Design and Analysis of Counter-Rotating Dual Rotors Permanent Magnet Compensated Pulsed Alternator

This paper presents the methodology for the electromagnetic design and analysis of air-cored pulsed alternators, which is based on a new type counter-rotating dual rotor permanent magnet compensated pulsed alternator (CRDR-PMCPA). The application of the CRDR topology in the field of CPA is used to decrease the large transient torque transmitted to the combat vehicle platform. Based on the air-cored structures and the pulse operation duty, the special design flowchart was presented. Halbach array permanent magnet rotors were designed for using the characteristic of unilateral magnetism gathering in the CRDR-PMCPA. The parameters of the air-cored dual rotors pulsed alternators were calculated and compared by the analytical method and finite-element analysis (FEA) method (FEM). The inductance of the armature winding is important for obtaining the pulsed current waveform accurately. The inductance of the armature winding is calculated by the numerical method and FEM, respectively. The mechanical design of the CRDR-PMCPA was done. The transient discharge process was simulated in detail for evaluating the design performance, and the operation risks of permanent magnets were also evaluated. The special problems for dual rotors rotating were investigated. The electromagnetic design and analysis is the base for accurately calculating the transient thermal rise and mechanical impulse aspects. Thermal and structural analysis was done by the multiphysics coupling analysis. And the results were used to evaluate the demagnetization risk of permanent magnets and evaluate the safety of the whole machine and the discharge system.