Phase measurement system and method for low power factor

Abstract

The invention discloses a phase measurement system and method for a low power factor, and belongs to the technical field of phase measurement. The device comprises a phase measurement unit which is used for accessing a three-phase wide-range voltage signal and a current signal of a low-power-factor device, performing gain and amplitude amplification processing on the voltage signal and the current signal, performing phase measurement on the processed voltage signal and current signal, and uploading a phase measurement result to a communication control module; and the communication control module is used for reading the phase measurement result. According to the invention, the phase of the low-power factor can be precisely measured, and the precision is high.

Description

Technical Field

[0001] The present invention relates to the technical field of phase measurement, and more particularly, to a phase measurement system and method for low power factor. Background Art

[0002] Phase measurement technology is an important technology in electronics and physics. It mainly involves the measurement of the phase difference between two or more signals of the same frequency. Phase measurement refers to the measurement of the phase difference between two or more signals of the same frequency. The phase difference is the relative position of two signal waveforms in time, usually expressed in degrees (°) or radians (rad). Phase measurement is of great significance in the field of power metering. It can be used for power grid quality monitoring, calculation of active and reactive power, accurate measurement of electric energy metering and billing, and fairness of electric energy charges. According to the draft for comments of the new JJG 597-202X verification procedure, the power factor requirement is as low as 0.25 above 0.1A current, and 0.5 below 0.1A. The minimum test current is 0.3mA, and the power factor at 0.3mA is 1.0. In extreme cases, the power factor may be lower than 0.01, so it is necessary to be able to accurately measure the voltage and current phase.

[0003] The existing phase measurement system methods are divided into analog methods and digital methods; the analog method generally uses the oscilloscope method and the zero indication (comparison) method; the oscilloscope method is to add the two measured signals to the two Y channels of the dual-trace oscilloscope at the same time, directly compare them, and calculate the phase difference based on the ratio of the time interval of the two waveforms to the waveform period. This method is simple and easy, but the accuracy is low and it is difficult to integrate for automatic test systems; the zero indication (comparison) method uses a variable phase shifter in series with the measured signal, and then adds it to the phase comparator (such as an oscilloscope, indicator, etc.) at the same time as another signal of the same frequency, and adjusts the variable phase shifter so that the comparator indicates a zero-value phase. The reading on the phase shifter is the phase difference between the two signals; the digital method generally uses a direct-reading phase meter, a time interval measurement method, and a voltage measurement method; a direct-reading phase meter, It has the advantages of direct reading of phase difference, fast measurement speed, and the ability to display phase changes; digital direct reading phase meter method and vector voltmeter method are currently the most commonly used methods, and are generally measured through algorithms; based on the time interval measurement method, the phase difference is converted into a time interval, the time interval is first measured and then converted into a phase difference. This method uses an electronic counter to count the counting pulses generated by the time base signal, and the count value is proportional to the phase difference. Since the periodic signal jitters near the zero point, it is difficult to accurately measure the phase time interval. It is generally used in measurement systems with a phase accuracy of about 0.1°; based on the voltage measurement method, the phase difference is converted into a voltage, the voltage is first measured and then converted into a phase difference. This method usually involves the modulation and demodulation process of the signal, and is prone to introduce errors in the modulation and demodulation process, making it difficult to improve the accuracy of the test volume.

[0004] Traditional analog methods, such as voltage measurement methods based on integration circuits and digital counting methods based on microprocessors or timers and counters, may be affected by factors such as leakage current of the integration capacitor, temperature drift, quantization error of the A / D converter, and the introduction of hysteresis comparators, resulting in limited accuracy. Digital signal processing (DSP) methods usually have higher accuracy and stability. The phase measurement system currently used in China is a 0.01-level lightning, EMH and other imported standard electric energy meters. This standard meter is designed for traditional 50Hz / 60Hz industrial frequency measurement, and the nominal phase accuracy is generally 0.01 degrees. Domestic research institutions have designed small current and low power factor standard devices for 0.3mA-0.3A, but the phase test accuracy is limited to 0.3', and the current test range is narrow to 0.3mA-0.3A. According to relevant regulations and specifications, high-precision phase measurement in a wide current range of 0.3mA-120A is required, and the test power factor is as low as 0.25 or 0.1. Therefore, a high-precision and high-stability phase measurement system with a wide current range is urgently needed, which can achieve high-precision and high-stability phase measurement of 0.001 degrees, and then provide technical means and methods for electric energy metering under a wide power factor range of 0.1-1.0.

[0005] The difficulty of the current industrial frequency phase measurement system is that due to the jitter problem of the sine wave at the zero-crossing point, the analog test method and the digital test method based on zero-crossing comparison have large phase jitter errors, that is, the phase signal-to-noise ratio is not enough, and it is difficult to achieve even through various algorithm compensation. Under the condition of limited signal-to-noise ratio itself, it is also difficult to achieve high-precision phase measurement; for low power factor measurement, since the power factor calculation formula of the current measurement system uses the inverse sine or inverse tangent method, there is a nonlinear problem. At partial power factors, a smaller phase jitter will introduce a larger phase error. For example, when the inverse sine test method is used, when the sine value is relatively large such as 90°, the same angle change will result in a larger change in the sine value at 0° and basically no change at 90°, making it difficult to achieve phase measurement at low power factors.

[0006] Currently, existing standard meters or electric energy standard devices generally use high-precision synchronous sampling ADC to directly calculate the amplitude, phase, power and electric energy, such as Figure 1 As shown in the figure, the input three-phase voltage and current signals are sampled by ADC, and generally a high-precision multi-channel ADC of 24 bits or more is used. The three-phase voltage and current signal sampling data is used to calculate the phase difference between the voltage and current through algorithms such as DFT, so as to calculate the power factor value. However, the ADC sampling accuracy is limited, especially when the zero point is crossed, it is difficult to effectively and accurately identify the zero point through the sampled voltage under the influence of phase noise. It can only be processed by various mean filtering algorithms such as the average value algorithm, the quasi-synchronous algorithm, etc., or the active and effective apparent power are calculated by the dot product and the active equals The method of multiplying the cosine product of apparent power and power factor and using the arccosine function to solve the power factor angle has the following problems: First, for low power factors, the active content is small, the resolution of the ADC is limited, and it is difficult to accurately measure the active value, resulting in a large active measurement error, which in turn affects the power factor calculation and measurement; second, the arccosine measurement method has a large nonlinear error at low power factors. A very small power factor change will lead to a large change in the phase angle value; therefore, it is difficult to fundamentally solve the problem of phase measurement accuracy, especially the high-precision phase measurement of 0.001 degrees. Summary of the invention

[0007] In view of the above problems, the present invention proposes a phase measurement system for low power factor, comprising:

[0008] A phase measurement unit is used to access the three-phase wide-range voltage signal and current signal of the low power factor device, perform gain and amplitude amplification processing on the voltage signal and current signal, perform phase measurement on the processed voltage signal and current signal, and upload the phase measurement result to the communication control module;

[0009] The phase measurement unit comprises:

[0010] A V / V conversion module, used for receiving a three-phase wide-range voltage signal, converting the three-phase wide-range voltage signal into a voltage signal in a low-voltage range, and transmitting the voltage signal in the first low-voltage range to a first automatic gain signal conditioning module;

[0011] A first automatic gain signal conditioning module, used for fixing the voltage signal in the first low voltage range to a first fixed voltage signal and inputting it into the phase measurement module;

[0012] An I / V conversion module, used for receiving a three-phase wide-range current signal, converting the three-phase wide-range current signal into a voltage signal in a second low-voltage range, and transmitting the voltage signal in the second low-voltage range to a second automatic gain signal conditioning module;

[0013] A second automatic gain signal conditioning module, used for fixing the voltage signal in the second low voltage range to a second fixed voltage signal and inputting it into the phase measurement module;

[0014] A phase measurement module, used to measure the phases of the first fixed voltage signal and the second fixed voltage signal;

[0015] The communication control module is used to read the phase measurement result.

