JP5257661B2 - Synchronous motor control method and control apparatus - Google Patents

Description

  The present invention relates to a method for starting a synchronous motor that is composed of a salient pole or reverse salient pole type rotor and is not provided with a sensor for detecting the rotational position of the rotor, and in particular, a synchronous motor having a rotor rotational positioning mode and a synchronous operation mode. The present invention relates to a motor control method and a synchronous motor control device including the control method.

As a method for starting a synchronous motor that does not have a position sensor for detecting the rotational position of a conventional rotor, there is one described in Patent Document 1. When operating a synchronous motor without a position sensor, the rotational position of the rotor is detected from the terminal voltage of the armature winding (stator coil), and the inverter is controlled based on the detection signal to perform steady operation. Since no induced voltage is generated in the winding, a low-frequency synchronous start-up operation mode is provided in which the rotational speed of the rotor is increased by using an inverter as the other control system prior to steady operation. In the starting method for starting a synchronous motor without a rotor position sensor described in Patent Document 1, the current flowing path to the armature winding is fixed to an arbitrary one before entering the low-frequency synchronous starting operation mode. This is a start-up method in which a low-frequency synchronous start-up operation is performed after a current is passed, a current is gradually increased from 0, a positioning mode period is set in which the rotor is moved to a position where no rotational torque is generated and fixed.
Japanese Patent No. 2533472

  However, the positioning method of the starting method has the following problems.

  (A) In the positioning mode, when the initial position of the rotor is near 180 degrees with respect to the energization position phase in which the armature winding is energized to position the rotor, the direct current flowing through the armature winding is increased. However, since no rotational torque is generated in the rotor (rotational torque = 0), positioning for moving and fixing the rotor cannot be performed.

  (B) If the rotor cannot be positioned and the rotor is rotated by further increasing the direct current flowing through the armature winding in the state of (a), the rotor will rotate rapidly.

  (C) When the rotor suddenly rotates, the synchronous motor becomes a generator, an abnormal voltage is generated, an overcurrent flows, and the system is stopped.

  The present invention has been made in view of the above problems. Therefore, in a synchronous motor that has a salient pole or reverse salient pole type rotor and is operated without a position detection sensor, and in which a positioning mode and a synchronous operation mode are set as start control, the initial position of the rotor Control method for synchronous motor and control method for preventing overcurrent due to sudden rotation of rotor depending on initial position of rotor and preventing system stoppage depending on initial position of rotor It is an object to provide a synchronous motor provided with

(1) In order to solve the above-described problem, a synchronous motor control method according to the present invention includes a salient pole or reverse salient pole type rotor and a stator coil, and a position detection sensorless synchronization that detects the rotational position of the rotor. A control method for driving a motor, wherein the synchronous motor is driven by an inverter that is energized by applying a predetermined voltage to the stator coil. In addition, in order to estimate the initial position of the rotor that is stopped, at least two pulse energizations consisting of a first pulse and a second pulse whose pulse energization phase difference is within 90 degrees is applied to the stator coil. And detecting the current value associated with each of the pulse energization, and determining the initial position region of the rotor based on the two detected current values. Be those, wherein upon startup, the positioning energized phase so as to avoid a state in which the magnetic poles of the magnetic poles and the stator of the rotor can not directly facing the positioning on the basis of the determined initial location area of the rotor was is determined It is characterized by.

