Single-phase grid-connected distributed generation system with Maximum Power Tracking

The paper presents a single-phase grid-connected generation plant consisting of a prime mover driving a three-phase squirrel cage Induction Generator (IG) and a back-to-back voltage source PulseWidth Modulation (PWM) power converter. The prime mover is a commercial Internal Combustion Engine (ICE) whose speed is controlled through a Controller Area Network (CAN) bus protocol. The IG control uses a Direct Rotor Field Oriented Control (DRFOC) approach that employs a Maximum Power Point Tracking (MPPT) scheme to maximize the power generated by the IG for a given generator phase current. A single-phase PWM converter interfaces the generation plant with the electrical power grid. The grid-side converter control is insensitive to distorted grid voltage and to the intrinsic (natural for single-phase converters) DC-link second order harmonic ripple, keeping the injected current sinusoidal. The whole control algorithm is implemented on a fast prototyping dSPACE modular system based on the DS1005 processor board. Experimental tests have been obtained on a generation prototype for steady state and transient operating condition

Enhanced power quality control strategy for Single-Phase Inverters in Distributed generation systems

Power electronic converters are commonly used for interfacing distributed generation (DG) systems to the electrical power network. This paper deals with a single-phase inverter for DG systems requiring power quality features, such as harmonic and reactive power compensation for grid-connected operation. The idea is to integrate the DG unit functions with shunt active power filter capabilities. With this approach, the inverter controls the active power flow from the renewable energy source to the grid and also performs the nonlinear load current harmonic compensation by keeping the grid current almost sinusoidal. The control scheme employs a current reference generator based on sinusoidal signal integrator and instantaneous reactive power (IRP) theory together with a dedicated repetitive current controller. Experimental results obtained on a 4-kVA inverter prototype demonstrate the feasibility of the proposed solutio