Research of Drives of Power Amplifiers of Magnetic Levitation Servo Spindle Applied to Micro EDM Based on FPGA

Abstract:

The drives of power amplifiers of magnetic levitation servo spindle applied to micro EDM (Electron discharge machining) based on FPGA (Field programmable gate array) are developed. The drive module that produces the PWM (Pulse width modulation) waves that conform to the requirements of spindle power amplifiers involving three-level half bridge switch power amplifier, three-level full bridge switch power amplifier and motor power amplifier, according to input of action values from magnetic levitation servo spindle controller DSP (Digital signal processor) is designed. Multi-PWM producing algorithm by single timer with multi comparing nodes is proposed. After being applied to control system of magnetic levitation servo spindle, the drives accomplish conversion from DSP action values to PWM waves. The PWMs that drive radial coil current power amplifier have phase difference of 180°. The PWMs that drive axial coil current power amplifier have dead zone time and their wave shapes are complementary. The PWMs that drive the motor power amplifier conform to requirements of power amplifier chip LMD18200. Using FPGA to realize the drive function of spindle power amplifier makes the drive design more flexible, resource distribution of DSP more optimized, the task of algorithms running more centralized, and the drives module gets simpler and more reliable because the phase shift circuit and dead zone circuit are cancelled but the function of phase shift and dead zone is reserved.

• Periodical: Key Engineering Materials (Volume 621)
• Pages: 564-569
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.621.564
• Online since: August 2014
• Authors: Yong Feng Guo*, Song Luo, Ze Bin Ling, Xiao You Zhang
• Keywords: FPGA, Magnetic Levitation Servo Spindle, Micro-Hole EDM, PWM, Three-Level Power Amplifier

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