JP2019000329A - Washing machine - Google Patents

Abstract

To achieve control of shifting to sensorless control by starting by smooth synchronous rotation, even without using location detection means separately, by estimating a phase at rotor stop time.SOLUTION: A washing machine includes: a pulsator for agitating laundry; a permanent magnet synchronous type motor M for driving the pulsator normally/reversely; and control means C for controlling start and stop of the motor M with respect to a rotor in a sensorless manner. The control means C includes: a short circuit brake control part 61 for performing short circuit brake when stopping; a stop phase estimation part 7 for estimating the phase where the rotor stopped from a phase current right before stop out of the phase current flowing in a coil by the short circuit brake; and a storage part 8 for storing the estimated stop phase. At the start time, the estimated rotor stop phase is retrieved from the storage part 8, and based on this, a positioning current vector which is a current vector for performing positioning of the rotor at synchronous rotation start time is generated.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a washing machine having a permanent magnet synchronous motor and capable of appropriately starting the motor.

  This type of washing machine includes a pulsator that stirs laundry, a permanent magnet synchronous motor that drives the pulsator, and a control unit that controls activation and stop of the motor with respect to the rotor without a sensor. It is customary.

  By the way, if the rotor position of the permanent magnet synchronous motor is unknown at the time of motor activation, the activation may fail.

  As means for solving the motor starting failure, for example, those disclosed in Patent Documents 1 and 2 are disclosed.

  In Patent Document 1, the rotor position detection means using a position sensor is rotated stably at the time of start-up or low-speed rotation with a large load fluctuation, and the position detection means shifts to sensorless control without using the rotor position detection means at high-speed rotation. A technique for reducing current distortion due to variation in noise and reducing noise is disclosed.

  Further, Patent Document 2 includes a rotor position detection circuit based on induced voltage detection. It is configured to detect the induced voltage during the commutation period after fixing the rotor at startup, thereby adjusting the energization pattern appropriately, increasing the motor output torque at startup, and starting up stably at high speed. .

JP 2007-175135 A

JP 2002-252996 A

  However, both of them require some kind of position detecting means for detecting the position of the rotor, and there is a problem that this causes a cost increase.

  On the other hand, in order to properly start the motor by sensorless control without using the rotor position detection means, in order to position the rotor, an appropriate current is passed through the three-phase winding to cause the rotor to be magnetized in an appropriate direction. Therefore, it is necessary to start synchronous rotation of the rotor by using a rotating magnetic field generated between the stator and the stator.

  For this purpose, the following problems must be solved. In sensorless control, the position of the rotor at the time of stopping is not known in principle. Therefore, when the attracting direction of the rotor is inappropriate, the rotor may move backward or advance, and the rotor may vibrate for a short period of time.

  FIG. 13 shows an example, and it is assumed that the rotor R constituting the permanent magnet synchronous motor M is stopped at the phase (a). In this state, when currents Iu, Iv, and Iw as shown in the figure are passed, a magnetic pole appears on the stator side, and the rotor R rotates about 90 ° by the attractive force and repulsive force of the magnet of the rotor R, and the state (b) is reached. Move. If the rotor R shifts to synchronous rotation during the rotation or vibration of the rotor R, the rotor R cannot smoothly rotate synchronously with respect to the rotating magnetic field generated between the rotor R and a step-out may occur.

  If the positioning time of the rotor R is lengthened, such a problem is less likely to occur. However, in the washing machine, the pulsator needs to be quickly reversed to obtain the cleaning power, and therefore the positioning time cannot be set long. .

  The present invention has been made paying attention to such problems, and by estimating the rotor phase when the motor is stopped and estimating the rotor position, smoothness can be achieved without using a separate rotor position detection means. The purpose is to realize a control that starts the motor with a synchronous rotation and shifts to a sensorless control.

  In order to achieve this object, the present invention takes the following measures.

