JP2005287281A - Variable speed synchronous motor and motor-driven blower using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase centrifugal-force-withstanding strength of a rotor in a variable speed synchronous motor, to achieve reduction in space and cost cut of a control circuit, and to obtain an ultra-high speed, small, highly efficient motor-driven blower. <P>SOLUTION: A slip ring and a position-detecting ring are provided on the rotor and lap windings are wound on an iron core having multiple slots to form a rotating body that is well balanced and excellent in withstanding the centrifugal force. Stator windings comprise a main coil and an auxiliary coil connected in parallel, and by controlling the switching of a power switch in synchronization with a voltage signal detected by brushes contacted on a position detecting sensor ring, an AC voltage is supplied to the stator parallel windings. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

Detailed Description of the Invention

  The present invention relates to a variable speed synchronous motor for high speed rotation and an electric blower using the motor.

  Conventionally, universal motors are mainly used for motors for electric blowers used in vacuum cleaners, etc., but this motor rectifies the armature current with a commutator and a brush, so the brush life is shortened. In the case of higher speed and higher capacity, it has become a limit in use. Therefore, recently, a synchronous motor controlled by a semiconductor, particularly a three-phase brushless DC motor has been used. Although this motor has a long life, since permanent magnets are used for the rotor, there is still a limit to speeding up. In the permanent magnet embedded motor of Japanese Patent No. 2823817, as disclosed in a structure in which a magnet is embedded in an armature core, the rotor has a strengthened type, but the strength is still insufficient. Conventionally, a Hall IC is used to detect the rotational position, and a three-phase inverter circuit using a dedicated IC is often used as the drive control circuit. Furthermore, the stator core has a large number of slots formed on the inner periphery to form a distributed winding, and has a structure in which cooling air does not easily pass through the gap between the rotor and the stator.

Problems to be solved by the invention

  In a semiconductor control motor using such a synchronous motor at high speed, if the design of high speed rotation is advanced in order to reduce the size and weight, the rotor has a permanent magnet, so the centrifugal strength is insufficient. There was a problem that would do. Further, since the drive control circuit of the brushless DC motor is complicated, there is a problem that the storage space becomes large, which is contrary to the reduction in size and weight, and is expensive. Furthermore, since the Hall IC used for rotational position detection has a low operating voltage, it is necessary to provide a power supply separate from the main power supply and supply it to the motor, which is susceptible to the effects of external noise such as switching noise. there were. Furthermore, there is no cooling air path in the gap between the stator and the rotor, which has been problematic in that it reduces air blowing efficiency and increases the current density of the windings to reduce the size and material cost.

    The present invention was made in order to solve the rotor strength and cooling effect of the semiconductor control motor described above and the drawbacks of the sensor. The problem is that the rotor is connected to the slip ring, the power supply, and the power receiving brush. In this way, a DC current is passed through the rotor winding so that it is not destroyed by centrifugal force, and at the same time, the rotor core is made into multi-slots with an equal pitch and the like to obtain a good rotor balance as a lap winding. It is possible to improve the strength against centrifugal force. The stator winding is composed of only a main coil and an auxiliary coil or a main coil connected in parallel to the main coil, and has a simple structure for applying a single-phase AC voltage to both ends of the coil. Further, as the rotor magnetic pole position detecting means, a sensor ring and a sensor brush, or a similar non-contact device is provided. Accordingly, it is an object of the present invention to obtain a semiconductor control motor capable of making a drive circuit small and inexpensive, and a motor rotating at a higher speed, and an electric blower using the motor.

Means for solving the problem

  For this reason, the invention according to claim 1 has a rotor having a rotor winding to which an exciting current is supplied via a slip ring, a stator having a stator winding on a plurality of magnetic poles, and holding the stator. In a synchronous motor having a housing, the stator has a magnetic pole structure of a magnetic pole concentrated winding method, and a position detection sensor for detecting a rotor magnetic pole position is provided, and the stator winding is energized by a signal of the position detection sensor. It is like controlling the current.

    According to a second aspect of the present invention, in the variable speed synchronous motor according to the first aspect, the position detecting sensor includes a rotating body provided coaxially with the rotor, and a sensor magnetic brush position detecting sensor. Is to become.

    According to a third aspect of the present invention, in the variable speed synchronous motor according to the first or second aspect, the rotor is formed by forming magnetic poles on a rotor core having a plurality of slots by a lap winding. .

