一种适用于小功率可再生能源的单相高频双Buck全桥并网逆变器

摘要

A single-phase high frequency dual-Buck full-bridge inverter for small-scale renewable source application is proposed in this paper.Based on the entire SiC power switches,the proposed inverter can operate in a high frequency at 100 kHz,and thus both the inductor volume and the ripple of the grid-connected current are reduced.This paper also analyzes the control strategy of the inverter,where a voltage-current dual loop controller is employed.In the current loop,a three-pole-three-zero (3P3Z) compensator is applied to make sure that the grid-connected current can fast track the current reference generated by the voltage loop.A simple linearization algorithm is also adopted to calculate the controlling duty cycle,to achieve high frequency operation.Besides producing the current reference,the voltage loop employs a two-pole-two-zero (2P2Z) compensator to stabilize the bus voltage at the voltage reference,so that the inverter can delivery power to the grid and regulate bus voltage simultaneously.Moreover,a second-order generalized integrator software phase lock loop (SOGI-SPLL) is used to generate the phase signal,which has the same phase with grid voltage.At last,prototype experiment has verified the theoretical analyses.%提出一种适合小功率可再生能源并网发电应用的单相高频双Buck全桥并网逆变器.基于全碳化硅(SiC)功率器件,逆变器工作频率可达100kHz,有效减小了电感体积,同时使并网电流纹波降低.进一步分析逆变器的控制策略:采用电压电流双环控制,在电流环利用一种三极点三零点(3P3Z)控制器使得受控并网电流快速跟踪电压环产生的电流给定,并采用一种简单线性化算法快速产生控制占空比信号,实现高频变换;电压环采用双极点双零点(2P2Z)控制器,在产生电流内环给定幅值的同时,控制输入侧直流母线电压稳定在电压给定值,使得逆变器能够向电网传输能量的同时维持母线电压恒定;逆变器采用一种二阶广义积分软件锁相环(SOGISPLL)产生与电网电压相位相同的相位信号.最后,通过实验样机对逆变器理论分析的有效性进行了验证.