Real-time estimation method, recording medium and system for rotor position of permanent magnet synchronous motor

Abstract

The invention belongs to the technical field of motor control, and particularly relates to a real-time estimation method for the rotor position of a permanent magnet synchronous motor, which comprises the following steps of: extracting effective flux linkage phase information of the motor and carrying out differential processing on effective flux linkage phases sampled for two adjacent times to obtain a feedforward estimation rotating speed component; constructing a position error signal, sending the position error signal to a phase-locked loop for proportional-integral closed-loop adjustment, and obtaining a closed-loop estimation rotating speed component after low-pass filtering; the method optimizes the rotation speed estimation, has high portability, is suitable for various implementations based on a back electromotive force model in a permanent magnet synchronous motor position sensorless control method, and has the advantages of low-pass filtering after the two rotation speed components are added to obtain the estimated rotation speed # imgabs0 #, integration is carried out on the # imgabs1 #, and the rotor position # imgabs2 # of the permanent magnet synchronous motor is obtained. And the dynamic response of the traditional position sensorless control method can be obviously improved. The invention also provides a non-transitory readable recording medium storing the program of the method and a system comprising the medium, and the program can be called through a processing circuit to execute the method.

Description

Technical Field

[0001] The invention belongs to the technical field of motor control and discloses a real-time estimation method, recording medium and system for the rotor position of a permanent magnet synchronous motor. Background Art

[0002] Permanent magnet synchronous motor position sensorless control technology has the advantages of simplifying the physical structure of the drive system, improving the anti-interference ability of the drive system and saving the cost of the drive system. It has become one of the indispensable core technologies in the application of electric drive engineering.

[0003] When the motor running speed is higher than 5% of the rated speed, the signal-to-noise ratio of the back-EMF signal at the motor port is significantly improved. In this case, the back-EMF can be used to obtain the rotor flux information, and then a phase-locked loop (PLL) is used to lock the phases of the rotor fluxes that are orthogonal to each other in the stationary coordinate system, thereby realizing real-time estimation of the rotor position and speed of the permanent magnet synchronous motor.

[0004] However, when a traditional phase-locked loop is used to lock the orthogonal rotor flux phases in a stationary coordinate system, a closed-loop negative feedback adjustment mechanism is required. Whenever the input signal of the phase-locked loop changes, the phase-locked loop always needs to go through a certain adjustment time to reach a steady state, which affects the dynamic response performance of the motor rotor position estimation. For example, in practical applications, when the given speed of the motor changes drastically, due to the limitations of the phase-locked loop adjustment process, the estimated position will lag behind the actual position, and the instantaneous deviation between the estimated speed and the given speed will increase significantly, which reduces the speed and torque response of the motor, easily causes severe current fluctuations, and even causes the drive system to become unstable in severe cases.

[0005] It can be said that the response speed of the traditional phase-locked loop restricts the high acceleration capability of the position-free electric drive system and its control ability of step commands. In some permanent magnet synchronous motor drive systems with high dynamic speed regulation requirements, this limitation seriously reduces the speed regulation performance of the permanent magnet synchronous motor drive system.

[0006] How to obtain accurate motor rotor position estimation results in real time when the motor speed undergoes a large sudden change is a problem that technical personnel in this field urgently need to solve. Summary of the invention

[0007] In view of the above problems, the present invention provides a real-time estimation method for the rotor position of a permanent magnet synchronous motor, comprising the following steps:

[0008] The effective flux is extracted using the voltage and current signal data of the motor port, and normalized to obtain the effective flux phase information with unit amplitude and orthogonal phase.

[0009] The effective flux phase of two adjacent samples is differentiated and then passed through a low-pass filter to obtain the feedforward estimated speed component.

[0010] Construct a position error signal, send the position error signal to the phase-locked loop for proportional-integral closed-loop regulation, and obtain the closed-loop estimated speed component after low-pass filtering

[0011] The feedforward estimated speed component With closed loop estimated speed component Add, low-pass filter the addition result, and get the final estimated speed right After integration, the estimated rotor position of the permanent magnet motor is obtained

[0012] Preferably, extracting the effective flux linkage includes the steps of integrating the back electromotive force using a first-order inertial filter, and performing amplitude and phase compensation on the obtained stator flux linkage data.

