Full-speed-domain position-sensorless control method and system for surface-mounted permanent magnet synchronous motor

Abstract

The invention belongs to the technical field of permanent magnet synchronous motor position-sensorless control, and discloses a surface-mounted permanent magnet synchronous motor full-speed-domain position-sensorless control method and system. In a zero-low-speed area, a high-frequency square wave voltage injection method is adopted for motor rotor position identification, a simplified signal processing mode is adopted, use of a filter is omitted, and position estimation precision is improved; the improved sliding mode observer is adopted to identify the position of the motor rotor in a medium-high speed domain, and aiming at the problems of buffeting and phase delay of a traditional sliding mode observer, a piecewise square change switching function is adopted to replace a sign function to reduce system buffeting, and a synchronous reference system filter is adopted to replace a low-pass filter to reduce system buffeting. The problems of phase delay and amplitude attenuation caused by back electromotive force are avoided; and an improved weighted switching method with continuous and smooth proportionality coefficients is adopted in a switching speed domain to realize stable switching of the rotating speed. The method has the advantages of being capable of accurately estimating the motor rotating speed and the rotor position in the full-speed domain, fast in dynamic response and good in estimation precision.

Description

Technical Field

[0001] The present invention belongs to the technical field of position sensorless control of permanent magnet synchronous motors, and in particular relates to a full-speed range position sensorless control method and system for a surface-mounted permanent magnet synchronous motor. Background Art

[0002] In order to give full play to the performance advantages of PMSM, we need to achieve its high-performance control. However, traditional control strategies usually rely on position sensors, such as rotary encoders, Hall sensors, etc., to obtain accurate rotor position and angle information. In the aviation field, the installation of these sensors will not only increase the volume and weight of the system, but may also cause corrosion and failure due to impurities in gasoline, thus affecting the stability and reliability of the system. Therefore, the position sensorless control strategy has become a more reliable and efficient choice.

[0003] The sensorless control strategy calculates the rotor position information by using voltage and current signals, thus avoiding the use of physical sensors. To achieve full-speed sensorless control, the current mainstream method is to combine the control algorithms of the low-speed domain with the high-speed domain, and smoothly transition through the switching algorithm. Depending on the motor running speed, the PMSM sensorless control strategy is mainly divided into two categories:

[0004] One is a low-speed sensorless control method based on rotor salient effect control. Currently, the commonly used algorithms include rotating high-frequency voltage signal injection method, pulsating high-frequency voltage signal injection method, and high-frequency square wave signal injection method. These methods essentially use the salient pole effect of the motor to estimate the rotor position information, but the injection form is different. In addition, the high-frequency signal injection method introduces a filter during signal processing, and the addition of the filter will inevitably cause the estimated position signal to be delayed, and finally it needs to be compensated, which increases the control difficulty of the system. In addition, the injection of high-frequency signals will cause a large number of high-order harmonics to be mixed into the stator current, so it is not suitable for long-term operation.

[0005] The other type is the medium and high speed domain position sensorless control method represented by the fundamental wave model method. It mainly includes the extended Kalman filter method (EKF), the model reference adaptive method (MRAS), the back electromotive force integral method, the sliding mode observer method (SMO), etc. Among them, SMO has the advantages of strong robustness and good dynamic performance, and is the most widely used. The key to the sliding mode observer to achieve its good control performance lies in the selection of the sliding mode surface and the design of the switching function. Usually the switching function uses a sign function, which also leads to high-frequency jitter during the control process. At the same time, in order to extract the back electromotive force component of the motor, it is necessary to add a low-pass filter to the sliding mode observer design, which will cause the estimated back electromotive force to produce phase delay and amplitude attenuation, and as the speed increases, the influence of the low-pass filter on the stability of motor control will become greater and greater.

[0006] In addition, although the commonly used switching methods in the transition area, such as the hysteresis switching method and the linear average weighted switching method, are simple and easy to use, they have the problem of sudden changes in the switching proportion derivative at the switching critical point, that is, the switching proportion coefficient is discontinuous and not smooth, which affects the smoothness of the switching.

[0007] Through the above analysis, the problems and defects of the prior art are as follows:

[0008] At present, the permanent magnet synchronous motor full-speed domain position sensorless control uses the signal injection method to process the signal in the low-speed area, which will introduce a filter, resulting in a delay in the estimated position signal, which needs to be compensated, increasing the control difficulty of the system; in the medium and high-speed area, the sliding mode observer will produce high-frequency vibration and phase lag due to the use of switching functions and low-frequency filters, resulting in the inability to use its effective utilization components normally, which greatly reduces the operating performance of the system; the switching method commonly used in the transition area has the problem of sudden changes in the switching proportional derivative, that is, the switching proportional coefficient is discontinuous and not smooth, which affects the smoothness of the switching. Therefore, avoid the use of filters; effectively eliminate or reduce the high-frequency jitter phenomenon in the sliding mode observer, and optimize its design to reduce the negative effects of amplitude attenuation and phase delay; ensure smooth switching between zero low speed and medium and high speed sensorless control algorithms; it has great research significance and application value for improving the accuracy of rotor position and speed estimation, improving switching smoothness, improving system dynamic performance, and realizing reliable control of permanent magnet synchronous motor full-speed domain position sensorless. Summary of the invention

[0009] In view of the problems existing in the prior art, the present invention provides a position sensorless control method for a surface-mounted permanent magnet synchronous motor in the full speed range.

[0010] The present invention is implemented as follows: a full-speed range position sensorless control method for a surface-mounted permanent magnet synchronous motor comprises:

[0011] Step 1, identifying the rotor position and speed of the permanent magnet synchronous motor by improving the sliding film observer in the medium and high speed area;

[0012] Step 2, identifying the rotor position and speed of the permanent magnet synchronous motor by high-frequency square wave voltage injection method in the zero-speed region;

[0013] Step 3: In the transition region, an improved weighted switching algorithm is used to combine the high-frequency square wave voltage injection method with the improved sliding mode observer to obtain the rotor position and speed information.

