A permanent magnet synchronous motor position sensorless control method and system

Abstract

The present invention relates to the field of motor control technology, and specifically provides a position sensorless control method and system for a permanent magnet synchronous motor. A linear state observer is designed based on the stator voltage equation of the permanent magnet synchronous motor, and the error linear term in the linear state observer is replaced by a nonlinear function containing the error term to form a generalized nonlinear state observer, which is used to accurately obtain the estimated value of the motor's back electromotive force. The traditional orthogonal phase-locked loop is improved, and a parallel phase-locked loop structure is adopted to parallelly solve the back electromotive force estimates of the shaft and the shaft to obtain the rotor position estimate and the rotor speed estimate. The present invention designs a generalized nonlinear state observer and a parallel phase-locked loop structure to replace the traditional second-order linear state observer and cascaded orthogonal phase-locked loop structure, effectively improving the dynamic performance, anti-interference performance and rotor position estimation accuracy of the permanent magnet synchronous motor under complex working conditions.

Description

Technical Field

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

[0002] Permanent magnet synchronous motors (PMSMs) are increasingly used in both industrial and domestic applications due to their low energy loss, high power density, and efficient and precise control. To better control these motors, several high-performance control strategies have been developed. However, these approaches require accurate rotor position and speed information for closed-loop control. To avoid the increased size and cost of mechanical sensors that reduce system reliability, academia and industry have conducted extensive and in-depth research on sensorless control. Methods based on mathematical models of motors have made some progress in recent years with the introduction of state observers. For example, second-order linear state observers and cascaded orthogonal phase-locked loops (PLLs) have been used to estimate rotor speed and angle information. However, the low-pass filtering characteristics of second-order linear state observers, coupled with the fact that the frequency of the back-EMF is the same as the motor frequency, can cause phase lag when estimating the rapidly changing back-EMF during high-speed operation. Conventional PLLs use proportional-integral control as a loop filter, which degrades estimation performance during motor acceleration and deceleration and also suffers from poor noise reduction capabilities. Summary of the Invention

[0003] In view of this, the present invention aims to provide a position sensorless control method and system for a permanent magnet synchronous motor, constructs a new generalized nonlinear state observer to accurately extract the estimated back electromotive force of the motor, and adopts a parallel phase-locked loop to quickly extract position and speed information. Compared with the traditional second-order linear state observer and cascaded orthogonal phase-locked loop structure, the present invention effectively improves the back electromotive force estimation accuracy, thereby improving the motor's anti-interference ability and the dynamic performance of the phase-locked loop.

[0004] To achieve the above object, the technical solution created by the present invention is implemented as follows:

[0005] The present invention provides a position sensorless control method for a permanent magnet synchronous motor, comprising:

[0006] A generalized nonlinear state observer is established. The generalized nonlinear state observer replaces the error linear term in the linear state observer with a nonlinear function containing the error term. for:

[0007] ;

[0008] in, , express The error between the actual value of the stator current of the axis and the estimated value of the stator current, express The error between the actual value of the stator current of the axis and the estimated value of the stator current, is the symbol judgment function, 、 、 and is the parameter of the nonlinear function;

[0009] Using the generalized nonlinear state observer to obtain The estimated back EMF of the axis and Estimated back EMF of the shaft;

[0010] use The estimated back EMF of the axis and The motor rotor position error is calculated using the estimated value of the shaft's back electromotive force;

[0011] A parallel phase-locked loop is established and the rotor position estimation and rotor speed estimation are calculated using the parallel phase-locked loop according to the motor rotor position error.

[0012] Preferably, establishing a generalized nonlinear state observer includes:

[0013] According to the permanent magnet synchronous motor stator voltage equation, the linear state observer is established as:

[0014] ;

[0015] in, , express Estimated value of the stator current of the axis, express Estimated value of the stator current of the axis, , express Actual value of the stator current of the axis, express Actual value of the stator current of the axis, , express The estimated value of the unknown disturbance of the axis, express The estimated value of the unknown disturbance of the axis, , express The first derivative of the estimated back EMF of the shaft, express The first derivative of the estimated back EMF of the shaft, represents the electrical angular velocity of the motor, represents the motor system control gain, represents the input of the motor system, Indicates known interference, 、 and is the observer gain;

[0016] The error linear term in the linear state observer Replace with a nonlinear function , forming a generalized nonlinear state observer.

[0017] Preferably, the generalized nonlinear state observer is:

[0018] .

[0019] Preferably, the stator voltage equation of the permanent magnet synchronous motor is:

[0020] ;

[0021] in, express The stator voltage of the shaft, express The stator voltage of the shaft, represents the stator resistance of the motor, represents the stator inductance of the motor, express Actual value of the back EMF of the axis, express Actual value of the back EMF of the axis.

