Efficient generator stays cool and does not cog

Generators from Clean Energy range from 1 kW to 500 kW in eight models.

Clean Energy Technologies, Calgary, Alberta, Canada  is said to have developed a generator for wind turbines that is more efficient than existing designs. The company’s Axial Flux Permanent Magnet (AFPM) generators work at high efficiencies and produce more power at lower wind speeds due to a coreless design. The generators eliminate traditional cogging issues which makes them well suited for wind-turbine applications.

Traditional or radial-flux permanent magnets (RFPM) orient the magnetic flux outward or radially from the turbine shaft while the AFPM design works by orienting the magnetic flux along the axis of the turbine shaft. A coil wraps around a disc at the center axis. Magnetic discs then rotate on the sides of the coil disc and generate electricity. This kind of power generation is said to be ideal for wind power applications because its initial operating torque (cut-in speed) is lower than existing RFPM methods.

AFPM power generation divides into inner and outer classifications. With an inner configuration, only the magnetic disk rotates while the generator housing remains fixed. In the outer configuration, the whole generator body rotates by fixing the magnetic disk to the body. Application requirements determine the configuration.

There is another consideration. A generator producing electricity also produces heat. As the heat increases, efficiency decreases. To solve this problem, Clean Energy generators are liquid cooled. This significantly reduces, says the company, the wear that high temperatures cause, and thus improves the generator’s life-span. The table compares a few details of the competing designs.