CN101777867A - Voltage compensation device for rare-earth permanent magnet motor - Google Patents

Abstract

The invention provides a voltage compensation device for a rare earth permanent magnet motor, comprising: a double-winding transformer; the double-winding transformer includes a primary winding and a secondary winding; the primary winding is connected to a power supply; the secondary winding has at least One tap; when the induction potential of the rare earth permanent magnet motor is lower than the power supply voltage, the same-named end of the secondary winding is connected to the power supply, and the opposite-named end of the secondary winding or a tap is connected to the first stator winding of the rare earth permanent magnet motor. end, the end of the stator winding of the rare earth permanent magnet motor is connected to the neutral point of the motor. The voltage compensation device provided by the invention can match the voltage on the stator winding with the induced potential, thereby improving the power factor of the rare earth permanent magnet motor.

Description

A voltage compensation device for rare earth permanent magnet motor

technical field

The invention relates to the technical field of rare earth permanent magnet motors, in particular to a voltage compensation device for rare earth permanent magnet motors.

Background technique

The rare earth permanent magnet motor has a high power factor when its induced potential is equal to the power supply voltage. However, when the power supply voltage deviates from the induced potential, the power factor will drop significantly due to the mismatch between the power supply voltage and the induced potential.

For example, when the load is 20% of the rated power and the power supply voltage is equal to the rated voltage, the power factor of the rare earth permanent magnet motor can reach more than 0.97. But when the power supply voltage deviates from the rated voltage by ±5%, the power factor of the rare earth permanent magnet motor will drop to 0.5-0.7.

In oil fields, the length of power supply lines can generally reach about 10 kilometers, and some even reach 20 to 30 kilometers. The longer the power supply line, the greater the voltage drop across the power supply line. A large number of actual measurements show that the power supply voltage at the head end of the power supply line often reaches 400V-420V, while the power supply voltage at the end of the power supply line will drop to 350V-360V. It can be seen that when the power supply line is long, there is a large difference between the voltage at the head end and the voltage at the end. In this way, the power supply voltage of the rare earth permanent magnet motor working at the end of the power supply line will be lower than its rated voltage.

Contents of the invention

The technical problem to be solved by the present invention is to provide a voltage compensation device for a rare earth permanent magnet motor, which can match the induced potential of the rare earth permanent magnet motor with the power supply voltage.

The invention provides a voltage compensation device for a rare earth permanent magnet motor, comprising: a double-winding transformer;

The double-winding transformer includes a primary winding and a secondary winding; the primary winding is connected to a power supply; the secondary winding has at least one tap;

When the induced potential of the rare-earth permanent magnet motor is lower than the power supply voltage, the same-named end of the secondary winding is connected to the power supply, and the different-named end or a tap of the secondary winding is connected to the first end of the stator winding of the rare-earth permanent magnet motor. The end of the stator winding of the rare earth permanent magnet motor is connected to the neutral point of the motor.

Preferably, the primary winding is connected to a power supply, specifically:

The first end of the primary winding is connected to the power supply, and the tail end of the primary winding has two taps, which are the first tap and the second tap from the tail end to the first end;

The tail end, the first tap or the second tap is connected to the neutral point of the transformer.

Preferably,

The opposite end of the secondary winding or a tap is connected to the head end of the stator winding of the rare earth permanent magnet motor, specifically: the opposite end of the secondary winding is connected to the head end of the stator winding of the rare earth permanent magnet motor, and the tap floating;

or,

One tap of the secondary winding is connected to the head end of the electronic winding of the rare earth permanent magnet motor, and the opposite end of the secondary winding is suspended.

The present invention also provides a voltage compensation device for a rare-earth permanent magnet motor, including: a double-winding transformer;

The double-winding transformer includes a primary winding and a secondary winding, the primary winding is connected to a power supply; the secondary winding has at least one tap;

When the induction potential of the rare earth permanent magnet motor is greater than the power supply voltage, the opposite end of the secondary winding is connected to the power supply, and the same end or a tap of the secondary winding is connected to the head end of the stator winding of the rare earth permanent magnet motor, so The end of the stator winding of the rare earth permanent magnet motor is connected to the neutral point of the motor.

