Power conversion device

Abstract

This invention eliminates the need for rotary automatic adjustment, achieving high-precision control characteristics by calculating the induced voltage coefficient of the permanent magnet motor. The first electric power P is calculated based on the output voltage and output current of the permanent magnet motor. c The second electric power P is calculated based on the circuit constants, current command, output frequency, and induced voltage coefficient of the permanent magnet motor. c ^ The induced voltage coefficient is calculated so that the calculated first electric power tracks the second electric power, and the drive of the permanent magnet motor is controlled according to the induced voltage coefficient.

Description

TECHNICAL FIELD

[0001] The present application relates to a power conversion device, and particularly to estimation of an induced voltage coefficient of a drive of a permanent magnet motor. BACKGROUND

[0002] A power conversion device that performs sensorless control with high efficiency on a motor using a permanent magnet is known. For example, in Patent Literature 1, regarding high-precision control of a permanent magnet motor, a technique is disclosed that estimates an induced voltage coefficient of a permanent magnet motor based on a voltage command value, a current detection value, a circuit constant, and a frequency estimation value of an output of a power converter.

[0003] PRIOR ART DOCUMENTS

[0004] PATENT LITERATURE

[0005] Patent Literature 1: Japanese Patent Application Publication No. 2003-164188 SUMMARY

[0006] PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] The control method disclosed in Patent Literature 1 uses a voltage command value (v γ , v δ ), a current detection (i γ , i δ ), and a circuit constant (resistance R, d-axis inductance L d , q-axis inductance L q ) of a permanent magnet motor, and estimates an induced voltage coefficient Φ based on Equation (1).

[0008] [Mathematical Equation 1]

[0009]

[0010] Here, there is an influence of a voltage drop (w1L q i δ and w1L d i γ ) equivalent to inductance in Equation (1), and it is considered that a setting error of inductance L d , L q causes deterioration of estimation precision of the induced voltage coefficient.

[0011] In order to prevent this deterioration of estimation precision, it is necessary to rotate the permanent magnet motor in a no-load state and perform adjustment of the induced voltage coefficient. This adjustment is called rotational automatic tuning (A.T). This adjustment work must be performed before the permanent magnet motor is installed in a customer's mechanical device, and as a result, work time increases.

[0012] The present application provides a power conversion device that achieves a high-precision control characteristic by estimating a coefficient of induced voltage of a permanent magnet motor without a rotation-type automatic adjustment.

[0013] Technical solution for solving the problem

[0014] To solve the above problem, a preferred aspect of the present application can estimate a coefficient of induced voltage of a permanent magnet motor using active power or reactive power in actual operation of the permanent magnet motor.

[0015] A preferred embodiment of the present application discloses a power conversion device that controls a permanent magnet motor, wherein:

[0016] calculates a first electric power based on an output voltage and an output current of the permanent magnet motor,

[0017] calculates a second electric power based on a circuit constant, a current command, an output frequency, and the coefficient of induced voltage of the permanent magnet motor,

[0018] estimates the coefficient of induced voltage in such a manner that the first electric power tracks the second electric power,

[0019] controls driving of the permanent magnet motor according to the coefficient of induced voltage.

[0020] Invention effect

[0021] According to the present application, by estimating a coefficient of induced voltage of a permanent magnet motor in actual operation, a high-precision control characteristic can be achieved without adjustment of a circuit constant of the permanent magnet motor. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a diagram showing a structure example of the power conversion device of Example 1.

[0023] Figure 2 is a diagram showing an example of the estimation operation section 7 of the coefficient of induced voltage.

[0024] Figure 3 is a diagram showing a control characteristic in a case where the power conversion device of the comparative example is used.

[0025] Figure 4 is a diagram showing a control characteristic in a case where the power conversion device of Example 1 is used.

[0026] Figure 5 is a diagram showing a structure example of a permanent magnet motor driving system for confirming the control characteristic of the power conversion device of Example 1.

[0027] Figure 6 is a diagram showing an example of the estimation operation section of the coefficient of induced voltage of Example 2.

[0028] Figure 7 Fig. 1 is a diagram showing an example of the estimation operation section of the induced voltage coefficient of Embodiment 1.

[0029] Figure 8 Fig. 2 is a diagram showing an example of the estimation operation section of the induced voltage coefficient of Embodiment 2.

[0030] Figure 9 Fig. 3 is a diagram showing an example of the estimation operation section of the induced voltage coefficient of Embodiment 3.

[0031] Figure 10 Fig. 4 is a diagram showing an example of the estimation operation section of the induced voltage coefficient of Embodiment 4.

[0032] Figure 11 Fig. 5 is a diagram showing an example of the estimation operation section of the induced voltage coefficient of Embodiment 5.

[0033] Figure 12 Fig. 6 is a diagram showing an example of the structure of the power conversion device of Embodiment 6.

[0034] Figure 13 Fig. 7 is a diagram showing an example of the structure of the permanent magnet motor drive system of Embodiment 9. DETAILED DESCRIPTION

[0035] Hereinafter, several preferred embodiments will be described in detail using the drawings. In the drawings, the same reference numerals are added to common structures in the respective drawings. In addition, each of the embodiments described below is an example and is not limited to these embodiments.

