Power Conversion Equipment

Abstract

To provide a power conversion device preventing a motor speed and an oscillation phenomenon of torque in the presence of an error of a secondary resistance value.SOLUTION: A power conversion device has a power converter outputting to an induction motor a signal making an output frequency of the induction motor, output voltage, and output current variable, and a control part controlling the power converter. The control part calculates power from the output voltage and the output current in a control axis making a direction of primary current and direction orthogonal thereto a rotation coordinate system, calculates a power model from the output current in the control axis and a circuit parameter, and calculates a speed estimated value from the power and the power model.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] In Patent Document 1, the direction of the primary current (t-axis) and the direction perpendicular to it (m-axis) are set as the control axes (mt-axis) of a rotating coordinate system, the back electromotive force value is estimated from the voltage command value of the m-axis, and the speed estimation value ω is calculated by dividing it by the magnetic flux according to (Equation 1). r ^ The following is calculated.

[0003]

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[0004] With this technology, the set value R1 used in (Equation 1) * Even if there is an error in the primary resistance value R1 of the induction motor, the estimated speed value ω r ^ The estimation error (ω r ^ -ω r ) does not occur, and there is a description that stable speed control can be performed. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2018-182989 A Summary of the Invention [Problem to be solved by the invention]

[0006] The technology of Patent Document 1 is based on the error in the primary resistance value R1 of the induction motor (R1 * -R1), but the secondary resistance setting value R2 used in (Equation 1) * and the secondary resistance value R2 of the induction motor has an error (R2 * -R2), the estimated speed of the induction motor, ω r ^ This causes vibrations in the motor speed and torque.

[0007] An object of the present invention is to provide a power conversion device which prevents the vibration phenomenon of the motor speed and torque even when there is an error in the secondary resistance value. [Means for solving the problem]

[0008] The present invention provides a power converter that outputs signals to an induction motor to vary an output frequency, an output voltage, and an output current of the induction motor; A control unit that controls the power converter, The control unit is calculating power from the output voltage and the output current on a control axis defined by a rotation coordinate system including a direction of the primary current and a direction perpendicular thereto; The power conversion device calculates a power model from the output current in the control axis and circuit parameters, and calculates a speed estimate from the power and the power model. Effect of the Invention

[0009] According to the present invention, even if there is an error in the secondary resistance value, it is possible to prevent the oscillation phenomenon of the speed and torque of the induction motor. [Brief description of the drawings]

[0010] [Figure 1] 1 is a configuration diagram of a first embodiment including a power conversion device and an induction motor. [Diagram 2] Vector diagram of dq axis. [Diagram 3] Vector diagram of the mt axis in Example 1. [Figure 4] Load operation characteristics when using conventional technology (R1* has some error). [Diagram 5] Load operating characteristics when using conventional technology (R1* and R2* have errors). [Figure 6] FIG. 4 is a configuration diagram of a speed / frequency / phase calculation unit that uses the cross product of power in the first embodiment. [Figure 7] Load operating characteristics when using the present invention (R1* and R2* have errors). [Figure 8] FIG. 1 is a configuration diagram for confirming the feasibility of the present invention. [Figure 9] FIG. 11 is a configuration diagram of a speed / frequency / phase calculation unit that uses an inner product of power in the second embodiment. [Figure 10] FIG. 11 is a configuration diagram of a second embodiment having a power conversion device and an induction motor. [Figure 11] FIG. 11 is a configuration diagram of a speed / frequency / phase calculation unit in the third embodiment. [Figure 12] FIG. 13 is a configuration diagram of a fourth embodiment having a power conversion device and an induction motor. [Figure 13] FIG. 13 is a configuration diagram of a fifth embodiment having a power conversion device and an induction motor. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] This embodiment will be described in detail below with reference to the drawings. EXAMPLES

[0012] Fig. 1 is a configuration diagram of a first embodiment including a power conversion device and an induction motor. This embodiment is a power conversion device that drives the induction motor by speed sensorless vector control without using a speed sensor. This embodiment also relates to a power conversion device that can operate stably without torque shortage by suppressing torque loss and torque pulsation caused by the primary resistance value and secondary resistance value that change depending on the winding temperature in the induction motor.

[0013] The induction motor 1 generates a magnetic flux φ 2d and the torque axis component (q axis) of current i q This generates a torque τ.

