Motor control unit and control method

Abstract

To provide a motor control unit capable of improving the accuracy of the estimation even in a transient state where the d-axis current or q-axis current is fluctuating by accurately calculating the transient components when estimating magnet temperature or magnet flux, and a control method.SOLUTION: The motor control unit for driving a motor by an inverter includes: a transient component calculation unit that calculates a q-axis magnetic flux differential based on the difference between a q-axis magnetic flux command value and a q-axis magnetic flux detection value, or the difference between a q-axis current command value and a q-axis current detection value; a d-axis magnetic flux estimation unit that calculates d-axis magnetic flux estimate based on a q-axis voltage value, q-axis current, electrical angular velocity, and the q-axis magnetic flux differential value; and a magnet temperature calculation unit that calculates a magnet temperature estimate based on the d-axis magnetic flux estimate.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a motor control device and a control method. [Background technology]

[0002] Conventional techniques related to motor control are known, for example, as described in Patent Document 1 and Patent Document 2. Patent Document 1 discloses a drive device for a permanent magnet synchronous motor that estimates the magnetic flux amount or magnet temperature of a magnet of the permanent magnet synchronous motor based on a voltage command value and rotation speed information of the permanent magnet synchronous motor. Patent Document 2 discloses an estimation method that performs coordinate conversion of an armature current to a current on a γ-δ axis consisting of the γ axis and a δ axis perpendicular to the γ axis based on a rotor position and a γ axis in which an estimated total armature flux linkage is generated, and estimates the temperature or magnetic flux of a permanent magnet based on a control command for the synchronous machine and the current on the γ-δ axis. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6978602 [Patent Document 2] JP 2013-198340 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the conventional technology described in Patent Document 1, the magnet flux estimation calculation unit estimates the magnet flux by subtracting from the q-axis voltage the product of the resistance value and the q-axis current, the product of the q-axis inductance and the q-axis current differential value, and the product of the electrical angular velocity, the d-axis inductance and the d-axis current, and dividing the subtraction by the electrical angular velocity. On the other hand, in order to estimate the magnet flux with high accuracy even in a transient state in which the d-axis current or the q-axis current is fluctuating, it is necessary to accurately calculate the product of the q-axis inductance and the q-axis current differential value, which is a component that fluctuates during a transient state (transient component) in the estimation calculation. Due to the influence of noise present in the current detection value, large noise appears in the differential value, making it difficult to accurately calculate the transient component. However, Patent Document 1 does not disclose anything about the calculation of the transient component, and since an error is expected to occur in the magnet flux estimation value in a transient state, it is considered that there is room for improvement.

[0005] In the conventional technology described in Patent Document 2, the d-axis magnetic flux, which is the sum of the magnet magnetic flux and the product of the d-axis inductance and the d-axis current, is estimated by subtracting the product of the resistance value and the q-axis current and the product of the q-axis inductance and the q-axis current differential value from the q-axis voltage, and dividing the result by the electrical angular velocity. In addition, the γ-axis, which is the direction in which the total armature interlinkage magnetic flux is generated, is estimated based on the calculated d-axis magnetic flux, and the armature current is coordinate-transformed into a current on the γ-δ-axis consisting of the γ-axis and the δ-axis, which is perpendicular to the γ-axis, and the magnet temperature or magnet magnetic flux is calculated based on the control command for the synchronous machine and the current on the γ-δ-axis. However, Patent Document 2 does not disclose anything about the calculation of the q-axis inductance and the q-axis current differential value, which are transient components. That is, in Patent Document 2, an error occurs in the estimated value of the d-axis magnetic flux in a transient state, and it is expected that an error also occurs in the estimated value of the magnet temperature or magnet magnetic flux, so it is considered that there is room for improvement.

[0006] The present invention has been made in consideration of the above, and has an object to provide a motor control device and control method that can improve estimation accuracy by accurately calculating transient components when estimating magnet temperature or magnet magnetic flux, even in a transient state in which the d-axis current or q-axis current is fluctuating. [Means for solving the problem]

[0007] The present application includes multiple means for solving the above problems. One example is a motor control device that drives a motor by an inverter, and includes a transient component calculation unit that calculates a q-axis flux differential value based on the difference between a q-axis flux command value and a q-axis flux detection value, or the difference between a q-axis current command value and a q-axis current detection value, a d-axis flux estimation unit that calculates a d-axis flux estimate value based on the q-axis voltage value, the q-axis current, the electrical angular velocity, and the q-axis flux differential value, and a magnet temperature calculation unit that calculates a magnet temperature estimate value based on the d-axis flux estimate value. Effect of the Invention

[0008] According to the present invention, by accurately calculating the transient component when estimating the magnet temperature or magnet magnetic flux, it is possible to improve the estimation accuracy even in a transient state in which the d-axis current or q-axis current is fluctuating. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram illustrating a schematic configuration of a motor control device. [Diagram 2] FIG. 1 is a diagram showing a schematic structure of a PM motor. [Diagram 3] FIG. 2 is a diagram showing the relationship between the rotor position and the phase of each winding of the stator. [Figure 4] FIG. 2 is a diagram illustrating a configuration of an inverter and a current detection unit. [Diagram 5] 6 is a diagram illustrating a relationship between a PWM carrier signal and a voltage command value. [Figure 6] FIG. 4 is a diagram illustrating an example of the configuration of a voltage command value calculation unit. [Figure 7] FIG. 13 is a diagram illustrating another example of the configuration of the voltage command value calculation unit. [Figure 8] FIG. 4 is a functional block diagram showing the processing contents of a magnet temperature estimation unit. [Figure 9] FIG. 4 is a functional block diagram showing an example of processing contents of a voltage detection unit. [Figure 10] FIG. 4 illustrates an example of the configuration of a transient component calculation unit. [Figure 11] FIG. 13 is a diagram showing an example of the waveform of a magnet temperature estimate value when transient components are ignored. [Figure 12] FIG. 13 is a diagram showing an example of the waveform of a magnet temperature estimated value when a q-axis magnetic flux differential value, which is a transient component, is calculated from a q-axis current detection value based on a difference method. [Figure 13] FIG. 4 is a diagram showing an example of a waveform of a magnet temperature estimation value according to the first embodiment. [Figure 14] FIG. 11 is a functional block diagram showing the processing contents of a magnet temperature estimation unit according to the second embodiment. [Figure 15] FIG. 4 is a functional block diagram showing a configuration example of a transient component calculation unit. [Figure 16] 11 is a diagram showing an example of characteristics of a q-axis magnetic flux value and a q-axis inductance with respect to a q-axis current value. FIG. [Figure 17] FIG. 13 is a functional block diagram showing the processing contents of a magnet temperature estimation unit according to the third embodiment. [Figure 18] FIG. 4 is a functional block diagram showing the processing contents of a transient component calculation unit. [Figure 19] FIG. 13 is a functional block diagram showing another example of the configuration of the transient component calculation unit. [Figure 20] FIG. 13 is a functional block diagram showing another configuration example of the magnet temperature estimation unit. [Figure 21] FIG. 13 is a functional block diagram showing the processing contents of a transient component calculation unit in another configuration example of the magnet temperature estimation unit. [Figure 22] FIG. 13 is a diagram showing an example of the waveform of a magnet temperature estimate value when transient components are ignored. [Figure 23] FIG. 13 is a diagram showing an example of the waveform of a magnet temperature estimate value when the effect of magnetic saturation is not taken into consideration in calculating a transient component. [Figure 24] FIG. 13 is a diagram showing an example of a waveform of a magnet temperature estimate value according to the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, the embodiments of the present invention will be described in detail with reference to the drawings. Note that in the embodiments of the present invention described below, various components do not necessarily have to exist independently of each other, and it is acceptable for multiple components to be formed as one member, for one component to be formed by multiple members, for one component to be a part of another component, or for part of one component to overlap with part of another component.

