JPH06329349A - Elevator control device - Google Patents

Abstract

PURPOSE:To prevent the generation of shortage in the voltage by furnishing a control command circuit which emits a modulation factor signal to control the output currents of a current type converter and a current type inverter, a circuit to control the output current of the converter with a modulation factor signal, and a circuit to control the pulse width of the output current of the inverter. CONSTITUTION:The AC current from a three-phase AC power supply 1 is converted into DC current by a current type converter circuit 12 and further converted into AC current by a current type inverter circuit 13, and an induction motor 51 is driven so that the elevator is controlled, A control command circuit 8 emits a modulation signal gamma to control the output currents of the converter 12 and inverter 13. The modulation factor signal gamma is fed to a pulse width control circuit 7 so that the pulse width of the output current of the inverter 13 is controlled, and pulses P1-P6 are emitted. The ratio Ic/gamma with the current command is computed by a computer 9, and the output current of the converter 12 is controlled through a current control circuit 10 and converter control circuit 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an elevator control device whose operation is controlled by an electric motor driven by a current source inverter device.

[0002]

2. Description of the Related Art Recent current-source inverter devices include, for example, SPC by the Institute of Electrical Engineers of Japan material (semiconductor power conversion workshop).
-86-47 (pp59-70), in order to reduce the harmonics of the output current, the DC current controlled by the current source converter is PWed by the current source inverter.
A method of controlling an alternating current in a sinusoidal shape by M pulse control has been proposed. According to this method, the harmonic content of the output current of the inverter can be reduced, and the noise and torque pulsation of the electric motor driven by this inverter can be reduced.

[0003]

In the method according to the above-mentioned proposal, in order to reduce noise and loss of the electric motor, PWM control is performed so that the signal waveform is close to a sine wave. Due to operation delay, etc.
The maximum value of the inverter output voltage is smaller than the inverter AC input voltage. Therefore, if the elevator is controlled by a general-purpose induction motor driven by the proposed current source inverter device, torque shortage may occur due to insufficient voltage, and the ride comfort of the elevator may deteriorate. For this,
Conventionally, a dedicated electric motor with a reduced rated voltage is designed and manufactured, and the proposed current source inverter device drives the electric motor to control the elevator to improve the control performance.

The present invention has been made on the basis of the current state of driving an electric motor by a current source inverter device as described above, and an object thereof is to prevent a shortage of voltage even if a general-purpose electric motor is used. An object of the present invention is to provide an elevator control device provided with an electric motor driven by a current source inverter device, which does not deteriorate the riding comfort of the elevator.

[0005]

In order to achieve the above object, the present invention provides a current source converter circuit for converting an alternating current from an alternating current power source into a direct current and a direct current obtained by the current source converter circuit. In an elevator controller provided with a current source inverter circuit for converting into an alternating current and an electric motor driven by the current source inverter circuit, controlling an output current of the current source converter and an output current of the current source inverter. A control command circuit that outputs a modulation rate signal, a pulse width control circuit that controls the pulse width of the output current of the current source inverter based on the modulation rate signal, and an output of the current source converter based on the modulation rate signal And a current control circuit for controlling the current.

[0006]

According to this structure, the current source converter circuit for converting the alternating current from the alternating current power source into the direct current, the current source inverter circuit for converting the direct current obtained by the current source converter circuit into the alternating current, and the current In an elevator controller provided with a motor driven by a current-type inverter circuit, a modulation rate signal is output from a control command circuit, and a pulse width control circuit outputs a current-source inverter circuit based on the modulation rate signal. Pulse width of the output current is controlled, and the output current value of the current source converter circuit is controlled by the current control circuit based on the modulation rate signal. By these controls, an alternating current is supplied from the current source inverter circuit to the electric motor so that the terminal voltage does not drop in accordance with the control conditions.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. Here, FIG. 1 is an explanatory diagram showing the configuration of the first embodiment, FIG. 2 is a characteristic diagram showing the operation of the first embodiment,
FIG. 3 is a block diagram showing the configuration of the main part of the second embodiment.

