Research on Predictive Control Strategy for Variable Speed Constant Frequency Hydroelectric Power Generation

For traditional hydropower stations, the generator speed is stabilized at a constant in order to maintain consistency with the grid frequency, which can cause problems such as reduced operational efficiency for the hydropower station. This constant speed operation can bring about problems such as reduced operational efficiency. Moreover, the control method used in traditional variable speed constant frequency hydroelectric power generation is proportional integral (PI) control, which has poor effectiveness in controlling complex processes with nonlinearity, time-varying, parameter and structural uncertainty. Therefore, model predictive control (MPC) and maximum power point tracking (MPPT) strategies were proposed. Based on the working principle of permanent magnet synchronous hydroelectric power generation, a predictive control simulation model was established, and a crowbar circuit was introduced to ensure energy stability during low voltage ride through, maintain DC bus voltage, and ensure stable operation of the hydroelectric unit under MPC control. The results showed that the MPC can effectively cope with the low voltage ride through process of the hydroelectric unit and improve its fault ride through ability.