[0011] <First embodiment> A first embodiment of the present invention will be described with reference to FIGS.

[0012] (Motor control device 100) FIG. 1 is a diagram illustrating a schematic configuration of a motor control device.

[0013] In FIG. 1, a motor control device 100 includes a control unit 10, an electric motor (PM motor) 20, an inverter 30, a current detection unit 50, and an angle sensor 60 such as a resolver or an encoder.

[0014] Although not shown, a mechanism for mechanically or magnetically transmitting mechanical output is connected to the PM motor 20, and the motor control device 100 controls the rotation speed or torque of the PM motor 20 to a desired value.

[0015] Although this embodiment does not limit the operating principle of the electric motor 20, the following description will be given by way of example of a permanent magnet synchronous motor (PMSM) having a permanent magnet in the rotor as the electric motor 20. Various types of electric motors are applicable as the electric motor 20, and the subject of this disclosure is an electric motor having a characteristic in which the magnetic flux of the permanent magnet changes depending on the temperature of the rotor.

[0016] The inverter 30 has a DC voltage source 120 such as a battery and a bridge circuit made up of switching elements, and outputs a voltage by switching the switching elements in response to an input drive signal. Assuming that the switching operation of the switching elements is ideally switched without delay, the voltage output from the inverter 30 is a pulsed voltage. Using the well-known concept of pulse width modulation, the pulsed voltage can be regarded as an AC voltage. In pulse width modulation, it is common to make the cycle of turning on and off the switching elements, that is, the switching frequency, sufficiently high with respect to the frequency of the equivalent AC voltage (corresponding here to the rotation frequency of the single-phase motor). However, it is also possible to consider the fundamental wave component of the pulsed voltage. For example, when the switching frequency is close to the rotation frequency of the PM motor, such as about 1 to 3 times, it can be considered that the fundamental wave component of the pulsed voltage is applied to the PM motor 20. Therefore, in this embodiment, the output voltage of the inverter 30 is an AC waveform.

[0017] Note that instead of a DC voltage source, an AC power source may be converted to DC power by rectification, etc. Alternatively, a DC / DC converter may be used that controls a DC voltage source to a different voltage.

[0018] The control unit 10 has a current command value calculation unit 11, a voltage command value calculation unit 12, a PWM signal generation unit 14, a coordinate conversion unit 13, an angular velocity calculation unit 15, and a magnet temperature estimation unit 40.

[0019] The current command value calculation unit 11 calculates and outputs a d-axis current command value and a q-axis current command value based on the rotation speed command value or the torque command value.

[0020] The coordinate conversion unit 13 receives the current detection value, which is information about the current flowing through the PM motor obtained by the current detection unit 50, and the motor electrical angle detection value obtained by the angle sensor 60, converts it from the three-phase UVW axes to the dq axes, the definition of which will be described later, and outputs the d-axis current detection value and the q-axis current detection value.

[0021] An angular velocity calculation unit 15 receives the motor electrical angle detection value and outputs the electrical angular velocity.

[0022] The voltage command value calculation unit 12 generates a d-axis voltage command value and a q-axis voltage command value based on the d-axis current command value and the q-axis current command value output by the current command value calculation unit 11, the d-axis current detection value and the q-axis current detection value output by the coordinate conversion unit 13, and the electrical angular velocity output by the angular velocity calculation unit 15.

[0023] The PWM signal generating unit 14 generates and outputs a PWM signal that controls the on / off of the switching elements that constitute the inverter 30 based on the d-axis voltage command value and the q-axis voltage command value output by the voltage command value calculating unit 12 .

[0024] In FIG. 1, the rotation speed command value and the torque command value are shown inside the control unit 10, but they may be configured to be obtained from, for example, a higher-level control system (not shown) or another control system.

[0025] In addition, the magnet temperature estimator 40 receives as input the d-axis voltage command value, the q-axis voltage command value, the d-axis current command value, the q-axis current command value, the d-axis current detection value, the q-axis current detection value, and the electrical angular velocity, but may be configured to calculate the magnet temperature estimate using only some of the values ​​instead of inputting all of the values.

[0026] (PM motor 20) FIG. 2 is a diagram illustrating a schematic structure of the PM motor 20. As shown in FIG.

[0027] In FIG. 2, the PM motor 20 is composed of a stator 21 and a rotor 22. The stator 21 has a plurality of stator poles 28 in which windings (coils) 25 are wound around a stator core (stator iron core) 26. The rotor 22 has a permanent magnet 27. Note that, in FIG. 2, an example is shown in which the number of magnetic poles of the stator (also called the number of slots) is six and the number of magnetic poles of the rotor 22 is two, but this is not limiting, and the numbers of magnetic poles of the stator 21 and the rotor 22 can be freely selected, and the number of magnetic poles of the stator and the rotor may not be equal. In addition, the connection of the plurality of windings may be parallel or serial. In this embodiment, the windings 25 of the opposing stator poles 28 are connected in series to form one phase, and the PM motor 20 is described as being composed of three-phase windings.

[0028] The stator magnetic poles 28 are generated in the manner of an electromagnet by passing a current through the windings 25, and the polarity (N pole, S pole) can be changed depending on the direction of the current through the windings 25. In this embodiment, the rotation angle (rotation angle position) of the rotor 22 when the stator magnetic poles 28 become S poles when a positive DC current is passed through the windings 25 and the N pole of the permanent magnet 27 of the rotor 22 is attracted is defined as zero degrees. In the following description, the rotation angle position of the rotor is represented as rotor position θd. When there are multiple windings 28, any one of them is defined as the reference position. In this embodiment, the winding 25 located on the right side in FIG. 2 (i.e., the winding closest to the description of "U phase") is defined as the reference position. In addition, the counterclockwise rotation direction of the rotor 22 is defined as positive rotation.

[0029] The processing within the motor control device 100 utilizes information on the rotor position θd of the rotor 22 of the PM motor 20, and the position information will be described as being detected by a resolver, encoder, or the like as the angle sensor 60. Naturally, it may also be configured to obtain the position information by position sensorless control using a position estimation means that outputs an estimated rotational angle position of the PM motor 20 from the current flowing through the PM motor 20 and the voltage applied to the PM motor 20.

