JP2008280107A - Motor control device for elevator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily and accurately control terminal voltage and current of a motor to regulated values without requiring the complicated adjusting work by a worker. <P>SOLUTION: The motor control device for elevator, which controls drive of a motor 3 with a vector control method, comprises an automatic control constant adjusting section 18 for automatically adjusting a vector control constant so that the terminal voltage and current in the rated load operation respectively becomes a regulated value by using a predetermined calculation formula based on measured values of the terminal voltage, current and rotating speed of the motor 3 to be obtained in at least two different operating condition. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electric motor control device for driving and controlling an induction motor used in an elevator hoisting machine.

  In general, when an induction motor is used for an elevator hoist, so-called “slip frequency type vector control” is often performed. In order to obtain good control performance with this slip frequency vector control, the values of the mutual inductance and the secondary time constant are required among the electrical constants of the induction motor (for example, see Non-Patent Documents 1 and 2). ).

Here, the mutual inductance is necessary to determine the magnetic flux current command, and mainly affects the terminal voltage of the motor. The secondary time constant is necessary to determine the slip frequency command, and mainly affects the electric current of the motor.
The Institute of Electrical Engineers of Japan "Revised electromechanical engineering", Ohmsha, November 20, 1985, page 367 Yoshiaki Tamura and Shigeru Tanaka “Energy Conversion Application System” Maruzen December 87, 2000, pages 87 and 142

  In the case of an induction motor designed with vector control in mind, the values of the mutual inductance and secondary time constant described above can be easily known as design values. However, these constants are often unknown when reusing old induction motors in renewal properties, for example. For this reason, in order to set the terminal voltage and current of the motor to the specified values, the operator must adjust the values of the mutual inductance and secondary time constant used in the control device by trial and error. A great deal of time and effort was spent on the adjustment work.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an elevator motor control device that can easily and accurately adjust the terminal voltage and current of an electric motor to specified values without requiring troublesome adjustment work by an operator. And

  The elevator motor control device according to the present invention is an elevator motor control device that controls the drive of a motor by a vector control method, and is based on measured values of terminal voltage, current, and rotational speed of the motor obtained in at least two different operating states. The control constant automatic adjusting means is provided for automatically adjusting the vector control constant so that the terminal voltage and current at the rated load become the prescribed values according to the above formula.

  In the elevator motor control apparatus according to the present invention, the control constant automatic adjustment means includes a first adjustment means for performing adjustment processing on the terminal voltage of the electric motor during no-load operation, and an electric motor of the electric motor during full-load operation. Second adjusting means for adjusting the current.

  Further, the first adjusting means calculates a vector control constant of the magnetic flux current from a voltage average value in a constant speed region during no-load operation and a voltage target value during no-load operation.

  The first adjusting means uses a value calculated from the rated voltage, rated current and nominal value of the winding impedance of the motor as the voltage target value during the no-load operation.

  The first adjusting means calculates a weight load amount for setting the electric motor to the no-load state from the power consumption and the rotational speed at the constant speed when the electric motor is not in the no-load state.

  The first adjusting means uses values normalized as the power consumption and the rotation speed.

  The first adjusting means obtains the power consumption amount and the rotational speed from values of both the upward traveling and the downward traveling.

  The first adjusting means corrects the measured value of the terminal voltage of the motor with a value calculated from the effective current of the motor and the nominal value of the winding impedance when the motor cannot be completely unloaded. To do.

  The first adjusting means estimates the terminal voltage during no-load operation by calculation from the measured value of the terminal voltage when operated under two kinds of load conditions when the electric motor cannot be completely unloaded. .

  The first adjusting means sets the two types of load conditions as an up operation and a down operation with the same weight loading amount.

  The second adjusting means calculates a value of a vector control constant for obtaining a slip frequency from the torque current average value and the torque current rated value in the constant speed region during full load operation.

  The second adjusting means calculates an average torque current value in a constant speed region during full-load operation using values for both upward traveling and downward traveling.

