MCP3909-I/SS Microchip Technology, MCP3909-I/SS Datasheet
MCP3909-I/SS
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MCP3909-I/SS Summary of contents
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... MCP3909 / dsPIC33FJ128GP206 © 2009 Microchip Technology Inc. 3-Phase Energy Meter Reference Design DS51823A ...
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... REAL ICE, rfLAB, Select Mode, Total Endurance, TSHARC, UniWinDriver, WiperLock and ZENA are trademarks of Microchip Technology Incorporated in the U.S.A. and other countries. SQTP is a service mark of Microchip Technology Incorporated in the U.S.A. All other trademarks mentioned herein are property of their respective companies. ...
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... Chapter 3. Firmware 3.1 Overview ...................................................................................................... 27 3.2 Main Loop ..................................................................................................... 27 3.3 Calculation() - Calculating Electrical Parameters ......................................... 29 3.4 ADC Sampling Scheme For Calculations .................................................... 33 3.5 ReadING A/D Data Of The MCP3909 Device .............................................. 35 3.6 Communication Of UART Interface .............................................................. 37 3.7 Resource Configuration ................................................................................ 37 3.8 Description Of Project Files .......................................................................... 38 Chapter 4. Meter Calibration 4.1 Introduction ................................................................................................... 39 4 ...
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... MCP3909 / dsPIC33F 3-Phase Energy Meter Reference Design Chapter 5. PC Software 5.1 Overview And Installation ............................................................................. 43 5.2 Establish Communication ............................................................................. 44 5.3 Basic Parameters Output Screen ................................................................. 45 5.4 Phase A/B/C Harmonic Output Screen ........................................................ 45 5.5 Distortion Rate .............................................................................................. 46 5.6 Harmonic Power ........................................................................................... 46 5.7 Energy Accumulation ................................................................................... 47 5.8 Calibration Step 1 - Reset All Calibration ..................................................... 47 5 ...
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... C.13 Compensation For Ratio Error And Phase Lag ......................................... 95 C.14 Relationship Between Error And Current ................................................... 96 C.15 Ratio Error Compensation ......................................................................... 97 C.16 Phase Lag Compensation ......................................................................... 98 Appendix D. 50/60 Hz Meter Operation D.1 Firmware Versions ..................................................................................... 103 Worldwide Sales and Service .................................................................................. 104 © 2009 Microchip Technology Inc. DS51723A-page 5 ...
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... MCP3909 / dsPIC33F 3-Phase Energy Meter Reference Design NOTES: DS51723A-page 6 © 2009 Microchip Technology Inc. ...
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... Select the Help menu, and then Topics to open a list of available on-line help files. INTRODUCTION This chapter contains general information that will be useful to know before using the MCP3909 / dsPIC33F 3-Phase Energy Meter Reference Design. Items discussed in this chapter include: • Document Layout • ...
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... Reference Design as a development tool to emulate and debug firmware on a target board. The manual layout is as follows: This document describes how to use the MCP3909 / dsPIC33F 3-Phase Energy Meter Reference Design as a development tool. The manual layout is as follows: • Chapter 1. “Meter Overview” - Summarizes the meter specifications and a quick getting started section • ...
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... N‘Rnnnn Text in angle brackets < > Courier New font: Plain Courier New Italic Courier New Square brackets [ ] Curly brackets and pipe character Ellipses... © 2009 Microchip Technology Inc. Represents Referenced books MPLAB Emphasized text ...is the only compiler... A window the Output window A dialog ...
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... MCP3909 / dsPIC33F 3-Phase Energy Meter Reference Design RECOMMENDED READING This user's guide describes how to use MCP3909 / dsPIC33F 3-Phase Energy Meter Reference Design. Other useful documents are listed below. The following Microchip documents are available and recommended as supplemental reference resources. MCP3909 Data Sheet, “Energy Metering IC with SPI Interface and Active Power Pulse Output“ ...
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... It uses Microchip’s powerful 16-bit dsPIC33F Microcontroller Unit (MCU). The MCP3909 / dsPIC33F 3-Phase Energy Meter Reference Design is unique in the fact that all calculations take advantage of the dsPIC33F DSP engine, and all output quantities are calculated in the frequency domain through the use of direct fourier transforms (DFT) ...
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... MCP3909 / dsPIC33F 3-Phase Energy Meter Reference Design 1.3 POWER CALCULATIONS A summary of all the calculations performed by this energy meter are summarized below. Chapter 3. “Firmware” provides an explanation on the firmware implementation, Appendix C. “Power Calculation Theory” is included to show the theory behind this firmware. ...
