Variable speed power unit and control method

Abstract

This variable-speed power device is provided with: a synchronous machine having a stator provided with an armature winding to form an armature, a first rotor having magnetic poles, and a second rotor provided between the first rotor and the stator to drive a load; an induced voltage angle estimation unit for estimating the electrical angle of an induced voltage generated in the armature on the basis of a first angle of the first rotor and a second angle of the second rotor; and, an electric power converter for adjusting the frequency of electric power for driving the synchronous machine on the basis of the estimated electrical angle of the induced voltage.

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE The present disclosure relates to variable speed power plants and control methods. This application claims priority to Patent Application No. 2021-171614, filed in Japan on October 20, 2021, the contents of which are incorporated herein by reference. [Background technology]

[0002] 23 shows an example of a variable speed power unit 9A using a general synchronous machine 90A. The variable speed power unit 9A is composed of a synchronous machine 90A and a power converter 91 (inverter) for varying the speed. The synchronous machine 90A has a stator 901A and a rotor 902A.

[0003] Because the torque generated by the synchronous machine 90A is limited, a mechanical reducer 92 (gear) is generally used to drive a heavy load. The reducer 92 is connected to the output shaft 94 of the synchronous machine 90A and reduces the rotational speed of the synchronous machine 90A before transmitting the power to the load. However, because the reducer 92 transmits power through contact between gears, maintenance of the sliding parts is required. For this reason, variable speed power units that do not use a reducer are considered, such as those using a synchronous machine with two rotors, a first rotor and a second rotor. Synchronous machines with two rotors are called magnetic-geared motors. Magnetic-geared motors transmit power without contact between the rotors using magnetic force, eliminating the need for maintenance of sliding parts. Furthermore, magnetic-geared motors have the advantage of being smaller and lighter because they require fewer parts than those using a reducer.

[0004] 24 shows an example of a variable speed power unit 9B using a magnetic-geared motor 90B. The variable speed power unit 9B is composed of a magnetic-geared motor 90B and a power converter 91. The magnetic-geared motor 90B has a stator 901B, a first rotor 902B, and a second rotor 903B provided between the stator 901B and the first rotor 902B. The first rotor 902B may be connected to another load or power source via an output shaft 94A.

[0005] The power that drives the synchronous machine 90A and the magnetic-geared motor 90B is generally three-phase AC. The rotation speed of a general synchronous machine 90A is synchronized with the frequency of the driving power. When the frequency of the power is changed, the rotation speed of the synchronous machine 90A also changes in synchronization with it, and the speed of the load also changes. Therefore, if the relationship between the frequency of the driving power and the speed of the load is determined in advance, the frequency can be adjusted to operate the load at a desired speed. The magnetic-geared motor 90B is the same as the general synchronous machine 90A, and the speed of the load can be changed by adjusting the frequency of the driving power.

[0006] In a typical synchronous machine 90A or magnetic-geared motor 90B, loss of synchronism may occur when the load is excessive. As mentioned earlier, the synchronous machine 90A has an upper limit to the torque it can output. If the load continuously exceeds this upper torque limit, the rotation of the synchronous machine 90A will lag behind the power, resulting in loss of synchronism. In a loss of synchronism state, the rotation speed of the synchronous machine 90A is unrelated to the frequency of the driving power, making it impossible to move the load at the desired speed. Furthermore, loss of synchronism can cause large vibrations and noise in the machine that serves as the load, potentially damaging the machine. Therefore, it is important to prevent loss of synchronism when operating the synchronous machine 90A or magnetic-geared motor 90B.

[0007] In a typical synchronous machine 90A, loss of synchronism is prevented by synchronizing the voltage of the driving power with the electrical angle of the induced voltage generated in the armature (armature winding of stator 901A) as the magnetic poles of rotor 902A rotate. More specifically, the phase of the voltage on power line 93 is adjusted so that the difference between the electrical angle of the induced voltage and the angle of the voltage of the driving power, i.e., the electrical angle, does not exceed ±90 degrees. As a result, the phase or frequency of the power output by power converter 91 reflects the rotation angle or rotation speed of rotor 902A. For example, if the load is excessive and the rotation of rotor 902A is delayed, the drive frequency can be lowered to prevent loss of synchronism.

[0008] The induced voltage is the time derivative of the magnetic flux linking the armature. Because the interlinkage magnetic flux rotates with the rotor 902A, knowing the angle of the rotor 902A allows the interlinkage magnetic flux and its differentiated induced voltage to be determined. A typical synchronous machine 90A has a single rotor 902A, so knowing the angle of the rotor 902A is sufficient to determine the induced voltage generated in the armature. Because the rotor 902A is connected to the output shaft 94, a rotation angle sensor 95 attached to the output shaft 94 can measure the angle of the output shaft 94, i.e., the angle of the rotor 902A. For example, Patent Document 1 describes a technology that uses a rotation angle sensor to measure the angle of the output shaft and commutate AC power that drives the motor in synchronization with the rotation of the output shaft. In this way, the frequency of the power flowing through the power line is synchronized with the output shaft. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] International Publication No. 2015 / 186714 Summary of the Invention [Problem to be solved by the invention]

[0010] Magnetic-geared motor 90B has a second rotor 903B in addition to a first rotor 902B corresponding to rotor 902A of synchronous machine 90A. For example, Patent Document 1 further describes a magnetic-geared motor having a first rotor (first rotor) and a second rotor (second rotor), which outputs power from the second rotor. That is, in the magnetic-geared motor described in Patent Document 1, the rotation angle sensor that measures the angle of the output shaft measures the angle of the second rotor.

[0011] In a magnetic-geared motor, the induced voltage generated in the armature depends not only on the angle of the second rotor but also on the angle of the first rotor. For this reason, the technology described in Patent Document 1 can cause errors by ignoring the influence of the first rotor. This can lead to loss of synchronization in situations where the induced voltage is determined more by the angle of the first rotor than by the angle of the second rotor.

[0012] The present disclosure has been made in view of the above-described problems, and provides a variable speed power unit and a control method that can suppress step-out of a synchronous machine. [Means for solving the problem]

[0013] According to one aspect of the present disclosure, a variable speed power unit includes a synchronous machine having a stator having an armature winding formed thereon to form an armature, a first rotor having magnetic poles, and a second rotor provided between the first rotor and the stator to drive a load; an induced voltage angle estimator that estimates the electrical angle of an induced voltage generated in the armature based on a first angle of the first rotor and a second angle of the second rotor; and a power converter that adjusts the frequency of power that drives the synchronous machine based on the estimated electrical angle of the induced voltage.

[0014] According to one aspect of the present disclosure, a variable speed power unit includes a synchronous machine having a stator with an armature winding provided thereon to form an armature, a first rotor having magnetic poles, and a second rotor provided between the first rotor and the stator, and a power converter that performs V / f control based on the electrical angle of the first rotor or the electrical angle of the second rotor, whichever has a larger absolute value of offset from the electrical angle of a voltage that drives the synchronous machine, and adjusts the frequency of the power that drives the synchronous machine.

[0015] According to one aspect of the present disclosure, a control method for a synchronous machine having a stator with an armature winding to form an armature, a first rotor having magnetic poles, and a second rotor provided between the first rotor and the stator to drive a load includes the steps of: estimating an electrical angle of an induced voltage generated in the armature based on a first angle of the first rotor and a second angle of the second rotor; and adjusting a frequency of power that drives the synchronous machine based on the estimated electrical angle of the induced voltage. [Effects of the Invention]

