Adaptive Resistance Control Solutions in an Assisted Coding Environment
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This thesis focuses on the implementation of a human energy harvester’s resistance control scheme for a full capacitance boost converter, low capacitance boost converter, and a voltage controlled attenuator. The boost converter control schemes utilize an adapted PFC ACMC boost converter topology with input resistance as a controlled feedback variable for the current loop, while disregarding the output voltage resistance. The electronic module’s power draw affects the applied resistance felt by the user. The prototype outputs a nominal 10W of power for the emulated 2.5Ω full load. Previous research has enabled constant resistance, threshold resistance, and variable resistance control implementations on a boost converter coded in Code Composer Studio’s C/C++ environment. The first goal of this thesis sought to eliminate or minimize the necessary C/C++ coding required for resistive control. This was achieved through the implementation of MATLAB Simulink’s Embedded Coder’s C2000 Library coding environment, using a block diagram control scheme with integrated MATLAB coding. Three control schemes are proposed: Ramp and Hold, Optimized Resistance, and Power Regulation control algorithms. The Ramp and Hold scheme targets the decoupling point between the motor and the input encoder. The control method increases from light to full load peaking and holding the full load condition at this decoupling point to target the energy harvester’s negative work period. The Optimized Resistance algorithm averages the user’s average voltage at light load, and then increments the resistance until this voltage begins to drop, indicating a change in the user’s kinematics. The Power Regulation control scheme programs a required average output power per step for the user, and dynamically alters the resistance felt by the user to achieve this goal. The final boost converter had a peak efficiency DC of 93.4% for 25W input power at Vin=20V and Rin=15Ω. The linear regulator voltage controlled attenuator acts as a simple resistive load to dissipate the entire 10W input power, using the low side MOSFET for power dissipation. The three control schemes were implemented and tested on a boost converter with a 2200µF, 940µF, and 47µF output capacitor. Integrated improvements to the system and future work are then proposed.