Power conversion device

Abstract

The invention provides a power conversion device capable of limiting both power and current and realizing highly stable control characteristics. A power conversion device (100) is provided with: a permanent magnet motor (1); a power converter 2 that supplies power to the permanent magnet motor 1; and a speed command correction calculation unit (11, 11a, 11b, 11c, 11d) that corrects the speed command value ([omega] r *) on the basis of the speed information ([omega] rc), the torque command value ([tau] *), and the primary current (ic). The speed command correction calculation unit (11, 11a, 11b, 11c, 11d) calculates a limit value of power so as to limit the current value of the permanent magnet motor (1) to a predetermined limit value (imax *) or less when a load torque greater than the torque value of the permanent magnet motor (1) that varies with the DC voltage of the power converter (2) is applied. And corrects the speed command value [omega] r * so that the power does not increase to the power limit value.

Description

Technical Field

[0001] The present invention relates to a power conversion device. Background Art

[0002] Patent Document 1 describes a control technique for achieving stable operation in a constant output range within a field weakening range.

[0003] Patent document 1 describes a motor output power calculation unit and a technology for correcting a speed command value so that the output power becomes below a specified value. This technology avoids causing overcurrent when a load torque greater than the torque value of a permanent magnet synchronous motor is applied in a constant output range of a weak magnetic range.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2006-191721 Summary of the Invention

[0007] Technical problem to be solved by the invention

[0008] Patent Document 1 aims to correct the speed command value and therefore does not mention a method for limiting the d-axis (flux axis) current command value calculated in the field weakening range or the q-axis (torque axis) output current calculated in speed control.

[0009] The technology described in Patent Document 1 limits the speed control input so that the electric power (i.e., electrical power) does not increase beyond the limit value. However, if a large load torque is applied during the constant output range of the field weakening range, the primary current may become an overcurrent. If the primary current exceeds the overcurrent, the machine may become inoperable.

[0010] An object of the present invention is to provide a power conversion device (ie, a power conversion device) that limits both electric power and current and achieves highly stable control characteristics.

[0011] Technical means for solving technical problems

[0012] In order to achieve the above-mentioned object, the present invention is configured as follows.

[0013] A power conversion device comprising: a permanent magnet motor; a power converter for supplying power to the permanent magnet motor; and a speed command correction calculation unit for correcting the speed command value based on speed information, a torque command value, and a primary current, wherein the speed command correction calculation unit calculates a limit value for the power so that, when a load torque greater than a torque value of the permanent magnet motor that varies with a DC voltage of the power converter is applied, the current value of the permanent magnet motor is limited to below a prescribed limit value, and the speed command value is corrected so that the power does not increase to the limit value for the power.

[0014] Effects of the Invention

[0015] According to the present invention, it is possible to provide a power conversion device that limits both electric power and current and realizes highly stable control characteristics.

[0016] That is, according to the present invention, a power conversion device can be provided that will not cause overcurrent and can operate stably when a load torque greater than the torque value of the permanent magnet motor that changes due to the DC voltage of the power converter is applied in a constant output interval of the weak magnetic field (weakening magnetic field) interval. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic structural diagram of the power conversion device of Example 1.

[0018] Figure 2 This is a structural diagram of the speed instruction correction calculation unit of the first embodiment.

[0019] Figure 3 This is a diagram showing control characteristics when the first embodiment is not used.

[0020] Figure 4 This is a diagram showing control characteristics when the first embodiment is used.

[0021] Figure 5 This is an explanatory diagram of the verification method when the first embodiment is adopted.

[0022] Figure 6 This is a schematic structural diagram of a power conversion device according to the second embodiment.

[0023] Figure 7 This is a structural diagram of the speed instruction correction calculation unit of the second embodiment.

[0024] Figure 8 This is a structural diagram of a power conversion device according to a third embodiment.

[0025] Figure 9 This is a structural diagram of the speed instruction correction calculation unit of Example 3.

[0026] Figure 10 This is a structural diagram of a power conversion device according to a fourth embodiment.

[0027] Figure 11 This is a structural diagram of the speed instruction correction calculation unit of the fourth embodiment.

[0028] Figure 12 This is a structural diagram of the power conversion device of Example 5.

[0029] Figure 13 This is a structural diagram of the speed instruction correction calculation unit of Example 5.

[0030] Figure 14 It is a structural diagram of the power conversion device of Example 6.

[0031] Figure 15 It is a structural diagram of the power conversion device of Example 7.

[0032] Figure 16 It is a structural diagram of the power conversion device of Example 8.

[0033] Figure 17 This is a structural diagram of the power conversion device of Example 9.

[0034] Figure 18 This is a structural diagram of the speed instruction correction calculation unit of Example 9. DETAILED DESCRIPTION

[0035] Hereinafter, this embodiment will be described in detail using the accompanying drawings. In addition, the same reference numerals are given to common structures in the various figures. In addition, the various embodiments described below are not limited to the illustrated examples.

