Single-chip FPGA implementation of a sensorless speed control IC for permanent magnet synchronous motors

Abstract

This paper presents a single-chip FPGA implementation of a speed sensorless control IC with flux-linkage estimation algorithm for permanent-magnet synchronous motors (PMSM) with sinusoidal flux distribution. By using hierarchical and modular realization strategy, each functional block for the digital sensorless IC is designed as a reusable IP with FPGA implementation. The digital sensorless IC is configurable with its modular blocks and is programmable with its control registers via a serial interface to fit various applications without complicated software programming as realized by using conventional DSP or microcontrollers. The sensorless algorithm implemented uses the incremental values of flux linkage, the normalized back-EMF voltage, and the estimated peak back-EMF value to estimate the incremental rotor position. An internal closed-loop correction mechanism within this algorithm can automatically correct the rotor position estimation drift, which could be resulted by the quantization error, circuit nonlinearities, and sampling noises. An initial rotor position detection scheme with ramping speed control has been developed for startup control. Experimental verification has been carried out on a sensorless spindle motor drive system for DVD applications.