Design and testing of an on-grid power converter used to connect a variable speed low voltage generator

The motivation of this research arises from the design of a low scale electric generation project, where a poly-phase generator is designed to harvest the energy from static exercise machines. This article presents the development of a static power electronics scheme based on a rectifier, dc-dc converter and a voltage source inverter (VSI) that enables the efficient energy management between a variable speed low voltage generator and the residential grid. The converter topology developed here incorporates an uncontrolled rectifier bridge, dc-dc boost converter, 400V dc-link capacitor, single-phase full bridge inverter and LC passive filter on-grid connected. The inverter control model developed here is based on a reference framework, synchronized with single-phase grid voltage, controlling the injection of grid current in direct and quadrature axis model, which allows for reactive power control in single-phase system. The direct current component is used in an internal dc-link voltage control loop. This dq control strategy makes the ac current signal formation possible with the right frequency, amplitude and angular phase in order to inject the power provided by the generator quickly and efficiently to the static converter.