[0036] The embodiments are merely examples for explaining the present invention, and are appropriately omitted or simplified for clarity of explanation. The present invention can also be implemented in various other forms.

[0037] Unless otherwise specified, each component may be single or plural. The positions, sizes, shapes, and ranges of components shown in the drawings may not represent their actual positions, sizes, shapes, and ranges, etc., in order to facilitate understanding of the invention. Therefore, the present invention is not necessarily limited to the positions, sizes, shapes, and ranges shown in the drawings.

[0038] Example

[0039] <Example 1>

[0040] Figure 1 This is a schematic configuration diagram of the power conversion device 100 according to the first embodiment.

[0041] Figure 1In FIG. 1 , a permanent magnet motor (permanent magnet motor) 1 outputs a motor torque obtained by synthesizing a torque component based on the magnetic flux of a permanent magnet and a torque component based on the inductance of an armature winding.

[0042] The output of the power converter 2 is the same as the voltage command value v of the three-phase AC u * 、v v * 、v w * The output voltage and frequency of the permanent magnet motor 1 can be changed by adjusting the voltage value proportional to the output voltage. The controller (microcomputer, etc.) of the power converter 2 sets the power limit value P max * , the primary current limit value i max * , the limit value of computing power P max ** .

[0043] The DC power supply 3 supplies a DC voltage to the power converter 2 .

[0044] The current detector 4 outputs the three-phase AC current i of the permanent magnet motor 1 u 、i v 、i w The detection value is i uc 、i vc 、i wc In addition, the current detector 4 can also detect the AC current of two phases, for example, the u phase and the w phase, among the three phases of the permanent magnet motor 1. u +i v +i w =0) Press i v =-(i u +i w )Calculate the AC current of phase v.

[0045] The position detector 5 has a resolution (resolving power) for detecting the position of the permanent magnet motor 1 with high accuracy, and is used to calculate the speed of the permanent magnet motor 1 .

[0046] The coordinate conversion unit 6 is based on the three-phase AC current i u 、i v 、i w The detection value i uc 、i vc 、i wc and phase detection value θ dc Outputs the d-axis and q-axis current detection values ​​i input to the permanent magnet motor 1 dc 、i qc .

[0047] The speed control calculation unit 7 calculates the speed command value ω based on the speed command value ω. r * Correction value Δω of the speed command value r * The new speed command value ω is obtained by adding r ** and speed detection value (or speed estimation value) w rc Calculate and output the q-axis current command value i q * In addition, the speed detection value (or speed command value) w rc Defined as speed information.

[0048] The vector control calculation unit 8 outputs the current command value i based on the d-axis and q-axis. d * 、i q * , current detection value i dc 、i qc , speed detection value ω rc The voltage command values ​​v of the d-axis and q-axis obtained by calculating the circuit parameters of the permanent magnet motor 1 are dc ** 、v qc ** , and as the voltage command value V * and DC voltage value E dc The modulation rate K is 1 / 2 of the h * .

[0049] The field weakening control calculation unit 9 is based on the modulation rate K of the voltage command value. h * Output d-axis current command value i d * .

[0050] The frequency and phase detection calculation unit 10 calculates the position detection value q detected by the position detector 5. d Converted into a phase detection value θ that changes between 0 and 2π in one rotation of the mechanical angle of the permanent magnet motor 1 dc In addition, based on the position detection value q dc Calculate the speed detection value w of the change rc .

[0051] The speed instruction correction calculation unit 11 is based on the current instructions i of the d-axis and q-axis. d * 、i q * , and torque command value τ * and speed detection value w rc , output speed command value correction value Δωr * .

[0052] The coordinate conversion unit 12 is based on d c axis and q c Axis voltage command value v dc ** 、v qc ** , and phase detection value θ dc , output three-phase AC voltage command value v u * 、v v * 、v w * .

[0053] First, a basic operation of the vector control method in the case of using the speed command correction calculation unit 11 that is a feature of the first embodiment will be described.

[0054] The frequency and phase detection calculation unit 10 imports the incremental or absolute encoder signal and generates a phase detection value q where the phase value changes from 0 to 2π in one mechanical angle rotation. dc Use this q dc , calculate the speed detection value ω according to formula (1) rc .

[0055] [Number 1]

[0056]

[0057] The speed control calculation unit 6 makes the speed detection value ω rc Follow the new speed command value ω described later r ** By proportional control and integral control, the torque command value τ is calculated according to formula (2). * .

[0058] [Number 2]

[0059]

[0060] In formula (2), K sp is the proportional gain of speed control, K si is the integral gain of speed control.

[0061] In addition, the torque command value τ is used * and the d-axis current command value i d * And the electrical parameters of the permanent magnet motor 1 (L d , L q , K e) Calculate the q-axis current command value i by following formula (3): q * .

