Drive system

A system comprising:

• a positive bus configured to be connected with a source of electric current;
• a negative bus configured to be connected with the source of the electric current, the positive bus and the negative bus connected with a converter that converts the electric current for a motor of a powered system;
• a braking resistor coupled with the positive bus;
• several parallel circuit legs coupled in series with the braking resistor, each of the circuit legs including a contactor;
• and
• several semiconductor switches connected in parallel to each other with each of the semiconductor switches connected in series with a different circuit leg of the several parallel circuit legs between the positive bus and the negative bus,
• wherein, during a regenerative braking mode or a rheostatic braking mode of the powered system, regenerated electric current from the motor is conducted to the braking resistor and dissipated as heat with different ones of the semiconductor switches closing at different times while others of the semiconductor switches remain open.

A system comprising:

• one or more first semiconductor switches;
• one or more second semiconductor switches;
• two or more inductors, with each inductor of the two or more inductors configured to be disposed onboard a powered system and selectively coupled with a source of first electric current and a converter that converts the first electric current for a motor of the powered system, the two or more inductors each coupled with nodes located between the one or more first semiconductor switches and (a) one or more diodes or (b) the one or more second semiconductor switches, second semiconductor switches coupled with a converter;
• contactors connected in parallel with each other between the source of the first electric current and the converter;
• and
• braking resistors connected in parallel with each other, each of the braking resistors connected in series with a different contactor of the contactors between the contactor and the converter;
• wherein, the first semiconductor switch of the one or more first semiconductor switches is coupled with a contactor of the contactors connected in parallel with each other, such that the contactor of the contactors connected in parallel with each other is between the first semiconductor switch of the one or more first semiconductor switches and the braking resistors,
• wherein, during a regenerative or rheostatic braking mode of operation of the powered system, regenerated electric current from the motor of the powered system is conducted to the braking resistors and dissipated as heat, based on which of the contactors or the one or more first semiconductor switches are closed.