Hello everyone,
I’m working on a Two-Level Active Front-End (AFE) converter model in Simulink. The simulation runs successfully when the load is a battery, but I’m facing issues when I replace the battery with a resistive load.
❗ Issues Encountered:
The control becomes unstable or fails when switching to a resistive load.
I’m using a SOGI-based PLL for synchronization and sequence extraction.
Under balanced input voltage conditions, I’m observing a non-zero negative-sequence Vd (~1.5 V), which ideally should be near zero.
📌 System Configuration:
Two-Level Voltage Source Converter (VSC)
RC-damped LCL Filter
SOGI-based sequence extraction and PLL
dq frame current control
Battery load: DC voltage source
Resistive load: Fixed resistor connected across DC bus

✅ My Questions:
Why does the system behave well with a battery load, but not with a resistive load?
What could cause a non-zero negative-sequence Vd (~1.5 V) under balanced conditions?
How should I tune the SOGI filter or control loops to improve stability and accuracy during resistive loading?
If needed, I can provide block diagrams or simulation waveforms. Any insights or similar experiences would be very helpful.
Thanks in advance,
Thangamuthu NHello everyone,
I’m working on a Two-Level Active Front-End (AFE) converter model in Simulink. The simulation runs successfully when the load is a battery, but I’m facing issues when I replace the battery with a resistive load.
❗ Issues Encountered:
The control becomes unstable or fails when switching to a resistive load.
I’m using a SOGI-based PLL for synchronization and sequence extraction.
Under balanced input voltage conditions, I’m observing a non-zero negative-sequence Vd (~1.5 V), which ideally should be near zero.
📌 System Configuration:
Two-Level Voltage Source Converter (VSC)
RC-damped LCL Filter
SOGI-based sequence extraction and PLL
dq frame current control
Battery load: DC voltage source
Resistive load: Fixed resistor connected across DC bus

✅ My Questions:
Why does the system behave well with a battery load, but not with a resistive load?
What could cause a non-zero negative-sequence Vd (~1.5 V) under balanced conditions?
How should I tune the SOGI filter or control loops to improve stability and accuracy during resistive loading?
If needed, I can provide block diagrams or simulation waveforms. Any insights or similar experiences would be very helpful.
Thanks in advance,
Thangamuthu N Hello everyone,
I’m working on a Two-Level Active Front-End (AFE) converter model in Simulink. The simulation runs successfully when the load is a battery, but I’m facing issues when I replace the battery with a resistive load.
❗ Issues Encountered:
The control becomes unstable or fails when switching to a resistive load.
I’m using a SOGI-based PLL for synchronization and sequence extraction.
Under balanced input voltage conditions, I’m observing a non-zero negative-sequence Vd (~1.5 V), which ideally should be near zero.
📌 System Configuration:
Two-Level Voltage Source Converter (VSC)
RC-damped LCL Filter
SOGI-based sequence extraction and PLL
dq frame current control
Battery load: DC voltage source
Resistive load: Fixed resistor connected across DC bus

✅ My Questions:
Why does the system behave well with a battery load, but not with a resistive load?
What could cause a non-zero negative-sequence Vd (~1.5 V) under balanced conditions?
How should I tune the SOGI filter or control loops to improve stability and accuracy during resistive loading?
If needed, I can provide block diagrams or simulation waveforms. Any insights or similar experiences would be very helpful.
Thanks in advance,
Thangamuthu N simulink, model, converter, battery, resistive load MATLAB Answers — New Questions

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