Harmonic Elimination Research Papers - Academia.edu (original) (raw)

This paper presents a general three-phase model for wye/delta-extended transformers for time-domain analysis. Among other features, the modeling includes the nonlinearities of the core and the transformer phase-shifting can be of any... more

This paper presents a general three-phase model for wye/delta-extended transformers for time-domain analysis. Among other features, the modeling includes the nonlinearities of the core and the transformer phase-shifting can be of any value. The model is implemented in the SABER simulator and tested in a 24-pulse converter. The corresponding results are presented and special attention is given to harmonic elimination and inrush currents

Three-level NPC active-front-end three-phase (3LAFE) converters can be applied to high-power medium voltage applications, with 4-quadrant unity-power-factor operation, allowing a broad range for power conversion systems, such as... more

Three-level NPC active-front-end three-phase (3LAFE) converters can be applied to high-power medium voltage applications, with 4-quadrant unity-power-factor operation, allowing a broad range for power conversion systems, such as decentralized energy distribution and utilization. Switching losses and network interaction limit the operation of 3LAFE high-power converters, especially when GTO-converters are used.

This paper presents a specially designed power switching generator device that produces 4 types of waveforms; square-wave, sinusoidal PWM, quasi-sinewave or multilevel and high-frequency DC pulses with a total of 14 different distinctive... more

This paper presents a specially designed power switching generator device that produces 4 types of waveforms; square-wave, sinusoidal PWM, quasi-sinewave or multilevel and high-frequency DC pulses with a total of 14 different distinctive characteristics. The generator is exceptionally a useful tool to the students and researchers that dedicate themselves primarily in power electronics areas. The device is capable of generating the selected waveforms which can deliver a maximum 30W of power into a particular load. It is highly useful in harmonics analysis of inverters, true RMS measurements, switching devices driving signals, high-frequency switching transformer designs and filtering components for selective harmonics elimination.

This paper presents the application of high-power three-level active-front-end rectifiers to regenerate energy in a downhill conveyor system. The selective harmonic elimination method is used to eliminate harmonics 11 and 13, working with... more

This paper presents the application of high-power three-level active-front-end rectifiers to regenerate energy in a downhill conveyor system. The selective harmonic elimination method is used to eliminate harmonics 11 and 13, working with very low switching frequency, where six-pulse harmonic orders 6k±1 are eliminated by the delta-wye connection of the transformer. In this way, the input current at the mains is highly sinusoidal with small harmonics starting at frequencies of order 23 and 25. Resonances have been ...

Unified Power Quality Conditioner (UPQC) for harmonic elimination and simultaneous compensation of voltage and current, which improves the power quali ty offered for other harmonic sensitive loads. UPQC consist of combined series active... more

Unified Power Quality Conditioner (UPQC) for harmonic elimination and simultaneous compensation of voltage and current, which improves the power quali ty offered for other harmonic sensitive loads. UPQC consist of combined series active power filter that compensates voltage harmonics of the power supply, and shunt active power filter tha t compensates harmonic currents of a non-linear load. In this paper a new control algorithm for the UPQC system is optimized and simplified without transformer voltag e, load and filter current measurement, so that system performa nce is improved. The proposed control technique has been evaluated and tested under dynamical and steady state load co nditions using PSIM software. The laboratory prototype experimental results for shunt active filter part are given.

The problem of eliminating harmonics in a switching converter is considered. That is, given a desired fundamental output voltage, the problem is to find the switching times (angles) that produce the fundamental while not generating... more

The problem of eliminating harmonics in a switching converter is considered. That is, given a desired fundamental output voltage, the problem is to find the switching times (angles) that produce the fundamental while not generating specifically chosen harmonics. In contrast to the well known work of Patel and Hoft (1973, 1974) and others, here all possible solutions to the problem are found. This is done by first converting the transcendental equations that specify the harmonic elimination problem into an equivalent set of polynomial equations. Then, using the mathematical theory of resultants, all solutions to this equivalent problem can be found. In particular, it is shown that there are new solutions that have not been previously reported in the literature. The complete solutions for both unipolar and bipolar switching patterns to eliminate the 5th and 7th harmonics are given. Finally, the unipolar case is again considered where the 5th 7th, 11th, and 13th harmonics are eliminated along with corroborative experimental results.

