Motor control device and electric vehicle system

Abstract

To provide a motor control device capable of improving accuracy and reliability of magnetic flux estimation.SOLUTION: A motor control device has a voltage command preparation unit (41) generating a voltage command for controlling output voltage of a power conversion device according to a speed command or a torque command of a motor in which a rotor has a permanent magnet, a dead time compensation unit (42) performing a dead time compensation for the voltage command, and a magnetic flux estimation unit (50) estimating a magnetic flux of the permanent magnet. The magnetic flux estimation unit estimates the magnetic flux of the permanent magnet based on the voltage command, and a voltage drop occurring in the motor and the power conversion device, and between the motor and the power conversion device. The voltage drop includes a first voltage drop component due to resistance components, a second voltage drop component occurring due to the dead time compensation, and a third voltage drop component that is the voltage drop from which the first voltage drop component and the second voltage drop component are excluded.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a motor control device and an electric vehicle system using the same. [Background technology]

[0002] Permanent magnet synchronous motors are widely used in fields such as electric vehicles because their field is provided by permanent magnets, which is advantageous for achieving high efficiency. In permanent magnet synchronous motors, fluctuations in the magnetic flux of the permanent magnet due to factors such as temperature can cause fluctuations in motor characteristics such as torque characteristics. For this reason, in some applications, the magnetic flux of the permanent magnet is estimated, and the permanent magnet synchronous motor is controlled based on the estimated magnetic flux.

[0003] The techniques described in Patent Documents 1 and 2 are known as conventional techniques for estimating the amount of magnetic flux of a permanent magnet synchronous motor.

[0004] In the technology described in Patent Document 1, the estimated magnetic flux change amount Δφest from a reference state, for example, a reference temperature state, is calculated based on the d-axis voltage Vd_std and the q-axis voltage Vq_std in the reference state, and the d-axis corrected voltage command value Vd ** and the voltage command value Vq after q-axis correction ** , and the electrical angular velocity ω (Δφest = ((Vq ** / Vd ** )×Vd_std-Vq_std) / ω). Vd ** and Vd ** are the d-axis voltage command value Vd * and the q-axis voltage command value Vq * Vd * and Vq * is corrected according to the dead time Tdead of the switching elements in the inverter and the DC voltage drop of the switching elements. * and Vq * The correction amount according to Tdead is calculated based on the inverter's DC input voltage Vdc, switching frequency Fsw, Tdead, and current phase βd based on the d-axis (see paragraph

[0054] ).* and Vq * The amount of correction according to the DC voltage drop of the switching element is calculated using a voltage drop correction map that uses current as an argument.

[0005] In the technology described in Patent Document 2, a magnetic flux estimation value calculated based on a q-axis voltage command value, a d-axis voltage command value, a q-axis current, a d-axis current, and an angular velocity ω is corrected by an error correction value calculated using a plurality of maps using, as arguments, a plurality of parameters related to the operating state of the permanent magnet synchronous motor, namely, the angular velocity, the torque (or current), the temperatures of each part (sensor temperature, motor temperature, inverter temperature), and the DC voltage of the inverter. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2019-129572 [Patent Document 2] Japanese Patent Application Publication No. 2019-129573 Summary of the Invention [Problem to be solved by the invention]

[0007] In Patent Document 1, in the calculation of the magnetic flux fluctuation amount estimated value Δφest, the d-axis corrected voltage command value Vd ** q-axis corrected voltage command value Vq ** Ratio of (Vq ** / Vd ** ) is used, so Vd ** When is small, the estimated magnetic flux fluctuation amount Δφest itself increases, which causes a problem in the reliability of the estimated value.

[0008] In Patent Document 2, the q-axis voltage command value and the d-axis voltage command value used in calculating the magnetic flux estimation value are not corrected, which limits the improvement in the accuracy of the magnetic flux estimation value.

[0009] Therefore, the present invention provides a motor control device that can improve the accuracy and reliability of magnetic flux estimation, and an electric vehicle system that uses this motor control device. [Means for solving the problem]

[0010] In order to solve the above problems, a motor control device according to the present invention includes a voltage command creation unit that generates a voltage command for controlling the output voltage of a power conversion device to the motor in accordance with a speed command or a torque command of the motor, the motor having a rotor with a permanent magnet; a dead time compensation unit that performs dead time compensation on the voltage command; and a magnetic flux estimation unit that estimates the magnetic flux of the permanent magnet, wherein the magnetic flux estimation unit estimates the magnetic flux of the permanent magnet based on the voltage command and voltage drops that occur between the motor and the power conversion device, and between the motor and the power conversion device, and the voltage drops include a first voltage drop component due to resistance components between the motor and the power conversion device, and between the motor and the power conversion device, a second voltage drop component that occurs due to dead time compensation, and a third voltage drop component obtained by subtracting the first voltage drop component and the second voltage drop component from the voltage drop.

[0011] In order to solve the above problems, an electric vehicle system according to the present invention comprises wheels, a motor that drives the wheels, a power conversion device that supplies power to the motor, and a control device that controls the power conversion device, wherein the control device is the motor control device according to the present invention. [Effects of the Invention]

[0012] According to the present invention, the accuracy and reliability of magnetic flux estimation can be improved.

[0013] Problems, configurations, and effects other than those described above will become apparent from the following description of the embodiments. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a functional block diagram showing a schematic configuration of a motor drive system according to a first embodiment. [Figure 2]1 is a cross-sectional view showing the structure of a permanent magnet synchronous motor 10, taken along a direction perpendicular to the rotation axis. [Figure 3] 1 is a diagram showing the relationship between the dq axes and three-phase windings 15 in a stator 11 of a permanent magnet synchronous motor 10. FIG. [Figure 4] 1 is a circuit diagram showing a configuration of a power conversion device 20 (FIG. 1). [Figure 5] FIG. 2 is a waveform diagram showing an example of drive signals (GXP, GXN) (X: any one of U, V, and W). [Figure 6] FIG. 2 is a functional block diagram showing the configuration of a voltage command generating unit 41. [Figure 7] 2 is a functional block diagram showing the configuration of a magnetic flux estimation unit 50 (FIG. 1) in the first embodiment. [Figure 8] 10 is a calculation example of a q-axis voltage drop Vdrop_q′ shown as a contour map on the Id-Iq plane. [Figure 9] 9 is a graph showing the relationship between Iq and Vdrop_q shown in FIG. 8, with Id as a parameter. [Figure 10] 10 is a calculation example of a second q-axis voltage drop Vdrop_q′ expressed as a contour map on the Id-Iq plane. [Figure 11] 11 is a graph showing the relationship between Iq and Vdrop_q′ shown in FIG. 10 using Id as a parameter. [Figure 12] 10 is a calculation example of a third q-axis voltage drop Vdrop_q″ expressed as a contour map on the Id-Iq plane. [Figure 13] 4 is a functional block diagram showing the configuration of a calculation unit for a q-axis voltage drop Vdrop_q_est in the motor control device 40. FIG. [Figure 14] FIG. 10 is a functional block diagram showing a schematic configuration of a motor drive system according to a second embodiment. [Figure 15] 15 is a functional block diagram showing an example of the configuration of a command value corrector 48 (FIG. 14). FIG. [Figure 16] FIG. 10 is a functional block diagram showing a schematic configuration of a motor control device in a motor drive system according to a third embodiment. [Figure 17]FIG. 10 is a functional block diagram showing the configuration of an electric vehicle system 300 according to a fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, embodiments of the present invention will be described with reference to the following Examples 1 to 4 with reference to the drawings.

