In a location with enough average wind speed and a suitable area for wind turbines, wind pumped storage system is a good combination with a hydro power plant. If it seems profitable to use wind turbines to produce power for pumps to pump water to an upper reservoir, and to make it reusable for hydro power plants, the next step would be to design such a system and implement it. In the case of grid connected systems using renewable energy , the total active power can be fed to the
The function of the electromagnet is to switch the polarity of the magnets as the current flows, keeping the motor running. The permanent magnet DC motor is used in applications that are high in power. The working principle of Permanent Magnet DC motor Brush DC motor and Brushless DC motor A brushed DC motor is an internally commutated electric motor designed to be run from a direct current power
A dc servo motor which is usually a dc motor of low power rating is used as an actuator to drive a load. A dc servo motor has a high ratio of starting torque to inertia and hence they make a faster dynamic response. The speed torque characteristic of this motor is flat over a broad range, as the armature reaction is negligible.
Abstract This report explains the basic concepts of linear power supplies and switching mode power supplies (SMPS). The main difference between the two supplies is the way they operate. A switched mode power supply provides a changeable voltage. It works by constantly switching the source on and off; the rate of which is dictated by the required voltage at the output while the power provided by linear power supplies provide a constant voltage at all times. The complexity of a switched mode power supply make it so hard to use as it requires an inductors whereas a linear power supply is often used because of it is simplicity.
The output stage of the converter and the stator winding of the motor must have the same number of phases but provided this simple requirement is met, any number of phases may be used. Three is still the common choice, however, not only for the reasons given above but also because the mass production of three-phase motors for the main excitation keeps their unit cost low and standardization enables motors to be sourced from any manufacturer. Despite the above, there has been an upsurge of interest in multiphase machines that is machines with more than three phases. There are several reasons for this, the principal ones
Generally a high voltage battery used for powering the hybrid electric vehicle (HEV) has high density such that it can store energy in a way to drive electric traction system. Power factor correction helps in improving the input current quality and the dc voltage regulation. DC-DC converter is helpful in charging the high voltage pack. It also isolates the utility mains from the traction battery pack. The charge of the resonant capacitor must be satisfied.
Abstract - Numerous industrial applications requires apparatus with require higher power and also some medium voltage motor drives and utility applications need medium voltage and megawatt power levels. It is vexatious to connect only one power semiconductor switch directly for a medium voltage grid. Respectively, a multilevel power converter structure has been introduced for high power and medium voltage situation as an alternative. Multilevel Inverters usually achieve high power ratings, and also enable the use of renewable energy sources such as photovoltaic, wind, and fuel cells. Multilevel Inverter's achieves higher power by using power semiconductor switches with several dc voltage sources.
This conversion takes place by the process of electrochemical combination of hydrogen with the oxygen from air. There are numerous advantages of fuel cells. One primary advantage is that it is a clean process unlike most of the combustion process as there is low emission of gases like NOx and CO2 and this attributed to not being an electrochemical process and not being limited by Carnot Cycle. Fuel Cells also offer higher efficiencies of electricity production. Other merits of this technology include flexibility and modularity, as it is not trouble significantly by issues of lubrication, wear, leakage and loss of heat that influence the working of conventional heat
For a fixed speed wind turbine, where ω is constant, which corresponds to a particular wind speed. For all other wind speeds the efficiency of the turbine is reduced . The aim of variable speed wind turbines is to always run at optimal efficiency, keeping constant value of tip speed ratio ‘λ’ that corresponds to the maximum Cp, by adapting the blades velocity to the wind speed changes. Hence, variable speed wind turbines are designed to operate at optimum energy efficiency, regardless of the wind speed . The conversion efficiency of variable speed wind turbine generator is maximum due to variable speed operation.
TRANSFORMER SIZING 6.1. Introduction: Transformers are widely used in power systems and it is considered as the most essential component of every power system. A transformer is a static device that works on Faraday’s law of electromagnetic induction and it is used to transfer electrical energy from one circuit to another or in other words it is a device which is used for decreasing or increasing the voltage of an alternating current. Basically there are two types of transformer i.e. step up and step down transformer but in general transformers are classified in different ways, depending upon their use, purpose, construction etc.