Generator and Electrical System - Small Wind Turbines: Analysis, Design, and Application - page 230

Fig. 11.2 Outside and inside views of the Ginlong 500-A PMG. The casing outer diameter is
250 mm. The maximum shaft diameter is 34 mm. The 16 permanent magnets are attached to the
rotor and the back bearing is clearly visible in the bottom photograph. Both photos by Brandon
Ferguson
in efficiency. For a wind turbine, which must operate efficiently over a wide range
of loads and frequencies, better load matching is needed. For the rectifier/con-
troller-inverter topology shown in Fig. 11.3 matching can be achieved through
pulse-width modulation (PWM) as explained in Sect. 11.4 . The PMG produces
three-phase power of varying voltage and frequency which is normally rectified to
DC. If the turbine is charging batteries then they would replace the inverter in
the schematic. This possibility may have been in the mind of the designer of the
Ginlong 500-A PMG as the DC bus voltage slightly higher than 24 V which is one
of the common voltages used in battery banks for remote power systems.