AU2014334295B2 - Measurement method and measurement circuit for power parameter - Google Patents

Abstract

Disclosed are a measurement method and measurement circuit for a power parameter. The measurement method comprises: adjusting the size of conduction angles, and acquiring a maximum voltage waveform value of a live line end or a load end at different conduction angles; dividing the maximum voltage waveform value at different conduction angles by a standard maximum waveform value of a corresponding conduction angle acquired at a standard voltage to obtain a voltage ratio at different conduction angles; according to the voltage ratio, acquiring voltage effective values and active power at different conduction angles; according to the voltage effective values and current effective values at different conduction angles, acquiring apparent power at different conduction angles; and finally, controlling the current effective values, the voltage effective values, the active power and the apparent power to display for user reference. Power parameters can be calibrated according to voltage ratios obtained at different conduction angles, and power parameters can be accurately acquired. Moreover, a user can directly observe real-time power parameters, thereby being convenient for a user to use.

Description

MEASUREMENT METHOD AND MEASUREMENT CIRCUIT FOR POWER

PARAMETER

FIELD

[0001] The present disclosure relates to the field of communication, and particularly to a method and a circuit for measuring a power parameter.

BACKGROUND

[0002] A power meter is an important component of the current intelligent grid, which not only is an important reference for electric power dispatching of a grid company, but also intuitively provides electricity consumption to a user, so as to help the user to form a habit of saving electricity, thus the power meter has great significance. The power meter is generally installed at an overall incoming line terminal of each homer user, to meter electrical energy consumption of all electricity consumption devices inside of the home, and to be served as a credential for charging an electricity bill. For the electrical energy consumption of each of household applications, a device having a metering function is provided to display the electrical energy consumption of each of the household applications in a real-time manner.

[0003] Currently, a power parameter is measured based on a three-wire system, that is, there are three wire connecting terminals on an electricity meter, which are a live-line terminal, a load terminal and a zero-line terminal respectively. In order for acquiring the power parameter, an accurate current sampling value and an accurate voltage sampling value must be acquired, which requires to measure an accurate voltage waveform and an accurate current waveform respectively, to accurately calculate the power parameter.

[0004] With the rise of the concept of intelligent home, it starts to research various electrical intelligent devices based on two-wire power supply, for example, a two-wire electrical switch or a two-wire dimmer. In a control device of a wiring system for home lighting, the two-wire dimmer or the two-wire switch is generally arranged at the live-line terminal, only the live line and the load line are located in a chamber, and the chamber does not include the zero line. The collecting method based on the three-wire system in the conventional technology can not collect a voltage difference between a live-line terminal and a zero-line terminal of the two-wire circuit due to no zero-line terminal in the two-wire circuit, and can not acquire an accurate voltage waveform in actual application, and therefore can not acquire an accurate power parameter.

SUMMARY

[0005] A method and a circuit for measuring a power parameter are provided in the embodiments of the present disclosure, to accurately acquire the power parameter for user convenience.

[0006] A first aspect of the present disclosure provides a method for measuring a power parameter, which includes: acquiring a maximum voltage waveform value at a live-line terminal or a load terminal for each conduction angle of the different conduction angles by adjusting a magnitude of the conduction angle; dividing, for each conduction angle of the different conduction angles, the maximum voltage waveform value by a standard maximum waveform value for the corresponding conduction angle, to obtain a voltage ratio for each conduction angle of the different conduction angles, where the standard maximum waveform value is a peak value of a voltage waveform measured at a standard voltage; acquiring a current effective value for each conduction angle of the different conduction angles; acquiring a voltage effective value and an active power for each conduction angle of the different conduction angles based on the voltage ratio, and acquiring an apparent power for each conduction angle of the different conduction angles based on the voltage effective value and the current effective value for the corresponding conduction angle; and controlling a display of the current effective value, the voltage effective value, the active power and the apparent power.

[0007] Optionally, the acquiring the current effective value for each conduction angle of the different conduction angles includes acquiring the current effective value by a sampling resistor.

[0008] Optionally, before the dividing , for each conduction angle of the different conduction angles, the maximum voltage waveform value by the standard maximum waveform value for the corresponding conduction angle, the method further includes: acquiring a standard maximum waveform value for each conduction angle of the different conduction angles.

[0009] Optionally, acquiring the standard maximum waveform value for each conduction angle of the different conduction angles includes: acquiring a maximum voltage value at the live-line terminal or the load terminal for each conduction angle of the different conduction angles by adjusting a magnitude of the conduction angle; obtaining a voltage maximum value curve based on the maximum voltage value acquired for each conduction angle of the different conduction angles, where a horizontal coordinate of the voltage maximum value curve is each conduction angle, and a longitudinal coordinate of the voltage maximum value curve is a maximum voltage value of a corresponding conduction angle; and acquiring the standard maximum waveform value for each conduction angle of the different conduction angles based on the voltage maximum value curve.

[0010] Optionally, acquiring the voltage effective value for each conduction angle of the different conduction angles based on the voltage ratio includes: multiplying the voltage ratio for each conduction angle of the different conduction angles with the standard voltage for a corresponding conduction angle, to obtain the voltage effective value for each conduction angle of the different conduction angles.

[0011] Optionally, acquiring the voltage effective value for each conduction angle of the different conduction angles based on the voltage ratio includes: integrating, for each conduction angle of the different conduction angles, the square of a transient voltage within a period at the standard voltage, and dividing the integrated value by the number of voltage sampling points within the period to obtain an average value, taking a square root of the average value, and calibrating the average value with the voltage ratio for the corresponding conduction angle, to obtain the voltage effective value for each conduction angle of the different conduction angles.

[0012] Optionally, in a case that a circuit for measuring a power parameter does not include inductive load, acquiring the active power for each conduction angle of the different conduction angles based on the voltage ratio includes: integrating, for each conduction angle of the different conduction angles, a transient power within a period at the standard voltage, and dividing the integrated value by the number of voltage sampling points within the period to obtain an average value, and calibrating the average value with the voltage ratio for the corresponding conduction angle, to obtain the active power for each conduction angle of the different conduction angles.

[0013] Optionally, in a case that a circuit for measuring a power parameter includes inductive load, acquiring the active power for each conduction angle of the different conduction angles based on the voltage ratio includes: collecting, for each conduction angle of the different conduction angles, a voltage waveform at the live-line terminal or the load line terminal within a period; acquiring a phase P corresponding to a target voltage frequency F for each conduction angle of the different conduction angles; acquiring a zero-crossing phase shift for each conduction angle of the different conduction angles, where the phase shift Ps is:

where Fs is a sampling frequency; and after delaying the voltage waveform for Ps, multiplying, in a point-to-point manner, the voltage waveform with a current waveform, integrating the product, and calibrating the integrated value with the voltage ratio for a corresponding conduction angle, to obtain the active power for each conduction angle of the different conduction angles.

[0014] Optionally, the phase P corresponding to the target voltage frequency F may be acquired based on the voltage frequency F by using the Goertzel algorithm.

