A FPGA implementation of resolver-based absolute position detector

Absolute position detector which not only perceives the absolute position of the rotary machine but also outputs switch data according to the given angle is one of the major equipment in the field of factory automation. Absolute position detector is composed of sensor module and its controller. In this paper, a sensor controller is implemented using FPGA with VHDL. This chip has a less form factor than conventional circuit. A test shows reliable precision within THE) (total harmonic distortion) of 0.2% which can be applicable commercially. Additionally, two compensation methods are proposed. One is to fit RVDT input conditioning wave, and the other is how to stabilize the output count value in accordance with the sensor and FPGA processing speed. In the future, more research will be conducted to enhance the precision by the introduction of 3-phase transformer.