Polyphase Sequences Design-Using MSAA

This research compared the performance of PWM (Pulse Width Modulation) inverter and multilevel inverter in terms of their output voltage and current total harmonic distortion (THD). The inverters were designed to have the output voltage of 220 V at 50 Hz. The input voltage for both inverters are 400 VDC. For PWM inverter, the PWM technique utilized was sinusoidal PWM (SPWM) and for multilevel converter, the number of voltage level is five with diode-clamped topology. The study included circuit implementation, analysis, and THD calculation, all of which were carried out through simulation using PSpice software. In controlling the SPWM inverter output, the adjusted parameters included amplitude modulation ratio, frequency modulation ratio, and filter components’ parameters. On the other hand, the firing angles of the switching components were designated as controlling parameters in multilevel inverter. From the study, it was found that the best THD values of the designed SPWM inverter are 4.2% (voltage) and 1.7% (current), while those of multilevel inverter are 27% and 11%, for voltage and current, respectively. Thus, it can be concluded that SPWM inverter is better than 5-level inverter for the application in solar panel due to its lower THD. In our study, 5-level inverter did not satisfy the THD requirement specified in IEEE 512-1992, i.e. 5%.

The inverters and control methods are applied in more and more fields with power electronics development. The technology of current hysteretic band PWM is a kind of easy and reliable control method. But the harmonic distortion of load current is big amplitude around switching frequency side band. The paper introduce a Varied Hysteretic-band Current control technique(VHBCC), this method can spreads the spectrum contents of load current around switching frequency side band, reduces the harmonic distortion of load current . At last, The results of simulation prove the method feasible and effective.

An integrated DC to AC converter is proposed based on the Sinusoidal Pulse Width Modulation (SPWM) control principle in order to implement the conversion process. The proposed circuit consists of 4 stages. The first stage is a DC-DC converter to boost up the V dd voltage. A 5-stage Dickson charge pump has been chosen in order to achieve a maximum voltage gain of 6V dd . The second stage is an H-bridge, which receives the output voltage of the Dickson charge pump, for inverting the DC voltage to an SPWM signal. It consists of 4 MOS switches whose control is performed by the control unit, which produces two control signals. The control stage consists of two comparators; each comparator compares a sinusoidal signal with a triangular signal and produces a PWM waveform for controlling the H-bridge. The last unit is a low-pass filter, for converting the SPWM signal to an AC output voltage. The use of the output filter is very important for reducing the Total Harmonic Distortion (THD) of the DC-AC inverter output-voltage waveform. The proposed converter was designed by using a 0.35um high voltage technology, with conversion potential from V dd =1V-5V to V out =42,22Vp.p-311,8Vp.p (110V RMS ) at frequency f out =60Hz-2000Hz for driving electroluminescent (EL) lamps. The proposed implementation of the integrated DC-AC converter exhibits lower power consumption, lower input voltage and smaller silicon area compared to previous ones, while keeping THD and output ripple at very low values.

Since last decades, the pulse width modulation (PWM) techniques have been an intensive research subject. Also, different kinds of methodologies have been presented on inverter switching losses, inverter output current/ voltage total harmonic distortion (THD), inverter maximum output of DC bus voltage. The Sinusoidal PWM is generally used to control the inverter output voltage and it helps to maintains drive performance. The recent years have seen digital modulation mechanisms based on theory of space vector i.e. Space vector PWM (SVPWM). The SVPWM mechanism offers the enhanced amplitude modulation indexes (MI) than sinusoidal PWM along with the reduction in the harmonics of inverter output voltage and reduced communication losses. Currently, the digital control mechanisms have got more attention than the analog counterparts, as the performance and reliability of microprocessors has increased. Most of the SVPWM mechanisms are performed by using the analog or digital circuits like microcontrollers and DSPs. From the recent study, analysis gives that use of Field Programmable Gate Arrays (FPGA) can offer more efficient and faster solutions. This paper discusses the numerous existing research aspects of FPGA realization for voltage source inverter (VSI) along with the future line of research.

This paper presents a single-phase five-level inverter controlled by two novel pulse width modulation (PWM) switching techniques. The proposed PWM techniques are designed based on minimum switching power loss and minimum total harmonic distortion (THD). In a single-phase five-level inverter employing six switches, the first proposed PWM technique requires four switches to operate at switching frequency and two other switches to operate at line frequency. The second proposed PWM technique requires only two switches to operate at switching frequency and the rest of the switches to operate at line frequency. Compared with conventional PWM techniques for single-phase five-level inverters, the proposed PWM techniques offer high efficiency and low harmonic components in the output voltage. The validity of the proposed PWM switching techniques in controlling single-phase five-level inverters to regulate load voltage is verified experimentally using a 100 V, 500 W laboratory prototype controlled by dspace 1103.