[0062] [Number 3]

[0063]

[0064] In formula (3), L d * is the inductance setting value of the d-axis, L q * is the inductance setting value of the q-axis, K e * is the set value of the inductive voltage coefficient, P m is the extreme logarithm.

[0065] The field weakening control calculation unit 9 makes the modulation rate K h Does not exceed the modulation rate limit K h * By means of integral control, the current command value i of the d-axis is calculated as follows (4). d * .

[0066] [Number 4]

[0067]

[0068] In formula (4), K p_id is the proportional gain of field weakening control, K i_id is the integral gain of field weakening control.

[0069] The vector control calculation unit 8 first uses the set value R of the winding resistance as the electrical parameter of the permanent magnet motor 1. * , d-axis inductance setting value L d * , q-axis inductance setting value L q * , setting value of induction voltage coefficient K e * d c axis and q c Axis current command value i d * 、i q * And the speed detection value ω rc , output d according to formula (5) c axis and q c Axis voltage reference value v dc * 、v qc * .

[0070] [Number 5]

[0071]

[0072] In formula (5), T acr is the response time constant of the current control.

[0073] Secondly, the current detection value i of each component is dc 、i qc Follow d c axis and q c Axis current command value i d * 、i q * By proportional control and integral control, d is calculated according to formula (6). c axis and q c Axis voltage correction value Δv dc , Δv qc .

[0074] [Number 6]

[0075]

[0076] In formula (6), K pd It is d c Proportional gain of axis current control, K id It is d c Integral gain of axis current control, K pq It's q c Proportional gain of axis current control, K iq It is q c Integral gain of the axis current control.

[0077] Then, calculate d according to the following formula (7): c axis and q c Axis voltage command value v dc ** 、v qc ** .

[0078] [Number 7]

[0079]

[0080] exist Figure 2 2 shows the configuration of the speed instruction correction calculation unit 11 which is a feature of the first embodiment of the present invention.

[0081] Reference numeral 11_1 is a limit value i for controlling the current of the permanent magnet motor 1 or the power converter 2 to be below an overcurrent value. max Setting part. So that the current limit value imax At the overcurrent level value i of the power converter 2 oc_lvl The following method sets the limit value i according to the following formula (8): max .

[0082] [Number 8]

[0083] i max * <i oc_lvl …(8)

[0084] The primary current calculation unit 11_2 uses the current command values ​​i of the d-axis and q-axis. d * 、i q * , calculate the primary current command value i according to formula (9) c * .

[0085] [Number 9]

[0086]

[0087] You can also use the current command value i d * 、i q * The d-axis and q-axis current detection values ​​i dc 、i qc To calculate the detection value of the primary current i c , instead of the primary current command value i c * Used locally.

[0088] Reference numeral 11_3 is a limit value P of the electric power of the permanent magnet motor 1 or the electric power converter 2. max The setting unit may set a value that enables the permanent magnet motor 1 to operate.

[0089] The power calculation unit 11_4 uses the speed detection value ω rc and torque command value τ * , calculate the power calculation value P according to the following formula (10).

[0090] [Number 10]

[0091] P=ωrc·τ * …(10)

[0092] Reference numeral 11_5 denotes a power / current control calculation unit. The current limit value i max * , the primary current command value i c * , Power limit value P max* The power calculation value P is input to the power / current control calculation unit, and the speed command value correction value Δω is calculated according to the following procedure: r * .

[0093] (1) To make the primary current command value i c * The current limit value i max * The following method uses proportional / integral calculation to calculate the power correction value ΔP according to the following formula (11): max .

[0094] [Number 11]

[0095]

[0096] In formula (11), K p_acr is the proportional gain of the primary current command value control, K i_acr It is the integral gain of the primary current command value control.

[0097] (2) Power usage limit value P max * and the power correction value ΔP max Calculate the new power limit value P according to the following formula (12): max ** .

[0098] [Number 12]

[0099] P max ** =P max * +ΔP max …(12)

[0100] (3) The power calculation value P is set to the new power limit value P. max ** The correction value Δω of the speed command value is calculated by proportional / integral operation according to formula (13) as follows: r * .

[0101] [Number 13]

[0102]

[0103] In formula (13), K p_Δw is the proportional gain of the power limit control, K i_Δw This is the integral gain of the electric power limit value control.

[0104] (4) Use speed command value ω r* and the correction value Δω of the speed command value r * , calculate the new speed command value ω according to formula (14) r ** .

[0105] [Number 14]

[0106] ω r ** =ω r * +Δω r * …(14)

[0107] Next, the principle by which the present invention can operate stably in the constant output range of the field weakening range will be described.

[0108] exist Figure 3 , which does not use the speed command correction calculation unit 11 of the present invention and applies a large load torque, shows the control characteristics. This is a simulation result in which a load torque is applied while increasing the speed command value from zero to the base speed.