[0036] Embodiment 1

[0037] Figure 1 Fig. 1 is a diagram showing an example of the structure of the power conversion device of Embodiment 1.

[0038] The power conversion device 1 includes a permanent magnet motor 10, a power converter 2, a direct current power supply 3, a current detector 4, a coordinate conversion section 5, a speed control operation section 6, an estimation operation section 7 of the induced voltage coefficient, a vector control operation section 8, a frequency / phase estimation operation section 9, and a coordinate conversion section 11. In a preferred example, the permanent magnet motor 10, the power converter 2, the direct current power supply 3, and the current detector 4 are constituted by hardware, and the other constituent sections 5 to 11 are functions (software functions) realized by executing programs in one or a plurality of processing devices (CPUs). The constituent sections 5 to 11 are sometimes simply referred to as a control section or a controller.

[0039] Here, the permanent magnet motor 10 outputs a motor torque obtained by synthesizing a torque component due to the magnetic flux of a permanent magnet and a torque component due to the inductance of an armature winding.

[0040] The power converter 2 inputs a three-phase AC voltage command value V. u * v v * v w * Output and voltage command value v u * v v * v w * The proportional voltage value allows for variable control of the output voltage and frequency of the permanent magnet motor 10. The DC power supply 3 provides DC voltage to the power converter 2.

[0041] Current detector 4 detects the three-phase AC current i of permanent magnet motor 10. u i v i w Output detection value i uc i vc i wc Additionally, the current detector 4 can also detect the AC current of two phases of the three-phase induction motor 1, such as phase u and phase w, based on the AC conditions (i... u +i v +i w =0), press i v =-(i u +i w Find the alternating current of phase v.

[0042] Coordinate transformation unit 5 is based on the three-phase alternating current i u i v i w The detection value i uc i vc i wc , and phase calculation value θ dc To output the current detection values ​​i on the d-axis and q-axis dc i qc .

[0043] Speed ​​control arithmetic unit 6 is based on frequency command value ω r * and frequency-calculated value ω r ^ Calculate the torque command value τ * The current command value i of the q-axis is output by dividing by the torque coefficient. q * .

[0044] The calculation unit 7 for the induced voltage coefficient is based on the voltage command values ​​v of the d-axis and q-axis. dc ** vqc ** , current detection value i dc , i qc , current command value i dc * , i qc * , frequency estimation value ω r ^ , to calculate and output an estimation value K of the induction voltage coefficient e ** .

[0045] The vector control operation section 8 outputs a d-axis and q-axis current command value i based on the estimation value K of the induction voltage coefficient e ** , d-axis and q-axis current command value i d * , i q * , current command value i dc , i qc , frequency estimation value ω as the output frequency r ^ , d-axis and q-axis voltage command value v calculated from the d-axis and q-axis current command value i dc ** , v qc ** .

[0046] The frequency / phase estimation operation section 9 uses the d-axis and q-axis voltage command value v as the control axes, the d-axis and q-axis current detection value i c , v c , q-axis inductance value L dc ** , frequency estimation value ω qc ** , to calculate a rotation phase estimation value θ of the power converter 2 q * , and the circuit constant of the permanent magnet motor 10, and outputs a frequency estimation value ω and a phase estimation value θ based on an estimation value of a phase error Δθ that is a deviation of the actual rotation phase θ from the rotation phase estimation value θ r ^ , current detection value i dc , i qc . dc d r ^ , phase estimation value θ dc .

[0047] The coordinate conversion section 11 converts the d-axis and q-axis voltage command value v dc * , v qc ** , and the phase estimation value θ dc ​​voltage command value v u * , v v * , v w * .

[0048] First, the basic operation of the sensorless vector control system with the use of the induction voltage coefficient calculation unit 7 as a feature of the present embodiment will be described.

[0049] The speed control calculation unit 6 calculates the frequency estimation value ω r ^ in such a manner that the tracking frequency command value ω r * is calculated by proportional control and integral control in accordance with equation (2) to calculate the torque command τ*and the q-axis current command value i q * .

[0050] [Equation 2]

[0051]

[0052] Here, K sp : proportional gain of the speed control, K si : integral gain of the speed control, P m : number of pole pairs

[0053] In the vector control calculation unit 8, first, the set value R * , the set value L d * , the set value L q * , the value K e * , the current command value i d * , i q * , and the frequency estimation value ω r ^ are inputted, and the voltage reference value v dc * , v qc * are outputted in accordance with equation (3).

[0054] [Equation 3]

[0055]

[0056] Here, T acr : response time constant of the current control

[0057] Second, to make the current detection value i of each component dc i qc Tracking the current command values ​​i on the d-axis and q-axis d * i q * The voltage correction values ​​Δv for the d-axis and q-axis are calculated using proportional control and integral control according to equation (4). dc Δv qc .

[0058] [Mathematical Expression 4]

[0059]

[0060] Here,

[0061] K pd d-axis current-controlled proportional gain, K id Integral gain of d-axis current control

[0062] K pq : proportional gain controlled by q-axis current, K iq The integral gain of the q-axis current control is then calculated according to equation (5) to determine the voltage command values ​​v of the d-axis and q-axis. dc ** v qc ** .

