60 V-to-35 kV Input-Parallel Output-Series DC-DC DD...

Circuit Design Implementation

60 V-to-35 kV Input-Parallel Output-Series DC-DCConverter Using Multi-Level Class-DE Rectifiers

Sanghyeon Park*, Lei Gu*, and Juan Rivas-Davila* Sanghyeon Park and Lei Gu made an equal contribution to this work.

Stanford University Power Electronics Research (SUPER) Lab

Project GoalTo develop a small-sized lightweight

dc-dc converter for high-voltage low-

current applications (10-100s kV and

1-100 mA) such as electrostatic

precipitation, milk pasteurization or

X-ray / neutron beam generation.

Class-DE Rectifier

300V

+

(a)

Cb

Cb D

D

(d)

k

20-Stage

Rectifiers

k

20-Stage

Rectifiers

k

20-Stage

Rectifiers

6 kV

+

6 kV

+

6 kV

+

36 kV

+

Full-Bridge Inverters

QQ

QQ

QQ

Cs

Cs

Cs

Cs

Cs

Cs

Lp

Ls

Lp

Ls

Lp

Ls

VDD = 60 V

Experimental Results60V-to-6kV dc-dc converter,single unit

60V-to-35kV dc-dc converter,6 units stacked

60V-to-6kV dc-dc converter, single unit

60V-to-35kV dc-dc converter, 6 units stacked

• Switching frequency = 1.25 MHz

• Input voltage = 60 V

• Output voltage = 6 kV

• Output current = 6 mA

• DC-to-DC efficiency = 81 %

• Rise time = 200 μs

• Output voltage waveform

- horizontal: 500 us/div

- vertical: 6 kV/div (3:1 attenuated in the fig.)

• Switching frequency = 1.25 MHz

• Input voltage = 60 V

• Output voltage = 35 kV

• Output current = 5.83 mA

• DC-to-DC efficiency = 73 %

• Rise time = 296 μs

• Power density = 5.1 W/in3

• Specific power = 1.1 W/g

• Thermal image after 3 minutes of

continuous operation (6 kV, 6 mA output)

• Dimension (L×W×H) = 8 in × 2.5 in × 2 in

(20 cm × 6 cm × 5 cm)

20-Stage

Class-DE

Rectifiers,

6 kVdc output

Planar air-core

PCB transformer1.25 MHz

full-bridge

inverter,

60 Vdc input

Kapton films

for dc isolation

Batteries for scale

Batteries for scale

1st level converter

2nd level converter

6th level converter

Motivation

Transformer: 155 ◦C

Ambient: 23 ◦C

IEEE APEC 2018, San Antonio, TX, March 8, 2018

• Many emerging applications can benefit

from a compact high-voltage power supply.

- miniaturized electrostatic precipitator(Talukder, Park, & Rivas, 2017)

• Existing technologies are often too bulky

and heavy for small scale applications.

Six inverters

connected in

parallelSix rectifiers

connected in

series

Transformers

providing dc

isolation

• Weight = 188 g

• Lateral view

ESP off ESP on

- portable milk pasteurizer(Raymond, Liang, Gu, & Rivas, 2015)

300V+

Vout = 6 kV

+

20-Stage Class-DE Rectifiers

CBb,20

CBb,21

CBt,20

300V+

CBt,n+1

300V+

CBb,n

CBt,n

CBb,n+1

CBb,1

CBt,1

300V+