[0016] In each figure, the same reference numerals indicate the same components or components with similar functions. [Example]

[0017] FIG. 1 is a functional block diagram showing a schematic configuration of a motor drive system according to a first embodiment of the present invention.

[0018] The motor drive system 100 includes a permanent magnet synchronous motor 10, a power conversion device 20, a current sensor 30, and a motor control device 40. Although not shown, a mechanical load is connected to the permanent magnet synchronous motor 10 via a transmission mechanism that mechanically or magnetically transmits the mechanical output of the permanent magnet synchronous motor 10.

[0019] The motor control device 40 controls the rotation speed or torque of the permanent magnet synchronous motor 10 to a desired value by controlling the power conversion device 20. In the first embodiment, the motor control device 40 also has a function of estimating the magnetic flux and temperature of the permanent magnets provided in the permanent magnet synchronous motor 10, as will be described later.

[0020] Each component of the motor drive system shown in FIG. 1 will now be described.

[0021] FIG. 2 is a cross-sectional view showing the structure of permanent magnet synchronous motor 10, taken along a direction perpendicular to the rotation axis.

[0022] The permanent magnet synchronous motor 10 is composed of a stator 11 and a rotor 12 that face each other via an air gap. The stator 11 has multiple stator poles 18, each of which has windings 15 wound around a stator core 16 made of a magnetic material. The rotor 12 has a rotor core 13 made of a magnetic material and a permanent magnet 17 located within the rotor core 13.

[0023] In this embodiment, as shown in FIG. 2, the number of stator poles 18 (= the number of slots) is six, and the number of magnetic poles of the rotor 12 is two. Note that the number of magnetic poles of the stator 11 and the rotor 12 is not limited to the number shown in FIG. 2 and can be set arbitrarily depending on the desired motor characteristics. Furthermore, the multiple windings may be connected in either parallel or series. In this embodiment, the windings 15 of two opposing stator poles 18 on the stator 11 are connected in series to form one phase of winding. Therefore, the stator 11 has three phases of windings (U, V, W).

[0024] When a current flows through the windings 15, the stator magnetic poles 18 generate magnetic poles of either north or south polarity, and the polarity can be changed depending on the direction of the current in the windings 15. In this embodiment, when a positive DC current flows through the windings 15, the stator magnetic poles 18 become south poles, and the rotation angle of the rotor 12 when the north pole of the permanent magnet 17 in the rotor 12 is attracted to this south pole is defined as zero degrees. Note that hereinafter, the rotation angle of the rotor 12 will be referred to as the "rotor position."

[0025] When there are multiple windings 15, the position of any one of the windings is taken as the reference position. In this embodiment, the position of the winding 15 (U-phase winding) located on the right side in Figure 2 is taken as the reference position. Furthermore, counterclockwise rotation of the rotor 12 is referred to as forward rotation, and clockwise rotation is referred to as reverse rotation.

[0026] In this embodiment, the rotor position is detected by a rotation detector such as a resolver or an encoder, and is used for control processing in the motor control device 40. Note that the rotor position may also be estimated based on the motor current flowing through the permanent magnet synchronous motor 10 or the voltage applied to the permanent magnet synchronous motor 10, without using a rotation detector, by applying so-called position sensorless control.

[0027] In this embodiment, as shown in FIG. 2, an embedded magnet type permanent magnet synchronous motor 10 is used, but this is not limiting, and a motor having a rotor equipped with a permanent magnet whose magnetic flux changes depending on the rotor temperature, such as a surface magnet type permanent magnet synchronous motor, may also be used.

[0028] So-called vector control is applied to the motor control device 40. Therefore, the relationship between the permanent magnet synchronous motor 10 and the rotating coordinate axes (dq axes) used in the vector control will be explained.

[0029] FIG. 3 is a diagram showing the relationship between the dq axes and three-phase (U, V, W) windings 15 in the stator 11 of the permanent magnet synchronous motor 10. As shown in FIG.

[0030] 3, the three-phase windings (U, V, W) are arranged with a phase difference of 120 electrical degrees. The direction of the main magnetic flux of permanent magnet 17 in rotor 12 is defined as the d-axis, and the direction 90 electrical degrees ahead of the d-axis in the direction of rotation is defined as the q-axis.

[0031] The dq axes are coordinate axes in a rotating coordinate system, i.e., coordinate axes set on the rotor 12, and rotate together with the rotor 12. Therefore, the rotation angle of the d axis is equal to the rotor position (θd). As described above, in this embodiment, the position of the U-phase winding is the reference position, and therefore, as shown in FIG. 3, θd is expressed as an angle with the counterclockwise rotation direction from the position of the U-phase winding being positive.

[0032] The direction of the d-axis is also the direction toward the position of the winding 15 at the reference position when the magnetic flux of the permanent magnet 17 that links with the U-phase winding in this embodiment is at its maximum when the rotor 12 is rotated. Therefore, in Figure 3, when θd = 0, the magnetic flux of the permanent magnet 17 that links with the U-phase winding is at its maximum.

[0033] Fig. 4 is a circuit diagram showing the configuration of the power conversion device 20 (Fig. 1). Fig. 4 also shows the permanent magnet synchronous motor 10 and the current sensor 30 (Fig. 1).

[0034] 4, power conversion device 20 has DC voltage source 120, main circuit 131 configured with a three-phase full-bridge circuit of semiconductor switching elements 22a to 22f, and gate drive circuit 123. Shunt resistor 135 is connected between DC voltage source 120 and main circuit 131. This prevents excessive current from flowing through main circuit 131.

[0035] A battery, an AC / DC converter (including a rectifier), a DC / DC converter, or the like is used as the DC voltage source 120. In this embodiment, IGBTs are used as the semiconductor switching elements 22a to 22f, but this is not limiting and MOSFETs or the like may also be used. In this embodiment, the main circuit 131 is configured by an inverter module.

[0036] In the main circuit 131, a free wheel diode is connected in parallel to each of the semiconductor switching elements 22a to 22f, and each parallel connection constitutes an arm. Two arms are connected in series to form upper and lower arms for one phase. In this embodiment, as shown in FIG. 4, the upper and lower arms of the U phase are formed by switching elements 32a and 32b, the V phase by switching elements 32c and 32d, and the W phase by switching elements 32e and 32f. The connection points of the upper and lower arms of each phase are connected to the permanent magnet synchronous motor 10.

