Figure 1.
(a) DOESWIM supplied by two cascaded two-level inverters. (b) Structure of the two cascaded two-level inverters.
Figure 2.
Principle of the phase-disposition PWM for two cascaded inverters. PWM, pulse width modulation.
Figure 3.
Variation of the speed, the two-stator currents, and the torques.
Figure 4.
Variation of the pole’s voltage converters and machine.
Table 1.
Comparative analysis of the proposed architectures.
| OEWIM Two-level inverter | OEWIM Two cascaded Two-level inverters | DOESWIM Two-level inverter | DOESWIM Two cascaded Two-level inverters | |
|---|---|---|---|---|
| Number of voltage level | 3 | 5 | 3 | 5 |
| DC voltage value | E/2 | E/4 | E/2 | E/4 |
| Sizing of inverter power | P/2 | Inverter A11: P/2 | P/4 | Inverter A11: P/2 |
| Inverter A12: P/4 | Inverter A12: P/4 | |||
| Current I (A) | I | I | I/2 | I/2 |
| THD voltage (%) | 44.27 | 24.99 | 43.86 | 26.77 |
| THD current (%) | 0.52 | 0.39 | 0.66 | 0.41 |
| ∆Tem (%) | 1.26 | 0.88 | 1.66 | 0.83 |
Figure 5.
Feeding of DOESWIM by four converters for the first configuration.
Figure 6.
Variation of the two-stator currents, speed, and torques for the first configuration.
Figure 7.
Variation of the phase-to-phase voltage inverters and machine for the first configuration.
Figure 8.
(a) Feeding of the DOESWIM by four converters for the second configuration. (b) Reconfiguration of the converters A2 and B2 for the second configuration.
Figure 9.
Variation of the phase-to-phase voltage inverters and machine for the second configuration.
Figure 10.
Variation of the two-stator currents, speed, and torque for the second configuration.
Figure 11.
(a) Feeding of the DOESWIM by four converters for the third configuration. (b) Reconfiguration of the converters A2 and B2 for the third configuration.
Figure 12.
Variation of the phase-to-phase voltage inverters and machine for the third configuration.
Figure 13.
Variation of the two-stator currents, speed, and torque for the third configuration.
Figure 14.
Feeding of the DOESWIM by four converters for the fourth configuration.
Figure 15.
Operational mode of the double star asynchronous machine powered by two converters for the fourth configuration.
Figure 16.
Variation of the phase-to-phase voltage inverters and machine for the fourth configuration.
Figure 17.
Variation of the two-stator currents, speed, and torque for the fourth configuration.
Table 2.
Quantitative performance comparison.
| Nominal Mode | Fault 1 | Fault 2 | Fault 3 | Fault 4 | |
|---|---|---|---|---|---|
| THD current (%) | 0.4 | 2.02 | 21.5 | 20.6 | 32 |
| Torque ripple (%) | 0.83 | 1.3 | 1.2 | 0.9 | 1.2 |
| Peak current (A) | 76 | 76 | 70 | 72 | 76 |
| THD voltage (%) | 26.7 | 40 | 46.8 | 42.2 | 60 |
Figure 18.
FFT spectra of the output voltage for the normal mode.
Figure 19.
FFT spectra of the output voltage for the different fault configurations.