JPH0347074B2 - - Google Patents

Description

[Detailed description of the invention]

TECHNICAL FIELD OF THE INVENTION This invention relates to an improvement in a device for controlling the speed of an AC elevator. [Prior art] It is possible to operate a high-speed elevator by using an induction motor as the motor that drives the car and controlling the applied voltage to obtain smooth operating characteristics.
For example, as shown in US Pat. No. 3,866,097. A power running thyristor is inserted into each phase of a three-phase induction motor, and when the elevator requires power running torque, for example during acceleration operation due to heavy loads rising or light loads falling, the gates of the power running thyristors are turned off. Controllably applies variable voltage three-phase alternating current to the primary winding of the motor. On the other hand, when the elevator requires braking torque, for example during deceleration operation when a heavy load is lowered or a light load is increased, the braking thyristor connected to the two phases of the motor is controlled to apply DC voltage to the primary winding of the motor. supply In this way, the electric motor generates torque matching the load torque required by the elevator, and smooth variable speed control is performed. However, high-speed elevators with speeds of 150 m/min or higher often operate at speeds that are much lower than the rated speed, such as acceleration, deceleration, and partial speeds. Additionally, at startup, a so-called scale startup is performed in which the motor generates torque commensurate with the unbalanced torque due to the weight difference between the car and the counterweight before the brake is released, but in this case, the motor is operated at zero speed. Ru. In order to achieve such low speeds with the above control, it is necessary to reduce the voltage applied to the motor to increase slippage during power running, and to control the motor by flowing direct current to the primary winding of the motor during braking. . Since such operation is inefficient, long-term operation results in large energy losses. In addition, the above control has non-linearity in that the gain of the control system fluctuates depending on the rotation speed and torque of the motor, making it difficult to perform highly accurate control similar to that of a DC motor or efficient control. It is. [Summary of the Invention] The present invention improves the above-mentioned drawbacks by separating an induction motor into a field current component and a torque current component, performing vector control, and performing feedback control on the field current component or the torque current component. AC elevator speed control enables induction motors to be controlled independently in accordance with command values in the same way as DC motors, including field and torque, and a wide speed range from low to high speeds to be controlled with high precision. The purpose is to provide equipment. [Embodiment of the Invention] An embodiment of the invention will be described below with reference to FIGS. 1 to 28. In Fig. 1, R, S, and T are three-phase AC power supplies, and 1 is connected to AC power supplies R, S, and T, and the voltage can be varied by inputting primary voltage command values 32a to 32c and synchronous angular velocity signal 23a, which will be described later. Frequency AC output 1a~
Variable voltage/variable frequency control device (hereinafter referred to as VVVF device) that generates 1c and controls the instantaneous value of the primary current of the three-phase induction motor 2, 3-5 are AC outputs 1a-
A DC current transformer 6 generates DC outputs 3a to 5a corresponding to the instantaneous value of 1c, and 6 inputs a sin θ ₀ signal 25a and a cos θ ₀ signal 25b, which will be described later, to output the DC output 3a.
A three-phase/two-phase coordinate converter that converts ~5a into a field current component and a torque current component, where 6a is a field current component signal, 6b is a torque current component signal, and 7 is a motor 2.
A speed signal 7a directly connected to the rotation speed and proportional to its rotation speed.
