𝐔𝐏𝐐𝐂 𝐂𝐨𝐧𝐭𝐫𝐨𝐥 𝐂𝐨𝐦𝐩𝐚𝐫𝐢𝐬𝐨𝐧 𝐔𝐬𝐢𝐧𝐠 𝐃𝐐𝟎 𝐚𝐧𝐝 𝐏𝐐 𝐓𝐡𝐞𝐨𝐫𝐲 𝐢𝐧 𝐌𝐀𝐓𝐋𝐀𝐁/𝐒𝐢𝐦𝐮𝐥𝐢𝐧𝐤

𝐔𝐏𝐐𝐂 𝐂𝐨𝐧𝐭𝐫𝐨𝐥 𝐂𝐨𝐦𝐩𝐚𝐫𝐢𝐬𝐨𝐧 𝐔𝐬𝐢𝐧𝐠 𝐃𝐐𝟎 𝐚𝐧𝐝 𝐏𝐐 𝐓𝐡𝐞𝐨𝐫𝐲 𝐢𝐧 𝐌𝐀𝐓𝐋𝐀𝐁

𝐈𝐧𝐭𝐫𝐨𝐝𝐮𝐜𝐭𝐢𝐨𝐧

𝐔𝐏𝐐𝐂 𝐂𝐨𝐧𝐭𝐫𝐨𝐥 𝐂𝐨𝐦𝐩𝐚𝐫𝐢𝐬𝐨𝐧 𝐔𝐬𝐢𝐧𝐠 𝐃𝐐𝟎 𝐚𝐧𝐝 𝐏𝐐 𝐓𝐡𝐞𝐨𝐫𝐲, is an advanced power electronics system used to improve power quality in electrical distribution networks. This MATLAB/Simulink model compares two control strategies for UPQC operation under voltage sag, voltage swell, and harmonic disturbance conditions.

The model is useful for understanding how 𝐬𝐞𝐫𝐢𝐞𝐬 𝐚𝐜𝐭𝐢𝐯𝐞 𝐩𝐨𝐰𝐞𝐫 𝐟𝐢𝐥𝐭𝐞𝐫 and 𝐬𝐡𝐮𝐧𝐭 𝐚𝐜𝐭𝐢𝐯𝐞 𝐩𝐨𝐰𝐞𝐫 𝐟𝐢𝐥𝐭𝐞𝐫 work together to maintain clean voltage and sinusoidal source current.

𝐒𝐲𝐬𝐭𝐞𝐦 𝐎𝐯𝐞𝐫𝐯𝐢𝐞𝐰

The UPQC system is designed with a grid source, nonlinear load, series active filter, shunt active filter, injecting transformer, and voltage source inverters. The main aim is to reduce voltage and current distortion during abnormal grid conditions.

𝐏𝐚𝐫𝐚𝐦𝐞𝐭𝐞𝐫	𝐕𝐚𝐥𝐮𝐞 / 𝐃𝐞𝐭𝐚𝐢𝐥
Simulation Platform	MATLAB/Simulink
System Type	UPQC Power Quality Improvement System
Grid Voltage	400 V
Grid Frequency	50 Hz
Disturbance Type	Harmonics, Voltage Sag, Voltage Swell
Load Type	Nonlinear Load
Series Filter Function	Voltage disturbance compensation
Shunt Filter Function	Source current harmonic compensation

𝐖𝐨𝐫𝐤𝐢𝐧𝐠 𝐏𝐫𝐨𝐜𝐞𝐬𝐬

The system creates practical power quality disturbances in the grid side and checks how UPQC improves the output response.

𝐂𝐨𝐧𝐝𝐢𝐭𝐢𝐨𝐧	𝐎𝐩𝐞𝐫𝐚𝐭𝐢𝐨𝐧
Normal Condition	Source current is maintained nearly sinusoidal
Harmonic Injection	5th and 7th harmonics are added to the grid voltage
Voltage Sag	UPQC injects required voltage to support load voltage
Voltage Swell	UPQC compensates excess voltage and maintains load voltage
Nonlinear Load	Creates current harmonics, controlled by shunt filter

𝐂𝐨𝐧𝐭𝐫𝐨𝐥 𝐒𝐭𝐫𝐚𝐭𝐞𝐠𝐲

Two UPQC control combinations are compared in this model.

