CN115452032A - Digital demodulation device and method for rotary transformer - Google Patents
Digital demodulation device and method for rotary transformer Download PDFInfo
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Abstract
A digital demodulation device and a method for a rotary transformer relate to the field of sensor testing, and the device comprises a rotary transformer module, a rotary transformer output sampling module, a synchronous multiplier module, a peripheral circuit module, an excitation signal sampling module, an envelope line demodulation module, a PWM wave generation module, a sine excitation signal duty ratio generation module, a phase-locked loop module and a system error compensation module; the method comprises the following steps: generating a sinusoidal excitation signal; acquiring an envelope curve of an output signal of the rotary transformer; acquiring an angle and a rotating speed through a phase-locked loop; compensating for system delays. The invention effectively reduces the angle delay, obviously reduces the quantization error, eliminates the direct current offset and the excitation delay, eliminates the dependence of the traditional numerical integration method on zero crossing point sampling, and reduces the non-orthogonal error.
Description
Technical Field
The invention relates to the field of sensor testing, in particular to a digital demodulation device and method for a rotary transformer.
Background
The rotary transformer is widely applied to the fields of motors and industrial control as a position sensor. The resolver may provide absolute angular position information as well as rotational speed information. A resolver consists of a rotating primary coil and an orthogonal secondary coil. The primary side coil is driven by an excitation signal, and the secondary side coil outputs a carrier containing sine and cosine information. It is usually necessary to use an analog demodulation chip of the resolver to convert the carrier analog signal output by the resolver into a digital signal containing angle information and rotation speed information. Compared with the traditional analog demodulation method, the digital demodulation method based on the controller MCU has the characteristics of low cost, high integration level and the like, and is increasingly used on the majority of motor controllers. The digital demodulation method needs to sample the output signal of the rotary transformer based on the on-chip ADC on the MCU, and generate a sinusoidal excitation signal through PWM and a peripheral filter to drive the rotary transformer.
The existing digital demodulation methods for the rotary transformer are mainly divided into two types: one is a demodulation method based on sampling points, and the other is a demodulation method based on a filter. In the conventional vertex-sampling demodulation method, the coupled excitation signal is removed by sampling when the excitation signal reaches the vertex of the amplitude value, so that the envelope curve output by the rotary transformer is obtained. The demodulation method only performs sampling once in each excitation signal period in practice, the Nyquist sampling theorem is not satisfied, a large amount of quantization errors are introduced, and the accuracy is low. In the demodulation method based on the filter, synchronous sampling and multiplication are used for increasing the frequency of the component of the excitation signal, and then the excitation signal is filtered by the filter; due to the introduction of the filter, the angle information has a large delay, and the synchronous angle information cannot be obtained in real time. Therefore, the filter-based method cannot be used for high-precision torque control applications, and the application range is narrow.
Disclosure of Invention
The present invention is directed to solve the above-mentioned deficiencies of the prior art, and provides a digital demodulation apparatus and method for a resolver, which can reduce the angle delay caused by the demodulation of the resolver, reduce the quantization error of the digital demodulation, and have high demodulation accuracy and wide application range.
The technical scheme for solving the existing problems is as follows:
a digital demodulation device of a rotary transformer is characterized by comprising a rotary transformer module, a rotary transformer output sampling module, a synchronous multiplier module, a peripheral circuit module, an excitation signal sampling module, an envelope line demodulation module, a PWM wave generation module, a sine excitation signal duty ratio generation module, a phase-locked loop module and a system error compensation module;
the sine excitation signal duty ratio generation module is connected with the PWM wave generation module and is used for controlling the PWM wave generation module to generate PWM waves carrying sine excitation signals;
the PWM wave generation module is connected with the peripheral circuit module, and the peripheral circuit module is used for filtering and amplifying power of the PWM wave to obtain a sinusoidal excitation signal;
the peripheral circuit module is connected with the rotary transformer module, and the rotary transformer module is used for outputting an analog signal generated by coupling angle information and a sinusoidal excitation signal;
the rotary transformer module is connected with the rotary transformer output sampling module, and the rotary transformer output sampling module is used for acquiring an output signal of the rotary transformer;
the excitation signal sampling module is connected with the peripheral circuit module and is used for collecting the output sine excitation signal;
the excitation signal sampling module and the rotary transformer output sampling module are respectively connected with the synchronous multiplier module, and the synchronous multiplier module is used for synchronously multiplying the output signal of the rotary transformer with the excitation signal;
the synchronous multiplier module is connected with the envelope demodulation module, and the envelope demodulation module is used for demodulating the envelope;
the envelope demodulation module is connected with the phase-locked loop module, and the phase-locked loop module is used for outputting the angle and the rotating speed in the envelope;
the phase-locked loop module is connected with the system error compensation module, the system error compensation module multiplies the rotating speed of the envelope line by the time delay of the system and then adds the multiplied rotating speed and the angle of the envelope line to obtain the electrical angle of the rotary transformer, and the rotating speed output by the phase-locked loop is the rotating speed of the rotary transformer.