  That is, the synchronous motor control method of the present invention performs at least two pulse energizations with different energization phases on the stator coil before the positioning mode set as the initial start control, and the magnitude of the current value. Thus, the initial position of the rotor is estimated. The inductance of the salient pole or reverse salient pole type rotor has a salient pole or reverse salient polarity in the inductance depending on the magnet position of the rotor, and the inductance increases or decreases every 90 degrees in electrical angle. Here, as shown in FIG. 6A, if the N-pole direction of the rotor is defined as the d-axis, and the direction advanced 90 degrees from the d-axis is defined as the q-axis, the inductance is minimum on the d-axis and maximum on the q-axis. Become. The current flowing through the stator coil is easy to flow when the inductance is small, and difficult to flow when the inductance is large. Therefore, as shown in FIG. 5B, when the direction of the d-axis and the magnetic pole of the stator coincides (θ = 0), the current flowing through the stator coil becomes maximum, and the direction of the magnetic pole of the d-axis and the stator is 90 degrees. When (θ = 90), the current flowing through the stator coil is minimized. Thus, the current flowing through the stator coil varies depending on the position where the rotor is stopped. Using the characteristics of the salient pole or reverse salient pole type rotor, two pulse energizations having a phase difference are performed, and the current position at that time is compared to determine the initial position region of the rotor. Since the applied voltage is a pulse voltage with a slight time width, there is no possibility of rotating the stopped rotor or generating noise.

In particular, the synchronous motor control method of the present invention includes a control method for avoiding a state in which a positioning energization phase is determined based on the determined initial position region of the rotor at the time of startup, and the rotor cannot be positioned in a straight line. It is a thing .

  When the positioning energization phase is far away from the initial position of the rotor, the current flowing in the stator coil for positioning the rotor is increased. When the magnetic pole of the rotor and the magnetic pole of the stator coil are directly opposed (for example, the N pole of the rotor and the N pole of the stator coil are opposed), or the rotor magnetic pole and the magnetic pole of the stator coil are in a state close to the direct facing In some cases, the rotor rotates rapidly. In (1), when the initial position region of the rotor is determined, the energization phase of the current flowing through the stator coil for positioning can be set to an energization phase in a range where the rotor does not rotate rapidly. Furthermore, by preventing the rotor from rotating suddenly, it is possible to suppress the rotor from rotating suddenly and causing an overcurrent to cause a system stop.

( 2 ) Further, preferably, in the synchronous motor control method of (1), the pulse interval between the first pulse and the second pulse may be greater than or equal to the stator coil time constant.
By setting the pulse interval between the two pulses to be equal to or greater than the stator coil time constant, there is an effect of attenuating the current flowing by applying the first pulse and ensuring measurement accuracy.

( 3 ) Further preferably, also in the method for controlling a synchronous motor of (1) or (2) , before the positioning mode, the third pulse having an electrical angle of 180 degrees with respect to the second pulse is further provided. The magnetic pole polarity of the rotor may be determined.

  According to this configuration, the magnetic pole discrimination of the rotor (N pole / S pole discrimination) can be performed using the magnetic saturation of the field magnet. When the direction of the magnetic flux generated by the pulse current is the same as the field magnetic flux, magnetic saturation occurs. Since the inductance is reduced by magnetic saturation, the pulse current easily flows. On the contrary, when the direction of the magnetic flux generated by the pulse current is opposite to the field magnetic flux, the magnetic flux generated by the pulse current and the field magnetic flux cancel each other, so that magnetic saturation does not occur. If the magnetic saturation does not occur, the inductance increases, and the pulse current is less likely to flow. Utilizing this characteristic, the present invention is configured to determine the magnetic pole of the rotor by comparing the current values of the second pulse and the third pulse. Furthermore, with this configuration, the rotation angle at the time of positioning of the rotor can be suppressed to a maximum of 90 degrees, and by suppressing the rotation angle to within 90 degrees, an overcurrent can be generated more reliably due to a rapid rotation of the rotor, as will be described later.

( 4 ) The invention described in claims 4 and 5 is an invention of a control apparatus for a synchronous motor. The operation and effect thereof is the same as that of the control method for a synchronous motor described in the above (1) to ( 3 ). Since it is the same as that of the effect | action and effect of invention, description is abbreviate | omitted.