  The washing machine of the present invention includes a pulsator for stirring laundry, a permanent magnet synchronous motor for driving the pulsator, and a control unit for controlling the start and stop of the motor with respect to the rotor without using a sensor. Stores the estimated phase, the short-circuit brake control unit that performs short-circuit braking at the time of stop, the stop phase estimation unit that estimates the phase at which the rotor has stopped from the phase current immediately before the stop among the phase currents that flow through the winding due to the short-circuit brake And a storage current section that extracts a rotor stop phase estimated from the storage section at the time of start-up, and generates a positioning current vector that is a current vector for positioning the rotor at the start of synchronous rotation based on the phase. To do.

  In this case, the stop phase estimator generates a short-circuit brake current vector, which is a vector of the phase current flowing in the winding by the short-circuit brake, for a plurality of sectors on stationary coordinates classified by the magnitude relation of the phase current. It is desirable to determine which sector belongs to.

  In particular, the stop phase estimator uses the determined central phase angle of the sector as the phase angle of the short-circuit brake current vector existing in the vicinity of the q-axis of the rotating coordinate system, and adds or subtracts a predetermined angle to this phase angle to obtain the phase angle of the d-axis. It is desirable to estimate.

  Alternatively, the stop phase estimation unit sets the angle obtained by adding a correction angle derived from a predetermined correspondence relationship based on the phase current to the estimated reference phase angle of the sector as the phase angle of the short-circuit brake current vector existing near the q axis. It is desirable to estimate the d-axis phase angle by adding or subtracting a predetermined angle to this phase angle.

  According to the present invention, in the reversal operation of the pulsator, the stop phase estimation unit can estimate the rotor phase at the time of stop, and the estimated phase can be stored in the storage unit. For this reason, since the position of the rotor can be known to some extent by calling the phase of the rotor from the storage unit, it is possible to reduce the product cost without providing a separate detecting means for detecting the position of the rotor. Also, by calling the rotor phase, the rotor can be positioned reliably and the rotor positioning time can be shortened, so that the motor power consumption for each inversion can be reduced.

  Further, according to the present invention, the determination of which sector the short-circuit brake current vector belongs to is made based on the magnitude relationship of the phase currents, so that the direction of the short-circuit brake current vector can be easily grasped.

  Further, according to the present invention, since the determined center phase angle of the sector is the q-axis phase angle of the rotating coordinate system, the d-axis phase angle can be estimated without any special calculation.

  In addition, according to the present invention, the angle obtained by adding a correction angle derived from a predetermined correspondence relationship based on the phase current to the estimated reference phase angle of the sector is set as the q-axis phase angle. Thus, it is possible to estimate the d-axis phase angle with higher accuracy.

  Further, according to the present invention, the phase of the rotor is extracted from the storage unit, and the positioning current vector at the start of the synchronous rotation is generated. it can.

The perspective view which shows the external appearance of the washing machine which concerns on 1st Embodiment of this invention. The longitudinal cross-sectional view which shows schematic structure of a washing machine. The circuit diagram which shows the system configuration | structure of the motor control system used as the premise structure of the phase estimation by the short circuit brake in this embodiment. The block diagram showing the function of the phase estimation by a short circuit brake, and the starting by it among the systems which concern on this embodiment. The figure which shows the relationship between a positioning current vector and a stationary coordinate system. The figure which shows the vector locus | trajectory of the short circuit brake electric current vector after applying a short circuit brake until a rotor stops. The figure which shows the relationship between the dq coordinate immediately before a stop, and a short circuit brake current vector. The figure which shows the relationship between a short circuit brake current vector and d-axis. The figure which shows the relationship between the magnitude | size of a short circuit brake current vector, and a phase. The flowchart which shows the process sequence of the phase estimation which concerns on this embodiment. The flowchart which shows a part of processing procedure of the phase estimation which concerns on 2nd Embodiment of this invention. The figure which shows the structure of the short circuit brake control part which concerns on the modification of this invention. The figure which shows the relationship between the rotor phase at the time of synchronous rotation starting, and generation | occurrence | production of a malfunction.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<First Embodiment>
FIG. 1 is a perspective view showing an appearance of a vertical washing machine (hereinafter referred to as “washing machine”) 1 according to an embodiment of the present invention. Moreover, FIG. 2 is a longitudinal cross-sectional view which shows schematic structure of the washing machine 1 of this embodiment.