The invention is further improved and is provided with a non-orthogonal disturbance compensation module, wherein the envelope line demodulation module is connected with the non-orthogonal disturbance compensation module, and the non-orthogonal disturbance compensation module is used for observing non-orthogonal errors and compensating the errors in the envelope line by using the non-orthogonal errors;
the peripheral circuit module described in the present invention includes a filter circuit and a power amplifier circuit.
The envelope demodulation module is a numerical value synchronous integrator, and demodulates the envelope by using a synchronous numerical value integration method.
A digital demodulation method for a rotary transformer is characterized by comprising the following steps:
generating a sinusoidal excitation signal:
controlling the duty ratio of the PWM wave generation module to modulate the carried sine excitation signalThe PWM wave of # n; filtering and amplifying the PWM wave to obtain a sinusoidal excitation signal: v exc_real ＝k gain sin(ω exc t)，k gain To amplify the gain, omega exc Is the frequency of the sinusoidal excitation signal;
b, acquiring an envelope curve of an output signal of the rotary transformer:
inputting a sine excitation signal into a rotary transformer, synchronously oversampling the sine excitation signal and an output signal of the rotary transformer, and synchronously multiplying the two signals to obtain the multiplied rotary transformer output as follows:
envelope demodulation is carried out on the multiplied output signals of the rotary transformer to obtain envelope signals (namely, sine envelope signals and cosine envelope signals) of sine output and cosine output of the rotary transformer:
c, obtaining the angle and the rotating speed through a phase-locked loop
The sine envelope line and the cosine envelope line are transmitted to a phase-locked loop, the differential of an angle is obtained through park conversion of the phase-locked loop and a proportional-integral controller, and the rotating speed is obtained through a filter of the phase-locked loop; the differential value output by the proportional-integral controller is integrated to obtain an angle; (phase locked loop output speed and Angle)
Step d, compensating system delay:
multiplying the system delay time and the rotating speed output by the phase-locked loop to obtain an angle compensation quantity, and adding the angle compensation quantity and the angle output by the phase-locked loop to obtain the electrical angle of the rotary transformer.
The system delay comprises a numerical integration delay, a phase-locked loop delay and a controller delay; the system delay time is as follows:
wherein the content of the first and second substances,
numerical integration delay, T PLL For phase-locked loop delay, T MCU Is the controller delay.
The invention further improves, and the error operation in the compensation envelope curve is carried out before the step c:
multiplying the obtained sine envelope curve and cosine envelope curve according to a formula
The controller used by the invention is based on an AURIX TC275 chip, has the dominant frequency of 200MHz, comprises a DS-ADC high-precision analog-to-digital converter module and a high-precision GTM pulse width modulation module, and outputs a sine excitation signal by using a filtering and amplifying circuit consisting of a second-order operational amplifier.
The invention has the beneficial effects that: (1) The angle delay is effectively reduced by using a synchronous numerical integration method. (2) The quantization error is significantly reduced using a method combining oversampling and integration. And (3) fundamentally eliminating the direct current offset and the excitation delay. (4) The dependence of the traditional numerical integration method on zero-crossing sampling is eliminated. (5) The non-orthogonal compensation method is used for compensating errors in the envelope curve, and the non-orthogonal errors are reduced.
Drawings
Fig. 1 is a schematic structural diagram of functional modules of a resolver digital demodulating apparatus according to the present invention.
Fig. 2 is a graph of a sinusoidal excitation signal used in the present invention.
Fig. 3 is a graph comparing the sinusoidal envelope obtained by the present invention with the ideal sinusoidal envelope and the error graph thereof. The (a) is a comparison graph, and the (b) is an error graph.