[0030] (Explanation of coordinate axes) Here, the definition of the coordinate axes will be described. Fig. 3 is a diagram showing the relationship between the rotor position θd and the phase of each winding 25 of the stator 21.

[0031] The three-phase windings U, V, and W are arranged with a difference of 120 degrees in electrical angle. The direction of the main magnetic flux of the permanent magnet provided in the rotor 22 is defined as the d-axis, and the dq-axis is defined as the q-axis that is electrically 90 degrees (electrical angle 90 degrees) ahead of the d-axis in the direction of rotation. The dq-axis is a rotating coordinate system. The definition of the d-axis can also be said to be the rotation angle position at which the magnetic flux of the permanent magnet 27 that links with the reference winding 25 is maximum.

[0032] (Inverter 30) FIG. 4 is a diagram showing the configuration of the inverter 30 and the current detection unit 50. As shown in FIG.

[0033] As shown in FIG. 4, inverter 30 has inverter module 131, DC voltage source 120, and gate driver circuit 123. Here, the output of DC voltage source 120 is DC voltage Edc. Inverter module 131 has switching elements 32a-32f (for example, semiconductor switching elements such as IGBT and MOS-FET) and free wheel diodes connected in parallel thereto. Switching elements 32a-32f are collectively referred to as "switching elements 32." A shunt resistor 25 is connected in series to DC voltage source 120. This serves to protect switching elements 32 so that excessive current does not flow.

[0034] These switching elements 32 are configured as upper and lower arms of each phase by connecting two sets of switching elements 32 in series. In FIG. 4, the upper and lower arms of the U phase are configured by the switching elements 32a and 32b, the V phase by the switching elements 32c and 32d, and the W phase by the switching elements 32e and 32f. The connection points of the upper and lower arms of each phase are connected to the motor 20. The gate driver circuit 123 receives a pulse-shaped drive signal (details will be described later) output by the PWM signal generating unit 14 shown in FIG. 1, and outputs drive signals 34a to 34f based on the pulse-shaped drive signal. A known technique can be used as a method for generating the drive signal. For example, as shown in FIG. 5, the drive signal can be generated from the magnitude relationship between the triangular wave carrier signal and the voltage command value of each phase. In the inverter module 131, the switching of each switching element 32 is controlled based on these drive signals 34a to 34f.

[0035] Depending on the switching state of the upper and lower arms, the voltage of each phase of the inverter 30 becomes either a DC voltage Edc or zero voltage. In the inverter 30, switching is performed at a frequency sufficiently higher than the frequency of the AC voltage appearing in the motor 20, so the output voltage of each phase of the inverter 30 can be freely adjusted by changing the switching ratio (switching duty) of the upper and lower arms. In other words, a three-phase AC voltage of any frequency can be applied to the motor 20, thereby realizing variable speed driving and torque control of the motor 20.

[0036] (Current detection unit 50) The current detection unit 50 detects the currents flowing in the U and W phases of the three-phase AC current flowing from the inverter 30 to the motor 20, and outputs the results as AC current detection values ​​Iu, Iw. Of course, it is possible to detect the AC current of all phases, but according to Kirchhoff's first law, if two of the three phases can be detected, the remaining phase can be calculated from the detected two phases. The current detection unit 50, such as a CT (current transformer), can be provided on the lower arm of the inverter module 131.

[0037] As the current detection unit 50, for example, a phase shunt current method can be adopted in which a shunt resistor is added to the lower arm of the inverter module 131 instead of a CT, and the current of each phase flowing through the inverter 30 is detected from the current flowing through the shunt resistor. Instead of or in addition to the current detection unit 50, a single shunt current detection method can be adopted in which the current on the AC side of the inverter 30 is detected from the DC current flowing through a shunt resistor 135 added to the DC side of the inverter 30. The single shunt current detection method utilizes the fact that the current flowing through the shunt resistor 135 changes over time depending on the energization state of the switching element 32 that constitutes the inverter 30.

[0038] (Method of driving PM motor 20) When driving a motor having permanent magnets 27 in rotor 22, maximum torque can be obtained with minimum current by generating magnetic flux from winding 25 at a position 90 electrical degrees ahead of the magnetic flux from permanent magnets 27 in the direction of rotation. Driving in this way not only makes it possible to reduce the size and weight of the motor, but also has the effect of making inverter 30 smaller.

[0039] The aforementioned d-axis and q-axis can also be said to be the magnet flux axis and the q-axis the winding flux axis, and it is particularly important to appropriately control the current on the q-axis. Separating the current flowing through the motor into a field component and a torque component on the rotating coordinate axis, and controlling the phase and magnitude of the voltage to control the motor's rotation speed or torque, is generally called vector control. Note that, although control is performed on the dq axes as a driving method for PM motors, known coordinate transformation techniques can be used to convert from the three-phase UVW axes to the dq axes.

[0040] (Example of configuration of voltage command value calculation unit 12: voltage command value calculation unit 12a) FIG. 6 is a diagram illustrating an example of the configuration of the voltage command value calculation unit.

[0041] Various conventional techniques (eg, configurations and means described in JP-A-2005-39912) can be applied to the functions of the voltage command value calculation unit 12, and an example of the configuration using these is shown in FIG. 6 as a voltage command value calculation unit 12a.

[0042] In FIG. 6, a voltage command value calculation unit 12a receives the d-axis and q-axis current command values ​​(Id* and Iq*) calculated by the current command value calculation unit 11 and the motor electrical angular velocity ωe, and performs vector calculation according to the following (Equation 1) and (Equation 2) to obtain a d-axis voltage command value Vd* and a q-axis voltage command value Vq*.

[0043] Vd*=R×Id**-ωe×Lq×Iqf** …(Formula 1) Vq*=R×Iq**+ωe×Ld×Idf**+ωe×Φd0 …(Formula 2) In the above (Equation 1) and (Equation 2), R is the winding resistance value per phase of the motor 6, Ld is the d-axis inductance, Lq is the q-axis inductance, and Φd0 is the magnet magnetic flux. Φd0 is also called the induced voltage constant.

[0044] In Fig. 6, a configuration of d-axis current controller 114a and q-axis current controller 114b is used to ensure that the dq-axis currents flow as commanded. In the circuit configuration in Fig. 6, 91 is a subtractor that calculates the difference between the current command values ​​(Id* and Iq*) and their detected values ​​(Idc and Iqc), 92 is a proportional circuit that adds a predetermined gain to the difference, 94 is an integrator, and 90 is an adder that adds the proportional and integral components to calculate the proportional integral value. The output is the d-axis and q-axis current command values ​​(Id** and Iq**).

[0045] Id** and Iq** are multiplied by the winding resistance value R per phase of the motor 6 in multipliers 92g and 92i to obtain the first terms on the right-hand sides of the above (Equation 1) and (Equation 2).

