JP2005065363A - Inverter surge resistant motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low voltage motor in which insulation is prevented from deteriorating between windings by lightening the part of steep surge voltage being burdened between the windings. <P>SOLUTION: After conductors 11-14 consisting of two wires A and B are wound by one half of the number of turns of the motor winding in a low voltage motor, the conductors 11-14 are divided into start-of-winding conductors A1, B2, A5 nd B6 and end-of-winding conductors A3, B4, A7 and B8 and then A3-B2 (joint 20), B4-A5 (joint 21) and B6-A7 (joint 22) are connected externally. Capacitors 26-29 for adjusting inter-winding distributed capacitance are connected, respectively, between A1-20, 20-21, 21-22 and 22-B8 in order to improve the voltage being burdened between the windings. Insulation can be prevented from deteriorating between windings by lightening the part of steep surge voltage being burdened between the windings. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a motor driven by an inverter, and more particularly to a structure and a manufacturing method of a low-voltage motor using concentrated winding random winding coils.
[0002]
[Prior art]
In recent years, inverter power supplies have been widely used to drive motors for the purpose of energy saving. However, when a motor is driven by an inverter power source, it has been reported that a steep surge voltage generated by the inverter causes a higher voltage than the conventional commercial frequency power source driving between the motor windings (for example, Non-patent document 1).
[0003]
By the way, in high-voltage static induction devices such as high-voltage rotating machines such as high-voltage motors and high-voltage generators, high-voltage transformers, and reactors, lightning impulses, open / close surges of vacuum circuit breakers, etc., before the steep surge voltage of the inverter became a problem The voltage distribution has been widely studied with respect to the high-voltage surge voltage (see, for example, Non-Patent Document 2). Specifically, the electromagnetic winding is approximated by a circuit formed by the distributed capacitance between the windings and the ground distributed capacitance of each part of the winding, and the voltage distribution when the unit step voltage is applied is calculated. It is described that the shared voltage between windings can be analyzed.
[0004]
In addition, if the ground distributed capacitance of each part of the winding is designed to be larger than the distributed capacitance between the windings, the initial potential distribution approaches a straight line, and the shared voltage between the windings decreases. For this reason, the high voltage induction device is designed such that the ground distributed capacitance of each part of the winding is larger than the distributed capacitance between the windings. Furthermore, in a high-voltage motor, a method of relaxing a shared voltage between windings by connecting a capacitor for adjusting distributed capacitance between windings from the outside of the windings has been proposed (see, for example, Patent Document 1). . In the three-phase winding device, as shown in FIG. 6, the shared voltage of the windings 31, 41, 51 and winding ends 32, 42, 52 of the windings 30, 40, 50 of each phase increases. For this reason, in Patent Document 1 described above, it is proposed to connect an interwinding distributed capacitance adjusting capacitor to these coils.
[0005]
On the other hand, conventionally, in the low voltage motor of less than 1 kVrms, the above-described countermeasure for relaxing the shared voltage between the windings against the steep surge voltage has not been taken. This is because conventional high-voltage surges such as lightning surges and switching surges were not a problem for low-voltage motors. In general, motor windings are manufactured with random windings and concentrated windings for low-voltage motors. This is because it was difficult to control the distributed electrostatic capacity and the ground distributed electrostatic capacity of each part of the winding to alleviate the shared voltage. In addition, when a coil is wound at once without cutting the magnet wire with a concentrated winding motor, the conductor of the coil series connection part cannot be taken out after the motor is manufactured. This is because the capacitor for adjusting the distributed capacitance could not be connected.
[0006]
[Non-Patent Document 1]
IEEJ Technical Report No. 739, p. 14-20
[Non-Patent Document 2]
Masayuki Ieda, Contemporary High Voltage Engineering, Ohmsha, p. 91-93
[Patent Document 1]
Japanese Patent Laid-Open No. 50-000301
[Problems to be solved by the invention]
The present invention is characterized in that, in a low-voltage motor that has been actively driven by an inverter in recent years, the voltage sharing between the windings is reduced with respect to the steep surge voltage to prevent the insulation deterioration between the windings. An object of the present invention is to provide a low-voltage motor.
[0008]
[Means for Solving the Problems]
The effects of the present invention can be obtained by the following method. That is, after winding 2n conductors (n is an integer) by half the number of windings of the motor winding, the winding start and end winding conductors are divided into two, and the winding start n and winding end n A motor with externally connected conductors is manufactured. In addition, when connecting a distributed capacitance adjusting capacitor between windings to improve the shared voltage between windings, the connection part at the beginning and end of winding of the motor winding, and the winding start part of the winding This can be realized by connecting a capacitor between the inter-electrode wire and the winding end.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0010]
[Example 1]
A method and structure for manufacturing a motor winding in which a capacitor for adjusting distributed capacitance between windings is connected to the outside according to the first embodiment of the present invention will be described. 1-3 show the manufacturing method and structure for one phase of the motor winding. 1 shows the winding process of the motor winding, FIG. 2 shows the separation and connection process of the motor winding, and FIG. 3 shows the external capacitor connecting process and the completed drawing of the winding. In addition, all are shown in the coil | winding expansion | deployment figure when seeing the stator of a motor from the inner peripheral side. The shaded area indicates the teeth of the stator core of the motor.
[0011]
In the winding process of FIG. 1, two enamel wires are wound at the same time to produce one-pole windings 11 and 12 and one-pole windings 13 and 14 composed of two enamel wires A and B. .
[0012]
Subsequently, in the process of FIG. 2, the two enamel wires A and B at the winding start portion of the winding 11 are connected to the wires A1 and B2, and the two enamel wires at the end of winding of the winding 12 are connected to the wire A3 and the wires. It divides into B4 and welds and connects the electric wire B2 and the electric wire A3 to form the welded portion 20. Similarly, the enameled wires A and B at the winding start portion of the winding 13 are divided into the electric wires A5 and B6, and the enameled wires A and B at the winding end of the winding 14 are divided into the electric wires A7 and B8. The welding part 22 is formed by welding and connecting the electric wire A7. Further, as the interelectrode connection, the wire B4 at the end of winding of the winding 12 and the wire A5 at the start of winding of the winding 13 are welded and connected to form the welded portion 21.
[0013]
3, the inter-winding distributed capacitance adjusting capacitors 26 to 29 are connected to the electric wire A1 and the welded portion 20, the welded portion 20 and the welded portion 21, the welded portion 21 and the welded portion 22, and the welded portion of the winding 11. 22 and the wire B8 of the winding 14 are connected to manufacture the winding.
[0014]
An equivalent circuit of the winding obtained by this manufacturing method is shown in FIG. That is, the one-phase winding 60 is formed from the windings 61 to 64. Each of the windings 61 to 64 is formed of an inductance 65, a distributed capacitance 66 between the windings, and a ground distributed capacitance 67 of each part of the winding. In FIG. 4, the inter-winding distributed capacitance adjusting capacitors are shown as capacitors 81 to 84.
[0015]
FIG. 5 shows a calculation result of the coil sharing voltage when a unit step voltage having a rise time of 0.1 μs is applied to the motor manufactured by the above method. In the coil sharing voltage, the value of the unit step voltage application side first coil is shown with the step voltage peak value being 100%. The equivalent circuit of FIG. 4 and EMTP (Electro Magnetic Transients Program) were used for the calculation of the coil sharing voltage.
[0016]
The circuit constants in FIG. 5 are based on the measurement results of the actual motor, the distributed capacitance 66 between the windings is 1,000 pF, the ground distributed capacitance of each part of the winding is 1,000 pF, and the windings connected to the outside As a result, the capacitance of the inter-distribution capacitance adjusting capacitors 81 to 84 was set to 1,000 pF. For simplicity, calculation was performed with the inductance 65 open as in Non-Patent Document 2. As a result, the coil sharing voltage could be reduced by 50% compared to Comparative Examples 1 and 2 of the conventional motor winding structure described later. At the same time, the surge withstand voltage of the motor can be improved by a factor of two compared to the conventional comparative examples 1 and 2, and a more reliable motor can be provided in which insulation deterioration hardly occurs between the windings even when the inverter is driven. .
[0017]
In the above-mentioned Example 1, it was shown that the surge voltage can be improved and the reliability can be improved with reference to the case where a magnet wire having the same film thickness and material as the conventional motor winding is used. However, in particular, if the coil-sharing voltage is made smaller than the partial discharge voltage between the magnet wires, the surge voltage of the motor can be improved while preventing the occurrence of insulation deterioration between the motor windings. . For this reason, by selecting an appropriate magnet wire that satisfies this condition with respect to the necessary surge withstand voltage, the space factor can be improved as compared with the conventional motor, and the size of the motor can be reduced.
