TIDUF27A February   2025  – March 2025 AMC131M03 , MSPM0G1507

 

  1.   1
  2.   Description
  3.   Resources
  4.   Features
  5.   Applications
  6.   6
  7. 1System Description
    1. 1.1 Key System Specifications
    2. 1.2 End Equipment
    3. 1.3 Electricity Meter
    4. 1.4 Power Quality Meter, Power Quality Analyzer
  8. 2System Overview
    1. 2.1 Block Diagram
    2. 2.2 Design Considerations
      1. 2.2.1 Voltage Measurement Analog Front End
      2. 2.2.2 Analog Front End for Current Measurement
      3. 2.2.3 XDS110 Emulator
      4. 2.2.4 Bluetooth® Data Transmission
      5. 2.2.5 Bluetooth® Connection Between Two Modules
      6. 2.2.6 Bluetooth® to UART Connection
      7. 2.2.7 Magnetic Tamper Detection With TMAG5273 Linear 3D Hall-Effect Sensor
    3. 2.3 Highlighted Products
      1. 2.3.1  MSPM0G3507
      2. 2.3.2  AMC131M03
      3. 2.3.3  CDC6C
      4. 2.3.4  RES60A-Q1
      5. 2.3.5  TPS3702
      6. 2.3.6  TPD4E05U06
      7. 2.3.7  ISOUSB111
      8. 2.3.8  LMK1C1104
      9. 2.3.9  MSP432E401Y
      10. 2.3.10 TPS709
      11. 2.3.11 TMAG5273
  9. 3Hardware, Software, Testing Requirements, and Test Results
    1. 3.1 Hardware Requirements
      1. 3.1.1 Clocking System
        1. 3.1.1.1 BAW Oscillator
        2. 3.1.1.2 Crystal Oscillator
        3. 3.1.1.3 PWM
        4. 3.1.1.4 Clock Buffers
      2. 3.1.2 SPI Bus Configuration
      3. 3.1.3 Jumper Settings for LED and UART
    2. 3.2 Software Requirements
      1. 3.2.1 UART for PC GUI Communication
      2. 3.2.2 Direct Memory Access (DMA)
      3. 3.2.3 ADC Setup
      4. 3.2.4 Calibration
    3. 3.3 Test Setup
      1. 3.3.1 Connections to the Test Setup
      2. 3.3.2 Power Supply Options and Jumper Settings
        1.       51
      3. 3.3.3 Cautions and Warnings
    4. 3.4 Test Results
      1. 3.4.1 Electricity Meter Metrology Accuracy Results
      2. 3.4.2 Radiated Emissions Performance
  10. 4Design and Documentation Support
    1. 4.1 Design Files
      1. 4.1.1 Schematics
      2. 4.1.2 BOM
      3. 4.1.3 PCB Layout Recommendations
        1. 4.1.3.1 Layout Prints
    2. 4.2 Tools and Software
    3. 4.3 Documentation Support
    4. 4.4 Support Resources
    5. 4.5 Trademarks
  11. 5About the Author
  12. 6Revision History

3.4.1 Electricity Meter Metrology Accuracy Results

To test for metrology accuracy in the electricity meter configuration, a source generator is used to provide the voltages and currents to TIDA-010244. In this design, a nominal voltage of 120V between the three phases and neutral, calibration current of 10A, and nominal frequency of 60Hz are used for each of the three phases, while phase calibration is done at 60°.

In the cumulative active and reactive energy testing, the sum of the energy reading of each phase is tested for accuracy. For cumulative active energy error and cumulative reactive energy error testing, current is varied from 100mA to 100A. For cumulative active energy, a phase shift of 0° (PF = 1), PF = 0.5i (inductive), and PF = 0.8c (capacitive) is applied between the voltage and current waveforms fed to the reference design. Based on the error from the active energy output pulse, a plot of active energy % error versus current is created for the three PF values.

For cumulative reactive energy error testing, a similar process is followed except that a phase shift of 90° (sin ϕ = 1i), sin ϕ = 0.5i (inductive), and sin ϕ = 0.8c (capacitive) are used, and cumulative reactive energy error is plotted.

All these tests were run using the 4ksps sample rate setting of the AMC131M03.

For the VRMS accuracy test on Phase A, the voltage was varied from 10V to 270V while current was held steady at 10A. For the IRMS accuracy test on Phase A, the voltage was kept steady at 120V, while current was varied from 0.025A to 100A.

The following two plots for Active and Reactive Power are per IEC 62053-22 limits for class 0.2S and 0.5S accuracy, assuming Inominal = 15A; hence, the 5% point of Inominal is at 750mA.

The average error for each measurement is calculated from five test series, taken sequentially for each current value, and the maximum deviation from these five measurements is calculated (not shown in the following plots) to confirm the stability of this metrology subsystem being below 10% of the maximum error allowed.

For the following test results, gain, phase, and offset calibration are applied to the meter. At higher currents, the % error shown is dominated by shunt resistance drift caused by the increased heat generated at high currents.

