RU2598309C1 - Method of determining angle of rotor rotation of angle sensor of sine-cosine rotary transformer type - Google Patents

Abstract

FIELD: automatic control.

SUBSTANCE: invention relates to automatic monitoring and control and can be used in a modern electric drive to create a digital angle converter. Method is based on software-hardware demodulation of output amplitude-modulated signals (AMS) from the angle sensor of a sine-cosine rotary transformer type. In the method, due to integration of rectified signals of carrier components of sine and cosine AMS, determined are envelopes of positive parts of rectified signals of the carrier components of sine and cosine of AMS, and those envelopes amplitudes are converted into a digital code. Codes of amplitudes of envelopes of positive parts of rectified signals of the carrier components of sine and cosine AMS are used to determine envelopes amplitudes codes of the carriers of sine and cosine AMS, and their sign is determined by the level of signals from magnetic field sensors.

EFFECT: technical result is faster operation.

1 cl, 2 dwg

Description

The invention relates to the field of automatic control and regulation and can be used in a modern electric drive to create a digital angle converter.

Known digital angle converter (CPU), which contains an induction angle sensor, the first and second functional digital-to-analog converters, the first, second, third, fourth and fifth summing amplifiers, the first and second subtracting amplifiers, the first, second and third switches, the first and second blocks digital inverters, first, second and third digital inverters, digital-to-analog converter, reversible counter, driver of control signals of the reversible counter, corrective link, first, second, third and four fourth demodulators, first, second and third integrating links, first, second, third, fourth, fifth and sixth controlled analog inverters, first and second amplifiers-shapers, reprogrammable memory, analog-to-digital converter, amplitude-frequency normalizer (RF patent No. 2259631, H03M 1/48, published August 27, 2005).

The disadvantages of this CPU are the following.

The conversion speed is low due to the principle of compensation of the module of the magnitude of the voltage mismatch by the pulse sequence, which is fed to the counting input of the reversible counter and several integrating links used in the circuit, since any real integrating link is a delayed link.

The bulkiness of the device. Its functional diagram contains more than 40 blocks and, as a consequence of this, the complexity of its practical implementation

Any correction of the angular position of the sensor is complicated due to the need to modify the ROM for this.

The scheme does not take into account possible changes in the sensor parameters in the dynamic mode of its operation, for example, a change in the transformation coefficient during heating.

The closest to the results obtained is the method of operation of the digital-to-analog converter (CPU), which is taken as a prototype, it includes: an excitation voltage generator, the output of which is connected to the excitation winding of a two-phase induction angle sensor (DU) of the type sine-cosine rotary transformer (SCRT) ); SCWT receiver, the reference input of which is connected to the output of the excitation voltage generator, the sine and cosine inputs are connected respectively to the sine and cosine outputs of the two-phase induction angle sensor, and the output is connected to the voltage-frequency converter; a reversible counter, the input of which is connected to the output of the voltage-frequency converter, and the output with the digital input of the SKVT receiver, an additional first rectifier is introduced, the input of which is connected to the output of the excitation voltage generator; a second rectifier, the input of which is connected to the cosine output of the two-phase induction angle sensor; an adder, the first and second inputs of which are connected respectively to the outputs of the first and second rectifiers, and the output is connected to an amplifier; an analog-to-digital converter, the information input of which is connected to the output of the amplifier, and the reference input is connected to the output of the first rectifier; a controller, the first and second inputs of which are connected respectively to the outputs of the reversible counter and the output of the analog-to-digital converter, and the output is connected to the bus of the output code N. Moreover, in the digital angle converter, the SKVT receiver consists of an electronic analog, the first, second and third comparators, the first and the second D-flip-flops, a detector with an output low-pass filter, the first and second analog inverters and an analog adder. The output of the excitation voltage generator is connected to the first input of the third comparator, as well as the second input of the third comparator through a detector with an output low-pass filter; the sine output of the two-phase induction angle sensor is connected to the first input of the electronic analog, the analog input of the first analog inverter and the first input of the first comparator, the second input of which is connected to the zero potential bus; the cosine output of the two-phase induction angle sensor is connected to the second input of the electronic analog, the analog input of the second analog inverter and the second input of the second comparator, the first input of which is connected to the zero potential bus; the output of the first comparator is connected to the information input of the first D-trigger, the clock input of which is connected to the output of the third comparator, and the output to the control input of the first analog inverter; the output of the second comparator is connected to the information input of the second D-trigger, the clock input of which is connected to the output of the third comparator, and the output to the control input of the second analog inverter; the outputs of the first and second analog inverters through an analog adder are connected to the second input of the phase detector, the first input of which is connected to the output of the electronic analog, and the output through the voltage-frequency converter is connected to the control input of the binary reversible counter, the bit outputs of which are connected to the corresponding digital inputs of the electronic analog (RF patent No. 2533305, H03M 1/64, published November 20, 2014).