[0014] The power converter 2 includes a semiconductor element as a switching element. The power converter 2 outputs a three-phase AC voltage command value v u * , v v * , v w * and the three-phase AC voltage command value v u * , v v * , v w * Based on the output of the power converter 2, the induction motor 1 is driven, and the output voltage, output frequency, and output current of the induction motor 1 are variably controlled. An IGBT (Insulated Gate Bipolar Transistor) may be used as the switching element.

[0015] The DC power supply 3 supplies a DC voltage and a DC current to the power converter 2 .

[0016] The current detector 4 detects the three-phase AC current i of the induction motor 1. u , i v , i w Detection value i uc , i vc , i wc The current detector 4 detects the phase currents of two of the three phases of the induction motor 1, for example, the U phase and the W phase, and outputs the AC condition (i u+i v +i w =0) to change the V-phase line current to i v =-(i u +i w ) may also be calculated.

[0017] In this embodiment, an example in which the current detector 4 is provided inside the power conversion device has been shown, but it may also be provided outside the power conversion device.

[0018] The control unit includes a coordinate conversion unit 5, a coordinate conversion unit 6, a speed / frequency / phase calculation unit 7a, a reference phase calculation unit 8, an excitation current / magnetic flux setting unit 9, a speed control calculation unit 10, a coordinate conversion unit 11, a coordinate conversion unit 12, an mt-axis vector control calculation unit 13, a coordinate conversion unit 14, and a coordinate conversion unit 15, which are described below. The control unit controls the output of the power converter 2 so as to variably control the output voltage value, the output frequency value, and the output current of the induction motor 1.

[0019] The control unit is composed of a semiconductor integrated circuit (arithmetic control means) such as a microcomputer (microcomputer) or a DSP (Digital Signal Processor). Any or all of the control unit can be composed of hardware such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array). The CPU (Central Processing Unit) of the control unit reads out a program stored in a recording device such as a memory, and executes the processing of each unit such as the coordinate conversion unit 5 described above.

[0020] Next, each component of the control unit will be described.

[0021] The coordinate conversion unit 5 converts the three-phase AC current i u , i v , i w Detection value i uc , i vc , i wc and the phase estimate θ dc to the d-axis and q-axis current detection values ​​i dc , i qcOutput.

[0022] The coordinate conversion unit 6 converts the d-axis and q-axis current detection values ​​i dc , i qc and phase angle θ mt m-axis and t-axis current detection values ​​i mc , i tc Output.

[0023] The speed / frequency / phase calculation unit 7a calculates the m-axis and t-axis current command values ​​i m * , i t * and the current detection value i mc , i tc , voltage command value v mc ** , v tc ** , magnetic flux command value φ m * , φ t * , Primary frequency command value ω1 * and the circuit parameters of induction motor 1 (R1, R2', L σ , M, L2) to obtain the estimated speed ω of the induction motor 1. r ^^ , slip frequency command value ω s * , Primary frequency command value ω1 * and the phase estimate θ dc Output.

[0024] The reference phase calculation unit 8 calculates a slip frequency command value ω s * Using the estimated phase angle θ from the m-axis to the d-axis mt Output.

[0025] The excitation current / magnetic flux setting unit 9 sets the excitation current command value i d * and the positive polarity d-axis secondary magnetic flux command value φ 2d * And the secondary magnetic flux command value φ of the q-axis is "0". 2q * Output.

[0026] The speed control calculation unit 10 calculates a speed command value ω r * and the estimated speed ω r ^^ Deviation (ω r * -ω r ^^ ) to the q-axis current command value i q * Output.

[0027] The coordinate conversion unit 11 converts the d-axis and q-axis current command values ​​i d * , i q * and the estimated phase angle θ mt m-axis and t-axis current command values ​​i m * , i t * Output.

[0028] The coordinate conversion unit 12 converts the secondary magnetic flux command values ​​φ 2d * , φ 2q * and the estimated phase angle θ mt to the magnetic flux command value φ of the m-axis and t-axis m * , φ t * Output.

[0029] The mt-axis vector control calculation unit 13 calculates the circuit parameters (R1, R2 ‘ , L σ , M, L2), m-axis and t-axis magnetic flux command values ​​φ m * , φ t * , m-axis and t-axis current command values ​​i m * , i t * , current detection value i mc , i tc , the speed estimate ω r ^^, Primary frequency command value ω1 * Based on this, the m-axis and t-axis voltage command values ​​v mc ** , v tc** Output.

[0030] The coordinate conversion unit 14 converts the m-axis and t-axis voltage command values ​​v mc ** , v tc ** and the estimated phase angle θ mt to the d-axis and q-axis voltage command values ​​v dc ** , v qc ** Output.