Preferably, the primary winding is connected to a power supply voltage, specifically:

The first end of the primary winding is connected to the power supply, and the tail end of the primary winding has two taps, which are the first tap and the second tap from the tail end to the first end;

The tail end, the first tap or the second tap is connected to the neutral point of the transformer.

Preferably,

The end of the same name of the secondary winding or a tap is connected to the head end of the stator winding of the rare earth permanent magnet motor, specifically: the end of the same name of the secondary winding is connected to the head end of the stator winding of the rare earth permanent magnet motor, and the second end The tap of the winding is suspended;

or,

One tap of the secondary winding is connected to the first end of the stator winding of the rare earth permanent magnet motor, and the same-named end of the secondary winding is suspended.

Compared with the prior art, the present invention has the following advantages:

The voltage compensation device of the rare earth permanent magnet motor can compensate the voltage of the rare earth permanent magnet motor through the secondary winding of the double winding transformer connected in series with the electronic winding of the rare earth permanent magnet motor. When the power supply voltage is higher than the induction potential of the rare-earth permanent magnet motor, the secondary winding of the double-winding transformer and the stator winding are connected in series to the power supply voltage; when the power supply voltage is lower than the induction potential of the rare-earth permanent magnet motor, the double-winding transformer’s The secondary winding and the stator winding are connected in reverse series to the power supply voltage, so that the voltage on the stator winding can match the induced potential, thereby improving the power factor of the rare earth permanent magnet motor.

Description of drawings

Fig. 1 is the structural diagram of the dual-winding transformer in the voltage compensating device of the rare earth permanent magnet motor provided by the present invention;

Fig. 2 is a schematic diagram of Embodiment 1 of the voltage compensation device provided by the present invention;

Fig. 3 is a schematic diagram of Embodiment 2 of the voltage compensation device provided by the present invention;

Fig. 4 is another schematic diagram of Embodiment 2 provided by the present invention;

Fig. 5 is a schematic diagram of Embodiment 3 of the voltage compensation device provided by the present invention;

Fig. 6 is a schematic diagram of Embodiment 4 of the voltage compensation device provided by the present invention;

Fig. 7 is another schematic diagram of Embodiment 4 provided by the present invention;

Fig. 8 is a schematic diagram of Embodiment 5 of the voltage compensation device provided by the present invention.

Detailed ways

In order to make the above objects, features and advantages of the present invention more comprehensible, specific implementations of the present invention will be described in detail below in conjunction with the accompanying drawings.

Let's first introduce the two-winding transformer.

Referring to FIG. 1 , this figure is a structural diagram of a double-winding transformer in a voltage compensation device for a rare earth permanent magnet motor provided by the present invention.

The double-winding transformer is a three-phase transformer, which is referred to as A-phase, B-phase and C-phase for convenience of description.

Each phase of the double-winding transformer includes a primary winding and a secondary winding. Since the three-phase stator winding of the rare earth permanent magnet motor is symmetrical, the connection between each phase of the three-phase transformer and each phase of the stator winding is also symmetrical.

As shown in Figure 1, the A-phase of the three-phase transformer includes the A-phase primary winding and the A-phase secondary winding. Among them, the terminal with the same name of the primary winding of phase A is A4, the terminal of the secondary winding of phase A with the same name is A1, the terminal of the opposite name of the primary winding of phase A is X1, and the terminal of the secondary winding of phase A with the same name is A3. The A-phase secondary winding has a center tap A2.

The B-phase of the three-phase transformer includes the B-phase primary winding and the B-phase secondary winding. Among them, the terminal with the same name of the B-phase primary winding is B4, the terminal with the same name of the B-phase secondary winding is B1, the terminal with the same name of the B-phase primary winding is Y1, and the terminal with the same name of the B-phase secondary winding is B3. The B-phase secondary winding has a center tap B2.

