Precharging using a motor-inverter system

A method of controlling an electrical system, comprising:

• receiving a request to initiate a transition to a desired operating mode, the desired operating mode being one of a propulsion mode and a charging mode, the electrical system including an inverter and a multi-phase electric motor configured to be powered by a battery via a propulsion bus, a charge port configured to be electrically connected to the inverter and the multi-phase electric motor, and a charging system including a charge port bus configured to electrically connect the charge port to a phase of the electric motor and to a direct current (DC)-DC converter, wherein part of the inverter and the electric motor form a power factor correction (PFC) stage and the DC-DC converter forms part of a DC-DC conversion stage, and the charging system includes a precharge circuit electrically connected to the charge port bus, the charge port bus including a positive bus configured to connect the charge port to the phase of the electric motor, the precharge circuit including a first switch across the positive charge port bus and a resistor connected to the positive charge port bus in parallel with the first switch;
• disconnecting the battery from the propulsion bus;
• precharging at least the propulsion bus by electrically connecting the precharge circuit to the charge port bus;
• and
• controlling the electrical system according to the desired operating mode.

A vehicle system comprising:

• a battery, an inverter and a multi-phase electric motor connected in parallel to a propulsion bus;
• a charge port configured to be electrically connected to the inverter and the electric motor;
• a charging system including a charge port bus configured to electrically connect a charge port to a phase of the electric motor and to a direct current (DC)-DC converter, wherein a phase of the inverter and the electric motor forms a power factor correction (PFC) stage and the DC-DC converter forms part of a DC-DC conversion stage, and the charging system includes a precharge circuit connected to the charge port bus, the charge port bus including a positive bus configured to connect the charge port to the phase of the electric motor, the precharge circuit including a first switch across the positive charge port bus and a resistor connected to the positive charge port bus in parallel with the first switch;
• and
• a controller configured to control the precharge circuit to precharge one or more components of the charging system.