Control device, magnetic flux estimation device, and magnetic flux estimation method

Abstract

The present invention provides a power conversion device effective for improving reliability of motor control based on a result of estimation of primary magnetic flux. A control device (1) includes: a power conversion circuit (10) that supplies driving power to a motor (3); a magnetic flux estimation section (130) that estimates primary magnetic flux generated in the motor (3) by supply of the driving power; and a voltage command generation section (160) (control section) that controls the power conversion circuit (10) based on a result of estimation of the primary magnetic flux obtained by the magnetic flux estimation section (130), the magnetic flux estimation section (130) performs: a first estimation that estimates the primary magnetic flux based on an output current from the power conversion circuit (10) to the motor (3) and an inductance of the motor (3) in a case where an operation speed of the motor (3) is less than a prescribed level; and a second estimation that estimates a magnetic flux differential value based on an output voltage from the power conversion circuit (10) to the motor (3) in a case where the operation speed is greater than the prescribed level, and estimates the primary magnetic flux by integrating the magnetic flux differential value with a result of the first estimation as an initial value.

Description

Technical Field

[0001] The present disclosure relates to a control device, a magnetic flux estimating device, and a magnetic flux estimating method. Background Art

[0002] Patent Document 1 discloses a control device that smoothly converts stator flux calculation from a current model to a voltage model based on rotor speed.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application No. 2007-525137 Summary of the Invention

[0006] Problems to be solved by the invention

[0007] The present disclosure provides a power conversion device that is effective in improving the reliability of motor control based on a result of primary magnetic flux estimation.

[0008] Solutions for solving problems

[0009] A control device according to one aspect of the present disclosure comprises: a power conversion circuit for supplying driving power to an electric motor; a magnetic flux estimating unit for estimating the primary magnetic flux generated by the electric motor through the supply of driving power; and a control unit for controlling the power conversion circuit based on the estimation result of the primary magnetic flux obtained by the magnetic flux estimating unit, wherein the magnetic flux estimating unit performs the following estimations: a first estimation for estimating the primary magnetic flux based on the output current from the power conversion circuit to the electric motor and the inductance of the electric motor when the operating speed of the electric motor is less than a prescribed level; and a second estimation for estimating the magnetic flux differential value based on the output voltage from the power conversion circuit to the electric motor when the operating speed is greater than a prescribed level, wherein the estimation result of the primary magnetic flux obtained by the first estimation is used as an initial value, and the magnetic flux differential value is integrated to estimate the primary magnetic flux.

[0010] A flux estimating device according to another aspect of the present disclosure performs the following estimations: a first estimation, when the operating speed of the motor is less than a prescribed level, estimating the primary magnetic flux generated by the motor based on the output current from the power conversion circuit to the motor and the inductance of the motor; and a second estimation, when the operating speed is greater than a prescribed level, estimating the flux differential value based on the output voltage from the power conversion circuit to the motor, using the estimated result of the primary magnetic flux obtained by the first estimation as an initial value, and integrating the flux differential value to estimate the primary magnetic flux.

[0011] Another aspect of the flux estimation method disclosed herein includes: a first estimation, when the operating speed of the motor is less than a specified level, estimating the primary magnetic flux generated by the motor based on the output current from the power conversion circuit to the motor and the inductance of the motor; and a second estimation, when the operating speed is greater than a specified level, estimating the flux differential value based on the output voltage from the power conversion circuit to the motor, using the estimated result of the primary magnetic flux obtained by the first estimation as an initial value, and integrating the flux differential value to estimate the primary magnetic flux.

[0012] Beneficial effects

[0013] According to the present disclosure, it is possible to provide a power conversion device that is effective in improving the reliability of motor control based on the estimation result of the primary magnetic flux. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram showing an example of the configuration of the control device.

[0015] Figure 2 This is a block diagram illustrating the functional configuration of the magnetic flux estimating unit.

[0016] Figure 3 This is a graph showing an example of setting the correction gain and the cancellation gain.

[0017] Figure 4 This is a block diagram illustrating the hardware configuration of the control circuit.

[0018] Figure 5 is a flowchart illustrating the control process by way of example.

[0019] Figure 6 This is a flowchart illustrating the magnetic flux estimation process.

[0020] Figure 7 This is a block diagram showing a modified example of the magnetic flux estimating unit. DETAILED DESCRIPTION

[0021] Hereinafter, the embodiments will be described in detail with reference to the accompanying drawings. In the description, the same elements or elements having the same functions are denoted by the same reference numerals, and repeated descriptions are omitted.

[0022] [Control device]

[0023] Figure 1 The control device 1 shown is a device for controlling the motor 3. The control device 1 converts the power supplied from the power supply 2 into driving power and supplies it to the motor 3. The power supply 2 can be a DC power supply or an AC power supply. As an example, Figure 1The figure shows a case where the power source 2 is a three-phase AC power source. Specific examples of the three-phase AC power source include a power system of an electric power company, a three-phase AC generator, or an uninterruptible power supply.

[0024] Motor 3 is an AC motor that operates with AC drive power (e.g., three-phase AC power). Motor 3 may also be a synchronous motor. For example, Motor 3 is a PMA (Permanent Magnet Assistance) motor. Motor 3 may be an IPM (Interior Permanent Magnet) motor or an SPM (Surface Permanent Magnet) motor. Motor 3 may also be a synchronous reluctance motor without permanent magnets. Motor 3 may also be an induction motor.

[0025] The motor 3 may be a fixed coil type with a coil provided on a stator, or a movable coil type with a coil provided on a mover. Furthermore, the motor 3 may be a rotary type or a linear type.

[0026] The control device 1 includes a power conversion circuit 10 and a control circuit 100. The power conversion circuit 10 converts the power supplied from the power supply 2 (hereinafter referred to as "power supply power") into driving power and supplies it to the motor 3. As an example, the power conversion circuit 10 includes a rectifier circuit 11, a smoothing capacitor 12, an inverter circuit 13, and a current sensor 14. The rectifier circuit 11, such as a diode bridge circuit or a PWM converter circuit, converts the power supply power into DC power. The smoothing capacitor 12 smoothes the DC power.

[0027] The inverter circuit 13 performs power conversion between the DC power and the drive power. For example, in the power running state, the inverter circuit 13 converts the DC power into drive power and supplies it to the motor 3. In the regenerative state, the inverter circuit 13 converts the power generated by the motor 3 into DC power. It should be noted that the power running state refers to a state in which the motor 3 is operating with the drive power supplied by the inverter circuit 13, while the regenerative state refers to a state in which the motor 3 supplies the generated power corresponding to the operation to the inverter circuit 13.

[0028] For example, the inverter circuit 13 includes a plurality of switching elements 15, and performs the above-mentioned power conversion by switching the plurality of switching elements 15 on and off. The switching element 15 is, for example, a power MOSFET (Metal Oxide Semiconductor Field Effect Transistor) or an IGBT (Insulated Gate Bipolar Transistor), and is switched on and off in response to a gate drive signal.

