CN201053976Y - Multi-loop electric energy metering device in low voltage distribution field - Google Patents

Abstract

The utility model discloses a multiloop electrical energy gauging device used in a power distribution offtrack circuit with a simple monitoring request. The multiloop electrical energy gauging device comprises plural loop current input ends, plural high speed signal switches, an electrical energy measuring chip and a microprocessor. The utility model is characterized in that each loop current input end is connected with a signal input end of each high speed signal switch; a control pin of each high speed signal switch is connected with the control pin of the microprocessor; a signal output end of each high speed signal switch is connected with a current channel of the electrical energy measuring chip; busbar voltage enters into a voltage channel end of the electrical energy measuring chip; the electrical energy measuring chip is connected together with a SPI communication port of the microprocessor; the microprocessor controls the switching sequence of the plural high speed signal switches at certain time, thereby realizing the monitoring to the multiloop electric quantity such as the busbar voltage, the loop current, the power, etc. The utility model greatly simplifies the design of the system, reduces the equipment cost, and simplifies the user investment. In addition, the utility model has convenient use, examination and repair for the user.

Description

A multi-circuit electric energy metering device in the field of low-voltage power distribution

technical field

The utility model generally relates to an electric energy metering device, in particular to a multi-circuit electric energy metering device in the field of low-voltage power distribution.

Background technique

As shown in Figure 1, a multi-circuit electric energy metering device adopts a multi-way switch, an A/D conversion chip and a control CPU, and the current signals of multi-way loads flow into A/D after passing through multi-way electronic switches. D conversion chip, the signal after A/D conversion flows into the CPU, and the CPU calculates and processes the signal to calculate the electrical parameters of each load. The advantage of this solution is that the cost is low; the disadvantage is that the software implementation is difficult and the development cycle is long, which is not conducive to the rapid production and operation of the product.

As shown in Figure 2, another multi-circuit electric energy metering device uses multiple A/D conversion chips and a control CPU. The current signals of multiple loads flow into the A/D conversion chips respectively, and the A/D converted signals flow into the CPU. , the signal is calculated and processed by the CPU, and the electrical parameters of each load are calculated. The advantage of this solution is high measurement accuracy; the disadvantages are high cost, difficult software implementation, and long development cycle, which is also unfavorable for rapid production and operation of products.

As shown in Figure 3, another multi-circuit electric energy metering device adopts multiple electric energy metering chips and a control CPU. To the CPU, the signal is processed by the CPU. The advantage of this scheme is high measurement accuracy, easy software implementation, and short development cycle; the disadvantage is high cost, which is not conducive to mass production.

Chinese patent application CN 02139693.0 provides an integrated electric meter for intelligent electric energy measurement and control, which adopts a microprocessor CPU and multiple electronic components, and is packaged in a plastic shell with a panel designed on the shell, which is characterized in that the metering of multiple user circuits, The control device is highly integrated, which constitutes a power sampling and counting module, a central microprocessor (CPU) module, a serial data read-write memory module, a serial communication module, a switch control module, a working power module, a display module and a key circuit module; Most of the components of the power sampling and counting module are integrated on the counter board, the central microprocessor (CPU) module, the serial data read-write memory module, and the serial communication module are integrated on the CPU board, and the pull-on control module is integrated on the pull-off board. On the gate circuit board, the working power supply module is integrated on the switching power supply board, and the display module and the button circuit module are integrated on the display board; the working process is: after the integrated electric meter is initialized, the electric energy sampling and counting module collects the user's electricity consumption data, and uses The electrical data is sent to the CPU for calculation and then saved to the serial data read-write memory module, and reported to the power supply bureau and the meter reader through the serial communication module. The user can also check the power consumption situation at any time through the display circuit, and set the switch on and off The control module controls the user's over-power consumption and arrears switching off and prompting payment. This process can be divided into integrated meter initialization, power sampling and counting, power data storage, over-power processing, error processing, external communication, and remote pull. , Closing processing, display and calibration. However, it does not solve the problem of realizing the electric energy metering of multiple circuits through a single modular device.

