A method, system and device for position-free closed-loop starting of a permanent magnet synchronous motor

Abstract

The present invention discloses a method, system, and device for position-free closed-loop starting of a permanent magnet synchronous motor. The method includes establishing a discretized dynamic model based on the permanent magnet synchronous motor's equations of motion and torque equations; solving the discretized dynamic model using the Runge-Kutta method to determine the variation patterns of the torque angle's fluctuation frequency and amplitude; calculating an adaptive compensation coefficient in real time based on the variation patterns of the fluctuation frequency and amplitude; calculating instantaneous active power in real time based on the voltage and current in a virtual coordinate system to extract the fluctuation amount of the instantaneous active power; automatically adjusting the adaptive compensation coefficient based on the given acceleration of a given current vector, and adjusting the given speed of the given current vector in real time based on the fluctuation amount of the instantaneous active power, so that the virtual coordinate system and the actual coordinate system can quickly converge to a synchronous state when the speed fluctuates. The present invention can fundamentally eliminate speed fluctuations in ultra-high-speed motors following acceleration changes during startup.

Description

Technical Field

[0001] The present invention relates to the field of motor drive control, and in particular to a position-free closed-loop starting method, system and equipment for a permanent magnet synchronous motor. Background Art

[0002] Ultra-high-speed permanent magnet motors, with their high power density, compactness, high transmission efficiency, high reliability, and fast dynamic response, have become the mainstream drive motors for centrifugal air compressors. Most centrifugal air compressors operate at speeds above 100,000 r / min, and it's difficult to find position sensors with an operating range of up to 2kHz. Therefore, positionless control has become the inevitable choice for achieving high-performance, high-speed permanent magnet motor drives. Given the lack of salient pole effects and low back-electromotive force amplitude at low speeds in high-speed motors, and particularly in centrifugal air compressor applications where a rapid takeoff to idle speed (around 30,000 r / min) within 1 second is crucial to extend the life of the air bearings, achieving rapid and stable startup of high-speed motors without positionless control is a current research priority and challenge both domestically and internationally.

[0003] The I / F starting strategy is widely used in the low-speed starting control of permanent magnet synchronous motors due to its advantages of simple structure and high stability. However, the traditional open-loop I / F starting control strategy has a disadvantage: the current amplitude and frequency cannot be automatically adjusted, resulting in large fluctuations in the actual output torque, actual acceleration, and actual speed of the motor during the dynamic process; especially in the application scenario of centrifugal air compressors, after the motor is started, it must quickly accelerate to the idle state. The angle fluctuation during the acceleration mutation process can easily cause the current to not track and the motor to lose control, and it is impossible to fundamentally eliminate the speed fluctuation of ultra-high-speed motors after the acceleration changes during the starting process. Summary of the Invention

[0004] The purpose of the present invention is to provide a method, system and device for position-free closed-loop starting of a permanent magnet synchronous motor, so as to solve the problem that the speed fluctuation after the acceleration change of the ultra-high-speed motor during the starting process cannot be fundamentally eliminated.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] A method for starting a permanent magnet synchronous motor without position and in a closed loop, comprising:

[0007] Assume that the axis system where the given current vector of the permanent magnet synchronous motor is located is a virtual coordinate system, and the synchronous rotating coordinate system of the permanent magnet synchronous motor is a real coordinate system;

[0008] A discretized dynamic model is established according to the motion equation and torque equation of the permanent magnet synchronous motor; the discretized dynamic model is a differential equation group of the dynamic motion model of the permanent magnet synchronous motor under I / F control;

[0009] Solving the discretized dynamic model based on the Runge-Kutta method to determine the variation pattern of the torque angle fluctuation frequency and fluctuation amplitude;

[0010] Calculating the adaptive filter cutoff frequency and the adaptive compensation coefficient of the given current vector in real time according to the variation law of the fluctuation frequency and the fluctuation amplitude;

[0011] Calculating instantaneous active power in real time based on the voltage and current in the virtual coordinate system, and extracting the fluctuation of the instantaneous active power through an adaptive filter;

[0012] The adaptive compensation coefficient is automatically adjusted according to the given acceleration of the given current vector, and the given speed of the given current vector is adjusted in real time based on the fluctuation of the instantaneous active power, so that the virtual coordinate system and the actual coordinate system can quickly converge to a synchronous state when the speed fluctuates.

[0013] Optionally, the discretized dynamic model is:

[0014] Among them, ω i is the rotating mechanical angular velocity of the given current vector; ω r is the actual mechanical angular velocity of the rotor, n p is the number of rotor pole pairs; ψ r is the permanent magnet flux amplitude; i s is a given current vector; θ is a torque angle, which is the angle between the quadrature axis in the virtual coordinate system and the direct axis in the actual coordinate system; J is the moment of inertia of the motor rotor; B is the viscous friction coefficient of the motor; T L is the load torque.

[0015] Optionally, solving the discretized dynamic model based on the Runge-Kutta method to determine the variation pattern of the fluctuation frequency and fluctuation amplitude of the torque angle specifically includes:

[0016] The discretized dynamic model is approximated in four steps using the Runge-Kutta method, and the variation law of the fluctuation frequency and the fluctuation amplitude of the torque angle is solved offline using MATLAB software according to the initial state and stable conditions under I / F startup; the variation law of the fluctuation frequency and the fluctuation amplitude is that when the fluctuation frequency of the torque angle increases with the moment of inertia, the given current acceleration, the viscosity coefficient and the actual rotating mechanical angular velocity of the rotor, the fluctuation frequency of the torque angle approximately decays linearly, and the fluctuation amplitude of the torque angle increases linearly with the increase of the moment of inertia and the given acceleration, but decreases with the increase of the viscosity coefficient.

