Rixin Lai

US Patent:

20120134188, May 31, 2012

Filed:

Nov 30, 2010

Appl. No.:

12/956835

Inventors:

Rixin Lai - Clifton Park NY, US
Joseph Smolenski - Slingerlands NY, US

Assignee:

GENERAL ELECTRIC COMPANY - Schenectady NY

International Classification:

H02M 1/00
H02M 7/42
H02P 27/06
G05F 5/00

US Classification:

363 95, 323299

Abstract:

An electric machine drive system is described. The system includes an inverter, an electric machine coupled to the inverter by at least one output conductor and including a ground connection, and an active common mode current reducing device coupled between the ground connection of the electric machine and the inverter.

US Patent:

20120249145, Oct 4, 2012

Filed:

Mar 31, 2011

Appl. No.:

13/076823

Inventors:

Rixin Lai - Clifton Park NY, US
Luis Jose Garces - Niskayuna NY, US
Juan Antonio Sabate - Gansevoort NY, US
Juan Manuel Rivas Davila - Niskayuna NY, US
Song Chi - Clifton Park NY, US
Wesley Michael Skeffington - Clifton Park NY, US

Assignee:

GENERAL ELECTRIC COMPANY - SCHENECTADY NY

International Classification:

G01R 33/44
H03F 3/68

US Classification:

324318, 330124 R

Abstract:

A gradient amplifier system is presented. An embodiment of a gradient amplifier system that includes a power stage having a plurality of bridge amplifiers, where each of the plurality of bridge amplifiers operates at a first switching frequency. The gradient amplifier system further includes a gradient coil coupled to an output terminal of the power stage and configured to produce a magnetic field proportional to a coil current signal supplied by the power stage. In addition, the gradient amplifier system includes a controller stage coupled to an input terminal of the power stage and configured to generate a pulse width modulated gate signal based on the coil current signal and a reference current signal, where the pulse width modulated gate signal is generated at a second switching frequency upon occurrence of a slew rate associated with the reference current signal is below a determined threshold rate and an amplitude level associated with the reference current signal is above a determined level. Further, the controller stage is configured to apply the generated pulse width modulated gate signal to the power stage for changing an operating frequency of each of the plurality of bridge amplifiers from the first switching frequency to the second switching frequency.

US Patent:

20130162250, Jun 27, 2013

Filed:

Dec 10, 2012

Appl. No.:

13/709812

Inventors:

General Electric Company - Schenectady NY, US
Wesley Michael Skeffington - Clifton Park NY, US
Song Chi - Clifton Park NY, US
Rixin Lai - Clifton Park NY, US
Yimeng Shi - Hangzhou, CN
Yanjun Zhang - Shanghai, CN

Assignee:

General Electric Company - Schenectady NY

International Classification:

G01R 33/36
G01R 33/54

US Classification:

324309, 324322

Abstract:

A gradient amplifier system, includes: a power stage comprising a plurality of bridge amplifiers, each operates at a first switching frequency; a gradient coil coupled to the power stage and configured to produce a magnetic field proportional to a coil current signal supplied by the power stage; a controller stage coupled to an input terminal of the power stage and configured to: generate a pulse width modulated gate signal based on the coil current signal and a reference current signal, wherein the pulse width modulated gate signal is generated at a second switching frequency when a slew rate associated with the reference current signal is below a threshold rate for at least a first time period; and apply the pulse width modulated gate signal to the power stage for changing an operating frequency of each of the plurality of bridge amplifiers from the first to the second switching frequency.

US Patent:

20130162370, Jun 27, 2013

Filed:

Dec 22, 2011

Appl. No.:

13/335582

Inventors:

Rixin Lai - Clifton Park NY, US
Joseph Smolenski - Slingerlands NY, US

International Classification:

H03H 7/01

US Classification:

333177, 29605, 333181

Abstract:

Systems and methods for an electric choke are provided. The choke may be provided as part of a power transmission arrangement that includes a cable for electrically coupling a power source and a powered device having a ground node and a wire separate from the cable providing a path for a common-mode current through the ground node. The power transmission arrangement also includes an unbalanced choke coupled between the power source and the powered device, wherein a number of turns of the cable in the choke is different than a number of turns of the wire in the choke.

