Patents by Inventor Radu Bojoi

Radu Bojoi has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 11894740
    Abstract: System and method for robust sensorless control of permanent magnet assisted synchronous reluctance (PM-SyR) motor. The system and method includes startup control of a motor with known rotor position/speed, but unknown rotor magnetic polarity of a motor exhibiting rotor magnetic anisotropy or saliency. The system and method includes a rotor characteristic detection method for a PM-SyR motor that detects rotor magnetic polarity based on the variation of the inductance that is caused by the leakage flux paths in the rotor barrier bridges and utilizes the detected rotor magnetic polarity for improved motor startup.
    Type: Grant
    Filed: August 15, 2023
    Date of Patent: February 6, 2024
    Assignee: Wolong Electric Group Ltd.
    Inventors: Radu Bojoi, Zheng Zhang, Dingsheng Lin, Song Chi, Liyang Sun, Weican Yan
  • Patent number: 11239772
    Abstract: Systems and methods for robust control of a sensorless interior permanent magnet synchronous motor during severe operating conditions that causes motor parameter variation. A multi-model flux observer and a dynamic direct flux motor controller act in concert to generate driving commands. The flux observer transitions between providing flux-based rotor characteristic estimates based on different motor models. DHFI filtered currents can be utilized to obtain flux-based characteristic estimates using a motor magnetic model that are unaffected by motor parameter variations. The multi-model flux observer can be configured to transition between suitable estimation methods to reduce, minimize, or eliminate the effects of motor parameter variations.
    Type: Grant
    Filed: April 1, 2021
    Date of Patent: February 1, 2022
    Assignee: Wolong Electric Group Co. Ltd.
    Inventors: Radu Bojoi, Zheng Zhang, Ze Jiang
  • Patent number: 10819264
    Abstract: A robust starting system and method for an interior permanent magnet synchronous motor, suitable for commercial fan and blower drive applications. A comprehensive starting control process is provided that utilizes control flags to implement closed-loop control accounting for any pre-existing rotor movement, controlling the motor speed from an initial speed to a destination speed. A universal dqController provides selective configurability for collecting information regarding the initial state of the motor, as well as starting and operational motor control. Dynamic high frequency injection enables the use of HFI outside the normal standstill motor speeds by intelligently decoupling the high frequency and rotor movement portions of the stator current response.
    Type: Grant
    Filed: August 4, 2020
    Date of Patent: October 27, 2020
    Assignee: Wolong Electric Group Co. Ltd.
    Inventors: Radu Bojoi, Zheng Zhang, Ze Jiang
  • Patent number: 10784805
    Abstract: A system and method for robust control of a sensorless interior permanent magnet synchronous motor. The system and method includes rotor characteristic detection to detect or estimate rotor position, rotor speed, and rotor magnetic polarity based on rotor magnetic anisotropy or saliency. Detecting rotor magnetic polarity allows determination of orientation of the rotor and, for a rotor in motion, direction of travel. A high frequency injection enables rotor position detection and an alternating carrier method enables detection of rotor magnetic polarity. The system and method can also include closed loop startup control from a standstill condition following detection of rotor characteristics.
    Type: Grant
    Filed: February 19, 2020
    Date of Patent: September 22, 2020
    Assignee: Wolong Electric Group Co. Ltd.
    Inventors: Radu Bojoi, Zheng Zhang, Ze Jiang