Ken L Tran

US Patent:

8226900, Jul 24, 2012

Filed:

Aug 14, 2006

Appl. No.:

11/503662

Inventors:

Igor Elkin - Malden MA, US
Alan Millner - Lexington MA, US
Ken Tran - North Chelmsford MA, US
Madhuwanti Joshi - Edison NJ, US

Assignee:

MKS Instruments, Inc. - Andover MA

International Classification:

B01J 19/08

US Classification:

42218607, 204176

Abstract:

A transformer-less power supply is provided for ozone generation. The power supply advantageously reduces costs and increases reliability of ozone generators. The power supply provides a first AC voltage from a power source to a resonant circuit and the resonant circuit provides a second AC voltage to the ozone generating unit, the second AC voltage being greater than the first AC voltage. A controller for the power supply that adapts to the resonance of the circuit to provide control with a wide tolerance for the high Q circuit component values of the circuit.

US Patent:

8520413, Aug 27, 2013

Filed:

Aug 17, 2011

Appl. No.:

13/211892

Inventors:

Ken Tran - North Chelmsford MA, US
Feng Tian - Salem NH, US
Franklin Lee - Framingham MA, US
Wangbo Zhang - Winchester MA, US

Assignee:

MKS Instruments, Inc. - Andover MA

International Classification:

H02M 3/335

US Classification:

363 2103, 323222, 323271, 323287, 363 39

Abstract:

A power converter includes first and second circuit modules, a first capacitor, a second diode and a control module. The first circuit module includes a switching element in parallel with a first diode. The second circuit module includes a first inductor and the first circuit module. The inductor is in series with the first circuit module. The first capacitor is in parallel with the second circuit module. The second diode includes a first terminal and a second terminal, where the first terminal is in series with the second circuit module and the first capacitor, and the second terminal is coupled to a second power terminal. The control module varies one or more of the first capacitor and the first inductor based on at least one of a current of a load circuit or an input voltage. A resonating waveform is generated by a resonant circuit of the second circuit and is used by the control module to turn off the switching element under zero-current and zero-voltage conditions.

US Patent:

8641978, Feb 4, 2014

Filed:

Jun 20, 2012

Appl. No.:

13/528580

Inventors:

Igor Elkin - Malden MA, US
Alan Millner - Lexington MA, US
Ken Tran - North Chelmsford MA, US
Madhuwanti Joshi - Edison NJ, US

Assignee:

MKS Instruments, Inc. - Andover MA

International Classification:

B01J 19/08

US Classification:

42218607

Abstract:

A transformer-less power supply is provided for ozone generation. The power supply advantageously reduces costs and increases reliability of ozone generators. The power supply provides a first AC voltage from a power source to a resonant circuit and the resonant circuit provides a second AC voltage to the ozone generating unit, the second AC voltage being greater than the first AC voltage. A controller for the power supply that adapts to the resonance of the circuit to provide control with a wide tolerance for the high Q circuit component values of the circuit.

US Patent:

20070103092, May 10, 2007

Filed:

Nov 7, 2005

Appl. No.:

11/268692

Inventors:

Alan Millner - Lexington MA, US
Thomas Alexander - Andover MA, US
Ilya Bystryak - Salem MA, US
Ken Tran - North Chelmsford MA, US
Madhuwanti Joshi - Burlington MA, US

International Classification:

H05B 41/16

US Classification:

315276000

Abstract:

According to a first aspect, a power supply and a method of providing power for igniting a plasma in a reactive gas generator is provided that includes (i) coupling a series resonant circuit that comprises a resonant inductor and a resonant capacitor between a switching power source and a transformer, the transformer having a transformer primary and a plasma secondary; (ii) providing a substantially resonant AC voltage from the resonant capacitor across the transformer primary, thereby inducing a substantially resonant current within the transformer primary to generate the plasma secondary; and (iii) upon generation of the plasma secondary, the resonant inductor limiting current flowing to the switching power supply. According to another aspect, bipolar high voltage ignition electrodes can be used in conjunction with inductive energy coupling to aid in plasma ignition.