  The washing machine 1 includes a washing machine body 11, an outer tub 12, a dehydrating tub (washing tub) 13, an input unit 14, a pulsator (stirring blade) 15, a drive unit 16, and a control means C (FIG. 3). Reference). Such a washing machine 1 automatically determines the amount of laundry in the dewatering tub 13 as a load amount when the input key 14 is pressed and a start key (not shown) that performs full-automatic washing is pressed. Based on this, the amount of water stored in the outer tub 12 is automatically determined in the washing step and the rinsing step, and the pulsator 15 is driven forward and reverse to perform the washing operation.

  The washing machine main body 11 has a substantially rectangular parallelepiped shape, and has an opening 11b for putting laundry (clothes) in and out of the dehydrating tub 13 and an opening / closing lid 11c capable of opening and closing the opening 11b. The laundry can be taken in and out of the dehydration tank 13 through the opening 11b by opening the opening / closing lid 11c. In addition, the input portion 14 described above is formed on the upper surface 11 a of the washing machine body 11.

  The outer tub 12 shown in FIG. 2 is a bottomed cylindrical member that is disposed inside the washing machine body 11 and can store water.

  The dewatering tub 13 as a washing tub is a bottomed cylindrical member that is disposed coaxially with the outer tub 12 inside the outer tub 12 and is rotatably supported by the outer tub 12. The dewatering tank 13 has a smaller diameter than the outer tank 12, and has a large number of water passage holes (not shown) on its wall surface 13a.

  The pulsator 15 is rotatably arranged at the center of the bottom 13b of the dehydrating tank 13, and agitates the water stored in the outer tank 12 to generate a water flow.

  The drive unit 16 includes a motor M and a clutch 16b. The motor M of this embodiment uses what is called a permanent magnet type synchronous motor (so-called “PM motor”). The motor M rotates the dehydrating tank 13 by rotating the drive shaft m that extends toward the bottom 13 a of the dehydrating tank 13. The motor M can also apply torque to the pulsator 15 by switching the clutch 16b to rotate the pulsator 15. Therefore, the washing machine 1 mainly rotates only the pulsator 15 forward and backward through a predetermined rotation ON period and rotation OFF period in the washing process and the rinsing process, and the dehydration tank 13 and the pulsator 15 are integrally and at high speed in the dehydration process. Can be rotated in one direction. The rotation speed of the pulsator 5 at the time of forward / reverse rotation is set to 900 rpm, for example.

  As described above, in order to properly start the rotor R after being stopped without a sensor, an appropriate current is applied to the three-phase winding to attract the rotor R with a magnetic force in an appropriate direction, and synchronous rotation is smoothly started. There is a need.

  Therefore, in the present embodiment, as shown in FIG. 4, the control unit C includes a short-circuit brake control unit 61 that performs a short-circuit brake at the time of stop, and a phase current that flows through the winding by the short-circuit brake. The stop phase estimation unit 7 for estimating the phase of the rotor R of the rotor and the storage unit 8 for storing the estimated phase of the rotor R at the time of stop, and the stop phase of the rotor R estimated from the storage unit 8 at the time of startup Based on this, a current vector V1 (hereinafter referred to as “positioning current vector”) for positioning the rotor R at the start of synchronous rotation is generated.

  With this configuration, in the reversing operation of the pulsator 15, the phase of the rotor R at the time of stop can be estimated and stored in the storage unit 8 without using a separate rotor position detection device. Therefore, if the stored rotor phase is used, the positioning of the rotor R at the start of synchronous rotation can be reliably performed. The rotor R can be reliably started. Further, the rotor positioning time can be shortened, and the motor power consumption for each inversion can be reduced.

