Harmonic voltage resonant compensation control of a three-phase inverter for battery energy storage systems applied in isolated microgrid

• A comprehensive model of the inverter combining multiple resonant controllers is established.
• The parameters are optimally determined via the optimal linear-quadratic theory.
• The harmonics voltage was eliminated through the proposed control algorithm.
• The BESS with the control algorithm perfectly supports the operation of island microgrid.

The aim of this paper is to propose a sinusoidal voltage signals tracking control strategy, adaptive for frequency of a three-phase inverter for a battery energy storage system (BESS) applied to an isolated microgrid. To support the normal operation of distributed renewable energy and feed the critical loads under the isolated mode, the BESS generally works in voltage control mode (VCM). The proposed control strategy, which transforms the tracking control problem into a state feedback control problem, includes two terms, one of which is state feedback control used to stabilize system while another employs multiple resonant controllers applied to achieve harmonics compensation control. The optimal linear-quadratic (LQ) control approach in which the root locus method is used for optimization selection of weight matrix Q is adopted to tune the control parameters of multiple resonant controllers. The proposed control strategy performs outstanding voltage control performance to maintain an excellent voltage level such as zero steady-state error and low total harmonic distortion (THD) under the situation of sudden load changes, back power flow of renewable energy such as photovoltaic and nonlinear load in an isolated microgrid. Finally, the validity of the proposed approach is verified through simulations and a three-phase experiment prototype of BESS with TMS320F28335 DSP.