Modified Phase-Shifted PWM Scheme for Reliability Improvement in Cascaded H-Bridge Multilevel Inverters

The paper presents the design of Modular Multilevel Inverter (MMI) to control the Induction Motor (IM) drive using intelligent techniques for marine water pumping applications. The proposed inverter is of eleven level and has the ability to control the speed of an IM drive which is fed by solar photovoltaic's. It is estimated that the energy consumed by pumping schemes onboard ship is nearly 50% of the total energy. Considering this fact, the paper investigate and validates the proposed control design with reduced complexity intended for marine water pumping system employing an induction motor (IM) drive and MMI. The analysis of inverter is carried out with Proportional-Integral (PI) and Fuzzy Logic (FL) based controllers for improving the performance. A comparative analysis has been made with respect to better robustness in terms of peak overshoot, settling time of the controller and Total Harmonic Distortion (THD) of the inverter to show the effectiveness of the proposed scheme. Simulations are undertaken in MATLAB/Simulink and the detailed experimental implementation in real time with Field Programmable Gate Array (FPGA). The results thus obtained are utilized to analyze the controller performance, improved inverter output voltage, reliable induction motor speed control and power quality improvement by reduction of harmonics. The novelty of the proposed control scheme is the design and integration of MMI, IM drive and intelligent controller exclusively for marine water pumping applications.

Section: Experimental Analysismentioning

confidence: 99%

Fuzzy Logic Control for Solar PV Fed Modular Multilevel Inverter Towards Marine Water Pumping Applications

Stonier¹,

Murugesan²,

Samikannu

et al. 2021

“…The advantages of MLI include stepped output voltage resembling a sinusoidal wave [2]. Staircase output voltage waveform generated by the MLI lowers the harmonics and improves power quality [3]. The higher the level in the output voltage, the lower is the total harmonic distortion and, consequently, the losses associated with lower order harmonics in applications such as drives [4], [5].…”

Section: Introductionmentioning

confidence: 99%

“…At any instant of time, twelve switches are in ON state. This increases conduction losses considerably [3]. Assuming 0.5 volts drop across each switch, 12 switches during operation cause a drop of 6 volts and consequently, the power loss is quite high under higher current operation.…”

Section: Introductionmentioning

confidence: 99%

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A Hybrid Nearest Level Combined With PWM Control Strategy: Analysis and Implementation on Cascaded H-Bridge Multilevel Inverter and its Fault Tolerant Topology

Sarwar

Farooqui

et al. 2021

This paper presents a hybrid control strategy which combines the nearest level control technique with PWM control technique on a cascaded H-Bridge Multilevel Inverters (MLI). MLIs have become very popular due to its several adavantages in the application areas like industrial drives and gridconnected renewable energy generation systems. With the reduced number of switches, driver circuits, conduction losses, switching losses, voltage stresses, size, and cost of the system, MLI has outperformed its two-level counterpart in terms of power quality issues. Reduction in the Harmonics and consequently the Total Harmonic Distortion (THD) in the output voltage has added to the benefits of MLI. Topological advancements in MLI require a satisfactory output voltage control strategy. In this work, a hybrid control strategy for a smooth and wider range of control of output voltage is proposed. The hybridized scheme enhances the control range of the voltage considerably. Moreover, the THD is also reduced compared to the conventional sinusoidal PWM scheme. A thorough analysis of the scheme has also been presented in the paper. SIMULINK/ MATLAB environment is used for testing the simulation model of the proposed control scheme. This hybridized controlling technique is also simulated for thermal modelling on PLECS software and power loss analysis is performed. The mathematical and simulation analyses are validated on an experimental prototype using a TMS320F28335 DSP controller card. The hybrid scheme has also been tested for a fault tolerant model of the cascaded H-bridge inverter. The performance of the hybrid scheme under different fault condition has also been shown to work satisfactorily.

“…The clamping period, however, is assigned to a specific Hbridge leg and thus the power losses are not distributed evenly. In [19], a novel sinusoidal PWM (SPWM) was proposed and this method also adopted the clamping period. The reference signal for modulation is formed by mixing the sinusoidal wave and clamping period with rotation scheme.…”

Section: Introductionmentioning

confidence: 99%

An Improved Phase-Shifted DPWM Method for Reducing Switching Loss and Thermal Balancing in Cascaded H-Bridge Multilevel Inverter

Kim

Lee

et al. 2020

Self Cite

This paper proposes an improved discontinuous pulse-width modulation (DPWM) method based on phase-shifted PWM (PS-PWM) for three-phase cascaded H-bridge (CHB) multilevel inverters. Due to the CHB multilevel inverters employ a large number of power semiconductor switches, they suffer from device failures because the switches are one of the major failure factors in a power electronic system. Therefore, the reliability and lifetime of CHB multilevel inverters are mainly determined by the reliability of switches. The most failure of switches is occurred by its accumulated thermal stress which is generated by power losses including the conduction and switching loss. By applying the conventional DPWM, the lifetime of switches can be extended because it reduces the switching loss. The conventional DPWM, however, still operates with high speed carrier frequency and it is not enough to reduce the switching loss of the CHB multilevel inverter with a large number of inverter cells. The proposed novel DPWM method provides the improved switching loss reduction through the different switching behaviors for each leg. Additionally, the rotation scheme promises even power distribution and lifetime management among inverter cells in a CHB multilevel inverter. The simulation results and experimental results confirm the switching loss reduction and even power distribution abilities of the proposed modulation method. INDEX TERMS Discontinuous pulse-width modulation, Power losses, Power distribution, Cascaded Hbridge multilevel inverter, Reliability of power conversion system.