[0016] Optionally, the phase measurement unit includes: phase measurement units for phase A, phase B and phase C, which are respectively used to access the wide range voltage signals and current signals of phase A, phase B and phase C of the low power factor device.

[0017] Optional, wide range voltage signal voltage range: 30V-456V.

[0018] Optional, wide range current signal voltage range: 0.3mA-120A.

[0019] Optionally, the voltage range of the voltage signal in the first low-voltage range and the voltage signal in the second low-voltage range is: 0.13V-2V.

[0020] Optional, V / V conversion module, including:

[0021] An integrated precision voltage-dividing resistor of at least M ohm level is used to divide a wide range of voltage signals, and the connecting wires of the integrated precision voltage-dividing resistor are connected in a shielded manner.

[0022] Optional, I / V conversion module, including:

[0023] A high-current precision 100A-level shunt is used to shunt a wide range of current signals, and the distributed inductance of the shunt is less than 80nH.

[0024] Optionally, the first automatic gain signal conditioning module and the second automatic gain signal conditioning module both include: a two-stage analog variable gain amplifier;

[0025] The first-stage analog variable gain amplifier is used to amplify the input voltage signal of the first / second low voltage range by a first-stage gain to at least 200mV;

[0026] The second stage analog variable gain amplifier is used to amplify the voltage signal with a gain of at least 200mV and perform a second-stage gain amplification to 2V.

[0027] Optional, phase measurement module, including:

[0028] A low phase noise clock module, used for providing a low phase noise clock signal with the same frequency and phase for the first generator DDS and the second generator DDS, and controlling the clock synchronization of the first generator DDS and the second generator DDS based on the low phase noise clock signal with the same frequency and phase;

[0029] A first generator DDS, configured to output a first analog signal to a first multiplier;

[0030] A second generator DDS, used for outputting a second analog signal to a second multiplier;

[0031] a first multiplier, configured to receive a first fixed voltage signal and the first analog signal, and perform a multiplication operation on the first fixed voltage signal and the first analog signal to generate a first multiplication operation result;

[0032] a second multiplier, configured to receive a second fixed voltage signal and the second analog signal, and perform a multiplication operation on the second fixed voltage signal and the second analog signal to generate a second multiplication operation result;

[0033] A first ADC high-speed sampler is used to sample the first multiplication result and upload the sampled first multiplication result to the processor DSP;

[0034] A second ADC high-speed sampler is used to sample the second multiplication result and upload the sampled second multiplication result to the processor DSP;

[0035] The processor DSP is used to perform calculations on the first multiplication result and the second multiplication result to determine the phases of the three-phase wide-range voltage signal and current signal.

[0036] Optionally, the processor DSP performs operations on the first multiplication operation result and the second multiplication operation result, including:

[0037] Based on the first multiplication result and the second multiplication result, the phase and frequency of the first analog signal and the second analog signal are adjusted respectively to make the first analog signal orthogonal to the first fixed voltage signal and the second analog signal orthogonal to the second fixed voltage signal, and the phase control words of the first generator DDS and the second generator DDS are read according to the orthogonal result, and the phase difference between the first fixed voltage signal and the second voltage signal is calculated based on the phase control word, and the phase of the three-phase wide-range voltage signal and current signal is calculated according to the phase difference.

[0038] On the other hand, the present invention also proposes a phase measurement method for low power factor, comprising:

[0039] Accessing the three-phase wide-range voltage signal and current signal of the low power factor device through the phase measurement unit, performing gain and amplitude amplification processing on the voltage signal and current signal, performing phase measurement on the processed voltage signal and current signal, and uploading the phase measurement result to the communication control module;

[0040] Wherein, a three-phase wide-range voltage signal is connected through a V / V conversion module of a phase measurement unit, the three-phase wide-range voltage signal is converted into a voltage signal in a low-voltage range, and the voltage signal in the first low-voltage range is transmitted to a first automatic gain signal conditioning module;

[0041] Fixing the voltage signal in the first low voltage range as a first fixed voltage signal and inputting it into the phase measurement module through a first automatic gain signal conditioning module of the phase measurement unit;

[0042] Accessing a three-phase wide-range current signal through an I / V conversion module of the phase measurement unit, converting the three-phase wide-range current signal into a voltage signal in a second low-voltage range, and transmitting the voltage signal in the second low-voltage range to a second automatic gain signal conditioning module;

[0043] Fixing the voltage signal in the second low voltage range as a second fixed voltage signal and inputting it into the phase measurement module through a second automatic gain signal conditioning module of the phase measurement unit;

[0044] Measuring the phases of the first fixed voltage signal and the second fixed voltage signal by a phase measurement module of a phase measurement unit;

[0045] The phase measurement result is read through the communication control module.

[0046] Optionally, the phase measurement unit includes: phase measurement units for phase A, phase B and phase C, which are respectively used to access the wide range voltage signals and current signals of phase A, phase B and phase C of the low power factor device.

[0047] Optional, wide range voltage signal voltage range: 30V-456V.

[0048] Optional, wide range current signal voltage range: 0.3mA-120A.

[0049] Optionally, the voltage range of the voltage signal in the first low-voltage range and the voltage signal in the second low-voltage range is: 0.13V-2V.

[0050] Optional, V / V conversion module, including:

[0051] An integrated precision voltage-dividing resistor of at least M ohm level is used to divide a wide range of voltage signals, and the connecting wires of the integrated precision voltage-dividing resistor are connected in a shielded manner.

[0052] Optional, I / V conversion module, including:

[0053] A high-current precision 100A-level shunt is used to shunt a wide range of current signals, and the distributed inductance of the shunt is less than 80nH.

[0054] Optionally, the first automatic gain signal conditioning module and the second automatic gain signal conditioning module both include: a two-stage analog variable gain amplifier;

[0055] The first-stage analog variable gain amplifier is used to amplify the input voltage signal of the first / second low voltage range by a first-stage gain to at least 200mV;

[0056] The second stage analog variable gain amplifier is used to amplify the voltage signal with a gain of at least 200mV and perform a second-stage gain amplification to 2V.

[0057] Optional, phase measurement module, including:

[0058] A low phase noise clock module, used for providing a low phase noise clock signal with the same frequency and phase for the first generator DDS and the second generator DDS, and controlling the clock synchronization of the first generator DDS and the second generator DDS based on the low phase noise clock signal with the same frequency and phase;

[0059] A first generator DDS, configured to output a first analog signal to a first multiplier;

[0060] A second generator DDS, used for outputting a second analog signal to a second multiplier;

[0061] a first multiplier, configured to receive a first fixed voltage signal and the first analog signal, and perform a multiplication operation on the first fixed voltage signal and the first analog signal to generate a first multiplication operation result;

[0062] a second multiplier, configured to receive a second fixed voltage signal and the second analog signal, and perform a multiplication operation on the second fixed voltage signal and the second analog signal to generate a second multiplication operation result;

[0063] A first ADC high-speed sampler is used to sample the first multiplication result and upload the sampled first multiplication result to the processor DSP;

[0064] A second ADC high-speed sampler is used to sample the second multiplication result and upload the sampled second multiplication result to the processor DSP;

[0065] The processor DSP is used to perform calculations on the first multiplication result and the second multiplication result to determine the phases of the three-phase wide-range voltage signal and current signal.

[0066] Optionally, the processor DSP performs operations on the first multiplication operation result and the second multiplication operation result, including:

[0067] Based on the first multiplication result and the second multiplication result, the phase and frequency of the first analog signal and the second analog signal are adjusted respectively to make the first analog signal orthogonal to the first fixed voltage signal and the second analog signal orthogonal to the second fixed voltage signal, and the phase control words of the first generator DDS and the second generator DDS are read according to the orthogonal result, and the phase difference between the first fixed voltage signal and the second voltage signal is calculated based on the phase control word, and the phase of the three-phase wide-range voltage signal and current signal is calculated according to the phase difference.