  According to the present invention, control of a synchronous motor that includes a salient pole or reverse salient pole type rotor and that is operated without a position detection sensor, and in which a positioning mode and a synchronous operation mode are set as start control. In this method, a state where positioning cannot be performed regardless of the initial position of the stopped rotor is avoided, and furthermore, depending on the initial position of the rotor, an excessive current may be generated due to a sudden rotation of the rotor, resulting in a system stoppage. However, there is an effect of preventing the occurrence of such an overcurrent and the system stop due to the overcurrent. Moreover, the control apparatus of the synchronous motor provided with the control method can be provided.

  Hereinafter, embodiments of the present invention will be described in more detail.

<Embodiment>
FIG. 1 is a block diagram showing the overall configuration of a synchronous motor control system according to an embodiment of the present invention. As shown in FIG. 1, a synchronous motor control system 20 includes a synchronous motor 1 having a three-phase stator coil 1a and salient pole or reverse salient pole type rotor 1b, and a control device 2 for controlling the synchronous motor 1. The control unit 2 includes a battery 3 that supplies DC power, and an ECU (electronic control unit) 50 that transmits and receives information related to the start command of the synchronous motor 1 between the control unit 2 and the like. The control device 2 is connected to an inverter 4 for driving the synchronous motor 1, a drive circuit 5 for controlling on / off of the IGBTs (T 1 to T 6) constituting the inverter 4, and a lower stage of each phase arm of the inverter 4. Current value detecting means 6 constituted by the resistors R1, R2 and R3, an overcurrent detector 7 for detecting an overcurrent of the synchronous motor 1, and a microcomputer (hereinafter referred to as a microcomputer) 8. ing. The synchronous motor 1 is an interior permanent magnet synchronous motor (IPMSM). C1 and C2 are bypass capacitors provided in the battery 3 and the inverter 4, respectively.

  The drive circuit 5 is controlled by the microcomputer 8, and the output of the current value detection means 6 is input to the rotor initial position area determination unit 81 of the microcomputer 8 via the amplifiers A 1, A 2, A 3. The rotor initial position area determination unit 81 corresponds to the rotor initial position area determination means of the present invention. The output of the overcurrent detector 7 is input to the microcomputer 8 via the amplifier A4. Here, the microcomputer 8, the inverter 4, the current value detecting means 6, and the rotor initial position region discriminating unit 81 are included in the rotor initial starting means of the present invention. In FIG. 1, the outputs (d1 to d6) of the drive circuit 5 are connected to the gate terminals (b1 to b6) of the IGBT (T1 to T6), although not shown.

FIG. 2 shows the progress of the start-up control of the synchronous motor. Usually, the positioning operation (X), the synchronous operation (Y), and the steady operation (Z) gradually increase the rotation of the rotor and shift to the steady operation. Prior to the positioning operation mode (X), the rotor initial position region discrimination (X ₀ ) is further performed.

  Next, the rotor initial position region determination operation of this embodiment will be described based on the flowchart of FIG. The rotor initial position region discriminating means according to the present invention is a region where the rotor is suddenly rotated by positioning and an overcurrent is generated with respect to the positioning phase (θ1) set by the initial position of the stopped rotor. It is determined whether or not there is.

  First, the mechanism of overcurrent generation will be described with reference to FIGS.

As described above in the section of the prior art, in the positioning operation, a current in a certain direction (hereinafter referred to as a motor current) is applied to the stator, and torque generated at that time (hereinafter referred to as a motor generated torque) T _M Is expressed by the following equation.
T _M = Pn [−Φa · I _M · sin θ + (1/2) (Lq−Ld) (I _M ) ² · sin 2θ] (1)
Here, T _M : Motor generated torque, Pn: Number of pole pairs, Φa: Stator flux linkage by permanent magnet, I _M : Motor current, Lq: q axis inductance, Ld: d axis inductance, θ: Rotor N pole and stator This is the angle formed by the S pole.

