A New Digital Three-phase Intelligent Electric Measurement Transmitter

Abstract

The utility model provides a new type of digital three-phase intelligent electrical measurement transmitter, including a signal parallel input detection module, a signal synchronous conversion module, a main controller module, a transmitter isolation output module, and a power supply module. The utility model realizes three-phase data synchronous measurement in a strict sense through one instrument; the transmitter isolation outputs DC‑5V‑‑+5V standard signals, and supports the transmission isolation output of serial RS485 bus digital signals, supports long-distance transmission and supports cascade transmission of multiple transmitters. The module also supports RS232 serial interface communication; supports event input monitoring and output control interface circuits; has a wide power supply range, supports DC or AC power supply, and ensures continuous and stable operation of the module under complex working conditions. The primary and secondary isolation insulation voltages of the transformer are high, and the secondary power supplies are isolated from each other, and the signals are not interfered with each other during detection and conversion, while ensuring user safety and no interference with other equipment.

Description

Technical Field

[0001] The utility model relates to the technical field of electrical parameter measuring instruments, in particular to a novel digital three-phase intelligent electrical measuring transmitter. Background Art

[0002] Traditional three-phase electrical measurement transmitters can only detect and measure three voltages or three currents, and transmit and output three analog standard signals. They cannot measure other electrical parameter data derived from each phase or between the three phases. They have single functions and a narrow application range and cannot meet the current testing needs of three-phase power, motors and electronic automation systems.

[0003] If three digital single-phase intelligent electricity transmitters are used to measure a three-phase system, although the measurement and transmission of various electrical parameters of each phase signal in the three-phase system can be solved, it is still impossible to accurately obtain the measurement data of various electrical parameters derived from the three-phase signals. For example, it is impossible to achieve real-time, synchronous and parallel measurement of three-phase phase voltage and line voltage, and it is impossible to accurately measure the total active power, total reactive power, total apparent power, total power factor, three-phase phase sequence, phase angle, positive sequence component, negative sequence component, zero sequence component, imbalance, etc. of the three-phase system.

[0004] The root cause is that each single-phase power transmitter module works independently, and independently controls the acquisition, measurement and transmission output of the input signal, which cannot achieve real-time synchronous measurement. Even if three single-phase intelligent power transmitters with data synchronization function are cascaded, this structure is complex, costly, and cannot achieve strict synchronization.

[0005] The above problems are technical problems that need to be solved urgently for three-phase electrical measurement transmitters. Utility Model Content

[0006] In order to solve the above problems, the utility model provides a new digital three-phase intelligent electrical measurement transmitter, including a signal parallel input detection module, a signal synchronous conversion module, a main controller module, a transmission isolation output module, and a power supply module;

[0007] The signal parallel input detection module includes 3-way voltage signal parallel input detection circuit and 3-way current signal parallel input detection circuit, which are used to linearly convert high voltage and high current electrical signals into low voltage mV analog signals that can be directly processed by the transmitter;

[0008] The signal synchronization conversion module uses an integrated circuit chip to convert the mV level signal generated by the signal input synchronization detection circuit and the built-in reference voltage signal of the chip in real time, and the digital signal after low-pass filtering is transmitted to the main controller module as the final instantaneous value;

[0009] The main controller module includes a three-phase transmitter main controller minimum system circuit, a human-machine auxiliary interaction interface circuit, and an event input monitoring and output control interface circuit;

[0010] The transmission isolation output module includes an analog transmission isolation output interface circuit and a UART communication transmission isolation output interface circuit;

[0011] The power supply module includes a three-phase transmitter power supply isolation interface circuit.

[0012] Optionally, the signal synchronous conversion module adopts the integrated circuit chip ATM90E36A, which integrates 7 differential signal conditioning and digital low-pass filtering circuits, and also integrates 7 synchronous sampling high-precision and high-performance second-order Sigma-DeltaAD analog-to-digital conversion circuits. Among them, 6 AD real-time conversion signals are input into the mV-level signal generated by the synchronous detection circuit, and another 1 AD real-time conversion is the built-in reference voltage signal of the ATM90E36A chip. The digital signal processed by the low-pass filtering circuit is transmitted to the main controller as the final instantaneous value, generating a total of 56,000 instantaneous value data per second.

