Single-bit modulator based controller for capacitive power transfer system

This paper proposes a single-bit ADC system based Proportional and Integral (PI) controller to regulate the output voltage of Capacitive Power Transfer (CPT) systems. A simple single-bit ADC system i.e., Single-Bit Modulator (SBM) is considered as an alternative to the commonly used multi-bit ADC systems. Unique features of employing SBM are 1) its ability to convert analog signals into single-bit signals and 2) its easy integrability in digital chips with linear variable differential transformers (LVDTs) such as FPGAs. A SBM based PI (SBM-PI) controller is designed which guarantees consumption of less hardware resources, latency and effectively regulates the output voltage to provide the desired power transfer efficiency. The performance of the proposed SBM-PI controller is compared to that of a conventional multi-bit PI controller and has been shown that both controllers give identical performance. However, the SBM-PI consumes significantly less hardware resources. The effectiveness of the proposed controller with SBM-PI is further demonstrated using the experimental prototype of CPT using 16 MHz ATmega8 microcontroller. The experimental results from a laboratory prototype illustrate that SBM-PI controller successfully regulates the output voltage of CPT to control the power flow.