New Modulation Strategy for Five-Phase High-Frequency VSI Based on Sigma–Delta Modulators

This article proposes a new modulation strategy for a five-phase high-frequency voltage source inverter (VSI) based on sigma–delta (
$\Sigma \Delta$
) modulators. This modulation strategy of five-phase large–medium-zero vectors
$\Sigma \Delta$
(5P-LMZV-
$\Sigma \Delta$
) applies the same switching states as the two large and two medium space vector modulation (2L+2M SVM). Because
$\Sigma \Delta$
modulations are designed to operate at high switching frequencies, using wide-bandgap devices, therefore, improves the efficiency of the VSI, despite its operating at these high switching frequencies. We analyze the use of single-loop and double-loop
$\Sigma \Delta$
modulators (SL-5P-LMZV-
$\Sigma \Delta$
and DL-5P-LMZV-
$\Sigma \Delta$
, respectively), and additionally modify the proposed modulation strategy to use all the vectors in order to analyze the effects from applying small vectors. The proposed modulation techniques allow minimizing switching losses due to the reduced switching operations, mitigating low-order harmonics, decreasing the amplitude of high-frequency harmonics, and reducing common-mode voltage
dv/dt
transitions. We analyze the performance of the proposed modulation technique using MATLAB/Simulink and PLECS, and then compare it with 2L+2M SVM. Using a VSI with silicon carbide
mosfet
, we obtained our experimental results demonstrating these characteristics, by which we conclude that our proposed strategy is an improvement over 2L+2M SVM.