[0013] Preferably, the first-order inertial filter is formed by a high-pass filter connected in series with an integrator, and its transfer function is:

[0014] In the formula, ω H represents the cutoff frequency of the high-pass filter, and S represents the complex frequency variable in the Laplace transform.

[0015] Preferably, the calculation of the compensation amount in the amplitude and phase compensation uses the following method:

[0016]

[0017] Where Amp com Represents the stator flux amplitude compensation, Pha com Represents the compensation amount of the stator flux phase, ω e Represents the rotor speed.

[0018] Preferably, the normalization method is to first square the effective magnetic flux components of the α-axis and the β-axis respectively, take the sum and then take the square root to obtain the amplitude of the effective magnetic flux vector, and then divide the effective magnetic flux components of the α-axis and the β-axis by the amplitude of the effective magnetic flux vector respectively, thereby realizing the normalization of the effective magnetic flux components of the α-axis and the β-axis, and obtaining the normalized magnetic flux phase information of the α-axis and the normalized magnetic flux phase information of the β-axis.

[0019] Preferably, the differential processing of the effective flux phase of two adjacent samples includes using the current sampled flux phase information and the last sampled flux phase information to make a difference, and then dividing it by the sampling time to obtain the feedforward estimated speed component

[0020]

[0021] In the formula, is the feedforward estimated speed component, and It represents the phase of the effective flux method at the current time n and the previous time n-1, and ΔT is the time interval between the two estimated times.

[0022] Preferably, the method for constructing the position error signal is: according to the principle of heterodyne method, the position error signal

[0023]

[0024] In the formula, Δθ e is the original position error, θ re is the real phase information of the effective flux, is the estimated phase information of the effective flux linkage method.

[0025] Another embodiment of the present invention is to provide a non-transitory readable recording medium for storing one or more programs including a plurality of instructions. When the instructions are executed, the processing circuit will execute the above-mentioned method for real-time estimation of the rotor position of a permanent magnet synchronous motor.

[0026] Another embodiment of the present invention is to provide a real-time estimation system for the rotor position of a permanent magnet synchronous motor, comprising a processing circuit and a memory electrically coupled thereto, wherein the memory is configured to store at least one program, wherein the program includes a plurality of instructions, and the processing circuit runs the program to execute the above-mentioned real-time estimation method for the rotor position of a permanent magnet synchronous motor.

[0027] Compared with the prior art, the method, recording medium and system for real-time estimation of the rotor position of a permanent magnet synchronous motor provided by the present invention have the following beneficial effects:

[0028] 1. Wide applicability and high portability: This method can be applied to various implementations of the back-EMF model in the position sensorless control method of permanent magnet synchronous motor or induction motor, and can significantly improve the dynamic response of the traditional position sensorless control method, so that it can show high efficiency and applicability in various application scenarios.

[0029] 2. Optimized speed estimation mechanism: The speed estimation process uses a speed feedforward combined with a phase-locked loop to estimate the speed. The feedforward speed estimation component is obtained by differential processing of the flux phase information. The speed component can be understood as the coarse adjustment component of the estimated speed, which makes the estimated speed quickly approach the actual speed; the phase-locked loop adjusts the position error signal in a closed loop to obtain the closed-loop estimated speed component This speed component can be understood as a fine-tuning component of the estimated speed, eliminating the static error of the estimated speed. With closed loop estimated speed component The sum is taken as the final estimated speed right After integration, the estimated rotor position of the permanent magnet motor is obtained The proposed method realizes real-time and accurate estimation of the motor rotor position when the motor speed undergoes a large sudden change, which is beneficial to the high dynamic and high precision speed regulation of the permanent magnet synchronous motor drive system, and significantly improves the high acceleration capability of the drive system and the control capability of step instructions.