[0068] In yet another aspect, the present invention further provides a computing device, comprising: one or more processors;

[0069] a processor for executing one or more programs;

[0070] When the one or more programs are executed by the one or more processors, the above-described method is implemented.

[0071] In yet another aspect, the present invention further provides a computer-readable storage medium having a computer program stored thereon, wherein when the computer program is executed, the method described above is implemented.

[0072] Compared with the prior art, the present invention has the following beneficial effects:

[0073] The present invention provides a phase measurement system for low power factor, comprising: a phase measurement unit, which is used to access a three-phase wide-range voltage signal and a current signal of a low power factor device, perform gain and amplitude amplification processing on the voltage signal and the current signal, perform phase measurement on the processed voltage signal and the current signal, and upload the phase measurement result to a communication control module; the phase measurement unit comprises: a V / V conversion module, which is used to access a three-phase wide-range voltage signal, convert the three-phase wide-range voltage signal into a voltage signal in a low voltage range, and transmit the voltage signal in the first low voltage range to a first automatic gain signal conditioning module; the first automatic gain signal conditioning module, Used to fix the voltage signal of the first low-voltage range as a first fixed voltage signal and input it into the phase measurement module; I / V conversion module, used to access the three-phase wide-range current signal, convert the three-phase wide-range current signal into a voltage signal of the second low-voltage range, and transmit the voltage signal of the second low-voltage range to the second automatic gain signal conditioning module; the second automatic gain signal conditioning module, used to fix the voltage signal of the second low-voltage range as a second fixed voltage signal and input it into the phase measurement module; the phase measurement module, used to measure the phase of the first fixed voltage signal and the second fixed voltage signal; the communication control module, used to read the phase measurement result. The present invention can access the ground range signal through the V / V conversion module and the I / V conversion module respectively, and convert the signal, and then fix the converted signal through the first automatic gain signal conditioning module and the second automatic gain signal conditioning module, and measure the fixed signal through the phase measurement module, so that the phase of the low power factor can be accurately measured with high accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0074] Figure 1 It is a phase measurement diagram of an existing electric energy metering device;

[0075] Figure 2 is a structural diagram of the system of the present invention;

[0076] Figure 3 It is a structural diagram of a phase measurement unit of the system of the present invention;

[0077] Figure 4 The structure principle diagram of the phase measurement module of the system of the present invention;

[0078] Figure 5 A circuit block diagram of a low phase noise clock submodule of the system of the present invention;

[0079] Figure 6 It is a structural block diagram of the DSP processor of the system of the present invention;

[0080] Figure 7 It is a principle block diagram of a multiplier of the system of the present invention;

[0081] Figure 8 It is a flow chart of phase feedback calculation of the system of the present invention;

[0082] Fig. 9 It is a structural diagram of a low-latency V / V conversion module of the system of the present invention;

[0083] Fig.10 It is a structural diagram of a low-latency I / V conversion module of the system of the present invention;

[0084] Fig.11 It is a block diagram of the automatic gain signal conditioning module of the system of the present invention;

[0085] Fig.12 The schematic diagram of the circuit principle of a single 60dB automatic gain converter of the system of the present invention is shown in FIG. DETAILED DESCRIPTION

[0086] Now, exemplary embodiments of the present invention are described with reference to the accompanying drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to disclose the present invention in detail and completely and to fully convey the scope of the present invention to those skilled in the art. The terms used in the exemplary embodiments shown in the accompanying drawings are not intended to limit the present invention. In the accompanying drawings, the same units / elements are marked with the same reference numerals.

[0087] Unless otherwise specified, the terms (including technical terms) used herein have the commonly understood meanings to those skilled in the art. In addition, it is understood that the terms defined in commonly used dictionaries should be understood to have the same meanings as those in the context of the relevant fields, and should not be understood as idealized or overly formal meanings.

[0088] Embodiment 1:

[0089] The present invention proposes a phase measurement system for low power factor, such as Figure 2 As shown, including:

[0090] A phase measurement unit is used to access the three-phase wide-range voltage signal and current signal of the low power factor device, perform gain and amplitude amplification processing on the voltage signal and current signal, perform phase measurement on the processed voltage signal and current signal, and upload the phase measurement result to the communication control module;

[0091] The phase measurement unit comprises:

[0092] A V / V conversion module, used for receiving a three-phase wide-range voltage signal, converting the three-phase wide-range voltage signal into a voltage signal in a low-voltage range, and transmitting the voltage signal in the first low-voltage range to a first automatic gain signal conditioning module;

[0093] A first automatic gain signal conditioning module, used for fixing the voltage signal in the first low voltage range to a first fixed voltage signal and inputting it into the phase measurement module;

[0094] An I / V conversion module, used for receiving a three-phase wide-range current signal, converting the three-phase wide-range current signal into a voltage signal in a second low-voltage range, and transmitting the voltage signal in the second low-voltage range to a second automatic gain signal conditioning module;

[0095] A second automatic gain signal conditioning module, used for fixing the voltage signal in the second low voltage range to a second fixed voltage signal and inputting it into the phase measurement module;

[0096] A phase measurement module, used to measure the phases of the first fixed voltage signal and the second fixed voltage signal;

[0097] The communication control module is used to read the phase measurement result.

[0098] The phase measurement unit includes: phase measurement units for phase A, phase B and phase C, which are respectively used to access the wide range voltage signals and current signals of phase A, phase B and phase C of the low power factor device.

[0099] Among them, the voltage range of the wide range voltage signal is: 30V-456V.

[0100] Among them, the voltage range of the wide range current signal is: 0.3mA-120A.

[0101] The voltage range of the voltage signal in the first low voltage range and the voltage signal in the second low voltage range is 0.13V-2V.

[0102] Among them, the V / V conversion module includes:

[0103] An integrated precision voltage-dividing resistor of at least M ohm level is used to divide a wide range of voltage signals, and the connecting wires of the integrated precision voltage-dividing resistor are connected in a shielded manner.

[0104] Among them, the I / V conversion module includes:

[0105] A high-current precision 100A-level shunt is used to shunt a wide range of current signals, and the distributed inductance of the shunt is less than 80nH.

[0106] Wherein, the first automatic gain signal conditioning module and the second automatic gain signal conditioning module both include: a two-stage analog variable gain amplifier;

[0107] The first-stage analog variable gain amplifier is used to amplify the input voltage signal of the first / second low voltage range by a first-stage gain to at least 200mV;

[0108] The second stage analog variable gain amplifier is used to amplify the voltage signal with a gain of at least 200mV and perform a second-stage gain amplification to 2V.

[0109] Wherein, the phase measurement module includes:

[0110] A low phase noise clock module, used for providing a low phase noise clock signal with the same frequency and phase for the first generator DDS and the second generator DDS, and controlling the clock synchronization of the first generator DDS and the second generator DDS based on the low phase noise clock signal with the same frequency and phase;

[0111] A first generator DDS, configured to output a first analog signal to a first multiplier;

[0112] A second generator DDS, used for outputting a second analog signal to a second multiplier;

[0113] a first multiplier, configured to receive a first fixed voltage signal and the first analog signal, and perform a multiplication operation on the first fixed voltage signal and the first analog signal to generate a first multiplication operation result;

[0114] a second multiplier, configured to receive a second fixed voltage signal and the second analog signal, and perform a multiplication operation on the second fixed voltage signal and the second analog signal to generate a second multiplication operation result;

[0115] A first ADC high-speed sampler is used to sample the first multiplication result and upload the sampled first multiplication result to the processor DSP;

[0116] A second ADC high-speed sampler is used to sample the second multiplication result and upload the sampled second multiplication result to the processor DSP;

[0117] The processor DSP is used to perform calculations on the first multiplication result and the second multiplication result to determine the phases of the three-phase wide-range voltage signal and current signal.

