Correlation signal generation method, phase velocity estimation device, and sensorless vector control device

Abstract

To provide a correlation signal generation method for a carrier high-frequency voltage application method using positive-phase and negative-phase high-frequency current extraction, which has the same design freedom as conventional high-frequency voltage application methods and can be realized while suppressing an increase in the calculation load.SOLUTION: In a correlation signal generation method for a carrier high-frequency voltage application method using positive-phase and negative-phase high-frequency current extraction, positive-phase and negative-phase components contained in the high-frequency current (stator current) are extracted, intermediate signals are synthesized using each axial element of the extracted positive-phase and negative-phase high-frequency current, and a positive correlation signal is generated using the synthesized intermediate signals.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a correlation signal generating method, a phase velocity estimating device, and a sensorless vector control device.

[0002] More specifically, the present invention relates to a correlation signal generation method used to estimate the phase (synonymous with position) and speed of a rotor in an AC motor (such as a permanent magnet synchronous motor (PMSM) that is a synchronous motor using a permanent magnet (ferromagnetic material) in the rotor (field), a synchronous reluctance motor, or an induction motor) whose rotor exhibits salient pole characteristics when a high-frequency voltage having a frequency higher than a drive frequency is applied, the correlation signal generation method being a high-frequency voltage application method using positive-phase and negative-phase high-frequency current extraction (the "high-frequency voltage application method using positive-phase and negative-phase high-frequency current extraction" will be described in detail later), a phase speed estimation device that estimates the rotor phase speed using the correlation signal generation method, and a sensorless vector control device equipped with the phase speed estimation device. [Background technology]

[0003] Highly efficient and highly responsive control of AC motors can be achieved by vector control, which requires position information of the motor rotor, and conventionally, position sensors such as encoders have been used to obtain this position information.

[0004] However, this type of position sensor has inherent problems such as reduced reliability, increased volume, and increased cost, so research has been conducted for many years on sensorless vector control methods that do not require position sensors.

[0005] One of the effective sensorless vector control methods is a high-frequency voltage application method in which a high-frequency voltage having a frequency higher than the drive frequency is forcibly applied, and the high-frequency current resulting from the response to the forcible application is processed to obtain an estimated value of the salient pole phase of an AC motor whose rotor exhibits salient pole characteristics in response to the application of a high-frequency voltage having a frequency higher than the drive frequency (see Non-Patent Documents 1 and 2).

[0006] In the high-frequency voltage application method, the rotor phase to be estimated can be determined arbitrarily, but it is common to select either the negative or positive salient pole phase as the rotor phase. There is an electrical phase deviation of ±π / 2 (rad) between the negative and positive salient pole phases, but if one of the phases is determined, the other can be determined automatically.

[0007] Taking the above into consideration, in the following description, unless otherwise specified, the negative salient pole phase of the rotor will be described as the rotor phase.

[0008] The high-frequency voltage application method is characterized by how it extracts a signal component containing phase information contained in the stator current and synthesizes a signal that is correlated with the rotor phase (in this specification and the claims, the "signal that is correlated with the rotor phase" will be referred to as the "correlated signal" as appropriate).

[0009] Typical correlation signals in conventional high-frequency voltage application methods include a positive-phase / negative-phase amplitude correlation signal, an axis element amplitude correlation signal, a high-frequency current correlation signal, and a positive-phase / negative-phase high-frequency current correlation signal (see Non-Patent Documents 2 to 6).

[0010] Here, the positive-phase and negative-phase amplitude correlation signal is a correlation signal synthesized using the extracted positive-phase and negative-phase amplitudes, extracted by filtering the amplitudes of the positive-phase and negative-phase components that make up the high-frequency current generated by applying a high-frequency voltage, and enables the synthesis of correlation signals with a wide variety of characteristics (see Non-Patent Documents 2 to 5).

[0011] The axis element amplitude correlation signal is a correlation signal obtained by extracting the amplitude of each γδ axis element of the high frequency current by filtering and synthesizing the extracted axis element amplitudes (see Non-Patent Documents 2 to 5).

[0012] There is a correspondence between the positive-phase and negative-phase amplitudes and the axis element amplitudes, and it is possible to synthesize a correlation signal with characteristics similar to those of the correlation signal synthesized in the positive-phase and negative-phase amplitude correlation signal in the axis element amplitude correlation signal (see Non-Patent Documents 2 to 5). In addition, when extracting the amplitudes of the positive-phase and negative-phase amplitude correlation signal and the axis element amplitude correlation signal, phase information of the applied high-frequency voltage is required, and this influence appears to change the characteristics of the synthesized positive-phase signal, with some exceptions (see Non-Patent Documents 3 and 4).

[0013] On the other hand, the high frequency current correlation signal is a correlation signal synthesized using each axis element of the high frequency current itself (see Non-Patent Document 2 and Non-Patent Documents 4 to 6). Compared to other signals, this high frequency current correlation signal does not involve extraction of any special signal, so it is possible to reduce the calculation load while not requiring phase information of the applied high frequency voltage, etc. (see Non-Patent Document 2 and Non-Patent Documents 4 to 6).

[0014] However, since noise components are generated in high-frequency current correlation signals during synthesis, it is practical to perform filtering to remove these noise components (see Non-Patent Document 2 and Non-Patent Documents 4 to 6). Also, the characteristics of synthesizable correlation signals appear to have less freedom in design compared to other signals (see Non-Patent Document 2 and Non-Patent Documents 4 to 6).