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... MCP3909 / dsPIC33F 3-Phase Energy Meter Reference Design. 1.4 GETTING STARTED To describe how to use the MCP3909 / dsPIC33F 3-Phase Energy Meter Reference Design, the following example is given using a 4-wire, 3-phase, 220VAC line voltage and connection. The rated current of the energy meter is 5(20)A. The energy meters are not shipped fully calibrated, and a full calibration should be performed to show the true meter accuracy. See Chapter 4. “ ...
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... MCP3909 / dsPIC33F 3-Phase Energy Meter Reference Design Step 1: Connect the meter to 220V line and load The diagram below shows where the voltage and current connections should be made not required to connect all 3 phases for the meter to be operational. 220VAC should be placed between either V The AC load for a given phase should then be connected to the I phase ...
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... Windows™ Operating System, and selecting the proper comm port for RS-232 communication, the following screen should show real-time meter results. The following chapters include more detail on the firmware, calculation, and PC software. . FIGURE 1-3: “PM_Viewer” or Power Meter Viewer PC Software. © 2009 Microchip Technology Inc. Meter Overview DS51723A-page 15 ...
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... MCP3909 / dsPIC33F 3-Phase Energy Meter Reference Design NOTES: DS51723A-page 16 © 2009 Microchip Technology Inc. ...
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... Chapter 2. Hardware Description 2.1 OVERVIEW Figure 2-1 is the basic hardware block diagram of the MCP3909 / dsPIC33F 3-Phase Energy Meter Reference Design. The hardware includes the dsPIC33F and ICD 2 interface, analog signal conditioning for 3-phase voltage/current inputs and current using the MCP3909 Energy Meter IC, neutral current measurement using external op-amp on-board dsPIC33F ADC, UART interface to PC, ICD2 interface for MCU programming, and power supply circuits ...
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... CT to transform the signal to an appropriate current. After the CT, burden resistors R 125 age signal for the MCP3909 device to sample. Signals are coupled into the MCP3909 device's signal input port via R quency signals. Using phase example for the current signal path, transformation of the current signal is similar to that of the voltage signal ...
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... Metal film resistors with low inherent noise and temperature coefficient are ideal. Given that the secondary current of the then the input voltage of the MCP3909 device IR, where R is the resistance the temperature varies by ΔT, and the temperature coefficient of sampling resistor R is β ...
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... The programmable range for the MCP3909's PGA is 16:1 V/V. The MCP3909 PGA gain can be configured by G0 and G1 (Pin 15 and 16 of the dsPIC33F). The MCP3909 device's clock is provided by a 3.3768 MHz active crystal (for 50 Hz system, see Appendix D. “50/60 Hz Meter Operation” for 60 Hz line frequency information) ...
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... Data Ready signal is generated by the SDO of the MCP3909 device. The signal is fed into IC data. When the MCP3909 device outputs data, it first sends an ADC result of the voltage channel, then an ADC result of the current channel, with MSB first. As noted, not all MCP3909 device samples are used for calculating all the parameters. ...
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... PULSE1 is total phase active power pulse output, PULSE2 is total phase reactive power pulse output. PULSE3's function determined. Master clear signal of 3 MCP3909 devices (tied together) LED drive pins, can be used as energy pulse output indicator, for meter calibration. Its function is similar to those of ...
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... The output pins for these LEDs are RC13 and RC14. The LED is on when the output is low. Figure 2-4 is the circuit of energy pulse output interface. RD3 RD2 RD1 FIGURE 2-4: © 2009 Microchip Technology Inc. Hardware Description 1 kΩ R 301 1 kΩ ...
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... MCP3909 / dsPIC33F 3-Phase Energy Meter Reference Design 2.4.3 Neutral Current Detection Detection of neutral wire tampering is performed by the on-chip A/D of the dsPIC device. The purpose of the detection is to prevent electricity theft, balance 3-phase signals and detect electricity leakage. Since the precision is not critical, a dsPIC on-chip A/D is sufficient ...
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... JP5 JP6 COILS Vo2 Vo1 FIGURE 2-6: Switching Power Supply Module (T4) and Additional Input Protection Circuitry. © 2009 Microchip Technology Inc. Hardware Description , RV1, RV2 and RV3 are C capacitors and varistors. They are used RV1 C1 0.1U 12V 100uf the integrated ferrite ...
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... MCP3909 / dsPIC33F 3-Phase Energy Meter Reference Design An LDO is connected in series at the output of the switching power supply to obtain a more stable power supply. Figure 2-7 shows this circuit. Microchip's MCP1701 device and MCP1700 device, low drop-out high efficiency LDOs, are selected for use. ...