  Here, the short-circuit brake is a brake in which the U / V / W winding is short-circuited by a switching element such as an IGBT, and rotational energy is converted into Joule heat of the motor winding.

  Hereinafter, the configuration of the control means C that performs sensorless control will be described first. When starting from the motor stop, the sensorless vector control is impossible because the induced voltage of the motor M is too small when the rotor is stopped or at a very low speed. For this reason, as shown in FIG. 4, the motor drive control unit 6 of the control means C is forced to rotate the rotor R to a certain speed by synchronous rotation in the synchronous rotation control unit 62, and then sensorless vector control. The unit 63 is configured to shift to vector control.

As shown in FIG. 3, the control means C includes a torque command generator 2 that generates a torque command based on a deviation between a motor rotation speed command value ω ^* _m and a motor rotation speed estimated value ω _m given as a control amount. The motor M is converted by converting the deviation between the motor current Iq (Id) during driving and the current command value Iq ^* (Id ^* ) corresponding to the torque command value T ^* into motor voltage command values V ^* q and V ^* d. A motor drive control unit 3 for driving, and a speed estimation unit that estimates a motor rotation speed ω _m using motor voltages Vq and Vd related to motor currents Iq and Id and motor voltage command values V ^* q and V ^* d. The speed estimator 4 is configured in a control loop 5. The torque command generator 2 and the motor drive controller 3 are components of an inverter controller that is generally called. Here, it is assumed that motor voltages Vq and Vd equal to the motor voltage command values V ^* q and V ^* d are generated.

The torque command generation section 2, first subtracter 21, and inputs the estimated speed value omega _m estimated from the rotational speed command omega ^* m and a motor drive state given from the microcomputer for controlling the operation in general of the washing machine 1. The difference output of the subtracter 21 is input to the speed controller 22.

Speed controller 22, to control the rotational speed of the motor M to the target value, and generates a torque command T ^* by the PI control based on the difference amount between the rotation speed command omega ^* _m and estimated speed omega _m.

The torque command T ^* generated by the torque command generation unit 22 is input to the motor drive control unit 3.

  The motor drive control unit 3 performs voltage drive while switching the switches SW1 and SW2 under the rotation coordinate system (d, q) of the magnetic poles rotating with the rotation of the rotor R of the synchronous motor M.

For switch SW2, during sensorless vector control is connected to the B side, the torque command value T ^* is a q-axis current command value Iq ^* by the gain multiplication unit 31 torque coefficient 1 / K _E multiplied, subtracted It is input to the q-axis current controller 33 via the device 32. During the synchronous rotation, the switch SW2 is connected to the A side so that Iq ^* = 0. The switch SW1 is connected to the B side at the time of sensorless vector control, and the command value Id ^* = 0 is output from the d-axis current command unit 34 and is input to the d-axis current controller 36 via the subtractor 35. . During synchronous rotation, the switch SW1 is connected to the A side so that Id ^* = a predetermined current value, for example, 3 [A]. The subtracter 32 is given a q-axis current value Iq output from the second converter 51 described later that performs [uvv → dq] conversion as a subtraction value, and the subtractor 35 receives the second value. The d-axis current value Iq output from the converter 51 is given as a subtraction value.

The q-axis current controller 33 generates the q-axis voltage command value Vq ^* by performing PI control based on the difference between the q-axis current command value Iq ^* and the q-axis current value Iq. The d-axis current controller 36 generates a d-axis voltage command value Vd ^* by performing PI control based on the difference between the d-axis current command value Id ^* and the q-axis current value Iq. And it inputs into the 1st converter 37 which performs a [dq-> uvvw] conversion in order to convert into a three-phase voltage command.

Whether to perform voltage drive control or short-circuit brake control is switched by switches SW4 and SW5. The switch SW4 is normally connected to the d-axis voltage command value Vd ^* side (AB side), but when the rotor R is stopped, it is switched to the short-circuit brake command Vd = 0 side (C side) by the short-circuit brake control. The switch SW5 is normally connected to the q-axis voltage command value Vq ^* side (AB side), but when the rotor R is stopped, it is switched to the short-circuit brake command Vq = 0 side (C side) by the short-circuit brake control.

