JP4805679B2 - Inverter control device - Google Patents

Description

  The present invention relates to an inverter control device for driving an AC motor, and in particular, has a motor constant correction calculating means for automatically correcting an error between a motor constant design value of the inverter control device and a motor constant of the AC motor. The present invention relates to an inverter control device capable of setting an initial value of motor constant correction calculation means at the time of startup.

  As an AC motor control method, vector control capable of realizing high response and high accuracy of torque control is widely used in the railway field and the like. In vector control, current and magnetic flux are independently defined based on an orthogonal coordinate system that rotates in synchronization with the rotating magnetic flux generated inside the AC motor, and the AC motor is controlled using motor constant design values and speed information of the AC motor. .

  By the way, the resistance value which is one of the motor constants varies with the heat generation of the AC motor and the ambient temperature. For this reason, an error between the motor constant design value used in vector control and the motor constant of the AC motor (hereinafter referred to as a motor constant error) occurs due to the temperature change of the AC motor, and the control performance is degraded. On the other hand, an inverter control device having motor constant correction calculation means for automatically correcting a motor constant error is described in Patent Document 1, for example.

In the inverter control device described in Patent Document 1, an operation amount of current control with respect to a current component in the magnetic flux direction of the orthogonal coordinate system (hereinafter referred to as excitation current) and a current component orthogonal to the excitation current (hereinafter referred to as torque current). The motor constant error is corrected using the operation amount of the current control for the above. Further, in the inverter control device described in Patent Document 1, motor constant correction is started every time the inverter is started with a state where there is no motor constant error as an initial value.
JP 2001-169599 A

  As described above, since the resistance value, which is one of the motor constants, varies with the heat generated by the AC motor and the ambient temperature, the motor constant error when the inverter is restarted varies depending on the conditions during the inverter stop. Therefore, as in Patent Document 1, when starting motor constant correction with an initial value in a state where there is no motor constant error every time the inverter is started, depending on the temperature state of the AC motor, control is performed from a state where the motor constant error is large. Will start. As a result, there is a problem that the control performance at the time of starting the inverter is lowered. Patent Document 1 does not describe the recognition of the above problems and the means for solving the problems.

  An object of the present invention is to suppress a motor constant error at the time of starting an inverter and improve control performance at the time of starting the inverter in an inverter control device having a motor constant correction calculating means for correcting a motor constant error.

  In order to solve the above problems, an inverter control device according to the present invention includes a motor constant correction calculation unit that corrects a motor constant error of an AC motor, and a motor constant correction that sets an initial value of the motor constant correction calculation unit when the inverter is started. Initial value setting means, and the motor constant correction initial value setting means interpolates a motor constant correction value that is an output of the motor constant correction calculation means while the inverter is stopped, and when the inverter is restarted. It is set as an initial value of the motor constant correction value.

  According to the present invention, the motor constant correction value when the inverter is restarted is interpolated, and the interpolated motor constant correction value is set as the initial value of the motor constant correction value when the inverter is restarted. Errors can be suppressed, and control performance such as torque accuracy and current accuracy can be improved. Particularly in a railway vehicle, torque accuracy at the time of starting the inverter is important for improving the ride comfort, and the effect of the present invention is effective for the railway vehicle.

  Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an inverter control apparatus according to a first embodiment of the present invention. The PWM inverter 1 converts the DC voltage E _cf obtained from the DC power source 2 through the power receiving filter 3 into a three-phase AC voltage. The three-phase AC voltage generated by the PWM inverter 1 is applied to the induction motor 4 to drive the induction motor 4. Although FIG. 1 illustrates one induction motor, a plurality of induction motors may be used. The alternating currents I _u , I _v , I _w flowing into the induction motor 4 are detected by the current detection means 5, and the coordinate conversion means 6 converts the alternating currents I _u , I _v , I _w into direct currents I _d , I _q . Is done. The current commands I _dp and I _qp which are target values for the direct currents I _d and I _q are generated by the current command generator 7. The speed information F _r of the induction motor 4 is detected by the speed detection means 8. The vector control arithmetic means 9 is used for driving the induction motor 4 using the current commands I _dp and I _qp , the DC current I _d and I _q , the speed information F _r and the DC voltage E _cf obtained from the power receiving filter 3. It calculates a modulation factor V _c and a voltage phase theta. PWM control operation unit 10 generates a gate signal which is a switching instruction to the PWM inverter (Gate Signal) by a pulse width modulation scheme from the modulation factor V _c and a voltage phase generated by the vector control calculating unit 9 theta.