[0046] In the second term on the right side of the above (Equation 1) and (Equation 2), the d-axis and q-axis current command values ​​(Idf** and Iqf**) are values ​​obtained by filtering the q-axis and d-axis current command values ​​(Iq** and Id**) with the filter circuits 98a and 98b in Fig. 6. Idf** and Iqf** are multiplied by the q-axis inductance Lq and the d-axis inductance Ld in multipliers 92h and 92j, respectively, and are also multiplied by the motor electrical angular velocity ωe to obtain the second term on the right side of the above (Equation 1) and (Equation 2). Furthermore, multiplier 92k multiplies the motor electrical angular velocity ωe by the d-axis inductance Ld to obtain the third term on the right side of the above (Equation 2).

[0047] A subtractor 91f subtracts the output of the multiplier 92h from the output of the multiplier 92g to obtain the d-axis voltage command value Vd* of the above (Equation 1). An adder 90d obtains the sum of the output of the multiplier 92i, the output of the multiplier 92j, and the output of the multiplier 92k to obtain the q-axis voltage command value Vq* of the above (Equation 2).

[0048] The circuit configuration example in Fig. 6 is characterized in that the d-axis current controller 114a and the q-axis current controller 114b are connected in series to the voltage calculation in the voltage command value calculation unit 12a, and that there are first-order lag filters (low-pass filters) 98a and 98b having a cutoff frequency equivalent to the electrical time constant of the motor. These establish an inverse model of the motor, which has the effect of realizing ideal vector control even when the calculation period of the control unit 10 is restricted. The voltage command value calculation unit 12a causes the current detection value to follow the current command value with a delay of the response time constant Tc. The response time constant Tc can be adjusted by the control parameters of the d-axis current controller 114a and the q-axis current controller 114b.

[0049] (Another Configuration Example of Voltage Command Value Calculation Unit 12: Voltage Command Value Calculation Unit 12b) FIG. 7 is a diagram illustrating another example of the configuration of the voltage command value calculation unit.

[0050] Other conventional technologies (for example, the configurations and means described in JP 2021-151003 A) can be applied as the functions of the voltage command value calculation unit 12, and an example configuration using this is shown in FIG. 7 as voltage command value calculation unit 12b.

[0051] In this configuration example, a dq-axis magnetic flux command value and a magnetic flux detection value are calculated from a dq-axis current command value and a current detection value, and the magnetic flux detection value is controlled to be the magnetic flux command value.

[0052] In order to accurately control a motor with a high magnetic flux density in order to make it smaller, it is necessary to take into account the effects of magnetic saturation. The d-axis and q-axis inductances vary depending on the operating state due to the effects of magnetic saturation, but if this phenomenon is ignored and the d-axis and q-axis inductances used in control are kept constant, controllability will deteriorate. As a countermeasure to this, there is a method of changing the d-axis and q-axis inductances used in control depending on the operating state. However, doing so will complicate the control system, and the number of constants used in inductance-related calculations in particular will increase, making parameter identification difficult and increasing the load on the control device. In the circuit configuration of Figure 7, the magnetic flux command value and magnetic flux detection value that take into account the effects of magnetic saturation are calculated, and the magnetic flux detection value is controlled so that it is equal to the magnetic flux command value, making it possible to accurately control the motor without complicating the control system.

[0053] A d-axis magnetic flux command value calculation unit 80 calculates a d-axis magnetic flux command value Φd* from the d-axis current command value Id* and the q-axis current command value Iq*. Similarly, a q-axis magnetic flux command value calculation unit 81 calculates a q-axis magnetic flux command value Φq* from the d-axis current command value Id* and the q-axis current command value Iq*. A d-axis magnetic flux detection value calculation unit 82 calculates a d-axis magnetic flux detection value Φdc from the d-axis current detection value Idc and the q-axis current detection value Iqc. Similarly, a q-axis magnetic flux detection value calculation unit 83 calculates a q-axis magnetic flux detection value Φqc from the d-axis current detection value Idc and the q-axis current detection value Iqc.

[0054] A voltage command value calculation unit 84 calculates a d-axis voltage command value Vd* and a q-axis voltage command value Vq* so that the d-axis magnetic flux detection value Φdc is equal to the d-axis magnetic flux command value Φd*, and the q-axis magnetic flux detection value Φqc is equal to the q-axis magnetic flux command value Φq*. The voltage command value calculation unit 12b makes the magnetic flux detection value follow the magnetic flux command value with a delay of a response time constant Tc. The response time constant Tc can be adjusted by a control parameter of the voltage command value calculation unit 84.

[0055] (Challenges for improving torque precision) The motor control device 100 controls the rotation speed or torque of the PM motor 20 to a desired value, but when driving a PM motor, if the temperature of the magnet changes, the magnetic flux changes depending on the temperature, so there is a problem that torque accuracy will deteriorate unless some kind of response is taken.

[0056] If the magnet temperature can be measured, it is possible to improve torque accuracy by adjusting the current command value according to the temperature. However, it is difficult to directly connect a temperature sensor to the magnet inside the rotor due to issues with durability and productivity. Therefore, estimating the magnet temperature is an effective solution.

[0057] In addition, in motor control devices for driving electric vehicles such as electric cars, the torque command value fluctuates depending on the driving conditions, and transient states in which the d-axis current or q-axis current fluctuate frequently occur. Furthermore, with the aim of suppressing motor vibration and noise, preventing slippage and driving electric vehicles stably, development of control that constantly fluctuates the torque command value is progressing, and the frequency of transient states is increasing. Therefore, it is necessary to accurately estimate the magnet temperature not only in the steady state but also in the transient state.

[0058] Therefore, in this embodiment, the transient component calculation unit calculates a q-axis magnetic flux differential value based on the difference between the q-axis magnetic flux command value and the q-axis magnetic flux detection value or the difference between the q-axis current command value and the q-axis current detection value, calculates a d-axis magnetic flux estimate value based on the q-axis voltage value, the q-axis current value, the electrical angular velocity, and the q-axis magnetic flux differential value, and calculates a magnet temperature estimate value based on the d-axis magnetic flux estimate value, thereby accurately calculating the transient component when estimating the magnet temperature or magnet magnetic flux, and improving the estimation accuracy even in a transient state where the d-axis current or q-axis current is fluctuating. This point will be described in more detail below.

[0059] (Configuration and operation of magnet temperature estimation unit) FIG. 8 is a functional block diagram showing the processing contents of the magnet temperature estimation unit 40.

[0060] Here, we will explain the operation when estimating the magnet temperature while the motor is running. The relationship between the q-axis voltage value Vq, motor resistance value R, q-axis current value Iq, d-axis magnetic flux Φd, q-axis magnetic flux Φq, and electrical angular velocity ωe can be expressed by the following (Equation 3).

[0061] Vq=R×Iq+dΦq / dt+ωe×Φd…(Formula 3) Here, the d-axis magnetic flux Φd and the q-axis magnetic flux Φq can be expressed by the following (Equation 4) and (Equation 5) using the d-axis inductance Ld, the d-axis current value Id, the magnet magnetic flux Φd0, the q-axis inductance Lq, and the q-axis current value Iq.

