Design method, system and application of complex vector demodulation system of high-speed rotary transformer

Abstract

The invention discloses a method for designing a complex vector demodulation system of a high-speed rotary transformer. The method comprises a complex vector output construction link of the rotary transformer, an electric rotating speed acquisition link of the rotary transformer, a complex vector amplitude compensation link and a complex vector amplitude normalization link. The rotary transformer output voltage is transmitted to a rotary transformer complex vector output construction link, and complex vector rotary transformer output is constructed; transmitting the complex vector output of the rotary transformer to a rotary transformer electric rotating speed acquisition link to acquire the electric rotating speed of the rotary transformer; performing complex vector amplitude compensation on the electric rotating speed of the rotary transformer, and constructing a compensated excitation conjugate vector of the rotary transformer; and transmitting the output complex vector and the compensated excitation conjugate vector to a complex vector amplitude normalization link, and obtaining an envelope line complex vector through the complex vector amplitude normalization link to obtain output sine and cosine envelope lines of the rotary transformer. According to the method, the angle delay is reduced, the updating frequency is improved, and meanwhile, the error of the 2 omega exc frequency is eliminated.

Description

Technical Field

[0001] The present invention relates to the technical field of high-speed rotary transformers, and in particular to a design method, system and application of a high-speed rotary transformer complex vector demodulation system. Background Art

[0002] In field-oriented control, the resolver, as a position sensor, provides accurate rotor angle and speed information for coordinate transformation, and its accuracy directly affects the efficiency and output power of the motor. In addition, as the demand for high power density in propulsion systems continues to increase, ultra-high-speed / high-speed motors have received widespread attention. However, under high-speed conditions, the current resolver system, especially its demodulation system, is difficult to maintain high angular accuracy. The traditional synchronous sampling demodulation system obtains the envelope by collecting the vertices of the excitation signal, and is subject to the dual challenges of high discrete frequency and low angular delay at high speeds.

[0003] The current resolver-to-digital-conversion (RDC) system mainly includes envelope demodulation, error compensation and angle observer, among which the update frequency and angle delay of the envelope demodulation part directly determine the quantization error and delay error of the output angle of the demodulation system. Compared with the traditional synchronous sampling envelope demodulation algorithm, the envelope demodulation algorithm represented by the filter method can effectively increase the angle update frequency to the sampling frequency. However, due to the introduction of the filter, a large angle delay is also introduced. To this end, scholars proposed a synchronous numerical integration method to further reduce the angle delay while increasing the update frequency to the sampling frequency. However, both of the above methods do not consider the resolver output model at high speed, and introduce a frequency of 2ω into the demodulated angle and speed signals. exc of error. Summary of the invention

[0004] In view of this, the purpose of the present invention is to provide a high-speed rotary transformer complex vector demodulation system design method, system and application, which reduces the angle delay and improves the update frequency while also eliminating the 2ω exc Frequency error.

[0005] The present invention solves the technical problem by adopting the following technical solution:

[0006] A design method for a high-speed rotary transformer complex vector demodulation system includes a rotary transformer complex vector output construction link, a rotary transformer electrical speed acquisition link, a complex vector amplitude compensation link, and a complex vector amplitude normalization link;

[0007] The output voltage of the rotary transformer is passed to the rotary transformer complex vector output construction link to construct a complex vector rotary transformer output; then the constructed rotary transformer complex vector output is passed to the rotary transformer electrical speed acquisition link to obtain the rotary transformer electrical speed; then the acquired rotary transformer electrical speed is passed to the complex vector amplitude compensation link for complex vector amplitude compensation to construct the compensated rotary transformer excitation conjugate vector; finally, the output complex vector constructed by the rotary transformer complex vector output construction link and the compensated excitation conjugate vector constructed by the complex vector amplitude compensation link are passed to the complex vector amplitude normalization link, and finally the envelope complex vector is obtained through the complex vector amplitude normalization link to obtain the output sine and cosine envelope of the rotary transformer.