The test data are recorded with calibrated value data of:

  • V_in =120V
  • I_in = 10A
  • Phase calibrated at 60°
  • Phases = 3
  • Energy Pulses for ACT and REACT = 6400
  • Room temperature
Table 3-3 Active Energy % Error Versus Current, 200µΩ Shunts
CURRENT (A) AVG ERROR %
PF = 1,
cos ϕ = 0°		 LIMIT (%)
[CLASS 0.2]
IEC 62053-22
(PF 0.5i/0.8c)		 LIMIT (%)
[CLASS 0.5]
IEC 62053-22
(PF 0.5i/0.8c)		 AVG ERROR %
PF = 0.5i,
cos ϕ = 60°		 LIMIT (%)
[CLASS 0.2]
IEC 62053-22
(PF 0.5i/0.8c)		 LIMIT (%)
[CLASS 0.5]
IEC 62053-22
(PF 0.5i/0.8c)		 AVG ERROR %
PF = 0.8c,
cos ϕ = –36.87°
0,1 0,05 0,4 1 –0,0062 0,5 1 0,0844
0,5 0,022 0,4 1 0,0088 0,5 1 0,052
0,75 0,019 0,4 1 –0,0044 0,5 1 0,0484
1,5 0,014 0,2 0,5 –0,0126 0,3 0,6 0,044
3 0,016 0,2 0,5 –0,016 0,3 0,6 0,0522
7,5 0,008 0,2 0,5 –0,0488 0,3 0,6 0,0546
15 –0,006 0,2 0,5 –0,0556 0,3 0,6 0,0368
30 –0,013 0,2 0,5 0,0116 0,3 0,6 0,0154
60 –0,037 0,2 0,5 –0,0398 0,3 0,6 –0,018
75 –0,082 0,2 0,5 –0,1036 0,3 0,6 –0,058
100 –0,096 0,2 0,5 –0,2234 0,3 0,6 –0,118
TIDA-010244 Active Energy % Error Figure 3-3 Active Energy % Error
Table 3-4 Reactive Energy % Error Versus Current, 200µΩ Shunts
CURRENT AVG ERROR %
sin ϕ = 1i (90°)		 LIMIT (%)
[CLASS 1]		 Limit (%)
[CLASS 0.5]		 AVG ERROR %
sin ϕ = 0.5i (30°)		 Limit (%)
[CLASS 1]		 Limit (%)
[CLASS 0.5]		 AVG ERROR %
sin ϕ = 0.8c (–53.13°)
0,1 –4,6028 –9,0318 6,3002
0,5 –0,8614 3 2 –1,6634 1,3914
0,75 –0,5374 3 2 –1,0236 0,9742
1,5 –0,2142 2 1 –0,4482 3 2 0,543
3 –0,0452 2 1 –0,1348 2 1 0,334
7,5 0,0504 2 1 0,0656 2 1 0,194
15 0,0796 2 1 0,112 2 1 0,1502
30 0,1006 2 1 0,1416 2 1 0,1354
60 0,0904 2 1 0,1272 2 1 0,1026
75 0,0608 2 1 0,1004 2 1 0,0746
100 –0,0642 2 1 0,0532 2 1 –0,0596
TIDA-010244 Reactive % Energy Error (3 phases) Figure 3-4 Reactive % Energy Error (3 phases)
Table 3-5 Current RMS % Error at 120V, 200µΩ Shunts
CURRENT (A) PHASE A PHASE B PHASE C
% DIFF % DIFF % DIFF
0,025 –3,583 –2,67 –6,677
0,05 –1,306 –1,051 –2,144
0,1 –0,382 –0,35 –0,268
0,25 –0,076 –0,097 –0,095
0,5 –0,021 –0,06 –0,013
1 –0,025 –0,109 –0,014
2 –0,01 –0,066 0,0025
5 –0,04 –0,093 0,0098
10 –0,051 –0,095 –0,021
20 –0,038 –0,075 0,011
30 –0,038 –0,072 0,01
40 –0,01 –0,055 –0,002
50 0,0114 –0,07 0,0006
60 –0,021 –0,071 0,0157
70 –0,015 –0,032 0,0353
80 0,0007 0,008 0,0733
90 0,03 0,063 0,0974
100 0,0462 0,05 0,0648

Here the plot for the current errors of all 3 phases:

TIDA-010244 Current RMS % Error at 120V, 200µΩ Shunts for Phases A, B and C Figure 3-5 Current RMS % Error at 120V, 200µΩ Shunts for Phases A, B and C
Table 3-6 Voltage RMS % Error at 10A, 200µΩ Shunts
VOLTAGE (V) PHASE A PHASE B PHASE C
% DIFF % DIFF % DIFF
9 0,088 0,0856 0,0633
10 0,097 0,05 0,06
30 0,093 0,0463 0,043
50 0,031 0,0238 0,0178
70 0,03 0,0027 0,0084
90 0,022 0,0059 –0,006
100 0,073 –0,013 –0,016
120 –0,013 –0,014 –0,026
140 –0,047 –0,05 –0,021
160 –0,054 –0,066 –0,05
180 –0,046 –0,069 –0,071
200 –0,07 –0,089 –0,063
220 –0,098 –0,107 –0,089
230 –0,097 –0,112 –0,096
240 –0,084 –0,108 –0,1
260 –0,137 –0,126 –0,118
270 –0,13 –0,138 –0,138

Here is the combined plot for all 3 phases:

TIDA-010244 Voltage RMS % Error at 10A, 200µΩ Shunts for Phases A, B, and C Figure 3-6 Voltage RMS % Error at 10A, 200µΩ Shunts for Phases A, B, and C