TIDUF27A February 2025 – March 2025 AMC131M03 , MSPM0G1507
- 1
- Description
- Resources
- Features
- Applications
- 6
- 1System Description
-
2System Overview
- 2.1 Block Diagram
- 2.2
Design Considerations
- 2.2.1 Voltage Measurement Analog Front End
- 2.2.2 Analog Front End for Current Measurement
- 2.2.3 XDS110 Emulator
- 2.2.4 Bluetooth? Data Transmission
- 2.2.5 Bluetooth? Connection Between Two Modules
- 2.2.6 Bluetooth? to UART Connection
- 2.2.7 Magnetic Tamper Detection With TMAG5273 Linear 3D Hall-Effect Sensor
- 2.3 Highlighted Products
- 3Hardware, Software, Testing Requirements, and Test Results
- 4Design and Documentation Support
- 5About the Author
- 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 ? = 1i), sin ? = 0.5i (inductive), and sin ? = 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
| CURRENT (A) | AVG ERROR % PF = 1, cos ? = 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 ? = 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 ? = –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 |
Figure 3-3 Active Energy % Error| CURRENT | AVG ERROR % sin ? = 1i (90°) |
LIMIT (%) [CLASS 1] |
Limit (%) [CLASS 0.5] |
AVG ERROR % sin ? = 0.5i (30°) |
Limit (%) [CLASS 1] |
Limit (%) [CLASS 0.5] |
AVG ERROR % sin ? = 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 |
Figure 3-4 Reactive % Energy Error (3
phases)| 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:
Figure 3-5 Current RMS % Error at 120V,
200μ? Shunts for Phases A, B and C| 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:
Figure 3-6 Voltage RMS % Error at 10A,
200μ? Shunts for Phases A, B, and C