JPH072040B2 - Starting torque control device for motor generator - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a starting torque control device for a motor generator, and more particularly to an electric motor suitable for use in a motor generator in which a motor and a generator are connected by an electromagnetic coupling. The present invention relates to a starting torque control device for a generator.

[Background of the Invention]

Conventionally, the method shown in FIG. 3 is generally used for speed control of a motor generator. That is, the output of the generator (G) 3 coupled to the induction motor (IM) 1 by the electromagnetic coupling 2 is detected by the speed detector 4 as a voltage corresponding to the speed, and the speed control circuit 5 outputs the rated speed. Is compared with the output of the speed setting device 7 that outputs the voltage value corresponding to the above, the power amplifier 6 is controlled according to the deviation, and the coupling state of the electromagnetic coupling 2 is adjusted.

In the case of the motor generator, the speed setter 7 often starts the induction motor 1 in a state where the speed setter 7 is set to a value corresponding to the rated speed because the speed is controlled at a constant speed. In this case, since the deviation between the speed command value and the speed feedback value is large until the rotation speed of the generator 3 approaches the rated speed, the power amplifier 6
Outputs maximum output. Therefore, the electromagnetic coupling 2 is started in the maximum coupled state, and the transmission torque at this time has a large value exceeding the rated torque of the motor generator.

As shown in FIG. 4, the electromagnetic coupling 2 has a cantilever structure in which the magnetic pole 12 is directly connected to the motor-side shaft 8 and is supported by the bearing 10, and the drum 13 is also in the cantilever structure. , Transmits the rotation between the magnetic pole 12 and the drum 13. If these shafts do not have a structure that can withstand the drive torque,
The shaft may be damaged, or the eccentricity of the magnetic pole 12 or the drum 13 due to the gravity may further promote the eccentricity, which may cause an accident of contact between the magnetic pole 12 and the drum 13. In order to prevent these problems, it is necessary to have a structure that can sufficiently withstand the starting torque, resulting in an uneconomical design.

In order to solve these drawbacks, as a known example closest to the present invention, there is "speed control device for motor generator" shown in FIG.

In FIG. 5, the control system A at the time of start-up includes an integrator 16, a wide-range speed detector 14 engaged with the electromagnetic coupling 2, and a start-up speed connected to the integrator 16 and the wide-range speed detector 14. It is composed of a control circuit 15. The control system B in the vicinity of the rated speed includes a narrow range speed detector 17 engaged with the electromagnetic coupling 2 similarly to the wide range speed detector 14, a rated speed setter 18, these narrow range speed detector 17 and the rated speed. It is composed of a rated speed control circuit 18 connected to the speed setter 2B. Furthermore, control system A,
A low value priority circuit 19 for switching B is provided.

The operation of the above configuration will be described. First, the control system A
Thus, the speed command is increased from zero to the rated value in proportion to time by the integrator 16, the difference between the command value and the speed feedback is reduced, the starting input current of the induction motor 1 is suppressed, and the rotation of the generator 3 is reduced. When the speed reaches the vicinity of the rated value, the control system B is switched to perform the rated speed control. This prior art controls the rotational speed of the generator by additional value when the motor generator is started.Besides that the starting torque is not managed, the additional value control causes a speed deviation, and the setting of the integrator 16 is extremely difficult. It has the drawback of being difficult.

[Object of the Invention]

An object of the present invention is to provide a starting torque control device for a motor generator, which makes the starting torque constant and enables economical design of the shaft of the electromagnetic coupling.

[Outline of Invention]

The present invention detects the starting torque from the rotation speed of the generator at the time of startup, and performs constant value control of this starting torque to the allowable transmission torque of the motor side shaft or the generator side shaft so that the rotation speed of the generator is close to the rated speed. When the speed is reached, it is automatically switched to the constant value speed control.

Example of Invention

An embodiment of the present invention will be described below with reference to FIGS. Note that the same reference numerals are used for the same elements as those in FIG. 5, and thus redundant description will be omitted. Fig. 1 shows control system A,
It is composed of a control system B, a switching circuit 22 and a power amplifier circuit 6. The control system A manages the torque at the time of startup, and the control system B is a circuit that controls the rotation speed of the generator 3 to a rated value by a constant value. Switching from the startup control to the constant value control is automatically performed by the switching circuit 22. To be done.

The switching circuit 22 is composed of a comparison circuit, and constantly monitors the output of the wide-range speed detector 14 and sets it so that the rotation speed of the motor generator 3 operates at one predetermined speed near the rated value. A signal for operating the control system A is output at the rotational speed until reaching the predetermined speed, and a signal for operating the control system B is output after reaching the predetermined speed.

