Hardware design implementation issues of the estimator-based controller using FPGA

Abstract

ABSTRACTHardware implementation issues play a vital role to realize the system accurately. Realization of hardware in digital domain has more advantages than analog domain. Field programming gate array (FPGA) based architectures are suitable for fast and reconfigurable systems. In this paper, implementation issues of an estimator based controller using FPGA are discussed. Verilog coding is developed to defeat these issues and efficient hardware mapping is derived. Input signal processing is proposed to overcome the analog to digital converter (ADC) interfacing issues such as quantization, sampling rate, resolution, non-linearity error and offset error. Optimum bit sizing of digital control modules are derived, considering system requirements and specifications. Controller operations are analyzed in binary form to choose the bit size of various operands and control modules, to derive accurate results. In this application, a 16-bit control architecture is proposed to estimate states of the converter and to generate control signals. Estimator based controller is designed for a dc-dc converter. Atlys Spartan-6 XC6SLX45 FPGA is used to implement the controller. Implementation issues such as ADC errors, settling time, the bit size of variables, quantization effects of the estimator and controller are mainly focused. It enables verilog coding quite easier to implement non-linear controllers using FPGA.