An ECU performs a controlling process including: switching a main converter to a boost converter CNV2 when a boost converter CNV1 is set as a main converter and when a first stress value Va is greater than a second stress value Vb; switching a sub converter to the boost converter CNV1; switching the main converter to the boost converter CNV1 when the boost converter CNV1 is not set as a main converter, and when the second stress value Vb is greater than the first stress value Va; and switching the sub converter to the boost converter CNV2.

In a diagnostic device, a determiner determines whether a rotational speed of an AC motor is within a low rotational-speed range in which its rotational speed is approximately zero. An input-voltage estimate calculator calculates, as an input-voltage estimate, an estimate of an input voltage to an inverter when it is determined that the rotational speed of the AC motor is within the low rotational-speed range. A malfunction determiner performs a diagnostic task. The diagnostic task calculates an absolute value of a difference between an input-voltage measurement value measured by an input voltage sensor and the input-voltage estimate. The diagnostic task determines whether the absolute value of the difference is higher than a predetermined voltage threshold. The diagnostic task determines that there is a malfunction in the input voltage sensor upon determining that the absolute value of the difference is higher than the predetermined voltage threshold.

A pantograph device of a trolley-type truck includes: a base frame; a bottom frame rockably attached to the base frame; a top frame rockably attached to the vicinity of the top end portion of the bottom frame through a connecting shaft; a collector shoe rockably supported in proximity to the top end portion of the top frame; a hydraulic cylinder for raising and lowering the bottom frame, attached to the base frame; and a spring which acts so as to rotate the top frame upward through the connecting shaft. By erecting the bottom frame by the hydraulic cylinder, the tensile force produced in the spring is increased and the top frame is rotated upward through the connecting shaft. This makes it possible to obtain a wide movable range without use of a long and strong spring and enhance the followability to overhead wires without increasing pressing force.

Inverterless running control is control in which an inverter is set to a gate cut-off state, an engine is driven to mechanically rotate a motor-generator and to generate in the motor-generator, counter-electromotive torque in accordance with a difference between a counter-electromotive voltage of the motor-generator and a system voltage, and a vehicle runs with drive torque applied to an output shaft as reaction force of the counter-electromotive torque. An ECU controls drive torque to produce driving force determined by an accelerator position by raising or lowering the system voltage during inverterless running control.

The invention relates to supplying electric traction motors of a rail vehicle with electrical energy. Internal combustion engine/machine combination are operated such that alternating current is generated and used for operating at least one electric traction motor, in a first operating state of the machine in a generator mode. In a second operating state of the machine, an associated machine converter supplies alternating current and drives the associated internal combustion engine, wherein at least the machine converter associated with the second electrical machine is supplied, while the associated electrical machine is in the second operating state, via an electrical DC voltage line with direct current by a rectifier associated with the first machine, wherein the rectifier produces the direct current from alternating current generated by the first electrical machine.

An electrical system architecture for a mobile, electric hybrid machine includes a first bus configured to receive electric power at a first, selectively adjustable voltage from an electrical power source. A second bus is configured to receive electric power at a second voltage that is lower than the first voltage. A controller is configured to determine a desired magnitude of the second voltage for the second bus, produce a signal indicative of a magnitude of the first, selectively adjustable voltage that is a multiple of the desired magnitude of the second voltage, and adjust the magnitude of the first voltage in the first bus to the multiple of the desired magnitude of the second voltage. A fixed-ratio power converter is configured to convert the power at the first voltage in the first bus to the power at the second voltage in the second bus.

A generator motor unit includes a generator motor including a rotor equipped with magnets, and magnetic bodies that protrude from a wall surface, a first stator that makes magnetic flux act on the magnets, thereby generating torque in the rotor, and a second stator that makes magnetic flux act on the magnetic bodies, thereby generating torque in the rotor; and a controller that controls energization of coils of the first stator and the second stator.

A control device for a power supply system includes a pre-charge unit, the power supply system having a main electric storage device, a smooth capacitor, a step-up circuit, an open-close switch, a voltage source and a regulation element. The regulation element regulates a current flowing from the smooth capacitor toward the open-close switch. The voltage source is connected to a connection portion between the open-close switch and the step-up circuit, and outputs an output voltage higher than a voltage of the main electric storage device before the open-close switch is shifted from a disconnection state to a connection state. The pre-charge unit executes a pre-charge of the smooth capacitor by supplying electric power from the voltage source to the smooth capacitor before the open-close switch is shifted from the disconnection state to the connection state.

An electrical source system has an electrical power converter which has a plurality of switching elements and performs an electrical power conversion with first and second electricity storage apparatus; and a control apparatus which controls an operation of the electrical power converter, when the electrical power converter performs the electrical power conversion with one electricity storage apparatus, the control apparatus controls the electrical power converter to change a switching state of one of two switching elements while keeping a switching state of the other one of the two switching elements in an ON state, each of two switching elements constitutes predetermined arm element whose switching state should be changed to perform the electrical power conversion with the one electricity storage apparatus.

An electrical power supply system for a machine is provided. The electrical power supply system includes a generator, a primary power converter unit and an auxiliary power converter unit. The primary power converter unit is electrically coupled to the generator. The primary power converter unit includes a rectifier connected to the generator and an inverter electrically connected to the rectifier by a Direct current (DC) link. Further, the auxiliary power converter unit is electrically connected to the DC bus within the primary power converter unit.