The first converter 37 is provided with the estimated rotor rotational phase angle θe, so that q and d voltage command values Vq ^* and Vd ^* are converted into three-phase voltage command values Vu, Vv, and Vw based on the estimated rotor rotational phase angle θe. And the motor M is energized via the motor excitation circuit 38.

  On the other hand, the control loop 5 detects the phase currents Iu, Iv, and Iw through the phase current detection unit 50 provided in the motor excitation circuit 38, and performs the [uvw → dq] conversion on the second conversion. Input to the device 51. The second converter 51 converts the phase current value to q and d-axis current values Id and Iq, given the estimated rotor rotational phase angle θe. These q and d-axis current values are input to the subtracters 35 and 32, respectively.

Note that the estimated value of the rotor phase is switched by the switch SW3. The switch SW3 is connected to the B side during sensorless vector control, detects the motor current / voltage, and the speed estimator 4 estimates the motor speed. This is integrated to obtain the rotor phase θ. On the other hand, the switch SW3 is connected to the A side at the time of synchronous rotation at the initial stage of the start, and the phase θ is created by adding the integral value of the shaft speed command ω ^* _m to the integral initial value of the storage unit 8, and by the θ created here Forced synchronous rotation is performed. The initial phase is the initial integration value.

  The speed estimator 4 is generally known and includes a rotor phase error estimator (not shown) and a PLL (Phase Locked Loop) controller.

Based on the above configuration, the phase estimation and application algorithm at the time of rotor stop / restart will be described.
If the positioning current vector V1 can be arranged in the vicinity of the d-axis in the rotating coordinate system, the back-return / advance rotation of the rotor R at the time of startup hardly occurs. That is, as shown in FIG. 5A, if the positioning current vector V1 is appropriately set in a phase separated from the d-axis, the torque is generated by the q-axis current component Iq as shown in FIG. Occurs, and the dq axes of the rotor R start to rotate. The rotation convergence position has a phase very close to the d-axis as shown in FIG.

  Therefore, as shown in FIG. 5C from the beginning, if the positioning current vector V1 can be arranged in the vicinity of the q axis, torque in the rotational direction can be prevented from being generated, so that the rotor R does not rotate during positioning. Can enter into synchronous rotation.

Therefore, in the present embodiment, the stop phase estimation unit 7 shown in FIG. 4 is allowed to estimate the d-axis phase angle θ ₀ that is the stop phase of the rotor R. The stop phase estimation unit 7 includes a detection unit 71 immediately before stop, a UVW comparison unit 72, and a phase determination unit 73. The just before stop detecting unit 71 monitors the phase current and detects whether or not the phase current has reached a predetermined current value as a phase current value immediately before the rotor R stops. The UVW comparison unit 72 applies a phase current vector (hereinafter referred to as “short circuit”) to the plurality of sectors 1 to 6 on the stationary coordinates (α, β) classified by the magnitude relation of the phase current. The brake current vector V2 ")) is compared with the magnitude relation of Iu, Iv, and Iw to determine which sector belongs to immediately before the stop, that is, when the immediately before stop detecting unit 71 detects a predetermined current value. The phase determination unit 73 determines a stop phase based on the comparison result of the UVW comparison unit 72.

  Thus, by determining which sector the short-circuit brake current vector V2 belongs to based on the magnitude relationship of the phase currents, the direction of the short-circuit brake current vector V2 can be easily grasped.

Hereinafter, an algorithm for estimating the d-axis phase angle immediately before the rotor R is stopped will be described. Here, the description will be made assuming that the electrical angular velocity is ω _2n .

である。 The voltage equation of a permanent magnet synchronous motor is a general PM motor model.

It is.

The short-circuit brake is a motor winding short-circuit state, that is, a state where the motor applied voltage is 0.

