JPH0530747B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a control device for a rope elevator driven by an induction motor.

[Conventional technology and problems]

An induction motor (hereinafter referred to as a motor) is used as the electric motor that drives the elevator car, and an inverter is used as the power source to control the secondary magnetic flux and slip frequency of the motor, thereby controlling the torque generated by the motor. There is something that makes you want to drive.
In this case, the inverter is usually subjected to PWM control because it is necessary to reduce the torque ripple of the motor.
However, when PWM control is performed, the high frequency component of the motor current increases near the PWM switching frequency, resulting in large noise and vibration. One way to reduce this noise and vibration is to change the motor's secondary magnetic flux according to the load. In other words, when the load is large, the motor's secondary magnetic flux is operated near the rated magnetic flux, and when the load is small, the motor's secondary magnetic flux is There are ways to reduce this while driving. This is because the torque generated by a motor is proportional to the product of secondary magnetic flux and torque current, as described later, whereas motor noise and vibration roughly depend on the size of secondary magnetic flux and are not dependent on the size of torque current. The aim is to take advantage of this independence and reduce the noise and vibration of the motor when the load is light, thereby creating a quiet elevator.

Now, the torque generated by the motor is T, the component in the vector direction of the secondary magnetic flux Φ ₂ of the primary current I ₁ (hereinafter referred to as exciting current) is I _M , the component orthogonal to I _M (hereinafter referred to as torque current) is I _T , The mutual inductance between the primary and secondary windings of the motor is M, the secondary self-inductance is L ₂ , the secondary resistance is R ₂ , the slip angular frequency is ω _S , and the command values of the above parameters are each parameter. The following relational expression is established between these parameters T, Φ ₂ , I _M , I _T , I ₁ , M, L ₂ , R ₂ , and ω _S. To establish.

I _M =Φ ₂ /M+L ₂ /M・R ₂ d/dtΦ ₂ …(1) ω _S =R ₂・M/L ₂・Φ ₂ I _T …(2) T=M/L ₂ Φ ₂ I _T (3) I ₁ =√ _T ² + _M ² (4) Therefore, in order to generate the desired torque T in the motor, the control circuit is configured to satisfy the above relationship.

That is, I _M ^* = Φ ₂ ^* M + L ₂ / M・R ₂ d/dtΦ ₂ ^* ……(5) I _T ^* = L ₂・T ^* /M・Φ ₂ ^* ……(6) I ₁ ^* =√ _T ^*2 + _M ^*2 ...(7) ω _S ^* = R ₂ T ^* /Φ ₂ ^*2 ...(8) The control circuit configured based on this relationship is
As shown in the figure. The above-mentioned symbols in FIG. 2 indicate the same ones as above, except that R, S, and T are three-phase power supply circuits, 1 is a motor that drives the elevator car,
2 is a converter that converts three-phase AC power into DC variable voltage, C is a smoothing capacitor, 3 is an inverter that converts DC to variable frequency AC, 4 is a pulse encoder that detects the rotation speed of motor 1, and 5 is inverter control. A device 6 increases the deviation between ω _r ^* , which is the speed command of the elevator car converted into the angular velocity command (angular frequency command) of the motor 1, and the angular velocity (angular frequency) ω _r of the motor 1, which is converted by the pulse encoder 4. The speed regulator (hereinafter referred to as ASR) that outputs the width and torque command T ^* , 7 outputs an appropriate secondary magnetic flux command Φ ₂ ^* in consideration of both motor noise and motor torque according to the torque command T ^* . magnetic flux command generator,
8 is a mutual inductance setter, 9 is a secondary circuit time constant setter, 10 is a differentiator, 11 is a torque command
A divider that divides T ^* by the secondary magnetic flux command Φ ₂ ^* , 12 is
L ₂ /M setting device, 13 is secondary resistance R ₂ setting device,
14 is a divider that divides the output of the setting device 13 of the secondary resistance R ₂ by the secondary magnetic flux command Φ ₂ ^* and outputs the slip angle frequency command ω _S ^* ; 15 is the excitation current command I _M ^* and the torque current command A vector calculator that calculates the primary current command I ₁ ^* from I _T ^* , ω ₁ ^* is the primary current command that adds the slip angular frequency command ω _S ^* and the angular frequency ω _r of the motor 1 and inputs it to the inverter control device 5. This is the angular frequency command.

