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An Overview of Research Activities in
CONTROL THEORY & ENGINEERING
Qing-Chang Zhong, Fellow of IET, [email protected]
Senior Research Fellow, Royal Academy of Engineering
Professor in Control Engineering
Dept. of Aeronautical and Automotive Engineering
Loughborough University
United Kingdom
A little bit about myself1990, started working in the area of control
1997, MSc in Control Theory & Eng. from Hunan University
2000, PhD in Control Theory & Eng. from Shanghai Jiaotong University
2004, PhD in Control & Power from Imperial College London, awarded the Best Thesis
Prize
2006, first research monograph Robust Control of Time-delay Systems published by
Springer-Verlag London.
2007, Director of EPSRC-funded Network for New Academics in Control Engineering,
currently more than 130 members, to join UKACC from Oct 2010 as a Group Member
with support from UKACC.
2009, Senior Research Fellow of Royal Academy of Engineering /Leverhulme Trust
2010, Fellow of IET
2010, Professor in Control Engineering, Loughborough University
2010, research monograph Control of Integral Processes with Dead Time to be published
by Springer-Verlag.
2011, research monograph Control of Power Inverters for Distributed Generation and
Renewable Energy to be published by Wiley-IEEE Press.
Q.-C. ZHONG: AN OVERVIEW OF ACTIVITIES IN CONTROL THEORY & ENGINEERING – p. 2/20
Brief overview of research activities
1998 2004 2001
Process Control
Robust Control Theory & Time-Delay Systems
Control in Power Electronics & Renewable Energy
Year2007
Control in Automotive & Aeronautical Eng.
2010
Res
earc
h ac
tivi
ties
2013
Cover control theory and applications in:
Chemical engineering
Electrical engineering
Aeronautical engineering
Automotive engineering
Number of papers in the top
two journals in control:
IEEE Transactions on
Automatic Control: 7Automatica: 4
Q.-C. ZHONG: AN OVERVIEW OF ACTIVITIES IN CONTROL THEORY & ENGINEERING – p. 3/20
Activities in control theoryMainly three threads:
Robust control of time-delay systems: A series of fundamental problems in this area have
been solved:
Projections
J-spectral factorisation
Delay-type Nehari problem
Standard H∞ problem of single-delay systems
Unified Smith predictor
Realisation of distributed delays in controllers
Infinite-dimensional systems: applied the generic theory of infinite-dimensional systems
to time-delay systems and solved problems about feedback stabilizability, approximate
controllability, passivity etc
Uncertainty and disturbance estimator (UDE)-based robust control: can be applied to
linear or nonlinear, time-varying or time-invariant systems with or without delays;
attracted several Indian groups to work on this.
Q.-C. ZHONG: AN OVERVIEW OF ACTIVITIES IN CONTROL THEORY & ENGINEERING – p. 4/20
Activities in chemical engineeringControl of integral processes with dead-time: A research monograph, Control of Integral
Processes with Dead Time, jointly with Antonio Visioli from Italy, is to appear in 2010.
Disturbance observer-based control strategy
Dead-beat response
Stability region on the control parameter space
Achievable specifications etc
Practical experience with a production line
16 reactors, controlled by 3 industrial computers
Effective object code > 100 KB (Intel 8086 assembler)
Analogue control variables and measurements etc.
Continuous Stirred Tank Reactor (CSTR) System
Antonio Visioli and Qing-Chang Zhong
Control of Integral Processes
with Dead Time
Springer
Berlin Heidelberg NewYork
HongKong London
Milan Paris Tokyo
Q.-C. ZHONG: AN OVERVIEW OF ACTIVITIES IN CONTROL THEORY & ENGINEERING – p. 5/20
Activities in electrical engineeringPower electronics: A research monograph, Control of Power Inverters for Distributed
Generation and Renewable Energy, is to be published by Wiley-IEEE Press in early 2011.
Provision of a neutral line
Power quality improvement: H∞ repetitive control
Grid-friendly inverters: Synchronverters
Parallel operation of inverters
Multi-sourced UPS
Inverter-dominated power systems
Electrical drives:
DC drives
AC drives
Fault-tolerant control of bearingless motors
Renewable energy
wind powerQ.-C. ZHONG: AN OVERVIEW OF ACTIVITIES IN CONTROL THEORY & ENGINEERING – p. 6/20
Neutral line provision
Vave
0.2V/div
iN
50A/div
iL
50A/div
ic
20A/div
0.17 0.18 0.19 0.20 0.21 0.22 0.23 0.24 0.25 0.26 0.27
Time (sec)
Proposed a topology and control algorithms to provide a stable balanced
neutral line for inverters.
This decouples its control from that of the inverter;
It enables independent phase control for inverters;
Can be used for multi-level inverters as well.
Q.-C. ZHONG: AN OVERVIEW OF ACTIVITIES IN CONTROL THEORY & ENGINEERING – p. 7/20
Power quality improvementPower quality is a very important problem for renewable energy and
distributed generation.
Phase-lead
low-pass
filter
DC power
source
Inverter
bridge
LC
filter
Transformer
PWM
modulation
Internal model M
and stabilizing
compensator C
Id*
Iq*
irefe
abc
dq
θ
Current controller
PLL
ugbuga ugc
u
+
+
+
+
+
+
u’gb
u’ga
u’gc
u’
u’gb
u’ga
u’gc
ia ib ic
-
+
-+
-
+
-3
-2
-1
0
1
2
3C
urr
ent
[A]
0.00 0.01 0.02 0.03 0.04 0.05
Time [sec]
#1:1
#1:2
The recorded current THD
was 0.99%, while the grid
voltage THD was 2.21%.
Q.-C. ZHONG: AN OVERVIEW OF ACTIVITIES IN CONTROL THEORY & ENGINEERING – p. 8/20
Parallel operation of inverters
Ro1 Ro2
1 1E δ∠ 2 2E δ∠1 1 1S P jQ= +0V∠
Z
2 2 2S P jQ= +
0.1 0.15 0.2 0.25 0.3−200
−100
0
100
200
Vo (
V)
0.1 0.15 0.2 0.25 0.3−40
−20
0
20
40
Time (Seconds)
i 1, i2 (
A) i
1i2
(a) Output currents and the
common voltage vo
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.40
400800
120016002000
P1, P
2 (W
)0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4
−2000
200400600800
Time (Seconds)Q
1, Q2 (
Var
)
P1
P2
Q1
Q2
(b) Active power and reactive
power of both invertersQ.-C. ZHONG: AN OVERVIEW OF ACTIVITIES IN CONTROL THEORY & ENGINEERING – p. 9/20
Inverter-dominated Power SystemsGenerator 1
Renewable
Energy Source
Energy
Storage
Inverter
Circuit
Breaker
Generator 2 Generator n
Renewable
Energy Source
Energy
Storage
Inverter
Circuit
Breaker
Renewable
Energy Source
Energy
Storage
Inverter
Circuit
Breaker
AC BUS
Public Grid
Q.-C. ZHONG: AN OVERVIEW OF ACTIVITIES IN CONTROL THEORY & ENGINEERING – p. 10/20
Activities in aeronautical engineeringCurrently working on two Sandpit projects in this area:
Energy recovery from landing aircraft
Integrating and automating airport operations
Coils
Risen slope to fall when energy recovery is activated
Aircraft
Runway Magnets with alternative poles (N, S, N, …)
0 0.1 0.2 0.3 0.4 0.5-6000
-4000
-2000
0
2000
4000
6000
Pha
se A
vol
tage
0 0.1 0.2 0.3 0.4 0.5-1
-0.5
0
0.5
1x 10
5
Time
Pha
se A
cur
rent
Q.-C. ZHONG: AN OVERVIEW OF ACTIVITIES IN CONTROL THEORY & ENGINEERING – p. 11/20
Activities in automotive engineeringHardware-in-the-loop (HIL) simulation and rapidcontrol prototyping (RCP)
dSPACE systems
MicroGen systems
Developing a powerful HIL system
(Hybrid) electrical vehicles
HEV driver model
AC Ward Leonard drive systems
Plug-in charging systems
Energy flow/storage/management systems
Initial work done on engine control (combinedheat and power, CHP)
Q.-C. ZHONG: AN OVERVIEW OF ACTIVITIES IN CONTROL THEORY & ENGINEERING – p. 12/20
HEV driver modelJoint work with Dr Shen et al at Ricardo UK.
Regenerative braking is an important feature of HEVs. According to the EU regulations, if the
travel of brake pedal is used to derive the regenerative braking torque then more stringent brake
safety requirements need to be met. The use of the engine or vehicle speed inevitably introduces
a discontinuous powertrain torque when the acceleration pedal is released or when the brake pedal
is applied, which causes oscillations in the torque. A rule-based driver model with look-ahead
information is proposed and tested in an HIL system consisting of an HCU and a vehicle model.
0 200 400 600 800 1000 12000
50
100
150
Veh
icle
Spe
ed(k
m/h
)
0 200 400 600 800 1000 1200−0.5
0
0.5
1
Ped
al p
ositi
onga
s>0,
bra
ke<
0
0 200 400 600 800 1000 1200−100
0
100
200
Tor
que
(Nm
)B
lue−
engi
ne, R
ed−
ISG
0 200 400 600 800 1000 12000
2000
4000
Eng
ine
Spe
ed
(rpm
)
0 200 400 600 800 1000 12000.6
0.62
0.64
0.66
Sta
te o
f Cha
rge
Time (sec)
ECE ECE ECE ECE
EUDC
Restart engine
ISG torque ro restart engine
Engine idle stopShift to 2nd
to 3rd
to 4th
to 5th
Driver
HC
U
Pedals
VehicleVehicle
Reference Speeds
Vehicle Speeds
Clu
tch
Clu
tch
Tra
nsm
issi
on
Tra
nsm
issi
on
Fin
al D
rive
Fin
al D
riveISGISG
ICEICE
BatteryBattery
MCU
EMS
TCU
BMS
Control flow Information flow Power flowVehicle SystemsModel in dSPACE
HCU strategyIn control Unit
Performancemonitor
Q.-C. ZHONG: AN OVERVIEW OF ACTIVITIES IN CONTROL THEORY & ENGINEERING – p. 13/20
AC Ward Leonard drive systemsExtended the concept of Ward Leonard drive systems to AC machines. Extremely good for PMSM
used in (hybrid) electrical vehicles.
Constant speed
Variable speed
Controllable field Fixed field
Prime mover
Load Variable speed
Variable speed
Fixed field
SM/IM Load
SG Prime mover VDC
Inverter
(a) Conventional (DC) Ward Leonard drive systems (b) AC Ward Leonard drive systems
(c) Experimental results when reversing the motor: speed (left) and current (right)Q.-C. ZHONG: AN OVERVIEW OF ACTIVITIES IN CONTROL THEORY & ENGINEERING – p. 14/20
EV charging systems
Synchronverters are inverters that are operated according
to the mathematical model of synchronous generators and
thus are grid-friendly. Can be used for STATCOMs, the
grid connnection of renewable energy as well.
While charging the batteries, they also provide frequency
and voltage support to the grid.
Can automatically change the energy flow between the AC
bus and the DC bus.
Time (Second)
P(W
)an
dQ
(Var
)
P���
Q
��
Q.-C. ZHONG: AN OVERVIEW OF ACTIVITIES IN CONTROL THEORY & ENGINEERING – p. 15/20
High-speed trains
Compensation of negative-sequence currents.
A
C
B
ab
c
A
B
C
ic
ubc
iLa
irb
RPC
Three- phase V/ V
traction transformer
Single-phase
step-down
transformer
220KV
27. 5 KV27. 5 KV
iLb
Single-phase
step-down
transformer
C
iB iC iA
ib ia
irauac
Converter aConverter b
LaLb
Q.-C. ZHONG: AN OVERVIEW OF ACTIVITIES IN CONTROL THEORY & ENGINEERING – p. 16/20
Collaborative networksNationally, leading the EPSRC-funded New-ACE network
Partners: Imperial, Sheffield, Loughborough and Queen’s Belfast.With more than 130 members from academia and industryHas already started making an impact
Internationally
Closely working/worked with researchers from Italy, Israel, China,
Brazil, France, Netherlands, Singapore and USA8 visits to/from Israeli collaborators last yearJointly writing a book with Antonio Visioli from ItalyDelivered about 20 presentations at universities and conferences in
the UK, US, Israel, Poland and China in 2009Several Indian groups are very interested in our researchEstablished strong links with State Grid, institutions and
universities in ChinaHave jointly received a ¥1M grant from the Ministry of Science
and Technology, China (+ ¥1M matching fund)Have established an EU consortium to prepare a FP7 proposal
Q.-C. ZHONG: AN OVERVIEW OF ACTIVITIES IN CONTROL THEORY & ENGINEERING – p. 17/20
Funding: Just over £1MCurrent ongoing projects:
EPSRC KTA: £120,447, one postdoc
EPSRC, TSB and Power Systems Warehouse: £181,527, one postdoc
Ministry of Science and Tech., China: ¥1M (+ ¥1M matching fund)
Royal Academy of Engineering: £41k, a replacement lecturer
EPSRC: EP/H004351/1, £112k, a postdoc
EPSRC: EP/H004424/1, £68k, a PhD studentEPSRC: EP/E055877/1, £88k, a part-time secretary
EPSRC and Add2: DHPA Award, £90k, a PhD studentEPSRC and Nheolis: DHPA Award, £90k, a PhD studentEPSRC: one DTA studentship, a PhD student
Completed projects:
EPSRC: EP/C005953/1, £126k, a postdoc
Q.-C. ZHONG: AN OVERVIEW OF ACTIVITIES IN CONTROL THEORY & ENGINEERING – p. 18/20
Research team
One part-time secretary
Currently 5 PhD students, 1 postdoctoral researchfellow and 2 Honorary Researchers
Another 4 postdoctoral researchers and 2 PhDstudents to join soon
A former postdoctoral research fellow is still inactive collaboration
Q.-C. ZHONG: AN OVERVIEW OF ACTIVITIES IN CONTROL THEORY & ENGINEERING – p. 19/20
Knowledge exchange activitiesPatent applications filed
Q.-C. Zhong, AC Ward Leonard Drive Systems, UK Patent filed,
Application No.: GB0916886.5, September 2009.
Q.-C. Zhong, Energy Recovery System for Landing Aircraft, UK
Patent filed, Application No.: GB0823432.0, December 2008.
Q.-C. Zhong and G. Weiss, Inverters that Mimic Synchronous
Generators, UK Patent filed, Application No.: GB0820699.7, Nov.
2008.
Another two applications are being prepared.
KTP: Power Systems Warehouse Ltd
KTA: EPSRC to increase the TRL of the synchronverter
technology
EPSRC DHPA: add2 UK and Nheolis FranceQ.-C. ZHONG: AN OVERVIEW OF ACTIVITIES IN CONTROL THEORY & ENGINEERING – p. 20/20