As described above, the synchronous motor 1 of the present embodiment is an IPMSM. Motor torque T _M of the IPMSM is considered the sum torque of the magnet torque and the reluctance torque. The magnet torque is an attractive force or a repulsive force generated between the magnetic field of the stator coil and the magnetic field of the rotor magnet in the previous term of the equation (1). The reluctance torque is a force that attracts iron by the magnetic field of the stator coil in the latter term of equation (1). As can be seen from the equation (1), the motor generated torque T _M is a function of θ and is distributed in magnitude depending on the initial position of the rotor as shown in FIG. θ is an angle formed by the rotor N pole and the stator S pole as described in the equation (1) (see FIG. 6A). Further, the load torque T _L which serves to prevent rotation of the rotor, Datosuruto constant as shown in FIG. 4, the rotational torque T _R acting on the rotor is expressed by the following equation.
T _R = T _M −T _L = J (d ² θ / dt ² ) (2)
Here, J is inertia (moment of inertia).

A condition for increasing the motor current during the positioning operation will be described. The motor current I _M is expressed by the following equation.
I _M = (V + K _e ω) / r (3)
Here, V: motor coil applied voltage (stator coil applied voltage), K _e : counter electromotive constant, ω: rotor angular velocity, r: winding resistance.

In the positioning operation, in order to rotate the rotor to a predetermined position, the motor coil applied voltage (V) of formula (3) is, for example, U phase: −27 A, V / W phase in the synchronous motor of the present embodiment: Applied toward 13.5A. The overcurrent is reached when the back electromotive force K _e ω is increased and superimposed, that is, when the rotor angular velocity ω is large. Angular velocity is expressed by the following equation from the relationship between the rotational torque T _R described above.
S = ∫T _R dθ = (1/2) Jω ² (4)
Here, S: is the sum of the rotational torque _{T R.}
When formula (4) is expanded for the rotor angular velocity ω,
ω = (2S / J) ^1/2 (5)
From equation (5), the rotor angular velocity omega, which is a function of the sum S of the rotational torque T _R. That is, the rotor angular velocity ω is greater the larger the sum S of the rotational torque T _R.

Figure 5 shows the relationship between the sum S and the motor current I _M of the torque T _R of the synchronous motor 1 embodiment. As shown in the upper diagram of FIG. 5, the initial position of the rotor is at a point (theta = about ± 180 degrees), the sum S of the rotational torque T _R when moving to a position for positioning of the rotor (theta = 0 degrees) Is the area (T _M −T _L ) indicated by the oblique lines. Below in Figure 5, the positioning position of the rotor from any initial position when moving up (theta = 0 degrees), shows the magnitude of the motor current I _M (where rotor initial position +135 ° ~ ± Only the range from 180 degrees to -135 degrees is shown). The horizontal axis represents the rotor initial position, and the vertical axis represents the magnitude of the motor current I _M flowing through the movement of the positioning of the rotor.

In this embodiment, the motor current I _M from the current capacity of the IGBT is configured to operate at 30A or less. Accordingly, as shown in FIG. 5 below, if the flowing motor current I _M is 30A or more, it is set overcurrent protection level in 30A to determine an overcurrent. The range leading to the overcurrent is the case where the rotor initial position is 150 degrees or more (rotor rotation angle is 150 degrees or more) as shown in FIG. 5 based on the expressions (4) and (5).

  Next, returning to the flowchart of FIG.

  In order to estimate the initial position region of the rotor, in step 1 (hereinafter referred to as S1; the same applies to other steps), first, the rotor positioning energization phase (referred to as θ1) is determined. Next, in S2, two energization pulses (voltage vectors) sandwiching θ1 are determined. The two energized pulses correspond to the first pulse and the second pulse of the present invention. At this time, the phase difference between the two energized pulses is within 90 degrees. The reason why the phase difference between the two energization pulses is within 90 degrees is that the method of estimating the initial position region of the rotor, which will be described later, is based on the current value of the current flowing by the two energization pulses. The increase / decrease is to use the characteristics that are reversed every 90 degrees as described above with reference to FIG. Here, the voltages of the two energization pulses are V1 and V2. Next, in S3, a voltage V1 pulse is applied, whereby the current flowing through the stator coil is set to I1, and the current value is detected by the current detection means 6 in FIG. Next, a voltage V2 pulse is applied in S4, whereby the current flowing through the stator coil is set to I2, and the current value is detected by the current detection means 6.

