ECEN 613
Rectifier & Inverter Circuits
Module-7c
Professor:
Dr. P. Enjeti with Michael T. Daniel
Rm. 024, WEB
Email: enjeti@tamu.edu
michael.t.daniel@tamu.edu
Textbook:
Power Electronics – Converters,
Applications & Design (Third edition),
by: Ned Mohan et al., John Wiley
COURSE WEBPAGE: http://eCampus.tamu.edu
ECEN 613
Rectifiers & Inverters
Dr. Prasad Enjeti, Department of Electrical & Computer Engineering, Texas A&M University
http://www.ece.tamu.edu/People/bios/benjetip.html
1
Chapter 18
Utility Interface
ECEN 613
Rectifiers & Inverters
Dr. Prasad Enjeti, Department of Electrical & Computer Engineering, Texas A&M University
http://enjeti.tamu.edu
2
PWM Rectifiers: 1-Phase Voltage Source – Example
The PWM rectifier shown in the top figure is employed for managing power flow
between an electric vehicle and the grid. The equivalent circuit is shown in the
bottom figure. The converter can draw power (Watts) from the grid to charge the
a
vehicle or draw power from the vehicle and feed it to the grid. It can also supply
+
reactive power (VARs) to the grid.
Vs
The input voltage VS can be either 120 Vrms or 220 Vrms, at 60Hz. When Vs = 120 Vrms
the charging / discharging rate is 100W ≤ P ≤ 1 kW. When Vs = 220 Vrms the charging
/ discharging rate is 100W ≤ P ≤ 3 kW. When the vehicle is charging or discharging it is
required to maintain unity PF. Xs is 0.1 p.u. given Vbase = √2*220 Vrms and Pbase = 3 kW.
Xs
-
+
VAO
-
+
A
Vdc
-
O
Xs
Vs 0o
VAO,1 δo
(a) When Vs = 120 Vrms, find the minimum Vdc to exchange 1 kW with the grid. Assume m = 1.
(b) When Vs = 120 Vrms, find δ to charge the vehicle at 1 kW.
(c) When Vs = 120 Vrms, find δ to supply 500 W to the grid from the vehicle.
(d) When Vs = 220 Vrms, find the minimum Vdc to exchange 3 kW with the grid. Assume m = 1.
ECEN 613
Rectifiers & Inverters
Dr. Prasad Enjeti, Department of Electrical & Computer Engineering, Texas A&M University
http://enjeti.tamu.edu
3
PWM Rectifiers: 1-Phase Voltage Source – Example
a
Xs
+
+
Vs
-
+
A
Vdc
VAO
-
O
-
Xs
Vs 0o
ECEN 613
Rectifiers & Inverters
Dr. Prasad Enjeti, Department of Electrical & Computer Engineering, Texas A&M University
http://enjeti.tamu.edu
VAO,1 δo
4
PWM Rectifiers: 1-Phase Voltage Source – Example
a
Xs
+
+
Vs
-
+
A
Vdc
VAO
-
O
-
Xs
Vs 0o
ECEN 613
Rectifiers & Inverters
Dr. Prasad Enjeti, Department of Electrical & Computer Engineering, Texas A&M University
http://enjeti.tamu.edu
VAO,1 δo
5
PWM Rectifiers: 1-Phase Voltage Source – Example
a
Xs
+
+
Vs
-
+
A
Vdc
VAO
-
O
-
Xs
Vs 0o
ECEN 613
Rectifiers & Inverters
Dr. Prasad Enjeti, Department of Electrical & Computer Engineering, Texas A&M University
http://enjeti.tamu.edu
VAO,1 δo
6
PWM Rectifiers: 1-Phase Voltage Source – Example
a
Xs
+
+
Vs
-
+
A
Vdc
VAO
-
O
-
Xs
Vs 0o
ECEN 613
Rectifiers & Inverters
Dr. Prasad Enjeti, Department of Electrical & Computer Engineering, Texas A&M University
http://enjeti.tamu.edu
VAO,1 δo
7
PWM Rectifiers: 1-Phase Voltage Source – Example
a
Xs
+
+
Vs
-
+
A
Vdc
VAO
-
O
-
Xs
Vs 0o
ECEN 613
Rectifiers & Inverters
Dr. Prasad Enjeti, Department of Electrical & Computer Engineering, Texas A&M University
http://enjeti.tamu.edu
VAO,1 δo
8
PWM Rectifiers: 1-Phase Voltage Source – Example
a
Xs
+
+
Vs
-
+
A
Vdc
VAO
-
O
-
Xs
Vs 0o
ECEN 613
Rectifiers & Inverters
Dr. Prasad Enjeti, Department of Electrical & Computer Engineering, Texas A&M University
http://enjeti.tamu.edu
VAO,1 δo
9
PWM Rectifiers: 1-Phase Voltage Source – Example
a
Xs
+
+
Vs
-
+
A
Vdc
VAO
-
O
-
Xs
Vs 0o
ECEN 613
Rectifiers & Inverters
Dr. Prasad Enjeti, Department of Electrical & Computer Engineering, Texas A&M University
http://enjeti.tamu.edu
VAO,1 δo
10
PWM Rectifiers: 1-Phase Voltage Source – Example
(e) During the night when the vehicle does not need to charge and
the grid does not require additional real power, it is desired that the
converter supply reactive power to the grid. Assume the DC voltage
is increased to 600 Vdc. If Vs = 120 Vrms with this Vdc, what is the
maximum amount of capacitive reactive power that the converter
can supply to the grid?
