Patents by Inventor Guohai Liu

Guohai Liu 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: 12081147
    Abstract: The present disclosure provides a method for reducing the electromagnetic vibration of a fractional slot concentrated winding (FSCW) permanent magnet (PM) motor, which provides a guidance for the low vibration design of FSCW PM motor. The implementation of the method includes: Based on Nyquist Shannon sampling theorem, the modulation effect of electromagnetic force in the air gap is obtained, and the electromagnetic force component that contributes the most to the electromagnetic vibration of the FSCW PM motor is determined. The equivalent analytical model of PM flux density is established to obtain the phase relationship between different flux density harmonics. According to Maxwell stress equation, the internal relationship between each order of flux density harmonics and electromagnetic force harmonics is obtained. A new magnet structure of the PM motor is designed, and specific flux density harmonics are injected to reduce the electromagnetic force and electromagnetic vibration of the FSCW PM motor.
    Type: Grant
    Filed: March 2, 2021
    Date of Patent: September 3, 2024
    Assignee: Jiangsu University
    Inventors: Wenxiang Zhao, Shengdao Zhu, Guohai Liu, Jinghua Ji
  • Publication number: 20240240861
    Abstract: A food dehydrator includes a housing defining a drying chamber therein with an upper wall of the housing delimiting the drying chamber in a vertical upward direction, a door moveably coupled to the housing and configured to selectively cover a front opening of the housing providing access to the drying chamber, and an upper window provided in the upper wall of the housing at a position above the drying chamber. The upper window is formed of a transparent or semi-transparent material providing visual access to the drying chamber within the housing. A recessed area is formed in the upper wall of the housing and is configured to removably receive a shelf or tray therein, and the shelf or tray is further configured for removable reception within the drying chamber of the housing and is configured to support a food item thereon during a dehydrating process.
    Type: Application
    Filed: August 21, 2023
    Publication date: July 18, 2024
    Inventors: Rong Liu, Thomas P. McLaughlin, Guohai Wu
  • Publication number: 20240106360
    Abstract: The present disclosure provides a method for reducing the electromagnetic vibration of a fractional slot concentrated winding (FSCW) permanent magnet (PM) motor, which provides a guidance for the low vibration design of FSCW PM motor. The implementation of the method includes: Based on Nyquist Shannon sampling theorem, the modulation effect of electromagnetic force in the air gap is obtained, and the electromagnetic force component that contributes the most to the electromagnetic vibration of the FSCW PM motor is determined. The equivalent analytical model of PM flux density is established to obtain the phase relationship between different flux density harmonics. According to Maxwell stress equation, the internal relationship between each order of flux density harmonics and electromagnetic force harmonics is obtained. A new magnet structure of the PM motor is designed, and specific flux density harmonics are injected to reduce the electromagnetic force and electromagnetic vibration of the FSCW PM motor.
    Type: Application
    Filed: March 2, 2021
    Publication date: March 28, 2024
    Applicant: Jiangsu University
    Inventors: Wenxiang ZHAO, Shengdao ZHU, Guohai LIU, Jinghua JI
  • Patent number: 11611307
    Abstract: A short-circuit fault-tolerant control method based on deadbeat current tracking for a five-phase permanent magnet motor with a sinusoidal back-electromotive force or a trapezoidal back-electromotive force (EMF) is provided. By fully utilizing a third harmonic space of a five-phase permanent magnet motor in a fault state, the method proposes a fault-tolerant control strategy for a five-phase permanent magnet motor with a sinusoidal back-EMF or a trapezoidal back-EMF in case of a single-phase short-circuit fault. The method enables the five-phase permanent magnet motor to make full use of the third harmonic space during fault-tolerant operation, thereby improving the torque output of the motor in a fault state and improving the fault-tolerant operation efficiency of the motor. The method achieves desirable fault-tolerant performance and dynamic response of the motor, and expands the speed range of the motor during fault-tolerant operation.
