Electric power conversion circuit and electric power transmission system

An electric power conversion circuit includes: first through fourth port terminals; a first diode having an anode connected to the first port terminal; a second diode having a cathode connected to the second port terminal; a third diode having a cathode connected to the first port terminal; a fourth diode having an anode connected to the second port terminal; first through fourth switches that are bridge-connected between a cathode of the first diode and an anode of the second diode; fifth through eighth switches that are bridge-connected between an anode of the third diode and a cathode of the fourth diode; a first bootstrap circuit that is connected to control terminals of the first through fourth switches; and a second bootstrap circuit that is connected to control terminals of the fifth through eighth switches.