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This Paper presents a framework to carry out a simulation for closed loop speed control of BLDC motor with PID and Modified PID controller. The novelty of this paper lies in the design of modified PID controller to track the reference trajectory with and without load in addition to minimizing the initial overshoot. The simulation includes all realistic values and components of the motor. The three phase inverter and its control algorithm is modeled and simulated using MATLAB Simulink. The PID and Modified PID controller track the reference speed with and without load disturbances in closed loop control but the demerit of conventional PID can be observed in its steep overshoot in the closed loop transient response. The speed, torque, dc-link current and back-emf waveforms are analyzed for various load torque conditions through MATLAB Simulink. [ABSTRACT FROM AUTHOR]

In this paper, a transformerless distribution static synchronous compensator (DSTATCOM) based on the cross-switched (CS) multilevel inverter (CSMLI) is introduced. In comparison with the well-known cascaded h-bridge (CHB) topology, CS inverter produces higher number of voltage levels using fewer number of power components. Since CS inverter produces ac side voltage with high quality and has the ability to work at high voltage and power levels, the proposed CS-DSTATCOM is directly connected to the distribution grid without the need for a transformer. In the proposed CS-DSTATCOM, all the dc sources are replaced with dc capacitors. In this paper, an effective voltage balancing control scheme is proposed to keep the capacitors voltages balanced in the CS structure. The control scheme balances the capacitors voltages in two levels, i.e., inter-cell and within-cell level. On the other hand, the over-voltage and under-voltage phenomena are of the most common power quality (PQ) issues in distribution grids. The proposed DSTATCOM is able to cope with these issues by exchanging reactive power with the grid. Applying the CSMLI in the DSTATCOM structure as well as the capacitors voltage balancing methods are the main novelties of the paper. Also, the capacitors values are considered to be different (which is unavoidable in practice) while their voltages are balanced using the proposed voltage balancing methods. In this paper, a CS-DSTATCOM has been designed for 11 kV distribution grid and several simulation results are provided in the MATLAB/Simulink environment which validate the feasibility and performance of the proposed CS-DSTATCOM. [ABSTRACT FROM AUTHOR]

Numerous techniques have been used in the literature to produce switching signals in multilevel inverters (MLIs). Reducing the number of switching component in multilevel inverters is another area of interest in the literature. In this paper, a MLI with low switching number has been designed and worked successfully in harmonic elimination method. For this purpose, a novel genetic algorithm based SHE-PWM in a single phase 11-level inverter is presented in order to eliminate the switching signals. Also, total harmonic distortion (THD) analysis, which depends on switching angles for multilevel inverters, in a wide modulation range of 11-level inverter topology is presented. Hence, the switching angles are first estimated by Genetic Algorithm (GA) method, in which a certain number of harmonic components are eliminated. THD analysis is performed using both analytical and MATLAB simulation using calculated switching angles. The proposed method is applied to an 11-level inverter to eliminate 3th, 5th, 7th and 9th harmonic content in the range of modulation index 1.5 and 4. A simulink model which provides simulating and validating the accuracy, dynamics and continuity of the GA solution, was created. Experimental validation is not carried out in this study. Considering the simulation results and similar studies in the literature, the success of the reduced inverter topology and GA supported harmonic elimination technique was observed. [ABSTRACT FROM AUTHOR]

In this paper, minimization of total harmonic distortion (THD) is discussed for the output voltage of multilevel inverter. THD minimization is an efficient method in reduction of the harmonic components of the inverter’s output voltage. In multilevel inverters, the switching angles can be selected in a way that the output voltage THD will be minimized. Given that THD minimization is an optimization problem, intelligent algorithm is found to be an appropriate alternative in this regard. Shuffled Frog Leaping Algorithm and Harmony Search Algorithm are employed to find optimum switching angles to generate desired voltage value in the possible minimum THD. The obtained results of two algorithms are compared with each other to determine that which algorithm is more efficient in this regard. Also, both simulation and experimental results indicate superiority of this approach over the published work using GA in this concept. The experiments are conducted on a seven-level inverter to validate the feasibility of presented approach. [ABSTRACT FROM AUTHOR]