  The second adjusting means obtains a slip frequency by using an average value for a very short time instead of calculating an average torque current value in the constant speed region during full load operation. Update the vector control constant twice or more during constant speed operation.

  The control constant automatic adjustment means uses an inverter voltage command value instead of the actual measurement value of the terminal voltage of the electric motor.

  According to the present invention, the terminal voltage and current of an electric motor can be easily and accurately adjusted to specified values without requiring troublesome adjustment work by an operator.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a diagram showing a system configuration of an electric motor control device using a vector control method according to a first embodiment of the present invention.

  In this motor control apparatus, the induction motor 3 is driven by converting a DC voltage obtained by a DC power source 1 such as a rectifier into an AC having a variable frequency and a variable voltage by an inverter 2. As shown in FIG. 2, an elevator hoisting machine 21 is directly connected to the induction motor 3. When the induction motor 3 is driven, the hoisting machine 21 is rotated accordingly, and the elevator car 23 and the counterweight 24 are suspended in the hoistway via the rope 22 wound around the hoisting machine 21. It moves up and down.

  When the induction motor 3 is being driven, the rotational speed of the induction motor 3 is detected by the speed sensor 4. The rotational speed of the induction motor 3 detected by the speed sensor 4 is input to a speed controller 6 including a proportional integral element together with a speed target value generated by the speed pattern generation unit 5. The output of the speed controller 6 is used as a torque current command value in vector control.

  Further, the current of the induction motor 3 is detected by the current detector 7. The current of the induction motor 3 detected by the current detector 7 is decomposed into a torque current component and a magnetic flux current component by a coordinate converter 8, and a torque current command value and a magnetic flux current setting device 9 that are outputs of the speed controller 6. Is input to the current controller 10 including a proportional integral element. The output of the current controller 10 is converted into a three-phase voltage command value to the inverter 2 by the coordinate converter 11 and becomes a gate signal of the inverter 2 by the PWM pattern generator 12.

  Here, in the slip frequency vector control, the electrical angle information used for the coordinate converters 8 and 11 is obtained by the following method.

  First, the divider 13 divides the torque current command value by the magnetic flux current command value. The slip frequency command value is obtained by multiplying the result by the inverse of the secondary time constant obtained by the secondary time constant inverse number setter 14.

  Next, the adder 15 adds the speed signal of the induction motor 3 to the slip frequency command value to obtain the operation frequency command value of the inverter 2. When this operating frequency command value is converted into an electrical angle by the integrator 16, electrical angle information used for the coordinate converters 8 and 11 is obtained.

  In such a slip frequency vector control, in order to obtain a specified terminal voltage and current at the rated load, it is necessary to adjust the mutual inductance and the secondary time constant to appropriate values. Usually, the operator manually adjusts the intuition and experience, but the motor control device of the present embodiment is provided with an automatic control constant adjusting unit 18 as a function for automating this adjustment.

  The control constant automatic adjustment unit 18 receives the signals of the speed sensor 4, the current detector 7 and the voltage detector 17, and actually measures the terminal voltage, current and rotational speed of the induction motor 3 obtained in at least two different operating states. The vector control constant is automatically adjusted so that the terminal voltage and current at the rated load become the specified values according to a predetermined arithmetic expression from the value.

Hereinafter, the automatic adjustment method by the control constant automatic adjustment unit 18 will be described in detail with reference to FIG.
FIG. 3 is a flowchart showing a procedure of automatic adjustment by the control constant automatic adjustment unit 18.

  First, a temporary vector control constant is set (step S11). In addition, the weight loading amount of the elevator is adjusted so that the induction motor 3 is in a no-load state during the constant speed operation (step S12). This state is called a balance load (hereinafter abbreviated as BL).