  The motor constant correction calculation means 12 calculates motor constant correction values ΔR and ΔM which are variables for correcting an error between the motor constant design value of the vector control calculation means 9 and the motor constant of the induction motor 4 while the inverter is activated. The control performance is improved by calculating (the solid line portion in 14 of FIG. 1) and correcting the motor constant correction design value of the vector control calculation means 9. The motor constant correction values ΔR and ΔM are calculated using the amount of voltage operation in the vector control calculation means 9 but are not shown here. Details of the motor constant correction calculation means 12 are omitted because there are known examples such as the above-mentioned Patent Document 1.

The motor constant correction initial value setting means 11 sets initial values ΔR ₀ and ΔM ₀ at the time of starting the inverter with respect to the motor constant correction values ΔR and ΔM (ΔR ₀ and ΔM ₀ at time (B) in item 14 of FIG. 1). . ΔR ₀ and ΔM ₀ are motor stop correction values ΔR and ΔM (ΔR and ΔM at time (A) in item 14 of FIG. 1) as initial values immediately before the inverter stop, and the inverter stop obtained from the speed information F _r and the timer 13. Is calculated by performing interpolation while the inverter is stopped, using the elapsed time T from.
A railway vehicle is taken as an example of the inverter control device, and the motor constant correction initial value setting means 11 will be described. Railway vehicles are generally driven by a squirrel-cage induction motor. In the case of a squirrel-cage induction motor, the rotor is generally made of copper. The resistance value R at the temperature t of copper is expressed by the formula (1).
R = R _t0 · (1 + α _t0 · (t−t ₀ )) (1)
here,
R _t0 : resistance value (Ω) at temperature t ₀ (° C.)
α _t0 : Temperature coefficient at temperature t ₀ (° C.) (1 / ° C.)

In the case of t ₀ = 20 ° C., α = 3.96 × 10 ⁻³ (1 / ° C.). In a railway vehicle, since the temperature of the induction motor rises by about 100 ° C. during traveling, the secondary resistance varies by about 30% from Equation (1). Further, since the change in the secondary resistance value and the temperature change of the induction motor are proportional to each other from the equation (1), the change in the resistance value can be calculated from the temperature change of the induction motor.

  When the induction motor is cooled by running wind, the motor constant correction value while the inverter is stopped includes the change in the motor constant when the temperature of the induction motor is the smallest (one-dot chain line (A) in FIG. 3) and the temperature of the induction motor. The range is surrounded by the change in the motor constant correction value at the maximum speed at which the change is greatest (the dashed line (B) in FIG. 3). From the alternate long and short dashed lines (A) and (B) in FIG. 3, the range in which the motor constant correction value changes while the inverter is stopped (alternate dashed lines (A) and (B) in FIG. 4) can be obtained.

Therefore, based on the elapsed time from the velocity information F _r and the inverter stopping the drive before stopping, to fit the range surrounded by a chain line shown in FIG. 4 (A) (B), and interpolates the motor constant correction value (Dotted line in FIG. 4). By setting the interpolated motor constant as the initial value of the motor constant correction value when starting the inverter, the motor constant error when starting the inverter can be suppressed, and control performance such as torque accuracy and current accuracy can be improved. In the case of forced cooling with a blower or the like, the alternate long and short dash lines (A) and (B) of FIGS. Further, the speed information F _r for interpolating the motor constant correction value is always read while the inverter is stopped, and the speed information at that time may be used.