[0013] Optionally, the three-phase transmitter main controller minimum system circuit uses a 32-bit single-chip microcomputer chip STM32F103RFT6 as the transmitter main controller.

[0014] Optionally, the human-machine assisted interaction interface circuit is directly connected to the transmitter main controller of the minimum system circuit of the three-phase transmitter main controller through an IO port, and a dynamic scanning IO port is used for display and key input.

[0015] Optionally, the event input monitoring and output control interface circuit uses a photoelectric coupler HCPL2631S to isolate and monitor digital signal input and isolate and output real-time digital signals.

[0016] Optionally, each output of the analog quantity transmitter isolation output interface circuit adopts a DAC8311 digital-to-analog conversion chip as the DA master control, with a conversion accuracy of 14 bits and an output voltage stabilization time of 10us. The transmitter main controller of the minimum system circuit of the three-phase transmitter main controller uses a 3-wire SPI interface to connect with three DAC8311s through two magnetoelectric couplers SI8440, and performs real-time 3-way data digital-to-analog DA conversion, and cooperates with three OPA211s to output DC-5V--+5V standard analog signals.

[0017] Optionally, the UART communication transmitter isolation output interface circuit uses a serial interface to perform UART isolation communication through the transmitter main controller of the three-phase transmitter main controller minimum system circuit, and supports RS232 or RS485 serial bus, wherein the RS232 bus uses a MAX232 chip as the transceiver of the digital signal communication interface, and the RS485 bus uses a MAX487 chip as the transceiver of the digital signal communication interface, thereby realizing intelligent interactive output of various data of the transmitter, and can also choose to actively send data in one direction.

[0018] Optionally, the three-phase transmitter power supply isolation interface circuit uses a TNY277 power management chip as a main control chip, and the TNY277 power management chip integrates a 700V power MOSFET, an oscillator, a high-voltage switching current source, a current limiting circuit, and a chip temperature overheating shutdown protection circuit;

[0019] The power input range of the switching power supply is AC85-265V or DC100-300V. The module uses a high-frequency transformer to isolate and output 4 DC regulated voltage sources:

[0020] The first power supply M5V: uses the voltage regulator LM1117 / 3.3V to stabilize the voltage to 3.3V, and together with it, it supplies power to the transmitter main controller module;

[0021] The second power supply RS5V: used for UART communication transmission isolation output interface power supply;

[0022] The third power supply A+7.5V and the fourth power supply A-7.5V: use the voltage regulator LM1117 / 5.0V to stabilize the voltage to 5.0V, and together supply power to the analog quantity transmitter isolation output interface;

[0023] Among them, the three groups of power supply No. I, power supply No. II, and power supply No. III / IV are isolated from each other, and the insulation withstand voltage is 2500V for 1 minute.

[0024] Optionally, the minimum system circuit of the main controller of the three-phase transmitter uses the internal FLASH of the main controller to store various operating parameters, and uses the FM24C256 ferroelectric memory to store data that needs to be saved frequently.

[0025] The beneficial effects of the utility model compared with the prior art are:

[0026] 1: This transmitter realizes the test needs of real-time response, data diversification, intelligent functions and integration of various data of the three-phase system measured by one instrument.

[0027] Through the scheme of real-time acquisition of 6-way signals, synchronous conversion of 6-way AD, parallel measurement and processing of 6-way instantaneous value data, and real-time calculation of various electrical quantity data, it is possible to measure not only the three-phase input voltage and current data of three-phase equipment, but also other electrical parameter data derived from each phase and between three phases, such as: line voltage data in three-phase four-wire system, phase voltage data in three-phase three-wire system, accurate measurement of fundamental wave and full-wave total active power / total reactive power / total apparent power / total power factor, three-phase phase sequence, voltage phase angle, positive sequence component, negative sequence component, voltage imbalance, current imbalance, etc. in three-phase system.

[0028] Through highly integrated intelligent design, the instrument structure is simplified, the instrument cost for measuring three-phase systems is reduced, and most importantly, strict three-phase data synchronous measurement is achieved.