  The operations of S1 to S4 will be described with reference to specific numerical values in FIG. As shown in FIG. 7A, two energization pulses (voltage vectors V1 and V2) are set for the determined positioning energization phase θ1. In the case of FIG. 7 (a), the interval between the two energized pulses across θ1 is 30 degrees (<90 degrees). FIG. 7B shows the on / off control of the IGBT of the inverter 4 for applying the voltage V1 pulse and the voltage V2 pulse and detecting the currents I1 and I2. As shown in FIG. 7B, when the voltage V1 pulse is applied, T2 and T4 of the IGBT are turned on, and the other IGBTs are turned off. When the voltage V2 pulse is applied, T3 and T4 of the IGBT are turned on, and the other IGBTs are turned off. Thereby, the phase difference between the voltage V1 pulse and the voltage V2 pulse is 30 degrees.

  Next, the pulse width of the voltage V1 pulse and the voltage V2 pulse and the interval between the two pulses will be described with reference to FIG.

  The energization pulse needs to be short enough not to rotate the rotor. In the case of the synchronous motor of the present embodiment, the motor rotates when the current value exceeds 5A. The pulse width is 20 μs. Further, since the current value cannot be detected at 4 μs, it is set to 10 μs in this embodiment. The interval between the two pulses must be longer than the current regeneration period. In the present embodiment, as shown in FIG. 8B, the current regeneration period is 4 ms. Therefore, as shown in FIG. 8A, the pulse width is 10 μs and the pulse interval is 5 ms.

If the currents I1 and I2 are detected, next, in S5, based on the current values of the currents I1 and I2, it is determined whether the initial position where the rotor is stopped is “above the region” or “below the region” (determination 1). I do. Note that “on the area” means that the rotor is stopped at a position where the positioning position is close to the d axis (d axis ± 45 degrees), and “below the area” means that the positioning position is close to the q axis (q axis ± 45 degrees) when the rotor is stopped. Determination 1 will be described with reference to FIG.
In FIG. 9A, the horizontal axis represents the position (θ) of the rotor with respect to the positioning energization phase (0 degree) as shown in FIG. 9C. The vertical axis represents the value of current flowing through the stator when the rotor is at the position θ (when the d-axis is at the position θ).

Here, | I1 | + | I2 | ≧ α [(α / 2) = I _max + I _min : see FIG. 9A] (6)
The rotor is stopped on the area.
| I1 | + | I2 | <α (7)
When it is, it determines with the rotor having stopped under the area | region.

Following the determination of S5, a determination 2 is made as to whether or not the initial position where the rotor of S6 is stopped is near the peak value of the current (I1, I2). As shown in FIG. 9B, by comparing the difference between the current value of the current I1 and the current value of the I2 with a predetermined value β, whether the initial position of the rotor is near the peak or the current is inclined. Can be determined. That is,
|| I1 |-| I2 || <β (8)
If it is, it is determined that the initial position of the rotor is near the peak. Also,
|| I1 |-| I2 || ≧ β (9)
If it is, it is determined that the initial position of the rotor is not near the peak.

  The fact that the initial position of the rotor is in the vicinity of the peak is in the vicinity of the positioning energization phase (position where the rotor is positioned). On the other hand, if the initial position of the rotor is outside the vicinity of the peak, the rotation of the rotor by positioning is not large, so there is no possibility of overcurrent. As described above, since an overcurrent is generated when the rotor rotation angle by the rotor positioning is 150 degrees or more, the initial position of the rotor is set to 30 degrees from the positioning energization phase according to the value of | I1 |-| I2 | If β is set so that it can be determined whether it is within or less than 30 degrees, it can be determined whether or not the initial position of the rotor is in the overcurrent generation region. When the rotor rotation angle is 150 degrees or more, the positioning energization phase (positioning position) is changed so that the rotor rotation angle is within 150 degrees.