At the time of short-circuit braking, the dq current is considered not to change suddenly, so the differential term (p term) is also 0,

From this, the following Iq and Id are obtained.

That is, it can be seen that Id and Iq change depending on the rotational speed ω _2n during short-circuit braking.

FIG. 6 shows a current vector locus when the rotational speed is changed from ± 900 [rpm] to 0 [rpm] by the short-circuit brake from the above formula. However, R = 2.2 [Ω], Ld = 25 [mH], Lq = 28 [mH], Φ = 0.174 [Wb], and P _pn = 8.

  When the rotor R is rotating forward, that is, counterclockwise, the short-circuit brake current vector V2 at a high speed of 900 [rpm] is close to the d-axis in the third quadrant. On the other hand, the short-circuit brake current vector V2 rotates counterclockwise while decreasing the norm as the rotational speed decreases, and reaches the origin when the motor M is stopped. Therefore, the short-circuit brake current vector V2 immediately before the motor M is stopped is considered to be located in the vicinity of the q-axis negative side.

  When the rotor R rotates in the reverse direction, that is, in the clockwise direction, the short-circuit brake current vector V2 when the rotational speed is a high speed of 900 [rpm] is a vertically symmetrical vector from the position near the d-axis in the third quadrant. Draw a trajectory and approach the origin clockwise. The short-circuit brake current vector V2 immediately before the motor M is stopped is considered to be located in the vicinity of the q-axis positive side.

  Since the motor torque is proportional to Iq, torque in the direction opposite to the rotation direction, that is, braking torque is generated.

FIG. 7 shows α-β stationary coordinates and dq rotation coordinates, and shows a short-circuit braking current vector V2 immediately before stopping. The short-circuit brake current vector V2 during forward rotation exists in the third quadrant of the dq coordinate system. As ω _2n decreases, the short-circuit brake current vector V2 becomes shorter in vector length and gradually approaches the negative q-axis side. When the position immediately before the stop is in FIG. 7A, the short-circuit brake current vector V2 belongs to the fourth quadrant, sector 5.

Further, in the negative rotation, the dq coordinate table rotates at −ω _2n , and the short circuit brake current vector V2 exists in the second quadrant of the dq coordinate. As ω _2n decreases, the short-circuit brake current vector V2 decreases in vector length and gradually approaches the q-axis positive side. In the case of FIG. 7B, the short-circuit brake current vector V2 belongs to the second quadrant, sector 3.

It can be determined from Table 1 by examining the magnitude relationship among the currents Iu, Iv, and Iw of each phase according to Table 1. The UVW comparator 72 extracts the amplitude values of Iu, Iv, and Iw, compares the large, medium, and small relationships, and determines in which sector the short-circuit brake current vector V2 exists.

As shown in FIG. 8, the position rotated clockwise by 90 ° to 100 ° is the d-axis position. The phase determination unit 73 first holds the data in Table 1, to determine the sector center phase angle theta _M from the sector in which indexing is UVW comparing unit 72, a phase angle theta ^∧ of the short-circuit brake current vector V2.

Thus, by the center phase angle theta ^∧ judgment sectors between the phase angle theta ^∧ of the short-circuit brake current vector V2, it is possible to estimate the phase angle of the d-axis without any special operation.

  However, if the rotor R is completely stopped, the phase current of the short-circuit brake becomes 0, so that the determination becomes impossible. Therefore, the detection unit 71 just before stopping according to the present embodiment detects that the phase current immediately before the rotor R stops is below a predetermined value (for example, 0.9 [A]), and at that time, UVW The comparison unit 72 and the phase determination unit 73 are operated.

The immediately before stop detecting unit 71 first acquires the amplitude of the current vector from the following equation.

Further, the phase angle from the q axis to the current vector can be obtained from the following equation.

  FIG. 9 shows the magnitude and phase of the short-circuit brake current vector V2.

  When the phase current amplitude ia = 0.9 [A], the phase difference between the d-axis and the current vector is about 99 °. Incidentally, at this time, the rotation speed is about 13 [rpm], which can be regarded as just before the stop.

