A universal AC / DC hybrid smart meter

Abstract

The invention discloses an AC / DC hybrid universal intelligent electric meter, comprising a metering module and a main control module; the metering module comprises: a voltage sensing module, a current sensing module, a metering chip module, and an isolation module; the voltage sensing module and the current sensing module are used to convert and process the instantaneous values ​​of the voltage and current of the circuit to be measured, so that the metering chip can sample and obtain the voltage and current information that meets the sampling standard; the main control module comprises: a main controller, a digital display module, a liquid crystal display module, and a wireless communication module; the main controller is used to control the metering chip sampling circuit parameters to perform calculation processing and other functional management; it can distinguish between AC and DC power supplies, can measure the power consumption of AC and DC power supplies, and when a fault occurs, it can identify the fault signal, and can wirelessly send its fault waveform to a PC end, and can display it on a display screen, so as to realize the measurement and monitoring of the AC and DC power supplies.

Description

Technical Field

[0001] The invention relates to an AC / DC hybrid universal intelligent electric meter, belonging to the technical field of electric power. Background Art

[0002] The rapid economic development can be reflected in all aspects, especially in the demand for electricity. Nowadays, every household and every corner has a variety of different electrical items, so accurate measurement of electricity is particularly important. In 2009, my country proposed to establish a digital, information-based, automated, and interactive smart grid, but the network access between the power metering device and the power system is still relatively backward. For example, in the past, there was a kind of meter that only had a metering function and required manual meter reading, which obviously could not meet the needs of social development. Nowadays, the development of direct current and alternating current is very rapid, such as the alternating current that enters every household and the direct current used in electric vehicles. There is a great demand, but the existing smart meters on the market that can measure both AC and DC are rare. Summary of the invention

[0003] The purpose of the present invention is to provide an AC / DC hybrid universal smart meter to solve the problems raised in the above background technology. It can overcome the above existing problems, distinguish between AC and DC power supplies, measure the power consumption of AC and DC power supplies, and when a fault occurs, it can identify the fault signal, send its fault waveform wirelessly to the PC end, and display it on the display screen, thereby realizing the measurement and monitoring of AC and DC power supplies.

[0004] To achieve the above-mentioned purpose, the present invention adopts the following technical solutions: an AC / DC hybrid universal smart meter, comprising a metering module and a main control module;

[0005] The metering module includes: a voltage sensing module, a current sensing module, a metering chip module, and an isolation module. The voltage sensing module and the current sensing module are used to convert and process the instantaneous values ​​of the voltage and current of the circuit to be tested, so that the metering chip can sample and obtain voltage and current information that meets the sampling standard;

[0006] The metering chip module is controlled by the main controller, and the instantaneous values ​​of voltage and current in the sampling circuit are calculated and processed, and transmitted to the main controller;

[0007] Isolation module, used to optically isolate the metering chip from the main controller to avoid mutual interference;

[0008] The main control module includes: main controller, digital display module, liquid crystal display module, wireless communication module;

[0009] The main controller is used to control the sampling circuit parameters of the metering chip for calculation and processing and other functional management;

[0010] The digital display module is used to display the power consumption parameters calculated by the main controller;

[0011] The liquid crystal display module is used to display the fault current when the main controller determines that a fault has occurred;

[0012] The wireless communication module is used to receive and send information.

[0013] The voltage and current sensing module uses one Hall voltage sensor and two current sensors respectively, which can convert the parameters of the AC and DC circuits into proportional AC and DC signals respectively, and connect to the three ADC sampling entrances of the current and voltage input of the metering chip. The metering chip uses the metering chip RN8209D, which is a special metering chip for preventing electricity theft in the power grid. It provides two current and one voltage effective value measurements. Like other chips, it can measure AC and DC circuit energy at the same time. Unlike AC measurement, it needs to add DC bias correction to provide a realistic basis for the mixed use of AC and DC. It is controlled by the main controller to sample and calculate different AC and DC circuits. The isolation module uses TI's I The SO7420 isolation device realizes isolated communication between the metering module and the main control module to ensure safe operation. The main controller uses the STM32F407 minimum system as the processing unit, which is used to control the metering chip sampling circuit information to distinguish between AC and DC for corresponding power calculation and manage the output of other functional modules. The digital tube module 5 uses a 5-bit common cathode digital tube to display the calculated power data. The LCD display module uses a 0.96-inch OLED LCD screen to display the fault current waveform. The wireless communication module is a CC2530 system-on-chip for human-computer interaction. The power module uses a switch network and a TPS77033 voltage regulator chip to power the microcontroller.

