Inversion is the change of dc power to ac power at a desired output voltage or current and frequency. A static semiconductor inverter circuit does this electrical energy inverting transformation. The terms voltage-fed and current-fed are used in relation with the output from inverter circuits. Conventionally, inverters are classified into two broad categories – voltage source inverter (VSI) and current source inverter (CSI).
A VSI is one in which the dc input voltage would have to keep constant and independent of the load current drawn. The inverter dictates the load voltage while the drawn current shape is specifies by the load. These topologies are widely used because they behave as voltage sources naturally as required in many industrial applications, such as adjustable speed drives (ASDs), which are the most famous application of inverters. Similarly, these structures can be used as CSIs, where the independently controlled ac output is a current waveform. These structures are widely used in medium-voltage applications, where good-quality voltage waveforms are required. Static power converters, mainly inverters, are constructed from power switches and the ac output waveforms are therefore constructed of discrete values. This leads to the formation of waveforms that features fast transition rather than smooth ones.
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A dc voltage source which is supported by a large capacitor feeds the main converter circuit, a three-phase bridge. This dc voltage source can be a battery, fuel-cell stack, diode rectifier, or capacitor. Six switches have been used in the main circuit; each switch consists of a power transistor and an anti-parallel diode to provide bidirectional current flow and unidirectional voltage blocking capability. The V-source converter is commonly used. However it has following limitations
Muller, S., Prowse, D. L., & Soper, M. E. (2012, September 25). CompTIA A+ Cert Guide: Power Supplies and System Cooling | Foundation Topics | Pearson IT Certification. Retrieved March 20, 2014, from http://www.pearsonitcertification.com/articles/article.aspx?p=1945640
For any electric circuit, which consists of various passive elements (i.e. resistors, capacitors and inductors) the behaviour of the whole circuit to an applied ac voltage, is dependent upon both the behaviour of individual elements, and also on their arrangement in the circuit with respect to each other. If a dc direct voltage is applied to the elements that comprise the equivalent circuit, the resulting current can be measured using Ohms law.
· B-phase transformer (EMTU-TT01) · Feedback electronic wattmeter · Multi-range moving-iron ammeter · Instrument voltage transformer THEORY AND INTRODUCTION ----------------------- Transformers are used all over the world to step-up and step-down electricity. The transformer is one of the most commonly used electrical devices. The reason the transformer is so popular is because they range in size from 240V to well over 240kV, stepping -up and stepping-down electricity all over the world.
For the past few weeks, my classmates and I have been collecting data on the amount energy in kilowatts produced by solar panels on a given day. We have been guessing how many kilowatts of energy would be generated based on the forecast for each day, and then we were left with our estimates and the actual production of that day. In order to make this activity useful, we then took both numbers and found our percent error both weekly and daily. My best percent error days throughout the whole time were 1.09 and 0.44%. Now, needless to say, there were some bad days too. It was only easy to get a good percent error when the weather did what is was supposed to do, when we had an accurate scale to follow, and when there wasn’t
The year is 2200. The world is going through a fossil fuel shortage. Oil reserves are almost completely consumed and it is becoming impossible to find new fossil fuel sources. Not prepared for this event to occur, The United States, has no alternative options. As a result of the oil shortage, the standard of living deteriorates. Heat in homes, supermarkets full of food, and transportation, all basic necessities taken for granted, will be depleted because fossil fuels are used to power almost everything. The key to the prevention of this future is renewable energy. Unfortunately the support for the use of renewable energy is weak and ineffective. Unless the US puts forth effort to research and promote the use of renewable energy to consumers, conversion from fossil fuels to renewable energy will no longer be an option.
...ifficult. Consequently, if logic blocks are statically determined to be operating at low or high VDD, the placement and routing algorithms need to be modified accordingly as in [11]. However, static assignment of VDD to the blocks may prevent the ability to reduce power consumption or to meet timing constraints for some designs. In contrast, the use of VDD-programmability for each block helps to tune the number of high and low VDD blocks as desired by the application. In this approach, the challenge is in determining the VDD assignments to each block. The need for level converters wherever an low-VDD logic block drives an high-VDD block and the associated delay and energy overheads are an important consideration when performing these VDD assignments. Furthermore, positioning of the level converters influences the ability to assign lower VDD’s to the routing blocks.
