Voltage and current detection system with good anti-interference effect

Abstract

The utility model discloses a voltage and current detection system with a good anti-interference effect, and belongs to the field of electric energy monitoring. The system comprises a voltage acquisition module, a current acquisition module, a sensor signal conditioning circuit, a current signal conditioning circuit, a voltage signal conditioning circuit, a multipath signal switching module, a voltage division following filter circuit, an ADE7878 electric energy chip, a controller module, a display module, a data transmission module, a data storage module, an alarm module, an input setting module and a timing module. The electric quantity data acquisition module is used for acquiring electric quantity data through voltage detection and current detection, voltage and current signals acquired by the mutual inductor are converted into signals which can be processed by the controller by utilizing the current and voltage measuring circuit, and then the single chip microcomputer is directly used for directly acquiring the signals. The anti-interference effect is good, and the measurement precision is high.

Description

Technical Field

[0001] The utility model belongs to the field of electric energy monitoring, and particularly relates to a voltage and current detection system with good anti-interference effect. Background Technique

[0002] At present, in the fire alarm linkage system, when a fire occurs due to abnormal power supply of fire-fighting equipment (such as fire pumps, fans, emergency lighting, etc.), the entire fire alarm linkage system cannot work properly, seriously affecting the evacuation of personnel and the extinguishment of fires, threatening people's lives and property safety.

[0003] Regarding the current monitoring of data during the operation of fire-fighting power supply equipment to avoid faults such as overvoltage, undervoltage, overcurrent, open circuit, short circuit, and phase loss during the fire-fighting process, which will affect the fire-fighting work. Generally, the monitoring of fire-fighting power supply equipment only detects and feedbacks at regular intervals, cannot monitor and feedback in real time, and thus cannot timely understand the data status of fire-fighting power supply equipment, which may delay the normal fire-fighting work. Content of the Utility Model

[0004] The technical problem to be solved by the utility model is to provide a voltage and current detection system with good anti-interference effect for the deficiencies of the background technique. The voltage or current signals obtained by the mutual inductor are converted by using a current and voltage measurement circuit into signals that can be processed by a controller, and then the signals are directly collected by a single-chip microcomputer. It has good anti-interference effect and high measurement accuracy.

[0005] The utility model adopts the following technical solutions to solve the above technical problems

[0006] A voltage and current detection system with good anti-interference effect, comprising a voltage acquisition module, a current acquisition module, a sensor signal conditioning circuit, a current signal conditioning circuit, a voltage signal conditioning circuit, a multi-channel signal switching module, a voltage-dividing follower filtering circuit, an ADE7878 power chip, a controller module, a display module, a data transmission module, a data storage module, an alarm module, an input setting module, a timing module, an interface module and a power supply module; the power supply module includes a voltage source and an overvoltage protection circuit connected thereto; the output ends of the voltage acquisition module are respectively connected to the input ends of the sensor signal conditioning circuit, the current signal conditioning circuit and the voltage signal conditioning circuit, the output ends of the current acquisition module are respectively connected to the input ends of the sensor signal conditioning circuit, the current signal conditioning circuit and the voltage signal conditioning circuit, the output ends of the sensor signal conditioning circuit, the current signal conditioning circuit and the voltage signal conditioning circuit are connected to the input end of the multi-channel signal switching module, the output end of the multi-channel signal switching module is connected to the input end of the voltage-dividing follower filtering circuit, the output end of the voltage-dividing follower filtering circuit is connected to the input end of the ADE7878 power chip, the output end of the ADE7878 power chip is connected to the input end of the controller module, and the display module, the data transmission module, the data storage module, the alarm module, the input setting module, the timing module, the interface module and the power supply module are respectively connected to the controller module.

[0007] As a further preferred solution of the voltage and current detection system with good anti-interference effect of the present utility model, the controller module includes a high-stability crystal oscillator module, an FPGA main control module, a USB transmission module, a serial port module, a data processing center, a USB interface, a gigabit network interface and an HDMI interface. The high-stability crystal oscillator module is connected to the FPGA main control module. The FPGA main control module is respectively connected to the data processing center through the SB transmission module and the serial port module. The USB interface, the gigabit network interface and the HDMI interface are respectively connected to the data processing center.

[0008] As a further preferred solution of the voltage and current detection system with good anti-interference effect of the present utility model, the overvoltage protection circuit includes a reference voltage circuit and a feedback control circuit.

[0009] As a further preferred solution of the voltage and current detection system with good anti-interference effect of the present utility model, the sensor signal conditioning circuit includes an analog signal input terminal, a resistor R1, a resistor R2, a capacitor C1, and an operational amplifier U1. The analog signal input terminal is respectively connected to one end of the resistor R1 and one end of the resistor R2. The other end of the resistor R2 is connected to one end of the capacitor C1. The other end of the capacitor C1 is respectively connected to the other end of the resistor R1 and the positive input terminal of the operational amplifier U1. The negative input terminal of the operational amplifier U1 is connected to the output terminal of the operational amplifier U1.

[0010] As a further preferred embodiment of the voltage and current detection system with good anti-interference effect of the present utility model, the voltage signal conditioning circuit includes a voltage signal input terminal, a resistor R3, a resistor R4, a resistor R5, a capacitor C2, and an operational amplifier U2. The voltage signal input terminal is connected to one end of the resistor R3. The other end of the resistor R3 is respectively connected to one end of the resistor R4 and one end of the resistor R5. The other end of the resistor R5 is connected to one end of the capacitor C2. The other end of the capacitor C2 is respectively connected to the other end of the resistor R4 and the positive input terminal of the operational amplifier U1. The negative input terminal of the operational amplifier U2 is connected to the output terminal of the operational amplifier U2.

[0011] As a further preferred embodiment of the voltage and current detection system with good anti-interference effect of the present utility model, the current signal conditioning circuit uses the ACS714 chip of Allegro Company. This chip is a current isolation type current sensor with a common-mode rejection field effect and is composed of a high-precision low-offset linear Hall sensor.

[0012] As a further preferred embodiment of the voltage and current detection system with good anti-interference effect of the present utility model, the voltage division follower filtering unit includes an operational amplifier U3, a resistor R11, a resistor R12, an operational amplifier U4, a resistor R13, and a capacitor C7. The output terminal of the operational amplifier U3 is connected to one end of the resistor R12. The other end of the resistor R12 is respectively connected to one end of the resistor R11 and the positive input terminal of the operational amplifier U4. The output terminal of the operational amplifier U4 is connected to one end of the resistor R13. The other end of the resistor R13 is respectively connected to one end of the capacitor C7 and the A / D conversion unit. The other end of the capacitor C7 is grounded. The other end of the resistor R11 is connected to the current signal conditioning circuit.

[0013] As a further preferred embodiment of the voltage and current detection system with good anti-interference effect of the present utility model, the chip model of the multi-channel signal switching module is CD4052 / CC4052.

[0014] Compared with the prior art, the present utility model adopts the above technical solutions and has the following technical effects:

[0015] 1. The voltage and current detection system with good anti-interference effect of the present utility model includes a voltage acquisition module, a current acquisition module, a sensor signal conditioning circuit, a current signal conditioning circuit, a voltage signal conditioning circuit, a multi-channel signal switching module, a voltage division follower filtering circuit, an ADE7878 power chip, and a controller module. It completes the acquisition of power data through voltage detection and current detection, uses the current and voltage measurement circuits to convert the voltage or current signals obtained by the mutual inductor into signals that can be processed by the controller, and then directly uses the single-chip microcomputer to directly perform signal acquisition. It has good anti-interference effect and high measurement accuracy;

[0016] 2. The utility model uses an ADE7878 power chip to realize the acquisition of multi-channel power data, and within the rated sampling range of each power data, the accuracy can reach 1%. The circuit is simple, with flexible application, high accuracy, and low cost.

[0017] 3. The utility model processes the collected voltage and current signals through signal conditioning, analog switches, voltage division and following, and anti-aliasing filtering in sequence, analyzes the establishment time of the link, and then uses a successive approximation type AD chip for conversion. The collected signals have higher accuracy, are more stable and reliable. The specific filter circuit filters the amplified power parameters, and then uploads the stable and reliable power parameters to the controller module. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is the overall system structure schematic diagram of a voltage and current detection system with good anti-interference effect of the utility model;

[0019] Figure 2 is the structure schematic diagram of the controller module of the utility model;

[0020] Figure 3 is the circuit diagram of the sensor signal conditioning circuit of the utility model;

[0021] Figure 4 is the circuit diagram of the voltage signal conditioning circuit of the utility model;

[0022] Figure 5 is the circuit diagram of the voltage division and following filter unit of the utility model. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] The technical solutions of the utility model will be further described in detail below with reference to the drawings:

[0024] The hardware modules involved in the utility model all belong to existing functional hardware modules, and their functional principles, specific circuits, and connection and usage methods all belong to the common technical knowledge of those skilled in the art;