When the inverter stop period is short, the motor constant correction initial value setting means 9 holds the motor constant correction values ΔR and ΔM immediately before the inverter stop while the inverter is stopped as shown in FIG. A method of setting the motor constant correction values as the initial values ΔR ₀ and ΔM ₀ when the inverter is restarted may be used. Further, as a motor constant correction value to be interpolated while the inverter is stopped, a method of interpolating only a motor constant correction value for a resistance value having a large variation with respect to a temperature change may be used.

FIG. 6 shows an inverter control apparatus according to the second embodiment of the present invention. The PWM inverter 1 converts the DC voltage E _cf obtained from the DC power source 2 through the power receiving filter 3 into a three-phase AC voltage. The three-phase AC voltage generated by the PWM inverter 1 is applied to the induction motor 4 to drive the induction motor 4. Although FIG. 6 illustrates one induction motor, a plurality of induction motors may be used. The alternating currents I _u , I _v , I _w flowing into the induction motor 4 are detected by the current detection means 5, and the coordinate conversion means 6 converts the alternating currents I _u , I _v , I _w into direct currents I _d , I _q . Is done. The current commands I _dp and I _qp which are target values for the direct currents I _d and I _q are generated by the current command generator 7. The speed information F _r of the induction motor 4 is detected by the speed detection means 8. The vector control arithmetic means 9 is used for driving the induction motor 4 using the current commands I _dp and I _qp , the DC current I _d and I _q , the speed information F _r and the DC voltage E _cf obtained from the power receiving filter 3. It calculates a modulation factor V _c and a voltage phase theta. PWM control operation unit 10 generates a gate signal which is a switching instruction to the PWM inverter (Gate Signal) by a pulse width modulation scheme from the modulation factor V _c and a voltage phase generated by the vector control calculating unit 9 theta.

  The motor constant correction calculation means 12 calculates motor constant correction values ΔR and ΔM which are variables for correcting an error between the motor constant design value of the vector control calculation means 9 and the motor constant of the induction motor 4 while the inverter is activated. The control performance is improved by calculating and correcting the motor constant correction design value of the vector control calculation means 9. The motor constant correction values ΔR and ΔM are calculated using the amount of voltage operation in the vector control calculation means 9 but are not shown here. Details of the motor constant correction calculation means 12 are omitted because there are known examples such as the above-mentioned Patent Document 1.

The motor constant correction initial value setting means 11 sets initial values ΔR ₀ and ΔM ₀ at the time of starting the inverter with respect to the motor constant correction values ΔR and ΔM. ΔR ₀ and ΔM ₀ are the inverters being stopped from the relationship of the equation (1) using the motor constant correction values ΔR and ΔM immediately before stopping the inverter as initial values and using the temperature information t of the induction motor obtained from the temperature detecting means 15. It is calculated by interpolating the motor constant correction value. Note that, as a motor constant correction value to be interpolated while the inverter is stopped, a method of interpolating only a motor constant correction value for a resistance value having a large variation with respect to a temperature change may be used.

FIG. 7 shows an inverter control apparatus according to a third embodiment of the present invention. The PWM inverter 1 converts the DC voltage E _cf obtained from the DC power source 2 through the power receiving filter 3 into a three-phase AC voltage. The three-phase AC voltage generated by the PWM inverter 1 is applied to the induction motor 4 to drive the induction motor 4. Although FIG. 7 illustrates one induction motor, a plurality of induction motors may be used. The alternating currents I _u , I _v , I _w flowing into the induction motor 4 are detected by the current detection means 5, and the coordinate conversion means 6 converts the alternating currents I _u , I _v , I _w into direct currents I _d , I _q . Is done. The current commands I _dp and I _qp which are target values for the direct currents I _d and I _q are generated by the current command generator 7. The speed information F _r of the induction motor 4 is detected by the speed detection means 8. The vector control arithmetic means 9 is used for driving the induction motor 4 using the current commands I _dp and I _qp , the DC current I _d and I _q , the speed information F _r and the DC voltage E _cf obtained from the power receiving filter 3. It calculates a modulation factor V _c and a voltage phase theta. PWM control operation unit 10 generates a gate signal which is a switching instruction to the PWM inverter (Gate Signal) by a pulse width modulation scheme from the modulation factor V _c and a voltage phase generated by the vector control calculating unit 9 theta.

  The motor constant correction calculation means 12 calculates motor constant correction values ΔR and ΔM which are variables for correcting an error between the motor constant design value of the vector control calculation means 9 and the motor constant of the induction motor 4 while the inverter is activated. The control performance is improved by calculating and correcting the motor constant correction design value of the vector control calculation means 9. The motor constant correction values ΔR and ΔM are calculated using the amount of voltage operation in the vector control calculation means 9 but are not shown here. Details of the motor constant correction calculation means 12 are omitted because there are known examples such as the above-mentioned Patent Document 1.

The motor constant correction initial value setting means 11 sets initial values ΔR ₀ and ΔM ₀ at the time of starting the inverter with respect to the motor constant correction values ΔR and ΔM. ΔR ₀ , ΔM ₀ are motor constant correction values ΔR, ΔM immediately before the inverter stop, and initial values obtained from the inverter stop time T obtained from the speed information F _r and the timer 13 and the induction obtained from the temperature detection means 15. Using the temperature information t of the electric motor, calculation is performed by interpolating while the inverter is stopped from the relationship shown in FIGS. Note that, as a motor constant correction value to be interpolated while the inverter is stopped, a method of interpolating only a motor constant correction value for a resistance value that varies greatly with respect to a temperature change may be used.

FIG. 8 shows an inverter control apparatus according to a fourth embodiment of the present invention. The PWM inverter 1 converts the DC voltage E _cf obtained from the DC power source 2 through the power receiving filter 3 into a three-phase AC voltage. The three-phase AC voltage generated by the PWM inverter 1 is applied to the induction motor 4 to drive the induction motor 4. Although FIG. 8 illustrates one induction motor, a plurality of induction motors may be used. The alternating currents I _u , I _v , I _w flowing into the induction motor 4 are detected by the current detection means 5, and the coordinate conversion means 6 converts the alternating currents I _u , I _v , I _w into direct currents I _d , I _q . Is done. The current commands I _dp and I _qp which are target values for the direct currents I _d and I _q are generated by the current command generator 7. The speed information F _r of the induction motor 4 is converted by the voltage operation amount inside the speed sensorless vector control calculation means 16, the current commands I _dp and I _qp generated by the current command generation means 7, and the coordinate conversion means 6. It is generated by speed sensorless vector control that estimates speed information F ^ _r of the induction motor 4 from the DC currents I _d and I _q . The speed sensorless vector control calculation means 16 drives the induction motor 4 using the current commands I _dp , I _qp , the DC current I _d , I _q , the speed information F _r and the DC voltage E _cf obtained from the power receiving filter 3. The modulation factor V _c and the voltage phase θ are calculated. PWM control operation unit 10 generates a gate signal which is a switching instruction to the PWM inverter (Gate Signal) by a pulse width modulation scheme from the modulation factor V _c and a voltage phase generated by the vector control calculating unit 9 theta.

  The motor constant correction calculation means 12 calculates motor constant correction values ΔR and ΔM which are variables for correcting an error between the motor constant design value of the vector control calculation means 9 and the motor constant of the induction motor 4 while the inverter is activated. The control performance is improved by calculating (the solid line portion in 14 of FIG. 1) and correcting the motor constant correction design value of the vector control calculation means 9. The motor constant correction values ΔR and ΔM are calculated using the amount of voltage operation in the vector control calculation means 9 but are not shown here. Details of the motor constant correction calculation means 12 are omitted because there are known examples such as the above-mentioned Patent Document 1.

The motor constant correction initial value setting means 11 sets initial values ΔR ₀ and ΔM ₀ at the time of starting the inverter with respect to the motor constant correction values ΔR and ΔM. ΔR ₀ and ΔM ₀ have the relationship shown in FIGS. 2 to 4 using the motor constant correction values ΔR and ΔM immediately before the inverter stops and the speed information F ^ r and the elapsed time T obtained from the inverter 13 obtained from the timer 13. From this, it is calculated by interpolation while the inverter is stopped.

