KR20230174087A - Control method for permanent magnet synchronous motor having double rotors structure - Google Patents

Abstract

The present invention is a dual-rotor structure permanent magnet synchronous motor including a permanent magnet ring, by offsetting the magnetic interference component that is inevitably generated as the torque of the stator is transmitted to the inner rotor and the outer rotor by forward compensation, This relates to a control method for a permanent magnet synchronous motor with a dual-rotor structure that minimizes speed and torque oscillations in transient states by suppressing resonance caused by load fluctuations. The stator is located at the outermost part. , an inner rotor is located at the innermost part, an outer rotor composed of a pole piece is located between the stator and the inner rotor, and a permanent magnet ring is located between the stator and the outer rotor to control the speed of the synchronous motor. A method of controlling a permanent magnet synchronous motor having a dual rotor structure, comprising: (a) calculating an error by subtracting the current speed of the inner rotor from a speed command for the inner rotor; (b) generating a torque command of the stator by proportionally integrating the error of step (a); (c) calculating a magnetic interference component generated by the torque generated in the stator with respect to the inner rotor and the outer rotor; and (d) forward-compensating the torque command by subtracting the magnetic interference component from the torque command of the stator.

Description

Control method of permanent magnet synchronous motor with double rotor structure {CONTROL METHOD FOR PERMANENT MAGNET SYNCHRONOUS MOTOR HAVING DOUBLE ROTORS STRUCTURE}

The present invention controls a permanent magnet synchronous motor having a double rotor structure of the PDD (Pseudo Direct Drive) type in which an outer rotor composed of pole pieces is located between the stator and the inner rotor and a permanent magnet ring is disposed inside the stator. This relates to a method for controlling a permanent magnet synchronous motor with a dual-rotor structure that can suppress speed and torque oscillations in transient states.

In general, drive systems for railway vehicles use permanent magnet synchronous motors as a power source. Conventionally, permanent magnet synchronous motors with a single-rotor structure were used, but recently, attempts to apply permanent magnet synchronous motors with a dual-rotor structure are increasing to increase power transmission efficiency.

A permanent magnet synchronous motor with a dual-rotor structure combining a magnetic gear and a PMSM (Permanent Magnet Synchronous Motor) has high torque output while occupying a smaller space than existing permanent magnets.

Figure 1 is an exploded perspective view illustrating a conventional permanent magnet synchronous motor with a dual-rotor structure. Referring to FIG. 1, in a dual rotor permanent magnet synchronous motor, the stator 100 is located on the outermost side, and the inner rotor 300 including permanent magnets 310 is located on the innermost side. A coil 120 is wound around the slot 110 provided in the stator 100. An outer rotor 200 composed of a pole piece is located between the stator 100 and the inner rotor 300.

In the shown dual-rotor permanent magnet motor, the number of pole pairs of the inner rotor 300 and the outer rotor 200 must be designed to be the same in order to generate a magnetic flux modulation effect. Nevertheless, as the torque generated from the stator 100 is transmitted simultaneously and in parallel according to the pole ratio of each rotor, when controlling the speed of the electric motor, the speed change of one rotor due to the change in load torque causes the other rotor to change. will affect. That is, speed control of a conventional permanent magnet synchronous motor with a dual-rotor structure means controlling the relative speeds of the inner rotor 300 and the outer rotor 200. Because of this, there is a problem that speed and torque oscillations occur in transient states when controlling the electric motor.

Republic of Korea Patent Publication No. 10-2021-0059235 Republic of Korea Patent Publication No. 10-2006-0022376

The present invention relates to a method for stably controlling a permanent magnet synchronous motor with a dual rotor structure including a permanent magnet ring. The magnetic interference component that is inevitably generated as the torque of the stator is transmitted to the inner rotor and the outer rotor Provides a control method for a permanent magnet synchronous motor with a dual-rotor structure that minimizes speed and torque oscillations in transient states by suppressing the phenomenon of resonance caused by load fluctuations in railway vehicles by offsetting them with forward compensation. There is a purpose to it.

