JP2006158166A - Sensorless synchronous motor, and its driving method and device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sensorless synchronous motor which can obtain highly efficient output and a stable starting torque in spite of its small size, can easily detect the rotational position of a rotor at the time of starting and rotation and can improve controllability at the time of starting and rotation, and also provide its driving method and device. <P>SOLUTION: In the structure of a rotor 3, one magnetic pole is exposed on the surface of the rotor 3 as a magnet 7, while the adjacent other magnetic pole is formed as a yoke section 8. The exposure of the magnet 7 enables an effective use of the magnetic flux generating a rotational force. The rotor, wherein the adjacent magnetic pole of the magnet is the yoke section 8, has saliency, and can obtain highly efficient output and a stable starting torque even if reduced in size and can be easily treated. The difference of inductance of a drive coil 6 by the magnet and the yoke part is great, the detection voltage displaying the difference has a good S/N ratio, and signal processing is easy and a high detection accuracy can be obtained. The detection voltage can be easily detected at the time of starting and rotation and starting characteristics and the controllability at the time of rotation is improved. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a sensorless synchronous motor and a driving method and apparatus thereof, and has a structure capable of obtaining a high-efficiency output and a stable starting torque even when downsized, and easily detecting the rotational position of a rotor at the time of starting and rotating. The present invention relates to a sensorless synchronous motor having improved starting characteristics and controllability during rotation, and a driving method and apparatus therefor.

  Conventionally, as described in Patent Document 1, a sensorless synchronous motor (hereinafter, the motor is referred to as a motor) is known. In a sensorless synchronous motor, a magnet is arranged on the rotor side, a drive coil is wound on the stator side, the rotational position of the rotor is detected from voltage and current without using a rotational position sensor, and the stator side is based on this rotational position. The drive coil current is controlled to generate a rotating magnetic field, and the rotor is rotated. As this synchronous motor, N pole magnets 107N and S pole magnets 107S are alternately arranged on the surface of the yoke portion 108 constituting the rotor 102 as shown in FIG. 5A due to the difference in arrangement of the magnets on the rotor side. The surface magnet structure (SPM) type that is disposed and fixed to the magnet, and the N pole magnet 107N and the S pole magnet 107S inside the yoke portion 108 constituting the rotor 102 as shown in FIG. 5B. Some are of the embedded magnet structure (IPM) type embedded alternately. The IPM type synchronous motor has a salient pole structure 110 with a high magnetic permeability between the magnetic poles when the large machine is rotated at high speed, and generates reluctance torque in addition to the magnet torque. As a motor with high efficiency and a wide variable speed range, it is widely used in compressors, spindle motors, electric vehicle motors, and the like.

  In the sensorless synchronous motor drive control described above, a method for detecting the rotational position of the rotor without a sensor is described in Patent Document 1, in which the phase of the stator side drive coil including the rotational position information of the rotor is described. There is a method for detecting the rotational position of the rotor based on the current or the voltage induced in the drive coil. Such sensorless drive control is based on the premise that the rotor is in a rotating state. However, since the rotor is stopped at the time of starting, the rotational position of the rotor cannot be detected, and sensorless drive control cannot be performed. Therefore, if the rotor is rotated and started in accordance with the logic for rotating the rotor in the forward direction while passing the drive current sequentially through the drive coil without knowing the rotational position of the rotor, the rotor is stopped at the initial stage. Depending on the rotation direction, the rotation direction may be opposite to the intended rotation direction, or the rotation may not start. As described above, the sensorless drive control has a problem in the starting characteristics. Note that the starting torque cannot be stably obtained with the SPM type synchronous motor. In order to stably obtain the starting torque, the salient pole structure of the IPM type synchronous motor is a necessary condition.

