Patents by Inventor Wenxi Yao
Wenxi Yao 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).
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Publication number: 20220376633Abstract: A resonance control method for differentiated phase correction under asymmetric positive and negative bilateral frequency domains includes a differentiated phase correction resonance control link with an independent phase correction angle at each resonance point, a decoupling link and a delay compensation link. As a high power converter has the characteristic of asymmetric positive and negative bilateral frequency domains under resonance control with decoupling, stability margin of a control link is enhanced while a negative-sequence current suppression capability is realized by means of differentiated phase correction at positive and negative resonance poles.Type: ApplicationFiled: January 18, 2021Publication date: November 24, 2022Inventors: Wuhua LI, Ye YAN, Yuxiang WANG, Chushan LI, Wenxi YAO, Xiangning HE, Youtong FANG
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Patent number: 10377598Abstract: A control system for controlling operation of main and secondary drive units in a web winder system to provide tension control of a continuous material web is disclosed. The control system causes the main drive unit to operate in a velocity mode to set a linear velocity of the continuous material web. The control system receives inputs from tension and speed detectors in the web winder system that detect a tension and speed of the continuous material web and causes the secondary drive unit to operate in a modified torque regulated closed-loop tension control mode so as to control a tension in the web material, with the control system causing the secondary drive unit to operate according to a torque regulated closed-loop tension control mode and integrate a speed feedback loop into the torque regulated closed-loop tension control mode so as to introduce active damping into the tension control.Type: GrantFiled: February 17, 2017Date of Patent: August 13, 2019Assignees: Eaton Intelligent Power Limited, Zhejiang UniversityInventors: Huaqiang Li, Wenxi Yao, Fayi Chen, Zhengyu Lu
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Patent number: 10340776Abstract: The present invention provides an acceleration method for V/f controlled induction motor in flux-weakening region, which comprises: acquiring no-load magnetizing current Im of the induction motor at current stator frequency; selecting a smaller one of 0.5·Im(1/?+1) and (Im2+?)/(Im+?Im) as magnetizing current set point, in which ? is an estimated total leakage inductance coefficient; getting an error signal by subtracting the magnetizing current of the induction motor from the magnetizing current set point; determining the stator frequency for the next control period according to the error signal which is provided as a controlling variable of negative feedback. The acceleration method of the present invention can provide the maximum output torque in flux-weakening region and has a larger tolerance for the error of the estimated leakage inductance.Type: GrantFiled: August 25, 2015Date of Patent: July 2, 2019Assignees: Eaton Intelligent Power Limited, Zhejiang UniversityInventors: Kevin Lee, Kai Wang, Wenxi Yao
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Patent number: 10333444Abstract: A control system for actively damping an output of an adjustable speed drive (ASD) having a DC link thin film capacitor is programmed to calculate a d-axis damping coefficient and a q-axis damping coefficient for stabilizing an output of the ASD based at least on a voltage across the DC link thin film capacitor at a steady operating point. The control system is further programmed to extract d-axis and q-axis perturbations in d-axis and q-axis output currents of the ASD using a high pass filter, damp the d-axis perturbation and the q-axis perturbation with the d-axis damping coefficient and the q-axis damping coefficient, respectively, and calculate a damping frequency based on the damped d-axis perturbation and the damped q-axis perturbation. The control system is also programmed to damp an angle of rotation of a reference motor speed command for controlling the ASD using the damping frequency.Type: GrantFiled: August 31, 2017Date of Patent: June 25, 2019Assignees: Eaton Intelligent Power Limited, Zhejiang UniversityInventors: Huaqiang Li, Wenxi Yao, Zhentian Qian
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Publication number: 20190068097Abstract: A control system for actively damping an output of an adjustable speed drive (ASD) having a DC link thin film capacitor is programmed to calculate a d-axis damping coefficient and a q-axis damping coefficient for stabilizing an output of the ASD based at least on a voltage across the DC link thin film capacitor at a steady operating point. The control system is further programmed to extract d-axis and q-axis perturbations in d-axis and q-axis output currents of the ASD using a high pass filter, damp the d-axis perturbation and the q-axis perturbation with the d-axis damping coefficient and the q-axis damping coefficient, respectively, and calculate a damping frequency based on the damped d-axis perturbation and the damped q-axis perturbation. The control system is also programmed to damp an angle of rotation of a reference motor speed command for controlling the ASD using the damping frequency.Type: ApplicationFiled: August 31, 2017Publication date: February 28, 2019Inventors: Huaqiang Li, Wenxi Yao, Zhentian Qian
