JP5670077B2 - Motor control device and washing machine - Google Patents

Description

  The present invention includes a motor control device that calculates a rotational speed of a motor at a change timing of sensor signals output from a plurality of rotational position sensors that detect a rotor position of the motor and performs speed control, and the motor control device. Relates to a washing machine.

For example, in a system that controls a motor with a large load torque fluctuation and a small inertia of the drive system, such as a washing machine, the speed fluctuation is large. Stopping rotation may occur. As an example of such a rotation stop, although the motor drive system can output a torque that is normally sufficient to continue the rotation, the control system responds to a large fluctuation in the load torque, resulting in an output. It may be caused by lowering the torque more than necessary.
FIG. 12 shows a state in which the laundry inside is swept up by the baffle when the drum of the drum type washing machine starts rotating, for example. (A) From the state where the drum has stopped rotating and the laundry is at the lowest position in the drum, (b) the drum starts to rotate, and its rotational position is close to 90 degrees. When it is in the state of being lifted up, the load on the motor becomes extremely large.

  Various techniques have been proposed in the past for preventing the rotation of a motor from being stopped or detecting a rotation abnormality. For example, in Patent Document 1, when three rotational position sensors are used for a brushless motor, each sensor signal is absorbed in order to absorb fluctuations in the edge interval (time width) of each sensor signal caused by variations in these attachment positions. A technique is disclosed in which the rotational speed of a motor is determined from a time corresponding to a half cycle or one cycle of a signal and variation is eliminated. Japanese Patent Application Laid-Open No. 2004-228561 discloses a technique for detecting abnormal rotation of a motor by monitoring a pulse width of a pulse signal output from a hall element arranged in a fan motor of a copier.

Patent Document 1 does not disclose details of rotation control. However, in general, in the configuration in which the rotation speed is detected based on the pulse signal output as the motor rotates, the edge input of the pulse signal is performed. The speed is determined at the moment when there is (see, for example, FIG. 6 of Patent Document 1). Accordingly, the energization current or applied voltage to the motor is adjusted at the timing when the edge is input, and the output torque of the motor is controlled to make the rotation speed coincide with the target value.
However, for example, if the load suddenly increases from a state where the actual current detected immediately before the torque fluctuation occurs is larger than the target value and the energization current is reduced, there is no time to increase the energization current, and the rotation The speed may drop rapidly and the sensor pulse output may be lost. In such a case, since a decrease in the rotation speed is not detected until the next sensor pulse is generated, the motor current does not increase in the speed control, and the rotation stops and an abnormality is detected. Therefore, it is impossible to cope with the rotation stop when the load torque fluctuation is large.

Further, Patent Document 2 is a technique for detecting a rotation abnormality, and since the motor is restarted after detecting a state where the rotation has stopped once, it does not contribute to a quick response.
Further, paragraph [0098] of Patent Document 3 discloses that the microcomputer counts the number of interruptions generated according to the output of the three-phase sensor pulse edge per unit time, thereby measuring the number of rotations of the rotor. Yes.

JP 2003-264990 A JP 2000-166272 A JP-A-9-74790

  In the method of Patent Document 3, since the number of rotations of the motor is measured every unit time, the problem as in Patent Document 1 does not occur. However, in this case, unless the unit time is sufficiently long with respect to the output interval of the three-phase pulse edge, the resolution of the rotational speed becomes coarse. The number of sensors such as Hall elements that are generally used for brushless DC motors is at most three, and if the period of rotation control becomes too long, precise control cannot be performed. That being said, using a high output pulse number such as a rotary encoder will lead to an increase in cost and increase the size of the product.

  The present invention has been made in view of the above circumstances, and a purpose of the present invention is to provide a motor control device that can be restarted within a short time as much as possible even when rotation caused by large load torque fluctuations has stopped. And a washing machine including the motor control device.

In order to achieve the above object, a motor control device according to claim 1 includes a plurality of rotational position sensors for detecting a rotor position of the motor;
During the rotation of the motor, the rotation speed of the motor is calculated at a timing when sensor signals output from the plurality of rotation position sensors change, and a current flowing through the winding of the motor is calculated based on the calculated rotation speed. Speed control means is provided for controlling the speed, and when the state in which the sensor signal does not change continues for a predetermined monitoring time or longer, the speed control means for increasing the amount of current to be supplied to the winding of the motor from the current control value. It is characterized by.
With this configuration, the motor speed control is unstable even when the inertia of the drive system is small and the number of changes in sensor signals output from a plurality of rotational position sensors is small for one electrical angle cycle. Thus, it is possible to increase the rotation speed of the motor by detecting at an early stage.