Common to this invention and the proposed method is that the conversion result does not depend on the possible mismatch of the phases of the excitation voltage of the angle sensor and its output voltages, and also that the conversion result is constantly adjusted when the transformation coefficient changes, for example, when the ambient temperature changes.

The disadvantages of the prototype include the following:

- the limited performance of the device due to the fact that when it is in the follow-up mode, each measurement cycle must end by setting the output of the reversible counter to a code value N, under which the condition of identical values of the angle of rotation of the sensor and N is satisfied by supplying the counter with the number of pulses proportional to a mismatch that is not optimal over time.

- redundancy of elements that are used to reduce the conversion error due to changes in the transformation coefficient.

The aim of the invention is to provide a method for determining the angle of rotation of the rotor of an angle sensor such as a sine-cosine rotary transformer, which due to the minimum sufficient set of hardware and software transformations of its output signals will improve performance and reduce the overall dimensions of the angle determination device implemented by this method.

The problem is solved in that in the method for determining the angle of rotation of the rotor of the angle sensor type sine-cosine rotating transformer, based on the conversion of the output signals from it into a digital code, regardless of the phase mismatch between the excitation voltage and the output signals and with constant correction of the conversion results at a change in its transformation coefficient associated with a change in ambient temperature, the sinus and cosine amplitude-modulus coming from the angle sensor The bath signals (AMS) are fed to the first and second rectifiers, where they are rectified, and from them are fed to the first and second integrators, where the envelopes of the positive parts of the bearing components of the sine and cosine AMS are received from the rectified signals, the signals from the first and second integrators are sent to the first and the second analog-to-digital converters, respectively, where the amplitudes of the envelopes of the positive parts of the bearing components of the sine and cosine AMCs are converted into digital codes, which are transmitted to the blocks of definition codes og The incoming carrier components of the sine and cosine AMCs, these blocks also receive discrete signals from the first and second magnetic field sensors, respectively, which, in turn, receive a signal from a magnet that rotates synchronously with the rotor of the angle sensor, the magnetic field sensors are thus positioned relative to the poles of the magnet and the position of the rotor of the angle sensor so that the half-periods of the signals from the first and second magnetic field sensors coincide in phase with the half-periods of the envelopes of the bearing components of the sinus and cosine respectively, in the blocks of determining the envelope codes of the bearing components of the sine and cosine AMS from the amplitude codes of the envelopes of the positive parts of the bearing components of the sine and cosine AMS, the codes of the amplitudes of the envelopes of the bearing components of the sine and cosine AMS are determined, respectively, and the sign is determined by the level of discrete signals from the magnetic field sensors of these codes, which allows one to determine the amplitudes of the envelopes of the bearing components of the sine and cosine AMSs over the entire period of their passage, from the The distribution of envelope codes of the bearing components of the sine and cosine AMS codes corresponding to the envelopes of the bearing components of the sine and cosine AMS are sent to the block for calculating the rotor angle code, where they calculate the code corresponding to the angle of rotation of the rotor of the angle sensor according to the formula:

θ = arctan (Uc / Uк),

where θ is the angle of rotation of the angle sensor,

Uc is the amplitude of the envelope of the sine amplitude-modulated signal at the time of measurement,

Uк is the amplitude of the envelope of the cosine amplitude-modulated signal at the time of measurement.