[0029] The current sensor 14 detects the current flowing between the inverter circuit 13 and the motor 3 (hereinafter referred to as "output current"). For example, the current sensor 14 can be configured to detect the current of all three-phase AC phases (U phase, V phase, and W phase), or it can be configured to detect the current of any two phases of the three-phase AC. As long as zero-phase current is not generated, the sum of the currents of the U phase, V phase, and W phase is zero. Therefore, even when detecting the current of two phases, information on the current of all phases can be obtained.

[0030] The configuration of the power conversion circuit 10 described above is merely an example. The configuration of the power conversion circuit 10 can be modified in any manner as long as it can generate the driving power for the motor 3. For example, the rectifier circuit 11 may be a PWM converter circuit or a matrix converter circuit that converts AC power into DC power. The power conversion circuit 10 may also be a matrix converter circuit that performs bidirectional power conversion between the power supply power and the driving power without DC conversion. If the power supply power is DC power, the power conversion circuit 10 does not need to include the rectifier circuit 11.

[0031] The control circuit 100 controls the power conversion circuit 10 to supply drive power to the motor 3 in accordance with the control command. The control circuit 100 controls the power conversion circuit 10 based on the result of estimating the primary magnetic flux. More specifically, the control circuit 100 is configured to perform the following operations: estimate the primary magnetic flux generated by the supply of drive power to the motor 3; estimate the electromagnetic force of the motor 3 based on the estimated primary magnetic flux and the output current (the current detected by the current sensor 14); and control the power conversion circuit 10 based on the deviation between the target magnetic flux and the estimated primary magnetic flux and the deviation between the target electromagnetic force and the estimated electromagnetic force. Therefore, the control circuit 100 includes a magnetic flux estimation device for estimating the primary magnetic flux.

[0032] For example, the control circuit 100 includes, as functional elements, an electromagnetic force command generating unit 110 , a magnetic flux command generating unit 120 , a current information acquiring unit 101 , a magnetic flux estimating unit 130 , an electromagnetic force estimating unit 150 , a voltage command generating unit 160 , a phase angle calculating unit 170 , and a PWM control unit 180 .

[0033] The electromagnetic force command generator 110 generates the target electromagnetic force to cause the motor 3 to perform the desired operation. The term "electromagnetic force" simply refers to a value related to the force applied by the motor 3 to the driven object. If the motor 3 is a rotary motor, the electromagnetic force can be the torque generated by the motor 3 around its axis of rotation. If the motor 3 is a linear motor, the electromagnetic force can be the thrust generated by the motor 3 in the direction of movement of the mover.

[0034] As an example, the electromagnetic force command generating unit 110 calculates a speed deviation as the difference between the target speed ωt and the estimated speed value ω, as shown at addition point 111. The target speed ωt is, for example, a target value of the angular velocity of the electrical angle, and the estimated speed value ω is an estimated value of the angular velocity of the electrical angle. The electromagnetic force command generating unit 110 can obtain the target speed ωt pre-stored in the control circuit 100 or from a higher-level controller such as a programmable logic controller. As shown in block 112, the electromagnetic force command generating unit 110 performs a proportional operation, a proportional / integral operation, or a proportional / integral / differential operation on the speed deviation to calculate the target torque Tt (target electromagnetic force).

[0035] The flux command generating unit 120 calculates the target primary magnetic flux Φt based on the target torque Tt, the magnet flux of the motor 3, and the inductance of the motor 3. For example, if the motor 3 is a synchronous motor other than a synchronous reluctance motor, the flux command generating unit 120 calculates the target current based on the target torque Tt and calculates the target primary magnetic flux Φt using the following formula.

[0036] Φdt=Ld·Idt+Φm

[0037] Φqt=Lq·Iqt

[0038] Φt=(Φdt 2 +Φqt 2 ) 1 / 2 ……(1)

[0039] Φdt: d-axis primary magnetic flux target value

[0040] Φqt: q-axis primary magnetic flux target value

[0041] Ld: d-axis inductance

[0042] Lq: q-axis inductance

[0043] Idt: d-axis current target value

[0044] Iqt: q-axis current target value

[0045] Φm: Magnet flux

[0046] If the motor 3 is a synchronous reluctance motor, the magnet flux Φm in equation (1) is zero. If the motor 3 is an induction motor, the d-axis inductance Ld is replaced by the primary inductance L1. The q-axis inductance Lq is replaced by a leakage inductance equivalent to the sum of the primary leakage inductance l1 and the secondary leakage inductance l2.

[0047] The d-axis and q-axis are coordinate axes of the dq coordinate system, which is a rotating coordinate system, and are respectively perpendicular to the rotation axis of the motor 3. When the motor 3 is a PMA, the d-axis is, for example, along the direction of the magnet flux, and the q-axis is perpendicular to the direction of the magnet flux. The origin where the d-axis and the q-axis intersect is located at the rotation center of the motor 3. When the motor 3 is an induction motor, the d-axis is, for example, along the direction of the gap flux, and the q-axis is perpendicular to the direction of the gap flux. When the motor 3 is a synchronous reluctance motor, the d-axis is along the direction of the salient poles of the rotor, and the q-axis is perpendicular to the direction of the salient poles. In addition, when the motor 3 is a synchronous reluctance motor, the d-axis and q-axis are coordinate axes of the dq coordinate system that rotate together with the salient poles of the rotor, and the d-axis is along the direction of the salient poles.

[0048] The d-axis flux is the d-axis component of the primary magnetic flux, and the q-axis flux is the q-axis component of the primary magnetic flux. The d-axis current is the current that generates magnetic flux along the d-axis, and the q-axis current is the current that generates magnetic flux along the q-axis. The d-axis inductance is the coefficient that determines the d-axis flux from the d-axis current, and the q-axis inductance is the coefficient that determines the q-axis flux from the q-axis current.

[0049] The current information acquisition unit 101 acquires the output current detection result from the current sensor 14 and performs a three-phase / two-phase conversion on the acquired detection result to calculate the a-axis current Ia and the b-axis current Ib. The a-axis current Ia is the a-axis component of the output current, and the b-axis current Ib is the b-axis component of the output current.

[0050] The a-axis and the b-axis are coordinate axes of the ab coordinate system, which is a fixed coordinate system, and are perpendicular to the rotation axis of the motor 3. The a-axis and the b-axis are perpendicular to each other, and the origin where the a-axis and the b-axis intersect coincides with the rotation center of the motor 3.

[0051] The magnetic flux estimation unit 130 estimates the primary magnetic flux generated by the motor 3 in response to the supply of drive power. For example, the magnetic flux estimation unit 130 calculates an estimated primary magnetic flux value Φ, an estimated a-axis primary magnetic flux value Φa, and an estimated b-axis primary magnetic flux value Φb. The a-axis magnetic flux is the a-axis component of the primary magnetic flux, and the b-axis magnetic flux is the b-axis component of the primary magnetic flux. The primary magnetic flux estimation process performed by the magnetic flux estimation unit 130 will be described later.

[0052] The electromagnetic force estimation unit 150 estimates the torque (electromagnetic force) of the motor 3 based on the estimation result of the primary magnetic flux and the output current. For example, the electromagnetic force estimation unit 150 calculates the torque estimation value T using the following formula.