    Type: Grant
    Filed: December 7, 2020
    Date of Patent: March 21, 2023
    Assignee: JIANGSU UNIVERSITY
    Inventors: Qian Chen, Yuhang Xia, Licheng Gu, Wenxiang Zhao, Guohai Liu
  • Patent number: 11522400
    Abstract: The present invention relates to a fault-tolerant modular permanent magnet assisted synchronous reluctance motor (PMaSynRM) and provides a modular winding connection method. The modular winding connection is to change the positions of inlet and outlet coils based on the slot electrical potential star vectogram. Then, each module has a separate set of winding and the left and right relative distribution will be adopted on the winding connection. The invention has the advantages of modularization in structure, high independence between the modules, effectively avoiding overlapping of magnetic lines between the modules, and improving fault tolerance and reliability of the motor. The invention has the advantages of modularization in structure, high independence between the modules, magnetic decoupling between the modules, and improvement of fault tolerance and reliability of the motor.
    Type: Grant
    Filed: January 4, 2019
    Date of Patent: December 6, 2022
    Assignee: Jiangsu University
    Inventors: Guohai Liu, Meimei Xu, Wenxiang Zhao, Jinghua Ji, Qian Chen, Zhijian Ling
  • Publication number: 20220368269
    Abstract: A short-circuit fault-tolerant control method based on deadbeat current tracking for a five-phase permanent magnet motor with a sinusoidal back-electromotive force or a trapezoidal back-electromotive force (EMF) is provided. By fully utilizing a third harmonic space of a five-phase permanent magnet motor in a fault state, the method proposes a fault-tolerant control strategy for a five-phase permanent magnet motor with a sinusoidal back-EMF or a trapezoidal back-EMF in case of a single-phase short-circuit fault. The method enables the five-phase permanent magnet motor to make full use of the third harmonic space during fault-tolerant operation, thereby improving the torque output of the motor in a fault state and improving the fault-tolerant operation efficiency of the motor. The method achieves desirable fault-tolerant performance and dynamic response of the motor, and expands the speed range of the motor during fault-tolerant operation.
    Type: Application
    Filed: December 7, 2020
    Publication date: November 17, 2022
    Applicant: JIANGSU UNIVERSITY
    Inventors: Qian CHEN, Yuhang XIA, Licheng GU, Wenxiang ZHAO, Guohai LIU
  • Publication number: 20210359565
    Abstract: The present invention relates to a fault-tolerant modular permanent magnet assisted synchronous reluctance motor (PMaSynRM) and provides a modular winding connection method. The modular winding connection is to change the positions of inlet and outlet coils based on the slot electrical potential star vectogram. Then, each module has a separate set of winding and the left and right relative distribution will be adopted on the winding connection. The invention has the advantages of modularization in structure, high independence between the modules, effectively avoiding overlapping of magnetic lines between the modules, and improving fault tolerance and reliability of the motor. The invention has the advantages of modularization in structure, high independence between the modules, magnetic decoupling between the modules, and improvement of fault tolerance and reliability of the motor.
    Type: Application
    Filed: January 4, 2019
    Publication date: November 18, 2021
    Applicant: JIANGSU UNIVERSITY
    Inventors: Guohai LIU, Meimei XU, Wenxiang ZHAO, Jinghua JI, Qian CHEN, Zhijian LING
  • Patent number: 11159113
    Abstract: In the fault-tolerant direct thrust-force control (FT-DTC) method, the generalized Clarke transform matrix and its inverse matrix are derived according to the fault-tolerant phase currents. The stator fluxes in ?-? plane are deduced based on these. Based on the requirement of circular stator flux trajectory, virtual stator fluxes are defined, and then compensatory voltages in the ?-? plane are obtained. Actual stator voltages in the ?-? plane are calculated by modulation function of voltage source inverter. Combining with the compensatory voltages, the actual stator voltages and the stator currents, the virtual stator fluxes and the thrust-force are estimated by the flux and thrust-force observers. The thrust-force reference, the stator flux amplitude reference, the observed thrust-force and virtual stator flux are applied to predict virtual stator voltage references.