Fig. 4 is a schematic structural diagram of functional modules of the non-orthogonal disturbance compensation module according to the present invention.
FIG. 5 is a diagram of the output angle of the PLL module of the present invention
And
a graph of the relationship of the functions.
FIG. 6 is a schematic structural diagram of a functional module for acquiring an angle and a rotation speed by the PLL module according to the present invention.
Fig. 7 is a graph of the resolver output signal of the present invention.
FIG. 8 is a graph comparing the angle obtained by the present invention with an ideal angle and an error graph thereof. The reference figure (a) is a comparative figure, and the error figure (b) is an error figure.
FIG. 9 is a graph comparing the rotational speed obtained by the present invention with an ideal rotational speed.
FIG. 10 is a diagram showing a comparison of cosine envelope errors before and after non-orthogonal compensation according to the method of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. The components of the embodiments of the present application, generally described and illustrated in the figures herein, can be arranged and designed in a wide variety of different configurations.
Thus, the following detailed description of the embodiments of the present application, presented in the accompanying drawings, is not intended to limit the scope of the claimed application, but is merely representative of selected embodiments of the application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined or explained in subsequent figures.
Background introduction of rotary transformers:
a resolver is an absolute position sensor that includes a primary coil and two orthogonal secondary coils. The input of the device is a sine excitation signal, and the output is sine and cosine signals with variable amplitude. The input signals are:
V exc ＝k gian sin(ω exc t) where k gian For amplitude gain of the excitation signal, ω exc Is the frequency of the excitation signal. Having an output signal of
V x And V y Respectively representing cosine and sine output signals, where k trans Representing the turns ratio, ω, of the resolver el The electrical speed of the rotary transformer during operation. The real-time absolute electrical angle and the electrical rotating speed of the rotary transformer can be obtained by converting the two output signals. In fact, due to the problems of manufacturing precision and time delay, the output of the rotary transformer has non-orthogonal error, excitation delay and direct current component, and the excitation signal output in the above formula is actually
Wherein beta is orth Representing non-orthogonal error, beta exc Denotes the excitation delay, V offset Denotes the direct current component, sin (ω) exc t) is the sine value of the excitation signal at time t, sin (ω) el t) is the sine value of the electrical speed of the rotary transformer during operation at time t.
The digital demodulation apparatus of the resolver shown in fig. 1 includes a resolver module 1, a resolver output sampling module 2, a synchronous multiplier module 3, a peripheral circuit module 4, an excitation signal sampling module 5, an envelope demodulation module 6, a non-orthogonal disturbance compensation module 9, a PWM wave generation module 7, a sinusoidal excitation signal duty cycle generation module 8, a phase-locked loop module 10, and a system error compensation module 11;
the sine excitation signal duty ratio generation module 8 is connected with the PWM wave generation module 7, and the sine excitation signal duty ratio generation module 8 is used for controlling the PWM wave generation module 7 to generate PWM waves carrying sine excitation signals according to the sine excitation signal angles;
the output end of the PWM wave generating module 7 is connected to the input end of the peripheral circuit module 4, and the peripheral circuit module 4 includes a filter circuit and a power amplifier circuit. The peripheral circuit module is used for filtering and power amplifying the PWM wave to obtain a sinusoidal excitation signal;
the output end of the peripheral circuit module 4 is connected with the input end of the rotary transformer module 1, and the rotary transformer module 1 is used for outputting an analog signal generated by coupling angle information and a sinusoidal excitation signal;
the output end of the rotary transformer module 1 is connected with the input end of the rotary transformer output sampling module 2, and the rotary transformer output sampling module 2 is used for collecting an output signal of the rotary transformer;
the input end of the excitation signal sampling module 5 is connected with the output end of the peripheral circuit module 4 and is used for collecting sinusoidal excitation signals output by the peripheral circuit module;
the output end of the excitation signal sampling module 5 and the output end of the rotary transformer output sampling module 2 are respectively connected with the input end of the synchronous multiplier module 3, and the synchronous multiplier module 3 is used for synchronously multiplying the output signal of the rotary transformer with a sinusoidal excitation signal;
the output end of the synchronous multiplier module 3 is connected with the input end of an envelope demodulation module 6, and the envelope demodulation module 6 is used for demodulating an envelope; in this embodiment, the envelope demodulation module 6 is a numerical synchronous integrator, and demodulates the envelope by using a synchronous numerical integration method to obtain a sine envelope and a cosine envelope;
the output end of the envelope demodulation module 6 is connected with the input end of the non-orthogonal disturbance compensation module 9, and the non-orthogonal disturbance compensation module 9 is used for observing non-orthogonal errors and compensating the envelope; as can be seen from fig. 4, the non-orthogonal disturbance compensation module includes a multiplier module, a Low Pass Filter (LPF) module, a per unit module, an anti-sine module, a compensation symbol adjustment module, an anti-cosine module, an adder module, and a cosine module, wherein a sine envelope output end and a cosine envelope output end of the envelope demodulation module are connected to an input end of the multiplier module, an output end of the multiplier module is connected to an input end of the Low Pass Filter (LPF) module, an output end of the Low Pass Filter (LPF) module is connected to an input end of the per unit module, an output end of the per unit module is connected to an input end of the anti-sine module, and an output end of the anti-sine module is connected to an input end of the compensation symbol adjustment module; the output end of the cosine envelope line of the envelope line demodulation module is connected with the input end of the cosine module, the output end of the cosine module and the output end of the compensation symbol adjusting module are respectively connected with the input end of the adder module, the output end of the adder module is connected with the input end of the cosine module, and the output end of the cosine module outputs compensated cosine envelope line signals.
