Durgesh Prasad Bagarty

This multilevel inverter methodology is the center of focus among researchers in recent era. It has been focused due to its advantages over existing topologies, drawbacks and improvement of power quality, Multi-level inverter has the ability to generate nearly sinusoidal waves. This sinusoidal wave can be further improved by increasing the level of output voltage or with the help of filter design, and this manuscript presents single-phase Multi cell Multi-Level Inverter (MLI). It has been considered for reducing component count to get a higher number of output voltage levels and lower Total harmonics distortion profile. It comprises with four symmetric DC input voltage and 10 IGBT switches to produces stepped output of 9 level, and when deploy asymmetric Dc voltage source the same circuit will produce 31 level output with some changes in firing scheme, moreover this circuit is the family of cascaded hybrid bridge inverter so this circuit covered advantage of CHB MLI, This circuit uses lower no. of switch as compared to existing conventional MLIs such as FC-MLI, CHB-MLI, NPC-MLI, This paper also provides one of most pertinent controls and modulation mechanisms for a MLI using a hybrid reference/carrier-oriented sinusoidal PWM mechanism. At last, simulated outcomes are to validate the performance of both architectures in MLI structure as well as verify the concept.

The phase and frequency correction with a three-phase grid-connected solar photovoltaic-distributed static compensator (SPV-DSTATCOM) is challenging. For grid-connected SPV-DSTATCOM, this paper proposes a cascaded enhanced second-order general integrator frequency locked loop with prefilter (CESOGI-FLL-WPF) controller. The suggested work uses the available SPV power to meet the active power requirement of local loads. Furthermore, after addressing the local load demands, the extra SPV power is pumped into the grid. The voltage source converter (VSC) operates as a DC/AC inverter when sunlight is available and as a DSTATCOM when sunlight is not available. As a result, the VSC contributes to reactive power compensation, improved power quality, improved power factor, zero voltage regulation, efficient load balancing, and increased device utilization. The CESOGI-FLL-WPF controller is able to extract the fundamental components from nonlinear load currents, resulting in superior harmonics compensation and a highly rapid and stable dynamic response of the overall system under varied conditions. The suggested system is modelled and simulated using the MATLAB/Simulink software. The proposed SPV-DSTATCOM prototype is tested in the laboratory to ensure that it performs as expected.

This work deals with a single-stage three-phase grid-connected solar photovoltaic distribution static compensator (SPV-DSTATCOM) under partial shading condition (PSC). During PSC, the SPV-DSTATCOM is connected to the distribution network to solve issues like active current sharing, reactive power control, and harmonic elimination. The conventional Proportional Resonant (PR) controller for SPV-DSTATCOM behaves as a notch filter at resonance frequency with high gain of magnitude and has less DC offset rejection capability. Here, an improved PR based on second-order generalized integrator (IPR-SOGI) control architecture with unity gain at the fundamental frequency and more DC offset rejection capability is presented to address the drawback of the conventional PR controller. The performance of the proposed controller is examined under different loading conditions in steady-state and dynamic conditions. Finally, a comparison between the proposed controller with the conventional PR controller and adaptive PR controller are provided with the experimental validation.

Vector control algorithms reported so far for stand alone operation of variable speed constant frequency double output induction generators propose to supply the full magnetisation current of the machine in addition to the torque producing component from the rotor side converter. As the rotor of a normal induction machine is not designed for this additional load this approach leads to underutilisation of the machine torque capacity. Moreover, supplying the entire magnetisation current from the rotor side is not optimal from the point of view of the machine losses. Since the load voltage is regulated by manipulating the magnetising current through a slow acting flux control loop undesirable fluctuations in the load voltage waveforms are observed during fast load transients. An improved stator flux oriented control strategy for this type of generators, proposed in this study, eliminates undesirable load voltage transients by directly regulating the stator flux through the stator side converter. The total reactive power demand of the system is dynamically distributed between the two converters according to an optimum allocation program so as to minimise the losses without disturbing the stator flux. The effectiveness of the proposed algorithms is verified experimentally on a laboratory prototype.