| Title |
DC-Link Voltage Unbalancing Compensation of Four-Switch Inverter for Three-Phase BLDC Motor Drive |
| Authors |
박상훈(Park, Sang-Hoon) ; 윤용호(Yoon, Yong-Ho) ; 이병국(Lee, Byoung-Kuk) ; 이수원(Lee, Su-Won) ; 원충연(Won, Chung-Yuen) |
| Keywords |
BLDC ; 4-Switch Inverter ; Half-Bridge Boost Converter ; Voltage Compensation ; Feedforward Controller |
| Abstract |
In this paper, a control algorithm for DC-Link voltage unbalancing compensation of a four-switch inverter for a three-phase BLDC motor drive is proposed. Compared with a conventional six-switch inverter, the split source of the four-switch inverter can be obtained by splitting DC-link capacitor into two capacitors to drive the three phase BLDC motor. The voltages across each of two capacitors are not always equal in steady state because of the unbalance in the impedance of the DC-link capacitors C_1 and C_2 or the variable current flowed into the capacitor's neutral point in motor control. Despite the unbalance, if the BLDC motor may be run for a long time the voltage across one of the capacitors is more increased. So the unbalance in the capacitors voltages will be accelerated. As a result, The current ripple and torque ripple is increased due to the fluctuation of input current which flows into 3-phase BLDC motor. According to that, the vibration of motor will be increased and the whole system will be instable. This paper presents a control algorithm for DC-Link voltage unbalancing compensation. The sampling from the voltages across each of two capacitors is used to perform the voltage control of DC-Link by using the feedforward controller. |