In the control method of a permanent magnet synchronous motor with a dual rotor structure according to an embodiment of the present invention, a stator is located on the outermost side, an inner rotor is located on the innermost side, and magnetic poles are located between the stator and the inner rotor. In the control method of a permanent magnet synchronous motor having a double rotor structure for controlling the speed of a synchronous motor in which an outer rotor composed of pieces is located and a permanent magnet ring is located between the stator and the outer rotor, (a ) calculating an error by subtracting the current speed of the inner rotor from the speed command for the inner rotor; (b) generating a torque command of the stator by proportionally integrating the error of step (a); (c) calculating a magnetic interference component generated by the torque generated in the stator with respect to the inner rotor and the outer rotor; and (d) forward-compensating the torque command by subtracting the magnetic interference component from the torque command of the stator.

In the control method of a permanent magnet synchronous motor with a dual rotor structure according to another embodiment of the present invention, step (c) calculates the magnetic interference component through Equation 11 below.

[Equation 11]

은 상기 자기적 간섭성분이고,

은 상기 내측 회전자의 극쌍수이고,

은 상기 외측 회전자의 극쌍수이고,

는 상기 내측 회전자에서 상기 외측 회전자로 전달할 수 있는 최대 토크이고,

는 상기 내측 회전자와 상기 외측 회전자의 전기각 차이이다.here

is the magnetic interference component,

is the pole pair number of the inner rotor,

is the pole pair number of the outer rotor,

is the maximum torque that can be transmitted from the inner rotor to the outer rotor,

is the electrical angle difference between the inner rotor and the outer rotor.

In a method of controlling a permanent magnet synchronous motor with a dual rotor structure according to another embodiment of the present invention, the electrical angle difference between the inner rotor and the outer rotor is calculated through Equation 2 below.

[Equation 2]

은 내측 회전자의 속도이고,

은 외측 회전자의 속도이다.here,

is the speed of the inner rotor,

is the speed of the outer rotor.

In a method of controlling a permanent magnet synchronous motor having a dual rotor structure according to another embodiment of the present invention, the speed of the inner rotor and the speed of the outer rotor are obtained by measurement.

In a method of controlling a permanent magnet synchronous motor having a dual rotor structure according to another embodiment of the present invention, the speed of the inner rotor is obtained by measurement, and the speed of the outer rotor is determined by estimation.

In the control method of a permanent magnet synchronous motor with a dual rotor structure according to another embodiment of the present invention, estimating the speed of the outer rotor includes (i) applying an estimated current to a coil wound on the stator; Forcefully starting the synchronous motor; (ii) estimating the resultant electromotive force of each phase of the coil; and (iii) estimating the position error of the outer rotor using the combined electromotive force; and (iv) estimating the speed of the outer rotor based on the position error.

According to the control method of a permanent magnet synchronous motor with a dual rotor structure of the present invention, the current speed of the inner rotor and the current speed of the outer rotor are measured for a permanent magnet synchronous motor with a dual rotor structure including a permanent magnet ring. And, by using this measured value to offset the magnetic interference component applied to the two rotors with forward compensation, it is possible to suppress the phenomenon of resonance caused by load fluctuations in railway vehicles and minimize speed and torque vibration in transient states. This has the effect of simplifying the configuration of the control system of the electric motor and improving the stability, durability, and riding comfort of the railway vehicle.

Figure 1 is an exploded perspective view illustrating a conventional permanent magnet synchronous motor with a dual-rotor structure;
Figure 2 is a cross-sectional view illustrating a permanent magnet synchronous motor with a PDD type dual-rotor structure;
Figure 3 is a block diagram mechanically modeling the synchronous motor of Figure 2 by applying a magnetic spring;
Figure 4 is a block diagram modeling the control process of a permanent magnet synchronous motor with a dual rotor structure according to the present invention using the modeling of Figure 3 and Equation 1;
Figure 5 is a speed controller block diagram before applying forward compensation according to the present invention;
Figure 6 is a speed controller block diagram after applying forward compensation according to the present invention;
Figure 7 is a block diagram simplifying the model of Figure 4 according to the speed control method of Figure 6;
Figure 8 is a waveform diagram showing the results of simulation analysis before applying forward compensation according to the present invention, and
Figure 9 is a waveform diagram showing the results of simulation analysis after applying forward compensation according to the present invention.