Multilevel inverters are emerging as the new breed of power converter options for high power applications. They typically synthesis the staircase voltage waveform (from several dc sources) which reduced harmonic content. This paper... more

Multilevel inverters are emerging as the new breed of power converter options for high power applications. They typically synthesis the staircase voltage waveform (from several dc sources) which reduced harmonic content. This paper presents a simple selective harmonic elimination (SHE) modulation for single-phase cascaded H-bridge (CHB) multilevel inverter. The optimum switching angle of the transcendental equations describing the fundamental and harmonic components is solved by means of the Newton-Raphson (NR) method. The proposed SHE scheme is performed through simulation using MATLAB/Simulink. This simulation results are then verified through experiment using Altera DE0-Nano field-programmable gate array (FPGA). The proposed SHE is efficient in eliminating the lowestorder harmonics and producing a higher quality output waveform with a better harmonic profile.

Programmed PWM technique requires solution of set of non-linear transcendental equations in order to obtain the switching angles as well as for controlling the fundamental component of inverter output voltage. This paper presents a new... more

Programmed PWM technique requires solution of set of non-linear transcendental equations in order to obtain the switching angles as well as for controlling the fundamental component of inverter output voltage. This paper presents a new method to determine the optimum switching angles for Selective Harmonic Eliminated PWM (SHEPWM) inverter. The complete solutions for unipolar SHEPWM switching pattern which produce the fundamental while not generating specifically chosen harmonics are investigated. The estimated angles are applied to an inverter circuit in order to verify its validity through output waveforms, THD and FFT. Since the THD is high due to low number of harmonic orders are eliminated, a low pass filter is also designed in order to filter the unwanted harmonics.

A comparison of sinusoidal pulse width modulation (SPWM) and selective harmonic elimination (SHE) in a multicell DC/AC converter is presented. The genetic algorithm finds the existence optimal solution set of switching angles for each... more

A comparison of sinusoidal pulse width modulation (SPWM) and selective harmonic elimination (SHE) in a multicell DC/AC converter is presented. The genetic algorithm finds the existence optimal solution set of switching angles for each required harmonic profile. The dc links of each full bridge cell are supplied by individual high frequency DC-DC isolation stages which are connected in parallel considering the dc input of the total system. Furthermore, the cells which are operated in an interleaved SPWM mode or SHE mode ...

In this paper, a new topology based on a direct ac/ac converter is proposed for a single-phase dynamic voltage restorer (DVR). This topology uses the minimum switches (i.e. two switches) and does not require dc-link energy storage... more

In this paper, a new topology based on a direct ac/ac converter is proposed for a single-phase dynamic voltage restorer (DVR). This topology uses the minimum switches (i.e. two switches) and does not require dc-link energy storage elements. As a result of elimination of the energy storage elements, the cost and the physical size of the proposed topology is reduced. A new control method is also proposed for direct ac/ac converter in the proposed topology. The proposed topology is properly able to compensate voltage sag and swell in the desired range according to the turn ratio of the injection transformer and is also able to eliminate harmonics and flickers. Considering these capabilities, the proposed topology is a several purpose device with a simple topology. It is worth noting that all of these capabilities are not integrated in the conventional DVR topologies. It is obvious that the proposed topology would not face any problems in long time compensation due to the fact that it provides the required energy directly through the grid. The proposed topology can be easily extended to n-phase systems such as three-phase based on the same principle of the operation. In n-phase systems, the voltage sags and swells can be properly compensated regardless of the balanced or unbalanced operation. The experimental and simulation results are presented to validate the capabilities of the proposed topology.► A new and improved topology for dynamic voltage restorer (DVR) is proposed. ► The proposed topology is based on ac/ac converter. ► The proposed topology does not require energy storage elements. ► Using the proposed topology, the cost and size of the DVR is reduced. ► The proposed DVR uses minimum number of switching devices.