[0025] A voltage and current detection system with good anti-interference effect, such as Figure 1As shown in the figure, it includes a voltage acquisition module, a current acquisition module, a sensor signal conditioning circuit, a current signal conditioning circuit, a voltage signal conditioning circuit, a multi-channel signal switching module, a voltage division follower filtering circuit, an ADE7878 power chip, a controller module, a display module, a data transmission module, a data storage module, an alarm module, an input setting module, a timing module, an interface module, and a power supply module; the power supply module includes a voltage source and an overvoltage protection circuit connected thereto; the output ends of the voltage acquisition module are respectively connected to the input ends of the sensor signal conditioning circuit, the current signal conditioning circuit, and the voltage signal conditioning circuit, the output ends of the current acquisition module are respectively connected to the input ends of the sensor signal conditioning circuit, the current signal conditioning circuit, and the voltage signal conditioning circuit, the output ends of the sensor signal conditioning circuit, the current signal conditioning circuit, and the voltage signal conditioning circuit are connected to the input end of the multi-channel signal switching module, the output end of the multi-channel signal switching module is connected to the input end of the voltage division follower filtering circuit, the output end of the voltage division follower filtering circuit is connected to the input end of the ADE7878 power chip, the output end of the ADE7878 power chip is connected to the input end of the controller module, and the display module, the data transmission module, the data storage module, the alarm module, the input setting module, the timing module, the interface module, and the power supply module are respectively connected to the controller module.

[0026] As Figure 2 shown in the figure, the controller module includes a high-stability crystal oscillator module, an FPGA main control module, a USB transmission module, a serial port module, a data processing center, a USB interface, a gigabit network interface, and an HDMI interface. The high-stability crystal oscillator module is connected to the FPGA main control module. The FPGA main control module is respectively connected to the data processing center through the SB transmission module and the serial port module. The USB interface, the gigabit network interface, and the HDMI interface are respectively connected to the data processing center.

[0027] The overvoltage protection circuit includes a reference voltage circuit and a feedback control circuit.

[0028] As Figure 3 shown in the figure, the sensor signal conditioning circuit includes an analog signal input terminal, a resistor R1, a resistor R2, a capacitor C1, and an operational amplifier U1. The analog signal input terminal is respectively connected to one end of the resistor R1 and one end of the resistor R2. The other end of the resistor R2 is connected to one end of the capacitor C1. The other end of the capacitor C1 is respectively connected to the other end of the resistor R1 and the positive input terminal of the operational amplifier U1. The negative input terminal of the operational amplifier U1 is connected to the output terminal of the operational amplifier U1.

[0029] As a key device in the conditioning circuit, the operational amplifier selected in this utility model is the AD8608 operational amplifier chip of Analog Devices, Inc. This chip combines many excellent characteristics. It has four-channel rail-to-rail input and output while being powered by a single supply, and can ensure extremely low noise and input bias current while maintaining high speed, and is widely applicable to various circuits;

[0030] Since the input impedance of the operational amplifier is generally very high, when the input pin is floating, it is extremely vulnerable to external interference. Therefore, setting the resistor R2 can form a loop between the input terminal and the analog ground when the input pin is floating, ensuring the stability of the operational amplifier.

[0031] Such as Figure 4 As shown, the voltage signal conditioning circuit includes a voltage signal input terminal, a resistor R3, a resistor R4, a resistor R5, a capacitor C2, and an operational amplifier U2. The voltage signal input terminal is connected to one end of the resistor R3, and the other end of the resistor R3 is respectively connected to one end of the resistor R4 and one end of the resistor R5. The other end of the resistor R5 is connected to one end of the capacitor C2, and the other end of the capacitor C2 is respectively connected to the other end of the resistor R4 and the positive input terminal of the operational amplifier U1. The negative input terminal of the operational amplifier U2 is connected to the output terminal of the operational amplifier U2.

[0032] In the voltage conditioning circuit, the rail-to-rail operational amplifier can maximize the input and output voltage swings close to the power supply voltage value, but there are still large deviations in the case of large currents. Since the input voltage range of the AD8608 is 0 to 0.5V, the resistors R3 and R5 are set to form a voltage divider circuit to reduce the input voltage below 5V.

[0033] For the magnitude of the current and the difference between AC and DC, the corresponding current acquisition methods are also different. Commonly used current acquisition methods include the coaxial shunt method, the current transformer method, the Rogowski coil method, the Hall sensor method, and the sampling resistor method, etc. The Hall sensor method is applicable to the measurement of both AC and DC currents and can measure large currents. The current signal conditioning circuit uses the ACS714 chip of Allegro MicroSystems, LLC. This chip is a current isolation type current sensor with a common-mode rejection field effect and is composed of a high-precision low-offset linear Hall sensor.