[0014] Further, the specific method of step 1 is:

[0015] The rotor position information in the medium and high speed domain is obtained based on the improved sliding mode observer and speed information

[0016] In step 1, the scheme of improved sliding mode observer is adopted;

[0017] First, the current components in the three-phase stationary coordinate system are obtained by sampling: a ,i b ,i c ;

[0018] Then the three-phase current signal is transformed by clack to obtain the current component in the two-phase stationary coordinate system: α ,i β ; The current component i in the two-phase stationary coordinate system α ,i β The voltage component u in the two-phase stationary coordinate system obtained after the inverse park transformation α ,u β As the input of the improved sliding mode observer, the back EMF component is obtained through the sliding mode observer; the back EMF is filtered by a synchronous reference system filter, and the back EMF information is processed by an orthogonal phase-locked loop to obtain the difference signal

[0019] in and θ e1 Represent the estimated and actual rotor positions respectively; under the action of the PI regulator, the estimated error eventually converges to zero, and the electrical angle estimate is obtained, that is, the rotor position information Perform differential operation on it to obtain the estimated speed, that is, the speed information

[0020] Further, the specific method of step 2 is:

[0021] The rotor position information in the zero low speed domain is obtained by high frequency square wave voltage injection method and speed information

[0022] In step (2), a high-frequency square wave voltage injection method is used;

[0023] First, a high-frequency square wave voltage signal is injected into the d-axis in the two-phase rotating coordinate system. After the inverse park transformation and SVPWM module, a sinusoidal current signal for motor rotation control is generated. The current component in the three-phase stationary coordinate system is obtained by sampling: a ,i b ,i c ; Then the current components in the two-phase stationary coordinate system are obtained through the clack transformation: i α ,i β ;

[0024] Current component i α ,i β The signal separation is performed by using a filter-free separation strategy for the baseband signal and the high-frequency signal. The separated baseband signal is transformed by Park to obtain the current component i in the two-phase rotating coordinate system. d ,i q , and then introduce it into the current loop to perform double closed-loop control of the permanent magnet synchronous motor; the separated high-frequency signal is modulated by the rotation of the rotor, and the high-frequency current response contains the rotor position information. After obtaining the envelope curve of the high-frequency signal, the rotor position information is obtained using the phase-locked loop and speed information

[0025] When the motor speed is in the switching speed range, an improved weighted switching algorithm is used to combine the high-frequency square wave voltage injection method with the improved sliding film observer to obtain the rotor position information. and speed information Use position and speed information to achieve full-speed control of permanent magnet synchronous motor without position sensor;

[0026] The switching ratio weight coefficients are as follows:

[0027]

[0028] Among them, λ 1 , 2 are the weight coefficients of high-frequency square wave voltage injection method and improved synovial observer, ω 1 ,ω 2 are the upper and lower speed limits of the switching speed range, ω m For a given speed, the estimated motor rotor position and speed expressions obtained by combining the above two position-free algorithms are as follows:

[0029]

[0030] in and The algorithm fuses the estimated rotor position information and speed information.

[0031] Another object of the present invention is to provide a full-speed range position sensorless control system for a surface-mounted permanent magnet synchronous motor, comprising:

[0032] Identification module, used to identify the rotor position and speed of the permanent magnet synchronous motor in the medium and high speed area by using the improved sliding film observer; in the zero and low speed area, the rotor position and speed of the permanent magnet synchronous motor are identified by using the high-frequency square wave voltage injection method;

[0033] The combination module is used to obtain the rotor position and speed information by adopting an improved weighted switching algorithm in the transition region and combining the high-frequency square wave voltage injection method with the improved sliding mode observer scheme.

[0034] Another object of the present invention is to provide a computer device, which includes a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the surface-mounted permanent magnet synchronous motor full-speed range position sensorless control method.

[0035] Another object of the present invention is to provide a computer-readable storage medium storing a computer program, which, when executed by a processor, enables the processor to execute the steps of the surface-mounted permanent magnet synchronous motor full-speed range position sensorless control method.

[0036] Another object of the present invention is to provide an information data processing terminal, which is used to implement the full-speed range position sensorless control system of the surface-mounted permanent magnet synchronous motor.

[0037] In combination with the above technical solutions and the technical problems solved, the advantages and positive effects of the technical solutions to be protected by the present invention are as follows:

[0038] First, the present invention discloses a full-speed range permanent magnet synchronous motor position sensorless control method. The method exhibits better dynamic performance, has high-precision detection capability, and has excellent anti-interference performance and stronger anti-noise capability, thereby ensuring the stable and reliable operation of the permanent magnet synchronous motor. Specifically, the purpose of the present invention is to improve the following aspects:

[0039] The present invention adopts an improved sliding mode observer to identify the rotor position and speed in the medium and high speed domain. The improved sliding mode observer adopts a piecewise square switching function, which significantly reduces the system jitter phenomenon and improves the system stability; at the same time, a synchronous reference system filter is designed to replace the low-pass filter, thereby avoiding the phase delay and amplitude attenuation of the back electromotive force, without the need for additional phase compensation, ensuring the accuracy and reliability of the rotor position and speed identification.

[0040] The present invention adopts a high-frequency square wave voltage injection method to identify the rotor position and speed in the zero-speed domain. The high-frequency square wave voltage injection method uses only simple algebraic operations to complete the decoupling of high-frequency signals and low-frequency signals without using various filters, thus avoiding the adverse effects of introducing filters and ensuring the accuracy and reliability of rotor position and speed identification.