[0063] [Mathematical Expression 5]

[0064]

[0065] In the frequency / phase calculation unit 9, the voltage command value v based on the d-axis and q-axis is calculated. dc ** v qc ** Current detection value i dc i qc The circuit constants of the permanent magnet motor 10 are calculated according to equation (6) to estimate the phase error Δθ. C The value ω is calculated based on the frequency of operation according to formula (7). r ^ The phase value θ is calculated according to equation (8). dc .

[0066] [Mathematical Expression 6]

[0067]

[0068] [Mathematical Expression 7]

[0069]

[0070] [Math. 8]

[0071]

[0072] Here, Kp pll : proportional gain of the PLL control, Ki pll : integral gain of the PLL control

[0073] Figure 2 A structure example of the estimation operation part 7 that indicates the coefficient of the induced voltage in Embodiment 1.

[0074] The initial value 71 of the coefficient of the induced voltage is K e * . The first active power operation part 72 uses the voltage command values vd dc ** , vq qc ** , and the current detection values id dc , iq qc , and operates the first active power P c according to Equation (9).

[0075] [Math. 9]

[0076] P c = vd dc ** id dc + vq qc ** iq qc --------------------------------(9)

[0077] In order to cope with the operation mode of both the motoring and the regeneration, the output of the first active power operation part 72 is passed through the absolute value operation part 73, and the absolute value |P c | of the first active power P c is operated.

[0078] The second active power operation part 74 uses the current command values id d * , iq * , the frequency estimation value ω r , R, L d , L q , which are the circuit constants of the permanent magnet motor 10, and the estimation value K e ** of the coefficient of the induced voltage, and operates the second active power P c according to Equation (10).

[0079] [Equation 10]

[0080] P c d *2 i q *2 d * -L q * i a * i q * +ω r e ** i q * ---------------(10)

[0081] In order to cope with the operation mode of both power / regeneration, the output of the second effective power arithmetic unit 74 is passed through the absolute value arithmetic unit 75, and the absolute value |P c | of the second effective power P c is calculated.

[0082] The PI control unit 76 performs P (proportional) + I (integral) control in such a manner that the absolute value |P c | of the first effective power P c traces the absolute value |P c | of the second effective power P c , and calculates the correction value ΔK e0 of the induction voltage coefficient. * .

[0083] The low pass filter (L.P.F) 77 has a gain with a time constant of T, inputs the correction value ΔK e0 * of the induction voltage coefficient, and outputs the correction value ΔK e * . Using the correction value ΔK e * and the initial value K e * of the induction voltage coefficient, the estimated value K e ** of the induction voltage coefficient is calculated in accordance with Equation (11).

[0084] [Equation 11]

[0085] K e ** = ΔK e * + K e * ​​-----------------------(11)

[0086] Next, regarding the high-precision control characteristics achieved using this embodiment ( Figure 4 Using comparative examples () Figure 3 (This will be explained.)

[0087] Figure 3 This represents a comparative example (i.e., ΔK) that does not use the calculation unit 7 for the induced voltage coefficient of this embodiment. e * Control characteristics when =0).

[0088] The torque command value τ shown in equation (2) is illustrated. * and the current command value i on the q-axis q * The voltage command values ​​v of the d-axis and q-axis shown in equation (5) dc ** v qc ** The formula includes the set value K. e * The simulation results are given under the condition that errors exist.

[0089] The upper part represents the torque command value τ. * The middle part represents the frequency command ω. r * and the frequency ω of the permanent magnet motor r The lower part represents the induced voltage coefficient K. e and its set value K e * .

[0090] Figure 3 Imagine applying a ramp-shaped load torque starting at time A and varying it until time B. Due to the heat generated by the current, an induced voltage coefficient K is generated starting at point C. e The torque gradually decreases. After point B (on the right), the applied torque is maintained. It can be seen that the frequency ω of the permanent magnet motor is generated in interval D of the diagram. r / 2p and instruction value ω r * A deviation of / 2π.

[0091] On the other hand, in this embodiment, the voltage command values ​​v of the d-axis and q-axis are used. dc * v qc * and current detection value i dc i qc The set value K, which does not include the induced voltage coefficient, is calculated using equation (9). e* The first effective power P of the information c Furthermore, the current command values ​​i along the d-axis and q-axis are used. d * i q * Frequency calculation value ω r ^ The circuit constants R and L of a permanent magnet motor d L q And the calculated value K of the induced voltage coefficient e ** The second effective power P is calculated using equation (10). c ^ .

[0092] To make the second effective power P c ^ absolute value | P c ^ |Tracing the first effective power P c absolute value | P c The method of estimating the induced voltage coefficient K e ** Automatic adjustment will be performed to adjust the calculated value K. e ** It is used in the speed control calculation unit 6 and the vector control calculation unit 8, thereby improving the control characteristics with high precision.

[0093] exist Figure 4 The control characteristics of this embodiment are shown in the figure.

[0094] In this embodiment, the calculation unit 7 for the induced voltage coefficient is activated, and an application is made to... Figure 3 The comparison example uses the same load torque. This is because the induced voltage coefficient K is calculated with high accuracy. e (K e ≈K e ** Therefore, the frequency deviation (ω) in region D of the diagram is... r / 2p-ω r ^ The / 2p) is also relatively small, indicating that it has high-precision control characteristics.

