Synchronous reluctance motor abnormality detection device and abnormality detection method

Abstract

An abnormality detection device (50) is adopted for a sensorless control apparatus (100) that controls operation of a voltage applicator (3) on the basis of a detection value of a motor current flowing through a synchronous reluctance motor (1) and an estimation value of a rotor position of the synchronous reluctance motor (1) estimated on the basis of the motor current. The abnormality detection device (50) is provided with a calculation unit (51) and a determination unit (52). The calculation unit (51) calculates, on the basis of the detection value of the motor current and a gate signal for use in outputting a drive voltage by the voltage applicator (3), classification information obtained by classifying a motor current change amount, which is the change amount of the motor current, by means of a reference phase of an AC component of the motor current change amount and a DC component of the motor current change amount. The determination unit (52) determines an abnormality of a rotor (1b) on the basis of the classification information calculated by the calculation unit (51).

Description

[Technical field]

[0001] The present disclosure relates to an abnormality detection device and an abnormality detection method for a synchronous reluctance motor that utilizes rotor saliency. [Background technology]

[0002] The mainstream of synchronous motors in recent years are interior permanent magnet synchronous motors and synchronous reluctance motors. Interior permanent magnet synchronous motors use magnet torque and reluctance torque in combination, while synchronous reluctance motors use only reluctance torque. Since reluctance torque is proportional to the salient pole ratio, motors that use reluctance torque require a rotor structure that ensures a salient pole ratio.

[0003] In the case of a synchronous reluctance motor, in order to secure sufficient centrifugal force strength while securing the salient pole ratio, the rotor is provided with a magnetic path through which magnetic flux passes, an air slit that constitutes a magnetic barrier, and a strength member that supports the air slit. That is, in a synchronous reluctance motor, there is a trade-off between the salient pole ratio and the centrifugal force strength. For this reason, a synchronous reluctance motor is designed to maximize the salient pole ratio while securing sufficient centrifugal force strength. However, this design does not assume that failures due to aging or unexpected failures are covered. For this reason, in a synchronous reluctance motor, in order to further improve safety, it is desirable to monitor the rotor condition and detect rotor abnormalities at an early stage.

[0004] The following Patent Document 1 discloses a technology for detecting the presence or absence of an abnormality in a rotor based on components extracted by subtracting two waveforms that have the same phase from each other in the current flowing through an AC motor. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 4062939 Summary of the Invention [Problem to be solved by the invention]

[0006] However, when using the technology of Patent Document 1, in order to subtract two current waveforms of the same phase, the AC motor needs to rotate at a constant speed. Therefore, with the technology of Patent Document 1, it is difficult to detect an abnormality in the rotor when the AC motor is started. In addition, even when not started, the rotation speed fluctuates slightly due to pulsation of the load. For this reason, the technology of Patent Document 1 may not be able to obtain sufficient detection accuracy.

[0007] The present disclosure has been made in consideration of the above, and has an object to provide an abnormality detection device for a synchronous reluctance motor that can detect an abnormality in a rotor even if the synchronous reluctance motor is not rotating at a constant speed. [Means for solving the problem]

[0008] In order to solve the above-mentioned problems and achieve the object, an abnormality detection device for a synchronous reluctance motor according to the present disclosure is applied to a sensorless control device that includes a voltage applicator that applies a drive voltage to a synchronous reluctance motor, and controls the operation of the voltage applicator based on a detected value of a motor current flowing through the synchronous reluctance motor and an estimated value of a rotor position of the synchronous reluctance motor estimated based on the motor current. The abnormality detection device for a synchronous reluctance motor includes a calculation unit and a judgment unit. The calculation unit calculates classification information that classifies a motor current change amount, which is a change amount in the motor current, by a DC component of the motor current change amount and a reference phase of an AC component of the motor current change amount, based on a gate signal used when the voltage applicator outputs a drive voltage and the detected value of the motor current. The judgment unit judges an abnormality in the rotor of the synchronous reluctance motor based on the classification information. Effect of the Invention

[0009] The synchronous reluctance motor abnormality detection device according to the present disclosure has the advantage that it is possible to detect an abnormality in the rotor even if the synchronous reluctance motor is not rotating at a constant speed. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing a functional configuration of an abnormality detection device according to an embodiment. [Diagram 2] FIG. 1 is a diagram showing a configuration example of a sensorless control device including an abnormality detection device according to an embodiment; [Diagram 3] FIG. 1 is a cross-sectional view used to explain the structure of a rotor core in a synchronous reluctance motor according to an embodiment. [Figure 4] Diagram showing the change in inductance in a typical synchronous reluctance motor [Diagram 5] FIG. 3 is a diagram showing an example of a circuit configuration of the voltage applicator shown in FIG. 2; [Figure 6] FIG. 3 is a diagram showing an example of a correspondence relationship between the switching state of each phase of the voltage applicator shown in FIG. 2 and the definition of a voltage vector. [Figure 7] A diagram showing the eight switching states and voltage vectors shown in FIG. [Figure 8] FIG. 3 is a diagram for explaining signal processing in the position estimator shown in FIG. 2; [Figure 9] FIG. 9 is a diagram showing a detailed configuration of a current differential information calculation unit shown in FIG. 8 . [Figure 10] FIG. 9 is a diagram showing a DC component and an AC component included in the current differential information output by the current differential information calculation unit shown in FIG. 8. [Figure 11] FIG. 9 is a diagram showing an output waveform of the current differential information calculation unit shown in FIG. 8. [Figure 12] FIG. 9 is a diagram for explaining classification performed by the classifier shown in FIG. [Figure 13] An explanatory diagram of the operation of the classifier shown in FIG. [Figure 14] A block diagram showing the configuration of the phase synchronization calculation unit shown in FIG. [Figure 15] FIG. 9 is a diagram showing output waveforms of each part of the position estimator shown in FIG. 8. [Figure 16]FIG. 1 is a block diagram showing an example of a hardware configuration for implementing the functions of an abnormality detection device according to an embodiment. [Figure 17] FIG. 13 is a block diagram showing another example of a hardware configuration for implementing the functions of the abnormality detection device according to the embodiment. [Figure 18] 1 is a flowchart showing a process flow of an abnormality detection process according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] An abnormality detection device and an abnormality detection method for a synchronous reluctance motor according to an embodiment of the present disclosure will be described in detail below with reference to the accompanying drawings. Hereinafter, the "abnormality detection device for a synchronous reluctance motor" and the "abnormality detection method for a synchronous reluctance motor" will be simply referred to as the "abnormality detection device" and the "abnormality detection method" as appropriate.