The C-phase of the three-phase transformer includes a C-phase primary winding and a C-phase secondary winding. Among them, the end with the same name of the C-phase primary winding is C4, the end of the C-phase secondary winding with the same name is C1, the end of the C-phase primary winding with the same name is Z1, and the end of the C-phase secondary winding with the same name is C3. The C-phase secondary winding has a center tap C2.

It should be noted that the secondary winding of the three-phase transformer in Figure 1 has only one tap at the center, which is called the center tap. It can be understood that, in addition to the center tap, the secondary winding may also have multiple taps. For the convenience of description, in all the following embodiments, the secondary winding has a center tap as an example. The connection relationship when there are other taps is the same as The center taps are the same and will not be repeated here.

In all the following embodiments, it is assumed that the rated value of the power supply voltage, the rated voltage of the primary side of the double-winding transformer, and the rated voltage of the rare earth permanent magnet motor are all 380V, and the rated voltage of the secondary side of the double-winding transformer is 8% of the rated value of the power supply voltage. It should be noted that the connection of the three-phase stator windings is a star connection, and the ends are connected together to become the neutral point of the motor.

Referring to FIG. 2 , this figure is a schematic diagram of Embodiment 1 of the voltage compensation device provided by the present invention.

The compensation device provided in this embodiment connects the entire secondary winding of the double-winding transformer in forward series with the stator winding, and is suitable for the power supply voltage being greater than the induced potential E of the motor, and the power supply voltage is within the range of (1.08±0.02)E.

The same-named terminal A4 of the A-phase primary winding is connected to the A-phase of the power supply, and the different-named terminal X1 of the A-phase primary winding is connected to the neutral point of the transformer.

The same-named end A1 of the A-phase secondary winding is connected to the A-phase of the power supply, and the different-named end A3 of the A-phase secondary winding is connected to the first end of the U-phase stator winding of the rare earth permanent magnet motor, and the end of the U-phase stator winding is connected to the neutral point of the transformer. .

It should be noted that in this embodiment, the opposite end A3 of the A-phase secondary winding is connected to the head end of the U-phase stator winding, and the center tap A2 of the A-phase secondary winding is suspended.

The same-named terminal B4 of the B-phase primary winding is connected to the B-phase of the power supply, and the different-named terminal Y1 of the B-phase primary winding is connected to the neutral point of the transformer.

The same-named end B1 of the B-phase secondary winding is connected to the B-phase of the power supply, and the different-named end B3 of the B-phase secondary winding is connected to the first end of the V-phase stator winding of the rare earth permanent magnet motor, and the end of the V-phase stator winding is connected to the neutral point of the motor .

It should be noted that in this embodiment, the opposite terminal B3 of the B-phase secondary winding is connected to the head end of the V-phase stator winding, and the center tap B2 of the secondary winding is suspended.

The same-named terminal C4 of the C-phase primary winding is connected to the C-phase of the power supply, and the different-named terminal Z1 of the C-phase primary winding is connected to the neutral point of the transformer.

The same-named terminal C1 of the C-phase secondary winding is connected to the C-phase of the power supply, the different-named terminal C3 of the C-phase secondary winding is connected to the first end of the W-phase stator winding of the rare earth permanent magnet motor, and the end of the W-phase stator winding is connected to the neutral point of the motor.

It should be noted that in this embodiment, the opposite terminal C3 of the C-phase secondary winding is connected to the head end of the W-phase stator winding, and the center tap C2 of the secondary winding is suspended.

Refer to FIG. 3 , which is a schematic diagram of Embodiment 2 of the voltage compensation device provided by the present invention.

The compensation device provided in this embodiment is to connect half of the secondary winding of the double-winding transformer and the stator winding in forward series, which is suitable for the power supply voltage to be greater than the induced potential E of the motor, and the power supply voltage is within the range of (1.04±0.02)E .

As shown in Figure 3, the same-named terminal A4 of the A-phase primary winding is connected to the power supply voltage A, and the different-named terminal X1 of the A-phase primary winding is connected to the neutral point of the transformer.