[0109] Figure 3 The upper part shows the speed detection value ω of the permanent magnet motor 1 rc The lower part shows the detected value i of the primary current obtained by the calculation of the following formula (15): c .

[0110] [Number 15]

[0111]

[0112] exist Figure 3 From time A to B, the speed command value ω r * The speed increases from zero to the base speed, and a large load torque is applied from time C to D. At time E, the power calculation value P becomes the power limit value P. max * The following method makes the speed detection value ω rc deceleration, but at time F the primary current detection value i c Increase to overcurrent level value i oc_lvl , and therefore became inoperable thereafter.

[0113] exist Figure 4 2 shows the control characteristics of the speed instruction correction calculation unit 11 using the present invention. Figure 4 The control characteristics shown are with Figure 3 The same simulation results are shown in the example.

[0114] Figure 4In the example, for the primary current command value i max * Set the overcurrent level value i oc_lvl A lower value, at time F the new power command value P max ** Power command value P max * Correction, the result is that the detection value of the primary current i c You can also use i max * Control is performed so that overcurrent does not occur and stable operation is possible.

[0115] Here, use Figure 5 A verification method in an example in which the first embodiment is employed will be described.

[0116] Figure 5 In the embodiment, a current detector 21 is mounted on a power conversion device 20 that drives a permanent magnet motor 1 , and an encoder 22 is mounted on the shaft of the permanent magnet motor 1 .

[0117] The speed command value ω given to the controller (not shown) of the power converter 2 is r * The base speed is set, and a large torque is applied to the permanent magnet motor 1 .

[0118] The speed and vector current component calculation unit 23 receives the three-phase AC current detection value (i uc 、i vc 、i wc ) and the output of the encoder 22, i.e., the position detection value θ, the detection value i of the vector current component is calculated by the following formula (16): dcc 、i qcc , calculate the detected value of the primary current i according to formula (17) cc , calculate the speed detection value ω according to formula (18) rcc .

[0119] [Number 16]

[0120]

[0121] [Number 17]

[0122]

[0123] [Number 18]

[0124]

[0125] Furthermore, the electrical parameters (K e * , L d* , L q * ) and the detected value i of the vector current component dcc 、i qcc , calculate the torque estimated value t^ according to formula (19).

[0126] [Number 19]

[0127]

[0128] Finally, use the speed detection value ω rcc The power estimated value P^ is calculated using the torque estimated value t^ according to the following formula (20).

[0129] [Number 20]

[0130] P^=ω rcc ·τ^…(20)

[0131] By observing the action waveforms obtained by using equations (16) to (20), it is confirmed that Figure 4 The operation waveforms shown can verify the use of Example 1 of the present invention.

[0132] Because embodiment 1 of the present invention adopts the structure described above, it is possible to provide a power conversion device 100 that can operate stably without causing overcurrent when a load torque greater than the torque value of the permanent magnet motor 1 that varies due to the DC voltage of the power converter 2 is applied in the constant output range of the weak magnetic range.

[0133] <Example 2>

[0134] Next, Example 2 of the present invention will be described.

[0135] Figure 6 It is a schematic configuration diagram of a power conversion device 100 according to the second embodiment.

[0136] The above embodiment 1 adopts the method of adjusting the speed instruction correction calculation unit 11 in addition to the input current instruction i d * 、i q * In addition, the speed detection value w is also input rc and torque command value τ * However, in the second embodiment, the input speed detection value w is replaced by rc and torque command value τ * The input DC voltage value E DC and DC current value I DC way.

[0137] Figure 6The reference numerals 1, 2, 5 to 10, and 12 in the figure represent Figure 1 Reference numeral 13 is a detection unit for detecting the DC current I DC The current detector, reference numeral 14, is a current detector for detecting the DC voltage E DC voltage detector.

[0138] Assume that the current detection value of DC current is I DC , assume that the voltage detection value of DC voltage is E DC .

[0139] exist Figure 7 2 shows the configuration of the speed instruction correction calculation unit 11 a in the second embodiment. Figure 7 The reference numerals 11a_1, 11a_2, 11a_3, and 11a_5 in FIG. Figure 2 The same components are denoted by the reference numerals 11_1, 11_2, 11_3, and 11_5.

[0140] Reference numeral 11a_4 is a power calculation unit, which uses the current detection value I of the DC current. DCc , DC voltage detection value E DCc , calculate the power calculation value P^^ according to the following formula (21).

[0141] [Number 21]

[0142] P^^=E DCc I DCc …(twenty one)

[0143] The power / current control calculation unit 11a_5 rewrites the power calculation value P^^ into the power calculation value P and calculates the correction value Δω of the speed command value. r * .