[0012] Embodiment FIG. 1 is a diagram showing a functional configuration of an abnormality detection device 50 according to an embodiment. FIG. 2 is a diagram showing a configuration example of a sensorless control device 100 including the abnormality detection device 50 according to an embodiment. As shown in FIG. 1, the abnormality detection device 50 includes a calculation unit 51 and a determination unit 52. As shown in FIG. 2, the sensorless control device 100 includes a current detector 2, a voltage applicator 3, a position estimator 4, a controller 5, and an abnormality determiner 25. The controller 5 includes a current controller 6, a rotating coordinate inverse converter 7, a two-phase to three-phase converter 8, a three-phase to two-phase converter 9, and a rotating coordinate converter 10. In FIG. 1 and FIG. 2, the calculation unit 51 shown in FIG. 1 is configured to include a part of the function of the position estimator 4 shown in FIG. 2, and the determination unit 52 shown in FIG. 1 is configured to include the function of the abnormality determiner 25 shown in FIG. 2. That is, the abnormality detection device 50 according to the embodiment includes the abnormality determiner 25 shown in FIG. 2 and is configured to be able to use the function of the position estimator 4 shown in FIG. 2.

[0013] In FIG. 2, the synchronous reluctance motor 1 is a three-phase synchronous reluctance motor (SynRM) that generates a reluctance torque using the saliency of the rotor. The synchronous reluctance motor 1 is a device driven by a sensorless control device 100, and includes a stator 1a and a rotor 1b disposed inside the stator 1a. The sensorless control device 100 controls the driving of the synchronous reluctance motor 1 without using a speed sensor or a position sensor. Although the details will be described later, the sensorless control device 100 controls the operation of the voltage applicator 3 based on a detected value of a motor current flowing through the synchronous reluctance motor 1 and an estimated value of the rotor position of the synchronous reluctance motor 1 estimated based on the motor current. In addition, the abnormality detection device 50 is applied to the sensorless control device 100 and performs an abnormality detection process for detecting an abnormality in the rotor 1b of the synchronous reluctance motor 1.

[0014] The DC power supply 36 supplies DC power to the voltage applicator 3. The voltage applicator 3 applies a DC voltage V dc is used to generate an AC voltage for driving the motor, and the generated AC voltage is applied to the synchronous reluctance motor 1.

[0015] The current detector 2 detects the motor current i flowing between the voltage applicator 3 and the synchronous reluctance motor 1. u ,i v ,i w Detect the motor current i u ,i v ,i w The detected value of the motor current i is input to the position estimator 4 and the controller 5. u ,i v ,i w are stator currents flowing through each phase of the stator 1a, i.e., the u-phase, v-phase, and w-phase. An example of the current detector 2 is a current transformer. The current detector 2 may detect all three-phase currents, but may also detect currents for any two of the three phases and the remaining phase is the motor current i u ,i v ,i wAlternatively, instead of the current detector 2 in FIG. 2, a bus current flowing through a DC bus (not shown) connecting the voltage applicator 3 and the DC power supply 36 is detected, and the motor current i u ,i v ,i w may be calculated.

[0016] The voltage applicator 3 applies a drive voltage to the synchronous reluctance motor 1. The drive voltage is generated by a gate signal G u ,G v ,G w The gate signal G u ,G v ,G w is the synchronous reluctance motor voltage command v output from the controller 5. u *,v v *,v w *. In this paper, the voltage applicator 3 is assumed to be a two-level three-phase inverter, but is not limited to this. In this paper, the voltage applicator 3 may be a three-level three-phase inverter, or a polyphase two-level or three-level inverter.

[0017] The position estimator 4 receives the motor current i u ,i v ,i w In addition to the detection value, the gate signal G used when the voltage applicator 3 outputs the drive voltage u ,G v ,G w The position estimator 4 receives the motor current i u ,i v ,i w The detection value and the gate signal G u ,G v ,G wand an estimated rotor position is calculated using these. In the following explanation, the rotor position is represented as "θ", and the estimated value of the rotor position θ is represented by adding "^" above "θ". Note that a symbol with "^" above "θ" may also be represented by adding "^" after "θ". Similarly, a symbol with "^" above or after a symbol representing a parameter represents an estimated value of that parameter. The position estimator 4 outputs the estimated rotor position θ^ to the controller 5.

[0018] The controller 5 calculates the motor current i on the rotation coordinate system of the synchronous reluctance motor 1. d ,i q is the motor current command i on the rotating coordinate system. d *,i q Synchronous reluctance motor voltage command v that drives synchronous reluctance motor 1 so that it becomes the value indicated by *. u *,v v *,v w The controller 5 calculates the calculated synchronous reluctance motor voltage command v u *,v v *,v w * is output to voltage applicator 3.

[0019] Returning to the explanation of FIG. 1, the calculation unit 51 receives a gate signal G u ,G v ,G w and motor current i u ,i v ,i w The detection value of the gate signal G u ,G v ,G w and motor current i u ,i v ,i w The judging unit 52 judges an abnormality of the rotor 1b of the synchronous reluctance motor 1 based on the classification information classified by the arithmetic unit 51, and outputs the judgment result J. d Output.

[0020] Next, the necessity and principle of the abnormality detection process in the embodiment will be described. FIG. 3 is a cross-sectional view used to explain the structure of rotor core 70 in synchronous reluctance motor 1 assumed in the embodiment. In FIG. 3, rotor core 70 is configured by laminating a plurality of electromagnetic steel sheets, which are plate materials. Shaft 71 is fitted to the inner diameter side of rotor core 70. Rotor core 70 is formed of a laminated body in which core pieces 73, which are annular thin plates, are stacked. Core pieces 73 can be made by punching out electromagnetic steel sheets, which are thin steel plates, with a press machine. When synchronous reluctance motor 1 is assembled, the stacking direction of the thin plates that make up rotor core 70 is the same as the axial direction of shaft 71.

[0021] A rotor core 70 in which a number of core pieces 73 are laminated has a number of slits 72 that form magnetic barriers. The slits 72 are arc-shaped and protrude toward the shaft hole into which the shaft 71 fits, and are formed from one d-axis side to the other d-axis side with the q-axis as the center. In rotor core 70, the d-axis is an axis through which magnetic flux passes relatively easily, and the q-axis is an axis through which magnetic flux passes relatively less easily. The d-axis and q-axis are magnetically and electrically perpendicular to each other.

[0022] Slit groups 74, each consisting of a plurality of slits 72, are formed at intervals in the circumferential direction of the rotor core 70, the number of which corresponds to the number of poles. Fig. 3 shows an example in which the rotor 1b has four poles, and in Fig. 3, slit groups 74 for the four poles are formed.

[0023] The rotor core 70 must have enough strength to withstand the centrifugal force generated when the synchronous reluctance motor 1 rotates. For this reason, the slits 72 are formed with a center rib 75a that acts as a strength member. In addition to the center rib 75a, each slit 72 other than the outermost periphery is formed with two side ribs 75b that also act as strength members. The center rib 75a and the side ribs 75b can be formed by leaving the center rib 75a and the side rib 75b unpunched when punching out the slits 72 from a thin steel plate. The arrangement of the center rib 75a and the side ribs 75b shown in FIG. 3 is merely an example, and is not limited to this arrangement. Any arrangement may be used as long as the desired strength is obtained.