Hereinafter, specific embodiments according to the present invention will be described with reference to the attached drawings. However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all changes, equivalents, and substitutes included in the spirit and technical scope of the present invention.

Throughout the specification, parts having similar structures and operations are given the same reference numerals. Additionally, the drawings attached to the present invention are for convenience of explanation, and the shape and relative scale may be exaggerated or omitted.

In describing the embodiments in detail, redundant descriptions or descriptions of techniques that are obvious in the field have been omitted. Additionally, in the following description, when a part is said to “include” other components, this means that it may include additional components in addition to the components described, unless specifically stated to the contrary.

In addition, terms such as "unit", "unit", and "module" used in the specification refer to a unit that processes at least one function or operation, which may be implemented through hardware or software or a combination of hardware and software. You can. Additionally, when a part is said to be electrically connected to another part, this includes not only the case where it is directly connected, but also the case where it is connected with another component in between.

Terms containing ordinal numbers, such as first, second, etc., may be used to describe various components, but the components are not limited by the terms. The above terms are used only for the purpose of distinguishing one component from another. For example, the second component may be referred to as the first component without departing from the scope of the present invention, and similarly, the first component may also be referred to as the second component.

The control method of a permanent magnet synchronous motor with a dual rotor structure of the present invention is a dual rotor permanent magnet synchronous motor (DR-PMSM, with magnetic coupling type 2) rather than the magnetic coupling type 1 synchronous motor exemplified as background technology. This is a control method targeting a Dual-Rotor Permanent Magnet Synchronous Motor (PDD) type DR-PMSM, for example. Before explaining the present invention in detail, the PDD type DR-PMSM structure will be briefly described with reference to FIG. 2.

Figure 2 is a cross-sectional view illustrating a permanent magnet synchronous motor with a PDD type dual rotor structure. Referring to FIG. 2, the DR-PMSM, which is the control target, has a stator 100 located on the outermost side, and an inner rotor 300 including a permanent magnet 310 is located on the innermost side. A coil 120 is wound around the slot 110 provided in the stator 100. An outer rotor 200 composed of a pole piece is located between the stator 100 and the inner rotor 300. Up to this point, it is the same as DR-PMSM of magnetic coupling type 1. The difference is that a permanent magnet ring 210 is located between the stator 100 and the outer rotor 200.

The synchronous motor of magnetic coupling type 2 illustrated in FIG. 2 is designed to have the same number of pole pairs of the stator 100 and the number of pole pairs of the inner rotor 300, so that the rotating magnetic field generated from the stator 100 and the inner rotor ( 300) can rotate synchronously. At this time, the magnetic flux of the inner rotor 300 is modulated through the pole pieces. The modulated magnetic flux interacts with the permanent magnet ring 210 for harmonic components that can be synchronized. The permanent magnet ring 210 is fixed, and when the inner rotor 300 rotates, the outer rotor 200 rotates to synchronize the harmonics of the modulated magnetic flux.

The magnetic coupling type 2 synchronous motor has a better power factor than the magnetic coupling type 1 synchronous motor illustrated in the background technology due to the permanent magnet ring 210, and has higher efficiency and output than modulation devices using the magnetic flux modulation effect. It has high advantages.

Figure 3 is a block diagram mechanically modeling the synchronous motor of Figure 2 by applying a magnetic spring. Referring to FIG. 3, the rotation principle of the DR-PMSM to which the permanent magnet ring 210 is added can be represented by a torque transmission model between the inner rotor 300 and the outer rotor 200 to which the magnetic spring is added. Reference numeral 400 is a load connected to a synchronous motor.

[Equation 1]

[Equation 2]

은 외측 회전자의 토크이고,

는 내측 회전자에서 외측 회전자로 전달할 수 있는 최대 토크이고,

는 내측 회전자와 외측 회전자의 전기각 차이이고,

은 내측 회전자의 극쌍수이고,

은 내측 회전자의 속도이고,

은 외측 회전자의 극쌍수이고,

은 외측 회전자의 속도이다.Equation 1 represents the torque transmission characteristics of the magnetic spring, and Equation 2 represents the electric angle difference in Equation 1. here,

is the torque of the outer rotor,

is the maximum torque that can be transmitted from the inner rotor to the outer rotor,

is the difference in electrical angle between the inner and outer rotors,

is the pole dual number of the inner rotor,

is the speed of the inner rotor,

is the pole dual number of the outer rotor,

is the speed of the outer rotor.