[0015] The positive-phase and negative-phase high-frequency current correlation signal is an interphase signal synthesized using the axis elements of the positive-phase and negative-phase components that make up the high-frequency current (see Non-Patent Document 1 and Non-Patent Documents 4 to 6). This high-frequency current correlation signal does not necessarily require information such as the phase of the applied high-frequency voltage when extracting the positive-phase and negative-phase components that make up the high-frequency current, so it has the characteristic that this information is less likely to affect its characteristics. Furthermore, although the design freedom regarding the characteristics of the synthesizable correlation signal is superior to that of the high-frequency current correlation signal, it appears to be less (see Non-Patent Document 1 and Non-Patent Documents 4 to 6).

[0016] Here, the main problems with the above-mentioned high-frequency voltage application method have been pointed out as the need to improve the speed of response of phase estimation and the need to reduce audible acoustic noise caused by the applied voltage.

[0017] The limitation of the response speed of phase estimation in the high-frequency voltage injection method is basically due to the large time constant (generally narrow bandwidth) filters used for demodulation. Therefore, there is a demand for a demodulation method that can use a filter with high response speed, or a demodulation method that requires as little as possible of this type of filter.

[0018] On the other hand, with regard to reducing audible acoustic noise in the high-frequency voltage application method, even in the audible range of 4 kHz to 16 kHz, the higher the frequency, the lower the audibility, so there is a demand for proposals for demodulation methods using higher frequencies.

[0019] As an effective method for solving the major problems of the high-frequency voltage application method described above, several methods have been proposed, including applying a high-frequency voltage having a frequency range (a frequency ratio (the frequency ratio between the applied high-frequency voltage and the PWM carrier wave; i.e., "frequency ratio = applied high-frequency voltage / PWM carrier wave frequency") of 1 to 1 / 10 of that of a PWM carrier wave (a carrier wave used in PWM (pulse width modulation)) (in this specification and claims, a "method for applying a high-frequency voltage having a carrier high-frequency range" will be referred to as a "carrier high-frequency voltage application method" as appropriate). (See Non-Patent Documents 3 to 17.)

[0020] Here, the high-frequency current, which is the response of the high-frequency voltage, begins to exhibit a differential discontinuous response as the voltage frequency approaches the PWM carrier wave (see Non-Patent Documents 3 to 17). In conventional high-frequency voltage application methods that apply a high-frequency voltage with a frequency that is approximately 1 / 20 or less of the PWM carrier wave, analysis and processing methods that are premised on a differential continuous response have been widely used (see Non-Patent Documents 1 and 2).

[0021] However, this premise and method can no longer be applied to the carrier high-frequency voltage application method, and analysis and processing methods based on differential processing of the stator current have been used (see Non-Patent Documents 7 to 17). However, this differential processing has the inherent problem of being vulnerable to noise.

[0022] Non-Patent Document 3 proposes a new carrier high-frequency voltage application method in which, while applying a carrier high-frequency voltage, the carrier high-frequency current, which is the response, is processed without differentiation to obtain a phase estimation value.

[0023] This method assumes the use of an inverter (a PWM-compatible power converter). It finds an analytical solution for sampled values ​​of the differentially discontinuous high-frequency current corresponding to the discrete-time application of a high-frequency carrier voltage. Based on this analytical current solution, a demodulation method, i.e., a phase estimation method, is developed. According to this analytical current solution, the difference between when the high-frequency voltage frequency is sufficiently low compared to the carrier frequency and when it is close to the carrier frequency appears as a spatial phase difference between the high-frequency voltage and the high-frequency current, and as the amplitude of the high-frequency current. Taking these differences into consideration, conventional high-frequency voltage application methods (see Non-Patent Documents 1 and 2), which assume that the applied high-frequency voltage frequency is sufficiently low compared to the carrier frequency, can be applied to the high-frequency carrier region (see Non-Patent Documents 3, 5, and 6).

[0024] However, in reality, in addition to these differences, errors appear to occur in the above current analytical solution due to the influence of factors such as the inverter's short circuit prevention period (dead time) and the time delay in the current detection value associated with AD conversion (see Non-Patent Documents 3 and 5).

[0025] Therefore, in the phase estimation method described above, an error appears to occur between the true value and the estimated value of the rotor phase due to the influence of the above-mentioned errors (see Non-Patent Document 5). However, it appears that part of this error can be captured as a change in the spatial phase difference between the amplitude of the current analytical solution and the high-frequency voltage and high-frequency current. By generating a phase deviation equivalent value (correlation signal) that is less affected by these factors, it appears that the influence of the high-frequency voltage error can be sufficiently suppressed (see Non-Patent Documents 3 and 5).

[0026] Non-Patent Documents 18 and 19 propose a method for extracting this phase difference, based on the recognition that the error in the current analytical solution described above that affects phase estimation appears as a phase difference (high-frequency voltage phase error) when the high-frequency voltage command value and its true value are converted into unit vectors, in order to apply the conventional high-frequency voltage injection method to the carrier high-frequency voltage injection method. However, although it is easy to realize a phase correction function using the phase error extracted by this extraction method, an increase in the calculation load is expected.

[0027] Non-Patent Documents 20 and 21 target carrier high-frequency voltage application methods using positive-phase and negative-phase amplitude extraction or axial element amplitude extraction, and by reconstructing the realization of the above-mentioned phase correction function as a correlation signal synthesis method, they are able to minimize the increase in computational load while maintaining the same design freedom in terms of correlation signal characteristics as the previous high-frequency voltage application method.