[0024] Furthermore, in rotor core 70, no slits 72 are formed between each of slit groups 74 and edge portion 76 on the outer periphery of rotor core 70, thereby forming annular portion 77. In rotor core 70, annular portion 77 also acts as a strength member. These strength members, such as center rib 75a, side rib 75b, and annular portion 77, are also called "bridge portions."

[0025] Figure 4 is a diagram showing the change in inductance in a typical synchronous reluctance motor, where the horizontal axis represents the rotor position and the vertical axis represents the magnitude of inductance.

[0026] In a typical synchronous reluctance motor, the inductance changes according to the electrical angle. Specifically, as shown in Fig. 4, the inductance has a characteristic that the maximum value and the minimum value appear twice during one electrical angle rotation. The maximum value of the inductance is the d-axis inductance L d The minimum value of inductance is the q-axis inductance L q That is, the d-axis inductance L d teeth 、 q-axis inductance L q Here, the q-axis inductance L q d-axis inductance L d If the ratio of these is defined as the saliency ratio, then the saliency ratio Ld / L q is greater than 1. This is because the d-axis current i d The q-axis current i q This is because the synchronous reluctance motor 1 is configured so that the interlinkage magnetic flux due to the axial direction is larger than that due to the axial direction.

[0027] As described above, in the synchronous reluctance motor 1, there is a trade-off between the salient pole ratio and the centrifugal strength. For this reason, the synchronous reluctance motor 1 is designed to maximize the salient pole ratio while ensuring sufficient centrifugal strength. However, in a large-capacity application such as a synchronous reluctance motor for a railway vehicle, the size and weight of the rotor 1b of the synchronous reluctance motor 1 are large. For this reason, in this type of large-capacity application, the centrifugal force generated in the rotor 1b is large, and compared to a low-capacity application, there is a high possibility that cracks will occur in strength members such as the center rib 75a, the side ribs 75b, and the annular portion 77.

[0028] When a crack occurs in a strength member such as the center rib 75a, the side rib 75b, or the annular portion 77, the effect is that the d-axis inductance L d , q-axis inductance L q , salient pole ratio L d / L q This appears as an inductance abnormality such as the above. Therefore, if an inductance abnormality is detected, it is possible to detect an abnormality in the rotor 1b. In this paper, an abnormality in the rotor 1b is detected by utilizing the fact that an inductance abnormality appears in the current differential information and classification information used to calculate the estimated rotor position θ^. In other words, the method in this paper detects an abnormality in the rotor 1b by using the current differential information and classification information used to estimate the phase of the rotor position.

[0029] Fig. 5 is a diagram showing an example of a circuit configuration of the voltage applicator 3 shown in Fig. 2. Fig. 5 shows an example of a circuit configuration when the voltage applicator 3 is a three-phase PWM (Pulse Width Modulation) inverter. The voltage applicator 3 includes a leg 30A in which an upper arm semiconductor element UP and a lower arm semiconductor element UN are connected in series, a leg 30B in which an upper arm semiconductor element VP and a lower arm semiconductor element VN are connected in series, and a leg 30C in which an upper arm semiconductor element WP and a lower arm semiconductor element WN are connected in series. The leg 30A, the leg 30B, and the leg 30C are connected in parallel with each other.

[0030] A bus voltage is applied to the voltage applicator 3 through DC buses 35a, 35b. The voltage applicator 3 converts DC power from a DC power source 36, which is supplied through the DC buses 35a, 35b, into AC power, and supplies the converted AC power to the synchronous reluctance motor 1 to drive the synchronous reluctance motor 1. Note that the current detector 2 is omitted in Fig. 5.

[0031] 5 illustrates an example in which the semiconductor elements UP, UN, VP, VN, WP, and WN are metal-oxide-semiconductor field-effect transistors (MOSFETs). Each of the semiconductor elements UP, UN, VP, VN, WP, and WN includes a transistor 30a and a diode 30b connected in anti-parallel to the transistor 30a. "Connected in anti-parallel" means that the anode side of the diode is connected to a first terminal corresponding to the source of the MOSFET, and the cathode side of the diode is connected to a second terminal corresponding to the drain of the MOSFET.

[0032] The semiconductor elements UP, UN, VP, VN, WP, and WN may be, for example, insulated gate bipolar transistors (IGBTs) instead of MOSFETs.

[0033] A connection point 32 between the upper arm semiconductor element UP and the lower arm semiconductor element UN is connected to a first phase, for example, the u-phase, of the synchronous reluctance motor 1. A connection point 33 between the upper arm semiconductor element VP and the lower arm semiconductor element VN is connected to a second phase, for example, the v-phase, of the synchronous reluctance motor 1. A connection point 34 between the upper arm semiconductor element WP and the lower arm semiconductor element WN is connected to a third phase, for example, the w-phase, of the synchronous reluctance motor 1. In the voltage applicator 3, the connection points 32, 33, and 34 form AC terminals.

[0034] Next, the voltage vector output by the voltage applicator 3 will be described. As described above, the voltage applicator 3 is a three-phase PWM inverter, and is a power converter that obtains a desired voltage by PWM controlling the DC power source 36 supplied through DC buses 35a and 35b. The three-phase PWM inverter has two semiconductor elements, upper and lower arms, for each phase, and the two semiconductor elements of the upper and lower arms operate so that one of them is in the ON state. Therefore, in a three-phase triangular wave comparison inverter, there are 2^3 ways, that is, 8 ways of switching states. The gate signal G u ,G v ,G w is a signal that indicates the switching state of the upper arm semiconductor element of the two upper and lower arm semiconductor elements. u ,G v ,G w When the value of is 1, it means that the semiconductor element of the upper arm of the corresponding phase is in a conductive state, and the gate signal G u ,G v ,G w When the value of is 0, it means that the semiconductor element of the lower arm of the corresponding phase is in a conductive state. For example, (G u ,G v ,G w When R1 is 0, R2 is 1, and R2 is 2, R3, and R4 is 3, this means that the semiconductor element in the upper arm of the u-phase is conductive, and the semiconductor elements in the lower arms of the v-phase and w-phase are conductive.

[0035] Here, the voltage vectors in the eight switching states of the voltage applicator 3 are defined as V0 to V7. FIG. 6 is a diagram showing an example of the correspondence between the switching states of each phase of the voltage applicator 3 shown in FIG. 2 and the definitions of the voltage vectors. u ,G v ,G w )=(0,0,0), the applied voltage vector is defined as V0, and (G u ,G v ,G w ) = (1,0,0), the applied voltage vector is defined as V1, and (G u ,G v ,G w )=(1,1,0), the applied voltage vector is defined as V2, and (G u ,G v ,G w ) = (0,1,0), the applied voltage vector is defined as V3. u ,G v ,G w ) = (0,1,1), the applied voltage vector is defined as V4, and (G u ,G v ,G w ) = (0,0,1), the applied voltage vector is defined as V5, and (G u ,G v ,G w ) = (1,0,1), the applied voltage vector is defined as V6, and (G u ,G v ,G w The voltage vector applied under the condition of V(t)=(1,1,1) is defined as V7. Of these eight voltage vectors V0 to V7, the voltage vectors V0 and V7 are referred to as zero voltage vectors, and the rest, that is, the voltage vectors V1 to V6, are referred to as effective voltage vectors. 0~7 Similarly, the effective voltage vectors V1 to V6 are expressed as the effective voltage vector V 1~6 It may be written as:

[0036] Fig. 7 is a diagram showing the eight switching states and voltage vectors shown in Fig. 6. Fig. 7 shows the voltage vectors in each switching state and the conduction state of each semiconductor element of the voltage applicator 3.

