A synchronous control method based on power balance is proposed to solve the problem that the input current THD of power factor correction can be greatly affected by phase unbalance, harmonics, offset, notching and so on. Furthermore, the feedforward control of load current is added to restrain the disturbance of both grid voltage and load, which improves the dynamic performance of system. On the basis of analyzing the mathematical model of three-phase three-level rectifier, a digital compensator for neutral point potential control is designed to suppress voltage unbalance of the capacitors. Simultaneously the amplitude regulation of the compensator is optimized using particle swarm optimization algorithm, which reduces the effect of neutral point potential adjustment on current THD. The control method is verified by the experimens on a prototype of 2.4kW, of which the THD is less than 5% when fully loaded, and the deviation of neutral point potential is less than 5V.%针对PFC输入电流的THD受电网不平衡、谐波、偏移等畸变情况影响较大的问题,提出了基于能量平衡的同步控制方法,同时引入负载电流的前馈控制,以抑制电网波动和负载扰动,提高系统的动态性能.分析了三相三电平整流器的数学模型,设计了一个中点电压控制数字补偿器,以抑制上下电容电压不平衡引起的中点电压波动,同时利用粒子群优化算法对中点电压平衡控制器的限幅值进行了优化设计,降低了中点电压调节对输入电流THD的影响.在所搭建的2.4kW的实验样机上,验证了控制方法的有效性,满载条件下输入电流THD＜5%,中性点电压偏差小于5V.
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