Discrete Time Domain Modeling and Control of a Grid-Connected Four-Wire Split-Link Converter

Distributed generation (DG) allows the production of renewable energy where it is consumed, avoiding transport losses. It envisioned that future DG units will become more intelligent, not just injecting power into grid but also actively improving quality by means active filtering techniques. In this manner, voltage and current harmonics, unbalance or over-voltages can be mitigated. To achieve such a smart unit, an appropriate multi-functional converter topology required, with full control over currents exchanged grid, including neutral-wire current. For purpose, article studies three-phase four-wire split-link converter. A known problem bus capacitors. This mid-point balanced either additional zero-sequence which return through neutral wire, compensating half-bridge chopper. both methods, presents discrete time domain model to allow controller design implementation in digital control. Both techniques are validated compared simulation results experiments on test setup.