[0037] 8 is a diagram for explaining signal processing in the position estimator 4 shown in FIG. 2. The position estimator 4 uses the motor current i u ,i v ,i w and the gate signal G of the voltage applicator 3 u ,G v ,G w and calculates an estimated rotor position θ^, which is an estimate of the position of the rotor of the synchronous reluctance motor 1. Specifically, the position estimator 4 includes a current differential information calculation unit 40, a classifier 41, a DC component remover 42, a three-phase to two-phase converter 43, and a phase synchronization calculation unit 44.

[0038] The current differential information calculation unit 40 receives the gate signal G of the semiconductor element of the upper arm of each phase of the voltage applicator 3. u ,G v ,G w and the motor current i u ,i v ,i w The current differential information calculation unit 40 receives the detection value of the gate signal G u ,G v ,G w and motor current i u ,i v ,i w The current differential information calculation unit 40 calculates current differential information corresponding to each of the effective voltage vectors V1 to V6 based on the detected values ​​of the u-phase, v-phase, and w-phase motor currents i u ,i v ,i w For each of the effective voltage vectors V1 to V6, current differential information corresponding to each of the effective voltage vectors V1 to V6 is calculated. Therefore, the current differential information calculation unit 40 outputs 3×6=18 types of current differential information. That is, the current differential information in this paper is 18 types of current differential information calculated by distinguishing the six types of effective voltage vectors V1 to V6 for each phase.

[0039] Fig. 9 is a diagram showing a detailed configuration of the current differential information calculation unit 40 shown in Fig. 8. The current differential information calculation unit 40 includes a voltage vector determiner 400 that determines the type of the voltage vector output by the voltage applicator 3, and a motor current i u ,i v ,i w and a current differential calculator 401 that calculates current differential information of each phase corresponding to the effective voltage vector using the above.

[0040] Based on the definition shown in FIG. 6, the voltage vector determiner 400 calculates the gate signal G u ,G v ,G w The voltage vector determiner 400 determines the type of the voltage vector output by the voltage applicator 3 based on the gate signal G u ,G v ,G w The type of voltage vector is determined from the value of the voltage vector V 0~7 The voltage vector V 0~7 is output to the current differentiation calculator 401.

[0041] The current differentiation calculator 401 calculates the voltage vector V 0~7 and the motor current i u ,i v ,i w Based on and, the effective voltage vector V 1~6 The current differential calculator 401 calculates the current differential information of each phase corresponding to each of the voltage vectors V 0~7 The type of effective voltage vector and the type of voltage vector from one control cycle ago are stored, and if the same effective voltage vector appears for two or more control cycles, the current differential information for each phase corresponding to the type of effective voltage vector is calculated. The control cycle is set to a value that is sufficiently short compared to the cycle of the triangular wave carrier of the voltage applicator 3 in order to sample the current during application of the effective voltage vector at two or more points.

[0042] The type of voltage vector in the current control period is V NThe type of the voltage vector one control period before is V N In this case, the current differentiation calculator 401 calculates V N The current differential information of the u-phase, v-phase, and w-phase when the uVN / dt", "di vVN / dt", "di wVN / dt", where N is an integer from 1 to 6. The current differential calculator 401 calculates V 1~6 By distinguishing and calculating the six types of effective voltage vectors and the three-phase current differential information, 18 types of current differential information "di uV1~6 / dt", "di vV1~6 / dt", "di wV1~6 / dt" is output.

[0043] Here, a total of 18 types of current differential information output by current differential calculator 401 will be described. The current differential information includes a DC component and an AC component. FIG. 10 is a diagram showing the DC component and the AC component included in the current differential information output by current differential information calculator 40 shown in FIG. 8. In FIG. 10, each of the 18 types of current differential information is associated with a signal name, a formula indicating the DC component, and a formula indicating the AC component. In the "signal name," u, v, and w indicate the corresponding phase of synchronous reluctance motor 1, and V1 to V6 indicate the type of the corresponding effective voltage vector.

[0044] The characteristics of the "DC component" of the current differential information shown in Fig. 10 will be described. If A is defined by the following formula (1), the "DC component" of the current differential information occurs in the phase in the direction of the effective voltage vector with a magnitude of "2 / A", and occurs in phases other than the phase in the direction of the effective voltage vector with a magnitude of "1 / A" and an opposite sign. Therefore, the sum of the DC component of the u phase, the DC component of the v phase, and the DC component of the w phase during application of the same effective voltage vector is zero. Here, V dc is the DC voltage of the DC power supply 36 of the voltage applicator 3.

[0045]

number

[0046] L0 in formula (1) is expressed by the following formula (2). Also, L1 in formula (1) is expressed by the following formula (3). Here, L d is the d-axis inductance of the synchronous reluctance motor 1, and L q is the q-axis inductance of the synchronous reluctance motor 1.

[0047]

number

[0048]

number

[0049] Next, the characteristics of the "AC component" of the current differential information will be described. Here, if the number of the effective voltage vector is N, the AC component of the current differential information of the u phase is expressed by formula (4), the AC component of the current differential information of the v phase is expressed by formula (5), and the AC component of the current differential information of the w phase is expressed by formula (6).

[0050]

number

[0051]

number

[0052]

number

[0053] As shown in equations (4) to (6), the current differential information obtained by applying an effective voltage vector has information on the rotor position θ. The "AC component" column in Fig. 10 shows the expansion of the phases in equations (4) to (6). As is clear from Fig. 10 and equations (4) to (6), the AC components of the current differential information during the application period of the same effective voltage vector have a phase difference of "±2π / 3" from each other, and are characterized by the fact that the respective reference phases shift depending on the application direction of the effective voltage vector. The magnitude of the amplitude of the AC component is the same for all combinations of effective voltage vectors and phases, and is "(1 / A) × (L1 / L0)". In addition, since the magnitude relationship between the d-axis and q-axis inductance is different between an interior permanent magnet synchronous motor (IPMSM) and a synchronous reluctance motor, the value of the cosine function coefficient "(1 / A) × (L1 / L0)" is a positive value in an interior permanent magnet synchronous motor and a negative value in a synchronous reluctance motor.

[0054] In each phase, the current differential information obtained by combinations of effective voltage vectors in a magnetization and demagnetization direction relationship has mutually opposite signs, as represented by the following formulas (7) to (9). In formulas (7) to (9), n is an integer from 1 to 3. The combinations of voltage vectors in a magnetization and demagnetization direction relationship are V1 and V4 in the u-phase, V3 and V6 in the v-phase, and V5 and V2 in the w-phase.