The sine envelope output end of the envelope demodulation module 6 and the cosine module output end of the non-orthogonal disturbance compensation module 9 are connected with the input end of a phase-locked loop module 10, and the phase-locked loop module 10 is used for outputting an electrical angle and an electrical rotating speed in the envelope;
the output end of the phase-locked loop module 10 is connected with the input end of the system error compensation module 11, the system error compensation module 11 multiplies the rotating speed of the envelope curve by the time delay of the system and adds the multiplied rotating speed and the angle of the envelope curve to obtain the electrical angle of the rotary transformer, and the rotating speed output by the phase-locked loop is the electrical rotating speed of the rotary transformer.
The phase-locked loop module in this embodiment includes a park transform module, a proportional-integral controller module (PI), a low-pass filter module (LPF), and an integration module (1/s).
The sine envelope output end of the envelope demodulation module and the cosine module output end of the non-orthogonal disturbance compensation module are connected with the input end of the park transformation module, the q-axis voltage output end of the park transformation module is connected with the input end of the proportional-integral controller module, and the output end of the proportional-integral controller module is connected with the input ends of the low-pass filter module and the integral module respectively. The output end of a low-pass filter module of the phase-locked loop outputs the electric rotating speed of the rotary transformer, and the output end of an integration module outputs an electric angle; the output end of the park conversion module comprises a d-axis voltage output end and a q-axis voltage output end; the output end of the integral module is connected with the input end of the park transformation module and used as the feedback of the phase-locked loop angle.
The digital demodulation method of the rotary transformer realized by using the digital demodulation device of the rotary transformer comprises the following steps:
generating a sinusoidal excitation signal:
as shown in fig. 1, the generation of the sinusoidal excitation signal starts from the generation of the duty cycle of the PWM wave, and the sinusoidal excitation signal duty cycle generation module 8 generates the frequency ω of the excitation signal as needed exc Adjusting the duty ratio of the PWM wave, wherein the expression of the duty ratio is sin (omega) exc t). After the duty ratio required to be output is obtained, the sine excitation signal duty ratio generation module 8 controls the PWM wave generation module 7 to generate the PWM wave V exc (wave V) exc I.e. a PWM wave carrying a sinusoidal excitation signal). Then through the peripheral circuit module 4 pairs V exc Filtering and power amplifying to obtain sine wave V exc_real (sine wave V) exc_real Sinusoidal excitation signal), V exc_real ＝k gain sin(ω exc t)，k gain For the amplification gain, omega, of the power amplifier exc The frequency of the sinusoidal excitation signal. The peripheral circuit module 4 includes a filter circuit and a power amplifier circuit; wherein the filter is a low-pass filter with a cut-off frequency of 10 omega exc (ii) a In order to be able to obtain the sinusoidal excitation signal more accurately, the frequency of the PWM wave carrying the sinusoidal excitation signal output by the PWM wave generation module 7 is at least 100 ω exc . The filter in the peripheral circuit module 4 is an active low-pass filter, the filter and the power amplifier are both formed by using operational amplifiers, and the excitation signal V amplified by the power amplifier exc_real Is about 10V. FIG. 2 shows the excitation signal at an excitation frequency of 1k rad/s.