[0053] T=Φa·Ib-Φb·Ia……(2)

[0054] The voltage command generating unit 160 (control unit) controls the power conversion circuit 10 based on the primary magnetic flux estimation result obtained by the magnetic flux estimation unit 130. For example, the voltage command generating unit 160 controls the power conversion circuit 10 based on the deviation between the target magnetic flux and the estimated primary magnetic flux and the deviation between the target electromagnetic force and the estimated electromagnetic force.

[0055] As an example, the voltage command generation unit 160 generates a voltage command to minimize the deviation between the target magnetic flux Φt and the estimated primary magnetic flux value Φ, thereby minimizing the deviation between the target torque Tt and the estimated torque value T. For example, the voltage command generation unit 160 generates a voltage command in a γδ coordinate system that rotates with the primary magnetic flux. The γ and δ axes of the γδ coordinate system are perpendicular to the rotation axis of the motor 3. The origin where the γ and δ axes intersect is located at the rotation center of the motor 3. The γ axis is along the direction of the primary magnetic flux, and the δ axis is perpendicular to the direction of the primary magnetic flux. For example, as shown at addition point 161, the voltage command generation unit 160 calculates a magnetic flux deviation, which is the difference between the target magnetic flux Φt and the estimated primary magnetic flux value Φ. As shown at block 162, the voltage command generation unit 160 performs a proportional operation, a proportional / integral operation, or a proportional / integral / differential operation on the magnetic flux deviation to calculate a γ-axis voltage command Vγ. The γ-axis voltage command Vγ is the γ-axis component of the voltage command.

[0056] In addition, the voltage command generating unit 160 calculates a torque deviation as the difference between the target torque Tt and the torque estimated value T as shown in the addition point 163, divides the torque deviation by the primary magnetic flux estimated value Φ as shown in block 164, and performs a proportional operation, a proportional / integral operation, or a proportional / integral / differential operation on the division result as shown in block 165 to calculate the torque control voltage.

[0057] Furthermore, as shown in block 166, voltage command generator 160 multiplies primary magnetic flux estimate Φ by speed estimate ω to calculate the induced voltage. Next, as shown in addition point 167, voltage command generator 160 adds the torque control voltage to the induced voltage to calculate the delta-axis voltage command Vδ. The delta-axis voltage command Vδ is the delta-axis component of the voltage command.

[0058] The phase angle calculation unit 170 calculates an estimated speed value ω and an estimated phase angle value θ by inputting the estimated a-axis magnetic flux value Φa and the estimated b-axis magnetic flux value Φb into a phase-locked loop. The estimated speed value ω is an estimate of the rotational speed of the primary magnetic flux, and the estimated phase angle value θ is an estimate of the rotational angle of the primary magnetic flux. The estimated speed value ω calculated by the phase angle calculation unit 170 is fed back to the electromagnetic force command generation unit 110 and used to calculate the target torque Tt. Furthermore, the estimated speed value ω calculated by the phase angle calculation unit 170 is also used in the calculation of the induced voltage by the voltage command generation unit 160.

[0059] The PWM control unit 180 controls the power conversion circuit 10 to generate a voltage corresponding to the voltage command generated by the voltage command generation unit 160. For example, the PWM control unit 180 performs rotational conversion on the γ-axis voltage command Vγ and the δ-axis voltage command Vδ based on the phase angle estimate θ to calculate the a-axis voltage command Va and the b-axis voltage command Vb. The PWM control unit 180 then performs two-phase / three-phase conversion on the a-axis voltage command Va and the b-axis voltage command Vb to calculate the phase voltage commands for the drive power. The PWM control unit 180 switches the multiple switching elements 15 of the inverter circuit 13 on and off to apply a three-phase AC voltage corresponding to the phase voltage commands to the motor 3.

[0060] In this way, the power conversion circuit 10 is controlled to generate a voltage corresponding to the voltage command generated by the voltage command generation unit 160. Therefore, the power conversion circuit 10 is controlled based on the deviation between the target magnetic flux and the estimated result of the primary magnetic flux and the deviation between the target electromagnetic force and the estimated result of the electromagnetic force.

[0061] The following specifically illustrates the primary magnetic flux estimation process performed by the magnetic flux estimation unit 130. The magnetic flux estimation unit 130 is configured to perform the following estimations: a first estimation, when the operating speed of the motor 3 is less than a predetermined level, estimates the primary magnetic flux based on the output current from the power conversion circuit 10 to the motor 3 and the inductance of the motor 3; and a second estimation, when the operating speed of the motor 3 is greater than a predetermined level, estimates the magnetic flux differential value based on the output voltage from the power conversion circuit 10 to the motor 3. The primary magnetic flux is estimated by integrating the magnetic flux differential value using the primary magnetic flux estimation result obtained by the first estimation as an initial value. It should be noted that the operating speed can refer to a frequency command (a speed command in the case of a synchronous motor) or a speed estimate.

[0062] During the first estimation, magnetic flux estimating unit 130 only needs to estimate the primary magnetic flux based on at least the output current and inductance. It may also simultaneously estimate the primary magnetic flux based on the output voltage. For example, during the first estimation, magnetic flux estimating unit 130 may calculate the magnetic flux differential value based on the output voltage, correct the magnetic flux differential value based on the output current and inductance, and then integrate the corrected magnetic flux differential value to calculate the primary magnetic flux.

[0063] Alternatively, when the operating speed of the motor 3 is less than a specified level, the flux estimation unit 130 repeatedly performs the first estimation, and in each first estimation, the flux differential value is calculated based on the output voltage, and a reference estimation is performed to estimate the primary flux based on the output current and inductance, and a correction value is calculated based on the deviation between the estimated result of the primary flux obtained by the previous first estimation and the estimated result of the primary flux obtained by the reference estimation, and the flux differential value is corrected based on the correction value.

[0064] Alternatively, the magnetic flux estimating unit 130 may reduce the correction of the magnetic flux differential value based on the output current and inductance during the first estimation as the operating speed approaches a predetermined level. Reducing the correction means reducing the extent to which the correction value calculated based on the output current and inductance is reflected in the magnetic flux differential value. As an example, the magnetic flux estimating unit 130 calculates the correction value based on the value obtained by multiplying the correction value calculated based on the output current and inductance by a correction gain, and reduces the correction gain as the operating speed approaches the predetermined level.

[0065] Magnetic flux estimation unit 130 can use the a-axis voltage command Va and the b-axis voltage command Vb as the output voltage. Alternatively, magnetic flux estimation unit 130 can use the voltage detected by the sensor as the output voltage. Alternatively, magnetic flux estimation unit 130 can use the a-axis current Ia and the b-axis current Ib as the output current.

[0066] Figure 2 This block diagram illustrates the functional configuration of magnetic flux estimation unit 130 when motor 3 is a synchronous motor. As shown in block 131, magnetic flux estimation unit 130 multiplies a-axis current Ia and b-axis current Ib by winding resistance r to calculate the voltage drop in the winding. As shown in addition point 143, magnetic flux estimation unit 130 subtracts the voltage drop from a-axis voltage command Va and b-axis voltage command Vb to calculate the magnetic flux differential value. For example, magnetic flux estimation unit 130 calculates the magnetic flux differential value using the following formula.