[0144] As in the power / current control calculation unit 11a_5 in the second embodiment, even if the speed detection value w is replaced rc and torque command value τ * Ground is used as the DC voltage value E DC , DC current value I DC The DC side power calculation value can also achieve stable control characteristics.

[0145] The same effects as those of the first embodiment can also be obtained in the second embodiment.

[0146] In addition, existing devices can be used as the current detector 13 and the voltage detector 14 .

[0147] <Example 3>

[0148] Next, Example 3 of the present invention will be described.

[0149] Figure 8 It is a structural diagram of a power conversion device 100 according to the third embodiment.

[0150] The above embodiment 1 adopts the method of adjusting the speed instruction correction calculation unit 11 in addition to the input current instruction i d * 、i q * In addition, input the speed detection value w rc and torque command value τ * However, in Example 3, the speed detection value w is replaced rc and torque command value τ * Ground, input voltage command value v of d-axis and q-axis dc ** 、v qc ** way.

[0151] Figure 8 Reference numerals 1 to 10 and 12 in the figure represent Figure 1 Same components.

[0152] exist Figure 9 2 shows the configuration of the speed instruction correction calculation unit 11 b in the third embodiment. Figure 9 Reference numerals 11b_1, 11b_2, 11b_3, and 11b_5 are the same as those in FIG. Figure 2 Reference numerals 11_1, 11_2, 11_3, and 11_5 are the same components. Reference numeral 11b_4 is a power calculation unit, which uses the current command values ​​i of the d-axis and q-axis. d * 、i q * and voltage command value v dc ** 、v qc ** , the set value R of the resistance as the electrical parameter of the permanent magnet motor 1 * , calculate the power calculation value P^^^ according to the following formula (22).

[0153] [Number 22]

[0154] P^^^=v dc ** i d * +v qc ** i q * -R * (i d * ^ 2 +i q* ^ 2 )…(twenty two)

[0155] The power / current control calculation unit 11b_5 may rewrite the power calculation value P^^^ into the power calculation value P and calculate the correction value Δω of the speed command value. r * .

[0156] According to the third embodiment, even when the electric power calculation value of the vector control is used, a stable control characteristic can be achieved similarly to the first embodiment.

[0157] Compared with Embodiments 1 and 2, Embodiment 3 has the effect of being able to replace a portion constituted by software.

[0158] <Example 4>

[0159] Next, Example 4 of the present invention will be described.

[0160] Figure 10 It is a structural diagram of a power conversion device 100 according to a fourth embodiment.

[0161] In this embodiment 4, a new speed command value ω is used. r ** (Speed ​​command value after correction) A method of correcting the parameter (limit value of electric power) set in the speed command correction calculation unit 11c.

[0162] Figure 10 Reference numerals 1 to 10 and 12 in the figure represent Figure 1 The same components. Figure 11 2 shows the configuration of the speed instruction correction calculation unit 11 c. Figure 11 The reference numerals 11c_1, 11c_2, 11b_4, and 11b_5 in FIG. Figure 2 Reference numerals 11_1, 11_2, 11_4, and 11_5 are the same components. Reference numeral 11c_3 is the power limit value P max * In the first embodiment, the power limit value P max * With the new speed command value ω r ** The size of is irrelevant and is a fixed value, but it can also be adjusted according to the speed command value ω r ** Rewrite the power limit value P max * Alternatively, it can be based on the speed command value ω r ** Output power limit value P max * Reference table.

[0163] The fourth embodiment can obtain the same effect as the first embodiment, and optimizes the power limit value P according to the operating state. max * , and the following effect is obtained: the detection value of the primary current i c The current value does not become unnecessarily large, and the current value becomes small, thereby achieving highly efficient and stable control characteristics.

[0164] <Example 5>

[0165] Next, Example 5 of the present invention will be described.

[0166] Figure 12 It is a structural diagram of a power conversion device 100 according to the fifth embodiment.

[0167] In the above-mentioned embodiments 1 to 4, the current command values ​​i of the d-axis and q-axis of the rotating coordinate system are input to the speed command correction calculation unit 11. d * 、i q * However, in the fifth embodiment, the detection value i of the primary current in the stationary coordinate system is input. c1 (A method of calculating a current value based on a detected value of a current input to the permanent magnet motor 1).

[0168] Figure 12 Reference numerals 1 to 5, 7 to 10, and 12 denote Figure 1 The same components. Reference numeral 6a is the operation d c axis and q c Axis current detection value i dc 、i qc And the detection value of the primary current i c1 The coordinate conversion unit 6a calculates the detected value i of the primary current according to the following formula (23): c1 .

[0169] [Number 23]

[0170]

[0171] exist Figure 13 2 shows the configuration of the speed instruction correction calculation unit 11d. Figure 13 The reference numerals 11d_1, 11d_3, 11d_4, and 11d_5 in FIG. Figure 2 The same components as those in the reference numerals 11_1, 11_3, 11_4, and 11_5 are shown in FIG. c1 Rewritten as detection value i c In step 11d_5, the correction value Δω of the speed command value is calculated.r * .