[0015] A second aspect of the present disclosure provides a circuit for measuring a power parameter, which includes: a live-line terminal, a load terminal, a micro control unit and a display module; where a terminal of the micro control unit is connected to the live-line terminal, and another terminal of the micro control unit is connected to the load terminal; the micro control unit is configured to: acquire a maximum voltage waveform value at the load terminal or the live-line terminal for each conduction angle of different conduction angles; acquire a standard maximum waveform value for each conduction angle of the different conduction angles at a standard voltage; acquire a current waveform for each conduction angle of the different conduction angles, to acquire a current effective value; acquire a voltage effective value and an active power for each conduction angle of the different conduction angles based on the voltage ratio; acquire apparent power for each conduction angle of the different conduction angles based on the voltage effective value and the current effective value for a corresponding conduction angle; and control the display module to display the current effective value, the voltage effective value, the active power and the apparent power; and the display module is configured to display the current effective value, the voltage effective value, the active power and the apparent power.

[0016] Optionally, the circuit for measuring the power parameter may further include: a first field-effect transistor and a second field-effect transistor which are configured to control current in the circuit for measuring the power parameter, and a sampling resistor configured to acquire the current waveform, where the micro control unit includes a processing unit, a first collecting port and a second collecting port; the first field-effect transistor is located between the live-line terminal and the sampling resistor, and the second field-effect transistor is located between the sampling resistor and the load terminal; the first collecting port of the micro control unit is connected to the live-line terminal, and the second collecting port of the micro control unit is connected to a terminal of the sampling resistor, another terminal of the sampling resistor is connected to the load terminal and is earthed; or the first collecting port of the micro control unit is connected to the load terminal, and the second collecting port of the micro control unit is connected to the terminal of the sampling resistor, and the another terminal of the sampling resistor is connected to the load terminal and is earthed; the first collecting port of the micro control unit is configured to: acquire the maximum voltage waveform value of the load terminal or the live-line terminal for each conduction angle of the different conduction angles by adjusting a magnitude of the conduction angle; and acquire the standard maximum waveform value for each conduction angel of the different conduction angles at a standard voltage; the second collecting port of the micro control unit is configured to acquire the current waveform for each conduction angle of the different conduction angles based on the current waveform acquired at the sampling resistor, to acquire the current effective value; the processing unit is configured to: divide, for each conduction angle of the different conduction angles, the maximum voltage waveform value by the standard maximum waveform value for a corresponding conduction angle, to obtain a voltage ratio for each conduction angle of the different conduction angles; acquire the voltage effective value and the active power for each conduction angle of the different conduction angles based on the voltage ratio, and acquire the apparent power based on the current effective value and the voltage effective value.

[0017] Optionally, the circuit for measuring the power parameter may further include a divider resistor, where the divider resistor is located between the first collecting port and the live-line terminal in a case that the first collecting port of the micro control unit is connected to the live-line terminal, or the divider resistor is located between the first collecting port and the load terminal in a case that the first collecting port of the micro control unit is connected to the load terminal.

[0018] Optionally, the micro control unit includes a first micro control unit and a second micro control unit, where the first micro control unit is configured to acquire a power parameter and transmit the power parameter to the second micro control unit via an analog I2C communication, and the second micro control unit is configured to control the display module to display the power parameter.

[0019] It can be seen from the technical solution described above that the embodiments of the present disclosure have the following advantages.

[0020] In the present disclosure, the magnitude of the conduction angle can be adjusted, the maximum voltage waveform value of the live-line terminal or the load terminal for each conduction angel of the different conduction angles is acquired, the maximum voltage waveform value for each conduction angle of the different conduction angles is divided by the standard maximum waveform value, for a corresponding conduction angle, acquired at the standard voltage, to obtain the voltage ratio for each conduction angel of the different conduction angles, the voltage effective value and the active power for each conduction angel of the different conduction angles are acquired based on the voltage ratio, and the apparent power for each conduction angle of the different conduction angles is acquired based on the voltage effective value and the current effective value for the corresponding conduction angle, and the current effective value, the voltage effective value, the active power and the apparent power are controlled to be displayed for user’s reference. In the present disclosure, the power parameter is calibrated based on the voltage ratio acquired for each conduction angle of the different conduction angles, to obtain an accurate two-wire power parameter, and the user can intuitively observe the real-time power parameter for user convenience.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solution in the embodiments of the present disclosure, in the following, drawings required in the description of the embodiments will be introduced simply. Obviously, the drawings in the following description are some embodiments of the disclosure. For those skilled in the art, other drawings can also be obtained according to the drawings without any creative work [0022] Figure 1 is a flow diagram of a method for measuring a power parameter according to an embodiment of the present disclosure; [0023] Figure 2a is a voltage waveform diagram of a live-line terminal in a case that a conduction angle is 0 according to an embodiment of the present disclosure; [0024] Figure 2b is a voltage waveform diagram of a load terminal in a case that a conduction angle is 0 according to an embodiment of the present disclosure; [0025] Figure 3a is a voltage waveform diagram of a live-line terminal in a case that a conduction angle is 3ms according to an embodiment of the present disclosure; [0026] Figure 3b is a voltage waveform diagram of a load terminal in a case that a conduction angle is 3ms according to an embodiment of the present disclosure; [0027] Figure 4a is a voltage waveform diagram of a live-line terminal in a case that a conduction angle is 7ms according to an embodiment of the present disclosure; [0028] Figure 4b is a voltage waveform diagram of a load terminal in a case that a conduction angle is 7ms according to an embodiment of the present disclosure; [0029] Figure 5 is a flow diagram of a method for acquiring a maximum voltage waveform value according to an embodiment of the present disclosure; [0030] Figure 6 is a flow diagram of a method for acquiring a voltage waveform according to an embodiment of the present disclosure; [0031] Figure 7 is a circuit diagram of a circuit for measuring a power parameter according to an embodiment of the present disclosure; [0032] Figure 8 is voltage scanning curves in a case that a voltage effective value is changed from 195 V to 265V according to an embodiment of the present disclosure; [0033] Figure 9 is normalization curves obtained by dividing each of the voltage scanning curves in Figure 8 by a scanning curve of 220V; [0034] Figure 10 is a curve diagram for characterizing dispersion of a voltage value at each of conduction angles in Figure 9; [0035] Figure 11 is a zero-crossing waveform diagram of an energy saving lamp; [0036] Figure 12 is a zero-crossing waveform diagram of a halogen lamp; [0037] Figure 13 is a schematic diagram of a zero-crossing phase shift obtained by the G algorithm according to an embodiment of the present disclosure; [0038] Figure 14 is a schematic diagram of a range of a voltage value after the phase shift is acquired according to an embodiment of the present disclosure; [0039] Figure 15 is a schematic structural diagram of a circuit for measuring a power parameter according to an embodiment of the present disclosure; [0040] Figure 16 is another schematic structural diagram of a circuit for measuring a power parameter according to an embodiment of the present disclosure; and [0041] Figure 17 is another schematic structural diagram of a circuit for measuring a power parameter according to an embodiment of the present disclosure.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0042] Hereinafter, the technical solution in the embodiments of the present disclosure will be described clearly and completely in conjunction with the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, but not all the embodiments. All the other embodiments obtained by those skilled in the art based on the embodiments of the present disclosure without exercise of any inventive skill will fall within the scope of protection of the present disclosure.

[0043] The embodiments of the present disclosure provide a method for measuring a power parameter. The embodiments of the present disclosure further provide a circuit for measuring a power parameter. The method and the circuit for measuring a power parameter are described below with reference to Figure 1 to Figure 17.

First embodiment [0044] The embodiment of the present disclosure provides a method for measuring a power parameter, which is described from the perspective of a circuit for measuring the power parameter for ease of description.

