cedt_part9
TRANSCRIPT
INVESTIGATIONS ON BOUNDARY SELECTION FOR SWITCHING
FREQUENCY VARIATION CONTROL OF CURRENT ERROR SPACE PHASOR BASED
HYSTERESIS CONTROLLERS FOR INVERTER FED IM DRIVES
Rijil Ramchand
Research Supervisor: Prof. K. Gopakumar
PART I
An Improved Space Phasor Based Current Hysteresis Controller with
Reduced Switching Frequency Variations Using Variable Parabolic
Bands
ORGANIZATION
I. IntroductionII. Current Error Space Phasor in VC
– SVPWMIII. Parabolic Boundary for Current
Error Space PhasorIV. Vector Change Detection in
Proposed ControllerV. Sector Change Detection in
Proposed ControllerVI. Simulation Results &
Experimental ResultsVII. Conclusion
3CEDT, Indian Institute of Science,Bangalore
Introduction
PWM Voltage Source Inverter (VSI)
Voltage controlled PWM VSI Current controlled PWM VSI
Current Controlled PWM VSIAdvantages:
Simple, so can be implemented easily Excellent dynamic response
Disadvantages: Large current ripple in steady-state Generation of sub harmonic component
in the current Variation in switching frequency
4CEDT, Indian Institute of Science,Bangalore
IntroductionCurrent Controlled PWM VSI
Can be classified into:
Hysteresis Current Controller based VSI
Ramp Comparison Controller based VSI
Predictive Current Controller based VSI
Other controllers On-off controller Neural network controller Fuzzy logic controller
5CEDT, Indian Institute of Science,Bangalore
Introduction
Hysteresis Current Controller based VSI
Fixed Tolerance band Hysteresis Current Controller based VSI
Variable Tolerance band Hysteresis Current Controller based VSI
6CEDT, Indian Institute of Science,Bangalore
IntroductionFixed Tolerance band Hysteresis
Current Controller based VSI Eliminates first two disadvantages of the
conventional CC – PWM VSI It’s drawback is the variation of switching
frequency in a fundamental cycle and with variation in the motor speed. Increased switching losses in the inverter Non-optimum current ripple Excess harmonic content in the load current
causing overheating of the machine
7CEDT, Indian Institute of Science,Bangalore
Introduction
Variable Tolerance band Hysteresis Current Controller
based VSIUses variable hysteresis band to keep the switching frequency constant.
Examples are: Adaptive hysteresis band Sinusoidal hysteresis bandDisadvantages: Complex to implement Stability problems Limitations in transient performance
8CEDT, Indian Institute of Science,Bangalore
Proposed Variable Band Hysteresis Current Controller based VSI
Continuously varying Parabolic Boundary for Current Error Space Phasor
A new sector selection logic eliminating the two outer parabolas used in earlier work is proposed in the present work. This method uses the change in direction of
the current error during sector change along any one of the orthogonal axes.
9CEDT, Indian Institute of Science,Bangalore
Current Error Space Phasor in VC – SVPWM
(a) Power schematic of a three-phase (b) Voltage space phasorstructure two-level VSI fed IM drive of the two-level VSI
10CEDT, Indian Institute of Science,Bangalore
Basic switching vectors and Sectors
Basic switching vectors and sectors.
6 active vectors (V1,V2, V3, V4, V5, V6)
Axes of a hexagonal
DC link voltage is supplied to the load
Each sector (1 to 6): 60 degrees
2 zero vectors (V0, V7)
At origin
No voltage is supplied to the load
Current Error Space Phasor in VC – SVPWM
11CEDT, Indian Institute of Science,Bangalore
Current Error Space Phasor in VC – SVPWM
0
0
0
sin(60,
sin 60
sin
sin 60
( )
mS
dc
m2 S
dc
0 S 1 2
1V θ)
TV
V θT T and
V
T T T T
T
*i i i
Δi j 2 3 j 4 3A B Ci i e i e
12CEDT, Indian Institute of Science,Bangalore
Current Error Space Phasor in VC – SVPWM
sd
R L ,dt k b
iV i V *where i Δi i
**
k bΔi i
V Δi i Vs sd d
R L R Ldt dt
**
k bΔi i
Δi V i Vs sd d
R L R Ldt dt
*
*k b
Δi iV i Vs
d dL R L
dt dt
sd
R Ldt
**
m bi
where V i V
k kV V
σ
dΔi ΔVdt= dt
dt L
Integrating both the sides
k
k
VV
σ
ΔVΔi = t
L
dL ,
dt k mΔi
V V
13CEDT, Indian Institute of Science,Bangalore
Current Error Space Phasor in VC – SVPWM
1 2 0here can beeither T or T or T depending uponσ
t ,L
t
kk
(V )(V )
k
ΔV Δi
V
1
2
0
T
T and
T
σ
σ
σ
= ,L
= ,L
=L
11
22
00
(V )(V )
(V )(V )
(V )(V )
ΔVΔi
ΔVΔi
ΔVΔi
14CEDT, Indian Institute of Science,Bangalore
Current Error Space Phasor in VC – SVPWM
(c) at end of the Sector-1 ( varies from 54 to 60 approximately)
(a) at start of the Sector-1 ( varies from 0 to 7 approximately)
(b) at middle of the Sector-1 ( varies from 27 to 33 approximately),
Movement of current error space phasor (on - plane) in a few sampling intervals of VC-SVPWM based two-level VSI fed IM drive when the reference voltage space phasor
15CEDT, Indian Institute of Science,Bangalore
Current Error Space Phasor in VC – SVPWM
Current error boundary is approximated as the combination of four parabolas at 20Hz operation
16CEDT, Indian Institute of Science,Bangalore
Current Error Space Phasor in VC – SVPWM
Approximate theoretical boundary of current error space phasor for VC-SVPWM based two-level VSI fed IM drive for position of reference voltage space phasor in Sector-1 for different
operating speeds: (a) 10Hz operation, (b) 20 Hz operation, (c) 30 Hz operation, and (d) 40 Hz operation
(a) (b)
(c) (d)
17CEDT, Indian Institute of Science,Bangalore
Parabolic Boundary for Current Error Space Phasor
Four unique Parabolas acts as boundary for current error in sector-I.
This parabolic boundary varies with the frequency.
These parabolas are characterised by the equations
For other sectors the boundary defined by these parabolas will remain the same, but their orientation will change.(i.e., the X axis and Y axis will change)
2x-h =4p y-k
2y-k =4p x-h
18CEDT, Indian Institute of Science,Bangalore
Variation of parabola parameters p1, p2, h1, k2 for variation in frequency from 0 to 45 Hz
19CEDT, Indian Institute of Science,Bangalore
Parabolic Boundary for Current Error Space Phasor
Vector Change Detection in Proposed Controller
The amplitude of Δi is monitored along A, B, C, jA, jB and jC axes for vector selection
The X axis and Y axis for parabolas for different sectors are shown in table given below
20CEDT, Indian Institute of Science,Bangalore
VECTOR SELECTION FOR SECTOR- I (BASED ON INNER PARABOLIC BANDS) FOR FORWARD DIRECTION OF ROTATION OF MACHINE
21CEDT, Indian Institute of Science,Bangalore
Vector Change Detection in Proposed Controller
Sector Change Detection in Proposed Controller
Sector change detection using outer parabolic
boundary
Simulation Results for Sector change detection using outer parabolic boundary (current error along jA axis & sector are the two traces)
22CEDT, Indian Institute of Science,Bangalore
Current error during sector-1 to sector-2 change
Simulation Results showing the variation of current error along jA axis during sector change for constant frequency VC SVPWM based two level inverter (sector-3 to sector-4 change)
23CEDT, Indian Institute of Science,Bangalore
Sector Change Detection in Proposed Controller
The property of the current error space phasor that it will change it’s direction along one of the orthogonal axes jA, jB or jC during a sector change is utilized.
24CEDT, Indian Institute of Science,Bangalore
Sector Change Detection in Proposed Controller
Sector Change Detection in Proposed Controller
Proposed sector change detection logic for forward rotation of machine
Present sector
Presentvector “ON”
Axis along which there will be change in direction of
current error during sector change
Forward Rotation
jA jB jC
1 V2 or V7 or V8 * * 2
2 V3 or V7 or V8 * 3 *
3 V4 or V7 or V8 4 * *
4 V5 or V7 or V8 * * 5
5 V6 or V7 or V8 * 6 *
6 V1 or V7 or V8 1 * *
(‘*’ means continue with the same sector)
25CEDT, Indian Institute of Science,Bangalore
Block diagram of the experimental setup
26CEDT, Indian Institute of Science,Bangalore
Simulation Results
10Hz operation for VC-SVPWM & Hysteresis Controller with outer parabola
27CEDT, Indian Institute of Science,Bangalore
Simulation Results &Experimental Results
Experimental results at 10Hz operation for Proposed Hysteresis Controller with outer parabola
Simulation results at 10Hz operation for Proposed Hysteresis Controller with outer parabola
28CEDT, Indian Institute of Science,Bangalore
Simulation Results
10Hz operation for VC-SVPWM & Hysteresis Controller with outer parabola
29CEDT, Indian Institute of Science,Bangalore
Simulation Results &Experimental Results
Simulation & Experimental results at 10Hz operation for Proposed Hysteresis Controller without outer parabola
30CEDT, Indian Institute of Science,Bangalore
Experimental Results
Sector and current error along jA axis for the proposed HC
Sector and current error along jA axis for the HC with outer parabola
10Hz Operation
Output of the sector change detection block with current error along jA axis
31CEDT, Indian Institute of Science,Bangalore
20Hz operation for VC-SVPWM & Hysteresis Controller with outer parabola
32CEDT, Indian Institute of Science,Bangalore
Simulation Results
Simulation Results &Experimental Results
Experimental results at 20Hz operation for Proposed Hysteresis Controller without outer parabola
Simulation results at 20Hz operation for Proposed Hysteresis Controller without outer parabola
33CEDT, Indian Institute of Science,Bangalore
20Hz operation for VC-SVPWM & Hysteresis Controller with outer parabola
34CEDT, Indian Institute of Science,Bangalore
Simulation Results
Simulation Results &Experimental Results
Experimental results at 10Hz operation for Proposed Hysteresis Controller without outer parabola
Simulation results at 10Hz operation for Proposed Hysteresis Controller without outer parabola
35CEDT, Indian Institute of Science,Bangalore
Experimental Results
Sector and current error along jA axis for the proposed HC
Sector and current error along jA axis for the HC with outer parabola
20Hz Operation
Output of the sector change detection block with current error along jA axis
36CEDT, Indian Institute of Science,Bangalore
40Hz operation for VC-SVPWM & Hysteresis Controller with outer parabola
37CEDT, Indian Institute of Science,Bangalore
Simulation Results
Simulation Results &Experimental Results
Experimental results at 40Hz operation for Proposed Hysteresis Controller without outer parabola
Simulation results at 40Hz operation for Proposed Hysteresis Controller without outer parabola
38CEDT, Indian Institute of Science,Bangalore
Simulation Results &Experimental Results
Experimental results for Proposed Hysteresis Controller in over-modulation and six-step mode
Simulation results for Proposed Hysteresis Controller in over-modulation and six-step mode
39CEDT, Indian Institute of Science,Bangalore
Simulation Results &Experimental Results
Experimental results for Proposed Hysteresis Controller in six-step mode
Simulation results for Proposed Hysteresis Controller in six-step mode
40CEDT, Indian Institute of Science,Bangalore
Simulation Results
Acceleration of the IM from stand still to 10Hz in 2 sec
Acceleration of the IM from 30Hz to 50Hz (six step) in 2.5 sec.
41CEDT, Indian Institute of Science,Bangalore
Simulation Results
Speed reversal of the IM from 10Hz to -10Hz in 4 sec.
Acceleration of the IM from stand still to 25Hz in 3.2 sec. and sudden loading of 5Nm at 4 sec.
42CEDT, Indian Institute of Science,Bangalore
Simulation Results
Sudden step change in Isq at 4 sec. (a) Motor current (iA) and Reference current (iA*) (b) Motor Phase voltage (VAN), Motor current (iA) and Reference current (iA*)
(a) (b)
43CEDT, Indian Institute of Science,Bangalore
Experimental Results
Acceleration of the IM from stand still to 20Hz in 4sec
Acceleration of the IM from 10Hz to 20Hz in 2sec
44CEDT, Indian Institute of Science,Bangalore
Experimental Results
Machine phase voltage (vAN), and machine phase current (iA) during Transition from 30 Hz to 45 Hz operation
Machine phase voltage (vAN), and machine phase current (iA) during Transition from 45 Hz to 50 Hz operation
45CEDT, Indian Institute of Science,Bangalore
Experimental Results
Speed reversal of the IM from 20Hz to -20Hz in 6 sec.
Sudden step change in Isq -Motor Phase voltage (VAN), Motor current (iA) and Reference current (iA*)
46CEDT, Indian Institute of Science,Bangalore
Conclusion
Switching frequency pattern similar to that of VC-SVPWM is obtained.
Proposed new sector change detection logic is self-adaptive and takes the drive to six-step mode.
It keeps all the inherent advantages of space phasor based hysteresis current controllers adjacent voltage vector switching etc.
47CEDT, Indian Institute of Science,Bangalore
PART II
Hysteresis Controller based two-level VSI fed IM Drives with Simple Online Current Error Space Phasor Boundary
Estimation
ORGANIZATION
I. IntroductionII. Online Boundary Computation
for Current Error Space PhasorIII. Sector Change Detection in
Proposed ControllerIV. Vector Change Detection in
Proposed ControllerV. Simulation Results &
Experimental ResultsVI. Salient Features of Proposed
Scheme
49CEDT, Indian Institute of Science,Bangalore
Introduction
Constant switching frequency hysteresis controller fed IM drive
Computation of Boundary for current error space phasor to obtain phase voltage harmonic spectrum exactly similar to that of VC SVPWM inverter
Current error space phasor boundary is computed from estimated fundamental stator voltages along alpha and beta axes.
This will give an exact estimate of current error space phasor boundary of VC SVPWM inverter making harmonic spectrum of phase voltage same in both cases.
50CEDT, Indian Institute of Science,Bangalore
Online Boundary Computation for Current Error Space Phasor
Estimation of stator voltages along and β axes
Space phasor based equivalent circuit of Induction Motor
Vs
is
sddt rdΨ
dt
Rs σLs Rr
m rjω Ψ
ir
im
(1-σ) Ls
The equivalent circuit shown above will be used for estimating stator voltage along and β axes
51CEDT, Indian Institute of Science,Bangalore
Online Boundary Computation for Current Error Space Phasor
Estimation of stator voltages along and β axes
ss s s
dV i r
dt
��������������
����������������������������
s rs swhere L i a ������������������������������������������
rs ss rs ss s s s
di didV i r L a i r L aV
dt dt dt
���������������������������� ����������������������������������������������������������������������
From the above equivalent circuit the equation for stator voltage vector can be written as
The stator voltage vector equation can be rewritten as
52CEDT, Indian Institute of Science,Bangalore
Online Boundary Computation for Current Error Space Phasor
Estimation of stator voltages along and β axes
The stator voltage equation can be re written as when the induction motor is supplied from an inverter.
Where , is the instantaneous space phasor output from inverter
sk rs s s
diV i r L aV
dt
��������������������������������������������������������
kV��������������
** s s
k rs s s sd(i i )
V (i i )r L aVdt
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
** s s
k rs ss s s sdi d i
V (i r L ) ( i r L ) aVdt dt
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
53CEDT, Indian Institute of Science,Bangalore
Online Boundary Computation for Current Error Space Phasor
Estimation of stator voltages along and β axes
The expression for the fundamental rotor voltage vector in terms of applied inverter voltage vector, reference current vector, and current error space phasor
The fundamental stator voltage vector is given by
** s s
r k s ss s s s1 di d i
V V (i r L ) ( i r L )a dt dt
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
** s
s r s s sdi
V aV (i r L )dt
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
The fundamental stator voltage vector can be rewritten as s
s k s s sd i
V V ( i r L )dt
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
54CEDT, Indian Institute of Science,Bangalore
Online Boundary Computation for Current Error Space Phasor
Estimation of stator voltages along and β axes
The fundamental stator voltage vector along and β axes can be rewritten as
During zero vector, fundamental stator voltage vector along and β axes can be rewritten as
ss s s s
d iV i r L
dt
ss s s s
d iV i r L
dt
ss k s s s
d iV V ( i r L )
dt
ss k s s s
d iV V ( i r L )
dt
55CEDT, Indian Institute of Science,Bangalore
Online Boundary Computation for Current Error Space Phasor
From estimated Vs and Vsβ , compute instantaneous phase voltages va, vb & vc
Using the computed values of va, vb & vc, individual vector timings T1, T2 & T0 are calculated. T1 is switching time for vector , T2 is switching time for vector , and T0 is switching time for zero vectors in space vector PWM.
The instantaneous voltage error vectors , and are computed
The instantaneous current error vectors , and are computed
Compute the current error boundary along orthogonal axes jA, jB & jC
1VAAAAAAAAAAAAAA
2VAAAAAAAAAAAAAA
0VAAAAAAAAAAAAAA
1iAAAAAAAAAAAAAA
2iAAAAAAAAAAAAAA
0iAAAAAAAAAAAAAA
56CEDT, Indian Institute of Science,Bangalore
Online Boundary Computation for Current Error Space Phasor
Instantaneous stator phase voltages
The instantaneous stator phase voltages can be calculated as
as
bs
c
1 0v
V2 1 3v * *
V3 2 2v
1 32 2
57CEDT, Indian Institute of Science,Bangalore
Online Boundary Computation for Current Error Space Phasor
Switching times computation
The instantaneous stator phase voltages can be calculated as
aas s
dc
vT * T
V
bbs s
dc
vT * T
V
ccs s
dc
vT * T
V
active max minT T T
0 s activeT T T
1 max mi dT T T
2 mid minT T T
58CEDT, Indian Institute of Science,Bangalore
Online Boundary Computation for Current Error Space Phasor
Switching times computation
The table below gives how T1, T2 and T0 for different sectors can be computed from Tas, Tbs & Tcs
Sector Tmax Tmid Tmin T1 T2
1 Tas Tbs Tcs Tas - Tbs Tbs - Tcs
2 Tbs Tas Tcs Tas - Tcs Tbs - Tas
3 Tbs Tcs Tas Tbs - Tcs Tcs - Tas
4 Tcs Tbs Tas Tbs - Tas Tcs - Tbs
5 Tcs Tas Tbs Tcs - Tas Tas - Tbs
6 Tas Tcs Tbs Tcs - Tbs Tas - Tcs
59CEDT, Indian Institute of Science,Bangalore
Online Boundary Computation for Current Error Space Phasor
Instantaneous voltage errors