[0067] Φa'=Va-r·Ia

[0068] Φb'=Vb-r·Ib……(3)

[0069] Φa': a-axis magnetic flux differential value

[0070] Φb': b-axis magnetic flux differential value

[0071] r: winding resistance

[0072] The magnetic flux estimation unit 130 performs rotation conversion on the a-axis current Ia and the b-axis current Ib to calculate the d-axis current Id and the q-axis current Iq as shown in block 132. The d-axis current Id is the d-axis component of the output current, and the q-axis current Iq is the q-axis component of the output current.

[0073] To convert a-axis current Ia and b-axis current Ib into d-axis current Id and q-axis current Iq, magnetic flux estimation unit 130 calculates an estimated phase angle θd of the dq coordinate system relative to the ab coordinate system based on a-axis current Ia, b-axis current Ib, a-axis voltage command Va, and b-axis voltage command Vb, as shown in block 148. For example, magnetic flux estimation unit 130 calculates the estimated phase angle θd using an extended induced voltage observer. More specifically, magnetic flux estimation unit 130 calculates the estimated phase angle θd using a phase-locked loop (PLL) to minimize the d-axis component of the induced voltage in the dq coordinate system to zero. It should be noted that the induced voltage in the dq coordinate system is calculated based on the d-axis current Id and the q-axis current Iq obtained by performing a rotation transformation on the a-axis current Ia and the b-axis current Ib according to the phase angle estimation value θd, and the d-axis voltage command Vd and the q-axis voltage command Vq obtained by performing a rotation transformation on the a-axis voltage command Va and the b-axis voltage command Vb according to the phase angle estimation value θd.

[0074] Furthermore, as shown by block 133 and summing point 144, magnetic flux estimation unit 130 performs a reference estimate of the primary magnetic flux based on the d-axis current Id and q-axis current Iq, the d-axis inductance Ld and q-axis inductance Lq, and the magnet magnetic flux Φm (which is zero when motor 3 is a synchronous reluctance motor). For example, magnetic flux estimation unit 130 calculates a reference estimate of the primary magnetic flux using the following formula.

[0075] Φdr=Ld·Id+Φm

[0076] Φqr=Lq·Iq……(4)

[0077] Φdr: d-axis magnetic flux reference estimated value

[0078] Φqr: q-axis magnetic flux reference estimated value

[0079] As shown in block 134, the magnetic flux estimating unit 130 applies rotational conversion based on the phase angle estimated value θd to the previously estimated a-axis magnetic flux value Φa and b-axis magnetic flux value Φb to calculate a d-axis magnetic flux estimated value Φd and a q-axis magnetic flux estimated value Φq. The d-axis magnetic flux estimated value Φd represents the d-axis component of the primary magnetic flux, and the q-axis magnetic flux estimated value Φq represents the q-axis component of the primary magnetic flux. As shown in addition point 145, the magnetic flux estimating unit 130 calculates a magnetic flux error, which is the difference between the d-axis magnetic flux reference estimated value Φdr and the d-axis magnetic flux estimated value Φd, and the difference between the q-axis magnetic flux reference estimated value Φqr and the q-axis magnetic flux estimated value Φq.

[0080] Furthermore, as shown in block 135, the magnetic flux estimation unit 130 performs a proportional operation, a proportional / integral operation, or a proportional / integral / differential operation on the magnetic flux error to calculate correction values ​​ΔΦd' and ΔΦq'. Furthermore, as shown in block 136, the magnetic flux estimation unit 130 performs a rotational transformation based on the phase angle estimated value θ on the correction values ​​ΔΦd' and ΔΦq' to calculate correction values ​​ΔΦa' and ΔΦb'. It should be noted that the magnetic flux estimation unit 130 may also use the phase angle estimated value θ instead of the phase angle estimated value θd for the rotational transformation in blocks 134 and 136. In this case, two rotational transformations (not shown) based on the phase angle estimated value θ and the phase angle estimated value θd are required between addition points 144 and 145.

[0081] Furthermore, instead of converting the a-axis magnetic flux estimation value Φa and the b-axis magnetic flux estimation value Φb into the d-axis magnetic flux estimation value Φd and the q-axis magnetic flux estimation value Φq in block 134, the d-axis magnetic flux reference estimation value Φdr and the q-axis magnetic flux reference estimation value Φqr may be subjected to rotation conversion based on the phase angle estimation value θd to calculate the a-axis magnetic flux reference estimation value Φar and the b-axis magnetic flux reference estimation value Φbr, and the flux error may be calculated as the difference between the a-axis magnetic flux reference estimation value Φar and the a-axis magnetic flux estimation value Φa and the difference between the b-axis magnetic flux reference estimation value Φbr and the b-axis magnetic flux estimation value Φb (see FIG. 1 ). Figure 7 134A).

[0082] In this case, the calculation of the correction value in block 135 can be performed in the γδ coordinate system or in the dq axis coordinate system. When the correction value is calculated in the γδ coordinate system, the flux error can be calculated by performing a rotation transformation based on the phase angle estimated value θ on the flux error (see Figure 7 In block 136A), correction values ​​ΔΦγ' and ΔΦδ' in the γδ coordinate system are calculated in block 135, and correction values ​​ΔΦγ' and ΔΦδ' are subjected to rotation conversion based on the phase angle estimation value θ to calculate correction values ​​ΔΦa' and ΔΦb' (refer to Figure 7 In the case of the dq axis coordinate system, the phase angle estimation value θd is used to perform the Figure 7 The coordinates of block 136A and block 136B can be converted (not shown).

[0083] Furthermore, as shown by block 137 and addition point 146, magnetic flux estimation unit 130 multiplies correction values ​​ΔΦa' and ΔΦb' by correction gain AK and adds the multiplication result to a-axis magnetic flux differential value Φa' and b-axis magnetic flux differential value Φb', respectively. This corrects a-axis magnetic flux differential value Φa' and b-axis magnetic flux differential value Φb', reducing the aforementioned magnetic flux error.

[0084] The magnetic flux estimating unit 130 integrates the corrected a-axis magnetic flux differential value Φa′ and b-axis magnetic flux differential value Φb′, as shown in block 138 , to calculate an a-axis magnetic flux estimated value Φa and a b-axis magnetic flux estimated value Φb.

[0085] The magnetic flux estimation unit 130 may also gradually reduce the correction gain AK as the speed estimation value ω increases. Figure 3 As shown in (a) of FIG. 1 , the magnetic flux estimation unit 130 sets the correction gain AK to a predetermined value AK1 when the estimated speed value ω is less than or equal to a threshold value ω1. When the estimated speed value ω is greater than or equal to a threshold value ω2, which is greater than the threshold value ω1, the correction gain AK is set to a predetermined value AK2, which is less than the predetermined value AK1. Furthermore, the magnetic flux estimation unit 130 gradually changes the correction gain AK from the predetermined value AK1 to the predetermined value AK2 as the estimated speed value approaches the threshold value ω2 from the threshold value ω1.

