基于有功功率控制的液压型风力发电机组最佳功率追踪策略关键问题研究

Research on the Key Problems of MPPT Strategy Based on the Active Power Control of Hydraulic Wind Turbine

液压型风力发电机组采用定量泵-变量马达闭式系统作为风机主传动系统,采用同步发电机直接并网发电,区别于传统齿轮或直驱型风机,需要对其最佳功率追踪策略进行深入研究。介绍液压型风机能量传递过程,最佳功率追踪控制需解决的关键问题,研究基于有功功率控制的最佳功率追踪原理。分析风力机功率传输特性,提出功率追踪分段控制策略。分析液压系统存在的非线性问题,利用小信号线性化方法结合变增益PID控制,解决系统非线性带来的功率响应不一致问题。最后利用转速控制环节对功率控制环节优化,使系统在功率追踪过程中系统更加平稳。在30k VA半物理仿真实验平台上验证变增益PID控制下系统功率一致响应,以及按最佳叶尖速比给定的最佳功率进行的最佳功率追踪策略。

The closed hydraulic system, fix displacement pump-variable displacement motor, is used as the main drive system in wind energy conversion system, synchronous generator connected to the motor is connected to the grid directly, which is different from the traditional gear or direct drive wind turbine, the optimal power tracking strategy as a result needs study. The energy flow and maximum power point tracking strategy based on active power control in hydraulic type wind turbine are introduced, and the key problem is proposed. the power transmission characteristics of wind turbine is analyzed, small signal linearization method combined with variable gain PID are used to solve the power response inconsistent problems that come from system nonlinearity, and the power control strategy is optimized by speed control to insure the system stability. Finally the power response and the maximum power point tracking strategy is verified in the 30kVA semi physical simulation platform.