Abstract—This paper describes design considerations and performance analysis of a novel on-line single-phase to three-phase uninterruptible power supply (UPS) with reduced number of switches. The proposed topology uses only 5 active switches reducing the cost of the system compared to the traditional 10-switch topologies. The proposed UPS consists of a single-phase rectifier/charger, a two-leg/three-phase inverter connected to load, battery bank, DC link capacitor and an AC inductor. Detailed circuit operation and analysis as well as simulation results are also presented to verify its feasibility.
Keywords-Uninterruptible Power Supply (UPS); Single-Phase to Three-Phase Conversion; Reduced Switches
I. INTRODUCTION
Introduction should give a general background and review of the paper or work done by other engineers in the field. It should also contain literature review, objective and scope of the paper. Leave one space between two paragraphs (Do not indent paragraphs). Uninterruptible Power Supplies (UPS’s) are nowadays indispensable equipment in supplying power to critical and sensitive loads. They protect sensitive loads against many existing disturbances in utility network like voltage variations, transients and harmonics. Applications of UPS systems include medical facilities, life supporting systems, data centers, emergency equipment, telecommunications and industrial processing systems.
Ideally, a UPS should deliver clean and uninterrupted power to the load, and at the same time draw sinusoidal, near unity power factor current from input supply. Additionally, static UPS’s must be able to switch between utility and storage batteries as alternate energy sources. This switching must take place in zero or minimum tim...
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Besides the calculation of electrical characteristics of the power system, power flow analysis can also help to optimize the system operating conditions and minimize the power losses [19].
This paper introduces the use of the voltage multiplier technique and passive absorption circuit applied to the non-isolated dc-dc converter in order to obtain high efficiency and high voltage gain. A passive absorption circuit is inserted in the interleaved flyback converter to transfer the leakage energy to load. The operation principle of the circuit is explained. This paper also deals with MPPT controlled high step up dc-dc converter. The switching element used in the flyback converter is MOSFETs, which is completely on and completely off. This is because MOSFET has high power rating and high switching speed. Moreover, high voltage conversion ratio is achieved. The simulated results are presented with R load.
Over the past few decades, there has been an increasing use of induction generator particularly in wind power applications. In generator operation, a prime mover (turbine, engine) drives the rotor above the synchronous speed. Stator flux still induces currents in the rotor, but since the opposing rotor flux is now cutting the stator coils, active current is produced in stator coils, and motor now operates as a generator, and sends power back to the electrical grid. Based on the source of reactive power induction generators can be classified into two type namely stand-alone generator and grid-connected induction generator. In case of stand-alone IGs the magnetizing flux is established by a capacitor bank connected to the ma...
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
These inverters are meant to operate isolated from the electrical distribution network (off-grid) and require batteries for proper operation. The batteries provide a constant voltage source at the DC input of the inverter.
The above topology, each H bridge require separate Dc sources with equal rating and separate DC sources make it system bulky and costlier [4]. Cascade H bridge inverter employing single phase and three phase transformers with single DC input is also presented [5]. This configuration use single DC input and require additional three phase transformers. The main advantages of this paper is that, uses only one DC input, one three phase transformer and minimum number of power switches (15 switches). For the proper inverter operation, high quality the gating pulses to be generated to the inverter switches. For generating gating pulses, Space Vector Pulse Width Modulation (SVPWM) techniques have been used. This paper proposes comparative studies of three phase PV inverter using PI and fuzzy logic controller and switching losses are also
Storage of electrical energy is very important in many applications especially electrical appliances which require mobility or short burst of energy over a short duration of time. There had been many technologies developed to emulate characteristics of an ideal power supply which can store large amounts of energy, providing good power output as well as being able to be charged and discharged rapidly without deterioration of any type. A typical power storage device can be characterized by its power density and its energy density, noting that with our current technology, none which can achieve the best of both.
The capacitor banks are assembled from capacitor units connected in three-phase grounded-wye, ungrounded-wye, or delta configurations. The capacitor banks are either fixed or switched. Switched capacitors give added flexibility in the control of system voltage, power factor, and losses. Switched capacitors are usually applied with some type of automatic switched control. The control senses a particular condition. If the condition is within a pre-set level, the control's output level will initiate a close or trip signal to the switches that will either connect or disconnect the capacitor bank from the power
The induction motor takes a huge part of the industry, as they are introduced in everyday applications for example, toys, water pumps, fans, washing machines and cars. The reason that the three phase induction motors are very popular is due to the simplicity of the mechanisms included, low cost availability, low risk of failure, economical and can produce large torques. Other reason that the three phase induction motor is widely used is that it can be easily handled and easily fabricated to suit all kinds of applications, the three phase induction motors can be manipulated to produce high or low torques and high or low speeds.