Short Summer Training for KMUTT student on
2009 October and November in UEC
Period: 4 weeks between 2009 October 18th andNovember 13th.
Location : UEC Department of Electronic Engg., 1-5-1,Chofu, Tokyo 182-8585 JapanUEC Surpervisory staff :Assoc. Prof. Kohji Higuchi (higuchi@ee.uec.ac.jp)
Tec. Exp. Tatsuyoshi Kajikawa(kajikawa@ee.uec.ac.jp)
TA Yoshihiro Ohta (ohta@francis.ee.uec.ac.jp)

KMUTT Leader

KMUTT Leader :Lecturer Kamon Jirasereeamornkul (Electronic Engg..
KMUTT)
Number of Training student:
One Trainee student Theeraphat Poomalee fromDept. of Electronic .Engg was accepted to stay at
UEC for High Performance Digital Control
Experiments of DC-DC Converter training.

Program agenda
Advanced digital control of a DC-DC converter is performed, and it isverified by experiments that the start-up characteristics and the loadsudden change characteristics are improvable. Therefore, the following
procedures are required and the training is advanced according tofollowing schedule.
10.18-10.25 Design and Manufacture of DC-DC Converter
10.26-10.31 Design and Manufacture of Digital Controller using DSP
11.1-11.7 Experiments of Start-up Responses
11.8-11.12 Experiments of Dynamic Load Responses
11.13
Presentation of Training Results

Training results
In this training program, student from KMUTT could manufactured DC‑DC Converter
and the con ｔ roller of DC-DC converter using DSP. He could
experienced the experiments of high performance digital control of DCDC converter. He studied the advanced digital control is very goodcompared to usual PI control from experiments.
Last day he showed the good results which he got by the presentation.
This presentation was shown also in KMUTT through theteleconference.
To the following the data of a presentation and photographs of thesituation of the presentation and training. are shown.

Ｐｒｅｓｅｎｔａｔｉｏｎ document

RobustRobust DC-DC
DC-DC buckbuck converter
converter
withwith fully
fully digital
digital controllercontroller

At The University of Electro-Communications (UEC), Japan
Presented by Theeraphat Poomalee
King Mongkut's University of Technology Thonburi

Outline
123
456

Introduction• The demands on switching converter trend to increase its
robustness capabilities.
• Conventional analog controller can be replaced by thedigital controller to perform high flexible robust controlsystem.
• Using DSP supports more complexity of control algorithm.

Digital signal processing unit

DC-DC Converter

Working principleof DC-DC converter
iLState space modelieox& = A C x + B C u⎡e ⎤x = ⎢ o⎥⎣ i ⎦ACy = eO1⎡⎢− C ROL= ⎢1⎢ −⎢⎣LOy = Cxu = ei G P = 2

1 ⎤CO ⎥⎥R− O ⎥L O ⎥⎦⎡ 0 ⎤BC = ⎢G P ⎥
⎢ L ⎥
⎣ O ⎦

C = [10]

Ro is combined resistance of the switch
Q1 and the inductor Lo.

Working principle
Simulation results of the controlled object•RL= 0.33 Ohms
•Lo = 0.5 uH•Co = 235 uH

Open-loop characteristic of controlled object

System poles Æ -2.44×104±9.15×104i
Overshoot = 44%

Closed-loop PID control
Applying simple PID controller
DC-DC
converter

kp=2.5 ki=0.5 kd=-12Controller

Closed-loop robust control
DC-DC
converter

2DOF digital controller with estimated state feedback

Controller

Closed-loop robust control
Applying 2 degree-of-freedom digital controller using state feedback
k1= (-F(1,1)-F(1,2)*FF(1,1)+((-F(1,4)-F(1,2)*FF(1,4))*(-F(1,2)/FF(1,2)))(G*H*H4+G*H*Fz)*(Kz)*((1)/(1+H2)))
k2= (-F(1,2)/FF(1,2)-G*H*(Kz)*((1)/(1+H2)))
k3= (-F(1,3)-F(1,2)*(FF(1,3)))k4= (Fz)ki= (h*(G*H*H4+G*H*Fz)*(Kz)*(1))
kiz= (h*G*H*Kz)
where
FF(1,4)=-Bd(1,1)/Ad(1,2)
FF(1,2)=Ad(1,2)
FF(1,1)=-Ad(1,1)/Ad(1,2)
FF(1,3)=-Ad(1,3)/Ad(1,2)
Fz=-F(1,4)-F(1,2)*FF(1,4)
And
Ad, Bd are expanded discrete time state space model.
F is state feed-back matrices.
GH is steady state gain.