The terminal with the same name of the A-phase secondary winding is connected to the A-phase of the power supply, the center tap A2 of the A-phase secondary winding is connected to the first end of the U-phase stator winding, and the end of the U-phase stator winding is connected to the neutral point of the motor.

It should be noted that in this embodiment, the opposite terminal A3 of the A-phase secondary winding is suspended.

The same-named terminal B4 of the B-phase primary winding is connected to the B-phase of the power supply, and the different-named terminal Y1 of the B-phase primary winding is connected to the neutral point of the transformer.

The same-named terminal B1 of the B-phase secondary winding is connected to the B-phase of the power supply, the center tap B2 of the B-phase secondary winding is connected to the first end of the V-phase stator winding, and the end of the V-phase stator winding is connected to the neutral point of the motor.

It should be noted that in this embodiment, the opposite terminal B3 of the B-phase secondary winding is suspended.

The same-named terminal C4 of the C-phase primary winding is connected to the C-phase of the power supply, and the different-named terminal Z1 of the C-phase primary winding is connected to the neutral point of the transformer.

The terminal with the same name of the C-phase secondary winding is connected to the C-phase of the power supply, the center tap C2 of the C-phase secondary winding is connected to the first end of the W-phase stator winding, and the end of the W-phase stator winding is connected to the neutral point of the motor.

It should be noted that in this embodiment, the opposite terminal C3 of the C-phase secondary winding is suspended.

There is another situation where half of the secondary winding of a double-winding transformer is connected in series with the stator winding in forward direction, as shown in Figure 4, taking phase A as an example for illustration, the center tap A2 of the secondary winding of phase A is connected to the power supply voltage A, and the secondary The opposite end A3 of the winding is connected to the first end of the U-phase stator winding, and the end of the U-phase stator winding is connected to the neutral point of the motor. It should be noted that, in this case, the terminal A1 with the same name of the secondary winding of phase A is suspended.

The voltage compensating device for the rare earth permanent magnet motor provided in the first and second embodiments can compensate the voltage of the rare earth permanent magnet motor through the secondary winding of the double-winding transformer connected in series with the electronic winding of the rare earth permanent magnet motor. When the power supply voltage is higher than the induction potential of the rare-earth permanent magnet motor, the secondary winding of the double-winding transformer is connected to the power supply voltage in forward series with the stator winding; The power factor of a magnetic motor.

Referring to FIG. 5 , this figure is a schematic diagram of Embodiment 3 of the voltage compensation device provided by the present invention.

The compensation device provided by this embodiment connects the entire secondary winding of the double-winding transformer in reverse series with the stator winding, and is suitable for the power supply voltage being greater than the induced potential E of the motor, and the power supply voltage is within the range of (0.92±0.02)E.

The same-named terminal A4 of the A-phase primary winding is connected to the A-phase of the power supply, and the different-named terminal X1 of the A-phase primary winding is connected to the neutral point of the transformer.

The same-named end A1 of the A-phase secondary winding is connected to the first end of the U-phase stator winding of the rare earth permanent magnet motor, the different-named end A3 of the A-phase secondary winding is connected to the A-phase of the power supply, and the end of the U-phase stator winding is connected to the neutral point of the motor.

It should be noted that, in this embodiment, the center tap A2 of the A-phase secondary winding is suspended.

The same-named terminal B4 of the B-phase primary winding is connected to the B-phase of the power supply, and the different-named terminal Y1 of the B-phase primary winding is connected to the neutral point of the transformer.

The same-named end B1 of the B-phase secondary winding is connected to the first end of the V-phase stator winding of the rare earth permanent magnet motor, the different-named end B3 of the B-phase secondary winding is connected to the B-phase of the power supply, and the end of the V-phase stator winding is connected to the neutral point of the motor.

It should be noted that, in this embodiment, the center tap B2 of the B-phase secondary winding is suspended.

The same-named terminal C4 of the C-phase primary winding is connected to the C-phase of the power supply, and the different-named terminal Z1 of the C-phase primary winding is connected to the neutral point of the transformer.