  The induction motor 3 is operated in the BL state, and the vector control constant for the magnetic flux current setter 9 is calculated and updated from the motor terminal voltage at the constant speed. Then, the operation is performed again with the updated value, and the operation and the update of the vector control constant are repeated until the motor terminal voltage enters a predetermined error range (for example, ± 5%) with respect to the target value (steps S13 to S13). S15).

  When the adjustment with respect to the magnetic flux current setting device 9 is completed, in order to perform the adjustment with respect to the secondary time constant reciprocal setting device 14, first, a full load state is set by mounting a weight corresponding to the capacity (step S16). This state is called full load (hereinafter abbreviated as FL).

  The induction motor 3 is operated at the rated load in the FL state, and the vector control constant for the secondary time constant reciprocal number setting unit 14 is calculated and updated from the motor current at the constant speed. Then, the operation is performed again with the updated value, and the operation / vector control constant is repeatedly updated until the motor current enters a predetermined error range (for example, ± 10%) with respect to the target value (steps S17 to S19). .

(A) Automatic Adjustment Method in BL State The automatic adjustment method in the BL state will be described in detail.

When the BL state can be completely achieved, the induction motor 3 is in a no-load state during constant speed operation. At this time, all of the motor current is a magnetic flux current, and the amplitude of the motor terminal voltage is proportional to the amplitude of the magnetic flux current. When was run an elevator in this state, the motor terminal voltage average value _{V AVE0} in the constant speed area and the temporary set value of the flux current and _{I Dref0,} recommended values _{I dref} flux current setting, (1) Represented by

Note that the section for _obtaining the average value of V _AVE0 does not necessarily _extend over the entire constant speed region, and may be a partial section thereof.

Actually, the magnetic flux current I _dref and the terminal voltage V _AVE0 during no-load operation are not completely proportional to each other, and include some nonlinearity. Therefore, after the magnetic flux current is updated by the above equation (1), operation is performed again with the set value, and the terminal voltage of the induction motor 3 falls within the allowable error range with respect to the voltage target value during no-load operation. It is necessary to confirm that. If it is out of the permissible error range, the above operation / update of the constants is repeated until it falls within the permissible error range.

Here, it should be noted that the voltage target value V _NRM0 is not the rated voltage V _NRM of the induction motor 3 (at full load). Strictly speaking, the current at the rated load is I _qNRM , the winding inductance _{component of} the induction motor 3 is L _M , and the resistance component is R _M , which is obtained by the following equation (2).

However, the case of obtaining the above (2), the value of inductance L _M and the resistor R _M inevitably with nominal values, in the case of old induction motor 3 is often the value itself is unknown. Experimentally, it has been found that the target value V _NRM0 should be about 85 to 90% of the rated voltage V _NRM .

(B) Automatic Adjustment Method in FL State Next, an automatic adjustment method in the FL state will be described.

In the FL state, the rated load operation is performed in the ascending constant speed region. When the average torque current value in the constant speed region at this time is I _qAVE , the rated torque current is I _qNRM, and the initial value of the secondary time constant is T ₂₀ , the updated value of the secondary time constant is given by equation (3) expressed.

Note that the interval for _obtaining the average value of I _qAVE does not necessarily have to be the entire constant velocity region, and may be a partial interval.

  However, the relationship between the secondary time constant and the torque component current is far more nonlinear than the relationship between the magnetic flux current and the terminal voltage. For this reason, even if the secondary time constant is updated in the above equation (3), the current may not be within the allowable error range with respect to the rated value. In such a case, the operation of the elevator and the updating of the constants may be repeated until the torque current falls within the allowable error range with respect to the rated value.

  According to the above procedure, the vector control constant for setting the voltage / current at the rated load to a specified value can be automatically determined with the minimum necessary number of operations. Therefore, the adjustment time can be shortened and the work burden on the worker can be reduced.

(Second Embodiment)
Next, a second embodiment of the present invention will be described.

