Patents by Inventor Lihua Chen

Lihua Chen 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).

  • Publication number: 20180281600
    Abstract: A vehicle powertrain includes a monolithically integrated load switch, mirror switch, and temperature array, and a gate driver. The gate driver includes a first comparator configured to filter a current level of the mirror switch, and a second comparator configured to provide a reference to the first comparator based on temperature array output such that a gate discharge rate of the switch, enabled by the first comparator, varies proportionally with a temperature adjusted filtered current level.
    Type: Application
    Filed: March 29, 2017
    Publication date: October 4, 2018
    Inventors: Yan Zhou, Lihua Chen, Shuitao Yang, Fan Xu, Mohammed Khorshed Alam, Baoming Ge
  • Publication number: 20180287601
    Abstract: A gate driver of a power device includes an inductor and a supply. The inductor is configured to, during a transitional period of the power device, convert a potential on a gate to a field, and the field to an opposite potential to toggle the gate and charge a floating capacitor to the opposite potential as an excess field collapses. The supply is configured to maintain the gate at the potential and generate the excess field during a non-transitional period.
    Type: Application
    Filed: March 29, 2017
    Publication date: October 4, 2018
    Inventors: Shuitao Yang, Yan Zhou, Lihua Chen, Fan Xu
  • Patent number: 10090792
    Abstract: A powertrain includes a first and second switch coupled in parallel to drive an electric machine and a gate driver. The gate driver may be configured to, in response to a transition request while a first temperature of the first switch exceeds a second temperature of the second switch, inject a current onto a gate of the second switch to drive rates of change of current through the first and second switch to the electric machine to a same value.
    Type: Grant
    Filed: December 8, 2016
    Date of Patent: October 2, 2018
    Assignee: Ford Global Technologies, LLC
    Inventors: Fan Xu, Yan Zhou, Shuitao Yang, Mohammed Khorshed Alam, Lihua Chen
  • Publication number: 20180236877
    Abstract: A powertrain for a vehicle includes an electric machine coupled with a first inverter, a traction battery and a second inverter. The traction battery is coupled between a neutral terminal of the electric machine and a negative terminal of the first inverter. The second inverter is coupled in parallel with the first inverter with respect to a direct current (DC) bus, and configured to drive a second electric machine.
    Type: Application
    Filed: February 21, 2017
    Publication date: August 23, 2018
    Inventors: Baoming Ge, Lihua Chen, Yan Zhou, Shuitao Yang, Fan Xu
  • Publication number: 20180215269
    Abstract: A vehicle powertrain includes a variable voltage converter, a bypass diode and a controller. The bypass diode may be coupled in parallel with the converter and configured to clamp an output of the converter to a battery voltage. The controller may be configured to, while in a boost mode and in response to a rate of change of a converter inductor current exceeding a boost threshold, open switches of the converter to divert propulsive energy through the bypass diode. The controller may also be configured to, while in buck mode and in response to a magnitude of a converter inductor current exceeding a buck threshold, open switches of the converter to divert regenerative energy through the bypass diode, while reversed biased, to the battery.
    Type: Application
    Filed: January 31, 2017
    Publication date: August 2, 2018
    Inventors: Mohammed Khorshed Alam, Yan Zhou, Shuitao Yang, Fan Xu, Lihua Chen
  • Publication number: 20180219546
    Abstract: A gate driver of a power device includes a power supply and a resonant circuit. The power supply may have a positive potential and a negative potential. The resonant circuit may include an inductor and be configured to recirculate charge during turn-off by inducing a first field based on a positive charge from a gate caused by the positive potential, and in response to reversal of a voltage across the inductor, collapsing the first field to draw charge from the gate.
    Type: Application
    Filed: January 31, 2017
    Publication date: August 2, 2018
    Inventors: Shuitao Yang, Fan Xu, Yan Zhou, Lihua Chen, Mohammed Khorshed Alam
  • Patent number: 10035422
    Abstract: A DC link capacitor coupled to positive and negative DC busses between a high voltage DC source and an electric vehicle inverter is quickly discharged during a shutdown. An active discharge circuit connected across the link capacitor has a discharge resistor in series with a discharge switch. The discharge switch has a control terminal for selectably turning the discharge switch on and off. A disable circuit is coupled to the control terminal and is responsive to a disable command signal to turn off the discharge switch. The disable circuit turns on the discharge switch upon cessation of the disable command signal. A timing circuit powered by a voltage from the link capacitor initiates a predetermined time interval upon cessation of the disable command signal, and continuously turns off the discharge switch after the predetermined time interval while the voltage from the link capacitor remains above a threshold.
