CN204287858U - A kind of intelligent agriculture row table - Google Patents

Abstract

An intelligent agriculture row table, relates to automation control area, particularly electricity meter-reading and automatic control device in agricultural irrigation, for power information collection and the management of power department.Structure comprises CPU, the data acquisition unit be connected with CPU, telecommunication unit, display unit, storage unit, magnetic field detection unit, take and control unit, battery, mobile public network communication module or power line carrier, PLC module are set in described telecommunication unit, described magnetic field detection unit arranges three, also comprises relay test unit in structure.Adopt this scheme, the optimization of the protection and battery that can solve the communication issue of backcountry agriculture row table, stealing problem and motor uses.

Description

An intelligent farm schedule

technical field

The utility model relates to the field of automatic control, in particular to electric meter reading and automatic control devices in agricultural irrigation.

Background technique

The location of the wells on the agricultural irrigation site is relatively scattered and most of the wells are located in a location where the transportation is inconvenient. At the same time, agricultural irrigation and drainage equipment is usually installed and used in areas with complex environments, which brings great difficulties to the collection and management of electricity consumption information in the power sector. . At present, there are mainly the following problems:

1. Communication problem. With the development of mobile communication networks, the means of using the mobile public network for information transmission has been widely used. Some of the on-site wells for agricultural irrigation are located in remote areas and cannot be covered by the public network. Therefore, this method cannot solve the communication problem of all on-site wells. Meter reading can only be done by manual hand-held acquisition devices to collect data one by one on site, and then enter them in a centralized manner. , with the rapid increase in the number of users, manual collection faces many difficulties, increases a lot of labor costs and management costs, and cannot meet the construction of "full coverage, full collection, and full prepayment" proposed by the State Grid Corporation of China for the electricity consumption information collection system Target. At the same time, the chaotic on-site power consumption and the corresponding line loss analysis consume a lot of manpower and material resources, and the real-time performance is seriously lagging behind and the accuracy is seriously insufficient. Moreover, even if the public network can cover the area, the use of the public network will inevitably involve communication costs.

Carrier communication using power lines is also a technical means widely used at present. Most of the power loads of the power lines for agricultural row are three-phase three-wire balanced load motors. In order to reduce costs and reduce construction difficulties, in remote areas, most of the power supply is 3*380V three-phase three-wire system, and there is no N wire in the three-phase three-wire system. Ordinary carrier communication cannot perform zero-crossing detection, and carrier communication cannot be realized.

2. Electricity theft problem. The problem of electricity theft has become more and more prominent in the society. According to conservative estimates, the annual loss of electricity due to theft of electricity in the whole country reaches 20 billion yuan. This not only plagues the development of power supply companies, but also seriously affects the country's economic construction and social stability. At present, the electric energy meter is generally installed in a special metering box, and the cable enters and exits through the pipeline, and the metering box is locked. Recently, there has been a phenomenon of using strong magnets to absorb electricity on the metering box near the electric energy meter. The method is concealed, easy to remove, and has a tendency to spread. The principle is: the load switch inside the meter uses a magnetic latching relay. Since the magnetic latching relay is a magnetic field sensitive device, the opening and closing state of the relay can be changed by applying an external magnetic field, which can affect the opening and closing action of the relay and achieve the purpose of stealing electricity. In addition, the power supply of the electric energy meter is mostly a power frequency transformer. The strong magnetic field can reduce the efficiency of the power frequency transformer and increase the power consumption of the electric energy meter.

At present, the means of anti-strong magnetic stealing electricity mainly include:

Shielding method is adopted: install a metal shielding shell outside the meter, and raise the meter inside the metering box, so that the meter is far away from the metering box in all directions. Using this method, it can withstand a constant magnetic field attack of 300mT, ensuring that the state will not be affected. If the magnetic field strength continues to increase and exceeds the upper limit, the shielding shell will fail.