[0017] Optionally, calculating the adaptive filter cutoff frequency and the adaptive compensation coefficient of the given current vector in real time according to the variation law of the fluctuation frequency and the fluctuation amplitude specifically includes:

[0018] Based on the offline numerical solution to solve the changing laws of the fluctuation frequency and amplitude, combined with the given acceleration of the given current vector and the given speed of the permanent magnet synchronous motor during the I / F starting process, the adaptive filter cutoff frequency and the adaptive compensation coefficient of the given current vector are calculated in real time under I / F closed-loop control.

[0019] Optionally, the instantaneous active power is calculated in real time according to the voltage and current in the virtual coordinate system, and the fluctuation of the instantaneous active power is extracted by an adaptive filter, specifically including:

[0020] Obtain the stator voltage model of the permanent magnet synchronous motor;

[0021] Decomposing the stator voltage model along the direct axis and the quadrature axis in the virtual coordinate system to obtain a voltage equation in the virtual coordinate system, and determining an instantaneous active power model according to the voltage equation in the virtual coordinate system and a given current amplitude based on an active power calculation formula;

[0022] Based on the instantaneous active power model, the fluctuation amount of the instantaneous active power is extracted through an adaptive filter according to the adaptive compensation coefficient.

[0023] Optionally, the permanent magnet synchronous motor is a surface-mounted permanent magnet synchronous motor.

[0024] A position-free closed-loop starting system for a permanent magnet synchronous motor, comprising:

[0025] A coordinate system determination module, configured to set the axis system where the given current vector of the permanent magnet synchronous motor is located as a virtual coordinate system, and the synchronous rotating coordinate system of the permanent magnet synchronous motor as an actual coordinate system;

[0026] A discretized dynamic model establishment module is used to establish a discretized dynamic model based on the motion equation and torque equation of the permanent magnet synchronous motor; the discretized dynamic model is a set of differential equations of the dynamic motion model of the permanent magnet synchronous motor under I / F control;

[0027] a variation law determination module, configured to solve the discretized dynamic model based on the Runge-Kutta method to determine the variation law of the fluctuation frequency and amplitude of the torque angle;

[0028] An adaptive compensation coefficient determination module, configured to calculate in real time the adaptive filter cutoff frequency and the adaptive compensation coefficient of a given current vector according to the variation rules of the fluctuation frequency and the fluctuation amplitude;

[0029] An instantaneous active power fluctuation extraction module is used to calculate the instantaneous active power in real time based on the voltage and current in the virtual coordinate system, and extract the instantaneous active power fluctuation through an adaptive filter;

[0030] A speed fluctuation adjustment module is configured to automatically adjust the adaptive compensation coefficient according to the given acceleration of the given current vector, and to adjust the given speed of the given current vector in real time based on the fluctuation amount of the instantaneous active power, so that the virtual coordinate system and the actual coordinate system can quickly converge to a synchronous state when the speed fluctuates.

[0031] Optionally, the discretized dynamic model is:

[0032] Among them, ω i is the rotating mechanical angular velocity of the given current vector; ω r is the actual mechanical angular velocity of the rotor, n p is the number of rotor pole pairs; ψ r is the permanent magnet flux amplitude; i s is a given current vector; θ is a torque angle, which is the angle between the quadrature axis in the virtual coordinate system and the direct axis in the actual coordinate system; J is the moment of inertia of the motor rotor; B is the viscous friction coefficient of the motor; T L is the load torque.

[0033] An electronic device includes a memory and a processor, wherein the memory is used to store a computer program, and the processor runs the computer program to enable the electronic device to execute the above-mentioned permanent magnet synchronous motor position-free closed-loop starting method.

[0034] A computer-readable storage medium stores a computer program, which, when executed by a processor, implements the above-mentioned position-free closed-loop starting method for a permanent magnet synchronous motor.

[0035] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects: the present invention provides a positionless closed-loop starting method, system and equipment for a permanent magnet synchronous motor, which sets a virtual coordinate system and uses the fluctuation of the instantaneous active power of the motor to adjust the given speed of a given current vector in real time, thereby increasing the virtual damping torque component to reduce the fluctuation of the torque angle, so that when the speed fluctuates, the virtual coordinate system and the actual coordinate system can quickly converge to a synchronous state, thereby fundamentally eliminating the speed fluctuation of the ultra-high-speed motor after the acceleration changes during the startup process. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0037] Figure 1 The spatial vector diagram before and after the I / F control in the present invention is started; Figure 1 (a) is a spatial vector diagram before the I / F control provided by the present invention is started; Figure 1 (b) is a spatial vector diagram after the I / F control provided by the present invention is started;

[0038] Figure 2 This is a flow chart of the position-free closed-loop starting method for a permanent magnet synchronous motor provided by the present invention;

[0039] Figure 3 It is the spatial vector diagram of the I / F starting acceleration process in the dual coordinate system of the present invention; Figure 3 (a) is the time diagram of t=t1 during the I / F starting acceleration process; Figure 3 (b) is the time diagram of t=t2 during the I / F starting acceleration process; Figure 3 (c) is the time diagram of t=t3 during the I / F starting acceleration process; Figure 3 (d) is the time diagram of t=t4 during the I / F starting acceleration process;

