Research Article
Modified Quasi-Steady State Model of DC System for Transient Stability Simulation under Asymmetric Faults
Table 2
The commutation process and the corresponding DC voltage instantaneous value for the single bridge inverter within one cycle.
| Trigger pulse | Time period | Upper bridge valve state | Lower bridge valve state | Commutation state | DC voltage waveform | Corresponding relationship | DC voltage calculation |
| | ~ | Valve 3 commutes to 5 | Valve 4 conducting | to | | p-c, q-b, r-a | | ~ | Valve 5 conducting | Valve 4 conducting | — | | p-c, r-a | |
| | ~ | Valve 5 conducting | Valve 4 commutes to 6 | to | | p-b, q-a, r-c | | ~ | Valve 5 conducting | Valve 6 conducting | — | | p-b, r-c | |
| | ~ | Valve 5 commutes to 1 | Valve 6 conducting | to | | p-a, q-c, r-b | | ~ | Valve 1 conducting | Valve 6 conducting | — | | p-a, r-b | |
| | ~ | Valve 1 conducting | Valve 6 commutes to 2 | to | | p-c, q-b, r-a | | ~ | Valve 1 conducting | Valve 2 conducting | — | | p-c, r-a | |
| | ~ | Valve 1 commutes to 3 | Valve 2 conducting | to | | p-b, q-a, r-c | | ~ | Valve 3 conducting | Valve 2 conducting | — | | p-b, r-c | |
| | ~ | Valve 3 conducting | Valve 2 commutes to 4 | to | | p-a, q-c, r-b | | ~ | Valve 3 conducting | Valve 4 conducting | — | | p-a, r-b | |
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The expression of “” means a time period from time instant “” to the time instant “”.
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