An electric vehicle controller includes an inverter that drives a motor by receiving power supplied from an overhead line, a brake chopper circuit that includes a switching device and a braking resistor and is connected in parallel with the inverter, a voltage detector that detects a bus voltage applied to DC buses, and a control unit that performs power consumption control of causing the braking resistor to consume regenerative power supplied from the motor and overvoltage suppression control of suppressing the bus voltage from being excessive. The control unit controls the switching device such that a second duty ratio used at the time of performing the overvoltage suppression control is lower than a first duty ratio used at the time of performing the power consumption control.

The present invention relates to a braking system for a vehicle at least partially propelled by an electric traction motor, the braking system comprising an electric machine electrically connected to an electric source; an air flow producing unit mechanically connected to, and operated by, the electric machine; and an electrical brake resistor arrangement positioned in fluid communication between the air flow producing unit and an ambient environment, the electrical brake resistor arrangement being electrically connected to the electric source and arranged to heat air supplied from the air flow producing unit by electrical power received from the electric source, and to supply heated air to the ambient environment.

The present invention relates to a braking system for a vehicle at least partially propelled by an electric traction motor, the braking system comprising an electric machine electrically connected to an electric source; an air flow producing unit mechanically connected to, and operated by, the electric machine; and an electrical brake resistor arrangement positioned in fluid communication between the air flow producing unit and an ambient environment, the electrical brake resistor arrangement being electrically connected to the electric source and arranged to heat air supplied from the air flow producing unit by electrical power received from the electric source, and to supply heated air to the ambient environment.

A braking grid cooling system may include a fan having a hub supporting a rotor and at least partially enclosing a stator, and a plurality of fan blades connected to and projecting radially from the hub; and a dynamic braking grid receiving the fan in a nested relation such that a combined height of the grid and the fan is less than a sum of a height of the grid and a height of the fan.

A braking grid cooling system may include a fan having a hub supporting a rotor and at least partially enclosing a stator, and a plurality of fan blades connected to and projecting radially from the hub; and a dynamic braking grid receiving the fan in a nested relation such that a combined height of the grid and the fan is less than a sum of a height of the grid and a height of the fan.

Methods and systems detect short circuits in an electrical system, such as a dynamic braking grid of a vehicle. The methods and system measure a characteristic of a current that is conducted through one or more resistive elements of an electrical system. The current is supplied to the electrical system from a power source as an applied voltage. A resistance change signal representative of a change in one or more electrical resistances of the one or more resistive elements is determined The resistance change signal can be based at least in part on a difference between the characteristic of the current that is measured and a low pass filtered value of one or more of the characteristic of the current that is measured or the applied voltage supplied by the power source. A short circuit event is identified based at least in part on the resistance change signal.

The first power converter is connected with a circuit connected with an overhead line, and an intermediate link, and mutually converts power. The second power converter is connected with the intermediate link, and a circuit electrically connected with an induction motor, and mutually converts power. The auxiliary power-supply device receives power from the intermediate link, and supplies power to a load. The operation controller controls the operation/deactivation of the first power converter based on acceleration and speed of a vehicle, auxiliary source power, and a restriction value for regenerative power to the overhead line in such a way that the power to be supplied to the auxiliary power-supply device becomes equal to or larger than the auxiliary source power, and the regenerative power flowing to the overhead line 105 becomes equal to or smaller than the restriction value.

The first power converter is connected with a circuit connected with an overhead line, and an intermediate link, and mutually converts power. The second power converter is connected with the intermediate link, and a circuit electrically connected with an induction motor, and mutually converts power. The auxiliary power-supply device receives power from the intermediate link, and supplies power to a load. The operation controller controls the operation/deactivation of the first power converter based on acceleration and speed of a vehicle, auxiliary source power, and a restriction value for regenerative power to the overhead line in such a way that the power to be supplied to the auxiliary power-supply device becomes equal to or larger than the auxiliary source power, and the regenerative power flowing to the overhead line 105 becomes equal to or smaller than the restriction value.

A resistive grid includes a frame and at least one resistive element. The frame has a first frame end and a second frame end opposite the first frame end. The first frame end and the second frame end are joined by frame sides. The first frame end has a first length that is shorter than a second length of the second frame end. The at least one resistive element extends between the first frame end and the second frame end. The at least one resistive element has a first portion proximate the first frame end, and a second portion proximate the second frame end. The first portion is configured to have one or both of decreased heat generation or decreased electrical resistance relative to the second portion.

A resistive grid includes a frame and at least one resistive element. The frame has a first frame end and a second frame end opposite the first frame end. The first frame end and the second frame end are joined by frame sides. The first frame end has a first length that is shorter than a second length of the second frame end. The at least one resistive element extends between the first frame end and the second frame end. The at least one resistive element has a first portion proximate the first frame end, and a second portion proximate the second frame end. The first portion is configured to have one or both of decreased heat generation or decreased electrical resistance relative to the second portion.