Three phase construction

For a VHM to produce a balanced three phase output each phase must be such that the relative position of its magnets and stator teeth are 120 electrical degrees out of phase. Physically this is achieved by adjacent phases being separated by a multiple of two thirds of a rotor pitch.

There are two formats of structure which will achieve this. The more traditional approach, commonly used in rotary machines, is to have the three phases interspersed with each other, allowing the flux from differing phases to share the same return path. Preliminary studies conducted using FEA revealed that this layout was inappropriate as the three phases would no longer act independently. The flux pattern of each phase would stray significantly into the path of the other phases. Modelling of such a system

would require the development of a complex set of inter-phase current and position dependent inductance equations. To avoid this a second topology of machine is used where each phase is magnetically isolated from the others, allowing them to be treated and analysed separately. Each phase core back consists of a single C-core supported independently from its neighbours, eliminating the inter-phase back iron. Adopting this modular approach provides a high degree of flexibility in the design and choice of power ratings and results in a reduction in the total amount of steel used. A diagram of one such phase is shown in Figure 4.1.

Figure 4.1: Dimensions of the VHM
Renewable Energy Eco Friendly

Renewable Energy Eco Friendly

Renewable energy is energy that is generated from sunlight, rain, tides, geothermal heat and wind. These sources are naturally and constantly replenished, which is why they are deemed as renewable.

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