JPS6066700A - Controlling method of motor generator - Google Patents

Abstract

PURPOSE:To rapidly attenuate a counterelectromotive force by applying a reverse excitation to a self-shunt field with the counterelectromotive force of a motor generated by the inertial rotation as a power source. CONSTITUTION:When a pantograph 2 is raised and a motor generator operating start command is outputted by a driver, a breaker 4 is closed to flow current from a power source 1 through the pantograph 2, a disconnecting switch 3 to an armature 56, a series field 9 and a shunt field 11 to start rotating of armatures 5, 6, and necessary power is generated from a generator coupled directly to the armatures. A field current of if0 is flowed through the field 11 in the normal operation state. When the switch 3 is shifted to the ground side by an operation stop command, field changeover switches 17, 18 are closed in cooperation therewith, and a current of the direction designated by a field current if1 is flowed to the shunt field 11 with the counterelectromotive force as a power source, and the counterelectromotive force is rapidly attenuated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a control method for a motor generator, and particularly to a control method suitable for preventing electric shock due to residual voltage of a motor.

[Background of the invention]

2. Description of the Related Art Motor generators (hereinafter abbreviated as MA) are often used as auxiliary power supplies for trains and the like. MA circuit.

In particular, large-capacity devices have a configuration as shown in FIG. In the figure, 1 is a power supply, 2 is a pantograph, 3 is a disconnector, 4 is a circuit breaker, 5 and 6 are armatures, 7 is a compensation winding,
8 is a commutating pole, 9 is a series winding field, lO is a field resistance, 11 is a shunt winding field, 12 is a backflow blocking diode, and 13 is a generator.

Now, when the pantograph 2 goes up and the driver issues a command to start MA operation, the circuit breaker 4 closes and the power supply 1 supplies the armatures 5, 6, series field 9, and shunt field through the pantograph 2 and disconnector 3. When a current flows through the magnet 11, the armatures 5 and 6 start rotating. When the armature 5.6 rotates, the generator directly connected to it also rotates and can generate the necessary power.

At this time, the armatures 5 and 6 generate a back electromotive force EM1t to prevent current exceeding that necessary to rotate the load from flowing into the armature.
Rotate to produce EM2. This back electromotive force EM□+E
In a steady state of operation, M2 is generated to a value almost equal to the power supply voltage.

Next, M A! Assume that a rotation stop command is issued. When the circuit breaker 2 opens +lJj L, the power supply voltage is no longer applied to the motor. But electricity! I! Due to the inertia of the II machine, after a stop command is given, it usually continues to rotate for several minutes. Due to the rotation, a field current i flows using the back electromotive force EM2 as a power source, and this causes the back electromotive force EM2 to flow. Power continues to be generated, although it is attenuated.

Here, let us consider opening and opening of the MA by operating a disconnector by maintenance personnel. h4 A failure occurs and the disconnector is opened to open MA.

At this time, electricity! Assuming that the IIJ machine continues to rotate due to inertia, even if the disconnector is opened, it will still generate a back electromotive force for more than ten minutes as described above. If you accidentally touch the circuit, you may get an electric shock and die. In particular, the power supply voltage is 300
If the voltage is as high as 0 V, the back electromotive force is almost the same, so the danger is great.

The following two methods can be considered to solve this problem.

First, as shown in FIG. 2, there is a method in which a shunt field short-circuiting switch 14 is provided. Since the ampere turns of a shunt field are sufficiently larger than those of a series field, the idea is to eliminate the shunt field.

The field current I N due to the back electromotive force EM2 bypasses the shunt field, but since the shunt field circuit has a time constant of, for example, 0.3 seconds, the initial field current i, . Even if the shunt field current becomes OA, a back electromotive force remains as a residual voltage due to the no-load saturation characteristics of the motor. For example, current voltage 3000 V, ll0
In the case of KVA MA, the residual voltage is as high as 500V. It can be said that there is still a sufficient risk of electric shock.