[0118] The processor DSP performs operations on the first multiplication operation result and the second multiplication operation result, including:

[0119] Based on the first multiplication result and the second multiplication result, the phase and frequency of the first analog signal and the second analog signal are adjusted respectively to make the first analog signal orthogonal to the first fixed voltage signal and the second analog signal orthogonal to the second fixed voltage signal, and the phase control words of the first generator DDS and the second generator DDS are read according to the orthogonal result, and the phase difference between the first fixed voltage signal and the second voltage signal is calculated based on the phase control word, and the phase of the three-phase wide-range voltage signal and current signal is calculated according to the phase difference.

[0120] The following is a further description of the system of the present invention in combination with the principles of each module:

[0121] The architecture diagram of the present invention is as follows: Figure 2 As shown, it includes A-phase input, B-phase input, C-phase input, A-phase phase measurement, B-phase phase measurement, C-phase phase measurement, and a communication control module. The phase measurement system and method for a low power factor standard device of the present invention, as a part of the low power factor standard device, respectively performs high-precision measurements on the phases of the three-phase voltage and current, has stronger flexibility, breaks through the bit limit of the existing ADC, reduces the phase noise jitter caused by the zero-crossing test method, improves the phase measurement accuracy and stability, and realizes high-precision phase measurement. The phase measurement module can be read by the low power factor standard device through the communication control module, thereby providing accurate phase test for the low power factor standard device.

[0122] Phase measurement unit, such as Figure 3As shown, three identical circuits are used to measure the phases of phase A, phase B, and phase C respectively. Phase A is used for explanation below. The 30V-456V voltage signal with wide input range is converted into a 0.13V-2V voltage signal through a high stability, low latency, and V / V conversion module. The 0-2V voltage signal is fixed to a 2V output voltage signal through an automatic gain signal conditioning module 1. The steepness of the zero crossing point is increased by amplifying the amplitude of the low-end signal, suppressing the zero crossing jitter problem caused by interference noise, and improving the phase noise of the low-end voltage signal. High-precision phase measurement is achieved through the phase measurement module; the 0.3mA-120 A voltage signal, through the high stability, low latency I / V conversion module, the 0.3mA-120A voltage signal is converted into a 0.13V-2V voltage signal, and the 0-2V voltage signal is fixed to a 2V output voltage signal through the automatic gain signal conditioning module 1. By amplifying the low-end signal amplitude, the steepness of the zero crossing point is increased, the zero crossing jitter problem caused by interference noise is suppressed, and the phase noise of the low-end voltage signal is improved. The phase measurement module based on the DDS phase measurement technology of analog-to-digital mixed negative feedback realizes high-precision phase measurement. For the specific phase measurement implementation method, please refer to the phase measurement module; the phase measurement data of phase A, phase B, and phase C can be read through the communication control module;

[0123] 1. Phase measurement module, such as Figure 4As shown; the phase measurement module of the present invention is implemented by DDS phase measurement technology based on analog-digital mixed negative feedback, and high-precision phase measurement is achieved by combining analog circuits and digital measurements. The low phase noise clock module is connected to DDS generator 1 and DDS generator 2 to provide the two DDS generators with low phase noise clock signals of the same frequency and phase, ensuring that the two DDS generators are in a clock synchronization state, so that the phase between voltage and current can be calculated through subsequent algorithms; DDS generator 1 outputs fitting signal 1, which is multiplied by the input voltage signal through multiplier 1, and the result of the operation is sampled by high-speed sampling ADC1. The sampled data is processed and operated by DSP to adjust the signal phase and frequency output by the DDS generator, and finally achieve the effect of orthogonality between the fitting signal 1 and the input voltage signal, that is, the output of the multiplier is directly The current component is close to 0 (see 1.1 Principle and method of DDS phase measurement technology based on analog-to-digital mixed negative feedback for details); DDS generator 2 outputs fitting signal 2, which is multiplied by the input voltage signal through multiplier 1. The result of the operation is sampled by high-speed sampling ADC1, and the sampled data is processed by DSP to adjust the signal phase and frequency output by the DDS generator, and finally achieve the effect of orthogonality between the fitting signal 2 and the input current signal, that is, the DC component of the multiplier output is close to 0; the DSP processor reads the phase control words of DDS generator 1 and DDS generator 2, and measures the phase between voltage and current by calculating the phase difference. At present, for the frequency measurement of pure industrial frequency, the frequency measurement accuracy can be easily reached within 0.0001Hz through long-term zero-crossing average frequency measurement method, quasi-synchronous frequency measurement algorithm and other testing methods, and the phase jitter caused by 0.0001Hz frequency change can be ignored relative to the phase of 0.001 degree, and the frequency control accuracy of the DDS generator can reach one in 4 billion, the frequency error of the DDS output can be ignored, and the frequency deviation of the input signal and the fitting signal can be considered as the frequency measurement deviation. Therefore, the input signal and the fitting signal can completely reach the same frequency, which can fully meet the requirements of the present invention. Because the problem of how to have the same frequency of the fitting signal and the voltage or current input signal belongs to a mature testing method, the present invention will not go into details. As a known condition, the following analysis assumes that the input current or voltage signal and the fitting signal have the same frequency.

[0124] The phase measurement module is implemented based on the principle and method of DDS phase measurement technology with analog-digital mixed negative feedback, including:

[0125] Assume the input voltage signal is a sinusoidal signal:

[0126]

[0127] Assuming the input current signal is a sinusoidal signal:

[0128]

[0129] Assume that DDS generator 1 generates a sinusoidal signal:

[0130]

[0131] Assume that DDS generator 2 generates a sinusoidal signal:

[0132]

[0133] As can be seen from the figure above, the output Uo1 of multiplier 1 is, assuming that the multiplication coefficient of multiplier 1 is k1:

[0134]

[0135] At this time, the signal output by the multiplier includes a DC signal component:

[0136]

[0137] At this time, the signal output by the multiplier includes an AC signal component:

[0138]

[0139] For a sinusoidal periodic signal, the average value is 0, that is, the integral value of the entire period is zero, and the period of the multiplier output signal is

[0140]

[0141]

[0142] Therefore, by integrating the output signal of the multiplier over a whole cycle, a DC component can be obtained:

[0143]

[0144] From the above formula, we can see that the DC component of the multiplier output is The sine value of the phase difference between the voltage and current input signals before the multiplier input is completely linearly related. Therefore, the DC component of the multiplier output can represent the output phase difference value. For example, when the phase difference is 0, that is, at this time

[0145]

[0146] For example, when the phase difference is 90, that is, at this time:

[0147]

[0148] For example, when the phase difference is 0.001 degrees, that is, at this time:

[0149]

[0150] Therefore, the fitting signal value output by the DDS generator can be adjusted by the output value feedback of multiplier 1, and finally the fitting signal output by the DDS generator and the voltage signal can be orthogonal, and a high-precision 90-degree phase difference can be achieved between the fitting signal output by the DDS generator. In the same principle, the fitting signal value output by the DDS generator can be adjusted by the output value feedback of multiplier 2, and finally the fitting signal output by the DDS generator and the current signal can be orthogonal, and a high-precision 90-degree phase difference can be achieved between the fitting signal output by the DDS generator.

