As a mainstream high-efficiency DC-DC converter, the LLC resonant converter faces an issue of a narrow voltage regulation range, and a hybrid modulation technique combining pulse frequency modulation (PFM) and phase shift modulation (PSM) can effectively broaden the voltage regulation range. However, a single proportional integral (PI) controller cannot adequately balance the system stability and responsiveness in the two operating modes. Aimed at this problem, a hybrid modulation adaptive control strategy for the LLC converter is proposed. First, a small-signal model of the LLC converter in PFM and PSM modulation modes is established using an extended describing function method. Then, a model correction algorithm is developed with an objective of unanimous rate of change of the model gain, so as to obtain a unified model of the LLC resonant converter. Furthermore, based on this unified model, adaptive PI controllers are designed considering input voltage and load current, thus realizing the stable performance and dynamic response of the converter across the entire load and input ranges. Finally, the effectiveness of the proposed adaptive control strategy was validated by the construction of a simulation model and an experimental platform.
| 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 |