Solar based renewable power generation is more important to compensate fossil fuel power generation. It is necessary to implement Maximum Power Point Tracking (MPPT) system to reduce cost of PV array system by decreasing the number of solar panel required to generate the power. Since the solar power fluctuates with the sunlight's intensity, it requires conversion to maintain the desired voltage like inverters. In this paper, a series compensation scheme is suggested. Perturbation and observation (P&O) algorithm of MPPT. A single stage architecture of photovoltaic generators which is used for residential applications are incapable to boost the voltage of the PV modules and also provides deficient input voltage range in spite of providing deplete power loss. This research work proposes a series connection of buck-boost converter which operates only in buck mode and also processes a fraction of the power input from the inverter while operating at high efficiency. This inverter focused SPWM pulses and produces pure sine wave as output. The duty ratio is decreased to less than 0.5 hence switching losses also reduced. The proposed logic is carried out in simulation and hardware setup of 480W prototype and the results were analyzed to enhance the advantage of the series compensation approach. [ABSTRACT FROM AUTHOR]

This paper describes the simulation model and the harmonics analysis of multi level inverters fed RL load and induction motor load. The SEIG fed H-bridge multi level inverter (MLI) for variable speed wind energy conversion systems are considered for various stand alone applications. In this paper, the SEIG fed cascaded five levels inverter for induction motor load systems are clearly explained with the help of MATLAB / SIMULINK models. The generated voltage of the wind driven self - excited induction generator (SEIG) is mainly depending on the wind velocity fluctuations, appropriate capacitance values and load conditions. The five levels cascaded inverter has interface with the wind driven self -- excited induction generator (SEIG). The variable magnitude, variable frequency voltage of the generator can be controlled by choosing the proper modulation index. The simulation and harmonic analysis of the proposed inverter will be discussed and the total harmonic distortion will be evaluated. [ABSTRACT FROM AUTHOR]

This paper presents three-level (NPC) shunt active power filter the performances based on fuzzy control techniques to compensate harmonic currents generated by non-linear loads operating under non ideal voltage conditions. Shunt APF is the best solution to eliminate harmonics drawn from nonlinear load especially for low power system, the most inverter used is the two-level voltage source inverter. Multilevel inverters are being investigated and recently used for APF topologies. Today Three-level inverter is one of the most used converters in the majority of industrial applications, such as machine drives and power active filters. The control strategy used is based on the synchronous reference frame detection method that gives a good performance particularly if the source voltage is unbalanced or distorted. The new control scheme proposed in this work is based on fuzzy techniques and it is designed to improve APF compensation capability by adjusting the current error based on fuzzy rule. To improve the output three-level voltage inverter and avoid an unbalanced AC voltage waveform a neutral-point potential voltage compensator based on proportional controller is used with a proportional integral controller required to maintain dc voltage constant. The results of simulation study obtained using Matlab-Simulink and SimPowerSystem Toolbox are found quite satisfactory to eliminate harmonics and reactive power components from utility current. [ABSTRACT FROM AUTHOR]

In this paper, a comparison on Total Harmonic Distortion (THD) by using different pulse width modulation schemes for an industrial drive application is performed. The induction motor drive system driven by a wind energy conversion system is modeled using a Self-Excited Induction Generator. To obtain a constant frequency output an Impedance Source Inverter (ZSI) is connected between the source and the load. The ZSI is selected to avoid the shoot-through limitation which is observed in other conventional PWM inverters. The PWM switching techniques like Trapezoidal PWM, Sinusoidal PWM and Space Vector PWM techniques are mathematically modeled operating at a switching frequency of 10 kHz to control the induction motor drive system though pulse generation. The proposed method is simulated using MATLAB program and the current harmonic levels for driving the IM drive are analyzed. The comparative analysis of current harmonics illustrates the efficient implementation of PWM technique for the drive applications. Based on the simulation evaluation a similar hardware prototype model is setup for a 900W system using Space Vector PWM technique and the results are compared. [ABSTRACT FROM AUTHOR]