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... See Appendix D. “50/60 Hz Meter Operation” for converting code. • Calculate all electrical parameters in frequency domain • MCP3909 device communication • Detect voltage/current phase order, and determine missing phases • Generation imp/kWh power pulse • UART communication 3 ...
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... MCP3909 / dsPIC33F 3-Phase Energy Meter Reference Design After system power-up, the MCU enters the initialization process, which includes proper configuration of the I/O ports and on-chip peripherals (such as timer, UART, SPI and IC). At the same time, the system control parameters can be loaded from the external EEPROM and variables are all initialized ...
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... Voltage and Current Distortion Of Each Phase • Voltage and Current Harmonic Contents Of Each Phase Note: Algorithms for all calculations are shown in Appendix C. “Power Calculation Theory”. FIGURE 3-2: © 2009 Microchip Technology Inc. Calculate function Calculate current Select sync. window RMS value function and ...
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... MCP3909 / dsPIC33F 3-Phase Energy Meter Reference Design Each block can be categorized into one of three types of calculations: 1. Calculation for an individual phase 2. Calculation for all 3 phases 3. Calculation of power accumulation (Energy) 3.3.1 Process Quasi-Synchronization Window The first blocks of the calculation flow are to determine how many samples to use for the quasi-synchronization sampling algorithm. See Appendix C. “ ...
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... Additional compensation to the power calculation is required, for phase compensation. This compensation is based on the present load current. The difference between signal frequency and the central frequency is also taken into consideration. Consequently computed power is compensated. © 2009 Microchip Technology Inc. ST harmonic). Firmware DS51723A-page 31 ...
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... MCP3909 / dsPIC33F 3-Phase Energy Meter Reference Design 3.3.6 Active Energy Accumulation Energy accumulation is done by calculating the total energy, which is the algebraic sum of energy of each phase. Active energy is obtained by accumulating the multiplication of voltage and current of each sample, which ensures the high accuracy of measure- ment ...
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... Input capture IC1 is used to detect if the A/D conversion is complete. After each conversion, a positive pulse the width of 4 clock cycles is outputted by the SDO pin of the MCP3909 device. IC1 is used to detect the falling edge of the pulse and generate an interrupt for every 2 falling edges, i.e., 1 data is read for every 2 conversions, thus realizing 6 ...
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... MCP3909 / dsPIC33F 3-Phase Energy Meter Reference Design The energy pulse processing program only begins when the level is close to outputting pulse level. To simplify the process and shorten the ISR execution time, a counter is used in place of the energy accumulation function for each pulse and to determine if a pulse will be outputted ...
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... All three MCP3909 devices use the same clock source and reset signal, so all 6 A/D channels of the 3 MCP3909 devices are synchronous. Only a single Data Ready (SDO) signal of any of the MCP3909 device is required to read A/D data of the 3 phases in turn. This module is invoked by IC1 interrupt triggered by the "data ready" signal on the SDO of the MCP3909 device ...
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... Reset the MCP3909 device through the RESET pin. The pin must be pulled low for no less than 1 clock cycle of the MCP3909 device • After the RESET pin is pulled high, wait for 4 clock cycles for the MCP3909 device pin functions to reset • Send Instruction 0x94 to the MCP3909 device through the SPI Interface • ...
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... Driven by a 3.2768 MHz clock. The MCP3909 device can generate 12.8 ksps of data output. Sampling input capture. An interrupt is generated for every two MCP3909 device samplings. 6.4 ksps sampling rate is realized. In fact, active power is cumulated at 6.4 ksps sampling rate (128 sampling points each cycle at 50 Hz), but other parameters are cumulated at 3 ...
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... MCP3909 / dsPIC33F 3-Phase Energy Meter Reference Design 3.8 DESCRIPTION OF PROJECT FILES TABLE 3-3: FILE DESCRIPTION File Name main.h Main program main.c global.h Mainly define important system macros, key data structures, and declare global variables. global.c MCP390x.h Declare macros, constants, local global variables, some of the global variables and functions used in the MCP390X device ...
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... The MCP3909 device’s current channel, CH0, contains a PGA with gain options 16. For high-accuracy energy meters, current ratio error needs to be segmented and calibrated for different current loads. The ratio error calibration of current channel uses a two-point calibration method ...
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... MCP3909 / dsPIC33F 3-Phase Energy Meter Reference Design 4.2.1 Current/Voltage Calibration Process The process of calibration is as follows: 1. Supply the meter with balanced load 1. Load the dsPIC33F with the proper correction factors. Automatically done using the PC software. See Chapter 5. “PC Software”. Repeat these following steps for the second point at 10% IB: 1 ...