[0034] The FGPA is used to control the analog switch to select and gate the address switching channel to achieve the effect of time division multiplexing. When switching channels, the analog switch will affect the change of the capacitive load, resulting in phenomena such as signal oscillation or ringing. The faster the switching speed of the analog switch, the more obvious this phenomenon is. Therefore, the selection of the analog switch is particularly important. By analyzing and comparing various different types of analog switches, the ADG706 chip is adopted in this design.

[0035] The current signal conditioning circuit uses the ACS714 chip of Allegro. This chip is a current isolation type current sensor with a common-mode rejection field effect and is composed of a high-precision low-offset linear Hall sensor.

[0036] As Figure 5 shown, the voltage division follower filter unit includes operational amplifier U3, resistor R11, resistor R12, operational amplifier U4, resistor R13, and capacitor C7. The output terminal of operational amplifier U3 is connected to one end of resistor R12. The other end of resistor R12 is respectively connected to one end of resistor R11 and the positive input terminal of operational amplifier U4. The output terminal of operational amplifier U4 is connected to one end of resistor R13. The other end of resistor R13 is respectively connected to one end of capacitor C7 and the A / D conversion unit. The other end of capacitor C7 is grounded. The other end of resistor R11 is connected to the current signal conditioning circuit. The signal passes through the analog switch and then passes through the voltage division % follower % filter circuit, and then is input into the AD converter. The voltage follower makes the circuit present a high-impedance input and a low-impedance output, improving the load-carrying capacity of the circuit. The chip models of operational amplifier U3 and operational amplifier U4 are AD8031. The maximum sampling current of the ACS714 chip is 5A.

[0037] The chip model of the multi-channel signal switching module is CD4052 / CC4052.

[0038] Among them, the ADE7878 power chip is a high-precision three-phase power measurement IC. The ADE7878 is suitable for measuring active, reactive, and apparent power in various three-wire and four-wire two-three-phase configurations, such as Y-shaped or delta-shaped, etc. Each phase has a system calibration function, namely effective value offset correction, phase calibration, and gain calibration. The CF1, CF2, and CF3 logic outputs can provide a lot of power information: total / fundamental active / reactive power, total apparent power, or current effective value sum.

[0039] The ADE7878 has a waveform sampling register that allows access to all ADC outputs. This device also provides power quality measurements, such as short-term low voltage or high voltage detection, short-term high current changes, line voltage cycle measurement, and the angle between phase voltage and current, etc. Using two serial interfaces SPI and I2C, communication can be carried out with the ADE7878. At the same time, the dedicated high-speed interface and high-speed data acquisition (HSDC) port can be used in conjunction with I2C to access the ADC output and real-time power information. This device also has two interrupt request pins / IRQ0 and / IRQ1, which are used to indicate that an enabled interrupt event has occurred.

[0040] The voltage sampling module is implemented by means of resistor voltage division. A large resistor and a small resistor are connected in series, and the voltage signal across the small resistor is sampled. In this way, an analog voltage in the range of 0 to 500 mV is output at the output terminal VA (VB, VC). This analog voltage signal is input into the ADE7878.

[0041] The sensor of the current sampling module uses a current transformer. The primary side is directly the actual measurement line, and its secondary side output is a current signal (the specific output current magnitude depends on requirements). Therefore, the current sampling is implemented by means of series resistors. Two resistors are connected in series to achieve this, and in this way, an AC voltage signal in the range of 0 to 500 mV can be obtained.

[0042] When collecting multi-channel power quantity signals, it is necessary to timely switch the 4052 to access the analog signal of the ADE7878 chip.

[0043] Multi-channel signal switching module: One power metering chip can collect 4-channel current, power or single-channel current, power, and power quantity data. The key to realizing multi-channel current detection is to switch each channel current signal to access the ADE7878 chip through the CD4052 / CC4052. The CD4052 / CC4052 is a differential 4-channel digital control analog switch, with two binary control input terminals A and B and the INH input, having low on-resistance and very low off-leakage current. These switching circuits have extremely low static power consumption throughout the power supply range, regardless of the logic state of the control signal. The two-bit binary input signal selects one of the 4 pairs of channels, and can connect this input to the output.

[0044] The circuit adopted by this system can realize the collection of multi-channel power quantity data with one power metering chip. And within the rated sampling range of each power quantity data, the accuracy can reach 1%. The circuit is simple, flexible in application, high in accuracy, and low in cost. All technical indicators of the system have met the design requirements, work reliably, and have been put into use, having high application value and being of reference significance for the development of systems such as process monitoring and data collection.

[0045] Only some exemplary embodiments of the present utility model are described above by way of illustration. Undoubtedly, for those of ordinary skill in the art, without departing from the spirit and scope of the present utility model, the described embodiments can be modified in various different ways. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the protection scope of the claims of the present utility model.

