An intelligent electric energy meter based on a RISC-V-M4 core MCU

Abstract

The application is suitable for the technical field of electric power measuring equipment, and relates to an intelligent electric energy meter based on a RISC-V-M4 kernel MCU, which comprises a core control module, a high-precision metering module, a multi-protocol communication module, a dynamic load monitoring module, a low-power consumption management unit and a storage and display module. The application solves the problems of insufficient computing power, single communication protocol, lack of load monitoring, insufficient power consumption control and limited metering precision of the traditional electric energy meter, improves the intelligent level and operation stability of the electric energy meter, and is suitable for industrial power distribution, residential power consumption and other scene electric power metering.

Description

Technical Field

[0001] This invention belongs to the field of power measurement equipment technology, and in particular relates to a smart energy meter based on a RISC-V-M4 core MCU. Background Technology

[0002] With the advancement of smart grid construction, electricity meters need to possess core capabilities such as high-precision metering, multi-dimensional data acquisition, remote communication, and low-power operation. Existing electricity meters mostly use M0 core MCUs, which have the following drawbacks:

[0003] Insufficient computing power: Lacking DSP (Digital Signal Processor) and FPU (Floating Point Unit), it is difficult to efficiently process complex algorithms such as harmonic analysis and reactive power calculation, and the metering accuracy is limited to level 1;

[0004] Limited communication protocol: It only supports RS485 or narrowband IoT single communication mode, which cannot adapt to the "wired + wireless" dual-mode communication requirements of smart grid;

[0005] Lack of load monitoring: The lack of real-time monitoring for impact loads and unbalanced loads can easily lead to increased metering errors or equipment damage.

[0006] Insufficient power consumption control: Traditional MCUs consume a lot of power when multitasking in parallel, which cannot meet the long standby requirements of energy meters.

[0007] Patent application CN116319573A discloses a communication method for a dual-mode module energy meter in a power grid. The dual-mode module energy meter establishes multiple transmission channels between the dual-mode module and a control master station. The communication method includes: monitoring the transmission status of the multiple transmission channels; if the transmission status of the current transmission channel communicating with the control master station is abnormal, determining the transmission channel with a normal transmission status from the remaining channels (excluding the current one); obtaining the transmission delay of the normal transmission channel, and selecting a primary decision channel based on the transmission delay; and transmitting data through the primary decision channel. This patent application primarily addresses the problem of the single communication protocol in existing energy meters, but does not provide relevant technical solutions for other shortcomings of existing energy meters.

[0008] Therefore, it is imperative to address the problems of insufficient computing power, limited communication protocols, lack of load monitoring, inadequate power consumption control, and limited metering accuracy in traditional electricity meters. Summary of the Invention

[0009] To address the shortcomings of existing technologies, the purpose of this invention is to provide a smart energy meter based on a RISC-V-M4 core MCU, in order to solve the problems of insufficient computing power, single communication protocol, lack of load monitoring, insufficient power consumption control, and limited metering accuracy in existing traditional energy meters.

[0010] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0011] This invention provides a smart energy meter based on a RISC-V-M4 core MCU, comprising:

[0012] The core control module uses a 32-bit RISC-V core M4 microcontroller with a built-in DSP instruction set and FPU unit for metering data processing, communication protocol parsing, load monitoring and low power management.

[0013] The high-precision metering module is connected to the core control module via a UART interface. It includes a metering chip, a voltage sampling circuit, and a current sampling circuit, and is used to acquire raw data of active power, reactive power, apparent power, and harmonics.

[0014] A multi-protocol communication module includes a wired communication unit and a wireless communication unit. The wired communication unit extends the RS485 interface through an AZRS485 interface chip. The wireless communication unit includes at least one of an RF433 module, a Bluetooth module, a 2G / 4G module, and a G3-PLC module.

[0015] The dynamic load monitoring module includes a current transformer, a voltage divider circuit, and a comparator circuit. The current transformer and the voltage divider circuit are used to collect the load current change rate and voltage change rate, respectively. The comparator circuit is used to set overcurrent, overvoltage, and undervoltage thresholds and trigger the interrupt response of the core control module.

