Decoding device and decoding method for rotary transformer

Abstract

The invention discloses a rotary transformer decoding device which comprises an integrator, a parallel integrator, a phase-locked loop and a second-order frequency-locked loop. The input end of the integrator is connected with the output end of the rotary transformer after demodulation is completed, and the integrator is used for obtaining a sinusoidal signal and a cosine signal which are demodulated and output by the rotary transformer and carrying out band-pass filtering on the sinusoidal signal and the cosine signal so as to compensate the amplitude and the phase of the sinusoidal signal and the cosine signal; the input end of the parallel integrator is connected with the output end of the integrator, and the parallel integrator is used for carrying out parallel band-pass filtering on the sine signal and the cosine signal after band-pass filtering so as to obtain and filter out each harmonic component; the second-order frequency-locked loop is connected with the integrator and the parallel integrator, obtains the center frequency of the sinusoidal signal and the center frequency of the cosine signal, and adjusts the center frequency of the integrator; the phase-locked loop is connected with the output of the parallel integrator, and is used for obtaining the angular position and angular frequency of a motor rotor according to the sine signal and the cosine signal after the parallel band-pass filtering. The method improves the calculation precision of the rotation angle of the motor, and also can guarantee the dynamic and static performances of the system.

Description

Technical Field

[0001] The present invention relates to the technical field of motor control, and in particular to a rotary transformer decoding device and a decoding method. Background Art

[0002] With the development of science and technology, permanent magnet synchronous motors are widely used in various industries due to their advantages such as high power density, high efficiency, wide speed regulation range, and small torque fluctuation. Vector control is currently widely used in permanent magnet synchronous motor control systems, and vector control requires accurate rotor position information. The resolver has the characteristics of high precision and high reliability, and can adapt well to harsh environments. The output signal of the resolver is an envelope signal, which contains motor speed and position information. It needs to be decoded by a decoding circuit to obtain a digital signal used by the power supply control system. This type of decoding circuit is a special analog-to-digital converter called a resolver-to-digital conversion (RDC).

[0003] Due to the body, installation and subsequent signal processing circuit of the resolver, certain errors will be introduced into the resolver output signal. In order to obtain high-precision motor rotor position, the errors need to be compensated.

[0004] For example: for amplitude and phase error compensation, a dual synchronous rotating coordinate transformation phase-locked loop scheme is generally used. This scheme has a certain suppression effect on amplitude and phase errors, but lacks harmonic processing; the public patent document (CN116678436A) proposes the use of a cascaded notch filter-frequency locked loop scheme to process harmonics, but its follow-up performance for dynamically changing motor speed is relatively poor. When applied to working conditions where the motor speed is constantly changing, the first-order frequency locked loop has a relatively poor effect on tracking the motor frequency, which will have a certain impact when processing harmonics through a cascaded notch filter; therefore, the current decoding scheme still has shortcomings in the harmonic processing scheme. Summary of the invention

[0005] The technical problem to be solved by the present invention is how to provide a technical solution for obtaining a high-precision motor rotor position through a rotary transformer.

[0006] In order to solve the above technical problems, the present invention provides a rotary transformer decoding device, including an integrator, a parallel integrator, a phase-locked loop and a second-order frequency-locked loop;

[0007] The input end of the integrator is connected to the output end of the resolver after demodulation, so as to obtain the sine signal and cosine signal output by the resolver demodulation, and perform band-pass filtering on the sine signal and cosine signal to compensate for the amplitude and phase of the sine signal and cosine signal;

[0008] The input end of the parallel integrator is connected to the output end of the integrator, and is used to perform parallel bandpass filtering on the sine signal and the cosine signal after bandpass filtering to obtain and filter out each harmonic component;

[0009] The second-order frequency-locked loop is connected to the integrator and the parallel integrator respectively, obtains the center frequency of the sine signal and the cosine signal, and adjusts the center frequency of the integrator;

[0010] The phase-locked loop is connected to the output of the parallel integrator and is used to obtain the motor rotor angular position and angular frequency according to the sine signal and cosine signal after the parallel bandpass filtering.