[0045] The method for measuring the power parameter includes: acquiring a maximum voltage waveform value at a live-line terminal or a load terminal for each conduction angle of different conduction angles by adjusting a magnitude of an conduction angle; dividing, for each conduction angle of the different conduction angles, the maximum voltage waveform value by a standard maximum waveform value for a corresponding conduction angle, to obtain a voltage ratio for each conduction angle for the different conduction angles, the standard maximum waveform value is a peak value of a voltage waveform measured at a standard voltage; acquiring a voltage effective value and an active power for each conduction angle of the different conduction angles based on the voltage ratio; acquiring a current effective value for each conduction angle of the different conduction angles; and acquiring an apparent power for each conduction angle of the different conduction angles based on the voltage effective value and the current effective value for a corresponding conduction angle; and controlling the current effective value, the voltage effective value, the active power and the apparent power to be displayed.

[0046] It should be understood that, for a two-wire circuit such as a two-wire electronic switch or a dimmer, a cavity includes a live-line and a load line, and a zero line is not included, a three-wire collection method in the conventional technology is unable to collect a voltage difference between a live-line terminal and a zero-line terminal, and to acquire an accurate voltage waveform.

[0047] In the embodiment, in an operating state, the magnitude of the conduction angle can be adjusted, the maximum voltage waveform value of the live-line terminal or the load terminal can be acquired directly, the voltage ratio for each conduction angle of different conduction angles can be obtained based on the standard maximum waveform value acquired at the standard voltage, and the power parameter is calibrated based on the voltage ratio, to obtain an accurate power parameter, therefore, a technical issue in the conventional technology that the accurate voltage can not be collected to acquire the power parameter is solved, and the user can intuitively acquire the power parameter at any time for user convenience.

[0048] In the embodiment, the current effective value may also be acquired by a sampling resistor directly, and the current effective value is displayed.

[0049] Specifically, in the embodiment, the current effective value acquired above is multiplied with the voltage effective value acquired above, to obtain the apparent power.

[0050] Specifically, in the embodiment, the voltage ratio acquired above is multiplied with the standard voltage, to obtain the voltage effective value.

[0051] Specifically, in the embodiment, for each conduction angle of the different conduction angles, the square of a transient voltage at the standard voltage is integrated within a period, and the integrated value is divided by the number of voltage sampling points within the period, to obtain an average value, then the average value is taken the square root, and the square root is calibrated with the voltage ratio for a corresponding conduction angle, to obtain the voltage effective value.

[0052] Specifically, in a case that the circuit for measuring the power parameter according to the embodiment does not include inductive load, for each conduction angle of the different conduction angles, a transient power at the standard voltage is integrated within a period, and the integrated value is divided by the number of voltage sampling point within the period, to obtain an average value, and then the average value is calibrated with the voltage ratio for a corresponding conduction angle, to obtain the active power for each conduction angle of the different conduction angles.

[0053] In a case that the circuit for measuring the power parameter includes an inductive load, a voltage waveform at the live-line terminal or the load terminal within a period can be collected for each conduction angle of the different conduction angles, a phase P corresponding to a target voltage frequency F for each conduction angle of the different conduction angles is acquired, a zero-crossing phase shift Ps for each conduction angle of the different conduction angles is acquired, and after the voltage waveform is delayed for Ps, the voltage waveform is multiplied with a current waveform in a point-to-point manner, and the product is integrated, then the integrated value is calibrated with the voltage ratio for a corresponding conduction angle, to acquire the active power for each conduction angle of the different conduction angles.

[0054] Specifically, the standard maximum waveform value for each conduction angle of the different conduction angles can be measured in advance, and the standard maximum waveform value of the live-line terminal or the load terminal at the standard voltage can be acquired for each conduction angle of the different conduction angles by the following ways.

[0055] First, the magnitude of the conduction angle is adjusted from large to small at the standard voltage, and the maximum voltage value at the live-line terminal or the load terminal for each conduction angle for the different conduction angles is acquired, a voltage maximum value curve is obtained by the maximum voltage value acquired for each conduction angle of the different conduction angles, a horizontal coordinate of the voltage maximum value curve is each conduction angle, and a longitudinal coordinate of the voltage maximum value curve is a maximum voltage value of a corresponding conduction angle, the standard maximum waveform value for each conduction angle of the different conduction angles are acquired based on the voltage maximum value curve.

[0056] It can be known from the foregoing that, in the present disclosure, the magnitude of the conduction angle can be adjusted first, the maximum voltage waveform value at the live-line terminal or the load terminal for each conduction angle of the different conduction angles is acquired, the maximum voltage waveform value for each conduction angle of the different conduction angles is divided by the standard maximum waveform value, for a corresponding conduction angle, acquired at the standard voltage, to obtain the voltage ratio for each conduction angle of the different conduction angles, the voltage effective value and the active power for each conduction angle of the different conduction angles are acquired based on the voltage ratio, and the apparent power for each conduction angle of the different conduction angles is acquired based on the voltage effective value and the current effective value for a corresponding conduction angle, and the current effective value, the voltage effective value, the active power and the apparent power are controlled to be displayed for user’s reference. In the present disclosure, the power parameter is calibrated based on the voltage ratio acquired for a corresponding conduction angle, to accurately obtain the power parameter of the two-wire system, and the user can intuitively observe the real-time power parameter for user convenience.

Second embodiment [0057] The technical solution of the embodiment of the present disclosure is described in detail below by a specific application example.

[0058] With reference to Figure 1, a specific flow may include 101 to 106.

[0059] In 101, a standard maximum waveform value Vref for each conduction angle of the different conduction angles is acquired at a standard voltage.

[0060] The standard maximum waveform value is a peak value of a voltage waveform acquired at a standard voltage, may be a peak value of the waveform within a period. Specifically, a standard maximum waveform value Vref at a live-line terminal or a zero-line terminal for each conduction angle of the different conduction angles is acquired, the embodiment is described in detail by taking a case that the standard maximum waveform value at the live-line terminal is acquired as an example.

[0061] A value of the standard voltage may be a voltage value such as 220V or 110V, for example, a standard voltage of the commercial power is generally 220V in domestic use, which is not limited in the embodiment.

[0062] For example, the magnitude of the conduction angle is adjusted at the standard voltage of 220V, a peak value Vref of a waveform at the live-line terminal for each conduction angel of the different conduction angles is acquired, for example, the magnitude of the conduction angle may be adjusted from large to small, which includes 1011 to 1013.

[0063] In 1011, the magnitude of the conduction angle is adjusted from large to small at the standard voltage, and a maximum voltage value at the live-line terminal for each conduction angel of the different conduction angles are acquired.

[0064] It should be understood that, at the standard voltage of 220V, a conduction angle of half waveform is in a range from 0ms to 10ms. For example, in order to acquire more accurate waveform, the conduction angle is selected to be in a range from 1.5ms to 8.5ms in the embodiment, the conduction angle may be decreased from 8.5ms to 1.5ms gradually, and the maximum voltage value at the live-line terminal are scanned, to obtain the maximum voltage value for each conduction angel of the different conduction angles.

[0065] It should be illustrated that a maximum voltage value at the load terminal for each conduction angle of the different conduction angles may also be acquired, which is not limited.

[0066] In 1012, a voltage maximum value curve is obtained based on the maximum voltage value for each conduction angle of the different conduction angles acquired in step 1011.