[0062] Φd=Ld×Id+Φd0 …(Equation 4) Φq=Lq×Iq…(Formula 5) Here, the magnet magnetic flux Φd0 changes in value depending on the magnet temperature. Therefore, the d-axis magnetic flux Φd also changes in value depending on the magnet temperature.

[0063] Therefore, the d-axis magnetic flux Φd is estimated while the motor is being driven, and the magnet temperature can be estimated from the relationship between the d-axis magnetic flux and the magnet temperature. The d-axis magnetic flux estimation unit 41a calculates an estimated value Φd_est of the d-axis magnetic flux Φd by the following (Equation 6) based on the above (Equation 3).

[0064] Φd_est=(Vq-R×Iq-dΦq / dt) / ωe …(Equation 6) When the d-axis magnetic flux estimation value Φd_est is calculated using the above (Equation 6), the q-axis voltage value Vq in the above (Equation 6) is set to the q-axis voltage command value Vq*. Alternatively, as shown in FIG. 9, the inverter output voltage is measured by the voltage sensor 70, the voltage detection value is input to the control unit 10, and the coordinate conversion unit 13a converts the voltage detection value from the three-phase UVW axes to the dq axes to obtain the d-axis voltage detection value Vdc and the q-axis voltage detection value Vqc, so that the q-axis voltage value Vq may be set to the q-axis voltage detection value Vqc. The d-axis current value Iq in Equation 6 may be set to the q-axis current detection value Iqc or the q-axis current command value Iq*. The calculation of the q-axis magnetic flux differential value dΦq / dt, which is a transient component, will be described later.

[0065] The d-axis magnetic flux estimate value Φd_est is input to the magnet magnetic flux calculation unit 43a to calculate the magnet temperature estimate value. The magnet magnetic flux estimate value Φd0_est is calculated by the following (Equation 7) based on the above (Equation 4).

[0066] Φd0_est=Φd_est-Ld×Id…(Equation 7) The d-axis current value Id in the above (Equation 7) may be the d-axis current detection value Idc or the d-axis current command value Id*. Next, using the correspondence between the magnet magnetic flux Φd0 and the magnet temperature, the magnet temperature estimate is calculated from the magnet magnetic flux estimate Φd0_est.

[0067] As an example of a method for calculating a magnet temperature estimate from the magnet flux estimate value Φd0_est, the magnet temperature versus magnet flux Φd0 is measured or calculated by electromagnetic field simulation in advance and stored, and a table of magnet temperatures with magnet flux Φd0 as a parameter is created and used during estimation. Alternatively, the relationship between magnet flux Φd0 and magnet temperature may be expressed as a formula and used during estimation. In this embodiment, the calculation method is not important as long as the magnet temperature estimate can be calculated from the magnet flux estimate value Φd0_est.

[0068] As another method of calculating the magnet temperature estimated value in the magnet flux calculation unit 43a, the magnet temperature estimated value can be calculated directly from the d-axis magnetic flux estimated value Φd_est without calculating the magnet flux estimated value Φd0_est.

[0069] The d-axis magnetic flux Φd varies depending on the magnet temperature, the d-axis current value Id, and the q-axis current value Iq. Therefore, the magnet temperature estimate is calculated using the correspondence relationship between the d-axis magnetic flux estimate Φd_est, the d-axis current value Id, the q-axis current value Iq, and the magnet temperature.

[0070] As an example of a method of calculating the magnet temperature estimate from the d-axis magnetic flux estimate value Φd_est, the d-axis current value Id, and the q-axis current value Iq, there is a configuration in which the magnet temperatures for the d-axis magnetic flux Φd, the d-axis current value Id, and the q-axis current value Iq are measured or calculated and stored in advance by electromagnetic field simulation, and a magnet temperature table is created with the magnet magnetic flux Φd0, the d-axis current value Id, and the q-axis current value Iq as parameters, and used during estimation. In this embodiment, it is sufficient to be able to calculate the magnet temperature estimate from the d-axis magnetic flux estimate value Φd_est, and the calculation method is not important.

[0071] (Configuration and operation of the transient component calculation unit) In order to estimate the magnet temperature with high accuracy in a transient state where the d-axis current or q-axis current is fluctuating, it is necessary to accurately calculate the q-axis magnetic flux differential value dΦq / dt, which is the transient component in the above (Equation 6). The q-axis magnetic flux differential value dΦq / dt can be expressed by the following (Equation 8) based on the above (Equation 5).

[0072] dΦq / dt=Lq×dIq / dt …(Equation 8) The q-axis magnetic flux differential value dΦq / dt can be calculated by multiplying the derivative of the q-axis current value by the q-axis inductance. One possible method for calculating the derivative of the q-axis current value is to use only the q-axis current detection value and use the difference method, in which the difference between the past sampled value and the current value is divided by the time difference between the sampled values. With the difference method, because division is done by the time difference between the sampled values, which is a very small value, the effects of noise contained in the q-axis current detection value are significant. As a result, an error occurs in the q-axis magnetic flux differential value dΦq / dt, deteriorating the estimation accuracy of the transient state.

[0073] Therefore, in this embodiment, the difference ΔIq between the q-axis current command value Iq* and the q-axis current detection value Iqc is input to a transient component calculation unit 42a, which calculates the q-axis magnetic flux differential value dΦq / dt.

[0074] FIG. 10 is a diagram showing an example of the configuration of the transient component calculation unit 42a.

[0075] 10, the transient component calculation unit 42a utilizes the fact that the q-axis current command value Iq* and the q-axis current detection value Iqc follow each other with a delay of the response time constant Tc. If the reciprocal of the response time constant Tc is the response angular frequency ωc and the response delay is approximated as a first-order delay relationship, the transfer function of the q-axis current command value Iq* and the q-axis current detection value Iqc is expressed by the following (Equation 9) using the Laplace operator s.

[0076] Iqc=1 / {1+s×(1 / ωc)}×Iq* …(Equation 9) Moreover, the following (Equation 10) can be obtained from the above (Equation 9).

[0077] s×Iqc=ωc×(Iq*-Iqc) …(Equation 10) Since s × Iqc on the left side of the above equation (10) indicates the derivative of the q-axis current detection value Iqc, the derivative value dIqc / dt of the q-axis current detection value Iqc can be calculated by multiplying the difference ΔIq between the q-axis current command value Iq* and the q-axis current detection value Iqc by the response angular frequency ωc.

[0078] The transient component calculation unit 42a calculates the q-axis magnetic flux differential value dΦq / dt by the following (Equation 11).

[0079] dΦq / dt=Lq×ωc×ΔIq…(Equation 11) The q-axis magnetic flux differential value dΦq / dt can be calculated without performing an operation such as dividing by the time difference of the sampling values, which is a very small value that causes the differential method to be significantly affected by noise.

[0080] (Effects of this embodiment) The effects of the present embodiment configured as above will be described.

[0081] Figures 11 to 13 are diagrams showing example waveforms of magnet temperature estimates when the handling of transient components is changed. Figures 11 to 13 show example waveforms of magnet temperature estimates when the torque is changed in steps from 0% to 100% under the condition that the magnet temperature is 100°C.

