Method and device for measuring the state of health of semiconductor-based electronic components

1 . A method for measuring the state of health, at several times ti, of at least one semiconductor-based power electronics component by computing a quantitative indicator D(ti) of the degradation of the power electronics component, in order to determine the progression of the aging of said power electronics component, the power electronics component having at least one input terminal and one output terminal for an electric current of intensity I, between which a voltage V is established,

the power electronics component having a zero temperature coefficient point ZCP defined by an electric current I,ZCP and a voltage V,ZCP, ZCP being independent of the temperature,

the method using an electric current sensor, a voltage sensor and a processor exchanging information with said sensors,

the method comprising:

a—a first step of determining, at an initial time t0, a first current value I(t0)=I,ZCP0 when the voltage V is equal to a voltage V(t0)=V,ZCP0, the power electronics component then being in an “initial time” state;

b—a step of measuring a value of the current I at each subsequent time ti, when the voltage V at the time ti of the power electronics component is equal to the voltage V,ZCP0, the power electronics component then being in a “time ti” state;

c—a step of the processor computing a quantitative indicator D(ti) of the aging of the power electronics component at each subsequent time ti, the value of which indicator depends on the variation in the value of the current I between the “initial time” state and the “time ti” state, the aging being independent of the voltage V,ZCP but dependent on the current I,ZCP, which decreases with aging.

2 . The measuring method according to claim 1 , comprising a measurement of the current I,ZCP(ti) when the steady-state voltage is at the value V,ZCP0, wherein the intensity of the electric current I(ti) in the time t state corresponds to the current I,ZCP(ti) at the zero temperature coefficient point of the electronic component, the measurement being made without the need for any additional measurement, especially by means of a temperature sensor.

3 . The measuring method according to claim 1 , wherein no temperature sensor is implemented and no temperature estimation is required for steps a, b and c, the quantitative indicator D(ti) of the degradation of the electronic component being independent of the temperature.

4 . The measuring method according to claim 1 , wherein the measuring method comprises, prior to step a:

i—a step comprising at least two series of measurements of the electric current I by the electric current sensor and of the voltage V by the voltage sensor, the series of measurements (I,V) being taken at different temperatures;

ii—a step of the processor computing a voltage value V,ZCP0 and an electric current value I,ZCP0 at the zero temperature coefficient point ZCP, from the measurements of step i, the zero temperature coefficient point ZCP being the point of intersection of the two series of measurements (I,V) of step i, the current I(t0) and voltage V(t0) at the “initial time” state being equal to I,ZCP0 and V,ZCP0, respectively.

5 . The measuring method according to claim 1 , wherein the at least one semiconductor-based power electronics component is embedded or installed in an operational electrical system, the method for measuring the state of health of the component being carried out while the electrical system is in operation.

6 . The measuring method according to claim 1 , wherein the measurement of the voltage V(ti) is carried out in step b with a relative accuracy that depends on the type of power electronics component, this relative accuracy having a value of less than 5%.

7 . The measuring method according to claim 1 , wherein the degradation concerns the degradation of the electrical interconnections of the components.

8 . The measuring method according to claim 1 , wherein the state of health corresponding to the time t in step c) is obtained without carrying out a series of measurements which would aim to trace a cluster of characteristics at different temperatures so as to deduce the position of the ZCP point, wherein the point of intersection of the cluster of characteristics corresponding to a given state of health is the ZCP point corresponding to said state of health, the voltage V,ZCP being determined a first time to obtain the voltage V,ZCP0 so as to implement step a) of said method.

9 . The measuring method according to claim 1 , wherein the indicator D(ti) of the state of health of the electronic component at the time ti is determined by comparing the current at the time i I,ZCP(ti) with the current at the initial time I,ZCP(t0).

10 . The measuring method according to claim 1 , wherein the quantitative indicator D(ti) of the state of health of the component at the time ti is determined by computing the ratio of the difference of the current at the time i I,ZCP(ti) and the current at the initial time I,ZCP(t0)) and of the difference between the current at a final time I,ZCP(tfinal) and the current at the initial time I,ZCP(t0)) wherein the current at the final time I,ZCP(tfinal) is the value reached when the level of degradation of the component requires its replacement and wherein the current at the initial time I,ZCP(t0) corresponds to the intensity of the component in the healthy state.

11 . A device for measuring the state of health, at one or more times ti, of at least one semiconductor-based power electronics component by computing a quantitative indicator D(ti) of the degradation of the power electronics component, in order to determine the progression of the aging of said power electronics component,

the device having at least one input terminal and one output terminal for the electric current of intensity I, between which a voltage V is established, the power electronics component having a zero temperature coefficient point ZCP defined by an electric current I,ZCP and a voltage V,ZCP,ZCP being independent of the temperature,

the device comprising an electric current sensor, a voltage sensor and a processor exchanging information with said sensors, configured to implement the following steps:

a—a first step of determining, at an initial time t0, a first current I(t0)=I,ZCP0, when the voltage V is equal to a voltage V(t0)=V,ZCP0, the power electronics component being in an “initial time” state;

b—a step of measuring a value of the current I at each subsequent time ti, when the voltage V at the time ti is equal to the voltage V,ZCP0, the power electronics component being in a “time ti” state;

c—a step of the processor computing a quantitative indicator D(ti) of the aging of the power electronics component at each subsequent time ti, the value of which indicator depends on the variation in the value of the current I between the “initial time” state and the “time ti” state, the aging being independent of the voltage V,ZCP but dependent on the current I,ZCP, which decreases with aging.

12 . The device according to claim 11 , characterized in that the at least one semiconductor-based power electronics component is bipolar or mixed.

13 . A power electronics module integrating a device according to claim 11 for at least two electronic components in parallel and/or in series.

14 . A system embedding one or more power electronics modules according to claim 13 , the device for measuring the state of health of at least one power electronics component integrated into each module providing a quantitative indicator of degradation.

15 . A system embedding one or more power electronics modules according to claim 14 , the system being a system for managing electrical energy and/or converting electrical energy for renewable energies or a transport system with electric traction or a stationary system.