Patents by Inventor Shizhong Ji

Shizhong Ji 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: 11955915
    Abstract: The present disclosure provides a variable-frequency compressor with adaptive heating power control and a method for operating the same. According to an embodiment of the present disclosure, the variable-frequency compressor includes: a compression unit, for compressing a medium entering the variable-frequency compressor; a motor, including a stator and a rotor, for driving the compression unit; and a controller, configured to adaptively control a heating power of a winding of the stator according to information of the variable-frequency compressor.
    Type: Grant
    Filed: December 14, 2021
    Date of Patent: April 9, 2024
    Assignee: DANFOSS (TIANJIN) LTD.
    Inventors: Shizhong Ji, Wanzhen Liu, Yingke Sun, Li Yao
  • Publication number: 20240056010
    Abstract: A method and apparatus for detecting an initial position of a rotor of a motor includes: switching on or off respective switches in respective connecting branches connected to respective phase windings of the motor so as to obtain different switch state combinations capable of supporting different phase states of the motor, wherein the different switch state combinations support inputting voltages for different phases to the motor; for each switch state combination, injecting a voltage and recording a start time; monitoring respective phase currents of the motor, including: stopping the injecting of the voltage in response to determining that at least one of the respective phase currents is greater than a current threshold during the injecting of the voltage; and recording an end time in response to determining that the respective phase currents are all attenuated to zero after stopping the injecting of the voltage; and calculating a time difference between the end time and the start time; and determining the
    Type: Application
    Filed: August 14, 2023
    Publication date: February 15, 2024
    Inventors: Shizhong JI, Wanzhen LIU, Li YAO
  • Patent number: 11699969
    Abstract: A compressor and a control method thereof are provided. The compressor includes a motor with a rotor of a permanent magnet. According to embodiments, the method of controlling the compressor includes: applying a detection current to the motor in response to a command of starting the compressor; detecting whether there is demagnetization of the permanent magnet of the rotor according to a response of the motor to the applied detection current; resetting an operating parameter of the compressor if there is the demagnetization; and starting the compressor according to the reset operating parameters. According to embodiments of the present disclosure, when the compressor is to be started, demagnetization is detected first, and the operating parameter are set accordingly, so as to suppress or avoid performance degeneration due to the demagnetization.
    Type: Grant
    Filed: July 29, 2020
    Date of Patent: July 11, 2023
    Assignee: Danfoss (Tianjin) Ltd.
    Inventors: Shizhong Ji, Li Yao, Wanzhen Liu
  • Publication number: 20230119389
    Abstract: A rotor for an interior permanent magnet motor, an interior permanent magnet motor, and a compressor includes a rotor core, a plurality of U-shaped permanent magnet accommodating grooves, a plurality of first air grooves, and a plurality of first recesses, wherein the plurality of U-shaped permanent magnet accommodating grooves are arranged inside the rotor core at intervals; the plurality of first air grooves are provided outside the ends of the U-shaped permanent magnet accommodating grooves; and each first air groove is located on an extension line of the end of the corresponding U-shaped permanent magnet accommodating groove and is close to the outer contour of the rotor so as to form a plurality of first magnetic isolation bridges.
    Type: Application
    Filed: February 23, 2021
    Publication date: April 20, 2023
    Inventors: Wanzhen LIU, Yan LIN, Guangqiang LIU, Zhenyu WANG, Meng WANG, Shizhong JI, Li YAO
  • Publication number: 20220186730
    Abstract: The present disclosure provides a variable-frequency compressor with adaptive heating power control and a method for operating the same. According to an embodiment of the present disclosure, the variable-frequency compressor includes: a compression unit, for compressing a medium entering the variable-frequency compressor; a motor, including a stator and a rotor, for driving the compression unit; and a controller, configured to adaptively control a heating power of a winding of the stator according to information of the variable-frequency compressor.
    Type: Application
    Filed: December 14, 2021
    Publication date: June 16, 2022
    Inventors: Shizhong Ji, Wanzhen Liu, Yingke Sun, Li Yao
  • Patent number: 11133760
    Abstract: Embodiments of the present invention provide a method for controlling compressor braking, a frequency converter and a variable speed compressor. The method includes steps of: determining to brake a compressor, wherein a brake circuit includes three switching units and the three switching units are respectively electrically connected to three phases of windings of a motor of the compressor; actuating two of the three switching units to short-circuit two phases of windings of the motor. The two phases of windings of the motor are short-circuited by controlling the three switching units to generate braking torque, such that the compressor is braked without introducing a DC voltage, and thus the braking energy consumption is reduced. Besides, by turning on only two switches at a time, the switching abrasion is reduced, and the overall service life of the three switching units is effectively improved.
    Type: Grant
    Filed: December 3, 2019
    Date of Patent: September 28, 2021
    Assignee: Danfoss (Tianjin) Ltd.
    Inventors: Shizhong Ji, Li Yao, Yingke Sun, Qingyue Meng
  • Publication number: 20210058019
    Abstract: A compressor and a control method thereof are provided. The compressor includes a motor with a rotor of a permanent magnet. According to embodiments, the method of controlling the compressor includes: applying a detection current to the motor in response to a command of starting the compressor; detecting whether there is demagnetization of the permanent magnet of the rotor according to a response of the motor to the applied detection current; resetting an operating parameter of the compressor if there is the demagnetization; and starting the compressor according to the reset operating parameters. According to embodiments of the present disclosure, when the compressor is to be started, demagnetization is detected first, and the operating parameter are set accordingly, so as to suppress or avoid performance degeneration due to the demagnetization.
    Type: Application
    Filed: July 29, 2020
    Publication date: February 25, 2021
    Inventors: Shizhong Ji, Li Yao, Wanzhen Liu
  • Publication number: 20210036651
    Abstract: The present disclosure provides a parameter control system for a motor, comprising: a current acquisition circuit connected to the motor, so as to acquire a current output by the motor; an arithmetic processor configured to determine whether to adjust a parameter of the motor according to the current acquired, and generate a new parameter when it is determined to adjust the parameter of the motor; and an output circuit configured to output the new parameter generated by the arithmetic processor to a control device of the motor. The present disclosure also provides a motor including the parameter control system.
    Type: Application
    Filed: July 29, 2020
    Publication date: February 4, 2021
    Inventors: Shizhong Ji, Li Yao, Yingke Sun, Qingyue Meng
  • Publication number: 20200186057
    Abstract: Embodiments of the present invention provide a method for controlling compressor braking, a frequency converter and a variable speed compressor. The method includes steps of: determining to brake a compressor, wherein a brake circuit includes three switching units and the three switching units are respectively electrically connected to three phases of windings of a motor of the compressor; actuating two of the three switching units to short-circuit two phases of windings of the motor. The two phases of windings of the motor are short-circuited by controlling the three switching units to generate braking torque, such that the compressor is braked without introducing a DC voltage, and thus the braking energy consumption is reduced. Besides, by turning on only two switches at a time, the switching abrasion is reduced, and the overall service life of the three switching units is effectively improved.
    Type: Application
    Filed: December 3, 2019
    Publication date: June 11, 2020
    Inventors: Shizhong Ji, Li Yao, Yingke Sun, Qingyue Meng