[0016] The low-power management unit includes a power module and a power control circuit. The power module is used to provide a stable voltage, and the power control circuit controls the power supply of each functional module through the GPIO port of the microcontroller.

[0017] The storage and display module includes a storage unit and a display unit. The storage unit is used to store metering data and configuration parameters, and the display unit is connected to an LCD screen via an I2C interface.

[0018] Furthermore, the microcontroller is model CM32M4RQ8L7, with built-in 512K Flash and 144KB SRAM, and supports DMA data transfer.

[0019] Furthermore, the metering chip is model HT7017C, with a built-in 19-bit ADC and a sampling rate of 2MHz.

[0020] Furthermore, the multi-protocol communication module also includes a communication switching unit, which is controlled by the microcontroller to switch analog switches automatically according to the network status; the multi-protocol communication module supports remote program upgrade function.

[0021] Furthermore, the dynamic load monitoring module also includes a load analysis unit, which calculates the load imbalance and peak impact load using a DSP instruction set to determine the load operating status.

[0022] Furthermore, the power module of the low-power management unit adopts the SGM2203 low-power LDO, which outputs a stable voltage of 3.3V and a quiescent current of 1.5μA.

[0023] Furthermore, the multi-mode power management of the low-power management unit includes:

[0024] Normal operating mode: All modules are started, and the microcontroller's main frequency is 168MHz;

[0025] Sleep mode: During non-metering periods, the microcontroller's main frequency drops to 8MHz, the power supply to the high-precision metering module and the multi-protocol communication module is turned off, and only the timed wake-up function is retained;

[0026] Deep sleep mode: When there is no load for a long time, the microcontroller enters Stop2 mode, the power consumption drops to 5μA, and it is woken up by an external interrupt.

[0027] Furthermore, the storage unit employs an ESMT Flash memory and an M24512 EEPROM memory. The ESMT Flash memory is used to store historical measurement data and parameter configurations, and the M24512 EEPROM memory is used to store calibration data and fault records. The display unit is used to display real-time electrical parameters, communication status, and fault information.

[0028] Furthermore, the microcontroller adopts the FreeRTOS real-time operating system and implements multi-task scheduling based on the M4 kernel NVIC, including metering tasks, communication tasks, load monitoring tasks, and display tasks. The microcontroller implements the FFT algorithm based on the DSP instruction set, performs 2nd to 31st harmonic analysis on the raw data collected by the metering chip, and uses a moving average filtering algorithm to filter the metering data. It also introduces a temperature compensation algorithm, which collects the ambient temperature through a built-in temperature sensor to correct metering errors.

[0029] Furthermore, the microcontroller implements the Modbus-RTU protocol stack and MQTT protocol stack, supports AES-128 encrypted data transmission, and has a communication status monitoring mechanism. When a certain communication method is abnormal, the microcontroller automatically switches to the backup communication channel and uploads fault alarm information. The dynamic load monitoring module also has an audible and visual alarm unit. When the load current change rate, voltage change rate, or three-phase imbalance exceeds a set threshold, the microcontroller controls the buzzer and LED through the GPIO port to perform local audible and visual alarms and remotely uploads fault information, including the fault occurrence time and fault type, which is stored in the M24512 EEPROM memory.

[0030] Compared with existing technologies, the smart energy meter based on a RISC-V-M4 core MCU provided by this invention has at least the following advantages:

[0031] Traditional electricity meters suffer from insufficient computing power, limited communication protocols, lack of load monitoring, inadequate power consumption control, and limited metering accuracy. This invention effectively improves metering accuracy by leveraging a RISC-V core DSP instruction set and FPU unit to optimize the FFT harmonic analysis algorithm, achieving a metering accuracy of 0.1 level and a harmonic measurement error of ≤±1%, meeting the high-precision metering requirements of smart grids. This invention boasts strong communication compatibility, supporting multiple communication protocols including RS485, RF433, Bluetooth, 2G / 4G, and G3-PLC, adapting to various scenarios such as industrial, residential, and remote areas, with a data transmission success rate ≥99.5%. This invention achieves intelligent load monitoring, enabling real-time monitoring of load status, fault warning, and dynamic adjustment, reducing grid operation and maintenance costs. This invention features low power consumption; through multi-mode power management, standby power consumption is reduced to 5μA, a 60% reduction compared to traditional electricity meters, extending battery life. The M4 core MCU supports peripheral expansion (such as infrared communication), allowing for the addition of functions like electricity pricing and remote control as needed. Attached Figure Description

[0032] To more clearly illustrate the solution of the present invention, a brief introduction will be given to the drawings used in the description of the embodiments below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0033] Figure 1 This invention provides a framework diagram of a smart energy meter based on a RISC-V-M4 core MCU.

[0034] Figure 2This invention provides a circuit diagram of a power module in a smart energy meter based on a RISC-V-M4 core MCU.

[0035] Figure 3 This invention provides a software architecture diagram for a smart energy meter based on a RISC-V-M4 core MCU. Detailed Implementation

[0036] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0038] This invention provides a smart energy meter based on a RISC-V-M4 core MCU, applicable to smart grid construction. The smart energy meter based on a RISC-V-M4 core MCU includes:

[0039] The core control module employs a 32-bit RISC-V core M4 microcontroller with a built-in DSP instruction set and FPU unit, used for metering data processing, communication protocol parsing, load monitoring, and low-power management. The high-precision metering module, connected to the core control module via a UART interface, includes a metering chip, voltage sampling circuit, and current sampling circuit, used for raw acquisition of active power, reactive power, apparent power, and harmonic data. The multi-protocol communication module includes wired and wireless communication units. The wired communication unit extends the RS485 interface via an AZRS485 interface chip, while the wireless communication unit includes an RF433 module, a Bluetooth module, a 2G / 4G module, and a G3-P module. At least one of the LC modules; a dynamic load monitoring module, including a current transformer, a voltage divider circuit, and a comparator circuit, wherein the current transformer and the voltage divider circuit are used to collect the load current change rate and voltage change rate, respectively, and the comparator circuit is used to set overcurrent, overvoltage, and undervoltage thresholds and trigger the interrupt response of the core control module; a low-power management unit, including a power supply module and a power control circuit, wherein the power supply module is used to provide a stable voltage, and the power control circuit controls the power supply on and off of each functional module through the GPIO port of the microcontroller; a storage and display module, including a storage unit and a display unit, wherein the storage unit is used to store metering data and configuration parameters, and the display unit is connected to an LCD display screen through an I2C interface.

[0040] This invention solves the problems of insufficient computing power, single communication protocol, lack of load monitoring, insufficient power consumption control and limited metering accuracy of traditional electricity meters, improves the intelligence level and operational stability of electricity meters, and is suitable for electricity metering in multiple scenarios such as industrial power distribution and residential electricity consumption.

[0041] To enable those skilled in the art to better understand the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0042] This invention provides a smart energy meter based on a RISC-V-M4 core MCU, applicable to smart grid construction, combined with... Figures 1 to 3 In this embodiment, the smart energy meter based on the RISC-V-M4 core MCU includes:

[0043] The core control module uses a 32-bit RISC-V core M4 microcontroller, model CM32M4RQ8L7, as the system control core. The microcontroller has a built-in DSP instruction set and FPU unit for metering data processing, communication protocol parsing, load monitoring, and low power management.

[0044] The high-precision metering module connects to the core control module via a UART interface. It includes a metering chip, a voltage sampling circuit, and a current sampling circuit. It is used to acquire raw data of active power, reactive power, apparent power, and harmonics. The metering chip is model HT7017C, which acquires single-phase voltage (230V) and current (0-100A) signals. The metering chip has a built-in 19-bit ADC with a sampling rate of up to 2MHz to ensure data acquisition accuracy.

