𝐂𝐮𝐫𝐫𝐞𝐧𝐭 𝐇𝐚𝐫𝐦𝐨𝐧𝐢𝐜 𝐌𝐢𝐭𝐢𝐠𝐚𝐭𝐢𝐨𝐧 𝐢𝐧 𝐆𝐫𝐢𝐝-𝐓𝐢𝐞𝐝 𝐒𝐨𝐥𝐚𝐫 𝐏𝐕 𝐒𝐲𝐬𝐭𝐞𝐦

𝐂𝐮𝐫𝐫𝐞𝐧𝐭 𝐇𝐚𝐫𝐦𝐨𝐧𝐢𝐜 𝐌𝐢𝐭𝐢𝐠𝐚𝐭𝐢𝐨𝐧 𝐢𝐧 𝐆𝐫𝐢𝐝-𝐓𝐢𝐞𝐝 𝐒𝐨𝐥𝐚𝐫 𝐏𝐕 𝐒𝐲𝐬𝐭𝐞𝐦

𝐈𝐧𝐭𝐫𝐨𝐝𝐮𝐜𝐭𝐢𝐨𝐧

Nonlinear loads can draw highly distorted current from the utility grid. This increases the total harmonic distortion, reduces power quality and may affect other equipment connected at the point of common coupling.

𝐂𝐮𝐫𝐫𝐞𝐧𝐭 𝐇𝐚𝐫𝐦𝐨𝐧𝐢𝐜 𝐌𝐢𝐭𝐢𝐠𝐚𝐭𝐢𝐨𝐧 𝐢𝐧 𝐆𝐫𝐢𝐝-𝐓𝐢𝐞𝐝 𝐒𝐨𝐥𝐚𝐫 𝐏𝐕 𝐒𝐲𝐬𝐭𝐞𝐦

Current Harmonic mitigation in Grid tied Solar PV System

₹9,649.00₹4,824.50

Buy Now

This MATLAB/Simulink model demonstrates current harmonic mitigation in a grid-tied solar PV system using an active current coefficient control strategy.

The proposed system performs three major functions:

• Extracts maximum available power from the solar PV array

• Supplies active and reactive power to the connected load

• Compensates nonlinear-load harmonics to maintain sinusoidal grid current

The model is tested under changing solar irradiance, distorted grid voltage, voltage sag and voltage swell.

𝐖𝐡𝐲 𝐇𝐚𝐫𝐦𝐨𝐧𝐢𝐜 𝐌𝐢𝐭𝐢𝐠𝐚𝐭𝐢𝐨𝐧 𝐈𝐬 𝐑𝐞𝐪𝐮𝐢𝐫𝐞𝐝

A three-phase rectifier with an RL load is used as the nonlinear load. This load draws a nonsinusoidal current and introduces harmonic components into the grid.

Without compensation:

• The grid current becomes distorted

• Current THD may exceed the recommended limit

• Power factor can decrease

• Additional heating may occur in electrical equipment

• Sensitive loads may experience poor operating conditions

In the simulated system, the uncompensated current THD is approximately 22.22%. The grid-connected inverter is therefore controlled to inject the required compensation current.

𝐒𝐲𝐬𝐭𝐞𝐦 𝐎𝐯𝐞𝐫𝐯𝐢𝐞𝐰

The grid-tied solar PV system contains the following major components:

• Solar PV array

• DC–DC boost converter

• Perturb and Observe MPPT controller

• DC-link capacitor

• Three-phase voltage-source inverter

• Coupling inductor

• Nonlinear rectifier load

• Utility grid

• Active current coefficient controller

• Hysteresis current controller

Main system parameters

Parameter	Value
PV modules connected in series	7
Parallel PV strings	12
Rated power of each module	315 W
Voltage at maximum power point	54.7 V
Current at maximum power point	5.76 A
Maximum PV array power	Approximately 26.47 kW
Grid voltage	450 V
Grid frequency	50 Hz
DC-link reference voltage	735 V
Nonlinear-load active power	Approximately 9 kW
Nonlinear-load reactive power	Approximately 5 kVAr
Initial current THD	Approximately 22.22%

𝐒𝐨𝐥𝐚𝐫 𝐏𝐕 𝐀𝐫𝐫𝐚𝐲

The PV array consists of 7 modules in series and 12 strings in parallel. Each module is rated at 315 W.

The PV output changes according to the available solar irradiance.

Solar irradiance	Approximate PV power	PV operating voltage
100 W/m²	2.49 kW	360.9 V
400 W/m²	9–9.5 kW	Approximately 330 V
1000 W/m²	26.47 kW	382.9 V

At approximately 400 W/m², the PV current reaches around 27 A. At 1000 W/m², the current increases to approximately 73 A.

𝐖𝐨𝐫𝐤𝐢𝐧𝐠 𝐏𝐫𝐨𝐜𝐞𝐬𝐬

1. Solar power generation

The PV array converts solar irradiance into DC electrical power. Its voltage and current vary with irradiance and temperature.

2. Maximum power extraction

The measured PV voltage and current are supplied to the Perturb and Observe MPPT controller.