[0040] Figure 4 This is a schematic diagram of the position-free closed-loop starting method for a permanent magnet synchronous motor provided by the present invention;

[0041] Figure 5 A comparison diagram of the motor torque angle and speed fluctuation before and after using the position-free closed-loop starting method for a permanent magnet synchronous motor provided by the present invention; Figure 5 (a) shows the speed tracking and torque angle waveforms under open-loop I / F control under sudden acceleration; Figure 5 (b) is the waveform of speed tracking and torque angle under adaptive given current vector closed-loop I / F control. DETAILED DESCRIPTION

[0042] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0043] The purpose of the present invention is to provide a method, system and device for position-free closed-loop starting of a permanent magnet synchronous motor, which can fundamentally eliminate the speed fluctuation of an ultra-high-speed motor after acceleration changes during the starting process.

[0044] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0045] The principle of the open-loop I / F startup strategy is as follows:

[0046] The basic control mode of I / F startup is to give a rotating target given current vector in the synchronous rotating coordinate system of the motor. The amplitude of the given current vector is a constant value, and the rotation speed of the given current vector is the I / F control given speed. The present invention introduces a virtual given current vector d v -q v Coordinate system. Figure 1 As shown, take d v Axis is the direct axis in the virtual coordinate system, q v The d axis is the direct axis in the actual coordinate system, and the q axis is the cross axis. v Axis direction and given current vector i s Keep the direction consistent. v The angle between the axis and the d axis is the actual torque angle θ. v -q v i in the coordinate system s Projected into the dq coordinate system, they are represented as i d and i q .

[0047] like Figure 1 As shown in (a), at the moment of I / F startup, the torque angle θ is 0, and the actual dq coordinate system is larger than the virtual

[0048] Given current vector d v -q v The coordinate system is advanced by 90°, and the given current vector i s Acting on the d-axis of the actual coordinate system, no torque is generated. Figure 1 As shown in (b), after the ramp speed command is given, d v -q v The coordinate system will accelerate to catch up with the actual dq coordinate system, the angle θ will become larger, and the given current vector i s Acting on the actual q-axis current i s Sinθ will increase accordingly with the increase of angle θ. When the electromagnetic torque generated by the actual q-axis current is greater than the load torque, the actual rotor will start to rotate.

[0049] The research object of this invention is ultra-high-speed permanent magnet synchronous motor. Figure 1 , d v -q v The stator voltage equation in the virtual coordinate system can be expressed as:

[0050]

[0051] where u sd v and u sq v is the virtual coordinate system d v axis and q v Shaft voltage, R s is the stator resistance, L s is the stator inductance, ψ r is the permanent magnet flux amplitude, ω i is the rotating mechanical angular velocity of a given current vector, ω r is the actual mechanical angular velocity of the rotor, n p is the number of rotor pole pairs.

[0052] Figure 2 The flow chart of the position-free closed-loop starting method of the permanent magnet synchronous motor provided by the present invention is as follows: Figure 2 As shown, the present invention provides a position-free closed-loop starting method for a permanent magnet synchronous motor, comprising:

[0053] Step 201: Assume that the axis system where the given current vector of the permanent magnet synchronous motor is located is a virtual coordinate system, and the synchronous rotating coordinate system of the permanent magnet synchronous motor is an actual coordinate system.

[0054] Step 202: establishing a discretized dynamic model according to the motion equation and torque equation of the permanent magnet synchronous motor; the discretized dynamic model is a differential equation group of the dynamic motion model of the permanent magnet synchronous motor under I / F control.

[0055] As an optional embodiment of the present invention, the torque equation is: The equation of motion is T e is the electromagnetic torque of the motor, J is the moment of inertia of the motor rotor; B is the viscous friction factor of the motor; T L is the load torque.

[0056] The discretized dynamic model is:

[0057] Step 203: Solve the discretized dynamic model based on the Runge-Kutta method to determine the variation pattern of the fluctuation frequency and fluctuation amplitude of the torque angle.

[0058] The step 203 specifically includes: using the Runge-Kutta method to perform a four-step segmented approximation on the discretized dynamic model, and using MATLAB software to solve the variation law of the fluctuation frequency and the fluctuation amplitude of the torque angle offline according to the initial state and stable conditions under I / F startup; the variation law of the fluctuation frequency and the fluctuation amplitude is that when the fluctuation frequency of the torque angle increases with the moment of inertia, the current given acceleration, the viscosity coefficient and the actual rotating mechanical angular velocity of the rotor, the fluctuation frequency of the torque angle approximately linearly attenuates, and the fluctuation amplitude of the torque angle linearly increases with the increase of the moment of inertia and the given acceleration but decreases with the increase of the viscosity coefficient.

[0059] As an optional embodiment of the present invention, the motion equation and torque equation of the motor are combined to obtain a group of differential equations of the dynamic motion model of the motor under I / F control; the differential equations of the dynamic motion model are numerically solved according to the Runge-Kutta method to obtain the torque angle θ and the actual mechanical angular velocity ω of the rotor. r , the actual mechanical angular acceleration of the rotor K ar The changing rules of the motor mechanical parameters and the given current vector.