B, acquiring an envelope curve of an output signal of the rotary transformer:
firstly, the signal V output by the rotary transformer module 1 is synchronously oversampled by using the rotary transformer output sampling module 2 and the excitation signal sampling module 5 x And V y And a sinusoidal excitation signal V output from the peripheral circuit block 4 exc_real . The sampling ratio of oversampling isThe higher the oversampling sampling ratio, the faster the frequency of angle update, and the smaller the quantization error of the resulting result. After sampling, the signal V output by the rotary transformer module 1 x And V y With sampled sinusoidal excitation signal V exc_real Synchronous multiplication is carried out by using a synchronous multiplier module 3, namely, a result after synchronous multiplication is obtained in each sampling period. After the signal output by the rotary transformer and the sine excitation signal pass through the synchronous multiplier, the obtained result is
After synchronous multiplication, the output envelope of the resolver has been decoupled from the excitation signal. Considering the error in practice, the resolver sinusoidal output after passing through the synchronous multiplier is:
the output of the cosine output signal after passing through the synchronous multiplier is:
the output of the synchronous multiplier module 3 is transmitted to an envelope demodulation module 6 for envelope demodulation, and the envelope demodulation module 6 in this embodiment is a numerical synchronous integration module for envelope demodulation by using a numerical synchronous integration method. In the synchronous multiplier, the envelope has been decoupled from the excitation signal; the numerical value synchronous integration step needs to extract envelope information from an input synchronous multiplier signal. The integration interval of the numerical value synchronous integration is a period T of the sine excitation signal exc . Since the action flows of the numerical synchronous integration link for the cosine output and the sine output of the rotary transformer are the same, the numerical synchronous integration of the sine output is mainly analyzed below. The sinusoidal output after synchronous numerical integration is:
Step b1. Compensating for errors in the envelope
The resolver output signal contains various errors, in which both the excitation delay and the dc component are eliminated in step b. Step b1 compensates mainly for non-orthogonal errors. Therefore, a non-orthogonal disturbance compensation module 9 based on triangular transformation is designed, and a specific functional block diagram of the non-orthogonal disturbance compensation module 9 is shown in fig. 4.
And c, multiplying the sine envelope curve and the cosine envelope curve obtained in the step b to obtain a decoupled non-orthogonal error sine function:
filtering the non-orthogonal error sine function by a Low Pass Filter (LPF) and an arcsine function to obtain a non-orthogonal delay beta orth 。
Because the differential of the inverse cosine function and the cosine function is different in different angle intervals, the cosine envelope curve of the rotary transformer cannot be directly compensated, and therefore the compensated sign needs to be adjusted according to different angles. The link function for compensation is:
when the resolver angle is ((2 k-1) pi, 2k pi) k e N, the differential of the cosine function is positive and the differential of the inverse cosine function is negative, the differential signs of the two functions not being the same. Therefore, when the angle of the resolver is within this interval, the compensated angle should be a positive delay, so n is 0. When the value is (2 k pi, (2k + 1) pi), the differential of the cosine function is negative, the differential of the inverse cosine function is also negative, the signs of the differentials of the two functions are the same, the compensation angle is a negative delay, and therefore n is 1. However, if the sign of the compensation delay angle is abruptly changed at one point, a sudden change will be caused
The size of the disturbance peak greatly influences the stability of the system. Therefore, a buffer zone is generated before and after the symbol change angle by using the sigmoid function, and the function expression of compensation becomes:
wherein
The sign function of the compensation term is performed,
the initial value of the electrical angle output by the phase-locked loop module is 0.
C, obtaining the angle and the rotating speed through a phase-locked loop
After compensating for the envelope error, the sine envelope and the cosine envelope are used as inputs to the pll module 10. Fig. 6 is a block diagram of the acquisition angle and rotation speed of the phase locked loop. Wherein the expression of park transformation is:
after park conversion and a proportional integral controller pi, the differential of an angle can be obtained, and the electric rotating speed of the rotary transformer can be obtained after the low-pass filter of the phase-locked loop; the resulting angular differential is integrated to obtain the electrical angle.
