TY - JOUR
T1 - A Novel Flexible Capacitor Voltage Control Strategy for Variable-Speed Drives with Modular Multilevel Converters
AU - Tai, Bingyong
AU - Gao, Congzhe
AU - Liu, Xiangdong
AU - Chen, Zhen
N1 - Publisher Copyright:
© 2016 IEEE.
PY - 2017/1
Y1 - 2017/1
N2 - Modular multilevel converter (MMC) is very popular in medium-voltage applications, such as high-voltage direct current transmission, static Var generator, and motor drives. The arm capacitor voltage of MMC is usually constant and the output voltage is adjusted by regulating the pulse width modulation (PWM) index for switches in previous studies. In this paper, a novel flexible capacitor voltage control strategy for MMC as motor drives was proposed, with which the arm capacitor voltage was controlled flexibly according to the motor speed, by regulating the dc component and ac component of the PWM reference signal, and unsymmetrical control was used for the control of the upper arm and the lower arm in MMC. With the proposed control strategy, the circuit efficiency and the precision of the output voltage of the converter could be improved when the motor speed was low, and di/dt and d v/dt of the motor windings could be decreased. These proposals were implemented on a laboratory prototype, and experiments were carried out. The validity of the control strategy under both steady and dynamic states was verified.
AB - Modular multilevel converter (MMC) is very popular in medium-voltage applications, such as high-voltage direct current transmission, static Var generator, and motor drives. The arm capacitor voltage of MMC is usually constant and the output voltage is adjusted by regulating the pulse width modulation (PWM) index for switches in previous studies. In this paper, a novel flexible capacitor voltage control strategy for MMC as motor drives was proposed, with which the arm capacitor voltage was controlled flexibly according to the motor speed, by regulating the dc component and ac component of the PWM reference signal, and unsymmetrical control was used for the control of the upper arm and the lower arm in MMC. With the proposed control strategy, the circuit efficiency and the precision of the output voltage of the converter could be improved when the motor speed was low, and di/dt and d v/dt of the motor windings could be decreased. These proposals were implemented on a laboratory prototype, and experiments were carried out. The validity of the control strategy under both steady and dynamic states was verified.
KW - Carrier phase-shifted modulation
KW - flexible capacitor voltage control
KW - modular multilevel converter
KW - motor drive
UR - http://www.scopus.com/inward/record.url?scp=84988698264&partnerID=8YFLogxK
U2 - 10.1109/TPEL.2016.2535463
DO - 10.1109/TPEL.2016.2535463
M3 - Article
AN - SCOPUS:84988698264
SN - 0885-8993
VL - 32
SP - 128
EP - 141
JO - IEEE Transactions on Power Electronics
JF - IEEE Transactions on Power Electronics
IS - 1
M1 - 7422109
ER -