[0031] The coordinate conversion unit 15 converts the d-axis and q-axis voltage command values ​​v dc ** , v qc ** and the phase estimate θ dc to the three-phase AC voltage command value v u * , v v * , v w * Output.

[0032] First, we will explain the mt-axis based on the primary current. The mt-axis is a rotating coordinate system and is the control axis. Figure 2 is a vector diagram on the dq-axis. The direction of the magnetic flux is the d-axis, and the direction 90 degrees (π / 2) ahead of the d-axis is the q-axis. Here, the current i on the d-axis d and the q-axis current i q and the primary current i1 are related by (Equation 2).

[0033]

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[0034] Also, i d and the phase angle θ of i1 φ is (Equation 3).

[0035]

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[0036] Figure 3 is a vector diagram of the mt axis. The direction of the primary current is the t axis, and the direction 90 degrees behind the t axis is the m axis.

[0037] Here, the m-axis current i m and the current i on the t axis t and the primary current i1 are related by (Equation 4).

[0038]

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[0039] Furthermore, the phase angle θ from the m-axis to the d-axis mt is (Equation 5).

[0040]

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[0041] The basic operation of the speed sensorless control method using the speed estimation calculation shown in (Equation 1) will be described.

[0042] The excitation current / magnetic flux setting unit 9 determines the secondary magnetic flux value φ of the d-axis in the induction motor 1. 2d The current command value I required to generate d * In addition, the speed control calculation unit 10 outputs a speed command value ω r * to the estimated speed ω r ^ The q-axis current command value i q * Calculate the following.

[0043]

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[0044] The vector control calculation unit 13 of the mt axis calculates the current command value id * , i q * The m-axis and t-axis current command values ​​i m * , i t * , the circuit parameters of induction motor 1 (R1, R2, L σ , M, L2), m-axis and t-axis magnetic flux command values ​​φ m * , φ t * , the speed estimate ω r ^^ , Primary frequency command value ω1 * Using this, the voltage reference value v mc * , v tc * Calculate the voltage reference value v mc * , v tc * are the feedforward voltage components of the m-axis and t-axis, respectively.

[0045]

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[0046] In addition, the vector control calculation unit 13 of the mt axis receives the current command value i m * , m-axis current detection value i mc , t-axis current command value i t * , t-axis current detection value i tc Here, the current command value i m * , i t * The current detection value of each component i mc , i tc The voltage correction value Δv on the m-axis and t-axis is calculated by PI (proportional + integral) control so that the voltage correction value Δv on the m-axis and t-axis is calculated so that the voltage correction value Δv on the t-axis is calculated. m * , Δv t * The voltage correction value Δv is output.m * , Δv t * are the m-axis and t-axis feedback voltage components, respectively.

[0047]

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[0048] Furthermore, according to (Equation 9), the voltage command value v mc ** , v tc ** After calculating the voltage command value v of the d-axis and q-axis after coordinate transformation, dc ** , v qc ** The output voltage of the power converter 2 is controlled by this.

[0049]

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[0050] In the above example, the voltage command value v mc ** , v tc ** are calculated from the feedback voltage components of the m-axis and t-axis, and the feedforward voltage components of the m-axis and t-axis, respectively. mc ** , v tc ** may be the feedback voltage components of the m-axis and t-axis.

[0051] Since this is a basic operation, the speed / frequency / phase calculation unit 7a calculates the speed estimate ω r ^^ Instead of r ^Also, according to (Equation 10), the slip frequency command value ω s * Calculate the following.

[0052]

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[0053] Furthermore, the speed estimate ω r ^ and slip frequency command value ω s * Using this, the primary frequency command value ω1 is calculated according to (Equation 11). * Calculate the following.

[0054]

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[0055] The phase estimation calculation unit 7a7 calculates the primary frequency command value ω1 according to (Equation 12). * From the flux axis phase θ of induction motor 1 dc Calculate the following.

[0056]

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[0057] Phase of magnetic flux axis θ d The phase estimate θ dc The sensorless control is then used as the control standard. This completes the basic operation.

[0058] FIG. 4 shows the load operation characteristics when the speed estimation calculation is performed using the method described in Patent Document 1. The primary resistance value R1 used in (Formula 1) and (Formula 7) is * is set to 0.5 times R1 of induction motor 1, induction motor 1 is operated at 1 Hz in the low speed range, and a load torque of up to 200% is applied in a ramp shape from point A to point B in the figure.

