A novel digital controller for microstepping stepper motor drive using FPGA for Solar Array Drive Assembly in satellites-A comparison With alternative schemes

Solar Array Drive Assembly (SADA) requires high precision in positioning of the photovoltaic panels, which can be attained through the use of stepper motors. In this paper, a digital controller for micro-stepping drive of stepper motor using Look up Table(LUT) approach is proposed and is compared to the conventional full-step methodology and the Pulse Width Modulation (PWM) technique used for microstepping. The comparison is done on the basis of (I) Switching frequency of the drivers, (II) The hardware complexity involved and (III) Synthesis report-Utilization of number of gates. Although the conventional full-step methodology is easy to implement and reliable, it severely limits in terms of resolution, ripple and mid-frequency resonance. In case of PWM technique for micros-tepping the above mentioned problems are well settled at the cost of high switching frequency. The proposed methodology accounts the problem of resolution, mid-frequency resonance and switching frequency at the cost of the increased external hardware complexity and processor requirements. The design is implemented in Xilinx ISE. Results are presented to show the substantial advantages of the proposed methodology and to bring about comparison with other mentioned methodologies.