A diagnostic system for a power conversion apparatus including a semiconductor device and performing a switching operation for carrying and interrupting a main current to a main current is disclosed. This system includes a trigger circuit that acquires reference time for the switching operation; and a delay time calculation circuit that acquires first time at which the main current takes a first main current set value and second time at which the main current takes a second main current set value, and that detects numerical data about a difference between the first time and the reference time and numerical data about a difference between the second time and the reference time.

A method for determining failure of a power element for use in an electronic device is provided. The electronic device includes a power element and a detection circuit. The method includes the steps of: obtaining a temperature-calculation model of the power element, and obtaining a parameterized temperature-calculation model of a power-element parameter and a parameterized temperature of the power element; detecting load information and the power-element parameter by the detection circuit; calculating a modeled temperature of the power element according to the load information and the temperature-calculation model, and calculating the parameterized temperature of the power element according to the power-element parameter and the parameterized temperature-calculation model; determining whether an error between the modeled temperature and the parameterized temperature exceeds a permitted range; and determining that the power element has failed in response to the error exceeding the permitted range.

A state determination device includes an initial waveform storage unit, a waveform acquisition unit, an element temperature acquisition unit, a past waveform storage unit, and a failure state determination unit. The failure state determination unit classifies the time waveform based on the initial time waveform of the gate voltage, the current time waveform of the gate voltage, the element temperature, and the past time waveform of the gate voltage, and determines a fault condition of the IGBT.

A measurement circuit device for a vehicle includes a power transistor and a voltage measurement circuit coupled to the power transistor that measures a voltage across the power transistor. The measurement circuit device also includes a microcontroller that determines a junction temperature using the measured voltage and adjusts a capacity of the power transistor based on the determined junction temperature. In some embodiments, the measurement circuit device may include a clamping device that clamps the voltage across the transistor when the transistor is off. The measurement circuit device may also include an analog-to-digital converter that converts the measured voltage from an analog value to a digital value.

Systems, devices and methods are provided herein for measuring a junction temperature of a transistor. A system includes a power inverter configured to supply power to a load, the power inverter including the transistor that is configured to switch between an on-state and an off-state and generate a load current during the on-state; a current sensor configured to measure the load current; a voltage transit slope detection circuit configured to determine a voltage transit slope corresponding to a voltage across the transistor during a turn-off period of the transistor during which the transistor is in the off-state; and a processing unit configured to determine the junction temperature of the transistor based on the measured load current and the determined voltage transit slope.

A testing device for inspecting an electronic device by causing contact terminals to electrically contact the electronic device, includes: a mounting table formed with a light transmission member opposite the side on which a inspection object is placed and having therein a coolant flow path through which a coolant capable of transmitting light flows; a light irradiation mechanism disposed so as to face the surface opposite the inspection object placement side of the mounting table, and having LEDs pointing toward the inspection object; and a controller controlling absorption of heat by the coolant and heating by the lights from the LEDs to control the temperature of the electronic device to be inspected. The controller controls the light output from the LEDs based on the measured temperature of the electronic device to be inspected and controls the absorption of heat by the coolant based on the LED light output.

A method for manufacturing a semiconductor device having a trench gate structure is provided. In the method, a first voltage-current characteristic indicating a relation between the main current and the gate voltage under a first temperature is measured to calculate a first threshold voltage. A second voltage-current characteristic indicating a relation between the main current and the gate voltage under a second temperature different from the first temperature is measured to calculate a second threshold voltage. It is determined whether the semiconductor device is a non-defective product or a defective product based on whether a difference between the second threshold voltage and the first threshold voltage is larger than a determination threshold value.

A power supply circuit for measuring transient thermal resistances includes an inverter circuit provided on a primary side of a transformer and controlled by a PWM signal, a rectifier circuit provided on a secondary side of the transformer and including a DC reactor, and a control circuit controlling the PWM signal so as to output a pulsed output current from the rectifier circuit to a semiconductor device to be measured. The control circuit sets a first PWM frequency at rising timing of the output current, and sets a second PWM frequency when a predetermined time t1 elapses from the rising timing of the output current. The control circuit sets the first PWM frequency higher than the second PWM frequency.

The present invention concerns a method and a device for estimating a level of damage or a lifetime expectation of a power semiconductor module comprising at least one die that is mechanically, thermally, and electrically attached to a substrate, composed of plural layers of different materials. The invention: obtains power losses of the power semiconductor module, obtains the temperature in at least two different locations of the power semiconductor module, estimates a thermal model between the at least two different locations of the power semiconductor module using the determined power losses and the obtained temperatures, determines if a notification indicating the level of damage or the lifetime expectation has to be performed according to the estimated thermal model and a reference thermal model. notifies the level and location of damage or the lifetime expectation if the determining step determines that the notification has to be performed.

A system and method for measuring a junction temperature of a power module junction temperature are provided. The method is capable of improving accuracy of temperature measurement by more accurately applying temperature change in a junction temperature rising section, capable of more accurately predicting durability life of a power module, and capable of increasing output power of the power module.