 2,. . . And so on.

  Next, the power calculation unit 15 calculates the instantaneous power amount from the current value measured in step S16 and the voltage value calculated in step S17, and integrates it into the periodic power amount (step S18). The processes from S16 to S18 described above are repeated until one cycle ends while increasing the loop counter n (step S19; NO).

  When the processing for one cycle is completed (step S19; YES), the power calculation unit 15 calculates the average power for one cycle by dividing the periodic power amount by the cycle T, and transmits the calculation result to the output unit 16 (step S19). S20).

  After the process described above is completed, the process returns to step S14 again, and the process is repeated from the initial setting of the periodic power amount. When returning to step S14, the loop counter n is reset to zero.

  As described above, in the first embodiment, the case where the zero cross detection unit 11 detects a positive cross point where the voltage waveform of the AC power supply 1 changes from a negative value to a positive value has been described. The power measuring device 10 may detect a negative cross point where the voltage changes from a positive value to a negative value. Alternatively, both the positive cross point and the negative cross point may be detected.

  Further, in the process of step S19 in FIG. 4, the number of loop repetitions for performing the process from step S16 to step S19 is determined by the period of one cycle of the voltage waveform, but the period of N cycles (N is 1 or more) (Integer value) or M seconds (M is a positive real value).

In addition, the output unit 16 may not only display the received average power as it is, but also display it as an accumulated power amount. Alternatively, the electric power amount may be converted into an electric charge or CO ₂ emission amount and displayed according to a known calculation formula.

In the first embodiment, the period T is dynamically calculated at the time of power measurement in the processing from step S10 to step S12 in FIG. 4. However, similarly to the effective voltage V ₀ , the power measurement of the present embodiment is performed in advance. It may be set in the apparatus 10.

  In Embodiment 1, the value obtained at the start of power measurement is continuously used in the subsequent processing in the period T. However, every time the power calculation process is executed a certain number of times, every predetermined time, or The processing from step S10 to step S12 in FIG. 4 may be re-executed at a random timing to be obtained again.

  Since the power measurement device 10 of the present embodiment is configured to calculate power using a zero-cross detection circuit having a smaller scale than the voltage measurement circuit instead of the voltage measurement circuit, the circuit scale of the power measurement device 10 There is an effect that can be made smaller.

  In addition, it is configured to detect the zero cross point of the voltage waveform and calculate the power, so even if there is a change in the electrical equipment to be measured or there is a load change, the phase difference between the current and voltage can be accurately grasped. There is also an effect that correct power can be calculated.

(Embodiment 2)
The power measuring apparatus 10 according to the second embodiment detects both the positive cross point and the negative cross point. Then, the instantaneous voltage value is generated by adjusting the time axis and the DC voltage component in accordance with the sine wave having a predetermined peak value in accordance with the interval between the positive cross point and the negative cross point.

  FIG. 5 is a diagram illustrating an example of an operation for generating a voltage waveform according to the second embodiment of the present invention. In the power measurement device 10 of the second embodiment, the zero cross point detection unit detects both the positive cross point and the negative cross point. For example, if two comparator circuits of FIG. 2 are provided and the + terminal and the − terminal are connected in reverse, one can detect the positive cross point and the other can detect the negative cross point. Alternatively, two rising edge detection circuits 32 are provided, and the output of the comparator is input to one as it is, and the output of the comparator is inverted and input to the other, so that one is a positive cross point and the other is a negative cross point. Can be detected.

  The voltage value generation unit 12 adjusts the time axis and the DC voltage so that a sine wave having a predetermined peak value matches both the positive cross point and the negative cross point. For example, as shown in FIG. 5, when the time from the positive cross point to the next negative cross point is different from the time from the negative cross point to the next positive cross point, first, the adjacent positive cross point (or negative cross point) The time axis (period T) of the sine wave is adjusted so that the time between the sine wave becomes the period T of the sine wave. Next, the DC component of the voltage is determined so that the positive interval of the voltage waveform becomes equal during the time from the positive cross point to the next negative cross point. That is, the sine wave is shifted in the voltage direction (vertical direction in FIG. 5). Then, the phase is adjusted so that the point where the voltage of the shifted voltage waveform crosses 0V from negative to positive coincides with the positive cross point.

