Keming Q Chen

US Patent:

6856521, Feb 15, 2005

Filed:

Aug 19, 2003

Appl. No.:

10/643732

Inventors:

Keming A. Chen - Torrance CA, US
James F. Lazar - Moorpark CA, US
Lateef A. Kajouke - San Pedro CA, US

Assignee:

General Motors Corporation - Detroit MI

International Classification:

H02M003/335
H02M007/44
H02M003/24

US Classification:

363 17, 363 98, 363132

Abstract:

A DC/DC converter includes a first leg and a second leg. A controller employs hard switching in the first leg to reduce the conduction loss. The controller employs zero voltage in the second leg to reduce the switching loss.

US Patent:

7106605, Sep 12, 2006

Filed:

Jun 30, 2004

Appl. No.:

10/881213

Inventors:

Keming Chen - Torrance CA, US
Lateef A. Kajouke - San Pedro CA, US
James F. Lazar - Moorpark CA, US

Assignee:

General Motors Corporation - Detroit MI

International Classification:

H02H 7/125

US Classification:

363 52, 363126

Abstract:

A DC-DC converter comprises an input circuit that stores inductive energy that includes a first switch that releases the stored inductive energy. A transformer includes a primary winding that communicates with the input circuit and a secondary winding. An output circuit communicates with the secondary winding and that includes first and second output conductors and a first diode that communicates with one end of the secondary winding and the first output conductor. A second diode communicates with one end of the secondary winding and the second output conductor. A third diode communicates with an opposite end of the secondary winding and the first output conductor. A fourth diode communicates with an opposite end of the secondary winding and the second output conductor. A first capacitor is connected in parallel to the third diode. A second capacitor is connected in parallel to the fourth diode.

US Patent:

7116012, Oct 3, 2006

Filed:

Jul 30, 2003

Appl. No.:

10/630496

Inventors:

Lateef A. Kajouke - San Pedro CA, US
Keming A. Chen - Torrance CA, US
James F. Lazar - Moorpark CA, US

Assignee:

General Motors Corporation - Detroit MI

International Classification:

H02J 7/00

US Classification:

307 64, 323222, 363 15, 363 60, 363127

Abstract:

A power conversion circuit includes a current section, a transformer, and a voltage section. The current section includes inductors configured to produce a boosted output voltage from a voltage sourse when then current section is operating in a forward direction. The transformer includes a primary winding electrically coupled to the secondary winding and configured to drive a load. The voltage section includes a pluralaty of balancing switchtes configured to actively driven to provide a DC voltage to the load. The balancing switches balance energy between the current section and the voltage section when the power conversion circuit is the load and operating in the forward direction.

US Patent:

7312653, Dec 25, 2007

Filed:

Mar 10, 2005

Appl. No.:

11/077475

Inventors:

Keming Chen - Torrance CA, US
David Tang - Fontana CA, US

Assignee:

GM Global Technology Operations, Inc. - Detroit MI

International Classification:

G01F 1/10

US Classification:

327545, 361245, 361246

Abstract:

A reverse polarity protected system comprises a voltage source that includes positive and negative terminals. A polarity-sensitive device has a first terminal that communicates with the positive terminal of the voltage source, and that includes a second terminal. A low-resistance switch communicates with the first and second terminals of the voltage source, and communicates with the second terminal of the polarity-sensitive device. The low-resistance switch assumes a conducting state between the second terminal of the polarity-sensitive device and the negative terminal of the voltage source when a first voltage at the positive terminal of the voltage source minus a second voltage at the negative terminal of the voltage source is greater than a threshold voltage. Otherwise, the low-resistance switch assumes a non-conducting state.