[0086] The estimation of the a-axis magnetic flux estimated value Φa and the b-axis magnetic flux estimated value Φb by the magnetic flux estimation unit 130 when the estimated speed value ω is less than the threshold value ω2 corresponds to the first estimation described above. The estimation of the a-axis magnetic flux estimated value Φa and the b-axis magnetic flux estimated value Φb by the magnetic flux estimation unit 130 when the estimated speed value ω is greater than the threshold value ω2 corresponds to the second estimation described above.

[0087] Alternatively, magnetic flux estimation unit 130 may stop correcting the magnetic flux differential value based on the output current and inductance during the second estimation. As an example, predetermined value AK2 may be zero. In this case, when speed estimate value ω is greater than threshold value ω2, correction of a-axis magnetic flux differential value Φa' and b-axis magnetic flux differential value Φb' based on correction values ​​ΔΦa' and ΔΦb' is stopped. While correction of a-axis magnetic flux differential value Φa' and b-axis magnetic flux differential value Φb' based on correction values ​​ΔΦa' and ΔΦb' is stopped, magnetic flux estimation unit 130 calculates a-axis magnetic flux differential value Φa' and b-axis magnetic flux differential value Φb' without using d-axis inductance Ld and q-axis inductance Lq.

[0088] Note that the predetermined value AK2 may be greater than 0. If the predetermined value AK2 is greater than 0, in the second estimation, correction is performed based on the output current and the magnetic flux differential value of the inductance using a correction gain AK smaller than the correction gain AK in the first estimation.

[0089] Back to Figure 2 Alternatively, the magnetic flux estimating unit 130 may remove the steady-state component that does not vary with the operation of the motor 3 from the primary magnetic flux estimation result. Alternatively, the magnetic flux estimating unit 130 may perform low-pass filtering on the primary magnetic flux estimation result during the removal of the steady-state component, and remove the filtered primary magnetic flux estimation result (the steady-state component extracted by filtering) from the primary magnetic flux estimation result before filtering. For example, as shown in blocks 139 and 141, the magnetic flux estimating unit 130 may perform low-pass filtering on the estimation results of the a-axis magnetic flux estimated value Φa and the b-axis magnetic flux estimated value Φb, multiply the filtered results by the cancellation gain CK, and convert the steady-state components included in the primary magnetic flux estimation result into current correction values ​​ΔIa and ΔIb.

[0090] As indicated by addition point 147, magnetic flux estimation unit 130 adds current correction values ​​ΔIa and ΔIb to the a-axis current Ia and b-axis current Ib before they are input to block 131 (multiplied by winding resistance r). Consequently, at addition point 143, in addition to the aforementioned voltage drop, a value obtained by multiplying current correction values ​​ΔIa and ΔIb by winding resistance r (hereinafter referred to as the "offset value") is subtracted. This offset value is thus removed from the subsequently calculated a-axis magnetic flux estimate Φa and b-axis magnetic flux estimate Φb.

[0091] The offset value corresponds to the filtered a-axis magnetic flux estimate Φa and b-axis magnetic flux estimate Φb. Therefore, removing the offset value from the subsequently calculated a-axis magnetic flux estimate Φa and b-axis magnetic flux estimate Φb is equivalent to removing the filtered a-axis magnetic flux estimate Φa and b-axis magnetic flux estimate Φb from the pre-filtered a-axis magnetic flux estimate Φa and b-axis magnetic flux estimate Φb. Note that, instead of adding the filtered result to the a-axis current Ia and b-axis current Ib, the filtered result can be subtracted from the a-axis magnetic flux differential value Φa' and b-axis magnetic flux differential value Φb', or from the a-axis voltage command Va and b-axis voltage command Vb.

[0092] The magnetic flux estimation unit 130 may gradually increase the cancellation gain CK as the speed estimation value ω increases. The magnetic flux estimation unit 130 may also make the cancellation gain CK during the second estimation period larger than the cancellation gain CK during the first estimation period.

[0093] For example, Figure 3As shown in (b) of FIG. 1 , magnetic flux estimation unit 130 sets cancellation gain CK to a predetermined value CK1 when estimated speed value ω is less than or equal to threshold value ω2. When estimated speed value ω is greater than or equal to threshold value ω3, which is greater than threshold value ω2, magnetic flux estimation unit 130 sets cancellation gain CK to a predetermined value CK2, which is greater than predetermined value CK1. Furthermore, magnetic flux estimation unit 130 gradually shifts cancellation gain CK from predetermined value CK1 to predetermined value CK2 as estimated speed value ω approaches threshold value ω3 from threshold value ω2.

[0094] Alternatively, magnetic flux estimation unit 130 may stop removing the steady-state component during at least a portion of the first estimation period. For example, predetermined value CK1 may be zero. In this case, when estimated speed value ω is less than threshold value ω2, removal of the steady-state component from estimated a-axis magnetic flux value Φa and estimated b-axis magnetic flux value Φb is stopped.

[0095] It should be noted that the predetermined value CK1 may be greater than 0. When the predetermined value CK1 is greater than 0, in the first estimation, the steady-state component is removed with a cancellation gain CK smaller than the cancellation gain CK in the second estimation.

[0096] The primary magnetic flux estimation process described above is merely an example. As long as the contributions of the output current and inductance in the second estimation are smaller than those in the first estimation, and the integration of the primary magnetic flux in the second estimation is performed using the primary magnetic flux estimation result from the first estimation as the initial value, the primary magnetic flux estimation process can be appropriately modified.

[0097] For example, in the first estimation, instead of integrating the magnetic flux differential value, the primary magnetic flux can be estimated based on the output current and inductance. For example, in the first estimation, the magnetic flux estimation unit 130 can perform a rotational transformation based on the phase angle estimate θd on the d-axis magnetic flux reference estimate value Φdr and the q-axis magnetic flux reference estimate value Φqr to calculate the a-axis magnetic flux estimate value Φa and the b-axis magnetic flux estimate value Φb. In this case, the accuracy of the primary magnetic flux estimation obtained by the second estimation can be improved by starting the integration of the magnetic flux differential value in the second estimation using the primary magnetic flux estimation result obtained by the first estimation as the initial value.

[0098] As described above, the motor 3 may be an induction motor. In this case, the magnetic flux estimation unit 130 calculates the a-axis magnetic flux reference estimated value Φar and the b-axis magnetic flux reference estimated value Φbr in the ab coordinate system, which is a fixed coordinate system, using the following equations, for example.

[0099] Φar=M·(Φ2a-M·I1a) / L2+L1·I1a

[0100] Φbr=M·(Φ2b-M·I1b) / L2+L1·I1b......(5)

[0101] L1: primary inductor

[0102] L2: Secondary inductor

[0103] M: Mutual inductance between primary and secondary sides

[0104] I1a: a-axis component of the primary current

[0105] I1b: b-axis component of the primary current

[0106] Φ2a: a-axis component of the secondary magnetic flux

[0107] Φ2b: b-axis component of the secondary magnetic flux

[0108] The d-axis magnetic flux reference estimated value Φdr and the q-axis magnetic flux reference estimated value Φqr are calculated by performing rotation conversion based on the phase angle estimated value θd on the a-axis magnetic flux reference estimated value Φar and the b-axis magnetic flux reference estimated value Φbr.