𝐌𝐞𝐭𝐡𝐨𝐝	𝐒𝐞𝐫𝐢𝐞𝐬 𝐀𝐜𝐭𝐢𝐯𝐞 𝐅𝐢𝐥𝐭𝐞𝐫	𝐒𝐡𝐮𝐧𝐭 𝐀𝐜𝐭𝐢𝐯𝐞 𝐅𝐢𝐥𝐭𝐞𝐫
Method 1	DQ0 Control	PQ Theory Control
Method 2	DQ0 Control	DQ0 Control

𝐃𝐐𝟎 𝐂𝐨𝐧𝐭𝐫𝐨𝐥

• Converts three-phase voltage or current into DQ0 frame• Helps generate accurate reference signals• Used for voltage compensation in the series active filter• Also used for current compensation in the shunt filter in the second method

𝐏𝐐 𝐓𝐡𝐞𝐨𝐫𝐲 𝐂𝐨𝐧𝐭𝐫𝐨𝐥

• Calculates active and reactive power components• Generates reference current for harmonic compensation• Used in the shunt active filter in the first method• Suitable for understanding instantaneous power-based compensation

𝐒𝐢𝐦𝐮𝐥𝐚𝐭𝐢𝐨𝐧 𝐑𝐞𝐬𝐮𝐥𝐭𝐬

The simulation results show that both control methods improve power quality. However, the DQ0 control method for both series and shunt active filters gives better source current harmonic reduction.

𝐂𝐨𝐧𝐭𝐫𝐨𝐥 𝐌𝐞𝐭𝐡𝐨𝐝	𝐎𝐩𝐞𝐫𝐚𝐭𝐢𝐧𝐠 𝐂𝐨𝐧𝐝𝐢𝐭𝐢𝐨𝐧	𝐓𝐇𝐃 𝐑𝐞𝐬𝐮𝐥𝐭
DQ0 + PQ	Load Voltage during Harmonic Condition	Around 1.98%
DQ0 + PQ	Source Current during Harmonic Condition	Around 20.36%
DQ0 + PQ	Load Voltage during Sag	Around 1%
DQ0 + PQ	Load Voltage during Swell	Around 2.91%
DQ0 + DQ0	Load Voltage during Harmonic Condition	Around 4.26%
DQ0 + DQ0	Load Voltage during Sag	Around 0.94%
DQ0 + DQ0	Load Voltage during Swell	Around 2.83%
DQ0 + DQ0	Source Current during Harmonic Condition	Around 0.14%
DQ0 + DQ0	Source Current during Sag	Around 0.16%
DQ0 + DQ0	Source Current during Swell	Around 0.23%

𝐂𝐨𝐦𝐩𝐚𝐫𝐢𝐬𝐨𝐧 𝐒𝐮𝐦𝐦𝐚𝐫𝐲

𝐅𝐞𝐚𝐭𝐮𝐫𝐞	𝐃𝐐𝟎 + 𝐏𝐐 𝐂𝐨𝐧𝐭𝐫𝐨𝐥	𝐃𝐐𝟎 + 𝐃𝐐𝟎 𝐂𝐨𝐧𝐭𝐫𝐨𝐥
Voltage Sag Compensation	Good	Good
Voltage Swell Compensation	Good	Good
Load Voltage THD	Less than 5%	Less than 5%
Source Current THD during Harmonic Condition	Higher	Very Low
Current Waveform Quality	Moderate during harmonic disturbance	Better sinusoidal nature
Overall Performance	Acceptable	Better

𝐊𝐞𝐲 𝐅𝐞𝐚𝐭𝐮𝐫𝐞𝐬

• Complete 𝐔𝐏𝐐𝐂 model developed in MATLAB/Simulink• Comparison of 𝐃𝐐𝟎 𝐚𝐧𝐝 𝐏𝐐 𝐭𝐡𝐞𝐨𝐫𝐲 based control methods• Analysis under voltage sag, voltage swell, and harmonic conditions• FFT-based THD analysis included• Helps to understand series and shunt active filter operation• Suitable for power quality and power electronics learning• Clean simulation workflow for engineers and researchers

𝐀𝐩𝐥𝐢𝐜𝐚𝐭𝐢𝐨𝐧𝐬

• Power quality improvement in distribution systems• Harmonic mitigation in nonlinear load environments• Voltage sag and swell compensation• Active power filter control study• MATLAB/Simulink-based power electronics analysis• Renewable energy grid interface studies• Industrial load compensation studies

𝐖𝐡𝐲 𝐓𝐡𝐢𝐬 𝐌𝐨𝐝𝐞𝐥 𝐢𝐬 𝐔𝐬𝐞𝐟𝐮𝐥

This model gives a clear comparison between two popular UPQC control approaches. Students can understand the basic control structure, researchers can analyze THD improvement, and engineers can study how UPQC supports voltage and current quality during grid disturbances.

The simulation also shows that choosing the right control method is important for improving source current waveform quality and reducing harmonic distortion.

𝐂𝐨𝐧𝐜𝐥𝐮𝐬𝐢𝐨𝐧

The UPQC control comparison using 𝐃𝐐𝟎 and 𝐏𝐐 theory in MATLAB/Simulink clearly shows the importance of advanced control methods in power quality improvement. Both methods compensate voltage sag, voltage swell, and load voltage harmonics effectively. However, the 𝐃𝐐𝟎–𝐃𝐐𝟎 control method provides better source current harmonic reduction, especially during harmonic disturbance conditions.

This model is highly useful for learning UPQC operation, active filter control, THD analysis, and power quality enhancement in modern electrical systems.