[0016] According to the variable speed power unit and control method of the present disclosure, it is possible to suppress step-out of a synchronous machine. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a diagram showing a functional configuration of a variable speed power unit according to a first embodiment of the present disclosure. [Figure 2] 1 is a cross-sectional view of a synchronous machine according to a first embodiment of the present disclosure. [Figure 3] FIG. 2 is a diagram for explaining the concept of operation of the power converter according to the first embodiment of the present disclosure. [Figure 4] FIG. 4 is a diagram showing the functional configuration of a variable speed power unit according to a second embodiment of the present disclosure. [Figure 5] FIG. 10 is a cross-sectional view of a first rotor according to a third embodiment of the present disclosure. [Figure 6] FIG. 10 is a cross-sectional view of a first rotor according to a fourth embodiment of the present disclosure. [Figure 7] FIG. 10 is a perspective view of a first rotor according to a fourth embodiment of the present disclosure. [Figure 8] FIG. 10 is a diagram showing the functional configuration of a variable speed power unit according to a fifth embodiment of the present disclosure. [Figure 9] FIG. 10 is a diagram showing the functional configuration of a variable speed power unit according to a sixth embodiment of the present disclosure. [Figure 10] FIG. 13 is a diagram showing the functional configuration of a variable speed power unit according to a seventh embodiment of the present disclosure. [Figure 11] FIG. 13 is a diagram showing the functional configuration of a variable speed power unit according to an eighth embodiment of the present disclosure. [Figure 12] FIG. 13 is a diagram illustrating a functional configuration of a power converter according to an eighth embodiment of the present disclosure. [Figure 13] FIG. 13 is a diagram showing the functional configuration of a variable speed power unit according to a ninth embodiment of the present disclosure. [Figure 14] FIG. 13 is a diagram illustrating a functional configuration of a power converter according to a ninth embodiment. [Figure 15] FIG. 13 is a diagram illustrating an example of an induced voltage vector according to a ninth embodiment of the present disclosure. [Figure 16] FIG. 22 is a diagram showing the functional configuration of a variable speed power unit according to a tenth embodiment of the present disclosure. [Figure 17] FIG. 23 is a diagram for explaining the operation of the power converter according to the tenth embodiment of the present disclosure. [Figure 18] FIG. 23 is a diagram showing an example of a load angle according to a tenth embodiment of the present disclosure. [Figure 19] FIG. 22 is a diagram showing the functional configuration of a variable speed power unit according to an eleventh embodiment of the present disclosure. [Figure 20] FIG. 23 is a diagram showing the functional configuration of a variable speed power unit according to a twelfth embodiment of the present disclosure. [Figure 21] FIG. 29 is a diagram illustrating a functional configuration of a power converter according to a twelfth embodiment of the present disclosure. [Figure 22] FIG. 1 is a diagram illustrating an example of a hardware configuration of devices that constitute a variable speed power unit according to at least one embodiment of the present disclosure. [Figure 23] FIG. 1 is a first diagram showing an example of a conventional variable speed power unit. [Figure 24] FIG. 2 is a second diagram showing an example of a conventional variable speed power unit. DETAILED DESCRIPTION OF THE INVENTION

[0018] First Embodiment A variable speed power unit 1 according to a first embodiment of the present disclosure will be described below with reference to the drawings.

[0019] (Functional configuration of variable speed power unit) FIG. 1 is a diagram showing the functional configuration of a variable speed power unit according to a first embodiment of the present disclosure. As shown in FIG. 1, the variable speed power unit 1 includes a synchronous machine 2, a control device 3, and a power converter 4.

[0020] The synchronous machine 2 is a magnetic-geared motor. A magnetic-geared motor also functions as a magnetic-geared generator. Therefore, the synchronous machine 2 according to this embodiment functions as both a motor and a generator. In the following, an example in which the synchronous machine 2 is used as a motor will be described.

[0021] FIG. 2 is a cross-sectional view of a synchronous machine according to a first embodiment of the present disclosure. As shown in FIGS. 1 and 2, the synchronous machine 2 has a stator 21, a first rotor 22, a second rotor 23, an output shaft 24, and an output shaft 24A.

[0022] The stator 21 is an annular structure surrounding the first rotor 22 and the second rotor 23. The stator 21 has a plurality of teeth 211 that protrude radially inward, each of which is provided with an armature winding 212, thereby forming an armature.

[0023] The first rotor 22 is a rotor that rotates around a rotation axis O. The first rotor 22 has a core 221 formed of a soft magnetic material and a plurality of magnetic poles 222. The magnetic poles 222 are, for example, permanent magnets. In the example of FIG. 2, the number of magnetic poles of the first rotor 22 is four, but this is not limited to this. In other embodiments, the number of magnetic poles of the first rotor 22 may be changed. The first rotor 22 is connected to another load or power via an output shaft 24A.

[0024] 2 shows a configuration in which permanent magnets are arranged to cover the entire outer circumferential surface of core 221 of first rotor 22, but this is not limiting. In other embodiments, first rotor 22 may be configured such that multiple magnetic poles (salient poles) protruding radially outward from the outer circumferential surface are integrally formed with core 221. In this case, first rotor 22 may not be provided with magnets or electromagnets. In still other embodiments, core 221 of first rotor 22 may be formed of a soft magnetic material such as a magnetic steel plate, and magnets may be arranged at intervals on the outer circumferential surface of core 221. In other words, instead of covering the entire outer circumferential surface of core 221 with magnets as in the example of FIG. 2, a soft magnetic material may be exposed between adjacent magnets (at the boundaries).

[0025] The second rotor 23 is provided between the stator 21 and the first rotor 22. The second rotor 23 is an annular structure that surrounds the periphery of the first rotor 22 and rotates around a rotation axis O. As shown in FIG. 1, the second rotor 23 is coupled to an output shaft 24 and drives a load connected to the output shaft 24. As shown in FIG. 2, the second rotor 23 has magnetic poles 231 and non-magnetic portions 232 arranged alternately in the circumferential direction. The magnetic poles 231 are made of a magnetic material (a soft magnetic material or a hard magnetic material). The non-magnetic portions 232 are made of a non-magnetic material. The non-magnetic portions 232 may be gaps formed by cutting out a magnetic material in the radial direction.

[0026] 2, a plurality of magnets 213 may be arranged in an annular shape between the stator 21 and the second rotor 23 (on the inner circumferential surface of the teeth 211 of the stator 21). In other embodiments, the magnets 213 may be omitted.

[0027] The control device 3 is a device for controlling the operation of the synchronous machine 2. The control device 3 according to this embodiment has an induced voltage angle estimating unit 31. The induced voltage angle estimating unit 31 has an interlinkage magnetic flux estimating unit 310 and a calculating unit 311.

[0028] The flux linkage estimation unit 310 estimates the angle of the magnetic flux linking to the armature winding 212 based on the angle (first angle) of the first rotor 22 and the angle (second angle) of the second rotor 23. The flux linkage estimation unit 310 according to this embodiment acquires the angle of the first rotor 22 from the first angle sensor 13 provided on the first rotor 22, and acquires the angle of the second rotor 23 from the second angle sensor 14 provided on the second rotor 23.

[0029] The calculation unit 311 calculates the electrical angle of the induced voltage of the armature based on the estimated angle of the magnetic flux. The calculated electrical angle of the induced voltage is output to the power converter 4.

[0030] The power converter 4 is electrically connected to the synchronous machine 2 via the power line 11 (the armature winding 212 of the synchronous machine 2). The power converter 4 adjusts the frequency, voltage, and current of the power that drives the synchronous machine 2 using techniques such as V / f control and vector control, based on the power frequency command value and the electrical angle of the induced voltage input from the control device 3.

[0031] (Control device operation) Next, the operation of the control device 3 according to this embodiment will be described in detail. As an example, a specific configuration will be described in which the first rotor 22 has permanent magnets arranged to completely cover the outer circumferential surface of the core 221. First, the flux linkage angle estimation performed by the flux linkage estimation unit 310 will be described. A typical synchronous machine does not have a second rotor, so the flux linkage angle is directly determined from the first rotor. Therefore, angle estimation is not necessary. Angle estimation is effective for machines with multiple rotors, such as magnetic-geared motors. For simplicity, the angle of the first rotor is defined as the reference direction in which its magnetomotive force is maximized. The magnetomotive force at a position advanced by an angle θ from the reference direction of the first rotor can be approximated by the following equation (1): where p1 is the number of poles of the first rotor. For a rotor with magnets, the mechanical angle of the rotor multiplied by the number of poles divided by 2 is called the electrical angle. During one mechanical rotation of the rotor, the magnetomotive force alternates by p1 / 2 according to the electrical angle.

[0032]

number

[0033] Let us assume that the angle of the first rotor 22 measured with respect to one armature of the stator 21 is θ1. In this case, from equation (1), the magnetomotive force in the direction θ ahead from the reference point of the stator 21 is given by the following equation (2).

[0034]

number

[0035] Since the second rotor 23 has magnetic poles 231 and non-magnetic portions 232 arranged alternately in the circumferential direction, the ease with which the magnetic flux passes through the second rotor 23, i.e., the permeance, varies depending on the angle of the second rotor 23, in other words, the circumferential position on the second rotor 23. If the angle of the second rotor is based on the circumferential direction where the permeance is maximized, the permeance at a position on the second rotor that is an angle θ ahead from the reference direction of the second rotor can be approximated by the following equation (3). Here, p2 is the number of poles of the second rotor 23. In a rotor that obtains power from changes in permeance, the value obtained by multiplying the rotor angle (mechanical angle) by the number of poles is the electrical angle. When the rotor makes one mechanical revolution, the permeance repeats a cycle of increase and decrease p2 times. Also, B 20 ≧B 21 > 0. This represents the physical constraint that permeance must always be positive.