    According to a fourth aspect of the present invention, in the variable speed synchronous motor according to the first, second, and third aspects, the stator winding includes a main coil and an auxiliary coil, and the auxiliary coil is connected in parallel with the main coil. A phase advance capacitor is connected in series to form a rotating magnetic field component.

    According to a fifth aspect of the present invention, in the variable speed synchronous motor according to the first, second, third, and fourth aspects, the stator winding includes a main coil and an auxiliary coil formed by a bifilar winding, and a capacitor is connected in series. The auxiliary coil and the main coil are connected in parallel, and when the respective coils are excited, they are connected so that the magnetic poles of the stator are opposite in polarity, and the rotation is controlled by two semiconductor switches. is there.

    According to a sixth aspect of the present invention, in the variable speed synchronous motor according to the first, second, third, and fourth aspects, the stator winding includes a main coil and an auxiliary coil, and the auxiliary coil and the main coil connected in series with a capacitor. The coil is connected in parallel and the rotation is controlled by one semiconductor switch.

    A seventh aspect of the present invention is the variable speed synchronous motor according to the first, second, third, fourth, fifth or sixth aspect, wherein the stator winding and the rotor winding are connected in series.

  According to an eighth aspect of the present invention, in the variable speed synchronous motor according to the first, second, third, fourth, and sixth aspects, the stator winding and the rotor winding are connected in parallel, and the stator winding In this case, an alternating current is supplied to the rotor winding, a direct current is passed through the rotor winding, and the rotor winding current is controlled to control the operating characteristics.

  The invention described in claim 9 is that the variable speed synchronous motor described in claims 1, 2, 3, 4, 5, 6 is used as an electric blower.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings in the case of a combination of a 4-pole stator and a 2-pole rotor. The variable speed synchronous motor of the present invention can be easily realized with the same configuration in other multiphase motors, such as a combination of a 4-pole stator and a 4-pole rotor, a 2-pole stator and a 2-pole rotor, and the like. It is.

  (First Embodiment) FIG. 1 shows an electric blower using a variable speed synchronous motor of the present invention in which a half of one side is sectioned in the longitudinal direction. FIG. 2 is a plan view showing a stator magnetic pole, a stator winding, and a main circuit power transistor. FIG. 3 is a side view of the rotor, and FIG. 4 is a plan view showing the sensor brush and the sensor holder. In FIG. 1, the stator 2 is housed and fixed inside a cylindrical casing 6a. A rotor 3 is housed inside the stator 2, and both ends of the rotating shaft 9 are rotatably supported by bearings 8a and 8b attached to the central portions of the casings 6a and 6b. A centrifugal fan 7 is attached to the tip of the rotating shaft 9, and an air path from point A to point B indicated by an arrow is formed. This is an example in which the rotor 3 is provided with a slip ring 32 integrally provided with a sensor ring 32c. Further, the positive brush 33, the negative brush 34, and the sensor brushes 43a and 43b shown in FIG. 4 are brought into contact with the positive brush holder 10, the negative brush holder 11, and the sensor holder 40, respectively.

    The stator 2 has a magnetic pole structure capable of concentrated winding as shown in the stator winding connection diagram of FIG. 2, and sufficient cooling air is provided between the casing 2 and the rotor 3. The passage is formed. The four magnetic poles include a main winding 24 (24a, 24b) wound in series so as to form N and S poles on a pair of opposing magnetic poles 20, 22, and another adjacent opposing magnetic pole 21, An auxiliary coil 25 (25a, 25b) formed by connecting a capacitor 26 in series is wound so as to form N and S poles 23.

    As shown in FIG. 3, the rotor 3 includes an iron core 12 having a large number of slots, a winding 39, a slip ring 32 (a positive slip ring 32 a and a negative slip ring 32 b), and a sensor ring 32 c, and is fixed to the main shaft 9. ing. The sensor ring 32c is integrated with the positive electrode slip ring 32a with which the positive electrode brush 33 is brought into contact with the metal portion, and together with the negative electrode slip ring 34, is formed into the slip ring 32 by resin molding. From the positive and negative slip rings 33 and 34, a positive tongue 37 and a negative tongue 38 are drawn out, respectively, and a lap winding rotor winding 5 is wound as shown in a winding development view of FIG. Although only the coil position is shown in FIG. 5, by reducing the number of coils in the central part of the magnetic pole, heat generation can be reduced and a cooling passage can be secured. In the present embodiment, the sensor ring is integrated with the slip ring, but may be a separate structure.