[0172] The fifth embodiment can obtain the same effects as those of the first embodiment, and can omit the primary current calculation unit 11_2 in the first embodiment, thereby achieving a stable control characteristic with less control calculation.

[0173] In the above manner, the speed instruction correction calculation unit 11d of the fifth embodiment omits the primary current calculation unit 11_2 of the speed instruction correction calculation unit 11 of the first embodiment, and inputs the detected value i of the primary current. c1 However, it is also possible to omit the speed instruction correction calculation units 11a_2, 11b_2, 11c_2 of the embodiments 2 to 4 and the detection value i of the input primary current. c1 structure.

[0174] <Example 6>

[0175] Next, Example 6 of the present invention will be described.

[0176] Figure 14 It is a structural diagram of the power conversion device 100 according to the sixth embodiment.

[0177] While the first embodiment adopts a method in which the position detector 5 is mounted on the permanent magnet motor 1 , the sixth embodiment adopts a method in which the position detector 5 is omitted.

[0178] Figure 14 Reference numerals 1 to 4, 6 to 12 in the figure represent Figure 1 The same components are provided. The reference numeral 15 is input to the d of the power converter 2. c axis and q c Axis voltage command value v dc ** 、v qc ** , and the current detection value i dc 、i qc , based on these values, the speed estimation value ω is output rc , and the estimated position value θ dc .

[0179] The frequency and phase estimation subtraction unit 15 estimates the dq axis based on the magnetic flux as the reference of the rotation coordinate system of the permanent magnet motor 1 and the dq axis based on the control according to the following formula (24). c -q c The phase difference between the two axes is the phase error Δθ.

[0180] [Number 24]

[0181]

[0182] To follow the command value Δθ c * (=0), the speed estimation value ω of the permanent magnet motor 1 is calculated by P (proportional) + I (integral) control according to the formula (25). rc , the phase estimation value θ is calculated by I (integral) control according to formula (26) dc .

[0183] [Number 25]

[0184]

[0185] [Number 26]

[0186]

[0187] In formula (25), K p_pll is the proportional gain of the PLL control, K i_pll is the integral gain of the PLL control.

[0188] The sixth embodiment can obtain the same effects as those of the first embodiment, and can also omit the position detector 5 in the first embodiment, thereby achieving highly stable control characteristics at low cost.

[0189] Example 6 can also be applied to Examples 1 to 5.

[0190] <Example 7>

[0191] Next, Example 7 of the present invention will be described.

[0192] Figure 15 It is a structural diagram of the power conversion device 100 according to the seventh embodiment.

[0193] In the first to sixth embodiments, the controller (microcomputer, etc.) of the power converter 2 sets the power limit value P max * , the primary current limit value i max * , the limit value of computing power P max ** However, in the seventh embodiment, the controlled state quantity is fed back to the upper IOT controller 16, and machine learning such as deep learning is performed to reset the power limit value P of the speed instruction correction calculation unit 11d. max * , the primary current limit value i max * way.

[0194] Figure 15 Reference numerals 1 to 12 in the figure represent Figure 1 Same components.

[0195] Figure 15 In the example, the voltage command value v for the power converter 2 is dc * 、v dc * and the detected value i of the current input to the permanent magnet motor 1 dc 、i qc , and the estimated values ​​of phase error and speed are fed back to the IOT controller 16 as the upper device and analyzed (parsed), and the parameters of the prescribed value of the power limit value or the prescribed value of the current are automatically corrected. That is, the power conversion device 100 includes the IOT controller 16, which sends the voltage command value v to the power converter 2. dc * 、v qc * and the current detection value i input to the permanent magnet motor 1 dc 、i qc , and the phase error and speed estimation value of the permanent magnet motor 1 are fed back and analyzed, and the parameters related to the power limit value or the parameters related to the current are automatically corrected.

[0196] The same effect as that of the first embodiment can also be obtained in the seventh embodiment. In the seventh embodiment, the speed instruction correction calculation unit 11d is reset to the power limit value P by performing feedback to the IOT controller 16 and performing machine learning such as deep learning. max * , the primary current limit value i max * , so more stable and efficient control characteristics can be achieved without adjustment.

[0197] In addition, Example 7 can also be applied to Examples 2 to 6.

[0198] <Example 8>

[0199] Next, Example 8 of the present invention will be described.

[0200] Figure 16 It is a structural diagram of a power conversion device 100 according to the eighth embodiment.

[0201] Example 8 applies the present invention to a permanent magnet motor drive system. Figure 16 Including Figure 1 Reference numerals 1 to 12 indicate the components shown.