[0008] Furthermore, the resolver cosine output V c And the sinusoidal output V s As the real and imaginary parts, the normalized resolver complex vector output S out As shown below:

[0009]

[0010] Wherein, V1 is the output voltage amplitude coefficient, and t is the time;

[0011] In the constructed resolver complex vector output S out In the example, the envelope vector S enve The non-ideal excitation vector S is multiplied by the unbalanced amplitude of the real and imaginary parts. exc ', as shown below:

[0012]

[0013] Where, based on the known excitation frequency ω exc , in obtaining the rotating transformer electrical speed ω el After that, it can be compensated in the complex vector envelope demodulation.

[0014] Furthermore, the method for obtaining the electrical speed of the rotary transformer is:

[0015] According to the trigonometric identities, the resolver complex vector output S out The square of the modulus is expressed as:

[0016]

[0017] Among them, due to the excitation frequency ω exc It is known that the electrical speed ω of the rotary transformer can be extracted by the square of the modulus offset el ;

[0018] Module squared |S out | 2 The excitation frequency 2ωexc The components are fixed through the excitation period T exc The numerical integration of is eliminated as shown below:

[0019]

[0020] Among them, M offset and t0 represent the square bias of the modulus and the current time respectively;

[0021] After numerical integration, it needs to be filtered by a low-pass filter with a higher cutoff frequency to suppress the discrete integration error, so as to obtain the offset M after filtering. offset '; At a known excitation frequency ω exc Under this condition, the rotating transformer electrical speed ω el Obtained by the following formula:

[0022]

[0023] in, Indicates the current estimated electrical speed of the resolver.

[0024] Furthermore, the method of complex vector amplitude compensation is as follows:

[0025] According to the principle of complex vector envelope demodulation, a conjugate vector is constructed to realize the electrical speed of the rotary transformer based on the current estimation. The real number of the amplitude imbalance excitation vector; the conjugate vector S exc '*As shown below:

[0026]

[0027] By conjugating the vector S exc '*Multiply, resolver complex vector output S out The non-ideal excitation vector S in exc 'Converted into the square of the modulus of a real number, thereby obtaining the compensated resolver complex vector output S out ', as shown below:

[0028] S' out =S out ×S e ' xc *=|S e ' xc | 2 S enve .

[0029] Furthermore, the complex vector amplitude normalization method is as follows:

[0030] The resolver is not stationary and The minimum value of the square of the modulus of the excitation signal is always greater than zero, as shown below:

[0031]

[0032] Complex vector S out 'The square of the magnitude |S out | 2 can be removed directly without introducing discontinuities with zero denominators; thus, the estimated envelope vector It is obtained by the following formula:

[0033]

[0034] Obtain the electrical speed ω excluding the rotary transformer through the envelope vector el Ideal sinusoidal envelope V' of frequency coupling term senv and the ideal cosine envelope V' cenve , as shown below:

[0035]

[0036] Where R is the real part of the complex vector, and I is the imaginary part of the complex vector;

[0037] Finally, the electrical angle θ of the resolver is obtained based on the obtained envelope through the phase-locked loop angle observer. el .

[0038] A high-speed rotary transformer complex vector demodulation system is used to implement any of the methods described above.

[0039] An application of a high-speed rotary transformer complex vector demodulation system design method, using any of the above methods, deployed in a micro-computing unit including an analog-to-digital conversion module and a pulse width modulation module.

[0040] Beneficial effects of the present invention:

[0041] The present invention provides a design method for a high-speed rotary transformer complex vector demodulation system. The physical voltage of the rotary transformer output in the controller is converted into a mathematical complex vector output through a rotary transformer complex vector output construction link; the real-time electrical speed of the rotary transformer is calculated through a rotary transformer electrical speed acquisition link; the excitation conjugate vector S in the complex vector output constructed in the rotary transformer complex vector output construction link is obtained through a complex vector amplitude compensation link. exc '* vector, the real number of the excitation vector in the complex vector output of the rotary transformer is realized; the excitation signal component in the complex vector output constructed in the complex vector output construction link of the rotary transformer is completely eliminated through the vector amplitude normalization link, and the sine and cosine envelopes of the rotary transformer are obtained, so that the present invention reduces the angle delay and increases the update frequency while also eliminating 2ωexc Frequency error. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It is a schematic diagram of the architecture of the complex vector demodulation system of the rotary transformer of the present invention;