[0055]

number

[0056]

number

[0057]

number

[0058] FIG. 11 is a diagram showing an output waveform of the current differential information calculation unit 40 shown in FIG. 8. FIG. 11 shows a simulation result when current vector control is performed on the synchronous reluctance motor 1 rotating at a low speed, and a triangular wave carrier comparison commonly used for three phases is used to generate a PWM signal to be applied to the voltage applicator 3. For the sake of explanation, the voltage vector numbers V0 and V7 are numbered 0. Here, when focusing on the rotor position and the number of the applied voltage vector, a correlation can be confirmed between the rotor position and the appearance pattern of the voltage vector. During the period when a specific effective voltage vector appears, current differential information corresponding to other effective voltage vectors cannot be obtained, so that in the appearance pattern of an effective voltage vector in which a specific effective voltage vector occurs for a long period of time, the current differential information is fragmentary. Furthermore, there is a characteristic that the timing at which each piece of current differential information can be obtained is different, and the delay amount differs depending on the signal. Due to this characteristic, if signal processing is performed without considering the appearance pattern of the voltage vector, the position sensorless control becomes unstable. Here, "signal processing is performed without taking into consideration the appearance pattern of voltage vectors" refers to, for example, a case where the type of current differential information used to estimate the rotor position is fixed regardless of the type of voltage vector that appears.

[0059] For this reason, the position estimator 4 performs signal processing to generate AC components of continuous current differential information having rotor position information from the fragmentary current differential information. The signal processing method performed by the position estimator 4 will be described below. The current differential information has the characteristics shown in the above formulas (4) to (9). When this characteristic is utilized, the same waveform shape appears in the current differential information under different voltage vector and phase conditions. For this reason, the position estimator 4 uses the waveform shapes that appear under different voltage vector and phase conditions to interpolate the fragmentary current differential information and generate AC components of continuous current differential information.

[0060] Returning to the description of FIG. 8, the classifier 41 calculates classification information based on the current differential information. The classification information is information obtained by classifying the motor current change amount, which is the change amount of the motor current, according to the DC component of the motor current change amount and the reference phase of the AC component of the motor current change amount. Specifically, the classifier 41 classifies the current differential information output by the current differential information calculation unit 40 into one of six types of signals according to the magnitude of the DC component and the reference phase of the AC component. Based on the characteristics of the above formulas (4) to (9), the classifier 41 classifies into six types according to the magnitude of the DC component and the phase of the AC component: group (2 / A, 0°), group (-1 / A, 120°), group (-1 / A, -120°), group (2 / A, -120°), group (-1 / A, 0°), and group (2 / A, 120°).

[0061] FIG. 12 is a diagram for explaining the classification performed by the classifier 41 shown in FIG. 8. FIG. 12 shows the "group", "DC component", "AC component", and "symbol" of each of the six groups classified by the classifier 41. Here, "group" indicates the name of the group, and a group described as group(X, Y°) means a group in which the DC component is X and the reference phase of the AC component is Y°. For example, the reference phase Y in the cosine component "cos(2θ+2π / 3)" of the AC component in FIG. 12 is 2π / 3 [rad] = 120 [°]. The "symbol" indicates signals having the same waveform. For example, in the group (2 / A, 0°), it means that the waveform of the current differential information of the u phase when the effective voltage vector V1 is applied is the same as the waveform of the current differential information of the u phase when the effective voltage vector V4 is applied.

[0062] FIG. 13 is a diagram for explaining the operation of the classifier 41 shown in FIG. 8. The classifier 41 uses the current differential information “di uV1~6 / dt", "di vV1~6 / dt", "di wV1~6When "di / dt" is input, the classifier 41 generates six types of signals based on the classification shown in FIG. 12. Specifically, the classifier 41 prepares variables corresponding to each of the six types of groups, and operates to assign the current differential information to the variable of the group into which the current differential information input to the classifier 41 is classified, while the variables of the other groups retain their previous values. For the sake of explanation, the names of the groups are used as variable names. Group(X,Y°) is a variable of a group whose DC component is X and whose reference phase of the AC component is Y°. For example, the classifier 41 assigns "di uV1 / dt" and "-di uV4 / dt" is substituted, and when an effective voltage vector other than V1 and V4, that is, V2, V3, V5, or V6, is applied, the classifier 41 operates to hold the previous value. Similarly, the classifier 41 assigns "di vV1 / dt" and "-di vV4 / dt" and "di uV3 / dt" and "-di uV6 / dt" is substituted, and when V2 and V5 are applied, the previous value is held.

[0063] Returning to the description of FIG. 8, the DC component remover 42 extracts a DC component from the output of the classifier 41, and subtracts the DC component from the current differential information obtained by applying the latest effective voltage vector, thereby generating a continuous AC component. In the embodiment, an example of extracting a DC component using a three-phase balanced condition will be described. To extract the DC component "1 / A" using the three-phase balanced condition, the following formulas (10) to (14) are used. That is, the DC component remover 42 calculates the sum of the signals of combinations with phases of 0°, 120°, and -120° from the output of the classifier 41, and multiplies the sum by a conversion coefficient to a DC component to calculate the DC component. Here, five types of formulas (10) to (14) are shown, but the DC component remover 42 may perform the calculation using at least one appropriate formula depending on the combination of the latest effective voltage vector and the nearest effective voltage vector having a different number from the latest effective voltage vector.

[0064]

number

[0065]

number

[0066]

number

[0067]

number

[0068]

number

[0069] Specifically, the DC component remover 42 uses an equation from among the equations (10) to (14) that uses the latest effective voltage vector and the nearest effective voltage vector having a different number from the latest effective voltage vector. Here, for example, group (2 / A, 0°) is generated based on the current differential information when the effective voltage vector V1 or V4 is applied, group (2 / A, 120°) is generated based on the current differential information when the effective voltage vector V5 or V2 is applied, and group (2 / A, -120°) is generated based on the current differential information when the effective voltage vector V3 or V6 is applied. Therefore, it can be said that the equation (10) is an equation that uses the effective voltage vector V1 or V4, V5 or V2, and V3 or V6. Similarly, the equation (11) is an equation that uses the effective voltage vector V2 or V5, and V1 or V3 or V4 or V6. Equation (12) is an equation using effective voltage vectors V1 or V4 and V2 or V5. Equation (13) is an equation using effective voltage vectors V1 or V4 and V3 or V6. Equation (14) is an equation using effective voltage vectors V2 or V5 and V3 or V6.

[0070] For example, if the combination of the latest effective voltage vector and the most recent effective voltage vector having a different number from the latest effective voltage vector is V1 and V2, at least one formula using these voltage vectors can be selected from formulas (10) to (14). The formulas using the effective voltage vectors V1 and V2 are formulas (11) and (12). Therefore, the DC component remover 42 calculates the DC component "1 / A" using at least one of formulas (11) and (12). When multiple formulas are used, the DC component remover 42 can calculate the DC component "1 / A" using an average value of the calculation results of each of the multiple formulas.