[0041] The invention designs an improved weighted switching method with a continuous and smooth switching ratio coefficient by using a high-order function curve in the transition region, overcomes the problem of discontinuous and non-smooth switching ratio coefficient, and realizes stable speed switching.

[0042] Second, as auxiliary evidence of the inventiveness of the claims of the present invention, it is also reflected in the following important aspects:

[0043] (1) The expected benefits and commercial value of the technical solution of the present invention after transformation are:

[0044] The present invention realizes the position sensorless control of the surface-mounted permanent magnet synchronous motor in the full speed range from the perspective of position and speed identification without position sensors and the improvement of position control performance without position sensors of the permanent magnet synchronous motor, and adopts a variety of optimization measures to ensure the accuracy and reliability of rotor position and speed identification, thereby improving the stability of the system. The permanent magnet synchronous motor control technology is the core technology in the new energy electric drive industry. The present invention provides an effective method for reducing the manufacturing cost of the motor control system and improving the stability of the control system, and has important application value and significance for the new energy electric drive industry.

[0045] (2) The technical solution of the present invention fills the technical gap in the industry at home and abroad:

[0046] The present invention mainly fills the gap that little attention has been paid to the impact of low-pass filters on the system when studying the position-free control method of permanent magnet synchronous motors at home and abroad. The introduction of the low-pass filter will cause phase delay and amplitude attenuation of the back electromotive force, which will affect the observation accuracy of the motor position and speed. The present invention designs a solution to this problem. First, in the position identification of high-frequency square wave injection, algebraic operations are used to complete the decoupling of high-frequency signals and low-frequency signals, reducing the use of filters. Secondly, a synchronous reference system filter is designed to replace the low-pass filter. The application of this filter does not require additional phase compensation, thereby improving the accuracy of rotor position and speed identification.

[0047] Third, the technical problems solved by the algorithm and model of the present invention are:

[0048] Accuracy of rotor position and speed identification: How to accurately identify the rotor position and speed of a permanent magnet synchronous motor in different speed ranges is a key issue.

[0049] Sensorless control: How to achieve full-speed sensorless control and improve system reliability and stability.

[0050] Smooth switching in transition areas: How to smoothly transition and ensure the continuity of the control system when switching between different speed areas.

[0051] Significant technical advances achieved by the algorithms and models of the present invention:

[0052] High-precision position and speed identification: A method combining an improved sliding mode observer and a high-frequency square wave voltage injection method is used to achieve high-precision rotor position and speed identification over the entire speed range.

[0053] Sensorless control: The sensorless full-speed control method solves the cost and reliability issues brought by traditional position sensors and enhances the robustness of the system.

[0054] Smooth transition and stability: The improved weighted switching algorithm achieves smooth transition between different speed areas, ensures the stability and continuity of the control system, and improves the dynamic performance of the system.

[0055] Advanced signal processing technology: The use of advanced signal processing technologies such as synchronous reference system filters, orthogonal phase-locked loops, and filter-free baseband signal and high-frequency signal separation strategies improves the accuracy and real-time performance of signal processing.

[0056] These technological advances enable this method to achieve efficient, stable and precise permanent magnet synchronous motor control over the entire speed range, which has significant application value and promotion prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 It is a flow chart of a full-speed range position sensorless control method for a surface-mounted permanent magnet synchronous motor provided by an embodiment of the present invention.

[0058] Figure 2 It is a structural block diagram of a full-speed range position sensorless control system for a surface-mounted permanent magnet synchronous motor provided by an embodiment of the present invention.

[0059] Figure 3 It is a block diagram of a permanent magnet synchronous motor full-speed range position sensorless system provided by an embodiment of the present invention.

[0060] Figure 4It is a principle block diagram of rotor position information estimation of an improved sliding mode observer provided by an embodiment of the present invention.

[0061] Figure 5 It is a principle block diagram of a synchronous reference frame filter designed according to an embodiment of the present invention.

[0062] Figure 6 It is a structural block diagram of a sliding mode observer phase-locked loop provided by an embodiment of the present invention.

[0063] Figure 7 It is a coordinate axis relationship diagram provided by an embodiment of the present invention.

[0064] Figure 8 This is a relationship diagram of the injected high-frequency square wave and its current response provided by an embodiment of the present invention.

[0065] Fig. 9 It is a block diagram of separating baseband signals and high-frequency signals provided by an embodiment of the present invention.

[0066] Fig.10 It is a block diagram of error extraction estimation using a high-frequency square wave voltage injection method provided by an embodiment of the present invention.

[0067] Fig.11 It is an improved weighting function diagram provided by an embodiment of the present invention.

[0068] Fig.12 It is an experimental waveform under no-load condition for verifying the solution provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0069] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0070] Application Example 1: Electric Vehicle Drive System

[0071] Electric vehicle drive systems require efficient and reliable motor control to ensure stable vehicle operation under varying speed and load conditions.

[0072] 1) Medium and high speed area operation:

[0073] When electric vehicles are running at medium and high speeds, an improved sliding mode observer scheme is adopted.

[0074] According to the current signal of the electric vehicle motor in the three-phase stationary coordinate system, the current component in the two-phase stationary coordinate system is obtained through Clark transformation.

[0075] The two-phase current components are converted into voltage components using inverse Park transformation and input into the improved sliding mode observer to obtain the back electromotive force.

[0076] The back electromotive force signal is processed by a synchronous reference frame filter and an orthogonal phase-locked loop to obtain the rotor position and speed information.

[0077] The PI regulator is used to adjust the rotor position information so that the estimated error converges to zero and ensures stable operation of the motor.

[0078] 2) Operation in zero and low speed area:

[0079] When starting or driving at low speed, a high-frequency square wave voltage injection method is used.

[0080] A high-frequency square wave voltage signal is injected into the d-axis of the motor, and a sinusoidal current signal is generated through inverse Park transformation and SVPWM module.