[0022] Preferably, establishing a linear state observer includes:

[0023] According to the stator voltage equation of the permanent magnet synchronous motor, the state space form of the motor system input, known disturbance and unknown disturbance is determined as follows:

[0024] ;

[0025] in, , represents the expanded unknown disturbance state variable, for The second derivative of

[0026] The state space form of the motor system's input, known disturbances and unknown disturbances is introduced into the stator voltage equation of the permanent magnet synchronous motor to establish a linear state observer.

[0027] Preferably, based on Estimated back EMF of the axis, The estimated back EMF value of the shaft determines the back EMF error including the motor rotor position error for:

[0028] ;

[0029] in, express Estimated value of the shaft back EMF, express Estimated value of the shaft back EMF, represents the actual rotor position, represents the rotor position estimate, Indicates the motor rotor position error.

[0030] Preferably, a parallel phase-locked loop is used to The estimated back EMF of the axis and The shaft back EMF estimates are solved in parallel to obtain rotor position estimates and rotor speed estimates.

[0031] Preferably, the rotor position is estimated and rotor speed estimation for:

[0032] ;

[0033] in, represents the integral coefficient of the parallel phase-locked loop, represents the proportional coefficient of the parallel phase-locked loop, represents the complex frequency-domain variable in the Laplace transform.

[0034] Preferably, when When, define , then the motor rotor position error Expressed as:

[0035] .

[0036] Another aspect of the present invention provides a permanent magnet synchronous motor position sensorless control system, which uses a permanent magnet synchronous motor position sensorless control method to obtain rotor position estimation and rotor speed estimation.

[0037] Compared with the prior art, the present invention can achieve the following beneficial effects:

[0038] The present invention employs a generalized nonlinear state observer and parallel phase-locked loop (PLL) structure to replace the traditional second-order linear state observer and cascaded orthogonal PLL structure. By replacing the linear error term with a nonlinear function, the observer can further track the actual equivalent back EMF, reducing the back EMF phase error, improving rotor estimation accuracy and anti-interference capabilities. Furthermore, it can more quickly track actual speed changes during motor acceleration and deceleration, effectively reducing the phase lag of back EMF estimation. Furthermore, the parallel PLL design converges the estimated rotor position error to zero during rapid motor acceleration and deceleration, enabling rapid response to speed changes, increasing speed tracking bandwidth, shortening step start time, and significantly improving the dynamic performance of the position-free drive system.

[0039] This invention significantly improves the dynamic response of the rotational speed and further enhances the ability to resist external load disturbances, making the motor system more robust. In addition, the sensorless design completely eliminates the mechanical position sensor, reducing system cost and mechanical complexity. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The accompanying drawings, which constitute part of the present invention, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0041] Figure 1 2 is a structural block diagram of a position sensorless control system for a permanent magnet synchronous motor according to an embodiment of the present invention;

[0042] Figure 2 is a flow chart of a position sensorless control method for a permanent magnet synchronous motor provided by an embodiment of the present invention;

[0043] Figure 3 2 is a schematic diagram of extracting back electromotive force estimation values ​​based on a generalized nonlinear state observer according to an embodiment of the present invention;

[0044] Figure 4 is a schematic diagram of extracting rotor position estimation and speed estimation based on a parallel phase-locked loop according to an embodiment of the present invention;

[0045] Figure 5 3. A comparison diagram of the method of the present invention and the traditional method for tracking different speeds during the motor speed change process provided by an embodiment of the present invention;

[0046] Figure 6 is a comparison diagram of rotor position error curves estimated by the method of the present invention and the traditional method during the motor speed change process provided by an embodiment of the present invention;

[0047] Figure 71 is a speed change curve of the method of the present invention and the traditional method at 12 Nm and -12 Nm load steps at 1000 rpm provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0048] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and do not constitute a limitation to the present invention. Similar elements in different embodiments use associated similar element numbers. In the following embodiments, many detailed descriptions are intended to enable the present invention to be better understood. However, those skilled in the art can easily recognize that some of the features can be omitted in different situations, or can be replaced by other elements, materials, or methods. In some cases, some operations related to the present invention are not shown or described in the specification. This is to avoid the core part of the present invention being overwhelmed by too much description. For those skilled in the art, it is not necessary to describe these related operations in detail. They can fully understand the related operations based on the description in the specification and the general technical knowledge in the art.

