阅读说明：本技术 一种用于五相永磁容错电机无位置传感器控制方法 (Position-sensorless control method for five-phase permanent magnet fault-tolerant motor ) 是由 张丽 朱孝勇 韩赛 沈东� 于 2021-01-15 设计创作，主要内容包括：本发明公开了一种用于五相永磁容错电机无位置传感器控制方法,属于多相电机无位置传感器控制技术领域。先建立基于反电势的五相永磁容错电机的任两相数学模型；再利用双曲线函数构建基于任两相信号的电流状态观测器以获取相应的相反电势；然后构建通用锁相环模块,将所述正常两相反电势输入通用锁相环模块,计算得到电机转速和转子位置。该方法能够有效抑制系统中高频抖振,解决相位延迟问题,提高转子位置的估算精度；省去坐标变换,提高了系统的鲁棒性,使得电机在故障模式下和参数变化扰动下均具有较好的跟踪能力；此外,其算法计算量小,简单易于实现,有利于新理论的工程化和实用化。(The invention discloses a position sensorless control method for a five-phase permanent magnet fault-tolerant motor, and belongs to the technical field of position sensorless control of multi-phase motors. Firstly, establishing any two-phase mathematical model of a five-phase permanent magnet fault-tolerant motor based on back electromotive force; then, a current state observer based on any two-phase signals is constructed by using a hyperbolic function to obtain corresponding opposite potentials; and then constructing a universal phase-locked loop module, inputting the two normal opposite potentials into the universal phase-locked loop module, and calculating to obtain the rotating speed and the rotor position of the motor. The method can effectively inhibit high-frequency buffeting in the system, solve the problem of phase delay and improve the estimation precision of the rotor position; coordinate transformation is omitted, robustness of the system is improved, and the motor has good tracking capability under a fault mode and parameter change disturbance; in addition, the algorithm has small calculation amount, is simple and easy to realize, and is beneficial to the engineering and the practicability of a new theory.)

1. A control method for a five-phase permanent magnet fault-tolerant motor position-free sensor is characterized by comprising the following steps:

step 1) establishing any two-phase mathematical model of a five-phase permanent magnet fault-tolerant motor based on back electromotive force;

step 2) constructing a current state observer based on any two-phase signals by using a hyperbolic function to obtain corresponding opposite potentials;

and 3) constructing a universal phase-locked loop (PLL) module, inputting the two normal opposite potentials into the universal PLL module, and calculating to obtain the rotating speed and the rotor position of the motor.

2. The position sensorless control method of the five-phase permanent magnet fault-tolerant motor according to claim 1, wherein the specific steps of step 1) comprise:

the voltage equation of any two phases of the five-phase permanent magnet fault-tolerant motor is expressed as

In the formula, R_sAnd L_sRespectively a stator resistor and an inductor; x, y e (1,2, …, 5); u. of_xAnd u_yThe x phase voltage and the y phase voltage respectively; i.e. i_xAnd i_yThe x phase current and the y phase current respectively; e.g. of the type_xAnd e_yRespectively, the x-th phase and the y-th opposite potential, expressed as

Wherein E is_m＝ω_eγ_e；γ_eAnd theta_eBack emf coefficient and rotor position electrical angle, ω, respectively_eIs the angular velocity.

3. The position sensorless control method of the five-phase permanent magnet fault-tolerant motor according to claim 2, wherein the specific steps of step 2) include:

2.1) selecting sliding mode variable structure function

The hyperbolic function is used as a sliding mode variable structure function to reconstruct any two-phase voltage equation of the five-phase permanent magnet fault-tolerant motor, and the equation can be expressed as

Wherein the content of the first and second substances,andestimated currents for the x-phase and the y-phase, respectively;the difference between the estimated current and the actual current for the x-phase,estimating a difference between the current and the actual current for the y-phase; λ is the sliding mode coefficient;andis a hyperbolic function expressed as:

wherein a is a real number greater than zero and can be adjusted according to actual conditions;