When the inverter stop period is short, the motor constant correction initial value setting means 9 holds the motor constant correction values ΔR and ΔM immediately before the inverter stop while the inverter is stopped as shown in FIG. A method of setting the motor constant correction values as the initial values ΔR ₀ and ΔM ₀ when the inverter is restarted may be used. Further, as a motor constant correction value to be interpolated while the inverter is stopped, a method of interpolating only a motor constant correction value for a resistance value having a large variation with respect to a temperature change may be used.

FIG. 9 shows an inverter control apparatus according to a fifth embodiment of the present invention. The PWM inverter 1 converts the DC voltage E _cf obtained from the DC power source 2 through the power receiving filter 3 into a three-phase AC voltage. The three-phase AC voltage generated by the PWM inverter 1 is applied to the induction motor 4 to drive the induction motor 4. Although FIG. 9 illustrates one induction motor, a plurality of induction motors may be used. The alternating currents I _u , I _v , I _w flowing into the induction motor 4 are detected by the current detection means 5, and the coordinate conversion means 6 converts the alternating currents I _u , I _v , I _w into direct currents I _d , I _q . Is done. The current commands I _dp and I _qp which are target values for the direct currents I _d and I _q are generated by the current command generator 7. The speed information F _r of the induction motor 4 is converted by the voltage operation amount inside the speed sensorless vector control calculation means 16, the current commands I _dp and I _qp generated by the current command generation means 7, and the coordinate conversion means 6. It is generated by speed sensorless vector control that estimates speed information F ^ _r of the induction motor 4 from the DC currents I _d and I _q . The speed sensorless vector control calculation means 16 drives the induction motor 4 using the current commands I _dp , I _qp , the DC current I _d , I _q , the speed information F _r and the DC voltage E _cf obtained from the power receiving filter 3. The modulation factor V _c and the voltage phase θ are calculated. PWM control operation unit 10 generates a gate signal which is a switching instruction to the PWM inverter (Gate Signal) by a pulse width modulation scheme from the modulation factor V _c and a voltage phase generated by the vector control calculating unit 9 theta.

  The motor constant correction calculation means 12 calculates motor constant correction values ΔR and ΔM which are variables for correcting an error between the motor constant design value of the vector control calculation means 9 and the motor constant of the induction motor 4 while the inverter is activated. The control performance is improved by calculating (the solid line portion in 14 of FIG. 1) and correcting the motor constant correction design value of the vector control calculation means 9. The motor constant correction values ΔR and ΔM are calculated using the amount of voltage operation in the vector control calculation means 9 but are not shown here. Details of the motor constant correction calculation means 12 are omitted because there are known examples such as the above-mentioned Patent Document 1.

The motor constant correction initial value setting means 11 sets initial values ΔR ₀ and ΔM ₀ at the time of starting the inverter with respect to the motor constant correction values ΔR and ΔM. ΔR ₀ and ΔM ₀ are the inverters being stopped from the relationship of the equation (1) using the motor constant correction values ΔR and ΔM immediately before stopping the inverter as initial values and using the temperature information t of the induction motor obtained from the temperature detecting means 15. It is calculated by interpolating the motor constant correction value. Note that, as a motor constant correction value to be interpolated while the inverter is stopped, a method of interpolating only a motor constant correction value for a resistance value having a large variation with respect to a temperature change may be used.