[0036]

number

[0037] Let us assume that the angle of the second rotor 23 is measured as θ2 with one armature of the stator 21 as the reference point. In this case, the permeance in the direction θ ahead from the reference point of the stator 21 is given by the following equation (4).

[0038]

number

[0039] When the angle of the first rotor 22 is θ1 and the angle of the second rotor 23 is θ2, the magnetic flux linking the armature in a direction θ ahead from the reference point of the stator 21 is expressed by the following equation: The symbol φ(θ)|θ1,θ2 means the magnetic flux φ at angle θ based on the prior information that "the angle of the first rotor 22 is θ1 and the angle of the second rotor 23 is θ2."

[0040]

number

[0041] Generally, the angle of the magnetic flux θ φ is the angle at which the magnitude of the magnetic flux is maximum, so θ φ is expressed by the following equation (6): Equation (5) may be solved by numerical search so that the partial differential with respect to the interlinking θ becomes zero, or may be solved numerically.

[0042]

number

[0043] Here, the synchronous machine 2 of the type in which the magnet 213 is not provided between the second rotor 23 and the teeth 211 of the stator 21 has been described as an example, but the calculation can be performed in the same way for other types of synchronous machines 2 (types in which the magnet 213 is provided as shown in Figure 2).

[0044] Furthermore, here, the flux linkage estimation unit 310 calculates the magnetic flux direction from constants such as A1, B20, and B21. Alternatively, the maximum direction can be determined by numerical analysis or experiment. For example, a table for estimating the armature flux linkage from the angle of the first rotor 22 and the angle of the second rotor 23 may be prepared in advance. In this case, the flux linkage estimation unit 310 measures the angle θ1 of the first rotor 22 and the angle θ2 of the second rotor 23, and calculates the angle of the flux linkage from the prepared table.

[0045] Furthermore, the electrical angle of the induced voltage (generally the flux linkage angle advanced by π / 2 electrical angle) can be determined from the angle of the flux linkage. The calculation unit 311 calculates the electrical angle of the induced voltage based on the angle of the flux linkage estimated by the flux linkage estimation unit 310. The calculated electrical angle of the induced voltage is output to the power converter 4.

[0046] (Power converter operation) 3 is a diagram for explaining the concept of operation of the power converter according to the first embodiment of the present disclosure. In this embodiment, the output shaft is connected to the second rotor. The power converter 4 is an example of controlling the synchronous machine 2 by vector control based on the electrical angle of the induced voltage. Vector control generally adjusts the output torque of the synchronous machine 2. A command value for the output torque is output by a speed controller placed above the vector controller. The speed controller receives a power frequency command representing the speed command and the electrical angle frequency of the load shaft, and outputs a torque command by, for example, calculating proportional-integral control. In this embodiment, the second rotor 23 corresponds to the load shaft. The vector controller outputs a voltage command and a frequency command based on the electrical angle of the induced voltage and the current of the power output by the power converter 4. The power converter 4 supplies power to the armature in accordance with the voltage command and frequency command.

[0047] (Action and effect) As described above, the variable speed power unit 1 according to this embodiment includes an induced voltage angle estimation unit 31 that estimates the electrical angle of the induced voltage generated in the armature from the angle of the first rotor 22 and the angle of the second rotor 23 of the synchronous machine 2, and a power converter 4 that adjusts the frequency of the power that drives the synchronous machine 2 based on the estimated electrical angle of the induced voltage. Moreover, the induced voltage angle estimation unit 31 according to this embodiment includes a flux linkage estimation unit 310 that estimates the angle of the magnetic flux linking the armature winding 212 based on the angle of the first rotor 22 and the angle of the second rotor 23, and a calculation unit 311 that calculates the electrical angle of the induced voltage based on the angle of the flux linkage and the angle of the second rotor 23.

[0048] When vector control is used in the power converter 4, the response speed of the mechanical output of the synchronous machine 2 is improved compared to when V / f control is used. Vector control requires the electrical angle of the induced voltage. However, with conventional technology, the electrical angle of the induced voltage was unknown, making it impossible to obtain the rapid response that vector control inherently provides. Alternatively, an inaccurate electrical angle of the induced voltage could cause the first rotor to vibrate, resulting in loss of synchronization. According to this embodiment, vector control is performed using the electrical angle of the induced voltage estimated based on the angle of the first rotor and the angle of the second rotor, and the inherent quick response of vector control improves the quick response of the magnetic-geared motor or prevents loss of synchronization.

[0049] <Second embodiment> Next, a variable speed power unit 1 according to a second embodiment of the present disclosure will be described. Components common to the above-described embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0050] FIG. 4 is a diagram showing the functional configuration of a variable speed power unit according to the second embodiment of the present disclosure. 4, the control device 3 according to this embodiment further includes a first angle estimator 32. The first angle estimator 32 calculates the relationship between the angle (second angle) of the second rotor 23 measured by the second angle sensor 14 and the electrical angle θ of the voltage using adjustment constants β1 and β2 that are determined in advance, for example, through testing or analysis. V The angle of the first rotor 22 (first angle) is estimated based on the above.

[0051] (Control device operation) Next, the operation of the control device 3 according to this embodiment will be described in detail. The control device 3 according to this embodiment uses a first angle estimator 32 that estimates the angle of the first rotor 22 from the angle of the second rotor 23 and the voltage and current of the three-phase AC, instead of the first angle sensor 13 of the first rotor 22.

[0052] The measured value of the angle of the second rotor 23 is defined as θ2, and the number of revolutions of the first rotor when the second rotor 23 makes one revolution under no load is defined as n 12 Then, the angle of the first rotor 22 can be approximated from the measured value θ2 of the angle of the second rotor 23 by a transfer function expressed by the following equation (7).

[0053]

number

[0054] Transfer function parameter n 12 , J, C, and K are values ​​specific to the synchronous machine 2 and can be determined by prior testing, etc. 12The value of can be calculated from the number of poles p2 of the second rotor 23 and the number of poles p1 of the first rotor. When the magnetic poles 222 of the first rotor 22 and the magnetic poles 231 of the second rotor 23 both have permanent magnets or electromagnets, or when they both have neither permanent magnets nor electromagnets, 12 If only the magnetic pole 222 of the first rotor 22 has a permanent magnet or an electromagnet, then "n 12 If only the magnetic pole 231 of the second rotor 23 has a permanent magnet or an electromagnet, then "n 12 =p2 / (2p1)". The first angle estimator 32 calculates this transfer function. If it is found in a preliminary test that the value of a parameter K of the transfer function changes significantly depending on the output torque of the synchronous machine, the value of K etc. may be changed depending on the operation of the synchronous machine.

[0055] The operations of the flux linkage estimation unit 310 and the calculation unit 311 are the same as those in the first embodiment.

[0056] (Action and effect) As described above, the variable speed power unit 1 according to this embodiment further includes the first angle estimator 32 that estimates the angle of the first rotor 22 based on the angle of the second rotor 23.

[0057] This eliminates the need for the first angle sensor 13 that measures the angle of the first rotor 22 and the associated wiring, thereby making it possible to make the variable speed power unit 1 more compact and less expensive.

[0058] <Third embodiment> Next, a variable speed power unit 1 according to a third embodiment of the present disclosure will be described. In this embodiment, the output shaft is connected to the second rotor. Components common to the above-described embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0059] (Configuration of the first rotor) FIG. 5 is a cross-sectional view of a first rotor according to a third embodiment of the present disclosure. 5, the first rotor 22 according to this embodiment has a lightening portion 223 formed around the rotation axis O. The lightening portion 223 is formed by removing light from the core 221 of the first rotor 22.

[0060] In the second embodiment, the first angle estimator 32 estimates the angle of the first rotor 22 instead of the first angle sensor 13 of the first rotor 22. That is, an estimated value is used instead of the actual value of the angle of the first rotor 22. The estimated value of the angle of the first rotor 22 is calculated using an equation of motion consisting of the moment of inertia of the first rotor 22 and the electromagnetic torque acting on the first rotor 22. The accuracy of the estimated value of the angle of the first rotor 22 depends on the natural frequency ω n and the damping ratio ζ are higher. These can be achieved by reducing the moment of inertia of the second rotor 23.

[0061] If the moment of inertia is expressed as J [kgm2], the mechanical angle gradient of the electromagnetic torque as K [Nm / rad], and the mechanical angular velocity gradient of the electromagnetic torque as C [Nm / (rad / s)], the characteristic equation is "Js 2 +Cs+K=0". The characteristic root is "-C±√(C 2 -4KJ / 2J. The natural angular frequency ω n is "√(K / J)" and the damping ratio ζ is "C / 2√(KJ)".

[0062] If the first rotor 22 is not hollowed out, the moment of inertia J is large, so the natural angular frequency ω n is small, the damping ratio ζ is small, and the accuracy of estimating the angle of the first rotor 22 may deteriorate.