Selective harmonic elimination (SHE) is an efficient method to eliminate low-order selected harmonics. However, due to nonlinearity in the problems, many optimization techniques give unsatisfied performances in finding optimum switching... more

Selective harmonic elimination (SHE) is an efficient method to eliminate low-order selected harmonics. However, due to nonlinearity in the problems, many optimization techniques give unsatisfied performances in finding optimum switching angles for the SHE. This paper proposes a modified moth-flame optimization algorithm to eliminate selective harmonics in cascaded multilevel inverters. The optimization algorithm is employed to find sets of optimum switching angles for cascaded 5-level, 7-level, and 9-level inverters. The results have shown that modified moth-flame optimization is beneficial in finding optimum switching angles. It performs better than moth-flame optimization (MFO) and differential evolution (DE) algorithms. The optimum switching angles are applied to generate switching pulses for a cascaded 9-level inverter to demonstrate the algorithm’s accuracy. As a result, the low-order harmonics are entirely removed from the ac output voltage of the inverter.

The Selective Harmonic Elimination Pulse-Width Modulation (SHE-PWM) is an effective method for harmonic elimination in multilevel inverter. This paper presents the solutions of Selective Harmonic Elimination (SHE) problem based on Genetic... more

The Selective Harmonic Elimination Pulse-Width Modulation (SHE-PWM) is an effective method for harmonic elimination in multilevel inverter. This paper presents the solutions of Selective Harmonic Elimination (SHE) problem based on Genetic algorithm (GA) and Particle Swarm Optimization (PSO) techniques. Total Harmonic Distortion (THD) of output voltage is minimized maintaining selected harmonics within allowable limits. A comparison has been drawn between GA and PSO techniques related to optimization.

The main drawback of the diode neutral-point-clamped (NPC) converter is the unequal loss distribution among the semiconductor devices which confines the maximum output power and the switching frequency. To address this drawback, switching... more

The main drawback of the diode neutral-point-clamped (NPC) converter is the unequal loss distribution among the semiconductor devices which confines the maximum output power and the switching frequency. To address this drawback, switching state redundancy is required to evenly distribute the losses and can be achieved differently as the level of the converter changes. For instance, the three-level active NPC (3L-ANPC) converter has switching state redundancy and is derived from the 3L-NPC converter by adding an anti-parallel switch to the clamping diodes; in the 4L-ANPC converter, the combination of a 2L converter and a 3L-ANPC converter is used; in a 5L-ANPC converter, the combination of the 3L-ANPC and 3L-flying capacitor (FC) converter is advantageous. The paper discusses selective-harmonic-elimination (SHE) pulse-width-modulation (PWM) strategies for the above mentioned converters and explains how loss distribution can be achieved.

In electric railways, thyristor rectifiers are used in order to control the speed. As a consequence in addition to substantial input lead current, an enormous amount of harmonics is injected into the grid. To avoid such harmonics as well... more

In electric railways, thyristor rectifiers are used in order to control the speed. As a consequence in addition to substantial input lead current, an enormous amount of harmonics is injected into the grid. To avoid such harmonics as well as reactive power compensation, reactive power hybrid filters consisting of active and passive filters are utilized. Hybrid filters have several different structures. Since electric railway has a non-linear and variable nature, a novel hybrid filter structure is designed that compensates reactive power and eliminates harmonics to attain desired harmonic level regarding the conventional allowable harmonics level standards. The designed filter model is simulated in MATLAB/SIMULINK and then applied to a harmonic model of an electric railway.