Extremely precise position estimation in sensorless control of permanent magnet synchronous motors using all-pass filter

For the stator flux linkage estimation to realize permanent magnet synchronous motor ssensorless control, a quasi-integrator is often substituted instead of a pure-integrator, resulting the position estimation error in a low speed region. This paper presents a new position estimation for sensorless control of PMSM using all-path filters, which realize extremely precise estimation under transient condition as well as steady state.