Analysis Of Electromechanical Coupling Facts And Decoupling Control Strategies For Complex Electromechanical Systems

Taking Analysis of electromechanical coupling facts and decoupling control strategies for complex electromechanical systems as a main topic,this doctoral dissertation researches the dynamic coupling relation between nonlinear harmonic current and main motion of complex electromechanical system;analyzes electromechanical coupling types,characteristics and their acting laws;explores coupling modeling method,optimal parameter tuning method and decoupling control methods of complex electromechanical systemjand realizes decoupling control among the forward tension,the backward tension and the main drive speed of a typicalcomplex electromechanical system--CM04 temper mill.The main ideas areexpressed as following:The study investigates thoroughly the electromechanical drive subsystems of thetypical complex electromechanical system--CM04 temper mill.It proposes a totaltesting scheme of the system,designs signal isolating buffers with high fidelity,solves the difficult problem that the real signals of harmonic currents are picked up from the main armature circuit with high voltage and strong current,meantime,the normal work of the system is not affected at all. It finds the law that the harmonic currents act on working states of temper mill,confirms that the harmonic currents are one of the causes which results in singular operating mode,coupling chatter,and leads to shade and light streaks on the surface of strip steel.It puts forward a analyzing and computing method of harmonic current of multiphase rectifying circuit.By this method,we compute theoretically the harmonic currents in the 3-phase-bridge circuit of temper mill.The theoretical results are testified by the measuring values and vice versa.Therefore,the computing method is practical and the measuring values are trustworthy.The study presents a coupling modeling approach of complex electromechanical system.Complex electromechanical system consists of electromechanical components.No matter how complex it is,it can be generally decomposed electromechanical components or equivalent electromechanical components. Connecting correctly these component symbols according to the structural principle of electromechanical system,we can get all dynamic equations of electromechanical loops.Aiming at a class of complex electromechanical systems,such as 4-high or multi-high cold mills and continual mills,we firstly construct mathematical models of every subsystems by means of structural principle modeling method;nextly,get theoverall mathematical model of electromechanical drive system by joining together these subsystems' models according to coupling variables and parameters; we finally simplify the overall model according to time-scale principle which can retain main eigenvalues and significant state variables, and obtain a practical mathematical model of complex electromechanical system. By simulating the CM04 temper mill's model constructed by above-mentioned method,we test and verify that the modeling method is effective and practical.The study analyzes and researches the electromechanical coupling facts and acting laws existing in complex electromechanical system.lt summarizes four modes of electromechanical couplings.They are electromagnetic torque direct coupling,harmonic torque direct coupling,microvariable control loop coupling and multi-drive system coupling by workpiece.Among them,the electromagnetic torque direct coupling occurs in electromechanical energy conversion through electromagnetic field between stator and rotor of electric motor,it is basic mode implementing design functions,and it is also a main physic process existing universally in electromechanical system;the harmonic torque direct coupling disturbs main motion states of system;the microvariables are also a disturbance to main motion,they and dynamic parameters form parameter weak coupling;the harmonic currents get into current-adjusting system via current feedback units, and is amplified by current regulator, then act on mechanical main motion again,this coupling action affects more sev...