As a solution to the problem of the starting characteristic as described above, in order to detect the position by discriminating the N pole and the S pole of the rotor at the time of stopping, a relatively large current is passed through the stator driving coil, and the opposite rotor side There is a method of detecting the difference in inductance of the drive coil due to the saturation / unsaturation state of the magnet (see Patent Document 2). In other words, when the magnetic flux of the magnet and the magnetic flux of the stator due to the drive coil current are in the same direction, the magnetic flux from the stator is further magnetized from the viewpoint of the magnet. . That is, since the magnet acts as a nonmagnetic material, the inductance of the drive coil is minimized. On the other hand, when the magnetic flux of the magnet and the magnetic flux of the stator due to the drive coil current are in opposite directions, the magnetic flux from the stator is magnetized in the opposite direction as seen from the magnet. The nature of That is, since the magnet acts as a magnetic body, the inductance of the drive coil is maximized. This is a method for detecting the position by discriminating whether the magnetic pole of the rotor at the time of stoppage is the N pole or the S pole based on the difference in inductance. By controlling the drive current based on the detected magnetic pole position when the rotor is stopped, the sensorless synchronous motor can be smoothly rotated in the intended direction from the initial stage, and the starting characteristics can be improved. I can do it.
Japanese Patent Laid-Open No. 08-308286 Japanese Patent Laid-Open No. 2004-040943

  However, the above conventional technique has the following problems. That is, as a first problem, an IPM type motor having a salient pole structure that can stably obtain a starting torque is a necessary condition as a synchronous motor to which the above-described conventional technology can be applied. A large synchronous motor with an output of more than kilowatts can easily create a salient pole structure, but a small synchronous motor with an output of less than 1 kilowatt to several tens of watts is less likely to adopt a salient pole structure. was there. One of the reasons is that when a salient pole structure is adopted as shown in FIG. 5 (b), the rotor magnetic flux is short-circuited inside the yoke, and due to processing limitations, the rotor This is because the gap between the stators cannot be reduced, so that the effective magnetic flux that can be used to generate the rotational force by the interaction with the stator outside the rotor is reduced and the efficiency is lowered. Another reason is that the smaller the size is, the more difficult it is to embed the magnet in the rotor to provide the salient pole structure due to the limitations of the processing. This is also a problem that it is difficult to reduce the size of the IPM type synchronous motor.

  As a second problem, when detecting the position by identifying the N pole and S pole of the stopped rotor facing the stator by the difference in inductance of the drive coil due to the saturation / unsaturation state of the rotor magnet, Since the difference in inductance is small, the S / N ratio is poor, the signal processing is complicated, and the detection accuracy is low.

  The present invention has been made to solve the above-described problem, and even when downsized, a high-efficiency output and a stable starting torque can be obtained, and the rotational position of the rotor is easy not only during rotation but also during startup. It is an object of the present invention to provide a sensorless synchronous motor, a driving method thereof, and a device capable of improving the starting characteristics and controllability during rotation.

  In order to achieve the above object, in a sensorless synchronous motor according to the present invention, one of the N poles and S poles formed by a magnet is arranged as one magnetic pole on the rotor surface facing the stator. The rotor surface adjacent to the magnetic pole is characterized in that the other magnetic pole of the N pole and S pole formed by the yoke portion is arranged.

  Alternatively, according to the sensorless synchronous motor described above, one of the N pole and the S pole formed by the magnet that is the one magnetic pole, and the N pole formed by the yoke portion that is a magnetic pole adjacent to the one magnetic pole. And the other magnetic pole of the S poles constitutes a rotor having a multipolar structure.

  In order to achieve the above object, the sensorless synchronous motor driving method according to the present invention is a driving method for the sensorless synchronous motor described above, which measures or represents the inductance of each driving coil that is stopped. It is detected that the value representing this inductance is minimum when the rotor surface facing the stator wound with the drive coil is a magnet having a low permeability, and is maximum when the yoke portion has a high permeability. Then, a position detection signal is generated that represents the stop position of the magnet and yoke part on the rotor surface and the stop position of the magnetic pole that is uniquely determined from the stop position, from the measured or detected inductance of each drive coil. The driving at the start is performed based on the generated position detection signal.

  Alternatively, the driving method of the sensorless synchronous motor according to the present invention is a driving method for the above-described sensorless synchronous motor, and measures what represents the inductance of each driving coil by interrupting the driving during rotation at regular intervals. Alternatively, it is detected that the value representing this inductance is minimized when the rotor surface facing the stator around which the drive coil is wound is a magnet having a low permeability, and is maximized when the yoke portion has a high permeability. Then, a position detection signal that represents the rotation position of the magnet and the yoke portion on the rotor surface and the rotation position of the magnetic pole uniquely determined from these rotation positions is generated from the measured or detected inductance of each drive coil. Then, the driving during rotation is continued based on the generated position detection signal.