[0030] 3. Simple and practical design: This method has a simple structure and excellent dynamic performance, and can meet the engineering requirements for high dynamic speed regulation of permanent magnet synchronous motors. This advantage makes the present invention more applicable in practical engineering applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a block diagram of the principle of extracting effective flux linkage using a first-order inertial integrator in an embodiment of the present invention;

[0032] Figure 2 This is a block diagram of the principle of constructing an effective flux normalization signal in an embodiment of the present invention;

[0033] Figure 3 Extracting the feedforward estimated speed component in the embodiment of the present invention Schematic diagram;

[0034] Figure 4 Extracting the closed-loop estimated speed component in the embodiment of the present invention Schematic diagram;

[0035] Figure 5 An overall principle block diagram of a method for estimating the position of a permanent magnet motor according to an embodiment of the present invention;

[0036] Figure 6 This is a performance verification diagram of an embodiment of the present invention on a certain 80kW permanent magnet drive platform;

[0037] Figure 7 This is a performance verification diagram of an embodiment of the present invention on a permanent magnet drive platform of a high-speed air compressor. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be described below in conjunction with the drawings in the embodiments of the present invention. The described embodiments are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making innovative efforts are within the scope of protection of the present invention.

[0039] like Figure 5 As shown, a method for real-time estimation of the rotor position of a permanent magnet synchronous motor provided by the present invention comprises the following steps:

[0040] Step A) Extract the effective flux of the motor through the back EMF: The voltage and current signals at the motor port are combined with the concept of effective flux, and the effective flux is extracted using a first-order inertial integrator, and the amplitude and phase compensation of the effective flux is performed (see Figure 1 ).

[0041] Step B) normalize the effective flux signal: after obtaining the effective flux, perform normalization operation on it. The purpose of normalization operation is to obtain the flux phase information with unit amplitude and phase orthogonality, thereby eliminating the influence of flux amplitude and rotor speed change on the phase-locked loop feedforward gain, and improving the stability of the position estimation closed loop.

[0042] Step C) Extracting the feedforward estimated speed component by flux phase differential The differential link is used to differentiate the normalized flux phase between two adjacent samples, and then the feedforward estimated speed component is obtained through the low-pass filtering link. Make the estimated speed quickly approach the actual speed.

[0043] Step D) Phase-locked loop extracts closed-loop estimated speed component First, the position error signal Δθ is constructed based on the concept of trigonometric function equivalent infinitesimal, and then the phase-locked loop is used to close the position error signal to obtain the closed-loop estimated speed component. Eliminate static errors in estimated speed.

[0044] Step E) Feedforward estimation of speed component With closed loop estimated speed component Add together to form the final estimated speed The feedforward estimated speed component With closed loop estimated speed component Add and appropriately low-pass filter the result to get the final estimated speed right After integration, the estimated rotor position of the permanent magnet motor is obtained

[0045] In step A) of this embodiment, the specific implementation of extracting the effective flux of the motor through the back electromotive force is as follows: in the two-phase stationary α-β coordinate system, the relationship between the stator flux, the stator current and the rotor permanent magnet flux of the permanent magnet synchronous motor can be expressed as: ψ r =ψ s -L αβ I s

[0046] In the formula, ψ r represents the rotor permanent magnet flux vector; ψ s represents the stator flux vector; L αβ and I s Represent the inductance matrix and the current matrix respectively. For a salient pole permanent magnet synchronous motor, the scalar form of the inductance matrix can be expressed as

[0047]

[0048] Where, L α , L β Respectively represent the α and β axis inductance; L d , L q Represents the d-axis and q-axis inductances respectively; θ e Represents the rotor position angle.

[0049] At this time, the stator flux vector ψ s The scalar form of can be expressed as:

[0050]

[0051] In the formula, ψ sα , sβ Respectively represent the magnitude of the stator flux mapped to the α and β axes; i d 、i q Represent the d-axis and q-axis currents respectively; ψ f Represents the modulus of the rotor permanent magnet excitation flux. By equivalently transforming the above formula, we can get:

[0052]

[0053] In the above formula, the stator flux on the left side of the equal sign can be obtained by integrating the back EMF of the motor port, and the coefficient on the right side of the equal sign is is the effective flux vector The modulus, as a scalar, reflects the effective magnetic flux size.

[0054] The effective flux vector is Its expression is Although its amplitude is similar to the rotor permanent magnet flux vector ψ r The amplitudes are different, but their directions are consistent, so the effective flux can be used to make an equivalent estimate of the rotor position.