8 is a driving sheave of a hoist driven by the electric motor 2, 9 is wound around the sheave 8, and a car 10 and a counterweight 11 are connected to each other. 12 is a load detector installed in the car 10 and generates a load signal 12a corresponding to the load inside the car; 13 is a scale circuit that inputs the load signal 12a and generates a scale command value 13a; 14 is a speed command value 14a is a speed command generation circuit; 15 is composed of two subtracters (FIG. 25); and 15 is a subtractor that subtracts a speed signal 7a and the output of a damping circuit 26, which will be described later, from the speed command value 14a and generates a deviation signal thereof; Reference numeral 16 denotes a speed control circuit which is composed of a delay/lead circuit shown in Fig. 27 and controls the deviation signal to be zero, 16a is a torque current component command value, and 17 is an adder (Fig. 24) and a subtractor. A subtracter is composed of two devices (Fig. 25), and adds the torque current component command value 16a and the scale command value 13a, subtracts the torque current component signal 6b and the output of a damping circuit 27, which will be described later, and generates a deviation signal. , 18 is a torque current component control circuit configured with a delay/lead circuit shown in FIG. 27 and controls the output of the subtracter 17 to be zero, 19 is a field command circuit that issues a field current component command value 19a, 20 21 is a subtracter that subtracts the field current component signal 6a from the field current component command value 19a and generates a deviation signal; 21 is a second subtracter;
The adder 2 consists of the delay/lead circuit shown in Figure 7.
A field current component control circuit 22 controls the field current component signal 6a and the torque current component signal 6b so that the output of 0 becomes zero, calculates the slip frequency by inputting the field current component signal 6a and the torque current component signal 6b, and generates the slip frequency signal 22a. An arithmetic circuit 23 is a slip frequency signal 22a and a speed signal 7.
24 is an integrator that integrates the synchronous angular velocity signal 23a and generates a rotation angle signal 24a. 25 is an integrator that inputs the rotation angle signal 24a and generates a sin θ ₀ signal 25a and a cos θ ₀ signal. A sin/cos converter that outputs a signal 25b, 26 is the 28th
The speed signal 7 is composed of the lead/lag circuit shown in the figure.
27 is a damping circuit that inputs the torque current component signal 6b and generates a damping signal;
28 and 29 are compensation circuits for preventing mutual interference between the field current component command value 19a and the torque current component command value 16a, and the compensation circuit 28 inputs the field current component signal 6a and the synchronous angular velocity signal 23a and outputs the compensation signal 28a.
The compensation circuit 29 generates the torque current component signal 6b.
and the compensation signal 29 by inputting the synchronous angular velocity signal 23a.
emits a. 30 is a torque current component control circuit 18
An adder 31 adds the output of the field current component control circuit 21 and the compensation signal 28a to generate a torque voltage component command value 30a, and a subtractor 31 subtracts the compensation signal 29a from the output of the field current component control circuit 21 to generate a field voltage component command value 31a. 32 is a torque voltage component command value 30a, a field voltage component command value 31a, a sin θ ₀ signal 25a and a cos θ ₀ signal.
It is a two-phase/three-phase coordinate converter that inputs the signal 25b and converts it into primary voltage command values 32a to 32c for each of the three phases. FIG. 2 shows the circuit of the VVVF device 1, and in the figure,
34 is a power running converter connected to AC power supplies R, S, and T, and a three-phase full-wave rectifier circuit is formed by thyristors 34A to 34F, 34Ag to 34Fg are gates of thyristors 34A to 34F, and 35 is a thyristor 35A to 35F. A three-phase full-wave rectifier circuit is formed, and the AC side is connected to the AC power supplies R, S, and T, and the DC side is connected to the DC side of the power running converter 34. 35Ag to 35Fg are the thyristors 35A to 35F. Gate, 36 is a smoothing capacitor connected to the DC side of the power running converter 34, 37 is a voltage detector consisting of a resistor connected to both ends of the smoothing capacitor 37, 37a is the output of the voltage detector 37, 38 is a synchronous angular velocity Input the signal 23a and the voltage detector output 37a to generate the synchronous angular velocity signal 23.
The ignition signals 38a to 38l are emitted according to the ignition signals 38a to 38l, and the ignition signals 38a to 38f are sent to the gates 34Ag to 34A, respectively.
34Fg, a gate circuit that provides firing signals 38g to 38l to gates 35Ag to 35Fg, respectively;
An inverter 9 is connected to both ends of the smoothing capacitor 36, and is composed of six transistors 39A to 39F, of which two transistors are connected in series and three sets are connected in parallel. 39Aa~39Fa are transistors 39A~39
The bases of F, 39a to 39f, are diodes connected in parallel to transistors 39A to 39F, respectively, and AC outputs 1a to 1c are generated from two connection points of transistors 39A to 39F, respectively. A base drive circuit 40 inputs the primary voltage command values 32a to 32c and provides base drive signals 40a to 40f to the bases 39Aa to 39Fa, respectively. 3 to 7 show the configuration of the gate circuit 38. In FIG. 3, 42 is an inverting amplifier with a gain of -1 (FIG. 22), 43 is a normal amplifier (FIG. 23),
4 is an operational amplifier, 44a is its output, 45 is a comparator whose output 45a becomes "H" when the input reaches a predetermined positive value (Fig. 29), and 46 is an output when the input reaches a predetermined negative value. A comparator (FIG. 30) in which 46a becomes "H", and _R1 to _R4 are resistors. Voltage detector output 37a is synchronous angular velocity signal 23a
, that is, when the voltage across the smoothing capacitor 36 is lower than the voltage command value, the added value is negative, but it is inverted by the operational amplifier 44 and output 4.
4a is positive. Therefore, the output 45a of the comparator 45 is "H" and the output 46a of the comparator 46 is "L".
becomes. In the opposite case, that is, when the voltage of the smoothing capacitor 36 is higher than the voltage command value, the added value is positive, but the output 4 of the operational amplifier 44
4a becomes negative. Therefore, the output 45a of the comparator 45 is "L", and the output 46a of the comparator 46 is "H".
becomes. The output 45a and the output 46a are used to operate either the power running converter 34 or the regeneration converter 35. In FIG. 4, 47 is an inverting amplifier with a gain of -1 (FIG. 22), and 48 and 49 are switch elements (for example,
HARRIS, HA201), 50 is an operational amplifier, 5
0a is its output, _R5 to _R7 are resistors, and _C1 is a capacitor. When signal 45a is "H", signal 4
4a is inverted and passes through the switch element 48, and the signal 4a is inverted and passes through the switch element 48.
When 6a is "H", signal 44a passes through switch element 49 as is. These signals are processed by the operational amplifier 50, resistors _R5 to _R8 , and capacitor _C1 .
Gain and phase compensation is performed. In FIG. 5, 51 is a transformer, 52 is a rectifier circuit connected to the secondary side of the transformer 51 and connected in a bridge,
53 is a Zena diode connected to the DC side of the rectifier circuit 52, 54 is a capacitor, and 55 is a gain of -1.
(Fig. 22), 56 and 57 are operational amplifiers, 58 and 59 are diodes for limiting the negative side voltage, 60 and 61 are transistors, and 60
a, 61a are their collector outputs, R ₁₀ ~ R ₂₁
is a resistor, +V is a semiconductor positive power supply, and -V is also a negative power supply. Note that the gate circuit 38 of FIG. 2 is provided with three sets of the circuits of FIG. 5 for R-phase to T-phase. Transformer 51, rectifier circuit 52, Zena diode 5
3. The circuit composed of the capacitor 54 and the resistors R ₁₀ to R ₁₁ is the same as the thyristors 34A to 34 in FIG.
