A precharge system, comprising: a first input configured to be coupled to an AC power source ; a first circuit branch having a first contactor configured to be coupled between the first input and an AC to DC converter ; a second circuit branch having a variable frequency drive, VFD, , which is configured as an AC to AC converter comprising a converter , an internal DC bus circuit and an inverter , which is connected through an inductor and a second contactor to an AC input of the AC to DC converter , and being connectable through a disconnect switch and the second contactor respectively to both sides of the first contactor of the first circuit branch, with one side configured to be connected to the AC power source and another side configured to be connected to the AC to DC converter , wherein the inductor is connected between the VFD and the second contactor ; and a controller configured to: in a precharge operation mode, open the first contactor and close the second contactor and the disconnect switch to connect the VFD to said both sides of the first contactor of the first circuit branch for connecting the one side to the AC power source and for connecting the other side to the AC to DC converter , and to prevent direct current flow from the first input to the AC to DC converter and allow current flow from the AC output of the VFD through the inductor ; and in a normal operation mode, close the first contactor and open the second contactor and the disconnect switch to connect the AC power source to the AC to DC converter , and to allow direct current flow from the first input to the AC to DC converter and prevent current flow from the AC output of the VFD through the inductor . a first input configured to be coupled to an AC power source ; a first circuit branch having a first contactor configured to be coupled between the first input and an AC to DC converter ; a second circuit branch having a variable frequency drive, VFD, , which is configured as an AC to AC converter comprising a converter , an internal DC bus circuit and an inverter , which is connected through an inductor and a second contactor to an AC input of the AC to DC converter , and being connectable through a disconnect switch and the second contactor respectively to both sides of the first contactor of the first circuit branch, with one side configured to be connected to the AC power source and another side configured to be connected to the AC to DC converter , wherein the inductor is connected between the VFD and the second contactor ; and a controller configured to: in a precharge operation mode, open the first contactor and close the second contactor and the disconnect switch to connect the VFD to said both sides of the first contactor of the first circuit branch for connecting the one side to the AC power source and for connecting the other side to the AC to DC converter , and to prevent direct current flow from the first input to the AC to DC converter and allow current flow from the AC output of the VFD through the inductor ; and in a normal operation mode, close the first contactor and open the second contactor and the disconnect switch to connect the AC power source to the AC to DC converter , and to allow direct current flow from the first input to the AC to DC converter and prevent current flow from the AC output of the VFD through the inductor . <EOS>