    As shown in FIG. 4, the sensor holder 40 has a structure in which a holder metal 41 is attached to a holder substrate 41, and sensor brushes 43a and 43b are attached. When the rotor 3 rotates, the sensor brushes 43a and 43b become a positive potential when they are in contact with the metal part 32c of the sensor ring integrated with the positive electrode slip ring 33, and this is divided to obtain a pulse signal. It is supposed to be a structure.

    Next, the rotation operation will be described with reference to the serial and parallel drive circuit diagrams of the motor of the present invention shown in FIGS. 6 and 7 and the rotation principle explanatory diagram of the motor of the present invention shown in FIG. In the series drive circuit of FIG. 6, the rotor winding 5, the main winding 24 of the stator winding 4, and the capacitor 6 and the auxiliary winding 25 provided in parallel with the main winding 24 are connected to the power source voltage. Wired so as to be connected in series to + E0. H bridges are formed by FET power transistors Tr1, Tr2, Tr3, Tr4 at both ends C, D of the stator winding 4. The parallel drive circuit of FIG. 7 is such that the rotor winding is connected in parallel with the H bridge of the stator winding. The current flowing through the rotor winding is intermittently controlled by applying a voltage based on the chopper signal generated by the microcomputer 61 to the gate terminal T3 of the power transistor Tr15, thereby controlling the motor input and the rotational speed.

    Since the energization control to the stator winding by the H bridge is common to FIGS. 6 and 7, the control method will be described below with reference to FIG. When the positive voltage detected by the sensor brush 43a is input to the terminal T1 of the position detector 62, the voltage stepped down by the resistors R9 and R10 is input to the input port PI1 of the microcomputer 61 (hereinafter referred to as a microcomputer). The The microcomputer 61 outputs 0000 to the output ports P1 to P4 after a predetermined time programmed in advance (at this time, the voltage between the gates and sources of all the power transistors Tr1, Tr2, Tr3, Tr4 becomes zero and turns off) To output the 1001 state. Then, since the outputs of the inverters Iv1 and Iv4 are in the low [L] state, the light emitting diode D5 is turned off, and the phototransistor PT1 and the transistor Tr14 are also turned off. When the phototransistor PT1 becomes non-conductive, the transistor Tr5 is turned on, and thus the transistor Tr6 is turned off. As a result, the power transistor Tr1 is turned on and at the same time the transistor Tr11 is turned on, so that the power transistor Tr4 is turned on.

    Next, when the rotor 3 rotates based on the rotation principle described later, the sensor brush 43b becomes a positive voltage, and when the voltage is input to the terminal T2 of the position detector 62, the high voltage is input to the input port PI2 of the microcomputer 61. [H] signal is input, and 1010 is output to the output port after a predetermined time programmed in advance. Then, since the outputs of the inverters Iv2 and Iv3 are [L], the power transistors Tr2 and Tr3 are turned on by the same logic as that described above, and at the same time, Tr1 and Tr4 are turned off. In this way, the voltage between the CDs is an alternating voltage whose direction is switched between forward and reverse by the voltage signals of the sensor brushes 43a and 43b in the stator winding. With this switching, the magnetic energy stored in the main winding 24 and the auxiliary winding 25 of the stator winding 4 and the electric energy charged in the capacitor 26 are converted into the main winding 24, the auxiliary winding 25, and the capacitor. Thus, a circulating current is generated in the closed loop formed by 21 and absorbed by the winding resistance, and a large back electromotive force is prevented from being applied to the power transistors Tr1 to Tr4.

    FIG. 8 is an explanatory view of the rotation principle showing the relative position between the rotor and the stator of the motor of the present invention and the relationship between the sensor brush voltage and the stator winding voltage. The sensor brush output of the motor of the present invention rotates with the same angle as the rotor 3 as the rotor 3 rotates, and outputs [H] and [L] signals. Hereinafter, the rotation operation will be described with reference to FIG. At startup, the power transistors Tr1 to Tr4 are alternately turned on and off so that an alternating voltage having a predetermined frequency is applied to the CD terminal. Then, a rotating magnetic field is generated in the stator and the rotor is activated.

