Multilevel Inverter for Hybrid Fuel Cell/PV Energy Conversion System

Power converters assume a significant part in fuel cell power generation systems and solar power conversion systems which are an alternative to fossil fuel production systems. There is therefore a demand for high quality power conditioning used in PEMFC systems and photovoltaic panels. This chapter proposes a hybrid electric power (FC/PV) production strategy with the use of converter topology as the power interface and also introduces a three-level inverter topology for different operating levels. The converter increases the input voltage to the rated voltage and turns into a DC bus; the multi-level inverter converts the voltage to AC and supplies AC loads. This chapter develops a hybrid electric power generation strategy, which can produce output with positive and zero sequences. Integrating the three-stage inverter into the hybrid renewable energy (FC/PV) production system allows for near sinusoidal current with low THD. The topology of hybrid energy production using the multi-level converter is tested on Matlab.

Current Protection Applicability Analysis of Flexible DC Power Supply Network

In the flexible AC/DC distribution system supplying passive network, when the modular multi-level converter (MMC) inverter AC line fault occurs, the MMC short-circuit current amplitude is greatly affected by the control strategy, which may affect the operation performance of three-stage current protection. In view of this, a flexible AC/DC distribution network system supplying power to the passive network is built on the RTDS platform, and then the AC fault traverse strategy is designed in the MMC controller. Based on the thinking of coordinated control and protection of the fault through the strategy into two cases with no input to higher current protections performance simulation contrast, the simulation results show that asymmetric fault occurred when MMC inverter AC line, under the effect of communication failure through the strategy, the current main protection I, II period of refusing action, only by this line nearly backup protection current section III delay removal of fault. The three-stage current protection based on the fault current characteristics of pure AC system has poor action performance and is no longer suitable for the AC line of MMC inverter station.

Five Level Flying-Capacitor Multilevel Converter Using Dynamic Voltage Restorer (DVR)

This paper deals with dynamic voltage restorer (DVR) controlled by a five-level flying-capacitor multi level converter. To decrease the power-quality disturbances in distribution system, such as voltage imbalances, harmonic voltages, and voltage sags. The organisation of this paper has been divided into three parts; the first one eliminates the modulation high-frequency harmonics using filter increase the transient response. The second one deal with the load voltage; and the third is flying capacitors charged with balanced voltages. The MATLAB simulation results effectively for five level flying capacitor multilevel converters charged with balanced voltage regulation.

Research on Topology and Control System of High Power Grid Simulator

Grid simulator can simulate the output of various types of power grid failure to test wind power grid-side equipment, in the design of high-power grid simulator, due to the switching frequency restrictions, will affect the control bandwidth, resulting in the power grid simulator system performance decline. Therefore, the modular multi-level converter (MMC) with higher equivalent switching frequency is used on the inverter side of the grid simulator, and the bridge arm circulation suppression strategy based on the second-order generalized integrator (SOGI) and vector scale integral (VPI) resonant controller is proposed for the internal bridge arm circulation of the converter. Finally, based on RT-LAB, the network simulator controller hardware in the ring (CHIL) experimental platform is built and experimented, the experimental results show that the design of high-power power grid simulator system can simulate the output to obtain the required grid failure.

Research on dynamic current sharing method of parallel connected IGBT modules for NPC three level converters

The parallel connection of IGBTs has been being applied in high power neutral point clamped (NPC) three level converters. This paper investigates the impact of gate parameters (gate resistor and capacitance) on dynamic current imbalance of parallel connected IGBT for NPC three level converter. A gate parameters calculation method is proposed in the paper, and the delay time and collector current difference can be analysed quantitatively. Experimental results have shown the effectiveness of the method.