Performance Analysis and Optimization of Built-In Permanent Magnet and Salient-Pole Electromagnetic Hybrid Excitation Generators for Vehicles

Table 1

Comparison of topology structure and performance of HEG.

Category	Feature	Name	Topology structure	Advantages	Disadvantages
Parallel HEG	Two magnetic potential sources are on the stator and rotor, respectively	Alternating magnetic pole HEG	PM steels are attached to the rotor, and excitation winding is wound on the stator core.	The alternating magnetic pole structure effectively reduces the amount of PM materials, and the volume is relatively small.	The excitation winding occupies the armature winding space and magnetic field space, and the output power of the generator is reduced.
	Two magnetic potential sources are on two rotors	PM and claw-pole electromagnetic HEG	The PM rotor and the claw-pole electromagnetic rotor are coaxial and parallel, and they share the same stator.	The magnetic field distribution of the two rotors can be adjusted, and HEG can achieve large output power.	The axial length of the double rotor structure increases, the volume of HEG increases, and the weight is relatively large.
Series HEG	Claw-pole series type	Claw-pole series HEG	The excitation winding is wound axially in the claw-pole flange, and the PM steels are installed in the middle of two claws.	PM steels reduce magnetic leakage between claws and do not occupy additional generator volume.	The claw-pole structure has more magnetic leakage, a small power density, and a large weight.
		Doubly salient-pole hybrid excitation flux switching generator	The stator is composed of stator blocks, the PM steels are sandwiched between the stator blocks, and the excitation winding is wound on stator blocks.	Small size, simple rotor structure, and high-speed operation.	The excitation winding occupies the space of armature winding, and the generator has large vibration and noise.
	Salient-pole series type	Salient-pole HEG with the variable magnetic pole	Changing some magnetic poles, canceling the excitation winding, and building in PM steels.	The PM magnetic field does not occupy additional volume and the generator is small.	During the excitation regulation, the EEMF is not equal to the PM magnetic field, which will affect the distribution of the main magnetic field.
		The designed HEG	Changing the structure of salient-pole shoe and building in combined-pole PM steels.	HEG is mainly based on PM magnetic field and has less excitation loss, small volume, and high power density.	The structure of changing pole shoe increases the winding cost of excitation winding.