2.2) constructing a current state observer based on any two-phase signals

And (3) taking a hyperbolic function as a sliding mode variable structure function in the step 2.1) to obtain a voltage equation of the five-phase permanent magnet fault-tolerant motor and a voltage equation in the step 2.2) as a difference, so as to obtain a current state observer based on any two-phase signals:

wherein e is_xAnd e_yCounter-current for x-phase and y-phase respectivelyPotential; in the observer, the boundary layer is defined as the independent variable when H is 0.99, the boundary layer can be effectively adjusted by adjusting the value a, the counter electromotive force harmonic content is further improved, the high-frequency harmonic of the observer can be effectively reduced by increasing the value a, and the counter electromotive force harmonic content is greatly reduced.

4. The position sensorless control method of the five-phase permanent magnet fault-tolerant motor according to claim 3, wherein the specific steps of step 3) comprise:

estimated back emf of x-phase and y-phase based on rotor position rangeIt must satisfy:

thus, it is possible to obtain:

the phase error of the phase detector is expressed as:

wherein E is_mIs the back emf amplitude; the two formulas can be obtained, the output delta e of the phase discriminator is the estimated rotor position error, and the estimated rotor position error delta e can be used for obtaining the estimated rotating speed information through a loop filterWhile filtering Δ e through the loopRotor position information from wave filter and voltage controlled oscillator

Technical Field

The invention belongs to the technical field of multi-phase motor position sensorless control, and particularly relates to a position sensorless control method for a five-phase permanent magnet fault-tolerant motor.

Background

The five-phase permanent magnet fault-tolerant motor has the advantages of high efficiency, high power density, wide speed regulation range, low torque pulsation, strong fault-tolerant capability and the like, and is widely concerned and applied in the fields of aerospace, electric automobiles, ship propulsion systems and the like. For a five-phase permanent magnet fault-tolerant motor control system, a mechanical position sensor is generally required to detect the position and the rotating speed of a rotor. However, the use of mechanical sensors not only increases the cost and volume of the system, but also decreases the reliability of the system, thereby limiting its application to high performance drive applications. Therefore, the research on the position sensorless control of the five-phase permanent magnet fault-tolerant motor is of great significance.

The sliding-mode observer has the characteristics of simple principle, good stability and the like, so that the sliding-mode observer becomes a research hotspot in the field of control research of the motor position-free sensor. However, the conventional sliding mode observer has large buffeting of a no-position control system, and meanwhile, due to the use of a low-pass filter, the problem of phase delay is caused, a phase compensation link is generally required to be added, so that not only can the structural complexity of the sliding mode observer be increased, but also the dynamic and static tracking capability of an estimation system can be reduced. On the other hand, when the five-phase fault-tolerant motor winding fails, the corresponding fault-tolerant control strategy is adopted, so that the motor driving system can continuously run without interference, and the reliability of the motor driving system is improved. However, the motor phase winding in the fault mode is in an asymmetric running state, normal phase current is distorted, and if an observer is constructed by directly utilizing coordinate transformation, the estimation accuracy in the fault mode is greatly reduced. In addition, the problems with conventional sliding mode observers will be further exacerbated in failure modes.

Disclosure of Invention

The purpose of the invention is as follows: aiming at the problems in the prior art, the control method of the five-phase permanent magnet fault-tolerant motor position-free sensor with high robustness and without compensation is provided, a low-pass filter is omitted, phase compensation and coordinate transformation are not needed, the motor driving system can be ensured to have good tracking performance under normal and fault working conditions, and the motor driving system has good disturbance resistance and dynamic and static performances.

The technical scheme is as follows: in order to achieve the purpose of the invention, the technical scheme adopted by the invention is as follows: a control method for a five-phase permanent magnet fault-tolerant motor without a position sensor comprises the following steps:

step 1) establishing any two-phase mathematical model of a five-phase permanent magnet fault-tolerant motor based on back electromotive force;

step 2) constructing a current state observer based on any two-phase signals by using a hyperbolic function to obtain corresponding opposite potentials;

and 3) constructing a universal phase-locked loop (PLL), inputting the two normal opposite potentials into a universal PLL module, and calculating to obtain the rotating speed of the motor and the position of the rotor.