[0109] Figure 4 1 is a block diagram showing an example of the hardware configuration of the control circuit 100. Figure 4 As shown, the control circuit 100 includes a processor 191, a memory 192, a storage 193, an input / output port 194, and a switch control circuit 195. The processor 191 may include multiple processing devices, the memory 192 may include multiple memory devices, and the storage 193 may include multiple memory devices.

[0110] Memory 193 comprises a computer-readable storage medium, such as a nonvolatile semiconductor memory. Memory 193 stores a program for causing control circuit 100 to execute the following operations: estimating the primary magnetic flux generated by the supply of drive power to motor 3; estimating the electromagnetic force of motor 3 based on the estimated primary magnetic flux and the output current; and controlling power conversion circuit 10 based on the deviation between the estimated primary magnetic flux and the target magnetic flux and the deviation between the estimated electromagnetic force and the target electromagnetic force. The program is configured to cause the control circuit 100 (magnetic flux estimating device) to perform the following estimations: a first estimation of the primary magnetic flux based on the output current from the power conversion circuit 10 to the motor 3 and the inductance of the motor 3 when the rotational speed (operating speed) of the motor 3 is less than a predetermined level; and a second estimation of the magnetic flux differential value based on the output voltage from the power conversion circuit 10 to the motor 3 when the rotational speed of the motor 3 is greater than a predetermined level. The primary magnetic flux is estimated by integrating the magnetic flux differential value using the primary magnetic flux estimation result obtained by the first estimation as an initial value. For example, the memory 193 stores a program for causing the control circuit 100 to configure the aforementioned functional elements.

[0111] Memory 192 temporarily stores programs loaded from the storage medium of storage 193 and calculation results obtained by processor 191. Processor 191 executes these programs in cooperation with memory 192 to implement the functional elements of control circuit 100. Input / output port 194 inputs and outputs electrical signals to and from current sensor 14 in accordance with instructions from processor 191. Switch control circuit 195 outputs drive signals for switching multiple switching elements 15 on and off to inverter circuit 13 in accordance with instructions from processor 191.

[0112] It should be noted that the control circuit 100 is not necessarily limited to configuring each function by a program. For example, the control circuit 100 may configure at least a portion of its functions by a dedicated logic circuit or an ASIC (Application Specific Integrated Circuit) integrating the dedicated logic circuit.

[0113] Control process

[0114] Next, a control process executed by control circuit 100 is described as an example of a control method. This process includes: estimating the primary magnetic flux generated by motor 3 through the supply of drive power; estimating the electromagnetic force of motor 3 based on the estimated primary magnetic flux and the output current; and controlling power conversion circuit 10 based on the deviation between the estimated primary magnetic flux and the target magnetic flux and the deviation between the estimated electromagnetic force and the target electromagnetic force.

[0115] like Figure 5 As shown, the control circuit 100 sequentially executes steps S01, S02, S03, S04, S05, S06, S07, and S08. In step S01, the electromagnetic force command generator 110 generates the target electromagnetic force to cause the motor 3 to perform the desired operation. For example, the electromagnetic force command generator 110 calculates a speed deviation, which is the difference between the target speed ωt and the estimated speed value ω, and performs a proportional operation, a proportional / integral operation, or a proportional / integral / differential operation on the speed deviation to calculate the target torque Tt. In step S02, the magnetic flux command generator 120 calculates the target magnetic flux Φt based on the target torque Tt and the inductance of the motor 3.

[0116] In step S03, the current information acquisition unit 101 acquires the detection result of the output current obtained by the current sensor 14, performs three-phase / two-phase conversion on the acquired detection result to calculate the a-axis current Ia and the b-axis current Ib. In step S04, the magnetic flux estimation unit 130 estimates the primary magnetic flux generated by the motor 3 through the supply of driving power. The specific content of step S04 will be described later. In step S05, the electromagnetic force estimation unit 150 estimates the torque (electromagnetic force) of the motor 3 based on the estimation result of the primary magnetic flux and the output current. In step S06, the phase angle calculation unit 170 calculates the speed estimation value ω and the phase angle estimation value θ by inputting the a-axis magnetic flux estimation value Φa and the b-axis magnetic flux estimation value Φb into the phase-locked loop.

[0117] In step S07, the voltage command generator 160 generates a voltage command to reduce the deviation between the target magnetic flux Φt and the primary magnetic flux estimate Φ, thereby reducing the deviation between the target torque Tt and the torque estimate T. In step S08, the PWM controller 180 begins turning on and off the multiple switching elements 15 of the inverter circuit 13 to generate a voltage corresponding to the voltage command generated by the voltage command generator 160. For example, the PWM controller 180 performs rotational conversion based on the phase angle estimate θ on the d-axis voltage command Vd and the q-axis voltage command Vq to calculate the a-axis voltage command Va and the b-axis voltage command Vb. The PWM controller 180 then performs a three-phase / two-phase conversion on the a-axis voltage command Va and the b-axis voltage command Vb to calculate phase voltage commands for the drive power, and then begins turning on and off the multiple switching elements 15 based on the phase voltage commands. The control circuit 100 repeatedly executes the above process.

[0118] The estimated speed value ω calculated in step S06 is used to calculate the speed deviation in step S01 of the next cycle and to generate the voltage command in step S07 of the next cycle. Furthermore, the a-axis voltage command Va and the b-axis voltage command Vb calculated in step S08 are used to estimate the primary magnetic flux in step S04 of the next cycle. Furthermore, the estimated speed value ω and the estimated phase angle value θ calculated in step S06 are also used to estimate the primary magnetic flux in step S04 of the next cycle.

[0119] Next, the primary magnetic flux estimation process in step S04 is described as an example of a magnetic flux estimation method. This process includes a first estimation of the primary magnetic flux generated by motor 3 based on the output current from power conversion circuit 10 to motor 3 and the inductance of motor 3 when the operating speed of motor 3 is less than a predetermined level; and a second estimation of the magnetic flux differential value based on the output voltage from power conversion circuit 10 to motor 3 when the operating speed is greater than the predetermined level. The primary magnetic flux is estimated by integrating the magnetic flux differential value using the primary magnetic flux estimation result obtained in the first estimation as an initial value.

[0120] It should be noted that according to Figure 2 In the block diagram, the calculation of the correction values ​​ΔΦa' and ΔΦb' is continued during the period when the correction gain AK is set to zero, but the calculation of the correction values ​​ΔΦa' and ΔΦb' itself may be stopped during the period when the correction gain AK is set to zero. Figure 2 The block diagram shows that the calculation of current correction values ​​ΔIa and ΔIb continues even when the cancellation gain CK is set to zero. However, the calculation of current correction values ​​ΔIa and ΔIb can also be stopped during the period when the cancellation gain CK is set to zero. The following example illustrates a process in which the calculation of correction values ​​ΔΦa' and ΔΦb' is stopped while the correction gain AK is set to zero, and the calculation of current correction values ​​ΔIa and ΔIb is stopped while the cancellation gain CK is set to zero.