[0063] In this embodiment, the moment of inertia J of the first rotor 22 is lowered, and both the natural angular frequency and the damping ratio are increased, so that the transfer function (Equation 7) described in the second embodiment is changed to a damped first-order delay response as shown in the following Equation (8), thereby reducing the error in angle estimation in the first angle estimator 32.

[0064]

number

[0065] In order to reduce J, a lightening portion 223 is formed in the core 221 (soft magnetic material) of the first rotor 22, thereby reducing the moment of inertia of the first rotor 22.

[0066] The hollowed-out portion 223 is greater at the center of the circumferential extent of the magnetic pole 222 (the center of the magnetic pole 222) and is smaller between adjacent magnetic poles (the middle of the magnetic poles). In other words, the radial length of the hollowed-out portion 223 (the length from the rotation axis O) is set to be longer as it approaches the center of the magnetic pole 222 and shorter as it approaches the middle between two adjacent magnetic poles 222.

[0067] The first rotor 22 is not connected to an external load. When there is no load, the rotor of a synchronous machine is balanced by facing at an angle where the magnetic flux is at its maximum. At this time, as shown in Figure 5, the main component of the magnetic flux is radial at the center of the magnetic pole, and the circumferential component is small. Therefore, even if the center of the magnetic pole is deeply hollowed out, the magnetic flux is not obstructed.

[0068] The thickness of the hollowed portion 223 is large at the center of the magnetic pole 222 and small at the middle of the magnetic pole, specifically, as shown in FIG. 5, the length d of the hollowed portion is measured from the center of the magnetic pole by an angle θ m When measured against, the following equation (9) holds.

[0069]

number

[0070] Here, E(d(θ m )) is the average value of d. If there are multiple holes, calculate d for each hole and sum them up to E(d(θ m )) becomes.

[0071] (Action, effect) As described above, in the variable speed power unit 1 according to this embodiment, the first rotor 22 has the lightening portion 223 around the rotation axis O.

[0072] This reduces the moment of inertia of the first rotor 22 and increases the damping ratio, thereby improving the accuracy with which the first angle estimator 32 estimates the angle of the first rotor 22.

[0073] In this embodiment, since the angle of the first rotor 22 can be estimated with high accuracy, the processing of the flux linkage estimation unit 310 may be simplified. Specifically, the flux linkage estimation unit 310 may estimate the angle of the flux linkage by approximating the electrical angle of the first rotor 22 by a weighted sum of the electrical angle of the second rotor 23 and the electrical angle of the voltage.

[0074] The radial length of the hollowed portion 223 is set to increase as it approaches the center of the magnetic pole 222.

[0075] In this way, the hollowed portion 223 can be formed without interfering with the magnetic flux.

[0076] <Fourth embodiment> Next, a variable speed power unit 1 according to a fourth embodiment of the present disclosure will be described. In this embodiment, the output shaft is connected to the second rotor. Components common to the above-described embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0077] (Configuration of the first rotor) FIG. 6 is a cross-sectional view of a first rotor according to the fourth embodiment of the present disclosure. FIG. 7 is a perspective view of a first rotor according to the fourth embodiment of the present disclosure. As shown in FIGS. 6 and 7, the first rotor 22 according to this embodiment further has a damper winding 224 wound so as to interlink with the magnetic flux passing through the meridian plane including the center of the magnetic pole 222.

[0078] Fig. 7 is an image of a portion of the first rotor 22 cut along a meridian plane in the circumferential direction. In order to wind the damper windings 224 so that the magnetic flux penetrating the meridian plane including the center of the magnetic pole 222 interlinks, for example, the conductor may be wound on the meridian plane including the center of the magnetic pole, as shown in Fig. 7. In the example of Fig. 7, the damper windings 224 are wound around the deepest hollowed-out portion of the hollowed-out portion 223 (the inner peripheral surface of the core 221) and the outer peripheral surface of the core 221 in the radial direction.

[0079] The damping coefficient additionally generated by the damper winding 224 is C d Then, the transfer function of the first rotor 22 is expressed by the following equation (10).

[0080]

number

[0081] In addition, in this embodiment, J is reduced by removing the material as in the third embodiment, so the transfer function has a coefficient n 12 That is, first rotor 22 can follow the angle of second rotor 23 without delay, so that loss of synchronization can be more reliably suppressed.

[0082]

number

[0083] (Action, effect) As described above, in the variable speed power unit 1 according to this embodiment, the first rotor 22 further has the damper winding 224 wound so as to interlink with the magnetic flux passing through the meridian plane including the center of the magnetic pole 222.

[0084] By doing so, the variable speed power unit 1 becomes even less susceptible to step-out than the third embodiment.

[0085] <Fifth embodiment> Next, a variable speed power unit 1 according to a fifth embodiment of the present disclosure will be described. In this embodiment, the output shaft is connected to the second rotor. Components common to the above-described embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0086] (Functional configuration of variable speed power unit) FIG. 8 is a diagram showing the functional configuration of a variable speed power unit according to the fifth embodiment of the present disclosure. As shown in FIG. 8, the variable speed power unit 1 according to this embodiment further includes a first electric motor 5 in addition to the configuration according to the second embodiment. The first electric motor 5 has a rotor 51 (third rotor) and electric wires 52. The first electric motor 5 is, for example, an induction motor. The first electric motor 5 is configured so that its synchronous speed is equal to that of the synchronous machine 2 or so that its number of poles is equal to that of the synchronous machine 2.

[0087] The rotor 51 of the first electric motor 5 is mechanically connected to the first rotor 22 of the synchronous machine 2 .

[0088] The electric wire 52 is electrically connected in parallel with the armature winding 212 of the synchronous machine 2 .

[0089] (Operation of the first motor and power converter) In the third and fourth embodiments, the damping ratio of the motion of the first rotor 22 is improved by the lightening portion 223 and the damper winding 224 of the first rotor 22. However, because the first rotor 22 is inside the synchronous machine 2, there are space restrictions, and in some cases the damping ratio cannot be sufficiently improved by the lightening portion 223 and the damper winding 224 alone.

[0090] For this reason, in this embodiment, the functions of the lightening hole 223 and the damper winding 224 in the third and fourth embodiments are replaced by the externally disposed first electric motor 5. The first electric motor 5 is connected to the power converter 4 and consumes a portion of the three-phase AC power that the power converter 4 supplies to the synchronous machine 2. Due to the nature of an induction machine, the first electric motor generates a damping force proportional to the difference between the synchronous speed of the first electric motor 5, which is determined by the frequency of the power, and the rotational speed of the first electric motor 5. Because the first electric motor 5 is connected to the first rotor 22, the generated damping force also acts on the first rotor as a damping force. For this reason, the same effect as when the damping coefficient C of the first rotor is increased can be obtained.

[0091] The first rotor 22 of the synchronous machine 2 is not connected to an external load, and therefore no load is applied to it. Therefore, the first motor 5 can be small in size.

[0092] (Action and effect) As described above, the variable speed power unit 1 according to this embodiment further includes a first electric motor 5 having a rotor 51 (third rotor) that has the same number of poles as the first rotor 22 of the synchronous machine 2 and is mechanically connected to the first rotor 22, and an electric wire 52 that is electrically connected in parallel to the armature winding 212 of the synchronous machine 2.

[0093] This improves the accuracy of the first angle estimator 32. As a result, the variable speed power unit 1 can follow more rapid load changes and expand the range in which step-out can be avoided. In other words, step-out can be more firmly suppressed.

[0094] Sixth Embodiment Next, a variable speed power unit 1 according to a sixth embodiment of the present disclosure will be described. In this embodiment, the output shaft is connected to the second rotor. Components common to the above-described embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0095] (Functional configuration of variable speed power unit) FIG. 9 is a diagram showing the functional configuration of a variable speed power unit according to the sixth embodiment of the present disclosure. As shown in FIG. 9, the variable speed power unit 1 according to this embodiment further includes a reducer 6 in addition to the configuration according to the second embodiment.

[0096] The reducer 6 has a coupling 63 that connects the first rotor 22 and the second rotor 23 of the synchronous machine 2. The coupling 63 is an elastic coupling or a viscous coupling. The reducer 6 also has a first gear 61 and a second gear 62. The first gear 61 is connected to the output shaft 24 of the synchronous machine 2. Therefore, the first gear 61 rotates at the same speed as the second rotor 23. The second gear 62 further transmits the power of the second rotor 23 of the synchronous machine 2, transmitted from the first gear 61, to the coupling 63. The coupling 63 is connected to the first rotor 22 via a shaft 64. As a result, the angle of the first rotor 22 follows the angle of the second rotor 23. If the speed ratio of the reducer 6 is equal to the speed ratio of the first rotor to the second rotor, the reducer will steadily operate without load. Only when a transient speed difference occurs between the two rotors, the viscoelastic coupling acts to generate a damping force corresponding to the speed difference. This has the same effect as increasing the damping coefficient C of the first rotor 22. This makes it possible to suppress vibration of the first rotor 22 relative to the second rotor 23. This makes it possible to improve the accuracy with which the first angle estimator 32 estimates the angle of the first rotor 22.