[0095] <Confirmation of Control Characteristics>

[0096] Next, use Figure 5 The confirmation of the control characteristics of this embodiment will be explained.

[0097] For the electric power conversion device 1 that drives the permanent magnet motor 10, a voltage detector 21, a current detector 22, and an encoder 23 are connected, and the encoder 23 is attached to the shaft of the permanent magnet motor 10. Further, for the voltage detector 21, the current detector 22, and the encoder 23, a personal computer (PC) is connected, for example, and the respective detection values thereof are acquired, and processing is performed by executing a program. This processing mainly performs processing of the vector voltage / current component calculation section 24 and processing of the calculation section 25 using Equation 12.

[0098] That is, the vector voltage / current component calculation section 24 receives the output of the voltage detector 21, that is, the voltage detection values (v uc , v vc , v wc ) of three-phase alternating current, the current detection values (i uc , i vc , i wc ) of three-phase alternating current, and the output of the encoder, that is, the position θ, and calculates the vector voltage components v dc , v qc , the vector current components i dc , i qc , and the detection value ω rc that is obtained by differentiating the position θ.

[0099] The calculation section 25 calculates the estimated value K e ^ of the induced voltage coefficient using Equation 12.

[0100] [Equation 12]

[0101]

[0102] It is known that even if the induced voltage coefficient K e * that is set for the controller of the electric power converter 2 is deviated (changed), the magnitude of the induced voltage coefficient K e ^ does not change, and can be accurately detected. By displaying the value of the induced voltage coefficient K e * relative to the induced voltage coefficient K e ^ on the screen of the PC, or a graph that indicates the transition of these coefficients, the effect of the control characteristics of the present embodiment can be confirmed.

[0103] In addition, in the present embodiment, the frequency estimated value ωr ^ is calculated, but an encoder can be attached to the permanent magnet motor 10, and the frequency ω rc can be detected.

[0104] According to the present embodiment, even if the inductance set values L d* L q * There is an error in the data; simply adjust the d-axis current command value i. d * When set near zero, the second component of equation (10) will reduce sensitivity, so high-precision control characteristics can be achieved regardless of the power / regenerative operation mode.

[0105] Example 2

[0106] refer to Figure 6 The power conversion device of Example 2 will be described. Figure 6 An example of the calculation unit 7 that represents the induced voltage coefficient.

[0107] In Example 1, in the calculation unit 7 for the induced voltage coefficient, the gain (K) of the proportional control and integral control is calculated. p K i The value is set to a fixed value. On the other hand, in Example 2, the frequency-calculated value ω is... r ^ and the current command value i on the q-axis q * Change the gain (K) accordingly p K i ).

[0108] Figure 6 The calculation unit 7 for the induced voltage coefficient shown is the same as that in Embodiment 1 ( Figure 2 The calculation unit 7 for the induced voltage coefficient has the same structure as that in Embodiment 1. The input and output values ​​of the PI control 762 differ from those in Embodiment 1, but other components are the same. Figure 2 same.

[0109] In Example 2, in the PI control 762, the frequency-calculated value ω is... r ^ and the current command value i on the q-axis q * The gain (K) of the proportional control and integral control is changed approximately proportionally. p K i Thus, the first effective power P c absolute value | P c |The second effective power P varies accordingly with the frequency and current value. c ^ absolute value | P c ^ Therefore, it is possible to achieve shorter control times and higher precision in both low-speed and high-speed ranges, and in light-load and heavy-load environments.

[0110] Example 3

[0111] refer to Figure 7 The power conversion device of Example 3 will be described. Figure 7 An example of the calculation unit 7 that represents the induced voltage coefficient.

[0112] In Example 1, voltage command values ​​v based on the d-axis and q-axis were used. dc ** v qc ** and current detection value i dc i qc Calculate the first effective power P c The structure. On the other hand, in Embodiment 3, the amplitude value V1 of the voltage command used is three-phase AC. * The amplitude value i1 and phase θ of the current detection vi The cosine signal is used to calculate the effective power P. c .

[0113] Figure 7 The calculation unit 7 for the induced voltage coefficient shown is the same as that in Embodiment 1 ( Figure 2 The calculation unit 7 for calculating the induced voltage coefficient has the same structure as that in Embodiment 1. The calculations in the first effective power calculation unit 723 differ from those in Embodiment 1, but other components are the same. Figure 2 Same. That is, Figure 7 In the first effective power calculation unit 723, the amplitude value V1 of the three-phase AC voltage command is calculated using equation (13). * The amplitude value i1 of the current detection value is obtained using equation (14), and the phase θ is obtained using equation (15). vi The effective power P is calculated using equation (16). c .

[0114] [Mathematical Expression 13]

[0115]

[0116] [Mathematical Expression 14]

[0117]

[0118] [Mathematical Expression 15]

[0119]

[0120] [Mathematical Expression 16]

[0121] P c =v1 * i1cos[θ vi ]-------------------------(16)

[0122] According to Example 3, the same high-precision control characteristics can be achieved as in Example 1.