  The configuration in the second embodiment is the same as that in FIG. 1, and only the operation of the control constant automatic adjustment unit 18 is different. That is, in the first embodiment, it is necessary to adjust the weight amount to create the BL state, and the worker performs the adjustment. On the other hand, in the second embodiment, the control constant automatic adjustment unit 18 is configured to automatically calculate the weight amount for setting the BL state and give an instruction to the worker.

Specifically, the elevator is operated with a temporary vector control constant when the elevator is empty (no-loading state), and the average power consumption P _AVE in the constant speed operation section is obtained by the control constant automatic adjustment unit 18. In the following, the state in which the car 23 is empty is abbreviated as an NL (NoLoad) state.

The average power consumption P _AVE is obtained by taking the average value of the instantaneous power consumption of the induction motor 3 between the constant speed regions, but the section for obtaining the average value does not necessarily have to cover the entire constant speed region. Moreover, when there is a current detector on the DC side of the inverter 2, an average value of DC input power of the inverter may be used. In this state, the weight amount W to be mounted in order to set the induction motor 3 to a no-load BL state is as follows, where the speed in the constant speed region of the elevator is v (upward driving direction is positive): Desired.

In the above equation (4), the negative sign is attached to the right side because when the elevator is operated in the NL state, the operation is regenerative and the average power is negative. Note that when this calculation is performed in the downhill operation, the power running operation is performed and _PAVE is positive, but the speed v is negative and the entire right side is a positive value.

  The control constant automatic adjustment unit 18 presents the value of the weight amount W [kg] obtained by the above equation (4) to the worker. As a presentation method, for example, there is a method of using a display (not shown), but the method is not particularly limited. If the worker mounts a weight having a value closest to the presented value on the elevator, the NL state can be easily obtained.

  At this time, if the voltage / current is standardized in advance with the rated value of the induction motor 3, the power consumption also becomes the standard value with respect to the rated value. If the speed is also standardized by the rated value, the weight amount to be mounted can be obtained as a percentage with respect to the FL without conversion by gravitational acceleration, and the amount of calculation can be reduced.

In the case of an elevator, if the ascending / descending operation is performed with the same load capacity, theoretically, the absolute value of the average power in both should be the same and only the sign should be different. Depending on the relationship between the length and weight, the values may be different. In this case, the accuracy of calculation can be improved by using the average value of the absolute values of the up and down operations as the absolute value of the average power P _AVE . Specifically, the average power during an uplink operation P _{AVE_UP,} if the average power during the downlink operation and P _{AVE_DN,} in consideration of the fact that both signs are different, can be obtained as follows.

Further, since the weights mounted on the elevator at the time of adjustment each have a certain size, they can be adjusted only discretely. Therefore, even if an accurate weight amount for obtaining the BL state is obtained by the above-described method, the vehicle is actually mounted with a weight having a value slightly deviated therefrom. In this case, the BL state is not completely achieved, and a current corresponding to a small amount of torque flows. Therefore, it is necessary to correct the amplitude of the motor terminal voltage used for the magnetic flux current setting calculation. The correction formula in this case is expressed by the following formula, where the amplitude in the constant speed region of the motor terminal voltage at this time is V _AVE .

The magnetic flux current may be set by the following equation using V _AVE0 obtained by this equation (6).

However, the inductance L _M and the resistance R _M are often unknown even as described above. From experience, it is known that when a torque component current _Iq corresponding to the rated output flows, in the case of a general induction machine, the terminal voltage increases by about 15%.

  In a region where the torque component current is about an order of magnitude smaller than the rated current, assuming that the terminal voltage increase and the torque component current are in a proportional relationship, for example, when a torque component current of about 10% of the rated current flows. May be corrected assuming that the terminal voltage rise is about 1.5%.

Further, the terminal voltage at the time of no-load operation can also be estimated by calculation by operating under two kinds of load conditions and extrapolating or interpolating from both terminal voltages. If the terminal voltage V _{AVE1 is at} the torque _component current I _q1 and the terminal voltage V _AVE2 is at the torque component current I _q2 , it can be calculated by equation (8).