The instantaneous voltage errors are computed using equation given below
AAAAAAAAAAAAAA
2 21 dc s 1 sV V V 2V V cos
AAAAAAAAAAAAAA
2 2 0 02 dc s 2 sΔV = V +V - 2V V cos(60 - )
ssΔV =VAAAAAAAAAAAAAA
Vs
V1
ΔV1
α0
V1 = Vdc
Vs
V2
ΔV2
60 -α0
V2=Vdc
60CEDT, Indian Institute of Science,Bangalore
Online Boundary Computation for Current Error Space Phasor
Instantaneous current errors
The instantaneous current error magnitudes are computed using equation given below
11 1
σ
VΔi = T
L
22 2
σ
VΔi = T
L
00 0
σ
VΔi = T
L
The instantaneous current error magnitudes are then converted into components along jA, jB & jC axes for voltage vector change detection
61CEDT, Indian Institute of Science,Bangalore
Vector Change Detection in Proposed Controller
Sector VectorsOrthogonal axes for vector change
detection
1
1 jC
2 jA
7jB
8
Present
Sector
Present
Vector
Previous
Vector
Next Vector
1
17 - - 2
2 - - 7
28 1 - -
1 8 - -
7 - - 1 -
8 - - 2 -
2 jA*A A
iji ( ji ) 0
2
0 jB*B B
iji ( ji ) 0
2
1jC*
C C
iji ( ji ) 0
2
2 jA*
A A
iji ( ji ) 0
2
62CEDT, Indian Institute of Science,Bangalore
Sector Change Detection in Proposed Controller
Sector Identification using estimated Vs and Vsβ
The magnitude of fundamental stator voltage vector can be calculated as
cos α and sin α can be computed as
2 2s s sV V V
AAAAAAAAAAAAAA
s
s
Vcos
V AAAAAAAAAAAAAA
s
s
Vsin
V AAAAAAAAAAAAAA
α - axis
β - axis
α0
Vs
Vsα
Vsβ
63CEDT, Indian Institute of Science,Bangalore
Sector Change Detection in Proposed Controller
Sector Identification using estimated Vs and Vsβ
Present
Sector
Next
Sector
Present vector Cos α Sin α
12
V2 or V7 or V8 < 0.5 > 0.866
23
V3 or V7 or V8 < -0.5 < 0.866
34
V4 or V7 or V8 = -1 <= 0
45
V5 or V7 or V8 > -0.5 < -0.866
56
V6 or V7 or V8 > 0.5 > -0.866
61
V1 or V7 or V8 = 1 >= 0
Present
Sector
Next
SectorPresent
vectorCos α Sin α
1 6 V6 or V7 or V8 = 1 <= 0
2 1 V1 or V7 or V8 > 0.5 < 0.866
3 2 V2 or V7 or V8 > -0.5 > 0.866
4 3 V3 or V7 or V8 = -1 >= 0
54
V4 or V7 or V8 < -0.5> -
0.866
65
V5 or V7 or V8 < 0.5< -
0.866
Conditions to be satisfied for sector change during forward rotation of the
motor
Conditions to be satisfied for sector change during reverse rotation of the
motor
64CEDT, Indian Institute of Science,Bangalore
START
Read Vkα,Vkβ,
Δisα and Δisβ
ComputeVsα and Vsβ
(6) & (7)
IM ParametersLσ and rs
ComputeVa ,Vb and Vc
(11)
ComputeT1 ,T2 and T0
(12)
ComputeΔV1 ,ΔV2 and ΔV0
(13), (14) & (15)
ComputeΔi1 ,Δi2 and Δi0
(16)
Compute orthogonal components of Δi1 ,Δi2 and
Δi0
(Δi1jA ,Δi1jB ,Δi1jC ,Δi2jA ,Δi2jB ,Δi2jC, Δi0jA ,,Δi0jB
and Δi0jC)
Check for Sector change
1
1
Update the sector value
YES
Check for Vector change
NO
StoresVsα , Vsβ,
Present sectorand
Present vector
Stores1. orthogonal components
of Δi1 ,Δi2 and Δi0
2. Actual current errors along orthogonal axes
ΔijA ,ΔijB and ΔijC
3. Previous vector
Actual current errors along
orthogonal axesΔijA ,ΔijB and ΔijC
Update the vector value
YES
END
NO
Previous Vector
Flow Chart for proposed hysteresis controller
65CEDT, Indian Institute of Science,Bangalore
Flow Chart for proposed hysteresis controller
Step 1:Estimate Vs and Vsβ and using zero and active vectors.
Step 2:From Vs and Vsβ , the instantaneous stator phase voltages va, vb & vc are computed.
Step 3:Using the computed values of va, vb & vc, individual vector timings T1, T2 & T0 are calculated.
Step 4:Compute instantaneous voltage error vectors , & are computed.