[0123] Example 4

[0124] refer to Figure 8 The power conversion device of Example 4 will be described. Figure 8 An example of the calculation unit 7 that represents the induced voltage coefficient.

[0125] In Example 1, based on the voltage command values ​​v of the d-axis and q-axis dc ** v qc ** and current detection value i dc i qc Calculate the first effective power P c In Example 4, the DC voltage value E of power converter 2 is used. DC and DC current value I DC Operational effective power P c .

[0126] Figure 8 The calculation unit 7 for the induced voltage coefficient shown is the same as that in Embodiment 1 ( Figure 2 The calculation unit 7 for calculating the induced voltage coefficient has the same structure as that in Embodiment 1. The calculation in the first effective power calculation unit 724 differs from that in Embodiment 1, but other components are the same. Figure 2 Same. That is, Figure 8 In the first effective power calculation unit 724, the DC voltage detection value E of the power converter 2 is used. DC DC current detection value I DC The first effective power P is calculated based on equation (17). c .

[0127] [Mathematical Expression 17]

[0128]

[0129] According to Example 4, similar to Example 1, high-precision control characteristics can be achieved.

[0130] Example 5

[0131] refer to Figure 9 The power conversion device of Example 5 will be described. Figure 9 An example of the calculation unit 7 that represents the induced voltage coefficient.

[0132] In Example 1, the first and second effective power were used, but in Example 5, the two reactive power were used.

[0133] Figure 9The shown induced voltage coefficient estimation operation part 7 is the same structure as the induced voltage coefficient estimation operation part 7 of Embodiment 1 Figure 2 ). The operation in the first reactive power operation part 725 and the second reactive power operation part 745 is different from the first active power operation part 72 and the second active power operation part 74 in Embodiment 1, but the other constituent parts are the same as Figure 2 . That is, the first reactive power operation part 725 uses the voltage command values v dc * , v qc * and the current detection values i dc , i qc , and operates the first reactive power Q c according to Equation (18).

[0134] [Equation 18]

[0135] Q c = v dc ** i qc -v qc ** 1 dc --------------------------(18)

[0136] In order to cope with the operation mode of both power / regeneration, the output of the first reactive power operation part 725 passes through the absolute value operation part 73, and the absolute value |Q c | of the first reactive power Q c is operated.

[0137] The second reactive power operation part 745 uses the current command values i dc * , i qc * , the frequency estimation value ω r , R, L d , L q , which are circuit constants of the permanent magnet motor 10, and the estimation value K e ** of the induced voltage coefficient, and operates the second reactive power Q c according to Equation (19).

[0138] [Equation 19]

[0139] Q c = - ω r (L d * i d *2 + L q* i q *2 )-ω r ^K e ** -------------------------(19)

[0140] To accommodate the operating modes of both power and regeneration, the output of the second reactive power calculation unit 745 is processed by the absolute value calculation unit 75 to calculate the second reactive power Q. c The absolute value of ^|Q c ^|。 The PI control unit 76 makes the first reactive power Q c absolute value | Q c | Tracking the second reactive power Q c The absolute value of ^|Q c The control is performed using the P (proportional) + I (integral) method, and the correction value ΔK of the induced voltage coefficient is calculated. eo * .

[0141] The LPF77 has a gain with a time constant of T and a correction value ΔK for the input induced voltage coefficient. e0 * Calculation correction value ΔK e * Use the correction value ΔK e * and the set value K of the induced voltage coefficient e * The calculated value K of the induced voltage coefficient is obtained according to equation (11). e ** .

[0142] According to Example 5, the second reactive power Q is made... c The absolute value of ^|Q c ^| Tracking the first reactive power Q c absolute value | Q c | Method to correct the set value K of the induced voltage coefficient e * Therefore, even if the resistance setting value R... * The error exists, but it is unrelated to the power / regenerative operation mode, and can achieve high-precision control characteristics.

[0143] Example 6

[0144] refer to Figure 10 The power conversion device of Example 6 will be described. Figure 10 An example of the calculation unit 7 that represents the induced voltage coefficient.

[0145] Example 6 also calculates the reactive power as in Example 5. In Example 5, the voltage command value v dc ** , the current detection value i qc ** , and the current detection value i dc qc The first reactive power Q c is calculated, but in Example 6, the amplitude value V1 * of the voltage command of the three-phase alternating current and the amplitude value i1 of the current detection, and the phase θ vi are used to calculate the reactive power Q c .

[0146] Figure 10 The estimation operation section 7 of the induced voltage coefficient shown in FIG. 7 is the same structure as the estimation operation section 7 of the induced voltage coefficient of Example 5. Figure 9 The operation in the first reactive power operation section 726 is different from that of the first reactive power operation section 725 of Example 5, but the other components are the same as Figure 9 .

[0147] Figure 10 In the first reactive power operation section 726, the amplitude value V1 * of the voltage command of the three-phase alternating current is calculated by Equation (13), the amplitude value i1 of the current detection is calculated by Equation (14), and the reactive power Q vi is calculated by Equation (20) using the sine signal of the phase θ c .

[0148] [Equation 20]

[0149] Q c = V1 * i1 sin [θ vi ]----------------------------(20)

[0150] According to Example 6, as in Example 5, high-precision control characteristics can be achieved regardless of the torque mode of the power / regeneration.