US Patent:

7345861, Mar 18, 2008

Filed:

Aug 23, 2005

Appl. No.:

11/209559

Inventors:

Keming Chen - Torrance CA, US

Assignee:

GM Global Technology Operations, Inc. - Detroit MI

International Classification:

H02H 9/00

US Classification:

361 56, 361 58, 361 91, 361 931, 361118, 361119, 3613211

Abstract:

A capacitor circuit with surge protection that is selectively connected between a voltage source and a device includes a first capacitance element has one end that communicates with a first terminal of the voltage source. A first transistor has a first terminal that communicates with an opposite end of the first capacitance element and a second terminal that communicates with a second terminal of the voltage source. A control terminal of the first transistor communicates with a capacitor enable signal that provides a controlled turn-on to limit current surge and turns off the first transistor when voltage surge is detected.

US Patent:

7393236, Jul 1, 2008

Filed:

Sep 2, 2005

Appl. No.:

11/219228

Inventors:

Alex Thompson - Fullerton CA, US
Mark D. Korich - Chino Hills CA, US
Mark L Selogie - Hermosa Beach CA, US
Keming Chen - Torrance CA, US

Assignee:

GM Global Technology Operations, Inc. - Detroit MI

International Classification:

H01R 13/00

US Classification:

439487, 361711

Abstract:

An electrical system as described herein is suitable for use in an electric or hybrid vehicle. The electrical system includes electrical devices, such as power transistors, coupled to an electrically and thermally conductive bus bar. The respective nodes of the electrical devices are coupled to the bus bar such that the bus bar carries a combined signal generated by the electrical devices. The bus bar is also thermally coupled to a conduction heat transfer system, such as a liquid cooled cold plate. Thus, the bus bar functions as both an electrical conduit and a conduction-based heat sink for the electrical system.

US Patent:

7492316, Feb 17, 2009

Filed:

Jul 6, 2006

Appl. No.:

11/480982

Inventors:

Aitan Ameti - Germantown MD, US
Keming Chen - Herndon VA, US
Robert J. Fontana - Potomac MD, US
Edward A. Richley - Gaithersburg MD, US
Belinda Turner - Germantown MD, US

Assignee:

Multispectral Solutions, Inc. - Germantown MD

International Classification:

G01S 3/02

US Classification:

342465, 342463

Abstract:

Instead of normalizing time reference of independent spatially-located clocks using a reference tag transmission from known location, the present invention uses an interarrival time interval between a pulse pair of UWB pulses as a timing metric. Thus, a method of synchronizing spatially-located clock or normalizing time indications thereof comprises transmitting a UWB pulse pair, determining at first and second monitoring stations a respective count value indicative of a locally measured time interval between received pulse pairs, determining a ratio between clock counts of first and second monitoring stations, and utilizing the ratio to determine clock skew, e. g. , a timing correction to be applied to respective local clocks of the monitoring stations. A corresponding system comprises a reference tag transmitter that transmits a pulse pair of UWB pulses to define a time reference interval, a first independent receiver that receives the pulse pair to generate a first count value indicative an interarrival interval between the pulse pair, a second independent receiver that receives the pulse pair to similarly generate a second count value, and a processor hub responsive to the count values to determine a ratio corresponding to the ratio of respective clock frequencies of the first and second receiver clocks. Once the correction is applied, time-of-arrival information from object tag transmissions may be used to determine object location with sub-foot position accuracies.

US Patent:

7586760, Sep 8, 2009

Filed:

Dec 18, 2007

Appl. No.:

11/959003

Inventors:

Keming Chen - Torrance CA, US

Assignee:

GM Global Technology Operations, Inc. - Detroit MI

International Classification:

H02M 3/335
H02H 7/122

US Classification:

363 17, 363 5605, 363 25

Abstract:

A DC-to-DC converter and associated methods are provided for controlling the discharge of snubber capacitances during a light/no load buck mode of operation. An operating method for a DC-to-DC converter detects conditions corresponding to a light/no load buck mode of operation, and, in response to the detection of that mode, controls the states of a first switch, a second switch, a first switched diode element, a second switched diode element, a third switched diode element, and a fourth switched diode element to facilitate discharging of a first capacitance element and a second capacitance element through a secondary winding of a transformer.