Control design for a high performance amplitude/phase modulated digital-to-synchro switching power converter

For a high performance three-phase switching digital-to-synchro (D/S) power converter to drive the synchro motor, not only the precision control is needed, but also the control strategy to avoid stall condition is necessary. For the precision angle control, an amplitude/phase modulation algorithm can be implemented using digitally controlled sinusoidal pulse-width-modulation. For the control strategy to avoid stall condition, a novel kick-off algorithm is developed to improve the system transient response. In addition, a nonlinear closed-loop control strategy is proposed to enhance the generated torque when the synchro is under loaded condition. A 500 W prototype unit has been built and tested. Hardware experimental results are given to verify the performance and control design.