[0151] The present invention needs to achieve a phase measurement of 0.001 degrees, and the measurement resolution of the DC value output by the multiplier needs to be at the uV level. Since the present invention is mainly aimed at industrial frequency measurement, the rated frequency of its AC component is 100Hz, which is close to the DC measurement value. If a filter is used to filter out, a filter of order 8 or above needs to be used. At the same time, a large resistance voltage or a large capacity capacitor will be introduced into the circuit, which will cause very large noise and cause inaccurate DC component measurement. Therefore, it is difficult to effectively filter out the noise through an analog filter. The present invention combines the digital sampling method to achieve high-precision DC measurement through digital filtering to avoid introducing other additional noise, and adjusts the phase control word of the DDS generator 1 through feedback from the DSP processor to achieve phase adjustment of the fitting signal 1 output by the DDS generator 1. When the DC measurement value reaches below the set value, it can be considered that the phase difference between the fitting signal 1 output by DDS1 and the voltage signal is 90 degrees; in the same principle, the phase difference between the current signal and the fitting signal 2 output by DDS2 is 90 degrees; at this time, read the DDS signal generator 1 and the phase control word of DDS signal generator 2. At this time, the difference between the two phase control words is the phase difference of the voltage and current signals. The present invention adopts a phase measurement principle based on DDS feedback differential measurement to eliminate the error of DDS itself. The final phase accuracy is determined by the clock signal of DDS and the software setting value. Theoretically, the accuracy is the phase adjustment resolution of DDS. The present invention adopts a DDS chip with 32-bit phase resolution, so the theoretical phase resolution can reach 360 / 2^32=8.38x10-8 degrees. However, it is difficult to reach the theoretical value due to the limitation of the phase noise of the analog circuit and the clock. The present invention is based on the DDS phase measurement technology principle of analog-to-digital mixed negative feedback. It does not directly use the DC value output by the multiplier to calculate the phase difference method, but further reduces the phase noise through the analog circuit. The dual DDS feedback differential measurement method is adopted. Based on the sine and cosine orthogonal multiplication principle, combined with the dual DDS feedback differential measurement phase measurement principle, high-precision phase measurement is achieved, and the phase measurement accuracy can reach 0.001 degrees.

[0152] Low phase noise clock modules such as Figure 5 As shown, the Butler oscillator circuit implemented in a discrete manner is a low-cost alternative clock source with phase noise performance that is relatively better than typical clock oscillators. It is powered by a single power supply (+5V) and integrates a TTL output stage with an output clock frequency of 125MHz, achieving a good balance between low phase noise performance, circuit complexity and cost. The reference oscillator phase noise and the residual phase noise of the AD9835 together constitute the total phase noise of the DDS output signal. The residual phase noise of the AD9835 under the conditions of 1kHz offset, 5MHz carrier and 125MHz reference clock is –134dBc, which fully meets the requirements of the design of the present invention.

[0153] DSP processors, such as Figure 6 As shown, the dual-core DSP processor BF531 of ADI Company is selected, and 128M DDR is expanded, 52KB on-chip L1 memory can be configured as 32KB L1 instruction memory SRAM / cache, 16KBBL1 data memory SRAM / cache, 4KB L1 scratch pad SRAM, parallel peripheral interface, support ITU-R 656 video data format, two dual-channel full-duplex synchronous serial ports, support eight stereo I2S channels, 12 DMA channels, support one-dimensional and two-dimensional data transmission, memory controller, provide seamless connection with multiple groups of external SDRAM, SRAM, flash memory or ROM, 3 timers / counters, support PWM, pulse width and event counting mode, UART, compatible with SPI port, adopt event processor mode, support real-time clock, built-in watchdog timer, with 1 to 63 times frequency multiplication capability of phase-locked loop, strong data processing performance, with large RAM space, convenient data calculation and processing, meet the requirements of the present invention.

[0154] The DDS signal generator uses ADI's direct digital frequency synthesizer (DDS) AD9835, which uses advanced technology and has a built-in high-speed, high-performance DAC to form a complete digital programmable, high-frequency synthesizer. It integrates a phase accumulator, a COS lookup table, and a 10-bit digital-to-analog converter in a single CMOS chip, providing two modulation capabilities: phase modulation and frequency modulation. It supports a maximum clock rate of 50MHz, and the frequency control accuracy can reach 1 in 4 billion. It has a 32-bit phase accumulator and a phase modulation resolution of 8.38x10-8 degrees, which can meet the requirements of the invention. Modulation is loaded into registers through a serial interface to achieve phase and frequency adjustment control, which can facilitate the control and reading of the DSP processor.

[0155] Multiplier such as Figure 7As shown, AD835 is selected. AD835 is a complete four-quadrant voltage output analog multiplier, manufactured using advanced dielectric isolation complementary bipolar process. It generates a linear product of X and Y voltage inputs, with a -3dB output bandwidth of 250MHz (small signal rise time of 1ns), a full-scale (-1V to +1V) rise and fall time of 2.5ns (using 150Ω standard RL), and a 0.1% settling time of typically 20ns. It uses a ±5V power supply during normal operation. Its differential multiplication input (X, Y) and summation input (Z) are in a high-impedance state, and the low-impedance output voltage (W) can reach up to ±2.5V, and can drive a load as low as 25Ω. AD835 has outstanding speed performance and very low product noise. After the offset voltage is calibrated, the influence on the measured DC component can be ignored, and high-precision phase multiplication calculation can be achieved.

[0156] The present invention needs to achieve a phase measurement of 0.001 degrees, and the measurement resolution of the DC value output by the multiplier needs to be at the uV level. Since the present invention is mainly aimed at power frequency measurement, the AC component frequency is 100Hz, which is similar to the measurement value of DC. If a filter is used to filter, a filter of 8 or more orders is required. At the same time, a voltage with a large resistance value or a capacitor with a large capacity will be introduced into the circuit, which will cause very large noise. Therefore, it is difficult to effectively filter it by means of an analog filter. The present invention processes the DC and AC signals output by the multiplier through a high-speed ADC sampling and a digital algorithm to achieve high-precision DC measurement. For the AD converter of DC sampling, its DC resolution needs to reach 1uV. The input range of a general ADC is 5V, so the effective conversion bit number (ENOB) of the high-precision ADC is required to be not less than 22Bit. However, the effective conversion bit number of AD is often limited by the signal-to-noise ratio (SNR), and various errors are introduced in the data processing conversion process. The AD converter here is preferably 24Bit.

[0157] The following is the actual implementation plan:

[0158] The high-precision A / D converter in the present invention adopts the AD7190 converter of ADI. AD7190 is a low-noise complete analog front end suitable for high-precision measurement applications. It integrates a low-noise, 24-bit Σ-Δ analog-to-digital converter (ADC). The on-chip low-noise gain stage means that small signals can be directly input. This device can be configured as two differential inputs or four pseudo-differential inputs. The on-chip channel sequencer can enable multiple channels, and the AD7190 performs conversions on each enabled channel in sequence, which can simplify communication with the device. The on-chip 4.92MHz clock can be used as the clock source of the ADC; alternatively, an external clock or crystal oscillator can also be used. The output data rate of the device can vary from 4.7Hz to 4.8kHz. This device provides two digital filter options. The choice of the filter affects the root mean square noise and noise-free resolution, settling time, and 50Hz / 60Hz rejection when working at the programmed output data rate. For applications that require all conversions to be established, the AD7190 has a zero-delay feature that enables fast measurements.

