Inverter nonlinearity in Permanent Magnet Synchronous Motor (PMSM) speed control systems introduces voltage errors, leading to current harmonics. This paper proposes a comprehensive compensation strategy to address these issues. First, all sources of inverter nonlinearity are collectively modeled, and a phase voltage error equation is derived based on Kirchhoff’s voltage law. An iterative linear interpolation method is employed to calibrate the nonlinear relationship between phase voltage error and current, generating a look-up table (LUT). During operation, the phase voltage error is dynamically compensated using the LUT based on the phase reference current. The voltage error is then converted into an equivalent time error to directly adjust the control signals of the power devices. To enhance robustness against sampling noise and LUT instability, a real-time time error correction strategy based on a Proportional-Integral (PI) controller is introduced. Experimental results demonstrate the effectiveness of the strategy in suppressing harmonic currents and speed regulation performance.