[0043] Figure 2 It is a detailed schematic diagram of the architecture of the complex vector demodulation system of the rotary transformer of the present invention;

[0044] Figure 3 The electric speed acquisition flow chart of the present invention;

[0045] Figure 4 It is a schematic diagram of polar coordinate representation of complex vector signal of rotary transformer of the present invention. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0047] refer to Figure 1 and Figure 2 , the present invention provides a high-speed rotary transformer complex vector demodulation system design method, characterized in that it includes a rotary transformer complex vector output construction link, a rotary transformer electrical speed acquisition link, a complex vector amplitude compensation link and a complex vector amplitude normalization link;

[0048] The output voltage of the rotary transformer is passed to the rotary transformer complex vector output construction link to construct a complex vector rotary transformer output; then the constructed rotary transformer complex vector output is passed to the rotary transformer electrical speed acquisition link to obtain the rotary transformer electrical speed; then the acquired rotary transformer electrical speed is passed to the complex vector amplitude compensation link for complex vector amplitude compensation to construct the compensated rotary transformer excitation conjugate vector; finally, the output complex vector constructed by the rotary transformer complex vector output construction link and the compensated excitation conjugate vector constructed by the complex vector amplitude compensation link are passed to the complex vector amplitude normalization link, and finally the envelope complex vector is obtained through the complex vector amplitude normalization link to obtain the output sine and cosine envelope of the rotary transformer.

[0049] A typical wound rotary transformer consists of a primary and a secondary winding, and is actually a rotating no-load transformer. The primary winding is excited by a high-frequency input voltage signal, and the speed and position information is extracted through the output signals of the secondary sine and cosine windings, which are induced by the excitation signal of the primary winding. The excitation signal V exc Generated by the RDC system:

[0050] V exc =V0 cos(ω exc t)

[0051] Among them, V0 and ω exc represent the excitation amplitude and frequency respectively.

[0052] Under the induction of the excitation voltage, the mutual inductance flux between the primary and secondary windings is shown as follows:

[0053]

[0054] Among them, ms and mc Respectively represent the mutual inductance flux between the primary winding and the secondary sine and cosine windings; ω el is the electrical speed of the rotary transformer; Ψ0 is the mutual inductance flux amplitude.

[0055] The voltage signals of the secondary sine and cosine windings are derived from the flux differentiation, as shown in the following equation:

[0056]

[0057] Among them, V s With V c Represent the output voltage of cosine and sine windings respectively.

[0058] Usually, at medium and low speed operation, the excitation frequency ω exc Much higher than the electric speed ω el ,therefore is close to zero. At this point, the second term of the resolver output can be ignored and simplified to:

[0059] V s '=V1 sin(ω el t)cos(ω exc t)

[0060] V c '=V1 cos(ω el t)cos(ω exc t)

[0061] Furthermore, through the envelope demodulation link of the RDC system, the sinusoidal V containing the current electrical angle information can be obtained. senve ' and cosine Vcenve ' signal, as follows:

[0062]

[0063] However, as the rotating speed of the resolver increases, For example, for a 4-pole resolver, when the mechanical speed increases to 30kr / min, the ratio can reach 0.2 under 10kHz excitation. Therefore, the second term of the resolver output voltage can no longer be ignored, and the amplitude of High-speed output error. And, the electrical speed ω el It is also directly coupled to the high-speed resolver output sinusoidal envelope V senve and cosine envelope V cenve Therefore, it is difficult to obtain accurate angle and speed through the angle observer. The ideal envelope of the demodulation at high speed is sinusoidal V senve and cosine V cenve As shown below:

[0064]

[0065] Therefore, the present invention constructs a complex vector demodulation system based on the high-speed model of the rotary transformer, which effectively utilizes the electrical speed ω in the high-speed output model. el Amplitude coupling term, and eliminates 2ω exc The angular error of the frequency.