[0159] like Figure 8 As shown in FIG. 1 , it is a flow chart of phase measurement calculation. First, the DSP processor reads the sampling value of the high-speed ADC1, accurately calculates the DC component value therein, and determines whether the DC value reaches the set phase value. The program converts the set phase measurement accuracy into the DC set value through calculation. If the set value is not reached, the DSP controls the DDS to adjust the output phase control word and adjust the phase output of the DDS to form a closed-loop feedback adjustment process until the DC value reaches the set phase value. Similarly, the DSP processor reads the sampling value of the high-speed ADC1, accurately calculates the DC component value therein, and determines whether the DC value reaches the set phase value. The program converts the set phase measurement accuracy into the DC set value through calculation. If the set value is not reached, the DSP controls the DDS to adjust the output phase control word. The phase control word output is used to adjust the phase output of DDS, forming a closed-loop feedback adjustment process until the DC value reaches the set phase value; when the DC measurement values ​​of high-speed ADC1 and high-speed ADC2 reach the set values, the phase control word of the DDS signal generator for voltage phase measurement and the phase control word of the DDS signal generator for current phase measurement are read respectively, and the phase measurement value is calculated through the phase control word values ​​of voltage and current and the system clock; assuming that the phase control word value of the DDS signal generator for voltage phase measurement is φD1, the phase control word value of the DDS signal generator for voltage phase measurement is φD2, the clock frequency of the DDS signal generator is FDDS, and the phase control word is 32 bits, the measured phase difference φUI is:

[0160]

[0161] V / V conversion module, such as Fig. 9As shown, the resistor voltage division is to convert the input high voltage into the low voltage to be sampled by connecting the high-end bridge arm resistor and the low-end bridge arm resistor in series. In the figure, Vout=Vin*R2 / (R1+R2). The highest voltage that needs to be measured by the present invention is 30V-456V. The input voltage of the general multiplier is 0-5V, and the power supply operating range of the general operational amplifier is ±15V. Therefore, it is necessary to divide the large input voltage to facilitate the multiplication of the post-stage multiplier and the fitting signal to achieve phase measurement. For the high-voltage measurement of 456V, considering the heating of the resistor and the test accuracy, it is necessary to use a high-precision large-resistance voltage division resistor, at least M ohm level. The resistor has a small resistance value, a large power on the resistor, and a large heat generation, which leads to a large temperature change of the resistor, resulting in a large temperature offset and aging drift of the resistor, which is not conducive to high-precision measurement. The resistor has a large resistance value, and forms a filtering effect with the distributed parameters in the circuit, affecting the phase measurement. Therefore, such a wide range of high stability and low-latency voltage V / V conversion is difficult to achieve accurate measurement using an ordinary voltage division circuit.

[0162] The present invention adopts an integrated precision voltage-dividing resistor, and the connecting wire adopts a shielded connection. Since the back stage has an automatic gain conversion circuit, the processing method here is different from the conventional wide-range voltage input for range switching and switching different voltage-dividing resistors for different voltage segments. The voltage dividing ratio is fixed here, so an integrated precision voltage-dividing resistor can be used, and the manufacturer can be required to compensate for the frequency response of the voltage-dividing resistor to ensure low phase delay during voltage division processing. At the same time, the signal transmission line adopts shielded wires, equipotential and other methods to reduce the phase error problem caused by distributed capacitance under high impedance of voltage input, thereby meeting the design requirements of the present invention.

[0163] V / I conversion module, such as Fig.10 As shown, the present invention needs to ensure the low delay characteristic of the phase. The general high-precision sampling methods such as mutual inductors and zero-flux sensors have limited bandwidths. Generally, the phase difference of a 0.01-level mutual inductor is 0.6′, which is difficult to meet the phase delay requirement of 0.001 degrees of the present invention. Since the present invention has no special requirements for amplitude accuracy, the shunt solution realizes the low-delay, high-stability, and wide-range I / V conversion requirements. The present invention adopts Vishay's high-current and high-precision 100A shunt for current I / V conversion. Its distributed inductance is less than 80nH, and the impact on phase delay can be ignored.

[0164] Fig.10 The resistance of R precision resistor, the output current of the transformer is I, and the voltage on both sides of the precision resistor is VOUT:

[0165] UOUT=I*R

[0166] Automatic gain signal conditioning modules, such as Fig.11 As shown, a two-stage 60dB analog variable gain amplifier is used, such as Fig.12 As shown, the input signal is connected to a 60dB analog variable gain amplifier, the input signal is amplified by a second-stage 60dB analog variable gain amplifier 1, and the amplified signal is further amplified by a second-stage 60dB analog variable gain amplifier 2. The amplification factor is automatically controlled by an automatic gain controller. The first-stage gain control is to amplify the output to 200mV, and the second-stage gain control is to amplify the output to 2V, ensuring that the output voltage is 2V; the reason why a two-stage analog variable gain amplifier is used here is that the current amplification needs to be from 0.3mA-120A, so the maximum gain span is 120A / 0.3mA=400000 times, so a two-stage 60dB analog variable amplifier is used, and its amplification factor range is 1-1000000 times, which meets the requirements.

[0167] The analog variable gain amplifier uses ADI's AD8336 with an adjustable gain factor of 1 to 1000 times. It is a low-noise, single-ended, linear-in-dB, general-purpose variable gain amplifier that can operate over a large power supply voltage range. It has a built-in non-dedicated preamplifier with a usable gain range of 6dB to 26dB. The VGA gain range is 0dB to 60dB, and the absolute gain limit is -26dB to +34dB. When the preamplifier gain is adjusted to 12dB, the combined 3dB bandwidth of the preamplifier and VGA is 100MHz, and the amplifier is fully usable within 80MHz. When using a ±5V power supply, the maximum output swing is 7V peak-to-peak, using The architecture maintains good frequency response over the entire gain range of the VGA, and the fully independent voltage feedback preamplifier supports both inverting and non-inverting gain topologies. It has a built-in offset correction function and is suitable for high-precision amplification applications. It also has a built-in automatic gain controller, which only requires simple peripheral devices, output amplitude and control speed settings. It also has a slew rate of 550V / us, and can achieve delay-free gain conversion of less than 2nS, meeting the requirements of the present invention. For the automatic gain conditioning module 1 with voltage signal input, theoretically only one stage of amplification is required. A two-stage 60dB analog variable gain amplifier is also used here. One is to match the current signal conditioning loop to further reduce the delay effect. The other is to reduce the voltage output of each stage through two-stage amplification, thereby further reducing the phase delay effect caused by the slew rate.

[0168] At present, the phase measurement system used in China is a 0.01-level lightning, EMH and other imported standard electric energy meters. This standard meter is designed for traditional 50Hz / 60Hz industrial frequency measurement, and the nominal phase accuracy is generally 0.01 degrees. Domestic research institutions have designed small current and low power factor standard devices for 0.3mA-0.3A, but the phase test accuracy is limited to 0.3', and the current test range is narrow to 0.3mA-0.3A. According to relevant regulations and specifications, high-precision phase measurement in a wide current range of 0.3mA-120A is required, and the test power factor is as low as 0.25 or 0.1. Therefore, a high-precision and high-stability phase measurement system with a wide current range is urgently needed, which can achieve high-precision and high-stability phase measurement of 0.001 degrees, and then provide technical means and methods for electric energy metering under a wide power factor range of 0.1-1.0.

[0169] The difficulty of the current power frequency phase measurement system is that due to the jitter problem of the sine wave at the zero crossing point, the analog test method and digital test method based on zero crossing comparison have a large phase jitter error, that is, the phase signal-to-noise ratio is not enough, and it is difficult to achieve even through various algorithm compensation. Under the condition of limited signal-to-noise ratio, it is also difficult to achieve high-precision phase measurement; for low power factor measurement, since the power factor calculation formula of the current measurement system uses the inverse sine or inverse tangent method, there is a nonlinear problem. At partial power factors, a small phase jitter will introduce a large phase error. For example, when the inverse sine test method is used, when the sine value is relatively large such as 90°, the same angle change will be positive at 0°. The chord value changes greatly and basically does not change at 90°, making it difficult to achieve phase measurement under low power factor. The present invention adopts a deep analog-digital combination method, taking into account the high precision and stability of digital signal processing testing, reducing phase noise through analog circuits, improving the phase signal-to-noise ratio, and further improving the high precision and stability of phase testing using digital signal processing through a dual DDS feedback differential measurement method with ultra-high phase resolution, breaking through the limit of phase test accuracy of traditional digital signal processing methods, and combining high-stability, low-latency V / V conversion and I / V conversion technology and high-speed AWG automatic gain amplification technology to achieve high-precision, high-stability voltage and current phase precision measurement over a wide current range.