Adopt active power-off mode: install magnetic contact switch, when strong magnetism is sensed, cut off the power supply circuit. This technology is described in Chinese patents "CN 103149429 A" and "CN 203385773 U".

Adopt the relay state detection method: the existing relay detection method is generally: the relay outputs the switch state node through the internal synchronization mechanism, and connects to the processor port for detection. This detection method does not detect the real circuit on-off state. If there is a problem with the relay synchronization mechanism, the relay state will not be detected correctly.

The above-mentioned protection methods have single function, limited effect, and poor reliability, and cannot detect electricity theft behavior in time, and cannot meet the requirements of electricity theft prevention.

3. The power failure detection problem of the electric energy meter. Energy meters are mostly powered by power frequency transformers. Strong magnetic fields can reduce the efficiency of power frequency transformers and increase the power consumption of the power meters. The transformers cannot provide enough voltage to power the power meters to work, causing the power meters to fail to start and measure. If the energy meter cannot detect such failures in time, it will cause huge losses in electricity bills. The existing electric energy meter power failure detection method is generally as follows: after the system is powered off, the system is powered by a backup battery, the processor turns on the switch of the metering chip, initializes the metering chip, reads the metering parameters from the memory and sends them to the metering chip, After the metering chip is running normally, read the AC voltage value in the metering chip to judge whether the external power supply is normal. This process requires the metering chip and memory to be powered on, which consumes a lot of power and takes a long time, which consumes a lot of battery power.

4. Battery passivation problem. The clock battery of the electric energy meter adopts a lithium sub-battery. Although the lithium sub-battery has a large capacity, there is a passivation problem when used. After the battery is passivated, it cannot output enough voltage for a short time, causing the energy meter to work abnormally, especially causing the clock of the energy meter to be inaccurate, which seriously affects the function of the energy meter.

The existing battery anti-passivation technologies mainly include the following:

1. Electric energy storage method:

The battery is connected in parallel with the supercapacitor, and the battery charges the supercapacitor slowly during the rest period, and the supercapacitor is directly powered by the supercapacitor when a large current pulse is required. The disadvantages of this method are mainly cost and self-discharge. The price of the super capacitor is close to or even exceeds the price of the battery itself, which greatly increases the cost. In addition, the super capacitor has a large leakage current, which increases the self-discharge rate and the service life of the battery. cut short. It cannot meet the requirements of 10-year service life of electric energy meter and 5-year battery power supply.

2. Balance current method

Let the battery always maintain a reasonable discharge current, which is just enough to eliminate the produced passivation layer in a timely and uniform manner. The passivation speed of the battery is affected by the temperature. The operating temperature range of the electric energy meter is -40 to 70 degrees. The fixed balance current cannot be adjusted according to the temperature on site. If the current is too small, it is not enough to eliminate passivation. If the current is too high, it will decrease Little battery life.

3. Timing activation method

Regularly conduct a pulse discharge of a larger battery to break down the passivation film just formed. Since the degree of passivation of the cell cannot be determined, there is also the problem of under-activation or over-activation.

Although the current technology can prevent battery passivation to a certain extent, for the electric energy meter, it has a long service life, a large temperature range, and operates outdoors. The above characteristics determine that the electric energy meter is not suitable for the above open-loop way to prevent battery passivation.

5. The protection of the motor. In remote areas, most of the power supply is 3*380V three-phase three-wire system. If the relay's three-phase switch status is inconsistent due to its own failure or other reasons, it will cause a phase loss fault. The most important equipment for agricultural drainage and irrigation is a three-phase motor. A phase failure will have a serious impact on the electrical equipment for agricultural drainage and even burn the motor directly.

Contents of the invention

The purpose of this utility model is to provide an intelligent farming table to solve the above-mentioned problems in the prior art.