[0018]
In the above-described Example 1, an enameled wire is used for the magnet wire, but a copper wire wrapped with silk, paper, cotton, glass cloth or the like may be used. In addition, various enamel-coated wires such as polyamideimide, polyesterimide, polyimide, polyester, formal, polyurethane, epoxy, silicone, and Teflon (registered trademark) film can be used for the enameled wire. In the present invention, it is particularly desirable to color the surface of the electric wire or the insulating film. This is because it is easy to distinguish the electric wires to be divided when dividing the 2n electric wires of the present invention into two. However, when no colorant or paint is used, the continuity of the winding may be checked with a tester, and 2n wires may be divided into two and connected.
[0019]
[Example 2]
The second embodiment is a motor winding in which the inter-winding distributed capacitance adjusting capacitor of the first embodiment is not connected. In general, the thickness of an insulating film of a magnet wire such as an enamel wire used for a winding is several tens of μm, which is sufficiently thinner than a thickness of several hundreds of μm of an insulator between the winding and the core (ground). For this reason, if the distributed electrostatic capacitance between the windings can be used, the shared voltage between the motor windings can be relaxed without connecting the inter-winding distributed capacitance adjusting capacitor outside the motor.
[0020]
FIG. 5 shows a calculation result of the coil sharing voltage when a unit step voltage having a rise time of 0.1 μS is applied to the motor of the second embodiment. Even if the inter-winding distributed capacitance adjusting capacitor is not connected, the coil sharing voltage can be reduced by 37% compared to the conventional comparative examples 1 and 2. As a result, the surge withstand voltage of the motor can be improved by 1.6 times compared to the conventional comparative examples 1 and 2, and a more reliable motor that hardly causes insulation deterioration between the windings even when the inverter is driven. Can be provided.
[0021]
In the second embodiment, since the capacitive coupling of the coil at the start and end of winding of the motor winding is stronger than in the conventional case, the voltage sharing of the high-frequency voltage to the coil at the start or end of winding is greater than in the conventional case. It is thought that concentration was reduced. That is, in the case of an equivalent circuit, in the motor winding structure of the present invention, as shown in FIG. 4, the distributed capacitance between the windings is directly connected from the winding start side to the winding end side. The capacitive voltage distribution of the line tends to be uniform.
[0022]
In contrast, FIG. 7 shows an equivalent circuit of a conventional motor winding. The one-phase winding 90 is formed of windings 91 to 94, and the windings 91 to 94 are formed of an inductance 95, a distributed capacitance 96 between the windings, and a ground distributed capacitance 97 of each part of the winding. Is done. In the conventional winding structure, since the distributed electrostatic capacitance 96 between the motor windings is connected in series from the beginning of winding to the end of winding, capacitive coupling from the winding start side to the winding end side becomes weak, It is thought that a lot of voltage is shared on the winding start side.
[0023]
[Comparative Example 1]
The motor winding was manufactured by the conventional concentrated winding coil manufacturing method. The same enameled wire as in Examples 1 and 2 was used for the motor winding. Further, no interwinding distributed capacitance adjusting capacitor is connected outside the motor winding.
[0024]
FIG. 5 shows a calculation result of the coil shared voltage when a unit step voltage having a rise time of 0.1 μs is applied to the motor winding of Comparative Example 1. In Comparative Example 1, the step voltage is almost 100% and is shared by the first coil. For this reason, when the motor of the comparative example 1 is driven by an inverter, the insulation must be reinforced compared to the conventional sine wave drive.
[0025]
[Comparative Example 2]
The motor winding was manufactured by the conventional concentrated winding coil manufacturing method. The same enameled wire as in Examples 1 and 2 was used for the motor winding. In Comparative Example 2, the inter-winding distributed capacitance adjusting capacitor was connected between the winding start of the motor winding of Comparative Example 1 and the inter-electrode crossing wire, and between the inter-electrode crossing wire and the winding end.
[0026]
FIG. 5 shows the calculation result of the coil sharing voltage when a unit step voltage having a rise time of 0.1 μs is applied to the motor winding of Comparative Example 2. In Comparative Example 2, as in Comparative Example 1, the step voltage is almost 100% shared by the first coil. For this reason, when the motor of the comparative example 2 is driven by an inverter, the insulation must be reinforced as compared with the conventional sine wave drive.
