The actual duty cycle of a single-stage Buck converter is affected by the switching speed and dead time, so it is difficult to meet the wide range of voltage regulation applications. On this basis, a multilevel cascade Buck topology is adopted, and an output voltage cooperative control strategy for multilevel cascade converters is proposed. This control strategy takes into account the operation efficiency, and it adopts a hybrid modulation method combining pulse width modulation and frequency conversion modulation, thus realizing the output voltage control switching at all levels of the converter and covering the full range of output voltage. A switching loss model is established, and the efficiency optimization under hybrid modulation is analyzed. Finally, a simulation model was established to verify the correctness of the modulation and control design, and an 8 kW two-stage prototype with 50–75 V input and 1–40 V/200 A output was built to verify the feasibility of the proposed control strategy.
| 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 |