In order to achieve the above object, the technical solution adopted by the utility model is: a kind of intelligent farming table, including CPU, a data acquisition unit connected with the CPU, a remote communication unit, a display unit, a storage unit, a magnetic field detection unit, a battery, The key lies in: the remote communication unit is provided with a mobile public network communication module or a power carrier communication module, the magnetic field detection unit is provided with three groups, and the structure also includes a relay detection unit.

The preferred solution: the power carrier communication module is at the strong current interface, and the B phase is connected to the N phase terminal, and the original B phase terminal is suspended in the air.

The preferred solution: the relay detection unit is provided in three groups, respectively connected to the ABC three-phase; the relay detection unit includes a voltage divider circuit, a control switch circuit, a strong and weak current isolation circuit, a pull-up resistor and a pulse detection circuit.

Further, a battery anti-passivation unit is also included.

Adopt the technical scheme that this application proposes:

1. According to the site conditions, the public network communication module or power carrier communication module can be used to communicate with the remote end, which solves the problem of single remote communication and communication means, especially the power carrier communication method based on three-phase three-wire, which overcomes remote The poor site conditions in the area make it impossible to communicate.

2. By detecting the actual switch state of the relay on the three-phase line, it can be found and reported in time when electricity theft occurs, reducing losses, and can also judge power failure based on this to ensure the normal operation of the meter.

3. Through the anti-passivation unit of the battery, the degree of passivation of the battery can be accurately detected, and different discharge methods are adopted according to the degree of passivation to eliminate the passivation film of the battery in time, effectively preventing the battery from under-discharging or In case of overdischarge.

4. The detection circuit of the agricultural meter relay can also monitor the voltage of each phase. If a phase failure is detected in the power supply line, the relay will disconnect to protect the motor. The agricultural meter uses the metering chip to detect parameters such as voltage, current, power, and power factors in real time. When the voltage is unbalanced, the current is unbalanced, the power exceeds the limit, and the power factor is sharply increased, the relay will be disconnected in time to protect the user's motor and report to the main station. After alarming, the main station sends a notification to the agricultural row users, and it can operate normally only after troubleshooting, protecting the fixed assets of the agricultural row users from loss. the

Description of drawings

Figure 1 is a schematic diagram of the working principle and composition of the agricultural platoon table.

Figure 2 is a functional block diagram of the relay detection unit,

Figure 3 is a schematic diagram of the relay detection unit,

Figure 4 is a functional block diagram of the battery anti-passivation unit,

Figure 5 is a schematic diagram of the battery anti-passivation unit,

Figure 6 is a schematic diagram of the installation position of the magnetic field detection unit in the agricultural row table,

Fig. 7 is a schematic diagram of the voltage selection circuit of the magnetic field detection unit,

Figure 8 is a schematic diagram of the installation layout of the linear Hall sensor.

In Fig. 7, 1 is the agricultural row table, and 2 is a schematic diagram of the installation position of the magnetic field detection unit.

Detailed ways

Below in conjunction with accompanying drawing, the utility model is further described.

Referring to Fig. 1, a structure of an intelligent agricultural meter includes a CPU, a data acquisition unit connected to the CPU, a remote communication unit, a display unit, a storage unit, a magnetic field detection unit, a fee control unit, a battery anti-passivation unit, a battery, and a relay Detection unit, power supply and management module, etc.

The field application environment of agricultural irrigation and drainage meters is complex. The power carrier communication module is affected by distance and high-frequency interference, and the wireless public network module is affected by the signal strength of the base station. In the utility model, a mobile public network communication module or a power carrier communication module is arranged in the remote communication unit, and in practical application, the staff can select a more suitable communication mode according to the site conditions.

The traditional carrier communication modules are all applied on the basis of the three-phase four-wire system, corresponding to four terminals, which are respectively connected to the A phase, B phase, C phase and N phase. Most of the power loads of power lines for agricultural platoons are three-phase three-wire balanced load motors. In order to reduce costs and reduce construction difficulties, most of the power supply is 3*380V three-phase three-wire system. There is no N wire in the three-phase three-wire system. Ordinary carrier communication In this mode, zero-crossing detection and carrier communication cannot be performed.