[0029] 2: This transmitter not only transmits isolated output DC-5V--+5V standard signal, but also supports transmitting isolated output serial RS485 bus digital signal, supports long-distance transmission and supports cascade transmission of multiple transmitters. The module also supports RS232 serial interface communication.

[0030] 3: This transmitter supports event input monitoring and output control interface circuits.

[0031] The main controller performs corresponding processing according to the monitored digital input status events of the switch quantity, such as turning on or off the judgment of electric quantity data exceeding the limit or the capture of extreme value data. The main controller executes the output function for the set event and cooperates with the whole automation system to perform on-site response or closed-loop control, which makes the industry application of three-phase electric measurement transmitter more intelligent and meets the new requirements of industry development.

[0032] 4: This transmitter has a wide power supply range and supports DC or AC power supply. It ensures continuous and stable operation of the module under complex working conditions. The primary and secondary isolation insulation voltage of the transformer is high, and the secondary power supplies are isolated from each other. There is no interference during signal detection and conversion, which ensures user safety and no interference to other equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0034] Figure 1 It is a structural block diagram of the utility model;

[0035] Figure 2This is a schematic diagram of the principle of a three-way voltage signal parallel input detection circuit of the utility model;

[0036] Figure 3 This is a schematic diagram of the principle of a three-way current signal parallel input detection circuit of the utility model;

[0037] Figure 4 This is a schematic diagram of the principle of the signal synchronization conversion module of the utility model;

[0038] Figure 5 This is a schematic diagram of the minimum system circuit of the main controller of the three-phase transmitter of the utility model;

[0039] Figure 6 This is a schematic diagram of the principle of the analog quantity transmission isolation output interface circuit of the utility model;

[0040] Figure 7 This is a schematic diagram of the principle of the UART communication transmission isolation output interface circuit of the utility model;

[0041] Figure 8 The utility model is a schematic diagram of the principle of the three-phase transmitter power supply isolation interface circuit. DETAILED DESCRIPTION

[0042] The embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although certain embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as being limited to the embodiments described herein. Instead, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the drawings and embodiments of the present invention are only for exemplary purposes and are not intended to limit the scope of protection of the present invention.

[0043] like Figure 1 As shown, a novel digital three-phase intelligent electrical measurement transmitter provided by an embodiment of the present disclosure includes a signal parallel input detection module, a signal synchronous conversion module, a main controller module, a transmission isolation output module, and a power supply module;

[0044] The signal parallel input detection module includes 3-way voltage signal parallel input detection circuit and 3-way current signal parallel input detection circuit, which are used to linearly convert high voltage and high current electrical signals into low voltage mV analog signals that can be directly processed by the transmitter;

[0045] The signal synchronization conversion module uses an integrated circuit chip to convert the mV level signal generated by the signal input synchronization detection circuit and the built-in reference voltage signal of the chip in real time, and the digital signal after low-pass filtering is transmitted to the main controller module as the final instantaneous value;

[0046] The main controller module includes a three-phase transmitter main controller minimum system circuit, a human-machine auxiliary interaction interface circuit, and an event input monitoring and output control interface circuit;

[0047] The transmission isolation output module includes an analog transmission isolation output interface circuit and a UART communication transmission isolation output interface circuit;

[0048] The power supply module includes a three-phase transmitter power supply isolation interface circuit.

[0049] 1. Signal parallel input detection module

[0050] refer to Figure 2 and Figure 3 , 3-way voltage signal parallel input detection circuit and 3-way current signal parallel input detection circuit: parallel and synchronous detection of the voltage and current signals in the three-phase load under test; the signal input synchronous detection circuit is used to linearly convert high voltage and high current electrical signals into low voltage mV level analog signals that can be directly processed by the transmitter. This detection circuit does not change the synchronization relationship between the original input signals, but only linearly changes the amplitude of the signal.

[0051] 2. Signal Synchronous Conversion Module

[0052] refer to Figure 4 , using Atmel's three-phase highly integrated power-specific integrated circuit ATM90E36A. The chip not only integrates 7-way differential signal conditioning and digital low-pass filtering circuits, but also integrates 7-way synchronous sampling high-precision and high-performance second-order Sigma-DeltaAD analog-to-digital conversion circuits. Among them, 6-way AD real-time conversion circuit ① generates mV-level signals, and the other 1-way AD real-time conversion ATM90E36A chip built-in reference voltage signal.