[0060] As an optional embodiment of the present invention, according to formula (2), it can be seen that under open-loop I / F control, the actual torque angle of the motor is not only affected by the motor mechanical parameters B, J, T L and the given current vector i s The influence of the actual mechanical angular velocity ω of the rotor will also r In order to study the changing characteristics of various parameters in the motor operation process under I / F control, the present invention adopts the numerical solution method to analyze the torque angle change, the actual motor speed, and the actual acceleration tracking characteristics in the dual coordinate system, and divides its startup acceleration into three stages, such as Figure 3 As shown, it can be seen that:

[0061] The first stage: During the process of t1-t2, Figure 3 (c) The actual motor speed is always less than the open loop speed

[0062] At a constant speed, the speed error increases in the negative direction and reaches the maximum error at time t2; Figure 3 (a) The torque angle is increasing; Figure 3 (b) The actual acceleration of the rotor also increases slowly from 0 and reaches the fixed acceleration given by the open loop at time t2.

[0063] The second stage: During t2-t3, Figure 3 (c) The actual motor speed is always less than the open loop speed

[0064] The speed is constant, but the speed error is decreasing. At time t3, the motor speed error is 0. Figure 3 (a) The torque angle continues to increase, Figure 3 (b) The actual rotor acceleration continues to increase, and at time t3 both the torque angle and the actual rotor acceleration reach their maximum values.

[0065] The third stage: During the t3-t4 period, Figure 3 (c) The actual motor speed is always greater than the open loop speed

[0066] At a fixed speed, the speed error is always greater than 0. Figure 3 In (c), the torque angle is decreasing. Figure 3 (d) The actual rotor acceleration is also decreasing. At time t4, the torque angle is at its minimum value, close to 0. At this time, the actual speed is the same as the open-loop set speed, and the actual speed error is 0. At this time, the actual speed acceleration reaches its minimum value, close to 0, and the acceleration error reaches its positive maximum value.

[0067] Based on the fourth-order Runge-Kutta method, the numerical solution of the equation can be obtained, and the torque angle fluctuation frequency can be obtained as the moment of inertia J and the current given acceleration K. ai , viscosity coefficient B, speed ω r As increases, the torque angle fluctuation frequency is approximately linearly attenuated, and the torque angle fluctuation amplitude increases linearly with the increase of the moment of inertia and the given acceleration, but decreases with the increase of B.

[0068] According to the numerical solution results, we can get the following rules, where f wave (Δθ) represents the torque angle fluctuation frequency, and Max(Δθ) represents the torque angle fluctuation amplitude.

[0069]

[0070] Step 204: Calculate the adaptive filter cutoff frequency and the adaptive compensation coefficient of the given current vector in real time according to the variation rule of the fluctuation frequency and the fluctuation amplitude.

[0071] Step 204 specifically includes: solving the variation pattern of the fluctuation frequency and the fluctuation amplitude based on an offline numerical solution, and combining the given acceleration and the given speed of the given current vector of the permanent magnet synchronous motor during the I / F starting process to obtain the adaptive filter cutoff frequency and the adaptive compensation coefficient of the given current vector for real-time calculation under the I / F closed-loop control.

[0072] Step 205: Calculate the instantaneous active power in real time based on the voltage and current in the virtual coordinate system, and extract the fluctuation of the instantaneous active power through an adaptive filter.

[0073] The step 205 specifically includes: obtaining a stator voltage model of the permanent magnet synchronous motor; decomposing the stator voltage model along the direct axis and the quadrature axis in the virtual coordinate system to obtain a voltage equation in the virtual coordinate system; based on the active power calculation formula, determining the instantaneous active power model according to the voltage equation in the virtual coordinate system and a given current amplitude; based on the instantaneous active power model, extracting the fluctuation amount of the instantaneous active power through an adaptive filter according to the adaptive compensation coefficient.

[0074] As an optional embodiment of the present invention, according to the electromagnetic torque of the motor, the change in the electromagnetic torque of the motor within the time Δt with respect to the torque angle θ near the steady-state angle θ0 is:

[0075]

[0076] According to formula 2 and formula 4, we can get:

[0077]

[0078] In order to achieve closed-loop control of the actual speed and the motor's given current vector angular velocity tracking, it can be seen from Equation 5 that ΔT e The torque angle change Δθ and the given speed fluctuation Δω i Related, in order to adjust ΔT e You need to adjust ω i , considering the set speed ω at a given current vector i The present invention sets the compensation term Δω i :

[0079]

[0080] Among them, k ω is the adaptive adjustment coefficient.

[0081] Combine Figure 1 The vector diagram under I / F open-loop control can be obtained according to the active power calculation formula:

[0082]

[0083] Where P is the active power of the motor, U is the voltage vector amplitude in the actual coordinate system, I s For a given current vector magnitude i s , The motor voltage in the actual coordinate system and the current vector i in the virtual coordinate system are given s The angle between , according to the vector diagram:

[0084]

[0085] When the given current is stable, Δω r Voltage can be used The instantaneous change is reflected, and because the given current vector amplitude is constant, at the steady-state operating point, Δω r and P / i s It can be approximately regarded as a proportional relationship and can be expressed as:

[0086]

[0087] Among them, Δω r is the given current vector given speed compensation obtained according to active power adaptive filtering, ΔU is the change in the voltage vector amplitude in the actual coordinate system, and ΔP is the change in the active power of the motor.

[0088] Step 206: Automatically adjust the adaptive compensation coefficient according to the given acceleration of the given current vector, and adjust the given speed of the given current vector in real time based on the fluctuation of the instantaneous active power, so that the virtual coordinate system and the actual coordinate system can quickly converge to a synchronous state when the speed fluctuates.

