A high-precision power monitoring system with fast response based on a metering chip

Abstract

A high-precision power monitoring system based on the fast response of a metering chip, which is set as side A and side B for different power supply circuits. The number of acquisition channels on side A and side B is the same, both being 24 voltage and current channels, and the structures are the same. Side A and side B respectively include a current sampling circuit, a voltage sampling circuit, a digital control analog switch unit, a metering chip unit, and an isolation chip unit. The isolation chip units are all connected to the main control single-chip microcomputer MCU. The 24 current sampling circuits and voltage sampling circuits are respectively connected to the digital control analog switch units of each channel, the digital control analog switch units are all connected to the metering chip unit, and the metering chip unit is connected to the isolation chip unit. The present invention can not only meet the high precision of electrical parameters, but also optimize the response speed of the change of electrical parameter data on the basis of the traditional metering chip solution, which is a practical and effective solution.

Description

Technical Field

[0001] The present invention relates to the technical field of intelligent monitoring of distribution cabinets, and particularly to a high-precision power energy monitoring system based on fast response of a metering chip. Background Art

[0002] At present, a large number of acquisition modules are installed in the field of precision power distribution in data centers. These modules collect electrical parameter data and breaker status at the end of low-voltage power distribution to ensure the power supply reliability and stability of products such as low-voltage power distribution, backup generator sets, uninterruptible power supplies, backup batteries, and precision power distribution in data centers. For products in data centers, especially like row head cabinets, due to the large number of power distribution circuits, for the monitoring system, it is necessary to be able to collect electrical parameter data of multiple channels.

[0003] For the traditional multi-channel monitoring module solution, one is that the voltage and current of multiple circuits enter the MCU main control chip after passing through an analog switch. This solution is only applicable to the scenario where the power supply voltage of precision power distribution is not isolated. If the power supply voltage is isolated and needs to be collected, 2 sets of monitoring modules are required for this solution, which greatly increases the equipment cost and installation cost. For example, Chinese Patent CN202050158U provides a monitoring device for a precision power distribution cabinet. If it involves the situation of incoming line voltage isolation, 2 sets of incoming line modules and feeder modules are required.

[0004] Another circuit solution is that after multiple metering chips operate on the multi-channel voltage and current sampling circuit, data interaction is carried out with the main control MCU through SPI communication. For example, Chinese Patent CN202916335U provides a three-phase ammeter based on a single-phase metering chip. This solution is relatively mature in market application. For the situation where the number of sampling channels is relatively small, the data response speed effect is good. However, as the number of sampling channels increases, the response timeliness of this solution will become worse and worse. And the data center has certain response requirements for the changes in the status of breakers and the like, and this solution cannot meet the requirements.

[0005] Therefore, there is an urgent need for a high-precision power energy monitoring system based on fast response of a metering chip. Summary of the Invention

[0006] The purpose of the present invention is to overcome the above deficiencies and provide a high-precision power energy monitoring system based on fast response of a metering chip. It adopts a high-precision multi-channel isolation scheme based on a metering chip. The power energy measurement accuracy can reach 0.5 level. A single module can measure up to 48 channels of electrical parameters such as voltage, current, and power at the same time, and has a data response rate of less than 1 s. At the same time, it also has a phase sequence adjustment mechanism; it can perform real-time online data monitoring on products such as row head cabinets in the data center.

[0007] The purpose of the present invention is achieved as follows:

[0008] A high-precision power monitoring system based on the fast response of a metering chip. It is set as side A and side B for different power supply circuits. The number of acquisition channels on side A and side B is the same, both being 24 channels of voltage and current, and the structures are the same. Side A and side B respectively include a current sampling circuit, a voltage sampling circuit, a digital control analog switch unit, a metering chip unit, and an isolation chip unit. The isolation chip units are all connected to the main control single-chip microcomputer MCU. The 24 current sampling circuits and voltage sampling circuits are respectively connected to the digital control analog switch units of each channel. The digital control analog switch units are all connected to the metering chip unit, and the metering chip unit is connected to the isolation chip unit.