[0049] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other to form various implementation methods. At the same time, the steps or actions in the method description can also be interchanged or adjusted in a manner that is obvious to those skilled in the art. Therefore, the various orders in the description and the drawings are only for the purpose of clearly describing a certain embodiment and are not intended to be a required order, unless otherwise specified that a certain order must be followed.

[0050] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0051] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to internal connections between two components. Those skilled in the art can understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0052] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0053] See also Figure 1 In one embodiment of the present invention, a permanent magnet synchronous motor position sensorless control system is provided, which uses a permanent magnet synchronous motor position sensorless control method based on a new generalized nonlinear state observer and a parallel phase-locked loop to estimate the motor rotor position and speed. Specifically, the control system includes a speed controller, a current controller, a space vector pulse width modulation (SVPWM), a permanent magnet synchronous motor (PMSM), an inverter, and a sensorless observation module based on a new generalized nonlinear state observer and a parallel phase-locked loop. The speed controller is used to estimate the motor rotor position and speed according to a given speed. and rotor speed estimation using sensorless observation module PID algorithm is usually used to calculate the motor d-axis and q-axis current instructions. and ,and ; The current controller is based on the d-axis and q-axis current instructions and Calculate and obtain voltage instructions and , and then through Park inverse transformation, the voltage command and , transformed into Stator voltage of the shaft and Stator voltage of the shaft . Space Vector Pulse Width Modulation (SVPWM) is used to Stator voltage of the shaft and Stator voltage of the shaft Converted into six duty cycle signals PWM1, PWM2, PWM3, PWM4, PWM5 and PWM6. And through the inverter, the switch tube is controlled to turn on and off in a specific time sequence according to the duty cycle signal, and the power supply is Converted into the required three-phase electricity to drive the permanent magnet synchronous motor to rotate. During the motor rotation process, the three-phase current is collected in real time 、 and , and is obtained by Park transformation Actual value of the stator current of the axis and Actual value of the stator current of the axis , and then the current component in the dq coordinate system is obtained through Park inverse transformation and , and feeds back to the current controller. In addition, the sensorless observation module Actual value of the stator current of the axis 、 Actual value of the stator current of the axis 、 Stator voltage of the shaft and Stator voltage of the shaft , get the rotor position estimate and rotor speed estimation .

[0054] For rotor position estimation and rotor speed estimation The present invention proposes a method for obtaining position information from a permanent magnet synchronous motor without a position sensor. This method replaces the traditional second-order linear state observer and cascaded orthogonal phase-locked loop structure to quickly extract position and speed information, thereby improving the dynamic performance, anti-interference performance, and rotor position and speed estimation performance of the permanent magnet synchronous motor under complex working conditions. Figure 2 , the position sensorless control method of the permanent magnet synchronous motor includes the following steps:

[0055] S1: Based on the stator voltage equation of the permanent magnet synchronous motor, a new generalized nonlinear state observer is designed, and it is used to accurately estimate the internal back electromotive force of the system and obtain the estimated value of the back electromotive force.

[0056] Specifically, the permanent magnet synchronous motor stator voltage equation is established as:

[0057] ;

[0058] in, express Actual value of the stator current of the axis, express Actual value of the stator current of the axis, express The stator voltage of the shaft, express The stator voltage of the shaft, represents the stator resistance of the motor, represents the stator inductance of the motor, express Actual value of the back EMF of the axis, express Actual value of the back EMF of the axis.

[0059] According to the permanent magnet synchronous motor stator voltage equation, the motor system input, known disturbances, and unknown disturbances are rewritten into state space form and expressed as:

[0060] ;

[0061] in, represents the electrical angular velocity of the motor, represents the motor system control gain, represents the input of the motor system, , , , Indicates known interference, represents the expanded unknown disturbance state variable, for The second derivative of .

[0062] Combining the state space form of the motor system input, known disturbances, and unknown disturbances, as well as the permanent magnet synchronous motor stator voltage equation, a linear state observer for estimating back electromotive force is established as:

[0063] ;

[0064] in, , express Estimated value of the stator current of the axis, express Estimated value of the stator current of the axis, , express The estimated value of the unknown disturbance of the axis, express The estimated value of the unknown disturbance of the axis, , express The first derivative of the estimated back EMF of the shaft, , express The first derivative of the estimated back EMF of the shaft, , , express The error between the actual value of the stator current of the axis and the estimated value of the stator current, express The error between the actual value of the stator current of the axis and the estimated value of the stator current, 、 and is the observer gain.

[0065] Design includes error terms Nonlinear function for:

[0066] ;

[0067] in, is the symbol judgment function, 、 、 and are the parameters of the nonlinear function, , , , .