Utility model content

The utility model aims to provide a high-performance, low-cost, simple and practical multi-circuit electric energy metering device in the field of low-voltage power distribution, which is mainly used in power distribution outlet circuits with relatively simple monitoring requirements.

A multi-loop electric energy metering device in the field of low-voltage power distribution, including a plurality of loop current input terminals, a plurality of high-speed signal switching switches, an electric energy measurement chip and a microprocessor, characterized in that: the loop current input terminals are connected to high-speed signal switching switches The signal input terminal of the high-speed signal switching switch is connected to the control pin of the microprocessor, and its signal output terminal is connected to the current channel of the electric energy metering chip, and the bus voltage enters the voltage channel end of the electric energy metering chip, and the electric energy metering chip and the microprocessor The SPI communication port of the device is connected together.

In the utility model, the multi-circuit electric energy metering device in the field of low-voltage power distribution is provided with a programmable limit alarm output interface of a switching value, which can be freely set by the user to monitor some abnormal conditions in the power grid and loads and output an alarm.

The multi-circuit electric energy metering device in the field of low-voltage power distribution also has the function of monitoring the switch states of multiple circuits.

The multi-circuit electric energy metering device in the low-voltage power distribution field has a standard RS485 interface, adopts the MODBUS-RTU protocol, and completes intelligent "telemetry", "remote signaling", "remote control" functions and intelligent power distribution management of fault alarm output in the power distribution circuit Require.

In the utility model, the loop current input terminal includes a current transformer, two sampling resistors and an RC filter circuit, and the signal output terminal of the current transformer is connected to the signal input terminal of the high-speed signal switching switch after being filtered by the sampling resistor and RC.

In the utility model, the bus voltage is connected to the voltage monitoring terminal of the electric energy metering chip through a current-type voltage transformer, a sampling resistor and an RC filter circuit.

The multi-circuit electric energy metering device in the low-voltage power distribution field of the utility model can monitor the bus voltage and the circuit current in multiple distribution circuits, and can also measure the power and electric energy of the distribution circuits to realize electric energy measurement management and distribution circuits. The switch status signal in the control device can also be input into the monitoring device, and the switch signal of the load circuit can be monitored locally and remotely, and the functions of measurement, metering, switch status monitoring, control and digital communication of many distribution circuits can be integrated. In one, it greatly simplifies the design of the system, reduces the cost of equipment, reduces the investment of users, and facilitates the use and maintenance of users. It will definitely lead the development direction of the field of intelligent power distribution at home and abroad, and become the outlet circuit The mainstream of monitoring system development.

Description of drawings

Fig. 1 is a schematic diagram of a multi-circuit electric energy metering device in the prior art.

Fig. 2 is a schematic diagram of another multi-circuit electric energy metering device in the prior art.

Fig. 3 is a schematic diagram of another multi-circuit electric energy metering device in the prior art.

Fig. 4 is a schematic diagram of the multi-circuit electric energy metering device of the present invention.

Fig. 5 is a wiring diagram of Embodiment 1 of the present utility model.

FIG. 6 is a schematic circuit diagram of Embodiment 1 of the present utility model.

Figure 7 is a schematic diagram of the high-speed signal changeover switch CD4052.

Figure 8 is a schematic diagram of switch input.

Figure 9 is a schematic diagram of the output of the switching value exceeding the limit.

Fig. 10 is a diagram of the sampling process of Embodiment 1 of the present utility model.

Fig. 11 is a wiring diagram of Embodiment 2 of the present utility model.

Fig. 12 is a schematic circuit diagram of Embodiment 2 of the present utility model.

Fig. 13 is a diagram of the sampling process of Embodiment 2 of the present invention.

Detailed ways

In order to make the technical means, creative features, goals and effects achieved by the utility model easy to understand, the utility model will be further elaborated below in conjunction with specific illustrations.