[0121] like Figure 6 As shown, the control circuit 100 first executes step S11. In step S11, the magnetic flux estimation unit 130 checks whether the operating speed (for example, the speed estimated value ω calculated in the previous step S06) is greater than the threshold value ω2.

[0122] If it is determined in step S11 that the operating speed is not greater than the threshold value ω2, the control circuit 100 executes steps S12, S13, S14, S15, and S16. In step S12, the magnetic flux estimation unit 130 multiplies the a-axis current Ia and b-axis current Ib calculated in step S03 by the winding resistance r to calculate the voltage drop in the winding. The a-axis magnetic flux differential value Φa' and the b-axis magnetic flux differential value Φb' are calculated by subtracting the voltage drop from the a-axis voltage command Va and the b-axis voltage command Vb (the a-axis voltage command Va and the b-axis voltage command Vb calculated in step S08 in the previous cycle).

[0123] In step S13 , the magnetic flux estimating unit 130 performs a reference estimation of the primary magnetic flux based on the a-axis current Ia and the b-axis current Ib, the d-axis inductance Ld and the q-axis inductance Lq, and the magnet magnetic flux Φm, and calculates the d-axis magnetic flux reference estimation value Φdr and the q-axis magnetic flux reference estimation value Φqr.

[0124] In step S14, the magnetic flux estimation unit 130 performs rotational conversion on the a-axis magnetic flux estimate Φa and the b-axis magnetic flux estimate Φb based on the phase angle estimate θd to calculate the d-axis magnetic flux estimate Φd and the q-axis magnetic flux estimate Φq. The unit then calculates flux errors as the difference between the d-axis magnetic flux reference estimate Φdr and the d-axis magnetic flux estimate Φd, and the difference between the q-axis magnetic flux reference estimate Φqr and the q-axis magnetic flux estimate Φq. Furthermore, the flux errors are subjected to a proportional operation, a proportional / integral operation, or a proportional / integral / differential operation to calculate correction values ​​ΔΦd' and ΔΦq'. In step S15, the magnetic flux estimation unit 130 calculates a correction gain AK based on the speed estimate ω. In step S16 , the magnetic flux estimating unit 130 corrects the a-axis magnetic flux differential value Φa′ and the b-axis magnetic flux differential value Φb′ calculated in step S12 by adding a value obtained by multiplying the correction values ​​ΔΦa′ and ΔΦb′ by the correction gain AK.

[0125] If the operating speed is determined to be greater than the threshold value ω2 in step S11, the control circuit 100 executes steps S21, S22, S23, S24, and S25. In step S21, the magnetic flux estimation unit 130 calculates the steady-state components of the a-axis magnetic flux estimate Φa and the b-axis magnetic flux estimate Φb by low-pass filtering the a-axis magnetic flux estimate Φa and the b-axis magnetic flux estimate Φb calculated in the previous cycle. In step S22, the magnetic flux estimation unit 130 calculates the cancellation gain CK based on the operating speed. In step S23, the magnetic flux estimation unit 130 calculates current correction values ​​ΔIa and ΔIb by multiplying the steady-state components by the cancellation gain CK. These current correction values ​​ΔIa and ΔIb are then added to correct the a-axis current Ia and b-axis current Ib calculated in step S03.

[0126] In step S24, the flux estimation unit 130 multiplies the a-axis current Ia and the b-axis current Ib corrected in step S23 by the winding resistance r to calculate the voltage drop in the winding, and subtracts the voltage drop from the a-axis voltage command Va and the b-axis voltage command Vb (the a-axis voltage command Va and the b-axis voltage command Vb calculated in step S08 of the previous cycle) to calculate the a-axis flux differential value Φa' and the b-axis flux differential value Φb'.

[0127] After steps S16 and S24, control circuit 100 executes step S25. In step S25, magnetic flux estimation unit 130 integrates the a-axis magnetic flux differential value Φa' and the b-axis magnetic flux differential value Φb', respectively, as shown in block 138, to calculate the a-axis magnetic flux estimated value Φa and the b-axis magnetic flux estimated value Φb. This completes the magnetic flux estimation process in step S04.

[0128] [Effects of this embodiment]

[0129] As described above, the control device 1 includes: a power conversion circuit 10 that supplies drive power to the motor 3; a magnetic flux estimating unit 130 that estimates the primary magnetic flux generated by the motor 3 due to the supply of drive power; and a voltage command generating unit 160 (control unit) that controls the power conversion circuit 10 based on the estimation result of the primary magnetic flux obtained by the magnetic flux estimating unit 130. The magnetic flux estimating unit 130 performs the following estimations: a first estimation, when the operating speed of the motor 3 is less than a predetermined level, estimating the primary magnetic flux based on the output current from the power conversion circuit 10 to the motor 3 and the inductance of the motor 3; and a second estimation, when the operating speed is greater than a predetermined level, estimating the magnetic flux differential value based on the output voltage from the power conversion circuit 10 to the motor 3. The primary magnetic flux is estimated by integrating the magnetic flux differential value using the estimation result of the primary magnetic flux obtained by the first estimation as an initial value.

[0130] The first estimation based on the output current and inductance allows for highly accurate estimation of the primary magnetic flux. However, the estimation result obtained by the first estimation is less robust to fluctuations in inductance caused by magnetic flux saturation in motor 3. Furthermore, the higher the operating speed of motor 3, the more susceptible the estimation result obtained by the first estimation is to fluctuations in inductance. On the other hand, the second estimation method, which estimates the magnetic flux differential value based on the output voltage and integrates the magnetic flux differential value to estimate the primary magnetic flux, minimizes the dependence of the primary magnetic flux estimation on inductance and therefore exhibits high robustness to fluctuations in inductance.

[0131] However, as the operating speed of motor 3 decreases and the output voltage accuracy of power conversion circuit 10 decreases, the accuracy of the magnetic flux differential value estimation decreases. Therefore, for example, in the low-speed range immediately after motor 3 startup, the estimated error in the magnetic flux differential value accumulates through integration, and this accumulated error persists even after the magnetic flux differential value estimation accuracy reaches a sufficiently high high-speed range. Consequently, even with secondary estimation alone, it is difficult to estimate the primary magnetic flux with high accuracy.

[0132] In this control device 1, when the operating speed of the motor 3 is less than a predetermined level, a first estimation is performed for the low-speed range. When the operating speed of the motor 3 is greater than the predetermined level, a second estimation is performed for the high-speed range. Furthermore, in the second estimation, the magnetic flux differential value is integrated using the primary magnetic flux estimation result obtained in the first estimation as the initial value. This reduces the influence of the magnetic flux differential value estimation error in the low-speed range on the high-speed range estimation result. This effectively improves the reliability of the control of the power conversion circuit 10 based on the primary magnetic flux.

[0133] Alternatively, magnetic flux estimation unit 130 may calculate the magnetic flux differential value based on the output voltage in the first estimation, correct the magnetic flux differential value based on the output current and inductance, and integrate the corrected magnetic flux differential value to calculate the primary magnetic flux. In this case, the first estimation can also be based on a voltage model method that calculates the primary magnetic flux by integrating the magnetic flux differential value based on the output voltage, and correct this value based on the output current and inductance, thereby smoothly transitioning from the first estimation to the second estimation and vice versa.