66CEDT, Indian Institute of Science,Bangalore
1VAAAAAAAAAAAAAA
2VAAAAAAAAAAAAAA
0VAAAAAAAAAAAAAA
Flow Chart for proposed hysteresis controller
Step 5:Compute instantaneous current error vectors , & are computed.Step 6:This current error boundary values Δi1, Δi2 & Δi0 into components along the orthogonal axes jA, jB & jC.Step 7:Check for sector change using estimated Vs and Vsβ.
Step 8:Check whether the current error along the particular orthogonal axis (axis for the present vector along which current error has to be monitored) has crossed the hysteresis boundary computed for Vector change detection.
67CEDT, Indian Institute of Science,Bangalore
1iAAAAAAAAAAAAAA
2iAAAAAAAAAAAAAA
0iAAAAAAAAAAAAAA
Block diagram of proposed hysteresis controller based Inverter fed IM drive
Online computation of current error
boundary
iα and iβ iα* and iβ*
RS, σLS & TS
68CEDT, Indian Institute of Science,Bangalore
Simulation Results
10Hz steady state operation – phase voltage, phase current
10Hz steady state operation – FFT of phase voltage
69CEDT, Indian Institute of Science,Bangalore
Experimental Results
10Hz steady state operation – phase voltage, phase current
10Hz steady state operation – reference current & phase current
70CEDT, Indian Institute of Science,Bangalore
Simulation Results
10Hz steady state operation – Current error space phasor trajectory in sectors 1, 2, 3, one cycle and current space phasor for one cycle
71CEDT, Indian Institute of Science,Bangalore
Experimental Results
10Hz steady state operation – Current error space phasor
trajectory in sectors 1, 2, 3 and one cycle72CEDT, Indian Institute of Science,Bangalore
Simulation Results
10Hz steady state operation – Sector and Vector for one fundamental cycle and zoomed version showing sector-2 and it’s vector switching
73CEDT, Indian Institute of Science,Bangalore
Simulation Results
20Hz steady state operation – phase voltage, phase current
20Hz steady state operation – FFT of phase voltage
74CEDT, Indian Institute of Science,Bangalore
Experimental Results
20Hz steady state operation – phase voltage, phase current
20Hz steady state operation – reference current & phase current
75CEDT, Indian Institute of Science,Bangalore
Simulation Results
20Hz steady state operation – Current error space phasor trajectory in sectors 1, 2, 3, one cycle and current space phasor for one cycle
76CEDT, Indian Institute of Science,Bangalore
Experimental Results
20Hz steady state operation – Current error space phasor trajectory in sectors 1, 2, 3 and one cycle
77CEDT, Indian Institute of Science,Bangalore
Simulation Results
20Hz steady state operation – Sector and Vector for one fundamental cycle and zoomed version showing sector-2 and it’s vector switching
78CEDT, Indian Institute of Science,Bangalore
Simulation Results
40Hz steady state operation – phase voltage, phase current
40Hz steady state operation – FFT of phase voltage
79CEDT, Indian Institute of Science,Bangalore
Experimental Results
40Hz steady state operation – phase voltage, phase current
40Hz steady state operation – reference current & phase current
80CEDT, Indian Institute of Science,Bangalore
Simulation Results
40Hz steady state operation – Current error space phasor trajectory in sectors 1, 2, 3, one cycle and current space phasor for one cycle
81CEDT, Indian Institute of Science,Bangalore
Experimental Results
40Hz steady state operation – Current error space phasor trajectory in sectors 1, 2, 3 and
one cycle
82CEDT, Indian Institute of Science,Bangalore
Simulation Results
47Hz steady state operation – phase voltage, phase current
50Hz steady state operation (six step mode) –phase voltage & phase current
83CEDT, Indian Institute of Science,Bangalore
Experimental Results
50Hz steady state operation (six step mode) –
phase voltage & phase current
84CEDT, Indian Institute of Science,Bangalore
Simulation Results
Acceleration of the IM from standstill to 10Hz in 1 sec.
Speed reversal of the IM from 10Hz to -10Hz
85CEDT, Indian Institute of Science,Bangalore
Experimental Results
Deceleration of the IM from standstill to -10Hz in 1 sec.