The same-named terminal C1 of the C-phase secondary winding is connected to the first end of the W-phase stator winding of the rare earth permanent magnet motor, the different-named terminal C3 of the C-phase secondary winding is connected to the C-phase of the power supply, and the end of the W-phase stator winding is connected to the neutral point of the motor.

It should be noted that, in this embodiment, the center tap C2 of the C-phase secondary winding is suspended.

Refer to FIG. 6 , which is a schematic diagram of Embodiment 4 of the voltage compensation device provided by the present invention.

The compensation device provided in this embodiment is to connect half of the secondary winding of the double-winding transformer in reverse series with the stator winding, which is suitable for the power supply voltage to be greater than the induced potential E of the motor, and the power supply voltage is within the range of (0.96±0.02)E .

The same-named terminal A4 of the A-phase primary winding is connected to the A-phase of the power supply, and the different-named terminal X1 of the A-phase primary winding is connected to the neutral point of the transformer. The same-named end A1 of the A-phase secondary winding is connected to the first end of the U-phase stator winding, and the center tap A2 of the A-phase secondary winding is connected to the A-phase of the power supply. The end of the U-phase stator winding is connected to the neutral point of the motor.

The same-named terminal B4 of the B-phase primary winding is connected to the B-phase of the power supply, and the different-named terminal Y1 of the B-phase primary winding is connected to the neutral point of the transformer. The same-named end B1 of the B-phase secondary winding is connected to the first end of the U-phase stator winding, and the center tap B2 of the B-phase secondary winding is connected to the B-phase of the power supply. The end of the U-phase stator winding is connected to the neutral point of the motor.

The same-named terminal C4 of the C-phase primary winding is connected to the C-phase of the power supply, and the different-named terminal Z1 of the C-phase primary winding is connected to the neutral point of the transformer. The same-named end C1 of the C-phase secondary winding is connected to the first end of the U-phase stator winding, and the center tap C2 of the C-phase secondary winding is connected to the C-phase of the power supply. The end of the U-phase stator winding is connected to the neutral point of the motor.

It should be noted that, in this embodiment, half of the secondary winding of the double-winding transformer is connected in reverse with the stator winding, as shown in Fig. 7, taking phase A as an example for illustration, the terminal A4 with the same name of the primary winding of phase A Connect the A phase of the power supply, and connect the neutral point of the transformer with the opposite terminal X1 of the primary winding of the A phase. The center tap A2 of the A-phase secondary winding is connected to the first end of the U-phase stator winding, the opposite terminal A3 of the A-phase secondary winding is connected to the A phase of the power supply, and the same terminal A1 is suspended. The end of the U-phase stator winding is connected to the neutral point of the motor.

The voltage compensating device for the rare earth permanent magnet motor provided in Embodiment 3 and Embodiment 4 can compensate the voltage of the rare earth permanent magnet motor by connecting the secondary winding of the double-winding transformer in series with the electronic winding of the rare earth permanent magnet motor. When the power supply voltage is lower than the induction potential of the rare earth permanent magnet motor, the secondary winding of the double-winding transformer is connected to the power supply voltage in reverse series with the stator winding, so that the voltage on the stator winding can match the induction potential, thereby improving the rare earth permanent magnet motor. The power factor of a magnetic motor.

Refer to FIG. 8 , which is a schematic diagram of Embodiment 5 of the voltage compensation device provided by the present invention.

The voltage compensation device provided in this embodiment can not only adjust the voltage applied to the stator winding by changing the connection between the secondary side of the double-winding transformer and the stator winding, but also change the connection between the primary winding and the neutral point of the double-winding transformer. connection for finer regulation of the voltage applied to the stator windings.

As shown in Figure 8, the head end of the primary winding is connected to the power supply voltage, and the tail end of the primary winding has two taps, which are the first tap and the second tap in turn from the tail end to the head end; One or two taps are connected to neutral.

The first tap at the end of the A-phase primary winding is X2 and the second tap is X3; the first tap at the end of the B-phase primary winding is Y2 and the second tap is Y3; the first tap at the end of the C-phase primary winding is Z2 , The second tap is Z3.

