• Title/Summary/Keyword: PFC direct drive

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Implementation of the BLDC Motor Drive System using PFC converter and DTC (PFC 컨버터와 DTC를 이용한 BLDC 모터의 구동 시스템 구현)

  • Yang, Oh
    • Journal of the Institute of Electronics Engineers of Korea SC
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    • v.44 no.5
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    • pp.62-70
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    • 2007
  • In this paper, the boost Power Factor Correction(PFC) technique for Direct Torque Control(DTC) of brushless DC motor drive in the constant torque region is implemented on a TMS320F2812DSP. Unlike conventional six-step PWM current control, by properly selecting the inverter voltage space vectors of the two-phase conduction mode from a simple look-up table at a predefined sampling time, the desired quasi-square wave current is obtained, therefore a much faster torque response is achieved compared to conventional current control. Furthermore, to eliminate the low-frequency torque oscillations caused by the non-ideal trapezoidal shape of the actual back-EMF waveform of the BLDC motor, a pre-stored back-EMF versus position look-up table is designed. The duty cycle of the boost converter is determined by a control algorithm based on the input voltage, output voltage which is the dc-link of the BLDC motor drive, and inductor current using average current control method with input voltage feed-forward compensation during each sampling period of the drive system. With the emergence of high-speed digital signal processors(DSPs), both PFC and simple DTC algorithms can be executed during a single sampling period of the BLDC motor drive. In the proposed method, since no PWM algorithm is required for DTC or BLDC motor drive, only one PWM output for the boost converter with 80 kHz switching frequency is used in a TMS320F2812 DSP. The validity and effectiveness of the proposed DTC of BLDC motor drive scheme with PFC are verified through the experimental results. The test results verify that the proposed PFC for DTC of BLDC motor drive improves power factor considerably from 0.77 to as close as 0.9997 with and without load conditions.

Design and Application of PFC Direct Drive Inverter for LCD-TV (LCD-TV용 PFC Direct 구동 인버터의 설계와 응용)

  • Ko, Tae-Seok;Jung, Yong-Joon;Hong, Sung-Soo;Han, Sang-Kyu;Jang, Byung-Jun;Jang, Young-Su;Han, Seung-Ho;Roh, Chung-Wook
    • The Transactions of the Korean Institute of Power Electronics
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    • v.15 no.1
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    • pp.52-59
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    • 2010
  • The conventional CCFL (Cold Cathode Fluorescent Lamp) inverter used in the backlight unit for LCD-TV, composed of the three power stage, can degrade the whole power conversion efficiency. In this paper, a novel scheme to drive the CCFL, composed only of the two power stage without using a dc/dc power stage, is proposed to enhance the whole power conversion efficiency. By adopting the proposed "4-in-1 Transformer", the current balance and the simultaneous ignition among the four CCFL lamp are assured with the one inverter circuit. The proposed scheme features the simple circuit structure, which can save the volume and the cost in the LCD backlight unit. Design considerations are discussed and design procedures are derived. Experimental results of the proposed scheme for 40" LCD-TV are presented to confirm the theoretical analysis.