HVDC power transmission line can be constructed in many configurations like monopolar, bi-polar, tri-polar, back to back and many more. Their advantages and disadvantages has been discussed in [28] among them multi-terminal, multi-infeed or mesh type configuration is the better choice for aplications because of higher flexibility and efficiency. In a AC power grid several DC lines can be connected with existing AC line in this configuration with additional converters & inverters connected with grid as shown in Fig. 7. Fig.7 Mesh type combine AC-DC network In a multi-terminal high voltage grid, some HVAC & HVDC network is connected though converter and inverter respectively. Parallel or simultaneous AC-DC long distance power transmission is possible by using this configuration. The system operator can automatically select the optimal set of ac/dc transmission lines parameter for satisfying TEP criteria i.e. supplying load forecasts, minimizing investment costs, and optimizing market operations that becomes suitable for practical application.
VII. MODELING OF A 12 PULSE CONVERTER Fig.8 shows the configuration of a 12-pulse unidirectional power converter. It can be operated with or without filter
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In [34] authors has designed a new types of transformer less three-phase three-level NPC based power converter which performance has been analyzed in 2.64–4.16 kV DC, 5.1–12.8 kW. It’s performance like DC link voltage, efficiency & THD profile was acceptable. The authors assumed that this converter will be suitable for 15kV grid voltage. Converter switching circuit has been designed in SiC (Silicon Carbide) IGBT & Diodes as shown in Fig.18. So, this converter can be re-designed for medium or high voltage with SiC
The impact of the proposed sequences has been simulated for 0.4 modulation index with a 0.5 lagging power factor load (power factor angle 60°). The simulation setup consists of the following software: 1) MATLAB/Simulink – used to implement the modulation strategies and switching sequences, and 2) PSIM – used to simulate the T-NPC inverter running with an R-L load and to provide conduction and switching losses of each switch. The inverter switching pulses were generated within Simulink and were fed to PSIM through sim-coupler module which provides a link between PSIM and simulink for the purpose of co-simulation [29].
Fast charging is becoming the leading technology used to reenergize electric vehicles in 30 – 60 minutes. With the ownership of EVs doubling each year, the need to implement efficient, fast charging infrastructure is progressively increasing. There are two technical approaches to establish fast charging 1. via a high power, 3-phase AC connection from an AC charging post at the charging station to an on-board high power charger in the EV or 2. via a high power DC connection from a high power DC charger at the charging station directly to the terminals of the battery in the EV. In this section, we will review AC level 2, DC/AC level 3 charging stations to improve our knowledge and the design of our project.
Space Vector PWM (SVPWM) refers to a special switching sequence of the upper three power transistors of a three-phase power inverter. It has been shown to generate less harmonic distortion in the output voltages and or currents applied to the phases of an AC motor and to provide more efficient use of supply voltage compared with sinusoidal modulation technique. The biggest difference from other PWM methods is that the SVPWM uses a vector as a reference. This gives the advantage of a better overview of the system.
Abstract— this paper presents a brief overview of standards for power electronics. All the standards presented in this paper are currently active and are approved by the Institute of Electrical and Electronics Engineer Standards Association (IEEE-SA) and American National Standards Institute (ANSI).
Power electronic converters, especially DC/AC inverters have been extending their range of use in industrial application because they provide better system efficiency, reduced energy consumption and improved quality of power. The output voltage of inverter could be fixed or variable at a fixed or variable frequency and output waveforms are therefore made up of discrete values, producing fast transition rather than smooth ones [2]. The ability to
relationships.This new seven-level inverter is configured using a capacitor selection circuit and a full-bridge power converter, connected in cascade. The capacitor selection circuit converts the two output voltage sources of dc–dc power converter into a three-level dc voltage, and the full-bridge power converter further converts this three-level dc voltage into a seven-level ac voltage. In this way, the proposed solar power generation system generates a sinusoidal output current that is in phase with the utility voltage and is fed into the utility. The salient features of the proposed seven-level inverter are that only six power electronic switches are used, and only one power electronic switch is switched at high frequency at any time. A prototype is developed and tested to verify the performance of this proposed solar power generation system.
