SVPWM strategy of dual inverters and zero-sequence voltage suppression method

The dual inverter has the same distribution of space voltage vectors with three-level inverters, and the utilization of DC link voltage is improved. Therefore, the dual inverter is widely applied in open-end winding motor drive systems. Based on the analysis of principle of the dual inverter, modulation strategies were researched and a dual inverter space vector pulse width modulation (SVPWM) strategy in maximum voltage range was proposed. In the proposed strategy, the plane can be divided into six sectors and then the voltage vector reference can be divided into two parts. One part is equivalent to a special switching state clamped by one inverter, and the other part is modulated by the other inverter in the six sub-sectors divided further in each sector. In order to suppress the zero-sequence voltage, a factor was introduced to redistribute zero voltage vectors during the synthesis. The zero-sequence voltage produced by basic voltage vectors can be counteracted by that of the redistributed zero voltage vectors. Simulation model and experimental bench of the vector-controlled open-end winding permanent magnet synchronous motor drive system were built, and the simulation results as well as experimental ones validate the proposed method.