[0059] Rotational speed ω of induction motor 1 r and the estimated speed ω r ^^ are consistent, and the primary resistance setting R1 * However, the secondary resistance R2 used in (Equation 1) and (Equation 7) is * If there is an error in the sensorless control, it may become unstable.

[0060] FIG. 5 shows the secondary resistance setting R2 used in (Equation 1) and (Equation 7) for speed estimation calculation. * The load operating characteristics are shown in Fig. 1, where the secondary resistance value R2 of induction motor 1 is set to 0.5 times.

[0061] Rotational speed ω of induction motor 1 r is the steady-state speed estimate ω r ^ The torque τ and rotation speed ω of the induction motor 1 decrease from point B onward. r It can be seen that the vibration gradually increases. There was a problem with this type of vibration phenomenon.

[0062] This is because the speed estimation calculation shown in (Equation 1) uses only the voltage information of the m-axis, which causes the torque and rotation speed to vibrate. As a solution, the voltage command values ​​(v mc ** , v tc ** ) and current detection value (i mc , i tc ) to calculate the speed estimate using the power information.

[0063] The present invention can improve this vibration phenomenon. The speed estimation of the present invention will now be described.

[0064] FIG. 6 shows a block diagram of the speed / frequency / phase calculation unit 7a. The slip frequency calculation unit 7a1 calculates the q-axis current command value i q * , d-axis secondary magnetic flux command value φ 2d * Mutual inductance value M and secondary time constant T2 setting value T2* Using this, the slip frequency command value ω s * is calculated according to the above-mentioned (Equation 10).

[0065] In Patent Document 1, the estimated speed value ω r ^ In this embodiment, the speed estimate ω is calculated using the cross product of the power. r ^^ Calculate the following.

[0066] The power cross product calculation unit 7a2 calculates the voltage command value v mc ** , v tc ** and the current detection value i mc , i tc Using the power cross product E cp ^ is calculated according to (Equation 13).

[0067]

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[0068] The power cross product model calculation unit 7a3 calculates the m-axis and t-axis current detection values ​​i mc , i tc , the speed estimate ω r ^^ , Primary frequency command value ω1 * , Circuit parameters R2', L of induction motor 1 σ , M, L2, m-axis and t-axis magnetic flux command value φ m * , φ t * Using the cross product model value E cp * is calculated according to (Equation 14).

[0069]

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[0070] The subtraction unit 7a4 calculates the cross product value E cp^ and the cross product model value E cp * is input, and the deviation is ΔE cp The output is the deviation ΔE cp is input to the PI control calculation unit 7a5. The PI control calculation unit 7a5 calculates the deviation ΔE cp From the proportional gain of the speed estimation calculation and the integral gain of the speed estimation calculation, the speed estimation value ω r ^^ Calculate the following.

[0071]

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[0072] The adder 7a6 calculates the slip frequency command value ω s * and the estimated speed ω r ^^ is input, and the primary frequency command value ω1 is calculated using (Equation 16). * Output.

[0073]

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[0074] The phase estimation calculation unit 7a7 calculates the primary frequency command value ω1 * is input, and the phase estimate θ dc Output.

[0075] FIG. 7 shows the load operation characteristics according to this embodiment (the conditions used in FIG. 5 are set). By comparing the load characteristics shown in FIG. 5 and FIG. 7, the estimated speed value ω r ^^ There is no vibration phenomenon, and the effect is obvious.

[0076] In other words, by using the present invention, the error in the secondary resistance value R2 of the induction motor 1 (R2 *-R2) is the speed deviation (ω r * -ω r ) but it is possible to prevent oscillations in motor speed and torque.

[0077] In the above description, the power calculation and the power model calculation are performed using the voltage command value and the current detection value as examples of the output voltage and output current of the induction motor. The power calculation and the power model calculation may use the voltage detection value as the output voltage and the current detection value as the output current.

[0078] Here, a verification method in the case where this embodiment is adopted will be described with reference to FIG.

[0079] A voltage detector 21 and a current detector 22 are attached to a power conversion device 20 that drives the induction motor 1, and an encoder 23 is attached to the shaft of the induction motor 1.