  Alternatively, according to the driving method of the sensorless synchronous motor described above, after driving at the start based on the position detection signal generated from the one representing the inductance of each driving coil measured or detected during the stop, The driving during rotation is continued based on the position detection signal generated from the one representing the inductance of each drive coil measured or detected.

  In order to achieve the above object, a sensorless synchronous motor drive device according to the present invention is a drive device intended for the sensorless synchronous motor described above, and means for measuring or detecting the one representing the inductance of each drive coil. And, using the fact that this inductance represents the minimum when the rotor surface facing the stator around which the drive coil is wound is a magnet with a low permeability and the maximum when the rotor is a yoke with a high permeability, Means for generating a position detection signal representing the rotation position of the magnet and yoke part on the rotor surface and the rotation position of the magnetic pole uniquely determined from these rotation positions from the measured or detected inductance of each drive coil; And means for driving at the time of starting based on the generated position detection signal.

  Alternatively, a sensorless synchronous motor drive device according to the present invention is a drive device for the above-described sensorless synchronous motor, which interrupts driving during rotation at regular intervals and represents the inductance of each drive coil. Means for measuring or detecting, and what represents this inductance is minimum when the rotor surface facing the stator around which the drive coil is wound is a magnet having a low magnetic permeability, and is maximum when the yoke portion has a high magnetic permeability. Is used to generate a position detection signal that represents the rotational position of the magnet and yoke part on the rotor surface and the rotational position of the magnetic pole that is uniquely determined from the rotational position of the rotor and the magnet that represents the measured or detected inductance of each drive coil. And means for continuing driving during rotation based on the generated position detection signal. That.

  Alternatively, the above-described means for driving at the start based on the position detection signal generated from the one representing the inductance of each drive coil measured or detected during the stop, in the drive device for the sensorless synchronous motor described above And each means for continuing the driving during rotation based on the position detection signal generated from the one representing the inductance of each driving coil measured or detected during the rotation after driving at the start. It is characterized by having.

  Alternatively, in the sensorless synchronous motor driving apparatus described above, the means for measuring or detecting the one representing the inductance of each of the driving coils flows a pulse current through the two-phase driving coils of the three-phase driving coils, and remains. It is characterized in that a voltage induced in accordance with the mutual inductance is detected in the drive coil of the other phase.

  According to the above configuration of the present invention, in the rotor structure, one magnetic pole is exposed as a magnet on the rotor surface, and the other magnetic pole adjacent to the rotor is formed by the yoke portion, so that a rotational force is generated. The first effect is that the magnetic flux can be effectively used, the saliency is also provided, and even if the synchronous motor is miniaturized, a high-efficiency output and a stable starting torque can be obtained and machining is easy. Is obtained.

  Also, since one of the magnetic poles is a magnet and the other magnetic pole is a yoke part, the difference in inductance of the drive coil between them is large, and the measurement or detection result of the inductance shows a good S / N ratio, The processing is easy, high detection accuracy is obtained, and the value of the position detection signal generated from what represents the inductance indicates whether the magnetic pole opposed to the stator is a magnet or a yoke part. Or S pole, which represents the inductance in a predetermined cycle, is measured or detected, so a position detection signal equivalent to that of the position sensor can be obtained, and the rotational position of the rotor can be easily set not only during rotation but also during start-up The second effect is that the starting characteristic and the controllability during rotation can be improved.

The present invention has a structure in which a highly efficient output and a stable starting torque can be obtained even when it is downsized, and the rotational position of the rotor can be easily detected not only at the time of rotation but also at the time of starting. An object of the present invention is to provide a sensorless synchronous motor capable of improving controllability and a method and apparatus for driving the same. In the structure of a rotor, one magnetic pole is exposed as a magnet on the rotor surface, and the other magnetic pole adjacent thereto is a yoke. Forming a section, enabling effective use of magnetic flux for generating rotational force, and having a structure having saliency, and the magnetic permeability of the magnetic pole of the rotor facing this sensorless synchronous motor depending on the rotational position Varies greatly depending on whether the magnet is a magnet of one magnetic pole or the yoke part of the other magnetic pole, thereby changing the inductance of the opposing stator. From the voltage corresponding to the inductance of each drive coil detected by passing a detection current through the stator drive coil using the fact that the N pole or S pole is uniquely determined by the magnet or yoke part. A position detection signal indicating whether the rotor surface facing the stator is N pole or S pole or the position of the magnetic pole according to the ratio is generated, and driving and rotation at the start are performed based on the generated magnetic pole position detection signal Realized by performing one or both of the driving at the time.
Embodiments of the present invention will be described below with reference to the drawings. The description will be made specifically with reference to examples.