The controller:

• Observes the change in PV voltage

• Observes the change in PV power

• Adjusts the boost-converter duty cycle

• Moves the PV operating point toward maximum power

3. Boost-converter operation

The DC–DC boost converter increases the PV voltage to the required DC-link level.

The MPPT duty cycle is processed through a PWM generator, which controls the converter switch.

4. Grid-connected inverter operation

The voltage-source inverter transfers PV power to the load and utility grid.

It also operates as an active power filter by injecting compensation current for:

• Load-current harmonics

• Load reactive-power demand

• DC-link voltage regulation

5. Grid-current compensation

The controller calculates the required reference current. The inverter then produces the compensation current required to keep the grid current nearly sinusoidal.

𝐂𝐨𝐧𝐭𝐫𝐨𝐥 𝐒𝐭𝐫𝐚𝐭𝐞𝐠𝐲

The inverter is controlled through an active current coefficient control method.

Grid-voltage processing

The measured three-phase grid voltages are processed to obtain clean voltage templates.

The control process includes:

• Converting line-to-line voltage into phase voltage

• Transforming three-phase voltage into stationary components

• Filtering the voltage signals

• Generating three-phase unit vectors

PLL-free synchronization

The system does not depend on a conventional phase-locked loop for synchronization.

Instead, it uses a unit-vector-based synchronization method to generate phase information for all three phases.

This can simplify the synchronization process and support operation under distorted voltage conditions.

Active current coefficient calculation

The three nonlinear-load currents are measured separately.

The controller determines:

• Active current coefficient of phase A

• Active current coefficient of phase B

• Active current coefficient of phase C

• Average active current requirement of the load

The calculated coefficient represents the fundamental active-current component required by the load.

DC-link voltage control

The measured DC-link voltage is compared with the reference value of 735 V.

A PI controller processes the voltage error and determines the additional current required to maintain the DC-link voltage.

Reference-current generation

The load active-current coefficient and DC-link regulation component are combined to produce the total current reference.

The current reference is multiplied by the three-phase unit vectors to obtain phase-wise AC current references.

Hysteresis current control

The reference currents are compared with the measured grid currents.

A hysteresis current controller generates switching pulses for the voltage-source inverter.

The complementary switching signals are used to operate all six inverter switches.

𝐎𝐩𝐞𝐫𝐚𝐭𝐢𝐧𝐠 𝐌𝐨𝐝𝐞𝐬

The system is tested under several operating conditions.

Operating condition	PV contribution	Grid operation	Inverter function
Zero irradiance	No PV power	Supplies load active power	Harmonic and reactive-power compensation
Medium irradiance	Partial PV power	Supplies remaining active power	Supplies PV power and compensation current
High irradiance	PV power exceeds load demand	Receives excess PV power	Supplies load and exports excess power
Distorted grid voltage	Depends on irradiance	Grid voltage contains harmonics	Maintains improved grid-current quality
Voltage sag	Depends on irradiance	Grid voltage decreases	Adjusts current and power exchange
Voltage swell	Depends on irradiance	Grid voltage increases	Regulates current and power exchange

𝐒𝐢𝐦𝐮𝐥𝐚𝐭𝐢𝐨𝐧 𝐑𝐞𝐬𝐮𝐥𝐭𝐬

Case 1: PV irradiance equal to zero

When irradiance is zero, the PV array does not generate power.

Under this condition:

• The utility grid supplies approximately 9 kW of active power

• The nonlinear load consumes approximately 5 kVAr of reactive power

• The inverter supplies the reactive-power requirement

• The inverter compensates harmonic current

• The grid reactive power remains close to zero

• The grid current remains nearly sinusoidal

The voltage-source inverter therefore operates similarly to an active power filter.

Case 2: PV irradiance at 400 W/m²

At 400 W/m², the PV system produces approximately 9–9.5 kW.

The operating response shows that:

• PV power is sufficient to meet most or all of the load’s active-power demand

• The inverter supplies the required active power

• The inverter also supplies the load’s reactive power

• Grid active-power exchange becomes very small

• Grid reactive power remains close to zero

• The nonlinear load current remains distorted

• The grid current remains compensated and nearly sinusoidal

Case 3: PV irradiance at 1000 W/m²

At 1000 W/m², the PV array generates approximately 26.47 kW.

Since the generated PV power is higher than the load demand:

• The inverter supplies the load active power

• The inverter supplies the load reactive power

• The remaining PV power is exported to the utility grid

• Grid-side power factor remains close to unity

• Grid-current waveform quality is maintained

Power-flow summary

Quantity	Approximate value
Load active power	9 kW
Load reactive power	5 kVAr
PV power at 400 W/m²	9–9.5 kW
PV power at 1000 W/m²	26.47 kW
DC-link reference	735 V
Grid reactive power after compensation	Close to zero

Case 4: Distorted grid-voltage condition

Harmonic components are introduced into the grid voltage to evaluate controller performance.

