Accurate Rotor Position Estimation in Encoderless PMSM Drives With an Error Mitigation Method

This paper explores the significance of accurate rotor position estimation in field-oriented control (FOC) of surface mounted permanent magnet synchronous motors (PMSMs). Despite advancements, challenges such as inverter nonlinearity, control delays, low-pass filtering, and parameter variations can lead to significant error in estimation of rotor position, thereby impacting drive system reliability and efficiency. Quantifying position error in high-speed motor drive systems is complex due to the diverse and variable impacts of numerous non-ideal factors. To eliminate the estimation error, a novel rotor position error compensation method is proposed. The proposed method is straightforward and efficient, requiring no additional signal injection or complex calculations, thereby simplifying implementation while ensuring excellent dynamic and steady-state performance. The compensation strategy works by adaptively adjusting a compensation angle to maximize the quadrature voltage component in the estimated rotor reference frame. This adjustment aligns the estimated and actual <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dq</i>-axes, thereby eliminating position errors caused by non-idealities such as inverter nonlinearity, delays, and parameter mismatches. This method eliminates the estimation error regardless of its type of non-ideal origin. The validity of the proposed solution was verified by several simulations in the PLECS environment. Finally, experimental results are provided to verify the efficacy of the proposed compensation method.