[0028] Non-Patent Document 6 realizes the above phase correction function while reducing the calculation load by using a positive-phase and negative-phase high-frequency current correlation signal. However, it seems that there is still little design freedom regarding the characteristics of the correlation signal. [Prior art documents] [Non-patent literature]

[0029] [Non-Patent Document 1] Shinji Shinnaka: "Vector Control Technology of Permanent Magnet Synchronous Motors, Volumes 1 and 2 (The Essence of Sensorless Vector Control)", Dempa Shimbunsha (2008-12) [Non-patent document 2] Shinji Shinnaka: "Control of Permanent Magnet Synchronous Motors (Sensorless Vector Control Technology)", University of Tokyo Press (2013-9) [Non-patent document 3] R. Hosooka, S. Shinnaka, N. Nakamura: “New Sensorless Vector Control of PMSM by Discrete-Time Voltage Injection of PWM Carrier Frequency”, IEEJ Trans. IA, vol. 136, No. 11, pp. 837 - 850 (2016 - 11). R. Hosooka, S. Shinnaka, N. Nakamura: “New Sensorless Vector Control of PMSM by Discrete-Time Voltage Injection of PWM Carrier Frequency”, IEEJ Trans. IA, vol. 136, No. 11, pp. 837 - 850 (2016 - 11).

Non-Patent Document 4

Non-Patent Document 5

Non-Patent Document 6

Non-Patent Document 7

[0030] [Non-Patent Document 10] S. Shinnaka, “New Sensorless Vector Control of PMSM by Rotating Voltage Injection of PWM Carrier Frequency”, IEEJ Trans. IA, vol. 134, No. 6, pp. 606-617 (2014-6) Shinji Shinnaka: “Sensorless Vector Control of Permanent Magnet Synchronous Motor by Applying a Circular PWM Carrier High-Frequency Voltage”, Journal of Electrical Engineering D, 134, No. 6, pp. 606-617 (2014-6) [Non-Patent Document 11] YDYoon, SKSul, S.Morimoto, and K.Ide: “High-Bandwidth Sensorless Algorithm for AC Machines Based on Square-Wave-Type Voltage Injection”, IEEE Trans Ind. Appl., Vol. 47, No. 3, pp. 1361-1370 (2011-5 / 6) [Non-Patent Document 12] S.Murakami, T.Shiota, M.Ohta, and K.Ide: “Encoderless Servo Drive With Adequately Designed IPMSM for Pulse-Voltage-Injection-Based Position Detection”, IEEE Trans Ind. Appl., Vol. 48, No. 6, pp. 1922-1930 (2012-11 / 12) [Non-Patent Document 13] S.Kim, and SK Sul: “High Performance Position Sensorless Control Using Rotating Voltage Signal Injection in IPMSM”, EPE 2011, pp. 1-10 (2011-9) [Non-Patent Document 14] S. Kim, JI Ha, and SK Sul: “PWM Switching Frequency Signal Injection Sensorless Method in IPMSM”, IEEE Trans Ind. Appl., Vol. 48, No. 5, pp. 1576-1587 (2012-9 / 10) [Non-Patent Document 15] D. Kaneko, Y. Iwaji, K. Sakamoto, T. Endoh “Initial Rotor Position Estimation of Interior Permanent Magnet Synchronous Motor”, IEEJ Trans. IA, vol. 123, No. 2, pp. 140-148 (2003-2) [Non-Patent Document 16] J.Lara, and A.Chandra: “Performance Study of Switching Frequency Signal Injection Algorithm in PMSMs for EV Propulsion: A Comparison in Stator and Rotor Coordinates”, ISIE 2014, pp. 865-870 (2014-6) [Non-Patent Document 17] D.Kim, YC Kwon, and SK Sul: “Suppression of injection voltage disturbance for High Frequency square-wave injection sensorless drive with regulation of induced High Frequency current ripple”, IPEC-Hiroshima 2014 - ECCE-ASIA, pp. 925-932 (2014-5) [Non-Patent Document 18] Ryu Hosooka: "High-frequency voltage phase error extraction method in carrier high-frequency voltage application method based on positive-phase and negative-phase amplitude correlation for sensorless permanent magnet synchronous motors", 2022 IEEJ Industrial Applications Division Conference 3-10 (2022-8) [Non-Patent Document 19] Akihiro Nakamura, Daiki Kurumatani, Yuta Miyamoto, and Ryu Hosooka: "High-Frequency Error Angle Estimation for Carrier High-Frequency Voltage Application Method Using Elliptical Voltage," 2023 National Convention of the Institute of Electrical Engineers of Japan, 5-095 (2023-9) [Non-Patent Document 20] Ryu Hosooka: "Correlation Signal Synthesis Method for Carrier High-Frequency Voltage Injection Method Using Positive and Negative Phase Amplitude Extraction for Sensorless Permanent Magnet Synchronous Motors", 2023 National Convention of the Institute of Electrical Engineers of Japan, 5-094 (2023-3) [Non-Patent Document 21] Ryu Hosooka: "Correlation Signal Synthesis Method for Carrier High-Frequency Voltage Injection Method Using Shaft Element Amplitude Extraction for Sensorless Permanent Magnet Synchronous Motors", 2023 National Convention of the Institute of Electrical Engineers of Japan, Vol. 5-094 (2023-8) Summary of the Invention [Problem to be solved by the invention]

[0031] The present invention has been made in consideration of the above-mentioned various problems of the conventional technology and demands related to these problems, and an object of the present invention is to provide a correlation signal generation method targeted at a radio frequency voltage application method using positive-phase and negative-phase radio frequency current extraction, which has design freedom equal to or greater than that of conventional radio frequency voltage application methods.

[0032] Another object of the present invention is to provide a phase velocity estimation device using the correlation signal generation method according to the present invention.

[0033] Furthermore, the present invention aims to provide a sensorless vector control device including the phase speed estimation device according to the present invention. [Means for solving the problem]

[0034] In order to achieve the above object, the correlation signal generating method according to the present invention has the following features (1) to (3).

