Modified efficiency optimization control for fractional slot concentrated wound interior permanent magnet synchronous generators

A new control approach for maximum torque per ampere control is proposed to improve the efficiency of fractional slot concentrated wound interior permanent magnet synchronous generators under light load conditions. The proposed method is compared with existing current reference trajectories (id zero, conventional maximum torque per ampere and total loss minimization) by experimentally measuring the generator efficiency. The generated power is delivered to the grid through a fully controlled back to back converter. The generator-side converter regulates the speed of the generator while the grid-side inverter is responsible for maintaining a constant dc link voltage. The steady-state analysis of efficiency taken at rated speed shows the effectiveness of the new control compared with id zero control and conventional maximum torque per ampere control. Moreover, efficiency can also attain the same values as loss minimization control for particular operating points after modifying the control approach while operating along the same maximum torque per ampere trajectory. The technique provides the same dynamic performance as the conventional maximum torque per ampere control. Field oriented control based on space vector modulation is adopted for generator control.