[0081] The sampled current signal in the three-phase stationary coordinate system is converted into the current component in the two-phase stationary coordinate system through Clark transformation.

[0082] The high-frequency current response signal is separated by using a filter-free baseband signal and high-frequency signal separation strategy, and the envelope curve of the high-frequency signal is obtained. The rotor position and speed information are obtained through a phase-locked loop.

[0083] 3) Transition zone operation:

[0084] When the speed of the electric vehicle changes, an improved weighted switching algorithm is used.

[0085] According to the given speed range, the switching ratio weight coefficient is calculated, and the rotor position and speed information of the high-frequency square wave voltage injection method and the improved sliding mode observer are integrated.

[0086] The fused position information and speed information are adjusted by the PI regulator to ensure the smooth operation of the electric vehicle in the transition area.

[0087] This method achieves efficient and stable control of electric vehicles over the full speed range, improves the operating efficiency and control accuracy of the motor, reduces dependence on traditional position sensors, and reduces costs and failure rates.

[0088] Application Example 2: Motor drive system for aviation fuel pump

[0089] The motor drive system for aviation fuel pumps requires high-precision, high-dynamic response motor control to ensure control performance and safety during operation.

[0090] 1) Medium and high speed area operation:

[0091] When the motor for aviation fuel pump runs at high speed, an improved sliding mode observer scheme is adopted.

[0092] The current signal of the motor in the three-phase stationary coordinate system is obtained, and the current component in the two-phase stationary coordinate system is obtained through Clark transformation.

[0093] The voltage component is input into the improved sliding mode observer using inverse Park transform to obtain the back electromotive force.

[0094] The back electromotive force signal is processed by a synchronous reference frame filter and an orthogonal phase-locked loop to obtain the rotor position and speed information.

[0095] Use PI regulator to adjust the position information to ensure stable and precise control of CNC machine tools during high-speed movement.

[0096] 2) Operation in zero and low speed area:

[0097] When running at low speed or starting, high-frequency square wave voltage injection method is used.

[0098] A high-frequency square wave voltage signal is injected into the d-axis of the motor, and a sinusoidal current signal is generated through the inverse Park transform and SVPWM module.

[0099] The sampled current signal in the three-phase stationary coordinate system is converted into the current component in the two-phase stationary coordinate system through Clark transformation.

[0100] The high-frequency current response signal is separated by using a filter-free baseband signal and high-frequency signal separation strategy, and the envelope curve of the high-frequency signal is obtained. The rotor position and speed information are obtained through a phase-locked loop.

[0101] 3) Transition zone operation:

[0102] When the speed of the motor for aviation fuel pump changes, an improved weighted switching algorithm is used.

[0103] According to the given speed range, the switching ratio weight coefficient is calculated, and the rotor position and speed information of the high-frequency square wave voltage injection method and the improved sliding mode observer are integrated.

[0104] The fused position information and speed information are adjusted by the PI regulator to ensure the smooth operation of the motor for the aviation fuel pump when the speed changes.

[0105] The method realizes efficient and precise control of the motor for the aviation fuel pump in the full speed range, improves the control performance and efficiency, reduces the use of position sensors, and improves the reliability and maintainability of the system.

[0106] The above two embodiments demonstrate the application of the position sensorless control method in electric vehicle drive systems and motor drive systems for aviation fuel pumps. Through efficient and stable control over the entire speed range, the operating efficiency, control accuracy and system reliability of the motor are improved, and the method has significant application value and promotion prospects.

[0107] like Figure 1 As shown, a full-speed range position sensorless control method for a surface-mounted permanent magnet synchronous motor provided by an embodiment of the present invention comprises the following steps:

[0108] S101, identifies the rotor position and speed of the permanent magnet synchronous motor in the medium and high speed range by improving the sliding film observer;

[0109] S102, identifying the rotor position and speed of the permanent magnet synchronous motor by a high-frequency square wave voltage injection method in a zero-speed region;

[0110] S103, in the transition region, an improved weighted switching algorithm is used to combine the high-frequency square wave voltage injection method with the improved sliding mode observer method to obtain the rotor position and speed information.

[0111] The specific method of step 1 provided in the embodiment of the present invention is as follows:

[0112] The rotor position information in the medium and high speed domain is obtained based on the improved sliding mode observer and speed information

[0113] In step 1, the scheme of improved sliding mode observer is adopted;

[0114] First, the current components in the three-phase stationary coordinate system are obtained by sampling: a ,i b ,i c ;

[0115] Then the three-phase current signal is transformed by clack to obtain the current component in the two-phase stationary coordinate system: α ,i β ; The current component i in the two-phase stationary coordinate system α ,i β The voltage component u in the two-phase stationary coordinate system obtained after the inverse park transformation α ,u β As the input of the improved sliding mode observer, the α and β axis back EMF components are obtained through the sliding mode observer;

[0116] The back EMF is filtered by a synchronous reference filter and the back EMF information is processed by an orthogonal phase-locked loop to obtain a difference signal.