[0009] When the 24 channels of voltage and current obtain a certain sampling voltage through voltage division and other methods, the MCU sends data to the digitally controlled analog switch unit through the isolation chip unit, switches the corresponding voltage and current loop numbers, and then switches the ADC sampling values of the voltage and current of this loop to the metering chip unit through the digitally controlled analog switch unit. The metering chip unit communicates with the main control single-chip microcomputer MCU in SPI communication mode through the isolation chip unit. After the MCU obtains the ADC sampling values, it performs logical operation processing to obtain corresponding true effective values, harmonics and other data.

[0010] Further, in the voltage sampling circuit, when there is a voltage of 220V between INA_UA1 and UNA_UN, the voltage is divided by RA1, RA2, RA3 and R6, and R6 is also the sampling resistor at the same time. The sampling voltage of UA1 is obtained through this sampling resistor. R7, C12 and C13 play a filtering role and can reduce the interference caused by the AC line. The Q1 diode protects the circuit and prevents the voltage on this circuit from being too large and damaging the ADC channel of the subsequent metering chip.

[0011] Further, in the current sampling circuit, when the secondary milliampere-level current signal enters from J1, R3 and R4 are current sampling resistors. Through this sampling resistor, the sampling voltage of the current loop entering the metering chip can be obtained. R2, C1, R5 and C10 are RC filtering circuits, which can reduce the interference caused by the AC line. The VD1 diode protects the circuit and prevents the voltage on this circuit from being too large and damaging the ADC channel of the subsequent metering chip.

[0012] Further, for the DC sampling scheme in the current sampling circuit, a compatible resistor R1 reserved when the DC Hall 5V is connected is also provided.

[0013] Further, the chip in the digitally controlled analog switch module switching circuit is an 8-to-1 channel switch. By controlling the ABC in the chip, the ADC sampling values of the voltage and current of the corresponding channel are switched. At the same time, if the phase sequence error problem is encountered in the actual field, the corresponding channel number can be adjusted to adjust the phase sequence problem between the voltage and current.

[0014] Further, in the metering chip circuit, the ADC sampling accuracy of the metering chip is high, and it can simultaneously collect the ADC sampling values of 3 channels of voltage and 3 channels of current. This metering chip can perform data interaction with the MCU through SPI, and the MCU performs data interaction with multiple metering chips through SPI.

[0015] Further, in the isolation chip circuit, the communication rate of the isolation chip is high, ensuring that the high-precision ADC sampling values collected by the metering chip are transmitted to the MCU within 1 s.

[0016] Further, the isolation chip circuit meets the corresponding isolation requirements, ensuring normal acquisition even when the power supply voltage is in different circuits.

[0017] Further, after the MCU obtains the corresponding voltage and current ADC sampling values, logical operation processing is performed. After Fourier transform DFT operation, the real part and imaginary part of the corresponding voltage and current values are obtained. In addition, the CORDIC algorithm is used to calculate the real part and imaginary part corresponding to the current voltage value and current value respectively, and the corresponding harmonic voltage angle and harmonic current angle are obtained; after obtaining the corresponding values of voltage and current, the active power, reactive power, power factor, and electric energy are obtained.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0019] (1) The voltage, current, and power measurement accuracies of the present invention are very high. The electric energy measurement accuracy can reach level 1.0, and the linear consistency of the product within the range can be ensured.

[0020] (2) The present invention is a multi-channel isolation scheme based on a metering chip. The single-sided acquisition loop has 24 channels, and the A side and the B side are isolated from each other, which can ensure that different power supply circuits will not affect each other during monitoring. At the same time, the accuracy of electrical parameter measurement is ensured. When measuring different power supply circuits with the number of loops less than 24, only one acquisition module is required, reducing the equipment cost.

[0021] (3) When the external electrical parameters change, the monitoring system of the present invention has a data refresh rate of less than 1 s. After the data refresh rate is increased, the full cycle of the distribution circuit can be monitored, and the monitoring data of the distribution circuit is more accurate.

