control device

Abstract

To improve the accuracy in torque control of an induction machine.SOLUTION: A control device 100 comprises a control constant setting unit 106. The control constant setting unit 106 comprises: a current pattern generation unit 1021 that generates a DC current command indicating a first DC current in an ON1 state of a selection signal Select, and generates a DC current command for indicating a second DC current in an ON2 state of the selection signal Select; a current control unit 1022 that generates such a measurement voltage command vm* that the current value of a current i flowing in an induction machine 1 follows the DC current command and a phase angle of the current i follows a DC phase angle command; a rotation coordinate conversion unit 1023 that performs rotation coordinate conversion on to a secondary magnetic flux φ2 of the induction machine 1 and outputs a current axis secondary magnetic flux φ2v; and a constant calculation unit 1025 that calculates a correction voltage measurement value Vem and a primary resistance measurement value R1m on the basis of the current axis secondary magnetic flux φ2v in each of the ON1 state and the ON2 state.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a control device for torque control of an induction motor. [Background technology]

[0002] As an example of a control device for controlling an induction motor that drives an electric vehicle, Patent Document 1 discloses a control device that calculates the rotational speed of the induction motor and controls the torque of the induction motor. With such a control device, the induction motor can be controlled according to a torque command without using a speed sensor.

[0003] Figure 6 shows an example of the configuration of a control device 10 that controls the induction machine 1 by calculating its rotational speed through the calculations described above.

[0004] The control device 10 shown in Figure 6 comprises a PWM (Pulse Width Modulation) inverter 11, a current detector 12a, a voltage correction unit 13a, a secondary magnetic flux calculation unit 14a, a speed calculation unit 15, an induction motor control unit 16a, and a PWM signal generation unit 17a.

[0005] The PWM inverter 11 consists of multiple switching elements and controls the on / off state of the multiple switching elements based on the switching signal Sw output from the PWM signal generation unit 17a, thereby pulse-width modulated the output voltage Vdc of the DC voltage source 2 and supplying an AC voltage to the induction motor 1.

[0006] The current detector 12a detects the current i flowing through the induction motor 1 and outputs the detection result to the voltage correction unit 13a, the secondary magnetic flux calculation unit 14a, the velocity calculation unit 15, and the induction motor control unit 16a.

[0007] The voltage correction unit 13a corrects the voltage drop (equivalent to ON voltage, equivalent to dead time voltage) due to the switching elements of the PWM inverter 11 and estimates the output voltage of the PWM inverter 11. The voltage correction unit 13a estimates the output voltage of the PWM inverter 11 based on the switching signal Sw, the output voltage Vdc of the DC voltage source 2, the current i detected by the current detector 12a, and the correction voltage setting value Ve, which is the setting value of the correction voltage for correcting the voltage corresponding to the output of the PWM inverter 11. Specifically, the voltage correction unit 13a obtains the voltage v corresponding to the output of the PWM inverter 11 from the product of the output voltage Vdc of the DC voltage source 2 and the duty cycle of the switching signal Sw. Then, if the polarity of the current i is positive, the voltage correction unit 13a obtains the estimated voltage vin from vin = v - Ve. Also, if the polarity of the current i is negative, the voltage correction unit 13a obtains the estimated voltage vin from vin = v + Ve.

[0008] The voltage correction unit 13a outputs the estimated output voltage result as the estimated voltage vin to the secondary magnetic flux calculation unit 14a.

[0009] The secondary magnetic flux calculation unit 14a calculates the secondary magnetic flux φ2 of the induction motor 1 according to the following equation (1), based on the current i output from the current detector 12a, the estimated voltage vin output from the voltage correction unit 13a, and the primary resistance setting value R1, which is the setting value of the primary resistance of the induction motor 1.

[0010]

number

[0011] In equation (1), M is the mutual inductance of the induction machine 1, L1 is the primary self-inductance of the induction machine 1, and L2 is the secondary self-inductance of the induction machine 1.

[0012] The secondary magnetic flux calculation unit 14a outputs the calculation result of the secondary magnetic flux φ2 to the velocity calculation unit 15.

[0013] Based on the current i output from the current detector 12a and the secondary magnetic flux φ2 output from the secondary magnetic flux calculation unit 14a, the speed calculation unit 15 calculates the rotational speed ωmc of the induction machine 1 according to the following formula (2).

[0014]

Equation

[0015] In formula (2), ωf2 is the rotational speed of the secondary magnetic flux φ2, R2 is the secondary resistance of the induction machine 1, and the operator? represents the cross product.

[0016] The speed calculation unit 15 outputs the calculation result of the rotational speed ωmc to the induction machine control unit 16a.

[0017] Based on the current i output from the current detector 12a and the rotational speed ωmc output from the speed calculation unit 15, the induction machine control unit 16a instructs the control voltage command vc of the output voltage of the PWM inverter 11 such that the torque of the induction machine 1 follows the torque command TqRef. * Generate and output it to the PWM signal generation unit 17a.

[0018] Based on the control voltage command vc output from the induction machine control unit 16a * The PWM signal generation unit 17a generates a switching signal Sw for controlling the switching elements of the PWM inverter 11 and outputs it to the PWM inverter 11 and the voltage correction unit 13a.

Prior Art Documents

Patent Documents

[0019]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0020] In the control device 10 shown in Figure 6, variations occur in the actual correction voltage due to individual differences in the switching elements constituting the PWM inverter 11. Furthermore, it is difficult to measure the correction voltage accurately due to voltage and current lags or overshoots in the switching elements. In addition, the primary resistance of the induction motor 1 fluctuates depending on the temperature of the induction motor 1.

[0021] Therefore, in the control device 10 shown in Figure 6, setting errors may occur in the correction voltage set value Ve and the primary resistance set value R1. If setting errors occur in the correction voltage set value Ve and the primary resistance set value R1, errors will also occur in the calculation of the estimated voltage vin, secondary magnetic flux φ2, and rotational speed ωmc, making it impossible to accurately control the torque of the induction machine 1.

[0022] In view of the above-mentioned problems, the object of the present invention is to provide a control device that can improve the accuracy of torque control of an induction motor. [Means for solving the problem]

[0023] (1) The control device according to the present disclosure is a control device for an induction machine, comprising: a PWM inverter equipped with a switching element that pulse-width modulates the output voltage of a DC voltage source to supply an AC voltage to the induction machine; a PWM signal generation unit that outputs a switching signal to the PWM inverter to control the switching element based on a voltage command; a current detector that detects the current flowing through the induction machine; a voltage correction unit that calculates an estimated voltage by estimating the output voltage of the PWM inverter based on the switching signal, the output voltage of the DC voltage source, the current detected by the current detector, and a correction voltage for correcting the voltage corresponding to the output of the PWM inverter; a secondary magnetic flux calculation unit that calculates the secondary magnetic flux of the induction machine based on the primary resistance of the induction machine, the estimated voltage, and the current detected by the current detector; a speed calculation unit that calculates the rotational speed of the induction machine based on the secondary magnetic flux and the current detected by the current detector; and a PWM inverter that outputs a torque from the induction machine according to a torque command based on the current detected by the current detector and the rotational speed. The induction motor includes an induction motor control unit that generates a control voltage command that indicates the output voltage of the motor, a selection signal generation unit that generates a selection signal having a first state, a second state, and a third state, and a control constant setting unit that determines the correction voltage measurement value, which is the measurement value of the correction voltage, and the primary resistance measurement value, which is the measurement value of the primary resistance, wherein the control constant setting unit generates a DC current command that indicates a first DC current in the first state, and generates a DC current command that indicates a second DC current in the second state, and the current that flows through the induction motor The system comprises: a current control unit that generates a measuring voltage command that instructs the output voltage of the PWM inverter such that the current value follows the DC current command and the phase angle of the current flowing through the induction motor follows the DC phase angle command; a rotational coordinate transformation unit that performs a rotational coordinate transformation in the axial direction of the DC phase angle command with respect to the secondary magnetic flux and outputs the current axis secondary magnetic flux; and a constant calculation unit that calculates the corrected voltage measurement value and the primary resistance measurement value based on the current axis secondary magnetic flux output from the rotational coordinate transformation unit in the first state and the second state, respectively. The selection signal generation unit transitions the selection signal from the third state to the first state in response to the input of a predetermined command, transitions it from the first state to the second state after a first predetermined time has elapsed, transitions it from the second state to the third state after a second predetermined time has elapsed, and the constant calculation unit outputs a first data selector that outputs a first time point current axis secondary flux and a second time point current axis secondary flux based on the selection signal, the first predetermined time, and the current axis secondary flux, a second data selector that outputs a third time point current axis secondary flux and a fourth time point current axis secondary flux based on the selection signal, the second predetermined time, and the current axis secondary flux, and the correction voltage at the first predetermined time and The system comprises: a first auxiliary calculator that calculates a first error value which is an error value caused by the primary resistance; a second auxiliary calculator that calculates a second error value which is an error value caused by the correction voltage and the primary resistance at the second predetermined time, based on the third time current axis secondary flux, the fourth time current axis secondary flux, and the second predetermined time; an error calculator that calculates a correction voltage error value and a primary resistance error value based on the first error value, the second error value, the first DC current, and the second DC current; a first corrector that calculates the correction voltage measurement value based on a correction voltage setting value which is a preset setting value of the correction voltage and the correction voltage error value; and a second corrector that calculates the primary resistance measurement value based on a primary resistance setting value which is a preset setting value of the primary resistance and the primary resistance error value. ru.

[0026] ( 2 ) ( 1 In the control device described in ( ), the first data selector outputs the relative value of the current axis secondary magnetic flux at half the time of the first predetermined time as the current axis secondary magnetic flux at the time when the selection signal transitions from the third state to the first state, and outputs the relative value of the current axis secondary magnetic flux at the time when the first predetermined time has elapsed as the current axis secondary magnetic flux at the second time.

[0027] ( 3 ) ( 1 )or( 2 In the control device described in ( ), the second data selector outputs the relative value of the current axis secondary magnetic flux at half the second predetermined time as the current axis secondary magnetic flux at the time when the selection signal transitions from the first state to the second state, and outputs the relative value of the current axis secondary magnetic flux at the time when the second predetermined time has elapsed as the current axis secondary magnetic flux at the fourth predetermined time.

[0028] ( 4 ) (1) to ( 3 In the control device described in any one of the above, the control constant setting unit sets the correction voltage measurement value as the correction voltage in the third state.

[0029] ( 5 ) (1) to ( 4 In the control device described in any one of the above, the control constant setting unit sets the primary resistance measurement value as the primary resistance in the third state. [Effects of the Invention]

[0030] The control device according to the present invention can improve the accuracy of torque control of induction machines. [Brief explanation of the drawing]

[0031] [Figure 1] This figure shows an example configuration of a control device according to one embodiment of the present invention. [Figure 2] This figure shows an example of the state transition of the selection signal generated by the selection signal generation unit shown in Figure 1. [Figure 3] This figure shows an example of the configuration of the control constant measurement unit shown in Figure 1. [Figure 4] This figure shows an example of a DC current command output by the current pattern generation unit shown in Figure 3. [Figure 5] Figure 3 shows an example of the configuration of the constant calculation unit. [Figure 6] This figure shows an example of a conventional control device configuration. [Modes for carrying out the invention]

[0032] Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

[0033] Figure 1 shows an example of the configuration of a control device 100 according to one embodiment of the present invention. The control device 100 according to this embodiment controls the torque of the induction motor 1 that drives the electric vehicle. In Figure 1, components similar to those in Figure 6 are denoted by the same reference numerals and their descriptions are omitted.

[0034] The control device 100 shown in Figure 1 comprises a PWM inverter 11, a current detector 12, a voltage correction unit 13, a secondary magnetic flux calculation unit 14, a speed calculation unit 15, an induction motor control unit 16, a PWM signal generation unit 17, a selection signal generation unit 101, a control constant measurement unit 102, a first selection unit 103, a second selection unit 104, and a third selection unit 105. The control constant measurement unit 102, the first selection unit 103, the second selection unit 104, and the third selection unit 105 constitute a control constant setting unit 106.

[0035] The current detector 12 detects the current i flowing through the induction motor 1 and outputs the detection result to the voltage correction unit 13, the secondary magnetic flux calculation unit 14, the velocity calculation unit 15, the induction motor control unit 16, and the control constant measurement unit 102.

[0036] The voltage correction unit 13 estimates the estimated voltage vin based on the switching signal Sw, the output voltage Vdc of the DC voltage source 2, the current i detected by the current detector 12, and the correction voltage VeC output from the second selection unit 104, which will be described later. The method for estimating the estimated voltage vin by the voltage correction unit 13 is the same as that of the voltage correction unit 13a. However, the voltage correction unit 13 corrects the voltage v, which corresponds to the output of the PWM inverter 11 obtained from the product of the output voltage Vdc of the DC voltage source 2 and the duty cycle of the switching signal Sw, using the correction voltage VeC instead of the correction voltage setting value Ve, which is a preset correction voltage setting value. The voltage correction unit 13 outputs the obtained estimated voltage vin to the secondary magnetic flux calculation unit 14.

[0037] The secondary magnetic flux calculation unit 14 calculates the secondary magnetic flux φ2 of the induction motor 1 based on the current i output from the current detector 12, the estimated voltage vin output from the voltage correction unit 13, and the primary resistance R1C output from the third selection unit 105, which will be described later. The method of calculating the secondary magnetic flux φ2 by the secondary magnetic flux calculation unit 14 is the same as that of the secondary magnetic flux calculation unit 14a. However, the secondary magnetic flux calculation unit 14 uses the primary resistance R1C instead of the primary resistance setting value R1, which is a preset setting value for the primary resistance of the induction motor 1. The secondary magnetic flux calculation unit 14 outputs the calculated secondary magnetic flux φ2 to the speed calculation unit 15 and the control constant measurement unit 102. The secondary magnetic flux φ2 output to the speed calculation unit 15 is used to calculate the rotational speed ωmc.

[0038] The induction motor control unit 16, based on the current i output from the current detector 12 and the rotational speed ωmc output from the speed calculation unit 15, issues a control voltage command vc that instructs the output voltage of the PWM inverter 11 such that the torque of the induction motor 1 conforms to the torque command TqRef. * It generates and outputs to the first selection unit 103.

[0039] The PWM signal generation unit 17 receives the voltage command vv output from the first selection unit 103, which will be described later. *Based on this, a switching signal Sw is generated and output to the PWM inverter 11 and the voltage correction unit 13. The PWM inverter 11 controls the on / off state of the switching elements based on the switching signal Sw output from the PWM signal generation unit 17, thereby pulse-width modulating the output voltage Vdc of the DC voltage source 2 and supplying AC voltage to the induction motor 1.

[0040] The selection signal generation unit 101 receives a measurement command Run (a predetermined command) and generates a selection signal Select to control the measurement of the correction voltage VeC and the primary resistance R1C in accordance with the transition of the measurement command Run. Figure 2 shows an example of the state transition of the selection signal Select.

[0041] As shown in Figure 2, the selection signal generator 101 generates a selection signal Select having an ON1 state (first state), an ON2 state (second state), and an OFF state (third state). When the measurement command Run is in the OFF state, the selection signal generator 101 keeps the selection signal Select in the OFF state. When the measurement command Run transitions from the OFF state to the ON state, the selection signal generator 101 transitions the selection signal Select from the OFF state to the ON1 state. After transitioning the selection signal Select to the ON1 state, the selection signal generator 101 transitions the selection signal Select from the ON1 state to the ON2 state after a time Tm1 (first predetermined time) has elapsed. Then, after transitioning the selection signal Select to the ON2 state, the selection signal generator 101 transitions the selection signal Select from the ON2 state to the OFF state after a time Tm2 (second predetermined time) has elapsed.

[0042] Referring again to Figure 1, the selection signal generation unit 101 outputs the generated selection signal Select to the control constant measurement unit 102, the first selection unit 103, the second selection unit 104, and the third selection unit 105.

[0043] The control constant measurement unit 102 receives the current i output from the current detector 12, the secondary magnetic flux φ2 output from the secondary magnetic flux calculation unit 14, the selection signal Select output from the selection signal generation unit 101, the correction voltage set value Ve, and the primary resistance set value R1, and measures the correction voltage measurement value Vem which is the measured value of the correction voltage VeC, the primary resistance measurement value R1m which is the measured value of the primary resistance R1C, and the measurement voltage command vm for measuring the correction voltage measurement value Vem and the primary resistance measurement value R1m. * and generates them.

[0044] The control constant measurement unit 102 generates the measurement voltage command vm that instructs the output voltage of the PWM inverter 11 when the selection signal Select is in the ON1 state and the ON2 state. * Specifically, when the selection signal Select is in the ON1 state, the control constant measurement unit 102 generates the measurement voltage command vm such that the direct current (first direct current) of the current value I1 flows through the induction machine 1, and when the selection signal Select is in the ON2 state, the direct current (second direct current) of the current value I2 flows through the induction machine 1. Then, the control constant measurement unit 102 obtains the correction voltage measurement value Vem and the primary resistance measurement value R1m based on the secondary magnetic flux φ2 of the induction machine 1 when the selection signal Select is in the ON1 state and the ON2 state. *

[0045] The control constant measurement unit 102 outputs the measurement voltage command vm * to the first selection unit 103, outputs the correction voltage measurement value Vem to the second selection unit 104, and outputs the primary resistance measurement value R1m to the third selection unit 105. Details of the configuration and operation of the control constant measurement unit 102 will be described later.