    Type: Grant
    Filed: June 14, 2016
    Date of Patent: July 31, 2018
    Assignee: FORD GLOBAL TECHNOLOGIES, LLC
    Inventors: Yan Zhou, Yuqing Tang, Hongjie Wu, Lihua Chen, Shahram Zarei
  • Publication number: 20180205340
    Abstract: A vehicle may include an electric machine including windings having a nonzero phase offset. The vehicle may further include first and second inverters configured to drive the electric machine as a result of toggling of switches. The switches may be toggled according to respective pulse width modulation (PWM) signals. One or more gate drivers may be configured to generate the PWM signals. The PWM signals may be based on fundamental waveforms having a phase shift that is based on the nonzero phase offset of the electric machine.
    Type: Application
    Filed: January 17, 2017
    Publication date: July 19, 2018
    Inventors: Lihua Chen, Baoming Ge, Shuitao Yang, Shahram Zarei
  • Publication number: 20180194234
    Abstract: A vehicle power system may include a gate driver configured to drive a traction gate and a generator gate corresponding to switches of a variable voltage controller such that the gates have alternating pulse width modulation ON periods. The gates may be driven in response to a throughput magnitude falling below a threshold. The gate driver may be further configured to drive the gates such that a duty cycle of one of the gates is zero in response to the throughput exceeding the threshold.
    Type: Application
    Filed: January 12, 2017
    Publication date: July 12, 2018
    Inventors: Fan Xu, Shuitao Yang, Yan Zhou, Mohammed Khorshed Alam, Lihua Chen
  • Publication number: 20180198401
    Abstract: A variable voltage converter for an electric drive system has upper and lower switching devices in series between positive and negative buses. An inductance couples a junction between the switching devices to a DC battery. A controller is configured to drive the switches according to PWM gate signals based on an expected boost ratio of the converter. The PWM gate signals have a nominal dead-time insertion for both the upper and lower switching devices when the expected boost ratio is greater than a predetermined boost ratio. In order to extend a range of achievable boost ratios during regeneration operation, the PWM gate signals are without dead-time insertion for the upper switching device and the lower switching device remains continuously off when the expected boost ratio is less than the predetermined boost ratio.
    Type: Application
    Filed: January 12, 2017
    Publication date: July 12, 2018
    Inventors: JOGENDRA S. THONGAM, SHUITAO YANG, MOHAMMED KHORSHED ALAM, LIHUA CHEN, FAN XU, YAN ZHOU
  • Publication number: 20180167013
    Abstract: A powertrain includes a first and second switch coupled in parallel to drive an electric machine and a gate driver. The gate driver may be configured to, in response to a transition request while a first temperature of the first switch exceeds a second temperature of the second switch, inject a current onto a gate of the second switch to drive rates of change of current through the first and second switch to the electric machine to a same value.
    Type: Application
    Filed: December 8, 2016
    Publication date: June 14, 2018
    Inventors: Fan XU, Yan ZHOU, Shuitao YANG, Mohammed Khorshed ALAM, Lihua CHEN
  • Publication number: 20180154784
    Abstract: A vehicle powertrain includes a switch configured to provide a drive current to an electric machine and coupled with a diode array and a gate driver. The gate driver may be configured to, in response to a voltage across the array exceeding a threshold while providing the drive current in a presence of a turn-off request, confine operation of a resistive switch to a linear region to decrease a rate of change of the drive current proportional to the voltage.
    Type: Application
    Filed: December 1, 2016
    Publication date: June 7, 2018
    Inventors: Fan Xu, Shuitao Yang, Yan Zhou, Lihua Chen, Mohammed Khorshed Alam
  • Publication number: 20180154787
    Abstract: A powertrain includes a DC-DC converter, an electric machine, and a controller. The DC-DC converter may be configured to output a bus voltage. The controller may be configured to, in response to a torque request exceeding an available torque of the electric machine, command the converter to boost the bus voltage to a discrete step value selected from a predetermined number of available discrete step values, that changes in response to a selected operating mode of the powertrain changing, to increase the available torque.
    Type: Application
    Filed: December 1, 2016
    Publication date: June 7, 2018
    Inventors: Lihua Chen, Yan Zhou, Shuitao Yang, Mohammed Khorshed Alam, Fan Xu
  • Publication number: 20180138694
    Abstract: A vehicle may include an inverter including a tristate buffer. The vehicle may further include a short detection circuit connected to the inverter configured to output an inhibit signal indicative of abnormal electrical behavior to the tristate buffer such that inverter output is disabled. The short detection circuit may out the inhibit signal in response to a high value comparator signal indicating deviation from a high voltage threshold or a low value comparator signal indicating deviation from a ground voltage.