    First, the case where the rotor is at the relative position shown in FIG. If there is an [H] input at the input port PI1 of the microcomputer 61 at this position, the power transistors Tr1 and Tr4 are conducted, and a positive voltage is applied to the C terminal between the CD terminals of the stator winding 4. The stator magnetic pole 4 is excited first from the auxiliary winding 25 with a capacitor to generate a rotating magnetic field that rotates from the state (a) to the state (b) and further to the state (c). Following this, the rotor 3 also rotates as shown. (In this figure, only the magnetic pole display of the rotor 3 is shown, and the magnetic poles of the stator are omitted to show the direction of the energizing current of the winding.) If the load torque is smaller than the motor-generated torque, the rotor 3 The microcomputer 61 rotates to a position ahead of the rotation position, but when both the left and right sensor brushes 43a and 43b rotate to a position where the voltage is [L], the microcomputer 61 outputs 0000 to All the transistors Tr1 to Tr4 are turned off.

    Subsequently, when the rotor 3 rotates, the sensor brush 43b changes to [H]. At this time, the microcomputer 61 outputs the output port to 0110 after a predetermined dead time programmed in advance. To do. Then, the high-side power transistor Tr2 and the low-side power transistor Tr3 are turned on, and the D terminal becomes [H]. At this time, a rotating magnetic field that changes in the order of (d), (e), and (f) in FIG. The rotor 3 is rotated by the interaction between the rotating magnetic field and the DC magnetic field of the rotor 3, and the sensor brush 43b is rotated to a position where the sensor brush 43b becomes [L]. In the same manner, the rotor 3 rotates and continues to smoothly rotate from (g), (h) to the original state (a).

  Although the power supply voltage is not shown here, an appropriate DC arbitrary voltage is supplied from a commercial AC power supply by a known rectifier circuit or a power control circuit using a thyristor. Further, the position detection sensor can be other detection means such as a Hall IC in a motor other than claim 2. Here, the rotor is shown as a two-pole structure, but it is also easy to set the number of poles to four or more. Further, although the stator has four poles, it is obvious that it can be six or eight poles as required.

    (Second Embodiment) FIG. 9 is a plan view of a stator showing a stator winding which is controlled by two semiconductor switches using a stator winding as a bifilar winding. The main coil is wound around the magnetic poles 20 and 22 in opposite directions, and the auxiliary coil is wound around the magnetic poles 21 and 23 in opposite directions. Each of the main coil and the auxiliary coil is a bifilar winding in which two conductive wires are wound at the same time. The main coil is indicated by a solid line and the auxiliary coil is indicated by a dotted line.

    The rotation principle of the motor of the present invention generates a rotating magnetic field similar to that shown in the first embodiment, and will be described below with reference to FIG. In FIG. 8, when the signal of the sensor brush 43a changes to high, the power transistor Tr20 of FIG. 9 is turned on. Then, the magnetic poles 20 and 21 are magnetized to the N pole, and the magnetic poles 22 and 23 are magnetized to the S pole. At this time, due to the action of the capacitor connected in series with the auxiliary coil, 21 and 23 are magnetized earlier than the magnetic poles 20 and 22, and a rotating magnetic field is generated from (a) to (b) in FIG. 3 rotates clockwise. As the rotor 3 rotates, the opposing state of the rotor and the magnetic pole changes from the state of FIG. 8A to the states of FIG. 8B and FIG. 8C, and the sensor brush 43a changes to low. The power transistor Tr20 is turned off. The magnetic pole facing state changes to the state shown in FIG. Subsequently, when the signal of the sensor brush 43b changes to high, the power transistor Tr21 is turned on, and when the sensor brush 43b changes to low, the Tr21 is also turned off, so that the states shown in FIGS. The rotation operation can be continued.

    (Third Embodiment) FIG. 10 is a plan view of a stator showing a stator winding whose operation is controlled by one semiconductor switch. FIG. 11 is an explanatory view showing the rotation principle of the motor of the present invention. In this embodiment, only one sensor brush 43a is provided. When the brush signal of the sensor brush 43a becomes high (when the magnetic poles are opposed to each other in FIGS. 11A to 11D), the power transistor Tr22 is turned on. The effect of the auxiliary coil in which the capacitors are connected in series creates a clockwise rotating magnetic field in the half-rotation part as shown in FIG. 11, so that the rotor 3 rotates smoothly, and in the other half-rotation part, the coasting operation The rotation in the acceleration cycle shown in FIGS. 11A, 11B, 11C, 11D is performed again from the magnetic pole facing state shown in FIGS. 11E, 11F, 11G, and 11H.