This is a circuit that generates a power supply synchronous voltage for controlling the firing angle of F, 35A to 35F. For example, by applying R-phase and T-phase line voltages to the transformer 51, the R-phase thyristors 34A, 34D, 35
A synchronous voltage is obtained to control the firing angles of A and 35D. A substantially triangular voltage is generated by the rectifier circuit 52, Zena diode 53, and capacitor 54, and this serves as a reference value for the operational amplifier 56,
57. Operational amplifier 56, resistor R ₁₂ ,
A circuit consisting of R ₁₃ and a negative power supply -V, and a circuit consisting of an operational amplifier 57, resistors R ₁₄ , R ₁₅ and a positive power supply +V are configured such that biased voltages are input to the operational amplifiers 56 and 57, respectively. Therefore, comparators each having a hysteresis width are constructed. Therefore, for example, when the signal 50a has a positive value and exceeds the predetermined value of the triangular voltage, the output of the operational amplifier 56 becomes "H". At this time, the output of the operational amplifier 57 is "L". Conversely, when the signal 50a has a negative value and exceeds the predetermined value of the triangular voltage, the output of the operational amplifier 57 becomes "H". At this time, the output of the operational amplifier 56 is "L". When the output of the operational amplifier 56 becomes "H", the transistor 60 becomes conductive and the output 60a becomes zero voltage. On the other hand, transistor 6
1 is non-conductive, so the output 61a becomes a positive voltage. In FIGS. 6 and 7, 63 to 70 are diodes, 71 to 74 are pulse transformers, 75 to 78 are capacitors, 79 to 82 are transistors, and R ₂₂ to
R ₃₁ is the resistance. Note that although the figure shows only the R phase, the S phase and T phase are also configured in the same way. When the signal 45a is "H", that is, when the voltage of the smoothing capacitor 36 is lower than the voltage command value (during power running), the transistors 79 and 80 are conductive, and a positive voltage is applied to one end of the primary side of the pulse transformers 71 and 72. is applied. When the transistor output 60a becomes zero voltage, a current flows through the primary side of the pulse transformer 71 and the diode 63, so a pulse voltage is generated on the secondary side, and the thyristor 34A becomes conductive. At this time, since the transistor output 61a has a positive voltage, no current flows through the primary side of the pulse transformer 72, no pulse voltage is generated on the secondary side, and the thyristor 34D does not conduct. In this way, the power running converter 34 operates and increases the voltage of the smoothing capacitor 36. Further, when the signal 46a is "H", the transistor output 6
0a, 61a causes the pulse transformer 73 or 74 to operate, and the thyristor 35A or 35D to conduct. In this way, the regenerative converter 35 operates, and the smoothing capacitor 3
6 voltage is lowered. 8 and 9 show the configuration of the base drive circuit 40, and in FIG. 8, 84 is a triangular wave 84a with a constant frequency sufficiently higher than the frequency of the AC power supplies R, S, and T.
A triangular wave generator that oscillates, 85A to 85C are input
A comparator that compares A ₁ and input A ₂ and outputs "H" when input A ₁ input A ₂ , and output "L" when input A ₁ < input A ₂ (Fig. 31), 86A~ 86C
is a two-phase divider, 86AA to 86AC are NOT gates, 86AD is a resistor, 86AE is a capacitor, 8
6AF and 86AG are AND gates. The comparator 85A compares the primary voltage command value 32a and the triangular wave 84a, and when the primary voltage command value 32a is greater than or equal to the triangular wave 84a, the output becomes "H", so the output 85Aa of the comparator 85A is as shown in FIG. It becomes a waveform. Due to the operation of NOT gates 86AA to 86AC, when output 85Aa is "H", output 40a of AND gate 86AF becomes "H", and AND
The output 40d of the gate 86AG becomes "L". Also, when the output 85Aa is "L", the AND gate 86
The AF output 40a becomes "L", and the AND gate 8
The output 40d of 6AG becomes "H". That is,
Transistors 39A and 39D of inverter 39 are made conductive alternately. The same applies to the two-phase dividers 86B and 86C, and the outputs 40b and 40e alternately connect the transistors 39B and 39E to the output 4.