[0067] Different maximum voltage values may be acquired for each conduction angle of the different conduction angles in step 1011, the maximum voltage values are stored into an array subsequently, and therefore the voltage maximum value curve is obtained, a horizontal coordinate of the voltage maximum value curve is each conduction angle, and a longitudinal coordinate of the voltage maximum value curve is a maximum voltage value of a corresponding conduction angle. Alternatively, the longitudinal coordinate of the voltage maximum value curve is each conduction angle, and the horizontal coordinate of voltage maximum value curve is a maximum voltage value of a corresponding conduction angle, which is not limited in the embodiment.

[0068] In 1013, the standard maximum waveform value Vref for each conduction angle of the different conduction angle are acquired based on the voltage maximum value curve obtained in step 1012.

[0069] The standard maximum waveform value Vref corresponding to each conduction angle of the different conduction angles can be acquired intuitively from the voltage maximum value curve.

[0070] Specifically, a method for acquiring a maximum voltage waveform value may also refer to Figure 5, which is a flow diagram of a method for acquiring the standard maximum waveform value Vref when the live-line terminal is scanned. First, a load is turned on, and the magnitude of the conduction angle is adjusted from large to small at the standard voltage, and it is determined whether a current conduction angle is greater than a minimum conduction angle, a standard maximum voltage waveform value for the current conduction angle is acquired and stored in a case that the current conduction angle is greater than the minimum conduction angle, or a window is slid to filter and then store in a case that the current conduction angle is not greater than the minimum conduction angle.

[0071] In 102, the magnitude of the conduction angle is adjusted, and a maximum voltage waveform value Vmax at the live-line terminal for each conduction angle of the different conduction angles is acquired.

[0072] It should be understood that frequency stability and the voltage stability of a grid are two important indexes for measuring quality of a power supply system, the frequency stability of the grid in China is in a range of +0.2HZ, an accumulative error of frequency fluctuation of the grid is small, and is relatively stable. In the embodiment, it is assumed that a target voltage frequency is fixed to be 50Hz, and is a standard sine wave, to detect a change in an voltage amplitude in the grid.

[0073] By taking a case that the conduction angle is 0ms, 3ms and 7ms as an example, a voltage waveform of the live-line terminal, i.e. Live terminal, or the load terminal, i.e. Load terminal, is acquired. With reference to Figure 2a to Figure 4b, Figure 2a is a voltage waveform diagram at the Live terminal in a case that the conduction angle is 0, Figure 2b is a voltage waveform diagram at the Load terminal in a case that the conduction angle is 0, Figure 3a is a voltage waveform diagram at the Live terminal in a case that the conduction angle is 3ms, Figure 3b is a voltage waveform diagram at the Load terminal in a case that the conduction angle is 3ms, Figure 4a is a voltage waveform diagram at the Live terminal in a case that the conduction angle is 7ms, and Figure 4b is a voltage waveform diagram at the Load terminal in a case that the conduction angle is 7ms. It can be known from Figure 2a to Figure 4b that, the voltage waveform of the Live terminal is the same as the voltage waveform of the Load terminal, and the voltage waveform of the Live terminal has a phase difference of 180 degrees from the voltage waveform of the Load terminal, therefore, the Live terminal or the Load terminal may be selected as a reference signal for detecting the voltage amplitude. For ease of description, the embodiment is described in detail by taking the Live terminal as an example.

[0074] For example, the magnitude of the conduction angle may be adjusted in an operating state, and a voltage waveform within a period is selected, to acquire Vmax at the live-line terminal for each conduction angle of the different conduction angles. For example, the user can adjust a dimmer switch to control brightness of the load, and acquire Vmax at the live-line terminal for each brightness of the different brightnesses.

[0075] Specifically, an order of executing step 101 and step 102 is not limited.

[0076] In 103, a voltage ratio Ratio for each conduction angle of the different conduction angles is acquired, where Ratio= Vmax /Vref.

[0077] The voltage ratio is obtained by dividing the maximum voltage waveform value Vmax acquired in step 102 by the standard maximum waveform value Vref measured in step 101;

where Ratio is the voltage ratio.

[0078] Specifically, a method for acquiring the voltage ratio may also refer to Figure 6, which is a flow diagram of a method for acquiring the voltage ratio. First, it is determined whether a filed-efFect transistor is switched off. In a case that the field-effect transistor is switched off, the maximum voltage waveform value Vmax for each conduction angle of the different conduction angles is acquired, and the Vmax is divided by the standard maximum voltage waveform value Vref acquired at the standard voltage, to obtain the Ratio. Or in a case that the field-effect transistor is not switched off, it is determined whether a current conduction angle is smaller a preset conduction angle (for example, it is determined whether the current conduction angle is smaller than 7ms). In a case that the current conduction angle is smaller than 7ms, the voltage waveform value is collected N times (for example, the voltage waveform value is collected five times), and a maximum voltage waveform value acquired each time is stored into an array, and the five voltage waveform values in the array are averaged, to obtain an average value Vavg, and the Vavg is divided by the standard maximum voltage waveform value Vref obtained at the standard voltage, to obtain the Ratio, and the Ratio is recorded.

[0079] In 104, a current effective value for each conduction angle of the different conduction angles is acquired.

[0080] The current effective value Inns is acquired by a sampling resistor, it should be understood that, it can be known from the circuit for measuring the power parameter that the sampling resistor is provided in a primary loop, a waveform obtained at the sampling resistor can reflect current in the primary loop with no distortion, therefore, an accurate current effective value Irms can be acquired directly by coefficient correction.

[0081] The step 104 may also be executed before step 102, which is not limited.

[0082] In 105, a voltage effective value and an active power for each conduction angle of the different conduction angles are acquired based on the voltage ratio Ratio, and an apparent power for each conduction angle for the different conduction angles is acquired based on the voltage effective value and the current effective value for a corresponding conduction angle.

[0083] Specifically, a method for calculating the voltage effective value is described below.

[0084] The voltage effective value is obtained by multiplying the voltage ratio for each conduction angle of the different conduction angles with the standard voltage for a corresponding conduction angle. For example, in a case that the standard voltage in the embodiment may be 220V, the voltage effective value Urms is:

[0085] Also, for each conduction angle of the different conduction angles, the square of a transient voltage at the standard voltage is integrated within a period, and the integrated value is divided by the number of voltage sampling points within the period to obtain an average value, and the average value is taken a square root, and the square root is calibrated with the voltage ratio for a corresponding conduction angle, to obtain the voltage effective value for each conduction angle of the different conduction angles, which can refer to the following formula:

where Kv is a correction coefficient for the voltage effective value, and Kv includes the voltage ratio, Vpn(n) is a transient voltage value at a time instant n, and Sample Count is the number of voltage sampling points within a period.

[0086] It should be illustrated that Vpn(n) in the embodiment is the transient voltage value at the time instant n at the standard voltage, a waveform of the standard voltage can be stored in advance for subsequent calculation. Specifically, the voltage signal has a fixed frequency and is a standard sine wave, a value of a sampling point of the voltage waveform, i.e. a transient voltage value at the standard voltage, may be calculated in advance based on a set sampling time, and is stored in the array. For example, the sampling time in the embodiment is set to be 89 ps, and the transient voltage value v(n) is:

[0087] Specifically, the circuit for measuring the power parameter in the embodiment may refer to Figure 7, which is a schematic diagram of a circuit for measuring a power parameter according to the embodiment. The circuit diagram is described in detail in the embodiment below, which is not described repeatedly.

