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单闭环速度控制系统如图:在第一章里我们已经了解了单闭环速度控制系统的结构和工作原理。第三章自动控制系统的数学模型irific-∞+++-udidM+-TGnufC0R0/2R0/2R1R0un+uctKsC1单闭环速度控制系统的原理图:系统的组成:比较环节和速度调节器晶闸管整流器直流电动机测速发电机ic=ir–ifIc(s)=Ir(s)–If(s)数学模型的建立与化简举例1．比较环节和速度调节器第五节数学模型的建立与化简举例R0C04T0=τ1=R1C1Uct(s)=Uf(s)T0s+1]τ1S(τ1s+1)Kc[Un(s)-式中:代入电流平衡式得:Un(s)R0Ir=If(s)=Uf(s)R0(T0s+1)Ic=–τ1sUct(s)(τ1s+1)R1动态结构图Un(s)1T0s+1Uf(s)_Kc(τ1s+1)τ1sUct(s)Kc=R1/R0式中:2．功率放大环节Ks3．电动机部分4．速度反馈环节前面已求得电动机动态结构图—速度反馈系数第五节数学模型的建立与化简举例—放大倍数KsfUd(s)=KsUct(s)Uf(s)=Ksf·N(s)速度控制系统的动态结构图第五节数学模型的建立与化简举例Kc(τ1s+1)τ1sKa1/Rd1+TdsRdCeTmsCeN(s)KsfT0s+1__Ed(s)Uct(s)Ud(s)Id(s)_IL(s)Un(s)二、系统的传递函数动态结构图进行等效变换和化简后可得：第五节数学模型的建立与化简举例与闭环控制系统的典型动态结构图比较：G1(s)G2(s)H(s)Un(s)KsfT0s+1IL(s)KcKS(τ1s+1)Rdτ1s(Tds+1)Rd(Tds+1)Ce(TmTds2+Tms+1)N(s)__1．系统的开环传递函数第五节数学模型的建立与化简举例Gk(s)=G1(s)G2(s)H(s)τ1s+1)KcKs(τ1sRd(Tds+1)G1(s)=KsfT0s+1H(s)=Rd(Tds+1)Ce(TmTds2+Tms+1)G2(s)=Ce(TmTds2+Tms+1)=τ1sKcKsKsf((T0s+1)τ1s+1)2．系统的闭环传递函数给定信号Un(s)作用时IL(s)=0Un(s)N(s)1+G(s)H(s)G(s)=Ce(TmTds2+Tms+1)=τ1sKcKs((T0s+1)+τ1s+1)(T0s+1)KcKsKsf(τ1s+1)扰动信号IL(s)作用时Un(s)=0-IL(s)N(s)1+G(s)H(s)G2(s)=Ce(TmTds2+Tms+1)=τ1sRd(T0s+1)+τ1s(T0s+1)KcKsKsf(τ1s+1)(Tds+1)G(s)=G1(s)G2(s)3．系统的误差传递函数第五节数学模型的建立与化简举例Ce(TmTds2+Tms+1)=τ1sCe(T0s+1)+τ1s(T0s+1)KcKsKsf(τ1s+1)(TmTds2+Tms+1)给定信号Un(s)作用时IL(s)=0Un(s)E(s)1+G(s)H(s)=1扰动信号IL(s)作用时Un(s)=0-RdKsfCe(TmTds2+Tms+1)=τ1s(T0s+1)+τ1s(Tds+1)KcKsKsf(τ1s+1)-IL(s)E(s)1+G(s)H(s)=-G2(s)H(s)返回