As shown in FIG. 1, one end of a reactor 2 is connected to each phase terminal of a three-phase AC power source 1, and the other ends of these reactors 2 are connected to a current source converter 1.
2 is connected to the reactor 2 and the current source converter 1
2 and the condenser 3 between the other end of each reactor 2.
1 are connected to each other. This current source converter 12
Has a configuration in which two sets of series-connected circuits of a transistor 15 and a diode 16 are connected in series between the other ends of the reactors 2, respectively, and the AC current supplied from the three-phase AC power supply 1 is a current source converter. It is converted into a direct current at 12.

The output terminal of the current source converter 12 is
It is connected to a current source inverter 13 via a reactor 4, and this current source inverter 13 has a diode 17 and a transistor 18 connected in series between input terminals.
Two sets of serially connected constituent element circuits are connected in parallel with each other, and the connection points of the two series connection circuits of each constituent element circuit are respectively set as output terminals of respective phases. is there. Further, a current detector 24 that detects the direct current Id output from the current source converter 12 is connected between the current source converter 12 and the current source inverter 13.

The output terminal of the current source inverter 13 is
A capacitor 32 is connected between each phase terminal of the induction motor 51 of the elevator mechanical device 5 and between each phase between the current source inverter 13 and the elevator mechanical device 5.
Are connected to each other. In this way, the direct current obtained by the current source converter 12 is converted into a sine wave three-phase alternating current by the current source inverter 13, smoothed by the capacitor 32, and supplied to the induction motor 51. . In the elevator mechanical device 5, the rotary shaft of the induction motor 51 is connected to the sheave 53, and the induction motor 51
An electromagnetic brake 52 and an encoder 57 are attached to the rotating shaft of the. Then, the car 55 and the counterweight 56 are fixed to both ends of the rope 54 wound around the sheave 53, and when the sheave 53 is rotationally driven by the induction motor 51, the car 55 moves up and down. It is designed to run up or down the road.

The operation control device 6 to which the speed signal and the position signal of the elevator are input as the operation signal from the encoder 57 performs the vector control calculation based on the operation signal to obtain the obtained current command Ix, phase command θx and It has a function of outputting the frequency command fx. Here, the phase command θx is a command related to the torque T desired to be generated in the induction motor 51, and the torque T is substantially proportional to tan θx. A pulse width control circuit 7, a control command circuit 8 and an arithmetic unit 9 are connected to the operation control device 6, and the control command circuit 8 is connected to the pulse width control circuit 7 and the arithmetic unit 9. , The pulse width control circuit 7 is a current source inverter 1
It is connected to 3. Then, from the operation control device 6, the phase command θx and the frequency command fx are sent to the pulse width control circuit 7.
Then, the frequency command fx is sent to the control command circuit 8 and the current command Ix is sent.
Are input to the arithmetic unit 9, respectively.

The control command circuit 8 has a function of inputting to the pulse width control circuit 7 and the arithmetic unit 9 a modulation rate signal γ which linearly decreases when the inputted frequency command fx exceeds a predetermined value f1. Have In addition, the pulse width control circuit 7
It has a function of inputting the PWM pulses P1 to P6 of the frequency fx and the modulation rate γ to the current source inverter 13 based on the input phase instruction θx, frequency instruction fx and modulation rate signal γ. Then, the current source inverter 13 is
By controlling the switching of the transistor 18 with the WM pulses P1 to P6, the DC current Id is distributed to each phase so that each phase current of the three-phase output becomes a sine wave.

On the other hand, the calculator 9 calculates Ix / γ on the basis of the modulation rate signal γ and the current command Ix to obtain Ix / γ.
The γ signal is input to the current control circuit 10 connected to the arithmetic unit 9, and the DC current Id detected by the current detector 14 is input to the current control circuit 10. In the current control circuit 10, the difference calculation between the Ix / γ signal and the direct current Id is performed, and the obtained calculation signal is the current control circuit 1
It is input to the converter control circuit 11 connected to 0, and the DC current Id is controlled from the converter control circuit 11.
Also, P is controlled so that the three-phase AC input current becomes a sine wave.
The WM pulse is input to the current source converter 12 as a current command.

Next, the operation control of the elevator according to the first embodiment will be described.

