System and method for testing power transistors

#This application relates to a system and method for testing electrical devices, and more particularly, to a system and method for testing power transistors.

#Power converters/inverters are commonly used in a machine for motor control. Power converters/inverters usually include a plurality of power transistors, and these power transistors may be switched on and off to modulate an output voltage from the power converter/inverter. Examples of power transistors may include bipolar junction transistors (BJT), the Darlington device, metal oxide semiconductor field effect transistors (MOSFET), and insulated gate bipolar transistors (IGBT). In particular, IGBTs have been widely used in a wide range of applications due to its high switching speed and ability of conducting very high current.

#High voltage power converters/inverters are usually expensive, and failure of power transistor components could be costly. Additionally, in the event that there is a malfunction in the power transistors or their wiring, damage may be caused to the other power components in the circuit. Therefore, it becomes highly desirable that any faults with power transistors, their driving circuit, and associated wiring are detected before high voltage is applied to the power converters/inverters. Furthermore, it may also be important to precisely and quickly locate the type of fault (e.g., a power transistor fault, an open circuit fault), and if possible, positions of the fault, and to disable the inverter/converter functionality once a fault is detected.

#FIG. 1 provides a block diagram of a machine in accordance with an exemplary embodiment of the present disclosure;

#FIG. 2 provides a diagrammatic illustration of a power transistor testing system, in accordance with an exemplary embodiment of the present disclosure;

#FIG. 3 provides a flowchart of an exemplary power converter test process, in accordance with an embodiment of the present disclosure;

#FIG. 1 provides a block diagram of a machine in accordance with an exemplary embodiment of the present disclosure. Machine 10 may include, among other things, a power source 110, a power electronics system 120, a traction system 130, a control system 140, and a power transistor testing system 150. Machine 10, as the term is used herein, refers to a fixed or mobile machine that may perform some-type of operation associated with a particular industry, such as mining, construction, farming, etc., and that operates between or within work environments. Examples of machines include trucks, cranes, earth moving vehicles, mining vehicles, backhoes, material handling equipment, fanning equipment, marine vessels, and on-highway vehicles.

#Power source 110 may include various components configured to provide electric power for use by one or more systems of machine 10. Power source 110 may include a prime mover 101 and a generator 102 driven by prime mover 101. Prime mover 101 may be a combustion engine, such as, for example, a diesel engine. Generator 102 may be an AC generator, otherwise known as an alternator, which generates alternating voltage by rotating a coil in the magnetic field or by rotating a magnetic field within a stationary coil. Alternatively, power source 110 may include any other suitable device for providing an electrical power output such as, for example, a battery, a fuel cell, switched reluctance machine, or any other type of power source configured to provide electrical power to machine 10.

#Power electronics system 120 may be electrically coupled to power source 110 via a first set of conductors, and to traction system 130 via a second set of conductors. Traction system 130 may include at least one load, such as an electric motor. Power electronics system 120 may be configured to convert power provided by power source 110 into power forms appropriate for consumption by traction system 130. Power electronics system 120, for example, may include a power rectifier to convert AC voltage supplied by power source 110 to a DC voltage output, and may further include a power inverter to convert the DC voltage to an AC voltage of a certain waveform. Power electronics system 120 may provide voltage and/or current outputs to drive traction system 130 and/or control system 140.