对电机驱动系统前置双向Buck/Boost变换器后直流母线电压的波动抑制问题进行研究。分析功率前馈控制策略抑制母线电压波动能力较弱的原因。对双向Buck/Boost变换器提出一种母线电容能量外环、输出功率内环的直接功率控制策略,并将输出功率的变化趋势反映到双向Buck/Boost变换器的发波环节,进一步提高了变换器的动态响应特性。基于小信号模型分析上述两种控制策略的本质区别。小信号模型分析结果、仿真和实验结果都证实,提出的直接功率控制策略比功率前馈控制策略有更好的抑制母线电压波动的能力。
The DC bus voltage fluctuation suppression in the motor drive system with a bi-directional Buck/Boost converter was studied.The disadvantage that the power feed-forward control scheme cannot effectively suppress bus voltage fluctuation was analyzed.A novel direct power control scheme with bus capacitor energy outer control loop and output power inner control loop for the bi-directional Buck/Boost converter was presented.Moreover,in order to improve the dynamic response of converters,a feed-forward term which reflects the changing trends of output power was added on its duty cycle calculation node.The essential difference between the above two control schemes was compared.Results and simulations of the small-signal model analysis and experimental results show the direct power control scheme has good performance in voltage fluctuation suppression.