  Based on the voltage waveform generated by adjusting a predetermined sine wave as described above, the voltage value generation unit 12 generates a voltage value at that timing in accordance with the timing at which the current measurement unit 13 measures the current. . The current measurement unit 13 measures the instantaneous current value as in the first embodiment. In this case, it is desirable that the current can be measured including the DC component.

  As in the first embodiment, the power calculation unit 15 calculates an instantaneous power value from the instantaneous current value and the instantaneous voltage value, and averages the power value of one period of the voltage to calculate the power. As in the embodiment, the instantaneous power amount may be integrated for one period and divided by the period T to calculate the power value.

  FIG. 6 is a flowchart illustrating an example of the power measurement operation according to the second embodiment. In the power measurement device 10 of the second embodiment, first, the zero-cross detection unit 11 detects the rising edge of the comparator output as in the first embodiment and detects the first positive cross point (hereinafter referred to as the first cross point) of the voltage waveform of the AC power supply 1. 1 is described (step S21). The zero cross point detector detects the negative cross point following the positive cross point as described above (step S22). The zero cross detection unit 11 detects the next positive cross point (hereinafter referred to as a second positive cross point) by the same operation procedure as in step 201 (step S23). The first positive cross point and the second positive cross point are adjacent to each other, and the interval is a period T.

  The voltage value generation unit 12 calculates an elapsed time (period T) between the detected first and second positive cross points (step S24). The voltage value generation unit 12 adjusts the time axis and the DC voltage component so that the sine wave having a predetermined peak value matches both the positive cross point and the negative cross point, and the voltage waveform of the sine wave (calculation formula) Is generated (step S25). Hereinafter, the operations from the initial setting of the periodic power amount in steps S26 to S32 to the calculation and output of the average power are the same as those in steps S14 to S20 in FIG.

  According to the power measurement device 10 of the second embodiment, even when the power supply voltage includes a DC component, if the AC voltage is a sine wave, the power can be measured without measuring the voltage.

(Embodiment 3)
FIG. 7 is a block diagram illustrating a configuration example of the power measurement device according to the third embodiment of the present invention. The third embodiment includes means for changing and setting the peak value of the sine wave. The power measuring apparatus 10 according to the third embodiment includes an input unit 17 and a peak value setting unit 18 in addition to the configuration of the first embodiment.

  The input unit 17 receives an input of the effective voltage or peak value of the AC power supply. The input unit 17 may be configured to be able to input a numerical value with a numeric keypad, or may be configured with a switch for instructing increase / decrease and a display device. Moreover, you may comprise with a display and a touchscreen.

  The peak value setting unit 18 changes the peak value (or effective value) of the sine wave in accordance with the effective voltage or peak value input by the input unit 17 and stores the value. The voltage value generation unit 12 generates an instantaneous voltage value using the peak value (or effective value) changed and stored by the peak value setting unit 18. Other configurations and operations are the same as those in the first or second embodiment.

  FIG. 8 is a flowchart illustrating an example of the operation of changing the peak value according to the third embodiment. The input unit 17 waits for input of a peak value (or effective voltage) (step S41, step S42; NO). If there is an input of a crest value (or effective voltage) (step S42; YES), the crest value setting unit 18 adjusts the crest value (or effective value) of a sine wave according to the input crest value (or effective voltage). Is changed and stored (step S43). Then, return to the step and repeat from the standby for input.

  In general power supply, the power supply voltage supplied to electrical equipment may change due to changes in the distribution system, such as changing the transformer, changing the distance from the transformer, or changing the system connected to the transformer. . According to the power measurement device 10 of the third embodiment, even if the power supply voltage changes, the peak value of a sine wave that generates an instantaneous voltage value can be set accordingly. As a result, the electric power of the electric device can be measured more accurately.

