Sensorless vector control for hermetic reciprocating compressor

This paper presents a sensorless vector control algorithm applied to a hermetic reciprocating compressor of a conventional refrigeration system. The single-phase induction motor of conventional on/off refrigerator is driven in variable speed to improve the thermal performance of the system. A sensorless technique is necessary because the conventional speed sensor cannot be employed in the hermetic compressor. To overcome this drawback, a model reference adaptive-system is used to estimate the mechanical speed of a single-phase induction motor. The electrical parameters of machine are needed to set the speed estimator and to implement a vector control. The classical tests to obtain the electrical parameters are a difficult task in hermetic compressor. Thus, a recursive least-square algorithm is used for parameter identification. The high performance speed control of hermetic compressor is shown and the experimental results are provided and discussed to validate the proposed algorithm.