[0097] 9 shows an example in which the components of the reducer 6 (the first gear 61, the second gear 62, the joint 63, and the shaft 64 connecting the joint 63 and the first rotor 22) are arranged outside the synchronous machine 2, but this is not limitative. In other embodiments, the reducer 6 may be configured, for example, by a planetary gear and arranged inside the synchronous machine 2.

[0098] (Action and effect) As described above, the variable speed power unit 1 according to this embodiment further includes a reducer 6 connected to the synchronous machine. The reducer 6 has a joint 63 that connects the first rotor 22 and the second rotor of the synchronous machine 2.

[0099] In this way, variable speed power unit 1 can suppress irregular vibration of first rotor 22 of synchronous machine 2 relative to second rotor 23. This improves the accuracy with which first angle estimator 32 estimates the angle of first rotor 22.

[0100] Seventh Embodiment Next, a variable speed power unit 1 according to a seventh embodiment of the present disclosure will be described. In this embodiment, the output shaft is connected to the second rotor. Components common to the above-described embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0101] (Functional configuration of variable speed power unit) FIG. 10 is a diagram showing the functional configuration of a variable speed power unit according to the seventh embodiment of the present disclosure. As shown in FIG. 10, the variable speed power unit 1 according to this embodiment further includes a second electric motor 7 and a second power converter 8 in addition to the configuration according to the second embodiment.

[0102] The second motor 7 has a rotor 71 (fourth rotor). The rotor 71 is mechanically connected to the first rotor 22 of the synchronous machine 2. Similar to the first motor 5 of the fifth embodiment, the second motor 7 is, for example, a small induction motor or a small synchronous motor.

[0103] The second power converter 8 adjusts the frequency of the power that drives the second electric motor 7, thereby supplying electric power to the second electric motor 7 so that the rotation speed of the second rotor 23 matches the rotation speed of the first rotor of the synchronous machine 2. Furthermore, the second power converter 8 may supply electric power to the second electric motor 7 so as to assist the synchronous machine 2.

[0104] (Operation of the second motor and the second power converter) As shown in Fig. 10, a second electric motor 7 is connected to the first rotor 22 of the synchronous machine 2. The second electric motor 7 is supplied with power from a second power converter 8. The second power converter 8 converts p1n into the rotation speed [rps] of the second rotor 23 obtained from the time differential value of the angle of the second rotor 23 of the synchronous machine 2.12 / 2 to generate a target frequency for the second power converter 8 so that the rotation speed of the second rotor 23 becomes the synchronous rotation speed of the first rotor 22. The second power converter 8 adjusts the frequency and phase of the power that drives the second electric motor 7 so that the rotation speed of the first rotor 22 matches the synchronous rotation speed. Furthermore, the second power converter 8 may additionally advance the phase of the voltage of the power that drives the second electric motor 7 so as to assist the synchronous machine 2.

[0105] (Action and effect) As described above, the variable speed power unit 1 according to this embodiment further includes the second electric motor 7 mechanically connected to the first rotor 22 of the synchronous machine 2, and the second power converter 8 that adjusts the frequency of the electric power that drives the second electric motor 7 so that it matches the speed of the second rotor 23 of the synchronous machine 2. The electric power supplied to the second electric motor 7 by the second power converter 8 acts as a damping force when the second electric motor 7 and the first rotor 22 move relative to the second rotor 23, thereby limiting this relative movement. Furthermore, when the synchronous machine 2 is powered by the second power converter 8 and the second electric motor 7, the load driving capacity is improved.

[0106] In this way, the variable speed power unit 1 can suppress irregular vibration of the first rotor 22 of the synchronous machine 2 relative to the second rotor 23. This improves the accuracy with which the first angle estimator 32 estimates the angle of the first rotor 22. As a result, the variable speed power unit 1 can follow more rapid load changes and expand the range in which loss of synchronism can be avoided. In other words, loss of synchronism can be suppressed even more firmly.

[0107] Eighth Embodiment Next, a variable speed power unit 1 according to an eighth embodiment of the present disclosure will be described. Components common to the above-described embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0108] (Functional configuration of variable speed power unit) FIG. 11 is a diagram showing the functional configuration of a variable speed power unit according to an eighth embodiment of the present disclosure. As shown in FIG. 11 , the variable speed power unit 1 according to this embodiment does not include a flux linkage estimation unit 310. The flux linkage estimation unit 310 performs vector control in the power converter 4 based on the electrical angle of the induced voltage between the first rotor 22 and the second rotor 23. In this embodiment, the power converter 4 uses V / f control instead of vector control, thereby eliminating the need to estimate the electrical angle of the induced voltage. It is known that the rotational speed of a synchronous machine follows the synchronous speed of the frequency of the drive power with a time delay and ultimately settles at the synchronous speed. The magnetic-geared motor of this application also belongs to the synchronous machine category and therefore has this property.

[0109] Therefore, if the change in the frequency of the drive power is not sudden, the rotation of the magnetic-geared motor will follow the synchronous speed determined by the frequency of the drive power, albeit with a delay, so speed adjustment can be achieved relatively easily by adjusting the frequency of the drive power. However, if the frequency of the drive power is changed suddenly, the delay in rotation will be excessive, causing loss of synchronization and the original function of the synchronous machine will be lost.

[0110] Since a magnetic-geared motor has a first rotor and a second rotor, each rotor is susceptible to loss of synchronization. Loss of synchronization occurs when the offset between the electrical angle of the drive power voltage and the rotor electrical angle exceeds ±90°. Therefore, the offsets of the two rotors are compared, and the drive power voltage of the rotor with the larger offset is adjusted so that the offset does not exceed ±90° to prevent loss of synchronization. The angle of the first rotor 22 is measured by the first angle sensor 13. The induced voltage angle estimator 31 obtains the electrical angle of the first rotor by dividing the value measured by the first angle sensor 13 by half the number of poles p1 of the first rotor. Similarly, the induced voltage angle estimator 31 obtains the electrical angle of the second rotor by dividing the value measured by the second angle sensor 14 by the number of poles p2 of the second rotor.

[0111] This will be explained in detail with reference to Fig. 12. The power converter 4 receives the electrical angle of the induced voltage of the first rotor 22 and the electrical angle of the induced voltage of the second rotor 23, and calculates offset 1 and offset 2 for the respective voltage electrical angles. Offset 1 and offset 2 are compared, and the value with the larger absolute value is determined as the final offset. Based on the final offset, the electrical angle θ of the voltage of the power that drives the synchronous machine 2 is calculated. V to avoid step-out of the synchronous machine 2. For example, as shown in FIG. 12, this adjustment is performed by load adjuster 411 of calculation function unit 41 inside power converter 4, so that if the final offset is within a predetermined allowable range (for example, a range of [-30°, +30°]), the adjustment value of the frequency command is zero. If the final offset exceeds the allowable range, an adjustment value proportional to the final offset is added to the frequency command so that the absolute value of the final offset becomes smaller.

[0112] The power voltage command is determined, for example, from a preset setting function based on the power frequency command.

[0113] (Action and effect) As described above, in the variable speed power unit 1 according to this embodiment, the power converter 4 performs V / f control based on the electrical angle of the first rotor 22 or the electrical angle of the second rotor 23, whichever has the larger absolute value of the offset from the electrical angle of the voltage, and adjusts the frequency of the power that drives the synchronous machine 2.

[0114] Unlike the vector control described in the first embodiment, the variable speed power unit 1 according to this embodiment does not require estimation of the angle of the resultant magnetic flux from the first rotor and the second rotor, thereby eliminating the need for processing by the flux linkage estimation unit 310. In applications requiring a gradual response, employing the variable speed power unit 1 according to this embodiment makes it possible to suppress step-out with simpler processing. A feature of this embodiment is that the drive power, particularly the frequency, is adjusted based on the electrical angle of the induced voltage of the rotor closest to step-out, either the first rotor 22 or the second rotor 23. Note that another embodiment may have a vector controller based on the electrical angle of the induced voltage of the first rotor 22 and a vector controller based on the electrical angle of the induced voltage of the second rotor 23, and vector control may be performed using the vector controller of the rotor closest to step-out.

