一种改进型MPPT控制的光伏发电及其并网逆变器的研究

Research on an improved MPPT control for photovoltaic power generation and grid connected inverter

光伏电池输出特性曲线方程是光伏发电理论研究的基础,首先建立光伏电池工程用数学模型,然后为了能够更有效地提高光伏发电系统的最大输出功率,在传统电导增量法的基础上提出了一种改进型的MPPT算法,经过验证此方法不仅能够有效提高跟踪速度和精度,而且可以较好的抑制系统在最大功率处的波动.并网的光伏发电系统,由公网系统提供电压支撑,所以可以采用P-Q控制方式的逆变器使其输出恒定的有功和无功功率.整个控制系统包括3个环节,分别是MPPT环、并网逆变器的电压外环和电流内环,MPPT环可与电压外环和电流内环相互独立,即升压电路与逆变电路分别由2个控制器独立完成.

The output characteristic curve equation ofphotovoltaic cells is the basis of the theoretical research of photo- voltaic power generation. So we firstly establish the mathematical model ofphotovoltaic cell engineering, and then in order to improve the maximum output power ofphotovoltaic power generation system effectively in the established model, the MPPT algorithm improved based on the traditional cond0ctance increment method is proposed, which can not only improve the tracking speed and precision, but also can suppress the fluctuation of the system at the maximum power point. Grid connected photovoltaic power generation system, the public network systems to provide voltage support so that it can be used in the P-Q control mode of the inverter to make its output constant active and reactive power. The whole control system consists of three parts, namely, the MPPT loop, the voltage outer loop and the current inner loop of the grid connected inverter, The MPPT loop is independent of the voltage outer loop and current inner loop, that is, the boost circuit and the inverter circuit are completed by two controllers.