[0053] The 3-way voltage and 3-way current signals are processed by the differential amplifier circuit, which not only suppresses the common-mode noise superimposed on the effective signal, but also can select 1 / 2 / 4 times PGA amplification for the input signal. The amplified signal is synchronously input into the 2nd-order Delta-SigmaAD analog-to-digital conversion circuit, synchronously converted into 6-way 24-bit high-precision digital signals, and synchronously performs digital low-pass filtering to filter out high-order harmonics and ripple noise of 2500Hz and above in the signal. The digital signal processed by the low-pass filter circuit is transmitted to the main controller as the final instantaneous value, generating a total of 56,000 instantaneous value data per second.

[0054] The ATM90E36A chip integrates 3-way zero-crossing signal synchronous output function, and can configure any 3-way voltage and 3-way current signals, which not only simplifies the circuit and reduces the cost, but also improves the functional applicability.

[0055] 3. Main Controller Module

[0056] 1: Reference Figure 5 ,The minimum system circuit of the three-phase transmitter main controller: The 32-bit MCU with integrated ArmCortex-M3 core from STMicroelectronics is used as the main controller of the transmitter. The chip model is STM32F103RFT6, with an operating frequency of 72MHz, integrated with 768K on-chip erasable FLASH and 96K on-chip SRAM, which meets the main control requirements of the transmitter while taking into account the cost of the entire solution.

[0057] The periodic zero-crossing pulse signal output by the signal synchronization conversion module obtains 6-channel signal periodic data through the capture interrupt of the timer of the minimum system circuit of the three-phase transmitter main controller, thereby improving the accuracy of obtaining the complete cycle of the AC signal. The 7-channel 24-bit high-precision digital signal output by the signal synchronization conversion module is input into the minimum system circuit transmitter main controller of the three-phase transmitter main controller in real time through the 4-wire SPI high-speed serial bus, capturing 56,000 instantaneous value data per second.

[0058] The voltage reference value of the chip is easily affected by power supply ripple noise and signal interference. The reference value of the chip fluctuates, affecting the AD conversion performance of the signal synchronization conversion module. By obtaining the instantaneous value change of the chip reference signal through the minimum system circuit of the three-phase transmitter main controller, the instantaneous value data of the other 6 electrical signals can be dynamically compensated in real time, minimizing the impact of the fluctuation of the chip reference value on the data.

[0059] The main controller obtains the true effective value, rectified average value, waveform factor, peak and trough, frequency, harmonics and other electrical data of the 6 electrical signals by analyzing and calculating these instantaneous values.

[0060] Since the 6-way electrical signal is converted into digital signal synchronously from terminal input, the synchronous electrical quantity data between the 6-way electrical signal can also be obtained through calculation, including the phase difference data between voltages, between currents, and between voltage and current, which is used to calculate the three-phase phase sequence, phase angle, positive sequence component, negative sequence component, zero sequence component, voltage unbalance, current unbalance value and various fundamental power and electrical quantity data.

[0061] Various important data of the transmitter, including various operating parameters, event status, etc., are stored in the FLASH inside the main control. For data that needs to be saved frequently, such as various types of electrical energy data, Ramtron's FM24C256 ferroelectric memory is used for storage, which ensures the reliability of data storage and meets the requirements of the total number of frequent erase and write times.

[0062] 2: Human-machine assisted interaction interface circuit: The transmitter main controller of the minimum system circuit of the three-phase transmitter main controller is directly connected to the IO port, and the dynamic scanning IO port is used for display and key input. The operation and event status and working mode of the main controller can be viewed, and some operation parameters can be set, such as communication address, baud rate, etc.

[0063] 3: Event input monitoring and output control interface circuit: The transmitter main controller uses the photocoupler HCPL2631S to isolate and monitor the digital signal input, obtain the switch state and pulse period of the digital signal, and the main controller responds and processes, and transmits this state to the upper device through the UART communication transmission isolation output interface circuit. The transmitter supports the output of the limit judgment event of the electric quantity data, responds to the UART command execution output, and supports the output of the square wave pulse signal for electric energy measurement. The transmitter main controller uses the photocoupler HCPL2631S to isolate and output the real-time digital signal.