[0151] Example 7

[0152] With reference to Figure 11 , the power conversion device of Example 7 is described. Figure 11 An example of the estimation operation section 7 of the induced voltage coefficient is shown.

[0153] ​Embodiments 1 to 3 use the method of operating the effective power, and Embodiments 4 to 5 use the method of operating the reactive power, but Embodiment 7 is a structure that uses the reactive power method in the low speed range and the effective power method in the high speed range, and switches between the two.

[0154] Figure 11 Among them, the estimation operation section 7112 of the induced voltage coefficient corresponds to the estimation operation section 7 of the induced voltage coefficient in Embodiment 1 ( Figure 2 ), and the estimation operation section 7114 of the induced voltage coefficient corresponds to the estimation operation section 7 of the induced voltage coefficient in Embodiment 5 ( Figure 9 ). In addition, Figure 11 The first effective power operation section 72 and the second effective power operation section 74, and the first reactive power operation section 725 and the second reactive power operation section 745 in the estimation operation section 7 of the induced voltage coefficient are mainly focused on and illustrated, and the illustration of other constituent parts is omitted.

[0155] The switching switch 716 selects the output signal of the estimation operation section 7114 of the induced voltage coefficient in the low speed range, and selects the output signal of the estimation operation section 7112 of the induced voltage coefficient in the medium to high speed range, and outputs as the estimated value K e ** . This switching operation can be performed, for example, by using the circuit constant of the permanent magnet motor 10 and the frequency estimated value ω r ^ , and if the formula (21) is satisfied, it is judged as the medium to high speed range, and if it is not satisfied, it is judged as the low speed range.

[0156] [mathematical formula 21]

[0157]

[0158] According to Embodiment 7, in the low speed range, the sensitivity of the setting error of the resistance can be reduced (i.e., because the resistance is not included in the formula (19)). In the medium to high speed range, the sensitivity of the setting error of the inductance can be reduced (i.e., because the difference (L d * -L q * ) is reduced). Thus, a high precision control characteristic can be achieved in the entire speed range.

[0159] Embodiment 8

[0160] Figure 12 is a configuration diagram of the power conversion device of Embodiment 8.

[0161] Embodiments 1 to 7 are examples of operating the electric power and estimating the induced voltage coefficient. In contrast, Embodiment 8 is an example of estimating the temperature of the permanent magnet motor 10.

[0162] Figure 12 In the power conversion device 1 shown, a rotor temperature estimation operation section 121, a PLC (Programmable Logic Controller) that manages the state of the permanent magnet motor, and a higher-level controller 122 such as an IOT are added. The other structures are the same as in Figure 1

[0163] The rotor temperature estimation operation section 121 uses the estimated value K e ** of the inductive voltage coefficient to calculate the rotor temperature estimation value Temp (°C) of the permanent magnet motor 10 using Equation (27). Here, it is assumed that the inductive voltage coefficient decreases by 10% when the temperature changes by 100°C, and that the inductive voltage coefficient at a temperature of 20°C is K e0 .

[0164] [Equation 22]

[0165]

[0166] Further, the temperature estimation value Temp is fed back to the controller 122, and the controller 122 determines the optimal mode of the torque current command id* and the excitation current command using Equation (28).

[0167] [Equation 23]

[0168]

[0169] According to Embodiment 8, as with Embodiment 1, a high-precision control characteristic can be achieved.

[0170] Embodiment 9

[0171] Reference Figure 13 A permanent magnet motor drive system according to Embodiment 9 will be described. Embodiment 9 indicates an example in which the power conversion device according to Embodiments 1 to 8 is applied to a permanent magnet motor drive system.

[0172] The permanent magnet motor drive system has the power conversion device 1 and an induction motor 1 driven thereby. Further, in one example, for the power conversion device 1, a terminal 31 such as a personal computer (PC) 311, a tablet 312, a smartphone 313, or the like is connected. In addition, in the power converter 2 mounted in the power conversion device 1 or the internal memory of a microcomputer including other constituent parts, the response frequency or the control gain (proportional gain 26, integral gain 27) of the control set for the proportional control or the integral control is set. The terminal 31 can also be referred to as a higher-level device in relation to the control of the power conversion device 1.

[0173] ​In one example, the proportional gain 26 and the integral gain 27 of the power conversion device 1 can be set or changed according to an instruction from the terminal 31. In another example, the proportional gain 26 and the integral gain 27 of the power conversion device 1 can be set or changed according to an instruction of the digital operator 112 provided to the power conversion device 1.

[0174] Further, the proportional gain 26 and the integral gain 27 described above can be set on a field bus of an IOT controller or the like connected to a PLC or a computer.

[0175] Further, Figure 13 The power conversion device 1 of Embodiment 1 is shown in the above example, but the power conversion device 1 of Embodiments 2 to 6 can also be used. Figure 1

[0176] According to the induction motor drive system of Embodiment 9, high-precision control characteristics can be achieved in position sensorless vector control.