[0035] (1) Four intermediate signals, which have the function of correcting the phase error in the current analytical solution, are synthesized from each axis element of the positive-phase and negative-phase high-frequency currents, and then the correlation signal is synthesized using these intermediate signals.

[0036] (2) The four intermediate signals to be synthesized can be used to synthesize a wide variety of correlation signals depending on the selection of design parameters.

[0037] (3) By selecting specific values ​​as design parameters, the four types of intermediate signals to be synthesized can be used to synthesize positive correlation signals with correlation characteristics equivalent to those of positive-phase inter-phase signals using conventional positive-phase and negative-phase amplitudes and axis element amplitudes. In other words, the design has the same degree of freedom as that of positive-phase inter-phase signals using conventional positive-phase and negative-phase amplitudes and axis element amplitudes.

[0038] The correlation signal generation method according to the present invention, which has the above-mentioned features, is a correlation signal generation method used to estimate a rotor phase speed in an AC motor in which the rotor exhibits salient pole characteristics in response to application of a high frequency voltage having a frequency higher than the driving frequency, and is a correlation signal generation method in a carrier high frequency voltage application method using positive-phase and negative-phase high frequency current extraction, comprising: extracting shaft element amplitudes contained in the high frequency current based on the following equations (25a) and (25b); synthesizing intermediate signals based on the following equations (26a) to (26d) or (27a) to (27d) using the extracted shaft element amplitudes; and using the synthesized intermediate signals,

[0039] p c =f(C 2p ,S 2p ,C 2n ,S 2n ) or

[0040] p c =f(C 2γ ,S 2γ ,S 2δ ,C 2δ ) Based on the positive correlation signal p c The above formula is used to generate the following.

number

[0041] Further, a phase speed estimation device according to the present invention is a correlation signal generation device used to estimate a rotor phase speed in an AC motor in which the rotor exhibits salient pole characteristics in response to application of a high frequency voltage having a frequency higher than a driving frequency, the correlation signal generation device comprising: high frequency voltage application means for generating a discrete high frequency voltage command value; extracting shaft element amplitudes included in the high frequency current based on the following equations (25a) and (25b), synthesizing intermediate signals using the extracted shaft element amplitudes based on the following equations (26a) to (26d) or (27a) to (27d), and using the synthesized intermediate signals,

[0042] p c =f(C 2p ,S 2p ,C 2n ,S 2n ) or

[0043] p c =f(C 2γ ,S 2γ ,S 2δ ,C 2δ ) Based on the positive correlation signal p c and a correlation signal generating means for generating the positive correlation signal p c The rotor phase estimate and speed estimate are generated by using the above equation.

number

[0044] Furthermore, a phase velocity estimating apparatus according to the present invention is the above-described phase velocity estimating apparatus according to the present invention, further comprising phase compensation means for correcting a steady-state phase deviation.

[0045] Moreover, a phase velocity estimation device according to the present invention is the above-described phase velocity estimation device according to the present invention, further comprising a band-pass filter for extracting high frequency components.

[0046] Furthermore, a sensorless vector control device according to the present invention is a sensorless vector control device that controls the drive of an AC motor whose rotor exhibits salient pole characteristics in response to the application of a high frequency voltage that is higher than the drive frequency, and is equipped with the above-described phase speed estimating device according to the present invention. [Effects of the Invention]

[0047] The correlation signal generation method according to the present invention is configured as described above, and therefore has the excellent effect of being able to provide a correlation signal generation method that is intended for a carrier high-frequency voltage application method using positive-phase and negative-phase high-frequency current extraction, and that has the same degree of design freedom as conventional high-frequency voltage application methods, while suppressing an increase in the calculation load.

[0048] Furthermore, the phase velocity estimation device according to the present invention and the sensorless vector control device including the phase velocity estimation device have the excellent effect of being able to be realized while suppressing an increase in the calculation load. [Brief explanation of the drawings]

[0049] [Figure 1] FIG. 1 is an explanatory diagram showing the relationship between three types of coordinate systems and the rotor salient pole phase. [Figure 2] FIG. 2 is a graph showing an example of the characteristics of a positive correlation signal. [Figure 3] FIG. 3 is a block diagram illustrating the configuration of a phase-speed estimator according to an embodiment of the present invention. [Figure 4] FIG. 4 is a block diagram illustrating the configuration of a correlation signal generator in the phase velocity estimation device shown in FIG. [Figure 5] FIG. 5 is a block diagram illustrating the configuration of an extracting filter in the correlation signal generator shown in FIG. [Figure 6]FIG. 6 is a block diagram illustrating the configuration of a sensorless vector control device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0050] Hereinafter, an example of application of the correlation signal generating method, phase speed estimating device, and sensorless vector control device according to the present invention to a permanent magnet synchronous motor will be described in detail with reference to the accompanying drawings.

[0051] (I) Description of a correlation signal generation method according to an example embodiment of the present invention

[0052] FIG. 1 shows an explanatory diagram illustrating the relationship between three types of coordinate systems and the rotor salient pole phases.

[0053] More specifically, Fig. 1 shows an explanatory diagram illustrating the relationship between three coordinate systems—the dq synchronous coordinate system consisting of the d-axis and q-axis, the αβ fixed coordinate system consisting of the α-axis and β-axis, and the γδ quasi-synchronous coordinate system consisting of the γ-axis and δ-axis—and the rotor salient pole phase. The d-axis direction in the diagram is defined as the direction of the rotor's negative salient pole phase.

