Nobile Giovanni, Cacciato Mario, Vasta Ester
Independent Researcher, 97100 Ragusa, Italy.
Department of Electrical, Electronics Engineering and Computer Science (DIEEI), University of Catania, 95100 Catania, Italy.
Sensors (Basel). 2022 May 5;22(9):3517. doi: 10.3390/s22093517.
The traditional approach to calculate the active and reactive power in AC power systems requires the measurement of the phase shift between the voltage and current for the evaluation of the power factor. To do this, power analyzers can implement several methods. In principle, it is always necessary to identify specific points of waveforms (e.g., using a zero-crossing detection technique) and get their time shift. In a similar way, the frequency value must be evaluated in order to calculate the angular frequency. Unfortunately, this kind of common method exhibits some issues, such as the large sensitivity to noise. Moreover, inaccuracies in the evaluation of the power factor have a big impact on the final estimation of the electric power. This paper presents a simple but effective way to calculate the electric power, overcoming the need for a direct measurement of the phase shift and frequency. In particular, it is shown that the active power can be easily calculated as the difference between the peak value of the instantaneous power and apparent power. The reactive power and power factor are evaluated by exploiting the same quantities. The practical implementation of the proposed formulation in power analyzers guarantees several benefits without reducing accuracy.
在交流电力系统中，计算有功功率和无功功率的传统方法需要测量电压和电流之间的相位差，以便评估功率因数。为此，功率分析仪可以采用多种方法。原则上，总是需要识别波形的特定点（例如，使用过零检测技术）并获取它们的时间偏移。类似地，为了计算角频率，必须评估频率值。不幸的是，这种常见方法存在一些问题，例如对噪声的高灵敏度。此外，功率因数评估中的不准确对电力的最终估计有很大影响。本文提出了一种简单而有效的计算电功率的方法，克服了直接测量相位差和频率的需求。特别是，结果表明有功功率可以很容易地计算为瞬时功率峰值与视在功率之间的差值。无功功率和功率因数通过利用相同的量来评估。在功率分析仪中对所提出公式的实际实现保证了若干优点而不降低精度。
