Method for estimating rotating speed and position of rotor of phase-locked loop, phase-locked loop and synchronous motor

Abstract

The invention relates to the technical field of power electronics, in particular to a phase-locked loop rotor speed and position estimation method, which comprises the following steps: acquiring an extended back electromotive force estimation value and a current frequency estimation value of a motor; preprocessing the extended back electromotive force estimation value to obtain an input signal of the SOGI module; based on the current frequency estimation value, performing harmonic interference processing on the input signal through an SOGI module to obtain a target fundamental component; dynamically adjusting the proportional gain and integral gain of a PI control module based on the target fundamental component and the current frequency estimation value to obtain a target frequency estimation value; and according to the target frequency estimation value, a target rotating speed estimation value and a target position estimation value of the rotor are obtained, and the target frequency estimation value is used as a next frequency estimation value of the current frequency estimation value and is fed back to the SOGI module and the PI control module. The method improves the accuracy and precision of the estimated values of the rotating speed and the position of the rotor, and enhances the dynamic response performance.

Description

Technical Field

[0001] The present invention relates to the field of power electronics technology, and in particular, to a method for estimating the rotational speed and position of a phase-locked loop rotor, a phase-locked loop, and a synchronous motor. Background Art

[0002] In power electronic systems (such as motor drives, inverters), the input signal usually contains harmonic interference signals. These harmonic interference signals reduce the accuracy of the estimated values of the rotational speed and position of the phase-locked loop rotor, and further significantly affect the frequency estimation accuracy of the phase-locked loop (PLL), resulting in oscillations or errors in the output signal of the phase-locked loop. Nowadays, a harmonic suppression module is usually designed in the phase-locked loop to solve the problem of low frequency estimation accuracy of the phase-locked loop.

[0003] However, the existing harmonic suppression modules are usually fixed-parameter filters, such as filters that only deal with a certain fixed harmonic frequency. The existing harmonic suppression modules cannot dynamically adapt to the change of harmonic frequency. Especially when the fundamental frequency fluctuates, the performance of the existing harmonic suppression modules is worse. Moreover, the proportional gain and integral gain of the PI (Proportional-Integral) controller in the existing phase-locked loop are both fixed values and it is difficult to adapt to dynamic working conditions. Among them, the dynamic working conditions are working conditions such as frequency mutation and load fluctuation. This results in a decrease in the accuracy of the estimated values of the rotational speed and position of the rotor by the PI controller of the existing phase-locked loop, and also reflects the poor dynamic response performance of the phase-locked loop. Therefore, the existing phase-locked loop has problems of poor accuracy of the estimated values of the rotational speed and position of the rotor and poor dynamic response performance. Summary of the Invention

[0004] Embodiments of the present application provide a method for estimating the rotational speed and position of a phase-locked loop rotor, a phase-locked loop, and a synchronous motor, which solve the technical problems that the existing phase-locked loop has poor accuracy of the estimated values of the rotational speed and position of the rotor and poor dynamic response performance, realize the filtering of harmonic interference of the input signal, improve the accuracy and precision of the estimated values of the rotational speed and position of the rotor by the phase-locked loop, and further eliminate the steady-state error, improve the accuracy and precision of the output signal of the phase-locked loop, and can also dynamically adapt to the estimated values of the rotational speed and position of the rotor, enhance the dynamic response performance of the phase-locked loop, and ensure long-term tracking accuracy and other technical effects.

[0005] In a first aspect, an embodiment of the present invention provides a method for estimating the rotational speed and position of a phase-locked loop rotor, including:

[0006] Obtain an estimated value of the extended back electromotive force of the motor and a current estimated frequency value;

[0007] Preprocess the estimated value of the extended back electromotive force to obtain an input signal of a second-order generalized integrator module (SOGI module);

[0008] Based on the current frequency estimation value, the input signal is processed for harmonic interference by the SOGI module to obtain a target fundamental component, where the harmonic interference processing is a process of suppressing the harmonics in the input signal in real time through the current center frequency estimation value;

[0009] Based on the target fundamental component and the current frequency estimation value, the proportional gain and integral gain of the PI control module are dynamically adjusted by the PI control module to obtain a target frequency estimation value;

[0010] According to the target frequency estimation value, a target rotational speed estimation value and a target position estimation value of the rotor are obtained, and the target frequency estimation value is used as the next frequency estimation value of the current frequency estimation value and fed back to the SOGI module and the PI control module to realize dynamic adjustment of the frequency estimation value of the phase-locked loop.

[0011] Optionally, the processing of the input signal for harmonic interference by the SOGI module based on the current frequency estimation value to obtain a target fundamental component includes:

[0012] A target harmonic component is obtained according to the current frequency estimation value and the current fundamental component of the SOGI module;

[0013] The target fundamental component is obtained according to the input signal and the target harmonic component.

[0014] Optionally, the obtaining of the target harmonic component according to the current frequency estimation value and the current fundamental component of the SOGI module includes:

[0015] The current frequency estimation value is multiplied by a set multiple to obtain an extended frequency estimation value, where the set multiple is an even multiple;

[0016] A first harmonic component is obtained according to the extended frequency estimation value and the current harmonic component of the SOGI module;

[0017] A second harmonic component is obtained according to the current fundamental component and the first harmonic component;

[0018] The target harmonic component is obtained according to the second harmonic component and the extended frequency estimation value.

[0019] Optionally, the processing of the input signal for harmonic interference by the SOGI module based on the current frequency estimation value to obtain a target fundamental component further includes:

[0020] Based on the input signal, the current frequency estimate, and the target fundamental component, the transfer function of the SOGI module is obtained, where the transfer function of the SOGI module is:

[0021]

[0022] where in-SOGI represents the input signal, out-SOGI represents the target fundamental component, s is the complex frequency variable, representing the complex frequency in the Laplace transform: s = σ + jω, K is the gain coefficient of the SOGI module, and ω r is the extended frequency estimate obtained by multiplying the current frequency estimate by a set multiple.

