Research on the Four‐Quadrant Operating Mechanism of a Hybrid Excitation Generator With Magnetic Field Modulation and the Power Distribution Ratio Between Permanent Magnet and Magnetic Field Modulation

ABSTRACT The hybrid excitation generators combine the advantages of permanent magnet generators (PMGs) and electrically excited generators (EEGs), offering significant potential for power generation systems. However, there has been little research on the operational on the operational mechanisms of the excitation current I f and the excitation voltage U f with constant output voltage and the ratio of the magnetic field modulation power P FM to the permanent magnet power P PM . This study uses a tangential concentrated magnetic parallel structure hybrid excitation generator as an example to construct a field‐circuit coupled power generation system model. The working principle, voltage phase diagram, and loss calculations are detailed, and the four‐quadrant operation mechanism of the field modulation magnetic part (FMMP) is examined. The magnitudes of P FM / P PM and power generation efficiency under different load types are analyzed for both no‐load and rated voltage scenarios. Based on the no‐load voltage, simulation results show that the FMMP operates under resistive and inductive loads in the first quadrant. In contrast it operates in the third quadrant under capacitive loads. The P FM / P PM ratio reaches its highest value, with an average of approximately 0.018. Resistive and inductive loads achieve power generation efficiencies of up to 97.75% and 98.09%, respectively, whereas capacitive loads exhibit efficiencies ranging from 64.88% to 56.57%, with a maximum efficiency of 75.56%. Based on the rated voltage, the FMMP operates in the first, second, and third quadrants under resistive loads, in the first, third, and fourth quadrants under inductive loads, and in the third quadrant under capacitive loads. The P FM / P PM ratio reaches its highest value, averaging approximately 0.027. The maximum power generation efficiency is 93.73% for resistive loads, 94.14% for inductive loads, and 72.16% for capacitive loads. This indicates that the generator's voltage stability can be maintained with a relatively small excitation current, but the characteristics of different loads significantly impact generation efficiency and power distribution.