Shivam Kumar Yadav

In this paper, a reduced switch approach with cross clamped multilevel configuration is presented for high power penetration in the utility grid. The cross arm converter gives a new solution to feed MW scale power with fewer count of semiconductor switches. The less device approach makes it a compact solution with modular functionality to handle power efficiently. A cross arm connects two solar PV arrays with only six switches to have symmetric level contribution in converter voltage. Topological level explanations and modes of converter modules are presented for the 13‐level based new renewable energy system. Each cross connected module operates two PV arrays in individual MPPT mode to feed power efficiently. Efficiency enhancement is ensured with the nearest level round function to provide a fundamental switching logic. Fundamental modulation ensures fewer losses in switching transitions and efficient power control is achieved in day and night duration. Active and reactive power dynamics are shown to ensure reactive power compensation under sudden changes in grid voltage levels. Dynamic performance assessment shows that the converter operates smoothly with changes in irradiance set points. The system is modelled in MATLAB and RT‐LAB environments, testing MW‐scale feasibility of the new solar multilevel configuration for high power applications.

An improved multicarrier modulation technique is presented for single-source cascaded H bridge based solar multilevel converter (SMLC). Main aim of this article is to improve harmonic profile at converter output voltage. New modulation is introduced, which is summation of pulse and triangular carrier functions to have a new modified level arranged carrier scheme (MLACS). In MLACS, frequency of pulse function is S_f times carrier wave. Comparative Fourier investigation of MLACS and LACS is discussed. It is implemented in closed loop for enhancing power quality of SMLC at grid end. Comparison of new scheme is done with level arranged carrier scheme, phase-shifted carrier scheme (PSCS), and parabolic level arranged carrier scheme in under and over modulation ranges. MLACS efficacy is investigated in terms of weighted total harmonic distortion for five level output. Presented results at laboratory level validate MLACS concept for improved harmonic performance of SMLC.

A new configuration for integration of large-scale solar photovoltaic plant (LSPV) with a medium voltage (MV) grid (Typically 11 kV) is presented. This modular multilevel converter topology uses four cells with 1:3 (trinary) PV voltages in each phase to have seventeen levels in pole voltage. Each module has two PV arrays with six switches to have 5 levels (0, +V _pv , +2V _pv , +3V _pv , +4V _pv ). Presented configuration has lower total standing voltage for higher level switching states. Converter uses new modules to effectively control power in closed loop and with improved power quality (meeting the IEEE grid code 519). Control for maximum power, inverter independent power control and switching control are detailed. A round function-based evaluation is done to switch using nearest level switching scheme (NLSS). Converter is tested with a change in real-weather solar profile. Obtained results manifest's that large-scale power is transferred to MV grid perfectly with real-time geographical analysis of Bhadla Solar Park (Lattitude:27.5176° N, Longitude: 71.9304° E). Indices such as global average irradiance test case (GAI), direct average irradiance test case (DAI), and diffuse average irradiance (DFAI) are used as test cases. Moreover, investigation with European efficiency analysis validates practicability of large-scale solar PV system.

This work presents a new medium voltage nine-level solar converter, which uniquely connects the three-leg converters. The output terminal connects the voltage source converter (VSC) to the upper switch of next VSC. Moreover, photovoltaic (PV) arrays are connected in series with a negative terminal connected to positive DC rail of next VSC. This approach utilizes a common PV array for a three-phase system, which reduces the installation and maintenance cost on PV side. To deliver same amount of megawatt power in a nine-level line voltage, cascaded H bridge (CHB) requires six PV arrays (two in each phase). However, this converter utilizes only four PV arrays with nine levels line voltage at same power rating. The maximum power point tracking (MPPT) and proportional integral (PI) voltage regulators are reduced in this configuration, making the controller simple to tune in closed loop. The intermittent solar and grid voltage fluctuations are considered for testing the system's performance. The economic aspects of presented topology are discussed with a cost function. Moreover, test results validate operation of a new high power solar multilevel converter (MLC) with excellent dynamic performance.

This paper uses Levenberg-Marquardt Algorithm (LMA) for calculation of the accurate angles from the initial guess to have new control for solar PV system. This algorithm provides a new approach towards the evaluation of switching angles from the desired harmonic curtail function. The obtained angles provide the minimization of specific harmonics for solar photovoltaic system. The specific harmonic elimination (SHE) method with LMA algorithm is presented to eliminate low order harmonic component. The obtained angles are further used for closed loop grid-tied control of magnetically linked five-level CHB-PV topology. A lesser harmonic converter voltage is achieved and system is tested in intermittent solar profile. Results on computer simulation and hardware test bench showcase the effectiveness of the presented concept for improved control of solar multilevel inverters.

A fifteen-level packed U cell (FLPUC) converter with eight active switch counts for the grid-connected solar photovoltaic (GCSPV) application is introduced in this work. This converter has eight active switches with a PV source and two floating capacitors. This topology takes an edge over conventional configurations in terms of components required to achieve fifteen levels in converter output voltage. The mode of operation and switching states of the fifteen-level PUC converter are presented in detail. The active and reactive powers (PQ) control is incorporated for a grid-connected PV configuration, which in turn helps in an independent control over power injection into the grid. The maximum power operation is achieved for the first source connected to the PV array with the perturb and observe (P&O) MPPT technique and unity power factor is attained at the AC side. The voltages of floating capacitors are balanced at reference values using proportional-integral (PI) controllers to attain proper achievement of desired output voltage levels. Performance of the FLPUC based single-phase grid-tied system is analyzed under a constant and variable solar environment. This topology is modeled in MATLAB/Simulink, and test results are validated using real-time emulator to meet the IEEE-519 standard for power quality improvement.

This paper presents a new solar multilevel converter (SMLC) with closed-loop control to integrate solar PV arrays with medium voltage 3.3 kV grid. This multilevel converter produces higher number of levels in the output voltage with less usage of semiconductor switches. This solar converter utilizes only ten switches and three PV sources with equal voltage to have seven levels in the output voltage. The main motive is to have minimum switches, which reduces the count of driver circuits for a power converter. Moreover, a reduced switch converter requires less space in terms of installing the power and auxiliary components. This solar power converter comprises a solar photovoltaic (SPV) array fed level building network (LBN) nested within the six switches connected in a rectangular arrangement. The converter has two PV sources at its upper and lower ends. This solar converter is also ideal for asymmetric configurations. Moreover, the increase in solar input power is possible with more count of the LBNs. The converter switching states and operating path demonstrate the working operation of the new solar PV system. A comparison of the proposed solar converter is made with existing multilevel topologies. The system is modeled and executed in closed-loop control to showcase its effectiveness for solar power conversion. The solar converter transfers the power in varying solar conditions successfully.

A new multi-objective minimal-drift maximum power point tracking (MOMD-MPPT) technique is introduced to harness maximum power from single photovoltaic (PV) array fed multilevel converter (MLC). A drift in voltage arises with conventional MPPT techniques, which is minimized in this work with a new multi-objective solution. A new swarm optimization algorithm (NSOA) is used for MPPT, which combines the concept of swarm intelligence and pressure gradient force. It provides a minimal drift phenomenon for the solar MLC. Acceleration factor of the swarm particles in NSOA relies on pressure difference and distance. It leads to smoother convergence towards the operating point without trapping in the local minima. The presented algorithm is compared with well-known MPPT algorithms. Simulated results analyze the performance of MOMD-MPPT considering upper and lower voltage drift for PV fed MLC. Later, this algorithm is experimentally validated for a single PV array fed grid-tied multilevel converter. Recorded results show that the algorithm has minimal drift and improves the system performance in dynamic solar conditions.