风力发电的MPPT快速响应控制方法

为了提高风力发电的能量转换效率，根据风车的空气动力特性，要用到最大功率点追踪(Maximum Power Point Tracking,MPPT)控制方法。作者开发了一种新的MPPT控制方法，和以往的MPPT控制方法相比，主要不同之处是：(1)追踪步长根据风速的变化而变化，即变扰动MPPT控制方式；(2)为了消除逆变器死区所造成的风车功率波动影响，MPPT控制周期和发电机的转速是同步的；(3)电磁转矩对风车转速实行完全控制，即在适当的时候，给风车提供能量使其加速，使风车转速能跟踪快速变化的风速；(4)在MPPT的输出端使用低通滤波器来平滑风车转速控制的指令值。实验结果表明，本方法可以跟踪0．2Hz快速变化的风速，和传统的MPPT控制方法相比，当风速快速变动时，可以显著增加发电量，从而提高了风力发电的效率。

A FAST RESPONSE MPPT CONTROL METHOD FOR WIND GENERATION

According to the aero-dynamical characteristic of the wind turbine, a maximum power point tracking (MPPT) is necessary to get high efficiency for wind power conversion. A new MPPT control scheme has been developed in this paper. The main differences between the method used in the proposed MPPT system and other techniques used in the past are as follows: (1) The tracking step is variable according to the variation of wind speed; (2) In order to avoid the dead time effect of the inverter the MPPT control is synchronized to the rotating speed of the generator; (3) The rotating speed of wind turbine is completely controlled, which means that the energy is fed to the wind turbine to 'help' it speedup when the wind speed changes rapidly and the rotating speed of wind turbine is low; (4) A low pass filter is used at the output of the MPPT controller to smooth the rotating speed reference. The resulting system has high-efficiency, fast and stable tracking speed. The experimental results showed that it can track as fast as 0.2Hz variation of wind speed and increases the efficiency of wind power conversion compared to the traditional MPPT control method especially when the wind speed changes rapidly.