[0080] In the first step, the mt-axis voltage, current, and magnetic flux calculation unit 24 calculates the three-phase AC voltage detection value (v uc , v vc , v wc ), three-phase AC current detection value (i uc , i vc , i wc ) and the encoder output position θ are input, and the vector voltage component v dc ^ , v qc ^ , vector current component i dc ^ , i qc ^ and the detected value ω obtained by differentiating the position θ rc , and the slip frequency estimate ω s ^ Calculate the following.

[0081] In the second step, the detected vector current component i dc ^ , i qc ^Using the circuit parameters of induction motor 1 (results of offline auto-tuning installed in the general-purpose inverter or design values), the estimated phase angle θ mt ^ From (Equation 17), the voltage components of the m-axis and t-axis are v mc ^ , v mc ^ From (Equation 18), the current component i mc ^ , i tc ^ From (Equation 19), the magnetic flux component φ m ^ , φ tc ^ are derived from (Equation 20), respectively.

[0082] In the power cross product calculation unit 25, the power cross product value E is calculated using (Formula 21) and (Formula 22) corresponding to (Formula 13) and (Formula 14). cp ^ _ est , E cp * _ est These E cp ^ _ est and E cp * _ est If they match, it becomes clear that the present invention is being adopted.

[0083]

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[0084]

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[0085]

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[0086]

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[0087]

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[0088]

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[0089] FIG. 9 is a configuration diagram of a speed / frequency / phase calculation unit 7b using the inner product of power in the second embodiment.

[0090] 10 is a configuration diagram of a power conversion device and an induction motor according to a second embodiment. In the first embodiment, the cross product of the power is used, particularly in the low speed range, but in this embodiment, speed estimation is performed using the inner product of the power in the medium to high speed range.

[0091] The speed / frequency / phase calculation unit 7b is a block corresponding to 7a in Fig. 1 (Fig. 6). In Fig. 9, 7b1, 7b6, and 7b7 are the same as 7a1, 7a6, and 7a7 in Fig. 6.

[0092] The power inner product calculation unit 7b2 calculates the m-axis and t-axis voltage command values ​​v mc ** , v tc ** and the current detection value i mc , i tc Using this, the inner product value of the power E dp ^ is calculated according to (Equation 23).

[0093]

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[0094] The power dot product model calculation unit 7b3 calculates the m-axis and t-axis current detection values ​​i mc , i tc , the speed estimate ω r ^^^, the circuit parameters of induction motor 1 (R1 * , R2 ’* , L σ , M * , L2 * ), m-axis and t-axis magnetic flux command values ​​φ m * , φ t * Using the dot product model value E dp * is calculated according to (Equation 24).

[0095]

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[0096] The subtraction unit 7b4 calculates the inner product value E dp ^ and the inner product model value E dp * Enter the deviation ΔE dp The deviation ΔE is output. dp is input to the PI control calculation unit 7b5. The speed estimated value ω r ^^^ The calculation of this PI control calculation unit 7b5 is similar to (Formula 15) in the first embodiment.

[0097] In (Equation 24), the velocity component ω r ^^^ The second term, which includes the leakage inductance value L σ and its setting value L σ * Therefore, according to this embodiment, the sensitivity to the leakage inductance value is low in the medium to high speed range, and stable and highly accurate speed control can be realized. EXAMPLES

[0098] 11 is a configuration diagram of a speed / frequency / phase calculation unit 7c in the embodiment 3. In the embodiment 1, the speed estimation method uses the cross product of power especially in the low speed range, but in the present embodiment, the speed estimation method uses the cross product of power in the low speed range and the inner product of power in the medium to high speed range.

[0099] The speed / frequency / phase calculation unit 7c is a block corresponding to 7a in Fig. 1 (Fig. 6). In Fig. 11, 7c1, 7c6, and 7c7 are the same as 7a1, 7a6, and 7a7 in Fig. 6.

[0100] The speed estimation calculation unit 7c8 using the cross product of the power is a PI control calculation unit 7a5 shown in FIG. r ^^ The speed estimation calculation unit 7c9 using the inner product of the power outputs the output value ω r ^^^ Output.

[0101] The switching calculation unit 7c10 calculates the speed command value ω r * Based on this, the speed estimate ω r ^^ In the medium to high speed range, the estimated speed value ω r ^^^ Select one of them and set it to ω r ^^^^ The output is as follows:

[0102] The low speed range and the medium to high speed range are determined by the speed command value ω r * If the absolute value of is less than about 10% of the rated speed, it is considered to be in the low speed range, and if it is more than about 10%, it is considered to be in the medium to high speed range.