  FIG. 9 is a block diagram illustrating an example of a hardware configuration of the power measurement device according to the embodiment of the present invention. As shown in FIG. 9, the power measuring device 10 includes a control unit 21, a main storage unit 22, an external storage unit 23, an operation unit 24, a display unit 25, an input / output unit 26, and a transmission / reception unit 27. The main storage unit 22, the external storage unit 23, the operation unit 24, the display unit 25, the input / output unit 26, and the transmission / reception unit 27 are all connected to the control unit 21 via the internal bus 20.

  The control unit 21 includes a CPU (Central Processing Unit) and the like, and executes processing for measuring power in accordance with the control program 19 stored in the external storage unit 23.

  The main storage unit 22 is composed of a RAM (Random-Access Memory) or the like, loads the control program 19 stored in the external storage unit 23, and is used as a work area of the control unit 21.

  The external storage unit 23 includes a non-volatile memory such as a flash memory, a hard disk, a DVD-RAM (Digital Versatile Disc Random-Access Memory), a DVD-RW (Digital Versatile Disc ReWritable), and controls processing of the power measuring apparatus 10. A program to be executed by the unit 21 is stored in advance, and data stored by the program is supplied to the control unit 21 in accordance with an instruction from the control unit 21, and the data supplied from the control unit 21 is stored.

  The operation unit 24 includes a pointing device such as a keyboard, a switch, and a touch panel, and an interface device that connects the keyboard, the switch, the pointing device, and the like to the internal bus 20. The operation unit 24 receives an input of a peak value or an effective voltage.

  The display unit 25 is composed of a CRT (Cathode Ray Tube), an LCD (Liquid Crystal Display), or the like, and displays a screen for outputting electric power and electric energy. The peak value or effective voltage setting value is also displayed.

  The input / output unit 26 includes a serial interface or a parallel interface. The input / output unit 26 is connected to a power line for detecting a zero cross point, the current sensor 14, and the like. The input / output unit 26 includes a circuit that detects a zero-cross point, for example, a comparator 31 and an edge detection circuit. In addition, a circuit for AD converting the output of the current sensor 14 is included.

  The power measuring device 10 includes a transmission / reception unit (not shown) when communicating the measured power and the amount of power to an external device. The transmission / reception unit includes a network termination device or a wireless communication device connected to the network, and a serial interface or a LAN (Local Area Network) interface connected to them. The transmission / reception unit is connected to an external terminal or a server via a network.

  The processing of the zero cross detection unit 11, the voltage value generation unit 12, the current measurement unit 13 and the power calculation unit 15, the output unit 16, the input unit 17, and the peak value setting unit 18 of the power measurement device 10 illustrated in FIGS. The control program 19 is executed by processing using the control unit 21, the main storage unit 22, the external storage unit 23, the operation unit 24, the display unit 25, the input / output unit 26, and the like as resources.

  In addition, the above-described hardware configuration and flowchart are examples, and can be arbitrarily changed and modified.

  The central part that performs the power measurement process including the control unit 21, the main storage unit 22, the external storage unit 23, the operation unit 24, the display unit 25, the input / output unit 26, and the internal bus 20 is a dedicated system. Regardless, it can be realized using a normal computer system. For example, a computer program for executing the above operation is stored and distributed in a computer-readable recording medium (flexible disk, CD-ROM, DVD-ROM, etc.), and the computer program is installed in the computer. Thus, the power measurement device 10 that executes the above-described processing may be configured. Alternatively, the power measurement device 10 may be configured by storing the computer program in a storage device included in a server on a communication network such as the Internet and downloading the computer program from a normal computer system.

  Further, when the function of the power measuring device 10 is realized by sharing an OS (operating system) and an application program, or by cooperation between the OS and the application program, only the application program portion is stored in a recording medium or a storage device. May be.

  It is also possible to superimpose a computer program on a carrier wave and distribute it via a communication network. For example, the computer program may be posted on a bulletin board (BBS, Bulletin Board System) on a communication network, and the computer program distributed via the network. The computer program may be started and executed in the same manner as other application programs under the control of the OS, so that the above-described processing may be executed.

  A part or all of the above-described embodiment can be described as in the following supplementary notes, but is not limited thereto.