[0022] (4) The present invention has a phase sequence adjustment mechanism, which can perform phase sequence adjustment between voltage and current without power interruption, ensuring the accuracy of distribution circuit monitoring, and at the same time avoiding the safety hazards and time-consuming and laborious maintenance costs brought by manual wire replacement. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the system framework of the present invention.

[0024] Figure 2 This is a partial circuit diagram of the voltage sampling circuit of the present invention.

[0025] Figure 3 This is a partial circuit diagram of the current sampling circuit of the present invention.

[0026] Figure 4 This is the circuit schematic diagram of the analog switch module switching circuit of the present invention.

[0027] Figure 5 This is the circuit schematic diagram of the metering chip circuit of the present invention.

[0028] Figure 6 This is the circuit schematic diagram of the isolation chip circuit of the present invention.

[0029] Figure 7 This is the schematic diagram of the process for the MCU of the present invention to process the collected ADC sampling values. Detailed implementation manners

[0030] To better understand the technical solution of the present invention, the following will be described in detail with reference to relevant drawings. It should be understood that the following specific embodiments are not intended to limit the specific implementation forms of the technical solution of the present invention, and they are only the implementation forms that the technical solution of the present invention can adopt. It should be noted first that the description of the positional relationship between components herein, such as component A is located above component B, is based on the relative positions of the components in the drawings and is not intended to limit the actual positional relationship of the components.

[0031] Embodiment 1:

[0032] Refer to Figures 1 - 7 , Figure 1 , a structural schematic diagram of the present invention is drawn. As shown in the figure, a high-precision power monitoring system based on rapid response of a metering chip according to the present invention is provided. For different power supply circuits, it is set as side A and side B. The number of acquisition channels on side A and side B is the same, both are 24 voltage and current channels, and the structures are the same. Side A and side B respectively include a current sampling circuit, a voltage sampling circuit, a digital control analog switch unit, a metering chip unit, and an isolation chip unit. The isolation chip units are all connected to the main control single-chip microcomputer MCU. The 24 current sampling circuits and voltage sampling circuits are respectively connected to the digital control analog switch units of each path. The digital control analog switch units are all connected to the metering chip unit, and the metering chip unit is connected to the isolation chip unit.

[0033] When the sampling voltage is obtained by voltage division and other methods from 24 channels of voltage and current, the MCU sends data to the digitally controlled analog switch unit through the isolation chip unit, switches the corresponding number of voltage and current loops, and then switches the ADC sampling values of the voltage and current of this loop to the metering chip unit through the digitally controlled analog switch unit. The metering chip unit communicates with the main control MCU in SPI communication mode through the isolation chip unit. After the MCU obtains the ADC sampling values, it performs various logical operations to obtain corresponding true RMS values, harmonics and other data.

[0034] See Figure 2 , Figure 2 is a partial circuit diagram of the voltage sampling circuit. Only one channel of voltage sampling is listed here, and the same applies to the other 47 channels of voltage; when there is a voltage of 220V (maximum 1.2 times overload, 264V) between INA_UA1 and UNA_UN, the voltage is divided by RA1, RA2, RA3 and R1, and R1 is also the sampling resistor at the same time. The sampling voltage of UA1 is obtained through this sampling resistor. R7, C12 and C13 play a filtering role and can reduce the interference caused by the AC line. The diode Q1 protects the circuit and prevents the voltage on this circuit from being too large and damaging the ADC channel of the subsequent metering chip.

[0035] See Figure 3 , Figure 3 is a partial circuit diagram of the current sampling circuit. Only one channel of current sampling is listed here, and the same applies to the other 47 channels of current; when the secondary milliampere-level current signal enters from J1, R3 and R4 are the current sampling resistors. Through this sampling resistor, the sampling voltage of this current loop entering the metering chip can be obtained. R10, R2, C1, R5 and C10 are RC filtering circuits, which can reduce the interference caused by the AC line. The diode VD1 protects the circuit and prevents the voltage on this circuit from being too large and damaging the ADC channel of the subsequent metering chip; R9 is a compatible resistor reserved for the DC Hall 5V access.

