In this article, we study the control by sliding mode (CSM) applied to the permanent magnet synchronous machine (PMSM) supplied with a tension inverter with triangulo-sinusoidal -MLI. The control by sliding mode is well adapted to the nonlinear systems. It is characterized by properties of robustness with respect to the external disturbances and parameters variations . The sliding surface is given on the basis of the system and desired performances. While the law of control is selected with an aim of ensuring the convergence conditions and sliding i.e. the attractivity of commutation surfaces. A comparative analysis of all CSM advantages to those of the classical control (PI) was developed in last stage to highlight the performances of this technique. The various results obtained in simulation allow an evaluation of the robustness and performances of this mode of control variable structure.