  FIG. 1 is a configuration diagram viewed from a cross section of a sensorless synchronous motor according to a first embodiment of the present invention. In this embodiment, an example of a three-phase driven two-pole rotor will be described for the sake of simplicity. The sensorless synchronous motor 1 according to the present embodiment includes fixed-side stators 2u, 2v, and 2w (hereinafter referred to as “2” in the representative case) and a rotor 3 that rotates about a rotating shaft 4. The present invention is characterized by the structure of the magnetic poles of the rotor 3.

  First, the configuration of the stator 2 will be described. The stator 2 is disposed so as to maintain a narrow gap with the peripheral surface of the rotor 3 and to divide the peripheral surface into three parts. The stators 2u, 2v, and 2w are integrated by a yoke portion 5 that covers the entire motor, and each phase drive coil 6u, 6v, and 6w (hereinafter referred to as 6 is represented) is wound. It has been. Next, the configuration of the rotor 3 will be described. In the rotor 3, one magnetic pole (N pole in the illustrated example) of the magnet 7 is exposed on one half circumference of the peripheral surface, and the other half circumference is formed by the yoke portion 8 of the rotor 3. The other magnetic pole (S pole in the illustrated example) of the magnet 7 is in contact with the yoke portion 8 inside the rotor 3. For this reason, the other half-circumferential surface formed by the yoke portion 8 of the rotor 3 is the S pole. That is, the surface of the magnet 7 is uniquely determined such that the surface is an N pole and the surface of the yoke portion 8 is an S pole. In the motor of the present invention, since the magnet on the rotor surface is reduced by half compared to a normal motor, the torque is also reduced. In order to compensate for this, the thickness of the magnet may be increased by about twice.

  The operation when the sensorless synchronous motor configured as described above is stopped will be described. The magnetic permeability μ is μ≈1 for the magnet and μ≈5000 for the yoke portion. Therefore, when the circumferential surface of the rotor 3 facing the stator 2 is the magnet 7, the permeability μ is small, so that the inductance of the drive coil 6 is minimized. Inductance is maximized. By utilizing this difference, even when the stator 2 is excited with a small current and the inductance is detected, the magnetic poles of the rotor 3 on the opposing surfaces of the stators 2u, 2v, 2w of each phase can be detected with a large S / N ratio. Can do. That is, in the case of the illustrated example, if the inductance of the drive coil 6 is minimum, it can be determined as the N pole on the magnet 7 side, and if the inductance of the drive coil 6 is maximum, it can be determined as the S pole on the yoke portion 8 side. . Moreover, if it is an intermediate value, the ratio of the N pole and the S pole can be known from the magnitude.

  In addition, the magnetic flux emitted from the magnet 7 exits from the magnetic pole on the surface (N pole in the illustrated example), passes through the peripheral surface of the rotor 3, and reaches the magnetic pole on the surface of the yoke portion 8 (S pole in the illustrated example). Unlike the salient pole structure, the magnetic flux on the surface side is not short-circuited in the rotor. For this reason, when this magnetic flux can be effectively used as a magnetic flux for obtaining a rotational force, and the motor 1 is small, the gap between the stator 2 and the rotor 3 cannot be reduced in proportion to the dimensions of the motor. However, a synchronous motor with high efficiency can be obtained. The effect of obtaining a synchronous motor with a high efficiency can be obtained regardless of the size of the motor.

  The above embodiment is an example of a synchronous motor having a two-pole structure by three-phase driving. FIG. 2A is a cross-sectional view showing an embodiment of a sensorless synchronous motor having a four-pole structure by three-phase driving according to the present invention, and FIG. 2B is a six-pole structure by three-phase driving according to the present invention. FIG. 2 (c) is a structural view seen from a cross section showing an embodiment of a sensorless synchronous motor having a three-phase drive according to the present invention. .

