Rapid phase current sampling in a permanent magnet synchronous motor servo system utilizing flexible memory controller bus

<ns4:p>Background The permanent magnet synchronous motor (PMSM) servo system, integral to robots and other high-precision motion control applications, has its performance directly influenced by the current loop in the PMSM servo system. Though the theoretical adjustment time of the current loop can approach the electrical time constant of PMSM in order of magnitude, constraints such as control frequency make the adjustment time significantly larger than this theoretical limit. Methods This paper introduces a PMSM servo system using a flexible memory controller (FMC) bus for rapid phase current sampling. It leverages an independent current sampling module, equipped with an external analog-to-digital (AD) conversion chip for precise sampling of the output phase current of the PMSM. The sampling precision is 16-bit with a range of 0-3V. The sampled signal is preprocessed by a field-programmable gate array (FPGA), with the phase current data finally transmitted to the primary control chip through the FMC bus. Results By implementing this rapid current sampling architecture, we have successfully reduced the current sampling time by 95.4% while maintaining sampling accuracy. This scheme also substantially shortens the microcontroller unit’s (MCU) interrupt response time, potentially enhancing the current loop's control frequency, ultimately increasing the current loop bandwidth to 20kHz. Conclusions In conclusion, the proposed PMSM servo system with rapid current sampling significantly enhances the performance of the current loop. This advancement in sampling efficiency and control frequency offers substantial improvements for high-precision motion control applications, making it a valuable contribution to the field.</ns4:p>