Example 1

As shown in Figure 4, the utility model adopts a plurality of electronic switching switches, an electric energy metering chip and a control CPU in order to realize the multi-circuit electric energy measurement, the current signal of the multi-path load flows into the electronic switch, and the electronic switch is under the control of the CPU. The conduction is controlled in sequence, the signal flows into the power chip, the power chip calculates the electrical parameters of each load, and then transmits it to the CPU, and the CPU processes the signal. Compared with the three implementation schemes in the background technology, the utility model solves the shortcomings of high cost and long software development cycle; and ensures considerable measurement accuracy, and is especially suitable for general applications that do not require high measurement accuracy and real-time performance. Distribution outlet circuit. Below in conjunction with accompanying drawing, set forth the utility model in detail.

As shown in Figure 6, a multi-circuit electric energy metering device in the field of low-voltage power distribution, this embodiment is a three-phase multi-circuit electric energy metering device, in which there are 9 loop current input terminals, so it can monitor the three-phase buses UA, UB, UC and 9 currents of 3 three-phase circuits. This monitoring device is also equipped with a standard RS485 interface, which can use the MODBUS-RTU protocol to complete the intelligent "telemetry", "remote signaling", "remote control" functions and faults in the power distribution circuit. Intelligent power distribution management for alarm output; set switch input and switch output interfaces to monitor the switch status of 9 circuits.

Referring to Figure 6, the loop current input terminal includes a current transformer, and the monitored loop current enters the monitoring device through the current transformer, sampling resistor and RC filter network. The current transformer, two sampling resistors and two filter capacitors are conventionally connected.

In this embodiment, as shown in Figure 7, the high-speed signal switching switches IC3, IC4, and IC5 adopt CD4502, and this electronic switch is a dual-four selection one, that is, the input has 4 dual-way signals (pin 12 and 1 are the first road input , 14, 5 pins are the 2nd input, 15, 2 pins are the 3rd input, 11, 4 pins are the 4th input), the output is a dual (13, 3 pins are output), which is controlled by the micro The processor controls the on and off of its channel (pins 10 and 9 are control pins), and the control timing is shown in the table below:

B A CD4052B 0011 0101 0X, 0Y1X, 1Y2X, 2Y3X, 3Y

When both pins A and B are at low level, the signals output by pins 13 and 3 are the signals input by pins 12 and 1; when pin A is high and pin B is low, the signals output by pins 13 and 3 are The signal is the signal input by pin 14 and 5; when pin A is low level and pin B is high level, the signal output by pin 13 and pin 3 is the signal input by pin 15 and pin 2; when pin A and B are both When the level is high, the signals output by pins 13 and 3 are the signals input by pins 11 and 4.

Cooperating with the 9 currents of the 3 loops, 3 high-speed signal switching switches IC3, IC4 and IC5 are set, and the 9 current input terminals are respectively connected with the input terminals of the high-speed signal switching switch. 9 current input terminals (for clear identification, the 9 currents are divided into three groups of A, B and C, each group has 3 circuits), from top to bottom are the A-phase current IA ₁₊ and IA of the first three-phase load _1- Flow into the Y0 and X0 pins of the high-speed signal switch IC3 respectively, and the B-phase current IB ₁₊ and IB ₁ of the first three-phase load flow into the Y0 and X0 pins of the high-speed signal switch IC4 respectively, and the first three-phase load The C-phase current IC ₁₊ and IC _{1- of} the load flow into the Y0 and X0 pins of the high-speed signal switching switch IC5 respectively; the A-phase current IA ₂₊ and IA _2- of the second three-phase load flow into the high-speed signal switching switch IC3 respectively Y1, X1 pins, the B-phase current IB ₂₊ , IB _2- of the second three-phase load flow into the Y1, X1 pins of the high-speed signal switch IC4 respectively, and the C-phase current IC ₂₊ , IC of the second three-phase load _2- Flow into the Y1 and X1 pins of the high-speed signal switch IC5 respectively; the A-phase current IA ₃₊ and IA _3- of the third three-phase load flow into the Y2 and X2 pins of the high-speed signal switch IC3 respectively, and the third three-phase load The load B-phase current IB ₃₊ , IB _3- flows into the Y2 and X2 pins of the high-speed signal switch IC4 respectively, and the C-phase current IC ₃₊ and IC _3- of the third three-phase load flow into the Y2 of the high-speed signal switch IC5 respectively , X2 feet.