[0082] 11 shows an example of the waveform of the magnet temperature estimated value when a configuration that ignores transient components is adopted as a comparative example of the present invention. A configuration that ignores transient components corresponds to, for example, a case where the magnet temperature estimator 40a is operated with the q-axis magnetic flux differential value set to zero. In this case, a large estimated temperature error occurs at the timing when the torque changes from 0% to 100%.

[0083] 12 shows an example of the waveform of the magnet temperature estimated value when the q-axis magnetic flux differential value, which is a transient component, is calculated from the q-axis current detection value based on the difference method, as another comparative example to the present invention. In this case, the estimated temperature error can be reduced at the timing when the torque changes from 0% to 100%, but since the q-axis magnetic flux differential value is significantly affected by noise in the q-axis current detection value, a large error also occurs in the estimated temperature.

[0084] Fig. 13 shows an example of the waveform of the magnet temperature estimation value in this embodiment. As shown in Fig. 13, in this embodiment, the q-axis magnetic flux differential value can be calculated with little effect of noise, so the estimated temperature error at the timing when the torque changes from 0% to 100% is small, and the estimated temperature error caused by noise can also be suppressed.

[0085] <Second embodiment> A second embodiment of the present invention will be described with reference to FIGS.

[0086] This embodiment shows a case where a different configuration is used for calculating the transient component in the magnet temperature estimation unit 40 in the first embodiment. Note that in this embodiment, only the differences from the first embodiment will be described, and the same members as in the first embodiment will be given the same reference numerals and the description will be omitted as appropriate. (Magnet temperature estimation section 40b) FIG. 14 is a functional block diagram showing the processing contents of the magnet temperature estimation unit according to the present embodiment.

[0087] As shown in FIG. 14, a transient component calculation unit 42b of a magnet temperature estimation unit 40b in this embodiment calculates a q-axis magnetic flux differential value using as input the difference ΔΦq between the q-axis magnetic flux command value Φq* and the q-axis magnetic flux detection value Φqc.

[0088] A q-axis magnetic flux command value calculation unit 44b calculates a q-axis magnetic flux command value Φq* from the d-axis current command value Id* and the q-axis current command value Iq*.

[0089] A q-axis magnetic flux detection value calculation unit 45b calculates a q-axis magnetic flux detection value Φqc from the d-axis current detection value Idc and the q-axis current detection value Iqc.

[0090] The q-axis magnetic flux command value calculation unit 44b and the q-axis magnetic flux detection value calculation unit 45b may be configured, for example, to calculate and store the q-axis magnetic flux Φq relative to the d-axis current value Id and the q-axis current value Iq in advance by measuring or by electromagnetic field simulation, and to create a table of the q-axis magnetic flux Φq with the d-axis current value Id and the q-axis current value Iq as parameters, and use the table for estimation. Alternatively, the relationship between the q-axis magnetic flux Φq relative to the d-axis current value Id and the q-axis current value Iq may be expressed as a formula, and used for estimation. In this embodiment, it is sufficient to calculate the q-axis magnetic flux Φq from the d-axis current value Id and the q-axis current value Iq, and the calculation method is not important.

[0091] (Transient component calculation unit 42b) FIG. 15 is a functional block diagram showing the processing contents of the transient component calculation unit.

[0092] 15, the transient component calculation unit 42b calculates the q-axis magnetic flux differential value by utilizing the fact that the q-axis magnetic flux command value Φq* and the q-axis magnetic flux detection value Φqc follow each other with a delay of the response time constant Tc. If the reciprocal of the response time constant Tc is the response angular frequency ωc and the response delay is approximated as a first-order delay relationship, the transfer function of the q-axis magnetic flux command value Φq* and the q-axis magnetic flux detection value Φqc is expressed by the following (Equation 12) using the Laplace operator s.

[0093] Φqc=1 / {1+s×(1 / ωc)}×Φq* …(Equation 12) Moreover, the following (Equation 13) can be obtained from the above (Equation 12).

[0094] s×Φqc=ωc×(Φq*-Φqc) …(Equation 13) Since s×Φqc on the left side of the above (Equation 13) indicates the derivative of the q-axis magnetic flux detection value Φqc, the derivative value dΦqc / dt of the q-axis magnetic flux detection value Φqc can be calculated by multiplying the difference ΔΦq between the q-axis magnetic flux command value Φq* and the q-axis magnetic flux detection value Φqc by the response angular frequency ωc. The transient component calculation unit 42b calculates the q-axis magnetic flux derivative value dΦq / dt using the following (Equation 14).

[0095] dΦq / dt=ωc×ΔΦq …(Equation 14) The other configurations are similar to those of the first embodiment.

[0096] (Effects of this embodiment) In the present embodiment configured as above, it is possible to suppress the influence of noise in the same manner as in the first embodiment.

[0097] Moreover, in this embodiment, the calculation load is small and the q-axis magnetic flux differential value dΦq / dt can be calculated. As in the first embodiment, the influence of noise can be suppressed.

[0098] This embodiment is particularly suitable when the configuration based on the magnetic flux command value and the measured value shown in Fig. 7 is adopted for the voltage command value calculation unit 12. The q-axis magnetic flux command value calculation unit 44b and the q-axis magnetic flux detection value calculation unit 45b in Fig. 14 can be omitted, and instead the q-axis magnetic flux command value Φq* and the q-axis magnetic flux detection value Φqc can be obtained from the q-axis magnetic flux command value calculation unit 81 and the q-axis magnetic flux detection value calculation unit 83 in Fig. 7. That is, the additional configuration and calculation load are small, and it is possible to calculate the transient component.

[0099] <Third embodiment> A third embodiment of the present invention will be described with reference to FIGS.

[0100] This embodiment shows a case where a different configuration is used for calculating the transient component in the magnet temperature estimation unit 40 in the first embodiment. Note that in this embodiment, only the differences from the first embodiment will be described, and the same members as in the first embodiment will be given the same reference numerals and the description will be omitted as appropriate.

[0101] FIG. 16 is a diagram showing an example of characteristics of the q-axis magnetic flux Φq and the q-axis inductance Lq with respect to the q-axis current value Iq.

[0102] In order to make motors more compact, the magnetic flux density is being increased. This trend is particularly noticeable in electric vehicles such as electric cars. In motors with high magnetic flux density, the effect of magnetic saturation is strongly manifested in the characteristics of magnetic flux and inductance relative to the current.

[0103] As shown in Figure 16, as the q-axis current value Iq increases from zero, the q-axis magnetic flux Φq initially increases linearly, but gradually the effects of magnetic saturation appear, the increase saturates, and the characteristic becomes nonlinear. Here, as shown in Figure 16, the slope of the q-axis magnetic flux Φq with respect to the q-axis current value Iq is the q-axis inductance Lq. Therefore, as the q-axis current value Iq increases from zero, the q-axis inductance Lq remains almost constant or gradually decreases, and the value rapidly decreases above the current value at which the effects of magnetic saturation become significant.

