Method and circuit for detecting a short circuit of a resolver exciter line to ground or to the operating voltage

Patent metadata

Field	Value
Publication number	US-10359467-B2
Application number	US-201615737485-A
Country	US
Kind code	B2
Filing date	Jun 7, 2016
Priority date	Jun 18, 2015
Publication date	Jul 23, 2019
Grant date	Jul 23, 2019

Abstract

A method for detecting a short circuit ( 10 ) of a resolver exciter line ( 11, 12 ) comprising the steps of:
measuring ( 31 ) the excitation voltage (U(t i ) for the resolver ( 16 ) at a number of points in time during each excitation period;
determining ( 32 ) the amplitude of the excitation voltage;
starting a diagnostic mode ( 33 ) having the following steps ( 34 bis 37 ) if the amplitude of the excitation voltage does not reach a first threshold value;
retrieving ( 34 ) the time-dependent voltage curves U H (t i ) of the first and the second exciter line (H; 11 ) with respect to ground at the number of points in time;
calculating ( 35 ) the amplitudes and the offset values of the time-dependent voltage curves;
identifying ( 36 ) the exciter line that has a short circuit by determining that the calculated amplitudes do not exceed a second threshold value;
identifying ( 37 ) the potential to which the short-circuited line (H or L) can be connected by comparing the offset values to third threshold values.

First claim

The invention claimed is:

1. A method for detecting a short in a resolver excitation line, the method comprising:
measuring an excitation voltage of a periodic excitation signal for the resolver across first and second excitation lines of the resolver at a multiplicity of times during each excitation period of the excitation signal;
ascertaining an amplitude of the excitation voltage based on the measured values of the excitation voltage;
starting a diagnosis mode having the following steps when the amplitude of the excitation voltage does not reach a first threshold value:
calling up a time-dependent voltage profile of each of the first and second excitation lines referenced to ground at the multiplicity of times;
computing an amplitude value and an offset value of each of the time-dependent voltage profiles;
identifying the excitation line that has a short by determining the time-dependent voltage profile for which the computed amplitude value does not exceed a second limit value; and
identifying a potential to which the shorted excitation line can be pulled by comparing the offset value of the time-dependent voltage profile of the shorted excitation line with third limit values.

2. The method as claimed in claim 1 , wherein the measuring is effected by virtue of a first connection of the first excitation line and a second connection of the second excitation line being connected to respective inputs of an AD converter.

3. The method as claimed in claim 1 , wherein the ascertaining of the amplitude of the excitation voltage is effected by virtue of a maximum and a minimum of the measured values of the excitation voltage being ascertained for each excitation period and the amplitude being formed by half the difference between the ascertained maximum and minimum.

4. The method as claimed in claim 1 , wherein the calling up of the voltage profile of the first excitation line referenced to ground is effected by virtue of a first input of a first AD converter, to which a first connection of the first excitation line is connected, and a second input thereof being at ground potential at least for a measurement time of the first AD converter,
and wherein the calling up of the voltage profile of the second excitation line referenced to ground is effected by virtue of a first input of a second AD converter being at ground potential at least for the measurement time of the second AD converter and a second input thereof being connected to a second connection of the second excitation line.

5. The method as claimed in claim 1 , wherein the computing of the amplitude value and the offset value of each time-dependent voltage profile is effected by virtue of a maxima and a minima of the time-dependent voltage profile being ascertained, the amplitude value being computed by virtue of the difference between the ascertained maxima and the minima of the time-dependent voltage profile, and the offset value being computed by virtue of the sum of the ascertained maxima and the minima of the time-dependent voltage profile.

6. The method as claimed in claim 1 , wherein the identifying of the potential to which the shorted excitation line can be pulled is effected by virtue of the offset value of the time-dependent voltage profile of the shorted excitation line being compared with a threshold value for a ground potential and with a threshold value for an operating voltage potential.

7. A circuit for detecting a short in an excitation line of a resolver, the circuit comprising:
a control apparatus having a processor, power stages, first connections for providing signals to excitation lines for an excitation coil of the resolver and second connections for connecting signal lines for signals of sine and cosine coils of the resolver, and first and second AD converters having inputs connected to the second connections of the control apparatus and having outputs readable by the processor for evaluation thereby;
the excitation lines to be diagnosed that couple the first connections to the excitation coil of the resolver;
the signal lines for the sine and cosine signals provided by the resolver, which couple the resolver to the second connections of the control apparatus;
a third AD converter, first and second inputs of which are connected to respective ones of the first connections for the excitation lines;
one of:
a fourth and a fifth AD converter, each having a first input that is connected to ground and a second input that is connected to a respective one of the first connections for the excitation lines;
and:
two electronic switches that are respectively inserted between the connections for the excitation lines and the first and second inputs of the third AD converter, the switches being set up such that they respectively disconnect an input of the third AD converter from the corresponding excitation line and temporarily connect this input to ground; and

a display or memory device for displaying or storing information identified by the processor that incorporates detecting of a short in one of the excitation lines of the resolver and denoting of the shorted line and a potential to which the shorted line can be pulled.

8. The circuit as claimed in claim 7 , wherein the third, fourth and fifth AD converters, or the third AD converter and the two electronic switches, are integrated in the control apparatus.

Assignees

• Bosch Gmbh Robert

Inventors

• Lechner Benjamin
• Raichle Daniel
• Zirkel Daniel
• Ungermann Michael

Classifications

• G01D18/00

  Testing or calibrating apparatus or arrangements provided for in groups G01D1/00 - G01D15/00 · CPC title

• G01D5/20

  by varying inductance, e.g. by a movable armature · CPC title

• G01D5/2291 Primary

  Linear or rotary variable differential transformers (LVDTs/RVDTs) having a single primary coil and two secondary coils · CPC title

• G01R31/025

  Physics · mapped topic

• G01R31/2829 Primary

  Testing of circuits in sensor or actuator systems (testing of apparatus for measuring electric or magnetic variables G01R35/00; testing of indicating or recording apparatus G01D; in airbag systems B60R21/0173; checking gas analysers G01N33/007; monitoring or fail-safe circuits for electromagnets H01F7/1844) · CPC title