[0117] in and θ e1 Represent the estimated and actual rotor positions respectively; under the action of the PI regulator, the estimated error eventually converges to zero, and the electrical angle estimate is obtained, that is, the rotor position information Perform differential operation on it to obtain the estimated speed, that is, the speed information

[0118] The specific method of step 2 provided in the embodiment of the present invention is as follows:

[0119] The rotor position information in the zero low speed domain is obtained by high frequency square wave voltage injection method and speed information

[0120] In step (2), a high-frequency square wave voltage injection method is used;

[0121] First, a high-frequency square wave voltage signal is injected into the d-axis in the two-phase rotating coordinate system. After the inverse park transformation and SVPWM module, a sinusoidal current signal for motor rotation control is generated. The current component in the three-phase stationary coordinate system is obtained by sampling: a ,i b ,i c ;

[0122] Then the current components in the two-phase stationary coordinate system are obtained through the clack transformation: α ,i β ;

[0123] The current component contains high-frequency current response and baseband current response. A filter-free separation strategy for baseband signal and high-frequency signal is used for signal separation. The separated baseband signal is transformed by Park to obtain the current component i in the two-phase rotating coordinate system. d ,i q , and then introduce it into the current loop to perform double closed-loop control of the permanent magnet synchronous motor; the separated high-frequency signal is modulated by the rotation of the rotor, and the high-frequency current response contains the rotor position information. After obtaining the envelope curve of the high-frequency signal, the rotor position information is obtained using the phase-locked loop and speed information

[0124] When the motor speed is in the switching speed range, an improved weighted switching algorithm is used to combine the high-frequency square wave voltage injection method with the improved sliding film observer to obtain the rotor position information. and speed information Use position and speed information to achieve full-speed control of permanent magnet synchronous motor without position sensor;

[0125] The switching ratio weight coefficients are as follows:

[0126]

[0127] Among them, λ 1 , 2 are the weight coefficients of high-frequency square wave voltage injection method and improved synovial observer, ω1 ,ω 2 are the upper and lower speed limits of the switching speed range, ω m For a given speed, the estimated motor rotor position and speed expressions obtained by combining the above two position-free algorithms are as follows:

[0128]

[0129] in and The algorithm fuses the estimated rotor position information and speed information.

[0130] like Figure 2 As shown, a full-speed range position sensorless control system for a surface-mounted permanent magnet synchronous motor provided by an embodiment of the present invention includes:

[0131] Identification module, used to identify the rotor position and speed of the permanent magnet synchronous motor in the medium and high speed area by using the improved sliding film observer; in the zero and low speed area, the rotor position and speed of the permanent magnet synchronous motor are identified by using the high-frequency square wave voltage injection method;

[0132] The combination module is used to obtain the rotor position and speed information by adopting an improved weighted switching algorithm in the transition region and combining the high-frequency square wave voltage injection method with the improved sliding mode observer scheme.

[0133] Another object of the present invention is to provide a computer device, which includes a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the surface-mounted permanent magnet synchronous motor full-speed range position sensorless control method.

[0134] Another object of the present invention is to provide a computer-readable storage medium storing a computer program, which, when executed by a processor, enables the processor to execute the steps of the surface-mounted permanent magnet synchronous motor full-speed range position sensorless control method.

[0135] Another object of the present invention is to provide an information data processing terminal, which is used to implement the full-speed range position sensorless control system of the surface-mounted permanent magnet synchronous motor.

[0136] The present invention is specifically implemented:

[0137] Figure 3 This is a control principle block diagram of the present invention, which adopts FOC vector control with id=0, including a coordinate transformation module, an SVPWM module, a current loop module, a speed loop module, a permanent magnet synchronous motor module, a sliding mode detector module, a high frequency injection module and a switching module.

[0138] The present invention limits the speed of the permanent magnet synchronous motor to less than ω 1 For low speed domain, higher than ω 2 The low speed range is generally lower than 10% of the rated speed in practice. The rated speed of the permanent magnet synchronous motor used in the practice of the present invention is 12000r / min, so in this example, ω 1 Take 900r / min, ω 2 Take 1000r / min.

[0139] Step 1

[0140] When the motor speed is higher than ω 2 , using an improved sliding mode observer to identify the rotor position information in the medium and high speed domain and speed information The principle diagram of rotor position information estimation of improved sliding mode observer is as follows: Figure 4 shown.

[0141] First, establish the voltage equation of the permanent magnet synchronous motor in rotating coordinates:

[0142]

[0143] Where: L d , L q is the dq axis stator inductance, surface mounted permanent magnet synchronous motor L d =L q =L; R is the stator resistance; ω e is the electrical angular velocity; ψ f is the magnetic link; u d ,u q are the dq axis voltage components of the stator winding respectively; i d ,i q They are the dq axis current components of the stator winding respectively;

[0144] By applying clack to the above formula, the mathematical model of the two-phase αβ stationary coordinate system can be obtained as follows:

[0145]

[0146] in

[0147]

[0148] θ e is the rotor position angle; i α ,i β is the stator current; u α ,u β is the stator voltage; E α , E β is the back electromotive force.

[0149] Formula (5) can be transformed into the current equation as follows:

[0150]

[0151] In order to obtain the back electromotive force E α , E β , the sliding mode observer can be designed as shown in formula (7).

[0152]

[0153] There is an estimated symbol above, which means that these two current values ​​are estimated by the observer to distinguish them from the actual measured current values. α ,i β ;v α , v β is the control input of the sliding mode device, which can be expressed by equation (8): where h represents the piecewise square switching function designed by the present invention, and k represents the sliding mode gain.

[0154]

[0155] The h expression is as follows:

[0156]

[0157] In the formula, a is the boundary thickness. The larger the value of a, the faster the function converges to ±1, that is, the faster the system responds, but the greater the jitter; the smaller the value of a, the slower the function converges to ±1, that is, the slower the system responds, but the smaller the jitter. Therefore, it is necessary to select a suitable value of a to meet the requirements of the system's control accuracy and response speed.

[0158] is the current observation error. Subtracting equation (6) from equation (7) yields equation (10):

[0159]

[0160] The sliding mode hyperplane function is defined as:

[0161]

[0162] If the sliding mode observer is stable and convergent, after it enters the sliding mode, the current error and its current error derivative must be zero, as shown in the following formula:

[0163]

[0164] Then, substituting equation (12) into the sliding mode observer current error equation (10), the estimated value of the back electromotive force can be obtained as shown in equation (13):

[0165]

[0166] The back EMF extracted by the sign function contains a large number of switching quantities. The existence of harmonics makes it impossible to directly use it for position information estimation. Otherwise, the position observation value will fluctuate greatly, and even the position information cannot be estimated. Therefore, a low-pass filter is required to obtain a relatively clean back EMF. However, the low-pass filter will cause the back EMF to have phase delay and amplitude attenuation problems.