[0054] In addition, in an AC motor that uses a permanent magnet in the rotor (for example, a permanent magnet synchronous motor), if the effects of nonlinear characteristics such as saturation of the magnetic circuit and inter-axial magnetic flux interference between the d and q axes can be ignored, the d-axis direction is also the north pole direction of the rotor magnet.

[0055] First, as shown in Figure 1, γ In the γδ quasi-synchronous coordinate system rotating at a constant speed, the d-axis of the rotor 10 of the permanent magnet synchronous motor has a phase θ γ It is assumed that the above applies.

[0056] Then, the mathematical model (circuit equation) of the permanent magnet synchronous motor on the γδ quasi-synchronous coordinate system can be written as the following equations (1) to (8).

number

[0057] In the above equations (1) to (8), the 2-row, 1-column vectors ν1, ι1, and φ1 represent the voltage, current, and (linkage) magnetic flux of the stator, respectively. ι ,φ m indicates the components that make up the stator magnetic flux φ1, and φ ι is the stator reaction flux (armature reaction flux) due to the stator current ι1, and φ m is the rotor magnetic flux due to the rotor permanent magnet. I is a 2x2 identity matrix, and J is a 2x2 skew matrix defined by the following equation (9).

number

[0058] Also, ω 2n is the rotor electrical speed and R1 is the resistance of the stator winding. L ι ,L m are the in-phase inductance and mirror-phase inductance of the stator, and have the relationship with the d-axis and q-axis inductances expressed by the following equation (3).

number

[0059] Also, s is the differential operator d / dt.

[0060] When a high frequency voltage is superimposed on the driving voltage, the following equation (11) holds for the voltage, current, and magnetic flux of the stator.

number

[0061] Here, the subscripts f and h in equation (11) mean the driving component and the high frequency component, respectively.

[0062] Next, based on the mathematical model (circuit equation) of the permanent magnet synchronous motor on the γδ quasi-synchronous coordinate system explained above, the discrete-time high-frequency voltage and the discrete-time high-frequency current will be explained.

[0063] First, we will explain the discrete-time high-frequency voltage. When the frequency of the high-frequency voltage and current is sufficiently high compared to the driving voltage and current, the following equation approximately holds:

number

[0064] As shown in the above equations (12a), (12b), (13a), and (13b), the high-frequency magnetic flux φ ιh is the high frequency voltage ν ιh has an integral dynamic relationship with the high frequency current ι ιh is the high frequency magnetic flux φ ιh is in a static relationship to

[0065] Applied high frequency voltage ν 1h The average frequency of ω h Regarding the coordinate system velocity ω γ In the relative ratio, the relationship of the following equation (14) is assumed to hold.

number

[0066] When the above-mentioned equation (14) is satisfied, the equation (13a) is approximated as the following equation (15).

number

[0067] Here, the continuous-time high-frequency voltage ν 1h is applied through a power converter modeled as a zero-order holder.

[0068] Also,

[0069] Time t=kT s ~(k+1)T s Continuous-time high-frequency voltage ν 1h The discrete-time high-frequency voltage corresponding to 1h,k It is expressed as: Discrete-time high-frequency voltage ν 1h,k As the high frequency period T h , average speed ω h Consider a constant elliptical high-frequency voltage with the following elliptical coefficient K, which rotates spatially with

number

[0070] Here, the footnote k stands for t=kT s This means the sampling time at θ h0 is the initial phase of the applied high frequency voltage, and in this specification and claims, unless otherwise specified, θ h0 = 0. The high frequency period T h For simplicity, we use the discrete time period T s and a positive integer N h The selection shall be made so as to hold the following relationship using ≥ 2:

number

[0071] In addition, N h When K is set to 2, the voltage waveform is linear regardless of the elliptic coefficient K.

[0072] Next, we will explain the discrete-time high-frequency current response. 1h,k The discrete-time high-frequency current ι for the application of 1h,k When the elliptic coefficient K is constant, is given by the following equation:

number

[0073] Next, extraction of positive and negative phase components of a discrete-time high-frequency current and phase estimation will be described, but first amplitude extraction and synthesis of correlation signals will be described.

[0074] First, the extraction of positive and negative phase components will be explained. The high frequency current ι is calculated based on the following equation. 1h,k The positive and negative sequence components contained in the signal are extracted.

number

[0075] In the above formula,

number

number

[0076] Next, we will explain the synthesis of intermediate signals. c As a preparation for synthesizing the positive and negative sequence high frequency currents extracted based on Eqs. (25a) and (25b),

number

number

[0077] In equations (26a) to (26d), K pc =K ps =K nc =K ns =K and selected positive-phase and negative-phase intermediate signal C 2p ,S 2p ,C 2n ,S 2n and positive and negative amplitude c p ,s p ,c n ,s n are proportional to each other as shown in the following equation, and by taking this difference into consideration, it becomes possible to apply the conventional correlation signal synthesis method using positive-phase and negative-phase amplitudes to the carrier high-frequency voltage application method.

number

[0078] In addition, in equations (27a) to (27d), K γc =K γs =K δc =K and the selected axial element type intermediate signal C 2γ ,S 2γ ,S 2δ ,C 2δ and the axial element amplitude c γ ,s γ ,s δ ,c δ are proportional to each other as shown in the following equation, and by taking this difference into consideration, it becomes possible to apply the conventional correlation signal synthesis method using the axial element amplitude to the carrier high frequency voltage application method.

number

[0079] Next, the synthesis of the positive correlation signal will be explained. The positive-phase and negative-phase intermediate signal C 2p ,S 2p ,C 2n ,S 2n or shaft element type intermediate signal C2γ ,S 2γ ,S 2δ ,C 2δ Using the positive correlation signal p c A method for synthesizing the above will be described.