[0036] See Figure 4 , Figure 4 is the switching circuit diagram of the digitally controlled analog switch module. The chip in this circuit is an 8-to-1 channel switch. By controlling the ABC (the value ranges from 000 - 111) in the chip, the ADC sampling values of the voltage and current of the corresponding channel are switched. At the same time, if there is a phase sequence error problem in the actual field, the corresponding number of channels can be adjusted to correct the phase sequence problem between the voltage and current.

[0037] See Figure 5 , Figure 5It is the circuit schematic diagram of the metering chip circuit. This chip has high ADC sampling accuracy and can simultaneously collect the ADC sampling values of 3 channels of voltage and 3 channels of current. While ensuring the sampling accuracy, it functions as an analog-to-digital conversion chip. This metering chip can perform data interaction with the MCU through SPI. Compared with the traditional method of obtaining the corresponding electrical parameter values after the operation of the metering chip, the MCU performs data interaction with multiple metering chips through SPI. This solution greatly speeds up the response speed of the electrical parameter data and also ensures the accuracy of the electrical parameters.

[0038] See Figure 6 , Figure 6 It is the circuit schematic diagram of the isolation chip circuit. This chip has relatively high communication rate requirements and can ensure that the high-precision ADC sampling values collected by the metering chip are transmitted to the MCU in a very short time, ensuring the response speed of the electrical parameter data and meeting the requirement within 1 s. At the same time, this circuit also needs to meet the corresponding isolation requirements to ensure normal sampling when the power supply voltage is in different circuits.

[0039] See Figure 7 , Figure 7 It is the processing flow chart of the ADC sampling values collected in the MCU. After the MCU obtains the corresponding ADC sampling values of voltage and current, the real and imaginary parts of the corresponding voltage and current values are obtained through the Fourier transform DFT operation. In addition, the CORDIC algorithm is used to calculate the real and imaginary parts corresponding to the current voltage value and current value respectively to obtain the corresponding harmonic voltage angle and harmonic current angle. After obtaining the corresponding values of voltage and current, the active power, reactive power, power factor, and electric energy can be obtained.

[0040] The design method of the present invention based on the metering chip can not only meet the high precision of electrical parameters, but also optimize the response speed of the change of electrical parameter data on the basis of the traditional metering chip solution, which is a practical and effective solution.

[0041] Working principle:

[0042] The monitoring system of the present invention includes a current sampling circuit, a voltage sampling circuit, a digitally controlled analog switch module, a metering chip module, an isolation chip module, and a main control microcontroller module MCU. The present invention is designed with an A side and a B side for different power supply circuits. The number of sampling channels on the A side and the B side is the same, both being 24. This design enables the module to operate normally regardless of whether the power supply circuits are of the same voltage. When the 24 voltage and current values are used to obtain a certain sampling voltage through voltage division or other means, the MCU sends data to the digitally controlled analog switch module through the isolation chip module, switches the corresponding number of voltage and current circuits, and then switches the ADC sampling values of the voltage and current of this circuit to the metering chip through the digitally controlled analog switch module. The metering chip communicates with the main control microcontroller module MCU in SPI communication mode through the isolation chip module. After obtaining the ADC sampling values, the MCU performs various logical operations to obtain corresponding true effective values, harmonic data, etc.

[0043] The above are only specific application examples of the present invention and do not constitute any limitation to the protection scope of the present invention. Any technical solutions formed by equivalent transformation or equivalent substitution fall within the scope of the rights protection of the present invention.

