2.1 high temperature superconducting rotating motor topology

Figure 1 for a 6 pole (3 for) high temperature superconducting Marine propulsion motor topological structure. It USES coreless

armature winding and the first generation of HTS wire (BSCCO - 2223) excitation winding.
Figure 1. Typical 6 extremely high temperature superconducting Marine propulsion motor topology
High temperature superconducting motor rotor and the traditional motor rotor completely different, its excitation winding by

high temperature superconducting materials, operating in a closed low temperature (35-40 k) environment. Rotor assembly

including high temperature superconducting excitation winding, support structure, the cooling circuit, cryostat and

electromagnetic shielding. The cryogenic refrigeration unit module Settings in a fixed frame, helium is used to
rotating joints cooling rotor component.
Stator winding is the improved copper wire winding. Stator assembly including exchange stator winding, stand core, stator

winding bracket, bearing and casing. Stator winding not on conventional core tooth, because they by high temperature

superconducting winding produce strong magnetic field and in the saturated state. Stator by fresh water cooling.
2.2 energy conversion efficiency and power density
The emergence of high temperature superconductivity for large motor technology progress created opportunities, dramatically

changed the rotating machine operation efficiency.
As is known to
rotary union all, mechanical/electrical energy

conversion efficiency is a recognized as variable function, variable including motor geometric structure, core in the presence

or absence of a rotor and rotor winding wire composition and so on. And many factor, the influence of the biggest variable is

rotor winding materials.
High temperature superconducting motor are so efficient, because of high temperature superconducting wire can be bearing ratio

the same size and weight of copper wire high 140 times the current. More current means more magnetic flux density and more

powerful magnetic field, this directly increased motor magnetic shear stress (σ = around the armature current load A × middle

air gap flux density peak B), it means that unit mass can provide greater torque (Ta). Although superconducting material in

maintaining low temperature environment need to consume energy, but low temperature cooling system the power needed is quite

low, about conventional rotor copper loss of about 10%.
Marine propulsion high temperature superconducting motor torque can be obtained under reference type:
Ta = σ D / 2 kh
Type, D for intermediate air gap diameter, K and h is material weight density and radial the height of the product. Thus it can

be seen magnetic shear force on low speed propulsion motor the role.
It is important, the high temperature superconducting motor in the whole operation of the power range, are always maintain high

efficiency. Large high temperature superconducting motor in full load condition runtime efficiency as high as 99% above. Figure

2 for a typical high temperature superconducting synchronous Marine motor efficiency and output power curve. The calculation

results include the high temperature superconducting motor cooling system of power loss. Curve shows that high temperature

superconducting motor almost effectively close to ?
fiber optic rotary joint optic rotary joint the maximum operating conditions, and completely don't take account of ship speed. The study also

revealed that, in some assume that case, the high temperature superconducting electric propulsion system can even reach and

diesel direct propulsion ship fuel and lubricating oil consumption level.
Figure 2 typical Marine HTS motor running efficiency