多电平逆变器并网功率因数双重校正技术

Dual-correction Technology of Grid-connection Power Factor for Multi-level Inverter

针对电网电压相位跟踪、直接功率控制等逆变器并网控制技术,存在实时性差、参考电流不准确,功率因数低,总谐波畸变率(THD)高等缺点。提出了一种多电平逆变器并网功率因数双重校正技术,即通过逆变器输出侧电压和电流的相位差(即功率因数自校正)与逆变器输出侧电流和电网电压之间的相位差(即功率因数他校正),双重校正来实现逆变器的单位功率因数并网。用直接相位比较法测量相位差,并采用易于数字实现的空间矢量调制(SVPWM)算法。通过MATLAB/Simulink仿真,验证了控制方法的有效性。

In view of such disadvantages as poor real-time performance,inaccurate reference current,low power factor and high THD with grid voltage phase tracking,direct power control and other inverter grid-connection technologies,this paper presents a dual-correction strategy for the grid-connection power factor of the multilevel inverter,namely,dual correction （self-correction of power factor by means of phase difference between the voltage and current at the inverter output side,and correction of power factor by means of phase difference between the current at the inverter output side and the grid voltage）is used to realize grid connection through the unit power factor of the inverter.The phase difference is measured through direct phase comparison and easily digitalized SVPWM is applied.The effectiveness of this control method is verified through MATLAB/Simulink emulation.