[0064] 4. Transmitter isolation output module

[0065] 1: Reference Figure 6 , Analog quantity transmitter isolation output interface circuit: Each output uses Texas Instruments' DAC8311 digital-to-analog conversion chip as the DA master, with a conversion accuracy of 14 bits and an output voltage stabilization time of 10us. The high-speed and high-bit-width conversion of DAC8311 ensures the rapid response of the transmission output. The transmitter main controller of the minimum system circuit of the three-phase transmitter main controller uses a 3-wire SPI interface to connect with 3 DAC8311 through 2 magnetoelectric couplers SI8440, and performs 3-way data digital-to-analog DA conversion in real time, and cooperates with 3 OPA211 to output DC-5V--+5V standard analog signals.

[0066] 2: Reference Figure 7 , UART communication transmitter isolation output interface circuit: The transmitter main controller of the three-phase transmitter main controller minimum system circuit uses the serial interface UART isolation communication, supports RS232 or RS485 serial bus, among which the RS232 bus uses MAXIM's MAX232 chip as the transceiver of the digital signal communication interface, and the RS485 bus uses MAXIM's MAX487 chip as the transceiver of the digital signal communication interface to realize the intelligent interactive output of various data of the transmitter. At the same time, it can choose to actively send data in one direction to meet some working conditions with high real-time requirements.

[0067] 5. Power supply module

[0068] refer to Figure 8, three-phase transmitter power supply isolation interface circuit: PowerIntegrations' TNY277 power management chip is used as the main control chip of the flyback switching power supply circuit. TNY277 integrates a 700V power MOSFET, oscillator, high-voltage switching current source, current limiting and chip temperature overheating shutdown protection circuit.

[0069] The power input range of the switching power supply is AC85-265V or DC100-300V. The module uses a high-frequency transformer to isolate and output 4 DC regulated voltage sources:

[0070] The first power supply M5V: uses the voltage regulator LM1117 / 3.3V to stabilize the voltage to 3.3V, and together with it, it supplies power to the transmitter main controller module;

[0071] The second power supply RS5V: used for UART communication transmission isolation output interface power supply;

[0072] The third power supply A+7.5V and the fourth power supply A-7.5V: use the voltage regulator LM1117 / 5.0V to stabilize the voltage to 5.0V, and together supply power to the analog quantity transmitter isolation output interface;

[0073] Among them, the three groups of power supply I, power supply II, and power supply III / IV are isolated from each other, and the insulation withstand voltage is 2500V for 1 minute, which meets the voltage withstand safety requirements of primary instruments in complex industrial sites and meets the working power supply needs of each module circuit of this three-phase transmitter.

[0074] The exemplary implementation of the satellite solar array shunt power storage and conversion circuit proposed in the utility model is described in detail above with reference to the preferred embodiments. However, those skilled in the art will appreciate that, without departing from the concept of the utility model, various modifications and alterations may be made to the above-mentioned specific embodiments, and various technical features and structures proposed in the utility model may be combined in various ways without exceeding the protection scope of the utility model, which is determined by the appended claims.

Claims

1. A new type of digital three-phase intelligent electrical measurement transmitter, characterized in that: It includes a signal parallel input detection module, a signal synchronous conversion module, a main controller module, a transmission isolation output module, and a power supply module; The signal parallel input detection module includes 3-way voltage signal parallel input detection circuit and 3-way current signal parallel input detection circuit, which are used to linearly convert high voltage and high current electrical signals into low voltage mV analog signals that can be directly processed by the transmitter; The signal synchronous conversion module uses an integrated circuit chip to convert the mV level signal generated by the signal input synchronous detection circuit and the built-in reference voltage signal of the chip in real time, and the digital signal after low-pass filtering is transmitted to the main controller module as the final instantaneous value; The main controller module includes a three-phase transmitter main controller minimum system circuit, a human-machine auxiliary interaction interface circuit, and an event input monitoring and output control interface circuit; The transmission isolation output module includes an analog transmission isolation output interface circuit and a UART communication transmission isolation output interface circuit; The power supply module includes a three-phase transmitter power supply isolation interface circuit.

