JPH0336178A - Inverter control device for elevator - Google Patents

Abstract

PURPOSE:To eliminate starting shock and instability of speed at the time of stopping retardation by providing a means for adding a torque boosting current equivalent to a torque-portion due to friction in the mechanical system of an elevator to a torque current command. CONSTITUTION:In a vector control calculation unit 7, a calculation unit 71 calculates the magnitude of a composite vector when a vector current command IT and an excitation current command I0 intersect at right angles to each other, to obtain a current command II. The current command II is added to a torque- boosting current IB by an adder 21, and II + IB serves as a conversion factor of a D/A converter 8. When starting the machine and stopping retardation, an electric motor is driven by the current obtained by adding the torque-boosting current IB to the current command II obtained from the torque current command IT and the excitation current command I0 to compensate for shortage of torque caused by friction in the mechanical system at the time of starting the machine and to restrict vibration produced at the time of putting the machine into a slow-speed operation for stopping the retardation by the torque-boosting current IB.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a control device for an elevator inverter having a current control system, and particularly to a current control device.

B1 Summary of the Invention The present invention has a current control system in the minor loop of the speed control system, and in controlling the inverter output current with a torque current command from the speed control system, the torque shortage due to friction in the mechanical system of the elevator is replaced by torque. By adding the boost current to the torque current command, it eliminates elevator start shock and speed instability during deceleration and stop.

C1 Conventional technology An elevator driving device using an inverter having a current control system has the configuration shown in FIG. 5, for example.

The inverter body 2 (which is supplied with DC power from the rectifier I)
A high voltage type inverter is input to the main circuit to moderately control the induction motor 3 which serves as the elevator drive source.

The control device compares the speed command N according to the speed pattern with the detected speed N5 from the speed detection pickup 4 of the electric motor 3 and the speed detection circuit 5, performs a speed control calculation using the speed control amplifier 6, and converts this output into a torque The excitation current setting position', r is determined by the vector control calculation unit 7 as the current command 11.
Orthogonal to o? II style command I + (=J I o'
+ I T') and the frequency command S that becomes the sine wave sample value
I NU (=S I N (6J.] (-φ)),
S I NV (-S I N (ωot+φ-2π/
3)) and convert these frequency commands into 1) / A converter 8
Current commands 1u and rw are obtained by converting them into analog signals and performing amplitude control according to current command 1, and compare these commands with the U and W phase output current detection signals of the inverter, respectively, to form a minor loop. Current control intensifier 91.
') 7 for 2 phases is pressure control Shinyumi ■. , V is obtained, and the V-phase voltage control signal is obtained through addition and inversion amplification of both signals, and the @voltage control signal 1□VvVw is modulated into a PWM waveform by the pulse width control circuit 11, and then the gate Gate control of the inverter main circuit 2 is performed by power amplification by the amplifier 12.

D Problems to be Solved by the Invention Conventional elevator drive devices have a configuration in which the speed control loop has a current control minor loop, and it is difficult to operate the repeating speed pattern of start-acceleration constant speed-deceleration-stop that is unique to elevators. There is no compensation for the torque generated by friction in the mechanical system during low-speed operation and startup, and as shown in Figure 6, there is a sudden speed change at the start of the actual speed shown by the broken line with respect to the speed command N shown by the solid line. This may cause a start shock accompanied by a sudden drop in speed, and speed instability such as vibrations just before the elevator decelerates, which may cause discomfort and anxiety to the passengers.

An object of the present invention is to provide an elevator inverter control device that eliminates start shock and speed instability during deceleration and stop.

81 Means and Function for Solving the Problems In order to achieve the above object, the present invention has a current control system in the minor loop of the speed control system, and controls the current based on the torque current command from the speed control system and the output current of the inverter. A control device for an elevator inverter that performs current control by a system includes an adding means for adding a torque boost current corresponding to a torque due to friction in the elevator mechanical system to the torque current command, and the control device controls the elevator mechanical system by the torque boost current. Compensates for the lack of torque due to friction.

The present invention also provides a gain adjustment means for reducing the torque boost current corresponding to the torque added to the friction of the mechanical system of the elevator as the elevator speed command increases, and a gain adjustment means for reducing the torque boost current corresponding to the torque added to the friction of the mechanical system of the elevator. The present invention includes an addition means for adding to the command, and increases torque compensation when the elevator starts, decelerates and stops, and performs insufficient torque compensation while eliminating excessive compensation at medium and high speeds.

F. Embodiment FIG. 1 is a main circuit diagram showing an embodiment of the present invention. The vector control calculation section 7 is configured similarly to that shown in FIG.
A calculation unit 7I calculates the magnitude of the composite vector when the vector current command ■1 and the excitation current command 1° are orthogonal to each other to obtain a current command II. Further, the calculation unit 72 calculates the phase angle φ by calculating the arctangent of both commands, and further, the calculation unit 73 performs differentiation to determine the phase change amount Δφ. In addition, the calculation unit 74 outputs both commands to, IT and the motor's secondary time constant r, (=r,,t
/Rt) to find the slip frequency ω8, and add the detected speed ω from the speed detector 5 to this in the adder 75 to obtain the operating frequency ω. seek. Then, in the sine wave generating section 7°, the phase change △φ and the operating frequency ω. By adjusting the access cycle and address of ROM data having a sine wave sample value, the desired sine wave sample string data is sequentially output. This output is S rNU=s IN (r, +.l:+φ)STNW
=STN(ωot+φ-2yr/3)→Noble 4n'i data string.