[0071] The DC component remover 42 uses the extracted DC component to subtract the DC component from the current differential information obtained by applying the latest effective voltage vector, thereby calculating the AC component of the latest current differential information. The DC component remover 42 can calculate the AC component of the latest current differential information using the following formulas (15) to (17). The DC component remover 42 selects one of the formulas (15) to (17) based on the type of the latest voltage vector.

[0072]

number

[0073]

number

[0074]

number

[0075] The DC component remover 42 outputs the calculation results, group (0, 0°), group (0, 120°), and group (0, -120°), to the three-phase to two-phase converter 43. The outputs of the DC component remover 42, group (0, 0°), group (0, 120°), and group (0, -120°), are continuous AC components including rotor position information. A method of calculating the rotor position using these AC components will be described below. To calculate the rotor position from AC components having a phase difference of ±2π / 3 from each other, there are a method of performing three-phase to two-phase conversion on these AC components and performing arctangent calculation, and a method of estimating the rotor position by performing phase synchronous calculation on the three-phase to two-phase conversion result. Here, the method of estimating the rotor position by phase synchronous calculation will be described as an example.

[0076] The three-phase to two-phase converter 43 calculates the α-axis AC component α and β-axis AC component β, which are AC components on two orthogonal axes. The three-phase to two-phase converter 43 calculates the α-axis AC component α and β-axis AC component β using the following formula (18), and outputs the calculated α-axis AC component α and β-axis AC component β to the phase synchronization calculation unit 44.

[0077]

number

[0078] The phase synchronization calculation unit 44 estimates the rotor position of the synchronous reluctance motor 1 based on the α-axis AC component α and the β-axis AC component β output from the three-phase to two-phase converter 43. Specifically, the phase synchronization calculation unit 44 estimates the rotor position of the synchronous reluctance motor 1 by performing a phase synchronization calculation on the α-axis AC component α and the β-axis AC component β.

[0079] Fig. 14 is a block diagram showing the configuration of the phase synchronization calculation unit 44 shown in Fig. 8. The phase synchronization calculation unit 44 includes a phase error calculation unit 441, a proportional integral (PI) controller 442, an integrator 443, and proportional controllers 444 and 445.

[0080] The phase error calculation unit 441 receives the α-axis AC component α and the β-axis AC component β output from the three-phase to two-phase converter 43, and the estimated rotor position 2θ^ output from the integrator 443. The phase error calculation unit 441 calculates the phase error Δi AC The phase error calculation unit 441 calculates the calculated phase error Δi AC *Δ2θ is output to the PI controller 442.

[0081]

number

[0082] Here, "Δi AC " is expressed by the following equation (20).

[0083]

number

[0084] The PI controller 442 receives the phase error Δi AC *Δ2θ is input. The PI controller 442 calculates the phase error Δi AC *Output the estimated speed 2ω^ so that Δ2θ becomes zero.

[0085] The integrator 443 integrates the estimated speed 2ω^ output by the PI controller 442, and outputs the integrated value as the estimated rotor position 2θ^. The estimated rotor position 2θ^ output by the integrator 443 is fed back to the phase error calculation unit 441.

[0086] In the above formula (19), when "2θ>2θ^", the phase error Δi AC *Since Δ2θ is a positive value, the estimated speed 2ω^ and the estimated rotor position 2θ^ are corrected in the increasing direction. Also, when "2θ<2θ^", the phase error Δi AC *Since Δ2θ is a negative value, the estimated speed 2ω^ and the estimated rotor position 2θ^ are corrected to decrease. Ultimately, "2θ=2θ^" is obtained, and the phase and frequency of the AC component of the current differential information of the synchronous reluctance motor 1 are estimated. In this way, the phase synchronization calculation unit 44 takes the form of a phase locked loop (PLL).

[0087] The phase synchronization calculation unit 44 inputs the estimated rotor position 2θ^ to a proportional unit 444 and multiplies it by 0.5 to calculate an estimated rotor position θ^. The phase synchronization calculation unit 44 also inputs the estimated speed 2ω^ to a proportional unit 445 and multiplies it by 0.5 to calculate an estimated speed ω^.

[0088] FIG. 15 is a diagram showing output waveforms of each part of the position estimator 4 shown in FIG. 8. In FIG. 15, the operating conditions are the same as those in FIG. 11, and are conditions under which the current differential information is fragmentary. In the "rotor position" in the first row from the top of FIG. 15, the true position of the rotor and the estimated position output by the phase synchronization calculation unit 44 are shown. In the second to fourth rows from the top of FIG. 15, the output of the current differential information calculation unit 40 is shown. In the fifth row from the top of FIG. 15, the output of the classifier 41 is shown. In the sixth row from the top of FIG. 15, the output of the DC component remover 42 is shown. In the seventh row from the top of FIG. 15, the output of the three-phase to two-phase converter 43 is shown. In the eighth row from the top of FIG. 15, the numbers of the voltage vectors applied at each time point are shown. In FIG. 15, as in FIG. 11, the voltage vector numbers V0 and V7 are numbered 0 for the sake of explanation.

[0089] It can be seen from Fig. 15 that the classifier 41 generates six types of signals based on the classification shown in Fig. 12. The output of the DC component remover 42 has zero DC components and is an AC component expressed on two orthogonal axes vibrating at an angle twice that of the rotor position. The position estimator 4 estimates the rotor position by performing phase synchronous calculation on the output of the three-phase to two-phase converter 43.

[0090] Returning to the explanation of FIG. 2, the three-phase to two-phase converter 9 of the controller 5 detects the motor current i u ,i v ,i w The three-phase to two-phase converter 9 converts the motor current i u ,i v ,i w The motor current i on the stationary two-phase coordinate system α ,i β The three-phase to two-phase converter 9 converts the motor current i α ,i β is output to the rotating coordinate converter 10.

[0091] The rotating coordinate converter 10 receives the motor current i output from the three-phase to two-phase converter 9. α ,i βand the estimated rotor position θ^ output by the position estimator 4. The rotating coordinate converter 10 converts the motor current i α ,i β The motor current i on the rotating coordinate system d ,i q The rotating coordinate converter 10 converts the motor current i d ,i q is output to the current controller 6.

[0092] The current controller 6 receives the motor current command i d *,i q * and the motor current i d ,i q The motor current command i d * is a command for the d-axis drive current that indicates the armature current component in the d-axis direction at which the magnetic resistance of the rotor of the synchronous reluctance motor 1 is the smallest. q * is a command for the q-axis drive current, which indicates the armature current component in one axis direction, which is perpendicular to the d-axis. The current controller 6 controls the motor current i d ,i q is the motor current command i d *,i q *, and the synchronous reluctance motor voltage command v d *,v q The current control in the current controller 6 is, for example, PI control. The current controller 6 calculates the synchronous reluctance motor voltage command v d *,v q * is output to the rotation coordinate inverse converter 7.

