Design, Optimization and Implementation of a High Frequency Link Multilevel Cascaded Inverter

This thesis presents a new concept of cascaded MLI (CMLI) device reduction by utilizing low and high frequency transformer link. Two CMLI topologies, symmetric and asymmetric are proposed. Compared with counterpart CMLI topologies available in the literatures, the proposed two inverter topologies in this thesis have the advantages of utilizing least number of electronic components without compromising overall performance particularly when a high number of levels is required in the output voltage waveform

Design and implementation of a novel three-phase cascaded half-bridge inverter

In this study, a new circuit topology of a three-phase half-bridge multilevel inverter (MLI) is proposed. The proposed MLI that consists of a cascaded half-bridge structure along with a modified full-bridge structure requires less number of dc-power supplies and power semiconductor devices, e.g. insulated gate bipolar transistors and diodes when compared with the existing MLI topologies, which significantly reduces the size and cost of the inverter. Two different structures: isolated and non-isolated dc-power supply-based three-phase half-bridge MLIs are investigated. A number of generalised methods are proposed to determine the magnitude of the input dc-power supplies that has a great impact on the number of levels of the output voltage waveform. To verify the feasibility of the proposed MLI topology, a scaled down laboratory prototype three-phase half-bridge MLI is developed and the experimental results are analysed and compared with the simulation results. Experimental and simulation results reveal the feasibility and excellent features of the proposed inverter system

Industrial IoT based condition monitoring for wind energy conversion system

Wind energy has been identified as the second dominating source in the world renewable energy generation after hydropower. Conversion and distribution of wind energy has brought technology revolution by developing the advanced wind energy conversion system (WECS) including multilevel inverters (MLIs). The conventional rectifier produces ripples in their output waveforms while the MLI suffers from voltage balancing issues across the DC-link capacitor. This paper proposes a simplified proportional integral (PI)-based space vector pulse width modulation (SVPWM) to minimize the output waveform ripples, resolve the voltage balancing issue and produce better-quality output waveforms. WECS experiences various types of faults particularly in the DC-link capacitor and switching devices of the power converter. These faults, if not detected and rectified at an early stage, may lead to catastrophic failures to the WECS and continuity of the power supply. This paper proposes a new algorithm embedded in the proposed PI-based SVPWM controller to identify the fault location in the power converter in real time. Since most wind power plants are located in remote areas or offshore, WECS condition monitoring needs to be developed over the internet of things (IoT) to ensure system reliability. In this paper, an industrial IoT algorithm with an associated hardware prototype is proposed to monitor the condition of WECS in the real-time environment. © 2015 CSEE

A Three-Phase Symmetrical DC-Link Multilevel Inverter with Reduced Number of DC Sources

We present a combination of fjord bathymetry and shallow seismic data from Kongsfjorden and Krossfjorden, Svalbard, to characterize and analyse change in the fjord coastal environment physiography and the glaciosedimentary processes since the Last Glacial Maximum. Swath bathymetry reveals a series of several styles of landform, frequently superimposed upon each other, permitting the reconstruction of the relative timings of deposition of each landform with the oldest successively overlain and cross-cut by younger landforms and erosional processes. Large transverse ridges interpreted as recessional moraines are overlain by streamlined lineations formed subglacially during a subsequent ice advance. A complex of recessional morainal ridges occurring within the central fjord are incised by glacial lineations and meltwater channels from younger glacial events

Industrial IoT based condition monitoring for wind energy conversion system

Wind energy has become a second dominating source in the world renewable energy generation. Conversion and distribution of the wind energy have brought technology revolution by developing advanced wind energy conversion system (WECS) including multilevel inverters (MLI). The conventional rectifier produces ripples in their output waveforms while MLI suffers from voltage balancing issue across dc-link capacitor. This paper proposes a simplified proportional integral (PI)-based space vector pulse width modulation (SVPWM) to minimize the output waveform ripples, resolve the voltage balancing issue and produce better-quality output waveforms. On the other hand, WECS experiences various types of faults particularly in the dc-link capacitor and switching devices of the power converter. These faults, if not detected and rectified at early stages, they may lead to catastrophic failures to the WECS and continuity of power supply. This paper proposes a new algorithm embedded into the proposed PI-based SVPWM controller to identify the fault location in the power converter in real time. Since most wind power plants are located in remote areas or offshore, WECS condition monitoring needs to be developed over the internet of things (IoT) to ensure system reliability. In this paper, an industrial IoT algorithm with associated hardware prototype is proposed to monitor the condition of WECS in real-time environment