Claims

1. A voltage and current detection system with good anti-interference effect, characterized in that: It includes a voltage acquisition module, a current acquisition module, a sensor signal conditioning circuit, a current signal conditioning circuit, a voltage signal conditioning circuit, a multi-channel signal switching module, a voltage-dividing follower filtering circuit, an ADE7878 power chip, a controller module, a display module, a data transmission module, a data storage module, an alarm module, an input setting module, a timing module, an interface module and a power supply module; the power supply module includes a voltage source and an overvoltage protection circuit connected thereto; the output ends of the voltage acquisition module are respectively connected to the input ends of the sensor signal conditioning circuit, the current signal conditioning circuit and the voltage signal conditioning circuit, the output ends of the current acquisition module are respectively connected to the input ends of the sensor signal conditioning circuit, the current signal conditioning circuit and the voltage signal conditioning circuit, the output ends of the sensor signal conditioning circuit, the current signal conditioning circuit and the voltage signal conditioning circuit are connected to the input end of the multi-channel signal switching module, the output end of the multi-channel signal switching module is connected to the input end of the voltage-dividing follower filtering circuit, the output end of the voltage-dividing follower filtering circuit is connected to the input end of the ADE7878 power chip, the output end of the ADE7878 power chip is connected to the input end of the controller module, and the display module, the data transmission module, the data storage module, the alarm module, the input setting module, the timing module, the interface module and the power supply module are respectively connected to the controller module.

2. The voltage and current detection system with good anti-interference effect according to claim 1, characterized in that: The controller module includes a high-stability crystal oscillator module, an FPGA main control module, a USB transmission module, a serial port module, a data processing center, a USB interface, a gigabit network interface and an HDMI interface. The high-stability crystal oscillator module is connected to the FPGA main control module. The FPGA main control module is respectively connected to the data processing center through the SB transmission module and the serial port module. The USB interface, the gigabit network interface and the HDMI interface are respectively connected to the data processing center.

3. A voltage and current detection system with good anti-interference effect according to claim 1, characterized in that: The overvoltage protection circuit includes a reference voltage circuit and a feedback control circuit.

4. A voltage and current detection system with good anti-interference effect according to claim 1, characterized in that: The sensor signal conditioning circuit includes an analog signal input terminal, a resistor R1, a resistor R2, a capacitor C1, and an operational amplifier U1. The analog signal input terminal is respectively connected to one end of the resistor R1 and one end of the resistor R2. The other end of the resistor R2 is connected to one end of the capacitor C1. The other end of the capacitor C1 is respectively connected to the other end of the resistor R1 and the positive input terminal of the operational amplifier U1. The negative input terminal of the operational amplifier U1 is connected to the output terminal of the operational amplifier U1.

5. A voltage and current detection system with good anti-interference effect according to claim 1, characterized in that: The voltage signal conditioning circuit includes a voltage signal input terminal, a resistor R3, a resistor R4, a resistor R5, a capacitor C2, and an operational amplifier U2. The voltage signal input terminal is connected to one end of the resistor R3. The other end of the resistor R3 is respectively connected to one end of the resistor R4 and one end of the resistor R5. The other end of the resistor R5 is connected to one end of the capacitor C2. The other end of the capacitor C2 is respectively connected to the other end of the resistor R4 and the positive input terminal of the operational amplifier U1. The negative input terminal of the operational amplifier U2 is connected to the output terminal of the operational amplifier U2.

6. The voltage and current detection system with good anti-interference effect according to claim 1, characterized in that: The current signal conditioning circuit uses the ACS714 chip of Allegro. This chip is a current isolation type current sensor with a common mode rejection field effect and is composed of a high-precision low-offset linear Hall sensor.

7. A voltage and current detection system with good anti-interference effect according to claim 1, characterized in that: The voltage division and follower filtering unit includes operational amplifier U3, resistor R11, resistor R12, operational amplifier U4, resistor R13, and capacitor C7. The output terminal of operational amplifier U3 is connected to one end of resistor R12, and the other end of resistor R12 is respectively connected to one end of resistor R11 and the positive input terminal of operational amplifier U4. The output terminal of operational amplifier U4 is connected to one end of resistor R13, and the other end of resistor R13 is respectively connected to one end of capacitor C7 and the A / D conversion unit. The other end of capacitor C7 is grounded, and the other end of resistor R11 is connected to the current signal conditioning circuit.

8. An anti-interference voltage and current detection system as claimed in claim 1, characterized in that: The chip model of the multi-channel signal switching module is CD4052 / CC4052.

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