    Further, at the time of start-up, the power transistor Tr22 is intermittently connected in a short period. When the rotor 3 is in the magnetic pole facing state shown in FIGS. 11E to 11H, the brush signal of the sensor brush 43a is low. In this case, the rotor 3 is It rotates in the reverse direction for a short time, and after a maximum half rotation, it vibrates and rotates in response to the forward rotation torque. However, the period during which the sensor brush 43a is in a high signal is continuously turned on, and the average torque is rotated clockwise in the positive direction. As a result, the rotor 3 can shift to the continuous rotation state in a short time.

    FIGS. 11E to 11H show a state where the power transistor Tr22 is non-conductive and no current flows through the stator winding, but the rotor winding is provided in parallel with the stator winding. It shows a case where it is in a conductive state. Even if the rotor windings are connected in series and controlled by the power transistor Tr22, it is clear that the rotation principle is the same, and that rotation at start-up and continuous rotation can be performed. Further, the relationship between the stator and the rotor can be switched to allow an alternating current to flow through the rotor. Further, in this embodiment, a two-phase split type (stator 4 poles, rotor 2 poles) is used. Although an example has been shown, as shown in FIG. 12, even in the case of only a main coil, no auxiliary pole and no auxiliary winding, two stator poles, two rotor poles, etc. It is clear that continuous rotation is practical.

The invention's effect

    Since the invention of the variable speed synchronous motor according to claim 1 has a rotor winding structure that supplies an excitation current via a slip ring, a strong rotating body with high anti-centrifugal force can be obtained. There is an effect that a high-speed motor can be obtained. In addition, since the stator has a structure having a good ventilation cooling effect as a magnetic pole structure of the magnetic pole concentrated winding method, the conductor diameter can be reduced, the copper weight can be reduced, and the efficiency can be improved. In addition, since a rotor position detection sensor is provided and the current supplied to the stator winding or the rotor winding is controlled by the signal of the position detection sensor, the effect of a variable speed synchronous motor without risk of step-out is obtained. There is.

    The invention described in claim 2 is the variable-speed synchronous motor according to claim 1, wherein the variable speed synchronous motor is a mechanical magnetic pole position detection sensor provided with a rotating body and a power receiving brush provided coaxially with the rotor. The motor can be stored in the minimum space without increasing the volume of the motor, and the motor can be controlled at a variable speed with an inexpensive and space-saving circuit, and can be a highly reliable motor that is resistant to noise and does not malfunction. There is.

    According to a third aspect of the present invention, in the variable speed synchronous motor according to the first or second aspect, the rotor is formed by forming a magnetic pole by a lap winding on a rotor core having a plurality of slots. As a result, the winding covers the strength weakness of the tooth portion of the rotor core, and has the effect of enabling higher speed operation. In addition, since the windings can be symmetrically distributed and easily balanced, there is an effect that the rotating body can be reduced in vibration and noise.

    According to a fourth aspect of the present invention, in the variable speed synchronous motor according to the first, second, and third aspects, the stator winding includes a main coil and an auxiliary coil, and the auxiliary coil is connected in parallel with the main coil. Since the phase advance capacitor is connected in series, the back electromotive voltage applied to the power transistor can be reduced, and the operation efficiency at high speed can be increased. In addition, the rotating magnetic field generated by the stator magnetic pole becomes smooth, vibrations are reduced, and higher speed operation is possible.

    According to a fifth aspect of the present invention, in the variable speed synchronous motor according to the fourth aspect, even if the number of power transistors is two, smooth rotation can be obtained with low vibration, circuit space can be reduced, and economy is excellent. The variable speed motor can be obtained.

    According to the sixth aspect of the present invention, in the variable speed synchronous motor according to the fourth aspect, the number of power transistors can be reduced to one, and there is an effect that an inexpensive variable speed motor can be obtained with a minimum circuit space.

