With the development of the times and continuous improvement in modern motor control technology, permanent magnet synchronous motors (PMSMs) are widely used across various industries due to their simple structure and ease of operation. However, in practical operation, PMSMs tend to produce current harmonics, which increase losses, generate heat, and reduce the efficiency and lifespan of the motor. This paper focuses on suppressing current harmonics, with harmonic injection PMSM as the research subject. It analyzes the traditional compensation voltage acquisition method based on Deadbeat Predictive Current Control (referred to as “compensation voltage acquisition method based on DPCC”) for suppressing current harmonics. Building upon this analysis, it proposes an improved compensation voltage acquisition method based on Modified Deadbeat Predictive Current Control (referred to as “compensation voltage acquisition method based on TSD-DPCC”). Finally, the effectiveness of the proposed method is verified through simulation results using the Matlab/Simulink platform.