[0011] Preferably, the integrator includes a first integrator and a second integrator; the first integrator is used to obtain a sinusoidal signal demodulated and output by the rotary transformer, and to perform band-pass filtering on the sinusoidal signal to compensate for the amplitude and phase of the sinusoidal signal; the second integrator is used to obtain a cosine signal demodulated and output by the rotary transformer, and to perform band-pass filtering on the cosine signal to compensate for the amplitude and phase of the cosine signal.

[0012] Preferably, both the first integrator and the second integrator are second-order generalized integrators.

[0013] Preferably, the parallel integrator includes a first parallel integrator and a second parallel integrator; the first parallel integrator is used to perform parallel bandpass filtering on the sine signal after bandpass filtering to obtain and filter out the harmonic components of the sine signal; the second parallel integrator is used to perform parallel bandpass filtering on the cosine signal after bandpass filtering to obtain and filter out the harmonic components of the cosine signal.

[0014] Preferably, the first parallel integrator and the second parallel integrator are both parallel second-order generalized integrators.

[0015] The present invention also provides a resolver decoding method, which is performed by using the resolver decoding device described above, and includes:

[0016] Step S1, obtaining a sine signal and a cosine signal outputted by a rotary transformer after demodulation;

[0017] Step S2, performing bandpass filtering on the sine signal and the cosine signal to obtain a sine signal and a cosine signal with the same fundamental wave amplitude and orthogonal phase;

[0018] Step S3, obtaining the center frequency of the sine signal and the cosine signal, and adjusting the center frequency of the integrator;

[0019] Step S4, performing parallel bandpass filtering on the sine signal and cosine signal after bandpass filtering;

[0020] Step S5, obtaining the motor rotor angular position and angular frequency according to the sine signal and cosine signal after parallel bandpass filtering.

[0021] Preferably, in step S3, the method for adjusting the center frequency of the integrator is: the second-order frequency-locked loop obtains an estimated error based on the frequency difference of the sine signal or the cosine signal before and after band-pass filtering, and obtains the center frequency of the integrator based on the estimated error and the orthogonal signal of the estimated amount of the sine signal or the orthogonal signal of the estimated amount of the cosine signal, and adjusts the center frequency of the integrator based on the frequency of the sine signal or the cosine signal before band-pass filtering.

[0022] Preferably, in step S5, the method for obtaining the angular position of the motor rotor is: inputting the sine signal and cosine signal after parallel bandpass filtering into a phase-locked loop, and obtaining the input error of the phase-locked loop; and obtaining the angular position of the motor rotor according to the input error of the phase-locked loop and the rotor observation angular position output by the phase-locked loop.

[0023] Preferably, in step S5, the method for obtaining the motor rotor angular frequency is: determining the PI regulator parameters of the phase-locked loop according to the speed regulation range of the motor; inputting the sine signal and cosine signal after parallel bandpass filtering into the phase-locked loop to obtain the motor rotor angular frequency.

[0024] Compared with the prior art, according to the present invention, the positive-sequence components of the sine signal and the cosine signal are first extracted from the sine signal and the cosine signal demodulated and output by the rotary transformer through a double second-order generalized integrator; the influence of the unequal amplitude and non-orthogonal phase errors in the sine signal and the cosine signal demodulated and output by the rotary transformer is first eliminated, and the center frequency of the second-order generalized integrator is tracked and adjusted at the same time; and then the parallel second-order generalized integrator and the phase-locked loop angle tracking algorithm are used to filter out the specified harmonics in the sine signal and the cosine signal, thereby improving the accuracy of the motor rotation angle solution, and at the same time ensuring the dynamic and static performance of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments:

[0026] Figure 1 Schematic diagram of the structure of the rotary transformer decoding device of Example 1;

[0027] Figure 2 is a Bode diagram of the second-order generalized integrator of Example 2;

