To reveal the effects of different signal types, as well as their frequencies and amplitudes, on the accuracy of parameter identification and control performance in the signal injection method for permanent magnet synchronous motor，a comparative analysis through simulation and experimentation was conducted on four signal injection methods: square wave, trapezoidal wave, triangular wave, and sinusoidal wave. Firstly, according to the characteristics of the injected signals, square and trapezoidal waves are categorized as locally constant signals, whereas triangular and sinusoidal waves are categorized as globally time-varying signals. Based on the forgetting factor recursive least square, two categories of parameter identification models for signal injection methods are constructed. Secondly, simulation analysis is performed to investigate the effects of the frequency and amplitude of the two categories of injected signals on the identification results of the parameters pending identification. Comprehensively considering the identification accuracy of each parameter requiring identification, the frequency and amplitude of the injected signals is judiciously chosen. On this basis, comparative analysis of the parameter identification results is conducted and the control performance of the system is evaluated among the four signal injection methods. Finally, an experimental platform is set up to validate the parameter identification through experiments. The outcomes demonstrate that although parameter identification accuracy of locally constant signal injection is higher than that of globally time-varying signal injection, the former has a greater influence on control performance of the system compared to the latter. Among the tested signal injection methods, trapezoidal wave injection achieves the highest identification accuracy, while triangular wave injection has the least effects on the control performance of the system.