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... When using two-point calibration, the compensation values of region 1 and 2 (0-0.075 I compensation values for region 3, 4 and 5 (0 are the same. B © 2009 Microchip Technology Inc. CURRENT REGIONS FOR PHASE CALIBRATION Current Range 0 - 0.075 I 0.075 I 0.2 I ...
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... MCP3909 / dsPIC33F 3-Phase Energy Meter Reference Design 4.4.1 Phase Lag Calibration Process The process of phase calibration is as follow: 1. Setup input condition: Phase A, voltage input 220V, current input is the current for region 1, voltage and current inputs of phase B and phase C are zero. 2. Load the dsPIC33F with the proper correction factors. This is automatically done using the PC software. See Chapter 5. “ ...
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... HDD space > • Microsoft Windows OS98 or later • Hardware COM interface 5.1.2 Installation 1. Unzip PM_Viewer setup.zip. 2. Double click on setup.exe. 3. Finish the installation according the prompt PM_Viewer.exe - Start -> Program -> Energy Meter ->PM_Viewer.exe. © 2009 Microchip Technology Inc. MCP3909 / DSPIC33F 3-PHASE DS51723A-page 43 ...
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... MCP3909 / dsPIC33F 3-Phase Energy Meter Reference Design 5.2 ESTABLISH COMMUNICATION 1. Open PM_Viewer. 2. Click on Comm Port selection, and select the com port (com1, com2, or com3) that you will use on the menu, noting the baud rate is 19200 bps in 1-8-1 format, and can not be changed. ...
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... BASIC PARAMETERS OUTPUT SCREEN FIGURE 5-2: 5.4 PHASE A/B/C HARMONIC OUTPUT SCREEN FIGURE 5-3: © 2009 Microchip Technology Inc. Basic Parameters Work Mode Screen. Phase N Harmonic Work Mode Screen. PC Software DS51723A-page 45 ...
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... MCP3909 / dsPIC33F 3-Phase Energy Meter Reference Design 5.5 DISTORTION RATE FIGURE 5-4: 5.6 HARMONIC POWER FIGURE 5-5: DS51723A-page 46 Distortion Mode Screen. Harmonic Power Work Mode Screen. © 2009 Microchip Technology Inc. ...
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... ENERGY ACCUMULATION FIGURE 5-6: 5.8 CALIBRATION STEP 1 - RESET ALL CALIBRATION 1. Select Reset All Calibration from the toolbar menu. 2. Meter Calibration Values are Reset. FIGURE 5-7: © 2009 Microchip Technology Inc. Energy Accumulation Work Mode Screen. Reset All Calibration Command. PC Software DS51723A-page 47 ...
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... MCP3909 / dsPIC33F 3-Phase Energy Meter Reference Design 5.9 LINEARITY CALIBRATION 1. Select Channel, either Voltage or Current. 2. Select Phase Select Region, either 100% or 10%. 4. Using a standard meter, supply the input conditions given here. 5. Enter the error recorded from the standard meter here. 6. Click the Set button. ...
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... Using a standard meter, supply the input conditions given here. 4. Click the Set Apparent button. 5. Enter the error recorded from the standard meter here. 6. Click the Set button. 7. Repeat steps 2-5 for the different regions. 8. Repeat for other 2 phases. © 2009 Microchip Technology Inc. PC Software DS51723A-page 49 ...
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... MCP3909 / dsPIC33F 3-Phase Energy Meter Reference Design 5.11 PHASE LAG CALIBRATION 1. Select Phase Select Region n. 3. Using a standard meter, supply the input conditions given here. 4. Enter the error recorded from the standard meter here. 5. Click the Set button. 6. Repeat steps 2-5 for the different regions. ...
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... Write Calibration Values to Meter Write Phase Lag Calibration Values to Meter Write Power Calibration Values to Meter Write Energy Pulse Configuration - Active/Apparent Reset All Calibration Values Write Energy Pulse Constant © 2009 Microchip Technology Inc. MCP3909 / DSPIC33F 3-PHASE COMMAND STRINGS Command Description Command 0x41 0x42 0x43 ...
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... MCP3909 / dsPIC33F 3-Phase Energy Meter Reference Design Variant-length frame structure is used and data communiate in bytes. The command protocol structure is defined as following. TABLE 6-2: START 2 Bytes • The START word has 2 bytes, which are 0x00, 0xFF ( PC to target board) or 0xFF, 0x00 (target board to PC) • ...
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... TABLE 6-7: Data Field Byte 1,2 3-6 7-10 94-98 © 2009 Microchip Technology Inc. Meter Communications Protocol METER RESPONSE, TOTAL REQUEST FRAME, DETAILED DESCRIPTION Name Status Frequency Phase A Voltage Phase B Voltage Phase C Voltage Phase A Current Phase B Current Phase C Current Neutral Current ...