[0014] A control method for an AC / DC hybrid universal smart meter. After the system is powered on and reset and the system program is initialized, it is first determined whether 2s have passed since the last digital tube update data. If so, the new metering parameters are updated and the active power is sent to the host computer through CC2530. If not, it waits for the main controller STM32F407 to generate a 1s interrupt flag. If not, it continues to wait. If so, it reads the data sampled by the metering chip RN8209D to determine whether it is AC or DC. After accumulating electric energy, if it is DC, power correction is required (for AC, the metering chip has this function). Then, the flag used to indicate the number of times is set. Bit TIME+1, when TIME is greater than the set threshold, it means that there is no fault during this period of time, and it is cleared. If not, it continues to run. At this time, the presence of a flat shoulder area at the zero point of the sampled current waveform is used to determine whether an arc has occurred at this time. When it is determined that a flat shoulder area appears, the waveform is displayed on OLED, and the counting variable FAULT+1 is increased. When FAULT is greater than the set threshold, it indicates that arcs have occurred frequently in the past short period of time, indicating that there is a problem with the main line. At this time, a request is sent to the control end through the wireless module to cut off the power supply to ensure the safety of power users. If none of these occur, the system is judged to be normal and the next cycle is performed.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] 1 Due to the different properties of AC and DC power supplies, for AC circuits, the magnitude and direction of voltage and current are constantly changing.

[0017] There is a phase difference between the two, while the DC circuit has no phase difference, so the calculation formulas for the power of AC and DC power supplies are different. The main controller controls the metering chip to perform calculations, thereby realizing the power calculation of the AC and DC circuits.

[0018] 2 Due to the programmability of the main controller, all parameters in the circuit can be analyzed and processed, which can be more

[0019] It can also display various required power consumption parameters in the circuit to users and operators.

[0020] 3. If a fault occurs in the main circuit, it will be reflected in the current and voltage waveforms, so the system can be judged through programming whether

[0021] In case of a fault, online monitoring function is realized, which is more intelligent.

[0022] 4. Through the wireless transmission module, remote control can be realized, circuit parameters can be remotely monitored, and they can be programmed.

[0023] Process and correction.

[0024] 5Since the single chip microcomputer can process and control data without pressure, there is no need to use a faster speed

[0025] ARM control chip reduces manufacturing costs and makes control simple and convenient.

[0026] 6 Since the metering chip can collect two currents, inflow and outflow, it can also prevent electricity theft. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a circuit schematic diagram of an AC / DC hybrid universal smart meter of the present invention;

[0028] Figure 2 This is a circuit diagram of an AC / DC hybrid universal smart meter of the present invention;

[0029] Figure 3 It is a flow chart of the present invention. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0031] An AC / DC hybrid universal smart meter, comprising a metering module 1 and a main control module 2;

[0032] The metering module 1 includes: a voltage sensing module 3, a current sensing module 4, a metering chip module 5, and an isolation module 6. The voltage sensing module 3 and the current sensing module 4 are used to convert and process the instantaneous values ​​of the voltage and current of the circuit to be measured, so that the metering chip can sample and obtain voltage and current information that meets the sampling standard;

[0033] The metering chip module 5 is controlled by the main controller, and the instantaneous values ​​of the voltage and current in the sampling circuit are calculated and processed, and transmitted to the main controller;

[0034] Isolation module 6, used to optically isolate the metering chip from the main controller to avoid mutual interference;

[0035] The main control module 2 includes: a main controller 7, a digital display module 8, a liquid crystal display module 9, and a wireless communication module 10;

