Mobile QR Code QR CODE : The Transactions of the Korean Institute of Electrical Engineers
Title A Study on PWM Techniques for Driving PMSM Inverter by 150-Degree Conduction Method
Authors 이승용(Seung-Yong Lee) ; 윤덕용(Duck-Yong Yoon)
Page pp.285-295
ISSN 1975-8359
Keywords PMSM ; BLDCM ; Inverter ; PWM ; 150-degree conduction method ; Six-switch asymmetrical discontinuous PWM ; SADPWM
Abstract In this paper, we have studied the PWM techniques for operating inverter for PMSM with 150-degree conduction method. In the conventional upper switch PWM technique, only three upper switches perform PWM switching, so they are very much used and have a large switching loss compared to three lower switches. And torque ripple occurs due to circulating current flowing by difference of back-EMF generated between two stator windings of motor in PWM switching section of inverter where one upper switch for PWM switching is turned off and two lower switches are turned on when motor operate in high speed and at light load. So, we propose a six-switch asymmetrical discontinuous PWM(SADPWM) techniques in order to improve the disadvantages of upper switch PWM technique. The proposed PWM technique can be used as SADPWM1 and SADPWM2 technique by changing the order of PWM switching sections. Computer simulations and experiments were carried out for SPMSM of 750[W] class. Using proposed PWM technique, upper and lower switches have the same PWM switching operation. And circulating current did not flow in stator winding of motor under operating condition in which motor operate at high speed 3000[rpm] and at light load. In addition, it is confirmed that loss of switching elements in inverter is reduced at light load and torque ripple of motor does not occur. Also, in SADPWM2 technique freewheeling current does not flow in the non-conduction section and less operation loss results in comparison to SADPWM1 technique. Because proposed PWM technique can be realized only by software modification in conventional upper switch PWM technique, it can be widely used in applications using 120-degree conduction method. Also, it can be applied to inverter for BLDCM.