[0104] In motors that are significantly affected by magnetic saturation, if the magnetic saturation characteristics of the q-axis magnetic flux Φq and the magnetic characteristics of the q-axis inductance explained in FIG. 16 are not taken into consideration when calculating the transient component, the q-axis magnetic flux differential value dΦq / dt, an error will occur in the calculation of the transient component and the estimation accuracy of the magnet temperature will deteriorate.

[0105] (Magnet temperature estimation section 40c) FIG. 17 is a functional block diagram showing the processing contents of the magnet temperature estimation unit according to the present embodiment.

[0106] In FIG. 17, in a magnet temperature estimation unit 40c according to this embodiment, a transient component calculation unit 42c receives as input the q-axis current command value Iq*, the d-axis current detection value Idc, and the q-axis current detection value Iqc, and calculates the q-axis magnetic flux differential value taking into account the influence of magnetic saturation.

[0107] (Transient component calculation unit 42c) FIG. 18 is a functional block diagram showing the processing contents of the transient component calculation unit 42c.

[0108] As shown in Fig. 18, the transient component calculation unit 42c multiplies the difference ΔIq between the q-axis current command value Iq* and the d-axis current detection value Idc by the response angular frequency ωc to calculate the q-axis current differential value dIq / dt, as in the first embodiment. The transient component calculation unit 42c further includes a q-axis inductance calculation unit 421c that receives the d-axis current detection value Idc and the q-axis current detection value Iqc as inputs, and calculates the q-axis inductance Lq taking into account the magnetic saturation characteristics. The q-axis magnetic flux differential value dΦq / dt is calculated from the product of the q-axis inductance Lq and the q-axis current differential value dIq / dt. This allows the transient component to be calculated accurately even in a motor that is significantly affected by magnetic saturation, and improves the accuracy of magnet temperature estimation during a transient state.

[0109] An example of the configuration of the q-axis inductance calculation unit 421c is to measure or calculate and store the q-axis inductance Lq for the d-axis current value Id and the q-axis current value Iq in advance by electromagnetic field simulation, create a table of the q-axis inductance Lq with the d-axis current value Id and the q-axis current value Iq as parameters, and use the table for estimation. Alternatively, the relationship between the q-axis inductance Lq for the d-axis current value Id and the q-axis current value Iq may be expressed as a formula, and used for estimation.

[0110] (Another Configuration Example of the Transient Component Calculation Unit: Transient Component Calculation Unit 42d) It is to be noted that the transient component calculation section may have another configuration.

[0111] FIG. 19 is a diagram illustrating another example of the configuration of the transient component calculation unit.

[0112] In FIG. 19, a transient component calculation unit 42d calculates the q-axis current differential value dIq / dt from the q-axis current detection value Iqc using a differentiator, and in this respect differs from the transient component calculation unit 42c shown in FIG.

[0113] (Another Configuration Example of the Magnet Temperature Estimation Unit: Magnet Temperature Estimation Unit 40e) Moreover, the magnet temperature estimating section may also have another configuration.

[0114] FIG. 20 is a diagram showing another configuration example of the magnet temperature estimator.

[0115] In FIG. 20, the magnet temperature estimation unit 40e includes a q-axis magnetic flux detection value calculation unit 45e that inputs the d-axis current detection value Idc and the q-axis current detection value Iqc and outputs the q-axis magnetic flux detection value Φqc, and the transient component calculation unit 42e inputs the q-axis magnetic flux detection value Φqc and calculates the q-axis magnetic flux differential value dΦq / dt, and this point differs from the magnet temperature estimation unit 40c shown in FIG. 17.

[0116] (Transient component calculation unit 42e) FIG. 21 is a functional block diagram showing the processing contents of the transient component calculation unit 42e.

[0117] 21, a transient component calculation unit 42e calculates a q-axis magnetic flux differential value dΦq / dt from the q-axis magnetic flux detection value Φqc using a differentiator. A q-axis magnetic flux detection value calculation unit 45e calculates the q-axis magnetic flux Φq in consideration of the magnetic saturation characteristics illustrated in FIG.

[0118] An example of the configuration of the q-axis magnetic flux detection value calculation unit 45e is to measure or calculate and store the q-axis magnetic flux Φq relative to the d-axis current value Id and the q-axis current value Iq in advance by electromagnetic field simulation, and create a table of the q-axis magnetic flux Φq with the d-axis current value Id and the q-axis current value Iq as parameters to be used during estimation. Alternatively, the relationship between the q-axis magnetic flux Φq relative to the d-axis current value Id and the q-axis current value Iq may be expressed as a formula to be used during estimation.

[0119] When the configuration based on the magnetic flux command value and the measured value shown in FIG. 7 is adopted for the voltage command value calculation unit 12, the q-axis magnetic flux detection value calculation unit 45e in FIG. 20 can be omitted and instead the q-axis magnetic flux detection value Φqc can be obtained from the q-axis magnetic flux detection value calculation unit 83 in FIG. 7, thereby realizing a similar function.

[0120] The other configurations are similar to those of the first embodiment.

[0121] (Effects of this embodiment) The effects of the present embodiment configured as above will be described.

[0122] Figures 22 to 24 are diagrams showing example waveforms of magnet temperature estimates when the handling of transient components is changed. Figures 22 to 24 show example waveforms of magnet temperature estimates when the torque is changed in steps from 0% to 50% and from 50% to 100% in a motor that is significantly affected by magnetic saturation and the magnet temperature is 100°C.

[0123] 22 shows an example of the waveform of the magnet temperature estimated value when a configuration that ignores transient components is adopted as a comparative example to the present invention. A configuration that ignores transient components corresponds to a case where the magnet temperature estimator 40c operates with the q-axis magnetic flux differential value set to zero. In this case, large estimated temperature errors occur at the timing when the torque changes from 0% to 50% and at the timing when it changes from 50% to 100%.

[0124] FIG. 23 shows an example of the waveform of the magnet temperature estimated value when a configuration that does not consider the influence of magnetic saturation is adopted as another comparative example of the present invention. The configuration that does not consider the influence of magnetic saturation corresponds to a case where the q-axis inductance Lq is constant in the magnet temperature estimator 40c. In this case, the estimated temperature error can be reduced at the timing when the torque changes from 0% to 50%, but a large estimated temperature error occurs at the timing when the torque changes from 50% to 100%. This is because, under conditions where the torque increases and the q-axis current also increases, the q-axis inductance decreases due to the influence of magnetic saturation, and even in such a case, if the transient component is calculated with the q-axis inductance Lq constant, the calculated value of the transient component becomes excessive, resulting in an estimated temperature error.

[0125] Fig. 24 shows an example of the waveform of the magnet temperature estimated value in this embodiment. In this embodiment, the q-axis inductance Lq is calculated or the q-axis magnetic flux detection value Φqc is calculated taking into account the influence of magnetic saturation according to the d-axis current value and the q-axis current value that change with the torque, so that the estimated temperature error is small both at the timing when the torque changes from 0% to 50% and at the timing when the torque changes from 50% to 100%, as shown in Fig. 13.