The operation control device 6 generates a speed pattern by a call signal from a floor (not shown), obtains a speed feedback signal of the speed control system from the speed pattern and the operation signal from the encoder 57, and controls the speed feedback signal. From the deviation, the current command Ix, the frequency command fx, and the phase angle command θx are output as vector control signals. When accelerating to a substantially constant acceleration, the torque required by the mechanical device 5 is constant, so that the current command Ix is substantially constant, and the frequency command fx is controlled to gradually increase corresponding to the speed command. Then, when the speed pattern reaches a steady value, the acceleration torque becomes zero, so the only torque required is the load torque, and the current command Ix decreases.
Further, since the induction motor 51 rotates due to the slip corresponding to the load, the speed is set by adding the slip angular frequency to the synchronous rotation angular speed determined by the constant frequency command fx.

By the way, when the car approaches a predetermined floor, a speed pattern in which the car decelerates and stops at a substantially constant acceleration is generated, and control similar to acceleration is performed. Therefore, the electric power required during elevator operation increases in proportion to the speed and reaches the maximum value at the end of acceleration or at the start of deceleration. Since the output current Im of the current source inverter 13 is controlled substantially in proportion to the required torque, the output voltage Em of the current source inverter 13 is substantially proportional to the frequency command fx.
In addition, the elevator has approximately half the rated load on the car 55.
Of the induction motor 5 during the ascending operation in the full load state, since it is balanced with the counterweight 56 when the load is loaded.
1 requires a running torque, and conversely, a braking torque is required during steady state during deceleration operation and during deceleration.

As shown in FIG. 2, PWM pulses P1 to P
Three-phase currents Iu, IV, Iw distributed and output by
Has a peak value equal to the direct current Id. The PWM pulse shown in the drawing is a pulse train in which the pulse width PW gradually increases or decreases in proportion to sin (Σwxt) every time τ about 1/16 of the fundamental wave period. Where w
x = 2πfx. When the modulation rate γ is defined as (maximum value of pulse width PW) / (time τ), the peak value of the fundamental wave component of the output current becomes equal to the modulation rate γ, and the effective value Im of the current is obtained.
Is given by the equation [1].

Im = γId / √ (2) [1] Since the fundamental wave component of the PWM pulse and the current Im are in phase, the current flowing through the induction motor 51 is smoothed by the capacitor 32. , A sinusoidal current including a fundamental wave and harmonics as shown by the dotted line. The same applies to the output voltage. The line voltages are Euv, Evw, and Ewu, and the phase angle θm between the line voltage Em and the current Im is determined by the load condition of the induction motor 51, the frequency command fx, etc. θm
= 0). Further, the DC circuit voltage becomes equal to the line voltage of the phase in which the transistor 18 forming the current source inverter 13 is conducting. Therefore, when the upper and lower arms of the same phase become conductive, the DC circuit is short-circuited and the voltage during this period becomes zero.

The average value Ed of the output voltage of the current source converter 12 is substantially equal to the average value of the pulsed voltage shown in the figure, and the current source converter 12 and the current source inverter 13 are provided.
The harmonic component contained in the DC circuit voltage of is absorbed by the reactor 4 of FIG. 1, and the DC current Id has a smoothed waveform as shown in the figure.

The voltage and current when the first embodiment is driven in a predetermined speed pattern have the following relationship.

The DC voltage of the current source inverter 13 is Ed,
The direct current is Id, the line voltage of the induction motor 51 is Em, the current is Im, and the power factor is cos θm.
If the loss of 3 is neglected, the input power is equal to the output power, and therefore the equation [2] is established.

EdId = √ (3) EmImcosθm [2] Further, the inverter output current Im in FIG. 2 is expressed by the equation [1], and therefore the following equation is established.

Em = √ (2) Ed / √ (3) γ cos θm [3] As is apparent from the equation [3], the terminal voltage Em of the induction motor 51 can be controlled based on the modulation rate signal γ. it can.

By the way, the control result by the vector control is as follows.

The torque of the induction motor 51 is T, the mechanical rotational angular velocity is wr, the number of pole pairs is p, the efficiency is η, the frequency command of the vector control system is fx, the current command is Ix, and the phase angle command is θx. Have been carried out sufficiently. In the circuit for controlling the output current Id of the current source converter 12 in FIG. 1, the current command Ix / γ is controlled so as to be equal to the detected current Id, and therefore the equation [4] is established.

