Monitoring and fault diagnosis of single-and multi-converter power systems

Abstract

As described herein is a vehicle, system, method and device for monitoring, detecting and diagnosis of one or more faults in single- or multi-converter power system. Through use of existing devices within the power system, particularly semiconductor devices, output parameters may be monitored for deviations from normal operation. In addition, faults may be detected and/or diagnosed within the failure withstand time of the existing device.

Description

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

For more complete understanding of the features and advantages of the present invention, reference is now made to a description of the invention along with accompanying figures, wherein:

FIGS. 1A-1D depict simplified representative schematics of power systems in accordance with various embodiments described herein;

FIG. 2 depicts a representative schematic of a circuit layout of a cascaded converter with one or more devices;

FIG. 3A-3H depict representative schematics of operational states of a cascaded multiconverter system;

FIG. 4A-4F depict representative topological states on 14V and 42V bus short circuit faults;

FIG. 5 depicts a representative diode open circuit fault in a load converter;

FIG. 6 depicts a representative example of a 14V DC bus short circuit fault;

FIG. 7 depicts a representative example of a cross-variance matrix of third order statistical moments of particular system parameters;

FIG. 8 depicts a representative example of simulated IGBT2 short circuit in load converter when operating under steady state;

FIG. 9 depicts representative examples of a measured IGBT2 short circuit in a load converter when operating under steady state viewing (A) a 14V bus voltage waveform and (B) a zoomed projection of the fault point;

FIG. 10 depicts a representative example of a third moment of a simulated load O/P voltage (flv signal) detecting a switch (IGBT2) short circuit fault in a load converter in about 400 microseconds;

FIG. 11 depicts a representative example of a third moment of measured load O/P voltage (flv signal) detecting a switch (IGBT2) short circuit fault in a load converter in about 400 microseconds;

FIG. 12 depict representative examples of a measured 14V DC bus short circuit fault when operating under steady state viewing (A) a 14V bus voltage waveform and (B) a zoomed projection of a fault point;

FIG. 13 depicts a representative example of a measured 14V DC bus short circuit fault under steady state operation viewing a 14V bus current waveform;

FIG. 14 depicts a representative example of a third moment of a measured load O/P voltage (flv signal) detecting a possible 14V DC bus short circuit fault in about 10 microseconds;

FIG. 15 depicts a representative example of a third moment of a measured load O/P current (flc signal) detecting a 14V DC bus short circuit fault in about 1.5 milliseconds;

FIG. 16 depicts a representative example of a DC distribution system;

FIG. 17A-D depict representative examples of transients under a loss of a port bus 3-phase power supply, wherein voltage is in volts and t is in seconds;

FIG. 18 depicts a representative example of a port bus voltage (VDCPS1);

FIG. 19 depicts a representative example of a port bus current (IDCPS1);

FIG. 20 depicts a representative example of a third moment of VDCPS1; and

FIG. 21 depicts a representative example of a third moment of IDCPS1.

Claims

1. A method for detecting a fault in a power converter system comprising: monitoring continuously an output parameter at the power converter; andobtaining at least one statistical moment of a sampled window of the continuously monitored parameter, wherein the at least one statistical moment is provided by a mean of a moving sampled window measure as compared with a current measure from a defined sample window size.

2. The method of claim 1, wherein the method uses a cross-variance matrix expression for an nth order moment, wherein n is 3 or greater and an odd number.

3. The method of claim 2, wherein the parameter is selected from the group consisting of output current, output voltage and combinations thereof.

4. The method of claim 1, wherein the at least one statistical moment is a third statistical moment of a measured signal from the power converter.

5. The method of claim 4, wherein the third statistical moments are represented by the group consisting of load voltage, load current, source voltage and source current.

6. The method of claim 1, wherein the method further comprises a map of possible conditions of a measured signal and a third moment of the measured signal.

7. The method of claim 1, wherein the method provides information about the nature of the fault.

8. The method of claim 1, wherein the method provides information about the location of the fault.

9. The method of claim 1, wherein the method detects the fault in milliseconds.

10. The method of claim 1, wherein the output parameter is measured from a sensor.

11. A system for detecting a fault in a converter system comprising: a power converter system;a means for diagnosing a fault by monitoring continuously an output parameter at the power converter; anda means for obtaining at least one statistical moment of a sampled window of the continuously monitored output parameter.

12. The system of claim 11, wherein output parameter is measured from a sensor selected from the group consisting of current sensor, voltage sensor and combinations thereof.

13. The system of claim 11, wherein the at least one statistical moment is provided by a mean of a moving sampled window measure as compared with a current measure from a defined sample window size.

14. The system of claim 11, wherein the power converter is in operable communication with a computation device.

15. The system of claim 11, wherein the fault is represented by a cross-variance matrix expression for an nth order moment, wherein n is 3 or greater and an odd number.

16. The system of claim 14, wherein the system parameters are selected from the group consisting of output capacitor, inductor, duty cycle, converter output voltage, converter output current, converter input current, converter input voltage, system output port parameters, and system input port parameters.

17. A method for detecting a fault in a power converter system comprising: representing the fault by a cross-variance matrix of nth order statistical moments of power converter parameters, wherein n is 3 or greater and the statistical moments are selected from the group consisting of load voltage, load current, source voltage and source current.

18. A vehicle for detecting a fault in a power converter system comprising: a vehiclea power converter operable to drive the vehicle; anda fault detection system operable with the power converter, wherein the fault detection system continuously monitors and an output parameter of the power converter and represents the fault by a cross-variance matrix of nth order statistical moments of the output parameters.

19. The vehicle of claim 18, wherein n is 3 or greater and an odd number.