US Patent:

20100219757, Sep 2, 2010

Filed:

Feb 27, 2009

Appl. No.:

12/394904

Inventors:

Souheil Benzerrouk - Lowell MA, US
Siddharth P. Nagarkatti - Acton MA, US
Andrew Cowe - Andover MA, US
Ali Shajii - Canton MA, US
Jesse E. Ambrosina - Topsfield MA, US
Ken Tran - North Chelmsford MA, US
Xing Chen - Lexington MA, US

International Classification:

H05H 1/24

US Classification:

31511151

Abstract:

Described are methods and apparatuses, including computer program products, for igniting and/or sustaining a plasma in a reactive gas generator. Power is provided from an ignition power supply to a plasma ignition circuit. A pre-ignition signal of the plasma ignition circuit is measured. The power provided to the plasma ignition circuit is adjusted based on the measured pre-ignition signal and an adjustable pre-ignition control signal. The adjustable pre-ignition control signal is adjusted after a period of time has elapsed.

US Patent:

20120287545, Nov 15, 2012

Filed:

May 13, 2011

Appl. No.:

13/106920

Inventors:

Ken Tran - North Chelmsford MA, US
Feng Tian - Salem NH, US
Xing Chen - Lexington MA, US

Assignee:

MKS Instruments, Inc. - Andover MA

International Classification:

H02H 3/08

US Classification:

361101

Abstract:

A switching apparatus includes a first transistor, a second transistor, a first circuit module, a first current sensor and a control circuit. The first transistor includes first, second and third terminals. The first terminal of the first transistor is coupled to a first power terminal. The third terminal of the first transistor includes a gate or base of the first transistor. The second transistor includes first, second and third terminals. The first terminal of the second transistor is coupled to a second power terminal. The second terminal of the second transistor is coupled to the second terminal of the first transistor. The third terminal of the second transistor includes a gate or base of the second transistor. The first circuit module includes an inductor in parallel with a diode. The first circuit module is connected between the first terminal of the second transistor and the second power terminal.

US Patent:

20130257301, Oct 3, 2013

Filed:

Mar 28, 2012

Appl. No.:

13/432415

Inventors:

Ken Tran - North Chelmsford MA, US
Feng Tian - Salem NH, US
Xing Chen - Lexington MA, US
Franklin Lee - Framingham MA, US

Assignee:

MKS INSTRUMENTS, INC. - Andover MA

International Classification:

H01J 37/248

US Classification:

315200 R

Abstract:

Improvements in the supply of high-frequency electrical power to ozone-producing cells can be accomplished using the systems and techniques described herein. Application of a DC-DC converter operating at a switching frequency substantially greater than a load frequency, supports generation of a high-voltage AC for powering such cells, while allowing for reductions in component size and reductions in a quality factor of a load tuning circuit. Controllable power inverters used in obtaining one or more of the switching and load frequencies can be controlled using feedback techniques to provide stable, high-quality power to ozone-producing cells under variations in one or more of externally supplied power and load conditions. An inrush protection circuit can also be provided to selectively introduce a current-limiting resistance until an input DC bus has been sufficiently initialized as determined by measurements obtained from the DC bus. The current limiting resistance can be a positive-temperature coefficient thermistor.

US Patent:

20130257311, Oct 3, 2013

Filed:

Mar 27, 2012

Appl. No.:

13/431521

Inventors:

KEN TRAN - North Chelmsford MA, US
XING CHEN - Lexington MA, US
RUSSELL L. NEWMAN - South Hamilton MA, US
FRANKLIN LEE - Framingham MA, US

Assignee:

MKS INSTRUMENTS, INC. - Andover MA

International Classification:

H05B 41/24

US Classification:

315279, 315287

Abstract:

A power system for a dielectric barrier discharge system, such as used for generating ozone, can include a full bridge inverter stage and parallel resonant tank outputting a signal for powering a dielectric barrier discharge cell stack. The inverter stage is controlled using a combination of pulse width modulation (PWM) and frequency modulation (FM) to enable soft switching through all load conditions—from full load to light load. A current control loop error amplifier compensator can provide a duty cycle adjustment signal to a phase shift PWM controller chip that generates the switching signals for the inverter stage. A feedback signal is also used to adjust a clock frequency time constant of the PWM controller chip to provide the FM. In one embodiment, the feedback signal is an output of an inverting amplifier connected at an output of the current control loop error amplifier compensator.