[0202] and Figure 1 The permanent magnet motor 1 having the same components as shown is driven by a power conversion unit 20. The power conversion unit 20 is a microcomputer. Figure 1 The components denoted by 6 to 12 are software 20a. Figure 1 The components denoted by 2 to 5 in the figure are realized as hardware.

[0203] In addition, the "power limit value P" of the software 20a can be set and changed by a higher-level device such as a digital operator 20b, a personal computer 32, a tablet computer 33, or a smartphone 34. max * 30. The primary current limit value i max * 31. Parameters regarding the power limit value or the current of the permanent magnet motor 1 are set for the power conversion unit 20. The parameters set for the power conversion unit 20 can be set or changed via a digital operator, a personal computer 32, a tablet computer 33, or a smartphone 34.

[0204] In addition, the "limit value of power P max * 30. The primary current limit value i max * "31 can also be set on a field bus such as a programmable logic controller, a local area network connected to a computer, or an IoT controller.

[0205] Furthermore, in the eighth embodiment, an example of application to the first embodiment is shown, but the invention can also be applied to the second to seventh embodiments.

[0206] In the first to eighth embodiments, the current command value i d * 、i q * and the current detection value i dc 、i qc Generate voltage correction value Δv dc , Δv qc , the voltage correction value Δv is dc , Δv qc The operation shown in (Equation (7)) is added to the voltage reference value of the vector control, but it can also be performed based on the current command value i d * 、i q * and the current detection value i dc 、i qc The intermediate current command value i is generated as shown in the following equation (27) used in the vector control operation. d ** 、i q ** , using the speed detection value or speed estimation value ω rc The vector control operation shown in the following equation (28) is performed with the circuit parameters of the permanent magnet motor 1.

[0207] [Number 27]

[0208]

[0209] [Number 28]

[0210]

[0211] In formula (27) and formula (28), K pd1 It is d c Proportional gain of axis current control, K id1 It is d c Integral gain of axis current control, K pq1 It is q c Proportional gain of axis current control, K iq1 It is q c Integral gain of axis current control, T d is the electrical time constant of the d-axis (L d / R), T q is the q-axis electrical time constant (L q / R).

[0212] Alternatively, the current command value i d * 、i q * and the current detection value i dc 、i qc , generate the d used in vector control operation according to formula (29) c Voltage correction value Δv of the proportional operation component of the axis d_p * d c Voltage correction value Δv of the integral operation component of the axis d_i * ,q c Voltage correction value Δv of the proportional operation component of the axis q_p * ,q c Voltage correction value Δv of the integral operation component of the axis q_i * , use the speed detection value or speed estimation value ω rc The vector control operation shown in the following equation (30) is performed based on the circuit parameters of the permanent magnet motor 1.

[0213] [Number 29]

[0214]

[0215] In formula (29), K pd2 It is d c Proportional gain of axis current control, K id2 It is dc Integral gain of axis current control, K pq2 It is q c Proportional gain of axis current control, K iq2 It is q c Integral gain of the axis current control.

[0216] [Number 30]

[0217]

[0218] Alternatively, you can use d c Axis current command value i d * and q c Axis current detection value i qc The first-order lag (first lag) signal i qctd , speed estimated value ω rc , and the circuit parameters of the permanent magnet motor 1 perform the vector control operation shown in the following equation (31).

[0219] [Number 31]

[0220]

[0221] In Embodiments 1 to 8, the switching elements constituting the power converter 2 may be Si (silicon) semiconductor elements, or wide-bandgap semiconductor elements such as SiC (silicon carbide) and GaN (gallium nitride).

[0222] The eighth embodiment can also achieve the same effects as the first embodiment. Furthermore, when the eighth embodiment is applied to an AC servo or inverter driven by the permanent magnet motor 1 , highly stable and efficient control characteristics can be achieved in vector control with or without the position detector 5 .

[0223] <Example 9>

[0224] Next, Example 9 of the present invention will be described.

[0225] Figure 17 It is a structural diagram of a power conversion device 100 according to the ninth embodiment.

[0226] Example 9 is to use the DC voltage detection value E DCc A method of correcting the parameters set in the speed instruction correction calculation unit 11e.

[0227] Figure 17 The reference numerals 1 to 10 and 12 in the figure are Figure 1 The same components as those in FIG. 1 and reference numeral 14 are components for detecting the DC voltage E. dc In addition, let the voltage detection value of the DC voltage be EDCc .

[0228] exist Figure 18 2 shows the configuration of the speed instruction correction calculation unit 11e. Figure 18 The reference numerals 11e_1, 11e_2, 11e_4, and 11e_5 in FIG. Figure 2 The same components as those 11_1, 11_2, 11_4, and 11_5 are shown in the figure. Figure 18 Reference numeral 11e_3 in FIG. 1 is the limit value P of the electric power. max * Settings section.