[0046] The first selection unit 103 receives the control voltage command vc * output from the induction machine control unit 16, the selection signal Select output from the selection signal generation unit 101, and the measurement voltage command vm * output from the control constant measurement unit 102, and outputs the voltage command vv * to the PWM signal generation unit 17. The first selection unit 103 outputs the measurement voltage command vm when the selection signal Select is in the ON1 state and the ON2 state.* Voltage command vv * It outputs as follows, and when the selection signal Select is OFF, the control voltage command vc * Voltage command vv * Output as follows.

[0047] The second selection unit 104 receives the selection signal Select output from the selection signal generation unit 101, the correction voltage measurement value Vem output from the control constant measurement unit 102, and the correction voltage set value Ve, and outputs the correction voltage VeC to the voltage correction unit 13. When the selection signal Select is in the ON1 and ON2 states, the second selection unit 104 outputs the correction voltage set value Ve as the correction voltage VeC, and when the selection signal Select is in the OFF state, it outputs the correction voltage measurement value Vem as the correction voltage VeC. In other words, when the selection signal Select is in the OFF state, the second selection unit 104 sets the correction voltage measurement value Vem as the correction voltage VeC.

[0048] The third selection unit 105 receives the selection signal Select output from the selection signal generation unit 101, the primary resistance measurement value R1m output from the control constant measurement unit 102, and the primary resistance set value R1, and outputs the primary resistance R1C to the secondary magnetic flux calculation unit 14. When the selection signal Select is in the ON1 and ON2 states, the third selection unit 105 outputs the primary resistance set value R1 as the primary resistance R1C, and when the selection signal Select is in the OFF state, it outputs the primary resistance measurement value R1m as the primary resistance R1C. In other words, when the selection signal Select is in the OFF state, the third selection unit 105 sets the primary resistance measurement value R1m as the primary resistance R1C.

[0049] As described above, the control constant measurement unit 102, the first selection unit 103, the second selection unit 104, and the third selection unit 105 constitute the control constant setting unit 106. Therefore, the control constant setting unit 106 instructs the output voltage of the PWM inverter 11 to set a measurement voltage command vm such that when the selection signal Select is ON1, a DC current of current value I1 flows to the induction motor 1, and when the selection signal Select is ON2, a DC current of current value I2 flows to the induction motor 1. * Voltage command vv *The PWM signal is output to the PWM signal generation unit 17. The control constant setting unit 106 determines the correction voltage measurement value Vem and the primary resistance measurement value R1m based on the secondary magnetic flux φ2 of the induction motor 1 in the ON1 state and ON2 state. The control constant setting unit 106 also sets the correction voltage measurement value Vem as the correction voltage VeC when the selection signal Select is OFF. The control constant setting unit 106 also sets the primary resistance measurement value R1m as the primary resistance R1C when the selection signal Select is OFF.

[0050] In the control device 100 shown in Figure 1, before starting torque control of the induction motor 1, the measurement command Run is transitioned from the OFF state to the ON state. By transitioning the measurement command Run from the OFF state to the ON state, as described above, the selection signal Select transitions from the OFF state to the ON1 state, and after time Tm1 has elapsed, it transitions from the ON1 state to the ON2 state, and after time Tm2 has elapsed, it transitions from the ON2 state to the OFF state. The control constant measurement unit 102 determines the corrected voltage measurement value Vem and the primary resistance measurement value R1m based on the secondary magnetic flux φ2 in the ON1 state and the ON2 state.

[0051] When the selection signal Select transitions from the ON2 state to the OFF state, torque control of induction motor 1 is started. The second selection unit 104 outputs the calculated correction voltage measurement value Vem as the correction voltage VeC to the voltage correction unit 13. The third selection unit 105 outputs the calculated primary resistance measurement value R1m as the primary resistance R1C to the secondary magnetic flux calculation unit 14. The voltage correction unit 13 calculates the estimated voltage vin using the correction voltage VeC (correction voltage measurement value Vem) output from the second selection unit 104. The secondary magnetic flux calculation unit 14 calculates the secondary magnetic flux φ2 using the primary resistance R1C (primary resistance measurement value R1m) output from the third selection unit 105.

[0052] In this way, based on the secondary magnetic flux φ2 when the selection signal Select is ON1 and ON2, the corrected voltage measurement Vem and primary resistance measurement R1m are determined. When the selection signal Select is OFF, the determined corrected voltage measurement Vem and primary resistance measurement R1m are used as the corrected voltage VeC and primary resistance R1C, respectively. This reduces the calculation errors of the estimated voltage vin, secondary magnetic flux φ2, and rotational speed ωmc, thereby improving the accuracy of torque control of the induction motor 1.

[0053] Next, the configuration of the control constant measurement unit 102 will be explained with reference to Figure 3.

[0054] As shown in Figure 3, the control constant measurement unit 102 comprises a current pattern generation unit 1021, a current control unit 1022, a rotation coordinate transformation unit 1023, and a constant calculation unit 1025.

[0055] The current pattern generation unit 1021 receives a selection signal Select and predetermined current values ​​I1 and I2 as inputs and generates a DC current command Idc that instructs the DC current to flow through the induction motor 1.

[0056] Figure 4 shows an example of a DC current command Idc generated by the current pattern generation unit 1021. As shown in Figure 4, when the selection signal Select is ON1, the current pattern generation unit 1021 generates a DC current command Idc that instructs the induction motor 1 to flow a DC current with current value I1 (the first DC current). When the selection signal Select is ON2, the current pattern generation unit 1021 generates a DC current command Idc that instructs the induction motor 1 to flow a DC current with current value I2 (the second DC current). When the selection signal Select is OFF, the current pattern generation unit 1021 sets the DC current command Idc = 0.

[0057] Referring again to Figure 3, the current pattern generation unit 1021 outputs the generated DC current command Idc to the current control unit 1022 and the constant calculation unit 1025.