[0037] The gate drive circuit 123 receives an on / off control signal S consisting of a PWM pulse signal output by the PWM signal generator 43 (FIG. 1).UP ~S WN Based on this, the drive signal G UP ~G WN and outputs it to the control terminals (gate terminals in this embodiment) of the semiconductor switching elements 22a to 22f. UP ~G WN It is driven on and off by

[0038] Main circuit 131 converts DC voltage Edc of DC voltage source 120 into a three-phase AC voltage by turning semiconductor switching elements 22a to 22f on and off, and outputs this three-phase AC voltage to the three-phase AC terminals of permanent magnet synchronous motor 10.

[0039] Figure 5 shows the drive signal (G XP ,G XN 5 is a waveform diagram showing an example of the triangular wave carrier signal S ) (X: one of U, V, and W). C and X-phase voltage command V X * An example of this is also provided.

[0040] As shown in FIG. 5, the PWM signal generator 43 (FIG. 1) generates a triangular wave carrier signal S C and X-phase voltage command V X * , an on / off control signal S consisting of a PWM pulse signal (not shown in FIG. 5) is generated. XP ,S XN The gate drive circuit 123 generates an OFF control signal S XP ,S XN In response to the XP ,S XN and a drive signal G having a voltage value sufficient to drive the semiconductor switching element. XP ,G XN Generate.

[0041] In the power conversion device 20, the semiconductor switching elements are switched at a frequency that is sufficiently higher than the frequency of the AC voltage output to the permanent magnet synchronous motor 10. That is, the triangular wave carrier signal S C The frequency of the X-phase voltage command V X * Therefore, the voltage of each phase output from the main circuit 131 of the power conversion device 20 is set to be sufficiently higher than the frequency of the drive signal G XP ,G XN However, when averaged over time, it becomes a sine wave voltage whose voltage value changes in response to changes in the duty factor.

[0042] By changing the magnitude of the duty factor and the period of change in magnitude, i.e., the X-phase voltage command V X * By changing the magnitude and frequency of the three-phase AC voltage, it is possible to control the magnitude (amplitude) and frequency of the three-phase AC voltage output by the power conversion device 20. This enables variable speed driving and torque control of the permanent magnet synchronous motor 10.

[0043] The current sensor 30 detects three-phase motor currents flowing from the power conversion device 20 to the permanent magnet synchronous motor 10. In this embodiment, the current sensor 30 detects a U-phase motor current I U and W-phase motor current I W Detects the V-phase motor current (I V ") is the detected U-phase motor current I U and W-phase motor current I W is calculated in the motor control device 40 based on V =-I U -I W ) As the current sensor 30, for example, a current transformer (CT) is used.

[0044] A Hall CT or a shunt resistor may be used as the current sensor 30. When a shunt resistor is used, a so-called one-shunt system or a three-shunt system is used. In the one-shunt system, the DC input current to the main circuit 131 (FIG. 4), i.e., the DC bus current, is detected by one shunt resistor (e.g., shunt resistor 135 in FIG. 4), and the three-phase motor current is detected based on the detected value of the DC bus current. In the three-shunt system, a shunt resistor is provided in each of the three-phase lower arms, and the three-phase motor current is detected based on the current values ​​detected by these three shunt resistors.

[0045] Next, the motor control device 40 (FIG. 1) will be described.

[0046] The motor control device 40 controls at least one of the speed and torque of the permanent magnet synchronous motor 10 by controlling the switching operation of the power conversion device 20. In this case, the motor control device 40 controls the speed command ω r * or torque command Trq * and the motor current detected by the current sensor 30, a three-phase voltage command V U * ,V V * ,V W * The speed command ω r * or torque command Trq * may be set in the motor control device 40, or may be provided to the motor control device 40 from another control system such as a higher-level control system not shown in FIG.

[0047] Furthermore, the motor control device 40 generates a three-phase voltage command V U * ,V V * ,V W * The on / off control signal S consists of PWM pulses according to UP ~S WN The motor control device 40 generates the on-off control signal SUP ~S WN The switching operation of the power conversion device 20 is controlled by the above.

[0048] As described above, so-called vector control is applied to the motor control device 40. Therefore, the voltage command generation unit 41 (FIG. 1) generates a voltage command value by performing arithmetic processing in a rotating coordinate system.

[0049] FIG. 6 is a functional block diagram showing the configuration of the voltage command generating unit 41. As shown in FIG.

[0050] The voltage command generator 41 generates a speed command or a torque command (ω r * ,Trq * ) the first d-axis current command I d * and the first q-axis current command I q * and the d-axis detected current I dc and q-axis detected current I qc and inverter frequency command ω1 (ωr instead of ω1) * (or it can be used) and use equations (1) and (2) to obtain the d-axis voltage command V d * and q-axis voltage command V q * Generate I dc and I qc is calculated by converting the three-phase motor current detected by the current sensor 30 from the stationary coordinate system to the rotating coordinate system.

[0051]

number

[0052]

number

[0053] In equations (1) and (2), R is the winding resistance per phase of the permanent magnet synchronous motor 10, Ld is the d-axis inductance, L q is the q-axis inductance, and Ke is the induced voltage constant.

[0054] I d ** and I q ** is the motor current I d * and I q * are generated by a current controller that uses PI control to make the current flow in accordance with the second d-axis current command and the second q-axis current command, respectively.

[0055] I d ** In the d-axis current controller 114a that generates the first d-axis current command I d * and d-axis detected current I dc Difference with (I d * -I dc ) is calculated, and the proportional gain (K p_d ) is multiplied by the proportionality regulator 92d. i_d ) and integrated by the integrator 94c. p_d The difference calculation value multiplied by and the integral gain K i_d The integral value multiplied by I is added by an adder 90b, and I d ** is calculated.

[0056] I q ** In the q-axis current controller 114b that generates the first q-axis current command I q * and the q-axis detected current I qc Difference with (I q * -I qc ) is calculated, and the proportional gain (K p_q) is multiplied by the proportionality regulator 92f. i_q ) and integrated by the integrator 94d. p_q The difference calculation value multiplied by and the integral gain K i_q The integral value multiplied by I is added by an adder 90c, and I q ** is calculated.

[0057] Id ** is multiplied by R by the multiplier 92g, and becomes "R × I" on the right side of the equation (1). d ** " is calculated. Iq ** is multiplied by R by the multiplier 92i, and becomes "R × I" on the right side of the equation (2). q ** " is calculated.

