Control law for transformerless converters connected to the grid through an L filter

This paper presents a control law for single-phase power converters, coupled to the grid by means of an L filter, aimed at active power injection. This control law makes use of an estimation scheme which obtains estimations of the filter parameters in order to cope with the compensation of time-periodic signals arising in the error average model and with the possible existence of harmonics in the grid voltage. An evaluation of the proposed control law is performed by means of numerical simulations where a single-phase H-bridge inverter with unipolar pulse width modulation is used.