Research On Steady-state Model And Electromagnetic Parameters Of High And Low Voltage Dual-winding Induction Generators

In order to realize the low-voltage reactive power compensation of high-voltage induction generator,a high-low voltage dual stator-winding induction generator is proposed which is a complex multi-loop nonlinear system.This paper mainly studies the high-low voltage dual stator-winding induction generator under steady state.The steady-state model considering the magnetic leakage flux coupling between two sets of stator windings is established.Based on the electromagnetic relationship and the voltage equation of natural coordinate system,the voltage equations of stator-winding branchs are derived,where the mutual leakage electromotive force is expressed as the voltage drop of the impedance parameter which represents the magnetic leakage flux coupling.According to the voltage equations,the steady-state equivalent circuit is established where the mutual leakage electromotive force is expressed as a current-controlled voltage source,which realizes the equivalence of the magnetic leakage flux coupling between two sets of stator windings.The basic parameters of the steady state model are calculated.For the complex stator structure of high-low voltage dual stator-winding induction generator,the calculation of stator leakage inductances and their equivalent parameters is mainly introduced.The incidence matrix is introduced to reflect the change of the angle between two sets of stator windings,and the stator leakage inductances and their equivalent parameters of different angles are calculated and analyzed.Verification experiments are designed based on the three-port characteristics,which realizes the separation of the resistance parameters of each side and verifies the equivalent parameters of mutual leakage inductance.The validity of the calculated results was illustrated by comparing with the experimental ones.The saturated magnetizing reactance is calculated based on the distributed magnetic circuit.The flux density of each air-gap node is calculated iteratively according to the magnetic circuit equations of distributed magnetic circuits,and the flux density distribution and its fundamental component are determined.Furthermore,combining with the circuit relationship,the magnetizing reactance variation curve is obtained,and the magnetizing reactance under given voltages is calculated iteratively.The calculation results are consistent with the results of synchronous no-load experiment,which verifies the accuracy of the calculation.The steady-state performance characteristics are calculated and analyzed under three states of no-load voltage build-up,load operation and voltage stabilizing operation.Based on the equivalent circuit,the loop current equations under different states are derived and the corresponding steady-state operation conditions are determined.The direct search method is used for optimal solution to calculate the steady-state operation performance.The calculation results are consistent with the experimental results,which shows the feasibility of the analysis method and verifies the accuracy of the established model and the determined parameters.The research work in this paper lays a foundation for the electromagnetic optimization design of the high-low voltage dual stator-winding induction generator,and provides theoretical support for the engineering application of the generator.