This paper presents a shunt active power filter performances based on three-level (NPC) inverter using conventional pulse width modulation (PWM) and Ann's controllers to mitigate current harmonics generated by non-linear loads. Shunt APF is the best solution to eliminate harmonics drawn from nonlinear load especially for low power system, the conventional scheme based on the two level inverter controlled by hysteresis controller presents several drawbacks such us high inverse voltage applied to power components, degraded output voltage inverter waveforms, etc. Today three-level (NPC) inverter and intelligent controllers are widely used in different industrial applications. To take advantages of these inverter topology and artificial intelligent controller performance a novel control scheme based on Ann's current controller is proposed in this work. The control strategy adopted is the synchronous current detection method, it is easy to implement and permits a good extraction of reference currents compensation. The numerical simulation is performed using MATLAB-Simulink and SimPowerSystem Toolbox. The simulation results obtained in steady and transit states show the effectiveness and the superiority of Ann systems compared to PWM controller. [ABSTRACT FROM AUTHOR]

This paper presents an experimental study on repetitive partial discharge inception probability of twisted enameled wires subjected to modified inverter-surges. In order to obtain the probability curves as a function of the voltage amplitude, we develop an automatic measurement system of partial discharge inception probability for the twisted enameled wires subjected to the repetitive pulses with step-by-step increasing in the voltage height. Very fast oscillated pulses with or without polarity-reversal and an impulse-like pulse without oscillation are used as the modified inverter-surges. In the test for the impulse-like voltage, repetitive partial discharge inception voltage (RPDIV) decreases with increasing the pulse width. On the other hand, RPDIV for the polarity-reversed pulse with a higher oscillation cycle is lower than that for the pulse with lower oscillation cycle. The difference of PD inception probability between the voltage waveforms will be discussed on the basis of charge dynamics on the wire surfaces. [ABSTRACT FROM AUTHOR]

This paper discusses the difference between the three fundamental types of multilevel inverter (MLI) topologies, which are the neutral-point-clamped, the flying capacitors and the cascaded H-bridges. The sinusoidal pulse width modulation technique was used to simulate the output voltages and currents of the MLI inverters. The total harmonic distortion (THD) was estimated for each topology and each voltage level. Moreover, the simulation results indicate that the cascaded structure exhibited a lower THD value even when increasing the number of the output voltage. Furthermore, a new key parameter was defined as cost efficiency factor and used to compare the three topologies. Evaluation results of this factor indicate that the cascaded structure was the most advantages as it reduces stress effect on the inverter switches by eliminating the power diodes and capacitors. [ABSTRACT FROM AUTHOR]

This paper deals with the active power flow control in a transmission line thus improving Available Transmission Capability (ATC) using Static Synchronous Series Compensator (SSSC). For the analysis, a generator supplying two parallel transmission lines connected to a load as 2-bus system is considered. When the load increases, active power flow in the transmission lines is shared based on their limits depending on ATC which is based on power handling capacity according to the demand. Therefore, for effective control of the active power flow considering the power handling capacity, SSSC is connected in series with one of the transmission lines. SSSC controls the active power flow in transmission line by injecting voltage in quadrature to the line current. SSSC designed in this work is a Voltage Source Inverter (VSI) which provides pulses and would help to inject the required voltage in quadrature to the line current. The PWM pulses of the VSI based SSSC is generated by dsPIC microcontroller. SSSC is modeled under both MATLAB / Simulink environment and implemented on a scaled down model of 150 km, 15.6 mH transmission lines connected in between generator and load. [ABSTRACT FROM AUTHOR]