[0093] The rotating coordinate inverse converter 7 receives the synchronous reluctance motor voltage command v d *,v q The rotating coordinate inverse converter 7 uses the estimated rotor position θ^ to convert the synchronous reluctance motor voltage command v in the rotating coordinate system calculated by the current controller 6 into d *,v q * is the synchronous reluctance motor voltage command v on the stationary two-phase coordinate system α *,vβ The rotating coordinate inverse converter 7 converts the synchronous reluctance motor voltage command v α *,v β * is output to the two-phase to three-phase converter 8.

[0094] The two-phase to three-phase converter 8 receives a synchronous reluctance motor voltage command v α *,v β The two-phase to three-phase converter 8 receives the synchronous reluctance motor voltage command v on the stationary two-phase coordinate system. α *,v β * is the synchronous reluctance motor voltage command v on the three-phase coordinate system for driving the synchronous reluctance motor 1. u *,v v *,v w Convert to *.

[0095] Fig. 16 is a block diagram showing an example of a hardware configuration for realizing the functions of anomaly detection device 50 according to an embodiment. When realizing the functions of anomaly detection device 50 according to an embodiment, as shown in Fig. 16, a configuration including a processor 300 for performing calculations, a memory 302 for storing a program read by processor 300, an interface 304 for inputting and outputting signals, and a display 306 for displaying detection results can be used.

[0096] The processor 300 is an example of a computing means. The processor 300 may be a computing means called a microprocessor, a microcomputer, a microcontroller, a CPU (Central Processing Unit), or a DSP (Digital Signal Processor). Examples of the memory 302 include non-volatile or volatile semiconductor memories such as RAM (Random Access Memory), ROM (Read Only Memory), flash memory, EPROM (Erasable Programmable ROM), and EEPROM (registered trademark) (Electrically EPROM), magnetic disks, flexible disks, optical disks, compact disks, mini disks, and DVDs (Digital Versatile Discs).

[0097] The memory 302 stores a program for executing the functions of the anomaly detection device 50 according to the embodiment. The processor 300 receives and transmits necessary information via the interface 304, executes the program stored in the memory 302, and refers to the data stored in the memory 302, thereby performing the above-mentioned processing. The results of calculations by the processor 300 can be stored in the memory 302. The results of processing by the processor 300 can also be displayed on the display 306. The display 306 may be provided outside the anomaly detection device 50.

[0098] Moreover, in order to realize the functions of the abnormality detection device 50 according to the embodiment, the configuration shown in Fig. 17 may be used. Fig. 17 is a block diagram showing another example of a hardware configuration for realizing the functions of the abnormality detection device 50 according to the embodiment. In Fig. 17, the processor 300 and memory 302 shown in Fig. 16 are replaced with a processing circuit 303.

[0099] The processing circuit 303 may be a single circuit, a composite circuit, an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a combination of these. Information input to the processing circuit 303 and information output from the processing circuit 303 can be exchanged via an interface 304.

[0100] 18 is a flowchart showing a process flow of the abnormality detection process according to the embodiment. The operation of FIG. 18 will be described in association with the calculation unit 51 and the determination unit 52 which are components of the abnormality detection device 50 shown in FIG.

[0101] The calculation unit 51 receives the gate signal G u ,G v ,G w and motor current i u ,i v ,i wThe voltage vector V generated by the voltage applicator 3 based on the detected value 0~7 The effective voltage vector V 1~6 (Step S11). The calculation unit 51 also calculates classification information based on the current differential information calculated in step S11 (Step S12). Furthermore, the calculation unit 51 calculates the deviation between the value in the current control cycle and the value in the previous control cycle for each piece of classification information calculated in step S12 (Step S13). The determination unit 52 compares the absolute value of the deviation with a threshold value (Step S14). The threshold value is an arbitrary real value, and is stored in advance in the memory 302. The threshold value can be determined based on the classification information acquired when the rotor 1b is normal, for example.

[0102] If the absolute value of at least one deviation in each classification information exceeds the threshold value (step S14, Yes), the judgment unit 52 judges that the rotor 1b is abnormal (step S15). If the absolute values ​​of all deviations are equal to or less than the threshold value (step S14, No), the judgment unit 52 judges that the rotor 1b is normal (step S16). After the processes of steps S15 and S16, the judgment unit 52 outputs the judgment result J d is displayed on the display 306 (step S17). When the process of step S17 ends, the process returns to step S11, and the process from step S11 is repeated.

[0103] In the judgment process of step S14, when the absolute value of the deviation is equal to the threshold value, the judgment is "No", but the judgment may be "Yes". In other words, when the absolute value of the deviation is equal to the threshold value, the judgment may be "Yes" or "No".

[0104] The above process flow will be supplemented. The process flow shown in FIG. 18 can be implemented, for example, when the sensorless control device 100 is started. When the sensorless control device 100 is started, the synchronous reluctance motor 1 is often accelerating to increase its rotation speed, and the rotation speed of the synchronous reluctance motor 1 is not constant. As described above, in the conventional technology, the synchronous reluctance motor 1 needs to rotate at a constant speed. For this reason, in the conventional technology, it is difficult to detect an abnormality in the rotor 1b when the sensorless control device 100 is started. In contrast, in the abnormality detection device 50 according to the embodiment, the synchronous reluctance motor 1 does not need to rotate at a constant speed, so it is possible to detect an abnormality in the rotor 1b when the sensorless control device 100 is started.

[0105] As described above, the abnormality detection device according to the embodiment is applicable to a sensorless control device that includes a voltage applicator that applies a drive voltage to a synchronous reluctance motor and controls the operation of the voltage applicator based on a detection value of a motor current flowing through the synchronous reluctance motor and an estimate of a rotor position of the synchronous reluctance motor estimated based on the motor current. The abnormality detection device according to the embodiment includes a calculation unit and a determination unit. The calculation unit calculates classification information that classifies a motor current change amount, which is a change amount of the motor current, by a DC component of the motor current change amount and a reference phase of an AC component of the motor current change amount, based on a gate signal used when the voltage applicator outputs a drive voltage and the detection value of the motor current. The determination unit determines an abnormality of the rotor of the synchronous reluctance motor based on the classification information. Since the abnormality detection device according to the embodiment has no restriction on the rotation speed of the synchronous reluctance motor, it is possible to detect an abnormality of the rotor even if the synchronous reluctance motor does not rotate at a constant speed. Furthermore, since the abnormality detection device according to the embodiment can detect an abnormality of the rotor when the sensorless control device is started up, it is possible to quickly detect an abnormality of the rotor.

[0106] Furthermore, the abnormality detection device according to the embodiment can utilize part of the functions of a position estimator that calculates an estimated rotor position. The position estimator includes a current differential information calculation unit that calculates current differential information of each phase corresponding to an effective voltage vector among the voltage vectors generated by the voltage applicator based on the gate signal and the detection values ​​of the motor current, and a classifier that calculates classification information based on the current differential information. By utilizing the functions of the current differential information calculation unit and the classifier, it is possible to easily realize the configuration of the abnormality detection device.