The second is the armature short switch 1, as shown in Figure 3.
This is a method of providing 6. The armatures 5 and 6 generating back electromotive force are connected to the armature short-circuit switch 16 via the limiting resistor 15.
This method eliminates the generated 1"lX/jE by short-circuiting. Although this method can completely eliminate the generated voltage, it requires housing and insulation of the armature short-circuit switch. This is because a voltage generation source equal to the power supply voltage is short-circuited with a resistor.

In this case, the shunt field current i is caused by the back electromotive force EM2.

It also leaks, so it takes time for it to decay. Therefore, this cannot be considered a practically good method.

[Purpose of the invention]

An object of the present invention is to provide a control method that quickly attenuates the back electromotive force generated by a motor rotating due to inertia.

[Summary of the invention]

The key point of the present invention is to use the back electromotive force generated by the motor as it rotates due to inertia as a power source, and apply reverse excitation to its own shunt field to eliminate the field magnetic flux and quickly eliminate the back electromotive force. The purpose is to attenuate the

[Embodiments of the invention]

An embodiment of the present invention will be described based on the drawings.

FIG. 4 is a MAA road diagram showing one embodiment of the present invention.

Comparing with Figure 1, the field resistance 1o is 15'A and 15'A.
It is divided into two parts I3 and is further provided with field changeover switches 17 and 18 that operate in conjunction with the disconnector 3.

In the steady state of operation, the shunt field 11 has i,. A field 6jXi current flows in the direction shown by JL. Now, switch the disconnector 3 to the ground side. That is, when the MA is opened, the field changeover switch 1.7.18 is turned on in conjunction with the opening operation.

In this case, the back electromotive force is used as a power source, and a current in the direction indicated by the field current i r+ is caused to flow through the shunt field 11.

FIG. 5 shows an equivalent circuit at this time. Here the power supply voltage is 30
Considering the MA of 00V and full OKVA, the back electromotive force will be +500V in one armature, or EM2. The impedance of the shunt field 11 is 200H1, internal resistance 609Ω, and field resistance 15A.

The impedance of 15B is 200Ω. Further, the initial field current i to is 1.5 Δ.

FIG. 6 shows the results of simulating the time course of EM2 and 1r using these circuit constants. Field current if is O
Even in state A, one armature has a residual voltage of 5
a o v, tli[Ie is twice too v
remains. Furthermore, by reverse excitation, the field current 1. . has the opposite polarity. Thus, it can be seen that the back electromotive force EM2 is completely attenuated in 2 to 3 seconds after the field changeover switch is turned on.

In this way, the counter electromotive force, which conventionally required more than ten minutes to decay, can be reduced to just a few seconds.

〔Effect of the invention〕

According to the present invention, the back electromotive force generated due to inertia can be quickly attenuated, so that maintenance personnel and the like can be prevented from receiving an electric shock.

[Brief explanation of drawings]

Figure 1 is a conventional MA circuit diagram, Figures 2 and 3 are MA circuit diagrams as an improvement plan, and Figure 4 is an MA circuit diagram of an embodiment of the present invention.
Δ circuit diagram, FIG. 5 is an equivalent circuit diagram when the shunt field is reversely excited, and FIG. 6 is a characteristic diagram of the simulation result. jl shunt field, 5, 6... armature, l 5 A,
1513$ 5 Mouth Kayotsu

Claims (1)

[Claims] 1. A power switch that opens and closes a power supply and a main circuit, an armature connected in series with the power switch, a series field connected in series with the armature, and the armature. In the control method of a motor generator comprising a shunt field connected in reverse series from
i source, and the shunt field is reconnected by a reconnection switch so that a current of opposite polarity to the field current flowing up to that point flows in the shunt field. Control method. 2. A method for controlling a motor generator according to claim 1, characterized in that the power supply switch and the switching switch are linked.