2. A novel digital three-phase intelligent electrical measurement transmitter according to claim 1, characterized in that: The signal synchronous conversion module adopts the integrated circuit chip ATM90E36A, which integrates 7 differential signal conditioning and digital low-pass filtering circuits, and also integrates 7 synchronous sampling high-precision and high-performance second-order Sigma-DeltaAD analog-to-digital conversion circuits. Among them, 6 AD real-time conversion signals are input into the mV-level signal generated by the synchronous detection circuit, and the other 1 AD real-time conversion is the built-in reference voltage signal of the ATM90E36A chip. The digital signal processed by the low-pass filtering circuit is transmitted to the main controller as the final instantaneous value, and a total of 56,000 instantaneous value data are generated per second.

3. A novel digital three-phase intelligent electrical measurement transmitter according to claim 1, characterized in that: The three-phase transmitter main controller minimum system circuit adopts a 32-bit single-chip microcomputer chip STM32F103RFT6 as the transmitter main controller.

4. A novel digital three-phase intelligent electrical measurement transmitter according to claim 1, characterized in that: The human-machine assisted interactive interface circuit is directly connected to the transmitter main controller of the minimum system circuit of the three-phase transmitter main controller through an IO port, and a dynamic scanning IO port is used for display and key input.

5. A novel digital three-phase intelligent electrical measurement transmitter according to claim 1, characterized in that: The event input monitoring and output control interface circuit adopts a photoelectric coupler HCPL2631S to isolate and monitor digital signal input and isolate and output real-time digital signals.

6. A novel digital three-phase intelligent electrical measurement transmitter according to claim 1, characterized in that: Each output of the analog quantity transmitter isolation output interface circuit adopts DAC8311 digital-to-analog conversion chip as DA master control, with conversion accuracy of 14 bits and output voltage stabilization time of 10us. The transmitter main controller of the minimum system circuit of the three-phase transmitter main controller uses a 3-wire SPI interface to connect with three DAC8311 chips through two magnetoelectric couplers SI8440, performs real-time 3-way data digital-to-analog DA conversion, and cooperates with three OPA211 chips to output DC-5V--+5V standard analog signals.

7. A novel digital three-phase intelligent electrical measurement transmitter according to claim 1, characterized in that: The UART communication transmission isolation output interface circuit uses a serial interface to perform UART isolation communication through the transmitter main controller of the minimum system circuit of the three-phase transmitter main controller, supports RS232 or RS485 serial bus, wherein the RS232 bus uses a MAX232 chip as the transceiver of the digital signal communication interface, and the RS485 bus uses a MAX487 chip as the transceiver of the digital signal communication interface, thereby realizing the intelligent interactive output of various data of the transmitter, and can select unidirectional active data transmission.

8. A novel digital three-phase intelligent electrical measurement transmitter according to claim 1, characterized in that: The three-phase transmitter power supply isolation interface circuit adopts the TNY277 power management chip as the main control chip. The TNY277 power management chip integrates a 700V power MOSFET, an oscillator, a high-voltage switch current source, a current limiting circuit and a chip temperature overheating shutdown protection circuit; The power input range of the switching power supply is AC85-265V or DC100-300V. The module uses a high-frequency transformer to isolate and output 4 DC regulated voltage sources: The first power supply M5V: uses the voltage regulator LM1117 / 3.3V to stabilize the voltage to 3.3V, and together with it, it supplies power to the transmitter main controller module; The second power supply RS5V: used for UART communication transmission isolation output interface power supply; The third power supply A+7.5V and the fourth power supply A-7.5V: use the voltage regulator LM1117 / 5.0V to stabilize the voltage to 5.0V, and together supply power to the analog quantity transmitter isolation output interface; Among them, the three groups of power supply No. I, power supply No. II, and power supply No. III / IV are isolated from each other, and the insulation withstand voltage is 2500V for 1 minute.

9. A novel digital three-phase intelligent electrical measurement transmitter according to claim 1, characterized in that: The minimum system circuit of the main controller of the three-phase transmitter adopts the internal FLASH of the main controller to store various operating parameters, and adopts the FM24C256 ferroelectric memory to store data that needs to be frequently saved.

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