  The determination 2 will be described more specifically with reference to FIG.

  FIG. 10A shows a case where the rotor is stopped at a position of 0 degrees with respect to the positioning energization phase (positioning position). In this case, the currents I1 and I2 are in the vicinity of the peak as shown in FIG. 10B, and the rotor is stopped on the region at a substantially equal value. Therefore, the difference between the current values of the currents I1 and I2 is almost zero, which corresponds to the equation (8). Further, since the initial position (point A) of the rotor is in the overcurrent generation region, overcurrent is generated by rotation due to positioning. FIG. 10C shows an example in which overcurrent generation is avoided by changing the positioning energization phase (shifting −45 degrees) to reduce the rotation angle by positioning (decreasing to about 130 degrees).

  FIG. 11A shows a case where the rotor is stopped at a position of −45 degrees with respect to the positioning energization phase. This corresponds to the case where the rotor is stopped on the region (see Equation 6). Determination 2 is determined when the initial position of the rotor is not near the peak from the current values I1 and I2 shown in FIG. 11B (see Equation 9). Then, as indicated by an arrow in FIG. 11B, the rotation angle at which the rotor moves (rotates) from the point B at the stop position to the positioning energization phase (positioning position) is about 135 degrees, and an overcurrent is generated. There is no risk. Therefore, the positioning energization phase (θ1) is determined to be the initially set positioning energization phase (positioning position).

  When the initial position of the rotor is below the region, the rotation angle of the rotor by positioning is within 150 degrees in both cases (8) and (9), so the positioning energization phase (θ1) is There is no need to change.

  As described above, the rotor initial position area discriminating means according to the present invention determines that the initial position of the rotor is in an area where an overcurrent is generated by positioning with respect to the set positioning energization phase (θ1). It is determined whether or not there is. When it is determined that the initial position of the rotor is in a region where overcurrent occurs, the positioning energization phase is changed to a position where no overcurrent occurs.

  Next, in S8, when the rotor initial position is determined to be “on the region” in determination 1 and is determined to be “near the peak” in determination 2, and the positioning energization phase is changed, the voltage V2 pulse is further increased. A voltage V2_pulse whose phase is shifted by 180 degrees is applied, and the current flowing at that time is defined as I2_, and the current value of I2_ is detected (S10). Here, the voltage V2_pulse corresponds to the third pulse of the present invention.

  Next, as determination 3 in S11, the magnetic pole polarity (NS polarity) of the rotor is determined by comparing the current value of I2 with the current value of I2_. FIG. 12A is an actual measurement value of the relationship between the initial position of the rotor and the current value of the current that flows when the energization phase is changed. At this time, as shown in FIG. 12B, it is assumed that current values when currents I2 and I2_ are respectively supplied are detected as shown in FIG. 12A (| I2 |> | I2_ |). In this case, the current I2 is larger. That is, because I2 is increased due to magnetic saturation, the N pole of the rotor is close to the positioning energization phase (0 degrees) as shown in FIG. 12B, and therefore the positioning energization phase is θ1 set in S1. It's okay. Conversely, when | I2 | <| I2_ |, it is because the magnetic pole is not magnetically saturated by the magnetic flux due to I2_, and the NS pole of the rotor is opposite to that in FIG. Therefore, it is possible to more easily prevent overcurrent due to positioning by changing the positioning energization phase by rotating 180 degrees from θ1 set in S1. In the present embodiment, the voltage V2_pulse that is 180 degrees out of phase with respect to the voltage V2 pulse is applied as the third pulse, but the third pulse is naturally based on the voltage V1 pulse. The phase may be shifted from the V1 pulse by 180 degrees. FIG. 13 summarizes the above determinations 1 to 3 in a table.