Immediately after starting, the wide range speed detector 14 outputs a voltage proportional to the rotation speed of the generator 3. If this voltage is V _W , V _W = K1w (1) K1: constant w: rotational speed This V _W becomes an input to the starting torque control circuit 21. The starting torque control circuit 21 is composed of a circuit as shown in FIG. The starting torque control circuit 21 includes a coupling capacitor C1 and an operational amplifier.
OP1, return resistor R1, resistor R2 connected to the output terminal of the operational amplifier OP1, operational amplifier OP2 connected to the resistor R2, OP2
Is composed of a resistor R3 for inputting Vτ _P and a capacitor C2 connected between the input and output of the operational amplifier OP2.

In the above configuration, the output Vτ of the operational amplifier OP1 is Substituting equation (1), Generally, when torque τ is applied to a rotating body having an inertia moment J, the relationship with the rotation speed w is Becomes

Here, by comparing equations (3) and (4) and determining K1, C1, R1 as J = K1, C1, R1, the starting torque of the motor generator 3 can be detected from the output of the operational amplifier OP1. it can.

The set value Vtau _P starting torque Vtau the torque setter 20 compares the arithmetic unit OP2, integrates the deviation is inputted to the power amplifier 6.

In this way, the starting torque of the motor generator 3 is the set value Vτ _P
Fixed value control.

The rotation speed of the motor generator 3 increases with a constant starting torque. At the operating point of the switching circuit 22 near the rated rotation speed, the control system A is disconnected and the control system B is connected to the power amplifier 6. At this time, since the rotation speed of the generator 3 has already risen close to the rated value, a large starting torque is not required, and the signal detected by the narrow range speed detector 17 is the rated speed control circuit 18
The power amplifier 6 is compared and amplified with the command value of the speed setter 7 at
Is operated to control the frequency of the motor generator 3 against a disturbance such as a load change.

Generally, a motor generator is required to have high accuracy as a frequency settling accuracy, so that the narrow-range speed detector 17 is required to have high accuracy, but the wide-range speed detector 14 has only such a high accuracy as starting torque control. You don't have to.

〔The invention's effect〕

According to the present invention, since the starting torque is controlled to be constant, if the starting torque is set to the maximum allowable torque during rated operation,
The shaft of the electromagnetic coupling can be economically designed and the weight can be reduced.

[Brief description of drawings]

1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a detailed circuit diagram of the starting torque control circuit 21 in FIG. 1, FIG. 3 is a block diagram showing a conventional speed control circuit, and FIG. Is a schematic configuration diagram showing an example of an electromagnetic coupling, and FIG. 5 is a circuit diagram showing a conventional speed control circuit. 1 ... Induction motor, 2 ... Electromagnetic coupling, 3 ... Generator, 6
…… Power amplifier, 7 …… Speed setter, 8 …… Motor side shaft, 9 …… Generator side shaft, 10 …… Motor side bearing, 11 …… Generator side bearing, 12 …… Pole, 13 …… Drum, 14 ... Wide area speed detector, 17 ... Narrow area speed detector, 18 ... Rated speed control circuit, 20 ... Starting torque setting device, 21 ... Starting torque control circuit, 22 ... Switching circuit, A …… Control system, B …… Control system,
C1 to C2 …… Condenser, R1 to R3 …… Resistor, OP1 to OP2
…… Operational amplifier.

Claims (1)

[Claims] 1. A starting torque control device for a motor generator, wherein a rotating shaft of a generator is connected to an output shaft of an electric motor via an electromagnetic coupling, and a coupling state of the electromagnetic coupling is controlled according to a rotation speed of the rotating shaft. , A speed detecting means for detecting a rotating speed of the rotating shaft, and a starting torque of the generator corresponding to the rotating speed detected by the speed detecting means, and the starting torque is set to a set value equal to or less than an allowable transmission torque. Starting torque control means for obtaining a first control amount, rated speed control means for obtaining a second control amount for constant value control of the rotation speed detected by the speed detection means to a rated speed, and rotation speed detected by the speed detection means Until the rotational speed detected by the speed detecting means reaches the predetermined speed by controlling the coupling state of the electromagnetic coupling with the first controlled variable output from the starting torque control means. Motor generator starting torque control device, characterized in that it comprises a switching means for controlling the bonding state of the electromagnetic coupling with the second control amount output from the rated speed control means.