[0058] I q ** is filtered by the low-pass filter 98a to obtain I q ** _fil Furthermore, I q ** _fil is multiplied by multiplier 92h. q and ω1 are multiplied, and the right-hand side of equation (1) becomes "ω1 × L q ×I q ** _fil The adder-subtractor 91f calculates "R×I" calculated by the multiplier 92g. d ** " is calculated by multiplier 92h, and "ω1 × L q ×I q ** _fil " is subtracted. This results in V d * is generated.

[0059] I d ** is filtered by the low-pass filter 98b to obtain I d** _fil Furthermore, I d ** _fil is multiplied by multiplier 92j. d and ω1 are multiplied, and the right-hand side of equation (2) becomes "ω1 × L d ×I d ** _fil The multiplier 92k multiplies ω1 by Ke to calculate "ω1 × Ke" in equation (2). The adder 90d multiplies "R × I" calculated by the multiplier 92i. q ** " and "ω1×L" calculated by multiplier 92j. d ×I d ** _fil " and "ω1 × Ke" calculated by the multiplier 92k are added together. q * is generated.

[0060] As described above, in the voltage command generating unit 41, the d-axis current controller 114a and the q-axis current controller 114b are cascade-connected to the voltage calculation unit based on the equations (1) and (2). The voltage calculation unit also includes a time constant (T q (=L q / R),T d (=L d Low-pass filters 98a and 98b having a first-order delay with a lag time of 1 / R are applied. This makes it possible to achieve stable vector control even when there are restrictions on the calculation period.

[0061] The magnetic flux estimation function provided in the motor control device 40 in the first embodiment will be described below.

[0062] FIG. 7 is a functional block diagram showing the configuration of the magnetic flux estimation unit 50 (FIG. 1) in the first embodiment.

[0063] 7 also shows, in addition to the magnetic flux estimation unit 50, a magnetic flux table 51, a stray voltage table 52, a dead time compensation error calculation unit 53, and a winding resistance estimation unit 54, which are involved in magnetic flux estimation.

[0064] In this embodiment, when a three-phase AC voltage is output from the power conversion device 20 to the permanent magnet synchronous motor 10, the q-axis voltage command Vq * , the rotational angular velocity ω of the permanent magnet synchronous motor 10 e (electrical angle), d-axis current I d and q-axis current I q , the d-axis interlinkage magnetic flux Ψ representing the magnet magnetic flux based on the DC voltage Edc of the DC voltage source 120 (FIG. 2) and the winding temperature Temp_w. d In addition, the magnet temperature Temp_m is estimated.

[0065] The q-axis voltage equation in the steady state of the permanent magnet synchronous motor 10 is the differential term (sL q I q ** ) can be expressed by equations (3) and (4). Note that Ψ in equation (4) d0 is the d-axis interlinkage magnetic flux component due to the permanent magnet only.

[0066]

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[0067]

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[0068] The q-axis voltage drop V in equation (3) drop_q is the speed electromotive force (induced voltage: ω e ×Ψ d ) and the q-axis voltage command value V q * Difference with (V q * -ω e ×Ψ d) is the total voltage drop on the q axis, including the voltage drop due to the winding resistance R, the voltage drop in the switching elements (22a to 22f in Figure 4), the error voltage due to the dead time, and the error voltage due to the PWM method. Based on equation (3), V drop_q Considering these multiple voltage components that make up V drop_q By calculating d can be estimated.

[0069] First, the d-axis current I d and q-axis current I q on the lattice points ((I d ,I q )) and (I d ,I q ) versus d-axis voltage and q-axis voltage (V d ,V q At this time, the magnet temperature Temp_m is measured at a constant value (Temp_m _calib ), for example, to a preset standard temperature.

[0070] The rotational angular velocity (electrical angle) of the permanent magnet synchronous motor 10 is ω e1 and ω e2 The q-axis voltage command value when q1 * and V q2 * Then, V q1 * and V q2 * can be expressed by equations (5) and (6) based on equation (3). e2 >ω e1 Let's say.

[0071]

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[0072]

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[0073] Here, the d-axis interlinkage magnetic flux Ψ d and q-axis voltage drop V drop_q is said to be independent of the rotation speed.

[0074] From equations (5) and (6), the d-axis interlinkage magnetic flux Ψ d and q-axis voltage drop V drop_q are expressed by equations (7) and (8), respectively.

[0075]

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[0076]

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[0077] The above measurement data ((I d ,I q ) for (V d ,V q )) and from equations (7) and (8), (I d ,I q ) as argument Ψ d and V drop_q Each table data is calculated. d and V drop_q The table data of the magnetic flux table 51(Ψ d_calib_table ) and q-axis voltage drop compatibility table (V drop_q_calib_table ) and stored in the motor control device 40.

[0078] q-axis voltage drop V drop_q contains voltage drop components caused by multiple factors. Based on the study by the inventor, in this embodiment, in order to estimate the magnetic flux with high accuracy, the q-axis voltage drop component is corrected for the following three factors. The three factors are the dead time error time, the resistance component including the winding resistance, and the V obtained from the q-axis voltage drop compatibility table. drop_q is the remaining voltage drop component (stray voltage) obtained by subtracting the voltage drop component caused by the dead time error time and the resistance component from the above.

[0079] Considering the above three factors, V drop_q is expressed by equation (9).

[0080]

number

[0081] The first term on the right side of equation (9) (RI q ) is the voltage drop component due to the resistance component R, and the d-axis current I d In equation (9), R is the sum of the winding resistance of the permanent magnet synchronous motor 10, the resistance components of the semiconductor switching elements (22a to 22: FIG. 4), and the resistance components from the power conversion device 20 to the permanent magnet synchronous motor 10, such as the wiring cables (hereinafter referred to as "total resistance value"). The second term (V dead_q ) is the voltage drop component that occurs due to dead time compensation. err_q ) is called the stray error voltage, and includes nonlinear components of the voltage drop of the semiconductor switching elements, nonlinear components caused by the switching of the semiconductor switching elements, and components caused by the leakage flux and structure of the permanent magnet synchronous motor 10, and is a value specific to the combination of the power conversion device 20 and the permanent magnet synchronous motor 10.

[0082] Below, V dead_q First, a brief explanation of dead time will be given.

[0083] Although not shown or described in FIG. 5, the drive signal G XP and a drive signal G that drives the semiconductor switching element of the X-phase lower arm. XN In order to prevent short-circuiting between the upper and lower arms, a period during which the semiconductor switching elements of both arms are turned off, that is, a so-called dead time, is set in the upper and lower arms.

[0084] In this embodiment, the on / off control signal S UP ~S WNThe dead time is set to

[0085] When a dead time is set, an error (dead time error voltage) occurs between the voltage (voltage command) to be applied to the permanent magnet synchronous motor 10 and the voltage actually applied to the permanent magnet synchronous motor 10. This causes waveform distortion of the motor current. Therefore, in this embodiment, the dead time compensator 42 (FIG. 1) adjusts the dead time error voltage by adjusting the dead time error voltage. d * and V q * Three-phase AC voltage command V U * ,V V * ,V W * Furthermore, in order to reduce waveform distortion of the motor current due to dead time, V U * ,V V * ,V W * The dead time error voltage is compensated for.