Step d. Compensating for system delay
The digital demodulation system of the rotary transformer uses numerical integration, namely fixed integration. Thus introducing an integrated delay of half the period of the excitation signal:
in addition to this, there is a delay T of the phase-locked loop PLL And delay T of the controller MCU . Thus the delay of the system can be obtained as
It can be considered that the electrical rotational speed of the resolver is not changed in the system delay with short time, therefore, the system error compensation module 11 multiplies the rotational speed output by the phase-locked loop by the system delay to obtain the angle of system delay compensation, and adds the compensation angle to the output angle of the phase-locked loop to obtain the electrical angle of the resolver which is finally output by the system, where the electrical angle of the resolver is:
the invention adopts AURIX TC275 as the controller of the digital demodulation system of the rotary transformer. An active filter consisting of a second-order operational amplifier and a power amplification circuit are used as an excitation signal output topological circuit. The electrical speed of the rotary transformer in the experiment is 100rpm; the period of the excitation signal is 1kHz; the sampling frequency is 100kHz; the non-orthogonal delay introduced is 0.2 degrees. The resolver system is simulated by using an NI PXI set, wherein an FPGA-based board card PXIe-7846R is used for simulating the resolver, ideal envelope curve information, angle information and rotating speed information are provided, and can communication is carried out through a PXI-8512 board card.
Fig. 7 shows the sine and cosine signals output by the analog resolver according to the input excitation signal. Fig. 8 shows a comparison of the angle obtained by the digital demodulation system obtained by the present invention and an ideal angle; as can be seen, the method can better follow the ideal angle, and the error obtained under the working condition of 100RPM is 20.87arc min. FIG. 9 is a graph comparing the rotational speed obtained by the method of the present invention with an ideal rotational speed. As known from the figure, the invention can stably follow the ideal rotating speed, and the error between the obtained rotating speed and the ideal rotating speed is only 0.07rpm. Fig. 10 shows the comparison of cosine envelope errors before and after non-orthogonal compensation according to the method of the present invention, where the non-orthogonal compensation significantly reduces the errors.
In summary, the present invention provides a digital demodulation method for a resolver based on numerical synchronous integration. By using the envelope demodulation method of numerical value synchronous integration, the delay of the angle acquired by the digital demodulation system can be effectively reduced. The oversampling is used in combination with the integration, so that the quantization error in the sampling process can be reduced. The synchronous multiplier is matched with the integral element, so that excitation delay and a direct current component of the rotary transformer can be removed. Meanwhile, a synchronous multiplier is used for decoupling excitation and envelope signals before integration, and a zero-crossing detection link of the output of the rotary transformer is omitted. The method designs a disturbance observer based on triangular transformation, and the disturbance observer is used for compensating the non-orthogonal delay of the output of the rotary transformer. Meanwhile, a sigmoid-based join function is designed to smooth the compensated cosine envelope.
Claims (6)
1. A digital demodulation device of a rotary transformer is characterized by comprising a rotary transformer module, a rotary transformer output sampling module, a synchronous multiplier module, a peripheral circuit module, an excitation signal sampling module, an envelope line demodulation module, a PWM wave generation module, a sine excitation signal duty ratio generation module, a phase-locked loop module and a system error compensation module;
the sine excitation signal duty ratio generation module is connected with the PWM wave generation module and is used for controlling the PWM wave generation module to generate PWM waves carrying sine excitation signals;
the PWM wave generation module is connected with the peripheral circuit module, and the peripheral circuit module is used for filtering and amplifying power of the PWM wave to obtain a sinusoidal excitation signal;
the peripheral circuit module is connected with the rotary transformer module, and the rotary transformer module is used for outputting an analog signal generated by coupling angle information and a sinusoidal excitation signal;
the rotary transformer module is connected with the rotary transformer output sampling module, and the rotary transformer output sampling module is used for acquiring an output signal of the rotary transformer;
the excitation signal sampling module is connected with the peripheral circuit module and is used for collecting the output sine excitation signal;
the excitation signal sampling module and the rotary transformer output sampling module are respectively connected with the synchronous multiplier module, and the synchronous multiplier module is used for synchronously multiplying the output signal of the rotary transformer with the excitation signal;
the synchronous multiplier module is connected with the envelope demodulation module, and the envelope demodulation module is used for demodulating the envelope;
the envelope demodulation module is connected with the phase-locked loop module, and the phase-locked loop module is used for outputting the angle and the rotating speed in the envelope;
the phase-locked loop module is connected with the system error compensation module, the system error compensation module multiplies the rotating speed of the envelope line by the time delay of the system and then adds the multiplied rotating speed and the angle of the envelope line to obtain the electrical angle of the rotary transformer, and the rotating speed output by the phase-locked loop is the rotating speed of the rotary transformer.