Through Equation 1 and Equation 2, it can be seen that the torque transmission characteristics of the magnetic spring are determined by the electric angle difference between the inner rotor and the outer rotor.

Figure 4 is a block diagram modeling the control process of a permanent magnet synchronous motor with a dual rotor structure according to the present invention using the modeling of Figure 3 and Equation 1.

)에 제어 상수(

, 410)를 승산하여 고정자(100)에 대한 토크 지령(

)이 출력된다. 감산부(420)는 토크 지령(

)에서 후술하는 자기적 간섭성분(

)을 감산하며, 내측 회전자 전달요소(430)를 통해 내측 회전자의 속도(

)가 결정된다. 내측 회전자 전달요소(430)의 전달함수는 관성모멘트(

)를 미분한 값과 마찰계수(

)의 합의 역수로 나타낼 수 있다.Referring to Figure 4, the current command (

) to the control constant (

, 410) is multiplied to obtain the torque command for the stator 100 (

) is output. The subtraction unit 420 receives a torque command (

), the magnetic interference component described later (

) is subtracted, and the speed of the inner rotor (

) is determined. The transfer function of the inner rotor transfer element 430 is the moment of inertia (

) and the friction coefficient (

) can be expressed as the reciprocal of the sum of

)에 내측 회전자의 극쌍수(

, 440)를 승산한 값에서 외측 회전자의 속도(

)에 외측 회전자의 극쌍수(

, 500)를 승산한 값을 감산한다. 이 감산 결과에 토크 상수 전달요소(460)의 전달함수를 승산한 경과 외측 회전자의 토크 지령(

)이 출력된다. 토크 상수 전달요소(460)에서

는 마그네틱 스프링으로 표현되는 회전자간 토크 전달 제어 상수를 나타내며,

는 라플라스 연산자를 나타낸다. 외측 회전자의 토크 지령(

)에 내측 회전자와 외측 회전자의 극쌍수 비(

, 470)를 승산한 값이 피드백 제어의 오차 연산을 위해 제공된다.Subtractor 450 is the speed of the inner rotor (

) to the number of pole pairs of the inner rotor (

, 440), the speed of the outer rotor (

) to the number of pole pairs of the outer rotor (

, 500) is multiplied and the value is subtracted. This subtraction result is multiplied by the transfer function of the torque constant transfer element 460, resulting in the torque command of the outer rotor (

) is output. In the torque constant transfer element 460

represents the torque transfer control constant between rotors expressed by magnetic springs,

represents the Laplace operator. Torque command of the outer rotor (

) to the ratio of pole pairs of the inner and outer rotors (

, 470) is provided for error calculation of feedback control.

)에서 부하 토크(

)를 감산하고, 그 결과가 외측 회전자 전달요소(490)를 통해 출력되어 외측 회전자의 속도(

)가 결정된다. 외측 회전자 전달요소(490)의 전달함수는 관성모멘트(

)를 미분한 값과 마찰계수(

)의 합의 역수로 나타낼 수 있다.The subtraction unit 480 receives the torque command of the outer rotor (

) at load torque (

) is subtracted, and the result is output through the outer rotor transmission element 490 to speed the outer rotor (

) is determined. The transfer function of the outer rotor transfer element 490 is the moment of inertia (

) and the friction coefficient (

) can be expressed as the reciprocal of the sum of

)를 지령으로 하여 내측 회전자(300)가 회전될 때, 도 3의 모델에서 마그네틱 스프링이 비틀어지면서 외측 회전자(200)로 토크가 전달된다. 이와 동시에 마그네틱 스프링의 비틀림 토크가 내측 회전자(300)에도 되돌아오는 자기적 간섭성분이 발생한다.At this time, the stator torque (

When the inner rotor 300 is rotated with ) as a command, the magnetic spring is twisted in the model of FIG. 3 and torque is transmitted to the outer rotor 200. At the same time, a magnetic interference component is generated in which the torsional torque of the magnetic spring is returned to the inner rotor 300.