[0086] There are various known techniques for dead time compensation to compensate for dead time error voltages. For example, the polarity of the three-phase current is determined from the current command on the dq axis, and the three-phase AC voltage command is corrected based on the polarity of the three-phase current.

[0087] The dead time compensator 42 of this embodiment calculates the dead time error voltage using a predetermined formula based on the DC power supply voltage, switching frequency, dead time, and current phase of the power conversion device 20.

[0088] The dead time compensation error calculation unit 53 (FIG. 1) in this embodiment calculates a voltage drop component (hereinafter referred to as a dead time compensation error voltage) that occurs due to dead time compensation.

[0089] The dead time compensation error calculation unit 53 calculates the dead time compensation error voltage V dead_q is calculated using equations (10) and (11).

[0090]

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[0091]

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[0092] In equations (10) and (11), Edc is the DC voltage of the DC voltage source 120 (FIG. 2), T sw is the switching period, β is the current phase angle based on the d axis, T dead_real is the actual dead time, T dead_cmp is the dead time compensation time (corresponding to the dead time (set value)).

[0093] Actual dead time T dead_real and the dead time compensation time T dead_cmp are often set to the same value. However, they may also be set to different values. For example, when the motor inductance is small, it may be desirable to suppress distortion in the motor current. In such cases, the dead time compensation time is set to a value that minimizes distortion in the motor current. Since current distortion near the current zero crossing tends to increase when the dead time compensation amount is increased, the dead time compensation time may be set to a small value that differs from the actual dead time time. In such cases, the dead time compensation error voltage V shown in equations (10) and (11) dead_q The dead time compensation error voltage V dead_q means the error voltage due to overcompensation or undercompensation when dead time compensation is performed.

[0094] In this embodiment, even when the actual dead time set by the PWM signal generating unit 43 or the gate driving circuit 123 differs from the dead time compensation time compensated for by the dead time compensating unit 42, magnetic flux estimation can be performed with high accuracy.

[0095] Here, the q-axis voltage drop V drop_q A calculation example of will be described with reference to FIGS. 8 and 9.

[0096] Figure 8 shows the I d -I q q-axis voltage drop V shown as an isoline plot on a plane drop_q In addition, Fig. 9 shows an example of the calculation of I q and V drop_q The relationship between d is a graph showing the parameter.

[0097] According to Figure 8, q In contrast to I d As becomes larger in the negative direction, V drop_q It can be seen that the absolute value of I tends to decrease. d As becomes negative, I q is positive, V drop_q decreases, I q When V is negative drop_q In addition, Figure 9 also shows that I d Depending on the value of I q V against drop_q It can be seen that the changes are different.

[0098] Based on equations (10) and (11), I q V against drop_q The reason for the difference in the change in the dead-time compensation error voltage V dead_q On the other hand, if the actual dead time and the dead time compensation time are the same, the q-axis voltage drop V drop_q In equation (9), the voltage drop component due to the resistance component R in the first term on the right side is the dominant component. In this case, I d Without relying on q By V drop_q The value of is determined.

[0099] As mentioned above, the q-axis voltage drop V is calculated in advance and stored as table data. drop_q To calculate the dead time error, the q-axis voltage drop V is calculated as shown in equation (12). drop_q to the dead time compensation error voltage V dead_q The second q-axis voltage drop V drop_q' is defined.

[0100]

number

[0101] V drop_q In order to calculate the dead time error time when calculating the table data, the dead time compensation error time T dead_calib The second q-axis voltage drop V drop_q 'I d The dead time compensation error time T that has the smallest dependency dead_calib In other words, I shown in Figure 9 d The graph with parameters T is the state where multiple graphs overlap most. dead_calib At this time, various known optimization calculations can be used, but in this embodiment, the dead time compensation error time T dead_calib As shown in the following equations (13) and (14), V drop_q The q-axis voltage drop V when calculating the table data drop_q Calculate the population mean μ and variance V.

[0102]

number

[0103]

number

[0104] N in Equations (13) and (14) Id There is I q I in Data d The variance is shown in Figure 9. q -V drop_q V in the plane drop_q This corresponds to the variation in

[0105] Furthermore, each I qSecond q-axis voltage drop V at the data point drop_q The sum S of the variances of ' is calculated using equation (15).

[0106]

number

[0107] When the sum S expressed by equation (15) is minimized, the second q-axis voltage drop V drop_q 'I d Assuming that the dependency (variation) on dead_calib Ask for.

[0108] The q-axis voltage drop V shown in Figs. 8 and 9 drop_q In the measurement example, the dead time compensation error time T dead_calib (for example, every 0.1 μs) and calculate the dead time compensation error time T dead_calib The second q-axis voltage drop V drop_q ' is shown in Figures 10 and 11.

[0109] Figure 10 shows the I d -I q The second q-axis voltage drop V is plotted as an isoline on the plane. drop_q 11 is a calculation example of I' shown in FIG. q and V drop_q 'Relationship, I d is a graph showing the parameter.

[0110] Comparing Figure 10 with Figure 8, the second q-axis voltage drop Vd rop_q The contour line of ' is parallel to the d axis. q The second q-axis voltage drop V drop_q 'I d In addition, comparing Figure 11 with Figure 9, I d With parameters, I q V against drop_q Several graphs showing the change in V are overlaid. drop_qDead time error time T when calculating table data dead_calib can be calculated.

[0111] Next, the voltage drop component due to the resistance component will be described.

[0112] In this embodiment, the resistance component R in the above-mentioned equation (9) is calculated from the slope of the graph in FIG. q V for each data point drop_q Calculate the average value of ', perform a linear approximation using the least squares method to find the slope, and V drop_q Total resistance R when calculating table data calib Let's say.

[0113] In addition, the total resistance R calib may be calculated.

[0114] R calib The winding resistance R changes depending on the winding temperature Temp_w. w The resistance components of the switching elements and the wiring cables and other components from the power conversion device 20 to the permanent magnet synchronous motor 10 are included. drop_q The winding temperature when calculating the table data is Temp_w _calib and the winding resistance R w Table data for winding temperature (winding resistance table R w _table) and V drop_q Winding temperature Temp_w when calculating the table data _calib constant resistance component R that does not depend on calib_const is calculated using equation (16).

[0115]

number

[0116] In addition, the winding resistance R w may be calculated using a known formula.

[0117] Next, a voltage drop component other than the dead time error voltage and the voltage drop due to the resistance component, that is, a voltage drop component called a stray voltage, will be described.

