Background:
Aiming at the three-phase voltage source PWM rectifier (VSR), there
have been some researches on the neural network control strategies, but the unbalanced power grid
condition is always neglected. Meanwhile, about the self-detection technology of the unbalanced
power grid voltage, there are still few researches.
Methods:
Under the unbalanced power grid conditions, this work presents a power grid voltage
sensorless control strategy of the three-phase VSR. Based on the radial basis function neural network
(RBF) theory, a newly PI controller with parameter self-tuning function is studied, and the
RBF-PI controller is used for the closed-loop controls of the voltage and current variables. By
means of T/4 delay method, the positive- and negative-sequence components of the power grid side
current, and those of the equivalent virtual flux-linkage of unbalanced power grid are extracted.
From the equivalent virtual flux-linkage, the unbalanced power grid voltage is reconstructed
online.
Results:
Under the load mutation condition, the power grid voltage sensorless control of threephase
VSR is achieved, the system response characteristics are analyzed. From the simulation experimental
results, it can be seen that the unbalanced power grid voltage can be quickly tracked,
and the sinusoidal control of the power grid side current can be achieved. In addition, the control
system has a series of advantages, such as a faster dynamic response speed, a stronger robustness
and a smaller DC side voltage ripple.
Conclusion:
The proposed unbalanced power grid voltage sensorless control strategy of threephase
VSR is effective.
One-Cycle Control Strategy for Dual-Converter Three-Phase PWM Rectifier under Unbalanced Grid Voltage Conditions