| Abstract |
This paper proposes new modulation strategy in order to balance neutral-point voltage in the three-level Voltage Source Inverter (VSI). In the proposed method, not only initial neutral-point voltages and wanted voltage vector but also resulted current is used to detect and apply appropriate space vectors. In this method, all space vectors can be categorized into two dynamic groups which are P-Type and N-Type vectors. For each dynamic category, containing vectors are selected based on resulted current vector. This method slightly injects high order harmonics which lead to enhance voltage THD, due to using small and medium space vectors. Respecting dynamic categorizing, the proposed method has strong capability to rapidly balance neutral-point voltage, with regardless ripple for all modulation index ranges and balanced/unbalanced loads. Simulation results verify the validity and capability of the modulation strategy, also the proposed method is easy to implement without adding any extra hardware and expenses. |
