Comparative performance of modular with cascaded H-bridge three level inverters (original) (raw)
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CASCADED H-BRIDGE MULTILEVEL INVERTER FOR INDUCTION MOTOR DRIVES
This paper proposes a cascaded H-Bridge Multilevel inverter for induction motor drives. Multi-level Inverter (MLI) has several advantages over conventional inverter such as lower total harmonic distortion (THD), low switching loss, good power quality, high output voltage. The main feature of multilevel inverter is that it uses many small dc sources to supply various output levels. The Hbridge cascaded MLI is chosen in this paper because it requires least number of components for same voltage level. The H bridge cascaded MLI with five levels is designed. The simple multi carrier SPWM techniques namely phase disposition (PD) is used to generate pulses for the MLI. The H-bridge cascaded MLI with five levels using PD modulation technique is designed for induction motor drives. The performance of designed MLI fed induction motor drives is investigated extensively for various operating conditions through MATLAB simulation. The performance of MLI is also compared with conventional three phase inverter in terms of THD. The promising and interesting results obtained are comprehensively presented.
Huge electric drives need advanced power electronics converter to meet their power demands. Consequently, multilevel power inverter structure have been introduced .A multilevel converter has many advantages such as high power ratings, improvement in the performance of the system in terms of reduced harmonics and dv/dt stresses etc . There are so many topologies of multilevel inverter described in the literature; however we are using cascaded H-bridge multilevel inverters with reduced no. of switches as it is the most practicable topology to use as a power converter for medium & high power application. Induction motor drives are the most common used ac motors in industries because it is cheap, robust, efficient and reliable. This paper deals with the comparison of cascaded 7 level, 9 level and 11 level multilevel inverter for induction motor drive. Here sinusoidal pulse width modulation technique is used. THD and Motor parameters are analyzed. Simulation using MATLAB/ Simulink has been performed to verify the performance of multilevel inverters.
Analysis of Three and Five Level Half-Bridge Modular Multilevel Inverter
2014
The multi level inverters are mainly classified as Diode clamped, Flying capacitor inverter and cascaded multi level inverter. The cascaded H-bridge multilevel control method is very easy when compare to other multilevel inverter because it doesn‟t require any clamping diode and flying capacitor. The simulation had been carried for single leg of three phase three and five level Half-bridge modular multilevel converter (MMC) by using submodules. The main objective of this paper is to analyse operation of Half-bridge MMC for different level of voltage by using SPWM technique which reduces total harmonic distortion and enhances output voltage and current closer to sinewave without adding any complexity to the power circuit.
ANALYSIS OF CASCADED H-BRIDGE MULTILEVEL INVERTER WITH LEVEL SHIFTED PWM ON INDUCTION MOTOR
Multi-level converter technology has emerged as a very important alternative in the area of high-power medium voltage energy control. Two level inverters are those which creates a voltage or a current with levels either 0 or ±V dc. To achieve an eminence output voltage or a current waveform with a lowest amount of ripple content, they need high switching frequency. When working at high frequency, high power and high voltage applications these two level inverters have a few restrictions. The multi-level inverter is to produce a quasi sinusoidal voltage from many levels of dc voltages. The obtained output waveform has more steps, which creates a staircase wave form that reaches to a preferred wave form, as the number of levels increases. By the on and off the power switches a sequence of pulses can be produced by using SPWM or sinusoidal pulse width modulation technique which is widely used in power electronics. Sinusoidal pulse width modulation is widely used in many industrial applications and also used for so many years and it is characterized by constant amplitude pulses with dissimilar duty cycle for every period because of its circuit ease and strong control mechanism. To minimize the harmonic content and to control the output voltage of inverter the width of this pulses are modulated. Many PWM techniques are present to regulate the motor, but out of that Sinusoidal pulse width modulation or SPWM is the typically used scheme in motor control and inverter application. Finally a unipolar and bipolar SPWM voltage modulation technique is proposed because this method offers the benefit of successfully doubling the switching frequency of the inverter voltage, thus creating the output filter smaller, economical and trouble free to implement.
Analysis of Multilevel Inverter using Bipolar and Unipolar Switching Schemes with Induction Motor
Cascaded H-bridge Multilevel Inverter (MLI) is most efficient topology for medium and high voltage DC-AC conversion, having less output harmonics and less commutation losses. Disadvantages are their complexity, more number of power devices, passive components and a complex control circuitry. Here a Cascaded Hybrid Multilevel Inverter is used to produce a three phase 9-level output voltages. Now a day inverter is also know as a DC-AC converter, is one of the most popular part of electrical device. This proposed inverter widely used in industries application such as speed control of induction motor. This thesis focus on three phase 9-level bipolar and unipolar switching inverter with characteristics like output voltage boosting ability and also we discus about the bipolar and unipolar switching scheme along with capacitor voltage control. The modified topology uses Cascaded H-bridge (CHB) with bidirectional and unidirectional switches producing boost up output voltage. Here a hybrid Pulse Width Modulation (PWM) technique is applied to control the power devices. This modulation technique uses a sine wave and a repeating wave, these waves are combined and a complete reference wave is generated. There is comparative study between CHB and modified topology between number of power devices used and Total Harmonic Distortions (THD). THD of modified topology is reduced and analyzed by FFT window. The results are observed by MATLAB/SIMULINK software.
