Abstract: In many applications such as electrical vehicle and computer numerical control machine,induction motor（IM） needs large speed range operation with constant output power.A new current and voltage trajectories control scheme for the field weakening operation of induction motor drive was presented.The proposed scheme allows the motor to exploit the maximum torque capability in the whole speed range with the constraints of maximum voltage and current of the motor and inverter.In the proposed control algorithm the lookup table is not required for currents references obtaining,which reduces the dependence on the motor parameters.The smooth transition between maximum torque per ampere（MTPA） and field weakening regions is implemented according to the integration of the time of zero voltage vector in SVPWM method.The validity of the proposed field weakening technique is validated by computer simulations and experimental tests with a 5.5?kW induction motor drive system.