Further, the specific process of the step 1) is as follows:

the voltage equation of any two phases of the five-phase permanent magnet fault-tolerant motor is expressed as

In the formula, R_sAnd L_sRespectively a stator resistor and an inductor; x, y ∈ 1,2, …, 5; u. of_xAnd u_yThe x phase voltage and the y phase voltage; i.e. i_xAnd i_yThe x-phase current and the y-phase current; e.g. of the type_xAnd e_yIs the opposite potential of the x phase and the y phase and is expressed as

Wherein E is_m＝ω_eγ_e；γ_eAnd theta_eBack emf coefficient and rotor position electrical angle, respectively.

Further, the specific process of the step 2) is as follows:

2.1) selecting a sliding mode variable structure function.

The hyperbolic function is used as a sliding mode variable structure function, and any two-phase voltage equation of the five-phase permanent magnet fault-tolerant motor is reconstructed and can be expressed as

Wherein the content of the first and second substances,to estimate the currentThe difference from the actual current; λ is the sliding mode coefficient;andis a hyperbolic function expressed as:

wherein a is a real number greater than zero and can be adjusted according to actual conditions.

2.2) constructing a current state observer based on any two-phase signals.

And (3) taking a hyperbolic function as a sliding mode variable structure function in the step 2.1) to obtain a voltage equation of the five-phase permanent magnet fault-tolerant motor and a voltage equation in the step 2.2) as a difference, so as to obtain a current state observer based on any two-phase signals:

in this observer, the magnitude of the independent variable is defined when the boundary layer H is 0.99. The boundary layer can be effectively adjusted by adjusting the value of a, so that the counter potential harmonic content is improved. By increasing the value a, the high-frequency harmonic of the observer can be effectively reduced, and the harmonic content of the observed counter electromotive force is greatly reduced, so that the constructed observer does not need a low-pass filter, a rotor position error compensation link can be omitted, and the construction of the universal PLL in the step 3 can be simplified.

2.3) analyzing the stability condition of the observer according to the existence and stability condition of the sliding mode motion.

Further, the specific process of step 3) is as follows:

estimating back emf based on rotor position rangeMust be full ofFoot:

thus, it is possible to obtain:

the phase error of the phase detector is expressed as:

the two equations can be used to obtain the output delta e of the phase discriminator as the estimated rotor position error. The estimated rotor position error delta e is processed by a loop filter to obtain estimated rotating speed informationMeanwhile, the delta e can be used for obtaining the position information of the rotor through a loop filter and a voltage-controlled oscillator

The invention has the beneficial effects that:

1) according to the control method, coordinate transformation is omitted, any two-phase mathematical model of the five-phase permanent magnet fault-tolerant motor based on the back electromotive force is constructed to obtain the position information of the rotor, so that the phases have no mutual influence, the robustness of the system is improved, and the motor has good tracking capability under a fault mode and parameter change disturbance.

2) The invention utilizes a hyperbolic function as a sliding mode variable structure function to construct a current state observer based on any two-phase signals, effectively weakens the buffeting phenomenon in a system by adjusting variable structure parameters, solves the problems of low estimation precision, complex algorithm and the like caused by using a low-pass filter and a position error compensation link in the traditional sliding mode observer, simplifies a control algorithm, and improves the dynamic and static estimation precision of the observer.

3) The invention firstly comprehensively applies a current state observer, a hyperbolic sliding mode variable structure function and a general phase-locked loop based on any two-phase signals to a five-phase permanent magnet fault-tolerant motor position-less sensor control system, realizes high-precision rotor position and rotating speed estimation under the normal operation condition and the fault operation condition of the motor, and effectively improves the fault-tolerant performance and reliability of a motor driving system;

4) the control method without the position sensor has small calculation amount, is simple and easy to realize, and is beneficial to engineering and practicability of a new theory.