[0080] That is, a wide variety of correlation signal synthesis methods based on the following equation (30) or (31) are possible, similar to the conventional positive correlation signal synthesis method using positive-phase and negative-phase amplitudes and axis element amplitudes.

[0081] p c =f(C 2p ,S 2p ,C 2n ,S 2n ) (30)

[0082] p c =f(C 2γ ,S 2γ ,S 2δ ,C 2δ ) (31)

[0083] In this specification and claims, a positive correlation signal given by the following equation is shown as an example of the correlation signal synthesis method based on equation (30).

number

[0084] Here, atan2(·) means four-quadrant arctangent processing. c is an arbitrary design parameter left to the designer. The positive correlation signal synthesized based on the above equation (32) is pc ,K ps ,K nc ,K ns This allows for a very high degree of freedom in design regarding the positive phase correlation characteristics and calculation load, including the selection of

[0085] In Fig. 2, the elliptic coefficient K = 0.5, the design parameter K c2 shows an example of the characteristics of the positive correlation signal based on equation (32) under the condition of =K. As can be seen from Fig. 2, the phase characteristics of this positive correlation signal vary depending on the design parameters when the elliptic coefficient K = 0.5.

number

[0086] Next, the generalized integral PLL method will be explained. c is processed based on the generalized integral PLL method, and the rotor phase estimate seen from the α axis is

number

number

number

[0087] Here, Δθ on the right side of equation (33a) s is a compensation signal for the steady phase deviation caused by inter-axis magnetic flux interference, high frequency residual disturbance, etc. Also, the rotor speed estimate

number

[0088] In addition, equation (33c) shows two examples: direct use and use of a low-pass filter.

[0089] (II) Description of a phase velocity estimation device according to an embodiment of the present invention

[0090] FIG. 3 is a block diagram illustrating the configuration of a phase-speed estimator according to an embodiment of the present invention.

[0091] In FIG. 3 and FIGS. 4 to 6 described later, vector signals are shown by a single thick signal line to improve visibility.

[0092] That is, FIG. 3 shows a phase speed estimator that is responsible for generating discrete-time high-frequency voltage commands and processing discrete-time high-frequency currents to generate rotor phase and speed estimates.

[0093] The phase-speed estimator 100 shown in FIG. 3 includes a high-frequency voltage commander (HFVC) 102 as high-frequency voltage application means for generating discrete high-frequency voltage command values ​​based on equations (16a) to (16c), and a correlation signal generator as correlation signal generation means for extracting positive and negative sequence components contained in a high-frequency current (stator current) based on equations (25a) and (25b), synthesizing intermediate signals based on equations (26a) to (26d) or equations (27a) to (27d) using the extracted positive and negative sequence high-frequency currents, and generating a positive correlation signal based on equation (30) or equation (31) using the synthesized intermediate signals. The phase synchronizing means is configured to generate an estimated value of the rotor phase and the estimated value of the speed of the rotor as viewed from the α-axis of the rotor based on equations (33a), (33b), (33c), and (33d).

[0094] Reference numeral 108 denotes a band-pass filter that extracts high-frequency components, but this is not necessarily required in the phase velocity estimation apparatus 100, depending on the design of an extracting filter (see FIG. 4) that serves as amplitude extraction means constituting the correlation signal generator 104. Taking this into consideration, it is indicated by a dashed line block in FIG. 3.

[0095] Further, reference numeral 110 denotes a phase compensator, which is a phase compensation means. This phase compensator 110 outputs a phase correction signal K θ Δθ s However, since it is not necessarily required for implementing the phase velocity estimation device 100 according to the present invention, it is indicated by a dashed block like the band-pass filter 108.

[0096] FIG. 4 shows a block diagram of a correlation signal generator in the phase velocity estimation device shown in FIG.

[0097] FIG. 5 is a block diagram illustrating the configuration of an extracting filter in the correlation signal generator shown in FIG.

[0098] The correlation signal generator 104 is configured to include an extracting filter 112 serving as positive-phase / negative-phase component extracting means for extracting positive-phase and negative-phase components contained in the high-frequency current (stator current) based on equations (25a) and (25b), and a correlation signal synthesizer 114 serving as positive correlation signal synthesizing means for synthesizing intermediate signals based on equations (26a) through (26d) or equations (27a) through (27d) and synthesizing a positive correlation signal based on equation (30) or equation (31).

[0099] In the above configuration, phase speed estimation device 100 receives as input the stator current on the γδ quasi-synchronous coordinate system, which is the output signal of a vector rotator (see vector rotator 212 shown in FIG. 6 ), and outputs a rotor phase estimate, a speed estimate, and a discrete high-frequency voltage command value.

[0100] More specifically, the high-frequency voltage command generator 102 generates a discrete high-frequency voltage command value based on equations (16a) to (16c), and outputs it to the outside of the phase velocity estimation device 100.

[0101] Then, the amplitude extractor 112 of the correlation signal generator 104 extracts the discrete-time high-frequency current l 1h,k to each axis element of the positive and negative sequence components

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[0102] Each axis element of the positive and negative phase high frequency current extracted by the extraction filter 112

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[0103] The correlation signal combiner 114 combines the intermediate signals based on equations (26a) to (26d) or equations (27a) to (27d) and generates a positive correlation signal p based on equation (30) or equation (31). c The positive correlation signal p c is output to the phase synchronizer 106.

[0104] The phase synchronizer 106 generates a positive correlation signal p c (33a), (33b), (33c), and (33d) are executed using the above equations to obtain the estimated rotor phase value seen from the α-axis of the rotor of the permanent magnet synchronous motor.