[0023] Optionally, based on the target fundamental component and the current frequency estimate, the proportional gain and integral gain of the PI control module are dynamically adjusted through the PI control module to obtain the target frequency estimate, including:

[0024] Based on the current frequency estimate, the reference frequency estimate of the PI controller of the PI control module, the proportional base gain, the integral base gain, the proportional adaptive adjustment coefficient, and the integral adaptive adjustment coefficient, the proportional gain and the integral gain are obtained;

[0025] Based on the proportional gain and the target fundamental component, a first frequency value is obtained, and based on the integral gain and the target fundamental component, a second frequency value is obtained;

[0026] Based on the first frequency value and the second frequency value, the target frequency estimate is obtained.

[0027] Optionally, based on the target fundamental component and the current frequency estimate, the proportional gain and integral gain of the PI control module are dynamically adjusted through the PI control module to obtain the target frequency estimate, including:

[0028] The PI controller of the PI control module obtains the proportional gain and the integral gain based on the module inference model and the current frequency estimate, where the module inference model includes the Mamdani model and the Sugeno model;

[0029] Based on the integral gain and the target fundamental component, a first frequency value is obtained, and based on the proportional gain and the target fundamental component, a second frequency value is obtained;

[0030] Based on the first frequency value and the second frequency value, the target frequency estimate is obtained.

[0031] Optionally, preprocessing the estimated extended back electromotive force to obtain an input signal for a second-order generalized integrator module (SOGI module), including:

[0032] Normalize the estimated extended back electromotive force to obtain a processed estimated extended back electromotive force, where the processed estimated extended back electromotive force includes: a processed estimated extended back electromotive force on the α-axis and a processed estimated extended back electromotive force on the β-axis;

[0033] Obtain an estimated current position of the rotor according to the estimated current frequency;

[0034] Obtain a unit extended back electromotive force vector on the α-axis according to the processed estimated extended back electromotive force on the α-axis and the estimated current position, and obtain a unit extended back electromotive force vector on the β-axis according to the processed estimated extended back electromotive force on the β-axis and the estimated current position;

[0035] Obtain the input signal according to the unit extended back electromotive force vector on the α-axis and the unit extended back electromotive force vector on the β-axis.

[0036] Based on the same inventive concept, in a second aspect, the present invention further provides a phase-locked loop for applying the method for estimating the rotor speed and position of the phase-locked loop as described in the first aspect. The phase-locked loop includes:

[0037] An SOGI module for, after obtaining the estimated extended back electromotive force and the estimated current frequency of the motor, and preprocessing the estimated extended back electromotive force to obtain an input signal for the second-order generalized integrator module (SOGI module), performing harmonic interference processing on the input signal based on the estimated current frequency to obtain a target fundamental component, where the harmonic interference processing is a process of suppressing harmonics in the input signal in real time through the estimated current center frequency;

[0038] A PI control module for dynamically adjusting the proportional gain and integral gain of the PI control module based on the target fundamental component and the estimated current frequency to obtain an estimated target frequency, so as to obtain an estimated target speed and an estimated target position of the rotor through the estimated target frequency, and using the estimated target frequency as the next estimated frequency of the estimated current frequency and feeding it back to the SOGI module and the PI control module to achieve dynamic adjustment of the frequency estimation value of the phase-locked loop.

[0039] Optionally, the SOGI module includes: a first subtractor, a second subtractor, a first integrator, a second integrator, a first multiplier, a second multiplier, and a target multiplier;

[0040] The target multiplier is used to multiply the current frequency estimate by a set multiple to obtain an extended frequency estimate, where the set multiple is an even multiple;

[0041] The first subtractor is used to output a fundamental component according to the received input signal and harmonic component;

[0042] The first integrator is used to receive the harmonic component and perform integration processing on the harmonic component to output the integrated harmonic component;

[0043] The first multiplier is used to obtain a first harmonic component according to the received integrated harmonic component and the extended frequency estimate;

[0044] The second subtractor is used to obtain a second harmonic component according to the received fundamental component and the first harmonic component;

[0045] The second multiplier is used to obtain a processed harmonic component according to the received second harmonic component and the extended frequency estimate;

[0046] The second integrator is used to perform integration processing on the received processed harmonic component to obtain the harmonic component.

[0047] Based on the same inventive concept, in a third aspect, the present invention provides a synchronous motor, including: the phase-locked loop as described in the second aspect.

[0048] One or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages:

[0049] In the embodiments of the present invention, after obtaining the extended back electromotive force estimate and the current frequency estimate of the motor, the extended back electromotive force estimate is first preprocessed to obtain the input signal of the second-order generalized integrator module (SOGI module). Then, based on the current frequency estimate, the input signal is subjected to harmonic interference processing through the SOGI module to obtain the target fundamental component. Among them, the harmonic interference processing is a process of suppressing the harmonics in the input signal in real time through the current center frequency estimate. Here, by using a single SOGI module, the harmonics generated due to the nonlinearity of the inverter are eliminated, ensuring the accuracy and precision of the target fundamental component, thereby improving the accuracy and stability of the rotor speed and position. Moreover, by using a single SOGI filter, the burden on hardware resources and computing amount in the existing multi-filter scheme is greatly reduced.

[0050] Next, based on the target fundamental wave component and the current frequency estimation value, the proportional gain and integral gain of the PI control module are dynamically adjusted through the PI control module to obtain the target frequency estimation value. Here, based on the target fundamental wave component and the current frequency estimation value, the PI control module is dynamically and adaptively adjusted, and the proportional gain and integral gain of the PI control module are dynamically optimized. In this way, the accuracy and precision of the target frequency estimation value are further ensured, thereby enhancing the accuracy and stability of the rotor speed and position, and optimizing the overall control performance. Then, according to the target frequency estimation value, the target rotor speed estimation value and the target position estimation value of the rotor are obtained. And the target frequency estimation value is used as the next frequency estimation value of the current frequency estimation value and fed back to the SOGI module and the PI control module to dynamically adjust the frequency estimation value of the phase-locked loop. In this way, based on the target frequency estimation value with high accuracy and high precision, the rotor speed and position with high accuracy and high precision can be obtained to efficiently master the rotor and position of the rotor, ensure the operating conditions of the phase-locked loop and the motor, and improve the control efficiency and overall performance of the phase-locked loop and the motor. Moreover, the target frequency estimation value is fed back to the SOGI module and the PI control module to jointly achieve closed-loop control. Through the coordinated control of the SOGI module and the PI control module, the SOGI module and the PI control module can track the harmonic frequency change in real time, and thus can adapt to dynamic working conditions (such as frequency mutation, load fluctuation), enhance the dynamic response performance of the phase-locked loop, ensure long-term tracking accuracy, and also improve the dynamic response accuracy and robustness of the whole method, and improve the control efficiency of the whole method. The overall estimation method is applicable to the sensorless control scenario under high-noise environment, providing an effective solution for low-cost and high-reliability motor drive. Description of the Drawings

