Full-speed-domain position-sensorless control method for permanent magnet synchronous motor

Abstract

The invention relates to the technical field of sensors, and discloses a full-speed-domain position-sensorless control method for a permanent magnet synchronous motor. The full-speed-domain position-sensorless control method for the permanent magnet synchronous motor comprises the following steps: S1, realizing a high-frequency pulsating injection method in a zero-low-speed domain, injecting a high-frequency pulsating signal into a motor system, and extracting rotor position information according to system response characteristics; s2, estimating the position and the speed of a rotor in real time in a medium-high speed domain by adopting a super-spiral sliding mode observer method; and S3, adopting a composite control strategy, and combining the two methods to realize full-speed-domain composite control. According to the full-speed-domain position-sensorless control method for the permanent magnet synchronous motor, the high-frequency pulsating injection method and the super-spiral sliding-mode observer method are combined, position-sensorless high-precision control over the permanent magnet synchronous motor in the full-speed domain is achieved, the control performance is effectively improved, the system cost and complexity are reduced, and the control precision is improved. And the application prospects in multiple fields are widened.

Description

Technical Field

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

[0002] Traditional position sensors are commonly used to detect the position and speed of permanent magnet synchronous motor systems, but they may increase the complexity, cost and failure rate of the system. The emergence of full-speed domain position sensorless control technology solves this problem. By estimating the rotor position and speed, high-performance control of permanent magnet synchronous motors is achieved while reducing the burden and failure rate of the system. The present invention combines the high-frequency pulse injection method suitable for the zero-low speed domain with the sliding mode observer method suitable for the medium and high speed domain, and improves the design of the second-order sliding mode observer-super spiral sliding mode observer, which overcomes the disturbance problem of conventional single sensorless control methods in different speed ranges, weakens the jitter phenomenon caused by traditional sliding mode observers, and realizes the operation of the permanent magnet synchronous motor sensorless control system in the full speed range.

[0003] Existing technologies similar to the present invention include: sliding mode observer method, high-frequency pulse injection method, model reference adaptive method, extended Kalman filter method and artificial intelligence algorithm, etc., but they have disadvantages such as over-reliance on motor parameters, high hardware requirements, immature technology and only good control effect in the corresponding speed domain.

[0004] In summary, in the prior art, the sensor control technology has the following problems:

[0005] ① Full-speed control problem: The traditional permanent magnet synchronous motor position sensorless control method often performs poorly at low and high speeds;

[0006] ② Accurate estimation of rotor position: The position sensorless control method requires accurate estimation of the rotor position. In the low-speed area, the traditional observer method may have unstable performance, while in the high-speed area, higher accuracy is required;

[0007] ③ Jitter of the sliding mode observer method: In the medium and high speed domain, the sliding mode control function of the traditional sliding mode observer is a discontinuous high-frequency switching function, which will cause jitter in the speed.

[0008] Therefore, the present invention combines the control methods respectively applicable to the zero-low speed domain and the medium-high speed domain to obtain a composite control method to achieve a better control effect. Summary of the invention

[0009] In order to solve the above technical problems, the present invention provides a full-speed domain position sensorless control method for a permanent magnet synchronous motor. By adopting a full-speed domain control method, a high-frequency pulse injection method suitable for a zero-low speed domain is combined with a super-helical sliding mode observer method suitable for a medium-high speed domain to form a position sensorless composite control method, which can achieve high-performance control in the entire speed range, including accurate speed tracking and rotor position estimation, thereby solving the full-speed domain control problem; by adopting a high-frequency pulse injection method in the zero-low speed domain and a super-helical sliding mode observer method in the medium-high speed domain, the problem of accurately estimating the rotor position is solved; by designing a second-order sliding mode observer, the speed fluctuation of the system is reduced and the jitter phenomenon is weakened, thereby solving the jitter problem of the sliding mode observer method.

[0010] To achieve the above object, the present invention provides a permanent magnet synchronous motor full speed range position sensorless control method comprising the following steps:

[0011] S1. Implement high-frequency pulse injection method in the zero-speed domain, inject high-frequency pulse signal into the motor system, and extract rotor position information according to the system response characteristics;

[0012] S2, using the super-helical sliding mode observer method in the medium and high speed domain to estimate the rotor position and speed in real time;

[0013] S3. Adopt a composite control strategy and combine the above two methods to realize composite control in the full speed range.