[0134] The magnetic flux estimating unit 130 may reduce the correction of the magnetic flux differential value based on the output current and inductance in the first estimation as the operating speed approaches a predetermined level. In this case, the transition from the first estimation to the second estimation can be performed more smoothly.

[0135] Alternatively, magnetic flux estimation unit 130 may repeatedly perform the first estimation. In each first estimation, the magnetic flux differential value is calculated based on the output voltage, a reference estimation is performed to estimate the primary magnetic flux based on the output current and inductance, a correction value is calculated based on the deviation between the primary magnetic flux estimated by the previous first estimation and the primary magnetic flux estimated by the reference estimation, and the magnetic flux differential value is corrected based on the correction value. In this case, the magnetic flux differential value based on the output current and inductance can be easily and accurately corrected.

[0136] The magnetic flux estimation unit 130 may stop correcting the magnetic flux differential value based on the output current and the inductance during the second estimation. In this case, the robustness of the primary magnetic flux estimation result can be further improved.

[0137] The magnetic flux estimation unit 130 may remove a steady-state component that does not vary with the operation of the motor 3 from the primary magnetic flux estimation result. In this case, it is possible to further achieve a balance between the accuracy and robustness of the primary magnetic flux estimation result.

[0138] The magnetic flux estimating unit 130 may stop removing the steady-state component during at least a portion of the first estimation period. In this case, the calculation load can be reduced.

[0139] Alternatively, the magnetic flux estimation unit 130 may perform low-pass filtering on the primary magnetic flux estimation result during the removal of the steady-state component and remove the filtered primary magnetic flux estimation result from the pre-filtered primary magnetic flux estimation result. In this case, the steady-state component can be easily removed.

[0140] Alternatively, the control device 1 may further include an electromagnetic force estimating unit 150 that estimates the electromagnetic force of the motor 3 based on the estimated result of the primary magnetic flux and the output current, and the voltage command generating unit 160 controls the power conversion circuit 10 based on the deviation between the target magnetic flux and the estimated result of the primary magnetic flux and the deviation between the target electromagnetic force and the estimated result of the electromagnetic force. In this case, the estimated result of the primary magnetic flux can be effectively utilized for electromagnetic force control.

[0141] The control device 1 may further include a magnetic flux command generating unit 120 that calculates a target magnetic flux based on the target electromagnetic force and the inductance. In this case, the electromagnetic force can be easily and appropriately controlled.

[0142] As mentioned above, although embodiment was demonstrated, this disclosure is not necessarily limited to the said embodiment, Various changes are possible within the range which does not deviate from the summary.

[0143] Description of Reference Numerals

[0144] 1…Control device

[0145] 3…Electric motor

[0146] 10…Power conversion circuit

[0147] 100…Control circuit (magnetic flux estimation device)

[0148] 120…Magnetic flux command generation unit

[0149] 130…Magnetic flux estimation unit

[0150] 150…Electromagnetic force estimation unit

[0151] 160 ...voltage command generating unit (control unit)

Claims

1. A control device comprising: a power conversion circuit for supplying driving power to the electric motor; a magnetic flux estimating unit that estimates a primary magnetic flux generated by the motor in response to the supply of the drive power; and a control unit that controls the power conversion circuit based on the estimation result of the primary magnetic flux obtained by the magnetic flux estimation unit, The magnetic flux estimation unit performs the following estimation: a first estimating method of estimating the primary magnetic flux based on an output current from the power conversion circuit to the motor and an inductance of the motor when an operating speed of the motor is lower than a predetermined level; and In the second estimation, when the movement speed is greater than a specified level, the magnetic flux differential value is estimated based on the output voltage from the power conversion circuit to the motor, the estimation result of the primary magnetic flux obtained by the first estimation is used as the initial value, and the magnetic flux differential value is integrated to estimate the primary magnetic flux.

2. The control device according to claim 1, wherein: The magnetic flux estimating unit calculates the magnetic flux differential value based on the output voltage in the first estimation, corrects the magnetic flux differential value based on the output current and the inductance, and integrates the corrected magnetic flux differential value to calculate the primary magnetic flux.

3. The control device according to claim 2, wherein: The magnetic flux estimating unit reduces correction of the magnetic flux differential value based on the output current and the inductance in the first estimation as the operating speed approaches a predetermined level.

4. The control device according to claim 2 or 3, wherein: The magnetic flux estimation unit repeatedly performs the first estimation, In each first inference, The magnetic flux differential value is calculated based on the output voltage, performing a reference estimation of the primary magnetic flux based on the output current and the inductance, calculating a correction value based on a deviation between an estimation result of the primary magnetic flux obtained by the previous first estimation and an estimation result of the primary magnetic flux obtained by the reference estimation, The magnetic flux differential value is corrected based on the correction value.

5. The control device according to any one of claims 1 to 3, wherein: The magnetic flux estimating unit stops correction of the magnetic flux differential value based on the output current and the inductance during the second estimation.

6. The control device according to any one of claims 1 to 3, wherein: The magnetic flux estimation unit removes a steady-state component that does not vary according to the operation of the electric motor from the estimation result of the primary magnetic flux.

7. The control device according to claim 6, wherein: The magnetic flux estimating unit stops removing the steady-state component during at least a portion of a period in which the first estimation is performed.

8. The control device according to claim 7, wherein: The magnetic flux estimating unit performs low-pass filtering on the estimation result of the primary magnetic flux during the removal of the steady-state component, and removes the estimation result of the primary magnetic flux after filtering from the estimation result of the primary magnetic flux before filtering.

9. The control device according to claim 8, wherein: further comprising an electromagnetic force estimating unit for estimating the electromagnetic force of the motor based on the estimation result of the primary magnetic flux and the output current, The control unit controls the power conversion circuit based on a deviation between a target magnetic flux and an estimated result of the primary magnetic flux and a deviation between a target electromagnetic force and an estimated result of the electromagnetic force.

10. The control device according to claim 9, wherein: The control device further includes a magnetic flux command generating unit that calculates the target magnetic flux based on the target electromagnetic force and the inductance.

11. A magnetic flux estimating device, the magnetic flux estimating device performing the following estimation: a first estimation of estimating a primary magnetic flux generated by the motor based on an output current from a power conversion circuit to the motor and an inductance of the motor when an operating speed of the motor is lower than a predetermined level; and In the second estimation, when the movement speed is greater than a specified level, the magnetic flux differential value is estimated based on the output voltage from the power conversion circuit to the motor, the estimation result of the primary magnetic flux obtained by the first estimation is used as the initial value, and the magnetic flux differential value is integrated to estimate the primary magnetic flux.

12. A magnetic flux estimation method, comprising: a first estimation of estimating a primary magnetic flux generated by the motor based on an output current from a power conversion circuit to the motor and an inductance of the motor when an operating speed of the motor is less than a predetermined level; and In the second estimation, when the movement speed is greater than a specified level, the magnetic flux differential value is estimated based on the output voltage from the power conversion circuit to the motor, the estimation result of the primary magnetic flux obtained by the first estimation is used as the initial value, and the magnetic flux differential value is integrated to estimate the primary magnetic flux.

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