[0107] In the above process, the current differential information may be 18 types of current differential information calculated by distinguishing between six types of effective voltage vectors for each phase, and the classification information may be 6 types of classification information calculated by classifying the 18 types of current differential information by the magnitude of the DC component, the sign of the DC component, and the reference phase of the AC component. The determination unit calculates the deviation between the value in the current control cycle and the value in the most recent control cycle for each of the six types of classification information, and outputs a determination result that the rotor is abnormal if at least one deviation exceeds a threshold value.

[0108] In the anomaly detection device according to the embodiment, the calculation unit may include a DC component remover that removes DC components from the classification information classified by the classifier. This DC component remover can utilize the function of the position estimator. In this configuration, the determination unit can determine an anomaly in the rotor based on the classification information from which the DC components have been removed.

[0109] In the above process, the classification information can be three types of classification information obtained by classifying the 18 types of current differential information according to the reference phase of the AC component. For each of the three types of classification information from which the DC component has been removed, the determination unit calculates the deviation between the value in the current control cycle and the value in the previous control cycle, and can output a determination result indicating that the rotor is abnormal if at least one deviation exceeds a threshold value.

[0110] The abnormality detection method according to the embodiment is applicable to a sensorless control device that includes a voltage applicator that applies a drive voltage to a synchronous reluctance motor and controls the operation of the voltage applicator based on a detection value of a motor current flowing through the synchronous reluctance motor and an estimate of a rotor position of the synchronous reluctance motor estimated based on the motor current. The abnormality detection method according to the embodiment can be a processing procedure including a calculation step and a determination step. In the calculation step, a process is performed to calculate classification information that classifies the motor current change amount, which is the change amount of the motor current, by a DC component of the motor current change amount and a reference phase of an AC component of the motor current change amount, based on a gate signal used when the voltage applicator outputs a drive voltage and a detection value of the motor current. In the determination step, a process is performed to determine an abnormality of the rotor based on the classification information. In the abnormality detection method according to the embodiment, there is no restriction on the rotation speed of the synchronous reluctance motor, so it is possible to detect an abnormality of the rotor even if the synchronous reluctance motor is not rotating at a constant speed. In addition, in the abnormality detection method according to the embodiment, an abnormality of the rotor can be detected at the start of a control device that performs sensorless control, so it is possible to quickly detect an abnormality of the rotor.

[0111] The configurations shown in the above embodiments are merely examples, and may be combined with other known technologies. Parts of the configurations may be omitted or modified without departing from the spirit of the invention. [Explanation of symbols]

[0112] 1 Synchronous reluctance motor, 1a stator, 1b rotor, 2 current detector, 3 voltage applicator, 4 position estimator, 5 controller, 6 current controller, 7 rotating coordinate inverse converter, 8 two-phase to three-phase converter, 9, 43 three-phase to two-phase converter, 10 rotating coordinate converter, 25 abnormality judger, 30a transistor, 30b diode, 30A, 30B, 30C leg, 32, 33, 34 connection point, 35a, 35b DC bus, 36 DC power source, 40 current differential information calculation unit, 41 classifier, 42 DC component remover, 44 phase synchronization calculation unit, 50 abnormality detection device, 51 calculation unit, 52 judgment unit, 70 rotor core, 71 shaft, 72 slit, 73 core fragment, 74 slit group, 75a center rib, 75b side rib, 76 edge, 77 Circular ring portion, 100 sensorless control device, 300 processor, 302 memory, 303 processing circuit, 304 interface, 306 display, 400 voltage vector determiner, 401 current differential calculator, 441 phase error calculator, 442 PI controller, 443 integrator, 444, 445 proportional devices, UP, UN, VP, VN, WP, WN semiconductor elements.

Claims

1. An abnormality detection device for a synchronous reluctance motor is applied to a sensorless control device which includes a voltage applicator that applies a drive voltage to a synchronous reluctance motor, and controls an operation of the voltage applicator based on a detection value of a motor current flowing through the synchronous reluctance motor and an estimated value of a rotor position of the synchronous reluctance motor estimated based on the motor current, comprising: a calculation unit that calculates classification information obtained by classifying a motor current change amount, which is a change amount of the motor current, according to a DC component of the motor current change amount and a reference phase of an AC component of the motor current change amount, based on a gate signal used when the voltage applicator outputs the drive voltage and a detection value of the motor current; a determination unit that determines an abnormality in a rotor of the synchronous reluctance motor based on the classification information; An abnormality detection device for a synchronous reluctance motor comprising:

2. The calculation unit is a current differential information calculation unit that calculates current differential information of each phase corresponding to an effective voltage vector among the voltage vectors generated by the voltage applicator based on the gate signal and the detection value of the motor current; a classifier that calculates the classification information based on the current differential information; 2. The abnormality detection device for a synchronous reluctance motor according to claim 1, further comprising:

3. The current differential information is 18 types of current differential information calculated by distinguishing six types of effective voltage vectors for each phase.

3. The abnormality detection device for a synchronous reluctance motor according to claim 2.

4. The classification information is six types of classification information obtained by classifying the 18 types of current differential information according to the magnitude of the DC component, the sign of the DC component, and the reference phase of the AC component.

4. The abnormality detection device for a synchronous reluctance motor according to claim 3.

5. The determination unit calculates a deviation between a value in a current control cycle and a value in an immediately previous control cycle for each of the six types of classification information, and outputs a determination result indicating that the rotor is abnormal if at least one of the deviations exceeds a threshold value.

5. The abnormality detection device for a synchronous reluctance motor according to claim 4.

6. the calculation unit includes a DC component remover that removes a DC component from the classification information classified by the classifier, The determination unit determines an abnormality in the rotor based on the classification information from which the DC component has been removed.

3. The abnormality detection device for a synchronous reluctance motor according to claim 2.

7. The current differential information is 18 types of current differential information calculated by distinguishing six types of effective voltage vectors for each phase, The classification information is three types of classification information obtained by classifying the 18 types of current differential information according to the reference phase of the AC component.

7. The abnormality detection device for a synchronous reluctance motor according to claim 6.

8. The determination unit calculates a deviation between a value in a current control cycle and a value in the previous control cycle for each of the three types of classification information, and outputs a determination result indicating that the rotor is abnormal when at least one of the deviations exceeds a threshold value.

8. The abnormality detection device for a synchronous reluctance motor according to claim 7.

9. A method for detecting an abnormality in a synchronous reluctance motor, which is applied to a sensorless control device including a voltage applicator that applies a drive voltage to a synchronous reluctance motor, and which controls an operation of the voltage applicator based on a detection value of a motor current flowing through the synchronous reluctance motor and an estimated value of a rotor position of the synchronous reluctance motor estimated based on a previous motor current, comprising: a calculation step of calculating classification information obtained by classifying a motor current change amount, which is a change amount of the motor current based on a gate signal used when the voltage applicator outputs the drive voltage, by a DC component of the motor current change amount and a reference phase of an AC component of the motor current change amount; a determination step of determining whether or not there is an abnormality in the rotor of the synchronous reluctance motor based on the classification information; A method for detecting an abnormality in a synchronous reluctance motor, comprising:

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