[0014] Preferably, the high-frequency pulse injection method comprises the following steps:

[0015] S1.1. In the zero-speed domain, a high-frequency pulse signal is injected into the motor system by a high-frequency pulse injection method;

[0016] S1.2, extracting rotor position information according to system response characteristics;

[0017] S1.3. Use the extracted rotor position information in combination with the control algorithm to achieve zero low-speed control.

[0018] Preferably, the superhelical sliding mode observer method comprises the following steps:

[0019] S2.1, in the medium and high speed domain, the super-helical sliding mode observer method is used for rotor position estimation;

[0020] S2.2, in designing a super-helical sliding mode observer to estimate the rotor position and speed in real time;

[0021] S2.3, in combination with control algorithms to achieve control in the medium and high speed domains.

[0022] Preferably, the composite control strategy comprises the following steps:

[0023] S3.1. According to the motor operating state and speed, a switching logic is designed (the present invention adopts the weighted coefficient method) to decide when to switch to the high-frequency pulse injection method or the super-helical sliding mode observer method for rotor position estimation.

[0024] S3.2. The rotor position information obtained by the two estimation methods is combined into the control algorithm (the present invention adopts vector control (FOC)) to realize composite control in the full speed range.

[0025] Preferably, the super spiral sliding mode observer algorithm comprises:

[0026] The switching function that generates chattering is placed in the second-order derivative, and the chattering is effectively reduced through the filtering effect of the integral;

[0027] According to the observed quantity, which is the current error value of the motor in the two-phase stationary coordinate system, two sliding surfaces are designed;

[0028] On the sliding surface, the estimated back electromotive force is used as the control function to complete the estimation of the back electromotive force, and then the rotor position and speed are obtained through the speed angle observer.

[0029] Compared with the related art, the permanent magnet synchronous motor full-speed range position sensorless control method provided by the present invention has the following beneficial effects:

[0030] ① High-performance control in the full-speed domain: The present invention combines the high-frequency pulse injection method suitable for the zero-speed domain with the super-helical sliding mode observer method suitable for the medium-speed domain, thereby realizing high-performance control of the permanent magnet synchronous motor (PMSM) in the full-speed domain. By adopting different rotor position estimation methods in different speed regions, it can overcome the poor performance of traditional methods at the low and high speed ends, thereby realizing stable and precise control in the full-speed domain.

[0031] ② No position sensor requirement: The present invention does not require the installation of additional position sensors. By using a composite control strategy that combines high-frequency pulse injection method and super-helical sliding mode observer method, position sensorless control of PMSM can be achieved; this reduces system cost and complexity and improves system reliability and stability.

[0032] ③ Optimization of control performance: The present invention adopts two different rotor position estimation methods and automatically switches according to the motor operating status, which can achieve optimal control performance in different speed areas; and in response to the jitter phenomenon caused by the traditional sliding mode observer method, the present invention designs a second-order sliding mode observer, namely the super-helical sliding mode observer, which weakens the jitter phenomenon; by estimating the rotor position and speed in real time, the torque and speed of the motor can be controlled more accurately, thereby improving the dynamic response capability and control accuracy of the system.

[0033] ④Wide range of applications: The present invention is suitable for various fields that require high-performance motor control, including industrial drives, electric vehicles, aerospace, etc.; by providing an efficient and stable position sensorless control solution, it can promote the application and development of electrification technology in various fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 A schematic diagram of a full-speed range position sensorless control method for a permanent magnet synchronous motor provided by the present invention;

[0035] Figure 2 Schematic diagram of the weighted coefficient method used in the composite control strategy. DETAILED DESCRIPTION

[0036] The present invention will be further described below in conjunction with the accompanying drawings and implementation modes.

[0037] Please refer to Figure 1-2 A method for controlling a permanent magnet synchronous motor in full speed range without a position sensor provided by the present invention comprises the following steps:

[0038] S1. Implement high-frequency pulse injection method in the zero-speed domain, inject high-frequency pulse signal into the motor system, and extract rotor position information according to the system response characteristics;

[0039] S2, using the super-helical sliding mode observer method in the medium and high speed domain to estimate the rotor position and speed in real time;

[0040] S3. Adopt a composite control strategy and combine the above two methods to realize composite control in the full speed range.