[0103] Alternatively, by comparing the voltage drop related to the sum of the primary resistance value and the converted secondary resistance value with the voltage drop related to the back electromotive force, if (Equation 25) holds, it can be determined that the low speed range exists, and otherwise it can be determined that the medium to high speed range exists.

[0104]

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[0105] As in this embodiment, by switching the speed estimation value between the low speed range and the high speed range, it is possible to realize stable and highly accurate speed control in the entire speed range. EXAMPLES

[0106] FIG. 12 is a configuration diagram of a fourth embodiment having a power conversion device, an induction motor, and an IOT (Internet of Things) controller.

[0107] In the first to third embodiments, the circuit parameters of the induction motor 1 are set in a controller (such as a microcomputer) of a power converter.

[0108] In this embodiment, the state quantity of the control is fed back to an IOT controller, which is a higher-level external device, and the machine-learned circuit parameters are reset in the controller, which is the control unit of the power converter.

[0109] Induction motor 1 to coordinate conversion unit 6, speed / frequency / phase calculation unit 7a, and reference phase calculation unit 8 to coordinate conversion unit 15 in Fig. 12 are the same as those in Fig. 1. Reference numeral 16 denotes an IOT controller that executes machine learning.

[0110] In this embodiment, the voltage command value v mc ** , v tc ** and the current detection value i mc , i tc , the speed estimate ω r ^^ , slip frequency command value ω s * The circuit parameters (R1 * , R2 * , L σ * , M * , L2 * ) in the controller which is the control section of the power converter 2.

[0111] By using this embodiment, it is possible to realize more stable and highly accurate control characteristics, similar to the first embodiment. EXAMPLES

[0112] FIG. 13 is a configuration diagram of a fifth embodiment having a power conversion device, an induction motor, and a device such as a personal computer, a tablet, or a smartphone.

[0113] This embodiment is applied to an induction motor drive system. In Fig. 13, an induction motor 1, a control unit of a power conversion device, etc. are the same as those in Fig. 1.

[0114] Induction motor 1, which is a component of Fig. 1, is driven by power conversion device 20. In power conversion device 20, coordinate conversion unit 5, coordinate conversion unit 6, speed / frequency / phase calculation unit 7a, and reference phase calculation unit 8 to coordinate conversion unit 15 in Fig. 1 are implemented as software 20a, and power converter 2, DC power supply 3, and current detector 4 in Fig. 1 are implemented as hardware.

[0115] In addition, the digital operator 20b, a personal computer 28, a tablet 29, a smartphone 30, or other higher-level device can control the "low-speed range / medium-high-speed range switching frequency 26, ω chg ", ω which is the control response of speed estimation 27 c " can be set and changed.

[0116] If this embodiment is applied to an induction motor drive system, stable and highly accurate control characteristics can be realized in speed sensorless vector control. chg ", "ω c " may be configured on a fieldbus such as a programmable logic controller, a local area network connecting to a computer, or an IOT controller.

[0117] Furthermore, although this embodiment is disclosed using embodiment 1, embodiments 2 to 4 may also be used.

[0118] In the above-described Examples 1 to 5, the cross product value Ecp ^ (Equation 13) and the cross product model value E cp * In (Equation 14), the current detection value i mc , i mc was used, but the current command value i m * , i t * may be substituted.

[0119] Also, the inner product value of the power E dp ^ (Equation 23) and the inner product model value E dp * In equation 24, the current detection value i mc , i tc was used, but the current command value i m * , i t * may be substituted.

[0120] Furthermore, in the first to fifth embodiments, the current command value i m * , i t * and the current detection value i mc , i tc Voltage correction value Δv mc , Δv tc The voltage correction value is added to the voltage reference value of the vector control (Equation 9). m * , i t * and the current detection value i mc , i tc As shown in (Equation 26), the voltage command value v mc *** , v mt *** It is also possible to perform the following calculation.

[0121]

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[0122] Or the current command value i m * , i t * and the current detection value i mc , i tc The intermediate current command value i shown in (Equation 27) used for vector control calculation is m ** , i t ** and calculate the speed estimate ω r ^ , Primary frequency command value ω1 * And, a vector control calculation shown in (Formula 28) may be performed using the circuit parameters of the induction motor 1.