[0028] Figure 3 Schematic diagram of a second-order generalized integrator and a second-order frequency-locked loop of Example 2;

[0029] Figure 4 This is a schematic diagram of the phase-locked loop of Example 2. DETAILED DESCRIPTION

[0030] The following describes the implementation methods of the present invention through specific specific embodiments, and those skilled in the art can fully understand other advantages and technical effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through different specific implementation methods, and the details in this specification can also be applied based on different viewpoints, and various modifications or changes can be made without deviating from the overall design concept of the invention. It should be noted that the following embodiments and the features in the embodiments can be combined with each other in the absence of conflict. The following exemplary embodiments of the present invention can be implemented in a variety of different forms and should not be interpreted as being limited to the specific embodiments described herein. It should be understood that these embodiments are provided to make the disclosure of the present invention thorough and complete, and to fully convey the technical solutions of these exemplary specific embodiments to those skilled in the art.

[0031] Example 1

[0032] like Figure 1 As shown, this embodiment provides a rotary transformer decoding device, characterized in that it includes an integrator, a parallel integrator, a phase-locked loop and a second-order frequency-locked loop;

[0033] The input end of the integrator is connected to the output end of the resolver after demodulation, so as to obtain the sine signal and cosine signal output by the resolver demodulation, and perform band-pass filtering on the sine signal and cosine signal to compensate for the amplitude and phase of the sine signal and cosine signal;

[0034] The input end of the parallel integrator is connected to the output end of the integrator, and is used to perform parallel bandpass filtering on the sine signal and the cosine signal after bandpass filtering to obtain and filter out each harmonic component;

[0035] The second-order frequency-locked loop is connected to the integrator and the parallel integrator respectively, obtains the center frequency of the sine signal and the cosine signal, and adjusts the center frequency of the integrator;

[0036] The phase-locked loop is connected to the output of the parallel integrator and is used to obtain the motor rotor angular position and angular frequency according to the sine signal and cosine signal after the parallel bandpass filtering.

[0037] The integrator of this embodiment includes a first integrator and a second integrator, and both are second-order generalized integrators. The first integrator is used to obtain a sine signal demodulated and output by a rotary transformer, and to perform a band-pass filter on the sine signal to compensate for the amplitude and phase of the sine signal; the second integrator is used to obtain a cosine signal demodulated and output by a rotary transformer, and to perform a band-pass filter on the cosine signal to compensate for the amplitude and phase of the cosine signal.

[0038] The parallel integrators of this embodiment include a first parallel integrator and a second parallel integrator; the integrators used therein are also second-order generalized integrators.

[0039] The first parallel integrator is used to perform parallel bandpass filtering on the bandpass filtered sinusoidal signal to obtain and filter out the harmonic components of the sinusoidal signal; the first parallel integrator is Figure 1 The harmonic decoupling network composed of multiple second-order generalized integrators in the upper middle part.

[0040] The second parallel integrator is used to perform parallel bandpass filtering on the bandpass filtered cosine signal to obtain and filter out the harmonic components of the cosine signal. Figure 1 The harmonic decoupling network composed of multiple second-order generalized integrators in the middle and lower part.

[0041] The main purpose of the present invention is to suppress the influence of harmonic interference, unequal amplitude, non-orthogonal phase and other error factors on the angle solution of the sine signal and cosine signal demodulated and output by the rotary transformer, and improve the accuracy of the position information solution. In this embodiment, a double second-order generalized integrator (DSOGI) is used to extract the positive sequence components of the sine signal and the cosine signal, and the center frequency of the second-order generalized integrator is tracked and adjusted at the same time; a parallel second-order generalized integrator is used to eliminate the specified harmonics of the sine signal and the cosine signal after the positive sequence component is extracted, and the frequency of the sine signal and the cosine signal is fed back to the second-order generalized integrator through a second-order frequency-locked loop to form a closed-loop feedback network, and finally the amplitude deviation, phase deviation and harmonic error are eliminated, thereby improving the accuracy of the position information solution.