Claims

1. A high-precision power monitoring system based on the rapid response of a metering chip, characterized in that: It is set into an A side and a B side for different power supply circuits. The number of acquisition channels on the A side and the B side is the same, both being 24 voltage and current channels, and the structures are the same; the A side and the B side respectively include a current sampling circuit, a voltage sampling circuit, a digital control analog switch unit, a metering chip unit, and an isolation chip unit. The isolation chip units are all connected to the main control single-chip microcomputer MCU. The 24 current sampling circuits and voltage sampling circuits are respectively connected to the digital control analog switch units of each path. The digital control analog switch units are all connected to the metering chip unit, and the metering chip unit is connected to the isolation chip unit; When the 24 voltage and current values obtain a certain sampling voltage through a voltage division method, the MCU sends data to the digitally controlled analog switch unit through the isolation chip unit, switches the corresponding number of voltage and current circuits, and then switches the ADC sampling values of the voltage and current of this circuit to the metering chip unit through the digitally controlled analog switch unit. The metering chip unit communicates with the main control single-chip microcomputer MCU in an SPI communication manner through the isolation chip unit. After the MCU obtains the ADC sampling values, it performs logical operation processing to obtain the corresponding true effective value and harmonic data.

2. A high-precision power monitoring system based on the rapid response of a metering chip according to claim 1, characterized in that: In the voltage sampling circuit, when there is a voltage of 220V between INA_UA1 and UNA_UN, the voltage is divided by RA1, RA2, RA3, and R6, and R6 is also the sampling resistor at the same time. The sampling voltage of UA1 is obtained through this sampling resistor. R7, C12, and C13 play a filtering role and can reduce the interference caused by the AC line. The Q1 diode plays a protective role for the circuit to prevent the voltage on this circuit from being too large and damaging the ADC channel of the subsequent metering chip.

3. A high-precision power monitoring system based on the rapid response of a metering chip according to claim 1, characterized in that: In the current sampling circuit, when the secondary milliamp-level current signal enters from J1, R3 and R4 are current sampling resistors. Through this sampling resistor, the sampling voltage of this current circuit entering the metering chip can be obtained. R2, C1, R5, and C10 are RC filtering circuits, which can reduce the interference caused by the AC line. The VD1 diode plays a protective role for the circuit to prevent the voltage on this circuit from being too large and damaging the ADC channel of the subsequent metering chip.

4. A high-precision power monitoring system based on the rapid response of a metering chip according to claim 3, characterized in that: In the current sampling circuit for the DC sampling scheme, a compatible resistor R1 reserved when the DC Hall 5V is connected is also provided.

5. A high-precision power monitoring system based on the rapid response of a metering chip according to claim 1, characterized in that: The chip in the digital-controlled analog switch module switching circuit is an 8-to-1 channel switch. By controlling ABC in the chip, the voltage and current ADC sampling values of the corresponding channels are switched. At the same time, if a phase sequence error problem is encountered in the actual field, the corresponding number of channels can be adjusted to correct the phase sequence problem between the voltage and current.

6. A high-precision power monitoring system based on a fast-response metering chip according to claim 1, characterized in that: In the metering chip circuit, the ADC sampling accuracy of the metering chip is high, and it can simultaneously collect the ADC sampling values of 3 channels of voltage and 3 channels of current. The metering chip can perform data interaction with the MCU through SPI, and the MCU performs data interaction with multiple metering chips through SPI.

7. A high-precision power monitoring system based on a fast-response metering chip according to claim 1, characterized in that: In the isolation chip circuit, the communication rate of the isolation chip is high, ensuring that the high-precision ADC sampling values collected by the metering chip are transmitted to the MCU within 1 s.

8. A high-precision power monitoring system based on a fast-response metering chip according to claim 1, characterized in that: The isolation chip circuit meets the corresponding isolation requirements, ensuring normal acquisition even when the power supply voltage is in different circuits.

9. A high-precision power monitoring system based on a fast-response metering chip according to claim 1, characterized in that: After the MCU obtains the corresponding voltage and current ADC sampling values, logical operation processing is performed. After Fourier transform DFT operation, the real and imaginary parts of the corresponding voltage and current values are obtained. In addition, the CORDIC algorithm is used to calculate the real and imaginary parts corresponding to the current voltage value and current value respectively, and the corresponding harmonic voltage angle and harmonic current angle are obtained; after obtaining the corresponding values of the voltage and current, the active power, reactive power, power factor, and electric energy are obtained.

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