Abstract: The spaceborne high-precision solar irradiance spectrometer is one of the important instruments for observing and studying the solar irradiance, and the precision of its wavelength scanning mechanism largely determines the accuracy of the spectral measurement results. In order to achieve the required positioning accuracy of the grating, a servo drive system with a voice coil motor as the core is designed. According to the required functions of the system, a drive controller structure scheme of digital signal processing (DSP) and field programmable gate array (FPGA) is designed, then the functions of the system are divided, and the hardware circuits and software programs are designed according to the required functions. The hardware circuits mainly include a motor drive circuit, a high-precision current acquisition circuit, and a position feedback acquisition circuit. The software programs consist of two parts: DSP and FPGA. DSP mainly includes system initialization, external memory interface (EMIF) communication, and three-loop proportional-integral-derivative (PID) calculation. FPGA is mainly used to cooperate with the three-loop PID algorithm of DSP. Its functions mainly include motor driver, analog/digital (A/D) sampling control, coding sampling, and data exchange with DSP. Finally, through simulation verification, experimental test and practical application, the effectiveness of the drive system is verified, the three-loop PID control of the voice coil motor is realized, and at the same time, it is also shown that the actual motor positioning accuracy can meet the design requirements of the drive grating.

Key words: voice coil motor, spectral scanning, digital signal processing, field programmable gate array; proportional-integral-differential controller