Improved Simple I-F Open-Loop Start-up of PMSM Drives Without Speed or Position Sensor

Field-oriented control of PMSM motors without a position or speed sensor is very popular mainly in automotive industry. Many self-sensing/sensorless techniques have been introduced, including saliency-based (high-frequency signal injection) or model-based techniques. This paper focuses on the model-based techniques applications, where an open-loop start-up sequence has to be used. I-F open-loop start-up techniques are discussed. Simulation model and experiments are introduced to explain the open-loop start-up situation in more details. Novel simple current cross-over technique is introduced and tested in concept, indicating positive impact on the start-up reliability especially for low-load or no-load start-up conditions, thus e.g. cooling fan or blower applications.