Simulation Analysis of BLDC Motor Three Step Starting

To design high performance sensorless Brushless DC Motor control system, computer simulation technology is adopted to analyze the process of three-step starting process. Firstly, Park transform and Clark transforms are used to build the mathematical model of the first step, pre-position. To avoid striking current, a scheme of pre-position with gradually increasing bus voltage is proposed in the paper, which can make the rotor reach the pre-set position smoothly. In the second step, the acceleration curve of BLDC motor´s rotor plays a key role for the whole starting process. To find out the optimal curve for a BLDC motor control system, the starting process with three types of rotor acceleration curve, linear, exponential and logarithmic, has been studied and analyzed by MATLAB based computer simulation. The simulation results show that the rotor acceleration curves have a great effect for the whole starting process.