[0126] <Additional Notes> The present invention is not limited to the above-mentioned examples, and various modifications are possible without departing from the spirit of the present invention. For example, the above-mentioned embodiment has been described in detail to explain the present invention in an easily understandable manner, and the present invention is not necessarily limited to those having all of the described configurations.

[0127] In addition, the above-mentioned configurations, functions, processing units, processing procedures, etc. may be realized in part or in whole by hardware, for example, by designing them as integrated circuits, etc. In addition, the above-mentioned configurations and functions, etc. may be realized in software, by a processor interpreting and executing a program that realizes each function.

[0128] In addition, the signal lines and information lines are those considered necessary for the explanation, and do not necessarily show all control lines and information lines. In addition, the above configurations, functions, processing units, processing procedures, etc. do not necessarily need to be in the same physical location, and for example, some of them may be on a network or in the cloud via communication, etc.

[0129] Also, the motor has been explained as having an inner rotor structure with the rotor placed inside the stator, but of course an outer rotor structure is also acceptable. It can also be a radial gap motor or an axial gap motor. In addition to PMSM, a synchronous motor or SRM with magnets can also be used. [Explanation of symbols]

[0130] 10...control unit, 11...current command value calculation unit, 12, 12a, 12b...voltage command value calculation unit, 13, 13a...coordinate conversion unit, 14...PWM signal generation unit, 15...angular velocity calculation unit, 20...electric motor (PM motor), 21...stator, 22...rotor, 25...winding (coil), 25...shunt resistor, 26...stator core (stator iron core), 27...permanent magnet, 28...winding, 28...fixed child magnetic pole, 30... inverter, 32, 32a, 32b, 32c, 32d, 32e, 32f... switching elements, 34a, 34b, 34c, 34d, 34e, 34f... drive signal, 40, 40a, 40b, 40c, 40e... magnet temperature estimation unit, 41a... d-axis magnetic flux estimation unit, 42a, 42b, 42c, 42d, 42e... transient component calculation unit, 43a... magnet magnetic flux calculation unit, 4b...q-axis magnetic flux command value calculation unit, 45b, 45e...q-axis magnetic flux detection value calculation unit, 50...current detection unit, 60...angle sensor, 70...voltage sensor, 80...d-axis magnetic flux command value calculation unit, 81...q-axis magnetic flux command value calculation unit, 82...d-axis magnetic flux detection value calculation unit, 83...q-axis magnetic flux detection value calculation unit, 84...voltage command value calculation unit, 90...electrical angle, 90d...adder, 91f...subtractor, 92g, 92h, 9 2i, 92j, 92k... multiplier, 98a, 98b... filter circuit (low-pass filter), 100... motor control device, 114a... d-axis current controller, 114b... q-axis current controller, 120... DC voltage source, 123... gate driver circuit, 131... inverter module, 135... shunt resistor, 421c... q-axis inductance calculation unit, PMSM... permanent magnet synchronous motor

Claims

1. A motor control device that drives a motor by an inverter, a transient component calculation unit that calculates a q-axis magnetic flux differential value based on a difference between a q-axis magnetic flux command value and a q-axis magnetic flux detection value, or a difference between a q-axis current command value and a q-axis current detection value; a d-axis magnetic flux estimator that calculates a d-axis magnetic flux estimate based on a q-axis voltage value, a q-axis current, an electrical angular velocity, and the q-axis magnetic flux differential value; a magnet temperature calculation unit that calculates a magnet temperature estimation value based on the d-axis magnetic flux estimation value; A motor control device comprising:

2. 2. The motor control device according to claim 1, the transient component calculation unit calculates the q-axis magnetic flux differential value based on a value obtained by multiplying a difference between the q-axis magnetic flux command value and the q-axis magnetic flux detection value by the inverse of a response time constant of the q-axis magnetic flux detection value to the q-axis magnetic flux command value, or a value obtained by multiplying a difference between the q-axis current command value and the q-axis current detection value by the inverse of a response time constant of the q-axis current detection value to the q-axis current command value.

3. 3. The motor control device according to claim 1, a q-axis magnetic flux command value calculation unit that calculates the q-axis magnetic flux command value based on the d-axis current command value and the q-axis current command value; a q-axis magnetic flux detection value calculation unit that calculates the q-axis magnetic flux detection value based on the d-axis current detection value and the q-axis current detection value; A motor control device comprising:

4. A motor control device that drives a motor by an inverter, a transient component calculation unit that calculates a q-axis magnetic flux differential value in consideration of magnetic saturation of the motor based on a d-axis current detection value, a q-axis current detection value, a q-axis current command value, or a q-axis magnetic flux detection value; a d-axis magnetic flux estimator that calculates a d-axis magnetic flux estimate based on a q-axis voltage value, a q-axis current, an electrical angular velocity, and the q-axis magnetic flux differential value; a magnet temperature calculation unit that calculates a magnet temperature estimation value based on the d-axis magnetic flux estimation value; A motor control device comprising:

5. 5. The motor control device according to claim 4, The transient component calculation unit is a calculation means for calculating a q-axis current differential value from a difference between the q-axis current command value and the q-axis current detection value, or a q-axis current differentiator for calculating the q-axis current differential value by differentiating the q-axis current detection value; a q-axis inductance calculation unit that calculates a q-axis inductance based on the d-axis current detection value and the q-axis current detection value, A motor control device comprising: a motor control unit that calculates the q-axis magnetic flux differential value by the product of the q-axis current differential value and the q-axis inductance; or a motor control unit that calculates the q-axis magnetic flux differential value by a q-axis magnetic flux differentiator that differentiates the q-axis magnetic flux detection value.

6. 6. The motor control device according to claim 4, a q-axis magnetic flux detection value calculation unit that calculates the q-axis magnetic flux detection value based on the d-axis current detection value and the q-axis current detection value.

7. A method for controlling a motor driven by an inverter, comprising the steps of: a transient component calculation unit that calculates a q-axis magnetic flux differential value based on a difference between a q-axis magnetic flux command value and a q-axis magnetic flux detection value, or a difference between a q-axis current command value and a q-axis current detection value; calculating a d-axis magnetic flux estimate based on a q-axis voltage value, a q-axis current, an electrical angular velocity, and the q-axis magnetic flux differential value; calculating a magnet temperature estimate based on the d-axis magnetic flux estimate; A control method comprising the steps of:

8. A method for controlling a motor driven by an inverter, comprising the steps of: calculating a q-axis magnetic flux differential value in consideration of magnetic saturation of the motor based on a d-axis current detection value, a q-axis current detection value, a q-axis current command value, or a q-axis magnetic flux detection value; calculating a d-axis magnetic flux estimate based on a q-axis voltage value, a q-axis current, an electrical angular velocity, and the q-axis magnetic flux differential value; calculating a magnet temperature estimate based on the d-axis magnetic flux estimate; A control method comprising the steps of:

Images