Aimed at the problems of unbalanced capacitor neutral-point voltage and high common-mode voltage in a permanent magnet synchronous motor drive system powered by a T-type three-level inverter, a model predictive instantaneous torque control (MPITC) strategy based on finite voltage vector set optimization is proposed. First, in view of the influence of voltage vectors on the neutral-point voltage, only zero, small and large vectors are selected to participate in MPITC. Second, according to the relationship between the switching states and common-mode voltage, it is confirmed that 13 low common-mode voltage vectors participate in the control. To improve the operation performance of the motor, the long vector synthetic virtual voltage vector is used to replace the medium vector to participate in the model predictive control. Finally, according to the neutral-point potential and the motor current direction, the voltage vector which is favorable for maintaining the neutral-point voltage balance is selected from 19 voltage vectors as the preselected vector set. Experimental results show that the proposed control strategy can effectively reduce the electromagnetic torque, flux linkage pulsation and common-mode voltage amplitude, and the neutral-point voltage achieves balanced control.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |