Taking into account attitude stability，microwave scattermeter and microwave radiometer while rotating need to reduce torque ripple. Permanent-magnet motors using vector control technique are used to drive directly both sensors. Restraining cogging torque of motor， eliminating quantization error with fix angle timing，compensating dead time，these are presented. The control system and motor has been simulated by accurate model，results show that the torque ripple is reduced. The orbital attitude speed results are presented to validate this scheme.