What are the design guidelines for parallel grid connected inverters?

Three parallel grid-connected inverters are considered as a case study. Then, the control system design guidelines are suggested based on multivariable control theory with considering the proposed grid voltage feedforward method and coupling effect among inverters.

What is a grid connected inverter?

Grid-connected inverters are essential elements in converting nearly all kinds of generated power in distributed generation plants into a high quality AC power to be injected reliably into the grid . The quality of grid injected current in grid-connected systems is a matter of concern .

What is grid-connected current of inverters in parallel operation?

Hou et al. point out that the grid-connected current of inverters in parallel operation consists of three parts, namely the average current, ZSCC and differential circulating current and a decomposed current control scheme is proposed to minimise the differential current from equivalent circuit models.

Can a single-phase inverter parallel system be used for grid-connected power generation systems?

In order to solve the above problems, this paper designs a single-phase inverter parallel system that can be used for grid-connected power generation systems. The system uses TMS320F28379D as the control core, adopts DC-AC conversion strategy, and the main inverter topology is a full-bridge inverter circuit.

Why is a single grid connected inverter instable?

For single grid-connected inverter, despite good performance, the system tends to become instable with parallel connection of other inverters. Moreover, the grid injected current can be distorted by the grid voltage harmonics.

What is a three-phase grid-connected inverter system?

In this paper, a new three-phase grid-connected inverter system is proposed. The proposed system includes two inverters. The main inverter, which operates at a low switching frequency, transfers active power to the grid. The auxiliary inverter processes a very low power to compensate for the grid current ripple.