Changing the connection mode of the tail end of the primary winding and the connection between the tap and the neutral point can be applied to different power supply voltages. The basic principle is: when the power supply voltage is equal to the rated value of the primary voltage, the first tap connection of each primary winding Neutral point; when the power supply voltage is higher than the rated value of the primary voltage, the opposite end of each primary winding is connected to the neutral point; when the power supply voltage is lower than the rated value of the primary voltage, the second tap of each primary winding is connected sexual point.

Specifically, the ratio of the number of turns between the two taps to the number of turns of the entire primary winding can be selected as 5%. For example, when the power supply voltage is higher than 102.5% of the primary voltage rating, the opposite ends of each primary winding are connected to the neutral point. When the power supply voltage is lower than 97.5% of the rated value of the primary side voltage, the second tap of each primary side winding is connected to the neutral point.

The above descriptions are only preferred embodiments of the present invention, and do not limit the present invention in any form. Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person familiar with the art, without departing from the scope of the technical solution of the present invention, can use the methods and technical content disclosed above to make many possible changes and modifications to the technical solution of the present invention, or modify it into an equivalent of equivalent change Example. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention, which do not deviate from the technical solution of the present invention, still fall within the protection scope of the technical solution of the present invention.

Claims (6)

1. A voltage compensation device for a rare-earth permanent magnet motor, characterized in that it comprises: a double-winding transformer; The double-winding transformer includes a primary winding and a secondary winding; the primary winding is connected to a power supply; the secondary winding has at least one tap; When the induced potential of the rare-earth permanent magnet motor is lower than the power supply voltage, the same-named end of the secondary winding is connected to the power supply, and the different-named end or a tap of the secondary winding is connected to the first end of the stator winding of the rare-earth permanent magnet motor. The end of the stator winding of the rare earth permanent magnet motor is connected to the neutral point of the motor. 2. The voltage compensation device of the rare earth permanent magnet motor according to claim 1, wherein the primary winding is connected to a power supply, specifically: The first end of the primary winding is connected to the power supply, and the tail end of the primary winding has two taps, which are the first tap and the second tap from the tail end to the first end; The tail end, the first tap or the second tap is connected to the neutral point of the transformer. 3. The voltage compensation device of the rare earth permanent magnet motor according to claim 1, characterized in that, The opposite end of the secondary winding or a tap is connected to the head end of the stator winding of the rare earth permanent magnet motor, specifically: the opposite end of the secondary winding is connected to the head end of the stator winding of the rare earth permanent magnet motor, and the tap floating; or, One tap of the secondary winding is connected to the head end of the electronic winding of the rare earth permanent magnet motor, and the opposite end of the secondary winding is suspended. 4. A voltage compensation device for a rare earth permanent magnet motor, characterized in that it comprises: a double-winding transformer; The double-winding transformer includes a primary winding and a secondary winding, the primary winding is connected to a power supply; the secondary winding has at least one tap; When the induction potential of the rare earth permanent magnet motor is greater than the power supply voltage, the opposite end of the secondary winding is connected to the power supply, and the same end or a tap of the secondary winding is connected to the head end of the stator winding of the rare earth permanent magnet motor, so The end of the stator winding of the rare earth permanent magnet motor is connected to the neutral point of the motor. 5. The voltage compensation device of the rare earth permanent magnet motor according to claim 4, wherein the primary winding is connected to a power supply voltage, specifically: The first end of the primary winding is connected to the power supply, and the tail end of the primary winding has two taps, which are the first tap and the second tap from the tail end to the first end; The tail end, the first tap or the second tap is connected to the neutral point of the transformer. 6. The voltage compensation device of the rare earth permanent magnet motor according to claim 4, characterized in that, The end of the same name of the secondary winding or a tap is connected to the head end of the stator winding of the rare earth permanent magnet motor, specifically: the end of the same name of the secondary winding is connected to the head end of the stator winding of the rare earth permanent magnet motor, and the second end The tap of the winding is suspended; or, One tap of the secondary winding is connected to the first end of the stator winding of the rare earth permanent magnet motor, and the same-named end of the secondary winding is suspended.

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