AC electrical energy in grid interactive PV system. To achieve direct medium-voltage which is present at grid without using bulky medium-voltage transformer ,cascaded multilevel converters are attracting more and
This report aims to discuss the working of DC-AC converter for photovoltaic systems and how it has been implemented to convert renewable energy into usable power to be supplied to the load (power supply application).A topology of a two-stage DC-AC converter has been designed in which a boost converter and a full bridge inverter act as an interface between the photovoltaic (PV) array and the power supply applications. A controlled strategy called Maximum Power Point Tracking (MPPT) technique has been used for achieving maximum power output at the load. Various modes of operation of the converter and the inverter are also discussed. MATLAB Simulink environment has been used for designing the circuitry and to observe various waveforms related to the output.
Power electronic converters, especially DC/AC inverters have been extending their range of use in industrial application because they provide better system efficiency, reduced energy consumption and improved quality of power. The output voltage of inverter could be fixed or variable at a fixed or variable frequency and output waveforms are therefore made up of discrete values, producing fast transition
I. INTRODUCTION: The power system is an interconnection of generating units to load centres through high voltage electric transmission lines and in general is mechanically controlled. It can be divided into three subsystems: generation, transmission and distribution subsystems. In order to provide cheaper electricity the
In this paper a zero voltage switched active network (Fig. 1) used in combination with three-phase ac to dc diode rectifiers is presented. It is shown that by using proposed switching network in three-phase ac to dc boost converter, zero switching losses are obtained while maintaining a unity input power factor. Active network capacitor, Cs, diodes D7, and D8, maintain a zero voltage during turn-off of Q1, and Q2, Capacitor, Cs, discharges through the boost inductors of the circuit thus limiting the rate of rise of current during turn-on. Moreover, the advantage of the proposed active network is that it can maintain a zero voltage switching over the entire range of the duty cycle of the operation. Consequently, boost stage can be used directly to control the dc bus voltage by varying the duty cycle at Constant switching frequency. The resulting advantages include higher switching frequencies, and better efficiency. Finally the operation of the active switching network is verified experimentally on a prototype three-phase ac to dc converter.
In the present era of advanced technologies, power electronics devices have wide applications. These devices are important for industrial and domestic uses but they generate the power quality problems [1-2].these problems are created on account of these devices
Mokhtar Ali et al. [41] gave new technique which allows the use of lower voltage Rated Semiconductor .This improves the performance of the system. This technique use SEPIC as the practical driver. L.K. Wong et al. [42] gave that Conventional method like averaging and small signal linearization are enough and powerful for basic converts like buck and boost but for high order like SEPIC these are not sufficient so the Meson’s gain formula and signal flow graph help the manipulation. Mohammad Mahdavi et al. [43] introduced a new PFC converter that have reduced no of component that subsequently reduces conduction losses. This proposed converter is operating in discontinuous conduction mode and having only voltage control loop i.e. no current loop is required whereas conventional arrangement have Booth loop controls and also operates in continuous conduction Mode. M.S. Song et al. [44] gave that by providing a direct new way between input and output by using some Auxiliary diodes and switches in addition to the SEPIC converter provided a highly efficient step up and step down converter in continuous mode. Ashish Shrivastava et al. [45] gave PFC based LED driver for power factor correction in the ac system. This topology consists PFC SEPIC converter which is operating to drive LED lamp in the continuous conduction mode. In this
IN RENEWABLE dc-supply systems, batteries area unit usually required to back-up power for electronic equipment. Their voltage levels are generally abundant under the dc-bus voltage. Bidirectional converters for charging/discharging the batteries area unit thus needed. For high-powered applications, bridge-type bidirectional converters have become a very important analysis topic over the past decade. For raising power level, a dual full-bridge configuration is sometimes adopted
This project has been carried out at the department of the electrical engineering at S.V.I.T. Vasad. It has been great opportunity to work with this project and get knowledge about this area of the power electronics.