[0088] Specifically, in order to obtain an accurate power parameter, linearity verification may be performed on the voltage effective value obtained above.

[0089] The embodiment is described in detail by taking a candescent lamp (PHLIPS, 60W) and an energy saving lamp (PHLIPS, Dimmable, 25W) as an example, and the candescent lamp and the energy saving lamp are connected into a dimmer circuit and are supplied by alternating current.

[0090] First, voltage scanning firmware is written into a micro controller unit (MCU, MicroControllerUnit) of the dimmer, to obtain a scanning curve at different voltages by adjusting the voltage effective value. Specifically, the voltage effective value is changed from 195V to 265V, and is changed by 5V each time. With reference to Figure 8 which is graph illustrating voltage scanning curves obtained when the voltage effective value is changed from 195 V to 265V. Specifically, finishing ends of the curves from top to down correspond to voltage scanning curves obtained at the voltage effective valuesl95V, 200V, 205V, ... 260V, 265V subsequently.

[0091] It can be known from Figure 8 that the voltage scanning curves for each conduction angle of the different voltages have regularity. The curve for 220V is severed as a reference curve, and the curve for other voltages is divided by the curve for 220V in a point-to-point manner, to obtain a coefficient curve. For each curve, an average value of latter ten points is serves as a reference value for normalization. With reference to Figure 9, which is a normalization curve obtained by dividing each of the voltage scanning curves in Figure 8 by the scanning curve for 220V, specifically, starting ends of the curves from top to down correspond to normalization curves obtained by dividing the voltage scanning curves obtained at the voltage effective values 195V, 200V, 205V, ... 260V, 265V by the scanning curve for 220V subsequently.

[0092] It can be obtained from Figure 9 that, coefficient fluctuation is small when the conduction angle changes from 6.94ms (8.5ms-26ps*30*2) to 1.5ms (8.5ms-26ps *135*2), dispersion (variance) of the voltage value at each conduction angle can be characterized, with reference to Figure 10, which is a curve diagram for characterizing the dispersion of the voltage value at each conduction angle in Figure 9.

[0093] It can be known from Figure 10 that the dispersion is small, basically 0, for the conduction angle in a range from 6.94ms to the 1.5ms. However, as the conduction angle gets larger, the dispersion gets higher, which represents that the algorithm can calculate the voltage coefficient in a real-time manner and ensure the accuracy of the voltage coefficient in a case that the conduction angle is adjusted between 6.94ms and 1.5ms.

[0094] The apparent power Papp for each conduction angel of the different conduction angles can be calculated based on the voltage effective values UrmS and the current effective values Irms for a corresponding conduction angle described above, specifically, the apparent power is a product of the current effective value and the voltage effective value, which refers to the following formula:

[0095] It should be illustrated that the apparent power may be calculated once per 2S.

[0096] A method for acquiring the active power Pact in the embodiment aims at two cases, i.e. a case that the circuit for measuring the power parameter includes inductive load and a case that the circuit for measuring the power parameter does not include the inductive load, the method for acquiring the active power are different for the two cases. For example, load having strong capacitivity such as an energy saving lamp and load having strong inductivity such as a halogen lamp are measured respectively, to obtain zero-crossing waveforms for the two load described above. With reference to Figure 11 and Figure 12, Figure 11 is a zero crossing waveform of the energy saving lamp, and Figure 12 is a zero crossing waveform of the halogen lamp. Specifically, in Figure 11, a curve 1 is the zero crossing waveform, and the curve 2 is a normal voltage waveform. In Figure 12, a curve 1 is the zero crossing waveform, and the curve 2 is a normal voltage waveform.

[0097] It can be known from Figure 11 and Figure 12 that, the zero crossing waveform for the capacitive load can truly reflect zero crossing of the voltage, and zero crossing delay may occur for the inductive load since that the current lags behind the voltage. Since that the current sampling is triggered by the zero crossing, the number of the zero crossing delay is calculated when the active power is calculated, which is illustrated in detail.

[0098] In a first case that the circuit for measuring a power parameter does not include the inductive load, for each conduction angle of the different conduction angles, a transient power at the standard voltage is integrated within a period, and the integrated value is divided by the number of voltage sampling points within the period, to obtain an average value, and then the average value is calibrated with the voltage ratio for a corresponding conduction angle, to obtain active power for each conduction angle of the different conduction angles, which refers to a formula described below:

where Sample Count is the number of voltage sampling points within a period; v (n) is a transient voltage value at the standard voltage; i (n) is a transient current value at the standard voltage;

Kp is a power correction coefficient, and Kp includes the voltage ratio.

[0099] It should be illustrated that, it is assumed in the embodiment that the voltage signal has a fixed frequency and is a standard sine waveform, a value of a sampling point of the voltage waveform, i.e. a transient voltage value at the standard voltage, may be calculated in advance based on the set sampling time, and is stored into an array, for example, the sampling time in the embodiment may be set to be 89 ps, the transient voltage value v(n) is: v(n) = 774 * sia(2 * it * f * t%f = SO Hz, t = 89us * a) [00100] In a second case that the circuit for measuring the power parameter includes inductive load, it can be known from above that the zero crossing waveform of the capacitive load can truly reflect the zero crossing of the voltage, and the zero crossing delay may occur for the inductive load since that the current lags behind the voltage due to an inductive reactance, therefore, the number of zero crossing delay is calculated when the active power is calculated, to acquire a more accurate active power.

[00101] In the case that the circuit for measuring the power parameter includes inductive load, steps for acquiring the active power may include SI to S4.

[00102] In SI, a voltage waveform at the live-line terminal or the load terminal within a period for each conduction angle of the different conduction angles is collected.

[00103] Specifically, in order to present the voltage waveform within a period better, a certain range of the conduction angle may be selected.

[00104] It can be known from Figure 2a to Figure 4b that, a peak value can be always detected at the Live terminal in a case that the conduction angle is smaller than 5ms, the detected peak value gets smaller in a case that the conduction angle gets larger. Preferably, the voltage waveform at the Live terminal within a period is collected and stored in a case that the conduction angle is smaller than 5ms.

[00105] In S2, a phase P corresponding to a target voltage frequency F is acquired for each conduction angel of the different conduction angles.

[00106] It should be understood that frequency stability of the grid in China is in a range of + 0.2HZ, an accumulative error of frequency fluctuation of the grid is small, and is relatively stable. In the embodiment, it is assumed that the target voltage frequency is fixed to be 50Hz. In order to acquire the phase P corresponding to the voltage frequency F better, the Goertzel algorithm is used for the Live waveform to calculate the phase P corresponding to the voltage frequency F, which is described below.

[00107] Specifically, before the Goertzel algorithm is run, the size of a block N is determined first, the magnitude of the block N determines a frequency resolution. A high N is selected as possible in order for acquiring the greatest frequency resolution, however, the greater the N, the longer the time spent on detecting each target frequency, a suitable value of N is selected based on a calculating speed of an embedded system, so that the target frequency is located at mid-point range of a frequency resolution region. It should be illustrated that it is not necessary that N in the embodiment is integral power of 2.

[00108] Steps of the Goertzel algorithm is described below.

[00109] Coefficients are initialized first: K = N *target_freq/sample_rate; w -2* *k/N; cosine = cos(w);

Sine = sin(w);

Coeff ~ 2 * cosine [00110] Three variants qO, ql and q2 are required for each iteration, and the three variants are initialized to be zero first, the iteration is performed according to three equations below: qO = coeff*ql - q2 + sample; q2 = ql; ql = q© [00111] The target frequency can be detected after the iteration is performed N times:

Real ™ (ql - q2 * cosine) I mag = (q2 * si ne)

Magnitude - sqrt(realA2+imgA2)

Phase = atan2(real/imag) [00112] Specifically, reference is made to Figure 13 which is a phase shift diagram of zero-crossing obtained after using the G algorithm, the embodiment is described in detail by taking a case that the conduction angle is 2ms as an example. In Figure 13, curve 2 is a waveform of the live-line terminal, and curve 1 is a harmonic wave of the target voltage frequency, it can be known from region 3 in Figure 13 that the 32 sampling points occur phase shift.

[00113] Compared with the conventional technology in which the phase P corresponding to the voltage frequency F is obtained by Fast Fourier Transformation, one or multiple frequency components are detected in the embodiment, therefore, the Goertzel algorithm are more effective, and required CPU resources is much less, and a computing speed is high, and for all embedded system having no continuous real-time FFT processing ability, digital signal processing can be realized during a sampling interval by using the Goertzel algorithm.

[00114] In S3, a zero crossing phase shift Ps for each conduction angel of the different conduction angles is acquired. The phase shift is:

where Fs is a sampling frequency.

[00115] In S4, the active power Pact is acquired.

[00116] After the voltage waveform is delayed for Ps, the voltage waveform is multiplied with the current waveform in a point-to-point manner, and the product is integrated, and the integrated value is calibrated with the voltage ratio for the corresponding conduction angle, to obtain the active power Pact for each conduction angel of the different conduction angles.

[00117] It should be illustrated that the recognition for the inductive load may be used in conjunction with the recognition for the lamp load, the number of the zero crossing phase shift points is calculated by calling the algorithm in a case that the inductive load is detected, a voltage after the phase shift, i.e. a voltage in an interval of [N, Fs/F+N], is used when calculating the active power, the voltage after the phase shift is multiplied with the current waveform in a point-to-point manner, and then the product is integrated, and the integrated value is calibrated with the voltage ratio for a corresponding conduction angle, to obtain the active power Pact for each conduction angle of the different conduction angles.

[00118] Specifically, in a case that the circuit for measuring the power parameter includes the inductive load, the method for acquiring the voltage ratio may also refer to Figure 14, which is a flow diagram of a method for acquiring a range of a voltage value after the phase shift in a case that there is the inductive load. First, in a case that it is detected that the load is the inductive load, a voltage curve is scanned at a selected small conduction angle, a voltage waveform of the live-line terminal within a period is collected at the selected conduction angle, and a phase P at a target frequency F is acquired, the G algorithm is used for the voltage waveform collected above to acquire a phase shift Ps for each conduction angel of the different conduction angles, a range value [PS, Fs/F+PS]of the voltage is acquired.

[00119] In 106, the current effective value, the voltage effective value, the active power and the apparent power are controlled to be displayed.

[00120] The current effective value is obtained in step 104, and the voltage effective value, the active power and the apparent power are obtained in step 105, the power parameters described above can be displayed in a real-time manner for user’s reference. In the embodiment, the power parameters are intuitively displayed to user, for user’s reference at any time and for the user convenience.

[00121] Specifically, a power factor can be obtained by the active power and the apparent power acquired above, the power factor is a product of the active power and the apparent power. Therefore, the power factor is controlled to be displayed.

[00122] It should be illustrated that the embodiment is not limited to be applied into a two-wire device, and to be also applied into a three-wire device.

[00123] It can be known from the foregoing that, in the present disclosure, the magnitude of the conduction angle can be adjusted, the maximum voltage waveform value at the live-line terminal or the load terminal for each conduction angel of the different conduction angles is acquired, the maximum voltage waveform value for each conduction angle of the different conduction angles is divided by the standard maximum waveform value, for a corresponding conduction angle, acquired at the standard voltage, to obtain the voltage ratio for each conduction angel of the different conduction angles, the voltage effective value and the active power for each conduction angel of the different conduction angles are acquired based on the voltage ratio, and the apparent power for each conduction angel of the different conduction angles is acquired based on the voltage effective value and the current effective value for a corresponding conduction angle, and the current effective value, the voltage effective value, the active power and the apparent power are controlled to be displayed for user’s reference. In the present disclosure, the power parameter is calibrated based on the voltage ratio acquired for each conduction angel of the different conduction angles, to accurately obtain the power parameter of the two-wire circuit, and the user can intuitively observe the real-time power parameter for user convenience.

Third embodiment [00124] In order to implement the solution described above better, the embodiments further provide a circuit for measuring a power parameter, which includes a live-line terminal, a load terminal, a micro control unit 200 and a display module 300, with reference to Figure 15, which is a schematic diagram of the circuit for measuring the power parameter in the embodiment.

[00125] The micro control unit may include a live-line terminal, a load terminal, a micro control unit 200 and a display module 300.

[00126] A terminal of the micro control unit 200 is connected to the live-line terminal, and another terminal of the micro control unit 200 is connected to the load terminal.

[00127] The micro control unit 200 is configured to: acquire a maximum voltage waveform value at the load terminal or the live-line terminal for each conduction angel of different conduction angles by adjusting a magnitude of the conduction angle; acquire a standard maximum waveform value for each conduction angel of the different conduction angles at a standard voltage; acquire a current waveform for each conduction angel of the different conduction angles to obtain a current effective value; acquire a voltage effective value and an active power for each conduction angle of the different conduction angles based on a voltage ratio; acquire an apparent power for the different conduction angles based on the voltage effective value and the current effective value for a corresponding conduction angle; and control the display module 300 to display the current effective value, the voltage effective value, the active power and the apparent power.

[00128] The display module 300 is configured to display the current effective value, the voltage effective value, the active power and the apparent power.

[00129] Specifically, the circuit for measuring the power parameter in the embodiment may further include: a sampling resistor 300 configured to acquire a current waveform, and a first field-effect transistor 501 and a second field-effect transistor 502 which are configured to control current in the circuit for measuring the power parameter, with referent to Figure 7 or Figure 16 and Figure 17, Figure 7 is a circuit diagram of a circuit for measuring a power parameter, Figure 16 and Figure 17 are another schematic diagram of the circuit for measuring the power parameter, specifically, Figure 16 is a schematic diagram in a case that a first collecting port is connected to the live-line terminal, and Figure 17 is a schematic diagram in a case that the first collecting port is connected to the load terminal.

[00130] The micro control unit 200 may include a first collecting port 201, a second collecting port 202 and a processing unit 203. Specifically, the first collecting port 201 is connected to the live-line terminal, or is connected to the load terminal.

[00131] Specifically, in a case that the first collecting port 201 is connected to the live-line terminal, the second collecting port 202 is connected to a terminal of the sampling resistor 400, and another terminal of the sampling resistor 400 is connected to the load terminal and is earthed.

[00132] Specifically, in a case that the first collecting port 201 is connected to the load terminal, the second collecting port 202 is connected to the terminal of the sampling resistor 400, and the another terminal of the sampling resistor 400 is connected to the load terminal and is earthed.

