Chaos of power electronic systems and electric motor drives were introduced a few decades ago and follow with numerous of research literature. However, chaos of permanent magnet synchronous motors, in particular, seems not receive enough deserved interest. Considering this fact, this paper designs a linear quadratic regulator (LQR) to suppress chaotic behaviors of PMSMs. The stability and robustness properties of the proposed LQR are fully presented. It should be noted that this is the first time the robustness of LQR for chaos suppression of PMSMs are discussed. Due to its robustness properties, the proposed LQR scheme not only can eliminate the chaos but also provide better performances than conventional methods. Simulations results under various scenarios prove the superiority of the proposed control technique over conventional controllers.