As shown, when modeling the torque transfer process between the inner rotor 300 and the outer rotor 200 using a magnetic spring, a resonance point occurs due to the nonlinear Sin component and magnetic interference component of the magnetic spring. do. The resonance point can be confirmed through the transfer function of the modeling illustrated in FIG. 4.

[Equation 3]

[Equation 4]

에 대한 각 회전자 속도의 전달함수로 나타내면 다음의 수학식 5 및 6으로 나타낼 수 있다.Equation 3 and Equation 4 represent the transfer functions of the inner rotor speed and outer rotor speed with respect to the stator torque and load torque, respectively. Using the principle of superposition, the above two equations

When expressed as a transfer function of each rotor speed for , it can be expressed as the following equations 5 and 6.

[Equation 5]

[Equation 6]

In other words, it can be confirmed that there is a zero point in Equation 5, which is the transfer function of the inner rotor speed for the torque generated from the stator, and that there is no zero point in Equation 6, which is the transfer function of the outer rotor speed. . Here, zero represents the anti-resonance point, which means that there is a frequency band in which the inner rotor cannot rotate. This is a factor that degrades operating characteristics, so it is necessary to avoid this area when selecting the controller bandwidth.

The poles in Equations 5 and 6 refer to the resonance frequency, and it can be confirmed that the resonance frequencies occurring inside and outside are the same. If the anti-resonance frequency and resonance frequency are expressed as formulas through the zero and pole of Equations 5 and 6, they can be expressed as the following Equations 7 and 8.

[Equation 7]

[Equation 8]

는 상기한 반공진 주파수이고,

은 상기한 공진 주파수이다. 수학식 7과 8을 통해 반공진 주파수와 공진 주파수는

와 각 회전자의 관성모멘트에 영향을 받는 것을 알 수 있다. 특히 부하의 영향으로 외측 회전자의 관성모멘트가 증가할 경우 공진 주파수는 낮은 주파수로 이동할 것임을 알 수 있다.here,

is the anti-resonance frequency described above,

is the above-mentioned resonance frequency. Through equations 7 and 8, the anti-resonance frequency and resonance frequency are

It can be seen that it is affected by the moment of inertia of each rotor. In particular, it can be seen that if the moment of inertia of the outer rotor increases due to the influence of the load, the resonance frequency will move to a lower frequency.

의 전달함수를 구한 것과 같이 중첩의 원리를 이용하여 부하토크

에 대한 각 회전자 속도의 전달함수를 도출할 수 있다. 도출된 전달함수는 수학식 9와 10으로 나타낼 수 있다.In equations 3 and 4

The load torque is calculated using the principle of superposition as the transfer function of

The transfer function of each rotor speed can be derived. The derived transfer function can be expressed as Equations 9 and 10.

[Equation 9]

[Equation 10]

와 마찬가지로 부하 토크(

)의 변동으로 각 회전자에 공진이 발생하는 것을 알 수 있다. 철도차량에서 부하변동으로 공진이 발생할 경우 차량에 떨림이 발생하고 철도차량의 안정성, 내구성 및 승차감에 문제를 발생하므로 반드시 해결되어야 하는 문제이다.Through equations 9 and 10

As with load torque (

It can be seen that resonance occurs in each rotor due to the variation of ). When resonance occurs in a railway vehicle due to load changes, vibration occurs in the vehicle and problems arise in the stability, durability, and ride comfort of the railway vehicle, so it is a problem that must be solved.

)가 감산부(480), 외측 회전자 전달요소(490), 감산부(450), 토크 상수 전달요소(460), 감산부(420)를 거쳐 내측 회전자 전달요소(430)에 이르는 것을 확인할 수 있다. 즉, 부하 토크의 변화가 내측 회전자에 영향을 미치므로, 마그네틱 스프링에 의해 발생한 공진이 상단의 폐루프를 통해 내측 회전자(300)에 간섭을 준다. 이러한 자기적 간섭성분은 고정자(100)의 토크가 내측 회전자를 제어하는데 방해 요소가 되므로 상쇄시킬 필요가 있다.In the present invention, forward torque compensation control is implemented to reduce resonance phenomenon. Referring to Figure 4, the load torque (

) is confirmed to reach the inner rotor transmission element 430 via the subtraction unit 480, the outer rotor transmission element 490, the subtraction unit 450, the torque constant transmission element 460, and the subtraction unit 420. You can. In other words, since the change in load torque affects the inner rotor, the resonance generated by the magnetic spring interferes with the inner rotor 300 through the closed loop at the top. These magnetic interference components need to be canceled because they become a hindrance to the torque of the stator 100 controlling the inner rotor.