(Appendix 1)
A cross point detection means for detecting a positive cross point where the voltage of the electric device crosses the reference potential from negative to positive, or a negative cross point which crosses the reference potential from positive to negative;
Current measuring means for measuring an instantaneous current value of the electric device;
A voltage value generating means for generating an instantaneous voltage value from a sine wave whose time axis is adjusted by applying a reference point of a sine wave having a predetermined peak value to the positive cross point or the negative cross point;
The instantaneous voltage value generated by the voltage value generating means is multiplied by the instantaneous current value at the same time, and the multiplied value is averaged over the time between the adjacent positive cross points or the negative cross points. Power calculating means for calculating a value;
A power measuring device comprising:

(Appendix 2)
The cross point detecting means detects the positive cross point and the negative cross point,
The voltage value generating means adjusts a time axis and a DC voltage component in accordance with an interval between the positive cross point and the negative cross point of the sine wave having the predetermined peak value, and generates an instantaneous voltage value.
The power measuring device according to Supplementary Note 1, wherein

(Appendix 3)
The power measurement device according to appendix 1 or 2, wherein the cross point detection means includes a comparator and an edge detection circuit.

(Appendix 4)
The power measuring device according to any one of appendices 1 to 3, further comprising: a power amount calculating unit that calculates a power amount of the electric device from a power value calculated by the power calculating unit.

(Appendix 5)
Input means for inputting a peak value of the sine wave;
Means for changing the predetermined peak value to a peak value input by the input means;
The power measuring device according to any one of appendices 1 to 4, characterized in that:

(Appendix 6)
An electric power measurement method performed by an apparatus for measuring electric power of an electric device,
A cross point detection step of detecting a positive cross point where the voltage of the electrical device crosses the reference potential from negative to positive, or a negative cross point which crosses the reference potential from positive to negative;
A current measuring step for measuring an instantaneous current value of the electric device;
Applying a reference point of a sine wave having a predetermined peak value to the positive cross point or the negative cross point, a voltage value generating step for generating an instantaneous voltage value from a sine wave whose time axis is adjusted,
The instantaneous voltage value generated in the voltage value generation step is multiplied by the instantaneous current value at the same time, and the multiplied value is averaged over the time between the adjacent positive cross points or the negative cross points to obtain power. A power calculating step for calculating a value;
An electric power measurement method comprising:

(Appendix 7)
The cross point detection step detects the positive cross point and the negative cross point,
The voltage value generation step adjusts a time axis and a DC voltage component in accordance with an interval between the positive cross point and the negative cross point of the sine wave of the predetermined peak value, and generates an instantaneous voltage value.
The power measurement method according to appendix 6, wherein:

(Appendix 8)
The power measurement method according to appendix 6 or 7, further comprising power amount calculation means for calculating a power amount of the electrical device from the power value calculated in the power calculation step.

(Appendix 9)
An input step of inputting a peak value of the sine wave;
Changing the predetermined peak value to the peak value input in the input step,
The power measuring method according to any one of appendices 6 to 8, characterized in that:

(Appendix 10)
A cross point detecting step for detecting a positive cross point where the voltage of the electrical device crosses the reference potential from negative to positive in the computer, or a negative cross point which crosses the reference potential from positive to negative;
A current measuring step for measuring an instantaneous current value of the electric device;
Applying a reference point of a sine wave having a predetermined peak value to the positive cross point or the negative cross point, a voltage value generating step for generating an instantaneous voltage value from a sine wave whose time axis is adjusted,
The instantaneous voltage value generated in the voltage value generation step is multiplied by the instantaneous current value at the same time, and the multiplied value is averaged over the time between the adjacent positive cross points or the negative cross points to obtain power. A power calculating step for calculating a value;
A program characterized by having executed.

  The present invention can be applied to the field of realizing a power measuring device capable of following a change of a measurement target or a load change while reducing a circuit scale of a voltage measuring unit.