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[0125] Or the current command value i m * , i t * and the current detection value imc , i tc The voltage correction value Δv of the proportional calculation component of the m axis used for vector control calculation is m_p * , the voltage correction value Δv of the integral calculation component of the m axis m_i * , the voltage correction value Δv of the proportional calculation component of the t axis t_p * , voltage correction value Δv of the integral calculation component of the t axis t_i * is created using (Equation 29), and the speed estimate ω r ^^ , Primary frequency command value ω1 * A vector control calculation using the circuit parameters of the induction motor 1 may be performed as shown in (Formula 30). p_m3 : Proportional gain of m-axis current control, K im_3 : Integral gain of m-axis current control, K p_t3 : Proportional gain of current control on the t axis, K it_3 :t-axis current control integral gain

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[0128] In the first to fifth embodiments, the switching elements constituting the power converter 2 may be Si (silicon) semiconductor elements or wide band gap semiconductor elements such as SiC (silicon carbide) and GaN (gallium nitride). [Explanation of symbols]

[0129] 1...induction motor, 2...power converter, 3...DC power supply, 4...current detector, 5...coordinate conversion section, 6...coordinate conversion section, 7a, 7b, 7c...speed, frequency, and phase calculation section, 8...reference phase calculation section, 9...excitation current and magnetic flux setting section, 10...speed control calculation section, 11...coordinate conversion section, 12...coordinate conversion section, 13...MT axis vector control calculation section, 14...coordinate conversion section, 15...coordinate conversion section, 20...power conversion device, 20a...software for power conversion device, 20b...digital operator for power conversion device, 21...voltage detector, 22...current detector, 23...encoder, 24...calculation section for voltage, current, and magnetic flux of MT axis components, 25...calculation section for cross product of power, 26...switching frequency for specified low speed range / medium-high speed range, 27...control response of speed estimation calculation, 28...personal computer, 29...tablet, 30...smartphone, i d * …d-axis current command value, i q * …q-axis current command value, i dc …d-axis current detection value, i qc …q-axis current detection value, v dc ** …d-axis voltage command value, v qc ** …q-axis voltage command value, φ 2d * …d-axis secondary magnetic flux command value, φ 2q * …q-axis secondary magnetic flux command value, i m * …m-axis current command value, i t * …t-axis current command value, i mc …current detection value of m axis, i tc …t-axis current detection value, v mc ** , v mc *** , v mc **** , v mc **** …m-axis voltage command value, v tc ** , v tc *** , v tc **** , v mc **** …t-axis voltage command value, φ m* …m-axis magnetic flux command value, φ t * …t-axis magnetic flux command value, ω r * ...Speed ​​command value, ω r …Rotational speed of induction motor 1, ω r ^ , ω r ^^ , ω r ^^^ , ω r ^^^^ …speed estimate, ω s * …Slip frequency command value, ω1 * …Primary frequency command value, θ mt …Phase angle between d-axis and m-axis, θ dc …phase estimate, E cp ^…cross product value of power, E cp *…Power cross product model value, E dp ^…Power dot product, E dp *…Power dot product model value, v u , v v , v v …Three-phase AC voltage command value, i u , i v , i v …Three-phase AC current, i uc , i vc , i vc …Three-phase AC current detection value

Claims

1. a power converter that outputs a signal to the induction motor to vary an output frequency, an output voltage, and an output current of the induction motor; A control unit that controls the power converter, The control unit is The output voltage on a control axis in a rotating coordinate system that is a direction of the primary current and a direction perpendicular to the primary current. Calculating power from the output current; Calculating a power model from the output current and circuit parameters in the control axis; Computing a speed estimate from the power and the power model; Calculating power from a voltage command value and a current detection value in the control axis; Calculating a feedback voltage component so that the m-axis and t-axis current detection values ​​follow the m-axis and t-axis current command values ​​which are the control axes; A power conversion device that calculates the voltage command value from the feedback voltage component.

2. 2. The power conversion device according to claim 1, The control unit is A feedforward voltage component is calculated from the m-axis and t-axis current command values ​​or current detection values, the speed estimation value or speed command value, the primary frequency command value, the resistance value and inductance value which are circuit parameters of the induction motor, and the m-axis and t-axis magnetic flux command values; The voltages of the m-axis and t-axis are determined from the feedforward voltage component and the feedback voltage component. A power conversion device that calculates the power value.

