Power Control in Andronov-Hopf Virtual Oscillator Converters for ST-Based LV Distribution Systems

Today’s distribution grid faces challenges in maintaining power flow and power quality due to the increasing integration of distributed generation (DG) units. The smart transformer (ST) is an effective solution to overcome these challenges by employing accurate control of both active and reactive power flows. Generally, the low-voltage (LV) converter of ST is controlled using a voltage-oriented control strategy, often facing issues with integral saturation and difficult parameter adjustment. Meanwhile, the DG converters operate in the current control mode, which leads to reduced system stability and poor synchronization, particularly during transient events and weak grid scenarios. To overcome these issues, this article proposes a novel Andronov–Hopf oscillator (AHO) circuit-based virtual oscillator (VO) control for the ST LV converter and DG converters in the ST-based converter-dominated LV distribution systems. This approach allows for simultaneous active and reactive power control of AHO-controlled LV DG converters, with the ST LV converter operating as a slack unit. Additionally, two integral control laws are incorporated to counter the remaining steady-state power errors caused by system uncertainties. The proposed control strategy is simulated in MATLAB/Simulink software and experimentally validated through a power-hardware-in-loop (PHIL) test bench.