    Type: Grant
    Filed: January 31, 2018
    Date of Patent: October 26, 2021
    Assignee: JIANGSU UNIVERSITY
    Inventors: Huawei Zhou, Cheng Zhou, Guohai Liu, Duo Zhang
  • Publication number: 20210167652
    Abstract: This invention proposes a method to regulate high efficiency region of permanent magnet motor. The internal relationship between the point with maximum efficiency and the points around it is firstly revealed. Then, the optimal combination of copper loss, iron loss and permanent magnet eddy-current loss is presented when maximum efficiency point moves toward different directions. Hence, the method for regulating high efficiency region can be obtained. This method can be suitable for any type of permanent magnet motors, which can adjust high efficiency region to the dense working point area of the motor under different operating conditions according to design requirements. If this method is used into electric vehicle, it can combine the high efficiency region with the electric vehicle driving cycle to reduce energy consumption and enhance the life mileage of electric vehicle effectively.
    Type: Application
    Filed: June 30, 2017
    Publication date: June 3, 2021
    Inventors: Qian CHEN, Xun FAN, Guohai LIU, Wenxiang ZHAO, Jinghua JI, Gaohong XU
  • Publication number: 20210067077
    Abstract: In the fault-tolerant direct thrust-force control (FT-DTC) method, the generalized Clarke transform matrix and its inverse matrix are derived according to the fault-tolerant phase currents. The stator fluxes in ?-? plane are deduced based on these. Based on the requirement of circular stator flux trajectory, virtual stator fluxes are defined, and then compensatory voltages in the ?-? plane are obtained. Actual stator voltages in the ?-? plane are calculated by modulation function of voltage source inverter. Combining with the compensatory voltages, the actual stator voltages and the stator currents, the virtual stator fluxes and the thrust-force are estimated by the flux and thrust-force observers. The thrust-force reference, the stator flux amplitude reference, the observed thrust-force and virtual stator flux are applied to predict virtual stator voltage references.
    Type: Application
    Filed: January 31, 2018
    Publication date: March 4, 2021
    Applicant: JIANGSU UNIVERSITY
    Inventors: Huawei ZHOU, Cheng ZHOU, Guohai LIU, Duo ZHANG
  • Patent number: 10700562
    Abstract: An electric motor includes 3 stators and 1 rotor which employs distributed winding. The axial magnetic circuit generates permanent magnet torque, while the radial magnetic circuit generates reluctance torque. By decoupling the axial and radial magnetic circuits, the separation and the independent control of the permanent magnet torque and the reluctance torque are realized. Each stator and rotor can be processed independently, and modular installation can be processed, thereby reducing the difficulty of motor processing.
    Type: Grant
    Filed: March 16, 2016
    Date of Patent: June 30, 2020
    Assignee: JIANGSU UNIVERSITY
    Inventors: Qian Chen, Wenxiang Zhao, Guohai Liu, Jinghua Ji, Gaohong Xu, Zhipeng Lin
  • Patent number: 10574164
    Abstract: The invention proposes a fault-tolerant field-oriented control method of five-phase interior permanent-magnet fault-tolerant linear motor (IPM-FTLM) with two nonadjacent short-circuit phase faults. Firstly, the extended Clark transformation matrix can be obtained according to the principle that magnetic motive force (MMF) keeps constant before and after the two-phase open-circuit faults, the constraint that the sum of healthy phase currents is zero and the adjacent two-phase current amplitude is equal. The back electric motive force (EMF) can be estimated by the transposed matrix. The nonlinear strong coupling system becomes the first-order inertia system when using the internal mode controller, the first-order inertia feed-forward voltage compensator and back-EMF observer, as the motor is with fault.