[0177] Embodiment 10

[0178] Other Modified Examples

[0179] The above-described Embodiments 1 to 8 can be further modified and implemented in various ways. Hereinafter, several modified examples will be described. For example, in Embodiments 1 to 2, the current detection values i dc , i qc are used in the formula (9) of the first active power Pc and the formula (18) of the first reactive power Qc, but the current command values i d , i q may also be used. Further, the current command values i d * , i q * are used in the formula (10) of the second active power Pc and the formula (19) of the second reactive power Qc, but the current detection values i dc , i qc may also be used.

[0180] Further, in Embodiments 1 to 7, the voltage correction values Δv d * , Δv q * are generated from the current command values i dc , i qc , the operation shown in the formula (3) in which the voltage correction values are added to the voltage reference values of the vector control, but the voltage correction values Δv dc , Δv qc may also be generated from the current command values i d * , i q ​* and the current detection value i dc , i qc The intermediate current command value i shown in Equation (22) used in the vector control operation is generated d ** , i q ** Equation (23) using the frequency estimation value ω r ^ and the circuit constant of the permanent magnet motor 10.

[0181] [Equation 24]

[0182]

[0183] [Equation 25]

[0184]

[0185] Here,

[0186] K pd1 : proportional gain of d-axis current control, K id1 : integral gain of d-axis current control, K pq1 : proportional gain of q-axis current control, K iq1 : integral gain of q-axis current control, T d : d-axis electrical time constant (L d / R), T q : q-axis electrical time constant (L q / R)

[0187] In addition, as another example, the voltage correction value Δv of the proportional operation component of the d-axis used in the vector control operation can also be generated using Equation (24) based on the current command value i d ** , i q * and the current detection value i dc , i qc d_p * , the voltage correction value Δv of the integral operation component of the d-axis d_i * , the voltage correction value Δv of the proportional operation component of the q-axis q_p * , the voltage correction value Δv of the integral operation component of the q-axis q_i * r ^ Equation (25) using the frequency value estimation ω

[0188] ​​[Math. 26]

[0189]

[0190] [Math. 27]

[0191]

[0192] Here,

[0193] K pd2 : proportional gain of d-axis current control, K id2 : integral gain of d-axis current control, K pq2 : proportional gain of q-axis current control, K iq2 : integral gain of q-axis current control

[0194] In addition, a first-order lag signal i d * of the current command value i qc of the d-axis and the current detection value i qctd of the q-axis, a frequency estimation value ω r ^ and a circuit constant of the induction motor 1 can be used to perform vector control operation using equation (26).

[0195] [Math. 28]

[0196]

[0197] Furthermore, as another example, in the above-described embodiment, the frequency estimation value is calculated using equation (7) in the frequency / phase estimation operation section 9, but an encoder can be installed on the permanent magnet motor 10, and a frequency detection value can be calculated from the encoder signal.

[0198] In addition, in the preferred example (refer to Figure 1 ) of the power conversion device 1, the permanent magnet motor 10, the power converter 2, the direct current power supply 3, and the current detector 4 are configured by hardware, and the other configuration sections 5 to 10 are implemented by executing a program in a processing device (CPU), but according to another example, a part or all of the other configuration sections 5 to 10 can be configured by hardware.

[0199] In addition, in all of the above-described embodiments, the switching element that configures the power converter 2 can be a Si (silicon) semiconductor element, or a wide band gap semiconductor element such as SiC (silicon carbide) or GaN (gallium nitride).

[0200] As described above, according to the several embodiments, by using the active power or the reactive power, a power conversion device having a control characteristic with high precision without adjusting the circuit constant of the permanent magnet motor set to the controller can be implemented.

[0201] Reference Signs

[0202] 1…power conversion device, 10…permanent magnet motor, 2…power converter, 3…DC power supply, 4…current detector, 5…coordinate conversion section, 6…speed control operation section, 7…estimation operation section of induction voltage coefficient, 8…vector control operation section, 9…frequency / phase estimation operation section, 11…coordinate conversion section,

[0203] 121…rotor temperature estimation operation section, 122…controller,

[0204] 112…digital operator of power conversion device, 21…voltage detector, 22…current detector, 23…encoder, 24…calculation section of vector current component, 25…observation section of current waveform of each section, 26…proportional gain, 27…integral gain, 31…terminal

[0205] i d * …current command value of d-axis, i q * …current command value of q-axis, ω r ^ …frequency estimation value, ω r …frequency of permanent magnet motor 10, v dc * , v dc ** , v dc *** , v dc **** , v dc ***** …voltage command value of d-axis,

[0206] v qc * , v qc ** , v qc *** , v qc **** , v qc ***** …voltage command value of q-axis, P C …first active power, P C ^ …second active power, Q C …first reactive power, Q C ^ …second reactive power, K e * …set value of induction voltage coefficient, ΔK e * …correction value of induction voltage coefficient, Ke ** …the estimated value of the inductive voltage coefficient.

