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One of the key components in photovoltaic (PV) electrical systems is the inverter. It is the unit that converters the DC power generated from the solar panels or the batteries to an AC power that can supply the electrical home appliances. The issues associated with the inverter are power quality and harmonics. This paper introduces a controller design for a single phase full bridge inverter for an off-grid PV electrical system which supplies a typical home or an office. For a pure sinewave inverter, a sinewave pulse-width modulation (SPWM) scheme is used. This puts the switching harmonics far away from the fundamental 50Hz component, which eases the filtering process by a simple low pass filter (LPF). As a result, a sinusoidal AC voltage waveform is obtained. Then, a step up voltage transformer is used to step up the voltage to 220V. As the AC load increases, the drop voltage on the LPF and the transformer primary increases significantly. This causes the secondary voltage of the transformer to drop drastically bellow 220V. To solve this issue, a cascaded voltage and current control loops are designed to control the transformer primary voltage at exactly 12V so that the secondary voltage is held always at 220V. The inverter circuit with the closed-loop control is simulated fully using Power Simulation (PSIM) software. Then, the inverter circuit is built and tested experimentally in the laboratory using only the open-loop control, and this is due to the lake of LEM voltage and current sensors in the laboratory.

This paper proposes the joint electro-magnetic and electro-thermal design optimization of a three-phase two-level voltage-source inverter, referring to the specific operational conditions of wind power conversion applications. The reference power level is 12 kW and the devices have a nominal voltage rating of 1.2 kV, typical values of small-scale wind turbines. Novel silicon carbide (SiC) devices are used to enable higher switching frequencies and operational temperatures, yielding in turn higher power density, without penalty on efficiency. Specifically, with relevance to commercial products, the paper focuses on the salient features of SiC and discusses their impact on system performance, elaborating on the associated bespoke design needs to yield optimum results in terms of inverter performance and power density, both volumetric and gravimetric. The study is of relevance primarily to on-ground systems, but also includes novel insight and results of straightforward spin-off transfer to a number of transport applications, including upcoming hybrid and fully electric naval and avionic applications.

This paper jointly investigates the switching performance and the short-circuit (S.C) turn off behavior of a novel half-bridge (2in1) IGBT power module concept with the low stray inductance (Lσ), which has been available in the market since 2015. Since this package was designed for improving the performance of Si-based switches and is a pioneering solution for designing WBG switches through reducing the Lσ of the switch itself, investigations of S.C are an important task for both researchers and designers. The performance of a Half-bridge (2in1) Silicon N-channel IGBT has been examined with different temperatures, switching transients and testing under S.C conditions, where the extracted results offer a clear overview of S.C of Half-bridge (2in1) package and trade-offs between switch losses and short-circuit safe operating area (SCSOA), and finally prevention of false turn-on after short-circuiting due to Lσ.

This paper proposes the optimised control and filter design of a 12 kW 3-phase 2-level wind inverter specifically taking into account the intermittent nature of the input power. In particular, the applied control scheme aims at optimising the low-load efficiency, which corresponds to the most frequent operational condition in time, by varying the switching frequency. Specifically, a silicon carbide (SiC) converter is addressed, which operates at relatively high frequency, thus enabling a significant reduction of the filter elements. So, the output filter design also needs to be optimised to ensure that the inverter electro-magnetic performance and the size reduction enabled by SiC are kept. That is achieved by designing a variable inductor based on soft saturation core material.

Taking full advantage of the superior characteristics of SiC Power MOSFETs in the application requires the development of bespoke packaging solutions. Their design needs to thoroughly encompass electromagnetic and electro-thermal aspects to yield major system-level benefits. New design approaches are needed in particular for parallel multi-chip structures at higher voltage ratings. With the aim of enabling full exploitation of the disruptive potential of SiC technology, this paper proposes a review of learnings made in the development of SiC bespoke power modules, focusing in particular on module designs compatible with the most widely established manufacturing, converter assembly and thermal management solutions for large volume applications.