[0055] In order to extract the effective magnetic flux of the motor through the back EMF, a first-order inertia filter is used to integrate the back EMF. The principle block diagram is as follows: Figure 1 As shown. The first-order inertial filter is composed of a high-pass filter connected in series with an integrator, and its transfer function can be expressed as

[0056]

[0057] In the formula, ω H Represents the cutoff frequency of the high-pass filter. S represents the complex frequency variable in the Laplace transform. G FOIF (s) represents the transfer function of the first-order inertial filter FOIF.

[0058] Compared with the pure integrator, the advantage of the first-order inertial filter is that the DC offset of the input back-EMF signal is suppressed by the front-end high-pass filter to avoid DC magnetic bias in the motor. However, ideally, the stator flux is obtained by integrating the back-EMF with a pure integrator. When the first-order inertial filter is used for integration, the obtained stator flux has amplitude attenuation and phase delay, which need to be compensated. The compensation amount of the stator flux amplitude and phase can be expressed as

[0059]

[0060] Where Amp com Represents the stator flux amplitude compensation, Pha com Represents the compensation amount of the stator flux phase, ω e Represents the rotor speed.

[0061] In step B), the effective flux signal is normalized, such as Figure 2 As shown. The principle of normalization is to first square the effective flux components of the α-axis and β-axis, take the sum and then take the square root, and finally get the amplitude of the effective flux vector. Then divide the effective flux components of the α-axis and β-axis by the amplitude of the effective flux vector, and then realize the normalization of the effective flux components of the α-axis and β-axis, and get the normalized flux phase information cosθ of the α-axis. re , and obtain the normalized flux phase information sinθ of the β axis re .

[0062] In step C), the feedforward estimated speed component is extracted based on the flux phase differential The principle block diagram is as follows Figure 3 The mathematical principle is to use the difference between the current sampled flux phase information and the last sampled flux phase information, and then divide it by the sampling time, that is, to differentiate the flux information to obtain the feedforward estimated speed component Right now

[0063]

[0064] In the formula, is the feedforward estimated speed component, and It represents the phase information of the effective flux method at the current moment (n) and the previous moment (n-1), and ΔT is the time interval between the two estimated moments.

[0065] In step D), the closed-loop estimated speed component is extracted based on the phase-locked loop The principle block diagram is as follows Figure 4 First, based on the concept of trigonometric function equivalent to infinitesimal, the position error signal is constructed. Its mathematical principle can be expressed as

[0066]

[0067] In the formula, Δθ e is the original position error, θ re is the real phase information of the effective flux, is the estimated phase information of the effective flux method, f(Δθ e ) is the original position error signal. The position error signal f(Δθ e ) is sent to PI regulation, and then appropriate filtering is added to obtain the closed-loop estimated speed component

[0068] In step E), the feedforward estimated speed component With closed loop estimated speed component Add and appropriately low-pass filter the result to get the final estimated speed

[0069]

[0070] In the formula, is the feedforward estimated speed component, is the closed-loop estimated speed component, is the estimated speed that will eventually participate in the speed closed-loop control. After integration, the estimated rotor position of the permanent magnet motor is obtained

[0071] Finally combined Figure 6 and Figure 7 The experimental waveforms further illustrate the control performance of the method.

[0072] Figure 6The figure shows the verification result of the present invention on a certain 80kW permanent magnet synchronous motor drive platform, and respectively shows the speed curve and DQ current when the motor is running with a speed ramp of 1000rpm / s. The experimental results show that when the motor is running, the estimated speed strictly tracks the actual speed without obvious error, the Q-axis current can be adjusted quickly, and the drive system has good dynamic performance.

[0073] Figure 7 The figure shows the verification result of the invention on the high-speed air compressor permanent magnet synchronous motor drive platform, and shows the speed curve and DQ current when the speed ramp used by the motor is 30000rpm / s. Figure 4 Similar to the experiment, when the motor is running, the estimated speed strictly tracks the actual speed, there is no obvious error in the estimated speed, and the q-axis current can be adjusted quickly, and the drive system has good dynamic performance.

[0074] These two test scenarios verified the effectiveness and reliability of the method of the present invention in different applications, and further demonstrated the engineering applicability of the technical solution and its superior dynamic adjustment capability.