[0170] Embodiment 2:

[0171] The present invention also proposes a phase measurement method for low power factor, comprising:

[0172] Accessing the three-phase wide-range voltage signal and current signal of the low power factor device through the phase measurement unit, performing gain and amplitude amplification processing on the voltage signal and current signal, performing phase measurement on the processed voltage signal and current signal, and uploading the phase measurement result to the communication control module;

[0173] Wherein, a three-phase wide-range voltage signal is connected through a V / V conversion module of a phase measurement unit, the three-phase wide-range voltage signal is converted into a voltage signal in a low-voltage range, and the voltage signal in the first low-voltage range is transmitted to a first automatic gain signal conditioning module;

[0174] Fixing the voltage signal in the first low voltage range as a first fixed voltage signal and inputting it into the phase measurement module through a first automatic gain signal conditioning module of the phase measurement unit;

[0175] Accessing a three-phase wide-range current signal through an I / V conversion module of the phase measurement unit, converting the three-phase wide-range current signal into a voltage signal in a second low-voltage range, and transmitting the voltage signal in the second low-voltage range to a second automatic gain signal conditioning module;

[0176] Fixing the voltage signal in the second low voltage range as a second fixed voltage signal and inputting it into the phase measurement module through a second automatic gain signal conditioning module of the phase measurement unit;

[0177] Measuring the phases of the first fixed voltage signal and the second fixed voltage signal by a phase measurement module of a phase measurement unit;

[0178] The phase measurement result is read through the communication control module.

[0179] The phase measurement unit includes: phase measurement units for phase A, phase B and phase C, which are respectively used to access the wide range voltage signals and current signals of phase A, phase B and phase C of the low power factor device.

[0180] Among them, the voltage range of the wide range voltage signal is: 30V-456V.

[0181] Among them, the voltage range of the wide range current signal is: 0.3mA-120A.

[0182] The voltage range of the voltage signal in the first low voltage range and the voltage signal in the second low voltage range is 0.13V-2V.

[0183] Among them, the V / V conversion module includes:

[0184] An integrated precision voltage-dividing resistor of at least M ohm level is used to divide a wide range of voltage signals, and the connecting wires of the integrated precision voltage-dividing resistor are connected in a shielded manner.

[0185] Among them, the I / V conversion module includes:

[0186] A high-current precision 100A-level shunt is used to shunt a wide range of current signals, and the distributed inductance of the shunt is less than 80nH.

[0187] Wherein, the first automatic gain signal conditioning module and the second automatic gain signal conditioning module both include: a two-stage analog variable gain amplifier;

[0188] The first-stage analog variable gain amplifier is used to amplify the input voltage signal of the first / second low voltage range by a first-stage gain to at least 200mV;

[0189] The second stage analog variable gain amplifier is used to amplify the voltage signal with a gain of at least 200mV and perform a second-stage gain amplification to 2V.

[0190] Wherein, the phase measurement module includes:

[0191] A low phase noise clock module, used for providing a low phase noise clock signal with the same frequency and phase for the first generator DDS and the second generator DDS, and controlling the clock synchronization of the first generator DDS and the second generator DDS based on the low phase noise clock signal with the same frequency and phase;

[0192] A first generator DDS, configured to output a first analog signal to a first multiplier;

[0193] A second generator DDS, used for outputting a second analog signal to a second multiplier;

[0194] a first multiplier, configured to receive a first fixed voltage signal and the first analog signal, and perform a multiplication operation on the first fixed voltage signal and the first analog signal to generate a first multiplication operation result;

[0195] a second multiplier, configured to receive a second fixed voltage signal and the second analog signal, and perform a multiplication operation on the second fixed voltage signal and the second analog signal to generate a second multiplication operation result;

[0196] A first ADC high-speed sampler is used to sample the first multiplication result and upload the sampled first multiplication result to the processor DSP;

[0197] A second ADC high-speed sampler is used to sample the second multiplication result and upload the sampled second multiplication result to the processor DSP;

[0198] The processor DSP is used to perform calculations on the first multiplication result and the second multiplication result to determine the phases of the three-phase wide-range voltage signal and current signal.

[0199] The processor DSP performs operations on the first multiplication operation result and the second multiplication operation result, including:

[0200] Based on the first multiplication result and the second multiplication result, the phase and frequency of the first analog signal and the second analog signal are adjusted respectively to make the first analog signal orthogonal to the first fixed voltage signal and the second analog signal orthogonal to the second fixed voltage signal, and the phase control words of the first generator DDS and the second generator DDS are read according to the orthogonal result, and the phase difference between the first fixed voltage signal and the second voltage signal is calculated based on the phase control word, and the phase of the three-phase wide-range voltage signal and current signal is calculated according to the phase difference.

[0201] The present invention can precisely measure the phase of a low power factor with high accuracy.

[0202] Embodiment 3:

[0203] Based on the same inventive concept, the present invention also provides a computer device, which includes a processor and a memory, wherein the memory is used to store a computer program, the computer program includes program instructions, and the processor is used to execute the program instructions stored in the computer storage medium. The processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. It is the computing core and control core of the terminal, which is suitable for implementing one or more instructions, and is specifically suitable for loading and executing one or more instructions in the computer storage medium to implement the corresponding method flow or corresponding functions, so as to implement the steps of the method in the above embodiment.

[0204] Embodiment 4:

[0205] Based on the same inventive concept, the present invention also provides a storage medium, specifically a computer-readable storage medium (Memory), which is a memory device in a computer device for storing programs and data. It is understandable that the computer-readable storage medium here can include both a built-in storage medium in a computer device and an extended storage medium supported by the computer device. The computer-readable storage medium provides a storage space, which stores the operating system of the terminal. In addition, one or more instructions suitable for being loaded and executed by a processor are also stored in the storage space, and these instructions can be one or more computer programs (including program codes). It should be noted that the computer-readable storage medium here can be a high-speed RAM memory or a non-volatile memory, such as at least one disk memory. The processor can load and execute one or more instructions stored in the computer-readable storage medium to implement the steps of the method in the above embodiment.

[0206] It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes. The schemes in the embodiments of the present invention may be implemented in various computer languages, for example, object-oriented programming language Java and literal scripting language JavaScript, etc.

[0207] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0208] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0209] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0210] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0211] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A phase measurement system for low power factor, characterized in that: include: A phase measurement unit is used to access the three-phase wide-range voltage signal and current signal of the low power factor device, perform gain and amplitude amplification processing on the voltage signal and current signal, perform phase measurement on the processed voltage signal and current signal, and upload the phase measurement result to the communication control module; The phase measurement unit comprises: A V / V conversion module, used for receiving a three-phase wide-range voltage signal, converting the three-phase wide-range voltage signal into a voltage signal in a low-voltage range, and transmitting the voltage signal in the first low-voltage range to a first automatic gain signal conditioning module; A first automatic gain signal conditioning module, used for fixing the voltage signal in the first low voltage range to a first fixed voltage signal and inputting it into the phase measurement module; An I / V conversion module, used for receiving a three-phase wide-range current signal, converting the three-phase wide-range current signal into a voltage signal in a second low-voltage range, and transmitting the voltage signal in the second low-voltage range to a second automatic gain signal conditioning module; A second automatic gain signal conditioning module, used for fixing the voltage signal in the second low voltage range to a second fixed voltage signal and inputting it into the phase measurement module; A phase measurement module, used to measure the phases of the first fixed voltage signal and the second fixed voltage signal; The communication control module is used to read the phase measurement result.

2. The phase measurement system according to claim 1, characterized in that: The phase measurement unit comprises: phase measurement units for phase A, phase B and phase C, which are respectively used to access the wide range voltage signals and current signals of phase A, phase B and phase C of the low power factor device.

3. The phase measurement system according to claim 2, characterized in that: The voltage range of the wide-range voltage signal is: 30V-456V.

4. The phase measurement system according to claim 2, characterized in that: The voltage range of the wide-range current signal is: 0.3mA-120A.

5. The phase measurement system according to claim 1, characterized in that: The voltage range of the voltage signal in the first low voltage range and the voltage signal in the second low voltage range is 0.13V-2V.

