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 Pulse Width 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 conditions.