[Equation 11]

,

,

는 전동기의 파라미터이며 운전중 변하지 않는다고 가정한다.

는 수학식 2에서와 같이 내측 회전자와 외측 회전자의 속도에 의해 결정된다. 따라서 내측 회전자와 외측 회전자의 속도를 알 수 있다면 자기적 간섭성분을 계산할 수 있다.The magnetic interference component can be calculated through Equation 11. here

,

,

is a parameter of the motor and is assumed not to change during operation.

is determined by the speed of the inner rotor and the outer rotor as shown in Equation 2. Therefore, if the speeds of the inner and outer rotors are known, the magnetic interference component can be calculated.

Figure 5 is a speed controller block diagram without considering the magnetic interference component of Equation 11, that is, before applying forward compensation. Figure 6 is a block diagram of a speed controller considering magnetic interference components, that is, after applying forward compensation.

)에서 내측 회전자의 현재 속도(

)를 감산하여 오차를 연산한다. 속도 제어기(520)는 오차 검출 결과를 비례적분하여 고정자의 토크 지령(

)을 생성한다. 이와 같은 일반적인 속도 제어를 실시할 경우 도 4에 도시된 바와 같이 자기적 간섭성분이 내측 회전자의 제어에 영향을 미치게 되며, 후술하는 모의해석 결과에서와 같이 부하 변동 시에 속도의 오버슈트나 진동이 발생될 수 있다.Referring to Figure 5, the first subtractor 510 provides a speed command (

) at the current speed of the inner rotor (

) is subtracted to calculate the error. The speed controller 520 proportionally integrates the error detection result to provide the stator's torque command (

) is created. When such general speed control is implemented, as shown in Figure 4, magnetic interference components affect the control of the inner rotor, and as shown in the simulation analysis results described later, speed overshoot or vibration occurs when the load changes. This may occur.

)에서 수학식 11을 통해 연산된 자기적 간섭성분(

)을 감산하여 토크 지령을 전향 보상하고 있다.Referring to FIG. 6, compared to FIG. 5, the second subtractor 530 receives the stator's torque command (

), the magnetic interference component calculated through Equation 11 (

) is subtracted to forward compensate the torque command.

)을 연산하고, 이를 속도 제어기(520)의 출력측에 보상함으로써, 자기적 간섭성분을 상쇄할 수 있다.As an example, after measuring the speed of the inner rotor and the speed of the outer rotor, the magnetic interference component (

) is calculated and compensated for on the output side of the speed controller 520, thereby canceling out the magnetic interference component.

)을 연산하고, 이를 속도 제어기(520)의 출력측에 보상함으로써, 자기적 간섭성분을 상쇄할 수 있다.As another example, the speed of the inner rotor can be measured through a sensor, and the speed of the outer rotor can be estimated through sensorless logic. And, from the difference in electric angles of the two rotors, the magnetic interference component (

) is calculated and compensated for on the output side of the speed controller 520, thereby canceling out the magnetic interference component.

Estimating the speed of the outer rotor can be performed in the following way. For example, a synchronous motor is forced to start by applying an estimated current to a coil wound around the stator. Then, estimate the combined electromotive force of each phase of the coil. The position error for the initial position of the outer rotor can be estimated from the result of the estimation of the combined electromotive force. Finally, the speed of the outer rotor is estimated based on the position error.

