Design and Implementation of a Three Phase Four Wire Shunt Active Power Filter
The purpose of this project is to realize a prototype of 10kVA three phase four wire shunt Active Power Filter
(APF) as a commercial product for Entes Electronics using TMS320F28335 DSP. In APF, the Instantaneous
Power Theory (IPT) based control algorithm and hysteresis band PWM technique is used. PSCAD simulation
model of the APF is constituted. Design, application and simulation studies have been carried on together.
The IPT algorithm uses three phase PCC voltages, load and filter currents in order to calculate gate signals of the
Voltage Source Inverter which provides the current harmonic and reactive power needs of the load. When load
reactive power is compensated and load current harmonics are filtered, the current drawn from the source
reaches sinusoidal shape. Besides, filtering load current harmonics implicitly helps us to lower voltage harmonics
that generated by line impedance. Figure 1 shows the basic compensation principle of the shunt APF and
waveforms. Three phase four wire shunt APF test circuit is shown in Figure 2. For economical and marketing
reasons, the prototype of the shunt APF will be designed only for filtering current harmonics, since shunt APF is
assumed to work together with electronic contactor based compensation system. The object of this approach is to
lower the power levels of the APF equipment. In addition, this prototype is considered the first real-time
application in order to get acquinted with implementation conditions of APF. The hardware list and block diagram
of the system is shown in Figure 3 and 4, consecutively.
Figure 1. Basic Compensation principle of the shunt APF and waveforms
PCC
230
CS
115 115
400
Transformer
SOURCE
ILa
ILb
LOAD
ILc
notr
3 Phase 60A
Fast Fuse
VS
Va Vb Vc
contactors
IFa
Filter Inductor
1mH, 30A
LFa
IFb
LFb
IFc
LFc
CS : Current Sensors :6 X TEG NA50-P
VS: Voltage Sensors :5 X TEG NV25-P
CS
T1
T3
CSdc
4 x Electrolytic Capacitor
4700uF, 450V DC,
18A rms Current Rating
Filter DC Bus
IPM :PM100CL1A120
T5
CSdc
C1DC
CSdc
C2DC
Filter Pre-Charge Unit
2XR 5,6Ω, 50W
T4
T6
S1 S2
Passive Filter
3Ω, 30uF
S3
S4
VS
Vdc1
VS
Vdc2
T2
S5
S6
Snubber Capacitor
220nF, 1200V
Vn1 Vwp1 Vvp1 Vup1
+
+
+
+
Vnc Vwpc Vvpc Vupc
Notr Filter
0.5mH
IGBT Gate Driver Board & Buffer
Load Currents (ILa, ILb,ILc)
Filter Currents (IFa, IFb, IFc)
Source Voltages (Va, Vb, Vc)
+15V
+
-15V
Current – Voltage
Sensor Boards
DSP
TMS320F28335
Figure 2. Three phase four wire shunt APF system block diagram
Prof. Dr. Omer Usta*, Doç. Dr. Engin Ozdemir**, Kahraman Yumak* (PhD Student)
usta@elk.itu.edu.tr, eozdemir@kou.edu.tr, yumakk@itu.edu.tr
*Istanbul Technical University, Electrical Engineering Department, 34469 Maslak, Istanbul, Turkey
**Kocaeli University, Technical Education Faculty, Electrical Education Department 41380, Umuttepe, Turkey.
+15V
+
-15V
DC Bus Voltage
Sensor Board
1.
2.
3.
4.
Digital Signal Processor (TMS320F28335)
IPM Module (Mitsubishi PM100CL1A120)
Semiconductor Fast Fuses
Mains Voltage, Load Currents and APF
Currents Measurement Stage
5. DC Bus Voltage Measurement Stage
6. Load and APF Currents Measurement
Interface Card
7. Mains Voltage Measurement Interface Card
8. 3-Phase Full-Bridge Rectifier Module
9. Load AC Side Filters
10. APF Passive Filters
11. Pre-Charge Resistors
12. Power Supply
Figure 3. Hardware list
LOAD
PCC
3-Phase
AC Utility Grid
Rectifier,
DC Side Inductor,
Capacitor, Resistor
3-Phase
AC Line Reactor
///
///
PAF
Filter Circuit
Breaker
Line Voltage
(v) Sensor
Board
Line Current
(iL ) Sensor
Board
DC Bus
Voltage (Vdc )
Sensor Board
Pre-Charge
Unit
///
Filter Current
(iF ) Sensor
Board
Overcurrent
signal
Passive Filter
Filter Inductor
Signal Conditioning Board
Protection
Board
Disable
Signal
Disable
Signal
Measurement
signals
Voltage
Source
Inverter
IGBT Gate
Driver Board
Circuit Breaker
Driver Board
Electrical Power Circuit
Level Shifter
Board
IGBT
Gate
Signals
Pre-Charge Unit On-Off Signal
Filter Circuit Breaker On-Off Signal
Control Circuit
Figure 4. Block diagram of the shunt APF
Prof. Dr. Omer Usta*, Doç. Dr. Engin Ozdemir**, Kahraman Yumak* (PhD Student)
usta@elk.itu.edu.tr, eozdemir@kou.edu.tr, yumakk@itu.edu.tr
*Istanbul Technical University, Electrical Engineering Department, 34469 Maslak, Istanbul, Turkey
**Kocaeli University, Technical Education Faculty, Electrical Education Department 41380, Umuttepe, Turkey.
DSP unit