This invention discloses a power electronic converter that has a common reference point for the measurement of voltages and currents, making it possible to use non-isolated or isolated voltage and current sensors. The disclosed converter has an N-type power electronic conversion leg that consists of two sets of power electronic devices with their both ends connected to a capacitor to form a DC bus and their mid-point connected to the common reference point through an inductor and a current sensor. The disclosed converter has one or more power electronic conversion leg that consists of two sets of power electronic devices with the positive end connected to the positive rail of the DC bus and the negative end connected either to the common reference point N, in which case the power electronic conversion leg is denoted the A-type, or to the negative rail of the DC bus, in which case the power electronic conversion leg is denoted the B-type. For each present A-type or B-type power electronic conversion leg, its mid-point is connected to one terminal of the corresponding input/output port, together with a current sensor connected between the common reference point and the other terminal of the corresponding input/output port. The disclosed converter also has a capacitor connected to the positive rail of the DC bus and the common reference point through a current sensor. A storage system and/or a load can be connected in parallel with or in place of this capacitor. The disclosed converter can be used for DC/DC, AC/DC, DC/AC, and AC/AC conversion.