[0058] The current control unit 1022 receives the current i detected by the current detector 12, the DC current command Idc output from the current pattern generation unit 1021, and the DC phase angle command θdc, and the measurement voltage command vm * Specifically, the current control unit 1022 generates a measurement voltage command vm such that the current value of the current i follows the DC current command Idc and the phase angle of the current i follows the DC phase angle command θdc. * The DC phase angle command θdc is a fixed value. The current control unit 1022 generates the measured voltage command vm. * This is output to the first selection unit 103.

[0059] The rotational coordinate transformation unit 1023 receives the secondary magnetic flux φ2 output from the secondary magnetic flux calculation unit 14 and the DC phase angle command θdc as input. The rotational coordinate transformation unit 1023 performs a rotational coordinate transformation on the secondary magnetic flux φ2 in the axial direction of the DC phase angle command θdc to generate the secondary magnetic flux φ2v in the current axis direction. The rotational coordinate transformation unit 1023 outputs the generated secondary magnetic flux φ2v in the current axis direction to the constant calculation unit 1025.

[0060] The constant calculation unit 1025 receives the selection signal Select, the DC current command Idc output from the current pattern generation unit 1021, the secondary magnetic flux φ2v in the current axis direction output from the rotation coordinate transformation unit 1023, the correction voltage setting value Ve, and the primary resistance setting value R1 as inputs. Based on the secondary magnetic flux φ2v in the current axis direction when the selection signal Select is ON1 and ON2, the constant calculation unit 1025 calculates the correction voltage measurement value Vem and the primary resistance measurement value R1m. The constant calculation unit 1025 outputs the calculated correction voltage measurement value Vem to the second selection unit 104 and the calculated primary resistance measurement value R1m to the third selection unit 105.

[0061] Next, we will explain in more detail the calculation of the corrected voltage measurement value Vem and the primary resistance measurement value R1m by the constant calculation unit 1025.

[0062] When the current i flowing through induction motor 1 is DC, the component φ2va in the direction of the current axis and the component φ2vb perpendicular to the current axis of the secondary magnetic flux φ2v in the direction of the current axis are expressed by the following equations (3) and (4).

[0063]

number

[0064] In equations (3) and (4), Swa is the component of the switching signal Sw in the direction of the current axis, and Swb is the component of the switching signal Sw orthogonal to the current axis.

[0065] If the correction voltage setting value Ve = VeReal + dVe and the primary resistance setting value R1 = R1Real + dR1, then equation (3) becomes equation (5) below. VeReal is the true value of the correction voltage, and dVe is the error value of the correction voltage. Also, R1Real is the true value of the primary resistance, and dR1 is the error value of the primary resistance.

[0066]

number

[0067] The first term on the right-hand side of equation (5) represents the true value of the secondary magnetic flux φ2. If the true value of the component of the secondary magnetic flux φ2 in the direction of the current axis is denoted as the true secondary magnetic flux φ2RealA, then equation (5) becomes equation (6).

[0068]

number

[0069] If the ON1 state of the selection signal Select continues for a time Tm1, the axial component φ2va of the secondary magnetic flux φ2v is expressed by the following equation (7). φ2va=φ2RealA-L2 / M*dVe*Tm1-L2 / M*dR1*I1*Tm1=φ2RealA-L2 / M*P1*Tm1...Formula (7)

[0070] Subsequently, if the ON2 state of the selection signal Select continues for a time Tm2, ​​the axial component φ2va of the secondary magnetic flux φ2v is expressed by the following equation (8). φ2va=φ2RealA-L2 / M*dVe*Tm1-L2 / M*dR1*I1*Tm1-L2 / M*dVe*Tm2-L2 / M*dR1*I2*Tm2 =φ2RealA-L2 / M*P1*Tm1-L2 / M*P2*Tm2...Formula (8)

[0071] In addition, in equations (7) and (8), P1 = dVe + dR1 * I1 ... Equation (9) P2 = dVe + dR1 * I2 ... Equation (10) That is what they say.

[0072] The following explains how to find P1 and P2. First, we will explain how to find P1.

[0073] Let (φ2va1H, φ2vb1H) be the relative values ​​of the secondary magnetic flux φ2v at time Tm1 / 2 with respect to time 0, and (φ2RealA1H, φ2RealB1H) be the relative values ​​of the true values ​​of the secondary magnetic flux φ2v at time Tm1 / 2 with respect to time 0. Also, let (φ2va1, φ2vb1) be the relative values ​​of the secondary magnetic flux φ2v at time Tm1 with respect to time 0, and (φ2RealA1, φ2RealB1) be the relative values ​​of the true values ​​of the secondary magnetic flux φ2v at time Tm1 with respect to time 0. In this case, φ2va1H, φ2vb1H, φ2va1, and φ2vb1 are expressed by equations (11), (12), (13), and (14), respectively. φ2va1H=φ2RealA1H-L2 / M*P1*Tm1 / 2...Formula (11) φ2vb1H=φ2RealB1H...Formula (12) φ2va1=φ2RealA1-L2 / M*P1*Tm1...Formula (13) φ2vb1=φ2RealB1...Formula (14)

[0074] Since the true value of the secondary magnetic flux φ2v of the current axis traces a circle with rotational speed ωmc, the trajectory length of the true value of the secondary magnetic flux φ2v of the current axis in the interval from time 0 to Tm1 / 2 is equal to the trajectory length of the true value of the secondary magnetic flux φ2v of the current axis in the interval from time Tm1 / 2 to Tm1. Therefore, the following equation (15) holds. φ2RealA1H 2 +φ2RealB1H 2 =(φ2RealA1-φ2RealA1H) 2 +(φ2RealB1-φ2RealB1H) 2 ...Equation (15)

[0075] Substituting equations (11) to (14) into equation (15) and solving for P1, we obtain the following equation (16). P1=M / L2*[φ2va1*(φ2va1-2*φ2va1H)+φ2vb1*(φ2vb1-2*φ2vb1H)] / (2*φ2va1H-φ2va1) / Tm1 ...Equation (16)

[0076] As shown in equation (16), P1 is expressed by (φ2va1H, φ2vb1H) and (φ2va1, φ2vb1) obtained from the secondary magnetic flux φ2v of the current axis, and Tm1, the time during which the ON1 state persists. Therefore, P1 can be calculated from equation (16).