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... MCP3909 / dsPIC33F 3-Phase Energy Meter Reference Design 6.4 STATUS REGISTER This register contains the gain register. REGISTER 6-1: STATUS REGISTER R-0 R-0 R-0 CPO VPO PHC_S1 bit 7 Legend Readable bit W = Writable bit -n = Value at POR ‘1’ = Bit is set bit 7 CPO: Current Phase Order ...
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... Total Harmonic Distortion of Phase C Voltage 13-16 Total Harmonic Distortion of Phase A Current 17-20 Total Harmonic Distortion of Phase B Current 21-24 Total Harmonic Distortion of Phase C Current © 2009 Microchip Technology Inc. Meter Communications Protocol HARMONIC ANALYSIS DETAILED DESCRIPTION Description PC TO METER (7 BYTES) Data Command ...
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... MCP3909 / dsPIC33F 3-Phase Energy Meter Reference Design 6.7 START ENERGY MEASUREMENT COMMAND TABLE 6-14: START 0xFF, 0x00 TABLE 6-15: START 0xFF, 0x00 TABLE 6-16: Data Field Byte 1-4 5-8 9-12 13-16 17-20 21-24 25-28 29-32 33-36 6.8 STOP ENERGY MEASUREMENT COMMAND ...
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... Harmonic Reactive Power Of Phase A 33-36 Harmonic Active Power Of Phase B 37-40 Harmonic Reactive Power Of Phase B 41-44 Harmonic Active Power Of Phase C 45-48 Harmonic Reactive Power Of Phase C © 2009 Microchip Technology Inc. Meter Communications Protocol PC TO METER (7 BYTES) Data Command Data Field Length 0x49 0x00 ...
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... MCP3909 / dsPIC33F 3-Phase Energy Meter Reference Design 6.10 CALIBRATE METER VOLTAGE/CURRENT COMMAND TABLE 6-22: START 0xFF, 0x00 TABLE 6-23: START 0xFF, 0x00 TABLE 6-24: Data Field Byte 1 Phase Select 2 Range Select 3 Channel Select 4-7 Correction Factor (Error Being Calibrated Out) DS51723A-page 58 ...
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... START 0xFF, 0x00 TABLE 6-30: Data Field Byte 1 Phase Select 2 Current Range Select 3-6 Correction Factor (Error Being Calibrated Out) © 2009 Microchip Technology Inc. Meter Communications Protocol PC TO METER (12 BYTES) Data Command Data Field Length 0x63 6 0x06 METER RESPONSE (7 BYTES) ...
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... MCP3909 / dsPIC33F 3-Phase Energy Meter Reference Design 6.13 CALIBRATE ENERGY PULSE COMMAND TABLE 6-31: START 0xFF, 0x00 TABLE 6-32: START 0xFF, 0x00 TABLE 6-33: Data Field Byte 1 Phase Select 2 Energy Output Mode 6.14 RESET ALL METER CALIBRATION VALUES COMMAND TABLE 6-34: ...
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... CALIBRATE METER CONSTANT (ENERGY PULSE OUTPUT CONSTANT) TABLE 6-37: START 0x00, 0xFF TABLE 6-38: START 0xFF, 0x00 TABLE 6-39: Data Field Byte 1-2 Energy Constant © 2009 Microchip Technology Inc. Meter Communications Protocol PC TO METER (9 BYTES) Data Command Data Field Length 0x67 2 0x02 METER RESPONSE (7 BYTES) Data ...
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... MCP3909 / dsPIC33F 3-Phase Energy Meter Reference Design NOTES: DS51723A-page 62 © 2009 Microchip Technology Inc. ...
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... ENERGY METER REFERENCE DESIGN Appendix A. Schematics and Layouts A.1 INTRODUCTION This appendix contains the following schematics and layouts for the MCP3909 / dsPIC33F 3-Phase Energy Meter Reference Design. • Power Supply Board Schematic • Main Board Schematic - Page 1 • Main Board Schematic - Page 2 • ...
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... MCP3909 / dsPIC33F 3-Phase Energy Meter Reference Design FIGURE A-2: POWER SUPPLY BOARD SCHEMATIC DS51723A-page 64 © 2009 Microchip Technology Inc. ...
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... FIGURE A-3: MAIN BOARD SCHEMATIC - PAGE 1 G1C G0C G1B G0B G1A G0A AD_CLK + + © 2009 Microchip Technology Inc. Schematics and Layouts + + + + DS51723A-page 65 ...