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Publication number: 20180237249Abstract: A control system for controlling operation of main and secondary drive units in a web winder system to provide tension control of a continuous material web is disclosed. The control system causes the main drive unit to operate in a velocity mode to set a linear velocity of the continuous material web. The control system receives inputs from tension and speed detectors in the web winder system that detect a tension and speed of the continuous material web and causes the secondary drive unit to operate in a modified torque regulated closed-loop tension control mode so as to control a tension in the web material, with the control system causing the secondary drive unit to operate according to a torque regulated closed-loop tension control mode and integrate a speed feedback loop into the torque regulated closed-loop tension control mode so as to introduce active damping into the tension control.Type: ApplicationFiled: February 17, 2017Publication date: August 23, 2018Inventors: Huaqiang Li, Wenxi Yao, Fayi Chen, Zhengyu Lu
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Publication number: 20170257041Abstract: The present invention provides an acceleration method for V/f controlled induction motor in flux-weakening region, which comprises: acquiring no-load magnetizing current Im of the induction motor at current stator frequency; selecting a smaller one of 0.5·Im(1/?+1) and (Im2+?)/(Im+?Im) as magnetizing current set point, in which ? is an estimated total leakage inductance coefficient; getting an error signal by subtracting the magnetizing current of the induction motor from the magnetizing current set point; determining the stator frequency for the next control period according to the error signal which is provided as a controlling variable of negative feedback. The acceleration method of the present invention can provide the maximum output torque in flux-weakening region and has a larger tolerance for the error of the estimated leakage inductance.Type: ApplicationFiled: August 25, 2015Publication date: September 7, 2017Inventors: Kevin Lee, Kai Wang, Wenxi Yao
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Publication number: 20170170753Abstract: A power converter for operating a three-phase AC electrical machine from a single phase AC power source includes an ASD having a rectifier and inverter, and an add-on power conversion module external to the ASD that is electrically connected to each of the power source and the ASD. The power conversion module includes one or more input inductors configured to store and filter single-phase AC power received from the power source and a pair of switching devices connected to each of the input inductors at an output end thereof. A controller operably connected to the power conversion module selectively controls switching of the pair of switching devices associated with each of the one or more input inductors so as to cause a sinusoidal single phase AC power to be output from the add-on power conversion module for rectification by the rectifier.Type: ApplicationFiled: December 15, 2015Publication date: June 15, 2017Inventors: Huaqiang Li, Wenxi Yao, Zhengyu Lu
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Patent number: 9667177Abstract: A power converter for operating a three-phase AC electrical machine from a single phase AC power source includes an ASD having a rectifier and inverter, and an add-on power conversion module external to the ASD that is electrically connected to each of the power source and the ASD. The power conversion module includes one or more input inductors configured to store and filter single-phase AC power received from the power source and a pair of switching devices connected to each of the input inductors at an output end thereof. A controller operably connected to the power conversion module selectively controls switching of the pair of switching devices associated with each of the one or more input inductors so as to cause a sinusoidal single phase AC power to be output from the add-on power conversion module for rectification by the rectifier.Type: GrantFiled: December 15, 2015Date of Patent: May 30, 2017Assignees: Eaton Corporation, Zhejiang UniversityInventors: Huaqiang Li, Wenxi Yao, Zhengyu Lu
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Patent number: 9525377Abstract: A system and method for determining a rotor time constant of an AC induction machine is disclosed. During operation of the induction motor, a flux signal is injected into a rotor flux command so as to generate a time-variant rotor flux. A voltage-current flux observer determines amplitudes of rotor flux variations resulting from the time-variant rotor flux, with the amplitudes of the rotor flux variations comprising an amplitude of a rotor flux variation based on a current model of the voltage-current flux observer and an amplitude of a rotor flux variation based on a combined voltage-current model of the voltage-current flux observer. A rotor time constant of the induction motor is then estimated based on the determined amplitudes of the rotor flux variations.Type: GrantFiled: May 4, 2015Date of Patent: December 20, 2016Assignee: Eaton CorporationInventors: Kai Wang, Wenxi Yao, Huaqiang Li, Zhengyu Lu
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Publication number: 20150236631Abstract: A system and method for determining a rotor time constant of an AC induction machine is disclosed. During operation of the induction motor, a flux signal is injected into a rotor flux command so as to generate a time-variant rotor flux. A voltage-current flux observer determines amplitudes of rotor flux variations resulting from the time-variant rotor flux, with the amplitudes of the rotor flux variations comprising an amplitude of a rotor flux variation based on a current model of the voltage-current flux observer and an amplitude of a rotor flux variation based on a combined voltage-current model of the voltage-current flux observer. A rotor time constant of the induction motor is then estimated based on the determined amplitudes of the rotor flux variations.Type: ApplicationFiled: May 4, 2015Publication date: August 20, 2015Inventors: Kai Wang, Wenxi Yao, Huaqiang Li, Zhengyu Lu