[00133] The first field-effect resistor 501 is located between the live-line terminal and the sampling resistor 400, the second field-effect resistor 502 is located between the sampling resistor 400 and the load terminal, the first filed-effect transistor 501 and the second field-effect transistor 502 are configured to control the current.

[00134] The first collecting port 201 of the micro control unit 200 is configured to: acquire a maximum voltage waveform value at the load terminal or the live-line terminal for each conduction angel of different conduction angles by adjusting a magnitude of the conduction angle; and acquire a standard maximum waveform value for each conduction angel of the different conduction angles at a standard voltage. The second collecting port 202 of the micro control unit 200 is configured to acquire a current waveform for each conduction angel of the different conduction angles to obtain a current effective value. The processing unit 203 is configured to: divide, for each conduction angel of the different conduction angles, the maximum voltage waveform value obtained above by the standard maximum waveform value for a corresponding conduction angle to obtain a voltage ratio for each conduction angle of the different conduction angles; acquire a voltage effective value and an active power for each conduction angle of the different conduction angles based on the voltage ratio; acquire apparent power based on the voltage effective value and the current effective value; and control the display module 300 to display the current effective value, the voltage effective value, the active power and the apparent power.

[00135] The display module 300 is configured to display a power parameter, and the power parameter includes the voltage effective value, the current effective value, the active power, the apparent power and a power factor. It should be understood that the power parameter may be calculated based on the active power and the apparent power.

[00136] Specifically, the display module 300 may be a liquid crystal display (LCD, Liquid Crystal Display).

[00137] In order to obtain a more accurate voltage waveform, the embodiment further includes a divider resistor. In a case that the first collecting port 201 of the micro control unit 200 is connected to the live-line terminal, a divider resistor is provided between the first collecting port 201 and the live-line terminal. And in a case that the first collecting port 201 of the micro control unit 200 is connected to the load terminal, a divider resistor is provided between the first collecting port 201 and the load terminal.

[00138] Specifically, a circuit diagram of the circuit for measuring the power parameter may refer to Figure 7 which is a circuit diagram of the circuit for measuring the power parameter according to the embodiment. Specifically, the micro control unit MCU may include a master MCU and a slave MCU. For ease of description, the master MCU is described as a first MCU, and the slave MCU is described as a second MCU.

[00139] Specifically, the first MCU is configured to acquire the power parameter, and transmit the power parameter to the second MCU via an analog I2C communication, and the second MCU is configured to control the display module to display the power parameter. The sampling resistor may include a sampling resistor R1 and a sampling resistor R2. The divider resistor may include a divider resistor R3 and a divider resistor R4. The divider resistor may include a divider resistor R3 and a divider resistor R4. The embodiment includes two field-effect transistors Q1 and Q2. For ease of description, the first field-effect transistor is described as Ql, and Q1 is located between the live-line terminal and the sampling resistor, and the second field-effect transistor is described as Q2, and Q2 is located between the sampling resistor and the load terminal, Ql and Q2 are configured to control the current.

[00140] It can be known from Figure 7 that, the first MCU is the master MCU, which can acquire the maximum voltage waveform value Vmax for each conduction angel of the different conduction angles from the Live terminal, and acquire a voltage ratio at a certain conduction angle based on the maximum voltage waveform value Vmax and a standard maximum waveform value acquired at a standard voltage, acquire an accurate power parameter based on the voltage ratio, and acquire an accurate current effective value based on a current of a primary loop acquired from the sampling resistor R1 and R2. The second MCU is the slave MCU, the first MCU transmits the power parameter to the second MCU via the analog I2C communication, and the second MCU controls the LCD to display the acquired power parameter. Specifically, the power parameter in the embodiment includes the voltage effective value, the current effective value, the active power, the apparent power and the power factor.

[00141] Specifically, the sampling resistor Rf and the sampling resistor R2 are located between the second collecting port AD2 of the MCU and Q2. Specifically, waveforms obtained at the sampling resistor Rf and the sampling resistor R2 in the primary loop represent sampling, at the Rf and R2, for current in a positive direction and a negative direction of the circuit for measuring the power parameter, respectively, and can reflect a current in the primary loop with no distortion, thereby acquiring an accurate current effective value.

[00142] In order to obtain an accurate voltage waveform, the divider resistor R3 and the divider resistor R4 are provided in the embodiment. Specifically, in a case that the first collecting port ADI of the MCU is connected to the live-line terminal, the divider resistor R3 and the divider resistor R4 are provided between the first collecting port ADf and the live-line terminal correspondingly. Alternatively, in a case that the first collecting port ADf of the micro control unit is connected to the load terminal, the divider resistor R3 and the divider resistor R4 are provided between the first collecting port ADI and the load terminal correspondingly.

[00143] It can be known from Figure 7 that, in the embodiment, a terminal of a dimmer is connected to the live-line terminal, and another terminal of the dimmer is connected to the load terminal, and there is no zero line terminal. In the embodiment, the power parameter can be calibrated based on the voltage ratio acquired at different conduction angles, to acquire an accurate power parameter, and the user can intuitively acquire the power parameter at any time for user convenience.

[00144] The circuit for measuring the power parameter in the embodiment of the present disclosure includes the micro control unit, the first field-effect transistor and the second field-effect transistor which are configured to control the current, the sampling resistor and the display module configured to display the power parameter. The first collecting port of the micro control unit is configured to: acquire the maximum voltage waveform value at the load terminal or the live-line terminal for each conduction angel of the different conduction angles by adjusting a magnitude of the conduction angle; and acquire the standard maximum waveform value at different conduction angles at a standard voltage. The second collecting port of the micro control unit is configured to acquire the current waveform for each conduction angle for the different conduction angles to obtain the current effective value. The processing unit of the micro control unit is configured to: divide the maximum voltage waveform value for each conduction angle of the different conduction angles obtained above by the standard maximum waveform value for a corresponding conduction angle to obtain the voltage ratio for each conduction angle of the different conduction angles; acquire the voltage effective value and the active power for each conduction angle of the different conduction angles based on the voltage ratio; acquire the apparent power based on the voltage effective value and the current effective value. In the present disclosure, the power parameter can be calibrated based on the voltage ratio acquired for each conduction angle of the different conduction angles and therefore the power parameter of a two-wire circuit can be acquired accurately, and the user can intuitively observe a real-time power parameter for user convenience.

[00145] Those skilled in the art should understand that all of or a part of steps for realizing the above method embodiments may be performed by instructing related hardware through a program. The program may be stored in a computer readable storage medium. The proceeding storage medium includes a Read Only Memory, a magnetic disc or an optic disc.

[00146] The method and the circuit for measuring the power parameter according to the present disclosure are described in detail above, the principle and the embodiments of the present disclosure are described by specific examples, and the embodiments above are only intended to assist in understanding the method and the core concept of the present disclosure; for those skilled in the art, changes can be made to the embodiments and the application scope based on the concept of the embodiments of the present disclosure, as above, the specification is not understood to limit the present disclosure.

Claims (13)

1. A method for measuring a power parameter, comprising: acquiring a maximum voltage waveform value at a live-line terminal or a load terminal for each conduction angle of different conduction angles by adjusting a magnitude of the conduction angle; dividing, for each conduction angle of the different conduction angles, the maximum voltage waveform value by a standard maximum waveform value for a corresponding conduction angle, to obtain a voltage ratio for each conduction angle of the different conduction angles, wherein the standard maximum waveform value is a peak value of a voltage waveform measured at a standard voltage; acquiring a current effective value for each conduction angle of the different conduction angles; acquiring a voltage effective value and an active power for each conduction angle of the different conduction angles based on the voltage ratio, and acquiring an apparent power for each conduction angle of the different conduction angles based on the voltage effective value and the current effective value for a corresponding conduction angle; and controlling a display of the current effective value, the voltage effective value, the active power and the apparent power.