  In this case, if one of the two types of load conditions uses the data at the time of the weight calculation in the first step, the labor of unloading the weight can be saved.

  The two types of load conditions may be an up operation and a down operation with the same weight load. If the ascending operation is a power running, the descending operation is regenerative, and if the average of both voltages is considered, it is considered to coincide with the terminal voltage during no-load operation.

  By using the procedure as described above, the number of times of loading and unloading weights for creating the BL state can be minimized when adjusting the magnetic flux current set value. Thereby, the adjustment time can be further shortened, and the work load on the worker can be further reduced.

(Third embodiment)
Next, a third embodiment of the present invention will be described.

  The configuration in the second embodiment is the same as that in FIG. 1, and only the operation of the control constant automatic adjustment unit 18 is different. That is, in the first embodiment, when the value of the secondary time constant reciprocal number setting unit 14 is updated from the current value in the FL state, the average value of the torque current is theoretically calculated as the up operation and the down operation. The absolute values should be equal and only their polarity should be reversed. However, there are cases where the absolute values of the two differ due to the relationship between the friction loss of the mechanical system and the weight of the rope.

Therefore, in the third embodiment, the absolute value of the torque current average value I _qAVE is averaged as the absolute value of the I _qAVE for each of the ascending operation and the descending operation, and the same polarity is used as in the ascending operation. Thereby, accuracy can be increased.

In the first embodiment, the average value in the constant speed region is used as the torque current average value I _qAVE . However, since the relationship between the slip frequency and the torque current is highly non-linear, it may take time to converge in the constant update according to the above equation (3). Meanwhile, the torque current I _q fast response, for a typical induction motor, after updating the value of T _2, after several m seconds to several tens of m seconds is known to settle. Therefore, it is possible to use an average value for a very short time as the torque current average value _IqAVE .

Therefore, in the third embodiment, the vector control constant is updated twice or more during one constant speed operation. Thereby, the frequency | count of operation of the elevator for convergence of a vector control constant can be reduced. In this case, regardless of the recurrence formula of the above formula (3), for example, I _qAVE −I _qNRM is input to the proportional integration element, and the second-order time constant is continuously updated by the output, so that The speed can be increased.

  By using the above procedure, the vector control constant can be converged to the optimum value in a short time and the adjustment time can be shortened even in a region where nonlinearity between the slip frequency and the motor current is strong. .

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described.

  FIG. 4 is a diagram showing a system configuration of an electric motor control device using a vector control method according to the fourth embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the same part as the structure of FIG. 1 in the said 1st Embodiment, and the detailed description shall be abbreviate | omitted.

  4 is different from the configuration of FIG. 1 in that the voltage detector 17 is omitted and a voltage command value to the inverter 2 output from the coordinate converter 11 is used instead. In FIG. 4, the value after being converted into the three phases by the coordinate converter 11 is used, but the value of the magnetic flux axis / torque axis component before the conversion may be used. The configuration of the other parts is the same as in FIG.

  In such a configuration, the control constant automatic adjustment unit 18 inputs signals of the speed sensor 4, the current detector 7, and the coordinate converter 11 and automatically adjusts the motor terminal voltage and current at the rated load. In this case, if the inverter 2 and the induction motor 3 are directly connected, the same result can be obtained if the part calculated by using the motor terminal voltage in the first embodiment is directly changed to the inverter voltage command value. .

  By using the above configuration, the same effect as in the first embodiment can be obtained, and in addition, the detector for detecting the motor terminal voltage is omitted, and the cost is reduced accordingly. Can do.