[0051] By reading the following detailed description of the preferred embodiments, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of illustrating the preferred embodiments and are not considered to be a limitation of the present invention. And throughout the drawings, the same reference numerals are used to represent the same components. In the drawings:

[0052] Figure 1 Shows the step flow schematic diagram of the method for estimating the rotor speed and position of the phase-locked loop in the embodiment of the present invention;

[0053] Figure 2 Shows the structural schematic diagram of the phase-locked loop in the embodiment of the present invention;

[0054] Figure 3 Shows the internal structural schematic diagram of the SOGI module in the embodiment of the present invention;

[0055] Figure 4 Shows the internal structural schematic diagram of the PI control module in the embodiment of the present invention. Detailed Embodiments

[0056] Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided so that the present disclosure can be more thoroughly understood and the scope of the present disclosure can be fully conveyed to those skilled in the art.

[0057] Embodiment 1

[0058] The first embodiment of the present invention provides a method for estimating the rotational speed and position of a rotor of a phase-locked loop, as Figure 1 shown, including:

[0059] S101, obtaining an estimated value of the extended back electromotive force of the motor and an estimated value of the current frequency;

[0060] S102, preprocessing the estimated value of the extended back electromotive force to obtain an input signal of a second-order generalized integrator module (SOGI module);

[0061] S103, based on the estimated value of the current frequency, performing harmonic interference processing on the input signal through the SOGI module to obtain a target fundamental component, where the harmonic interference processing is a process of suppressing harmonics in the input signal in real time through the estimated value of the current center frequency;

[0062] S104, based on the target fundamental component and the estimated value of the current frequency, dynamically adjusting the proportional gain and integral gain of the PI control module through the PI control module to obtain an estimated value of the target frequency;

[0063] S105, according to the estimated value of the target frequency, obtaining an estimated value of the target rotational speed and an estimated value of the target position of the rotor, and using the estimated value of the target frequency as the next frequency estimated value of the estimated value of the current frequency, and feeding it back to the SOGI module and the PI control module to achieve dynamic adjustment of the frequency estimated value of the phase-locked loop.

[0064] The method for estimating the rotational speed and position of the rotor of the phase-locked loop in this embodiment is applied to the phase-locked loop in this embodiment. As Figure 2 shown, Figure 2Schematic diagram of the structure of the phase-locked loop according to this embodiment. The phase-locked loop of this embodiment includes: a second-order generalized integrator module (SOGI) module and a PI control module connected in sequence. The SOGI module is used to output an output signal, that is, a target fundamental component, according to the input signal obtained from the estimated value of the extended back electromotive force of the motor and the estimated value of the current frequency. The PI control module is used to output a target frequency estimate according to the target fundamental component and the estimated value of the current frequency, so that the phase-locked loop obtains an estimated value of the target rotational speed and an estimated value of the target position of the rotor according to the target frequency estimate, and uses the target frequency estimate as the next frequency estimate of the current frequency estimate, and feeds it back to the SOGI module and the PI control module to achieve dynamic adjustment of the frequency estimate of the phase-locked loop. It should also be noted that the frequency estimate in this embodiment represents the electrical angular frequency of the rotor.

[0065] In this embodiment, after obtaining the estimated value of the extended back electromotive force of the motor and the estimated value of the current frequency, the estimated value of the extended back electromotive force is first preprocessed to obtain the input signal of the second-order generalized integrator module (SOGI) module. Then, based on the estimated value of the current frequency, the input signal is subjected to harmonic interference processing through the SOGI module to obtain the target fundamental component. Among them, the harmonic interference processing is the process of suppressing the harmonics in the input signal in real time through the estimated value of the current center frequency. Here, through a single SOGI module, the harmonics generated due to the nonlinearity of the inverter are eliminated, ensuring the accuracy and precision of the target fundamental component, thereby improving the accuracy and stability of the rotational speed and position of the rotor. Moreover, through a single SOGI filter, the burden on hardware resources and computational amount in the existing multi-filter scheme is greatly reduced.

[0066] Next, based on the target fundamental wave component and the current frequency estimate, the proportional gain and integral gain of the PI control module are dynamically adjusted through the PI control module to obtain the target frequency estimate. Here, based on the target fundamental wave component and the current frequency estimate, the PI control module is dynamically and adaptively adjusted, and the proportional gain and integral gain of the PI control module are dynamically optimized. This further ensures the accuracy and precision of the target frequency estimate, thereby enhancing the accuracy and stability of the rotor speed and position, and optimizing the overall control performance. Then, based on the target frequency estimate, the target rotor speed estimate and the target position estimate of the rotor are obtained. And the target frequency estimate is used as the next frequency estimate of the current frequency estimate and fed back to the SOGI module and the PI control module to dynamically adjust the frequency estimate of the phase-locked loop. In this way, based on the target frequency estimate with high accuracy and high precision, a rotor speed and position with high accuracy and high precision can be obtained to efficiently master the rotor and position of the rotor, ensure the operating conditions of the phase-locked loop and the motor, and improve the control efficiency and overall performance of the phase-locked loop and the motor. Moreover, the target frequency estimate is fed back to the SOGI module and the PI control module to jointly achieve closed-loop control. Through the coordinated control of the SOGI module and the PI control module, the SOGI module and the PI control module can track the harmonic frequency change in real time, and thus can adapt to dynamic working conditions (such as frequency mutation, load fluctuation), enhance the dynamic response performance of the phase-locked loop, ensure long-term tracking accuracy, and also improve the dynamic response accuracy and robustness of the whole method, and improve the control efficiency of the whole method. The overall estimation method is applicable to the sensorless control scenario under high-noise environment, providing an effective solution for low-cost and high-reliability motor drive.