[0042] Example 2

[0043] This embodiment provides a resolver decoding method based on the resolver decoding device described in Embodiment 1.

[0044] The specific method includes the following steps:

[0045] Step S1, obtaining a sine signal and a cosine signal outputted by a rotary transformer after demodulation;

[0046] Step S2, performing bandpass filtering on the sine signal and the cosine signal to obtain a sine signal and a cosine signal with the same fundamental wave amplitude and orthogonal phase;

[0047] Step S3, obtaining the center frequency of the sine signal and the cosine signal, and adjusting the center frequency of the integrator;

[0048] Step S4, performing parallel bandpass filtering on the sine signal and cosine signal after bandpass filtering;

[0049] Step S5, obtaining the motor rotor angular position and angular frequency according to the sine signal and cosine signal after parallel bandpass filtering.

[0050] Each of these steps is described in detail below.

[0051] In step S1, a sinusoidal signal U containing harmonic components, unequal amplitudes, and non-orthogonal phase errors output by the resolver is obtained. sin and cosine signal U cos , specifically:

[0052]

[0053] Where U cos is the cosine signal after the resolver is demodulated, U sin is the sine signal demodulated by the resolver, V 1c and V 1s are the fundamental amplitudes of the cosine signal and the sine signal, σ 1c and σ 1s are the initial phases of the cosine signal and the sine signal, θ represents the ideal angle, V nc and V ns are the amplitudes of the harmonics in the cosine signal and the sine signal, σ nc and σ ns are the initial phases of each harmonic in the cosine signal and sine signal respectively, and n represents the harmonic order.

[0054] Ideally, the resolver outputs a sinusoidal signal U sin and cosine signal U cos Use a vector In fact, due to the influence of various non-ideal factors, The trajectory is an ellipse.

[0055] In step S2, the sine signal and the cosine signal are bandpass filtered to obtain:

[0056]

[0057] In the formula, is the cosine signal after bandpass filtering, is the sinusoidal signal after bandpass filtering, U′ c is the estimate of the cosine signal, qU′ c U′ c The orthogonal signal, U′ s is the estimator of the sinusoidal signal, qU′ s U′ s orthogonal signals.

[0058] From the above formula, we can see that if we can extract the positive sequence component V in the sine signal and cosine signal + cos(ω m t) and V + sin(ω m t), the errors caused by amplitude imbalance and phase non-orthogonality can be eliminated, thereby improving the accuracy of the rotor position angle.

[0059] like Figure 2 The second-order generalized integrator (SOGI) has the characteristics of no amplitude attenuation and no phase shift at the resonant frequency point. Therefore, in step S2 of this embodiment, the second-order generalized integrator (SOGI) can be used to extract the positive-sequence components of the sine signal and cosine signal of the rotary transformer to compensate for the amplitude and phase of the sine signal and cosine signal to obtain sine signals and cosine signals with the same amplitude and orthogonal phase.

[0060] The traditional second-order generalized integrator (SOGI) mainly includes two parts of output. Suppose the input signal is V, and the output signals are V′ and qV′. V′ is the estimated value of the input signal V, and qV′ is the orthogonal signal of V′.

[0061] The demodulated sine and cosine signals are sent to the second-order generalized integrator (SOGI) respectively, and the output signals in stable state are:

[0062]

[0063] By replacing U′ in the above formula c With qU′ s Subtracting can eliminate the negative sequence component Get the positive sequence component of the cosine signal; by replacing qU′ in the above formula c and U′ s Adding can eliminate negative sequence components Get the positive sequence component of the sinusoidal signal.

[0064] The positive sequence components extracted by the dual second-order generalized integrator (DSOGI) are:

[0065]

[0066] In the formula, is the sinusoidal signal after bandpass filtering, is the cosine signal after bandpass filtering, U′ s is the estimator of the sinusoidal signal, qU′ s U′ s The orthogonal signal, U′ c is the estimate of the cosine signal, qU′ c U′c orthogonal signals.