  Note that the present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying the components without departing from the scope of the invention in the implementation stage. In addition, various forms can be formed by appropriately combining a plurality of constituent elements disclosed in the above embodiments. For example, some components may be omitted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

FIG. 1 is a diagram showing a system configuration of an electric motor control device using a vector control method according to a first embodiment of the present invention. FIG. 2 is a diagram showing a schematic configuration of an elevator to which the induction motor according to the embodiment is applied. FIG. 3 is a flowchart showing an automatic adjustment procedure by the control constant automatic adjustment unit in the embodiment. FIG. 4 is a diagram showing a system configuration of an electric motor control device using a vector control method according to the fourth embodiment of the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... DC power supply, 2 ... Inverter, 3 ... Induction motor, 4 ... Speed sensor, 5 ... Speed pattern production | generation part, 6 ... Speed controller, 7 ... Current detector, 8 ... Coordinate converter, 9 ... Magnetic flux current setting device DESCRIPTION OF SYMBOLS 10 ... Current controller, 11 ... Coordinate converter, 12 ... PWM pattern generator, 13 ... Divider, 14 ... Secondary time constant reciprocal number setter, 15 ... Adder, 16 ... Integrator, 17 ... Voltage detector , 18 ... Control constant automatic calculation section.

Claims (14)

In an elevator motor control apparatus that controls the drive of an electric motor by a vector control method,
The vector control constant is automatically adjusted so that the terminal voltage and current at the rated load become the specified values according to a predetermined arithmetic expression from the measured values of the terminal voltage, current and rotational speed of the motor obtained in at least two different operating states. An elevator motor control apparatus comprising an automatic control constant adjusting means. The control constant automatic adjustment means is
A first adjusting means for adjusting the terminal voltage of the electric motor during no-load operation, and a second adjusting means for adjusting the electric current of the electric motor during full-load operation. The elevator motor control device according to Item 1. The first adjusting means includes
3. The elevator motor control apparatus according to claim 2, wherein a vector control constant of the magnetic flux current is calculated from an average voltage value in a constant speed region during no-load operation and a voltage target value during no-load operation. The first adjusting means includes
4. The elevator motor control device according to claim 3, wherein a value calculated from a nominal value of the rated voltage, rated current and winding impedance of the motor is used as a voltage target value during the no-load operation. The first adjusting means includes
4. The elevator according to claim 3, wherein when the motor is not in a no-load state, a weight load amount for setting the motor in a no-load state is calculated from a power consumption amount and a rotation speed at a constant speed. Electric motor control device. The first adjusting means includes
6. The elevator motor control apparatus according to claim 5, wherein a standardized value is used as the power consumption and the rotational speed. The first adjusting means includes
6. The elevator motor control apparatus according to claim 5, wherein the electric power consumption and the rotational speed are obtained from both values of upward traveling and downward traveling. The first adjusting means includes
When the electric motor cannot be completely unloaded, the measured value of the terminal voltage of the electric motor is corrected with a value calculated from the effective current of the electric motor and the nominal value of the winding impedance. The elevator motor control device according to claim 3. The first adjusting means includes
4. The terminal voltage during no-load operation is estimated by calculation from the measured value of the terminal voltage when operated under two load conditions when the electric motor cannot be completely loaded. The elevator motor control apparatus described. The first adjusting means includes
The elevator motor control device according to claim 9, wherein the two load conditions are an upward operation and a downward operation with the same weight loading amount. The second adjusting means includes
The elevator motor control apparatus according to claim 2, wherein a value of a vector control constant for obtaining a slip frequency is calculated from a torque current average value and a torque current rated value in a constant speed region during full load operation. The second adjusting means includes
12. The elevator motor control device according to claim 11, wherein an average torque current value in a constant speed region during full load operation is calculated using both values of upward traveling and downward traveling. The second adjusting means includes
Instead of calculating the average value of torque current in the constant speed range during full load operation over the entire constant speed range, the update of the vector control constant to obtain the slip frequency is performed at a constant speed by using the average value for a very short time. 12. The elevator motor control device according to claim 11, wherein the control is performed twice or more during operation. The control constant automatic adjustment means is
2. The elevator motor control apparatus according to claim 1, wherein an inverter voltage command value is used instead of the actual measured value of the terminal voltage of the motor.

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