[0045] The multi-protocol communication module includes a wired communication unit, a wireless communication unit, and a communication switching unit. The wired communication unit extends the RS485 interface through the AZRS485 interface chip, supports the Modbus-RTU protocol, and is suitable for wired transmission in industrial power distribution scenarios. The wireless communication unit includes at least one of the following: an RF433 module (communication distance 1-3km), a Bluetooth module, a 2G / 4G module, and a G3-PLC module, enabling remote data uploading and command reception, as well as remote program upgrade functionality. The communication switching unit is controlled by a microcontroller to control an analog switch, automatically switching the communication mode according to the network status to ensure data transmission stability.

[0046] The dynamic load monitoring module includes a current transformer (CT), a voltage divider circuit, a comparator circuit, and a load analysis unit. The current transformer and voltage divider circuit are used to collect the load current change rate and voltage change rate, respectively. The comparator circuit is used to set overcurrent, overvoltage, and undervoltage thresholds and trigger the interrupt response of the core control module. In the load analysis unit, the microcontroller calculates the load imbalance and peak impact load through the DSP instruction set to determine the load operating status.

[0047] The low-power management unit includes a power supply module and a power control circuit. The power supply module uses an SGM2203 low-power LDO, outputting a stable 3.3V voltage with a quiescent current of only 1.5μA, and is used to provide a stable voltage. The power control circuit controls the power supply of each functional module through the microcontroller's GPIO ports. During non-operating periods, the metering chip and communication module are powered off, leaving only the core control module running at low power. The low-power management unit also includes a wake-up mechanism, supporting timed wake-up (configurable period) and external interrupt wake-up (triggered by load surge).

[0048] In this embodiment, the low-power management strategy of the low-power management unit includes:

[0049] Normal operating mode: All modules are started, and the microcontroller's main frequency is 168MHz;

[0050] Sleep mode: During non-metering periods (such as nighttime off-peak load), the microcontroller's main frequency drops to 8MHz, the metering chip and communication module are powered off, and only the timed wake-up function is retained;

[0051] Deep sleep mode: When there is no load for a long time, the microcontroller enters Stop2 mode, the power consumption drops to 5μA, and it is woken up by an external interrupt (load access).

[0052] The storage and display module includes a storage unit and a display unit. The storage unit uses an ESMT Flash memory and an M24512 EEPROM memory. The ESMT Flash memory is used to store measurement data and configuration parameters, and the M24512 EEPROM memory is used to store calibration data and fault records. The display unit is connected to an LCD screen via an I2C interface to display real-time electrical parameters, communication status, and fault information.

[0053] Furthermore, in this embodiment, the software system of the smart energy meter based on the RISC-V-M4 core MCU includes a bootloader, a basic software platform, and a software platform function extension. After each reset, the smart energy meter first runs the bootloader program to check if a program upgrade is needed. If the program does not need an upgrade or the upgrade is completed, the smart energy meter jumps to the basic software platform. The basic software platform only contains the most basic metering and clock functions of the meter. By registering the functional module tasks of the software platform function extension to the task queue of the basic software platform, the energy function is extended, realizing flexible configuration and arbitrary tailoring of the energy meter functions. The overall structure of the software platform includes a driver layer, a system layer, and an application layer. The driver layer completes the development of MCU drivers, device drivers, and device abstraction layer drivers. The driver layer provides standard access interfaces to the outside world, and the upper-layer software accesses hardware resources through the standard driver interfaces, realizing the platform-independent design of the upper-layer software. The system layer software includes front-end and back-end system solutions and operating system solutions. The software platform initially considered to implement the front-end and back-end system solutions, including task scheduling, storage space management, and data interaction mechanism definition. Above the system layer are the corresponding application layer functional modules, among which the basic functions of legal metering belong to the basic part of the software platform. Other application layer functional modules belong to the extensible functional parts, and the configurable design of the electricity meter functions is realized through the software configuration scheme.

[0054] Data management considers a data encapsulation design scheme, where each functional module's private data is encapsulated within that module, allowing each module to handle data updates, backups, and fault tolerance independently. Each functional module provides a standard data object access interface, through which other modules access each other's data.