[0067] The output of the dual second-order generalized integrator (DSOGI) is used to compensate for the unequal amplitude and non-orthogonal phase errors in the demodulated sine and cosine signals of the resolver.

[0068] Since the motor speed changes dynamically, the center frequency ω′ of SOGI also needs to change accordingly. The main function of the second-order frequency-locked loop is to make the center frequency ω′ follow the sine and cosine signal frequency ω m The deviation eventually makes ω′=ω m , complete the frequency locking function, and m Feedback to the second-order generalized integrator (SOGI).

[0069] Use the second-order frequency-locked loop to obtain the frequency ω of the sine signal and cosine signal before bandpass filtering. m The estimated error ε1 between the frequency ω′ of the corresponding bandpass filtered sine signal and cosine signal and its corresponding estimated orthogonal signal qU′ s and qU′ c , get the center frequency ω′ of the second-order generalized integrator, ω′ is also the signal frequency of the second-order generalized integrator.

[0070] In step S4, the sine signal and the cosine signal obtained by the second-order generalized integrator are output to a parallel second-order generalized integrator, and the harmonic components in the sine signal and the cosine signal are filtered out.

[0071] The harmonic amplitude in the demodulated output signal of the resolver decays rapidly with the increase of the harmonic order, so the influence of the second and third harmonics is mainly considered. sin and cosine signal U cos The frequency of is known, and a parallel second-order generalized integrator harmonic decoupling network is designed to filter out the above high-order harmonics. The harmonic decoupling network causes a large phase shift at the harmonic frequency point, but a small phase shift for signals of other frequencies.

[0072] After filtering out the high-order harmonics through the harmonic decoupling network, the sine and cosine signals obtained are:

[0073]

[0074] From the above formula, we can see that U′ c is the cosine signal output by the harmonic decoupling network, U′ s The sinusoidal signal output by the harmonic decoupling network is an ideal sine and cosine signal containing the motor rotor angular frequency, and does not contain harmonic interference and amplitude inequality and phase non-orthogonal errors.

[0075] In step S5, the rotor angular position and rotor angular frequency are obtained according to the sine signal and cosine signal after bandpass filtering, that is, the sine signal and cosine signal output by the harmonic decoupling network are sent to the phase-locked loop to decode the rotor angular position and rotor angular frequency.

[0076] First, the phase detector link of the phase-locked loop is used to obtain the input error ε2 of the phase-locked loop according to the sine signal and cosine signal after bandpass filtering. The input error ε2 of the phase-locked loop satisfies:

[0077]

[0078] In the formula, is the rotor observation position output by the phase-locked loop, ε2 is the input error of the phase-locked loop, θ m is the motor rotor angular position.

[0079] Therefore, the rotor angular position can be observed based on the input error ε2 of the phase-locked loop and the output of the phase-locked loop. Decoding to obtain the motor's rotor angular position θ m .

[0080] The closed-loop transfer function G(s) of the phase-locked loop in this embodiment is:

[0081]

[0082] In the formula, k p , k i It is the proportional term and integral term of the PI regulator of the phase-locked loop.

[0083] Therefore, the bandwidth of the phase-locked loop can be set according to the speed regulation range of the motor to determine the k of the PI regulator. p , k i Parameters, then the sine signal and cosine signal output by the harmonic decoupling network are input into the PI regulator of the phase-locked loop, and the rotor angular frequency of the motor is obtained by decoding.

[0084] The present invention has been described in detail above through specific implementation modes and embodiments, but these do not constitute limitations of the present invention. Without departing from the principles of the present invention, those skilled in the art may also make many variations and improvements, which should also be regarded as the protection scope of the present invention.