    A seventh aspect of the invention is the variable speed synchronous motor according to the first, second, third, fourth, fifth, and sixth aspects, wherein the stator winding and the rotor winding are connected in series. Even in the case of a high voltage motor and a motor with a large capacity exceeding 1 KW, it is possible to employ a cheaper low withstand voltage power transistor, which has the effect of reducing the inrush current at the time of startup.

    According to an eighth aspect of the present invention, in the variable speed synchronous motor according to the first, second, third, fourth, and sixth aspects, the stator winding and the rotor winding are connected in parallel, and the stator winding Since the AC current is supplied to the rotor coil and the DC current is supplied to the rotor winding and the rotor winding current is controlled to control the operation characteristics, the power control of the rotor can be easily performed by the microcomputer, and the field weakening As a result, the speed can be further increased.

  The ninth aspect of the invention is an electric blower using the variable speed synchronous motor according to the first, second, third, fourth, fifth, and sixth aspects. It can be a rotating body with a small balance, can be rotated at high speed with lower vibration, can be a space-saving and inexpensive circuit, and can be a highly efficient blower with high cooling effect and low air path loss. There is.

  It is a partial longitudinal cross-section outline figure which shows the whole structure of the electric blower using the variable speed synchronous motor in this invention.     It is a top view which shows the stator magnetic pole of 1st Example, a stator coil | winding, and a power transistor.     It is a side view which shows the rotor which has a slip ring and a sensor ring.     It is a top view which shows a sensor brush and a sensor holder.     It is a winding development view showing a rotor winding.     It is a drive circuit diagram of a serial connection type of the present invention motor rotor winding and stator winding.     It is a drive circuit diagram of a parallel connection type of the present invention motor rotor winding and stator winding.     It is rotation principle explanatory drawing of this invention motor 1st, 2nd Example.     It is a top view which shows the stator magnetic pole of 2nd Example, a stator coil | winding, and a power transistor.     It is a top view which shows the stator magnetic pole of 3rd Example, a stator coil | winding, and a power transistor.     It is rotation principle explanatory drawing of this invention motor 3rd Example.     It is a modification of this invention motor 3rd Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electric blower 2 Stator 3 Rotor 4 Stator winding 5 Rotor winding 6a, 6b Casing 7 Centrifugal fan 8a, 8b Bearing 10 Positive electrode brush holder 11 Negative electrode brush holder 32 Slip ring 33 Positive electrode brush 34 Negative electrode brush 40 Sensor holder

Claims (9)

In the synchronous motor having a rotor having a rotor winding to which an excitation current is supplied via a slip ring, a stator having a plurality of magnetic poles and a stator winding, and a casing for holding the stator, the fixing The rotor has a magnetic pole structure of a magnetic pole concentrated winding system, and a position detection sensor for detecting the rotor magnetic pole position is provided, and the energization current of the stator winding is controlled by the signal of the position detection sensor. Variable speed synchronous motor. 2. The variable speed synchronous motor according to claim 1, wherein the position detection sensor is a mechanical magnetic pole detection sensor including a rotating body provided coaxially with the rotor and a sensor brush. The variable-speed synchronous motor according to claim 1, wherein the rotor is formed by forming magnetic poles on a rotor core having a plurality of slots by lap winding. 4. The stator winding according to claim 1, wherein the stator winding includes a main coil and an auxiliary coil, and the auxiliary coil is connected in parallel with the main coil, and a phase advance capacitor is connected in series. Variable speed synchronous motor. The stator winding includes a bifilar winding main coil and an auxiliary coil, and when two coils in which an auxiliary coil having a capacitor connected in series and a main coil are connected in parallel are provided and each coil is excited 5. The variable speed synchronous motor according to claim 4, wherein the magnetic poles of the stator are connected so as to have opposite polarities. 5. The variable speed synchronous motor according to claim 4, wherein the stator winding includes a main coil and an auxiliary coil, and an auxiliary coil having a capacitor connected in series and the main coil are connected in parallel. The variable speed synchronous motor according to claim 1, 2, 3, or 4, wherein the stator winding and the rotor winding are connected in series. The stator winding and the rotor winding are connected in parallel, an alternating current is passed through the stator winding, a direct current is passed through the rotor winding, and the operating characteristics are controlled by controlling the rotor winding current. The variable speed synchronous motor according to claim 1, 2, 3, or 4. An electric blower using the variable speed synchronous motor according to any one of claims 1 to 6.

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