JPH0287971A - Phase converter - Google Patents

Abstract

PURPOSE:To reduce the size and the weight of a load motor by providing an intermediate terminal for dividing the output voltage from the ternary winding of transformer unequally and making the voltage variation rate at the side having large number of turn higher than that at the side having small number of turn. CONSTITUTION:One intermediate terminal Z is provided in the ternary winding 14 of a transformer 10 such that the number of turn at U terminal side will be smaller than that at V terminal side, and the intermediate terminal Z is connected directly and permanently with the terminal of the auxiliary winding 16 of a phase converter 16. Voltage variation rate of the ternary winding is set such that epsilonu<epsilonv where epsilonu is the voltage variation rate of U-Z phase of the ternary winding and epsilonv is the voltage variation rate of V-Z phase of the ternary winding. The relation can be set, for example, by constituting the ternary winding with two independent windings and selecting the mutual spacial position or the spacial position with respect to the primary winding. Since the voltages of V-W phase and W-U phase are equalized through internal impedance drop of the ternary winding and the phase converter os the load current increases, output voltage of the phase converter 16 does not increase excessively.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a rotating electrical machine type phase number converter that converts single-phase alternating current to three-phase alternating current.

[Conventional technology]

In AC electric cars, in addition to the main motor for driving the electric car, there is also an air blower motor for cooling the main motor, and an electric motor for cooling oil for the transformer. IJ machine,
Several low-voltage auxiliary motors, such as a resistor blower motor, are used. However, since the overhead wire voltage is single-phase alternating current, in order to convert the above-mentioned motor into a three-phase induction motor that is easy to maintain, a phase number converter is required to convert from single phase to three phases.

As described in Japanese Unexamined Patent Publication No. 59-25582, conventional devices provide a plurality of intermediate terminals in the tertiary winding in order to reduce the negative phase voltage and the unbalance rate of the output voltage. The connection was changed.

FIG. 4 shows an example of the prior art.

In FIG. 4, 10 is a transformer, which has a primary winding 12 and a secondary winding 13 that receive power from a pantograph 11 that is in contact with an overhead wire.
It has an output winding of a tertiary winding 14. The secondary winding 13 is connected via a main rectifier 15 to a main DC motor (not shown) for driving the vehicle. The tertiary winding has two center taps (or taps) and feeds the phase converter 16.

The phase number converter 16 is started as a single-phase induction motor using a resistance split phase starting method. That is, it has a main winding 16a and an auxiliary winding 16b, a starting resistor 17 is inserted in series with the auxiliary winding 16b via a starting switch 18, and the main winding 16a
A rotating magnetic field is created by shifting the phase of the magnetic flux produced by the auxiliary winding 16b and the magnetic flux produced by the auxiliary winding 16b, and the starting rotational force is generated to start the motor. After the rotational speed increases, the starting resistor 17 is disconnected by the starting switch 18, and the load switch 19 is turned on to supply three-phase alternating current to the load group 20 such as three-phase induction motors. Since the phase number converter 16 outputs a three-phase AC voltage by a combination of two windings, the main winding 16a and the auxiliary winding 16b, the overhead line voltage, that is, the input voltage from the tertiary winding 14 of the voltage generator 10 fluctuation,
and due to load fluctuations.

The three-phase output voltage is not a balanced voltage, and the complaints fa! It becomes pressure. That is, as shown in the vector diagram of the output voltage of the phase number converter shown in FIG. 5, the voltage vector W during no-load generated by the auxiliary winding 16b of the phase number converter 16.

-Z is larger than the voltage vector WIZ in a balanced state (normally at rated load), and the voltage vector WIZ of the main winding 16a is
The phase difference of the V phase with respect to the voltage vector UV is also large. On the other hand, the voltage vector W2 of the auxiliary winding 16b created during overload
−Z is smaller than the voltage vector WIZ in the balanced state, and the phase difference between the UV phase of the main winding 16a and the voltage vector UV is also small. Therefore, transformer 1
A plurality of intermediate terminals are provided in the tertiary winding 14 of the auxiliary winding 14, and the connections of the intermediate terminals are changed in accordance with the output voltage of the auxiliary winding 16b, which varies with changes in the load current. FIG. 6 shows the voltage vector when the connection is changed.

W2-Z is before the change and W22' is after the change.

[Problem to be solved by the invention]

The above conventional technology does not take into consideration maintenance and installation space for the transformer output terminal, and there are problems with securing play space and maintainability.

An object of the present invention is to provide a phase number conversion device that is easy to install and easy to maintain.

(Means for solving problem 111) The above purpose is to provide one intermediate terminal that divides the output voltage of the tertiary winding of the transformer into equal parts, and to make the voltage fluctuation rate on the side with a large number of turns larger than the rate of voltage fluctuation on the side with a small number of turns. This is achieved by

[Effect]

The operation of the present invention will be explained with reference to the drawings.

