Explore chapters and articles related to this topic
Evolving Power System Technologies and Considerations
Published in Dale R. Patrick, Stephen W. Fardo, Brian W. Fardo, Electrical Power Systems Technology, 2021
Dale R. Patrick, Stephen W. Fardo, Brian W. Fardo
Most of the electrical power that is produced is alternating current (AC) power. Three-phase alternators are used to produce AC power at electrical power plants. DC power can be produced by chemical action or rotating machinery or it can be converted from AC sources by the process of rectification. Certain types of alternative power systems produce DC power that may be converted to AC.
Introduction—Electricity’s Attributes
Published in Clark W. Gellings, 2 Emissions with Electricity, 2020
Alternating current (AC) power distribution is generally at frequencies of 50 or 60 Hz. It is the frequency used to generate, transmit, distribute, and utilize power in modern power systems.* These frequencies also embody the utilization of the largest overall use of electricity—the electric motor.
Fuel Cells
Published in Michael F. Hordeski, Emergency and Backup Power Sources:, 2020
The fuel cell produces a direct current (DC) output. Alternating current (AC) power is obtained from an inverter, which converts DC voltage to AC. Inverters are also used in generating units that produce electricity directly from sunlight using solar photovoltaic panels and from the wind using wind-driven turbine generators.
Novel Three-Port Inverter Outputting Two Sinusoidal AC Voltages
Published in Electric Power Components and Systems, 2018
Hurng-Liahng Jou, Jinn-Chang Wu, Kune-Der Wu, Ding-Feng Huang
The system frequency for AC power systems is 50 Hz, 60 Hz or 400 Hz [10, 11]. 50 Hz or 60 Hz power systems are used in the utility power systems and 400 Hz power systems are used in aircraft, spacecraft, submarines, communications, and marine vessels. Some power equipment can use an AC voltage with a frequency of 50 Hz or 60 Hz, but others can only use a specific AC voltage of 50 Hz or 60 Hz. A conventional DC–AC converter outputs a sinusoidal voltage with only one frequency. The flexibility of its application is increased if a DC–AC converter simultaneously outputs two sinusoidal voltages with frequencies of both 50 Hz and 60 Hz. Norihiro Asahi et al. propose a DC–AC converter outputs two AC sinusoidal voltages with different frequencies [12]. However, the DC capacitors connected in series are required. This topology has the disadvantage that the exact control for the voltages of three capacitors is complicated. In [13] and [14], the matrix converter with dual outputs is proposed for driving two three-phase motors where two output stages are connected in parallel and one power electronic leg is shared for both output stages to simplify the power circuit. However, the controls for both output stages are independent. In [15] and [16], a dual-output DC–AC inverter is developed where two output stages are connected in series and one power electronic switch is shared in each power electronic leg to simplify the power circuit. The dual-output DC–AC inverter is composed of nine power electronic switches for dual three-phase outputs and is configured by six power electronic switches for dual single-phase outputs. However, the DC bus voltage should be higher than the summation of peak voltages of dual outputs and all of the power electronic switches should withstand the full DC bus voltage. In addition, the above topologies for power converter with dual outputs cannot adopt multi-level power converter to reduce the power loss, EMI, and the switching harmonics.
Design and Development of a B-Type Inverter for Harmonic Mitigation in a Grid Integrated System Using Whale Optimization Algorithm
Published in Electric Power Components and Systems, 2023
Devesh Raj, Thiyagarajan Venkatraman, Muthuselvan Balasubramanian, Dishore Shunmugham Vanaja
Conventional energy sources like fossil fuel, petroleum, natural gas discharge harmful gasses like freons, chloro-fluoro carbons (CFCS), hydrofluorocarbons (HFCs) when used as fuel in the generating stations. These harmful gases lead to climatic changes and global warming. Moreover, the conventional energy sources are commercial in nature. The growing demand of electrical energy can be controlled by replacing the nonrenewable energy sources with renewable energy sources such as solar, wind, tidal, biomass. The power obtained from most of the renewable energy systems are in the form of DC, whereas the transmission system and loads use the AC power. Hence a power converter has to be implemented for transforming the DC power to AC power. Inverters are the prominent devices used for conversion of power from DC to AC. For high power applications the traditional inverter switches cannot withstand high voltages. Therefore, Multilevel inverters were developed by the researchers for operating at higher voltages with less THD. Multilevel inverters have gained more interest for the researchers with the up gradation of modern power electronics technology. Many researchers are developing novel structures, control techniques for improving the inverters performance globally. Multilevel inverters are classified as the diode clamped or neutral point clamped (NPCMLI), flying capacitor clamped (FCMLI) and the cascaded H-bridge multilevel inverter (CHBMLI) [1–3]. The drawback in both (NPCMLI & FCMLI) the topologies are excessive usage of diodes and flying capacitors for obtaining more levels. Moreover, the controls of both the inverters are complicated. The authors in [4] proposed the cascaded structure of multilevel inverter. This structure uses only symmetric (equal) voltage sources for each H bridge unit. Finally, in [5] the authors proposed the asymmetric CHBMLI which uses unequal dc sources for producing high level of output voltages. These symmetric and asymmetric topologies use fewer components for achieving higher voltage levels . Soft switching is also possible in these topologies. Therefore, the cascaded multilevel inverters (CMLI) are preferred for most of the multilevel applications. The major limitation of the conventional multilevel inverter is the increase in the number of switches as the number of levels increases. The increase in switch count further leads to increase in the circuit complexity. In addition, complex switching pulse generation, DC losses, huge circuit layout, difficult to control techniques, more installation space, other supporting components such as heat sink, cables, driver circuit’s requirements and high input port controller to generate the pulses, and finally cost of the inverter are increasing drastically. Many researches on reducing the components of multilevel inverters are going on from the past few years and many reduced multilevel structures have been developed. Most of the existing 7-level reduced switch multilevel inverter structures are presented in Table 1. Various transformer less 7-level inverter topologies with advanced pulse width modulation methods are discussed in [11–15]. There are few drawbacks like excessive usage of diodes and capacitors. Moreover, the device count of few topologies is much than the existing topologies.