A power conversion system with abnormal energy protection, the power conversion system comprising: a plurality of DC input power sources (Vdc1-Vdcn), a plurality of DC power converters, wherein an input side of each DC power converter is respectively coupled to one of the DC input power sources (Vdc1-Vdcn), and output sides of the DC power converters are coupled in parallel to each other to form a DC output bus, two output capacitors (41,42) coupled in series between a positive bus voltage end (Vb+) and a negative bus voltage end (Vb-) of the DC output bus, characterized in that it comprises additionally a protection circuit coupled between the positive voltage end of each one of the DC input power sources (Vdc1-Vdcn) and the negative voltage end of one of the DC input power sources (Vdc1-Vdcn), and a control unit configured to control the protection circuit, wherein the protection circuit comprises: a resistor (Ri) and a first semiconductor switch (Qa) coupled in series with the resistor (Ri) to form a series-connected auxiliary branch, either a second semiconductor switch (Qb) coupled in parallel to the series-connected auxiliary branch or a plurality of second semiconductor switches (Qb1-Qbn) each of them coupled between a respective one of the DC input power sources (Vdc1-Vdcn) and the output of the protection circuit, and a plurality of diodes (D1-Dn) each coupled to a respective one of the DC input power sources (Vdc1-Vdcn) and the input of the series-connected auxiliary branch, wherein when any one of the two output capacitors (41,42) is abnormal, the control unit is configured to turn on the first semiconductor switch (Qa) and after a delay time to turn on also the second semiconductor switch (Qb) or the plurality of second semiconductor switches (Qb1-Qbn) such that the protection circuit is configured to decouple the DC input power sources (Vdc1-Vdcn) from the two output capacitors (41,42) by shorting circuit paths between the DC input power sources (Vdc1-Vdcn) and the DC power converters. a plurality of DC input power sources (Vdc1-Vdcn), a plurality of DC power converters, wherein an input side of each DC power converter is respectively coupled to one of the DC input power sources (Vdc1-Vdcn), and output sides of the DC power converters are coupled in parallel to each other to form a DC output bus, two output capacitors (41,42) coupled in series between a positive bus voltage end (Vb+) and a negative bus voltage end (Vb-) of the DC output bus, characterized in that it comprises additionally a protection circuit coupled between the positive voltage end of each one of the DC input power sources (Vdc1-Vdcn) and the negative voltage end of one of the DC input power sources (Vdc1-Vdcn), and a control unit configured to control the protection circuit, wherein the protection circuit comprises: a resistor (Ri) and a first semiconductor switch (Qa) coupled in series with the resistor (Ri) to form a series-connected auxiliary branch, either a second semiconductor switch (Qb) coupled in parallel to the series-connected auxiliary branch or a plurality of second semiconductor switches (Qb1-Qbn) each of them coupled between a respective one of the DC input power sources (Vdc1-Vdcn) and the output of the protection circuit, and a plurality of diodes (D1-Dn) each coupled to a respective one of the DC input power sources (Vdc1-Vdcn) and the input of the series-connected auxiliary branch, wherein when any one of the two output capacitors (41,42) is abnormal, the control unit is configured to turn on the first semiconductor switch (Qa) and after a delay time to turn on also the second semiconductor switch (Qb) or the plurality of second semiconductor switches (Qb1-Qbn) such that the protection circuit is configured to decouple the DC input power sources (Vdc1-Vdcn) from the two output capacitors (41,42) by shorting circuit paths between the DC input power sources (Vdc1-Vdcn) and the DC power converters. a resistor (Ri) and a first semiconductor switch (Qa) coupled in series with the resistor (Ri) to form a series-connected auxiliary branch, either a second semiconductor switch (Qb) coupled in parallel to the series-connected auxiliary branch or a plurality of second semiconductor switches (Qb1-Qbn) each of them coupled between a respective one of the DC input power sources (Vdc1-Vdcn) and the output of the protection circuit, and a plurality of diodes (D1-Dn) each coupled to a respective one of the DC input power sources (Vdc1-Vdcn) and the input of the series-connected auxiliary branch, wherein when any one of the two output capacitors (41,42) is abnormal, the control unit is configured to turn on the first semiconductor switch (Qa) and after a delay time to turn on also the second semiconductor switch (Qb) or the plurality of second semiconductor switches (Qb1-Qbn) such that the protection circuit is configured to decouple the DC input power sources (Vdc1-Vdcn) from the two output capacitors (41,42) by shorting circuit paths between the DC input power sources (Vdc1-Vdcn) and the DC power converters.