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Patent number: 9024569Abstract: A system and method for determining a rotor time constant of an AC induction machine is disclosed. During operation of the induction motor, a flux signal is injected into a rotor flux command so as to generate a time-variant rotor flux. A voltage-current flux observer determines amplitudes of rotor flux variations resulting from the time-variant rotor flux, with the amplitudes of the rotor flux variations comprising an amplitude of a rotor flux variation based on a current model of the voltage-current flux observer and an amplitude of a rotor flux variation based on a combined voltage-current model of the voltage-current flux observer. A rotor time constant of the induction motor is then estimated based on the determined amplitudes of the rotor flux variations.Type: GrantFiled: June 28, 2013Date of Patent: May 5, 2015Assignee: Eaton CorporationInventors: Kai Wang, Wenxi Yao, Huaqiang Li, Zhengyu Lu
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Patent number: 8988035Abstract: A system for identifying magnetizing inductance and rotor resistance of an induction machine comprises an induction machine comprising a rotor and a stator, a DC voltage bus, and a DC-to-AC voltage inverter coupled to the DC voltage bus and to the induction machine. The system also comprises a controller configured to cause the DC-to-AC voltage inverter to apply a square-wave excitation to a plurality of phases of the induction machine, determine a stator resistance of the stator of the induction machine based on the square-wave excitation, and determine a rotor resistance of the rotor of the induction machine based on the square-wave excitation. The controller is also configured to calculate a magnetizing curve for the induction machine based on the stator and rotor resistances and control the induction machine to operate based on the magnetizing curve.Type: GrantFiled: December 19, 2012Date of Patent: March 24, 2015Assignee: Eaton CorporationInventors: Kai Wang, Wenxi Yao, Huaqiang Li, Zhengyu Lu
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Publication number: 20150002071Abstract: A system and method for determining a rotor time constant of an AC induction machine is disclosed. During operation of the induction motor, a flux signal is injected into a rotor flux command so as to generate a time-variant rotor flux. A voltage-current flux observer determines amplitudes of rotor flux variations resulting from the time-variant rotor flux, with the amplitudes of the rotor flux variations comprising an amplitude of a rotor flux variation based on a current model of the voltage-current flux observer and an amplitude of a rotor flux variation based on a combined voltage-current model of the voltage-current flux observer. A rotor time constant of the induction motor is then estimated based on the determined amplitudes of the rotor flux variations.Type: ApplicationFiled: June 28, 2013Publication date: January 1, 2015Inventors: Kai Wang, Wenxi Yao, Huaqiang Li, Zhengyu Lu
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Patent number: 8861238Abstract: An alternating current-to-direct current (AC-DC) converter is provided. The converter may include a transformer having a primary side and a secondary side. A first bi-directional switch and a first inductor may be connected in series between a positive terminal of an AC source and a first terminal of the primary side of the transformer. A second bi-directional switch and a second inductor may be connected between the positive terminal of the AC source and a second terminal of the primary side of the transformer and connected in parallel with the first bi-directional switch.Type: GrantFiled: August 27, 2012Date of Patent: October 14, 2014Assignee: North Carolina State UniversityInventors: Qin Huang, Yu Du, Wenxi Yao
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Publication number: 20140167674Abstract: A system for identifying magnetizing inductance and rotor resistance of an induction machine comprises an induction machine comprising a rotor and a stator, a DC voltage bus, and a DC-to-AC voltage inverter coupled to the DC voltage bus and to the induction machine. The system also comprises a controller configured to cause the DC-to-AC voltage inverter to apply a square-wave excitation to a plurality of phases of the induction machine, determine a stator resistance of the stator of the induction machine based on the square-wave excitation, and determine a rotor resistance of the rotor of the induction machine based on the square-wave excitation. The controller is also configured to calculate a magnetizing curve for the induction machine based on the stator and rotor resistances and control the induction machine to operate based on the magnetizing curve.Type: ApplicationFiled: December 19, 2012Publication date: June 19, 2014Applicant: EATON CORPORATIONInventors: Kai Wang, Wenxi Yao, Huaqiang Li, Zhengyu Lu
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Publication number: 20130051102Abstract: An alternating current-to-direct current (AC-DC) converter is provided. The converter may include a transformer having a primary side and a secondary side. A first bi-directional switch and a first inductor may be connected in series between a positive terminal of an AC source and a first terminal of the primary side of the transformer. A second bi-directional switch and a second inductor may be connected between the positive terminal of the AC source and a second terminal of the primary side of the transformer and connected in parallel with the first bi-directional switch.Type: ApplicationFiled: August 27, 2012Publication date: February 28, 2013Applicant: NORTH CAROLINA STATE UNIVERSITYInventors: Qin Huang, Yu Du, Wenxi Yao