ExperimentDC-DCconverter

H1=-0.2
H2=-0.9
H3=-0.1
H4=-0.5
Kz=0.2
Desired feedback system
poles & zeroes

2 degree-of-freedom digital controller using state feedback Input voltage = 9-11 V
Output voltage = 3.3 V
Output ripple at full load < 100 mVrms
Controller propertiesPWM frequency 200 kHz
PWM step resolution 150Controller

k1=0.3402
k2=0.0210
k3=-0.0058
k4=0.1122
ki=-0.0301
kiz=0.0727
Parameters of controller

Experiment
Open loop gain of the plant testing
Output (volts)•Switching frequency = 200 kHz•Sampling frequency = 200 kHz• PWM value 0-150 is mapped into duty
cycle 0-100• Input voltage of converter = 10 Volts
75

PWM value

Simulation results
Output (volts)

2DOF digital controller with estimated state feedback

Step response in different load

Experimental results
Hardware implementation
Buckconverter

Input
10 VdcOutput3.3 V 10A

FilterGate driver

TMS320C2000TM
PiccoloTM MCU
System clock = 60 MHZ

Experimental results
Start-up response
2 DOF digital controller

PID controller

Start-up time = 140 uS

Start-up time = 225 uS

RL= 0.33Ohms Time/DIV = 100uS

Experimental results
Start-up response
2 DOF digital controller

PID controller

RL= 0.25 Ohms

Start-up time = 140 uS

Start-up time = 225 uS

RL= 0.25 Ohms Time/DIV = 100uS

Experimental results
Start-up response
2 DOF digital controller

PID controller

Start-up time = 140 uS

Start-up time = 225 uS

RL= 0.33+220uF Ohms Time/DIV = 100uS

Experimental results
Steady state

Event indicatorshows the alterationof the duty cycle

70 mVp-p

RL= 0.33 Ohms
Output ripple = 70 mVp-p
Time/DIV = 100uS

Experimental results
Dynamic load response
2 DOF digital controller

PID controller
15A

15A
10A

10A

120 mV
140 mV

Output voltage variation = 120mV
Time/DIV = 200uS

Output voltage variation = 140mV
Time/DIV = 200uS

Experimental results

DOF digital
digital controller
controller
22 DOF

Simple PID
PID controller
controller
SimpleProvides fast start-up and good
dynamic-load response.
No overshoot and ringing
appeared in start-up phase withinvarious load.

Some ringing and overshoot may
be arisen in start-up period.
Slower response to the dynamicload.
Fast controller and higher loop
gain may produce some oscillation.

Conclusions

 The robust control algorithm can be achieved via the useof digital controller .
 The implemented system can overcome the variation ofdynamic load as well as good start-up response.
 Only output voltage feedback is used.
 The proposed algorithm requires high performance DSP
and high resolution of PWM generator.

Reference[1] E. Takegami, K. Higuchi, K. Nakano, S. Tomioka, and K.Watanabe“The Method for Determining Parameters of Approximate 2DOF Digital
Controller for Robust Control of DC-DC Converter” ECTI transactions onelectrical eng., electronics, and communications vol.4, no.1 february,2006.

Training
Activities

Some prepared PCBs of DC-DC converter

Training

Assembled hardware of DC-DC converter

TrainingGet training how to program the microcontrollerTraining

Some control algorithm explanation

Training

Working site

Training

Teeraphat and TA Ohta

Training

Show training to KMUTT, Small screen is KMUTT

Training

Show training to KMUTT using teleconference
Ohta, Kamon, Higuchi, Teeraphat

Training

Participated in lab meetingPresentation

Theeraphat Poomalee

PresentationHiguchi lab members

Presentation

Theeraphat Poomalee

Presentation

Discussion together with KMUTTPresentation

Show presentation to KMUTT
Vice President of KMUTT and Prof. Kosin

Presentation

KMUTT students ask questions

Presentation

Prof. Miki ask questions