    Type: Grant
    Filed: August 17, 2016
    Date of Patent: February 25, 2020
    Assignee: Jiangsu University
    Inventors: Huawei Zhou, Guohai Liu, Jinghua Ji, Wenxiang Zhao, Qian Chen, Long Chen
  • Patent number: 10541595
    Abstract: Disclosed is a double-stator linear vernier permanent magnet (DS-LVPM) motor and method to increase the magnetic field modulation effect. The motor contains a primary, and first and second secondaries on both sides of the primary, spaced by an air gap. The motor secondary includes modulation teeth. The primary is bilaterally symmetrical, and permanent magnets (PM) are embedded in the yoke of the primary core elements. The design solves the inherent problem of flux leakage at the end of PMs for conventional VPM motors, so as to improve utilization of PMs, thereby increasing thrust density of the motors. Additionally, the motor secondaries are laminated by silicon steel sheet, which saves PM material and significantly reduces cost for linear long stroke applications. By adjusting PM structure parameters, the design can use finite element method (FEM) to calculate repeatedly to get PM structure parameters corresponding to maximum electromotive force (EMF).
    Type: Grant
    Filed: December 9, 2015
    Date of Patent: January 21, 2020
    Assignee: JIANGSU UNIVERSITY
    Inventors: Wenxiang Zhao, Jian Zhu, Jinghua Ji, Guohai Liu, Zhengmeng Liu, Qian Chen, Jinwei Chen
  • Patent number: 10530278
    Abstract: A method named as Magnet Shifting to reduce torque ripple of permanent magnet synchronous motor is disclosed. A way of reasonably choosing the repeating unit of magnetic pole, the shifting ways and the shifting angle calculation of the first and second magnet shifting is described, which are carried on the repeating unit of magnetic poles individually or repeatedly to improve the performance of the motor. The method can be applied to surface, surface-inset and inner-embedded permanent magnet motors, which can reduce torque ripple caused by different torque components, including cogging torque, reluctance torque or permanent magnet torque. It also can quickly calculate the shifting angle of the magnetic pole by choosing repeating unit reasonably. Magnet shifting can effectively enhance the sinusoidal degree of back electrodynamic force (back-EMF) waveform, where the repeating units can offset the torque ripple between the maximum and the minimum value to reduce the different torque harmonics.
    Type: Grant
    Filed: February 6, 2017
    Date of Patent: January 7, 2020
    Assignee: JIANGSU UNIVERSITY
    Inventors: Guohai Liu, Xinxin Du, Wenxiang Zhao, Qian Chen, Deshui Hu
  • Publication number: 20190393811
    Abstract: A method named as Magnet Shifting to reduce torque ripple of permanent magnet synchronous motor is disclosed. A way of reasonably choosing the repeating unit of magnetic pole, the shifting ways and the shifting angle calculation of the first and second magnet shifting is described, which are carried on the repeating unit of magnetic poles individually or repeatedly to improve the performance of the motor. The method can be applied to surface, surface-inset and inner-embedded permanent magnet motors, which can reduce torque ripple caused by different torque components, including cogging torque, reluctance torque or permanent magnet torque. It also can quickly calculate the shifting angle of the magnetic pole by choosing repeating unit reasonably. Magnet shifting can effectively enhance the sinusoidal degree of back electrodynamic force (back-EMF) waveform, where the repeating units can offset the torque ripple between the maximum and the minimum value to reduce the different torque harmonics.
    Type: Application
    Filed: February 6, 2017
    Publication date: December 26, 2019
    Applicant: Jiangsu University
    Inventors: Guohai Liu, Xinxin Du, Wenxiang Zhao, Qian Chen, Deshui Hu
  • Patent number: 10505483
    Abstract: Disclosed are fault-tolerant permanent-magnet vernier cylindrical electric motors with an electromagnetic suspension and a fault-tolerant vector control method for a short circuit of two adjacent phases. The fault-tolerant permanent-magnet vernier cylindrical electric motor with an electromagnetic suspension and the fault-tolerant vector control method for a short circuit of two adjacent phases suppress motor thrust ripples caused by a fault of two adjacent phases of an electric motor. The dynamic performance and the steady-state performance thereof are consistent with those under a normal state, and the switching frequency of a voltage source inverter is constant.