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... MCP3909 / dsPIC33F 3-Phase Energy Meter Reference Design FIGURE A-4: MAIN BOARD SCHEMATIC - PAGE 2 1 DS51723A-page 66 RD1 RF5 49 32 RD2 RF4 50 31 RD3 AN15/RB15 51 30 RD4 AN14/RB14 52 29 RD5 AN13/RB13 REF_V 53 28 RD6 AN12/RB12 Current_N 54 27 Current_N RD7 Vdd 55 26 3.3V Vddcore ...
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... FIGURE A-5: POWER SUPPLY BOARD LAYOUT - ASSEMBLY DRAWING © 2009 Microchip Technology Inc. Schematics and Layouts DS51723A-page 67 ...
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... MCP3909 / dsPIC33F 3-Phase Energy Meter Reference Design FIGURE A-6: POWER SUPPLY BOARD LAYOUT - COMPOSITE DRAWING DS51723A-page 68 © 2009 Microchip Technology Inc. ...
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... FIGURE A-7: MAIN BOARD LAYOUT - ASSEMBLY DRAWING © 2009 Microchip Technology Inc. Schematics and Layouts DS51723A-page 69 ...
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... MCP3909 / dsPIC33F 3-Phase Energy Meter Reference Design FIGURE A-8: MAIN BOARD LAYOUT - COMPOSITE DRAWING DS51723A-page 70 © 2009 Microchip Technology Inc. ...
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... JP6 CONN HOUSING 3POS .156 W/O RAMP Molex/Waldom 3 JP6 CONN TERM FEMALE 18-24AWG TIN 1 PCB RoHS Compliant Bare PCB, dsPIC33F and MCP3909 3-Phase Energy Meter (Power) Bottom Bd. 3 P4, P5, P6 CONN HOUS 3POS .100 W/RAMP/RIB (Connects to Above) 9 P4, P5, P6 CRIMP TERM FEMALE 22-30AWG TIN ...
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... MCP3909 / dsPIC33F 3-Phase Energy Meter Reference Design TABLE B-2: BILL OF MATERIALS - TOP BOARD Qty Reference 13 C100, C101, C102, CAP 1000PF 50V CERAMIC X7R C103, C104, C105, 0805 C106, C107, C108, C109, C110, C111, C112 6 C113, C114, C115, CAP CER 10UF 16V X7R 1206 ...
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... Technology Inc Microchip Technology Inc Microchip Technology Inc Xinge — Part Number 3051 GR005 3051 RD005 3051 BK005 B60 104-00159 ERJ-6ENF1001V ERJ-6ENF1000V ERJ-6ENF10R0V ERJ-6ENF20R0V ERJ-6GEYJ472V ERJ-6GEYJ471V 9C08052A4701FKHFT ERJ-6GEYJ511V ERJ-6ENF1002V TL1105BF250Q DIP-8-3.2768M HC-49S-SMD-7.3728M MCP1701T-5002I/MB MCP1700T-3302E/TT dsPIC33FJ128GP206 MAX3232CDR 24LC04B-E/SN MCP3909-I/SS MCP6002-I/SN SCT954F — DS51723A-page 73 ...
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... MCP3909 / dsPIC33F 3-Phase Energy Meter Reference Design NOTES: DS51723A-page 74 © 2009 Microchip Technology Inc. ...
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... For these types of meter designs, an external hardware PLL circuit is used to track power grid frequency, and the clock of the MCP3909 device is automatically updated to change the sampling frequency. Since the PLL output frequency drops behind the power grid frequency, a synchronous error exists in the system, and fully synchronous sampling is hard to achieve ...
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... MCP3909 / dsPIC33F 3-Phase Energy Meter Reference Design FIGURE C-1: C.2.1 Basic Idea of Quasi-Synchronous Sampling Assuming that the average of a periodic signal in one cycle is g(t), EQUATION C-1: ω Make then, EQUATION C-2: where f(x) = g(x/ If the entire period sampling cannot be realized while a sampling frequency deviation Δ ...
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... The quasi-synchronous recursive process mentioned above can be expressed as follows: For Equation C-4, the integral interval [x can be divided equally into sections, which results sampled data, ), (i=0,1,...,nxN), and we can iterate as follows: f(x i © 2009 Microchip Technology Inc. Power Calculation Theory β ∫ ...
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... MCP3909 / dsPIC33F 3-Phase Energy Meter Reference Design First iteration: Second iteration: DS51723A-page ∑ 1 ⋅ ρ ⋅ -------------- - ∑ ρ ∑ 1 ⋅ ρ ⋅ --------------- - ∑ ρ … × ∑ 1 ⋅ × --------------------------------- - – N × × ∑ ρ – i × – ∑ ⋅ ρ ⋅ ...
