In off-grid photovoltaic storage microgrids, the DC-side bus voltage amplitude is easily affected by the fluctuation of photovoltaic (PV) output power and load power, the system may experience DC bus voltage oscillation and long voltage recovery time under the traditional control strategies. In order to improve the dynamic stability of bus voltage, a fuzzy-proportional integral (PI) control method based on nonlinear disturbance observer (NDO) power feedforward is proposed. Firstly, the system state equation in storage discharge mode is established, and the disturbance observation link is designed to observe the disturbance power of the PV and load in real time and add it to the current inner loop as a feedforward quantity after correction. Then, a fuzzy-PI controller based on bus voltage deviation is designed to improve the structure of voltage outer loop, and the design process of disturbance observer and controller is given. Finally, the simulation and experimental results verify that the strategy can have good dynamic stability of DC bus voltage under load impact.
| 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 |