Transistors 39C and 39 by 0c and 40f
F is made conductive alternately. In this way, a voltage in which a sine wave is modulated into a triangular wave is applied to the motor 2. In FIG. 9, 84A is an AC power supply that emits a sine wave AC with a constant frequency sufficiently higher than the frequency of AC power supplies R, S, and T; 84B and 84C are Zena diodes;
84D is a capacitor, and 84E and 84F are resistors. The maximum value of the sine wave alternating current of the alternating current power supply 84A is limited by the Zener diodes 84B and 84C. A triangular wave 84a is obtained by delaying this by a delay circuit with a large time constant consisting of a capacitor 84D and a resistor 84E. FIG. 11 shows the configuration of the three-phase/two-phase coordinate converter 6, and in the figure, 88A and 88B each have a gain.

8C to 88E are inverting amplifiers with gains of -1/√6, -1/√6 and -1/√2 (Figure 22), respectively. ), 89A to 89C are adders (Fig. 24), 89D is a subtracter (Fig. 25), and 90A and 90D are multipliers (for example,
ANALOG DEVICES, AD533). Between the field current component signal 6a and torque current component signal 6b and the primary currents 3a to 5a of the motor 2,
As is well known, there is the following relationship. Here, i _d : field current component 6 a i _q : torque current component 6 b i _a -i _c : primary current 3 a - 5 a The coordinate converter 6 calculates this. FIG. 12 shows the configuration of the two-phase/three-phase coordinate converter 32. In the figure, 91A to 91D are multipliers similar to the multiplier 90A, and 92A and 92B are subtractors (the 25th
), 92C, 92D are adders (Fig. 24), 94
A and 94B each have a gain

[Formula] and 1/√2 non-rotating amplifier (Figure 23), 94C has a gain of -
This is a 1/√6 inverting amplifier (Fig. 22). Field voltage component command value 31a, torque voltage component command value 30a, and primary voltage command values 32a to 32c
As is well known, there is the following relationship between them. V _v = −1/√6(v _d cosθ−v _q sinθ) −1/√2(v _d sinθ+v _q cosθ) v _w =−1/√6(v _d cosθ−V _q sinθ) −1/√ 2 (v _d sin θ + v _q cos θ) where, v _u ~ v _w : Primary voltage command value 32a ~ 32
c v _d : Field voltage component command value 31a v _q : Torque voltage component command value 30 a The coordinate converter 32 calculates this. FIG. 13 shows the configuration of the compensation circuit 28, and in the figure,
96A and 96B are non-rotating amplifiers (FIG. 23) with gains of k ₁ and k ₂ , respectively, and 96C is a multiplier similar to the multiplier 90A. Torque voltage component command value 30a
The field current component that affects is expressed as K ₁ ×w ₀ ×i _d (here, K ₁ =k ₁ ×k ₂ , and w ₀ is the synchronous angular velocity).
The compensation circuit 28 calculates this. The torque voltage component is compensated by the output of the compensation signal 28a. FIG. 14 shows the configuration of the compensation circuit 29, and in the figure,
97A and 97B are non-rotating amplifiers (FIG. 23) with gains of k ₃ and k ₄ , respectively, and 97C is a multiplier similar to the multiplier 90A. The torque current component that affects the field voltage component command value 31a is expressed as K ₂ ×w ₀ ×i _q (here, K ₂ =k ₃ ×k ₄ ). The compensation circuit 29 calculates this. The field voltage component is compensated by the compensation signal 29a which is the output thereof. FIG. 15 shows the configuration of the slip frequency calculation circuit 22, in which 98 is a divider (for example, ANALOG
DEVICES, AD533), 99,100 is an operational amplifier, and _R35 to _R40 are resistors. The slip frequency w _s is calculated as follows. w _s = K ₃ i _q / i _d However, K ₃ is a constant In other words, the divider 98 uses the field current component signal 6a
and torque current component signal 6b to calculate i _q /i _d ,
A constant K ₃ is added by a circuit consisting of an operational amplifier 99 and resistors R ₃₅ and R ₃₆ and is inverted to become a negative value.