During voltage distortion:

• Grid voltage becomes nonsinusoidal

• The controller continues to calculate the required compensation current

• The inverter supplies load active and reactive power

• Excess PV power is exported to the grid

• Grid reactive power remains close to zero

• Grid-current quality is maintained

This test demonstrates the controller’s ability to operate without conventional PLL-based synchronization.

Case 5: Grid-voltage sag

During a voltage sag, the grid-voltage magnitude is reduced to approximately 0.8 per unit.

The observed response includes:

• Reduced load active-power consumption

• Reduced load reactive-power consumption

• Increased availability of excess PV power

• Increased power export to the utility grid

• Adjustment of grid-current magnitude

• Maintenance of a nearly sinusoidal grid current

Case 6: Grid-voltage swell

During a voltage swell, the grid voltage is increased to approximately 1.2 per unit.

The system response shows:

• Increased active-power demand from the load

• Increased reactive-power demand from the load

• Reduced excess power available for grid export

• Reduced grid-current magnitude

• Continued harmonic-current compensation

• Stable grid-current waveform quality

Voltage disturbance comparison

Condition	Grid-voltage level	Main system response
Normal voltage	1.0 p.u.	Normal power sharing and harmonic compensation
Voltage sag	0.8 p.u.	Increased excess-power export and current adjustment
Voltage swell	1.2 p.u.	Increased load demand and reduced exported power

𝐊𝐞𝐲 𝐅𝐞𝐚𝐭𝐮𝐫𝐞𝐬

• MATLAB/Simulink implementation of a grid-connected PV system

• Current harmonic mitigation for a nonlinear rectifier load

• Active current coefficient control method

• PLL-free unit-vector synchronization

• Perturb and Observe MPPT control

• Boost-converter duty-cycle control

• DC-link voltage regulation

• Hysteresis current control

• Reactive-power compensation

• Unity power-factor operation at the grid side

• Active-power import and export

• Operation under changing solar irradiance

• Performance testing under voltage distortion

• Voltage-sag and voltage-swell analysis

• Detailed grid, load, inverter and PV waveforms

  
  

𝐀𝐝𝐯𝐚𝐧𝐭𝐚𝐠𝐞𝐬

• Improves grid-current waveform quality

• Reduces the effect of nonlinear-load harmonics

• Compensates load reactive power

• Utilizes the PV inverter for multiple functions

• Supports bidirectional active-power flow with the utility grid

• Maintains near-unity grid-side power factor

• Operates under variable solar irradiance

• Provides stable performance during grid-voltage disturbances

• Avoids dependency on a conventional PLL

• Demonstrates coordinated power-quality and renewable-energy control

  
  

𝐀𝐩𝐩𝐥𝐢𝐜𝐚𝐭𝐢𝐨𝐧𝐬

This model is useful for studying:

• Grid-connected solar PV systems

• Harmonic compensation techniques

• Active power filtering

• Nonlinear-load compensation

• Renewable-energy power-quality improvement

• Distribution-system power conditioning

• Grid-current control

• Reactive-power compensation

• MPPT-based PV energy conversion

• Voltage sag and swell performance

• PLL-free grid synchronization

• Smart-grid power-flow management

  
  

𝐖𝐡𝐨 𝐂𝐚𝐧 𝐔𝐬𝐞 𝐓𝐡𝐢𝐬 𝐌𝐨𝐝𝐞𝐥?

The simulation is suitable for:

• Electrical engineering students

• Power electronics learners

• Renewable-energy researchers

• MATLAB/Simulink users

• Power-quality engineers

• Grid-integration specialists

• Engineers studying nonlinear-load compensation

  
  

𝐋𝐞𝐚𝐫𝐧𝐢𝐧𝐠 𝐎𝐮𝐭𝐜𝐨𝐦𝐞𝐬

By studying this system, users can understand:

• How nonlinear loads create current harmonics

• How a PV inverter can operate as an active power filter

• How MPPT extracts maximum power from a PV array

• How active and reactive power are shared among the PV system, load and grid

• How reference currents are produced for the inverter

• How hysteresis current control generates inverter switching pulses

• How grid-current quality is maintained during voltage disturbances

• How excess solar power is exported to the utility grid

  
  

𝐂𝐨𝐧𝐜𝐥𝐮𝐬𝐢𝐨𝐧

The Current Harmonic Mitigation in Grid-Tied Solar PV System model demonstrates an effective method for combining renewable-energy conversion with power-quality improvement.

The nonlinear rectifier load produces highly distorted current with an initial THD of approximately 22.22%. The active current coefficient controller calculates the fundamental active-current requirement and generates suitable reference currents for the grid-connected inverter.

When solar irradiance is unavailable, the inverter operates as an active power filter and compensates the load’s harmonics and reactive power. At medium irradiance, PV power supplies the load and reduces power drawn from the grid. At high irradiance, the PV system supplies the load and exports excess active power to the utility grid.

The simulation also demonstrates stable operation under distorted grid voltage, voltage sag and voltage swell. Throughout these conditions, the inverter supports reactive-power compensation, power-flow control and improved grid-current quality.

This MATLAB/Simulink model provides a practical learning platform for understanding solar PV control, harmonic mitigation, MPPT, active filtering, grid synchronization and power-quality enhancement.