Nowadays, the use of superconductive magnetic energy storage (SMES) devices in grid integration are highly escalated with the technological amelioration of magnetic components. The power quality and energy conversion efficiency of the power conditioning system of the SMES and renewable energy systems depend on the control algorithms of the voltage source inverter (VSI). However, the traditional control schemes cause inferior response and conversion efficiency. In this paper, an advanced control technique named PI+LLC controller is proposed, which is based on the proportional integral (PI) controller and lead-lag compensator (LLC). The proposed control technique offers significant reduction in the total harmonic distortion (THD), superior dynamic response, smooth response against fault, excellent reference tracking capability of grid current and improved power quality performance at both inverter side and grid side for a 5-level neutral point clamped inverter based grid-tied photovoltaic system. It is expected that, the proposed control scheme can also be used to mitigate the excessive heat of the VSI based SMES system by improving the performance of the power conditioning system. The performance of the proposed control technique is evaluated in MATLAB/Simulink environment to validate the excellent features of the proposed control scheme.

Due to global warming and shortage of fossil fuels, the grid-connected solar photovoltaic (PV) system has gained significant popularity all over the world. The modular multilevel cascaded (MMC) inverter is the natural choice for step-up transformer and line filter less direct medium voltage grid integration of solar PV systems. However, power quality and loss are the important issues while connecting the PV system to the medium voltage grid through MMC inverter. Modulation technique is the key to maintain output power quality, e.g., total harmonic distortion (THD) and to ensure low switching and conduction losses. In this paper, an advanced modulation technique named “triangle saturated common mode pulse width modulation (TSCMPWM)” control is proposed for a 3-phase 5-level MMC inverter-based grid-tied PV system. Compared to traditional modulation techniques, the proposed TSCMPWM control offers the lowest voltage THD as well as lower inverter power losses. Performance of the proposed modulation technique is evaluated in MATLAB/Simulink environment and tested with a reduced scale prototype test platform. Both simulation and experimental results show the effectiveness of the proposed modulation technique.

Recent developments in multilevel inverters have provided impetus for their applications in the medium voltage renewable energy generation processes. This paper proposes an advanced pulse width modulation technique for a modular multilevel cascaded (MMC) inverter based grid integrated solar photovoltaic (PV) system. It offers lower total harmonic distortion (THD) and power losses compared to the existing modulation techniques. This paper shows the design and performance evaluation of the proposed technique using a 3-phase 5-level MMC inverter-based grid connected PV system. The proposed PWM technique offers 12.49% (without filter) and 0.96% (with filter) output line voltage THDs. It also offers 4.64% output current THD, which complies with the IEEE-519 standard for grid integration. Besides THD reduction, it also reduces the switching and conduction power losses of the MMC inverter. Lower losses may help to keep device temperature low, which is essential for power converters used in superconducting magnetic energy storage (SMES) systems. The simulation is performed in MATLAB/Simulink and the proposed technique is experimentally validated with a laboratory test platform.

The use of different control techniques has become very popular for controlling the performance of grid-connected photovoltaic (PV) systems. Although the proportional-integral (PI) control technique is very popular, there are some difficulties such as less stability, slow dynamic response, low reference tracking capability, and lower output power quality in solar PV applications. In this paper, a robust, fast, and dynamic proportional-integral resonance controller with a harmonic and lead compensator (PIR + HC + LC) is proposed to control the current of a 15-level neutral-point-clamped (NPC) multilevel inverter. The proposed controlled is basically a proportional-integral resonance (PIR) controller with the feedback of a harmonic compensator and a lead compensator. The performance of the proposed controller is analyzed in a MATLAB/Simulink environment. The simulation result represents admirable performance in terms of stability, sudden load change response, fault handling capability, reference tracking capability, and total harmonic distortion (THD) than those of the existing controllers. The responses of the inverter and grid outlets under different conditions are also analyzed. The harmonic compensator decreases the lower order harmonics of grid voltage and current, and the lead compensator provides the phase lead. It is expected that the proposed controller is a dynamic aspirant in the grid-connected PV system.