    Type: Application
    Filed: November 15, 2016
    Publication date: May 17, 2018
    Inventors: Jaswant Singh Garcha, Lihua Chen, Shahram Zarei
  • Publication number: 20180099574
    Abstract: A vehicle includes an electric machine configured to provide propulsive force to the vehicle, and a power inverter configured to supply power from a traction battery to the electric machine using a first and second switch configured as a half-bridge, wherein the first switch is controlled by a gate driver. The gate driver is configured to operate in a soft turn-off mode when a load current exceeds a threshold for a time period defined by a mask timer, operate in a fast turn-off mode when the load current is below the threshold, and in response to a turn-off request received prior to expiration of the mask timer after the load current exceeds the threshold, enable the soft turn-off mode.
    Type: Application
    Filed: October 12, 2016
    Publication date: April 12, 2018
    Inventors: Yan Zhou, Shuitao Yang, Lihua Chen, Fan Xu, Mohammed Khorshed Alam
  • Patent number: 9931944
    Abstract: A vehicle powertrain includes a bypass diode and a controller. The bypass diode is configured to clamp an inverter DC terminal voltage to a battery voltage. The controller is configured to, while the terminal voltage is within a predetermined range of the battery voltage, maintain off a lower IGBT of a DC-DC converter while in a propulsion mode, and modulate the lower IGBT to increase the terminal voltage to maintain the bypass diode reverse biased while in a regenerative mode.
    Type: Grant
    Filed: March 22, 2016
    Date of Patent: April 3, 2018
    Assignee: Ford Global Technologies, LLC
    Inventors: Mohammed Khorshed Alam, Lihua Chen, Yan Zhou, Fan Xu
  • Publication number: 20180079315
    Abstract: A DC link capacitor in a drive system for an electric vehicle is quickly discharged using only local action within an inverter module and without any extra components to dissipate the charge. The inverter has a phase leg comprising an upper switching device and a lower switching device coupled across the capacitor. A gate driver is coupled to the phase leg to alternately switch the switching devices to ON state according to a PWM signal during pulse-width modulation of the drive system. The gate driver is configured to discharge the link capacitor during a discharge event by simultaneously activating the upper and lower switching devices to transitional states. Thus use of transitional states ensures that the switching devices provide an impedance that dissipates the capacitor charge while protecting the devices from excessive temperature.
    Type: Application
    Filed: September 19, 2016
    Publication date: March 22, 2018
    Inventors: SHUITAO YANG, YAN ZHOU, FAN XU, MOHAMMED KHORSHED ALAM, LIHUA CHEN
  • Publication number: 20180072158
    Abstract: A vehicle system in a hybrid vehicle comprises a controller configured to generate for output a modulated voltage to a direct current capacitor to prevent voltage spikes on the capacitor in response to receiving a reference current via a direct current voltage clamping control block that outputs a reference current in response to a difference between a feedback voltage and a reference voltage exceeding a threshold.
    Type: Application
    Filed: September 9, 2016
    Publication date: March 15, 2018
    Inventors: Shuitao Yang, Yan Zhou, Fan Xu, Lihua Chen
  • Publication number: 20180065489
    Abstract: A vehicle may include an electric drive system including switches having gates configured to control the switches. The vehicle may include a galvanic isolation coupling having a primary side electrically connected with an input power source and a secondary side electrically connected with a gate driver circuit. The gat driver circuit has a controller configured to actuate the gates and a power supply circuit electrically connected to the controller to provide backup power. The galvanic isolation coupling may be a flyback converter.
    Type: Application
    Filed: September 6, 2016
    Publication date: March 8, 2018
    Inventors: Yan Zhou, Shuitao Yang, Lihua Chen, Yuqing Tang, Hongjie Wu
  • Publication number: 20180022220
    Abstract: A power module provides one or more power transistors and support elements in a card shape. The pins/terminals for signal-level input/outputs (e.g., gate drive, current sensor, and temperature sensor signals) are arranged in two parallel layers. The power terminals (e.g., positive and negative bus, and output junction of a phase leg) are preferably arranged in just one of the layers. The signal pins are spaced both laterally across a long edge of the power module and transversely to the edge direction, so that the minimum spacings (i.e., clearances) can be achieved while shortening the lateral length of the edge(s) of the power module. Preferably, the signal pins belonging to an individual power transistor (e.g., an IGBT or MOSFET) are distributed between the two layers so that corresponding signal loops can be magnetically decoupled from the power terminal loop.
    Type: Application
    Filed: July 20, 2016
    Publication date: January 25, 2018
    Inventors: FAN XU, LIHUA CHEN