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Conventional single phase inverter offers a square wave output which when applied to electrical appliances may damage the later reducing its efficiency and life as this inverter output waveform is not sinusoidal and contains lower and higher order harmonics in addition to fundamental. On the other hand Selective Harmonic Elimination with Pulse Width Modulation (SHE-PWM) offers a fine control of the...
This paper presents a new idea to solve the selective harmonic elimination (SHE) equations with non equal dc sources using Hybrid Newton Raphson Method (HNRM). This technique is a combination of genetic algorithm (GA) and Newton Raphson Method (NRM). The HNRM technique effectively eliminates the lower order harmonics from the output voltage of the converter. In this paper, it has been also shown that,...
This paper shows a method for optimization of CHB inverter's harmonic performance under Selective Harmonic Elimination Pulse Width Modulation (SHEPWM) control. The optimization techniques are used for solving the set of non-linear transcendental trigonometrical equations. SHE is implemented to reduce the THD value. The set of non-linear equation is minimized by Big Bang-Big Crunch optimization technique...
Electrical energy generation by using Photovoltaic system is becoming popular day by day. This paper presents a control topology for multilevel inverters used in standalone PV system. A hybrid technique is used to optimize the switching angles of thirteen levels single-phase cascaded multilevel inverter for selective harmonics elimination. The nonlinear transcendental equations problem is solved by...
We are considering the problem of controlling wind turbine synchronous generators driven through AC/DC rectifiers and DC/AC inverters. The control objectives are threefold: (i) forcing the turbine speed to track a reference signal, (ii) regulating the DC Link voltage, (iii) enforcing power factor correction (PFC) with respect to the power network. First, a nonlinear model of the whole controlled system...
The large demand of dynamic reactive power for MIDC recovery is a big challenge to voltage stability of the receiving system. Thus, the research on active power (P) and reactive power (Q) characteristics of inverter station in the recovery process of multi-infeed HVDC (MIDC) attracts more and more attention. With the CIGRE HVDC benchmark, this paper studies the P and Q responses under various faults...
When several high voltage direct current (HVDC) systems simultaneously recover after severe faults, absorbing large amounts of reactive power from the receiving AC systems, presents new challenges for the transient voltage stability of multi-infeed HVDC (MIDC) systems. Actually DC power recovery characteristics could be controllable to some extent by selecting voltage dependant current order limiter...
Output dc voltage from Fuel Cell (FC)/Photo Voltaics (PV) needs to be conditioned and converted into ac form before integrating to grid. Normally, two stage converters are used for this purpose. Two stage converters have several disadvantages like low efficiency, more number of components, big size, etc. especially when they are operated at low input voltages. In this paper, a coupled inductor based...
Due to the focus on clean and green environment, the interest on electrification of existing transportation system is increasing. In Hybrid Electric Vehicle (HEV), the "idle-stop" and hence fuel economy is achieved by using integrated starter generator (ISG). This paper discusses the comparative evaluation of active bidirectional converter based ISG and passive quasi-Z source inverter (qZSI)...
Harmonic elimination pulse width modulation (HEPWM) method has been widely applied to improve the harmonics profile of the multilevel voltage source inverter (MVSI). However, the computation of the HEPWM switching angles for MVSI is very challenging due to the non-linear and transcendental nature of the equations. With the proliferation of low cost and powerful computers, the soft computing (SC) approach...
Generally, selective harmonic elimination (SHE) complexity for multilevel inverters increases with the increase in number of levels. In this paper, a novel approach for SHE is introduced. This approach is based on cancelling the 5th and 7th order harmonics irrelevant of the number of levels in threephase multilevel converters, such that the solution for the angles required for the proposed SHE mimics...
This paper presents developed compact algorithms of space vector pulse width modulation (SVPWM) for six-switch and four-switch three-phase inverter. Calculations of the desired voltage vector in the PMSM drive are presented, an optimal voltage vector sequence and scaling factors for SVM has been derived to synthesize the reference voltage vector in each sampling period for healthy and fault drive...
The control systems typically use the conventional PID (Proportional, Integral, Derivative) controller to control the direct current (DC) voltage [1]. The obtained control results are relatively well when PID controller is applied, but the design parameters are not absolutely precise and sensitive to the changes of system parameters. The PID controller is used to control the frequency of three-phase...
This paper presents a unified power quality conditioner (UPQC) and its control strategy for assisting the fault ride-through operation of large-scale photovoltaic (PV) power station. The output voltage of PV station can be controlled to its rated value with UPQC under high grid voltage fault condition. Moreover, it can absorb reactive power from the grid under high voltage condition to support the...
Due to the presence of the low-order background voltage harmonics in the grid, it will cause higher current harmonics in the AC side of the grid inverter with Selective Harmonic Elimination PWM (SHEPWM). Therefore the grid inverter with traditional SHEPWM has not prevailed since it is unable to overcome the background harmonics of the utility and satisfy the power quality requirement. In this paper,...
As the distributed generators are connected together through inverter interface in the microgrid, the control of the control of the interface inverter has an important influence on the operating performance of microgrid. In the paper, the study focuses on the control of the interfaced inverter, when microgrid operates in the islanded mode. In order to make the microgrid property similar to the utility...
In recent years, there have been an increasing number of photovoltaic (PV) generators integrated into the modern distribution power network. However, the introduction of a large number of PV units could have a negative impact on the distributed PV grid-connected power generation systems, such as polluting the grid, and causing grid instability, even resulting in the voltage collapse if the relevant...
This paper presents a self-oscillating electronic ballast for a 36 W LED string. The design consists of a simple control that reduces the component number and cost of the ballast. Self-oscillating converters are popular in compact fluorescent lamps; therefore, it is proposed the use of this self-oscillating control technique for the LED lamp. The self-oscillating LED driver represents a very suitable...
Multilevel inverters are one of the most popular and useful type among all and have lots of usage like less disturbance and the possibility to function at higher switching frequencies than ordinary two-Level inverters. They can be used at different applications like electronic derivers, wind turbines and solar plants. In order to feed the DC current produced by PV panels to the inverters, power electronic...
Three-level neutral point clamped (NPC) inverter topologies are becoming more and more the interest of studies, especially in grid connected systems, due to their advantages compared to other multilevel inverters. Synchronization with an AC source remains a challenge ring current injection to the grid. In order to enhance the performance and the immunity of such grid connected inverters, a sliding...
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