The utility model designs a three-phase three-wire transceiver circuit for the zero-crossing detection circuit of the carrier communication, and can realize the carrier communication in a line without a zero line. Taking phase B as a reference, the waveform frequency of phase A and phase C is still 50Hz. At the strong current interface of the carrier module, connect phase B to the position of phase N. The original position of phase B is suspended, and use the waveform between AB and CB Change to carry out zero-crossing detection and realize the communication of three-phase three-wire power line carrier. In this embodiment, Dingxin carrier module is used.

Referring to Figure 2, the relay detection unit includes a voltage divider circuit, a control switch circuit, a strong and weak current isolation circuit, a pull-up resistor and a pulse detection circuit. There are three units in this unit, which are respectively connected to ABC three-phase relays.

Referring to Figure 2 and Figure 3, the CPU is connected to each relay detection unit through two control signals: CTRL and TEST. The input of the circuit is AC voltage. When the circuit is working, the CPU opens the circuit through the CTRL port. After the resistor divides the voltage, the voltage drops to the working voltage range of the optocoupler and the diode, so that the optocoupler is turned on periodically. When the optocoupler is turned on, The TEST port is low level; when the optocoupler is cut off, the TEST port is pulled up by the resistor to be high level, so the CPU can detect the pulse signal at the TEST port, if there is no voltage signal at the AC input terminal, the TEST port is a continuous high level .

Relay state detection principle: CTRL end outputs high level, when the relay is closed, the optocoupler conducts periodically, and TEST end outputs pulse signal to CPU with a frequency of 50Hz; when the relay is disconnected, the optocoupler does not conduct, and TEST end is continuous high level. The CPU can judge the on-off state of the relay by detecting the level state of the TEST terminal. The thyristor is used in the circuit to control the on-off of the primary circuit, and the thyristor is only turned on during detection, which reduces the power consumption of the circuit. The watt-hour meter detects the opening and closing status of the relay in real time through the voltage detection circuit. When the actual state of the relay is found to be inconsistent with the command state, the watt-hour meter resends the command. If the state is still inconsistent after three times, it is judged that the relay has malfunctioned, and the meter records the event. It is transmitted to the background master station through the communication module.

The power failure can also be detected through the relay detection unit: after the power failure of the electric energy meter, the electric meter runs in a low power consumption state, and the power detection circuit is turned on through the backup battery, the CTRL terminal outputs a high level, and the CPU detects the state of the TEST terminal level , to determine whether there is voltage at the power supply terminal, if there is voltage at the power supply terminal, but the energy meter cannot start normally, it is judged that a power failure has occurred, the energy meter records the event, and the communication module transmits the event to the background master station through the backup battery to remind the background staff in time deal with. In the state where the relay is disconnected, since the agricultural meter cannot output voltage, even if a strong magnetic interference event occurs, it will not cause the consequences of stealing electricity.

The agricultural meter is an outdoor installation product. The environment for agricultural drainage and irrigation is complex, and electricity theft occurs from time to time. This circuit can effectively monitor the attack on the agricultural meter relay and power supply at the power site, quickly and accurately detect the fault, and report it in real time. To the power management department, it is convenient for the management personnel to deal with it in a timely manner, and the order of agricultural drainage and irrigation power consumption is standardized.

Referring to Figure 4 and Figure 5, the battery anti-passivation unit includes a battery passivation detection circuit composed of an equivalent load resistance connected to the battery and a detection switch connected to the CPU, a pulse discharge resistor connected to the battery and a pulse discharge switch connected to the CPU A pulse discharge circuit and two resistors connected to the battery in series form a micro-current balance circuit.