[0036] The main controller 7 is used to control the sampling circuit parameters of the metering chip to perform calculations and other functional management;

[0037] The digital display module 8 is used to display the power consumption parameters calculated by the main controller;

[0038] The liquid crystal display module 9 is used to display the fault current when the main controller determines that a fault has occurred;

[0039] The wireless communication module 10 is used to receive and send information;

[0040] The voltage and current sensing module 1 uses a Hall voltage sensor and two current sensors respectively, which can convert the parameters of the AC and DC circuits into proportional AC and DC signals respectively, and connect to the three ADC sampling entrances of the current and voltage input of the metering chip 2. The metering chip 2 uses the metering chip RN8209D, which is a special metering chip for preventing electricity theft in the power grid. It provides two current and one voltage effective value measurements. Like other chips, it can measure AC and DC circuit energy at the same time. Unlike AC measurement, it needs to add DC bias correction to provide a realistic basis for realizing AC and DC mixed use. It is controlled by the main controller to sample and calculate different AC and DC circuits. The isolation module 3 uses TI's I The SO7420 isolation device realizes isolated communication between the metering module and the main control module to ensure safe operation. The main controller 4 uses the minimum system model STM32F407 as the processing unit, which is used to control the metering chip sampling circuit information to distinguish between AC and DC to perform corresponding power calculations and manage the outputs of other functional modules. The digital tube module 5 uses a 5-bit common cathode digital tube to display the calculated power data. The liquid crystal display module 6 uses a 0.96-inch OLED liquid crystal display to display the fault current waveform. The wireless communication module 7 is a CC2530 on-chip system for realizing human-computer interaction. The power supply module 8 uses a switch network and a TPS77033 voltage regulator chip to power the microcontroller.

[0041] A control method for an AC / DC hybrid universal smart meter. After the system is powered on and reset and the system program is initialized, it is first determined whether 2s have passed since the last digital tube update data. If so, the new metering parameters are updated and the active power is sent to the host computer through CC2530. If not, it waits for the main controller STM32F407 to generate a 1s interrupt flag. If not, it continues to wait. If so, it reads the data sampled by the metering chip RN8209D to determine whether it is AC or DC. After accumulating electric energy, if it is DC, power correction is required (for AC, the metering chip has this function). Then, the flag used to indicate the number of times is set. Bit TIME+1, when TIME is greater than the set threshold, it means that there is no fault during this period of time, and it is cleared. If not, it continues to run. At this time, the presence of a flat shoulder area at the zero point of the sampled current waveform is used to determine whether an arc has occurred at this time. When it is determined that a flat shoulder area appears, the waveform is displayed on OLED, and the counting variable FAULT+1 is increased. When FAULT is greater than the set threshold, it indicates that arcs have occurred frequently in the past short period of time, indicating that there is a problem with the main line. At this time, a request is sent to the control end through the wireless module to cut off the power supply to ensure the safety of power users. If none of these occur, the system is judged to be normal and the next cycle is performed.

[0042] The principle of the present invention is: the line parameters of the original line are transformed through the voltage and current sensor modules. Since the selected sensor module can transform both AC and DC, it is the basis for realizing AC and DC mixed use. Then, the instantaneous value of current and voltage in the circuit is sampled by a professional metering chip. The chip function determines that it can calculate the power of both AC and DC, which is an important reason for realizing AC and DC mixed use meters. The main controller analyzes and calculates the instantaneous value data of voltage and current obtained by controlling the metering chip, and accumulates the calculated electric energy, thereby realizing the function of the AC and DC mixed use meter and timing. It is displayed through a digital display tube. When a fault occurs in the main circuit, an arc is generated in the line and a flat shoulder area will appear in the current waveform. At this time, the main control determines whether there is a flat shoulder area through a threshold number of zero crossing points. If it is determined that a flat shoulder area appears, the current data is saved and displayed on the LCD module. A number threshold is then used to determine the number of times the flat shoulder area occurs within a certain period of time to determine whether a fault occurs. When a fault is determined to occur, it is sent wirelessly to the remote control personnel to cut off the power supply, ensuring that the AC and DC power supplies can be measured at the same time and the fault can be monitored. This overcomes the defects of existing measuring meters and has better practical effects.