Claims

1. A power conversion device for controlling a permanent magnet motor, characterized in that: The first electric power is calculated based on the output voltage and output current of the permanent magnet motor. The second electric power is calculated based on the circuit constants, current command, output frequency, and induced voltage coefficient of the permanent magnet motor. The induced voltage coefficient is calculated in such a way that the first electrical power tracks the second electrical power. The drive of the permanent magnet motor is controlled according to the induced voltage coefficient. The first electrical power is the first effective power calculated based on the output voltage and output current of the permanent magnet motor. The second electrical power is a second effective power calculated based on the circuit constants, current command, output frequency, and induced voltage coefficient of the permanent magnet motor. The first electrical power is the first reactive power calculated based on the output voltage and output current of the permanent magnet motor. The second electrical power is a second reactive power calculated based on the circuit constants, current command, output frequency, and induced voltage coefficient of the permanent magnet motor. The induced voltage coefficient is calculated in a manner that makes the deviation between the first effective power and the second effective power zero, or makes the deviation between the first reactive power and the second reactive power zero. Based on the relationship between the circuit constants and the calculated frequency of the permanent magnet motor, When the permanent magnet motor is in the low-speed range, proportional control and integral control are performed in a manner that makes the deviation between the first effective power and the second effective power zero. When the permanent magnet motor is in the medium-to-high speed range, proportional control and integral control are performed in a manner that makes the deviation between the first reactive power and the second reactive power zero.

2. The power conversion device as described in claim 1, characterized in that: It has a vector control calculation unit that uses the current command values ​​and current detection values ​​of the flux axis (d-axis) and torque axis (q-axis) of the permanent magnet motor, as well as the output frequency, to output the voltage command values ​​of the d-axis and q-axis. The first effective power is obtained by multiplying the voltage command values ​​and current detection values ​​of the same components of the d-axis and q-axis and then adding them together. The second effective power is calculated from the circuit constants, d-axis and q-axis current command values, output frequency, and induced voltage coefficient of the permanent magnet motor. The induced voltage coefficient is controlled in such a way that the first effective power tracks the second effective power.

3. The power conversion device as described in claim 1, characterized in that: It has a vector control calculation unit that uses the current command values ​​and current detection values ​​of the flux axis (d-axis) and torque axis (q-axis) of the permanent magnet motor, as well as the output frequency, to output the voltage command values ​​of the d-axis and q-axis. The first effective power is obtained by multiplying the DC voltage detection value and the DC current detection value of the power converter. The second effective power is calculated from the circuit constants, d-axis and q-axis current command values, output frequency, and induced voltage coefficient of the permanent magnet motor. The induced voltage coefficient is controlled in such a way that the first effective power tracks the second effective power.

4. The power conversion device as described in claim 1, characterized in that: It has a vector control calculation unit that uses the three-phase AC current command value, current detection value, and output frequency of the permanent magnet motor to output the three-phase AC voltage command value. The first effective power is obtained by multiplying the voltage amplitude and current amplitude of one phase of the three-phase AC circuit with the cosine signal of the phase difference between the voltage command value and the current detection value. The second effective power is calculated from the circuit constants, d-axis and q-axis current command values, output frequency, and induced voltage coefficient of the permanent magnet motor. The induced voltage coefficient is controlled in such a way that the first effective power tracks the second effective power.

5. The power conversion device as described in claim 1, characterized in that: It has a vector control calculation unit that uses the current command values ​​and current detection values ​​of the flux axis (d-axis) and torque axis (q-axis) of the permanent magnet motor, as well as the output frequency, to output the voltage command values ​​of the d-axis and q-axis. The first reactive power is obtained by multiplying the voltage command values ​​of different components of the d-axis and q-axis with the current detection values ​​and then subtracting the results. The second reactive power is calculated from the circuit constants of the permanent magnet motor, the current command values ​​of the d-axis and q-axis, the output frequency, and the induced voltage coefficient. The induced voltage coefficient is controlled in such a way that the first reactive power tracks the second reactive power.

6. The power conversion device as described in claim 1, characterized in that: It has a vector control calculation unit that uses the three-phase AC current command value, current detection value, and output frequency of the permanent magnet motor to output the three-phase AC voltage command value. The first reactive power is calculated by multiplying the voltage amplitude and current amplitude of one phase of the three-phase AC circuit with the sinusoidal signal of the phase difference between the voltage command value and the current detection value. The second reactive power is calculated from the circuit constants of the permanent magnet motor, the current command values ​​of the d-axis and q-axis, the output frequency, and the induced voltage coefficient. The induced voltage coefficient is controlled in such a way that the first reactive power tracks the second reactive power.

7. The power conversion device as described in claim 1, characterized in that: The control gain of the proportional control and the integral control is automatically corrected based on at least one of the output frequency of the permanent magnet motor and the current command value of the q-axis.

8. The power conversion device as described in claim 1, characterized in that: The response frequency or control gain set in the proportional control or integral control can be set or changed according to the instructions from the terminal connected to the power conversion device or the digital operator of the power conversion device.

9. The power conversion device as described in claim 1, characterized in that: It has a rotor temperature estimation calculation unit that uses the induced voltage coefficient to estimate the rotor temperature inside the permanent magnet motor.

10. The power conversion device as described in claim 9, characterized in that: The induced voltage coefficient is fed back to the controller, which determines the optimal mode for torque current command and excitation current command.

11. The power conversion device as described in claim 9, characterized in that: The induced voltage coefficient or the calculated value of the rotor temperature is fed back to the controller, which manages the state of the permanent magnet motor.

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