  A washing machine according to an eighth aspect includes a motor that generates a rotational driving force for performing washing and dehydration, and the motor control device according to any one of the first to seventh aspects. That is, since the washing machine generally has a small inertia of the drive system and a large fluctuation of the load torque, the present invention can be effectively applied.

According to the motor control device of the first aspect, it is possible to detect at an early stage that the speed control of the motor has become unstable, increase the rotational speed of the motor, and return the speed control to a stable state. it can.
According to the washing machine of claim 8, even when the load torque fluctuates greatly according to the amount and distribution state of the laundry in the rotating tub, the operation time is shortened by reducing the period during which the motor stops rotating as much as possible. can do.

The flowchart which is 1st Example and shows the control content by a control circuit. Flow chart showing processing contents of "speed control" (A) is each sensor signal of a hall sensor, (b) is q-axis current command value Iqref, (c) is a figure which shows the example of a change of q-axis current Iq. (A) is a figure which shows the change pattern of a three-phase sensor signal, (b) is a figure which shows the detection speed and motor current change of a motor. (A) is a top view which shows the structure of the rotor of a drum motor, (b) is a figure which shows the state from which the magnetic flux of the magnet which a Hall sensor detects changes. Diagram showing drum motor drive control system Functional block diagram showing the control system of sensorless vector control Longitudinal side view showing the configuration of a drum-type washing and drying machine FIG. 1 equivalent view showing the second embodiment 3 equivalent view (part 1) Figure 3 equivalent (part 2) The figure which shows the state in a drum when a motor starts about a prior art

(First embodiment)
Hereinafter, a first embodiment will be described with reference to FIGS. FIG. 8 is a longitudinal side view showing the configuration of the drum type washing and drying machine. The outer box 1 has a front plate, a rear plate, a left side plate, a right side plate, a bottom plate, and a top plate and has a hollow shape. A front plate of the outer box 1 is formed with a through-hole-like entrance 2. . A door 3 is attached to the front plate of the outer box 1. The door 3 can be operated by the user between the closed state and the open state from the front. The door 2 is closed when the door 3 is closed, and the door 2 is opened when the door 3 is open. A water receiving tank 4 is fixed inside the outer box 1. The water receiving tank 4 has a cylindrical shape with a closed rear surface, and is arranged in an inclined state in which the axial center line CL descends from the front toward the rear. The front surface of the water receiving tank 4 is open. When the door 3 is closed, the door 3 closes the front surface of the water receiving tank 4 in an airtight state.

  A drum motor 5 is fixed to the rear plate of the water receiving tank 4 so as to be located outside the water receiving tank 4. The drum motor 5 is a brushless DC motor, and the rotating shaft 6 of the drum motor 5 protrudes into the water receiving tank 4. The rotating shaft 6 is disposed so as to overlap the axial center line CL of the water receiving tank 4, and a drum (rotating tank) 7 is fixed to the rotating shaft 6 inside the water receiving tank 4. The drum 7 has a cylindrical shape with a closed rear surface, and rotates integrally with the rotary shaft 6 in accordance with the operation state of the drum motor 5. The front surface of the drum 7 faces the entrance / exit 2 from the rear via the front surface of the water receiving tank 4, and the interior of the drum 7 includes the entrance / exit 2 and the front surface of the water receiving tank 4 from the front with the door 3 opened. The laundry is put in and out through the front surface of the drum 7.

  A plurality of through holes 8 are formed in the drum 7, and the internal space of the drum 7 is connected to the internal space of the water receiving tank 4 through each of the plurality of through holes 8. A plurality of baffles 9 are fixed to the inner peripheral surface of the drum 7. Each of the plurality of baffles 9 is moved in the circumferential direction around the axis line CL by the rotation of the drum 7, and the laundry in the drum 7 is circular while being caught on each of the plurality of baffles 9. After moving in the circumferential direction, it is stirred by dropping by gravity.

  A water supply valve 10 is fixed inside the outer box 1. The water supply valve 10 has an inlet and an outlet, and the inlet of the water supply valve 10 is connected to a tap. The water supply valve 10 uses a water supply valve motor (not shown) as a drive source, and the outlet of the water supply valve 10 is switched between an open state and a closed state according to the amount of rotation of the water supply valve motor. The outlet of the water supply valve 10 is connected to the water injection case 11, and when the water supply valve 10 is opened, tap water is injected into the water injection case 11 through the water supply valve 10. The water injection case 11 is fixed inside the outer box 1 at a higher position than the water receiving tank 4 and has a cylindrical water inlet 12. The water injection port 12 is inserted into the water receiving tank 4, and the tap water injected from the water supply valve 10 into the water injection case 11 is injected into the water receiving tank 4 from the water injection port 12.

