The interest in multi-phase machines for high performance applications has been growing in recentrnyears due to their potential advantages over the conventional three-phase machines. Multi-phasernmachines have advantages of fault tolerance and higher power capacity at low voltages comparedrnto three-phase machines. Nine-phase brushless DC motor has additional advantages of high torquerndensity, high efficiency and reduced stator current per phase without the need to increase the phasernvoltage. Sensored control of BLDC machine generally requires measuring the speed and positionrnof rotor by using the sensor. The position sensors make the motor system more complicated,rnmechanically unreliable and expensive. In this thesis, effective sensorless control of nine-phasernBLDC motor using Back-EMF waveform sensing is done. Thus, actual implementation of thernmotor using mathematical model of the machine and nine-phase inverter function based on thernback-EMF sequence generated in the stator windings of nine-phase BLDC motor is simulated withrnthe help of MATLAB Simulink software. rnFor control of the motor PI speed controller is implemented to adjust DC-link voltage based on thernerror between actual speed and desired speed reference. The controlled gain output of the PIrncontroller is fed to the pulse amplitude modulation controlled DC-link voltage source. The resultrnof the controller is investigated and the speed of the motor for different speed level usingrnMATLAB Simulink software. And the result of the simulated speed response of the controller forrndifferent speed has been done and settling time is 0.005sec and rise time is 0.0026sec speedrnresponse controller. Phase voltages of the motor controlled based on the back-EMF waveform rnsequances . switching of nine-phase voltage source inverter controlled has been done efectivelyrnbased on the back-EMF. The simulation results obtained agree with the design objective.