[0041] The high frequency pulse injection method comprises the following steps:

[0042] S1.1. In the zero-speed domain, a high-frequency pulse signal is injected into the motor system by a high-frequency pulse injection method;

[0043] S1.2, extracting rotor position information according to system response characteristics;

[0044] S1.3. Use the extracted rotor position information in combination with the control algorithm to achieve zero low-speed control.

[0045] Wherein, the super spiral sliding mode observer method comprises the following steps:

[0046] S2.1, in the medium and high speed domain, the super-helical sliding mode observer method is used for rotor position estimation;

[0047] S2.2, in designing a super-helical sliding mode observer to estimate the rotor position and speed in real time;

[0048] S2.3, in combination with control algorithms to achieve control in the medium and high speed domains.

[0049] Wherein, the composite control strategy comprises the following steps:

[0050] S3.1. According to the motor operating state and speed, a switching logic is designed (the present invention adopts the weighted coefficient method) to decide when to switch to the high-frequency pulse injection method or the super-helical sliding mode observer method for rotor position estimation.

[0051] S3.2. The rotor position information obtained by the two estimation methods is combined into the control algorithm (the present invention adopts vector control (FOC)) to realize composite control in the full speed range.

[0052] Further explanation:

[0053] ①Super helical sliding mode observer method:

[0054] The super-helical sliding mode observer is a type of second-order sliding mode observer. Unlike the traditional sliding mode, the second-order sliding mode puts the switching function that produces jitter into the second-order derivative. The jitter can be effectively reduced through the filtering effect of the integral. The second-order algorithm ensures the continuity of the first-order derivative and weakens the jitter. At the same time, the switching function is still used in the control process to ensure the anti-interference and robustness of the system.

[0055] The super-helical second-order sliding mode algorithm consists of continuous functions and discrete differentials, which can be expressed as follows:

[0056]

[0057] If r is set to 0.5 and the system disturbance is ignored, the expression can be written as:

[0058]

[0059] According to the observation quantity as the current error value of the motor in the two-phase stationary coordinate system, two sliding surfaces are designed as follows:

[0060]

[0061] in, is the estimated current value; i α 、i β is the actual feedback current value.

[0062]

[0063] When the observer operates in a stable state, the system state point moves on the sliding surface, that is, the estimated back electromotive force is used as the control function to be measured, and the control model can be simplified as follows:

[0064]

[0065] In summary, the back electromotive force can be estimated through the second-order sliding mode control algorithm, and after completing the above process, the observed rotor position and speed can be obtained through the speed angle observer.

[0066] ②Compound control strategy:

[0067] The composite control strategy uses the weighted coefficient method (such as Figure 2 As shown in the figure), in the weighted coefficient method, the switching threshold ω between the zero low speed and medium high speed interval is set L ,ω H , then the speed range of the weighted composite output is (ω H -ω L ). When the speed is less than ω L When the speed exceeds ω, the system only uses high-frequency pulse injection control; H When , the system will be controlled by the super-helical sliding mode observer; in the weighted interval (ω H -ω L ), the composite control module will calculate a weighted value according to the weight of the current speed in the interval, and reorganize the two control strategies for composite output. In the transition interval, as the speed continues to increase, the closer it approaches the switching threshold ω H , the higher the output proportion of the medium and high speed strategy, the smaller the proportion of the low speed control strategy, and gradually achieves a smooth transition of the advantage strategy in different speed ranges. When the arrow from right to left is from high speed to low speed, the change process of the weight value is the same as that from low speed to high speed.

[0068] The weighting coefficient expression can be written as:

[0069]

[0070] Among them, λ is the weight value in the compound control, is the currently observed speed. In the weighted transition interval, the weight value is calculated by the proportion of the currently observed speed to the entire speed interval.

[0071] The speed and rotor position expressions of the compound control output are:

[0072]

[0073] The two control algorithms are weighted and reorganized by using weight ratio to achieve smooth transition of control methods and realize position sensorless composite control in the full speed range.

[0074] Example:

[0075] For example, in the experiment, the motor can be started from zero speed and the speed can be gradually increased. Under the zero-speed condition, only the high-frequency pulse injection method is used to estimate the rotor position of the PMSM. Then, according to the set transition interval, when the lower limit speed of the transition interval is reached, the proportion of the high-frequency pulse injection method is gradually reduced, and the proportion of the super-helical sliding mode observer method is gradually increased. That is, the two rotor position estimation methods are used at the same time. When the speed exceeds the upper limit speed of the set transition interval, only the super-helical sliding mode observer method is used to estimate the rotor position, thereby achieving smooth switching of the control method of the PMSM in the full speed range and realizing position sensorless composite control.

