超级电容接口双向DC-DC变换器的电压快恢复控制策略

Fast Voltage Recovery Control Strategy for Supercapacitor Interfacing Bidirectional DC-DC Converter

直流微网中控制母线电压稳定是核心问题,在母线受到不同时间尺度的功率扰动时显得尤为重要。针对直流母线瞬时功率不平衡问题,结合超级电容高功率密度特性,将电容电荷平衡控制思想引入超级电容接口双向DC-DC变换器,以实现母线电压在负载大扰动下的快速恢复。在现有单向电流DC-DC变换器的电容电荷平衡控制基础上,将间接预测电容电流变化规律的思路进行扩展和优化,得出一般的节点电流替代法及相应的控制律,达到快速控制双向DC-DC变换器的目的。给出了电容电荷平衡复合控制策略的具体实现过程,并利用平均电流模式控制和滞环电流限幅环节实现对接口变换器的双端稳定控制。最后通过仿真和样机实验验证了所提复合控制策略的有效性。

Control of bus voltage stability in DC microgrid is a key issue,which is particularly important when the DC bus is disturbed at different time scales.In order to solve the problem of instantaneous power imbalance of the DC bus,the idea of capacitor charge balance control(CBC)was introduced to supercapacitor interfacing bidirectional DC-DC converter to realize fast recovery of bus voltage with high power density of the supercapacitor.Based on existing CBC for unidirectional current DC-DC converter,the idea of indirectly predicting the change of capacitor current was extended and optimized.Moreover,the general substitution method of node current was obtained and the corresponding control law was also derived to achieve the objective of fast control of bidirectional current.The detailed implementation of the hybrid control strategy based on CBC was given,and the average current mode control combined with hysteresis current limiter were used to realize stable control of the interfacing converter at both sides.Finally,simulation and prototype experiments verify the effectiveness of the proposed hybrid control strategy.