Since the functions of each part in the above configuration are well known, a detailed explanation will be omitted, but an outline of the operation of the circuit is as follows.

First, at the start of operation, an angular frequency command ω _r ^* is given, and the deviation from the angular frequency ω _r of the motor 1 obtained by converting the rotation pulse obtained from the pulse encoder 4 is amplified by ASR, and the torque command T Get ^* . Corresponding to the magnitude of this torque command T ^* , an appropriate secondary magnetic flux command Φ ₂ ^* is output by the magnetic flux command generator 7, which has a preset function, taking into account both motor noise and motor torque. be done. Using this torque command T ^* and secondary magnetic flux command Φ ₂ ^* , a primary current command I ₁ ^* and a slip angular frequency command ω _S ^* are generated through a circuit configured to satisfy equations (5) to (8) above. obtain. The slip angular frequency command ω _S ^* is added to the angular frequency ω _r of the motor 1 to obtain the primary angular frequency command ω ₁ ^* . In accordance with I ₁ ^* and ω ₁ ^* , inverter control device 5 supplies alternating current to motor 1, and motor 1 rotates in response to desired angular frequency command ω _r ^* . Note that, normally, in order to improve torque transient response, the angle formed by the primary current vector and the secondary magnetic flux vector is added to the primary angular frequency command route, but this is not directly related to the present invention and will therefore be omitted.

2 when the elevator starts with the configuration shown in Figure 2
Next, the movement of magnetic flux will be explained with reference to FIG.

At the same time as the start of operation, a torque command necessary to balance the rope tension between the elevator car and the counterweight is generated. For simplicity, it is assumed that the torque command is constant. Then, the secondary magnetic flux command Φ ₂ ^* also rises in a stepwise manner, and it is necessary to give the necessary excitation current command I _M ^* based on this using equation (5). However, since dΦ ₂ ^* /dt in equation (5) becomes infinite, I _M ^* that satisfies equation (5) cannot actually be commanded, and is limited by the current determined by the current capacity of the inverter main circuit. This results in a waveform of I _M ^* as shown in Figure 3. Therefore, the actual rise of the secondary magnetic flux Φ ₂ is delayed by the time t ₁ as shown in FIG. 3. During this delay time in the generation of magnetic flux, the motor generated torque decreases according to the secondary magnetic flux Φ ₂ as seen from equation (3), so the motor 1 is stretched by an unbalanced load, causing a so-called starting shock. Occur. The above has described a control device that makes the secondary magnetic flux command Φ ₂ ^* variable in accordance with the magnitude of the torque command T ^* .
Another conventional technique is a method in which the secondary magnetic flux command Φ ₂ ^* is kept constant (rated value) regardless of the size of the load. Even in this second prior art, if the secondary magnetic flux command is given at the same time as the start of operation, the rise of the actual secondary magnetic flux Φ ₂ will still be delayed for the same reason as described above. Therefore, in such a control method for keeping the secondary magnetic flux constant, a method has been proposed in which the secondary magnetic flux is raised to a predetermined constant value (rated value) before the elevator starts operating. However, when this method is applied to the aforementioned control method in which the secondary magnetic flux command Φ ₂ ^* is varied in accordance with the magnitude of the torque command T ^* , the magnitude of the secondary magnetic flux set before the start of operation is a constant value. On the other hand, since the secondary magnetic flux command Φ ₂ ^* after the start of operation is variable, a level difference in the secondary magnetic flux also occurs at the start of operation. This is shown in FIG. FIG. 4 shows a case where operation is started with a load torque corresponding to a lower secondary magnetic flux than the secondary magnetic flux set value (rated value) before the start of operation. In this case as well, Φ ₂ ^* changes stepwise with the start of operation, but since the direction of change is in the decreasing direction, the second term dΦ ₂ ^* /dt in equation (5) is negative infinity, and therefore I _M ^* is also Although it becomes negative infinity, it cannot actually become negative, so the actual secondary magnetic flux Φ ₂ decreases with a delay of time t ₂ . Therefore, during this period t ₂ , the magnetic flux Φ ₂ is larger than the predetermined value, so the motor noise and vibration during PWM control become large. Furthermore, since the magnetic flux Φ ₂ is larger than a predetermined value, a large starting torque is temporarily generated, resulting in a problem of so-called starting shock.

