Low-Complexity Finite Position Set-Phase Locked Loop Based on Inverse Function Construction for Sensorless Control of Dual Three-Phase PMSM

Finite position set-phase locked loop (FPS-PLL) has been extensively studied by scholars in recent years as a sensorless technology due to its advantages of parameterless tuning and excellent dynamic performance. However, compared to bandwidth-based quadrature phase locked loop (PLL), such methods impose a higher computational burden on microprocessors. To tackle this issue, this article proposes a low-complexity FPS-PLL applied to sensorless control of dual three-phase permanent magnet synchronous motors (DTP-PMSMs). The proposed FPS-PLL strategy divides all positions into 12 sectors by judging the polarity of back-electromotive forces electromotive forces (EMFs), ensuring initial approximation errors remain within π/12. Furthermore, it introduces a normalization-free iterative strategy that achieves a theoretical accuracy of 6.96e⁻⁹ rad in merely two iterations. The convergence analysis and theoretical calculation accuracy are given. The entire computation process avoids employing complex operations such as square root and arctangent functions, thereby further improving computational efficiency. Finally, experiments are carried out on the DTP-PMSM driver platform to verify the superiority of the proposed FPS-PLL.