[0027]
In Comparative Example 2, the reason why the shared voltage of the first coil could not be improved can be considered as follows. That is, when the winding of FIG. 8 is shown as an example, when the concentrated winding coils 111 to 114 are wound without cutting the magnet wire as in the conventional winding manufacturing method, only the crossing wire 120 appears outside the motor. Therefore, the capacitors 121 and 122 for adjusting the distributed capacitance between the windings can be connected only between the winding start 101 and the inter-electrode crossing wire 120 and between the inter-electrode crossing wire 120 and the winding end 104. As a result, the inter-winding voltage sharing between the winding start coil 111 and the winding end coil 113 having the largest shared voltage between the windings cannot be relaxed, and is almost the same as in Comparative Example 1 in which the distributed capacitance adjusting capacitor is not connected. It is thought that it became a shared voltage.
[0028]
【The invention's effect】
As described above, after winding 2n conductors (n is an integer) by half the number of windings of the motor winding, the winding start and end conductors are divided into two, and the winding start n windings A motor in which the last n conductors are connected externally is manufactured. In addition, when connecting a distributed capacitance adjusting capacitor between windings to improve the shared voltage between windings, the connection part at the beginning and end of winding of the motor winding, and the winding start part of the winding By connecting a capacitor between the inter-electrode crossing line and the winding end part, it is possible to relax the voltage sharing between the motor windings. At the same time, the surge voltage of the motor can be improved as compared with the conventional one, and a more reliable motor can be provided in which insulation deterioration is unlikely to occur between the windings even when the inverter is driven.
[Brief description of the drawings]
FIG. 1 shows a winding process of a motor winding according to the present invention.
FIG. 2 shows motor winding separation and connection process.
FIG. 3 is a completed drawing of an external capacitor connection process and windings.
FIG. 4 is an equivalent circuit of a motor winding according to the present invention.
FIG. 5 shows a motor winding first coil shared voltage when a unit step voltage is applied.
FIG. 6 is a winding diagram of a motor winding.
FIG. 7 is an equivalent circuit of a conventional motor winding.
FIG. 8 is a connection diagram of a conventional motor winding and a capacitor for adjusting distributed capacitance between windings.
[Explanation of symbols]
A1: 1/2 of winding start of motor winding 11A, B2: 1/2 of winding start of motor winding 11B, A3: 1/2 of winding end of motor winding 12A, B4: winding of motor winding 12B 1/2 of the end, A5: 1/2 of the winding start of the motor winding 13A, B6: 1/2 of the winding start of the motor winding 13B, A7: 1/2 of the winding end of the motor winding 14A, B8: 1/2 of the winding end of the motor winding 14B, 11: motor first winding, 12: motor winding, 13: motor third winding, 14: motor fourth winding, 20: motor winding B2, Connection part of A3, 21: Connection part of motor windings B4 and A5, 22: Connection part of motor windings B6 and A7, 26-29: Capacitor for adjusting distributed capacitance between windings, 60: Motor winding 1 Phase: 61: Motor first winding, 62: Motor winding, 63: Motor first Winding, 64: Fourth motor winding, 65: Inductance of motor winding, 66: Distributed capacitance between motor windings, 67: Capacitance between each part of motor windings, 71: Motor winding winding Start terminal, 74: Motor winding end terminal, 80: Spacing wire, 81-84: Inter-winding distributed capacitance adjusting capacitor, 30: U phase winding, 31: U phase winding start coil, 32 : U-phase winding end coil, 40: V-phase winding, 41: V-phase winding start coil, 42: V-phase winding end coil, 50: W-phase winding, 51: W-phase winding start coil, 52: W-phase winding End coil, 90: Motor winding for one phase, 91: Motor first winding, 92: Motor second winding, 93: Motor third winding, 94: Motor fourth winding, 95: Motor winding Inductance, 96: Distributed capacitance between motor windings, 97: Motor 101: Motor winding winding start terminal, 104: Motor winding winding end terminal, 111: Motor first winding winding, 112: Motor second winding, 113: Motor third winding 114: motor fourth winding, 120: crossover wire, 121, 122: inter-winding distributed capacitance adjusting capacitor

Claims (3)

After winding 2n conductors (n is an integer) by half the number of windings of the motor winding, the winding start and end winding conductors are divided into two, n winding start and n winding end A low-pressure motor characterized in that the conductor is connected externally. The feature is that the capacitor for adjusting the distributed capacitance between windings is connected to the external connection part of the n windings at the beginning and end of winding of the motor winding and at the end of winding. And low pressure motor. 2. The low-voltage motor according to claim 1, wherein a magnet wire used for discrimination when a 2n conductor is divided into two by applying or mixing an identification paint or dye.

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