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... Third iteration: © 2009 Microchip Technology Inc. Power Calculation Theory N 1 ∑ 3 ⋅ ρ ⋅ 2 -------------- - ∑ ρ ∑ ⋅ ρ ⋅ --------------- - ∑ ρ … × – 1 ∑ 3 ⋅ × --------------------------------- - – N × – × ∑ ρ – i × – N … ρ ⋅ ...
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... MCP3909 / dsPIC33F 3-Phase Energy Meter Reference Design N-th iteration: Where ρ is the weight coefficient which is decided by the digital quadrature formula. i Complex rectangular quadrature algorithm or complex trapezoidal quadrature algorithm is usually used in quasi-synchronous sampling. Figure C-2 shows a 3-cycle interative process. Original data First Iteration ...
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... In Figure C-3, the red curve is the characteristic of the window function, and the blue curve is input signal, and the green curve is the output signal. FIGURE C-3: Processing. © 2009 Microchip Technology Inc. Power Calculation Theory 1 ⋅ η ...
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... MCP3909 / dsPIC33F 3-Phase Energy Meter Reference Design C.3 THE HARMONIC ANALYSIS ALGORITHM OF QUASI-SYNCHRONOUS SAMPLING Periodic signal can be expressed as trigonometric Fourier series or exponential Fourier series. A periodic signal with a period of T can be expressed as : EQUATION C-11: where: EQUATION C-12: EQUATION C-13: or as: EQUATION C-14: ...
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... Make g(t) = f(t) • cos(K•ω•t), it can be proved that g(t) is also a periondic function with T as its period. Averaging g(t) in the range results in: EQUATION C-19 × g(t). Therefore EQUATION C-20: EQUATION C-21: Where N, n and η EQUATION C-22: EQUATION C-23: Where: EQUATION C-24: © 2009 Microchip Technology Inc. Power Calculation Theory ϕ cos ∫ ...
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... MCP3909 / dsPIC33F 3-Phase Energy Meter Reference Design C.4 MEASURING THE VOLTAGE/CURRENT RMS VALUE AND POWER USING QUASI-SYNCHRONOUS SAMPLING ALGORITHM From Equation C-11, a periodic voltage can be expressed as: EQUATION C-25: So the voltage fundamental and the voltage of each harmonic can be expressed as: EQUATION C-26: From Equation C-25, the fundamental voltage and voltage of each harmonic can also ...
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... Similarly, the effective values and initial phase angles of fundamental current and current of each other harmonic can be expressed as: EQUATION C-34: EQUATION C-35: The relationship between i EQUATION C-36: EQUATION C-37: Total current RMS can be expressed as: EQUATION C-38: © 2009 Microchip Technology Inc. Power Calculation Theory , u and U can be expressed as ⋅ ...
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... MCP3909 / dsPIC33F 3-Phase Energy Meter Reference Design According to the definition of power measurement, the active power and reactive power of the fundamental and each other harmonic can be expressed as: EQUATION C-39: EQUATION C-40: Substituting Equation C-31, C-32, C-33 and C-37 into Equation C-39 and C-40, the ...
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... If the frequency f Δf << f, then from Equation C-27, the fundamental signal can be expressed as: EQUATION C-45: If: EQUATION C-46: EQUATION C-47: EQUATION C-48: © 2009 Microchip Technology Inc. Power Calculation Theory to be measured is known definite value f, i.e ω ⋅ ϕ ...
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... MCP3909 / dsPIC33F 3-Phase Energy Meter Reference Design We get: EQUATION C-49: EQUATION C-50: As Δf << f, from Equation C-49 and C-50, we have: EQUATION C-51: Therefore, EQUATION C-52: Assuming that the signal's initial phase angle measured in the 1st cycle is ϕ the N- then the difference between actual frequency and the assumed ...
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... Also, when the input frequency is around the multiple of cycle frequencies (52.459 Hz, 51.613 Hz, 50.794 Hz, 50.0 Hz, 49.231 Hz, 48.485 Hz and 47.761 Hz), the calculateion error is © 2009 Microchip Technology Inc. Power Calculation Theory Quasi-sync Algorithm Error Analysis of 3 Iterations. ...
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... MCP3909 / dsPIC33F 3-Phase Energy Meter Reference Design minimal (<0.01%). When the input frequency deviates from the multiple of cycle frequencies, the calculation error increases rapidly. As the calculation error is related to the frequency offset to the multiple of freqency point, the calculation error caused by frequency offset can be corrected. Figure C-6 is the error analysis after frequency off- set correction using simple parabolic interpolation ...
