Analysis And Research On The Loss Of Electrically Excited Synchronous Generator

The AC power used in modern times is almost entirely generated by synchronous generators.Three-phase synchronous generators have the advantages of good power supply quality and strong load capacity.They are widely used in large-capacity power systems or independent power systems.With the continuous increase of power supply,The development of efficient generators is particularly important.There are various losses in the operation of the synchronous generator.These losses will cause the motor to heat up.If the local overheating is severe,it will affect the performance of the generator and reduce the service life of the motor.Therefore,accurately calculating the loss of the synchronous generator will improve the efficiency of the motor and estimate its service life It is of great significance.This paper studies the loss of synchronous generators from theoretical analysis and numerical calculation,and explores measures to reduce consumption.The main study of electromagnetic phenomena is based on Maxwell's equations,introducing four laws and the steps of solving electromagnetic field finite element.Based on Maxwell's equations,the finite element model of the synchronous generator under no-load and load is established to lay the foundation for the calculation of motor losses.The theories and calculation methods of basic iron loss,rotor additional loss and copper loss under no-load / load conditions are introduced respectively.Considering the cogging effect of the motor,the iron loss separation model considering harmonics is obtained.The analytical method and the finite element method are used to calculate the basic iron loss of the stator under no-load / load of the motor.Based on the established no-load / load model,the additional loss of the rotor under the two working conditions of the prototype under study is calculated by the transient field.Use the analytical formula to calculate the stator and rotor phase resistance of the motor,and then obtain the stator and rotor copper consumption.The influence of parameters such as magnetic slot wedge,stator slot width,stator conductor strands,strand transposition,etc.on the motor loss was studied by using control variables.Discuss the changes of air gap coefficient,magnetic field,stator slot leakage reactance and loss under different relative permeability of slot wedge.The finite element method is used to obtain the relationship between the stator iron loss and the stator slot width.The formula of the resistance increase coefficient under different strands of the stator conductor is given to obtain the relationship between the additional copper loss of the stator and the number of strands of the stator conductor.Introduce the leakage inductance potential method and the multi-section field-circuit coupling method for calculating strand transposition.Compare the leakage inductance potential,current and loss of strands under transposition under the two methods to verify the effectiveness of the leakage inductance potential method in the calculation of prototype loss.The work done in this paper can provide theoretical guidance for the design and optimization of synchronous generators.