[0167] Therefore, the present invention designs a synchronous reference system filter to filter the back electromotive force, thereby avoiding the problem of phase delay and amplitude attenuation of the back electromotive force. Figure 5 shown.

[0168] When acquiring the rotor position information, the most commonly used and simplest method is to use the inverse tangent function to directly calculate it. However, the inverse tangent function jitters back and forth near the zero point, which will reduce the robustness of the system. Therefore, the present invention acquires the position angle through a phase-locked loop structure. The structure of the traditional phase-locked loop is as follows: Figure 6 As shown. and θ e Represent the actual and estimated rotor positions respectively; K p , K i are the proportional gain and integral gain of the PI regulator. According to the block diagram, the electrical angle estimation error expression (14) can be obtained. Under the action of the PI regulator, the estimation error eventually converges to zero. At this time, the estimated rotor position value can be used instead of the actual rotor position, and the estimated speed can be used instead of the actual speed.

[0169]

[0170] Step 2

[0171] When the motor speed is lower than ω 1 , using high-frequency square wave voltage injection method to identify the rotor position information in the zero low-speed domain and speed information

[0172] The coordinate system of permanent magnet synchronous motor is as follows Figure 7 The motor voltage equation in the synchronous rotating coordinate system is shown in equation (3).

[0173] When the motor speed is low and the frequency of the injected high-frequency signal is much greater than the frequency of the fundamental signal, the motion potential term of the permanent magnet motor is very small, so the influence of the back electromotive force term can be ignored. At the same time, the influence of the stator resistance can be ignored. Then the model of the permanent magnet motor can be equivalent to a pure inductive load, so that the voltage equation of the permanent magnet synchronous motor can be simplified to:

[0174]

[0175] In the formula, u dh ,u qh is the high-frequency voltage component in the dq axis system; i dh ,i qh is the high-frequency current in the dq axis system; L dh , L qh is the high-frequency inductance of the dq axis; h represents the quantity related to the high-frequency signal.

[0176] In the estimation The axis coordinates are injected with a high-frequency square wave signal with half the frequency of the PWM carrier signal, and the injected voltage is as shown in formula (16):

[0177]

[0178] In the formula, is the high-frequency injected voltage component in the dq axis system; V in is the high frequency injected voltage amplitude.

[0179] According to the coordinate transformation theory, the two-phase static αβ coordinate system is transformed into the actual rotating dq axis current, which can be expressed as shown in formula (17):

[0180]

[0181] In the formula, i αh ,i βh is the high-frequency current component in the αβ axis system; θ e is the actual electrical angle of the rotor.

[0182] Similarly, according to the coordinate transformation relationship, it is estimated that The relationship between the voltage and the actual dq axis voltage can be expressed by equation (18):

[0183]

[0184] In the formula, Estimate the electrical angle for the rotor; is the position estimation error.

[0185] Substituting equations (18) and (17) into (15), we can obtain:

[0186]

[0187] In the formula, ω h is the angular frequency of the high-frequency current response.

[0188] Substituting the injected high-frequency signal into the above formula, the high-frequency current response can be obtained as shown in formula (20):

[0189]

[0190] In the formula, L=(L dh +L qh ) / 2 is the average inductance; ΔL=(L dh -L qh ) / 2 is the differential inductance.

[0191] According to the positive or negative of the injected high-frequency square wave signal, the sign function can be used to combine the high-frequency current response envelope obtained by equation (20) as follows:

[0192]

[0193] In the formula, I cos ,I sin is the high-frequency current response envelope; sgn is the sign function.

[0194] At this time, the square wave signal response current in the αβ coordinate system can be obtained by using a filter-free separation strategy of the baseband signal and the high-frequency signal. The relationship diagram of the injection of high-frequency square wave and its current response in the present invention is as follows: Figure 8 The relationship between the sampling current, base frequency current and high frequency current can be expressed as formula (22).

[0195] i αβs =i αβl +i αβh (twenty two)

[0196] In the formula, i αβs 、i αβl 、i αβh They are sampling current, base frequency current and high frequency current respectively.

[0197] After simple algebraic operations, the fundamental frequency current and high frequency current response can be separated, as shown in equation (23). The implementation block diagram is as follows: Fig. 9 shown.

[0198]

[0199] Since the high-frequency current signal is modulated by the rotation of the rotor, the high-frequency current response contains the rotor position information. The observer can then be used to estimate the rotor position and speed information. Without using a mechanical position sensor, combined with the basefrequency current signal, the permanent magnet synchronous motor can achieve position sensorless dual closed-loop control.

[0200] When the observer converges, it is estimated Angular difference between the axis system and the synchronously rotating dq axis system Then formula (21) can be simplified as:

[0201]

[0202] After obtaining the envelope curve of the high-frequency current response, the estimated error is obtained by using the vector difference multiplication method. The processing method is as follows: Fig.10 As shown; after using the vector difference multiplication method to obtain the observation error, an observer is needed to track the position of the actual synchronous coordinate system. The present invention uses a PI observer to achieve zero-static-error tracking of the actual rotor position.

[0203] Step 3

[0204] When the motor speed is 1 ≤ω≤ω 2 In the interval, the improved weighted switching algorithm designed by the present invention is used to combine the high-frequency square wave voltage injection method with the improved synovial observer to obtain the rotor position information. and speed information Therefore, the position and speed information can be used to realize sensorless full-speed control of the permanent magnet synchronous motor.