[0055] Furthermore, in this embodiment, the microcontroller uses the FreeRTOS real-time operating system and implements multi-task scheduling based on the M4 kernel-based NVIC (Nested Vector Interrupt Controller), including metering tasks, communication tasks, load monitoring tasks, and display tasks. The microcontroller implements the FFT (Fast Fourier Transform) algorithm based on the DSP instruction set to perform 2nd to 31st harmonic analysis on the raw data collected by the metering chip, and uses a moving average filtering algorithm to filter the metering data, eliminating grid interference noise and improving the stability of the metering data. A temperature compensation algorithm is also introduced, using a built-in temperature sensor to collect ambient temperature to correct metering errors.

[0056] Furthermore, in this embodiment, the microcontroller implements the Modbus-RTU protocol stack and the MQTT protocol stack, supports AES-128 encrypted data transmission, and has a communication status monitoring mechanism. When a certain communication method is abnormal, the microcontroller automatically switches to the backup communication channel and uploads fault alarm information. The dynamic load monitoring module also has an audible and visual alarm unit, which calculates the load current / voltage change rate and three-phase imbalance in real time. When the load current change rate, voltage change rate, or three-phase imbalance exceeds the set threshold, the microcontroller controls the buzzer and LED through the GPIO port to perform local audible and visual alarms and remotely uploads fault information, including the fault occurrence time and fault type, which is stored in the M24512 EEPROM memory for later traceability.

[0057] Compared with existing technologies, the smart energy meter based on the RISC-V-M4 core MCU described in the above embodiments has the advantages of the traditional energy meter, which suffers from insufficient computing power, single communication protocol, lack of load monitoring, insufficient power consumption control and limited metering accuracy. This invention effectively improves metering accuracy. Leveraging the RISC-V core DSP instruction set and FPU unit, it optimizes the FFT harmonic analysis algorithm, achieving a metering accuracy of 0.1 level with harmonic measurement error ≤ ±1%, meeting the high-precision metering requirements of smart grids. This invention boasts strong communication compatibility, supporting multiple communication protocols including RS485, RF433, Bluetooth, 2G / 4G, and G3-PLC, adapting to various scenarios such as industrial, residential, and remote areas, with a data transmission success rate ≥ 99.5%. This invention achieves intelligent load monitoring, enabling real-time monitoring of load status, fault warning, and dynamic adjustment, reducing grid operation and maintenance costs. This invention has low power consumption; through multi-mode power management, standby power consumption is reduced to 5μA, a 60% reduction compared to traditional electricity meters, extending battery life. The M4 core MCU supports peripheral expansion (such as infrared communication), allowing for the addition of functions like electricity pricing and remote control as needed.

[0058] Obviously, the embodiments described above are merely preferred embodiments of the present invention, and not all embodiments. The accompanying drawings illustrate preferred embodiments of the present invention, but do not limit the scope of the patent. The present invention can be implemented in many different forms; rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing specific embodiments, or make equivalent substitutions for some of the technical features. Any equivalent structures made using the content of this specification and drawings, directly or indirectly applied to other related technical fields, are similarly within the scope of patent protection of this invention.

Claims

1. A smart energy meter based on a RISC-V-M4 core MCU, characterized in that, include: The core control module uses a 32-bit RISC-V core M4 microcontroller with a built-in DSP instruction set and FPU unit for metering data processing, communication protocol parsing, load monitoring and low power management. The high-precision metering module is connected to the core control module via a UART interface. It includes a metering chip, a voltage sampling circuit, and a current sampling circuit, and is used to acquire raw data of active power, reactive power, apparent power, and harmonics. A multi-protocol communication module includes a wired communication unit and a wireless communication unit. The wired communication unit extends the RS485 interface through an AZRS485 interface chip. The wireless communication unit includes at least one of an RF433 module, a Bluetooth module, a 2G / 4G module, and a G3-PLC module. The dynamic load monitoring module includes a current transformer, a voltage divider circuit, and a comparator circuit. The current transformer and the voltage divider circuit are used to collect the load current change rate and voltage change rate, respectively. The comparator circuit is used to set overcurrent, overvoltage, and undervoltage thresholds and trigger the interrupt response of the core control module. The low-power management unit includes a power module and a power control circuit. The power module is used to provide a stable voltage, and the power control circuit controls the power supply of each functional module through the GPIO port of the microcontroller. The storage and display module includes a storage unit and a display unit. The storage unit is used to store metering data and configuration parameters, and the display unit is connected to an LCD screen via an I2C interface.