Drawings

Fig. 1 is a schematic structural diagram of a five-phase permanent magnet fault-tolerant motor;

FIG. 2 is a block diagram of the control method of the present invention;

FIG. 3 is a block diagram of a conventional sliding-mode observer;

FIG. 4 is a hyperbolic function of the present invention;

FIG. 5 is a block diagram of a generic PLL in accordance with the present invention;

fig. 6 shows the simulation results of the present invention. (a) And (b) estimating the back emf for the BC phase, while (c) and (d) estimating the back emf for the AC phase.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

As shown in fig. 1, the control object of the invention is a five-phase permanent magnet fault-tolerant motor, which comprises a stator, a rotor, a permanent magnet, armature teeth, fault-tolerant teeth and an armature winding; the armature teeth and the fault-tolerant teeth are uniformly distributed at intervals along the circumferential direction of the inner ring of the stator, and the tooth widths of the armature teeth are not equal to those of the fault-tolerant teeth; armature winding coils are wound on the armature teeth and are single-layer concentrated windings, and two adjacent single-layer concentrated windings are isolated by fault-tolerant teeth; permanent magnets are embedded in the rotor and distributed in a V shape; the total number of teeth of the armature teeth and the fault-tolerant teeth is 20, and the number of poles of the permanent magnet is 18; because the stator adopts the single-layer concentrated winding, the magnetic resistance of a direct-axis magnetic circuit of the motor is greatly reduced, so that the salient pole rate of the motor is reduced, and the quadrature-axis and direct-axis inductances are approximately equal.

Fig. 2 is a proposed control method of a five-phase permanent magnet fault-tolerant motor without a position sensor, compared with the control method of a traditional sliding-mode observer without a position sensor shown in fig. 3, the control method of the five-phase permanent magnet fault-tolerant motor without a position sensor omits a coordinate transformation link, uses a hyperbolic function shown in fig. 4 as a sliding-mode variable structure function, removes a low-pass filter link and a phase compensation link, and simultaneously constructs a general phase-locked loop to improve estimation accuracy. The method for controlling the position-free sensor of the five-phase permanent magnet fault-tolerant motor comprises the following specific implementation steps:

step 1) establishing any two-phase mathematical model of the five-phase permanent magnet fault-tolerant motor based on the back electromotive force.

The voltage equation of any two phases of the five-phase permanent magnet fault-tolerant motor is expressed as

In the formula, R_sAnd L_sRespectively a stator resistor and an inductor; x, y ∈ 1,2, …, 5; u. of_xAnd u_yThe x phase voltage and the y phase voltage; i.e. i_xAnd i_yThe x-phase current and the y-phase current; e.g. of the type_xAnd e_yIs the opposite potential of the x phase and the y phase and is expressed as

Wherein E is_m＝ω_eγ_e；γ_eAnd theta_eBack emf coefficient and rotor position electrical angle, respectively.

And 2) constructing a current state observer based on any two-phase signals by using a hyperbolic function to acquire corresponding opposite potentials.

2.1) selecting a sliding mode variable structure function.

The expression (1) can be expressed by using a hyperbolic function as a sliding mode variable structure function

Wherein the content of the first and second substances,is the difference between the estimated current and the actual current; λ is the sliding mode coefficient;andis a hyperbolic function expressed as:

wherein a is a real number greater than zero and can be adjusted according to actual conditions.

2.2) constructing a current state observer based on any two-phase signals.

Subtracting the formula (1) from the formula (3) can obtain a current state observer based on any two-phase signals:

in this observer, the magnitude of the independent variable is defined when the boundary layer H is 0.99. As shown in FIG. 3, adjusting the value of a can effectively adjust the size of the boundary layer, thereby improving the counter potential harmonic content. By increasing the value a, the high-frequency harmonic of the observer can be effectively reduced, and the harmonic content of the observed counter electromotive force is greatly reduced, so that the constructed observer does not need a low-pass filter, a rotor position error compensation link can be omitted, and the construction of the universal PLL in the step 3 can be simplified.

