Electric vehicle drive system

摘要

An electric vehicle drive system includes an electric-vehicle power conversion device, and an earth ground switch that is a triple-pole single-throw switch having a switching contact unit. The electric-vehicle power conversion device includes a smoothing circuit unit that includes a filter capacitor that receives and stores therein power supplied from an overhead wire, an inverter that converts a DC voltage of the smoothing circuit unit into an AC voltage to drive an electric motor, and a brake chopper circuit that consumes excess power, which cannot be returned toward the overhead wire. A brake resistance in the brake chopper circuit is connected to the switching contact unit. When the switching contact unit is closed, the brake resistance is electrically connected between the positive electrode and the negative electrode of the filter capacitor.

主权项

1. An electric vehicle drive system comprising:
an electric-vehicle power conversion device that converts DC power or AC power supplied from an overhead wire into desired AC power to drive an electric motor as a load; a first breaker that blocks an electric current flowing between the overhead wire and the electric-vehicle power conversion device; and a grounding switch that grounds the first breaker, wherein the electric-vehicle power conversion device includes a main circuit unit and a second breaker, where the main circuit unit includes at least a smoothing circuit unit that contains a filter capacitor that receives and stores therein power supplied from the overhead wire, and an inverter that converts a DC voltage from the smoothing circuit unit into an AC voltage to drive the electric motor as a load, and where the second breaker blocks a power supply path between the first breaker and the inverter, wherein the grounding switch is configured as a single-throw switch that includes three or more pole switching contacts, and wherein a predetermined resistor that is one of circuit elements that constitute the main circuit unit is connected to a switching contact of the grounding switch such that when the switching contact of the grounding switch is closed, the predetermined resistor is electrically connected between a positive electrode and a negative electrode of the filter capacitor.