Novel Architecture of a Mixed-Mode Sensorless Control IC for BLDC Motors with Wide Speed Ranges

摘要: This paper presents a novel sensorless control architecture, which is dedicated for mixed-mode IC implementation, many low-cost applications of brushless DC (BLDC) motors over wide speed ranges. In order to measure the back-EMFs whole PWM switching cycle from low full duty ratio, hybrid back-EMF zero-crossing detection circuit presented sense and compare without heavy filtering during both PWM-on PWM-off states. And detected zero-crossings can be synchronously sampled with an internal high-frequency signal, considers turn-on turn-off delays power transistors, reducing latency between real ones achieve operations. Besides, auto-detection technique adjustable level detector also proposed improve robustness detecting free-wheeling diode conducting period at high speeds heave-load Furthermore, smooth startup operation, initial rotor position estimation strategy by measuring rise time dc-link current instead its peak current. Lower sensitivity motor parameters obtained method, maximum limited angle detection. Neither micro unit (MCU) nor analog-to-digital converters (ADCs) are required architecture but high-performance solutions. The evaluated FPGA-based system.