  In the case of three-phase driving, the ratio of the number of rotor poles to the number of slots in the stator is generally a ratio of 2 to 3, or a ratio of 2 to 6, similar to the embodiment of the rotor having the above-described two-pole structure. The example shows a case of a ratio of 2 to 3, where the number of stator slots is 6 when the number of rotor poles is 4, the number of stator slots is 9 when the number of rotor poles is 6, and the number of rotor poles is In the case of 8, the number of stator slots is 12. In the configuration of the rotor, the magnet 7 constituting one magnetic pole (N pole in the illustrated example) is exposed on the surface of 1 / n (n is the number of poles) of the peripheral surface, and 1 / n of the adjacent peripheral surface is set to the rotor 3. The yoke part 8 is used, and a rotor having n poles is formed by repeating this pair. Since the other magnetic pole (S pole in the example) of the magnet 7 is in contact with the yoke portion 8 inside the rotor 3, the 1 / n circumferential surface formed by the yoke portion 8 of the rotor 3 is the S pole. Become. That is, as in the first embodiment, the surface of the magnet 7 is uniquely determined such that the surface of the magnet 7 is N-pole and the surface of the yoke portion 8 is S-pole. The operation of this embodiment is the same as that of the first embodiment and can be easily inferred, so that the description thereof is omitted.

  FIG. 3 is a block diagram showing an electrical configuration of a sensorless synchronous motor driving apparatus according to a third embodiment of the present invention. In this embodiment, a three-phase driving example will be described. A sensorless synchronous motor (hereinafter simply abbreviated as a motor) 1 to be controlled by the drive device of this embodiment is the motor described in the first and second embodiments, and a magnet with one magnetic pole exposed. 7 and a rotor 3 constituted by a yoke portion 8 on which the other magnetic pole is formed, and a stator 2 wound with drive coils 6u, 6v, 6w.

  As an example, the drive device includes a control unit 11, an inverter unit 12, a position detection signal generation unit 13, an A / D conversion unit 14, and position detection resistors Ru, Rv, and Rw. The control unit 11 includes a microcomputer and a memory for storing a program and data thereof, and the like, and includes a speed command function unit 11a, a speed control function unit 11b, a PWM control function unit 11c, a position / speed detection function unit 11d, and an output switching unit. It has function means 11e. These functional means are realized by a program, but a part or all of them may be configured by hardware.

  The inverter unit 12 is composed of a series-parallel circuit of switching elements Qu1, Qv1, Qw1 such as transistors and switching elements Qu2, Qv2, Qw2 such as transistors, and each series connection point is, for example, star-connected. Connected to each of the drive coils 6u, 6v, 6w of the motor 1. Each switching element constituting the inverter unit 12 is turned on by the PWM control function unit 11c of the control unit 11 during normal rotation control and by the position / speed detection function unit 11d during inductance measurement of the drive coils 6u, 6v, 6w. / Off controlled. The output switching function unit 11e switches whether the output to the inverter unit 12 is output from the PWM control function unit 11c or the position / speed detection function unit 11d according to a command from the position / speed detection function unit 11d. In this example, the configuration is such that PWM driving is performed, but it may be configured to perform PAM driving or sine wave driving of existing technology.

  The position / speed detection function unit 11d of the control unit 11 is activated by the speed command function unit 11a, and a pulse current for measuring the inductance of each drive coil 6u, 6v, 6w at a predetermined period, for example, every several ms. In order to flow, the inverter unit 12 is controlled. The position / speed detection function means 11d first instructs the output switching function means 11e to switch the output to the inverter unit 12 to the position / speed detection function means 11d side. Next, the switching element (for example, Qu1 and Qv2) of the inverter unit 12 is controlled to be turned on, and one to several pulse currents (for example, about 10 kHz) are applied to the two-phase drive coils (for example, 6u, 6v). The detection voltage of another phase driving coil (for example, 6w) is obtained. This is sequentially performed for the remaining drive coils, and the detection voltages of the three drive coils 6u, 6v, 6w are obtained. After the flow of the pulse current, the output switching function means 11e is commanded to return the output to the inverter unit 12 to the PWM control function means 11c side. The detection voltage described above is a value corresponding to the mutual inductance, and the value of the mutual inductance depends on the ratio of the types of magnetic poles on the surface of the opposing rotor (which is uniquely determined by the magnetic pole of the magnet 7 or the magnetic pole of the yoke portion 8). Therefore, the detection voltages of the three drive coils 6u, 6v, and 6w represent position detection signals.