[0115] <Ninth embodiment> Next, a variable speed power unit 1 according to a ninth embodiment of the present disclosure will be described. Components common to the above-described embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0116] FIG. 13 is a diagram showing the functional configuration of a variable speed power unit according to the ninth embodiment of the present disclosure. As shown in FIG. 13, the control device 3 according to this embodiment includes an induced voltage vector estimation unit 312.

[0117] The induced voltage vector estimation unit 312 estimates the angle of the induced voltage vector based on the voltage and current of the power line 11 that drives the synchronous machine 2, and outputs the electrical angle of the induced voltage. The calculated electrical angle of the induced voltage is output to the power converter 4.

[0118] FIG. 14 is a diagram illustrating a functional configuration of a power converter according to the ninth embodiment. 14, the power converter 4 according to this embodiment has a load adjuster 411 in addition to a vector controller in the calculation function unit 41. The specific configuration of the load adjuster 411 is the same as that of the eighth embodiment.

[0119] The calculation function unit 41 calculates the voltage electrical angle θ in the load regulator 411. V The frequency of the power is adjusted based on the offset of the angle (second angle) measured by the second angle sensor 14 provided on the load shaft (in this embodiment, the second rotor 23), thereby preventing the load shaft from losing synchronization.

[0120] (Control device operation) Next, the operation of the control device 3 according to this embodiment will be described in detail. The induced voltage vector estimation unit 312 estimates the induced voltage vector generated in the armature from the voltage vector, the current vector, and the impedance of the armature. The current vector and the voltage vector are calculated based on the electrical angle θ of the second rotor. e Then, they are calculated using equations (12) and (13), respectively.

[0121]

number

[0122]

number

[0123] Here, i is the phase current of the AC supplied to the synchronous machine 2, and v is the phase voltage of the AC supplied to the synchronous machine 2. The symbol "·" indicates a complex number, and j is the imaginary unit.

[0124] The synchronous machine 2 is generally driven by three-phase AC. When there is a difference between the three phases, the voltage vector and current vector are calculated using equations (14) and (15), respectively. The three phases are U, V, and W, and the electrical angles of the V and W phases are calculated by subtracting 120° (2π / 3) and 240° (4π / 3), respectively, from the electrical angle of the U phase at the same time. This embodiment also takes into account such differences between phases.

[0125]

number

[0126]

number

[0127] Alternatively, it may be simply calculated from the instantaneous value using the following equations (16) and (17).

[0128]

number

[0129]

number

[0130] If the armature impedance is represented by Z^· (Z with a "·" added above it; the same applies below), the induced voltage vector E^· can be calculated from the voltage vector V^· and the current vector I^· using the following equation (18).

[0131]

number

[0132] Here, the impedance is calculated from the resistance R and inductance L using the following equation (19). The values ​​of R and L are determined in advance. ω e is, for example, the angular frequency of the adjusted frequency command. e As the frequency, the electrical angular frequency of the first rotor 22, the electrical angular frequency of the second rotor 23, and the electrical angular frequency of the induced voltage may be used.

[0133]

number

[0134] FIG. 15 is a diagram showing an example of induced voltage vectors according to the eighth embodiment of the present disclosure, and represents a load operating state. Figure 15 shows how the angle of the induced voltage vector is offset from the electrical angle of the second rotor 23 due to the influence of the first rotor 22. In Figure 15, the electrical angle of the induced voltage vector E^·, which is the sum of the induced voltage vector E1^· of the first rotor 22 and the induced voltage vector E2^· of the second rotor 23, is plotted on the real axis. δ is the angle between the voltage vector V^· and the induced voltage vector E^·, a value called the load angle. ε is the angle between the induced voltage E^· and the induced voltage of the second rotor 23.

[0135] In a loaded operating state, the angle of the induced voltage E^ of a magnetic-geared motor is generally not determined solely by the angle of the first rotor or solely by the angle of the second rotor. To perform vector control, the angle of the induced voltage is required. In the first embodiment of the present application, the angle of the first rotor and the angle of the second rotor are measured to estimate the electrical angle of the induced voltage E^. In contrast, the first embodiment required rotor angle measurement. In contrast, this embodiment calculates the electrical angle of the induced voltage E^ based on equation (18) from the measured values ​​of the voltage vector V^ and the current vector I^. This embodiment is characterized by not requiring an angle sensor.

[0136] As described in the eighth embodiment, if the offset δ+ε of the load shaft (e.g., the second rotor) relative to the voltage vector V exceeds the range of ±90° (±π / 2), the load shaft will lose synchronization. Vector control adjusts the power supplied to the magnetic-geared motor, but it cannot dynamically adjust the power distribution to the first rotor or the second rotor. Therefore, as shown in FIG. 14, the power converter 4 includes the load adjuster 411 described in the eighth embodiment and adjusts the frequency command so that the load shaft offset δ+ε falls within a predetermined tolerance range, such as ±45°.

[0137] The load regulator 411 receives a frequency command and outputs the adjusted frequency command. The speed controller outputs a torque command, for example, by proportional-integral control, so that the electrical angular frequency of the load shaft matches the adjusted frequency command. The torque command here refers to the torque of a virtual rotating shaft that rotates at the angular frequency of the induced voltage. The vector controller adjusts the frequency command and voltage command based on the electrical angle of the induced voltage, allowing the magnetic-geared motor to settle quickly. In the settling state, all of the power supplied by the power converter 4 is consumed by the load shaft, except for losses.

[0138] (Action and effect) As described above, in the variable speed power unit 1 according to this embodiment, the induced voltage vector estimation unit 312 estimates the induced voltage vector based on the voltage and current that drive the synchronous machine 2, and outputs the electrical angle of the induced voltage.

[0139] This allows vector control to be performed in the variable speed power plant 1 even without a rotor angle meter.

[0140] <Tenth embodiment> Next, a variable speed power unit 1 according to a tenth embodiment of the present disclosure will be described. Components common to the above-described embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0141] FIG. 16 is a diagram showing the functional configuration of a variable speed power unit according to a tenth embodiment of the present disclosure. 16, the induced voltage vector estimator 312 according to this embodiment estimates the load angle δ based on the voltage, current, and electrical angle frequency of the voltage of the power that drives the synchronous machine 2. In this embodiment, the second angle sensor 14 of the second rotor 23 is not required.

[0142] (Operation of the control device and power converter) In the ninth embodiment, a second angle sensor 14 is required to measure the angle of the second rotor 23, which requires costs for the sensor and wiring. On the other hand, this embodiment does not require the costs for the sensor and wiring to measure the angle. Specifically, in this embodiment, the current vector and the induced voltage vector are calculated based on the voltage vector.

[0143] FIG. 17 is a diagram for explaining an example of the operation of the power converter according to the tenth embodiment of the present disclosure. The power converter 4 outputs a voltage that matches the voltage electrical angle command inside the power converter 4. Therefore, the voltage electrical angle is determined by the voltage electrical angle command θ V The voltage amplitude follows the command value |V| inside the power converter 4, and the real axis is v Then, the voltage vector is expressed by the following equation (21).

[0144]

number

[0145] Electrical angle θ of voltage vector V Based on this, the current vector is expressed as in the following equation (22).

[0146]

number

[0147] FIG. 18 is a diagram showing an example of a load angle according to the tenth embodiment of the present disclosure. The induced voltage vector E^ can be calculated from the voltage vector V^ and the current vector I^ using the above equation (18), as in the eighth embodiment. The impedance in equation (19) is calculated using the electrical angular frequency ω eIn this embodiment, since the voltage vector is used as a reference, the electrical angle of the induced voltage vector is the load angle δ, as shown in Fig. 18. Therefore, as shown in Fig. 17, the power converter 4 does not calculate the load angle δ in the calculation function unit 41, but calculates a correction value for the frequency command value using the electrical angle (load angle δ) of the induced voltage vector input from the control device 3.

[0148] (Action and effect) As described above, in the variable speed power unit 1 according to this embodiment, the induced voltage vector estimating unit 312 estimates the load angle δ based on the voltage, current, and electrical angle frequency of the voltage of the power that drives the synchronous machine 2.

[0149] In this way, the variable speed power unit 1 does not need to measure the first angle of the first rotor 22. This makes it possible to reduce the costs of the first angle sensor 13 and wiring.

[0150] <Eleventh embodiment> Next, a variable speed power unit 1 according to an eleventh embodiment of the present disclosure will be described. Components common to the above-described embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0151] FIG. 19 is a diagram showing the functional configuration of a variable speed power unit according to an eleventh embodiment of the present disclosure. As shown in Fig. 19, the control device 3 according to this embodiment further includes an impedance change unit 33. Note that Fig. 19 illustrates an example in which the impedance change unit 33 is added to the configuration of the tenth embodiment (Fig. 16), but the present invention is not limited to this. In other embodiments, the impedance change unit 33 may be added to the configuration of the ninth embodiment (Fig. 13).