[0043] The above is a preferred embodiment of the present invention. For ordinary technicians in this field, according to the teachings of the present invention, without departing from the principles and spirit of the present invention, changes, modifications, substitutions and variations made to the implementation methods are still within the scope of protection of the present invention.

Claims

1. A control method for an AC / DC hybrid universal smart meter, which is applied to an AC / DC hybrid universal smart meter, wherein the AC / DC hybrid universal smart meter includes a metering module and a main control module; The metering module includes: a voltage sensing module, a current sensing module, a metering chip module, and an isolation module. The voltage sensing module and the current sensing module are used to convert and process the instantaneous values ​​of the voltage and current of the circuit to be measured, so that the metering chip can sample and obtain voltage and current information that meets the sampling standard; the metering chip module is controlled by the main controller, and the instantaneous values ​​of the voltage and current in the sampling circuit are calculated and processed, and transmitted to the main controller; the isolation module is used to photoelectrically isolate the metering chip from the main controller to avoid mutual interference; the main control module includes: a main controller, a digital display module, a liquid crystal display module, and a wireless communication module; the main controller is used to control the parameters of the metering chip sampling circuit for calculation and processing and other functional management; the digital display module is used to display the power consumption parameters calculated by the main controller; the liquid crystal display module is used to display the fault current when the main controller determines that a fault has occurred; the wireless communication module is used to receive and send information, and the voltage and current sensor modules use 1 Hall voltage sensor respectively The device and two current sensors can convert AC and DC circuit parameters into proportional AC and DC signals respectively, and are connected to the three ADC sampling entrances of the current and voltage input of the metering chip. The metering chip adopts the metering chip RN8209D, which provides two current and one voltage effective value measurement. It can measure AC and DC circuit energy at the same time. Unlike AC measurement, it needs to add DC bias correction, which provides a practical basis for realizing AC and DC mixed use. Under the control of the main controller, different AC and DC circuits are sampled and calculated. The isolation module adopts the ISO7420 isolation device of TI Company to realize the isolated communication between the metering module and the main control module to ensure safe operation. The main controller adopts the minimum system of STM32F407 as the processing unit, which is used to control the sampling circuit information of the metering chip to distinguish AC and DC to perform corresponding power calculation and manage the output of other functional modules. The digital tube module (5) adopts a 5-bit common cathode digital tube to display the calculated power data. The liquid crystal display module adopts 0.The 96-inch OLED LCD display is used to display the fault current waveform. The wireless communication module is a CC2530 system-on-chip, which is used to realize human-computer interaction. The power module uses a switch network to use a TPS77033 voltage regulator chip to power the microcontroller. The control method is characterized in that after the system is powered on and reset and the system program is initialized, it is first determined whether 2s have passed since the last digital tube update data. If so, the new metering parameters are updated and the active power is sent to the host computer through CC2530. If not, it waits for the main controller STM32F407 to generate a 1s interrupt flag. If not, it continues to wait. If yes, it reads the data sampled by the metering chip RN8209D to determine whether it is AC or DC, and accumulates the electric energy. After the integration, if it is DC, power correction is required, and then the flag bit TIME used to indicate the number of times is increased by 1. When TIME is greater than the set threshold, it means that there is no fault during this period of time, and it is cleared. If not, it continues to run. At this time, the presence of the flat shoulder area at the zero point of the sampled current waveform is used to determine whether an arc has occurred at this time. When it is determined that a flat shoulder area appears, the waveform is displayed on OLED, and the counting variable FAULT+1 is increased. When FAULT is greater than the set threshold, it indicates that arcs have occurred frequently in the past short period of time, indicating that there is a problem with the main line. At this time, the wireless module is sent to the control end to request to cut off the power supply to ensure the safety of power users. If none of these occur, the system is judged to be normal and the next cycle is carried out. .

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