US Patent:

20140077812, Mar 20, 2014

Filed:

Sep 14, 2012

Appl. No.:

13/618909

Inventors:

Juan Antonio Sabate - Niskayuna NY, US
Rixin Lai - Clifton Park NY, US
Lei Wang - Niskayuna NY, US

Assignee:

GENERAL ELECTRIC COMPANY - Schenectady NY

International Classification:

G01R 33/34
G01R 33/341

US Classification:

324319, 324322

Abstract:

In one embodiment, a system includes a gradient coil driver configured to supply electrical signals to a gradient coil of a magnetic resonance imaging system. The gradient coil driver includes an electronic circuit. The electronic circuit includes a first H-bridge circuit electrically coupled to a power source. The first H-bridge includes a plurality of metal-oxide-semiconductor field-effect transistor (MOSFET) switches; and a plurality of diodes electrically coupled in parallel with each MOSFET switch. Each diode of the plurality of diodes is configured to conduct current to cause zero voltage potential across a source and a drain of one of the plurality of MOSFET switches. The first H-bridge also includes a load configured to regulate currents flowing through each of the plurality of diodes and each MOSFET switch of the plurality of MOSFET switches.

US Patent:

20160154046, Jun 2, 2016

Filed:

Dec 1, 2014

Appl. No.:

14/556744

Inventors:

- Schenectady NY, US
Yan Pan - Niskayuna NY, US
Rixin Lai - San Jose CA, US

International Classification:

G01R 31/02
G01R 31/08

Abstract:

A ground fault detection system for locating a ground fault in a direct current (DC) power transfer system is provided. The system includes a ground fault detection component and a current sensor. The ground fault detection component includes a first switch and a first resistive element electrically coupled to each other in a series configuration. The ground fault detection component also includes a second switch and a second resistive element electrically coupled to each other in a series configuration. Furthermore, the current sensor is operatively coupled to a load and is configured to measure a fault current at the load upon switching at least one of the first switch or the second switch to a conducting state.

US Patent:

20160126726, May 5, 2016

Filed:

Nov 5, 2014

Appl. No.:

14/533762

Inventors:

- SCHENECTADY NY, US
Dong Dong - Schenectady NY, US
Rixin Lai - San Jose CA, US

International Classification:

H02H 9/04

Abstract:

An over-voltage protection system includes an electronic valve connected across two terminals of a circuit and an over-voltage detection circuit connected across one of the plurality of semiconductor devices for detecting an over-voltage across the circuit. The electronic valve includes a plurality of semiconductor devices connected in series. The over-voltage detection circuit includes a voltage divider circuit connected to a break-over diode in a way to provide a representative low voltage to the break-over diode and an optocoupler configured to receive a current from the break-over diode when the representative low voltage exceeds a threshold voltage of the break-over diode indicating an over-voltage condition. The representative low voltage provided to the break-over diode represents a voltage across the one semiconductor device. A plurality of self-powered gate drive circuits are connected to the plurality of semiconductor devices, wherein the plurality of self-powered gate drive circuits receive over-voltage triggering pulses from the optocoupler during the over-voltage condition and switch on the plurality of semiconductor devices to bypass the circuit.

US Patent:

20160072375, Mar 10, 2016

Filed:

Sep 10, 2014

Appl. No.:

14/482969

Inventors:

- Schenectady NY, US
Luis Jose Garces - Niskayuna NY, US
Ravisekhar Nadimpalli Raju - Clifton Park NY, US
Rixin Lai - Clifton Park NY, US
Di Zhang - Niskayuna NY, US

International Classification:

H02M 1/00
H02M 3/335

Abstract:

A system and method for series connecting electronic power devices are disclosed. In one embodiment, a switching device system includes a first upper arm electrically coupled to a first lower arm and a second upper arm electrically coupled to a second lower arm. Each of the arms include a plurality of low voltage sub-modules connected in series and each plurality of low voltage sub-modules includes an auxiliary switching device, a series switching device, and a capacitor. Each plurality of low voltage sub-modules is configured to be sequentially switched using the auxiliary switching device and the series switching device separately in the upper arms and the respective lower arms to control change in voltage over time (dV/dt) while selectively blocking a desired high voltage. Further, a capacitor voltage balancing (sorting or rotating) algorithm may be used to actively balance voltage across each plurality of low voltage sub-modules.