3. A power converter that outputs a signal to the induction motor to vary an output frequency, an output voltage, and an output current of the induction motor; A control unit that controls the power converter, The control unit is The output voltage on a control axis in a rotating coordinate system that is a direction of the primary current and a direction perpendicular to the primary current. Calculating power from the output current; Calculating a power model from the output current and circuit parameters in the control axis; Computing a speed estimate from the power and the power model; The power is the cross product of the powers, the power model is a cross product model of power; the control unit generates a first voltage drop model obtained by multiplying a sum of a squared value of a t-axis current detection value or a current command value and a squared value of an m-axis current detection value or a current command value by a primary frequency command and a leakage inductance value of an induction motor; a second voltage drop model obtained by adding a value obtained by multiplying a t-axis current detection value or a current command value by a t-axis magnetic flux command value and a value obtained by multiplying an m-axis current detection value or a current command value by an m-axis magnetic flux command value, and multiplying the sum by a ratio of a speed estimation value, a mutual inductance value, and a secondary inductance value; a third voltage drop model is calculated by subtracting a value obtained by multiplying the m-axis current detection value or current command value by the t-axis magnetic flux command value from a value obtained by multiplying the t-axis current detection value or current command value by the m-axis magnetic flux command value, and multiplying the subtracted value by a ratio of the secondary resistance value and the mutual inductance value converted into the primary side; a power conversion device that calculates the cross product model of power by multiplying an added value of the first voltage drop model, the second voltage drop model, and the third voltage drop model by −1.

4. A power converter that outputs a signal to the induction motor to vary an output frequency, an output voltage, and an output current of the induction motor; A control unit that controls the power converter, The control unit is The output voltage on a control axis in a rotating coordinate system that is a direction of the primary current and a direction perpendicular to the primary current. Calculating power from the output current; Calculating a power model from the output current and circuit parameters in the control axis; Computing a speed estimate from the power and the power model; The power is a dot product of powers, the power model is a dot product model of power; The control unit is a fourth voltage drop model obtained by multiplying a circuit parameter by the sum of a squared value of a t-axis current detection value or a current command value and a squared value of an m-axis current detection value or a current command value; a fifth voltage drop model obtained by multiplying the m-axis current detection value or current command value by the t-axis magnetic flux command value, subtracting the m-axis current detection value or current command value by the t-axis magnetic flux command value from the t-axis current detection value or current command value, and multiplying the subtracted value by a ratio of the speed estimation value, the mutual inductance value, and the secondary inductance value; a sixth voltage drop model is calculated by multiplying the t-axis current detection value or current command value by the t-axis magnetic flux command value, adding the m-axis current detection value or current command value to the m-axis magnetic flux command value, and multiplying the sum by a ratio of the secondary resistance value converted to the primary side and the mutual inductance value; a power conversion device that calculates the inner product model of power by adding the fourth voltage drop model, the fifth voltage drop model, and the sixth voltage drop model.

5. A power converter that outputs a signal to the induction motor to vary an output frequency, an output voltage, and an output current of the induction motor; A control unit that controls the power converter, The control unit is The output voltage on a control axis in a rotating coordinate system that is a direction of the primary current and a direction perpendicular to the primary current. Calculating power from the output current; Calculating a power model from the output current and circuit parameters in the control axis; Computing a speed estimate from the power and the power model; The cross product of the power obtained by subtracting the value obtained by multiplying the m-axis voltage command value by the m-axis current detection value or current command value from the value obtained by multiplying the m-axis voltage command value, which is the control axis, by the t-axis current detection value or current command value, and the deviation of the cross product model of the power are calculated for proportional control and integral control, or the value obtained by multiplying the m-axis voltage command value by the m-axis current detection value or current command value and the voltage command A power conversion device that calculates the deviation of the power inner product model, obtained by adding the value multiplied by the t-axis current detection value or current command value to the power inner product, and calculates a speed estimate value by performing proportional control and integral control.

6. a power converter that outputs a signal to the induction motor to vary an output frequency, an output voltage, and an output current of the induction motor; A control unit that controls the power converter, The control unit is The output voltage on a control axis in a rotating coordinate system that is a direction of the primary current and a direction perpendicular to the primary current. Calculating power from the output current; Calculating a power model from the output current and circuit parameters in the control axis; Computing a speed estimate from the power and the power model; If the induction motor is in a low speed range, the deviation between the cross product of the power and the cross product model is calculated; If the induction motor is in the mid-high range, calculate the inner product of the power and the deviation of the inner product model; A power conversion device that performs proportional control and integral control on one of the deviations to calculate the speed estimate value.

7. 7. The power conversion device according to claim 6, The control unit is A switching frequency for switching between the low speed range and the medium / high speed range control, or a control response of the proportional control or the integral control is set, A power conversion device in which the switching frequency or the control response can be changed from an external device.

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