[0076] Compared with the related art, the permanent magnet synchronous motor full-speed range position sensorless control method provided by the present invention has the following beneficial effects:

[0077] ① Position sensorless control strategy: The present invention realizes position sensorless control of PMSM. By adopting different control methods for different speed domains, the rotor position estimation of two speed domains is realized, and high-precision control of the motor can be achieved without installing additional position sensors. The key point is to combine the high-frequency pulse injection method suitable for zero and low speed domains with the super-helical sliding mode observer method suitable for medium and high speed domains, so as to realize high-performance control of PMSM in the full speed domain. Therefore, the technical key points of the present invention include the fusion of two rotor position estimation methods and the design of switching strategies.

[0078] ② Full-speed domain composite control: The high-frequency pulse injection method applicable to the zero and low-speed domain and the super-helical sliding mode observer method applicable to the medium and high-speed domain are combined through the weighted coefficient method. The high-frequency pulse injection method is used in the zero and low-speed domain. When the speed increases to the transition interval, the proportion of the high-frequency pulse injection method is gradually reduced, and the proportion of the super-helical sliding mode observer method is gradually increased. When the speed exceeds the upper limit of the transition interval, only the sliding mode observer method is used to achieve smooth switching of PMSM control methods in the full-speed domain and achieve the purpose of high-performance control.

[0079] ③ Optimization of control algorithm: The present invention aims to improve the design of sliding mode observer to address the shortcomings of traditional sliding mode observer, namely, the continuous small vibration of system state on the sliding mode surface due to the switching function, and adopts the second-order sliding mode - super spiral sliding mode observer to weaken the vibration phenomenon and optimize the control algorithm.

[0080] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for controlling a permanent magnet synchronous motor without a position sensor at full speed, characterized in that: The following steps are involved: S1. Implement high-frequency pulse injection method in the zero-speed domain, inject high-frequency pulse signal into the motor system, and extract rotor position information according to the system response characteristics; S2, using the super-helical sliding mode observer method in the medium and high speed domain to estimate the rotor position and speed in real time; S3. Adopt a composite control strategy and combine the above two methods to realize composite control in the full speed range.

2. The method for controlling a permanent magnet synchronous motor in full speed range without position sensor according to claim 1, characterized in that: The high frequency pulse injection method comprises the following steps: S1.

1. In the zero-speed domain, a high-frequency pulse signal is injected into the motor system by a high-frequency pulse injection method; S1.2, extracting rotor position information according to system response characteristics; S1.

3. Use the extracted rotor position information in combination with the control algorithm to achieve zero low-speed control.

3. The permanent magnet synchronous motor full speed range position sensorless control method according to claim 1, characterized in that: The super spiral sliding mode observer method comprises the following steps: S2.1, in the medium and high speed domain, the super-helical sliding mode observer method is used for rotor position estimation; S2.2, in designing a super-helical sliding mode observer to estimate the rotor position and speed in real time; S2.3, in combination with control algorithms to achieve control in the medium and high speed domains.

4. The permanent magnet synchronous motor full speed range position sensorless control method according to claim 1, characterized in that: The composite control strategy comprises the following steps: S3.

1. According to the motor running state and speed, design a switching logic, that is, use the weighted coefficient method to decide when to switch to the high-frequency pulse injection method or the super-helical sliding mode observer method for rotor position estimation; S3.

2. The rotor position information obtained by the two estimation methods is combined into the control algorithm, namely vector control, to achieve composite control in the full speed range.

5. The method for controlling a permanent magnet synchronous motor in full speed range without position sensor according to claim 1, characterized in that: The super spiral sliding mode observer algorithm includes: The switching function that generates chattering is placed in the second-order derivative, and the chattering is effectively reduced through the filtering effect of the integral; According to the observed quantity, which is the current error value of the motor in the two-phase stationary coordinate system, two sliding surfaces are designed; On the sliding surface, the estimated back electromotive force is used as the control function to complete the estimation of the back electromotive force, and then the rotor position and speed are obtained through the speed angle observer.

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