FIG. 10 shows an inverter control apparatus according to a sixth embodiment of the present invention. The PWM inverter 1 converts a DC voltage obtained from the DC power source 2 through the power receiving filter 3 into a three-phase AC voltage. The three-phase AC voltage generated by the PWM inverter 1 is applied to the induction motor 4 to drive the induction motor 4. Although FIG. 10 illustrates one induction motor, a plurality of induction motors may be used. The alternating currents I _u , I _v , I _w flowing into the induction motor 4 are detected by the current detection means 5, and the coordinate conversion means 6 converts the alternating currents I _u , I _v , I _w into direct currents I _d , I _q . Is done. The current commands I _dp and I _qp which are target values for the direct currents I _d and I _q are generated by the current command generator 7. The speed information F _r of the induction motor 4 is converted by the voltage operation amount inside the speed sensorless vector control calculation means 16, the current commands I _dp and I _qp generated by the current command generation means 7, and the coordinate conversion means 6. It is generated by speed sensorless vector control that estimates speed information F ^ _r of the induction motor 4 from the DC currents I _d and I _q . The speed sensorless vector control calculation means 16 drives the induction motor 4 using the current commands I _dp , I _qp , DC current I _d , I _q , speed information F ^ _r and the DC voltage obtained from the power receiving filter 3. It calculates a modulation factor V _c and a voltage phase theta. PWM control operation unit 10 generates a gate signal which is a switching instruction to the PWM inverter (Gate Signal) by a pulse width modulation scheme from the modulation factor V _c and a voltage phase generated by the vector control calculating unit 9 theta.

  The motor constant correction calculation means 12 calculates motor constant correction values ΔR and ΔM which are variables for correcting an error between the motor constant design value of the vector control calculation means 9 and the motor constant of the induction motor 4 while the inverter is activated. The control performance is improved by calculating (the solid line portion in 14 of FIG. 1) and correcting the motor constant correction design value of the vector control calculation means 9. The motor constant correction values ΔR and ΔM are calculated using the amount of voltage operation in the vector control calculation means 9 but are not shown here. Details of the motor constant correction calculation means 12 are omitted because there are known examples such as the above-mentioned Patent Document 1.

The motor constant correction initial value setting means 11 sets initial values ΔR ₀ and ΔM ₀ at the time of starting the inverter with respect to the motor constant correction values ΔR and ΔM. ΔR ₀ , ΔM ₀ were obtained from the temperature detection means 15 and the elapsed time T from the inverter stop obtained from the speed information F ^ r and the timer 13 with the motor constant correction values ΔR, ΔM immediately before the inverter stopped as the initial values. Using the temperature information t of the induction motor, calculation is performed by interpolation while the inverter is stopped from the relationship shown in FIGS.

  Note that, as a motor constant correction value to be interpolated while the inverter is stopped, a method of interpolating only a motor constant correction value for a resistance value having a large variation with respect to a temperature change may be used. As an example of the present invention, when the inverter stop period is short, a simulation was performed on a method of holding the motor constant correction value when the inverter was stopped. The simulation conditions were resistance error + 30%, constant speed, gate start at 1 second, gate stop at 9 seconds, and re-gate start at 11 seconds.

  11 and 12 show the simulation results. FIG. 11 shows a case where motor constant correction is started with an initial value in a state where there is no motor constant error every time the inverter is started, as in the prior art. FIG. 12 shows an example of the present invention in which the motor constant correction value when the inverter is stopped is held and the initial value of the motor constant correction value when the inverter is restarted when the inverter stop period is short. 11 and 12, (a) is a motor constant correction value for resistance error, and 1.0 indicates a state where there is no resistance error. (B) shows the deviation of the actual torque with respect to the torque command.

  In FIG. 11, since motor constant correction is started from a state where there is no motor constant error every time the inverter is started, a torque deviation of about 8% occurs every time the inverter is started. On the other hand, in FIG. 12, the motor deviation correction value when the inverter is stopped is held and used as the initial value when the inverter is restarted, so that the torque deviation at the time of inverter restart can be suppressed to about 4%.

  Thus, according to the present invention, it is possible to suppress the motor constant error when the inverter is restarted and to improve the control performance such as torque accuracy and current accuracy.

  In railway vehicles, inverter stops and restarts frequently, such as when the station stops or coasts. Therefore, instead of recalculating the motor constant correction value every time the inverter is started, while the inverter is stopped, the motor constant correction value is interpolated by the speed information while the inverter is stopped and the elapsed time from the inverter stop. By setting the initial value of the motor constant correction value when the inverter is restarted, control performance such as torque accuracy and current accuracy can be improved.

  In particular, in a railway vehicle, the torque accuracy at the time of starting the inverter affects the riding comfort, so that the improvement in torque accuracy, which is the effect of the present invention, is practically effective.