An object of the present invention is to provide an elevator control device that solves the problems of the prior art as described above.

[Means for solving problems]

The elevator control device according to the present invention includes a load detector that detects the load inside the car, and an initial torque that outputs the motor torque necessary to balance the rope tension caused by the car and the counterweight according to the output of the load detector. It is equipped with a setting device and a magnetic flux command generator that outputs an appropriate secondary magnetic flux command according to the torque command.The input of the secondary magnetic flux command generator is connected to the initial torque setting device before the start of operation, and immediately after the start of operation. By providing a switching device that switches and connects to the speed regulator, sudden changes in Φ ₂ before and after the start of operation are prevented, and an elevator control system that is free from the above-mentioned problems is obtained.

〔Example〕 An embodiment of the present invention is shown in FIG.

The same parts as in Fig. 2 are designated by the same reference numerals and their explanations will be omitted. An initial torque setter 17 and a switching device 18 are added to output the motor torque T ₀ necessary to balance the rope tensions due to the lever and counterweight. The switching device connects the input of the magnetic flux command generator 7 to the initial torque setter side before the start of operation, and to the ASR output side at the same time as the start of operation. Figure 5 shows the response of the secondary magnetic flux at the start of operation with the configuration shown in Figure 1 when the load is light as seen from the motor.
FIG. 6 shows a heavy case. When the excitation current is raised in steps, the magnetic flux response delay is 0.2
It takes approximately 0.4 seconds to confirm the initial setting torque.
In other words, the car load signal is determined when the car door is closed, and if the exciting current command I _M ^* is started at this point and the magnetic flux is started, the secondary magnetic flux Φ ₂ will be steady when the elevator starts operating. Since this state has been reached, the start-up shock due to the response delay of the magnetic flux explained in FIGS. 3 and 4 and the motor noise and vibration during PWM control do not occur. Immediately after the start of operation, the secondary magnetic flux command Φ ₂ ^* temporarily drops during the rise time of T ^* , but this time is short and does not affect actual use.

In addition, in the embodiment shown in Fig. 1, a calculation method using motor constants was shown as a method for obtaining the excitation current command I _M ^* from the secondary magnetic flux command Φ ₂ ^* . The deviation between the command Φ ₂ ^* and the detected magnetic flux value may be amplified by a magnetic flux regulator, and this output may be given as the excitation current command.

〔Effect of the invention〕

According to the present invention, it is possible to obtain an elevator control device that provides an extremely comfortable ride with less starting shock at the start of operation, less vibration and noise of the motor based on PWM control.

[Brief explanation of the drawing]

FIG. 1 is a control circuit diagram showing one embodiment of the present invention;
Figure 2 is a conventional control circuit diagram, Figure 3 is a diagram showing the response of the secondary magnetic flux when a step-like torque command is given with the circuit configuration of Figure 2, and Figure 4 is a conventional control circuit diagram. A diagram showing the secondary magnetic flux response after the start of operation when a constant secondary magnetic flux command is given before the start of operation. Figure 5 shows the control circuit of Figure 1 before and after the start of operation when the motor load is light. FIG. 6 is a diagram showing the state of the secondary magnetic flux, etc. before and after the start of operation when the motor load is heavy in the control circuit of FIG. 1. 1... Motor, 2... Converter, 3... Inverter, 6... Speed regulator, 7... Magnetic flux command generator, 16... Load detector, 17... Initial torque setting device, 18... Switching device , T ^* ……torque command,
T ₀ ... Initial torque setting device output, Φ ₂ ^* ... Secondary magnetic flux command, I _M ^* ... Excitation current command.

Claims (1)

[Scope of Claims] 1. In a control device for a rope elevator that connects an inverter to a DC power source to convert the DC power to AC power, and drives an induction motor using the AC power to operate the car, the control device provides: an angular velocity command; a speed regulator that outputs a torque command by amplifying the deviation between the angular velocity of the induction motor and the angular velocity of the induction motor;
A magnetic flux command generator that outputs a secondary magnetic flux command in response to the magnitude of the torque command, a load detector that detects the load inside the car, and a rope tension between the car and the counterweight according to the output of the load detector. An initial torque setting device that outputs the motor torque necessary for balancing and the input of the magnetic flux command generator are connected to the initial torque setting device before the start of operation, and are switched and connected to the speed regulator immediately after the start of operation. An elevator control device comprising: a switching device.