Conventional Sinusoidal Pulse Width Modulation (SPWM) topology is one of the essential Pulse Width Modulation (PWM) topologies used in Voltage Source Inverter (VSI) applications such as adjustable speed motor control, Uninterrupted Power Supplies (UPS) and Photovoltaic (PV) Systems. Although conventional SPWM is used in VSI applications, the output voltage waveform of VSI based on this topology contains a high content of harmonic distortion. Hence, this paper presents a modified SPWM topology with an Artificial Neural Network (ANN) technique. The ANN technique was applied to minimize the Total Harmonic Distortion (THD) present in the output voltage waveform of the VSI. The proposed system was designed and evaluated with MATLAB/Simulink software. Based on the comparative evaluation, the paper proves that the proposed system contributes to a 9.1 % reduction in the THD value of a three-phase two-level VSI's output voltage waveform.

A voltage source inverter with variable frequency and variable voltage is applied for three-phase interior permanent magnet synchronous motor (IPMSM) drive for variable speed application. To obtain the required output voltage in the line side of the inverter a suitable pulse width modulation technique is used. The most prominent PWM techniques are Sinusoidal pulse width modulation (SPWM) and Space vector pulse width modulation (SVPWM). SPWM is simple and easy method to generate pulses for inverter, whereas SVPWM is an accurate method and generate less harmonic distortion compared to SPWM. However there is a lot of complexity involved in calculation of angle and sector as the level increases with SVPWM. To overcome this a similar and easy method known as unified pulse with modulation also know as carrier based space vector pulse width modulation technique(CBSVPWM is described using the concept of effective time. By using this method the inverter output voltage is directly synthesized by the effective times and the voltage modulation task can be greatly simplified. In this paper an IPMSM drive using CBSVPWM is simulated using MATLAB/SIMULINK software and its performance is compared with SPWM by varying modulation index (MI). The simulation study reveals that CBSVPWM simple and easy method which utilizes dc bus voltage more effectively and generates less THD compared to SPWM.

In the single-phase grid-connected inverter systems the high quality Total Harmonic Distortion (THD) factor must always be considered. In cases, when the supplying voltage is reduced, the output voltage can still be assured constant in the limited range by using the over-modulation strategy that also enables better utilization of dc bus. Unfortunately, this operation incurs high order harmonics' force into the inverter output voltage, which is a huge drawback in almost all industrial applications. This paper provides a comprehensive spectrum analysis of three-level output voltage in a single-phase inverter in an over-modulation working regime. The output voltage is generated by triangular Sinusoidal Pulse-Width Modulation (SPWM) and, based on the analytical results of a frequency spectrum evaluation the dominant 3rd harmonic could be eliminated while the rest higher harmonics can be easier attenuated by using smaller output filter and the THD is lower in the wide range.

Power electronic converters for medium and high power / voltage applications employ low frequency synchronous fundamental switching to minimize semiconductor switching losses. There are two major approaches to converter switching angles determination - Selective Harmonic Elimination (SHE) and Total Harmonic Distortion (THD) minimization. For the THD minimization, converter switching angles are found to assure minimum THD criterion without taking care of frequency spectrum. For the SHE approach, all degrees of freedom due to available amount of switching angles are spent on elimination of low order harmonics. Recently suggested combined approach suggests spending some degrees of freedom on certain harmonics elimination and the rest for minimizing THD. This generalized problem formulation includes classic minimal THD and SHE problems as special cases. The paper presents comprehensive results on combined SHE and THD minimization for a staircase modulation of a single-phase converter with 5, 6, 7 and 8 switching angles (6, 7, 8 and 9 non-negative voltage levels).

In this study, an extended Lyapunov-function-based control strategy that assures global asymptotic stability is proposed for single-phase UPS inverters. The Lyapunov function is formed from the energy stored in the inductor and capacitor due to the fact that the system states converge to the equilibrium point if the total energy is continuously dissipated. It is shown analytically that the classical Lyapunov-function-based control leads to a globally asymptotically stable system at the expense of steady-state errors in the output voltage, which exist due to the lack of outer voltage loop in the control input. Therefore, an extended Lyapunov-function-based control strategy is proposed, which eliminates the steady-state error without destroying the global stability of the closed-loop system. The steady state and dynamic performance of the proposed control strategy has been tested by simulations and experiments under resistive and diode bridge rectifier loads. The results obtained from a 1-kW inverter demonstrate that the developed control strategy not only offers global stability, but also leads to good quality sinusoidal voltage with a reasonably low THD, almost zero steady-state error in the output voltage, and fast dynamic response under linear and nonlinear loads.