[0067] Next, in combination with Figure 1 and Figure 2 the specific implementation steps of the method for estimating the rotor speed and position of the phase-locked loop in this embodiment are introduced in detail:

[0068] First, step S101 is executed to obtain the extended back electromotive force estimate and the current frequency estimate of the motor. Specifically, the extended back electromotive force estimate of the motor is output through a sliding mode observer. The extended back electromotive force estimate includes the extended back electromotive force estimate E alpha on the α-axis and the extended back electromotive force estimate E beta on the β-axis. The current frequency estimate is the frequency estimate in the current state of the phase-locked loop.

[0069] Next, step S102 is executed to preprocess the extended back electromotive force estimate to obtain the input signal of the second-order generalized integrator module, i.e., the SOGI module.

[0070] Specifically, the estimated value of the extended back electromotive force is normalized to obtain the processed estimated value of the extended back electromotive force. Among them, the processed estimated value of the extended back electromotive force includes: the processed estimated value of the extended back electromotive force on the α-axis, E alpha ’ and the processed estimated value of the extended back electromotive force on the β-axis, E beta ’. The purpose of the normalization process here is to normalize the amplitudes of the estimated value of the extended back electromotive force on the α-axis, E alpha and the estimated value of the extended back electromotive force on the β-axis, E beta to ensure the stability of the signal amplitude.

[0071] The normalization process is shown in formulas (1) and (2):

[0072]

[0073] During the process of obtaining E alpha ’ and E beta ’ or after obtaining E alpha ’ and E beta ’, the current position estimate of the rotor is obtained according to the current frequency estimate. Specifically, the current frequency estimate is integrated to obtain the current position estimate of the rotor, theta.

[0074] Next, according to the processed estimated value of the extended back electromotive force on the α-axis and the current position estimate, the unit extended back electromotive force vector on the α-axis is obtained, that is, the unit extended back electromotive force vector on the α-axis is E alpha ’ × cos(theta). And according to the processed estimated value of the extended back electromotive force on the β-axis and the current position estimate, the unit extended back electromotive force vector on the β-axis is obtained, that is, the unit extended back electromotive force vector on the β-axis is E beta ’ × sin(theta).

[0075] Subsequently, according to the unit extended back electromotive force vector on the α-axis and the unit extended back electromotive force vector on the β-axis, the input signal in-SOGI is obtained, as shown in formula (3):

[0076] in-SOGI = E alpha ’ × cos(theta) - E beta ’ × sin(theta) (3).

[0077] It should be noted that the input signal represents the phase error. According to the stable signal amplitude, a stable phase error, that is, the input signal, is obtained. After obtaining the input signal in-SOGI, the input signal is input into the SOGI module to enable the SOGI module to process the input signal.

[0078] Then, step S103 is executed. Based on the current frequency estimate, the input signal is processed for harmonic interference by the SOGI module to obtain the target fundamental component. Among them, the harmonic interference processing is to suppress the harmonics in the input signal in real time through the current center frequency estimate.

[0079] Specifically, in order to clearly understand the harmonic interference processing process of the SOGI module, it is necessary to first understand the internal structure of the SOGI module in detail. Figure 3 It is a schematic diagram of the internal structure of the SOGI module. As Figure 3 shown, the frequency estimate we outputs the extended frequency estimate through the target multiplier. Among them, the multiplier of the target multiplier is an even multiple, and the even multiple can be selected as 6 or 8. The input signal in-SOGI and the harmonic component of the SOGI module output the output signal out-SOGI of the SOGI module through the subtractor (i.e., the first subtractor). The output signal out-SOGI of the SOGI module is the fundamental component. The harmonic component also outputs the integrated harmonic component through the integrator (i.e., the first integrator). The integrated harmonic component and the extended frequency estimate output the first harmonic component through the multiplier (i.e., the first multiplier). The first harmonic component and the output signal out-SOGI output the second harmonic component through the subtractor (i.e., the second subtractor). The second harmonic component and the extended frequency estimate output the processed harmonic component through the multiplier (i.e., the second multiplier). The processed harmonic component outputs the harmonic component to the first subtractor through the integrator (i.e., the second integrator). In this way, the internal loop structure of the SOGI module is formed.

[0080] Based on the internal structure of the SOGI module, the harmonic interference processing process of the SOGI module is described: first, the target harmonic component is obtained according to the current frequency estimate and the current fundamental component of the SOGI module. Then, the target fundamental component is obtained according to the input signal and the target harmonic component. Among them, the specific process of obtaining the target harmonic component according to the current frequency estimate and the current fundamental component of the SOGI module is: multiplying the current frequency estimate we 当前 by a set multiple to obtain the extended frequency estimate ω r . Among them, the set multiple is an even multiple, which can be selected as 6 or 8, and the set multiple can also be set according to actual needs, such as taking a specific value. The first harmonic component is obtained according to the extended frequency estimate and the current harmonic component of the SOGI module. The second harmonic component is obtained according to the current fundamental component and the first harmonic component. The target harmonic component is obtained according to the second harmonic component and the extended frequency estimate.

[0081] Specifically, as Figure 3 shown, multiplying the current frequency estimate we 当前 ×6 to obtain the extended frequency estimate ω r , that is, ω r= we 当前 × 6. The current harmonic component X 当前 The integrated harmonic component X is obtained through integration processing 当前 · 1 / s. The integrated harmonic component X 当前 · 1 / s is multiplied by the extended frequency estimate ω r to obtain the first harmonic component X 当前 · 1 / s· ω r . The first harmonic component and the current fundamental component out-SOGI 当前 are subtracted to obtain the second harmonic component out-SOGI 当前 · K - X 当前 · 1 / s· ω r . Where K is the gain coefficient of the SOGI module. The second harmonic component is multiplied by the extended frequency estimate to obtain the processed harmonic component (out-SOGI 当前 · K - X 当前 · 1 / s· ω r ) ω r = out-SOGI 当前 · K· ω r - X 当前 · 1 / s· ω r 2 . The processed harmonic component is obtained through integration processing to obtain the target harmonic component. Where the target harmonic component is the next harmonic component of the current harmonic component, that is, the target harmonic component is used as the next current harmonic component. The target harmonic component is out-SOGI 当前 · K· ω r · 1 / s - X 当前 · 1 / s 2 · ω r 2 . It should be noted that in the SOGI module, the current frequency estimate is used as the center frequency in the current state of the SOGI module

