Evaluation of GaN based H-Bridge and Half- Bridge Resonant ... · 1/11/2019 Copyright © 2015 –Advanced Power Electronics & Electric Drives Lab (APEDL) 10 Goal: Testing of GaN MOSFET

Evaluation of GaN based H-Bridge and Half-

Bridge Resonant Converters in Capacitive-

Coupled Wireless Charging

Paul Han, Weiqiang Chen, Ali Bazzi, Ph.D

Advanced Power Electronics and Electric Drives Lab (APEDL)

ECE Department and Center for Clean Energy Engineering

10/16/2015

11/11/2019 Copyright © 2015 – Advanced Power Electronics & Electric Drives Lab (APEDL)

1/11/2019 2Copyright © 2015 – Advanced Power Electronics & Electric Drives Lab (APEDL)

Table of Content

• The Problem: Inductor Coupling

• The Solution: Capacitive Coupling

• Current Status: Conventional Silicon based Topologies

• Goal: Testing of GaN MOSFET based H-bridge and half bridge

• Proposed Design: GaN MOSFET Drive and PCB Schematic

• Difficulties: Designing PCB for 2Mhz operation


The Problem: Inductive Coupling

• Current wireless charging solutions

for consumer electronics utilize

inductive charging. (Qi charging,

Powermet, etc.)

- Requires bulky and expensive

copper transmit and receive

coils

Mobile phone wireless charging pad

Qi charging pad

Wireless charging pad diagram


The Solution: Capacitive Coupling

• Wireless charging based

on capacitive coupling

- Air capacitor formed by

plates on transmitter and

receiver

- Potential for slimmer

designs and simpler

manufacturing process

(e.g. metal coated plastic)

• Previously applied in

implanted medical device

charging (e.g. pacemaker)

and inter-PCB power and data transfer

• Our contribution to body of knowledge

- Performance comparison between H-

bridge and half bridge topologies in

transmitter driver


Current Status: Conventional Silicon

based Topologies

H-Bridge System:

Half-Bridge System:

DCLoad

S1

Diode Rectifier

CapacitiveInterfacing

S2

S3

S4

H-bridge

L1

L2

R1

R2

D1

D2

D3

D4

DCLoad

Half-bridge Diode Rectifier


S1

S2

C1

C2

L1

L2

R1

R2

D1

D2

D3

D4


Current Status:Testing of Silicon

MOSFET H-bridge and Half Bridge

• Computer modeling

• MATLAB Simulink

• Prototype

• Wire wrap construction

• 200kHz operation

• 60v input

• Resistive 10W load

Current Status: Matlab Simulink


• Efficiency calculated based on input/output power

• Simplified MOSFET model based on conduction losses only

Current Status: Prototype


• Prototype • Function generators

used for gate drive • 10W Resistive load• Efficiency calculated

using input/output power

• Note: Buck converter omitted

Current Status: Prototype Results


H-bridge System

Blue: H-bridge output voltage

Red: Tank voltage

H-Bridge SystemGreen: Tank Current


Goal: Testing of GaN MOSFET based

H-bridge and Half bridge

• Benefits

• Low losses• Low output and input

capacitance

• Eliminates reverse recovery loss

• Low switching losses

• High frequency operation• Goal of 2Mhz operation (old

100kHz)

• Allows for small components, lower losses, greater range

• Simulations predict efficiency of 90% for H-bridge, 95% for Half bridge

• Detriments

• Expense

• Difficulties of designing PCB for

high frequency operation

• No experience


Proposed Design: GaN MOSFET

Drive

DC/DC Converter& Supply Isolator

Voltage Regulator+9V

+7V

+5V

Digital Isolator

Gate Driver

GaNMOSFET


Proposed Design: PCB

Schematic

Voltage Regulator

+9V

+7V

+5V

Power Supply

DC/DC Converter& Supply Isolator


Proposed Design: PCB

Schematic

Gate Driver

Power Stage and Drive Circuit

Digital Isolator

+7V

PWM input Port

H-bridge

Half-bridge

Rectifier

Rectifier



Gate-driver


Difficulties: Designing PCB for 2Mhz

operation

• Current ideas

- 4 layer board (separate power and signal grounds)

- Metal shielding of h-bridge and half bridge

- Equal length traces

• Tips from articles- Keep analog, digital and power supply separate in board

- Steady signal flow from left to right

- Start locating critical components

- Bypassing the power supply into high speed circuity by using parallel

capacitors- In high frequency circuits, small parasitic can influence performance

- Consider skin effect: It causes current to flow in the outer surfaces of a

conductor – in effect making the conductor narrower, thus increasing the

resistance from its dc value

- Minimizing long parallel runs and close proximity of signal traces to reduce inductive coupling; minimizing long traces on adjacent layers to

prevent capacitive coupling

Documents

Evaluation of GaN based H-Bridge and Half- Bridge Resonant ... · 1/11/2019 Copyright © 2015 –Advanced Power Electronics & Electric Drives Lab (APEDL) 10 Goal: Testing of GaN MOSFET