Harmonic distortion caused by nonlinear loads is a significant challenge in power systems, often resulting in reduced efficiency, overheating, and equipment malfunction. Despite the availability of various mitigation techniques, many fail to offer a cost-effective and practical solution for distribution networks. This research addresses that gap by designing and analyzing a five-stage single-tuned passive filter (STPF) system to mitigate harmonics in a 400V, 50Hz distribution network. The main objective is to reduce Total Harmonic Distortion (THD) in voltage and current to meet IEEE 519-2022 standards. The proposed filter system targets the 5th, 7th, 9th, 11th, and 13th harmonic orders using a simulation model developed in MATLAB/Simulink. The system initially showed high THD levels of 16.06% in voltage and 17.57% in current. After applying the filters, the voltage THD was reduced to 3.89%, and the current THD dropped to 2.52%. These results confirm the effectiveness of STPFs in improving power quality under nonlinear loading conditions.

In this paper, a new switching strategy is proposed for a multi-level STATCOM system. An efficient approach in reducing the harmonic contents of the inverter's output voltage is total harmonic distortion (THD) minimization. In multilevel inverters with fundamental frequency switching strategy (each switch turning on and off once per output cycle), the switching angles can be selected such that the output THD is minimized. In three phase multilevel inverters, the optimization algorithm is commonly applied to the phase voltage of the inverter. This results in the minimum THD in phase voltage, but not necessarily in the line to line minimum THD. In this paper, THD minimization process is directly applied to the line to line voltage of the inverter, and a new control strategy of multilevel STATCOM is proposed. The proposed method will be implemented, in RTDS and the closed loop operation of multi-level STATCOM will be explored.

Analysis and enhancement of PV efficiency with incremental conductance MPPT technique under non-linear loading conditions

Photovoltaic energy is a clean and endless vital renewable energy. In order to generate electricity from solar energy an inverter is required to transform the direct current into alternating current. Also, with the emerging of new ultra-high voltage direct current transmission technology, the rectification and inverters play a great role. Most three phase two-level inverters draw harmonics that cause heat dissipation, waveform distortions hence affect the electrical loads. Knowing that Total Harmonic Distortion content of voltage source inverter is important and must be within the allowable range. Several schemes are suggested to mitigate the distortion in order to produce as much a sinusoidal output signal as would be possible. The most widely used control process of the semiconductor switches is Pulse Width Modulation technique. One of such schemes is using a Sinusoidal Pulse Width Modulation -based inverter which is usually used in inverters for industrial applications. In this paper, a study of the performance of the SPWM technique is presented for a three-phase H-bridge inverter and the simulation results obtained in MATLAB/Simulink demonstrate that the significantly investigation on the harmonics when varying the modulation index. These results confirm that the total harmonic distortion factor of the inverter output voltage decreases as the modulation index increases as a result, reduces the waveform distortion rate and suppresses the effects of harmonics. This is of great significance for the safe, stable, and efficient operation of the power system.

Modern low-voltage frequency converters, built on the principle of stand-alone inverters with pulse-width modulation, have large amplitudes of higher harmonics in the output voltage. This adversely affects the operation of an asynchronous or synchronous motor connected to such a converter, since it causes a decrease in the efficiency of the AC machine. The analysis of the reasons for the poor harmonic composition of the output voltage of traditional inverters with sinusoidal pulse-width modulation is carried out and it is noted that the main one is the introduction of "dead" time when switching half-bridges every modulation period. The proposed method of sinusoidal modulation does not require the introduction of "dead" time. The modes of operation of power transistors with this switching method and control signal diagrams are considered. Analytical expressions are found that make it possible to determine the effective value of the output voltage of the frequency converter and the coefficients of higher harmonics for the proposed method of switching power transistors. The main reason for the low effective value of the phase voltage at the output of the inverter at sinusoidal pulse-width modulation is determined - the ineffective use of the switching period. The proposed method of sinusoidal modulation does not require the introduction of "dead" time, increasing the effective value of the output voltage and reducing the total harmonic component by 75 times. The diagrams of signals that control power transistors and provide a decrease in the amplitudes of higher harmonics at the output of the frequency converter are given. An approximation by the harmonic Fourier series of the output voltage of the inverter, obtained in the case of using the proposed method of switching power transistors, is made. It is noted that for the technical implementation of sinusoidal modulation, which provides small amplitudes of higher harmonics, only two pulse-width modulators are needed.