That is, in detecting the position of the d-axis during short-circuit braking,
(1) The UVW comparison unit 72 obtains a sector in which the short-circuit brake current vector V2 exists from the magnitude relationship of Iu, Iv, and Iw when the short-circuit brake phase current amplitude reaches a threshold value (for example, 0.9 [A]). .
(2) The phase determination unit 73 sets the obtained center phase angle θ _M of the sector as the phase angle θ ^の of the short-circuit current vector V2 at the time of stop, and then, as shown in FIG. For example, advance the phase by 100 °. The angle at that position is the d-axis phase angle θ ₀ indicating the rotor stop phase with respect to the α-axis.
θ ₀ = θ _M ± θx
The predetermined angle θx corresponds to a value obtained by adding the error angle and 90 ° that is the dq axis angle. The error angle includes a phase difference between the short-circuit brake current vector V2 immediately before the stop and the q axis.

  FIG. 10 is a flowchart showing an outline of a procedure performed by the control means C using the short-circuit brake control unit 61, the stop phase estimation unit 7, and the storage unit 8. When the program starts,

<Step S1>
It is determined whether or not rotation has started. If it is YES, it will move to Step S2, and if it is NO, it will return before Step S1.

<Step S2>
It is determined whether or not the rotation ON period has ended. Here, it is the ON period during forward rotation during washing and rinsing. If yes, return to step S3; if no, return to step S2.

<Step S3>
The short-circuit brake is activated upon completion of the rotation period. The short-circuit braking is performed by connecting the switches SW4 and SW5 to 0V in FIG.

<Step S4>
Calculate the amplitude of the short-circuit brake current. As described above, the magnitude of the short-circuit brake current can be monitored using Id and Iq, but here, the amplitude is monitored using the phase current amplitude Im. Im is according to the following equation.

<Step S5>
It is determined whether Im <ref. ref is a current value at which the rotation is determined to have substantially stopped. If it is YES, it will move to step S6, and if it is NO, it will return before step S3.

<Step S6>
Sectors are determined based on the relationship between Iu, Iv, and Iw. The phase currents Iu, Iv, Iw are detected from the motor M.

<Step S7>
The stop phase angle θ ₀ of the d axis is calculated from the center phase θ _M of the sector in Table 1, and is stored as an integral initial value in the storage unit 8 of FIGS. 3 and 4, and the process returns to the start.

  Thereby, the positioning current vector V1 is given an initial value in the direction of FIG. 5C close to the d-axis, and the synchronous rotation can be smoothly started from this state.

Second Embodiment
Next, a second embodiment of the present invention will be described with reference to FIG.

The algorithm of the embodiment, the measurement of the center phase theta _M of the short-circuit brake current vector V2 is sector unit. For this reason, a phase error of up to ± 30 ° occurs.

  In practice, such an error does not cause any particular problem in realizing smooth start-up, but smoother start-up can be realized by incorporating an algorithm that increases the d-axis estimation accuracy.

The stop phase estimation unit 7 of the present embodiment uses the estimated center phase angle θ _M of the sector as a reference phase angle, and a correction angle Δθ derived from the reference phase angle θ _M based on a predetermined relationship based on the phase current. the angle that takes into account the phase angle theta ^∧ positioning current vector V1 and configured to estimate a phase angle theta ₀ of the d-axis by adjusting the predetermined angle θx in the phase angle theta ^∧.

By doing so, it is possible to estimate the d-axis phase angle θ ₀ with higher accuracy by a relatively simple calculation.

  Specifically, since there is an algorithm shown in Table 2 that approximates the phase at that time from the instantaneous value of the three phases of the triangular sine wave, it is used.

If the correction angle θ based on U, V, and W as shown in Table 2 is used for each sector determined in the above embodiment, the calculation result can be made closer to a true value.

  Steps S6a to S6d in FIG. 11 represent the phase determination and storage unit procedures applied in place of steps S6 and S7 in the above embodiment.