[0089] As an optional embodiment of the present invention, the active power of the motor during normal operation is a component that increases with the increase of the speed, wherein the change of the active power can be approximated by the adaptive filter to obtain its change rate, so according to the virtual d v -q v The voltage equation in the coordinate system can be obtained:

[0090]

[0091] According to equations 9 and 10, the increment of closed-loop regulation Δω can be obtained i for:

[0092]

[0093] Where T p is the time constant of the adaptive filter. Based on the numerical solution, the present invention designs the time constant of the filter according to Equation 11, taking into account factors such as the given current vector amplitude, given acceleration, and motor mechanical parameters, and obtains:

[0094] T p =k f ·f wave (Δθ) (12)

[0095] where k f is the adaptive filter adjustment coefficient, and its value can be selected based on Max(Δθ) obtained by numerical solution analysis.

[0096] I / F closed loop given speed with given current vector adaptive regulation of the present invention

[0097]

[0098] Among them, s is the Laplace operator.

[0099] As an optional implementation manner of the present invention, the permanent magnet synchronous motor is a surface-mounted permanent magnet synchronous motor.

[0100] Figure 4 The schematic diagram of the position-free closed-loop starting method of the permanent magnet synchronous motor provided by the present invention is as follows: Figure 4 As shown, where u α is the voltage of the α axis in vector control, u β is the voltage of the β-axis in vector control, and θe is the electrical angle of the motor in vector control.

[0101] A simulation model was built in MATLAB / Simulink to verify the feasibility of the algorithm. The comparison of the motor speed and torque angle waveforms before and after the given current vector adaptive adjustment was obtained as shown in the following figure: Figure 5 shown by Figure 5 It can be seen that in the basic I / F control method without adaptive adjustment of the given current vector, the torque angle θ fluctuation amplitude changes from 70° to 100° at the acceleration mutation point, which exceeds the range of stable operation. The motor system may lose step at any time, the control performance is poor, and the control system reliability is low; after adaptive adjustment of the given current vector, the speed fluctuation at the switching moment can be quickly reduced, the speed overshoot is small, the torque angle fluctuation amplitude after the acceleration mutation is reduced from 100° to 45°, and it quickly converges to a new stable value within 0.5s; the given current vector adaptive adjustment method proposed in the present invention significantly reduces the torque angle fluctuation during the motor I / F fixed acceleration starting and variable acceleration starting, and the motor speed can also quickly converge to a steady state, thereby enhancing the reliability of the ultra-high-speed motor starting system and effectively improving the control performance of the I / F starting strategy.

[0102] This invention adjusts the given current vector and speed through instantaneous active power feedback from the motor. During motor acceleration, a high-frequency virtual damping torque component is added to the load torque, reducing torque angle fluctuations and enabling the motor speed to quickly track to the given speed. This system offers excellent performance during both open-loop fixed acceleration and variable acceleration starting of the motor, providing important guidance for position-free low-speed control of permanent magnet synchronous motors and the design of maximum acceleration starting systems for ultra-high-speed air compressor applications.

[0103] Example 2

[0104] In order to execute the method corresponding to the above-mentioned embodiment 1 and achieve the corresponding functions and technical effects, a position-free closed-loop starting system for a permanent magnet synchronous motor is provided below.

[0105] A position-free closed-loop starting system for a permanent magnet synchronous motor, comprising:

[0106] The coordinate system determination module is used to set the axis system where the given current vector of the permanent magnet synchronous motor is located as a virtual coordinate system, and the synchronous rotating coordinate system of the permanent magnet synchronous motor as an actual coordinate system.

[0107] A discretized dynamic model establishment module is used to establish a discretized dynamic model based on the motion equation and torque equation of the permanent magnet synchronous motor; the discretized dynamic model is a set of differential equations of the dynamic motion model of the permanent magnet synchronous motor under I / F control; the discretized dynamic model is:

[0108] Among them, ω i is the rotating mechanical angular velocity of the given current vector; ω r is the actual mechanical angular velocity of the rotor, n p is the number of rotor pole pairs; ψ r is the permanent magnet flux amplitude; i s is a given current vector; θ is a torque angle, which is the angle between the quadrature axis in the virtual coordinate system and the direct axis in the actual coordinate system; J is the moment of inertia of the motor rotor; B is the viscous friction coefficient of the motor; T L is the load torque.

[0109] The variation law determination module is used to solve the discretized dynamic model based on the Runge-Kutta method to determine the variation law of the fluctuation frequency and fluctuation amplitude of the torque angle.

[0110] The adaptive compensation coefficient determination module is used to calculate the adaptive filter cutoff frequency and the adaptive compensation coefficient of the given current vector in real time according to the change law of the fluctuation frequency and the fluctuation amplitude.

[0111] The instantaneous active power fluctuation extraction module is used to calculate the instantaneous active power in real time according to the voltage and current in the virtual coordinate system, and extract the instantaneous active power fluctuation through an adaptive filter.

[0112] A speed fluctuation adjustment module is configured to automatically adjust the adaptive compensation coefficient according to the given acceleration of the given current vector, and to adjust the given speed of the given current vector in real time based on the fluctuation amount of the instantaneous active power, so that the virtual coordinate system and the actual coordinate system can quickly converge to a synchronous state when the speed fluctuates.

