Study On Brushless DC Motor Drive System

The permanent magnetic brushless DC motor (BLDCM), which is easy to control and has high power density, so BLDCM is widely used in electric vehicles and family appliances. In this paper, a BUCK circuit added lead before the full bridge which used in BLDCM drive system is proposed, and this drive system is studied. The BUCK leading BLDCM drive system is modeled, and BUCK induct current is used as control variable in current loop. Based on this model, speed open loop control and speed close loop control is studied, and experiments are given to prove the BUCK induct current control is feasible.In BLDCM drive system, torque ripple suppression is needed when BLDCM work at low speed. In this paper, torque ripple is studied, and a new way to suppress torque ripple is proposed based on BUCK leading BLDCM drive system.EMC technique is most important in BLDCM driver, especially in high speed DSP (Digital Signal Processor) control system, several general principles is used in hardware circuit and software.Finally, a DSP (TI TMS320LF2407A) based control system is designed for experimental use, the validities of the proposed methods are strongly supported by the theoretical analysis and experimental results.