A Novel Controller for Power Decoupling in a Single-Phase Grid-Tied Inverter Using a Boost Converter Buffer

摘要

The de source in a standard single-phase dc:ac inverter experiences significant ripple current due to pulsations in the instantaneous power of the ac sink. Maintaining a constant dC bus in the presence of this ripple typically requires either a large bus capacitance, which is costly and will be highly stressed, or some additional circuitry to act as an energy buffer. In this work a buffer is proposed which consists of a boost converter in parallel with the single-phase grid-tied inverter. An instantaneous ripple current is calculated using information from the inverter controller, and a negated current is given as a reference to the boost converter. By separately considering the ac and dc dynamics of the boost converter, a novel controller is designed which achieves the input current reference tracking while also balancing the buffer capacitor. This control design is motivated by a Lyapunov stability analysis, which proves convergence of the relevant error signals. Simulation results are also provided to further validate the design.