[0118] V drop_q The q-axis voltage drop V when calculating the table data drop_q From the dead time compensation error voltage V dead_q and total resistance R calib The remaining voltage drop component excluding the voltage drop component due to the third q-axis voltage drop V drop_q '' is defined in equation (17). Note that V in the first term on the right side of equation (17) drop_q ' is the second q-axis voltage drop (equation (12)) mentioned above.

[0119]

number

[0120] Figure 12 shows the I d -I q The third q-axis voltage drop V is plotted as an isoline on a plane. drop_q '' is a calculation example.

[0121] V drop_q In the calculation of '', V shown in Figure 8 drop_q The calculation example of (I d ,I q ) as argument V drop_q '' table data (V err_q_calib _ table ) is calculated. V drop_q The table data of "" is stored in the motor control device 40 as a stray voltage table 52 (FIGS. 1 and 7).

[0122] As can be seen from Figure 12, V drop_q '' is the q-axis voltage drop V drop_q From the dead time compensation error voltage V dead_q and total resistance R calib Voltage drop component due to (R calib I d) is the remaining voltage drop component excluding the voltage drop component, so it is a very small value.

[0123] According to the inventor's investigation, V drop_q It is difficult to identify specific factors and express them in a calculation formula. drop_q '' is called the stray voltage.

[0124] According to the inventors' investigations, the stray voltage is related to the leakage flux and structure of the permanent magnet synchronous motor 10, and is a value specific to the combination of the power conversion device 20 and the permanent magnet synchronous motor 10. Therefore, the stray voltage can be calculated with high accuracy using the stray voltage table.

[0125] It is preferable to create a stray voltage table for each motor control device, but a stray voltage table may be created for a representative combination of power conversion device 20 and permanent magnet synchronous motor 10 and shared by each motor control device.

[0126] Next, V, which has been calculated and stored under predetermined operating conditions, drop_q is corrected according to the operating conditions (DC voltage Edc, winding temperature, switching frequency, etc.) when the permanent magnet synchronous motor 10 is driven, and the q-axis voltage drop V drop_q_est A method for calculating the above will be described.

[0127] FIG. 13 shows the q-axis voltage drop V in the motor control device 40. drop_q_est FIG. 2 is a functional block diagram showing the configuration of the calculation unit.

[0128] Total resistance R when permanent magnet synchronous motor 10 is driven est is calculated by equation (18).

[0129]

number

[0130] In equation (18), T w_estis the winding temperature (Temp_w in Fig. 13) when the motor is driven (when estimating magnetic flux), and R calib_const is the constant resistance component in equation (16) above. w_table (T w_est ) is the winding resistance R w This is table data for the winding temperatures, and is stored in winding temperature table 541 (FIG. 13).

[0131] Estimated total resistance R est As a result, the dependence of the winding temperature is reflected in the value of the voltage drop due to the resistance component.

[0132] Next, the switching period T sw_est , DC voltage E dc_est and current phase angle β est Using this, the dead time compensation error voltage V dead_q_calib is calculated using equation (19). Current phase angle β est is calculated by the current phase calculator 531 (FIG. 13) as I d ,I q The calculation according to equation (19) corresponds to the operation of the calculation unit 532.

[0133]

number

[0134] In addition, equation (19) is the right side of the above equation (10), T sw , E dc and β est respectively, T sw_est , E dc_est and β est This is equivalent to replacing

[0135] V dead_q_calib As a result, differences in operating conditions when the permanent magnet synchronous motor 10 is driven (when the magnetic flux is estimated) are dynamically reflected in the value of the dead-time error voltage.

[0136] Furthermore, when the permanent magnet synchronous motor 10 is driven (when the magnetic flux is estimated), the d-axis current I d_est and q-axis current I q_est Using the stray voltage table 52 (V err_q_calib_table (I d ,I q )) to calculate the stray error voltage V when the permanent magnet synchronous motor 10 is driven (when the magnetic flux is estimated). err_q_est is calculated using equation (20).

[0137]

number

[0138] The above-mentioned R est ,V dead_q_calib ,V err_q_est Using this, the q-axis voltage drop V when the permanent magnet synchronous motor 10 is driven (when the magnetic flux is estimated) is calculated. drop_q_est is calculated by equation (21).

[0139]

number

[0140] The calculation according to equation (21) corresponds to the operation of the calculation unit 501 (FIG. 13).

[0141] Based on the q-axis voltage drop consisting of a plurality of voltage drop components calculated for each factor as described above, the magnetic flux estimation unit 50 (FIG. 7) performs magnetic flux estimation using equation (22).

[0142]

number

[0143] In equation (22), V q_est * is the q-axis voltage command when the permanent magnet synchronous motor 10 is driven (when the magnetic flux is estimated), and ω e_est is the rotational angular velocity ω when the permanent magnet synchronous motor 10 is driven (when the magnetic flux is estimated). e (electrical angle).

[0144] The calculation according to equation (22) corresponds to the operation of the calculation unit 55 in the magnetic flux estimation unit 50 (FIG. 7).

[0145] Furthermore, the magnetic flux estimation unit 50 calculates I d_est ,I q_est Using the same current condition (I d =I d_est ,I q =I q_est ) in V drop_q Magnetic flux Ψ when calculating table data d_calib is calculated by the formula (23). The right side of the formula (23) is the table data Ψ in the magnetic flux table 51 (FIG. 1) that is stored in advance. d_calib_table (I d ,I q ) in the argument (I d ,I q ) is (I d_est ,I q_est ) data.

[0146]

number

[0147] Furthermore, the magnetic flux estimation unit 50 calculates V drop_q The change in d-axis magnetic flux ΔΨ from the time of calculating the table data d is calculated by the formula (24). The dq-axis currents used for the calculation may be detected currents or current command values.

[0148]

number

[0149] d-axis magnetic flux change ΔΨ d indicates the change in the magnet magnetic flux due to the change in the magnet temperature. d) is almost constant regardless of the magnet temperature, so if we ignore it, as in equation (25), when controlling the normal d-axis current Id to be zero, Ψ d_calib Ψ for d_est The ratio of the d-axis magnetic flux change rate is calculated. As with equation (24), the magnetic flux table 51 (FIGS. 1 and 7) is referenced.

[0150]

number

[0151] The denominator of the fraction on the right side of equation (25) is the d-axis magnetic flux change ΔΨ calculated by equation (24). d is equivalent to

[0152] The calculated d-axis magnetic flux change rate is input to the magnet temperature estimation unit 56 (FIG. 7) and compared with a temperature-no-load induced voltage table stored in advance. In this embodiment, the temperature-no-load induced voltage table is drop_q 1 shows the relationship between the ratio of the no-load induced voltage at the magnet temperature Temp_m to the no-load induced voltage at the standard temperature when the table data was calculated, that is, the no-load induced voltage change rate, and the magnet temperature Temp_m.