Furthermore, this is inverted by the operational amplifier 100 to become a positive value, and a slip frequency signal 22a is output. FIG. 16 shows the configuration of the sin/cos converter 25,
In the figure, 101 is an A/D converter (for example, BURR BROWN, ADC80) that inputs the rotation angle signal 24a and converts it into a digital value, and 102 is the digital value of cos θ ₀ for each rotation angle θ ₀ . Cosine ROM stored in (for example, INTEL,
i2716), 103 is a sine ROM in which the value of sinθ ₀ is also stored, and 104 and 105 are D/A converters (for example,
BURR BROWN, DAC80). The value of cos θ ₀ for the rotation angle θ ₀ represented by the rotation angle signal 24a is obtained from the cosine ROM 102 and
The value of sinθ ₀ is read from the sine ROM 103, converted to an analog value, and the cosθ ₀ signal 25b
and sin θ ₀ signal 25a. FIG. 17 shows the configuration of the speed command circuit 14. In the figure, E is a DC power supply, S ₁ to S ₄ are closed sequentially with a start command, and when a deceleration command is issued, they are closed each time the car 10 passes a predetermined position. Acceleration/deceleration relay contacts are opened in sequence, _R41 to _R48 are resistors, and _C3 and _C4 are capacitors. During acceleration, when contacts S ₁ to _{S 4} are closed sequentially, the resistance
_R41 to _R44 are short-circuited in sequence, and the speed command value 14a becomes an acceleration command value that gradually increases as shown by a curve 14a1 in FIG. When acceleration ends, curve 14a2
This is a constant speed command value that maintains a constant value as shown in . During deceleration, when contacts S ₄ to _{S 1} are sequentially opened, resistors R ₄₄ to _{R 41} are sequentially inserted, so curve 14a
The deceleration command value gradually decreases as shown in 3. FIG. 19 shows the configuration of the field command circuit 19, in which W is a field weakening relay contact that is closed when performing field weakening, and N is a reference field relay contact that is closed when performing reference field. , S is a field-strengthening relay contact that is closed when field-strengthening is performed, and R ₄₉ to _{R 52} are resistances. When any one of the contacts W, N, and S is closed, a field current component command value 19a determined by the resistors R ₄₉ to _{R 52} is output. This value is E×R ₅₂ /R ₅₀ +R _{51 +R 52 when contact W is closed, ExR 52 /R 51} +R ₅₂ when contact N is closed, and E×R ₅₂ /R ₅₁ +R ₅₂ when contact S is closed. When it is done, it becomes E. FIG. 20 shows the configuration of a weighing device, which is described, for example, in FIG. 6 of US Pat. No. 3,614,996. Basket 10
The car frame 10a is suspended from the main cables 9, and the car chamber 10c is supported by an elastic body 10b on the car frame 10a. When the load inside the car 10c changes, the load detector 12 generates a load signal 12a corresponding to the change. The scale circuit 13 issues a scale command value 13a as shown in FIG. 21 in response to the load signal 12a. In other words, the scale command value 13a is zero when the load is 50%, and is a positive value when the load is larger than 100%. , is a negative value when it is small. The configurations of other elements are shown in FIGS. 22 to 28. In the figure, A, A ₁ , A ₂ ... are inputs, B is output, P,
P ₁ , P ₂ ... are operational amplifiers, R ₁ , R ₂ ..., r ₁ , r ₂
... is a resistor, C is a capacitor, and D is a diode. FIG. 22 shows an inverting amplifier. Since B=-R ₂ /R ₁ A, when R ₁ =R ₂ , B=-A. FIG. 23 shows a normal rotation amplifier. Since B=R ₂ +R ₃ /R ₃・r ₂ /r ₁ +r ₂ A, R ₂ +R ₃ /R ₃・r ₂ /r ₁ +r ₂ can be expressed as

When [formula] is used,

〔Effect of the invention〕

As described above, in this invention, vector control is performed by separating the induction motor for driving an elevator car into a field current component and a torque current component, and at startup, the deviation between the torque current component command value and the torque current component is controlled. , the scale signal corresponding to the car load is added, and at startup and during control using the torque current component command value,
Since the gain of the torque current component feedback circuit is changed, the above gain at the time of starting the scale is set higher than the gain during running to improve the accuracy of the load detector and the responsiveness to changes in the load inside the car. In addition, by setting a high damping gain when starting the scale, it is possible to suppress overshoot of the scale torque and improve convergence, and to perform stable and highly accurate control at both startup and running. I can do it.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing one embodiment of an AC elevator speed control device according to the present invention, and FIG.