[0082] In this embodiment, after the input signal is filtered by the SOGI module, the target fundamental component is extracted. Moreover, the SOGI module can dynamically and adaptively adjust its own center frequency to track the change of the fundamental frequency, ensuring real-time suppression of harmonics, especially the real-time suppression of the 6th harmonic. At the same time, through the feedback control mechanism, that is, by updating the frequency estimate value in real time to obtain the current frequency estimate value, the amplitude and phase of the output signal of the SOGI module (i.e., the target fundamental component) are adjusted to ensure that the output signal is consistent with the fundamental component of the input signal. In this way, through a single SOGI module, the harmonics generated by the inverter nonlinearity are eliminated, ensuring the accuracy and precision of the target fundamental component, thereby improving the accuracy and stability of the rotor speed and position. Moreover, with only a single SOGI filter, the burden on hardware resources and computing volume in the existing multi-filter scheme is greatly reduced. And only a single SOGI module filter can effectively suppress harmonics, eliminating the need for multi-filter design, simplifying the structure, reducing the computing resource requirements and implementation complexity, and improving the cost performance of the real-time control process.

[0083] Based on the internal structure of the SOGI module and the harmonic interference processing process of the SOGI module, the transfer function of the SOGI module is derived. The derivation process is as follows:

[0084] out-SOGI = in-SOGI - X(4), where X represents the harmonic component, and the harmonic component is obtained according to the frequency estimate value and the fundamental component. According to formula (4), formula (5) is obtained, that is, X = in-SOGI - out-SOGI(5).

[0085]

[0086] According to formula (6), formula

[0087] According to formula (7), formula s 2 X + ω r 2 X = out-SOGI·K·s·ω r (8);

[0088] According to formula (8), formula

[0089] Combining formula (9) and formula (5), formula (10) is obtained. Where s is the complex frequency variable, representing the complex frequency in the Laplace transform: s = σ + jω, K is the gain coefficient of the SOGI module, ω r is the extended frequency estimate value obtained by multiplying the current frequency estimate value by a set multiple, that is, ω r= we × 6, where we is the frequency estimation value, i.e., the current frequency estimation value.

[0090] In addition, the set multiple of this embodiment is preferably 6. The reason for choosing 6 as the set multiple is as follows: Since the structural design of the motor body cannot reach the ideal state, there are problems such as cogging effect, non-sinusoidal winding distribution, and structural defects of the rotor permanent magnet. The distribution of the rotor permanent magnet flux linkage within the air-gap circumference is non-sinusoidal, causing distortion of the motor back-EMF waveform. Since the three-phase windings of the motor are star-connected symmetrically, the back-EMF waveform is half-wave symmetric, that is, the back-EMF waveform of the winding does not contain even harmonics and odd harmonics whose orders are integer multiples of 3. Therefore, it mainly contains higher harmonics such as the 5th and 7th harmonics. In actual simulation, even harmonics or harmonics that are integer multiples of 3 are small but exist, which is just the default idealized effect. When the winding current of the motor is large, these will cause magnetic saturation of the motor magnetic circuit, making the magnetic field distortion more serious and further increasing the torque ripple of the motor.

[0091] According to the rotating magnetic field theory of AC motors, the fundamental magnetic flux linkage of a three-phase permanent magnet synchronous motor rotates synchronously with the rotor. The 5th harmonic magnetic flux linkage rotates in the opposite direction to the fundamental wave, and the rotation speed is -5ω; the rotation direction of the 7th magnetic flux linkage is the same as that of the fundamental wave, and the speed is 7ω. The back-EMF harmonics generated by the 5th and 7th harmonic magnetic flux linkages will both cause 6th-order pulsation of the electromagnetic torque of the permanent magnet synchronous motor. The interference of the 12th and 18th harmonics can also be considered later.

[0092] The triggering and commutation of the three-phase inverter during normal operation will cause harmonic components of 6k times (especially 6, 12, 18, …) to appear in the voltage and current. Among them, the 6th harmonic often has the largest amplitude and is the most typical. For methods based on current sampling or high-frequency signal injection for speed / position estimation, the existence of the 6th harmonic will interfere with the estimation accuracy, causing jitter or distortion of the observed quantity.

[0093] Moreover, the influence of the 6th harmonic on the observation is as follows:

[0094] 1. Noise and fluctuation: When it is necessary to obtain the motor speed or rotor position signal with high precision, the fluctuation of the measurement signal after superimposing the 6th harmonic increases.

[0095] 2. Torque ripple: The 6th harmonic is also likely to bring additional torque ripple and mechanical vibration, which is not conducive to further control optimization.

[0096] 3. Burden on sensors or control loops: Excessive harmonic components will increase the burden on the control loop, making it difficult for the PI controller to respond quickly and accurately to the fundamental wave or high-frequency injection signal.

[0097] Therefore, in this embodiment, the SOGI module eliminates the harmonics generated due to the non-linearity of the inverter, especially the influence of the 6th harmonic in the rotor position estimation, thereby ensuring high-precision and stable speed and position information. It also enables the SOGI module to dynamically and adaptively adjust its own center frequency, achieve tracking of the fundamental frequency change, ensure real-time suppression of harmonics, guarantee the accuracy and precision of the target fundamental component, and thus improve the accuracy and stability of the rotor speed and position. Additionally, with a single SOGI filter, the burden on hardware resources and computational complexity in the existing multi-filter scheme is greatly reduced.

[0098] Then, step S104 is executed. Based on the target fundamental component and the current frequency estimate, the proportional gain and integral gain of the PI control module are dynamically adjusted through the PI control module to obtain the target frequency estimate.

[0099] Specifically, to clearly understand the dynamic adjustment process of the proportional gain and integral gain of the PI control module to itself, it is necessary to first understand the internal structure of the PI control module in detail. Figure 3 It is a schematic diagram of the internal structure of the PI control module. As Figure 3 shown, the frequency estimate we, the reference frequency estimate ref - we, the proportional base gain K p-base , the integral base gain K i-base , the proportional adaptive adjustment coefficient α, and the integral adaptive adjustment coefficient β are input into the PI controller (Proportional Integral Controller) of the PI control module. The PI controller processes these input parameters and outputs the proportional gain K p and the integral gain K i , as shown in formulas (11) and (12).

[0100] K p =K p-base +α·|e| (11)

[0101] K i =K i-base +β·|e| (12).

