Patent ID: 7341432

Claim:
An operation control apparatus of a reciprocating compressor, comprising: a compressor including a searching coil; a first stroke estimator that estimates a first stroke value by using a voltage and a current applied to a motor of the compressor and a motor constant; a phase difference detector that detects a phase difference between a phase of the first stroke value and a phase of the current applied to the motor; a searching coil voltage detector that detects a voltage applied to both ends of the searching coil based upon the phase difference detected by the phase difference detector; a counter electromotive force extractor that extracts a counter electromotive force induced by the searching coil in accordance with the phase difference detected by the phase difference detector; a second stroke estimator that estimates a second stroke value based upon the extracted counter electromotive force; and a controller that compares the second stroke value with a stroke reference value and varies one of a voltage applied to the motor and an operational frequency of the compressor in accordance with a result of the comparison.