2.3) analyzing the stability condition of the observer according to the existence and stability condition of the sliding mode motion.

According to the existence and stability conditions of sliding mode movement, the premise that the rotor position of the motor can be smoothly estimated is that:

namely:

then:

because the value of the hyperbolic function is less than 1, compared with the traditional sliding mode observer, the sliding mode coefficient value of the invention is larger.

And 3) constructing a universal phase-locked loop (PLL), inputting the two normal opposite potentials into a universal PLL module, and calculating to obtain the rotating speed of the motor and the position of the rotor.

In the conventional sliding-mode observer, the estimated back-emf of the two-phase stationary coordinate system is orthogonal, whereas the two-phase estimated back-emf of the present invention is not orthogonal; and, a phase delay will be caused due to the use of the low pass filter. Therefore, the present invention constructs a general PLL without phase compensation to acquire motor speed and rotor position information. A general PLL without phase compensation is shown in fig. 5, which includes a phase detector, a loop filter, and a voltage controlled oscillator.

Estimating back emf based on equation (2) and rotor position rangeIt must satisfy:

thus, it is possible to obtain:

according to fig. 5, the phase error of the phase detector is represented as:

from equations (10) and (11), the output Δ e of the phase detector is the estimated rotor position error. The estimated rotor position error delta e in the formula (11) is processed by a loop filter to obtain the estimated rotating speed informationMeanwhile, the delta e can be used for obtaining the position information of the rotor through a loop filter and a voltage-controlled oscillator

FIG. 6 shows the simulation results of the estimated back emf for different values of the adjustment coefficient a when the motor is operated at 300 r/min. The harmonic contents were found to be 12.3%, 8.7%, 4.4% and 1.6% for a ═ 0.2, 0.1, 0.05 and 0.01, respectively. Therefore, as the tuning coefficient a increases, THD decreases, which will help reduce system chatter. However, the back emf magnitude is estimated to be decreasing. It is worth noting that when a reaches a certain value, the estimated back emf magnitude and THD will not change. In order to ensure good dynamic and steady-state performance, a is 0.01. In addition, fig. 6(a) and (b) estimate the back emf for the BC phase, while fig. 6(c) and (d) estimate the back emf for the AC phase, demonstrating that any two phases of normal back emf can be used to estimate the rotor position, validating the feasibility of the proposed algorithm.

In summary, the invention discloses a position sensorless control method for a five-phase permanent magnet fault-tolerant motor, which comprises the steps of firstly, establishing any two-phase mathematical model of the five-phase permanent magnet fault-tolerant motor based on back electromotive force; secondly, constructing a current state observer based on any two-phase signals by using a hyperbolic function to obtain corresponding opposite potentials; and finally, constructing a universal phase-locked loop (PLL), inputting the two normal opposite potentials into a universal PLL module, and calculating to obtain the motor rotating speed and the rotor position. The control method has small calculation amount of algorithm, is simple and easy to realize, can effectively inhibit high-frequency buffeting in the system, solves the problem of phase delay and improves the estimation precision of the rotor position; in addition, coordinate transformation is omitted, any two-phase mathematical model of the five-phase permanent magnet fault-tolerant motor based on the back electromotive force is constructed to obtain the position information of the rotor, the robustness of the system is improved, and the motor has good tracking capability under a fault mode and parameter change disturbance.

The above embodiments are only used for illustrating the design idea and features of the present invention, and the purpose of the present invention is to enable those skilled in the art to understand the content of the present invention and implement the present invention accordingly, and the protection scope of the present invention is not limited to the above embodiments. In the description herein, references to the description of the term "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples" or the like mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. While embodiments of the invention have been shown and described, it will be understood by those of ordinary skill in the art that: all equivalent changes and modifications made in accordance with the principles and concepts disclosed herein are intended to be included within the scope of the present invention.