2. The method for measuring a power parameter according to claim 1, wherein the acquiring the current effective value for each conduction angle of the different conduction angles comprises acquiring the current effective value by a sampling resistor.

3. The method for measuring a power parameter according to claim 1, wherein before the step of dividing, for each conduction angle of the different conduction angles, the maximum voltage waveform value by the standard maximum waveform value for a corresponding conduction angle, the method further comprises: acquiring a standard maximum waveform value for each conduction angle of the different conduction angles.

4. The method for measuring a power parameter according to claim 3, wherein the acquiring the standard maximum waveform value for each conduction angle of the different conduction angles comprises: acquiring a maximum voltage value at the live-line terminal or the load terminal for each conduction angle of the different conduction angles at a standard voltage by adjusting a magnitude of the conduction angle from large to small; obtaining a voltage maximum value curve based on the maximum voltage value acquired for each conduction angle of the different conduction angles, wherein a horizontal coordinate of the voltage maximum value curve is each conduction angle, and a longitudinal coordinate of the voltage maximum value curve is a maximum voltage value of a corresponding conduction angle; and acquiring the standard maximum waveform value for each conduction angle of the different conduction angles based on the voltage maximum value curve.

5. The method for measuring a power parameter according to any one of claims 1 to 4, wherein the acquiring the voltage effective value for each conduction angle of the different conduction angles based on the voltage ratio comprises: multiplying the voltage ratio for each conduction angle of the different conduction angles with the standard voltage for a corresponding conduction angle, to obtain the voltage effective value for each conduction angle of the different conduction angles.

6. The method for measuring a power parameter according to any one of claims 1 to 4, wherein the acquiring the voltage effective value for each conduction angle of the different conduction angles based on the voltage ratio comprises: integrating, for each conduction angle of the different conduction angles, the square of a transient voltage within a period at the standard voltage, and dividing the integrated value by the number of voltage sampling points within the period to obtain an average value, taking a square root of the average value, and calibrating the average value with the voltage ratio for the corresponding conduction angle, to obtain the voltage effective value for each conduction angle of the different conduction angles.

7. The method for measuring a power parameter according to any one of claims 1 to 4, wherein in a case that a circuit for measuring a power parameter does not comprise an inductive load, acquiring the active power for each conduction angle of the different conduction angles based on the voltage ratio comprises: integrating, for each conduction angle of the different conduction angles, a transient power within a period at the standard voltage, and dividing the integrated value by the number of voltage sampling points within the period to obtain an average value, and calibrating the average value with the voltage ratio for the corresponding conduction angle, to obtain the active power for each conduction angle of the different conduction angles.

8. The method for measuring a power parameter according to any one of claims 1 to 4, wherein in a case that a circuit for measuring a power parameter comprises an inductive load, acquiring the active power for each conduction angle of the different conduction angles based on the voltage ratio comprises: collecting, for each conduction angle of the different conduction angles, a voltage waveform at the live-line terminal or the load line terminal within a period; acquiring a phase P corresponding to a target voltage frequency F for each conduction angle of the different conduction angles; acquiring a zero-crossing phase shift for each conduction angle of the different conduction angles, wherein the phase shift Ps is:

where Fs is a sampling frequency; and multiplying, in a point-to-point manner, the voltage waveform after delaying the voltage waveform for Ps with a current waveform, integrating the product of the multiplying, and calibrating the integrated value with the voltage ratio for the corresponding conduction angle, to obtain the active power for each conduction angle of the different conduction angles.

9. The method for measuring a power parameter according to claim 8, wherein the phase P corresponding to the target voltage frequency F is acquired based on the voltage frequency F by using the Goertzel algorithm.

10. A circuit for measuring a power parameter, comprising: a live-line terminal, a load terminal, a micro control unit and a display module; wherein a terminal of the micro control unit is connected to the live-line terminal, and another terminal of the micro control unit is connected to the load terminal; the micro control unit is configured to: acquire a maximum voltage waveform value at the load terminal or the live-line terminal for each conduction angel of different conduction angles by adjusting a magnitude of the conduction angle; acquire a standard maximum waveform value for each conduction angle of the different conduction angles at a standard voltage; acquire a current waveform for each conduction angle of the different conduction angles, to acquire a current effective value; acquire a voltage effective value and an active power for each conduction angle of the different conduction angles based on a voltage ratio; acquire an apparent power for each conduction angle of the different conduction angles based on the voltage effective value and the current effective value for the corresponding conduction angle; and control the display module to display the current effective value, the voltage effective value, the active power and the apparent power; and the display module is configured to display the current effective value, the voltage effective value, the active power and the apparent power.

11. The circuit for measuring a power parameter according to claim 10, further comprising a first field-effect transistor and a second field-effect transistor which are configured to control a current in the circuit for measuring the power parameter and a sampling resistor configured to acquire the current waveform, wherein the micro control unit comprises a processing unit, a first collecting port and a second collecting port; the first field-effect transistor is arranged between the live-line terminal and the sampling resistor, and the second field-effect transistor is arranged between the sampling resistor and the load terminal; the first collecting port of the micro control unit is connected to the live-line terminal, and the second collecting port of the micro control unit is connected to a terminal of the sampling resistor, another terminal of the sampling resistor is connected to the load terminal and is earthed; or the first collecting port of the micro control unit is connected to the load terminal, and the second collecting port of the micro control unit is connected to the terminal of the sampling resistor, and the another terminal of the sampling resistor is connected to the load terminal and is earthed; the first collecting port of the micro control unit is configured to: acquire the maximum voltage waveform value at the load terminal or the live-line terminal for each conduction angle of the different conduction angles by adjusting a magnitude of the conductive angle; and acquire the standard maximum waveform value for each conduction angle of the different conduction angles at a standard voltage; the second collecting port of the micro control unit is configured to acquire the current waveform for each conduction angle of the different conduction angles based on the current waveform acquired at the sampling resistor, to acquire the current effective value; the processing unit is configured to: divide the maximum voltage waveform value for each conduction angle of the different conduction angles by the standard maximum waveform value for the corresponding conduction angle, to obtain a voltage ratio for each conduction angle of the different conduction angles; acquire the voltage effective value and the active power for each conduction angle of the different conduction angles based on the voltage ratio, and acquire the apparent power based on the current effective value and the voltage effective value.

12. The circuit for measuring a power parameter according to claim 10 or 11, further comprising a divider resistor, wherein the divider resistor is arranged between the first collecting port and the live-line terminal in a case that the first collecting port of the micro control unit is connected to the live-line terminal, or the divider resistor is arranged between the first collecting port and the load terminal in a case that the first collecting port of the micro control unit is connected to the load terminal.

13. The circuit for measuring a power parameter according to claim 10 or 11, wherein the micro control unit comprises a first micro control unit and a second micro control unit, the first micro control unit is configured to acquire a power parameter and transmit the power parameter to the second micro control unit via an analog I2C communication, and the second micro control unit is configured to control the display module to display the power parameter.