a
Xs
+
+
Vs
-
(g) What value would we need to select for each parameter to supply
only ¼ of the reactive power found in part (e)?
O
-
Xs
Vs 0o
Rectifiers & Inverters
Vdc
VAO
-
(f) If we need to supply less reactive power than the maximum found
in part (e) what are two parameters that we could use to reduce the
amount of reactive power supplied
ECEN 613
+
A
Dr. Prasad Enjeti, Department of Electrical & Computer Engineering, Texas A&M University
http://enjeti.tamu.edu
VAO,1 δo
11
a
Xs
+
Vs
-
ECEN 613
Rectifiers & Inverters
Dr. Prasad Enjeti, Department of Electrical & Computer Engineering, Texas A&M University
http://enjeti.tamu.edu
+
VAO
-
+
A
Vdc
O
-
12
PWM Rectifiers: 1-Phase Voltage Source – Example
a
Xs
+
+
Vs
-
+
A
Vdc
VAO
-
O
-
Xs
Vs 0o
ECEN 613
Rectifiers & Inverters
Dr. Prasad Enjeti, Department of Electrical & Computer Engineering, Texas A&M University
http://enjeti.tamu.edu
VAO,1 δo
13
PWM Rectifiers: 1-Phase Voltage Source – Example
a
Xs
+
+
Vs
-
+
A
Vdc
VAO
-
O
-
Xs
Vs 0o
ECEN 613
Rectifiers & Inverters
Dr. Prasad Enjeti, Department of Electrical & Computer Engineering, Texas A&M University
http://enjeti.tamu.edu
VAO,1 δo
14
PWM Rectifiers: 3-phase Voltage Source - Operation Analysis
• Inductor limits the harmonics in the input current due to PWM switching
• VAO,1 magnitude and phase angle
ECEN 613
Rectifiers & Inverters
can be adjusted to control the direction of power flow
Dr. Prasad Enjeti, Department of Electrical & Computer Engineering, Texas A&M University
http://enjeti.tamu.edu
PWM Rectifiers: 3-phase Voltage Source - Operation Analysis
Design Example:
ECEN 613
Rectifiers & Inverters
Dr. Prasad Enjeti, Department of Electrical & Computer Engineering, Texas A&M University
http://enjeti.tamu.edu
PWM Rectifiers: 3-phase Voltage Source: Closed loop Control
 Vs ⋅ E a ,1 
 ⋅ sin(δ )
P = 
 Xs 
2
Q=
Vs
Xs
 Ea ,1

1 −
⋅ cos(δ ) 
Vs


Control of Three Phase PWM Rectifier/Inverter
The most popular control algorithm for three
phase PWM rectifier/inverter is known as
Current Control (CC). This algorithm calculates
reference currents needed to satisfy reference
dc-link voltage as well as zero reactive power
transfer. Then line currents are controlled
corresponding to reference currents through
closed loop current regulators. Advantages of
current control include – utilize space vector
PWM, minimize switching loss, and reduce
current ripple due to high switching frequency.
ECEN 613
Rectifiers & Inverters
ω
Dr. Prasad Enjeti, Department of Electrical & Computer Engineering, Texas A&M University
http://enjeti.tamu.edu
ω
17
PWM Rectifiers: 1-phase Voltage doubler configuration
• 1-phase UPS – with LV and HV battery
• 1-phase to 3-phase Converter
ECEN 613
Rectifiers & Inverters
Dr. Prasad Enjeti, Department of Electrical & Computer Engineering, Texas A&M University
http://enjeti.tamu.edu
18
ECEN 613
Rectifiers & Inverters
Dr. Prasad Enjeti, Department of Electrical & Computer Engineering, Texas A&M University
http://enjeti.tamu.edu
19
PWM Rectifiers: 1-phase UPS configuration
ECEN 613
Rectifiers & Inverters
Dr. Prasad Enjeti, Department of Electrical & Computer Engineering, Texas A&M University
http://enjeti.tamu.edu
20
PWM Rectifier - Static VAR Compensator
ECEN 613
Rectifiers & Inverters
Dr. Prasad Enjeti, Department of Electrical & Computer Engineering, Texas A&M University
http://enjeti.tamu.edu
21