2. The digital demodulation device of the rotary transformer according to claim 1, wherein a non-orthogonal perturbation compensation module is provided, the envelope demodulation module is connected with the non-orthogonal perturbation compensation module, the non-orthogonal perturbation compensation module is used for observing non-orthogonal errors, and the non-orthogonal errors are used for compensating errors in the envelope.
3. The resolver digital demodulating device according to claim 1 or 2, wherein the peripheral circuit block includes a filter circuit and a power amplifier circuit.
4. The resolver digital demodulating device according to claim 1 or 2, wherein the envelope demodulating module is a numerical synchronous integrator, and demodulates the envelope by a synchronous numerical integration method.
5. A digital demodulation method for a rotary transformer is characterized by comprising the following steps:
generating a sinusoidal excitation signal:
controlling the duty ratio of a PWM wave generation module to modulate a PWM wave carrying a sinusoidal excitation signal; the PWM wave is filtered and amplified to be positiveString excitation signal: v exc_real ＝k gain sin(ω exc t)，k gain To amplify the gain, omega exc Is the frequency of the sinusoidal excitation signal;
b, acquiring an envelope curve of an output signal of the rotary transformer:
inputting the sine excitation signal into a rotary transformer, synchronously oversampling the sine excitation signal and an output signal of the rotary transformer, and synchronously multiplying the two signals to obtain the multiplied rotary transformer output as follows:
envelope demodulation is carried out on the multiplied output signals of the rotary transformer to obtain envelope signals (namely, sine envelope signals and cosine envelope signals) of sine output and cosine output of the rotary transformer:
c, obtaining the angle and the rotating speed through a phase-locked loop
The sine envelope line and the cosine envelope line are transmitted to a phase-locked loop, the differential of the angle is obtained through park conversion of the phase-locked loop and a proportional-integral controller, and the rotating speed is obtained through a filter of the phase-locked loop; the differential value output by the proportional-integral controller is integrated to obtain an angle;
step d, compensating system delay:
multiplying the system delay time and the rotating speed output by the phase-locked loop to obtain an angle compensation quantity, and adding the angle compensation quantity and the angle output by the phase-locked loop to obtain the electrical angle of the rotary transformer.
The system delay comprises a numerical integration delay, a phase-locked loop delay and a controller delay; the system delay time is as follows:
wherein the content of the first and second substances,
numerical integration delay, T PLL For phase-locked loop delay, T MCU Is the controller delay.
6. The resolver digital demodulation method according to claim 5, wherein: the error compensation operation in the envelope curve is carried out before the step c:
multiplying the obtained sine envelope curve and cosine envelope curve according to a formula
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116539070A (en) * | 2023-07-04 | 2023-08-04 | 深圳砺驰半导体科技有限公司 | Digital decoding method, chip, system, vehicle machine and medium of rotary transformer |
| CN116827204A (en) * | 2023-08-30 | 2023-09-29 | 南京理工大学 | Servo motor rotary transformer decoding system based on low-energy carrier feedback |
| CN117792192A (en) * | 2024-02-23 | 2024-03-29 | 潍柴动力股份有限公司 | Method, device, equipment and medium for rotary soft decoding |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116539070A (en) * | 2023-07-04 | 2023-08-04 | 深圳砺驰半导体科技有限公司 | Digital decoding method, chip, system, vehicle machine and medium of rotary transformer |
| CN116539070B (en) * | 2023-07-04 | 2023-09-15 | 深圳砺驰半导体科技有限公司 | Digital decoding method, chip, system, vehicle machine and medium of rotary transformer |
| CN116827204A (en) * | 2023-08-30 | 2023-09-29 | 南京理工大学 | Servo motor rotary transformer decoding system based on low-energy carrier feedback |
| CN116827204B (en) * | 2023-08-30 | 2023-11-21 | 南京理工大学 | Servo motor rotary transformer decoding system based on low-energy carrier feedback |
| CN117792192A (en) * | 2024-02-23 | 2024-03-29 | 潍柴动力股份有限公司 | Method, device, equipment and medium for rotary soft decoding |
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