This study proposes a simple sensorless-control method for permanent magnet synchronous motors. The controller does not employ any phase-locked loop (PLL) blocks, which provide the angle of the rotating reference frame. The instantaneous-voltage-reference direction of the inverter is directly utilized for setting the angle of the gamma-delta frame. Experiments reveal that the proposed controller appropriately drives a 400W IPM motor almost without any motor parameters. Additionally, the drive system achieves a high transient performance in terms of motor speed.