The battery passivation detection circuit includes an equivalent load resistance composed of resistors R3 and R4 and a detection switch K1, R3, R4, and K1 are connected in series, K1 is connected to the CPU, R3 is connected to the battery, and the A/D detection terminal of the CPU is connected to Between the two resistors R3 and R4;

In the pulse discharge circuit, the pulse discharge resistor R5 is connected to the battery, and connected to the pulse discharge switch K2, and K2 is connected to the CPU;

The micro-current balance circuit is composed of resistors R1 and R2 connected in series to the battery. In order to achieve the purpose of micro-current discharge, R1 and R2 adopt large resistance values.

The working process of each circuit is as follows:

Battery passivation detection circuit: When the external power supply is working, K1 is closed, and the A/D detection voltage is the open circuit voltage of the battery, which is not affected by passivation. If the open circuit voltage is less than 3.0V, it means that the battery is undervoltage, and the ammeter records pressure event. If the open circuit voltage is above 3.0V, the processor turns on the K1 switch for 1000ms every hour to discharge the battery through the equivalent resistance. At this time, the voltage detected by the A/D conversion channel is the voltage when the battery is loaded. If the loaded voltage is 3.0 If the voltage is higher than 2.8V and less than 3.0V, keep K1 open, discharge the battery for 10 seconds, and read the A/D detection voltage continuously. If the voltage If it remains unchanged or becomes smaller, K1 is turned off. If the voltage rises, it is judged that the battery is passivated, and K1 is kept on until the battery voltage no longer rises, the passivation is eliminated, and K1 is turned off.

Pulse discharge circuit: When it is detected that the battery may be in deep passivation (battery load voltage is less than 2.8V), turn on the K2 switch and perform pulse discharge on the battery through R5. The time lasts for 100ms, and the battery voltage is detected until the voltage no longer rises, and K1 and K2 are turned off. If the battery voltage does not rise, it means that the battery is not passivated and the battery power is low. At this time, turn off K1 and K2 and record the battery undervoltage time.

In the micro-current balance circuit, R1 and R2 adopt large resistance resistors. When the electric energy meter does not need battery power supply, the battery can maintain a discharge current of about 1uA, which will not affect the service life of the battery, and can prevent the battery from generating at room temperature. The passivation film reduces the number of times the passivation detection circuit and the pulse discharge circuit are turned on, and reduces the number of times the battery is discharged.

The battery passivation detection circuit is adopted, and different discharge methods are adopted according to the degree of passivation to eliminate the passivation film of the battery in time, effectively preventing the battery from under-discharging or over-discharging during the process of eliminating passivation.

The electric energy meter installed on site is susceptible to magnetic field interference from the left and right sides and the upper side of the front, and the lower side is where the wire connection cannot be approached by strong magnetism. See Figure 6. Three sets of magnetic field detection units are set in the new smart agricultural row meter 1. They are respectively installed on the left and right sides and the upper side of the inner front of the agricultural row table 1, as indicated by 2. Each group of magnetic field detection units uses three linear Hall devices. The surfaces of the three linear Hall devices are perpendicular to each other and can detect the magnetic field strength in the three axial directions of X, Y, and Z. The settings on the circuit board are shown in Figure 8. It shows that the detection range of the three groups of detection units can cover the entire range of magnetic field interference that the electric energy meter may be subjected to.

The magnetic field sensor is a linear Hall device, and the field strength is a vector. A single Hall device can only collect signals in one axis. Each group of magnetic field detection units uses three discrete linear Hall sensors to form a three-axis magnetic sensor. The output of the linear Hall sensor is an analog quantity, which needs to be converted by AD to obtain the strength of the magnetic field. If an AD channel is assigned to each sensor, each energy meter uses 3 detection units, and 9 AD conversion channels are required, which takes up huge system resources. The utility model designs a voltage selection circuit, and each detection unit only needs one channel to detect the magnetic field intensity at the position of the sensor.