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[0105] (III) Description of a sensorless vector control device according to an embodiment of the present invention

[0106] FIG. 6 is a block diagram illustrating the configuration of a sensorless vector control device according to an embodiment of the present invention.

[0107] The sensorless vector control device 200 according to this embodiment of the present invention includes the phase speed estimation device 100 according to the present invention described above, and controls the driving of a permanent magnet synchronous motor 300 .

[0108] In FIG. 6, a block S indicated by reference numeral 202 T is a three-phase to two-phase converter, and S indicated by reference numeral 204 is a two-phase to three-phase converter.

[0109] In Figure 6, the stator voltage and stator current are expressed with the subscripts r (γδ quasi-synchronous coordinate system), s (αβ fixed coordinate system), and t (uvw coordinate system) to clearly indicate the coordinate systems in which these signals are defined.

[0110] The sensorless vector control device 200 includes the phase speed estimation device 100 described above, and the application of the stator voltage and the detection and control of the stator current are performed in discrete time, with these being synchronized.

[0111] In the sensorless vector control device 200, a block F indicated by reference numeral 206 in the current feedback bs (z -1 ) is a high-frequency component removal filter (a digital filter for removing high-frequency components) that removes high-frequency components from the stator current, but it is sometimes not used. Taking this into consideration, it is shown by a dashed block in Figure 6.

[0112] In addition, the digital filter F bs (z -1 Generally, a band-stop filter is used as the high-frequency current filter, but if the frequency of the high-frequency current is particularly high, a wide-bandwidth low-pass filter may be used.

[0113] More specifically, the sensorless vector control device 200 is configured to include a power converter (inverter) 208, a discrete-time current detector 210, a three-phase to two-phase converter 202, a two-phase to three-phase converter 204, an inverse vector rotator 212, a vector rotator 214, a current controller 216, a command converter 218, a speed controller 220, a high-frequency component removal filter 206, the phase speed estimator 100 according to the present invention described above, a coefficient multiplier 222, and a cosine / sine signal generator 224.

[0114] In the sensorless vector control device 200, the three-phase stator currents detected by the discrete-time current detector 210 are converted by the three-phase to two-phase converter 202 into two-phase currents on an αβ fixed coordinate system, and then converted by the inverse vector rotator 212 into two-phase currents on a γδ quasi-synchronous coordinate system that aims for phase synchronization with the rotor phase (identical to the phase in the dq synchronous coordinate system) with zero phase deviation.

[0115] The two-phase current converted by the three-phase to two-phase converter 202 has high-frequency components contained in the stator current removed by the high-frequency component removal filter 206, and the two-phase current from which the high-frequency components have been removed is output to the current controller 216.

[0116] The current controller 216 generates two-phase drive voltage command values ​​on the γδ quasi-synchronous coordinate system so that the two-phase drive currents on the γδ quasi-synchronous coordinate system follow the current command values ​​of each phase.

[0117] Here, in the sensorless vector control device 200, the discrete high-frequency voltage command value generated by the high-frequency voltage command device 102 of the phase speed estimation device 100 is superimposed on the two-phase driving voltage command value, and the superimposed and synthesized two-phase voltage command value is output to the vector rotator 214.

[0118] The vector rotator 214 converts the superimposed voltage command value on the γδ quasi-synchronous coordinate system into a two-phase voltage command value on the αβ fixed coordinate system, and outputs it to the two-phase to three-phase converter 204 .

[0119] Then, the two-phase to three-phase converter 204 converts the two-phase voltage command values ​​into three-phase voltage command values, and outputs them to the power converter 208 as final voltage command values.

[0120] The power converter 208 generates a voltage according to the final voltage command value, and applies this voltage to the permanent magnet synchronous motor 300 to control the driving of the permanent magnet synchronous motor 300 .

[0121] As described above, the phase speed estimation device 100 receives as input the stator current in the γδ quasi-synchronous coordinate system, which is the output signal of the vector rotator 212, and outputs a rotor phase estimate, a rotor speed estimate, and a discrete high-frequency voltage command value.

[0122] The rotor phase estimate output from the phase speed estimation device 100 is converted into a cosine-sine signal in a cosine-sine signal generator 224, and then output to an inverse vector rotator 212 and a vector rotator 214 that determine the γδ quasi-synchronous coordinate system. This means that the rotor phase estimate is set to the phase of the γδ quasi-synchronous coordinate system (equivalent to the phase of the γ axis).

[0123] Moreover, two-phase current command values ​​on the γδ quasi-synchronous coordinate system are obtained by converting the torque command value through a command converter 218. The speed controller 220 converts the rotor speed estimate, which is one of the output signals from the phase speed estimator 100, into a constant value, the number of pole pairs N p is multiplied by the inverse of the coefficient multiplier 22 and converted into an estimated machine speed value, and then sent.

[0124] 6 shows an example in which a speed control system is configured, and therefore a torque command value is obtained as the output of speed controller 220. Note that if the control purpose is torque control and no speed control system is configured, speed controller 220 is not necessary. In this case, the torque command value is applied directly from the outside.

[0125] (IV) Effects of the correlation signal generating method, phase velocity estimating device, and sensorless vector control device according to an embodiment of the present invention

[0126] The above explanation has been given of a correlation signal generation method for the carrier high-frequency voltage injection method using positive-phase and negative-phase high-frequency current extraction. This correlation signal generation method synthesizes four types of intermediate signals using each axis element of the positive-phase and negative-phase high-frequency current as a preliminary step to synthesizing the correlation signal, and then uses these to synthesize the positive-phase-to-positive phase signal. When synthesizing the intermediate signals, it is possible to synthesize positive correlation signals with a wide variety of characteristics by selecting arbitrary parameters, and it is also possible to synthesize positive correlation signals with characteristics equivalent to those of the conventional high-frequency current amplitude correlation method in the carrier high-frequency voltage injection method.