[0205] Aiming at the problem that the switching proportional coefficient of the traditional switching method is not smooth, this paper designs a switching method with continuous and smooth switching proportional coefficient by using high-order function curve. The designed continuous and smooth high-order function is as follows:

[0206]

[0207] According to formula (25), the switching ratio weight coefficient is designed as follows:

[0208]

[0209] Among them, λ 1 , 2 are the weight coefficients of the improved synovial observer and the high-frequency square wave voltage injection method, ω 1 ,ω 2 are the upper and lower speed limits of the switching speed range, ω m is the given speed. The speed switching proportional coefficient is shown in the figure below: Fig.11 As shown. The estimated motor rotor position and speed expressions obtained by integrating the above two position-free algorithms are as follows:

[0210]

[0211] in and The algorithm fuses the estimated rotor position information and speed information.

[0212] When the motor speed ω≤ω 1 When the weight coefficient λ of the high-frequency injection scheme is 2 =1, weight coefficient λ of the improved sliding mode observer scheme 1= 0, only high frequency injection scheme is used to estimate rotor position and rotor speed;

[0213] When the motor speed ω ≥ ω 2 When the weight coefficient λ of the high-frequency injection scheme is 2 =0, weight coefficient λ of the improved sliding mode observer scheme 1 = 1, only the improved sliding mode observer is used to estimate the rotor position and rotor speed;

[0214] When the motor speed is 1 ≤ω≤ω 2 The weight coefficient is estimated in the interval. After the rotor position and rotor speed are estimated at different speeds, the motor is controlled according to the vector control method, so that the permanent magnet synchronous motor can rotate smoothly in the full speed range.

[0215] In summary, the present invention provides a full-speed range position sensorless control method for a permanent magnet synchronous motor. The method uses an improved sliding mode observer method at medium and high speeds, a high-frequency square wave voltage injection method at low speeds, and finally achieves smooth switching through an improved weighted average switching method, which has the advantage of being able to accurately estimate the motor speed and rotor position at full speed.

[0216] It should be noted that the embodiments of the present invention can be implemented by hardware, software, or a combination of software and hardware. The hardware part can be implemented using dedicated logic; the software part can be stored in a memory and executed by an appropriate instruction execution system, such as a microprocessor or dedicated design hardware. It can be understood by a person of ordinary skill in the art that the above-mentioned devices and methods can be implemented using computer executable instructions and / or contained in a processor control code, such as a carrier medium such as a disk, CD or DVD-ROM, a programmable memory such as a read-only memory (firmware), or a data carrier such as an optical or electronic signal carrier. Such code is provided on the carrier medium. The device and its modules of the present invention can be implemented by hardware circuits such as very large-scale integrated circuits or gate arrays, semiconductors such as logic chips, transistors, etc., or programmable hardware devices such as field programmable gate arrays, programmable logic devices, etc., can also be implemented by software executed by various types of processors, and can also be implemented by a combination of the above-mentioned hardware circuits and software, such as firmware.

[0217] Example 1: Full-speed range position-free control of a permanent magnet synchronous motor for an aviation fuel pump

[0218] Background: In the aviation field, the installation of mechanical sensors not only increases the volume and weight of the system, but may also cause corrosion and failure due to impurities in gasoline, thus affecting the stability and reliability of the system. Therefore, in order to achieve stable, reliable and efficient control of permanent magnet synchronous motors for fuel pumps, position sensorless control strategies have become an inevitable choice.

[0219] The experimental verification results of the present invention are as follows Fig.12 As shown. The experimental control algorithm is implemented by RT-LAB real-time simulator. The motor driver uses RTI-INV6010IR three-phase full-bridge inverter, and the permanent magnet synchronous motor uses the original three-phase permanent magnet synchronous motor in the laboratory. The parameters of the permanent magnet synchronous motor are as follows: number of pole pairs: 2 pairs of poles; line resistance: 76.4mΩ; dq axis inductance: 0.017mH; inverter switching frequency is 10kHz; controller frequency is 100kHz. The rated speed is 12000r / min.

[0220] The control algorithm of the present invention adopts FOC vector control with id=0, which includes a coordinate transformation module, an SVPWM module, a current loop module, a speed loop module, a permanent magnet synchronous motor module, a sliding mode detector module, a high frequency injection module and a switching module.

[0221] The experimental verification results of the present invention are as follows Fig.12 It can be seen that the sensorless observation method designed in the present invention has good control performance in observing the dynamic response of the high-speed permanent magnet synchronous motor.

[0222] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any modifications, equivalent substitutions and improvements made by any technician familiar with the technical field within the technical scope disclosed by the present invention and within the spirit and principle of the present invention should be covered by the protection scope of the present invention.

Claims

1. A full-speed range position sensorless control method for a surface-mounted permanent magnet synchronous motor, characterized in that: The following steps are involved: Step 1, identifying the rotor position and speed of the permanent magnet synchronous motor by improving the sliding film observer in the medium and high speed area; Step 2, identifying the rotor position and speed of the permanent magnet synchronous motor by high-frequency square wave voltage injection method in the zero-speed region; Step 3: In the transition region, an improved weighted switching algorithm is used to combine the high-frequency square wave voltage injection method with the improved sliding mode observer to obtain the rotor position and speed information.