[0102] Where e is the difference between the frequency estimate we and the reference frequency estimate ref - we.

[0103] After obtaining the proportional gain K p and the integral gain K i , the integral gain K i is multiplied by the target fundamental component (i.e., the output signal out - SOGI of the SOGI module) and then integrated to obtain the first frequency value K i ·out - SOGI·1 / s. The proportional gain Kp After multiplying with the target fundamental wave component (i.e., the output signal out-SOGI of the SOGI module), the second frequency value K is obtained. p ·out-SOGI. Add the first frequency value and the second frequency value to obtain the target frequency estimation value we. 目标 , that is, we 目标 =K i ·out-SOGI·1 / s + K p ·out-SOGI. Then, use the target frequency estimation value as the next frequency estimation value of the current frequency estimation value, that is, the next current frequency estimation value, and feedback it to the PI controller. This can realize the dynamic optimization and adjustment of the proportional gain and integral gain of the PI controller, so that the PI control module and the PI controller can dynamically adapt to the working conditions.

[0104] Based on the internal structure of the PI control module, the dynamic adjustment process of the proportional gain and integral gain of the PI control module is as follows: Step a, obtain the proportional gain and integral gain according to the current frequency estimation value, the reference frequency estimation value of the PI controller of the PI control module, the proportional basic gain, the integral basic gain, the proportional adaptive adjustment coefficient, and the integral adaptive adjustment coefficient. Step b, obtain the first frequency value according to the integral gain and the target fundamental wave component, and obtain the second frequency value according to the proportional gain and the target fundamental wave component. Step c, obtain the target frequency estimation value according to the first frequency value and the second frequency value.

[0105] Specifically, the process of step a is to input the difference e between the current frequency estimation value we 当前 and the reference frequency estimation value ref-we, the proportional basic gain K p-base , the integral basic gain K i-base , the proportional adaptive adjustment coefficient α, and the integral adaptive adjustment coefficient β into the PI controller of the PI control module. Based on the control processing process of formulas (11) and (12), the PI controller outputs the proportional gain K p and the integral gain K i .

[0106] The process of step b is to multiply the integral gain K i with the target fundamental wave component (i.e., the output signal out-SOGI of the SOGI module) and then integrate to obtain the first frequency value K i ·out-SOGI·1 / s. Multiply the proportional gain K p with the target fundamental wave component (i.e., the output signal out-SOGI of the SOGI module) to obtain the second frequency value K p ·out-SOGI.

[0107] In the process of step c, the first frequency value is added to the second frequency value to obtain the target frequency estimate we 目标 , that is, we 目标 = K i ·out - SOGI·1 / s + K p ·out - SOGI. The target frequency estimate is used as the next frequency estimate of the current frequency estimate, that is, the next current frequency estimate, and is fed back to the PI controller

[0108] In this embodiment, the PI control module, based on the current frequency estimate and the target fundamental component output by the SOGI, dynamically adjusts the proportional gain K p and the integral gain K i to obtain a new frequency estimate we, that is, the target frequency estimate. In this way, the PI control module realizes real - time tracking of frequency changes and achieves collaborative optimization of harmonic suppression with the SOGI module. This further ensures the accuracy and precision of the target frequency estimate, thereby enhancing the accuracy and stability of the rotor speed and position, and optimizing the overall control performance. Moreover, through the setting of the PI control module, the computational resource requirements and implementation complexity are also reduced, and the cost - effectiveness of the real - time control process is improved

[0109] In addition, there is another dynamic adjustment process for the proportional gain and integral gain of the PI control module in this embodiment, which can replace the control processing process of the PI controller based on formulas (11) and (12). The PI controller obtains the proportional gain and integral gain based on the module inference model and the current frequency estimate. Among them, the module inference model includes the Mamdani model and the Sugeno model. According to the integral gain and the target fundamental component, the first frequency value is obtained, and according to the proportional gain and the target fundamental component, the second frequency value is obtained. According to the first frequency value and the second frequency value, the target frequency estimate is obtained. In this dynamic adjustment process of the proportional gain and integral gain of the PI control module, except that the obtaining process of the proportional gain and integral gain is different from step a in the previous dynamic adjustment process of its own proportional gain and integral gain, the remaining processes are the same as the other steps in the previous one and will not be elaborated. This dynamic adjustment process of the proportional gain and integral gain of the PI control module can reduce the algorithm complexity and improve the computational processing efficiency

[0110] Finally, step S105 is executed. According to the target frequency estimate, the target speed estimate and the target position estimate of the rotor are obtained, and the target frequency estimate is used as the next frequency estimate of the current frequency estimate and fed back to the SOGI module and the PI control module to realize dynamic adjustment of the frequency estimate of the phase - locked loop

[0111] Specifically, the relationship between the rotational speed and position of the rotor and the estimated frequency is shown in the following formula:

[0112] where wm is the mechanical rotational speed of the motor, P is the number of pole pairs of the motor, and we is the estimated frequency.

[0113] where N r represents the estimated rotational speed of the rotor.

[0114] theta = ∫we dt (15), where theta represents the estimated position of the rotor.

[0115] Based on formulas (13)-(15), the target estimated rotational speed and target estimated position of the rotor are obtained from the target estimated frequency. And the target estimated frequency is used as the next estimated frequency of the current estimated frequency and fed back to the SOGI module and the PI control module to dynamically adjust the estimated frequency of the phase-locked loop.

[0116] In this way, the newly estimated frequency we output by the PI control module is continuously fed back to the SOGI module and the adaptive PI control module to form a closed-loop control, realizing the collaborative optimization of harmonic suppression and frequency tracking. The SOGI module and the PI control module perform collaborative optimization control, dynamically adjust their own parameters, improve the accuracy and precision of the estimated values of the rotational speed and position of the rotor by the phase-locked loop, thereby eliminating the steady-state error and enhancing the accuracy and precision of the output signal of the phase-locked loop. It can also dynamically adapt to the estimated values of the rotational speed and position of the rotor, enhance the dynamic response performance of the phase-locked loop, and ensure long-term tracking accuracy.