[0066] Complex vector model analysis:

[0067] In addition to the physical electrical port model of the resolver (i.e., the resolver input and output), a complex vector resolver model can also be constructed, whose input and output are both complex vector functions. In this model, the input excitation vector S exc and the envelope vector S enve They can be expressed as:

[0068]

[0069] Furthermore, the output S of the complex vector resolver r It can be expressed as:

[0070]

[0071] In the resolver complex vector model, by converting the output S r With the conjugate excitation vector S exc * multiplication, the resolver output vector S can be directly eliminated r The excitation component in the signal can be directly demodulated to obtain the envelope vector S enve, as shown below. Therefore, the complex vector output S r The envelope demodulation process directly removes the limitation of the excitation signal, simplifies the envelope demodulation process, and effectively suppresses the angle delay and quantization error.

[0072]

[0073] The polar coordinate representation of the above complex vector signal is as follows Figure 4 However, the complex excitation signal cannot be directly injected into the actual resolver. r It is also impossible to generate it directly from the physical port of the resolver. Although the Hilbert Transformation (HT) can be used to construct a complex vector, the real-time Hilbert Transformation has a discrete deployment problem. The finite impulse response HT introduces a sampling step delay of half the order to obtain the optimal amplitude response. At the same time, the accuracy of the discrete Fast Fourier Transformation (FFT)-based HT is highly dependent on the periodic integrity of the signal. In addition, the current HT methods are all based on the medium-speed resolver model, while each output voltage in the high-speed resolver model contains sine and cosine excitation signals, which makes the transformed complex vector very complex and difficult to process directly through the angle observer.

[0074] Unlike HT, this patent constructs the vector S by extracting the real and imaginary parts r The output vector S r The real and imaginary parts of are expanded as shown below, and its structure is similar to the high-speed resolver output. The cosine and sine output voltages correspond to the real and imaginary parts of the complex vector, respectively.

[0075]

[0076] As shown in the previous section, the resolver complex vector output can be constructed by extracting the real and imaginary components from the high-speed resolver output voltage. c And the sinusoidal output V s As the real and imaginary parts, the normalized resolver complex vector output S out As shown below:

[0077]

[0078] Wherein, V1 is the output voltage amplitude coefficient, and t is the time;

[0079] With the ideal output vector S r Compared to the complex vector output S of the constructed resolver out In the example, the envelope vector S enveThe non-ideal excitation vector S is multiplied by the unbalanced amplitude of the real and imaginary parts. exc ', as shown below:

[0080]

[0081] Where, based on the known excitation frequency ω exc , in obtaining the rotating transformer electrical speed ω el After that, it can be compensated in the complex vector envelope demodulation.

[0082] The method for obtaining the electrical speed of the complex vector demodulation system is:

[0083] According to the trigonometric identities, the resolver complex vector output S out The square of the modulus is expressed as:

[0084]

[0085] Among them, due to the excitation frequency ω exc It is known that the electrical speed ω of the rotary transformer can be extracted by the square of the modulus offset el ,like Figure 3 As shown. ;

[0086] Module squared |S out | 2 The excitation frequency 2ω exc The components are fixed through the excitation period T exc The numerical integration of is eliminated as shown below:

[0087]

[0088] Among them, M offset and t0 represent the square bias of the modulus and the current time respectively;

[0089] However, the above equation is the integration result in the continuous domain, while the RDC system is implemented in a discrete controller. Therefore, after numerical integration, it is necessary to filter it with a low-pass filter (LPF) with a higher cutoff frequency to suppress the discrete integration error, thereby obtaining the offset M after filtering. offset '; Furthermore, at a known excitation frequency ω exc Under this condition, the rotating transformer electrical speed ω el Obtained by the following formula:

[0090]

[0091] in, Indicates the current estimated electrical speed of the resolver.