2. The full-speed range position sensorless control method for a surface-mounted permanent magnet synchronous motor according to claim 1, characterized in that: The specific method of step 1 is as follows: In step 1, the scheme of improved sliding mode observer is adopted; The rotor position information in the medium and high speed domain is obtained based on the improved sliding mode observer and speed information First, the current components in the three-phase stationary coordinate system are obtained by sampling: a ,i b ,i c ; Then the three-phase current signal is transformed by clack to obtain the current component in the two-phase stationary coordinate system: α ,i β ; The current component i in the two-phase stationary coordinate system α ,i β The voltage component u in the two-phase stationary coordinate system obtained after the inverse park transformation α ,u β As the input of the improved sliding mode observer, the back electromotive force is obtained through the sliding mode observer; The back EMF is filtered by a synchronous reference filter and the back EMF information is processed by an orthogonal phase-locked loop to obtain a difference signal. in and θ e Represent the estimated and actual rotor positions respectively; under the action of the PI regulator, the estimated error eventually converges to zero, and the electrical angle estimate is obtained, that is, the rotor position information Perform differential operation on it to obtain the estimated speed, that is, the speed information 3. The full-speed range position sensorless control method for a surface-mounted permanent magnet synchronous motor as claimed in claim 1, characterized in that: The specific method of step 2 is: The rotor position information in the zero low speed domain is obtained by high frequency square wave voltage injection method and speed information In step (2), a high-frequency square wave voltage injection method is used; First, a high-frequency square wave voltage signal is injected into the d-axis in the two-phase rotating coordinate system. After the inverse park transformation and SVPWM module, a sinusoidal current signal for motor rotation control is generated. The current component in the three-phase stationary coordinate system is obtained by sampling: a ,i b ,i c ; Then the current components in the two-phase stationary coordinate system are obtained through the clack transformation: α ,i β ; The current component contains high-frequency current response and baseband current response. A filter-free separation strategy for baseband signal and high-frequency signal is used for signal separation. The separated baseband signal is transformed by Park transform to obtain the current component i in the two-phase rotating coordinate system. d ,i q ; Then it is introduced into the current loop to perform double closed-loop control of the permanent magnet synchronous motor; the separated high-frequency signal is modulated by the rotation of the rotor, and the high-frequency current response contains the rotor position information. After obtaining the envelope curve of the high-frequency signal, the rotor position information is obtained using a phase-locked loop. and speed information When the motor speed is in the switching speed range, an improved weighted switching algorithm is used to combine the high-frequency square wave voltage injection method with the improved sliding film observer to obtain the rotor position information. and speed information Use position and speed information to achieve full-speed control of permanent magnet synchronous motor without position sensor; The switching ratio weight coefficients are as follows: Among them, λ1 and λ2 are the weight coefficients of the high-frequency square wave voltage injection method and the improved sliding film observer, ω1 and ω2 are the upper and lower speed limits of the switching speed domain, and ω m For a given speed, the estimated motor rotor position and speed expressions obtained by combining the above two position-free algorithms are as follows: in and The algorithm fuses the estimated rotor position information and speed information.

4. A surface-mounted permanent magnet synchronous motor full-speed range position sensorless control system implementing the surface-mounted permanent magnet synchronous motor full-speed range position sensorless control method as claimed in any one of claims 1 to 3, characterized in that: The control system includes: An improved sliding film observer module for identifying the rotor position and speed of a permanent magnet synchronous motor in the medium and high speed region; A high-frequency square wave voltage injection module for identifying the permanent magnet synchronous motor rotor position and speed in the zero and low speed region; An improved weighted switching algorithm module is used to combine the high-frequency square wave voltage injection method with the improved sliding mode observer scheme in the transition region to obtain the rotor position and speed information; Among them, the improved sliding mode observer module performs Clark transformation, inverse Park transformation and sliding mode observation on the three-phase current signal obtained by sampling, and finally processes the back electromotive force information through the synchronous reference frame filter and the orthogonal phase-locked loop to obtain the rotor position information and speed information; The high-frequency square wave voltage injection module injects a high-frequency square wave voltage signal into the d-axis in the two-phase rotating coordinate system, and obtains the rotor position information and speed information by separating the baseband signal from the high-frequency signal without a filter and processing the high-frequency signal through a phase-locked loop.

5. The full-speed range position sensorless control system of a surface-mounted permanent magnet synchronous motor according to claim 1, characterized in that: The improved sliding mode observer module specifically includes: A sampling device for obtaining current components in a three-phase stationary coordinate system; A Clark transformer is used to transform the three-phase current signal into current components in a two-phase stationary coordinate system; An inverse park converter is used to input the voltage components in the two-phase stationary coordinate system into the improved sliding mode observer; A sliding mode observer is used to obtain the shaft back electromotive force component through the input current component and voltage component; a synchronous reference frame filter to filter the back EMF; An orthogonal phase-locked loop is used to process the back-EMF information to obtain the rotor position and speed information.

6. The full-speed range position sensorless control system of a surface-mounted permanent magnet synchronous motor according to claim 1, characterized in that: The high-frequency square wave voltage injection module specifically includes: a high-frequency square wave voltage signal generator, used for injecting a high-frequency square wave voltage signal into the d-axis in the two-phase rotating coordinate system; an inverse park converter and SVPWM module to generate a sinusoidal current signal for motor rotation control; A sampling device for obtaining current components in a three-phase stationary coordinate system; A Clark transformer is used to transform the three-phase current signal into current components in a two-phase stationary coordinate system; a signal separator for performing signal separation using a filter-free baseband signal and high frequency signal separation strategy; A park converter is used to convert the base frequency signal into a current component in a two-phase rotating coordinate system and introduce it into the current loop for double closed-loop control; A phase-locked loop is used to obtain the envelope curve of the high-frequency signal to obtain the rotor position information and speed information.

7. A computer device, characterized in that: The computer device includes a memory and a processor, the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the full-speed range position sensorless control method for a surface-mounted permanent magnet synchronous motor as described in any one of claims 1-3.

8. A computer-readable storage medium storing a computer program, wherein when the computer program is executed by a processor, the processor executes the steps of the full-speed range position sensorless control method for a surface-mounted permanent magnet synchronous motor as described in any one of claims 1 to 3.

9. An information data processing terminal, characterized in that: The information data processing terminal is used to implement the full-speed range position sensorless control system of the surface-mounted permanent magnet synchronous motor as described in claim 4.

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