[0077] Next, I will explain how to find P2.

[0078] Let (φ2va2H, φ2vb2H) be the relative values ​​of the current-axis secondary magnetic flux φ2v at time Tm1 + Tm2 / 2 with respect to time Tm1, and (φ2RealA2H, φ2RealB2H) be the relative values ​​of the true values ​​of the current-axis secondary magnetic flux φ2v at time Tm1 + Tm2 / 2 with respect to time Tm1. Also, let (φ2va2, φ2vb2) be the relative values ​​of the current-axis secondary magnetic flux φ2v at time Tm1 + Tm2 with respect to time Tm1, and (φ2RealA2, φ2RealB2) be the relative values ​​of the true values ​​of the current-axis secondary magnetic flux φ2v at time Tm1 + Tm2 with respect to time Tm1. In this case, φ2va2H, φ2vb2H, φ2va2, and φ2vb2 are expressed by equations (17), (18), (19), and (20), respectively. φ2va2H=φ2RealA2H-L2 / M*P2*Tm2 / 2...Formula (17) φ2vb2H=φ2RealB2H...Formula (18) φ2va2=φ2RealA2-L2 / M*P2*Tm2...Formula (19) φ2vb2=φ2RealB2...Formula (20)

[0079] Since the true value of the secondary magnetic flux φ2v of the current axis traces a circle with rotational speed ωmc, the trajectory length of the true value of the secondary magnetic flux φ2v of the current axis in the time interval Tm1 to Tm1+Tm2 / 2 is equal to the trajectory length of the true value of the secondary magnetic flux φ2v of the current axis in the time interval Tm1+Tm2 / 2 to Tm1+Tm2. Therefore, the following equation (21) holds. φ2RealA2H 2 +φ2RealB2H 2 =(φ2RealA2-φ2RealA2H) 2 +(φ2RealB2-φ2RealB2H) 2 ...Equation (21)

[0080] Substituting equations (17) to (20) into equation (21) and solving for P2, we obtain the following equation (22). P2=M / L2*[φ2va2*(φ2va2-2*φ2va2H)+φ2vb2*(φ2vb2-2*φ2vb2H)] / (2*φ2va2H-φ2va2) / Tm2 ...Equation (22)

[0081] As shown in equation (22), P2 is expressed as (φ2va2H, φ2vb2H) and (φ2va2, φ2vb2) obtained from the secondary magnetic flux φ2v of the current axis, and the time Tm2 during which the ON2 state persists. Therefore, P2 can be calculated from equation (22).

[0082] Once P1 and P2 are obtained, the corrected voltage error value dVe and the primary resistance error value dR1 can be calculated from equations (9) and (10). Once the corrected voltage error value dVe and the primary resistance error value dR1 are determined, since Vem = Ve - dVe and R1m = R1 - dR1, the constant calculation unit 1025 can calculate the corrected voltage measurement value Vem and the primary resistance measurement value R1m. In this way, the constant calculation unit 1025 calculates the corrected voltage measurement value Vem and the primary resistance measurement value R1m based on the current axis secondary magnetic flux φ2v in the ON1 state (first state) and the ON2 state (second state), respectively, of the selection signal Select.

[0083] Next, the configuration of the constant calculation unit 1025 will be described. Figure 5 shows an example of the configuration of the constant calculation unit 1025.

[0084] As shown in Figure 5, the constant calculation unit 1025 includes a first data selector 21, a second data selector 22, a first auxiliary calculation unit 23, a second auxiliary calculation unit 24, an error calculation unit 25, a first corrector 26, and a second corrector 27.

[0085] The first data selector 21 receives a selection signal Select, a time Tm1 (a first predetermined time), and the current axis secondary magnetic flux φ2v as input. Based on the selection signal Select, the time Tm1, and the current axis secondary magnetic flux φ2v, the first data selector 21 uses equations (11) to (12) described above to calculate the relative values ​​(φ2va1H, φ2vb1H) of the current axis secondary magnetic flux φ2v at time Tm1 / 2 with respect to time 0, and outputs them to the first auxiliary calculator 23 as the current axis secondary magnetic flux at the first time point. Furthermore, the first data selector 21 calculates the relative values ​​(φ2va1, φ2vb1) of the current axis secondary magnetic flux φ2v at time Tm1 with respect to time 0, using equations (13) to (14) described above, based on the selection signal Select, time Tm1, and current axis secondary magnetic flux φ2v, and outputs them to the first auxiliary calculator 23 as the current axis secondary magnetic flux at the second time point.

[0086] In other words, the first data selector 21 outputs the relative values ​​(φ2va1H, φ2vb1H) of the current axis secondary flux φ2v at half the time Tm1 (Tm1 / 2) as the current axis secondary flux at the first time point, using the current axis secondary flux φ2v at time 0 (the time when the selection signal Select transitions from the OFF state (third state) to the ON1 state (first state)) as a reference. Furthermore, the first data selector 21 outputs the relative values ​​(φ2va1H, φ2vb1H) of the current axis secondary flux φ2v at the time Tm1 has elapsed as the current axis secondary flux at the second time point, using the current axis secondary flux φ2v at time 0 (the time when the selection signal Select transitions from the OFF state (third state) to the ON1 state (first state)) as a reference.

[0087] The second data selector 22 receives the selection signal Select, time Tm2 (second predetermined time), and the current axis secondary magnetic flux φ2v as input. Based on the selection signal Select, time Tm2, ​​and current axis secondary magnetic flux φ2v, the second data selector 22 uses equations (17) to (18) described above to calculate the relative value (φ2va2H, φ2vb2H) of the current axis secondary magnetic flux φ2v at time Tm1 + Tm2 / 2 with respect to time Tm1, and outputs it to the second auxiliary calculator 24 as the current axis secondary magnetic flux at the third time point. Furthermore, the second data selector 22 calculates the relative values ​​(φ2va2, φ2vb2) of the current axis secondary magnetic flux φ2v at time Tm1 + Tm2 with respect to time Tm1, using equations (19) to (20) described above, based on the selection signal Select, time Tm2, ​​and current axis secondary magnetic flux φ2v, and outputs them to the second auxiliary calculator 24 as the current axis secondary magnetic flux at the fourth time point.