[0152] The impedance change unit 33 calculates the active power, reactive power, and voltage electrical angular frequency ω eThe impedance value of the armature is changed based on the above. The electrical angular frequency is not limited to the voltage. For example, the electrical angular frequencies of the current, the first rotor, and the second rotor match the electrical angular frequency of the voltage in the settled state. These electrical angular frequencies may be used instead of the electrical angular frequency of the voltage.

[0153] Furthermore, the induced voltage vector estimating unit 312 according to this embodiment estimates the induced voltage vector based on the current that drives the synchronous machine 2, the electrical angle of the voltage, and the changed impedance value.

[0154] (Control device operation) The impedance of the armature is used to estimate the induced voltage vector. This impedance is not a constant value, but varies depending on the motion of the first rotor 22 and the second rotor 23 and the ease with which magnetic flux passes (permeance) in the magnetic circuit inside the synchronous machine 2 due to magnetic saturation. In this embodiment, the value of the impedance is changed depending on the active power, reactive power, and rotation speed of the synchronous machine 2.

[0155] The initial value of the impedance is set by a prior test, etc. The electrical angular frequency of the voltage V may be substituted by the electrical angular frequency of the second rotor.

[0156] The active power P is the power that drives the load, and is calculated from the voltage vector V^· and the current vector I^· using the following equation (23).

[0157]

number

[0158] Here, the symbol * represents the conjugate complex number, and Re represents the real part of the complex number.

[0159] The reactive power Q is not used to drive the load but is mainly stored as magnetic energy, and is calculated using the following equation (24).

[0160]

number

[0161] In equation (24), Im represents the imaginary part of a complex number.

[0162] (Action and effect) As described above, the variable speed power unit 1 according to this embodiment further includes an impedance change unit 33 that changes the value of the impedance based on the active power, reactive power, and electrical angle frequency of the voltage of the synchronous machine 2. Furthermore, the induced voltage vector estimation unit 312 estimates the induced voltage vector based on the current that drives the synchronous machine 2, the electrical angle of the voltage, and the changed value of the impedance.

[0163] By doing so, the variable speed power unit 1 can reflect the change in impedance in the calculation of the induced voltage vector, and can therefore estimate the induced voltage vector with higher accuracy.

[0164] <Twelfth embodiment> Next, a variable speed power unit 1 according to a twelfth embodiment of the present disclosure will be described. Components common to the above-described embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0165] FIG. 20 is a diagram showing the functional configuration of a variable speed power unit according to a twelfth embodiment of the present disclosure. The control device 3 according to this embodiment is an improvement of the control device 3 according to the ninth embodiment. Specifically, as shown in Fig. 20, the control device 3 according to this embodiment further includes a phase compensation unit 314 in addition to an induced voltage vector estimation unit 312.

[0166] The phase compensation unit 314 (phase compensator) generates a phase compensation signal for phase compensation for the inertia of the first rotor 22 based on the electrical angle of the second rotor 23.

[0167] Furthermore, the induced voltage vector estimation unit 312 according to this embodiment calculates the electrical angle θ of the first rotor 22 in addition to the electrical angle of the induced voltage based on the voltage, current, and electrical angular frequency of the voltage of the power that drives the synchronous machine 2.e1 Estimate.

[0168] (Control device operation) The magnetic-geared motor has a first rotor 22 and a second rotor 23. The armature is common to the two rotors. For this reason, even if power is applied to the second rotor 23 from the armature, part of the power excites the motion of the first rotor 22, causing the first rotor 22 to vibrate. The aim of this embodiment is to apply a damping force to the first rotor 22 to suppress the vibration of the first rotor 22.

[0169] The induced voltage vector E1^ of the first rotor 22 coincides with the voltage vector V^ in the steady state. However, in the transient state, the first rotor 22 also uses power to accelerate or decelerate its own inertia, so the two do not coincide. Therefore, the induced voltage vector E1^ of the first rotor 22 is estimated from equation (25).

[0170]

number

[0171] The induced voltage vector E2^· of the second rotor 23 has a magnitude A E2 The angle θ of the voltage vector is assumed to be obtained through a test in advance. V , the angle of the current vector θ I , the electrical angle θ of the second rotor 23 e2 Using the measured values, the induced voltage vector of the first rotor 22 can be expressed by equation (26).

[0172]

number

[0173] Therefore, the angle of the induced voltage vector, i.e., the electrical angle θ of the first rotor 22 e1 is obtained by equation (27).

[0174]

number

[0175] The phase compensation unit 314 adjusts the electrical angle θ of the first rotor 22. e1 Based on this, the compensation torque is calculated and output. Compensation torque T D is generated in proportion to the speed of the first rotor 22, for example, as in equation (28), where kD and τD are adjustment constants, and s is the Laplace operator.

[0176]

number

[0177] (Power converter operation) FIG. 21 is a diagram illustrating a functional configuration of a power converter according to a twelfth embodiment of the present disclosure. As shown in Fig. 21, the power converter 4 inputs the compensation torque, and the calculation function unit 41 subtracts the torque compensation signal from the torque command output by the speed controller to calculate the compensated torque command. The vector controller adjusts the power frequency and voltage according to the compensated torque command.

[0178] (Action and effect) As described above, in the variable speed power unit 1 according to this embodiment, the induced voltage angle estimator 31 derives the electrical angle θ of the first rotor 22 in addition to the electrical angle of the induced voltage based on the voltage, current, and electrical angle frequency of the voltage of the power that drives the synchronous machine 2. e1 Estimate.

[0179] In this way, the variable speed power unit 1 can damp vibrations of the first rotor 22 while suppressing loss of synchronism of the synchronous machine 2.

[0180] <Hardware configuration> FIG. 22 is a diagram illustrating an example of a hardware configuration of devices that constitute a variable speed power unit according to at least one embodiment of the present disclosure. An example of the hardware configuration of the control device 3, power converter 4, and second power converter 8 that constitute the variable speed power unit 1 will be described below with reference to FIG.

[0181] As shown in FIG. 22, a computer 1000 includes a processor 1001, a main memory device 1002, an auxiliary memory device 1003, and an interface 1004.

[0182] The control device 3, the power converter 4, and the second power converter 8 described in each of the above-described embodiments are each implemented in a computer 1000. The operations of each of the above-described processing units are stored in the auxiliary storage device 1003 in the form of a program. The processor 1001 reads the program from the auxiliary storage device 1003, loads it into the main storage device 1002, and executes the above-described processing in accordance with the program. The processor 1001 also allocates storage areas in the main storage device 1002 to be used for various processes in accordance with the program. The processor 1001 also allocates storage areas in the auxiliary storage device 1003 to store data being processed in accordance with the program.

[0183] The program may be for realizing some of the functions to be performed by the computer 1000. For example, the program may be combined with other programs already stored in the auxiliary storage device 1003 or other programs implemented in other devices to perform the functions. In other embodiments, the computer 1000 may include a custom LSI (Large Scale Integrated Circuit) such as a PLD (Programmable Logic Device) in addition to or instead of the above configuration. Examples of PLDs include PAL (Programmable Array Logic), GAL (Generic Array Logic), CPLD (Complex Programmable Logic Device), and FPGA (Field Programmable Gate Array). In this case, some or all of the functions realized by the processor 1001 may be realized by the integrated circuit.

[0184] Examples of the auxiliary storage device 1003 include a hard disk drive (HDD), a solid state drive (SSD), a magnetic disk, a magneto-optical disk, a compact disc read-only memory (CD-ROM), a digital versatile disc read-only memory (DVD-ROM), and a semiconductor memory. The auxiliary storage device 1003 may be an internal medium directly connected to the bus of the computer 1000, or an external storage device 1010 connected to the computer 1000 via the interface 1004 or a communication line. In addition, when this program is distributed to the computer 1000 via a communication line, the computer 1000 that receives the program may load the program into the main storage device 1002 and execute the above-mentioned processing. In at least one embodiment, the auxiliary storage device 1003 and the external storage device 1010 are non-transitory tangible storage media.

[0185] As described above, several embodiments of the present invention have been described, but all of these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope of the invention and its equivalents as defined in the claims, as well as in the scope and spirit of the invention.

[0186] <Additional Notes> The variable speed power unit and the control method described in the above embodiment can be understood, for example, as follows.