Due to their numerous advantages, multilevel inverters are commonly utilized in high and medium voltage applications. Design and simulation of Six-Switch Five-Level Active Neutral Point Clamped Inverter (6S-5L-ANPC) associated with LC filter is presented, the inverter can produce pure sinusoidal voltage, the proposed modulation can satisfy the regulation of the flying capacitor voltage, the behavior of 6S-5L-ANPC inverter is validated through simulation, limitation in the present design of the inverter is discussed. However, the converter is not able to maintain the FC voltage balancing under modulation index variation. To overcome this limitation, a PID Controller based in output voltage control is proposed. The aim of control is: i) create a sinusoidal voltage at the converter output with amplitude and frequency set by the reference signal, ii) guarantee the self-balancing of the FC capacitor under variable load and reference voltage variation. The controller is tested under various operating situations in simulation. The validity of this strategy is demonstrated using simulation results. [ABSTRACT FROM AUTHOR]

Minimization of Total Harmonic Distortion (MTHD) for the line-to-line output voltage of multilevel inverters has been studied in this work. Harmony Search (HS) Algorithm with artificial neural networks (ANN) has been employed to solve the aforementioned problem with considering constant and alterable DC sources in order to minimize Total Harmonic Distortion more efficiently. The nearest solutions provided by HSA obtain a smooth data set that is desired for the neural network training. MTHD is suitable for some cases, e.g. multilevel electrical drives and flexible AC transmission system devices such as multilevel static VAR compensator, multilevel unified power quality conditioner and multilevel unified power flow controller, where DC link voltages are altering. MTHD not only optimizes the switching angles, also finds the optimum values for DC links. In this work THD minimization with employing both constant and alterable DC sources has been researched and compared with each other. Also a comparison is made with a recently published paper using GA, which validates that the proposed scheme is more efficient in this regard. Numerical results for a test case, seven-level inverter, reveal that the presented method is feasible. [ABSTRACT FROM AUTHOR]

In this paper, we propose design of the boost converter with hybrid transformer ratio for hybrid power source charging station. This converter is addressed as DC step up converter. This converter has high ratio conversion that converter to DC bus 24 Volt to AC system 220Volt. The combination between resonance modes and pulse width modulation (PWM) is used to achieve high voltage ratio conversion. The advantage of proposed method is use only single switching device; therefore it is easy to control. Moreover, voltage stress on diode and switching device is relatively low and independent from input voltage. The experiment result show that the converter is able to operates in wide range input voltage and has good conversion efficiency up to 90%. Based on the operation and conversion characteristic, the converter can be operated in power inverter with duty ratio 0.7-0.8 to synchronizing with AC system. [ABSTRACT FROM AUTHOR]

The influence of injecting third harmonic signal into three-phase sinusoidal reference signal of natural sampled PWM technique on output current ripple and neutral current of three-level inverter is analyzed in this paper. Expressions for both inverter output current ripple and neutral current as a function of PWM reference signal are derived first. Then, it is shown that injecting one fourth or twenty five percent third harmonic signal into three-phase sinusoidal reference signal may produce minimum output current ripple and neutral current. The twenty five percent third harmonic injection signal can simultaneously minimize output current ripple and neutral current of the three-level inverter only for unity power factor operation. Simulation and experimental results are included to show validity of the analysis results. [ABSTRACT FROM AUTHOR]

The article presents a comparative study of the Carrier Overlapping Pulse Width Modulation (COPWM) techniques for the Diode clamped Multi Level Inverter (DCMLI). It explores the capability of the Control Freedom Degree (CFD) to support the effectiveness of Pulse Width Modulation (PWM) strategies through simulation and experimentation. It highlights the lower percentage of total harmonic distortion (THD) and less number of dominant harmonics of the COPWMA-A strategy compared to other strategies.

The article discusses the use of lagrangian relaxation- particle swarm optimization (LR- PSO) technique in scheduling the units and maximizing the profit generation companies (Gencos). It mentions the significance of the advancement of power system engineering education and research. It further discusses the effectiveness of the technique.

The article presents a study which proposes a simple method for the microprocessor implementation of Selective Harmonic Elimination (SHE) pulse width modulation (PWM) based on curve fitting and conventional Newton iteration technique. Under the proposed online control technique, the SHE inverter output has 12 switching instants that eliminate 3rd to 23rd harmonics from the inverter. It demonstrates the application of the method on 1ph, 230V, 5kVA IGBT based voltage source inverter (VSI).