A new technique for high performance and robust speed control of permanent magnet synchronous motor (PMSM) using a mixed non-linear H∞ and Sliding Mode Control (SMC) is applied. In spite of non-linear modes, motor parameters variation and uncertainty of load torque, non-linear robust techniques introduce a precise speed control. Since the load torque is an external disturbance and its variation and type is not generally available, H∞ technique is a suitable approach to minimize its influence on the output. However, motor parameters variations throw away the response from H∞ response and influence its response, therefore SMC technique is used to conduct the response towards H∞ response. Combination of these two techniques gives a suitable technique to robust speed control of PMSM.