Next, the D/A converter 8 converts the outputs 1NU and 5INV of the vector calculation units 7 to 7 into analog signals to obtain the current commands υ, I, 1, and the current command T+ from the calculation unit 71. The amplitudes of current commands T u and I w are set to desired values by multiplying by coefficients.

Here, the current command I is added to the torque boost (torque boost) 14 and the flow IB in the adder 21, and the addition result T, +1.
is used as a conversion coefficient of the D/A converter 8.

This torque boost current In is given as a bias current value over the entire range from a low speed range to a high speed range, or only when the elevator starts and decelerates and stops.

Therefore, when the elevator starts and decelerates and stops, the torque current command I7 and the excitation current command ■. The electric motor 3 is driven by the current obtained by adding the torque boost current TB to the current command ■1 obtained from the current command, and compensates for the torque shortage caused by friction in the mechanical system at startup with torque 8 and boost current 18, and also decelerates and stops. Torque boost current I reduces vibration when entering low speed operation for
Suppressed by B.

The torque characteristics of the elevator mechanical system vary from speed zero to speed V, as shown in FIG. Static friction torque area and speed V up to. It is broadly divided into the windage torque range at maximum speed VMAX and the windage torque range at maximum speed VMAX. Torque compensation by the torque boost current In is mainly performed for torque shortage and torque excess due to static friction torque, and windage damage compensation in the medium and high speed range is performed. J: can be sufficiently compensated for in the speed control system. Also,
When the elevator is going down, the polarity of the torque current command rT is reversed when it is going up, but even at this time, the polarity of the torque booth) and current ■8 is not changed, and the torque command I when going down is the same.
7 (static friction torque) can be compensated for.

FIG. 3 is a main circuit diagram showing another embodiment of the present invention.

The difference between this diagram and Figure 1 is that the torque boost current ■8
The gain control amplifier 22 performs gain adjustment based on the speed command N, and this output TB' is provided as the addition torque boost current of the adder 21. The torque boost current In is adjusted by the gain control amplifier 22, as shown in FIG. Torque boost current I. 8.8, and its characteristics are set to be a constant ratio as shown by the solid line, or to be changed exponentially as shown by the broken line.

In this embodiment, the torque boost current command (8) is made lower as the elevator operates at medium and high speeds. As a result, the amount of torque boost compensation due to the torque boost current In during medium-to-high speed operation of the elevator is reduced, and the torque boost compensation in this operating range is prevented from becoming overexcited and causing vibration and noise generation. Is the inverter output voltage rising to near the power supply voltage and causing control instability? To obtain sufficient torque compensation at the time of starting and deceleration/stop while preventing the occurrence of such vibration.

Although the embodiment shows a case using vector control, the present invention can be applied to a slip frequency control device or the like to obtain the same effect.

G1 Effects of the Invention As described above, according to the present invention, since the torque current command minus the strike current corresponding to the l-lux due to friction in the elevator mechanical system is added to the torque current command, the start It is possible to perform torque compensation that prevents shocks and vibrations during deceleration and stop. Furthermore, since the torque boost current is made smaller as the speed increases according to the elevator speed command, it is possible to prevent start shock and vibration while eliminating excessive torque compensation in high speed and medium speed ranges.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram of a main part showing one embodiment of the present invention, Fig. 2 is a speed-mechanical torque characteristic diagram of an elevator, and Fig. 3 is a circuit diagram of a main part showing another embodiment of the invention. 4 is a torque boost current characteristic diagram in FIG. 3, FIG. 5 is a configuration diagram of the elevator drive device, and FIG. 6 is a speed waveform diagram of the elevator. 2...Speed detection circuit, 7...Vector control calculation unit, -D/A converter,...Adder, 22...Gain adjustment circuit. 2 people outside

Claims (2)

[Claims] (1) Has a current control system in the minor loop of the speed control system,
In an elevator inverter control device that performs current control using a current control system based on a torque current command from a speed control system and an output current of an inverter, a torque boost current corresponding to the torque due to friction in the elevator mechanical system is applied to the torque. 1. A control device for an elevator inverter, comprising an addition means for adding to a current command. (2) Has a current control system in the minor loop of the speed control system,
In an elevator inverter control device that performs current control by a current control system based on a torque current command from a speed control system and an output current of an inverter, a torque boost current corresponding to the torque due to friction in the elevator mechanical system is applied to the elevator speed. 1. A control device for an elevator inverter, comprising: gain adjustment means that decreases the command as the speed increases; and addition means that adds the torque boost current adjusted by the gain adjustment means to the torque current command.