[0068] And the nonlinear function Bring it into the linear state observer and use the nonlinear function Replace the error linear term in the linear state observer to improve the back EMF estimation performance of the observer and obtain Figure 3 The new generalized nonlinear state observer shown in FIG2 can quickly respond to the speed increase and decrease changes of the load motor and quickly track the back electromotive force. The expression model of the generalized nonlinear state observer is:

[0069] .

[0070] The generalized nonlinear state observer can be used to estimate the system back electromotive force in real time and obtain Estimated back EMF of the axis and Estimated back EMF of the axis .

[0071] S2: Calculate the motor rotor position error based on the extended back electromotive force estimated by the generalized nonlinear state observer, and establish a parallel phase-locked loop to extract the rotor position estimation and rotor speed estimation.

[0072] Specifically, according to the observation of the generalized nonlinear state observer Estimated back EMF of the axis and Estimated back EMF of the axis , design the back EMF error including the motor rotor position error for:

[0073] ;

[0074] in, represents the actual rotor position, represents the rotor position estimate, Indicates the motor rotor position error.

[0075] Normally, when the rotor position error is small enough, there will be Therefore, in the embodiment of the present invention, when When, define , then the motor rotor position error It can be expressed as:

[0076] .

[0077] Get the motor rotor position error Then, based on the structure of the traditional orthogonal phase-locked loop, the following Figure 4 The dual-parallel phase-locked loop shown in the figure has two parallel branches. The estimated back EMF of the axis and The estimated back EMF of the shaft is solved in parallel to obtain the estimated rotor position and rotor speed estimation for:

[0078] ;

[0079] in, represents the integral coefficient of the parallel phase-locked loop, represents the proportional coefficient of the parallel phase-locked loop, represents the complex frequency-domain variable in the Laplace transform.

[0080] Therefore, the generalized nonlinear state observer and the parallel phase-locked loop can be used to obtain the motor rotor position estimation and rotor speed estimation, especially the rotor position and speed information can be accurately obtained during the motor speed change process.

[0081] In order to verify the effectiveness of the position sensorless control method of permanent magnet synchronous motor based on generalized nonlinear state observer and parallel phase-locked loop proposed in this invention. Set up a control group: use the traditional state observer combined with the phase-locked loop to estimate the rotor position and rotor speed; design an experimental group: use the method of this invention to conduct a combined simulation test under the same conditions. It should be noted that during the test, the speed controller, current controller, space vector pulse width modulation (SVPWM), permanent magnet synchronous motor (PMSM) and inverter are all designed with the same parameters, and the parameters in the speed controller are respectively , ; The parameters in the current controller are , , the observer gain coefficients are , the coefficients in the quadrature phase-locked loop , .

[0082] Based on the above conditions, the simulation results are:

[0083] like Figure 5 The comparison of the present invention's method and the traditional method in tracking different speed curves during the motor speed change process is shown in FIG. Figure 5 It can be seen from the figure that the method proposed in the present invention can track the actual speed to reach a stable state faster than the traditional method, which is beneficial to improving the dynamic performance of the position sensorless control system.

[0084] like Figure 6 The comparison of the rotor position error curves estimated by the method of the present invention and the traditional method during the motor speed change process is shown in FIG. Figure 6 It can be seen from the results that the rotor estimation error of the proposed method is significantly smaller than that of the traditional method, whether in different speed stable states or during speed increase and decrease, which reflects the superiority of the permanent magnet synchronous motor rotor position estimation method based on the new generalized nonlinear state observer and parallel phase-locked loop.

[0085] like Figure 7 The comparison of the speed change curves of the method of the present invention and the traditional method at 12Nm and -12Nm load steps at 1000rpm is shown in FIG. Figure 7 It can be seen that when 12Nm and -12Nm load step disturbances are applied to the motor system at 1000rpm, the speed dynamic response characteristics of the method proposed in the present invention are significantly improved compared with the traditional method: the speed fluctuation amplitude is reduced by 9rpm and the recovery time is shortened by 0.9s.

[0086] Simulation results show that compared to traditional methods, the generalized nonlinear state observer of the present invention can further track the actual equivalent back-electromotive force, reduce the back-electromotive force phase error, and improve the rotor estimation accuracy. At the same time, it can more quickly track the actual speed changes during the motor acceleration and deceleration process. Compared with the traditional orthogonal phase-locked loop method, during the rapid acceleration and deceleration of the motor, the parallel phase-locked loop of the present invention allows the estimated rotor position error to converge to zero and can quickly respond to speed changes, which helps to improve the dynamic performance of the positionless drive system. Applying the permanent magnet synchronous motor position sensorless control method proposed in the present invention to the motor system to form a permanent magnet synchronous motor position sensorless control system can effectively improve the motor's ability to resist external load disturbances.