[0113] The system of the present invention adjusts the given current vector and speed through instantaneous active power feedback from the motor. During motor acceleration, a high-frequency virtual damping torque component is added to the load torque, reducing torque angle fluctuations and enabling the motor speed to quickly track the given speed. It exhibits excellent performance during both open-loop fixed acceleration and variable acceleration starting of the motor, providing important guidance for position-free low-speed control of permanent magnet synchronous motors and the design of maximum acceleration starting systems for ultra-high-speed air compressor applications.

[0114] Example 3

[0115] The present invention also provides another position-free closed-loop starting system for a permanent magnet synchronous motor, comprising the following modules:

[0116] The torque angle fluctuation law acquisition module is used to design the adaptive adjustment parameters of a given current vector.

[0117] The real-time active power fluctuation acquisition module is used to observe the fluctuation of the motor active power during the I / F starting acceleration process in real time according to the given current vector adaptive regulator parameter design rules.

[0118] The speed fluctuation regulation module is used to build a feedback regulation algorithm based on the active power fluctuation, automatically adjust the compensation parameters according to the given acceleration of the given current vector, and adjust the given speed of the given current vector in real time based on the power fluctuation, so that the virtual coordinate system and the actual coordinate system can quickly converge to a synchronous state when the speed fluctuates.

[0119] On the basis of the above technical solution, the system of the present invention can also be improved as follows:

[0120] Assume that the axis system where the given current vector of the motor is located is d v -q v Virtual coordinate system, the synchronous rotating coordinate system of the motor is the dq actual coordinate system.

[0121] As an optional embodiment of the present invention, the torque angle fluctuation law acquisition module is specifically used to, according to the established d v -q v In the virtual coordinate system, the angle between the given current vector and the actual rotation d-axis of the motor during the I / F startup process is calculated as the torque angle θ.

[0122] According to the motion equation and torque equation of the motor, the differential equation group of the dynamic motion model of the motor under I / F control is obtained.

[0123] The differential equations are numerically solved according to the Runge-Kutta method, and the motion laws of the three different stages of the I / F startup acceleration process are obtained.

[0124] According to the numerical solution of Runge-Kutta method, the torque angle θ and the actual mechanical angular velocity ω of the rotor are obtained. r , the actual mechanical angular acceleration of the rotor K ar The law of change of given current vector and motor mechanical parameters.

[0125] According to the numerical solution results of the Runge-Kutta method, the influence rules of the fluctuation frequency and amplitude of the motor torque angle during the I / F starting acceleration process are obtained.

[0126] As an optional embodiment of the present invention, the real-time active power fluctuation acquisition module is specifically used to convert the stator voltage model of the motor along d v -q v d in the virtual coordinate system v axis and q v Axis decomposition, get the voltage equation in the virtual coordinate system, according to the active power calculation formula, multiply the voltage equation by the given current amplitude i s , and obtain the instantaneous active power model.

[0127] Based on the offline numerical solution, the changing laws of the fluctuation frequency and amplitude are solved. Combined with the variables such as the given current vector, given acceleration and given speed of the motor during the I / F starting process, the given current vector adaptive filter parameters and adaptive compensation coefficient under I / F closed-loop control are obtained.

[0128] According to the changing rules of the torque angle fluctuation frequency and amplitude, the real-time adaptive filter parameters are obtained by combining the motor mechanical parameters and the given current vector to obtain the fluctuation amount of the instantaneous active power.

[0129] The present invention combines the Runge-Kutta method to numerically solve the motor's equations of motion and torque equations, obtaining the motor speed, the fluctuation frequency of the actual rotor acceleration, the motor's mechanical parameters, and the variation pattern of the given current vector. The instantaneous active power is then calculated in real time based on the voltage and current in the virtual coordinate system. The adaptive filter cutoff frequency is then calculated in real time based on the variation pattern. A feedback control algorithm is constructed based on the power fluctuations to online adjust the speed of the given current vector under I / F control. By adding a virtual damping torque component to the given current vector's given speed, the virtual coordinate system and the actual coordinate system can quickly converge to a synchronized state when the speed fluctuates. Furthermore, the filter parameters can be automatically adjusted when the open-loop acceleration continuously changes, accelerating the torque angle convergence rate and enhancing the system's stability and adaptability.

[0130] Example 4

[0131] An embodiment of the present invention provides an electronic device including a memory and a processor, wherein the memory is used to store a computer program, and the processor runs the computer program to enable the electronic device to execute the position-free closed-loop starting method of a permanent magnet synchronous motor provided in the first embodiment.

[0132] In practical applications, the above-mentioned electronic device may be a server.

[0133] In practical applications, an electronic device includes at least one processor, a memory, a bus, and a communication interface.

[0134] Wherein: the processor, the communication interface, and the memory communicate with each other via a communication bus.

[0135] Communication interface, used to communicate with other devices.

[0136] The processor is used to execute the program, and specifically can execute the method described in the above embodiment.

[0137] Specifically, the program may include program codes including computer operation instructions.

[0138] The processor may be a central processing unit (CPU), an application-specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of the present invention. The one or more processors included in the electronic device may be processors of the same type, such as one or more CPUs, or processors of different types, such as one or more CPUs and one or more ASICs.

[0139] Memory is used to store programs. The memory may include high-speed RAM memory, and may also include non-volatile memory (non-volatile memory), such as at least one disk storage.