[0088] In other words, the second data selector 22 outputs the relative values ​​(φ2va2H, φ2vb2H) of the current axis secondary flux φ2v at half the time Tm2 (Tm1 + Tm2 / 2) as the current axis secondary flux at the third time point, using the current axis secondary flux φ2v at the time when the selection signal Select transitions from the ON1 state (first state) to the ON2 state (second state) as a reference. Furthermore, the second data selector 22 outputs the relative values ​​(φ2va2, φ2vb2) of the current axis secondary flux φ2v at the time Tm2 has elapsed (Tm1 + Tm2) as the current axis secondary flux at the fourth time point, using the current axis secondary flux φ2v at the time when the selection signal Select transitions from the ON1 state (first state) to the ON2 state (second state) as a reference.

[0089] The first auxiliary calculator 23 receives the secondary magnetic flux of the current axis at the first time point (φ2va1H, φ2vb1H), the secondary magnetic flux of the current axis at the second time point (φ2va1, φ2vb1), and time Tm1 as inputs. Based on the secondary magnetic flux of the current axis at the first time point (φ2va1H, φ2vb1H), the secondary magnetic flux of the current axis at the second time point (φ2va1, φ2vb1), and time Tm1, the first auxiliary calculator 23 calculates P1 (first error value), which is the error value at time Tm1 caused by the correction voltage and primary resistance, using the above-described equation (16). The first auxiliary calculator 23 outputs the calculated P1 to the error calculator 25.

[0090] The second auxiliary calculator 24 receives the current axis secondary flux (φ2va2H, φ2vb2H) at the third time point, the current axis secondary flux (φ2va2, φ2vb2) at the fourth time point, and time Tm2 as input. Based on the current axis secondary flux (φ2va2H, φ2vb2H) at the third time point, the current axis secondary flux (φ2va2, φ2vb2) at the fourth time point, and time Tm2, ​​the second auxiliary calculator 24 calculates P2 (second error value), which is the error value at time Tm2 caused by the correction voltage and primary resistance, using the above-described equation (22). The second auxiliary calculator 24 outputs the calculated P2 to the error calculator 25.

[0091] The error calculator 25 receives P1 (first error value), P2 (second error value), and the DC current command Idc as inputs. Based on P1, P2, and the currents I1 and I2 (first DC current and second DC current) indicated by the DC current command Idc, the error calculator 25 calculates the corrected voltage error value dVe and the primary resistance error value dR1 using the above-described equations (9) and (10). The error calculator 25 outputs the calculated corrected voltage error value dVe to the first corrector 26 and the calculated primary resistance error value dR1 to the second corrector 27.

[0092] The first corrector 26 receives a correction voltage set value Ve and a correction voltage error value dVe as inputs. Based on the correction voltage set value Ve and the correction voltage error value dVe, the first corrector 26 calculates the correction voltage measurement value Vem. Specifically, the first corrector 26 calculates the correction voltage measurement value Vem using the formula Vem = Ve - dVe. The first corrector 26 outputs the calculated correction voltage measurement value Vem to the second selection unit 104.

[0093] The second corrector 27 receives the primary resistance setting value R1 and the primary resistance error value dR1 as inputs. The second corrector 27 calculates the primary resistance measurement value R1m based on the primary resistance setting value R1 and the primary resistance error value dR1. Specifically, the second corrector 27 calculates the primary resistance measurement value R1m using the formula R1m = R1 - dR1. The second corrector 27 outputs the calculated primary resistance measurement value R1m to the third selection unit 105.

[0094] Thus, in this embodiment, the control device 100 consists of a PWM inverter 11 and a voltage command vv *A PWM signal generator 17 outputs a switching signal Sw to the PWM inverter 11 based on the above; a current detector 12 detects the current i flowing through the induction motor 1; a voltage correction unit 13 calculates an estimated voltage vin based on the switching signal Sw, the output voltage Vdc of the DC voltage source 2, the current i, and the correction voltage VeC; a secondary magnetic flux calculation unit 14 calculates the secondary magnetic flux φ2 of the induction motor 1 based on the primary resistance R1C of the induction motor 1, the estimated voltage vin, and the current i; a speed calculation unit 15 calculates the rotational speed ωmc of the induction motor 1 based on the secondary magnetic flux φ2 and the current i; and a control voltage command vc such that a torque corresponding to the torque command TqRef is output from the induction motor 1 based on the current i and the rotational speed ωmc of the induction motor 1. * The system includes an induction motor control unit 16 that generates a signal, a selection signal generation unit 101 that generates a selection signal Select having an ON1 state, an ON2 state, and an OFF state, and a control constant setting unit 106 that determines a corrected voltage measurement value Vem and a primary resistance measurement value R1m.

[0095] The control constant setting unit 106 sets a measurement voltage command vm such that when the selection signal Select is ON1, a DC current of current value I1 flows to the induction motor 1, and when the selection signal Select is ON2, a DC current of current value I2 flows to the induction motor 1. * Voltage command vv * The PWM signal is output to the PWM signal generation unit 17. The control constant setting unit 106 determines the corrected voltage measurement value Vem and the primary resistance measurement value R1m based on the secondary magnetic flux φ2 of the induction motor 1 for both the ON1 state and the ON2 state.

[0096] By determining the corrected voltage measurement value Vem and the primary resistance measurement value R1m, the estimated voltage vin, secondary magnetic flux φ2, and rotational speed ωmc can be calculated with high accuracy without being affected by individual differences in the switching elements constituting the PWM inverter 11 or the temperature of the induction motor 1. As a result, the accuracy of torque control of the induction motor 1 can be improved. Furthermore, in the control device 100 according to this disclosure, the rotational speed ωmc of the induction motor 1 is not used in the calculation of the corrected voltage measurement value Vem and the primary resistance measurement value R1m, so the corrected voltage measurement value Vem and the primary resistance measurement value R1m can be calculated even before the induction motor 1 is started.

