Identification Modeling And Dynamic Analysis Of Contactless Synchronous Machine Rotor Excitation System

Vehicle-mounted motor as the core component of new energy vehicles, its performance will directly affect the operation of the vehicle. To eliminate the potential security risks of brush and slip ring, brushless vehicle-mounted motor has become an inevitable development trend, but present domestic and international brushless schemes all need to be added additional winding or devices which will complex the machine structure, increase the volume, lower the motor utilization rate. To solve the problems above, this dissertation puts forward a contactless synchronous machine rotor excitation (CSME) method,which introduces contactless energy transmission technique into motor excitation system and replaces the brush and slip ring with relatively rotating high frequency converter and brushless excitation. This method has a wide range of applications which not only can be used in electric excitation machine systems,but also in hybrid excitation machine systems.In this dissertation, the basic structure and operating principle of CSME system is discussed, the work mechanism of contactless excitation converter is introduced and the structure of brushless integration machine which can be applied to CSME system is designed.To solve the problem of poor compatibility and low portability of each function module that caused by the complexity of contact excitation system topology and compensation circuit, an estimate initial value recursive least squares (EIV-RLS) identification modeling method is proposed in this dissertation, which owns the advantages of good versatility and portability.Identification modeling only need to sample and transform the input and output data,and judge the system order by Akaike information criterion (AIC),and then obtains system parameter estimation by EIV-RLS algorithm and small signal model of system. Through MATLAB/Simulink, least squares (LS), zero initial values RLS (ZIV-RLS) and EIV-RLS identification modeling for S-S type CSME system are respectively simulated .The accuracy of three methods and verified the generality of EIV-RLS identification modeling method is compared and analyzed though experiments.The high frequency transformer of contactless excitation system works under condition of relatively high-speed rotating, and to study if there is any effect of this unique working status on transmission efficiency, adjacent and coaxial winding structure which can work at the unique state are put forward.The 3D transient characteristics under relative high-speed rotation of these two kinds of transformer is simulated though ANSOFT/Maxwell software,the transient flux density, the transient magnetic flux leakage and current density are respectively analyzed. After comparing the simulation results, adjacent winding structure is selected as the high frequency transformer for contactless excitation system and the iron core material and air gap are also analyzed in this dissertation.The influence of leakage inductance can not be ignored any more because the contactless transformer has a big air-gap. The increase of leakage inductance will decrease the coupling coefficient and reduce the transmission efficiency of contactless excitation converter. Using the resonance principle to compensate the leakage inductance of contactless transformer can improve the energy transfer efficiency of contactless excitation system. The mutual inductance model which is the most suitable model for contactless transformer is adopted. Though introducing the concept of mapping impedance,the matching method of compensation capacitor in four basic compensation networks is given , and the power transmission characteristics of four basic compensation circuits is analyzed . In order to avoid frequency bifurcation phenomenon and sustain the system stable, the stable operation condition of basic compensation networks is derived .According to the state variable method, the contactless transformer model is established and by comparing the simulation results in MATLAB/Simulink environment, good compensation effect of the series-series compensation network is verified. On the basis of mathematical model of the contactless excitation synchronous machine power generation system, each functional module is respectively established and through the results of the simulation, the dynamic characteristics of contactless excitation synchronous machine power generation system is detected.Finally, the experimental platform of contactless excitation system is constructed and a claw-pole generator prototype with contactless excitation system is developed. By testing the compensation characteristic and rotating performance of contactless excitation system, the correctness of the proposed method and simulation results are verified. At the same time, through the test of the contactless excitation synchronous machine power generation system performance,the effectiveness, feasibility and the practical value of CSME method are verified.