To demonstrate the essence of the proposed method of converting an angle into a digital code, a structural diagram of the device is proposed, which is shown in FIG. 1. In FIG. Figure 2 shows the curves that interpret the process of converting the rotation angle into code.

The device contains:

1 - generator;

2 - angle sensor (DU) type sine-cosine rotating transformer (SCWT);

3 - the first rectifier;

4 - magnet;

5 - the second rectifier;

6 - the first integrator;

7 - the first magnetic field sensor;

8 - second magnetic field sensor;

9 - second integrator;

10 - the first analog-to-digital Converter (ADC 1);

11 - the second analog-to-digital Converter (ADC 2);

12 - block definition codes of the envelope of the carrier component of the sine amplitude-modulated signal (AMC);

13 - block computing code angle of rotation of the rotor SKVT;

14 - block definition codes envelope carrier component of the cosine AMC.

It should be added that the combination of blocks 10 ... 14 can be implemented on a microcontroller such as STM32F103X or STM32F105X.

The method is implemented as follows.

The field winding of the angle sensor ДУ 2 of type SKVT is supplied from the generator 1 by voltage Uв, the shape of which is shown in FIG. 2.

The bearing components of the sine and cosine AMS come from the remote control 2 to the first 3 and second 5 rectifiers. In FIG. 2, these signals are designated as Uns and Uns.

The signals from the rectifiers, which in FIG. 2 are designated as Unsv and Unkv, they enter the first 6 and second 9 integrators, where from them the envelopes of the positive parts of the bearing components of the sine and cosine AMS are obtained, respectively. These envelopes in FIG. 2 are designated as Uns and Uns. The signals from the integrators are fed to the first 10 and second 11 analog-to-digital converters, respectively, where the amplitudes of the envelopes of the positive parts of the bearing components of the sine and cosine AMCs are converted into digital codes.

The first magnetic field sensor 7 and the second magnetic field sensor 8 receive a signal from the magnet 4, which rotates synchronously with the rotor of the angle sensor 2. The magnetic field sensors 7, 8 are thus positioned relative to the poles of the magnet and the position of the rotor of the angle sensor 2, so that the half-cycles of the signals from the first 7 and the second 8 magnetic field sensors coincided in phase with the half-periods of the envelopes of the bearing components of the sine and cosine AMS, respectively, for example, a high level of the signal from the magnetic field sensor 7 coincides in phase with positive part of the envelope period of the carrier of the sinus AMS, and the low level from the magnetic field sensor 7 coincides in phase with the negative part of the period of the envelope of the carrier of the sinus AMS and so that the signal fronts from the magnetic field sensors 7, 8 coincide with the transition points where the amplitudes of the envelopes change their sign to opposite.

Codes from the first 10 and second 11 analog-to-digital converters and signals from the first and second magnetic field sensors, which are in FIG. 2 are designated as Ump1 and Udmp2, and are supplied to the block for determining the envelope codes of the carrier component of the sine AMC 12 and the block for determining the codes for the envelope of the carrier component of the sine AMC 14, respectively. In these blocks, from the codes that come from blocks 10 and 11 and which determine the amplitude codes of the envelopes of the positive parts of the bearing components of the sine and cosine AMSs, respectively, determine the codes of the amplitudes of the envelopes of the bearing components of the sine and cosine AMSs, and by the signal level from the first 7 and second 8 sensors magnetic fields determine the sign of these codes. For example, the measured values of the amplitude of the envelopes of the positive parts of the bearing components of the sine and cosine AMSs in the high phase of the signal from the magnetic field sensor 7, 8 are determined as positive, and their measured values in the low phase of the signal from the magnetic field sensors 7, 8 are determined as negative. From the points that correspond to the obtained codes, it is possible to interpolate the envelopes of the bearing components of the sine and cosine AMCs, which in FIG. 2 are designated as Uc and Uk. The points on these curves, designated as TP1 ... TP9, are located on the fronts of the signals from the magnetic field sensors and are transition points where the envelopes change their sign to the opposite.