  The resistors Ru, Rv, and Rw are connected between the connection lines of the inverter unit 12 and the drive coils 6u, 6v, and 6w of the respective phases and the ground, and the connection line sides are connected to the position detection signal generation unit 13. The resistance values of the resistors Ru, Rv, and Rw are set to high resistances that do not affect normal driving. The position detection signal generation unit 13 includes a high-pass filter, a peak hold circuit, an integration circuit, and the like, and cuts off a voltage of about several hundred Hz induced by rotation control by PWM from the voltage detected by the resistors Ru, Rv, and Rw. Only the detection voltage of about 10 kHz, for example, induced in response to the pulse current passed to measure the inductance by the position / speed detection function means 11d is passed, and this detection voltage is smoothly passed through the peak hold circuit, the integration circuit, etc. Next, a position detection signal that is continuous is generated. The A / D converter 14 converts the generated analog position detection signal into a digital value and inputs it to the position / velocity detection function means 11d. The position / speed detection function unit 11d creates rotational position information based on the input position detection signal and calculates the rotational speed based on the period of the position detection signal.

  When receiving a speed command from the outside, the speed command function means 11a of the control unit 11 activates the position / speed detection function means 11d, and the motor 1 calculated by the speed command from the outside and the position / speed detection function means 11d. And the error signal is passed to the speed control function means 11b. The speed control function unit 11b adds an error signal to the magnitude of the current speed signal, and determines the timing of inversion of the speed signal of each phase based on the rotational position information created by the position / speed detection function unit 11d. To the PWM control function means 11c. The PWM control function unit 11c performs pulse width modulation on the magnitude of the speed signal and reverses the polarity at the instructed timing, while switching elements Qu1, Qv1, Qw1 and switching elements Qu2, Qv2, Qw2 constituting the inverter unit 12. Control on / off of. Thereby, each phase current of the three phases flows through the drive coils 6u, 6v, 6w of each phase of the stator to generate a rotating magnetic field, and the rotor 2 rotates. When the error signal becomes large, such as when starting or stopping, or when the load fluctuates, the speed signal may be gradually changed to avoid sudden changes in the rotational speed. In this example, forward rotation control is assumed, but forward and reverse rotation control is also possible. In this case, control is performed by adding a sign corresponding to forward / reverse rotation to a control value that requires explicit direction.

  An operation example and an operation of the embodiment having the above configuration will be described. FIG. 3 is a flowchart for explaining the operation example, and s1 to s14 represent steps.

  First, assume that a speed command is received from the outside when the motor 1 is in a stopped state (s1). First, the speed command function means 11a of the control unit 11 is activated, and this speed command function means 11a activates the position / speed detection function means 11d (s2). The position / speed detection function unit 11d switches the output of the output switching function unit 11e to the inverter unit 12 to the position / speed detection function unit 11d side (s3), and controls the switching element of the inverter unit 12 to control two phases. A pulse current is passed through the drive coil, and a detection voltage corresponding to the mutual inductance is obtained from the drive coil of the other phase for all the drive coils 6u, 6v, 6w (s4), and the inverter of the output switching function means 11e The output to the unit 12 is returned to the PWM control function means 11c side (s5), and the position detection signal of each phase is obtained through the position signal generation unit 13 and the A / D conversion unit 14 (s6). The position / velocity detection function means 11d creates rotational position information based on the position detection signal (s7) and calculates a speed based on the period of the position detection signal (s8).

  Next, the speed command function means 11a compares this calculated speed with an external speed command to create an error signal (s9). Here, if the calculated speed is “0” and the error signal is also “0” (s10), it is determined that the motor 1 has stopped, and each functional unit is stopped (s11), and the process ends. If it is not a stop state (s10), the speed control function means 11b determines and instructs the speed signal of each phase and the timing of inversion based on the error signal and the rotational position information (s12). The PWM control function unit 11c performs PWM control of the inverter unit 12 so as to perform pulse width modulation on the magnitude of the instructed speed signal and to reverse the polarity at the instructed timing (s13). As a result, the synchronous motor 1 starts or continues to rotate.