FIG. 7 shows a vector diagram of each current and voltage of the phase number converter. In the figure, the subscript 0.1.2 indicates that 0 indicates no load, 1 indicates rated load, and 2 indicates overload. Output voltage V u v HV
v w ) V w u is shown only at rated load.

As shown in FIG. 7, the output current of the tertiary winding I uolI
Since the power factor of the load motor is 0.8 to 0.9 and the power factor of the phase converter is about 0.5, vo is always Iu.

>IvO. As shown in FIG. 8, this means that an increase in the load current reduces the output voltage of the auxiliary winding 16b, and at the same time reduces the phase difference with the voltage of the U-V phase.
-The phase difference seen from the apparent midpoint of the V phase is made smaller to increase the voltage unbalance rate. In FIG. 5, Z indicates the midpoint of the UV phase voltage, and 2' indicates the point moved due to the current difference.

Therefore, an intermediate terminal is provided so that the no-load voltage of the tertiary winding becomes vu□<V2v, and the voltage fluctuation rate on the v-Z side (multiple turns side) is adjusted to the voltage fluctuation rate on the U-Z side (decimal turns side). By increasing the voltage of the auxiliary winding of the phase number converter to V, the intermediate terminal voltage of the tertiary winding increases as the load current increases.
It operates so that it can be pulled towards the terminal side. As a result, the auxiliary winding output voltage moves on a perpendicular line passing through the midpoint of the tertiary winding output voltage, so the output voltage of the phase number converter becomes approximately V vw = V wu, and the voltage is unchanged. The equilibrium rate can be reduced.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a main circuit diagram showing an embodiment of the phase number conversion device of the present invention.

In FIG. 1, one intermediate terminal Z is provided in the tertiary winding 14 of the transformer 10 so that the number of turns on the U terminal side is smaller than the number of turns on the V terminal side. A permanent connection is made directly to the terminal of the winding 16b.

The voltage fluctuation rate of the tertiary winding is Make sure that εu<tv.

Here, εG Voltage fluctuation rate of U-Z phase of tertiary winding εV: Voltage fluctuation rate of V-Z phase of tertiary winding As a method to obtain this relationship, for example, the tertiary winding can be formed by two independent windings. configure,
This can be achieved by selecting their spatial positions with respect to each other or with the primary winding.

Voltage fluctuation rate ε. The optimal value of and tv is determined by the combination of the phase number converter and the load characteristics, but at least F1
If ε9, the purpose can be achieved.

Further, it is assumed that the voltage vector W-Z phase generated by the auxiliary winding of the phase number converter leads the voltage vector of the UV phase by 90 degrees (electrical angle) or more.

Hereinafter, the present invention will be explained in detail using the vectors shown in FIG.

In Figure 2, U-V is the voltage between the UV terminals shown in Figure 1, and W-Z is the output voltage of the auxiliary winding -6b of the phase converter shown in Figure 1. , Wo Z.

is for light load, Wi Zt is rated load, W2-22
indicates the case of overload.

As is clear from Fig. 2, as the load current increases,
The output voltage of the phase number converter 16 does not increase significantly because the three factors, the drop in the internal impedance of the tertiary winding and the drop in the internal impedance of the phase converter 16, make the voltages of the -W phase and W-U phase almost equal. There's nothing to do.

Figure 3 shows the above condition in terms of the relationship between the voltage unbalance rate and the load capacity, and (, l) shows an example of the prior art with two intermediate terminals as shown in Figure 4. b) shows the case of the present invention.

The above explanation deals with the case where the voltage fluctuation rates of the tertiary winding of the transformer are made unequal, but the same effect can be obtained by connecting the tertiary winding and the phase converter through an appropriate impedance. It will be done.

〔Effect of the invention〕

According to the present invention, unnecessary heat generation and torque reduction due to unbalanced voltage of the load motor can be reduced, and the load motor can be made smaller and lighter.

[Brief explanation of the drawing]

Figure 1 is a system diagram of an embodiment of the present invention, Figures 2 and 3 are characteristic diagrams of Figure 1, Figure 4 is a circuit diagram of a conventional phase number converter, and Figures 5 and 6 are Characteristic diagrams in Figure 4, Figures 7 and 8
The figure is a characteristic explanatory diagram. 10...Transformer, 14-...Tertiary winding, 16...Phase number converter, 16a...Main winding, 16b...Auxiliary winding. High School 1st Ward 2 - Concave 4th Hour Map 荊S Map W. Figure 6

Claims (1)

[Claims] 1. A rotary phase converter that includes a main winding and an auxiliary winding and converts a single-phase power source into a three-phase power source, and an intermediate unit that supplies power to the phase converter. In a phase conversion device comprising a transformer having a tertiary output winding provided with terminals, the intermediate terminals are provided at unequal division points of the tertiary output winding, and
A phase number conversion device characterized in that a voltage fluctuation rate on a side with a large number of turns of the winding is made larger than a rate of voltage fluctuation on a side with a small number of turns.