A Simplified Space-Vector Modulation Algorithm for Four-Leg NPC Converters

Abstract

Abstract-To interface generation sources and loads to fourwire distribution networks is important to use power converters and modulation methods which provide high performance, flexibility and reliability. To achieve these goals, this paper proposes a simple and efficient Space Vector Modulation (SVM) algorithm in αβγ coordinates for Neutral Point Clamped (NPC) converters. The proposed SVM method reduces a three-dimensional (αβγ) search of the modulating vectors into a simple two-dimensional (αβ) problem. Moreover, the algorithm provides full utilisation of the dc-link voltage, full utilisation of the redundant vectors and it can be applied to any other four-leg converter topology. The proposed SVM has been successfully validated using a 6kW three-level four-leg NPC converter, achieving control over the voltages of the dc-link capacitors and simple definition of switching pattern for shaping frequency spectrum.

A Design Methodology of Multiresonant Controllers for High Performance 400 Hz Ground Power Units

“…Fig. 11 shows the reference voltage generated by the controller, which is then synthesized by the 3D-SVM [24], [25]. Clearly, the reference voltage is far from an ideal sinusoidal shape.…”

“…A single-loop resonant controller controls the output voltage of the GPU, compensating third, fifth, seventh, ninth and eleventh harmonics. A three-dimensional SVM algorithm in αβγ coordinates is used to synthesize the output voltages [24]. Furthermore, using the redundant vectors of the four-leg NPC and output current measurements, a PI controller is used to balance the voltage on the dc-link capacitors.…”

“…To generate the voltage demanded by the multiple resonant controllers, the three-dimensional SVM presented in [24], [25] has been used. Fig.…”

Control of Modular Multilevel Converters Using an Overlapping Multihexagon Space Vector Modulation Scheme

“…The Space Vector Modulation (SVM) scheme offers attractive features and both two and three-dimensional versions are widely known and applied [28][29][30][31][32][33][34][35]. However, for an MMCC having many voltage levels per phase, using conventional SVM technique, the number of switching states escalates, and on-line switching vector selection and duty cycle calculation become complicated [36][37][38].…”

“…Calculation of selected vector duty cycle and selection of switching states can then be carried out as in a two level inverter. Extension of this approach to five-level space vector plane has also been attempted, and meanwhile optimal switching sequence for achieving good harmonic performance and capacitor voltage balance has been proposed [31][32][33][34]. The main problem with the space vector plane division approach lies in the use of lookup tables for generating the gate pulses for the switching devices.…”