[0153] As a result of the comparison, the magnet temperature estimation unit 56 outputs the temperature indicating the no-load induced voltage change rate that coincides with the d-axis magnetic flux change rate calculated by equation (25) as the estimated magnet temperature Temp_m.

[0154] According to the first embodiment described above, the voltage drop components are calculated according to their respective causes, namely, the voltage drop component due to the total resistance component including the resistance of the wiring between the permanent magnet synchronous motor 10 and the power conversion device and the resistance of the semiconductor switching elements, the voltage drop component due to dead time compensation, and the voltage drop component due to stray voltage, and the magnetic flux of the permanent magnet is estimated based on these voltage drop components, i.e., based on the difference between the voltage command value and the sum of these voltage drop components, thereby improving the accuracy of magnetic flux estimation.

[0155] In the first embodiment, the predetermined operating conditions of the permanent magnet synchronous motor 10 (in the first embodiment, ω e1 ,ω e2 ), and the motor current (I d ,I q ) from the voltage command to the q-axis voltage drop V drop_q is calculated and stored in the motor control device 40 as table data with the motor current as an argument. Table data for the total resistance component and stray voltage is calculated based on this table data and the calculated value of the voltage drop component due to dead time compensation. This reduces the amount of table data that needs to be collected in advance by operating the actual machine for magnetic flux estimation. This avoids an increase in the workload of creating table data.

[0156] Furthermore, by storing stray voltage, a voltage drop component that is difficult to express in a calculation formula, as table data in advance, it is possible to ensure the accuracy of calculating the voltage drop component even under driving conditions where the voltage applied to the permanent magnet synchronous motor is small, such as low speed or low torque, thereby improving the accuracy of estimating magnetic flux and magnet temperature.

[0157] In the first embodiment, as shown in FIG. 1 , functional components related to magnetic flux estimation, namely, a magnetic flux estimation unit 50, a magnetic flux table 51, a stray voltage table 52, a dead-time compensation error calculation unit 53, and a winding resistance estimation unit 54, are built into the motor control device 40. However, the present invention is not limited to this configuration, and the magnetic flux estimation device may be configured as a separate device from the motor control device 40. In this case, the voltage command and the detected current value (or the current command value) are input to the magnetic flux estimation device via wired or wireless communication. This allows the motor control device to be retrofitted with a magnetic flux estimation function. Furthermore, the degree of freedom in the placement of the motor control device 40 can be increased.

[0158] As described above, this embodiment includes a voltage command value calculation unit that calculates a voltage command value based on a motor torque command, a dead time compensation unit that performs dead time compensation based on the voltage command value, a dead time compensation error calculation unit that calculates a dead time compensation error based on a motor current detection value and a DC voltage detection value, a winding resistance calculation unit that calculates a winding electrical resistance value based on a winding temperature detection value, and a magnetic flux estimation unit that estimates the magnet magnetic flux from the stray voltage, dead time compensation error, and electrical resistance value obtained from the motor current detection value. This reduces errors in the voltage information itself used when estimating magnetic flux, thereby improving the accuracy of magnetic flux estimation. [Example]

[0159] In the permanent magnets used in permanent magnet synchronous motors, when the temperature of the permanent magnets rises, demagnetization occurs, making it difficult to control the rotation speed and torque. In addition, in order to ensure the torque generated by the permanent magnet synchronous motor, the motor current and the current flowing in the power conversion device may increase.

[0160] Therefore, in the second embodiment, the speed command and torque command are limited based on the estimated magnet magnetic flux and magnet temperature.

[0161] 14 is a functional block diagram showing a schematic configuration of a motor drive system according to a second embodiment of the present invention. The following mainly describes the differences from the first embodiment.

[0162] The motor control device 40a in the second embodiment is r * and torque command Trq * The magnetic flux estimation unit 50 estimates the magnet magnetic flux (d-axis interlinkage magnetic flux Ψ d ) or the magnet temperature Temp_m.

[0163] FIG. 15 is a functional block diagram showing an example of the configuration of the command value corrector 48 (FIG. 14).

[0164] The command value correction unit 48 includes a command value limiting unit 481 and a limit value calculation unit 482.

[0165] The command value limiting unit 481 limits the input speed command ω r * and torque command Trq * to the limit value Lmt when they exceed a predetermined value, and outputs the corrected speed command ω r * and torque command Trq * as such. r ** and torque command Trq ** as the output.

[0166] The limit value calculation unit 482 compares the magnet flux (d-axis linkage flux Ψ d ) estimated by the flux estimation unit 50 or the magnet temperature Temp_m with determination threshold values (Th1, Th2: Th1 < Th2), and sets the limit value Lmt to the command value limiting unit 481 according to the magnitude relationship.

[0167] In the second embodiment, as shown in FIG. 15, when Ψ d or Temp_m exceeds the determination threshold value Th1, the limit value Lmt is decreased linearly or quadratically and output. When Ψ d or Temp_m exceeds the determination threshold value Th2, it is determined that the magnet temperature is too high, and the change rate of decreasing the command limit value is made larger.

[0168] Note that the input to the limit value calculation unit 482 may be the reduction rate of the input Ψ d or Temp_m from a preset reference value.

[0169] According to the above-described second embodiment, demagnetization of the permanent magnet and an increase in the current flowing through the permanent magnet synchronous motor and the power conversion device can be suppressed. Therefore, the reliability of the motor control device and the motor drive system is improved.

[0170] Note that instead of the speed command and the torque command, the current command may be adjusted.

Embodiment

[0171] 16 is a functional block diagram showing a schematic configuration of a motor control device 40b in a motor drive system according to a third embodiment of the present invention. The following mainly describes the differences from the second embodiment.

[0172] In the third embodiment, the motor control device 40b includes a protection signal generating unit 49.

[0173] The protection signal generator 49 generates a protection signal based on the magnet magnetic flux (d-axis interlinkage magnetic flux Ψ d ) or the value of the magnet temperature Temp_m is compared with a predetermined threshold, and Ψ d Alternatively, if it is determined that the value of Temp_m has exceeded or fallen below the threshold value, a protection signal is output to the outside of the motor control device 40b.

[0174] When another control device (not shown) receives the protection signal, it reduces the speed command or torque command of the permanent magnet synchronous motor 10 or stops the permanent magnet synchronous motor 10. This improves the reliability of the motor drive system (100 in FIG. 1).

[0175] The motor control device 40 may have the functions of such other control devices. [Example]

[0176] FIG. 17 is a functional block diagram showing the configuration of an electric vehicle system 300 according to a fourth embodiment of the present invention.

[0177] The motor control device 40 controls the AC power supplied from the power conversion device 20 (inverter) to the permanent magnet synchronous motor 10. A DC voltage source 120 (e.g., a battery) supplies DC power to the power conversion device 20 (inverter). The power conversion device 20 (inverter) is controlled by the motor control device 40 to convert the DC power from the DC voltage source 120 into AC power. Any of the motor control devices according to the first to third embodiments described above is applied as the motor control device 40. Therefore, the motor control device 40 has a function of estimating the magnet flux and magnet temperature of the permanent magnet synchronous motor 10.