[0127] (V) Other embodiments

[0128] It should be noted that the above-described embodiment is merely an example, and the present invention can be embodied in various other forms. In other words, the present invention is not limited to the above-described embodiment, and various omissions, substitutions, or modifications can be made as appropriate within the scope of the gist of the present invention.

[0129] That is, in the above, a detailed description has been given of a case where the present invention is applied to a permanent magnet synchronous motor as an example of an embodiment of the correlation signal generating method, phase speed estimating device, and sensorless vector control device according to the present invention.

[0130] However, the configurations of the correlation signal generating method, the phase velocity estimation device, and the sensorless vector control device according to the present invention are not limited to the embodiments described above, and various omissions, substitutions, or modifications can be made as appropriate within the scope of the gist of the present invention.

[0131] Furthermore, in the above, in order to facilitate understanding of the present invention, a permanent magnet synchronous motor has been taken as an example of an AC motor, and the correlation signal generating method, phase speed estimating device, and sensorless vector control device related thereto have been described in detail. However, the correlation signal generating method, phase speed estimating device, and sensorless vector control device according to the present invention are not limited to applications to permanent magnet synchronous motors, but can be applied to any AC motor (in addition to permanent magnet synchronous motors, there are also synchronous reluctance motors, induction motors, and the like) as long as the rotor exhibits salient pole characteristics when a high-frequency voltage having a frequency higher than the drive frequency is applied. [Industrial Applicability]

[0132] The present invention can be used to control an AC motor whose rotor exhibits salient pole characteristics when a high frequency voltage higher than the driving frequency is applied. [Explanation of symbols]

[0133] 10 Rotor 100 Phase-speed estimator 102 High-Frequency Voltage Commander (HFVC) (High-Frequency Voltage Application Means) 104 Correlation signal generator (correlation signal generating means) 106 Phase synchronizer (estimated value generation means) 108 Band-pass filter 110 Phase compensator (phase compensation means) 112 Extracting Filter (positive phase negative phase high frequency current extraction means) 114 Correlation signal synthesizer (correlation signal synthesizer) 200 Sensorless Vector Control Device 202 Three-phase to two-phase converter 204 2-phase to 3-phase converter 206 High frequency component removal filter (digital filter for removing high frequency components) 208 Power Converter (Inverter) 210 Discrete-Time Current Detector 212 Inverse Vector Rotator 214 Vector Rotator 216 Current controller 218 Command converter 220 Speed ​​controller 222 Coefficient Multiplier 224 Cosine Sine Signal Generator 300 Permanent magnet synchronous motor (SM)

Claims

1. 1. A correlation signal generation method used to estimate a rotor phase speed in an AC motor in which a rotor exhibits salient pole characteristics when a high-frequency voltage having a frequency higher than a driving frequency is applied, comprising: In a correlation signal generation method in a high frequency voltage application method using positive and negative phase high frequency current extraction, Extracting positive and negative phase components contained in the high frequency current based on the following equations (25a) and (25b): Using the extracted axial elements of the positive-phase and negative-phase high-frequency currents, an intermediate signal is synthesized based on the following equations (26a) to (26d) or (27a) to (27d): Using the synthesized intermediate signal, p ｃ =f(C ２ｐ ,S ２ｐ ,C ２ｎ ,S ２ｎ ) or p ｃ =f(C ２γ ,S ２γ ,S ２δ ,C ２δ ) Based on the positive correlation signal p ｃ Generate A correlation signal generation method comprising: [0000]

2. A phase speed estimation device used to estimate a rotor phase speed in an AC motor whose rotor exhibits salient pole characteristics when a high-frequency voltage having a frequency higher than a driving frequency is applied, a high-frequency voltage application means for generating a high-frequency voltage command value; The positive and negative phase components included in the high frequency current are extracted based on the following formulas (25a) and (25b), and intermediate signals are synthesized based on the following formulas (26a) to (26d) or (27a) to (27d) using the extracted axial elements of the positive and negative phase high frequency currents. The synthesized intermediate signals are then used to: p ｃ =f(C ２ｐ ,S ２ｐ ,C ２ｎ ,S ２ｎ ) or p ｃ =f(C ２γ ,S ２γ ,S ２δ ,C ２δ ) Based on the positive correlation signal p ｃ a correlation signal generating means for generating a correlation signal; The positive correlation signal p generated by the correlation signal generating means ｃ an estimate generating means for generating rotor phase estimates and speed estimates using A phase velocity estimation device comprising: [0000]

3. 3. The phase velocity estimation device according to claim 2, further comprising: a phase compensation means for correcting a steady-state phase deviation; A phase velocity estimation device comprising:

4. The phase velocity estimation device according to claim 2 or 3, further comprising: A bandpass filter to extract high frequency components A phase velocity estimation device comprising:

5. A sensorless vector control device controls the drive of an AC motor whose rotor exhibits salient pole characteristics when a high-frequency voltage having a frequency higher than a drive frequency is applied, A phase velocity estimation device according to claim 2 is provided. A sensorless vector control device characterized by:

6. A sensorless vector control device controls the drive of an AC motor whose rotor exhibits salient pole characteristics when a high-frequency voltage having a frequency higher than a drive frequency is applied, A phase velocity estimation device according to claim 3 is provided. A sensorless vector control device characterized by:

7. A sensorless vector control device controls the drive of an AC motor whose rotor exhibits salient pole characteristics when a high-frequency voltage having a frequency higher than a drive frequency is applied, A phase velocity estimation device according to claim 4 is provided. A sensorless vector control device characterized by:

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