[0097] Although the embodiments described above are representative examples, it will be apparent to those skilled in the art that many modifications and substitutions are possible within the spirit and scope of the present invention. Therefore, the present invention should not be interpreted as being limited by the embodiments described above, and various modifications and changes are possible without departing from the scope of the claims. [Explanation of Symbols]

[0098] 1 induction machine 2 DC voltage source 11 PWM Inverter 12 Current detector 13 Voltage Correction Section 14. Secondary magnetic flux calculation unit 15 Speed ​​calculation section 16. Induction machine control unit 17 PWM signal generation unit 21 First Data Selector 22. Second Data Selector 23 1st auxiliary computing unit 24 2nd auxiliary computing unit 25 Error calculator 26 1st corrector 27 Second corrector 100 Control device 101 Selection signal generation unit 102 Control constant measurement unit 103 First Selection Section 104 Second Selection Section 105 Third Selection Section 106 Control constant setting unit 1021 Current pattern generation section 1022 Current Control Unit 1023 Rotational Coordinate Transformation Unit 1025 Constant Calculation Unit

Claims

1. A control device for a guidance system, A PWM inverter equipped with a switching element supplies an AC voltage to the induction motor by pulse width modulation of the output voltage of a DC voltage source, A PWM signal generation unit outputs a switching signal to the PWM inverter that controls the switching element based on a voltage command, A current detector for detecting the current flowing through the induction motor, A voltage correction unit calculates an estimated voltage by estimating the output voltage of the PWM inverter based on the switching signal, the output voltage of the DC voltage source, the current detected by the current detector, and a correction voltage for correcting the voltage corresponding to the output of the PWM inverter. A secondary magnetic flux calculation unit calculates the secondary magnetic flux of the induction motor based on the primary resistance of the induction motor, the estimated voltage, and the current detected by the current detector. A speed calculation unit calculates the rotational speed of the induction machine based on the secondary magnetic flux and the current detected by the current detector, An induction motor control unit generates a control voltage command that instructs the output voltage of the PWM inverter such that a torque corresponding to the torque command is output from the induction motor, based on the current detected by the current detector and the rotational speed. A selection signal generation unit that generates a selection signal having a first state, a second state, and a third state, The system includes a control constant setting unit that determines the correction voltage measurement value, which is the measurement value of the correction voltage, and the primary resistance measurement value, which is the measurement value of the primary resistance. The control constant setting unit is, In the first state, a current pattern generating unit generates a DC current command indicating a first DC current, and in the second state, a current pattern generating unit generates a DC current command indicating a second DC current. A current control unit that generates a measuring voltage command that instructs the output voltage of the PWM inverter such that the current value of the current flowing through the induction motor follows the DC current command and the phase angle of the current flowing through the induction motor follows the DC phase angle command, A rotational coordinate transformation unit that performs rotational coordinate transformation in the axial direction of the DC phase angle command on the secondary magnetic flux and outputs the current axis secondary magnetic flux, The system includes a constant calculation unit that calculates the corrected voltage measurement value and the primary resistance measurement value based on the current axis secondary magnetic flux output from the rotational coordinate transformation unit in the first state and the second state, respectively. The selection signal generation unit, in response to the input of a predetermined command, transitions the selection signal from the third state to the first state, transitions it from the first state to the second state after a first predetermined time has elapsed, and transitions it from the second state to the third state after a second predetermined time has elapsed. The constant calculation unit is, A first data selector outputs a second current axis magnetic flux at a first time point and a second current axis magnetic flux at a second time point, based on the selection signal, the first predetermined time, and the second current axis magnetic flux. A second data selector outputs a third time point current axis secondary flux and a fourth time point current axis secondary flux based on the selection signal, the second predetermined time, and the current axis secondary flux. A first auxiliary calculator that calculates a first error value, which is an error value caused by the correction voltage and the primary resistance at the first predetermined time, based on the first time point current axis secondary magnetic flux, the second time point current axis secondary magnetic flux, and the first predetermined time, A second auxiliary calculator that calculates a second error value, which is an error value caused by the correction voltage and the primary resistance at the second predetermined time, based on the third time point current axis secondary magnetic flux, the fourth time point current axis secondary magnetic flux, and the second predetermined time, An error calculator that calculates a corrected voltage error value and a primary resistance error value based on the first error value, the second error value, the first DC current, and the second DC current, A first corrector calculates the corrected voltage measurement value based on a corrected voltage setting value which is a preset setting value of the corrected voltage and the corrected voltage error value, A control device comprising: a second corrector that calculates the primary resistance measurement value based on a primary resistance setting value which is a preset setting value of the primary resistance and the primary resistance error value.

2. In the control device according to claim 1, The first data selector is, With reference to the current axis secondary magnetic flux at the time the selection signal transitions from the third state to the first state, The relative value of the secondary magnetic flux of the current axis at half the time of the first predetermined time is output as the secondary magnetic flux of the current axis at the first time point. A control device that outputs the relative value of the current axis secondary magnetic flux at the time when the first predetermined time has elapsed as the current axis secondary magnetic flux at the second time.

3. In the control device according to claim 1, The second data selector is, With reference to the current axis secondary magnetic flux at the time the selection signal transitions from the first state to the second state, The relative value of the current axis secondary magnetic flux at half the second predetermined time is output as the current axis secondary magnetic flux at the third time point. A control device that outputs the relative value of the current axis secondary magnetic flux at the time when the second predetermined time has elapsed as the current axis secondary magnetic flux at the fourth time.

4. In the control device according to claim 1, The control constant setting unit is a control device that, in the third state, sets the correction voltage measurement value as the correction voltage.

5. In the control device according to claim 1, The control constant setting unit is a control device that, in the third state, sets the primary resistance measurement value as the primary resistance.

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