Automated tuning of a piezoelectric power harvesting cantilever beam via the application of an axial load

This thesis deals with automatic tuning of piezoelectric power harvesters. A prototype was constructed to verify the effect of the application of an axial load on a cantilever beam and the effectiveness of increasing the power harvested from a piezoelectric beam via axial loading. It was shown, experimentally, that the natural frequency of a piezoelectric beam harvester can be changed over a range of 25Hz. From the experimental results it was shown that the power can increase up to seven times when tuned in comparison to unturned. Computer simulations were used to demonstrate a closed loop tuning system’s ability to apply an axial load effectively onto a piezoelectric cantilever beam in response to ambient vibrations. The closed loop tuning system is a viable option for tuning and can lead to increased power when applying the axial load suggested by the tuning system.

Automated tuning of a piezoelectric power harvesting cantilever beam via the application of an axial load

This thesis deals with automatic tuning of piezoelectric power harvesters. A prototype was constructed to verify the effect of the application of an axial load on a cantilever beam and the effectiveness of increasing the power harvested from a piezoelectric beam via axial loading. It was shown, experimentally, that the natural frequency of a piezoelectric beam harvester can be changed over a range of 25Hz. From the experimental results it was shown that the power can increase up to seven times when tuned in comparison to unturned. Computer simulations were used to demonstrate a closed loop tuning system’s ability to apply an axial load effectively onto a piezoelectric cantilever beam in response to ambient vibrations. The closed loop tuning system is a viable option for tuning and can lead to increased power when applying the axial load suggested by the tuning system.

Closed Loop Tuning of Cascade Controllers Based on Setpoint Experiment

This study presents online PI/PID controller tuning rules for cascade control configuration. The necessary process data are determined with the help of a simple setpoint experiment in a single closed-loop mode with the proportional controller only. The obtained process data is recorded in terms of the overshoot, controller gain, peak time, and relative output change. The data is then utilized to establish a correlation with PI/PID settings through simulations. Further, the proposed PI/PID controller tuning rule for a single loop has been extended to the cascade control configuration. The inner loop controller is tuned first, and then the primary loop is tuned by considering a well-tuned inner loop as a part of the primary plant. Finally, simulation examples demonstrate that the proposed method delivers significant disturbance rejection and better setpoint response when compared to the recently reported methods from the literature. The proposed method is also able to deliver stable closed-loop performances when subjected to large parametric uncertainties and measurement noise.

Online Current Loop Tuning for Permanent Magnet Synchronous Servo Motor Drives with Deadbeat Current Control

High bandwidths and accurate current controls are essential in high-performance permanent magnet synchronous (PMSM) servo drives. Compared with conventional proportional–integral control, deadbeat current control can considerably enhance the current control loop bandwidth. However, because the deadbeat current control performance is strongly affected by the variations in the electrical parameters, tuning the controller gains to achieve a satisfactory current response is crucial. Because of the prompt current response provided by the deadbeat controller, the gains must be tuned within a few control periods. Therefore, a fast online current loop tuning scheme is proposed in this paper. This scheme can accurately identify the controller gain in one current control period because the scheme is directly derived from the discrete-time motor model. Subsequently, the current loop is tuned by updating the deadbeat controller with the identified gains within eight current control periods or a speed control period. The experimental results prove that in the proposed scheme, the motor current can simultaneously have a critical-damped response equal to its reference in two current control periods. Furthermore, satisfactory current response is persistently guaranteed because of an accurate and short time delay required for the current loop tuning.