Synchronous machine control device without position sensors

In the disclosed control device without position sensors which controls a synchronous machine having a multiple winding configuration, integration processing is performed to integrate phase estimation information of multiple inverters even when there exists an imbalance in the voltage and current information from the multiple windings, and the disclosed control device is capable of simplifying sharing of control elements and communication of control information in said integration processing. One winding of a synchronous machine having a double winding configuration is driven by a master inverter, and the remaining winding is driven by a slave inverter. For both inverters, estimated phase angles delta phi e1 and delta phi e2 are calculated from rotating coordinate voltage commands and current detection signals, and a circuit constant of the motor and estimated velocity. An average value calculation unit (20) calculates average values of the estimated phase angles, a velocity estimation unit (12) calculates estimated velocity omega re from the average value, and a position integration unit (13) integrates the estimated velocity over time to calculate an estimated reference phase theta. The average value calculation involves a configuration performed after velocity estimation or a configuration performed after position integration.