)와 내측 회전자 속도(

)의 전달함수는 1차식으로 나타낼 수 있으며, 1차 선형제어기인 PI 제어기를 이용하여 쉽게 제어할 수 있게 된다.FIG. 7 is a simplified block diagram of the control model of FIG. 4 according to the speed control method of FIG. 6. That is, according to forward compensation as shown in FIG. 6, modeling of a dual-rotor permanent magnet synchronous motor as shown in FIG. 7 can be simplified by removing the loop at the top. If the magnetic interference component is omitted, the stator torque (

) and inner rotor speed (

)'s transfer function can be expressed as a linear equation and can be easily controlled using a PI controller, a first-order linear controller.

Figure 8 is a waveform diagram showing the simulation analysis results before applying forward compensation as shown in Figure 5, and Figure 9 is a waveform diagram showing the simulation analysis results after applying forward compensation as shown in Figure 6. In both simulation analyses, the same 1kw magnetic coupling type 2 DR-PMSM was targeted, and each parameter of the motor was applied as shown in Table 1 below.

[Table 1]

The switching frequency was selected at 8kHz, and the bandwidth of the current controller was selected at 320kHz, which is 1/25 of the switching frequency.

Referring to FIG. 8, it was confirmed that the speed of the outer rotor maintained vibration for 1-2 seconds at 0 seconds, 2 seconds, and 5 seconds when the load fluctuated. On the other hand, referring to Figure 9, when forward compensation is implemented, it was confirmed that the overshoot of the outer rotor speed was greatly reduced even when the load changed under the same conditions, and the vibration also quickly disappeared.

The invention disclosed above can be modified in various ways without damaging the basic idea. In other words, all of the above embodiments should be interpreted as illustrative and not limited. Therefore, the scope of protection of the present invention should be determined based on the attached claims, not the above-described embodiments, and if the components defined in the attached claims are replaced with equivalents, this should be considered to fall within the scope of protection of the present invention.

100: stator 110: slot
120: coil 200: outer rotor
210: permanent magnet ring 300: inner rotor
310: permanent magnet 400: load
510: first subtractor 520: speed controller
530: second subtractor

Claims (6)

A stator is located on the outermost side, an inner rotor is located on the innermost side, an outer rotor composed of a pole piece is located between the stator and the inner rotor, and a permanent magnet ring is located between the stator and the outer rotor. In the control method of a permanent magnet synchronous motor having a dual rotor structure for controlling the speed of a positioned synchronous motor,
(a) calculating an error by subtracting the current speed of the inner rotor from the speed command for the inner rotor;
(b) generating a torque command of the stator by proportionally integrating the error of step (a);
(c) calculating a magnetic interference component generated by the torque generated in the stator with respect to the inner rotor and the outer rotor; and
(d) Forward compensating the torque command by subtracting the magnetic interference component from the torque command of the stator.
A control method of a permanent magnet synchronous motor having a dual rotor structure including.
According to paragraph 1,
The step (c) is a control method of a permanent magnet synchronous motor with a dual rotor structure in which the magnetic interference component is calculated through Equation 11 below.
[Equation 11]

here

is the magnetic interference component,

is the pole pair number of the inner rotor,

is the pole pair number of the outer rotor,

is the maximum torque that can be transmitted from the inner rotor to the outer rotor,

is the electrical angle difference between the inner rotor and the outer rotor.
According to paragraph 2,
A control method for a permanent magnet synchronous motor having a dual rotor structure in which the electrical angle difference between the inner rotor and the outer rotor is calculated using Equation 2 below.
[Equation 2]

here,

is the speed of the inner rotor,

is the speed of the outer rotor.
According to paragraph 3,
A method of controlling a permanent magnet synchronous motor having a dual rotor structure in which the speed of the inner rotor and the speed of the outer rotor are obtained by measurement.
According to paragraph 3,
A method of controlling a permanent magnet synchronous motor having a dual rotor structure in which the speed of the inner rotor is obtained by measurement and the speed of the outer rotor is determined by estimation.
According to clause 5,
To estimate the speed of the outer rotor,
(i) forcibly starting the synchronous motor by applying an estimated current to a coil wound around the stator;
(ii) estimating the resultant electromotive force of each phase of the coil; and
(iii) estimating the position error of the outer rotor using the combined electromotive force; and
(iv) estimating the speed of the outer rotor based on the position error
A control method of a permanent magnet synchronous motor having a dual rotor structure determined including.

Images