DESCRIPTION OF SYMBOLS 1 AC power supply 2 Electric equipment 10 Electric power measurement apparatus 11 Zero cross detection part 12 Voltage value generation part 13 Current measurement part 14 Current sensor 15 Electric power calculation part 16 Output part 17 Input part 18 Crest value setting part 20 Internal bus 21 Control part 22 Main memory Unit 23 External storage unit 24 Operation unit 25 Display unit 26 Input / output unit 29 Control program 31 Comparator 32 Rising edge detection circuit

Claims (8)

A cross point detection means for detecting a positive cross point where the voltage of the electric device crosses the reference potential from negative to positive, or a negative cross point which crosses the reference potential from positive to negative;
Current measuring means for measuring an instantaneous current value of the electric device;
A voltage value generating means for generating an instantaneous voltage value from a sine wave whose time axis is adjusted by applying a reference point of a sine wave having a predetermined peak value to the positive cross point or the negative cross point;
The instantaneous voltage value generated by the voltage value generating means is multiplied by the instantaneous current value at the same time, and the multiplied value is averaged over the time between the adjacent positive cross points or the negative cross points. Power calculating means for calculating a value;
Equipped with a,
The cross point detecting means detects the positive cross point and the negative cross point,
The voltage value generating means adjusts a time axis and a DC voltage component in accordance with an interval between the positive cross point and the negative cross point of the sine wave having the predetermined peak value, and generates an instantaneous voltage value.
A power measuring device characterized by that. The power measurement device according to claim 1, wherein the cross point detection unit includes a comparator and an edge detection circuit. Wherein the power value calculated by the power calculation means, the power measuring apparatus according to claim 1 or 2, characterized in that it comprises an electric power calculation means for calculating the power of the electrical device. Input means for inputting a peak value of the sine wave;
Means for changing the predetermined peak value to a peak value input by the input means;
Power measurement apparatus according to any one of claims 1 to 3, characterized in that. An electric power measurement method performed by an apparatus for measuring electric power of an electric device,
A cross point detection step of detecting a positive cross point where the voltage of the electrical device crosses the reference potential from negative to positive, or a negative cross point which crosses the reference potential from positive to negative;
A current measuring step for measuring an instantaneous current value of the electric device;
Applying a reference point of a sine wave having a predetermined peak value to the positive cross point or the negative cross point, a voltage value generating step for generating an instantaneous voltage value from a sine wave whose time axis is adjusted,
The instantaneous voltage value generated in the voltage value generation step is multiplied by the instantaneous current value at the same time, and the multiplied value is averaged over the time between the adjacent positive cross points or the negative cross points to obtain power. A power calculating step for calculating a value;
Equipped with a,
In the cross point detection step, the positive cross point and the negative cross point are detected,
In the voltage value generation step, the instantaneous voltage value is generated by adjusting the time axis and the DC voltage component in accordance with the interval between the positive cross point and the negative cross point of the sine wave of the predetermined peak value,
A power measurement method characterized by that. The power measurement method according to claim 5 , further comprising: a power amount calculation unit that calculates a power amount of the electric device from the power value calculated in the power calculation step. An input step of inputting a peak value of the sine wave;
Changing the predetermined peak value to the peak value input in the input step,
The power measurement method according to claim 5 or 6 , wherein A cross point detecting step for detecting a positive cross point where the voltage of the electrical device crosses the reference potential from negative to positive in the computer, or a negative cross point which crosses the reference potential from positive to negative;
A current measuring step for measuring an instantaneous current value of the electric device;
Applying a reference point of a sine wave having a predetermined peak value to the positive cross point or the negative cross point, a voltage value generating step for generating an instantaneous voltage value from a sine wave whose time axis is adjusted,
The instantaneous voltage value generated in the voltage value generation step is multiplied by the instantaneous current value at the same time, and the multiplied value is averaged over the time between the adjacent positive cross points or the negative cross points to obtain power. A power calculating step for calculating a value;
Was executed,
In the cross point detection step, the positive cross point and the negative cross point are detected,
In the voltage value generation step, the instantaneous voltage value is generated by adjusting the time axis and the DC voltage component in accordance with the interval between the positive cross point and the negative cross point of the sine wave of the predetermined peak value,
A program characterized by that.

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