  Next, it is determined whether or not a predetermined cycle has been reached. If it has not been reached (s14), the position detection signal acquisition (s6) to PWM control (s13) are repeatedly executed. If it has reached (s14), the process from the position detection process (s3 to s5) to the PWM control (s13) is executed.

  As described above, in this embodiment, from the start of the motor to the normal speed control and stop can be performed with an extremely simple algorithm, the control unit does not need to have high processing capacity at high speed, and is inexpensive. It can be composed of a single microcomputer. If there is a margin in the processing capacity of the microcomputer constituting the control unit 11, the detection voltage at the resistor is A / D converted and input to the control unit as it is, and by the high-pass filter processing and envelope processing by the program in the control unit, It is also possible to generate a position detection signal.

  In this embodiment, the position detection signal is generated from the detection voltage. However, since the detection voltage changes according to the mutual inductance value, the position detection signal is generated from the inductance value. . The mutual inductance value changes according to the magnitude of the magnetic permeability. Therefore, if the magnetic pole on the rotor surface is a magnet, the magnetic permeability is as small as about 1, and if the magnetic pole is a yoke portion, the magnetic permeability is Large because it is as large as about 5000. Therefore, the S / N ratio is large, signal processing is easy, and high detection accuracy can be obtained. The detection voltage is minimized when the magnetic pole of the magnet is brought close to the center of the stator, and the detection voltage is maximized when the magnetic pole of the yoke is brought closer. Here, since the magnetic pole of the magnet and the magnetic pole of the yoke part are uniquely determined, the detection voltage represents a position detection signal, and is a sensorless but position detection signal equivalent to the case where a position sensor is provided. Is obtained.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to the present embodiment, and the present invention can be changed even if there is a design change or the like without departing from the gist of the present invention. include. For example, although the above embodiment has been described on the assumption that it is applied to a small sensorless synchronous motor, the present invention can be similarly applied to a large sensorless synchronous motor. When a large sensorless synchronous motor is rotated at a high speed, it is preferable to cover a protective tube in order to prevent the magnet from falling off the rotor surface. Further, the sensorless drive control is not limited to the three-phase control in the above embodiment, and may be other multiphase control. In this case, the number of stator slots is changed in accordance with the control. The speed control function of the control unit is not limited to the embodiment, and current vector control, observer control, and the like of the existing technology may be performed. However, depending on the existing control method, a current sensor, a tachometer, or the like may be required.

  The present invention can be suitably used not only for a small sensorless synchronous motor but also for a conventional large sensorless synchronous motor.

BRIEF DESCRIPTION OF THE DRAWINGS It is the block diagram seen from the cross section of the sensorless synchronous motor which is the 1st Example of this invention. It is the block diagram seen from the cross section of the sensorless synchronous motor which is 2nd Example of this invention, Comprising: (a) is a block diagram which shows the Example of the sensorless synchronous motor of the 4 pole structure by 3 phase drive, (b) ) Is a configuration diagram showing an embodiment of a sensorless synchronous motor having a six-pole structure by three-phase driving, and (c) is a configuration diagram showing an embodiment of a sensorless synchronous motor having an eight-pole structure by three-phase driving. It is a block diagram which shows the electric constitution of the drive device of the sensorless synchronous motor which is the 3rd Example of this invention. It is a flowchart explaining the operation example of the drive device of the sensorless synchronous motor of the 3rd Example. It is a figure which shows the structural example of the conventional sensorless synchronous motor, Comprising: (a) is a case of a SPM type sensorless synchronous motor, (b) is a case of an IPM type sensorless synchronous motor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Sensorless synchronous motor 2u, 2v, 2w ... Stator 3 ... Rotor 4 ... Rotating shaft 5 ... Yoke part 6u, 6v, 6w ... Drive coil 7 ... Magnet 8 ... Yoke part 11 ... Control part 12 ... Inverter part 13 ... Position detection Signal generator 14 ... A / D converter Ru, Rv, Rw ... resistance

Claims (9)

