CN-121978393-A - Three-phase electric parameter measurement system and method based on double metering chips

CN121978393ACN 121978393 ACN121978393 ACN 121978393ACN-121978393-A

Abstract

The invention discloses a three-phase electric parameter measurement system and method based on double metering chips, and belongs to the technical field of electric power measurement. The technical problem to be solved is that the existing three-measuring chip scheme for three-phase electrical parameter measurement has the problems of high hardware cost, difficult compromise between calculation precision and real-time performance and high requirement on the calculation capacity of a processor. The technical scheme is characterized in that two high-precision metering chips are adopted to collect B, C phase voltage and current instantaneous values respectively, a synchronous control module, a voltage calculation module and a current calculation module are arranged in a main controller, the synchronous control module realizes double-phase data synchronization through a lightweight state machine and a synchronous marker bit, the voltage calculation module adopts a virtual ground algorithm to analyze and solve a reference ground potential F point coordinate so as to calculate A phase voltage, the current calculation module obtains A phase current based on vector algorithm inversion, and finally complete measurement of three-phase electric parameters is realized.

Inventors

ZHAO ZEYU
WANG CHENGZHI
CHEN TAO
SHI WEIGUO

Assignees

浙江瑞银电子有限公司

Dates

Publication Date: 20260505
Application Date: 20260408

Claims (10)

1. The three-phase electric parameter measurement system based on the double metering chips is characterized by comprising a main controller and a high-precision metering chip, wherein the high-precision metering chip comprises a first chip and a second chip; the first chip is used for collecting the voltage instantaneous value and the current instantaneous value of the B phase in the three-phase power, the second chip is used for collecting the voltage instantaneous value and the current instantaneous value of the C phase in the three-phase power, and the first chip and the second chip are both in communication connection and power supply connection with the main controller; the synchronous control module tracks the ready state of B phase and C phase acquisition data through a lightweight state machine and a synchronous zone bit, polls the synchronous zone bit and triggers the voltage calculation module and the current calculation module to start only when the B phase and the C phase acquisition data are ready; the voltage calculation module adopts a virtual ground algorithm to construct two intersecting circle models based on an AFC three point and a BFC three point, and utilizes a three-phase system to realize ideal balance state The characteristic analysis of the phase A is used for solving the F point coordinate of the reference ground potential, and the phase voltage and the line voltage of the phase A are obtained through calculation; The current calculation module adopts a vector algorithm, judges the relative relation between B phase voltage and C phase voltage and current through a voltage-current angle, determines corresponding current vectors, and then performs inversion calculation to obtain phase current and line current of the A phase.
2. The dual metering chip based three phase electrical parameter measurement system of claim 1, wherein the workflow of the synchronization control module comprises: The method comprises the steps of finishing instantaneous data acquisition of a B phase and a C phase in a fixed period, setting corresponding synchronous flag bits immediately after the acquisition is finished, enabling a lightweight state machine to comprise a plurality of working states, realizing state switching according to the states of the synchronous flag bits and the data acquisition condition, triggering the metering flow of an A phase electric parameter, and executing a preset exception handling strategy when the condition that the acquisition data of a certain phase is ready is not detected in a period exceeding a set time.
3. The dual-metering-chip-based three-phase electrical parameter measurement system according to claim 2, wherein a polling period of the synchronization control module for the synchronization flag is consistent with the fixed period; And the synchronous flag bit is a variable of the uint8_t type, a value of 1 indicates that the corresponding phase acquired data is ready, a value of 0 indicates that the corresponding phase acquired data is not ready, and the B phase and the C phase acquired data are judged to be ready when the two-phase synchronous flag bits are both 1.
4. The dual-metering-chip-based three-phase electrical parameter measurement system according to claim 3, wherein the working states of the lightweight state machine include an IDLE state, a GETDATA state and a RESET state, the IDLE state is a standby state between two times of data acquisition, the GETDATA state is a working state that a timer of the fixed period is timed to arrive, a main controller sends data requests to two high-precision metering chips, and the RESET state is an abnormal recovery state entered after data acquisition fails in three continuous GETDATA states; The preset exception handling strategy is to reset the communication serial port of the main controller and the chip, and reinitiate the data acquisition request after resetting.
5. The dual-metering-chip-based three-phase electrical parameter measurement system of claim 1, wherein the virtual ground algorithm performing step comprises: establishing a two-dimensional coordinate system, defining endpoint coordinates of B-phase and C-phase voltages and a voltage data format based on the endpoint coordinates Is derived from the characteristics of (a) On the AB mid-vertical line Determining the center of circle Coordinates and radius of (a) Deriving the center of circle by the same theory Coordinates and radius of (a) ; Center of circle 、 Resolving and solving the F point coordinate by combining the two corresponding round equations and the geometric constraint condition; And if the condition that two circles have no intersection points, two intersection points or a three-phase system is unbalanced, executing a preset adjustment strategy.
6. The dual-metering-chip-based three-phase electric parameter measurement system according to claim 5, wherein the two-dimensional coordinate system uses an initial datum point of a three-phase electric virtual reference ground as an origin, uses a positive direction of a B-phase voltage vector as an X-axis and uses a direction vertical to the X-axis as a Y-axis, the voltage data format is a floating point type instantaneous value, the unit is V, and the two-circle equation is: Wherein, the Is that The coordinates of the two points of the coordinate system, Is that And solving the F point coordinate by eliminating the quadratic term of the two-circle equation by a primordial elimination method.
7. The dual-metering-chip-based three-phase electrical parameter measurement system of claim 5, wherein the preset adjustment strategy of the virtual ground algorithm is: if there is no intersection point or two intersection points, the two circles are aligned with the center of a circle 、 And if the three-phase system is unbalanced, calling an effective F point coordinate mean value acquired by the latest preset time as a compensation value, and combining the current calculation result to obtain the effective F point coordinate.
8. The dual-metering-chip-based three-phase electrical parameter measurement system of claim 1, wherein the performing step of the vector algorithm comprises: By an active power formula Reactive power formula Calculating to obtain the pressure flow angle of B phase and C phase ; Taking the voltage vector of B phase and C phase in the two-dimensional coordinate system as a reference, and according to the pressure flow angle Judging the phase relation of the leading or lagging of the current vector relative to the voltage vector, and further determining the current vectors of the B phase and the C phase; Based on the principle that the sum of three-phase current vectors is 0, the A-phase current vector is obtained through formula inversion calculation, and the specific formula is as follows: and mapping the A-phase current vector to the two-dimensional coordinate system, and obtaining the actual size of the A-phase current through vector coordinate analysis and calculation.
9. The three-phase electrical parameter measurement system based on the double metering chips of claim 8, wherein the actual magnitude of the a-phase current is calculated by the following specific formula: Wherein, the Is the coordinate value of the current vector in a two-dimensional coordinate system.
10. The three-phase electric parameter measurement system based on the double metering chips as claimed in claim 1, wherein the communication interface type between the first chip, the second chip and the main controller is UART, the communication protocol adopts the common metering chip protocol, and the power supply connection between the first chip, the second chip and the main controller is direct current power supply mode.