Referring to Fig. 7, the voltage selection circuit includes a comparison amplifier, an exclusive OR gate circuit and an analog switch, the level control output of the CPU is connected to the input terminal of the exclusive OR gate, and the output of the exclusive OR gate circuit controls the analog switch.

When the circuit is working, the X-axis sensor signal is compared and amplified with the Y-axis sensor signal, and the output signal is XORed with the level control signal of the processor. The result of the operation controls the output of the analog switch. When the level control signal is high, the circuit Select the one with the higher voltage among the XY axis signals and compare it with the Z axis signal to select the signal with the highest voltage in the three directions; when the level control signal is low, you can select the signal with the lowest voltage in the three directions Signal. The power supply voltage of the Hall device is 5V. In a non-magnetic field environment, the output voltage is 2.5V. When the N\S pole magnetic fields are detected to be close to each other, the voltage changes to 0V and 5V respectively, and the processor changes the level control port in time-sharing. The strongest magnetic field signal can be selected.

After the selected signal is filtered, it enters the AD conversion circuit of the processor, and the field strength can be calculated, and the magnetic field interference generated by which unit can be determined.

The electricity environment for agricultural drainage and irrigation is complicated, and the phenomenon of electricity theft occurs from time to time. This circuit can set the detection threshold according to the actual installation environment on site. According to the detection result, the CPU compares the A/D converted value with the detection threshold. If it exceeds the threshold range, a magnetic field greater than a certain intensity is generated. By changing the threshold, the strength of the magnetic field alarm can be changed. The detected data is stored and reported to the background, which facilitates timely processing by the power consumption management unit, and regulates the order of agricultural drainage and irrigation power consumption.

The utility model is installed and operated in Shijiazhuang, Qinhuangdao and other areas. It realizes the function of automatic remote copying and pre-purchasing electricity, greatly improves the work efficiency of the power bureau, realizes the real-time monitoring and monitoring function of line loss, and has perfect functions and good performance. , has been unanimously praised by users.

Claims (6)

1. an intelligent agriculture row table, structure comprises CPU, the data acquisition unit be connected with CPU, telecommunication unit, display unit, storage unit, magnetic field detection unit, take and control unit, battery, it is characterized in that: mobile public network communication module or power line carrier, PLC module are set in described telecommunication unit, described magnetic field detection unit arranges three, also comprises relay test unit in structure.

2. one according to claim 1 intelligent agriculture row table, is characterized in that: B phase, at forceful electric power interface, is connected to N and connects terminal by described power line carrier, PLC module, and the former B terminal that connects is unsettled.

3. one according to claim 1 intelligent agriculture row table, is characterized in that: described relay test unit arranges three, connects the relay of ABC three-phase respectively; Relay test unit comprises bleeder circuit, gauge tap circuit, strong and weak electricity buffer circuit, pull-up resistor and pulse-detecting circuit.

4. one according to claim 1 intelligent agriculture row table, it is characterized in that: also comprise the anti-passivation unit of battery, the pulse discharge circuit that the battery passivation testing circuit that the equivalent load resistance that battery anti-passivation unit comprises connection battery forms with the detector switch being connected to CPU, the pulsed discharge resistance being connected battery and the pulsed discharge switch being connected to CPU form and two resistant series being connected battery form micro-current balance circuit.

5. one according to claim 1 intelligent agriculture row table, is characterized in that: three groups of described magnetic field detection cellular installations show the left and right sides and the upside in inner front agriculture row; Often organize magnetic field detection unit and adopt three discrete linear hall sensors, the surface of three linear hall-effect devices is mutually vertical, composition magnetic sensor.

6. one according to claim 5 intelligent agriculture row table, is characterized in that: the output of three discrete linear hall sensors, through voltage selecting circuit, a road signal is given the A/D detection port of CPU; Voltage selecting circuit comprises comparison amplifier, NOR gate circuit and analog switch, and the Automatic level control of CPU exports the input end connecting XOR gate, the output control simulation switch of NOR gate circuit.