It is well known and widely accepted that the voltage source inverter (VSI) now dominates the world of electrical drives. Its success is probably due to its simplicity, high efficiency, and the widespread availability of VSs. This popularity has, in turn, influenced the evolution of the semiconductor industry, which has focused in recent years on devices tailored for VSIs. Thus, products such as depletion devices (normally off) and those without reverse voltage blocking have been widely marketed and used.

This paper analyzes the performance of a grid-tied, wide power range, transformerless, modified three-phase current-source inverter (CSI), named CSI7. The CSI7 topology is here analyzed along with a suitable space vector modulation strategy able to attenuate the excitation of the output CL filter. The theoretical analysis and simple analytic expressions highlighted the performance and limitations of the topology when employed as a single-stage photovoltaic (PV) inverter, with a particular emphasis on injected grid current distortion and ground leakage current values. The inverter wide input range allows interfacing PV strings of different module count with a simple closed-loop control. The principle of operation and control is described; the viability of the CSI7 topology was assessed with simulations and extensive experiments on a full-size laboratory prototype.

The Current Source Inverter (CSI) is a power electronics topology that allows for the realization of variable speed drives (VSD). Compared to the most common Voltage Source Inverter (VSI), which can be directly connected to a voltage source, the CSI needs a pre-stage to generate a constant current bus. This paper therefore seeks to challenge this 'accepted' consideration that a CSI always needs this pre-circuit and seeks to remove this circuit by proposing an innovative $i_{dc}$ Current Control scheme. The proposed scheme is applied to a single stage motor drive driven by a CSI converter. It is shown how implementing this control scheme removes the need for the front-end stage, thus removing an unnecessary converter and optimizing the efficiency at the same time. The CSI state-space equations are presented and the developed models are verified using simulations. Stability analysis of small - signal model is considered through Nyquist criterion with the robustness in presence of variations of the most important system parameters.\\ Experimental results driving a Permanent Magnet Synchronous Machine (PMSM) are shown confirming the validity of the proposed control, potentially paving the way to a larger adoption of the CSI topologies for motor drive applications.

Aircraft electrification has been a major trend in aviation industry for past 20 years. Given the increasing electrical power requirement for future more electric aircraft and hybrid electric aircraft, research efforts has been ongoing in high power electrical conversion for air-borne systems. Safety critical nature of aviation systems places reliability of aerospace power converters as a critical design concern. In this paper, power electronic system reliability is studied with emphasis on lifetime limiting factors of critical sub components. Reliability of voltage source power converters at different system voltage levels are modelled for a starter generator drive converter. A key observation is that Si IGBT devices are sufficient with respect to reliability requirements in low and medium voltage systems (up to 540V). At higher system voltages (above 540V), multi level topologies are necessary for designing with Si IGBTs. In constant power profile drive, system reliability is minimally affected by wear-out failure of film capacitors in converter DC links. In multi level topologies without enhanced voltage derating, system reliability is dominated by cosmic ray induced random failures. Simulation results demonstrate that at high system voltages (810V), 2L topology with SiC mosfets outperform Si IGBT based 3L topology with respect to reliability.