Desenvolvimento de uma carga eletrônica c.c. regenerativa para ensaio de bancos de baterias

Abstract

Tests of electronic converters, voltage sources and batteries are commonly accomplished in resistive commuted loads or in no-regenerative electronic loads and all the energy of the tests is wasted. Although there are several solutions of electronic loads available, that they allow several operation modes and dynamic tests, but few of them are regenerative. This work proposes a d.c. regenerative electronic load that makes possible the control of the discharge test process in batteries and regenerates the energy to the a.c. grid. The electronic load can also be applied in tests of the d.c. voltage sources. The proposed load has two converters, making possible reduction of losses in relation to the three converters loads, and works in constant current operation mode, controlling the current drained from the tested device. The d.c. regenerative electronic load prototype proposed has a power of 635W. The electronic load has at the input stage a current fed Push-Pull converter which elevates the voltage and adds electric isolation. A full bridge monophase inverter at the output stage provides a sinusoidal current waveform with high power factor to the a.c. grid. Experiments showed good dynamic answer in the current control provided to a.c. grid and also was possible provide a sinusoidal current waveform even under harmonic polluted voltage sources, due to the employment of a PLL. In the experimental results on the output stage, losses of about 5% of the drained power were obtained. By including the input stage, the losses will increase about 10%. This regenerative load presents two main advantages to the industrial sector. First, it allows energy saving and second the possibility of controlled and dynamic tests.