改进模型预测控制的双闭环优化控制策略

Double closed-loop optimal control strategy of improved model predictive control

混合储能系统(HESS)通过吸收和释放能量,在微电网功率波动时可有效维持母线电压稳定。HESS通常采用PI双闭环控制策略,但由于PI调节存在一定的滞后性,导致系统存在动态响应速度不佳的问题。改进模型预测控制(MPC)的双闭环优化控制方法,可以提高系统的响应速度。对外环电压与内环电流分别搭建预测模型构成双闭环结构,并在目标函数中对被控量的变化率加以限制来提高MPC算法的稳定性。仿真结果表明,与PI双闭环控制相比,电压恢复时间减少了56%,提高了系统动态响应速度,与MPC控制方法相比,调节时电压的超调量降低了32%,提高了系统稳定性。

Hybrid energy storage system(HESS)can effectively maintain the bus voltage stability when the power of microgrid fluctuates by absorbing and releasing power.HESS usually adopts PI double closed-loop control strategy,but due to certain lag in PI adjustment,the system has poor dynamic response speed.In this paper,an improved model predictive control(MPC)double loop optimization control method was proposed to improve the response speed of the system.The prediction models of the outer loop voltage and the inner loop current were constructed to form a double closed-loop structure,and the method of limiting the rate of change of the controlled quantity in the objective function improved the stability of the MPC algorithm.The simulation results show that compared with PI double closed-loop control,the voltage recovery time is reduced by 56%,the dynamic response speed of the system is improved,and the overshoot during adjustment is reduced by 32%compared with MPC control method,which improves the system stability.