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In this paper, FPGA(Field Programmable Gate Array) hardware-in-loop co-simulation (Hardware co-simulation)is proposed for controller prototyping of Cascaded H-bridge multilevel inverter(CHBMLI). Third harmonics injected pulse width modulation(THIPWM) technique is used for controller prototyping. Mathematical analysis of THIPWM control is investigated for improved dc bus voltage utilization and extension of linearity range. Control model of THIPWM for five and seven level inverter incorporating Phase shifted and level shifted carrier signals are generated using Xilinx system generator(XSG) platform in Matlab/simulink. Real time Hardware co-simulation is performed by modelling CHBMLI system in Matlab/simulink and hardware co-simulation is performed using Zedboard Zynq development and evaluation FPGA kit.

In this paper, cascaded H-bridge multilevel inverter (CHBMLI) based distribution static compensator (DSTATCOM) has been proposed. Synchronous reference frame theory (SRFT) based indirect current control is employed to extract the reference current. The instantaneous error in between the reference current and output current is processed through multiband hysteresis current controller (MHCC) for inner current control loop of DSTATCOM. MHCC algorithm requires switching pattern which leads to the generation of multilevel output for the inverter. DSTATCOM executes task like compensation of reactive power, harmonic compensation and load balancing. LCL filter is designed and employed to interface the multilevel inverter and grid, due to its advantage of low cost, smaller size, superior attenuation capability. The performance of CHBMLI based DSTATCOM model simulated in MATLAB-Simulink has been investigated and analyzed under different load condition.

This paper investigates the problems associated with distribution system in terms of delivery of clean power and their solutions, in particular the reactive power compensation. The abnormalities in the distribution system has been modeled and analyzed. The deviation so computed has been compensated by use of the D-STATCOM in the real time. A detailed model of 3-phase D-STATCOM for line voltage up to 11kV has been developed using cascaded multilevel voltage source converter structure (VSCs). A level shift PWM control has been developed for the multilevel inverter for the medium voltage distribution system. The scheme has been replaced for the control of the D-STATCOM so that it maintains the reactive power and THD under control by keeping all the voltage and current waveforms as per their standard sinusoidal forms. A SIMULINK model using MATLAB/SIMULINK platform has been used to present the proposed system. Simulation result for different operating condition has been obtained and analyzed for viewing the merit of the proposed control technique. The obtained results corroborate the effectiveness of control scheme.

Three-phase two-level voltage source converters are used for distribution static compensator (DSTATCOM) applications and can be replaced by a multilevel inverter. In this paper, an LCL filter interfaced cascaded H-bridge multilevel inverter-based (CHBMLI) DSTATCOM is simulated and its performance is analyzed considering the system parameters. The analysis considers factors including the switching frequency, modulation index, and filter parameters of a DSTATCOM system. The LCL filter design and analysis for the low switching frequency operation of CHBMLI is proposed in this paper. Phase shift pulse-width modulation is used for the generation of switching signals. The reference current is generated using synchronous reference frame theory (SRFT) for reactive power and harmonic compensations. The simulation model of the CHBMLI-based DSTATCOM system is developed in MATLAB Simulink. The results are demonstrated for a linear/non-linear load under unbalanced conditions, considering the voltage sag and swell in the system due to a disturbance in the load.

In this paper cascaded H-bridge multilevel inverter (CHBMLI) has been investigated for the application of renewable energy generation. Energy sources like solar, wind, hydro, biomass or combination of these can be manipulated to obtain alternative sources for renewable energy generation. These renewable energy sources have different electrical characteristics like DC or AC level so it is challenging to use generated power by connecting to grid or load directly. The renewable energy source require specific power electronics converter as an interface for conditioning generated power .The multilevel inverter can be utilized for renewable energy sources in two different modes, the power generation mode (stand-alone mode), and compensator mode (statcom). The performance of the multilevel inverter has been compared with two level inverter. In power generation mode CHBMLI supplies the active and reactive power required by the different loads. For operation in compensator mode the indirect current control based on synchronous reference frame theory (SRFT) ensures the grid operating in unity power factor and compensate harmonics and reactive power.

1. Introduction||2. Cascaded H-bridge Multilevel Inverter And FPGA Hardware Co-simulation||3. LCL filter interfaced DSTATCOM||4. Multiband Hysteresis Current Controlled CHMLI||5. Multiband HCC for Cascaded H-bridge inverter based DSTATCOM||6. Conclusion, 九州工業大学博士学位論文 学位記番号：生工博甲第310号 学位授与年月日：平成30年3月23日, 平成29年度