[0092] The method of complex vector amplitude compensation is as follows:

[0093] The output vector S constructed out The magnitude imbalance in can be calculated by directly dividing by the non-ideal excitation vector S exc ' to correct. However, since there are zeros in the real and imaginary parts of the denominator, discontinuities may occur. In addition, the complex division method will greatly increase the computational burden of the controller in the RDC system.

[0094] Therefore, according to the principle of complex vector envelope demodulation, a conjugate vector is constructed to realize the electrical speed of the rotary transformer based on the current estimation. The real number of the amplitude imbalance excitation vector; the conjugate vector S exc '*As shown below:

[0095]

[0096] By conjugating the vector S exc '*Multiply, resolver complex vector output S out The non-ideal excitation vector S in exc 'Converted into the square of the modulus of a real number, thereby obtaining the compensated resolver complex vector output S out ', as shown below:

[0097] S' out =S out ×S e ' xc *=|S e ' xc | 2 S enve .

[0098] The complex vector amplitude normalization method is as follows:

[0099] Although the non-ideal excitation vector S exc ' has been converted to the square of the real modulus, but the compensated vector S out The modulus of ' is still not constant and still has 2ω exc Therefore, the square of the modulus needs to be normalized to become a constant coefficient so that it can be input into the angle observer to obtain position information.

[0100] Similar to the filter-based demodulation method, a low-pass filter can be applied to filter out the compensation vector S out '. However, this will introduce a lot of filtering delay, and the delay is different at different speeds. Therefore, the numerical integration method cannot completely eliminate the high-frequency components, and these frequencies are actually related to the electric speed ω el There is frequency coupling.

[0101] However, it is worth noting that as long as the resolver is not stationary and The minimum value of the square of the modulus of the excitation signal is always greater than zero, as shown below:

[0102]

[0103] Therefore, the complex vector S out 'The square of the magnitude |S out | 2 can be removed directly without introducing discontinuities with zero denominators; thus, the estimated envelope vector It can be obtained by the following formula:

[0104]

[0105] The electric speed ω excluding the rotary transformer can be obtained through the envelope vector el Ideal sinusoidal envelope V' of frequency coupling term senv and the ideal cosine envelope V' cenve , as shown below:

[0106]

[0107] Where R is the real part of the complex vector, and I is the imaginary part of the complex vector;

[0108] Finally, the electrical angle θ of the resolver is obtained based on the obtained envelope through the phase-locked loop angle observer. el .

[0109] The present invention provides a design method for a high-speed rotary transformer complex vector demodulation system. The physical voltage of the rotary transformer output in the controller is converted into a mathematical complex vector output through a rotary transformer complex vector output construction link; the real-time electrical speed of the rotary transformer is calculated through a rotary transformer electrical speed acquisition link; the excitation conjugate vector S in the complex vector output constructed in the rotary transformer complex vector output construction link is obtained through a complex vector amplitude compensation link. exc '* vector, the real number of the excitation vector in the complex vector output of the rotary transformer is realized; the excitation signal component in the complex vector output constructed in the complex vector output construction link of the rotary transformer is completely eliminated through the vector amplitude normalization link, and the sine and cosine envelopes of the rotary transformer are obtained, so that the present invention reduces the angle delay and increases the update frequency while also eliminating 2ω exc Frequency error.

[0110] In another embodiment, a high-speed rotary transformer complex vector demodulation system is provided to implement the above method.

[0111] In another embodiment, the above method is applied and deployed in a micro-computing unit including an analog-to-digital conversion module and a pulse width modulation module.