2. The smart energy meter based on a RISC-V-M4 core MCU according to claim 1, characterized in that, The microcontroller has a built-in 512K Flash and 144KB SRAM and supports DMA data transfer.

3. The smart energy meter based on a RISC-V-M4 core MCU according to claim 1, characterized in that, The metering chip has a built-in 19-bit ADC with a sampling rate of 2MHz.

4. The smart energy meter based on a RISC-V-M4 core MCU according to claim 1, characterized in that, The multi-protocol communication module also includes a communication switching unit, which is controlled by the microcontroller to switch analog switches and automatically switch communication modes according to network status; the multi-protocol communication module supports remote program upgrade function.

5. A smart energy meter based on a RISC-V-M4 core MCU according to claim 1, characterized in that, The dynamic load monitoring module also includes a load analysis unit, which calculates the load imbalance and peak impact load using a DSP instruction set to determine the load operating status.

6. A smart energy meter based on a RISC-V-M4 core MCU according to claim 1, characterized in that, The power module of the low-power management unit adopts a low-power LDO, outputs a stable voltage of 3.3V, and has a quiescent current of 1.5μA.

7. A smart energy meter based on a RISC-V-M4 core MCU according to claim 6, characterized in that, The low-power management unit includes multi-mode power management: Normal operating mode: All modules are started, and the microcontroller's main frequency is 168MHz; Sleep mode: During non-metering periods, the microcontroller's main frequency drops to 8MHz, the power supply to the high-precision metering module and the multi-protocol communication module is turned off, and only the timed wake-up function is retained; Deep sleep mode: When there is no load for a long time, the microcontroller enters Stop2 mode, the power consumption drops to 5μA, and it is woken up by an external interrupt.

8. A smart energy meter based on a RISC-V-M4 core MCU according to claim 1, characterized in that, The storage unit uses a Flash memory and an EEPROM memory. The Flash memory is used to store historical measurement data and parameter configurations, and the EEPROM memory is used to store calibration data and fault records. The display unit is used to display real-time electrical parameters, communication status, and fault information.

9. A smart energy meter based on a RISC-V-M4 core MCU according to claim 1, characterized in that, The microcontroller uses the FreeRTOS real-time operating system and implements multi-task scheduling based on the M4 kernel NVIC, including metering tasks, communication tasks, load monitoring tasks, and display tasks. The microcontroller implements the FFT algorithm based on the DSP instruction set, performs 2nd to 31st harmonic analysis on the raw data collected by the metering chip, and uses a moving average filtering algorithm to filter the metering data. It also introduces a temperature compensation algorithm, which collects the ambient temperature through a built-in temperature sensor to correct metering errors.

10. A smart energy meter based on a RISC-V-M4 core MCU according to claim 8, characterized in that, The microcontroller implements the Modbus-RTU protocol stack and MQTT protocol stack, supports AES-128 encrypted data transmission, and has a communication status monitoring mechanism. When a certain communication method is abnormal, the microcontroller automatically switches to the backup communication channel and uploads fault alarm information. The dynamic load monitoring module also has an audible and visual alarm unit. When the load current change rate, voltage change rate, or three-phase imbalance exceeds a set threshold, the microcontroller controls the buzzer and LED through the GPIO port to perform local audible and visual alarms and remotely uploads fault information, including the fault occurrence time and fault type, which is stored in the EEPROM memory.

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