[0187] (1) According to a first aspect of the present disclosure, a variable speed power device (1) includes a synchronous machine (2) having a stator (21) provided with an armature winding (212) to form an armature, a first rotor (22) having magnetic poles (222), and a second rotor (23) provided between the first rotor (22) and the stator (21) to drive a load; an induced voltage angle estimation unit (31) that estimates the electrical angle of an induced voltage generated in the armature based on a first angle of the first rotor (22) and a second angle of the second rotor (23); and a power converter (4) that adjusts the frequency of power that drives the synchronous machine (2) based on the estimated electrical angle of the induced voltage.

[0188] (2) According to a second aspect of the present disclosure, in the variable speed power unit (1) according to the first aspect, the induced voltage angle estimation unit (31) includes a flux linkage estimation unit (310) that estimates an angle of flux linkage that links with the armature winding (212) based on the first angle and the second angle, and a calculation unit (311) that estimates an electrical angle of the induced voltage based on the angle of the flux linkage.

[0189] (3) According to a third aspect of the present disclosure, in the variable speed power unit (1) according to the second aspect, the flux linkage estimation unit (310) estimates the angle of the flux linkage based on a first angle measured by a first angle sensor (13) provided on the first rotor (22) and a second angle measured by a second angle sensor (14) provided on the second rotor (23).

[0190] (4) According to a fourth aspect of the present disclosure, the variable speed power unit (1) according to the second aspect further includes a first angle estimator (32) that estimates a first angle based on a second angle measured by a second angle sensor (14) provided on the second rotor (23) and an electrical angle of a voltage that drives the synchronous machine (2).

[0191] (5) According to a fifth aspect of the present disclosure, in the variable speed power unit (1) according to the fourth aspect, the first rotor (22) has a lightening portion (223) formed around the rotation shaft.

[0192] (6) According to a sixth aspect of the present disclosure, in the variable speed power unit (1) according to the fifth aspect, the radial length of the hollowed portion (223) of the first rotor (22) is set to increase as it approaches the center of the magnetic pole (222) of the first rotor (22).

[0193] (7) According to a seventh aspect of the present disclosure, in the variable speed power unit (1) according to the fifth or sixth aspect, the first rotor (22) further has a damper winding (224) wound so as to interlink with the magnetic flux passing through a meridian plane including the center of the magnetic pole (222).

[0194] (8) According to an eighth aspect of the present disclosure, the variable speed power unit (1) according to the fourth aspect further includes a first electric motor (5) having a third rotor (51) mechanically connected to the first rotor (22) of the synchronous machine (2) and an electric wire (52) electrically connected in parallel with the armature winding (212) of the synchronous machine (2), and having the same synchronous speed as the synchronous machine (2) or the same number of poles as the synchronous machine (2).

[0195] (9) According to a ninth aspect of the present disclosure, the variable speed power unit (1) according to the fourth aspect further includes a reducer (6) connected to the synchronous machine (2), and the reducer (6) has a coupling (63) connecting the first rotor (22) and the second rotor (23) of the synchronous machine (2).

[0196] (10) According to a tenth aspect of the present disclosure, the variable speed power device (1) according to the fourth aspect further includes a second electric motor (7) connected to the first rotor (22) of the synchronous machine (2), and a second power converter (8) that adjusts the frequency of the electric power that drives the second electric motor (7) based on a second angle of the second rotor (23) of the synchronous machine (2).

[0197] (11) According to an eleventh aspect of the present disclosure, a variable speed power device (1) includes a synchronous machine (2) having a stator (21) provided with an armature winding (212) to form an armature, a first rotor (22) having magnetic poles (222), and a second rotor (23) provided between the first rotor (22) and the stator (219), and a power converter (4) that performs V / f control based on the electrical angle of the first rotor (22) or the electrical angle of the second rotor (23), whichever has a larger absolute value of offset from the electrical angle of the voltage that drives the synchronous machine (2), and adjusts the frequency of the power that drives the synchronous machine (2).

[0198] (12) According to a twelfth aspect of the present disclosure, a method for controlling a synchronous machine (2) having a stator (21) provided with an armature winding (212) to form an armature, a first rotor (22) having magnetic poles (222), and a second rotor (23) provided between the first rotor (22) and the stator (21) to drive a load includes the steps of: estimating an electrical angle of an induced voltage generated in the armature based on a first angle of the first rotor (22) and a second angle of the second rotor (23); and adjusting a frequency of power that drives the synchronous machine (2) based on the estimated electrical angle of the induced voltage. [Industrial Applicability]

[0199] According to the variable speed power unit and control method of the present disclosure, it is possible to suppress step-out of a synchronous machine. [Explanation of symbols]

[0200] 1 Variable Speed ​​Power Unit 11 Power Lines 13 First angle sensor 14 Second angle sensor 2. Synchronous Machine 21 Stator 211 teeth 212 Armature Winding 213 Magnet 22 First rotor 221 cores 222 magnetic pole 223 Hollowed-out section 224 Damper Winding 23 Second rotor 231 magnetic pole 232 Non-magnetic part 24 output shaft 3. Control device 31 Back electromotive force angle estimation unit 310 Flux linkage estimation section 311 Calculation Unit 312 Back electromotive force vector estimation unit 314 Phase compensation section 315 Load angle estimation section 32 First angle estimator 33 Impedance change unit 4 Power Converter 41 Calculation function unit 5 1st electric motor 51 Rotor (third rotor) 52 Electrical Wires 6 Reducer 61 First Gear 62 2nd Gear 63 Joint 64 axes 7 Second electric motor 71 Rotor (4th rotor) 8 Second power converter 1000 computers 1001 processor 1002 Main storage 1003 Auxiliary storage device 1004 Interface 1010 External storage device

Claims

1. a synchronous machine including a stator having an armature winding formed thereon to form an armature, a first rotor having magnetic poles, and a second rotor provided between the first rotor and the stator to drive a load; an induced voltage angle estimator that estimates an electrical angle of an induced voltage generated in the armature based on a first angle of the first rotor and a second angle of the second rotor; a power converter that adjusts a frequency of power that drives the synchronous machine based on the estimated electrical angle of the induced voltage; A variable speed power unit comprising:

2. The induced voltage angle estimation unit is a flux linkage estimator that estimates an angle of a flux linkage that links with the armature winding based on the first angle and the second angle; a calculation unit that calculates an electrical angle of the induced voltage based on the angle of the magnetic flux linkage; 2. The variable speed power system of claim 1, comprising:

3. the flux linkage estimation unit estimates an angle of the flux linkage based on the first angle measured by a first angle sensor provided on the first rotor and the second angle measured by a second angle sensor provided on the second rotor; 3. The variable speed power unit of claim 2.

4. a first angle estimator that estimates the first angle based on the second angle measured by a second angle sensor provided on the second rotor and an electrical angle of a voltage that drives the synchronous machine; 3. The variable speed power unit of claim 2.

5. The first rotor has a hollowed-out portion formed around a rotation shaft.

5. The variable speed power unit of claim 4.

6. A radial length of the hollowed portion of the first rotor is set to be longer as it approaches a center of the magnetic pole of the first rotor.

6. The variable speed power unit of claim 5.

7. The first rotor further has a damper winding wound so as to interlink with a magnetic flux passing through a meridian plane including the center of the magnetic pole.

7. A variable speed power unit according to claim 5 or 6.

8. a first motor having a third rotor mechanically connected to the first rotor of the synchronous machine and an electric line electrically connected in parallel to the armature winding of the synchronous machine, the first motor having the same synchronous speed as the synchronous machine or the same number of poles as the synchronous machine; 5. The variable speed power unit of claim 4.

9. Further comprising a reducer connected to the synchronous machine, The reducer has a joint that connects the first rotor and the second rotor of the synchronous machine.

5. The variable speed power unit of claim 4.

10. a second motor connected to the first rotor of the synchronous machine; a second power converter that adjusts a frequency of power that drives the second motor based on the second angle of the second rotor of the synchronous machine; The variable speed power plant of claim 4 further comprising:

11. a synchronous machine including a stator having an armature winding formed thereon to form an armature, a first rotor having magnetic poles, and a second rotor provided between the first rotor and the stator; a power converter that performs V / f control based on one of the electrical angle of the first rotor and the electrical angle of the second rotor, which has a larger absolute value of an offset from an electrical angle of a voltage that drives the synchronous machine, and adjusts a frequency of power that drives the synchronous machine; A variable speed power unit comprising:

12. A control method for a synchronous machine having a stator provided with an armature winding to form an armature, a first rotor having magnetic poles, and a second rotor provided between the first rotor and the stator to drive a load, comprising the steps of: estimating an electrical angle of an induced voltage generated in the armature based on a first angle of the first rotor and a second angle of the second rotor; adjusting a frequency of electric power that drives the synchronous machine based on the estimated electrical angle of the induced voltage; The control method includes:

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