The process of isolating the Uc and Uk curves in this method is inherently balanced demodulation of the sine and cosine AMCs coming from the remote control 2. It is produced regardless of the phase of the voltage supplying it.

Knowing the values of the amplitudes of the envelopes of the sine and cosine AMCs Uc and Uk at each measurement allows the microcontroller to calculate the angle of rotation of the remote control 2 by the formula:

θ = arctan (Uc / Uк),

where θ is the angle of rotation of the shaft DU 2;

Uc is the amplitude of the envelope of the sinus AMS at the time of measurement;

Uк is the amplitude of the envelope of the cosine AMS at the time of measurement.

The maximum values of the amplitudes of the envelopes of the sine Uc and cosine Uc AMC, as they are determined in the first 10 and second 11 analog-to-digital converters, respectively, are compared with their initial values, which are stored in the memory of the microcontroller. If these values differ from those measured at the beginning of the work, they are programmed by the microcontroller's computational tools, which minimizes the conversion error when the transformation coefficient of the remote control 2 changes when various external factors act on it. Any additional hardware to solve this specific problem, as proposed in the prototype, when using this method of angle conversion is not used.

Claims (1)

A method for determining the angle of rotation of a rotor of an angle sensor such as a sine-cosine rotary transformer (SCRT), based on the conversion of the output signals from it into a digital code, regardless of the phase mismatch between the excitation voltage and the output signals and with constant correction of the conversion results when changing its transformation coefficient associated with a change in ambient temperature, characterized in that the output from the angle sensor is a sine and cosine amplitude-modulated signal s (AMS) are fed to the first and second rectifiers, where they are rectified, and from them are fed to the first and second integrators, where the rectified signals are converted into envelopes of the positive parts of the bearing components of the sine and cosine AMS, which are fed to the first and second analog-to-digital converters respectively, where the envelopes of the positive parts of the bearing components of the sine and cosine AMS are converted into digital codes, which are sent to the blocks for determining the codes of the envelopes of the bearing components of the sine and cosine A MS, respectively, these blocks also receive discrete signals from the first and second magnetic field sensors, respectively, which receive a signal from a magnet that rotates synchronously with the rotor of the HLW, and the magnetic field sensors are thus positioned relative to the poles of the magnet and the position of the rotor of the HLW, so that the signal half-periods from the first and second magnetic field sensors coincided in phase with the half-periods of the envelopes of the bearing components of the sine and cosine AMS, respectively, and that the signal fronts from the sensors are magnetically of the field coincided with the transition points, where the envelopes change their sign to the opposite, in the determination blocks of the envelope codes of the bearing components of the sine and cosine AMSs, from the amplitudes codes of the envelopes of the positive parts of the bearing components of the sine and cosine AMSs, the codes of the amplitudes of the envelopes of the bearing components of the sine and cosine AMS are determined respectively, and the level of discrete signals from the magnetic field sensors determines the sign of these codes, which allows you to determine the amplitude of the envelopes of the bearing components of the sinus and cosine AMCs for the entire period of their passage, from the blocks for determining the envelope codes of the bearing components of the sine and cosine AMCs, the codes corresponding to the amplitudes of the envelopes of the bearing components of the sine and cosine AMCs are sent to the block for calculating the rotor angle code, where the code corresponding to the rotation angle is calculated from them angle sensor rotor according to the formula:
θ = arctan (Uc / Uк),
where θ is the angle of rotation of the angle sensor,
Uc is the amplitude of the envelope of the sine amplitude-modulated signal at the time of measurement,
Uк is the amplitude of the envelope of the cosine amplitude-modulated signal at the time of measurement.

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