Id = I / γ ... [4] Since the output of the induction motor 51 is wrT,
Formula [5] is established.

WrT = √ (3) ηEmImcosθm [5] Further, [6] and [7] are established with h and k as constants.

Im = hIx [6] T = kImcosθx [7] The voltage Em and the power factor cosθm described above are determined from the constant of the induction motor 51, the torque T, the frequency of the current, and the like.
It has no direct relationship with vector control.

From the expressions [1], [4] and [6], the constant h in the expression [6] is 1 / √ (2), and the modulation factor γ is γ = 1 in the expression [1].
It will be the same as what you did. That is, among the vector control commands from the operation control device 6, the current can be controlled according to the commands.

Equation [8] is obtained from equations [5] and [7].

Em = kwrcosθx / √ (3) ηcosθm [8] The voltage Em needs to have a large value as the mechanical rotation angular velocity wr increases as in the formula [8].

The expression [9] is obtained from the expressions [3] and [8].

Wr = √ (2) ηEd / γkcos θx [9] From the equation [9], the modulation factor γ = 1 and θ determined by the required torque.
x and other coefficients are constant, the mechanical rotation angular velocity wr
Is proportional to the DC voltage Ed. By the way, since the maximum value Edm of the output voltage of the current source converter 12 is the full-wave clear current average value of the voltage of the three-phase AC power supply 1, when Ed = Edm, w
r is the maximum value, and the motor voltage Em is insufficient beyond this. If the value of the frequency command fx at this time is f1, the first
In the embodiment, since the modulation factor γ is decreased at the frequency command f1 or more, the voltage Em can be increased from the equation [3], and since the voltage shortage does not occur, the induction motor 51 can have a large rated voltage. It is possible to perform various controls.

In the second embodiment, as shown in FIG. 3, instead of the control command circuit 8 of the first embodiment shown in FIG. 1, a control command circuit 8A for outputting a constant modulation rate signal γn is provided. The configuration of the other parts of the second embodiment is the same as that of the first embodiment already described. This modulation rate γn is
The value is selected so that the voltage does not drop when the frequency and the required torque increase.

Also in the second embodiment, the DC voltage Ed is γn times the Em when γn = 1 from the relation of the equation [3]. Since the direct current Id is controlled as described above, the direct current voltage of the current source converter 12 is similar to γn.
And the speed control system operates in the same way as in the case of FIG.
Good control is performed even if the rated voltage of the induction motor 51 is large without causing a voltage shortage.

[0036]

As described above, according to the present invention, the modulation rate signal is output from the control command circuit, and the pulse width control circuit outputs the output signal of the current source inverter based on the modulation rate signal. Pulse width is controlled, and the current control circuit controls the output signal of the current converter based on the modulation rate signal, so that a voltage shortage occurs even if a general-purpose electric motor with a large rated voltage is used. Without this, it becomes possible to perform elevator control with a good ride comfort.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a configuration of a first exemplary embodiment of the present invention.

FIG. 2 is a characteristic diagram showing the operation of the first embodiment.

FIG. 3 is a block diagram showing a configuration of a main part of a second embodiment of the present invention.

[Explanation of symbols]

 1 Three Phase AC Power Supply 6 Operation Control Device 7 Pulse Width Control Circuit 8 Control Command Circuit 9 Computing Unit 10 Current Control Circuit 11 Converter Control Circuit

Claims (2)

[Claims] 1. A current source converter circuit for converting an alternating current from an alternating current power source into a direct current, a current source inverter circuit for converting a direct current obtained by the current source converter circuit into an alternating current, and this current source inverter circuit. In an elevator control device including a motor driven by, a control command circuit that outputs a modulation rate signal that controls the output current of the current source converter and the output current of the current source inverter, and the modulation rate signal An elevator comprising: a pulse width control circuit for controlling a pulse width of an output current of the current source inverter based on the current source; and a current control circuit for controlling an output current of the current source converter based on the modulation factor signal. Control device. 2. The elevator control apparatus according to claim 1, wherein the control command circuit outputs a modulation rate signal having a characteristic that decreases when the frequency command of the elevator operation signal is equal to or higher than a predetermined value.