It is a figure which shows the inverter control apparatus of 1st Example of this invention. It is a figure which shows the relationship between motor temperature and resistance value. It is a figure which shows the motor temperature change during an inverter stop. It is a figure which shows the interpolation of the motor constant correction value of 1st Example of this invention. It is a figure which shows holding | maintenance of the motor constant correction value of 1st Example of this invention. It is a figure which shows the inverter control apparatus of 2nd Example of this invention. It is a figure which shows the inverter control apparatus of 3rd Example of this invention. It is a figure which shows the inverter control apparatus of 4th Example of this invention. It is a figure which shows the inverter control apparatus of 5th Example of this invention. It is a figure which shows the inverter control apparatus of 6th Example of this invention. It is a figure which shows the simulation result by a prior art. It is a figure which shows the simulation result by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 PWM inverter 2 DC power supply 3 Power receiving filter 4 Induction motor 5 Current detection means 6 Coordinate conversion means 7 Current command generation means 8 Speed detection means 9 Vector control calculation means 10 PWM control calculation means 11 Motor constant correction initial value setting means 12 Motor constant Correction calculation means 13 Timer 14 Change in motor constant correction value 15 Temperature detection means 16 Speed sensorless vector control calculation means

Claims (16)

In an inverter control device having motor constant correction calculation means for correcting a motor constant error of an AC motor and motor constant correction initial value setting means for setting an initial value of the motor constant correction calculation means at the time of starting the inverter,
The motor constant correction initial value setting means determines a motor constant correction value that is an output of the motor constant correction calculation means based on a cooling characteristic of the AC motor while the inverter is stopped. An inverter control device comprising: interpolating to be within a predetermined range, and setting the interpolated motor constant as an initial value of a motor constant correction value when the inverter is restarted. A PWM inverter that converts a DC voltage into an AC voltage; at least one AC motor driven by the AC voltage generated by the PWM inverter; and current detection means that detects an AC current flowing into the AC motor; Coordinate conversion means for converting the alternating current detected by the current detection means into direct current, current command generation means for generating a command value for the direct current converted by the coordinate conversion means, and speed information of the AC motor Speed detecting means for detecting, voltage information for driving the AC motor from speed information detected by the speed detecting means, a current command generated by the current command generating means, and a direct current converted by the coordinate converting means A vector control calculation means for generating a command and a voltage phase; and an electric power generated by the vector control calculation means. In the inverter control device having a PWM control operation unit for generating a switching instruction to the PWM inverter by pulse width modulation using a command and a voltage phase,
Motor constant correction calculation means for automatically correcting an error between the motor constant design value of the vector control calculation means and the motor constant of the AC motor, and initial values of the motor constant correction calculation means when the PWM inverter is started Motor constant correction initial value setting means for performing, while the PWM inverter is stopped, the motor constant correction initial value setting means outputs the motor constant correction value output from the motor constant correction calculation means to the AC motor. Interpolating so as to be within a predetermined range of the motor constant correction value determined based on the cooling characteristics of the motor, and setting the interpolated motor constant as an initial value of the motor constant correction value when the PWM inverter is restarted Inverter control device. In the inverter control device according to claim 1 or 2,
The motor constant correction initial value setting means sets the motor constant correction value so that it falls within a range between a lower limit value and an upper limit value of the motor constant correction value corresponding to the state of the AC motor while the inverter is stopped. An inverter control device characterized by performing interpolation. In the inverter control device according to any one of claims 1 to 3,
The motor constant correction initial value setting means interpolates a motor constant correction value, which is an output of the motor constant correction calculation means, based on an elapsed time from the inverter stop while the inverter is stopped. An inverter control device that is set as an initial value of a motor constant correction value.   4. The inverter control device according to claim 1, wherein the motor constant correction initial value setting means is a motor constant correction value that is an output of the motor constant correction calculation means while the inverter is stopped. Is set as an initial value of a motor constant correction value when the inverter is restarted, based on speed information immediately before the inverter is stopped. 3. The inverter control device according to claim 2 , wherein the motor constant correction initial value setting means always reads speed information from the speed detection means while the inverter is stopped, and the motor is based on the speed information at that time. An inverter control device characterized by interpolating a motor constant correction value, which is an output of a constant correction calculation means, and setting it as an initial value of a motor constant correction value when the inverter is restarted.   4. The inverter control device according to claim 1, further comprising temperature detection means for detecting temperature information of the AC motor, and based on the temperature information obtained from the temperature detection means, the motor temperature An inverter control device characterized by interpolating a motor constant correction value, which is an output of the motor constant correction calculating means, from the relationship between the motor constant and the motor constant, and setting it as an initial value of the motor constant correction value when the inverter is restarted. In the inverter control device according to any one of claims 1 to 7,