Description

Three-phase electric parameter measurement system and method based on double metering chips Technical Field The invention belongs to the technical field of electric power measurement, and particularly relates to a three-phase electric parameter measurement system and method based on double metering chips. Background In the existing three-phase electric energy metering technology, a three-metering chip scheme is adopted in the main stream, namely, three independent metering chips are used for respectively and correspondingly measuring the voltage and current parameters of three-phase electric energy. However, the existing three-meter chip scheme has the main defects that: (1) The hardware cost is high, and the three-meter chip scheme directly leads to the multiple increase of the material cost of the core hardware. Meanwhile, the multi-chip scheme needs more peripheral circuits (such as crystal oscillator, power management, isolated communication and the like), so that the overall system cost and the physical space occupation are further improved. (2) The calculation precision and the real-time performance are difficult to be compatible, and the existing three-measurement scheme always faces the inherent contradiction between the calculation precision and the real-time performance of the system when processing complex algorithms such as virtual ground calculation and the like. (3) The method has high requirement on the computing capacity of the processor, ensures the real-time performance of the collection of the three metering chips, and has extremely high requirements on the main frequency and the memory resource of the processor due to the complex computing task. In view of this, the present invention has been made. Disclosure of Invention In order to solve the technical problems in the prior art, the invention provides a three-phase electric parameter measurement system and method based on a double metering chip, and solves the technical problems that the existing three-phase electric parameter measurement scheme of the three metering chip is high in hardware cost, difficult to consider both calculation accuracy and real-time performance and high in requirement on the calculation capacity of a processor. In order to achieve the above purpose, the technical scheme of the invention is as follows: A three-phase electric parameter measurement system based on double metering chips comprises a main controller and a high-precision metering chip, wherein the high-precision metering chip comprises a first chip and a second chip; the first chip is used for collecting the voltage instantaneous value and the current instantaneous value of the B phase in the three-phase power, the second chip is used for collecting the voltage instantaneous value and the current instantaneous value of the C phase in the three-phase power, and the first chip and the second chip are both in communication connection and power supply connection with the main controller; the synchronous control module tracks the ready state of B phase and C phase acquisition data through a lightweight state machine and a synchronous zone bit, polls the synchronous zone bit and triggers the voltage calculation module and the current calculation module to start only when the B phase and the C phase acquisition data are ready; the voltage calculation module adopts a virtual ground algorithm to construct two intersecting circle models based on an AFC three point and a BFC three point, and utilizes a three-phase system to realize ideal balance state The characteristic analysis of the phase A is used for solving the F point coordinate of the reference ground potential, and the phase voltage and the line voltage of the phase A are obtained through calculation; The current calculation module adopts a vector algorithm, judges the relative relation between B phase voltage and C phase voltage and current through a voltage-current angle, determines corresponding current vectors, and then performs inversion calculation to obtain phase current and line current of the A phase. Further, the workflow of the synchronization control module includes: The method comprises the steps of finishing instantaneous data acquisition of a B phase and a C phase in a fixed period, setting corresponding synchronous flag bits immediately after the acquisition is finished, enabling a lightweight state machine to comprise a plurality of working states, realizing state switching according to the states of the synchronous flag bits and the data acquisition condition, triggering the metering flow of an A phase electric parameter, and executing a preset exception handling strategy when the condition that the acquisition data of a certain phase is ready is not detected in a period exceeding a set time. Furthermore, the polling period of the synchronous control module to the synchronous zone bit is consistent with the fixed period; And the synchronous flag bit is a variable of the uint8_t type, a