[0087] In short, the above description is only a preferred embodiment of this specification and is not intended to limit the scope of protection of this specification. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of this specification shall be included in the scope of protection of this specification.

[0088] The systems, devices, modules, or units described in one or more of the above embodiments may be implemented by a computer chip or entity, or by a product having a certain function. 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.

[0089] 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.

[0090] The various embodiments in this specification are described in a progressive manner. Similar parts between the various embodiments can be referred to in conjunction with each other. Each embodiment focuses on the differences between the other embodiments. In particular, the system embodiments are generally similar to the method embodiments, so the description is relatively simple. For relevant parts, refer to the description of the method embodiments.

Claims

1. A position sensorless control method for a permanent magnet synchronous motor, characterized in that: include: A generalized nonlinear state observer is established, wherein the generalized nonlinear state observer replaces the error linear term in the linear state observer with a nonlinear function containing the error term. for: ； in, , express The error between the actual value of the stator current of the axis and the estimated value of the stator current, express The error between the actual value of the stator current of the axis and the estimated value of the stator current, is the symbol judgment function, 、 、 and is the parameter of the nonlinear function; Using the generalized nonlinear state observer to obtain The estimated back EMF of the axis and Estimated back EMF of the shaft; use The estimated back EMF of the axis and The motor rotor position error is calculated using the estimated value of the shaft's back electromotive force; Establish a parallel phase-locked loop, calculate the rotor position estimate and rotor speed estimate based on the motor rotor position error, and use the parallel phase-locked loop to calculate the rotor position estimate and rotor speed estimate. The estimated back EMF of the axis and The back electromotive force estimation value of the shaft is solved in parallel to obtain the rotor position estimation and rotor speed estimation. and rotor speed estimation for: ； in, represents the integral coefficient of the parallel phase-locked loop, represents the proportional coefficient of the parallel phase-locked loop, represents the complex frequency-domain variable in the Laplace transform.

2. The position sensorless control method for a permanent magnet synchronous motor according to claim 1, characterized in that: Establish a generalized nonlinear state observer, including: The linear state observer is established according to the permanent magnet synchronous motor stator voltage equation: ； in, , express Estimated value of the stator current of the axis, express Estimated value of the stator current of the axis, , express Actual value of the stator current of the axis, express Actual value of the stator current of the axis, , express The estimated value of the unknown disturbance of the axis, express The estimated value of the unknown disturbance of the axis, , express The first derivative of the estimated back EMF of the shaft, express The first derivative of the estimated back EMF of the shaft, represents the electrical angular velocity of the motor, represents the motor system control gain, represents the input of the motor system, Indicates known interference, 、 and is the observer gain; The error linear term in the linear state observer Replaced by the nonlinear function , forming the generalized nonlinear state observer.

3. The position sensorless control method for a permanent magnet synchronous motor according to claim 2, characterized in that: The generalized nonlinear state observer is: 。 4. The position sensorless control method for a permanent magnet synchronous motor according to claim 2, characterized in that: The stator voltage equation of the permanent magnet synchronous motor is: ； in, express The stator voltage of the shaft, express The stator voltage of the shaft, represents the stator resistance of the motor, represents the stator inductance of the motor, express Actual value of the back EMF of the axis, express Actual value of the back EMF of the axis.

5. The position sensorless control method for a permanent magnet synchronous motor according to claim 4, characterized in that: Establishing the linear state observer includes: According to the stator voltage equation of the permanent magnet synchronous motor, the state space form of the motor system input, known interference and unknown interference is determined as: ； in, , , represents the expanded unknown disturbance state variable, for The second derivative of The state space form of the motor system's input, known disturbances and unknown disturbances is introduced into the permanent magnet synchronous motor stator voltage equation to establish the linear state observer.

6. The position sensorless control method for a permanent magnet synchronous motor according to claim 1, characterized in that: in accordance with Estimated back EMF of the axis, The estimated back EMF value of the shaft determines the back EMF error including the motor rotor position error for: ； in, express Estimated value of the shaft back EMF, express Estimated value of the shaft back EMF, represents the actual rotor position, represents the rotor position estimate, Indicates the motor rotor position error.

7. The position sensorless control method for a permanent magnet synchronous motor according to claim 1 or 6, characterized in that: when When, define , then the motor rotor position error Expressed as: 。 8. A permanent magnet synchronous motor position sensorless control system, characterized in that: The rotor position estimation and the rotor speed estimation are obtained by using the position sensorless control method for a permanent magnet synchronous motor as claimed in any one of claims 1 to 7.

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