[0140] Based on the description of the above embodiments, the present invention provides a storage medium on which computer program instructions are stored. The computer program instructions can be executed by a processor to implement the method described in any embodiment.

[0141] The permanent magnet synchronous motor position-free closed-loop starting system provided in the embodiments of the present application exists in various forms, including but not limited to:

[0142] (1) Mobile communication devices: These devices are characterized by their mobile communication capabilities and are primarily designed to provide voice and data communications. These terminals include smartphones (e.g., iPhones), multimedia phones, feature phones, and low-end phones.

[0143] (2) Ultra-mobile personal computer devices: These devices fall under the category of personal computers, have computing and processing capabilities, and generally also have mobile Internet access capabilities. These terminals include PDAs, MIDs, and UMPC devices, such as the iPad.

[0144] (3) Portable entertainment devices: These devices can display and play multimedia content. These devices include audio and video players (such as iPods), handheld game consoles, e-books, smart toys, and portable car navigation devices.

[0145] (4) Other electronic devices with data interaction functions.

[0146] Thus far, specific embodiments of the present subject matter have been described. Other embodiments are within the scope of the appended claims. In some cases, the actions recited in the claims can be performed in a different order and still achieve the desired results. Furthermore, the processes depicted in the accompanying drawings do not necessarily require the specific order shown or sequential order to achieve the desired results. In certain embodiments, multitasking and parallel processing may be advantageous.

[0147] The systems, devices, modules, or units described in the above embodiments may be implemented by computer chips or entities, or by products having certain functions. A typical implementation device is a computer. Specifically, the computer may be, for example, a personal computer, a laptop computer, a cellular phone, a camera phone, a smartphone, a personal digital assistant, a media player, a navigation device, an email device, a game console, a tablet computer, a wearable device, or a combination of any of these devices.

[0148] For the convenience of description, the above devices are described in terms of their functions and are divided into various units and described separately. Of course, when implementing the present application, the functions of each unit can be implemented in the same one or more software and / or hardware. It should be understood by those skilled in the art that the embodiments of the present application can be provided as methods, systems or computer program products. Therefore, the present application can take the form of a complete hardware embodiment, a complete software embodiment or an embodiment combining software and hardware. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0149] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems) and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes 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 1 A device that provides the functions specified in a block or multiple blocks.

[0150] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work 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 The function specified in one or more boxes.

[0151] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0152] In a typical configuration, a computing device includes one or more processors (CPUs), input / output interfaces, network interfaces, and memory.

[0153] Memory may include non-permanent storage in a computer-readable medium, random access memory (RAM) and / or non-volatile memory in the form of read-only memory (ROM) or flash RAM. Memory is an example of a computer-readable medium.

[0154] Computer-readable media include permanent and non-permanent, removable and non-removable media that can be implemented by any method or technology to store information. The information can be computer-readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disc read-only memory (CD-ROM),

[0155] Digital versatile discs (DVDs) or other optical storage, magnetic cassettes, magnetic tape, disk storage or other magnetic storage devices

[0156] Or any other non-transmission medium that can be used to store information that can be accessed by a computing device. According to the definition in this article, computer-readable media does not include temporary computer-readable media (transitory media), such as modulated data signals and carrier waves.

[0157] It should also be noted that the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, commodity, or apparatus that includes a series of elements includes not only those elements but also other elements not explicitly listed, or includes elements inherent to such process, method, commodity, or apparatus. In the absence of further limitations, an element defined by the phrase "comprises a ..." does not exclude the presence of other identical elements in the process, method, commodity, or apparatus that includes the element.

[0158] The present application may be described in the general context of computer-executable instructions executed by a computer, such as program modules. Generally, program modules include routines, programs, objects, components, data structures, and the like that perform specific tasks or implement specific abstract data types. The present application may also be practiced in distributed computing environments where tasks are performed by remote processing devices connected via a communications network. In a distributed computing environment, program modules may be located in local and remote computer storage media, including storage devices.

[0159] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Reference can be made to the common and similar parts between the various embodiments. For the systems disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the method description.

[0160] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims

1. A method for starting a permanent magnet synchronous motor without position and in a closed loop, characterized in that: include: Assume that the axis system where the given current vector of the permanent magnet synchronous motor is located is a virtual coordinate system, and the synchronous rotating coordinate system of the permanent magnet synchronous motor is a real coordinate system; A discretized dynamic model is established according to the motion equation and torque equation of the permanent magnet synchronous motor; the discretized dynamic model is a differential equation group of the dynamic motion model of the permanent magnet synchronous motor under I / F control; Solving the discretized dynamic model based on the Runge-Kutta method to determine the variation pattern of the torque angle fluctuation frequency and fluctuation amplitude; Calculating the adaptive filter cutoff frequency and the adaptive compensation coefficient of the given current vector in real time according to the variation law of the fluctuation frequency and the fluctuation amplitude; Calculating instantaneous active power in real time based on the voltage and current in the virtual coordinate system, and extracting the fluctuation of the instantaneous active power through an adaptive filter; The adaptive compensation coefficient is automatically adjusted according to the given acceleration of the given current vector, and the given speed of the given current vector is adjusted in real time based on the fluctuation of the instantaneous active power, so that the virtual coordinate system and the actual coordinate system can quickly converge to a synchronous state when the speed fluctuates.