<Step S6a>
theta ^∧, it calculates the correction angle theta ^∧ from Δθ by the following equation.

<Step S6b>
It is determined whether the rotation direction is negative.

<Steps S6c and S6d>
Step S6c, in 6b, by ± according radians corresponding to a predetermined angle [theta] x = 100 ° in the rotational direction, determine the stopping phase angle theta ₀ of the d-axis.

<Step S7a>
The integration initial value θ ₀ is stored in the storage unit 8 and the process returns to the start.

For example, when the rotor R stops at t = 0.8 [s], the phase current in Table 3 below is read at t = 0.78 [s].

  Since Iw> Iv> Iu, the short-circuit brake current vector V2 is located in the sector 4 at this time.

Therefore,

According to the calculation of the first embodiment, the angle is 210 °, so that the phase θ ^の of the short-circuit current vector V2 closer to the q-axis phase is obtained. Then, 332.6 °, which is a predetermined angle of 100 ° from 232.6 °, is determined as the d-axis phase angle θ ₀ . For this reason, the positioning current vector V1 is given in a direction substantially matching the d-axis, and from this state, it is possible to start the synchronous rotation at the start more smoothly.

<Modification>
Regarding the short-circuit brake, the short-circuit brake is realized by setting the dq axis voltage to 0 [V] in the above description, but the short circuit brake control unit 161 of FIG. 12 is configured regardless of the dq axis voltage. In the switching drive circuit, the three-phase U, V, depending on whether (1) all the high-side switching elements SW (H) are turned off or (2) all the low-side switching elements SW (L) are turned off. , W may be short-circuited.

  According to this, since PWM switching is not performed, there is an advantage that there is no influence of dead time, no switching noise is generated, and the computational load of the computer is light.

  Although the embodiments of the present invention have been described above, the rotor phase estimation, the storage mechanism, and the like are not limited to the above-described embodiments.

  Other configurations can be variously modified without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Washing machine 7 ... Stop phase estimation part 8 ... Memory | storage part 15 ... Pulsator 61 ... Short-circuit brake control part C ... Control means M ... Motor R ... Rotor V1 ... Positioning current vector V2 ... Short-circuit brake current vector (theta) ₀ ... Rotor stop phase θ _M ... Center phase angle (reference phase angle)
θx ... predetermined angle Δθ ... correction angle

Claims (4)

A pulsator for stirring laundry, a permanent magnet synchronous motor for driving the pulsator forward and reverse, and a control means for controlling the start and stop of the motor with respect to the rotor without a sensor;
The control means, a short-circuit brake control unit that performs a short-circuit brake at the time of stop, and a stop phase estimation unit that estimates a phase at which the rotor has stopped from a phase current immediately before stop among phase currents flowing through the winding by the short-circuit brake, And a storage unit that stores a stop phase, extracts a rotor stop phase estimated from the storage unit at the time of start-up, and generates a positioning current vector that is a current vector for positioning the rotor at the start of synchronous rotation based on this A washing machine characterized by that.   The stop phase estimator has a short-circuit brake current vector, which is a vector of phase current flowing in the winding by the short-circuit brake, for any of the sectors on the static coordinates classified by the magnitude relation of the phase current. The washing machine according to claim 1, wherein it is determined whether or not it belongs to a sector.   The stop phase estimator uses the determined central phase angle of the sector as the phase angle of the short-circuit brake current vector existing in the vicinity of the q-axis of the rotating coordinate system, and estimates the d-axis phase angle by adding or subtracting a predetermined angle to this phase angle. The washing machine according to claim 2. The stop phase estimation unit sets the angle obtained by adding a correction angle derived from a predetermined correspondence relationship based on the phase current to the estimated reference phase angle of the sector as the phase angle of the short-circuit brake current vector existing near the q axis, The washing machine according to claim 2, wherein a predetermined angle is added to or subtracted from the phase angle to estimate the d-axis phase angle.

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