Claims

1. A rotary transformer decoding device, characterized in that: Including integrator, parallel integrator, phase-locked loop and second-order frequency-locked loop; The input end of the integrator is connected to the output end of the resolver after demodulation, so as to obtain the sine signal and cosine signal output by the resolver demodulation, and perform band-pass filtering on the sine signal and cosine signal to compensate for the amplitude and phase of the sine signal and cosine signal; The input end of the parallel integrator is connected to the output end of the integrator, and is used to perform parallel bandpass filtering on the sine signal and the cosine signal after bandpass filtering to obtain and filter out each harmonic component; The second-order frequency-locked loop is connected to the integrator and the parallel integrator respectively, obtains the center frequency of the sine signal and the cosine signal, and adjusts the center frequency of the integrator; The phase-locked loop is connected to the output of the parallel integrator and is used to obtain the motor rotor angular position and angular frequency according to the sine signal and cosine signal after the parallel bandpass filtering.

2. A rotary transformer decoding device according to claim 1, characterized in that: The integrator comprises a first integrator and a second integrator; The first integrator is used to obtain the sinusoidal signal demodulated and output by the rotary transformer, and to perform bandpass filtering on the sinusoidal signal to compensate for the amplitude and phase of the sinusoidal signal; The second integrator is used to obtain the cosine signal demodulated and output by the rotary transformer, and to perform band-pass filtering on the cosine signal to compensate for the amplitude and phase of the cosine signal.

3. A rotary transformer decoding device according to claim 2, characterized in that: The first integrator and the second integrator are both second-order generalized integrators.

4. A rotary transformer decoding device according to claim 1, characterized in that: The parallel integrator comprises a first parallel integrator and a second parallel integrator; The first parallel integrator is used to perform parallel bandpass filtering on the bandpass filtered sinusoidal signal to obtain and filter out each harmonic component of the sinusoidal signal; The second parallel integrator is used to perform parallel bandpass filtering on the bandpass filtered cosine signal to obtain and filter out the harmonic components of the cosine signal.

5. A rotary transformer decoding device according to claim 4, characterized in that: The first parallel integrator and the second parallel integrator are both parallel second-order generalized integrators.

6. A rotary transformer decoding method, characterized in that: The resolver decoding method is performed using the resolver decoding device according to any one of claims 1 to 5, comprising: Step S1, obtaining a sine signal and a cosine signal outputted by a rotary transformer after demodulation; Step S2, performing bandpass filtering on the sine signal and the cosine signal to obtain a sine signal and a cosine signal with the same fundamental wave amplitude and orthogonal phase; Step S3, obtaining the center frequency of the sine signal and the cosine signal, and adjusting the center frequency of the integrator; Step S4, performing parallel bandpass filtering on the sine signal and cosine signal after bandpass filtering; Step S5, obtaining the motor rotor angular position and angular frequency according to the sine signal and cosine signal after parallel bandpass filtering.

7. The resolver decoding method according to claim 6, characterized in that: In step S3, the method for adjusting the center frequency of the integrator is: The second-order frequency-locked loop obtains an estimated error based on the frequency difference of the sine signal or cosine signal before and after band-pass filtering, and obtains the center frequency of the integrator based on the estimated error and the orthogonal signal of the estimated amount of the sine signal or the orthogonal signal of the estimated amount of the cosine signal, and adjusts the center frequency of the integrator based on the frequency of the sine signal or cosine signal before band-pass filtering.

8. The rotary transformer decoding method according to claim 6, characterized in that: In step S5, the method for obtaining the motor rotor angular position is: The sine signal and cosine signal after parallel bandpass filtering are input into a phase-locked loop, and the input error of the phase-locked loop is obtained; the angular position of the motor rotor is obtained according to the input error of the phase-locked loop and the rotor observation angular position output by the phase-locked loop.

9. The rotary transformer decoding method according to claim 6, characterized in that: In step S5, the method for obtaining the motor rotor angular frequency is: The PI regulator parameters of the phase-locked loop are determined according to the speed regulation range of the motor; the sine signal and the cosine signal after the parallel bandpass filtering are input into the phase-locked loop to obtain the angular frequency of the motor rotor.

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