The motor constant correction initial value setting means sets the motor constant correction value, which is the output of the motor constant correction calculation means, while the inverter is stopped, the time change of the motor temperature depending on the motor cooling method, Interpolated so as to be within the range of the lower limit value and upper limit value of the motor constant correction value determined from the relationship between temperature change and motor constant change, and set as the initial value of motor constant correction value at inverter restart Inverter control device. In the inverter control device according to any one of claims 1 to 8,
The motor constant correction initial value setting means outputs the motor constant correction value, which is the output of the motor constant correction calculation means, while the inverter is stopped, the motor temperature change and the motor constant when the AC motor is stopped. Interpolate the motor constant so that it is within the range of the motor constant correction value determined from the relationship between the change and the motor constant correction value determined from the relationship between the motor temperature change and the motor constant change when rotating at the maximum speed. An inverter control device that is set as an initial value of a motor constant correction value at startup. In the inverter control device according to any one of claims 1 to 3,
8. The inverter control device according to claim 3, wherein the motor constant correction initial value setting means uses at least two or more of the features of the motor constant correction initial value setting means according to claims 3 to 7. In the inverter control device according to any one of claims 1 to 3,
When the inverter stop period is short, the motor constant correction initial value setting means holds the motor constant correction value, which is the output of the motor constant correction calculation means immediately before the inverter stop, while the inverter is stopped, and restarts the inverter. An inverter control device that is set as an initial value of a motor constant correction value at the time. The inverter control device according to any one of claims 1 to 11,
The motor constant correction initial value setting means interpolates only a correction value for a resistance error among motor constant correction values while the inverter is stopped. The inverter control device according to claim 6 ,
Instead of obtaining the speed information of the AC motor from the speed detection means, from the voltage operation amount inside the vector control calculation means, the current command generated by the current command generation means and the DC current converted by the coordinate conversion means An inverter control device using speed sensorless vector control for estimating speed information of the AC motor. In an inverter control device having motor constant correction calculation means for correcting a motor constant error of an AC motor and motor constant correction initial value setting means for setting an initial value of the motor constant correction calculation means at the time of starting the inverter,
While the inverter is stopped, the motor constant correction initial value setting means obtains the motor constant correction value, which is the output of the motor constant correction calculating means, the speed information immediately before the inverter is stopped, and the elapsed time since the inverter is stopped. Based on time, the motor constant change determined from the relationship between the motor temperature change and the motor constant change when the AC motor is stopped, and the motor when the AC motor is rotating at the maximum speed Interpolating to fit within the range between the change in temperature and the change in motor constant determined from the relationship between the change in motor constant, and setting the interpolated motor constant as the initial value of the motor constant correction value when restarting the inverter Inverter control device characterized. The inverter control device according to claim 14,
The motor constant correction initial value setting means, while the inverter is stopped, always reads speed information from the velocity detecting means, the motor constant correction motor constant correction which is an output of the calculation means on the basis of the times of speed information An inverter control device characterized by interpolating values and setting the initial value of a motor constant correction value when the inverter is restarted. The inverter control device according to claim 15 ,
Instead of obtaining the speed information of the AC motor from said speed detecting means, from the converted DC current by the current command and coordinate conversion means generated by the vector control calculating unit internal voltage operation amount and current command generating means An inverter control device using speed sensorless vector control for estimating speed information of the AC motor.

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