[0117] One or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages:

[0118] In this embodiment, after obtaining the estimated value of the extended back electromotive force of the motor and the current estimated frequency, the estimated value of the extended back electromotive force is first preprocessed to obtain the input signal of the second-order generalized integrator module SOGI module. Then, based on the current estimated frequency, the input signal is processed for harmonic interference by the SOGI module to obtain the target fundamental component. Among them, the harmonic interference processing is the process of suppressing the harmonics in the input signal in real time through the current estimated center frequency. Here, through a single SOGI module, the harmonics generated due to the nonlinearity of the inverter are eliminated, ensuring the accuracy and precision of the target fundamental component, thereby improving the accuracy and stability of the rotational speed and position of the rotor. And, through a single SOGI filter, the burden on hardware resources and the amount of computation in the existing multi-filter scheme is greatly reduced.

[0119] Next, based on the target fundamental wave component and the current frequency estimate, the proportional gain and integral gain of the PI control module are dynamically adjusted through the PI control module to obtain the target frequency estimate. Here, based on the target fundamental wave component and the current frequency estimate, the PI control module is dynamically and adaptively adjusted, and the proportional gain and integral gain of the PI control module are dynamically optimized. In this way, the accuracy and precision of the target frequency estimate are further ensured, thereby enhancing the accuracy and stability of the rotor speed and position, and optimizing the overall control performance. Then, according to the target frequency estimate, the target rotor speed estimate and the target position estimate of the rotor are obtained. And the target frequency estimate is used as the next frequency estimate of the current frequency estimate and fed back to the SOGI module and the PI control module to dynamically adjust the frequency estimate of the phase-locked loop. In this way, based on the target frequency estimate with high accuracy and high precision, the rotor speed and position with high accuracy and high precision can be obtained to efficiently master the rotor and position of the rotor, ensure the working conditions of the phase-locked loop and the motor, and improve the control efficiency and overall performance of the phase-locked loop and the motor. Moreover, the target frequency estimate is fed back to the SOGI module and the PI control module to jointly achieve closed-loop control. Through the coordinated control of the SOGI module and the PI control module, the SOGI module and the PI control module can track the harmonic frequency change in real time, and thus can adapt to dynamic working conditions (such as frequency mutation, load fluctuation), enhance the dynamic response performance of the phase-locked loop, ensure long-term tracking accuracy, and also improve the dynamic response accuracy and robustness of the whole method, and improve the control efficiency of the whole method. The overall estimation method is applicable to the sensorless control scenario in a high-noise environment, providing an effective solution for low-cost and high-reliability motor drives..

[0120] Embodiment 2

[0121] Based on the same inventive concept, the second embodiment of the present invention also provides a phase-locked loop, as Figure 2 shown, for applying the method for estimating the rotor speed and position of the phase-locked loop as described in Embodiment 1. The phase-locked loop includes:

[0122] An SOGI module, configured to, after obtaining the extended back electromotive force estimate and the current frequency estimate of the motor, and preprocessing the extended back electromotive force estimate to obtain the input signal of the second-order generalized integrator module SOGI module, perform harmonic interference processing on the input signal based on the current frequency estimate to obtain a target fundamental wave component, where the harmonic interference processing is a process of suppressing the harmonics in the input signal in real time through the current center frequency estimate;

[0123] The PI control module is used to dynamically adjust the proportional gain and integral gain of the PI control module based on the target fundamental component and the current frequency estimate to obtain a target frequency estimate, so as to obtain an estimated target speed and an estimated target position of the rotor through the target frequency estimate, and use the target frequency estimate as the next frequency estimate of the current frequency estimate and feedback it to the SOGI module and the PI control module to achieve dynamic adjustment of the frequency estimate of the phase-locked loop.

[0124] As an alternative embodiment, as Figure 3 shown, the SOGI module includes: a first subtractor, a second subtractor, a first integrator, a second integrator, a first multiplier, a second multiplier, and a target multiplier;

[0125] The target multiplier is used to multiply the current frequency estimate by a set multiple to obtain an extended frequency estimate, where the set multiple is an even multiple;

[0126] The first subtractor is used to output a fundamental component according to the received input signal and harmonic component;

[0127] The first integrator is used to receive the harmonic component and perform an integration process on the harmonic component to output the integrated harmonic component;

[0128] The first multiplier is used to obtain a first harmonic component according to the received integrated harmonic component and the extended frequency estimate;

[0129] The second subtractor is used to obtain a second harmonic component according to the received fundamental component and the first harmonic component;

[0130] The second multiplier is used to obtain a processed harmonic component according to the received second harmonic component and the extended frequency estimate;

[0131] The second integrator is used to perform an integration process on the received processed harmonic component to obtain the harmonic component.

[0132] Since the phase-locked loop introduced in this embodiment is the phase-locked loop used to implement the method for estimating the rotor speed and position of the phase-locked loop in Embodiment 1 of the present application, based on the method for estimating the rotor speed and position of the phase-locked loop introduced in Embodiment 1 of the present application, those skilled in the art can understand the specific implementation manner of the phase-locked loop in this embodiment and its various variations. Therefore, the specific implementation of how this phase-locked loop implements the method in Embodiment 1 of the present application will not be described in detail here. As long as those skilled in the art implement the phase-locked loop used in the method for estimating the rotor speed and position of the phase-locked loop in Embodiment 1 of the present application, it falls within the scope of protection of the present application.

[0133] Embodiment III

[0134] Based on the same inventive concept, the third embodiment of the present invention further provides a synchronous motor, including: the phase-locked loop as described in Embodiment II.

[0135] The synchronous motor of this embodiment includes, but is not limited to, a permanent magnet synchronous motor, a sensorless controlled permanent magnet synchronous motor, and a brushless DC motor.

[0136] Those skilled in the art should understand that although the preferred embodiments of the present invention have been described, once the basic creative concepts are known to those skilled in the art, additional changes and modifications can be made to these embodiments. Therefore, the appended claims are intended to be construed to include the preferred embodiments as well as all changes and modifications falling within the scope of the present invention.

[0137] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these modifications and variations.

