China 
Africa 
Explore chapters and articles related to this topic
Mitigation Techniques
Published in L. Ashok Kumar, S. Albert Alexander, Computational Paradigm Techniques for Enhancing Electric Power Quality, 2018
L. Ashok Kumar, S. Albert Alexander
Harmonic number (h) refers to the individual frequency elements that comprise a composite waveform. For example, h = 5 refers to the fifth harmonic component with a frequency equal to five times the fundamental frequency. If the fundamental frequency is 60 Hz, then the fifth harmonic frequency is 5 × 60, or 300 Hz. The harmonic number 6 is a component with a frequency of 360 Hz. Dealing with harmonic numbers and not with harmonic frequencies is done for two reasons. The fundamental frequency varies among individual countries and applications. The fundamental frequency in the U.S. is 60 Hz, whereas in Europe and many Asian countries it is 50 Hz. Also, some applications use frequencies other than 50 or 60 Hz; for example, 400 Hz is a common frequency in the aerospace industry, while some AC systems for electric traction use 25 Hz as the frequency. The inverter part of an AC ASD can operate at any frequency between zero and its full rated maximum frequency, and the fundamental frequency then becomes the frequency at which the motor is operating. The use of harmonic numbers allows us to simplify how we express harmonics. The second reason for using harmonic numbers is the simplification realized in performing mathematical operations involving harmonics.
4 Harmonics
Published in C. Sankaran, Power Quality, 2017
Harmonic number (h) refers to the individual frequency elements that comprise a composite waveform. For example, h = 5 refers to the fifth harmonic component with a frequency equal to five times the fundamental frequency. If the fundamental frequency is 60 Hz, then the fifth harmonic frequency is 5 × 60, or 300 Hz. The harmonic number 6 is a component with a frequency of 360 Hz. Dealing with harmonic numbers and not with harmonic frequencies is done for two reasons. The fundamental frequency varies among individual countries and applications. The fundamental frequency in the U.S. is 60 Hz, whereas in Europe and many Asian countries it is 50 Hz. Also, some applications use frequencies other than 50 or 60 Hz; for example, 400 Hz is a common frequency in the aerospace industry, while some AC systems for electric traction use 25 Hz as the frequency. The inverter part of an AC adjustable speed drive can operate at any frequency between zero and its full rated maximum frequency, and the fundamental frequency then becomes the frequency at which the motor is operating. The use of harmonic numbers allows us to simplify how we express harmonics. The second reason for using harmonic numbers is the simplification realized in performing mathematical operations involving harmonics.
High-Efficiency Power Amplifiers
Published in Choi Jung Han, Iniewski Krzysztof, High-Speed and Lower Power Technologies, 2018
Guillermo Velasco-Quesada, Herminio Martínez‑García, Alfonso Conesa-Roca
Along with a high power conversion efficiency, a low percentage of distortion is obtained. Indeed, with a well-balanced push-pull amplifier, the even harmonic distortion components will cancel out, leaving only the odd-numbered harmonics. Since the amplitude of the different harmonics decreases rapidly with increasing harmonic number, the cancellation of the second harmonic term, which will be the largest harmonic component, along with the other even harmonics, can lead to a very great reduction in the distortion.
A new multivariate control chart based on the isolation forest algorithm
Published in Quality Engineering, 2023
Anomaly Score. The average path length of all n nodes on the trees, c(n), is computed by the following equation: where H(i) is the harmonic number and can be estimated as ln(i)+0.5772156649 (Euler’s constant). The height is related to the sample itself and the sampled subset. Here, the range of the height of samples is normalized and mapped between 0 and 1. Then, the anomaly score is computed as follows: where n is the number of training samples and is the average value of a collection of isolation trees (there is one h(x) value in one iTree). According to Eq. [3]: when when when