Speed reversal of the IM from 10Hz to -10Hz
86CEDT, Indian Institute of Science,Bangalore
Simulation & Experimental Results
Sudden change in Isq at 10Hz – Simulation Results
Sudden change in Isq at 10Hz – Experimental Results
87CEDT, Indian Institute of Science,Bangalore
Simulation Results
Speed reversal of the IM from 20Hz to -20Hz
Sudden change in Isq at 20Hz – Simulation Results
88CEDT, Indian Institute of Science,Bangalore
Experimental Results
Speed reversal of the IM from 20Hz to -20Hz
Sudden change in Isq at 20Hz – Experimental Results
89CEDT, Indian Institute of Science,Bangalore
Simulation Results
Speed reversal of the IM from 40Hz to -40Hz
Sudden change in Isq at 40Hz –
Simulation Results90CEDT, Indian Institute of Science,Bangalore
Experimental Results
Speed reversal of the IM from 40Hz to -40Hz
Sudden change in Isq at 40Hz – Experimental Results
91CEDT, Indian Institute of Science,Bangalore
Salient Features of proposed schemes
PART I Hysteresis controller with parabolic boundary for
vector selection with new sector change detection logic is proposed.
This eliminates outer parabolas used previously for sector change detection.
Proposed scheme gives phase voltage harmonic spectrum similar to that of constant switching frequency SVPWM inverter fed drive.
The proposed controller is taking the drive into over-modulation and six-step mode of operation if demanded by the load.
92CEDT, Indian Institute of Science,Bangalore
Salient Features of proposed schemes
PART II Hysteresis controller with online computation
current error space phasor boundary is proposed for two-level inverter.
It eliminates the look-up table used for implementing the parabolic boundary.
This scheme gives phase voltage harmonic spectrum which is exactly similar to that of constant switching frequency SVPWM inverter.
Boundary is computed using estimated stator voltages along alpha and beta axes during zero and active vectors .
The scheme is modular and can be extended to any n-level multilevel inverter
93CEDT, Indian Institute of Science,Bangalore
Overall Experimental Setup
94CEDT, Indian Institute of Science,Bangalore
Publications1. Rijil Ramchand, P. N. Tekwani, M. R. Baiju and K. Gopakumar,
“An Improved Space Phasor Based Current Hysteresis Controller with Reduced Switching Frequency Variations Using Variable Parabolic Bands”, NPEC-2007, IISc, Bangalore, December 16-19, 2007.
2. Rijil Ramchand, K. Sivakumar, Anandarup Das, Chintan Patel and K. Gopakumar, “A Hysteresis PWM Controller with Constant Switching Frequency for Two-level VSI fed Drives with Operation Extending to the Six-Step Mode”, PCIM Europe-2009 at Nuremberg, May 12-14, 2009.
3. Rijil Ramchand, K. Sivakumar, Anandarup Das, Chintan Patel and K. Gopakumar, “Improved Switching Frequency Variation Control of Hysteresis Controlled VSI Fed IM Drives Using Current Error Space Vector”, IET Power Electronics, vol. 3, no. 2, pp. 219-231, March 2010.
95CEDT, Indian Institute of Science,Bangalore
Publications4. Rijil Ramchand, Chintan Patel, K. Sivakumar, Anandarup Das
and K. Gopakumar, “Online Computation of Hysteresis Boundary from Estimated Stator Voltages during Zero and Active Vector Periods for Constant Switching Frequency Current Error Space Vector Based Hysteresis Controller for VSI fed IM Drives”, Communicated to IEEE Trans. on Power Electronics
5. Rijil Ramchand, Chintan Patel, Anandarup Das, K. Sivakumar, and K.Gopakumar, “A Current Error Space Vector Based Hysteresis Controller with Constant Switching Frequencyand Simple Online boundary Computation for VSI fed IM Drive”, Communicated to IEEE IECON 2010, 7-10 November 2010 at Glendale, AZ, USA.
96CEDT, Indian Institute of Science,Bangalore
97CEDT, Indian Institute of Science,Bangalore