    Type: Grant
    Filed: January 25, 2019
    Date of Patent: December 10, 2019
    Assignee: JIANGSU UNIVERSITY
    Inventors: Huawei Zhou, Zhen Lu, Guohai Liu, Wenxiang Zhao, Jinghua Ji, Long Chen
  • Publication number: 20190229666
    Abstract: Disclosed are fault-tolerant permanent-magnet vernier cylindrical electric motors with an electromagnetic suspension and a fault-tolerant vector control method for a short circuit of two adjacent phases. The fault-tolerant permanent-magnet vernier cylindrical electric motor with an electromagnetic suspension and the fault-tolerant vector control method for a short circuit of two adjacent phases suppress motor thrust ripples caused by a fault of two adjacent phases of an electric motor. The dynamic performance and the steady-state performance thereof are consistent with those under a normal state, and the switching frequency of a voltage source inverter is constant.
    Type: Application
    Filed: January 25, 2019
    Publication date: July 25, 2019
    Inventors: Huawei Zhou, Zhen Lu, Guohai Liu, Wenxiang Zhao, Jinghua Ji, Long Chen
  • Patent number: 10309727
    Abstract: A method and apparatus for cooling hot gas streams in the temperature range 800° C. to 1600° C. using multi-stage circulating fluid bed (CFB) coolers is disclosed. The invention relates to cooling the hot syngas from coal gasifiers in which the hot syngas entrains substances that foul, erode and corrode heat transfer surfaces upon contact in conventional coolers. The hot syngas is cooled by extracting and indirectly transferring heat to heat transfer surfaces with circulating inert solid particles in CFB syngas coolers. The CFB syngas coolers are staged to facilitate generation of steam at multiple conditions and hot boiler feed water that are necessary for power generation in an IGCC process. The multi-stage syngas cooler can include internally circulating fluid bed coolers, externally circulating fluid bed coolers and hybrid coolers that incorporate features of both internally and externally circulating fluid bed coolers.
    Type: Grant
    Filed: September 22, 2016
    Date of Patent: June 4, 2019
    Assignee: Southern Company
    Inventors: Guohai Liu, Pannalal Vimalchand, Xiaofeng Guan, WanWang Peng
  • Publication number: 20190006973
    Abstract: The invention proposes a fault-tolerant field-oriented control method of five-phase interior permanent-magnet fault-tolerant linear motor (IPM-FTLM) with two nonadjacent short-circuit phase faults. Firstly, the extended Clark transformation matrix can be obtained according to the principle that magnetic motive force (MMF) keeps constant before and after the two-phase open-circuit faults, the constraint that the sum of healthy phase currents is zero and the adjacent two-phase current amplitude is equal. The back electric motive force (EMF) can be estimated by the transposed matrix. The nonlinear strong coupling system becomes the first-order inertia system when using the internal mode controller, the first-order inertia feed-forward voltage compensator and back-EMF observer, as the motor is with fault.
    Type: Application
    Filed: August 17, 2016
    Publication date: January 3, 2019
    Inventors: Huawei ZHOU, Guohai LIU, Jinghua JI, Wenxiang ZHAO, Qian CHEN, Long CHEN
  • Publication number: 20180323665
    Abstract: The invention proposes a new motor with separated permanent magnet torque and reluctance torque. Meanwhile, the optimal efficiency control method for this motor is proposed. This invention belongs to the field of motor and its drive system. The proposed motor includes 3 stators and 1 rotor (composed of 2 axial rotors and 1 radial rotor), the radial stator employs distributed winding, the axial stator adopts concentrated winding. The distributed winding and the radial reluctance rotor structure contribute to higher reluctance torque, while the concentrated winding and the surface mount permanent magnet structure offer higher permanent magnet torque. In the view of the magnetic circuit, the axial magnetic circuit generates the permanent magnet torque, and the radial magnetic circuit generates the reluctance torque. By using the decoupling of axial and radial magnetic circuits, the separation and the independent control of the permanent magnet torque and the reluctance torque are realized.
    Type: Application
    Filed: March 16, 2016
    Publication date: November 8, 2018
    Inventors: Qian CHEN, Wenxiang ZHAO, Guohai LIU, Jinghua JI, Gaohong XU, Zhipeng LIN