  On the rotor surface facing the stator, an N pole formed by a magnet as one magnetic pole and one magnetic pole of the S pole are arranged, and on the rotor surface adjacent to this one magnetic pole, an N pole formed by a yoke portion and A sensorless synchronous motor, wherein the other magnetic pole of the S poles is arranged.   One of the N and S poles formed by a magnet that is the one magnetic pole, and the other of the N and S poles formed by a yoke portion that is a magnetic pole adjacent to the one magnetic pole, The sensorless synchronous motor according to claim 1, wherein a rotor having a multipolar structure is configured as a pair.   A driving method for the sensorless synchronous motor according to claim 1 or 2, wherein a value representing the inductance of each driving coil being stopped is measured or detected, and the value representing the inductance is wound around the driving coil. From what represents the inductance of each of the measured or detected drive coils by utilizing the fact that the rotor surface facing the stator is minimum when the magnet has a low magnetic permeability and maximum when the rotor has a high magnetic permeability. A position detection signal representing the stop position of the magnet and yoke on the rotor surface and the stop position of the magnetic pole uniquely determined from these stop positions is generated, and driving at the start is performed based on the generated position detection signal A method for driving a sensorless synchronous motor.   A driving method for the sensorless synchronous motor according to claim 1 or 2, wherein the rotating drive is interrupted at regular intervals to measure or detect a value representing the inductance of each driving coil, and represents the inductance. Using the fact that the value of the object is minimized when the rotor surface facing the stator around which the drive coil is wound is a magnet with a low permeability, and maximized when the yoke part has a high permeability, the measurement or detection is performed. From the representation of the inductance of each drive coil, a position detection signal that represents the rotational position of the magnet and yoke on the rotor surface and the rotational position of the magnetic pole that is uniquely determined from these rotational positions is generated, and this generated position detection signal A driving method of a sensorless synchronous motor, characterized in that the driving during rotation is continued based on the above.   According to the driving method of the sensorless synchronous motor according to claim 3, after driving at the start based on the position detection signal generated from the one representing the inductance of each driving coil measured or detected during the stop, According to the sensorless synchronous motor driving method described above, the rotation of the sensorless synchronous motor is continued based on the position detection signal generated from the one representing the inductance of each drive coil measured or detected during the rotation. Driving method.   A drive device for the sensorless synchronous motor according to claim 1 or 2, wherein means for measuring or detecting the inductance representing the inductance of each driving coil, and the inductance representing the inductance are provided on a stator wound with the driving coil. Using the fact that the opposing rotor surface is the minimum when the magnet has a low permeability and the maximum when the yoke part has a high permeability, the rotor surface is represented by the inductance of each measured or detected drive coil. Means for generating a position detection signal indicating the rotation position of the magnet and the yoke portion and the rotation position of the magnetic pole uniquely determined from these rotation positions, and means for driving at the start based on the generated position detection signal; A sensorless synchronous motor drive device characterized by comprising:   A drive device for the sensorless synchronous motor according to claim 1 or 2, wherein the drive during rotation is interrupted at regular time intervals, and means for measuring or detecting the one representing the inductance of each drive coil; and Utilizing the fact that the inductance represents the minimum when the rotor surface facing the stator around which the drive coil is wound is a magnet having a low magnetic permeability and the maximum when the rotor surface is a yoke portion having a high magnetic permeability. Means for generating a position detection signal indicating the rotation position of the magnet and yoke portion on the rotor surface and the rotation position of the magnetic pole uniquely determined from these rotation positions from the detected inductance of each drive coil, and the generated position A drive device for a sensorless synchronous motor, characterized by comprising means for continuing driving during rotation based on a detection signal.   In the sensorless synchronous motor drive device according to claim 6, each means for performing driving at the start based on a position detection signal generated from what represents the inductance of each drive coil measured or detected during the stop, 8. The sensorless synchronous motor driving device according to claim 7, wherein after driving at start-up, the sensorless synchronous motor is rotating based on a position detection signal generated from a value representing an inductance of each driving coil measured or detected during the rotation. A drive unit for a sensorless synchronous motor, characterized by comprising: each means for continuing driving.   Means for measuring or detecting what represents the inductance of each of the drive coils is induced in the remaining phase drive coils according to the mutual inductance by passing a pulse current through the two-phase drive coils of the three-phase drive coils. The sensorless synchronous motor drive device according to any one of claims 6 to 8, wherein the voltage is detected.

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