Energy is the basic necessity of daily life. Nowadays, dependence on fossil fuels for energy needs becoming lower in numerous countries due to the potential of renewable energy to supply sustainable energy to the huge populations in many developing countries who are short of clean and continues energy. Generally, renewable energy can be defined as energy that is derived from natural resources which are constantly replenished and theoretically inexhaustible. Fossil fuels on the other hand can be described as energy that cannot be renewed and will eventually diminish. Thus, in many developing countries renewable energy is the alternative energy to replace non-renewable energy or commonly known as fossil fuels. In addition, according to Sorensen (2004), there is a greater demand for renewable energy sources nowadays due to the uncertainty of fuel price rise in living expenses. Commonly, there are many types of renewable energy available in our world such as wind power, biomass energy, solar energy, hydroelectric power and geothermal energy. However, the main three example of renewable energy are hydroelectric power, solar and biomass energy (Refer to Figure 1 in Appendix 1).
Basic Mathematics for Electronics seventh edition: Nelson M. Cooke, Herbert F.R Adams, Peter B. Dell, T. Adair Moore; Copyright 1960
There are generally two types of single-phase double-wound transformer constructions, the core type and the shell type. Core has a small cross section of iron; more number of turns is mandatory because the high flux may not reach the core. Core type is used for high-voltage service, since it has adequate room for insulation. Shell-type transformer has double magnetic circuit and three branches. Both windings are placed on the central branch. The coils reside in the entire space of windows.
...utput offset current and voltage and also, the value of voltage and current gain of this CCII is comparable with the CCII reported in [3].
The dc power input to the inverter is obtained from an existing power supply network or from a rotating alternator through a rectifier or a battery, fuel cell, photovoltaic array or magneto hydrodynamic generator. The filter capacitor across the input terminals of the inverter provides a constant dc link voltage. The inverter therefore is an adjustable-frequency voltage source. The configuration of ac to dc converter and dc to ac inverter is called a dc-link converter. Inverters can be broadly classified into two types, voltage source and current source
The proposed inverter configuration consists of boost converter, Dc bus, three phase inverter, 12 terminal transformer, LC filter and three phase load. The figure 1shows PV inverter topology and one set of five inverter depicted in figure 2.
(Pavelka and Čeřovský, 2002). Rectifiers convert an input AC voltage and current to an output DC voltage and current, choppers convert an input DC voltage and current to an output DC voltage and current of different values, inverters convert an input DC voltage and current to an output AC voltage, current, frequency and count of phases, AC converters convert an input voltage, current, count of phases and frequency to an AC energy with different parameters. The frequency converters that convert an input frequency to an output frequency and that simultaneously maintain the count of phases create a subgroup of AC converters
All useful generators of electricity come in two basic forms, alternating current and direct current. Direct current (dc) comes from generators that do not change in polarity, always producing a positive charge. In alternating current (ac) the polarity of the terminals is always changing from positive to negative. Thus you are left with alternating current flow. There are different ways of measuring and generating alternating and direct current.
With the depletion of fossil fuel resources comes speculations and debates about alternative energy sources. The world, including the Philippines, is practically dependent on a dwindling non-renewable source of energy. Today, experts are debating about and considering three options: Nuclear, Solar, or Wind Energy. Everyone has been accustomed to the bad image of nuclear energy as a result of the Chernobyl and Fukushima incidents above all others. The popular belief is that radiation from a nuclear meltdown is very harmful to humans and other living things—which is true—and that nuclear power plants are very dangerous and not ideal—which is not. According to Smith, et. al (n.d), all the nuclear disasters that ever occurred were caused by human error and natural disasters like tsunamis, not one because of system failure. Putting the false beliefs aside, with proper engineering and adequate maintenance by experts, a nuclear power plant is a very ideal and viable source of energy for the following reasons: