The utility model provides a novel bidirectional bipolar direct-current converter. Two power electronic devices are connected in series between the positive end of the input end of the converter and the negative end of the output end of the converter. Two power electronic devices are connected in series between the negative end of the input end of the converter and the positive end of the output end of the converter. The positive end of the input end and the negative end of the input end are respectively connected with a public ground end through input capacitors. The negative end of the output end and the positive end of the output end are connected with a public ground end through output capacitors. The connecting ends of each two power electronic devices are connected with the public ground ends through inductors. A digital control panel piece enables collected values of voltage and current to be compared with the preset values of voltage and current. A PI controller controls a PWM generator to output a drive signal according to the comparison results, so as to control the on/off of the power electronic devices. Compared with the prior art, the converter provided by the utility model can change the voltage level, can adjust the flow direction of a power grid, and can protect a broken-down power grid.