[0075] Compiling the above method steps into a program and then storing it on a hard disk or other non-transitory storage medium constitutes an embodiment of "a non-transitory readable recording medium" of the present invention; and electrically connecting the storage medium to a computer processor and completing real-time estimation of the permanent magnet synchronous motor rotor position through data processing constitutes an embodiment of "a real-time estimation system for the permanent magnet synchronous motor rotor position" of the present invention.

[0076] It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computers, available storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer usable program codes.

[0077] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1A device that provides the functions specified in a block or multiple blocks.

[0078] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0079] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0080] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A real-time estimation method for the rotor position of a permanent magnet synchronous motor, characterized in that: The following steps are involved: The effective flux is extracted using the voltage and current signal data of the motor port, and normalized to obtain the effective flux phase information with unit amplitude and orthogonal phase. The effective flux phase of two adjacent samples is differentiated and then passed through a low-pass filter to obtain the feedforward estimated speed component. Construct a position error signal, send the position error signal to the phase-locked loop for proportional-integral closed-loop regulation, and obtain the closed-loop estimated speed component after low-pass filtering The feedforward estimated speed component With closed loop estimated speed component Add, low-pass filter the addition result to get the final estimated speed right After integration, the estimated rotor position of the permanent magnet motor is obtained 2. A method for real-time estimation of the rotor position of a permanent magnet synchronous motor according to claim 1, characterized in that: Extracting effective flux linkage includes integrating the back electromotive force using a first-order inertial filter and performing amplitude and phase compensation on the obtained stator flux linkage data.

3. A method for real-time estimation of the rotor position of a permanent magnet synchronous motor according to claim 2, characterized in that: The first-order inertial filter is composed of a high-pass filter connected in series with an integrator, and its transfer function is: In the formula, ω H represents the cutoff frequency of the high-pass filter, and S represents the complex frequency variable in the Laplace transform.

4. A method for real-time estimation of the rotor position of a permanent magnet synchronous motor according to claim 3, characterized in that: The calculation of the compensation amount in amplitude and phase compensation uses the following method: Where Amp com Represents the stator flux amplitude compensation, Pha com Represents the compensation amount of the stator flux phase, ω e Represents the rotor speed.

5. A method for real-time estimation of the rotor position of a permanent magnet synchronous motor according to claim 4, characterized in that: The normalization method is to first square the effective magnetic flux components of the α-axis and the β-axis respectively, take the sum and then take the square root to obtain the amplitude of the effective magnetic flux vector, and then divide the effective magnetic flux components of the α-axis and the β-axis by the amplitude of the effective magnetic flux vector respectively, so as to realize the normalization of the effective magnetic flux components of the α-axis and the β-axis, and obtain the normalized magnetic flux phase information of the α-axis and the normalized magnetic flux phase information of the β-axis.

6. A method for real-time estimation of the rotor position of a permanent magnet synchronous motor according to claim 5, characterized in that: Differentiation of the effective flux phase of two adjacent samples includes taking the difference between the current sampled flux phase information and the last sampled flux phase information, and then dividing it by the sampling time to obtain the feedforward estimated speed component. In the formula, is the feedforward estimated speed component, and It represents the phase of the effective flux method at the current time n and the previous time n-1, and ΔT is the time interval between the two estimated times.

7. A method for real-time estimation of the rotor position of a permanent magnet synchronous motor according to claim 6, characterized in that: The method of constructing the position error signal is as follows: According to the principle of heterodyne method, the position error signal In the formula, Δθ e is the original position error, θ re is the real phase information of the effective flux, is the estimated phase information of the effective flux linkage method.

8. A non-transitory readable recording medium for storing one or more programs including a plurality of instructions, characterized in that: When the instruction is executed, the processing circuit will be caused to execute a real-time estimation method for the rotor position of a permanent magnet synchronous motor according to any one of claims 1 to 7.

9. A real-time estimation system for the rotor position of a permanent magnet synchronous motor, comprising a processing circuit and a memory electrically coupled thereto, characterized in that: The memory configuration stores at least one program, wherein the program includes a plurality of instructions, and the processing circuit runs the program to execute a real-time estimation method for the rotor position of a permanent magnet synchronous motor according to any one of claims 1-7.

Images