基于非线性微分几何理论,提出了一种基于精确反馈线性化的定频PWM滑模变结构控制策略。应用脉冲波形积分法建立电感电流连续(CCM)开关变换器的仿射非线性系统模型;在满足精确反馈线性化条件下,采用状态反馈精确线性化方法,推导了非线性坐标变换矩阵和状态反馈表达式,实现了变换器的线性化。以线性化后的布鲁诺标准型为新被控对象.采用指数趋近律设计了滑模控制器。仿真结果表明:该方法不但比传统PI控制具有更好的稳态特性、更快的响应速度、更强的抗干扰能力,而且优于基于微分几何的最优控制策略。
According to the nonlinear differential geometry theory,a tixed-frequency-PWM sliding-mone variable- structure control based on precise feedback linearization is proposed for DC- DC switching converter. A nonlinear affine model of Buck converter working on CCM(Current Conduction Mode) is set up using the impulse integral modeling method. On the premise of precise feedback linearization,the state feedback linearization is used to derive the nonlinear coordinate transformation matrix and state feedback law,and to realize the linearization of converter. With the linearized Brunovsky standard model as the new controlled object,the sliding mode controller is designed by the exponential approaching law. Simulation results show that,the proposed control is better than the traditional PI control and the differential geometry -based optimal control in steady state property,response performance and robustness.