2. The method for starting a permanent magnet synchronous motor without position closed loop according to claim 1, characterized in that: The discretized dynamic model is: Among them, ω i is the rotating mechanical angular velocity of the given current vector; ω r is the actual mechanical angular velocity of the rotor, n p is the number of rotor pole pairs; ψ r is the permanent magnet flux amplitude; i s is a given current vector; θ is a torque angle, which is the angle between the quadrature axis in the virtual coordinate system and the direct axis in the actual coordinate system; J is the moment of inertia of the motor rotor; B is the viscous friction coefficient of the motor; T L is the load torque.

3. The method for starting a permanent magnet synchronous motor without position closed loop according to claim 1, characterized in that: The discretized dynamic model is solved based on the Runge-Kutta method to determine the variation pattern of the fluctuation frequency and amplitude of the torque angle, specifically including: The discretized dynamic model is approximated in four steps using the Runge-Kutta method, and the variation law of the fluctuation frequency and the fluctuation amplitude of the torque angle is solved offline using MATLAB software according to the initial state and stable conditions under I / F startup; the variation law of the fluctuation frequency and the fluctuation amplitude is that when the fluctuation frequency of the torque angle increases with the moment of inertia, the given current acceleration, the viscosity coefficient and the actual rotating mechanical angular velocity of the rotor, the fluctuation frequency of the torque angle approximately decays linearly, and the fluctuation amplitude of the torque angle increases linearly with the increase of the moment of inertia and the given acceleration, but decreases with the increase of the viscosity coefficient.

4. The method for starting a permanent magnet synchronous motor without position closed loop according to claim 1, characterized in that: The adaptive filter cutoff frequency and the adaptive compensation coefficient of the given current vector are calculated in real time according to the variation law of the fluctuation frequency and the fluctuation amplitude, specifically including: Based on the offline numerical solution to solve the changing laws of the fluctuation frequency and amplitude, combined with the given acceleration of the given current vector and the given speed of the permanent magnet synchronous motor during the I / F starting process, the adaptive filter cutoff frequency and the adaptive compensation coefficient of the given current vector are calculated in real time under I / F closed-loop control.

5. The position-free closed-loop starting method of a permanent magnet synchronous motor according to claim 1, characterized in that: The instantaneous active power is calculated in real time according to the voltage and current in the virtual coordinate system, and the fluctuation of the instantaneous active power is extracted by an adaptive filter, specifically including: Obtain the stator voltage model of the permanent magnet synchronous motor; Decomposing the stator voltage model along the direct axis and the quadrature axis in the virtual coordinate system to obtain a voltage equation in the virtual coordinate system, and determining an instantaneous active power model according to the voltage equation in the virtual coordinate system and a given current amplitude based on an active power calculation formula; Based on the instantaneous active power model, the fluctuation amount of the instantaneous active power is extracted through an adaptive filter according to the adaptive compensation coefficient.

6. The position-free closed-loop starting method of a permanent magnet synchronous motor according to claim 1, characterized in that: The permanent magnet synchronous motor is a surface mounted permanent magnet synchronous motor.

7. A position-free closed-loop starting system for a permanent magnet synchronous motor, characterized in that: include: A coordinate system determination module, configured to set the axis system where the given current vector of the permanent magnet synchronous motor is located as a virtual coordinate system, and the synchronous rotating coordinate system of the permanent magnet synchronous motor as an actual coordinate system; A discretized dynamic model establishment module is used to establish a discretized dynamic model based on the motion equation and torque equation of the permanent magnet synchronous motor; the discretized dynamic model is a set of differential equations of the dynamic motion model of the permanent magnet synchronous motor under I / F control; a variation law determination module, configured to solve the discretized dynamic model based on the Runge-Kutta method to determine the variation law of the fluctuation frequency and amplitude of the torque angle; An adaptive compensation coefficient determination module, configured to calculate in real time the adaptive filter cutoff frequency and the adaptive compensation coefficient of a given current vector according to the variation rules of the fluctuation frequency and the fluctuation amplitude; An instantaneous active power fluctuation extraction module is used to calculate the instantaneous active power in real time based on the voltage and current in the virtual coordinate system, and extract the instantaneous active power fluctuation through an adaptive filter; A speed fluctuation adjustment module is configured to automatically adjust the adaptive compensation coefficient according to the given acceleration of the given current vector, and to adjust the given speed of the given current vector in real time based on the fluctuation amount of the instantaneous active power, so that the virtual coordinate system and the actual coordinate system can quickly converge to a synchronous state when the speed fluctuates.

8. The position-free closed-loop starting system for a permanent magnet synchronous motor according to claim 7, characterized in that: The discretized dynamic model is: Among them, ω i is the rotating mechanical angular velocity of the given current vector; ω r is the actual mechanical angular velocity of the rotor, n p is the number of rotor pole pairs; ψ r is the permanent magnet flux amplitude; i s is a given current vector; θ is a torque angle, which is the angle between the quadrature axis in the virtual coordinate system and the direct axis in the actual coordinate system; J is the moment of inertia of the motor rotor; B is the viscous friction coefficient of the motor; T L is the load torque.

9. An electronic device, characterized in that: The electronic device comprises a memory and a processor, wherein the memory is used to store a computer program, and the processor runs the computer program to enable the electronic device to execute the position-free closed-loop starting method of a permanent magnet synchronous motor according to any one of claims 1 to 6.

10. A computer-readable storage medium, characterized in that It stores a computer program, which, when executed by a processor, implements the position-free closed-loop starting method for a permanent magnet synchronous motor according to any one of claims 1 to 6.

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