The high-speed signal switching switch IC3, IC4, IC5 switch control pin A is connected together and connected with the IO port PTC2 of the microcontroller IC6/MC9S08AW32, and the control pin B is connected together and connected with the IO port PTC4 of the microcontroller IC6/MC9S08AW32 The output ports YOUT and XOUT of the high-speed signal switching switch IC3 are respectively connected to the IAP and IAN ports of the energy metering chip IC1/ADE7758, and the output ports YOUT and XOUT of the high-speed signal switching switch IC4 are respectively connected to the IBP, IBP, and The IBN port is connected, and the output ports YOUT and XOUT of the high-speed signal switching switch IC5 are respectively connected to the ICP and ICN ports of the electric energy metering chip IC1/ADE7758.

The electric energy measurement chip IC1/ADE7758 is a high-precision three-phase electric energy measurement IC, which integrates digital integration, reference voltage source, temperature sensitive components, etc., and can be used for the measurement of active power, complex power, apparent power and effective value And the signal processing circuitry necessary to digitally correct system errors (gain, phase, offset, etc.). The chip is suitable for measuring active power, complex power and apparent power in various three-phase circuits (regardless of three-wire system or four-wire system). Among them, the current channel is input by three pairs of differential voltages, which are IAP pin, IAN pin, IBP pin, IBN pin, ICP pin, and ICN pin. The voltage channel has three single-ended voltage input channels, which are VAP pin, VBP pin, VCP pin, and VN pin. The DOUT pin, the SCLK pin, the DIN pin, and the CS pin are SPI communication pins, which are used to communicate with the microprocessor to transmit data.

The three-phase bus voltages UA, UB, and UC are sampled through voltage transformers, sampling resistors, and RC filter circuits and enter the VAP pin, VBP pin, VCP pin, and VN pin of the electric energy metering chip IC1/ADE7758; the IQR of the electric energy metering chip IC1/ADE7758 Pin, CS pin, DIN pin, SCK pin and DOUT pin are connected to the bus to connect the PTE5/MISO pin, PTE6/MOSI pin and PTE7/SPSCK pin of the microprocessor MC9S08AW32 for data communication.

PTC1/SDA pin and PTC0/SCL pin of microprocessor IC6/MC9S08AW32 are connected with non-volatile ferroelectric RAM IC2/FM24C16A for data storage.

Referring to Figure 8, taking U2 as an example, the input terminal is DI-1, that is, the external switching signal is input through DI-1. When the external switch signal is closed, DI-1 is connected to the ground, and the current signal flows into the optocoupler U2 after passing through the current limiting resistor R4 (R22 is a shunt resistor). The C and E pins inside the optocoupler are also turned on, so that the input DI1 is low level, and DI1 is connected to the digital input interface of the microprocessor IC6/MC9S08AW32, and the microprocessor IC6/MC98S08AW32 reads the low level of DI1 to Judging that the input switch is in the closing state.

If the external switch signal is open, DI-1 is not connected to the ground, and the inside of the optocoupler is not turned on, then DI1 is at high level, and the single-chip microcomputer judges that the input switch value is open by reading the high level of DI1. gate status. PTD0/AD8 pins, PTD1/AD9 pins, PTD2/KBI5 pins, PTD3/KBI6 pins, PTD4/AD12 pins, PTD5/AD13 pins, PTD6/AD14 pins, PTD7/KBI7/AD15 pins on the microprocessor IC6/MC9S08AW32 PTF0/TP12, PTF1/TP13, PTF2/TP14, PTF3/TP15, PTF4/TP20, PTF5/TP21, PTF6, PTF7, PTE3/TP11, PTE2/TP10 are switch input interface.

The PTG4/KBI4 of the microprocessor IC6/MC9S08AW32 is a programmable limit alarm output interface for switching output; its principle is shown in Figure 9. When it is detected that some external set signal exceeds the allowable range, the microprocessor IC6/MC9S08AW32 outputs a high-level signal, and the high-level signal is transmitted to the transistor Q1 through DO1. At this time, the transistor Q1 is turned on, and the internal relay U1 A current flows through the coil to make the contacts close, and DO1+ and DO1- output an alarm signal. When the external limit is not exceeded, DO1 outputs a low-level signal, the relay U1 is disconnected, and there is no alarm signal output.