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... APPARENT POWER OF EACH PHASE AND TOTAL APPARENT POWER Apparent power is defined as: EQUATION C-56: C.9 POWER FACTOR OF EACH PHASE AND TOTAL POWER FACTOR Power factor is defined as the ratio of active power to apparent power. The definition can be represented as shown in Equation C-57: EQUATION C-57: © 2009 Microchip Technology Inc. Power Calculation Theory ...
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... MCP3909 / dsPIC33F 3-Phase Energy Meter Reference Design C.10 Active Energy AND REACTIVE ENERGY Active energy is defined as the integral of active power over time, which is: EQUATION C-58: In this design, active energy is obtained from multiplying the voltage by the current sampled each time. The phase angle difference is compensated after each power measurement is completed ...
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... A－有功电能；R—无功电能；R A－有功电能；R—无功电能；R A－有功电能；R—无功电能；R FIGURE C-7: © 2009 Microchip Technology Inc. Power Calculation Theory Reactive in (+R) Reactive in (+R) ...
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... MCP3909 / dsPIC33F 3-Phase Energy Meter Reference Design C.12 HARMONIC COMPONENTS OF CURRENT, VOLTAGE AND TOTAL HARMONIC DISTORTION In Section C.3 “The Harmonic Analysis Algorithm Of Quasi-synchronous Sam- pling”, we discussed the measuring of current and voltage signals for each order of harmonics. 3 parameters are used to show to what extent a distorted wave deviates from a sine wave ...
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... Rated Current (%) 50 120 © 2009 Microchip Technology Inc. Power Calculation Theory ε δ ⋅ – ------------------------ - f = 100 I 1 the rated current ratio the primary current the secondary current that passes I ...
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... MCP3909 / dsPIC33F 3-Phase Energy Meter Reference Design C.14 RELATIONSHIP BETWEEN ERROR AND CURRENT For a given load and frequency, the absolute ratio error and angle error increase when the primary current decreases from the rated value for un-compensated current trans- former. The reason is that with the decrease of the secondary current, the magnetic permeability µ ...
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... Since current has a large dynamic range, for a meter which requires high accuracy (0.2s and 0.5s), the multi-point calibration method is needed to meet input requirement for full range. The MCP3909 device's current channel includes an adjustable gain amplifier. The ratio error must be recalibrated for different amplification, but only needs to be calibrated once under the same amplification conditions. © ...
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... MCP3909 / dsPIC33F 3-Phase Energy Meter Reference Design C.16 PHASE LAG COMPENSATION Phase lag has no effect on the metering of RMS current/voltage and apparent power, but will affect the metering of power, since the phase lag will change the phase relationship between the input current and the voltage. This will result in a deviation of the calculated active power from the calculated reactive power ...
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... The error can be obtained from the output of the meter calibration workbench. EQUATION C-73: © 2009 Microchip Technology Inc. Power Calculation Theory ⋅ ⋅ φ ...
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... MCP3909 / dsPIC33F 3-Phase Energy Meter Reference Design Since the phase lag of a CT's output signal is related to the magnitude of current, different correction coefficients, K, can be set according to different RMS current values. In this design, 5 calibration points can be set does not require high-preci- sion, fewer points can be set to simplify calibration. ...
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... To avoid complexity in calculation and to maximize the correction precision, the following equations may be used to approximate K small. EQUATION C-80: EQUATION C-81: © 2009 Microchip Technology Inc. Power Calculation Theory and Δ Δϕ ≈ Δϕ ⋅ Δϕ ----- - sin k' = cos cos – ...
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... MCP3909 / dsPIC33F 3-Phase Energy Meter Reference Design NOTES: DS51723A-page 102 © 2009 Microchip Technology Inc. ...
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... This is provided for download from Microchip’s website, file names and checksums below. At the same time you need to change the crystal to provide clock for metering IC. TABLE D-1: Line Frequency © 2009 Microchip Technology Inc. MCP3909 / DSPIC33F 3-PHASE FIRMWARE FILES Firmware Name Hex File Checksum PM_1_50.ZIP PM_1_60.ZIP YXX VALUE TBD 3 ...
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... Fax: 886-3-6578-370 Taiwan - Kaohsiung Tel: 886-7-536-4818 Fax: 886-7-536-4803 Taiwan - Taipei Tel: 886-2-2500-6610 Fax: 886-2-2508-0102 Thailand - Bangkok Tel: 66-2-694-1351 Fax: 66-2-694-1350 © 2009 Microchip Technology Inc. EUROPE Austria - Wels Tel: 43-7242-2244-39 Fax: 43-7242-2244-393 Denmark - Copenhagen Tel: 45-4450-2828 Fax: 45-4485-2829 France - Paris Tel: 33-1-69-53-63-20 ...