[0112] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A design method for a high-speed rotary transformer complex vector demodulation system, characterized in that: It includes a resolver complex vector output construction link, a resolver electrical speed acquisition link, a complex vector amplitude compensation link, and a complex vector amplitude normalization link; The output voltage of the rotary transformer is passed to the rotary transformer complex vector output construction link to construct a complex vector rotary transformer output; then the constructed rotary transformer complex vector output is passed to the rotary transformer electrical speed acquisition link to obtain the rotary transformer electrical speed; then the acquired rotary transformer electrical speed is passed to the complex vector amplitude compensation link for complex vector amplitude compensation to construct the compensated rotary transformer excitation conjugate vector; finally, the output complex vector constructed by the rotary transformer complex vector output construction link and the compensated excitation conjugate vector constructed by the complex vector amplitude compensation link are passed to the complex vector amplitude normalization link, and finally the envelope complex vector is obtained through the complex vector amplitude normalization link to obtain the output sine and cosine envelope of the rotary transformer.

2. A high-speed rotary transformer complex vector demodulation system design method according to claim 1, characterized in that: The resolver cosine output V c And the sinusoidal output V s As the real and imaginary parts, the normalized resolver complex vector output S out As shown below: Wherein, V1 is the output voltage amplitude coefficient, and t is the time; In the constructed resolver complex vector output S out In the example, the envelope vector S enve The non-ideal excitation vector S is multiplied by the unbalanced amplitude of the real and imaginary parts. exc ', as shown below: Where, based on the known excitation frequency ω exc , in obtaining the rotary transformer electrical speed ω el After that, it can be compensated in the complex vector envelope demodulation.

3. The method for designing a high-speed rotary transformer complex vector demodulation system according to claim 2, characterized in that: The method for obtaining the electrical speed of the rotary transformer is: According to the trigonometric identities, the resolver complex vector output S out The square of the modulus is expressed as: Among them, due to the excitation frequency ω exc It is known that the electrical speed ω of the rotary transformer can be extracted by the square of the modulus offset el ; Module squared |S out | 2 The excitation frequency 2ω exc The components are fixed through the excitation period T exc The numerical integration of is eliminated as shown below: Among them, M offset and t0 represent the square bias of the modulus and the current time respectively; After numerical integration, it needs to be filtered by a low-pass filter with a higher cutoff frequency to suppress the discrete integration error, so as to obtain the offset M after filtering. offset '; At a known excitation frequency ω exc Under this condition, the rotating transformer electrical speed ω el Obtained by the following formula: in, Indicates the current estimated electrical speed of the resolver.

4. The method for designing a high-speed rotary transformer complex vector demodulation system according to claim 3, characterized in that: The method of complex vector amplitude compensation is as follows: According to the principle of complex vector envelope demodulation, a conjugate vector is constructed to realize the electrical speed of the rotary transformer based on the current estimation. The real number of the amplitude imbalance excitation vector; the conjugate vector S exc '*As shown below: By conjugating the vector S exc '* multiplied, the resolver complex vector output S out The non-ideal excitation vector S in exc 'Converted into the square of the modulus of a real number, thereby obtaining the compensated resolver complex vector output S out ', as shown below: S' out =S out ×S e ' xc *=|S e ' xc | 2 S enve 。 5. A high-speed rotary transformer complex vector demodulation system design method according to claim 4, characterized in that: The complex vector amplitude normalization method is as follows: The resolver is not stationary and The minimum value of the square of the modulus of the excitation signal is always greater than zero, as shown below: Complex vector S out 'The square of the magnitude |S out | 2 can be removed directly without introducing discontinuities with zero denominators; thus, the estimated envelope vector It is obtained by the following formula: Obtain the electrical speed ω excluding the rotary transformer through the envelope vector el Ideal sinusoidal envelope V' of frequency coupling term senv and the ideal cosine envelope V' cenve , as shown below: Where R is the real part of the complex vector, and I is the imaginary part of the complex vector; Finally, the electrical angle θ of the resolver is obtained based on the obtained envelope through the phase-locked loop angle observer. el .

6. A high-speed rotary transformer complex vector demodulation system, characterized in that: Used to implement the method according to any one of claims 1 to 5.

7. An application of a high-speed rotary transformer complex vector demodulation system design method, characterized in that: The method according to any one of claims 1 to 5 is applied and deployed in a micro-computing unit including an analog-to-digital conversion module and a pulse width modulation module.

Images