Investigation Study of Three-Level Cascaded H-bridge Multilevel Inverter
This paper analyzed three-level Cascaded H-bridge Multilevel Inverter (CHMLI) utilizing two modulation techniques namely Sinusoidal Pulse Width Modulation (SPWM) and Space Vector Pulse Width Modulation (SVPWM). The performance and the output of CHMLI in terms of Total Harmonic Distotion (THD) % and circuits complexity were compared. The simulations models were constructed using MATLAB/SIMULINK. The results showed the CHMLI produced the lowest THD contents and utilized fewer components. Moreover, the SVPWM produced less THD than SPWM.
This paper proposes comparison between symmetrical and asymmetrical Cascaded H-Bridge Multilevel Inverter (CMLI) using the multicarrier based SPWM Technique with induction motor as a load. Multilevel inverter have become more popular over the years in high power medium voltage application without the use of the transformer and with less disturbance & reduced harmonic distortion. In this paper three phase configuration of cascaded h-bridge multilevel inverter are studied. Here, carrier based sinusoidal pulse width modulation (SPWM) Technique is used as the modulation strategy. In this modulation strategy include the phase disposition technique (PD), phase opposition disposition technique (POD), and an alternative phase opposition disposition technique (APOD). All the study of the technique has been carried out the MATLAB/SIMULINK and evaluation of CMLI using SPWM technique in terms of THD. Keywords Cascaded H-bridge multilevel inverter (CMLI), Sinusoidal pulse width modulation (SPWM) technique, and Total harmonic distortion (THD).
2013 International Conference on Electrical Machines and Systems, Oct. 26-29, 2013, Busan, Korea, 2013
Development of electrical vehicle (EV) and hybrid electrical vehicle (HEV) gives many opportunities and challenges in power electronic drive, especially in the development of traction motor drive that requires advanced power electronic inverter. Multilevel inverter was first proposed by Nabae in early 1980. The general structure of the multilevel inverter is to synthesis a sinusoidal voltage out of several levels of dc voltages. This paper shows comparison between the 3-Level Cascaded H-Bridge Multilevel Inverter and 5-Level Cascaded H-Bridge Multilevel Inverter. It is found that by using 5-level Cascaded H-Bridge Multilevel Inverter (CHMI) can reduce torque and flux ripples compare to 3-Level CHMI and hence can improve DTC performances.
COMPARATIVE ANALYSIS OF MULTILEVEL INVERTER TOPOLOGIES FOR INDUCTION MOTOR DRIVE APPLICATIONS
Induction motors are widely used in industries, because they are rugged, reliable and economical and hence they are called as work horse power of industry. Induction motor drive requires suitable converters to get the required speed and torque without or negligible ripples. Multilevel inverters can do this job. But the conventional MLIs such as Diode Clamped MLIs requires extra diodes in conjunction with the active switches, Flying capacitor MLIs requires extra Capacitors and control also difficult if the levels increases and the Cascaded H-bridge MLIs requires separate dc sources which limits its use. This paper proposes a new type of multi level Inverter which converts the dc into ac using less number of switches when compared to conventional multilevel Inverters. The proposed Inverter uses only seven switches to get 13-level output voltage compared conventional cascaded H-bridge uses twelve switches. The comparison between the conventional MLIs and proposed inverter is presented in this paper. Finally the induction motor using proposed inverter with thirteen level is simulated using Matlab/Simulink environment and the corresponding results are presented in this paper.
Multilevel inverters have become a promising power conversion technology for number of applications in renewable energy systems, flexible ac transmission systems and high voltage direct current systems. For a medium voltage grid, it is troublesome to connect only one power semiconductor switch directly as voltage stress on the switch increases its lifespan gets decreased. As a result, a multilevel power inverter structure has been introduced as an alternative in high power and medium voltage situations. The three main topologies in Multilevel inverters are Diode clamped(Neutral clamped), Flying capacitor(capacitor clamped) and cascaded H-Bridge type. Of the above mentioned three the cascaded H-bridge has become popular due to its simpler design and modular property. Further the cascaded H-bridge type can be classified into two types on the basis of equality of input DC sources into Symmetric and Asymmetric cascaded inverters. This paper presents the comparison of symmetric five level inverter and Asymmetric seven level inverter. The symmetric topology consists of two equal DC sources and the Asymmetric topology consists of two DC sources which are in the ratio of 1:2. The two topologies are simulated in MATLAB/Simulink and the results are obtained by connecting these topologies to asynchronous induction motor.