scholarly journals Simplified Space Vector Pulse Width Modulation based on Switching Schemes with Reduced Switching Frequency and Harmonics for Five Level Cascaded H-Bridge Inverter

Author(s):  
B. Sirisha ◽  
P. Satishkumar

This paper presents a simplified control strategy of spacevector pulse width modulation technique with a three segment switching sequence and seven segment switching sequence for high power applications of multilevel inverters. In the proposed method, the inverter switching sequences are optimized for minimization of device switching frequency and improvement of harmonic spectrum by using the three most desired switching states and one suitable redundant state for each space vector. The proposed three-segment sequence is compared with conventional seven-segment sequence for five level Cascaded H-Bridge inverter with various values of switching frequencies including very low frequency. The output spectrum of the proposed sequence design shows the reduction of device switching frequency, current and line voltage THD, thereby minimizing the filter size requirement of the inverter, employed in industrial applications, where sinusoidal output voltage is required.

Author(s):  
B. Sirisha ◽  
Dr. P. Satishkumar

This paper presents a simplified control strategy of SVPWM with a three segment switching sequence and 7 segment switch frequency for high power multilevel inverter. In the proposed method, the inverter switching sequences are optimized for minimization of device switching sequence frequency and improvement of harmonic spectrum by using the three most derived switching states and one suitable redundant state for each space vector. The proposed 3-segment sequence is compared with conventional 7-segment sequence similar for five level Cascaded H-Bridge inverter with various values of switching frequencies including very low frequency. The output spectrum of the proposed sequence design shows the reduction of device switching frequency and states current and line voltage. THD this minimizing the filter size requirement of the inverter, employed in industrial applications. Where  sinusoidal output voltage is required<em>.</em>


Author(s):  
Sreenivasappa Bhupasandra Veeranna ◽  
Udaykumar R Yaragatti ◽  
Abdul R Beig

The digital control of three-level voltage source inverter fed high power high performance ac drives has recently become a popular in industrial applications. In order to control such drives, the pulse width modulation algorithm needs to be implemented in the controller. In this paper, synchronized symmetrical bus-clamping pulse width modulation strategies are presented. These strategies have some practical advantages such as reduced average switching frequency, easy digital implementation, reduced switching losses and improved output voltage quality compared to conventional space vector pulse width modulation strategies. The operation of three level inverter in linear region is extended to overmodulation region. The performance is analyzed in terms THD and fundamental output voltage waveforms and is compared with conventional space vector PWM strategies and found that switching losses can be minimized using bus-clamping strategy compared to conventional space vector strategy. The proposed method is implemented using Motorola Power PC 8240 processor and verified on a constant v/f induction motor drive fed from IGBT based inverter.


2020 ◽  
Vol 8 (5) ◽  
pp. 5180-5185

Paper Setup must be in A4 size with Margin: Top In the present paper multi carrier sinusoidal modulation technique which is an efficient method of producing control signals is used for a symmetrical inverter with several levels in cascade H Bridge is discussed. The Cascaded H-Bridge performance output levels depend on the DC voltage sources used at the input side. With the help of two DC voltage sources, five level output can be obtained whereas three sources gives levels of seven in output voltage. In this paper, multi-carrier SPWM switching is obtained for switching of multilevel inverter based switches. Two signals are used in this switching method, among which one of the signals is reference which is a low frequency sinusoidal signal and the one is a carrier signal. In case of sinusoidal PWM method of modulation technique, the reference signal is a sinusoidal one and triangular signal can be used as a carrier signal. These types of inverters have the ability to generate inverted output voltage with an efficient harmonic spectrum and reliable output results. This document provides switching signal for H-bridge inverter structure which can improve harmonic performance. The 5-level multilevel inverter is simulated for traditional carrier-based pulse-width modulation (PWM) phase change carrier techniques. The total harmonic performance of the output voltages is analyzed for the two PWM control methods. The performance of the symmetrical PWM CHB is simulated using MATLAB-SIMULINK model. Model results show that THD can be minimized to a limit with level shifted modulation method of the sinusoidal pulse width. The results from the simulations show that the quality of the waveform of the output voltage improves with less loss and with a lower THD.


Author(s):  
Salman Ahmad ◽  
Rahim Uddin ◽  
Zahoor Ahmad Ganie

A microcontroller based pulse width modulation implementation for multilevel quasi Z source inverter is proposed in this paper. The component design of quasi z source inverter (qZSI) is first considered with continuous and discontinuous mode of operations. The low switching frequency operation of multilevel quasi Z source inverter is proposed in this paper. The detailed modelling for qZSI is then established for effective implementation of PIC microcontroller (PIC 16F877A) for generating the switching signals. A prototype of five level quasi z-source inverter have been developed and the control signal to the gate drivers have been applied by properly adjusting the shoot through and non shoot through switching states. The hardware result shows the effective implementation of the proposed scheme.


Energies ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7643
Author(s):  
Lingling Cao ◽  
Jiefeng Lin ◽  
Shikai Chen ◽  
Yuanmao Ye

Multilevel inverters have been widely used in various industrial applications such as renewable energy generation and electric vehicles. An improved circuit of symmetrical cascaded switched-capacitor multilevel inverter is proposed so that the reactive power is absorbed by its power supply instead of capacitors. Then, a special hybrid pulse width modulation strategy combing level-shifted pulse width modulation (LS-PWM) and phase-shifted pulse width modulation (PS-PWM) was developed for the inverter. With this modulation algorithm, the power between cascaded units is automatically balanced, and the voltage of the capacitor in each unit is also automatically balanced to the dc input voltage. In addition, the optimized capacitor voltage ripple makes it possible to use a smaller capacitor to produce a better output voltage waveform. Theoretical analysis, simulation and experimental results show that the equivalent switching frequency of the cascaded multilevel inverter is twice the original frequency so that the output voltage harmonics are only distributed near even multiples of the carrier frequency.


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