The PTE1/RXD1 and PTE0/TXD1 pins of the microprocessor IC6/MC9S08AW32 are RS485 communication interfaces, which can communicate with the outside world.

Microprocessor IC6/MC9S08AW32 time-division switching selects the input signals of high-speed signal switching switches IC3, IC4 and IC5, so that the current of different circuits is time-division switched and input to the current input terminal of the electric energy metering chip IC1/ADE7758, so that the electric energy metering chip IC1 The voltage, current, power and electric energy monitored by /ADE7758 are the corresponding bus voltage, the circuit current, power and electric energy selected by the switch, and the microprocessor IC6/MC9S08AW32 can continuously switch the current of different circuits to monitor the multi-power of all different circuits Parameters, the specific process is as follows.

After the system is powered on, initialize the electric energy metering chip IC1/ADE7758, define the electric energy metering chip IC1/ADE7758 as periodic metering, and use the interrupt method. The program defines a variable loop=1, 2, 3 (loop=1 means that the metering is the first three-phase load, loop=2 means that the metering is the second three-phase load, loop=3 means the metering is 3rd three-phase load). The microprocessor IC6/MC9S08AW32 starts to work and controls the electronic switch. When the external interrupt arrives, the microprocessor IC6/MC9S08AW32 reads the current, voltage, power and electric energy value of the last loop from the electric energy metering chip IC1/ADE7758, and Switch the electronic switch to the lower channel.

The whole sampling process is shown in Figure 10. In a complete sampling measurement cycle T, it is divided into three identical time periods t1, t2, and t3, corresponding to loop1, loop2, and loop3 respectively. During the time period of loop1, the microprocessor IC6/MC9S08AW32 controls the electronic switch to turn on the A, B, and C three-phase current I1 of the first three-phase load, so that the electric energy metering chip IC1/ADE7758 can control the first three-phase load. Measure the electrical parameters, and pass the electrical parameters measured by the electric energy metering chip IC1/ADE7758 to the microprocessor IC6/MC98S08AW32, so that the microprocessor IC6/MC98S08AW32 can process the electrical parameters in the loop1 time period, and in the loop2 time period Inside, the microprocessor IC6/MC98S08AW32 controls the electronic switch to conduct the A, B, C three-phase current I2 of the second three-phase load, so that the electric energy metering chip IC1/ADE7758 can measure the electrical parameters of the second three-phase load, And pass the electrical parameters measured by the electric energy metering chip IC1/ADE7758 to the microprocessor IC6/MC9S08AW32, let the microprocessor IC6/MC9S08AW32 process the electrical parameters in the loop2 time period, and in the loop3 time period, the microprocessor IC6/MC9S08AW32 controls the electronic switch to turn on the A, B, C three-phase current I3 of the third three-phase load, so that the electric energy metering chip IC1/ADE7758 can measure the electric parameters of the third three-phase load, and the electric energy metering chip The electrical parameters measured by IC1/ADE7758 are transmitted to the microprocessor IC6/MC9S08AW32, so that the microprocessor IC6/MC9S08AW32 can process the electrical parameters in the loop3 time period. In this way, within the entire sampling period T, each three-phase load is measured for 1/3 of the time. It can be seen from Figure 10 that in the entire sampling period T, for each of the three loads, the effective sampling and measurement time is T/3, and the remaining 2T/3 time period is blank, that is, the current is not adjusted Signal sampling. Therefore, when measuring electric energy, in the entire period T, each of the three loads only measures the electric energy within T/3 time, so to measure the electric energy value of each load within the total period T, we use T/3 time The electric energy value obtained by internal measurement is multiplied by 3 times, that is, the total electric energy of the first three-phase load within T time is ∑P1×t1×3, and the total electric energy of the second three-phase load within T time is ∑P2× t2×3, the total electric energy of the third three-phase load within T time is ΣP3×t3×3, t1=t2=t3. In each period T, the electric energy of each circuit is measured according to the above method, and then the electric energy in each period T is accumulated, and the long-term electric energy value of each load can be obtained.