6. The phase measurement system according to claim 1, characterized in that: The V / V conversion module comprises: An integrated precision voltage-dividing resistor of at least M ohm level is used to divide a wide range of voltage signals, and the connecting wires of the integrated precision voltage-dividing resistor are connected in a shielded manner.

7. The phase measurement system according to claim 1, characterized in that: The I / V conversion module comprises: A high-current precision 100A-level shunt is used to shunt a wide range of current signals, and the distributed inductance of the shunt is less than 80nH.

8. The phase measurement system according to claim 1, characterized in that: The first automatic gain signal conditioning module and the second automatic gain signal conditioning module both include: a two-stage analog variable gain amplifier; The first-stage analog variable gain amplifier is used to amplify the input voltage signal of the first / second low voltage range by a first-stage gain to at least 200mV; The second stage analog variable gain amplifier is used to amplify the voltage signal with a gain of at least 200mV and perform a second-stage gain amplification to 2V.

9. The phase measurement system according to claim 1, characterized in that: The phase measurement module comprises: A low phase noise clock module, used for providing a low phase noise clock signal with the same frequency and phase for the first generator DDS and the second generator DDS, and controlling the clock synchronization of the first generator DDS and the second generator DDS based on the low phase noise clock signal with the same frequency and phase; A first generator DDS, configured to output a first analog signal to a first multiplier; A second generator DDS, used for outputting a second analog signal to a second multiplier; a first multiplier, configured to receive a first fixed voltage signal and the first analog signal, and perform a multiplication operation on the first fixed voltage signal and the first analog signal to generate a first multiplication operation result; a second multiplier, configured to receive a second fixed voltage signal and the second analog signal, and perform a multiplication operation on the second fixed voltage signal and the second analog signal to generate a second multiplication operation result; A first ADC high-speed sampler is used to sample the first multiplication result and upload the sampled first multiplication result to the processor DSP; A second ADC high-speed sampler is used to sample the second multiplication result and upload the sampled second multiplication result to the processor DSP; The processor DSP is used to perform calculations on the first multiplication result and the second multiplication result to determine the phases of the three-phase wide-range voltage signal and current signal.

10. The phase measurement system according to claim 9, characterized in that: The processor DSP performs operations on the first multiplication operation result and the second multiplication operation result, including: Based on the first multiplication result and the second multiplication result, the phase and frequency of the first analog signal and the second analog signal are adjusted respectively to make the first analog signal orthogonal to the first fixed voltage signal and the second analog signal orthogonal to the second fixed voltage signal, and the phase control words of the first generator DDS and the second generator DDS are read according to the orthogonal result, and the phase difference between the first fixed voltage signal and the second voltage signal is calculated based on the phase control word, and the phase of the three-phase wide-range voltage signal and current signal is calculated according to the phase difference.

11. A phase measurement method using any one of the phase measurement systems for low power factor according to claims 1-10, characterized in that: include: Accessing the three-phase wide-range voltage signal and current signal of the low power factor device through the phase measurement unit, performing gain and amplitude amplification processing on the voltage signal and current signal, performing phase measurement on the processed voltage signal and current signal, and uploading the phase measurement result to the communication control module; Wherein, a three-phase wide-range voltage signal is connected through a V / V conversion module of a phase measurement unit, the three-phase wide-range voltage signal is converted into a voltage signal in a low-voltage range, and the voltage signal in the first low-voltage range is transmitted to a first automatic gain signal conditioning module; Fixing the voltage signal in the first low voltage range as a first fixed voltage signal and inputting it into the phase measurement module through a first automatic gain signal conditioning module of the phase measurement unit; Accessing a three-phase wide-range current signal through an I / V conversion module of the phase measurement unit, converting the three-phase wide-range current signal into a voltage signal in a second low-voltage range, and transmitting the voltage signal in the second low-voltage range to a second automatic gain signal conditioning module; Fixing the voltage signal in the second low voltage range as a second fixed voltage signal and inputting it into the phase measurement module through a second automatic gain signal conditioning module of the phase measurement unit; Measuring the phases of the first fixed voltage signal and the second fixed voltage signal by a phase measurement module of a phase measurement unit; The phase measurement result is read through the communication control module.

12. The phase measurement method according to claim 11, characterized in that: The phase measurement unit comprises: phase measurement units for phase A, phase B and phase C, which are respectively used to access the wide range voltage signals and current signals of phase A, phase B and phase C of the low power factor device.

13. The phase measurement method according to claim 12, characterized in that: The voltage range of the wide-range voltage signal is: 30V-456V.

14. The phase measurement method according to claim 12, characterized in that: The voltage range of the wide-range current signal is: 0.3mA-120A.

15. The phase measurement method according to claim 11, characterized in that: The voltage range of the voltage signal in the first low voltage range and the voltage signal in the second low voltage range is 0.13V-2V.

16. The phase measurement method according to claim 11, characterized in that: The V / V conversion module comprises: An integrated precision voltage-dividing resistor of at least M ohm level is used to divide a wide range of voltage signals, and the connecting wires of the integrated precision voltage-dividing resistor are connected in a shielded manner.

17. The phase measurement method according to claim 11, characterized in that: The I / V conversion module comprises: A high-current precision 100A-level shunt is used to shunt a wide range of current signals, and the distributed inductance of the shunt is less than 80nH.

18. The phase measurement method according to claim 11, characterized in that: The first automatic gain signal conditioning module and the second automatic gain signal conditioning module both include: a two-stage analog variable gain amplifier; The first-stage analog variable gain amplifier is used to amplify the input voltage signal of the first / second low voltage range by a first-stage gain to at least 200mV; The second stage analog variable gain amplifier is used to amplify the voltage signal with a gain of at least 200mV and perform a second-stage gain amplification to 2V.

19. The phase measurement method according to claim 11, characterized in that: The phase measurement module comprises: A low phase noise clock module, used for providing a low phase noise clock signal with the same frequency and phase for the first generator DDS and the second generator DDS, and controlling the clock synchronization of the first generator DDS and the second generator DDS based on the low phase noise clock signal with the same frequency and phase; A first generator DDS, configured to output a first analog signal to a first multiplier; A second generator DDS, used for outputting a second analog signal to a second multiplier; a first multiplier, configured to receive a first fixed voltage signal and the first analog signal, and perform a multiplication operation on the first fixed voltage signal and the first analog signal to generate a first multiplication operation result; a second multiplier, configured to receive a second fixed voltage signal and the second analog signal, and perform a multiplication operation on the second fixed voltage signal and the second analog signal to generate a second multiplication operation result; A first ADC high-speed sampler is used to sample the first multiplication result and upload the sampled first multiplication result to the processor DSP; A second ADC high-speed sampler is used to sample the second multiplication result and upload the sampled second multiplication result to the processor DSP; The processor DSP is used to perform calculations on the first multiplication result and the second multiplication result to determine the phases of the three-phase wide-range voltage signal and current signal.

20. The phase measurement method according to claim 19, characterized in that: The processor DSP performs operations on the first multiplication operation result and the second multiplication operation result, including: Based on the first multiplication result and the second multiplication result, the phase and frequency of the first analog signal and the second analog signal are adjusted respectively to make the first analog signal orthogonal to the first fixed voltage signal and the second analog signal orthogonal to the second fixed voltage signal, and the phase control words of the first generator DDS and the second generator DDS are read according to the orthogonal result, and the phase difference between the first fixed voltage signal and the second voltage signal is calculated based on the phase control word, and the phase of the three-phase wide-range voltage signal and current signal is calculated according to the phase difference.

21. A computer device, characterized in that: include: one or more processors; a processor for executing one or more programs; When the one or more programs are executed by the one or more processors, the method according to any one of claims 11 to 20 is implemented.

22. A computer-readable storage medium, characterized in that: A computer program is stored thereon, and when the computer program is executed, the method according to any one of claims 11 to 20 is implemented.

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