[0178] The permanent magnet synchronous motor 10 is mechanically connected to a transmission 301. The transmission 301 is mechanically connected to a drive shaft 305 via a differential gear 303, and supplies mechanical power to wheels 307. As a result, the wheels 307 are driven to rotate.

[0179] It should be noted that permanent magnet synchronous motor 10 may be directly connected to differential gear 303 without going through transmission 301. In the case of an automobile, the front wheels and rear wheels may each be driven by an independent permanent magnet synchronous motor and power conversion device (inverter).

[0180] According to this embodiment, the accuracy of magnetic flux estimation by the motor control device 40 is improved, and therefore the rotation speed or torque of the permanent magnet synchronous motor 10 can be controlled with high accuracy, thereby improving the ride comfort of the electric vehicle system.

[0181] Furthermore, according to this embodiment, since the magnet temperature can be estimated, it is possible to prevent the occurrence of abnormalities in the electric vehicle system 300 due to thermal demagnetization of the permanent magnets of the permanent magnet synchronous motor 10.

[0182] Furthermore, according to this embodiment, the motor control device 40 can estimate the magnet magnetic flux and magnet temperature using information about the electric vehicle system 300. For example, instead of the winding temperature Temp_w (FIG. 7), the ambient temperature near the permanent magnet synchronous motor 10 or the power conversion device 20 (inverter) can be used.

[0183] The present invention is not limited to the above-described embodiments and includes various modifications. For example, the above-described examples have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those having all of the described configurations. Furthermore, it is possible to add, delete, or replace part of the configuration of each embodiment with other configurations.

[0184] For example, some or all of the above-described configurations, functions, processing units, processing procedures, etc. may be realized in hardware, for example, by designing them as integrated circuits, etc. Furthermore, the above-described configurations and functions may be realized in software, by a processor interpreting and executing a program that realizes each function.

[0185] Furthermore, the signal lines and information lines shown are those considered necessary for explanation, and do not necessarily represent all control lines and information lines. Furthermore, the above-mentioned configurations, functions, processing units, processing procedures, etc. do not necessarily need to be located in the same physical location; for example, some may be located on a network or in the cloud via communication, etc.

[0186] Furthermore, the permanent magnet synchronous motor may be either an inner rotor type (FIG. 2) or an outer rotor type, and may be either a radial gap type or an axial gap type. [Explanation of symbols]

[0187] 10...Permanent magnet synchronous motor 11...Stator 12...Rotor 13...Rotor core 15...winding 16... Stator core 17...Permanent magnet 18...Stator magnetic pole 20...Power conversion device 22a, 22b, 22c, 22d, 22e, 22f...semiconductor switching elements 30...Current sensor 40, 40a, 40b...Motor control device 41...Voltage command creation unit 42...Dead time compensation section 43...PWM signal creation section 48...Command value correction unit 49...Protection signal generation section 50...Magnetic flux estimation unit 51...Magnetic flux table 52... Stray voltage table 53...Dead time compensation error calculation section 54...Winding resistance estimation section 55...Arithmetic section 56...Magnet temperature estimation section 90b, 90c, 90d...adder 91d, 91e, 91f...Adder / Subtractor 92c, 92d, 92e, 92f…Proportionalizer 92g, 92h, 92i, 92j, 92k... multiplier 94c,94d…integrator 98a, 98b...Low-pass filters 100...Motor drive system 114a...d-axis current controller 114b...q-axis current controller 120...DC voltage source 123...Gate drive circuit 131…Main circuit 135...Shunt resistor 300...Electric vehicle system 301...Transmission 303...Differential gear 305...Drive shaft 307...Wheel 481...Command value limiting section 482...Limit value calculation unit 501...Arithmetic section 531...Current phase calculator 532...Arithmetic section 541...Winding temperature table

Claims

1. a voltage command generation unit that generates a voltage command for controlling an output voltage of a power conversion device to a motor having a rotor with a permanent magnet in accordance with a speed command or a torque command of the motor; a dead time compensation unit that performs dead time compensation on the voltage command; a magnetic flux estimation unit that estimates the magnetic flux of the permanent magnet; In a motor control device comprising: The magnetic flux estimation unit estimating a magnetic flux of the permanent magnet based on the voltage command and voltage drops occurring between the motor and the power conversion device, and between the motor and the power conversion device; The voltage drop is a first voltage drop component due to a resistance component between the motor and the power conversion device, and between the motor and the power conversion device; a second voltage drop component caused by the dead time compensation; and a third voltage drop component obtained by subtracting the first voltage drop component and the second voltage drop component from the voltage drop; and A motor control device comprising:

2. 2. The motor control device according to claim 1, a table showing a relationship between the voltage drop and the motor current at a predetermined rotation speed of the motor; A motor control device comprising: a motor control circuit for calculating the resistance component based on the table data and the second voltage drop component;

3. 2. The motor control device according to claim 1, A motor control device comprising: a motor control circuit for calculating the second voltage drop component based on a switching period, a DC voltage of a DC voltage source provided in the power conversion device, and a current phase angle.

4. 2. The motor control device according to claim 1, a first table data indicating a relationship between the voltage drop and the motor current at a predetermined rotation speed of the motor; calculating second table data representing a relationship between the third voltage drop component and a motor current based on the table data and the second voltage drop component; a motor control device that calculates the third voltage drop component based on the second table data;

5. 2. The motor control device according to claim 1, The motor control device according to claim 1, wherein the magnetic flux estimation unit estimates a temperature of the permanent magnet based on the estimated magnetic flux.

6. 2. The motor control device according to claim 1, A motor control device comprising: a motor control section for adjusting the speed command or the torque command based on the magnetic flux estimated by the magnetic flux estimation section;

7. 6. The motor control device according to claim 5, A motor control device comprising: a motor control section for adjusting the speed command or the torque command based on the temperature estimated by the magnetic flux estimation section;

8. 8. The motor control device according to claim 6 or 7, A motor control device characterized in that, when the speed command or the torque command exceeds a predetermined threshold, the speed command or the torque command is limited to a predetermined value.

9. 2. The motor control device according to claim 1, A motor control device characterized in that it issues a signal to an external device when the magnetic flux estimated by the magnetic flux estimation unit exceeds or falls below a predetermined value.

10. 6. The motor control device according to claim 5, A motor control device characterized in that it issues a signal to an external device when the temperature estimated by the magnetic flux estimation unit exceeds or falls below a predetermined value.

11. Wheels and a motor that drives the wheels; a power converter that supplies power to the motor; a control device that controls the power conversion device; In an electric vehicle system comprising:

6. An electric vehicle system, wherein the control device is the motor control device according to claim 1 or 5.

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