Example 2

This embodiment is a single-phase multi-loop electric energy metering device, which is equipped with 9 loop current input terminals, so it can monitor the bus voltage UL and 9 loop currents. This monitoring device is also equipped with a standard RS485 interface, which can adopt the MODBUS-RTU protocol , to complete the intelligent "telemetry", "remote signaling", "remote control" functions and intelligent power distribution management of fault alarm output in the power distribution circuit; set the switch input and switch output interfaces, and monitor the switch status of 9 circuits.

Referring to Figure 12, the loop current input terminal includes a current transformer, and the monitored loop current enters the monitoring device through the current transformer, sampling resistor and RC filter network. The current transformer, two sampling resistors and two filter capacitors are conventionally connected.

In this embodiment, as shown in FIG. 7 , the high-speed signal switching switches IC3', IC4', and IC5' adopt CD4502, and its working principle is the same as that described in Embodiment 1, so it will not be repeated here.

Cooperating with the 9 currents of the single-phase circuit, 3 high-speed signal switching switches IC3', IC4' and IC5' are set, and the 9 current input terminals are respectively connected with the input terminals of the high-speed signal switching switch. 9 current input terminals (for clear identification, the 9 currents are divided into three groups A, B, and C, each group has 3 circuits, group A is the 1st, 4th, and 7th single-phase load, and group B is the 2nd, 5th, and 7th single-phase loads. 8 single-phase loads, group C is the 3rd, 6th and 9th single-phase loads), from top to bottom, the current IA ₁₊ and IA _1- of the first single-phase load respectively flow into the high-speed signal switch IC3′ The Y0 and X0 pins of the fourth single-phase load, the current IB ₁₊ and IB _1- of the fourth single-phase load respectively flow into the Y0 and X0 pins of the high-speed signal switching switch IC4′, and the currents of the seventh single-phase load IC ₁₊ and IC _1- respectively flow into the Y0 and X0 pins of the high-speed signal switching switch IC5′; the current IA ₂₊ and IA _2- of the second single-phase load respectively flow into the Y1 and X1 pins of the high-speed signal switching switch IC3′, and the current of the fifth single-phase load The currents IB ₂₊ and IB _2- respectively flow into the Y1 and X1 pins of the high-speed signal switching switch IC4′, and the current IC ₂₊ and IC _2- of the eighth single-phase load respectively flow into the Y1 and X1 pins of the high-speed signal switching switch IC5′ ; The current IA ₃₊ and IA _3- of the third single-phase load flow into the Y2 and X2 pins of the high-speed signal switching switch IC3′ respectively, and the current IB ₃₊ and IB _3- of the sixth single-phase load respectively flow into the high-speed signal switching The Y2 and X2 pins of the switch IC4', the currents IC ₃₊ and IC _3- of the ninth single-phase load respectively flow into the Y2 and X2 pins of the high-speed signal switching switch IC5'.

High-speed signal switching switch IC3', IC4', IC5' switch control pin A is connected together and connected with the IO port PTC2 of the microprocessor IC6'/MC9S08AW32, and the control pin B is connected together and connected with the microprocessor IC6'/MC9S08AW32 The IO port of the high-speed signal switching switch IC3' is connected to the PTC4 port, the output ports YOUT and XOUT of the high-speed signal switching switch IC3' are respectively connected to the IAP and IAN ports of the electric energy metering chip IC1'/ADE7758, and the output ports YOUT and XOUT of the high-speed signal switching switch IC4' are respectively connected to the electric energy metering chip IC1'/ADE7758 The IBP and IBN ports of the metering chip IC1'/ADE7758 are connected, and the output ports YOUT and XOUT of the high-speed signal switching switch IC5' are respectively connected with the ICP and ICN ports of the electric energy metering chip IC1'/ADE7758. In order to improve measurement accuracy, in this example, a three-phase power chip is used to measure the electrical parameters of single-phase loads. In each sampling period, the electrical parameters of three single-phase loads can be measured simultaneously.