Figures 3 to 7 are circuit diagrams of the gate circuit in Figure 2, Figure 8 is a block circuit diagram of the base drive circuit in Figure 2, and Figure 9 is a block circuit diagram of the base drive circuit in Figure 8. The circuit diagram of the triangular wave generator, Fig. 10 is an operation explanatory diagram of Fig. 8, Fig. 11 is a block circuit diagram of the three-phase/two-phase coordinate converter of Fig. 1, and Fig. 12 is the two-phase diagram of Fig. 1. /A block circuit diagram of the three-phase coordinate converter, Figures 13 and 14 are block circuit diagrams of the compensation circuit in Figure 1, Figure 15 is a circuit diagram of the slip frequency calculation circuit in Figure 1, and Figure 16 is a block circuit diagram of the compensation circuit in Figure 1. Figure 1 is a block circuit diagram of the sin/cos converter, Figure 17 is a circuit diagram of the speed command circuit in Figure 1, Figure 18 is an operation explanatory diagram of Figure 17,
Figure 9 is a circuit diagram of the field command circuit in Figure 1, Figure 20 is a configuration diagram of the load detector and scale circuit part in Figure 1,
FIG. 21 is an input/output characteristic diagram of the scale circuit in FIG. 20, and FIGS. 22 to 31 are circuit diagrams of other elements.
The figure shows an inverting amplifier, Figure 23 shows a normal amplifier, and Figure 24 shows an inverting amplifier.
25 is a subtracter, FIG. 26 is an integrator, FIG. 27 is a delay/lead circuit, FIG. 28 is a lead/lag circuit, and FIGS. 29 to 31 are circuit diagrams of a comparator.
32 and 33 are partial circuit diagrams of FIG. 1 showing another embodiment of the invention. In the figure, 1 is a VVVF control device, 2 is a three-phase induction motor, 3 to 5 are DC current transformers, 6 is a three-phase/two coarse coordinate converter, 7 is a speed detector, 10 is a cage, and 12 is a load detector. 13 is a scale circuit, 14 is a speed command circuit,
15, 17 are subtracters, 19 is a field command circuit, 20
2 is a subtracter, 22 is a slip frequency calculation circuit, 23 is an adder, 24 is an integrator, 25 is a sin/cos converter, 2
7 is a damping circuit, 32 is a two-phase/three-phase coordinate converter, P ₁ to _{P 3} are operational amplifiers, R ₁ to _{R 13} are resistors, C ₁ ,
_C2 is a capacitor, and 111 is a starting relay contact. Note that the same reference numerals in the figures indicate the same parts.

Claims (1)

[Claims] 1 The field current component detected from the current of the car drive motor is fed back via the field current component feedback circuit, the deviation between this and the field current component command value is calculated and input to the converter, and the above The torque current component detected from the current is fed back via the torque current component feedback circuit, the deviation between this and the torque current component command value is calculated, and a scale signal corresponding to the load inside the car is sent back to the above torque when starting the car. The torque current component is added to the deviation between the current component command value and the torque current component and inputted to the converter, and the speed of the motor is controlled by the voltage command value generated by the converter. A speed control device for an AC elevator, comprising a gain setting circuit that is inserted into a feedback circuit and changes the gain of the torque current component feedback circuit when the car is started and when the car is controlled by the torque current component command value. .