[0229] In Example 1, the limit value P max * The detection value E of the DC voltage DCc The value is fixed regardless of the size, but it can also be adjusted according to the detection value E DCc Correct (rewrite) the power limit value P max * Or it can be based on the detection value E DCc The output limit value P max * Reference table.

[0230] In the ninth embodiment, the same effects as those of the first embodiment can be obtained, and the power limit value P is optimized according to the operating state. max * , can achieve the following effect: the detection value of the primary current i c The current value does not become unnecessarily large, and a high-efficiency and stable control characteristic can be achieved.

[0231] Description of Reference Numerals

[0232] 1... Permanent magnet motor, 2... Power converter, 3... DC power supply, 4... Current detector, 5... Position detector, 6, 6a... Coordinate conversion unit, 7... Speed ​​control calculation unit, 8... Vector control calculation unit, 9... Field weakening control calculation unit, 10... Frequency and phase detection calculation unit, 11, 11a, 11b, 11c, 11d... Speed ​​command correction calculation unit, 12... Coordinate conversion unit, 13... DC current detector, 14... DC voltage detector, 15... Frequency and phase estimation calculation unit, 16... IOT controller, 20... Power conversion unit, 20a... Software unit for power conversion unit, 20b... Digital operator for power conversion unit, 21... Current detector, 22... Encoder, 23... Speed ​​and vector current component calculation unit, 24... Primary current detection value and power calculation value observation unit, 30... Power limit value, 31... Primary current limit value, 32... Personal computer, 33... Tablet computer, 34... Smartphone, 100... Power conversion device, i d * ...current command value of d-axis, i q * ...the command value of the q-axis current, i dc ...current command value of d-axis, i qc ...q c The command value of the shaft current, τ * ...Torque command value, ω rc ...speed detection value (or speed estimation value), ω r ...the speed of permanent magnet motor 1, ω r * ...speed command value, v dc * v dc ** v dc *** v dc **** v dc ***** ...voltage command value of the d-axis, v qc * v qc ** v qc *** v qc **** v qc ***** ...q-axis voltage command value, P, P^, P^^...power calculation value, P max * P max ** ...limit value of electricity, i max* ...limit value of the primary current instruction, i c i c1 ...Detected value of primary current.

Claims

1. A power conversion device, characterized in that: include: Permanent magnet motor; a power converter for supplying power to the permanent magnet motor; and A speed instruction correction calculation unit that corrects the speed instruction value based on the speed information, the torque instruction value, and the primary current. The speed command correction calculation unit calculates the limit value of the electric power so that when a load torque greater than the torque value of the permanent magnet motor that varies with the DC voltage of the power converter is applied, the current value of the permanent magnet motor is limited to below a prescribed limit value, and the speed command value is corrected so that the electric power does not increase to the limit value of the electric power.

2. The power conversion device according to claim 1, wherein: The speed command correction calculation unit corrects the speed command value so that the electric power calculated based on the torque command value and the speed information does not increase to the electric power limit value.

3. The power conversion device according to claim 1, wherein: The speed command correction calculation unit corrects the speed command value so that the electric power calculated based on the DC voltage value and the DC current value of the power converter does not increase to the electric power limit value.

4. The power conversion device according to claim 1, wherein: The speed command correction calculation unit corrects the speed command value so that electric power calculated based on voltage values ​​and current values ​​on dq axes of the permanent magnet motor does not increase to the electric power limit value.

5. The power conversion device according to any one of claims 2 to 4, wherein: The primary current is a current calculated based on a detected value of a current input to the permanent magnet motor.

6. The power conversion device according to any one of claims 2 to 4, wherein: The electric power limit value can be corrected using the corrected speed command value.

7. The power conversion device according to any one of claims 2 to 4, wherein: include: a position detector for detecting a position of the permanent magnet motor; and A frequency and phase detection and calculation unit calculates a speed of the permanent magnet motor based on the position of the permanent magnet motor detected by the position detector.

8. The power conversion device according to any one of claims 2 to 4, wherein: include: A frequency and phase estimation calculation unit estimates the position and speed of the permanent magnet motor based on the voltage command value and the current detection value of the power converter.

9. The power conversion device according to any one of claims 2 to 4, wherein: include: The IOT controller sets the voltage command value v for the power converter dc * The current detection value input to the permanent magnet motor, as well as the phase error and speed estimation value of the permanent magnet motor are fed back and analyzed, and the parameters related to the power limit value are automatically corrected.

10. The power conversion device according to any one of claims 2 to 4, wherein: include: a power conversion unit for setting a parameter regarding the limit value of the electric power or a parameter regarding the current of the permanent magnet motor; The parameters set for the power conversion unit can be set or changed via a digital operator, a personal computer, a tablet computer, or a smartphone.

11. The power conversion device according to claim 2, wherein: include: a voltage detector for detecting a DC voltage of the power converter, The power limit value can be corrected based on the DC voltage detected by the voltage detector.

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