The working principle of the electric energy metering chip IC1'/ADE7758 is the same as that described in Embodiment 1, and will not be repeated here. The single-phase bus voltage UL and UN are sampled through the voltage transformer, sampling resistor and RC filter circuit and enter the VAP pin, VN pin, VBP pin, VCP pin and VAP pin of the electric energy metering chip IC1′/ADE7758; the electric energy metering chip IC1′ /ADE7758's IQR pin, CS pin, DIN pin, SCK pin and DOUT pin are connected into a bus to connect the PTE5/MISO pin, PTE6/MOSI pin and PTE7/SPSCK pin of the microprocessor IC6'/MC9S08AW32 for data communication.

PTC1'/SDA pin and PTC0/SCL pin of microprocessor IC6'/MC9S08AW32 are connected with non-volatile ferroelectric RAM IC2'/FM24C16A for data storage.

In this embodiment, the principle of the input and output of the switching value is the same as that of Embodiment 1, and will not be repeated here.

PTC1/SDA pin and PTC0/SCL pin of microprocessor IC6'/MC9S08AW32 are connected with non-volatile ferroelectric RAM IC2'/FM24C16A for data storage.

When working, the microprocessor IC6'/MC9S08AW32 controls the input signals of the high-speed signal switching switches IC3', IC4', and IC5' at the same time, so that the current of different circuits is time-divided and switched to the current channel of the electric energy metering chip IC1'/ADE7758, so that The voltage, current, power and electric energy monitored by the electric energy metering chip IC1′/ADE7758 are the corresponding bus voltage, the circuit current, power and electric energy selected by the switch, and the microprocessor IC6′/MC9S08AW32 continuously switches the current of different circuits to monitor all The multi-power parameters of different circuits, the specific process is as follows.

After the system is powered on, initialize the electric energy metering chip IC1'/ADE7758, define the electric energy metering chip IC1'/ADE7758 as periodic metering, and use the interrupt method. The program defines a variable loop=1, 2, 3 (loop=1 means that the metering is the 1st, 2nd, and 3rd single-phase load, loop=2 means that the metering is the 4th, 5th, and 6th single-phase load, loop= 3 means that the metering is the 7th, 8th, and 9th single-phase load). The microprocessor IC6'/MC9S08AW32 starts to work and controls the electronic switch. When the external interrupt arrives, the microprocessor IC6'/MC9S08AW32 reads the current, voltage, power and electric energy of the last loop from the electric energy metering chip IC1'/ADE7758 value, and switch the electronic switch to the next channel.

The whole sampling process is shown in Figure 13. In a complete sampling measurement cycle T, it is divided into three identical time periods t1, t2, and t3, corresponding to loop1, loop2, and loop3 respectively. During the period of loop1, the CPU controls the electronic switch to turn on the currents I1, I2, and I3 of the first, second, and third single-phase loads, so that the electric energy metering chip IC1′/ADE7758 controls the first, second, and third single-phase loads Carry out the measurement of electrical parameters, and transmit the electrical parameters measured by the electric energy metering chip IC1'/ADE7758 to the microprocessor IC6'/MC9S08AW32, and let the microprocessor IC6'/MC9S08AW32 process the electrical parameters in the loop1 time period, During the period of loop2, the microprocessor IC6'/MC9S08AW32 controls the electronic switch to turn on the currents I4, I5, and I6 of the 4th, 5th, and 6th single-phase loads, so that the electric energy metering chip IC1'/ADE7758 can control the currents of the 4th, 5th, and 6th single-phase loads. The 6-way single-phase load measures the electrical parameters, and transmits the electrical parameters measured by the energy metering chip IC1′/ADE7758 to the microprocessor IC6′/MC9S08AW32, so that the microprocessor IC6′/MC9S08AW32 can measure the electrical parameters in the loop2 time period The parameters are processed. During the time period of loop3, the microprocessor IC6'/MC9S08AW32 controls the electronic switch to turn on the 7th, 8th, and 9th single-phase load currents I7, I8, and I9, so that the electric energy metering chip IC1'/ADE7758 7, 8, and 9 single-phase loads measure the electrical parameters, and transmit the electrical parameters measured by the electric energy metering chip IC1′/ADE7758 to the microprocessor IC6′/MC9S08AW32, so that the microprocessor IC6′/MC9S08AW32 can compare the loop3 time The electrical parameters in the segment are processed. In this way, in the entire sampling period T, each load is measured for 1/3 of the time. It can be seen from Figure 13 that in the entire sampling period T, for each of the 9 loads, the effective sampling and measurement time is T/3, and the remaining 2T/3 time period is blank, that is, the current is not adjusted Signal sampling. Therefore, when measuring electric energy, in the whole period T, each of the 9 loads only measures the electric energy within T/3 time, so to measure the electric energy value of each load within the total period T, we use T/3 time The electric energy value obtained by internal measurement is multiplied by 3 times, that is, the total electric energy of the first load within T time is ΣP1×t1×3, and the total electric energy of the second load within T time is ΣP2×t1×3, The total electric energy of the third load within T time is ∑P3×t1×3, the total electric energy of the fourth load within T time is ∑P4×t2×3, and the total electric energy of the fifth load within T time is ∑P5×t2×3, the total electric energy of the 6th load within T time is ∑P6×t2×3, the total electric energy of the 7th load within T time is ∑P7×t3×3, the 8th load is at T The total electric energy within the time is ΣP8×t3×3, and the total electric energy of the ninth load within the time T is ΣP9×t3×3. In each cycle T, the electric energy of each circuit is measured according to the above method, and then the electric energy in each cycle T is accumulated, and the long-term electric energy value of each load can be obtained.