1 is a block diagram showing the overall configuration of a synchronous motor control system according to an embodiment of the present invention. It is explanatory drawing about the rotor initial position area | region determination of embodiment of this invention. It is a flowchart about the rotor initial position area | region determination operation | movement of embodiment of this invention. It is explanatory drawing of a motor generation torque. It is explanatory drawing of the overcurrent generation mechanism in rotor positioning operation | movement. It is a figure which shows the relationship between the stop position of a rotor, and the electric current which flows through a stator coil. It is explanatory drawing of the electricity supply by a positioning electricity supply phase and voltage vector V1, V2. It is explanatory drawing about a voltage pulse. It is explanatory drawing of the determination 1 and the determination 2. FIG. It is explanatory drawing of the specific example of the determination 2. FIG. It is explanatory drawing of the specific example of the determination 2. FIG. It is explanatory drawing of the determination 3. FIG. ) It is a list of determination 1 to determination 3.

Explanation of symbols

1: Synchronous motor 2: Control device 3: Battery 4: Inverter
5: drive circuit, 6: current detection means, 7: overcurrent detector,
8: Microcomputer (microcomputer),
20: Synchronous motor control system, 50: ECU,

Claims (5)

A control method for driving a position detection sensorless synchronous motor comprising a salient pole or reverse salient pole type rotor and a stator coil, and detecting a rotational position of the rotor,
In the control method at the time of starting the synchronous motor driven by an inverter that applies a predetermined voltage to the stator coil and energizes it,
Before positioning the rotor at the time of starting, in order to estimate the initial position of the rotor that is stopped, at least a first pulse and a second pulse whose pulse conduction phase difference is within an electrical angle of 90 degrees twice the pulse energization is performed with respect to the stator coil, be those for detecting a current value associated with each of said pulsed current, to determine the initial location area of the rotor based on the size of two of the current value detected And
The synchronization energization phase is determined at the time of starting so as to avoid a state where the rotor magnetic pole and the stator magnetic pole face each other and cannot be positioned based on the determined initial position area of the rotor. Motor control method. The synchronous motor control method according to claim 1, wherein a pulse interval between the first pulse and the second pulse is greater than or equal to the stator coil time constant. After the determination of the initial position region of the rotor by energization of the first pulse and the second pulse, a third pulse having an electrical angle of 180 degrees with respect to the second pulse is further applied to the stator coil. detects a current value at the current value detection means compares the magnitude of the current value of the second pulse and the third pulse, to claim 1 or 2 for determining the magnetic pole polarity of the rotor The control method of the synchronous motor of description. A control device for driving a position detection sensorless synchronous motor that includes a salient pole or reverse salient pole type rotor and a stator coil, and detects a rotational position of the rotor,
In the control apparatus for the synchronous motor driven by an inverter that applies a predetermined voltage to the stator coil and energizes the stator coil,
Before the positioning of the rotor at the time of starting the synchronous motor, the first pulse and the second pulse whose pulse energization phase difference is within an electrical angle of 90 degrees are used to estimate the initial position of the stopped rotor. At least two pulse energizations are performed on the stator coil, and further, current value detection means for detecting a current value associated with each of the pulse energizations, and an initial value of the rotor based on the magnitudes of the two detected current values Rutotomoni a rotor initial activation means having a rotor initial location area determining means for determining the location area,
A positioning energization phase determining means for determining a positioning energization phase so as to avoid a state in which the magnetic pole of the rotor and the magnetic pole of the stator face each other and cannot be positioned based on the determined initial position area of the rotor at the time of startup; the synchronous motor control device, characterized in that the. The interval between the first pulse and the second pulse is greater than or equal to the time constant of the stator coil, and the rotor initial position region determining means further includes the second pulse after determining the initial position region of the rotor. A third pulse with an electrical angle of 180 degrees is applied to the first pulse, the current value is detected by the current value detection means, and the magnitudes of the current values of the second pulse and the third pulse are compared. The synchronous motor control device according to claim 4 , wherein the polarity of the magnetic pole of the rotor is determined.

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