Quarter-Wave Symmetric Space Vector PWM with Low Values of Frequency Modulation Index in Control of Three-Phase Multilevel Voltage Source Inverter

Common-Mode Voltage Elimination of Three-Phase Multilevel Voltage Source Inverter by Means of Quarter-Wave-Symmetric Space Vector PWM Approach

“…In addition, the linear range of the phase voltage amplitude modulation index is decreased 2 √ 3 times. Nevertheless, the voltage quality is quite acceptable in the m aY range of 1…3, and it can be improved in the values of IHF of specified order by m f value matching [10].…”

“…Like the baseline QWS-SVPWM algorithm, the new CMVE-SVPWM algorithm relies on the three-segment switching sequence scheme, producing the quarter-wavesymmetric output voltages' waveforms. The moving of the executed voltage space vector (EVSV) is non-returnable on each clock cycle interval and follows the same vector sequences as in [10], but the coordinates u * Cn , u * An are itself new and correspond to Fig. 4a.…”

“…In view of the simplicity of the operations in ( 7)-( 9), as well as of the f Cnexek (t kc ) and f Anexek (t kc ) values finding, the consideration of the full 360°range could be even more effective. One can obtain the whole data on f Xnexek (t kc ) in [10], replacing the As can be seen in the space vector diagram of the zero-common-mode-voltage space vectors for the seven-level inverter (Fig. 4a), the maximum relative magnitude of the RVSV and EVSV vectors U * max (the maximum phase voltage amplitude modulation index m aYmax ), which requires applying no unprogrammed vectors and employing no overmodulation strategy, is equal to 3.…”

“…The purpose of this paper is to offer a new, general and simple common-modevoltage-eliminating SVPWM algorithm for three-phase MLVSI of any arbitrary topology with any arbitrary number of generated equal voltage levels. It can be treated as some modification or customization of the before proposed author's quarter-wave-symmetric SVPWM (QWS-SVPWM) technique [10,11].…”

“…The u * Cn and u * An values are projected to the new oblique-angled 60°axes in a similar way as it had done in Fig.3afor the u * AB and u * BC values. The CMVE-SVPWM algorithm employs all the attributes and steps of the baseline QWS-SVPWM algorithm[10], just replacing the delta voltages with the relevant star voltages, namely u * AB with u * Cn , u * BC with u * An and u * CA with u * Bn . In particular, the coordinates and duty cycles of the modulating triangles' vectors are the integer and fractional parts of the samples u * Xnrefs of the reference star voltages and their inverse values, see Fig.4b("refs" in the subscripts are omitted in the figure).…”