METHOD AND CIRCUIT FOR DETECTING AN OPEN LINE OF THE SINE/COSINE RECEIVER COIL OF A RESOLVER

• US 20180111485A1
• Filed: 06/07/2016
• Published: 04/26/2018
• Est. Priority Date: 06/18/2015
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Lechner, Benjamin, Zirkel, Daniel, Raichle, Daniel, Ungermann, Michael
• Granted Patent: US 10,639,999 B2
• Time in Patent Office: Days
• CPC Class Codes: B60L 3/0038 relating to sensors
• CPC Class Codes: B60L 3/0061 relating to electrical machines
• CPC Class Codes: G01B 7/30 for measuring angles or tapers; for testing the alignment of axes
• CPC Class Codes: G01D 1/08 over fixed periods of time
• CPC Class Codes: G01D 1/10 giving differentiated values
• CPC Class Codes: G01D 18/00 Testing or calibrating apparatus or arrangements provided for in groups G01D1/00 - G01D15/00
• CPC Class Codes: G01D 5/2233 constituting a short-circuiting element
• CPC Class Codes: G01D 5/2291 Linear or rotary variable differential transformers (LVDTs/RVDTs) having a single primary coil and two secondary coils
• CPC Class Codes: G01R 19/25 using digital measurement techniques
• CPC Class Codes: G01R 21/133 by using digital technique

Abstract

A method for detecting an open line (10) of a receiver coil (17; 18) of a resolver (16) comprises—providing a pull-up resistor (R₁; R₃) and a pull-down resistor (R₂; R₄) at the terminals (7a, 7b; 8a, 8b) on a control device (1) for the signal lines (13a, 13b; 14a, 14b) of the receiver coil (17; 18);—measuring the voltage between the two signal line terminals (7a, 7b; 8a, 8b) of the receiver coil at two sampling times provided symmetrically at the middle of the excitation period;—calculating an offset value by calculating an average value that comprises the measured values measured at the two sampling times in an excitation period; and—identifying an open line (10) if the offset value exceeds a threshold value.

Claims

1. A method for detecting an open signal line of a receiver coil of a resolver, the method comprising:

providing a pull-up resistor and a pull-down resistor which are connected with their one end to terminals for the signal lines;

measuring the voltage between the two signal line terminals of the receiver coil at at least two sampling times located symmetrically with respect to the center of the exciter period;

calculating an offset value by forming a mean value which comprises the measurement values at the two sampling times of an exciter period; and

identifying an open line if the offset value exceeds a threshold value.

2. The method as claimed in claim 1, wherein the pull-up resistor and the pull-down resistor are supplied at their other end with a voltage potential which differ by a constant amount from the other which is smaller than the measuring range of the AD converter for the measurement values of the receiver coil.

3. The method as claimed in claim 1, in which the calculating of the offset value takes into consideration the measurement values at the two sampling times of only one individual exciter period.

4. The method as claimed in claim 1, in which the calculating takes into consideration the measurement values at the two sampling times of a plurality of preceding exciter periods.

5. Circuit for detecting an open line of a receiver coil of a resolver, the circuit comprising:

a control device with a processor, power stages, first terminals for providing signals at the exciter lines to the exciter coil of the resolver and second terminals for connecting the signal lines for the signals of the sinusoidal and the cosinusoidal coil;

two AD converters which are connected to the second terminals of the control device and the outputs of which can be read and evaluated by the processor;

the exciter lines which couple the first terminals Or to the exciter coil of the resolver;

the signal lines to be diagnosed for the sinusoidal and cosinusoidal signals provided by the resolver, which couple the resolver to the second terminals of the control device;

pull-up resistors which are connected with their one end to one of the terminals for the lines of the sinusoidal coil and the cosinusoidal coil and with their other end to a first direct-voltage potential; and

pull-down resistors which are connected with their one end to the other one of terminals for the lines of the sinusoidal coil and the cosinusoidal coil and with their other end to a second direct-voltage potential, the second direct-voltage potential being lower than the first direct-voltage potential, in such a manner that the voltage difference lies between and in the measuring range of the AD converters; and

a display and/or storage device for displaying or storing the information identified by the processor, into which the positive detection of an open line of one of the receiver coils of a resolver is included.

6. The circuit as claimed in claim 5, wherein the pull-up and the pull-down resistors are integrated into the control device.

7. The circuit as claimed in claim 5, wherein the resistance values of the pull-up resistors and the pull-down resistors are large compared with the ohmic resistance of the sinusoidal coil and of the cosinusoidal coil.