Abstract
Background: A multifunctional power factor device based on the FFT algorithm has
been designed. The digital panel can display power factor, voltage, current, frequency, phase angle,
active power and reactive power.
Objective: To solve the influence of the harmonic interference and the aperiodic component on the
accuracy of power factor measurement.
Methods: In this paper, by combining a fixed-point 256-point FFT algorithm and taking STM32 as
the core microcontroller, the hardware circuit and the software program are designed respectively.
The hardware circuit is tested and analyzed in practice. Among them, the hardware circuit mainly
includes the main circuit design, STM32 control circuit design, EMI and second-order RC filter
circuit design, sampling circuit design, and signal conditioning circuit design. The software program
mainly includes the main program, AD conversion subroutine, voltage and current acquisition
subroutine, LCD display subroutine and twirl factor array. FFT algorithm is achieved by the
table look-up method.
Results: Finally, the hardware circuit is built and the software program is debugged to test the designed
device. The experimental results show that the designed power factor instrument meets the
task requirements under the different types of loads.
Conclusion: After processing and analyzing the measurement results, it can be concluded that: under
the pure resistive load, the maximal relative error of electrical parameters is 4.49%; and under
the resistive inductive load, the maximal relative error of electrical parameters is 2.86%. Both results
meet the design requirements.
Keywords:
Power factor device, FFT algorithm, second-order RC filtering, signal conditioning circuit, aperiodic component,
STM32.
Graphical Abstract
[2]
W. Tang, and W. Zhong, "Design and implementation of intelligent power saving device based on power factor compensation", Electron. Test, vol. 16, pp. 14-15, 2018.
[3]
S. Powniker, and S. Shelar, "Development of active power factor correction controller using boost converter", , In: 2016 IEEE International WIE Conference on Electrical and Computer Engineering, Pune, India, 2017, pp. 212-216.,
[4]
X. Guo, Z. Yang, Z. Wu, H. Feng, and Z. Liu, "Theoretical study on single phase power factor rectifier", Jisuanji Celiang Yu Kongzhi, vol. 26, no. 3, pp. 171-175, 2018.
[5]
Y. Meng, M. Chong, and S. Wang, "Research of a high-precision zero-crossing detection method with phase compensation function", Dianzi Qijian, vol. 39, no. 2, pp. 398-402, 2016.
[6]
Y. Zhang, and N. Wang, "Measuring algorithm for power frequency factor based on general harmonic wavelet", China Measure. Test., vol. 42, no. 1, pp. 16-20, 2016.
[7]
P.P. Machado, T.P. Abud, M.Z. Fortes, and B.S.M.C. Borba, "Power factor metering system using Arduino", In 2017 IEEE Workshop on Power Electronics and Power Quality Applications, 2017 Bogota, Colombia, pp. 1-6.,
[8]
J. Jia, H. Yi, X. Xia, J. Li, Y. Wu, and B. Xia, "Distributed energy power system access new metering system", Power Syst. Protect. Cont., vol. 45, no. 3, pp. 118-124, 2017.
[12]
X. Gao, and X. Wang, "Design and calibration of power parameters measurement instrument with CS5463", China Measure. Testing Technol., vol. 39, no. 1, pp. 76-79, 2013.
[13]
P. Yadav, and L.M. Saini, "Three phase power metering using MAXQ3183", In: 2017 Recent Developments in Control Automation & Power Engineering, Noida, India, 2017, pp. 286-290..
[14]
W. Hou, and C. Gu, "Design and simulation of two-order voltage source low pass active filter circuit controlled by voltage", In: Experimental Technol. Manage., vol. 10, pp. 103-106, 2014..