The basic principles and main features of the present utility model and the advantages of the present utility model have been shown and described above. Those skilled in the art should understand that the utility model is not limited by the above-mentioned embodiments. The above-mentioned embodiments and descriptions only illustrate the principle of the utility model. Without departing from the spirit and scope of the utility model, the utility model The new model also has various changes and improvements, and these changes and improvements all fall within the scope of the claimed utility model. The scope of protection required by the utility model is defined by the appended claims and their equivalents.

Claims (9)

1. A multi-loop electric energy metering device in the field of low-voltage power distribution, comprising a plurality of loop current input terminals, a plurality of high-speed signal switching switches, an electric energy metering chip and a microprocessor, characterized in that: the loop current input terminals are connected to high-speed signal The signal input end of the switch, the control pin of the high-speed signal switch is connected to the control pin of the microprocessor, the signal output end is connected to the current channel of the electric energy metering chip, the bus voltage enters the voltage channel end of the electric energy metering chip, the electric energy metering chip and The SPI communication ports of the microprocessors are connected together. 2. The multi-circuit electric energy metering device according to claim 1, characterized in that it comprises a three-phase multi-circuit electric energy metering device and a single-phase multi-circuit electric energy metering device. 3. The multi-circuit electric energy metering device according to claim 1 or 2, characterized in that the electric energy metering device is provided with a switch state input interface for monitoring the switch state. 4. The multi-circuit electric energy metering device according to claim 1 or 2, characterized in that, the electric energy metering device is provided with an output interface for a programmable switching value exceeding a limit. 5. The multi-circuit electric energy metering device according to claim 1 or 2, characterized in that the electric energy metering device has a standard RS485 interface, and uses the MODBUS-RTU protocol for external data communication. 6. The multi-circuit electric energy metering device according to claim 1 or 2, characterized in that the electric energy metering device is provided with a non-volatile ferroelectric random access memory to ensure safe storage. 7. The multi-loop electric energy metering device according to claim 1 or 2, wherein the loop current input terminal comprises a current transformer, two sampling resistors and an RC filter circuit, and the signal output terminal of the current transformer passes through The sampling resistor and RC filter are then connected to the signal input end of the high-speed signal switching switch. 8. The multi-circuit electric energy metering device according to claim 1 or 2, wherein the bus voltage is connected to the voltage monitoring terminal of the electric energy metering chip through a current-type voltage transformer, a sampling resistor and an RC filter circuit. 9. The multi-circuit electric energy metering device according to claim 1 or 2, characterized in that: the output end of the high-speed signal switching switch is connected as a bus to connect the current channel of the electric energy metering chip.

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