Claims

1. A method for estimating the rotational speed and position of a rotor of a phase-locked loop, characterized in that, Including: Obtaining an extended back electromotive force estimation value and a current frequency estimation value of the motor; Preprocessing the extended back electromotive force estimation value to obtain an input signal of a second-order generalized integrator module (SOGI module); Based on the current frequency estimation value, performing harmonic interference processing on the input signal through the SOGI module to obtain a target fundamental component, wherein the harmonic interference processing is a process of suppressing harmonics in the input signal in real time through the current center frequency estimation value; Based on the target fundamental component and the current frequency estimation value, dynamically adjusting the proportional gain and integral gain of the PI control module through the PI control module to obtain a target frequency estimation value; According to the target frequency estimation value, obtaining a target rotational speed estimation value and a target position estimation value of the rotor, and using the target frequency estimation value as the next frequency estimation value of the current frequency estimation value and feeding it back to the SOGI module and the PI control module to achieve dynamic adjustment of the frequency estimation value of the phase-locked loop.

2. The method according to claim 1, characterized in that, The performing, based on the current frequency estimation value, harmonic interference processing on the input signal through the SOGI module to obtain a target fundamental component includes: Obtaining a target harmonic component according to the current frequency estimation value and the current fundamental component of the SOGI module; Obtaining the target fundamental component according to the input signal and the target harmonic component.

3. The method according to claim 2, wherein The obtaining the target harmonic component according to the current frequency estimation value and the current fundamental component of the SOGI module includes: Multiplying the current frequency estimation value by a set multiple to obtain an extended frequency estimation value, wherein the set multiple is an even multiple; Obtaining a first harmonic component according to the extended frequency estimation value and the current harmonic component of the SOGI module; Obtaining a second harmonic component according to the current fundamental component and the first harmonic component; Obtaining the target harmonic component according to the second harmonic component and the extended frequency estimation value.

4. The method according to claim 3, characterized in that, The performing, based on the current frequency estimation value, harmonic interference processing on the input signal through the SOGI module to obtain a target fundamental component further includes: Obtaining a transfer function of the SOGI module according to the input signal, the current frequency estimation value and the target fundamental component, wherein the transfer function of the SOGI module is: Among them, in-SOGI represents the input signal, out-SOGI represents the target fundamental wave component, s is a complex frequency variable, representing the complex frequency in the Laplace transform: s = σ + jω, K is the gain coefficient of the SOGI module, ω r is the extended frequency estimate obtained by multiplying the current frequency estimate by a set multiple.

5. The method according to claim 2, wherein The dynamically adjusting, based on the target fundamental component and the current frequency estimation value, the proportional gain and integral gain of the PI control module through the PI control module to obtain a target frequency estimation value includes: Obtaining the proportional gain and the integral gain according to the current frequency estimation value, the reference frequency estimation value of the PI controller of the PI control module, the proportional basic gain, the integral basic gain, the proportional adaptive adjustment coefficient and the integral adaptive adjustment coefficient; Obtaining a first frequency value according to the proportional gain and the target fundamental component, and obtaining a second frequency value according to the integral gain and the target fundamental component; Obtaining the target frequency estimation value according to the first frequency value and the second frequency value.

6. The method according to claim 2, wherein Based on the target fundamental wave component and the current frequency estimation value, dynamically adjusting the proportional gain and integral gain of the PI control module through a PI control module to obtain a target frequency estimation value, including: The PI controller of the PI control module obtains the proportional gain and the integral gain based on a module inference model and the current frequency estimation value, wherein the module inference model includes a Mamdani model and a Sugeno model; Obtaining a first frequency value according to the integral gain and the target fundamental wave component, and obtaining a second frequency value according to the proportional gain and the target fundamental wave component; Obtaining the target frequency estimation value according to the first frequency value and the second frequency value.

7. The method according to claim 2, wherein Preprocessing the extended back electromotive force estimation value to obtain an input signal of a second-order generalized integrator module (SOGI module), including: Normalizing the extended back electromotive force estimation value to obtain a processed extended back electromotive force estimation value, wherein the processed extended back electromotive force estimation value includes a processed extended back electromotive force estimation value of the α-axis and a processed extended back electromotive force estimation value of the β-axis; Obtaining a current position estimation value of the rotor according to the current frequency estimation value; Obtaining a unit extended back electromotive force vector of the α-axis according to the processed extended back electromotive force estimation value of the α-axis and the current position estimation value, and obtaining a unit extended back electromotive force vector of the β-axis according to the processed extended back electromotive force estimation value of the β-axis and the current position estimation value; Obtaining the input signal according to the unit extended back electromotive force vector of the α-axis and the unit extended back electromotive force vector of the β-axis.

8. A phase-locked loop, characterized in that, For applying the method for estimating the rotor speed and position of a phase-locked loop as described in any one of claims 1-7, the phase-locked loop includes: An SOGI module, configured to, after obtaining an extended back electromotive force estimation value and a current frequency estimation value of a motor, and preprocessing the extended back electromotive force estimation value to obtain an input signal of a second-order generalized integrator module (SOGI module), perform harmonic interference processing on the input signal based on the current frequency estimation value to obtain a target fundamental wave component, wherein the harmonic interference processing is a process of suppressing harmonics in the input signal in real time through the current center frequency estimation value; A PI control module, configured to dynamically adjust the proportional gain and integral gain of the PI control module based on the target fundamental wave component and the current frequency estimation value to obtain a target frequency estimation value, so as to obtain a target speed estimation value and a target position estimation value of the rotor through the target frequency estimation value, and use the target frequency estimation value as the next frequency estimation value of the current frequency estimation value and feedback it to the SOGI module and the PI control module to realize dynamic adjustment of the frequency estimation value of the phase-locked loop.

9. The phase-locked loop according to claim 8, wherein, The SOGI module includes: a first subtractor, a second subtractor, a first integrator, a second integrator, a first multiplier, a second multiplier, and a target multiplier; The target multiplier is configured to multiply the current frequency estimate by a set multiple to obtain an extended frequency estimate, where the set multiple is an even multiple; The first subtractor is configured to output a fundamental component according to the received input signal and harmonic component; The first integrator is configured to receive the harmonic component and perform an integration process on the harmonic component to output the integrated harmonic component; The first multiplier is configured to obtain a first harmonic component according to the received integrated harmonic component and the extended frequency estimate; The second subtractor is configured to obtain a second harmonic component according to the received fundamental component and the first harmonic component; The second multiplier is configured to obtain a processed harmonic component according to the received second harmonic component and the extended frequency estimate; The second integrator is configured to perform an integration process on the received processed harmonic component to obtain the harmonic component.

10. A synchronous motor, characterized in that, Comprising: The phase-locked loop according to any one of claims 8-9.

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