  An upper end portion of a drain pipe 13 is connected to the water receiving tank 4 at the bottom, and a drain valve 14 is interposed in the drain pipe 13. This drain valve 14 uses a drain valve motor (not shown) as a drive source, and can be switched between an open state and a closed state according to the rotation amount of the drain valve motor. In the closed state of the drain valve 14, tap water injected into the water receiving tank 4 from the water inlet 12 is stored in the water receiving tank 4, and in the open state of the drain valve 14, tap water in the water receiving tank 4 passes through the drain pipe 13. It is discharged outside the water receiving tank 4.

  A main duct 15 is fixed to the bottom plate of the outer box 1 below the water receiving tank 4. The main duct 15 has a cylindrical shape directed in the front-rear direction, and the lower end portion of the front duct 16 is connected to the front end portion of the main duct 15. The front duct 16 has a cylindrical shape directed in the vertical direction, and the upper end of the front duct 16 is connected to the internal space of the water receiving tank 4 at the front end of the water receiving tank 4. A fan casing 17 is fixed to the rear end portion of the main duct 15. The fan casing 17 has a through-hole-like intake port 18 and a cylindrical exhaust port 19, and the internal space of the fan casing 17 is connected to the internal space of the main duct 15 via the intake port 18.

  A fan motor 20 is fixed to the fan casing 17 outside the fan casing 17. The fan motor 20 has a rotating shaft 21 protruding inside the fan casing 17, and a fan 22 is fixed to the rotating shaft 21 so as to be positioned inside the fan casing 17. The fan 22 is a centrifugal type that sucks air from the axial direction and discharges it in the radial direction. The air inlet 18 of the fan casing 17 faces the fan 22 from the axial direction, and the air outlet 19 of the fan casing 17 is It faces the fan 22 from its radial direction.

  The lower end of the rear duct 23 is connected to the exhaust port 19 of the fan casing 17. The rear duct 23 has a cylindrical shape directed in the vertical direction, and the upper end of the rear duct 23 is connected to the internal space of the water receiving tank 4 at the rear end of the water receiving tank 4. The rear duct 23, the fan casing 17, the main duct 15, the front duct 16, and the water receiving tank 4 constitute an annular circulation duct 24 having the internal space of the water receiving tank 4 as a start point and an end point, respectively, and the door 3 is closed. When the fan motor 20 is operated in a state, the fan 22 rotates in a certain direction, so that the air in the water receiving tank 4 is sucked from the front duct 16 into the main casing 15 and into the fan casing 17. The water is returned from the casing 17 to the water receiving tank 4 through the rear duct 23.

A compressor (compressor) 25 is fixed inside the outer box 1. The compressor 25 is disposed outside the circulation duct 24 and has a discharge port for discharging the refrigerant and a suction port for sucking the refrigerant. The compressor 25 uses a built-in compressor motor (not shown) as a drive source, and the compressor motor is also composed of a brushless DC motor.
A condenser (condenser) 26 is fixed inside the main duct 15. The condenser 26 heats air and is configured by fixing each of a plurality of plate-like heating fins 31 in contact with each other on the outer peripheral surface of one refrigerant pipe 27 that bends in a meandering manner. The refrigerant pipe 27 of the condenser 26 is connected to the outlet of the compressor 25, and the refrigerant discharged from the outlet of the compressor 25 enters the refrigerant pipe 27 of the condenser 26 when the compressor motor is operating.

  A capillary tube (decompressor) (not shown) is fixed inside the outer box 1. The capillary tube is connected to the refrigerant pipe 27 of the condenser 26 and is arranged outside the circulation duct 24. The capillary tube restricts the flow of the refrigerant on the downstream side of the condenser 26, and is composed of a single pipe. An electronic expansion valve [PMV: Pulse Motor Valve] may be used instead of the capillary tube. An evaporator 28 is fixed inside the main duct 15. The evaporator 28 cools the air and is disposed upstream of the condenser 26 in the air flow. In addition, the heat pump 29 is comprised by piping etc. which connect these, such as the compressor 25, the capacitor | condenser 26, the evaporator 28, the refrigerant | coolant pipe | tube 27, and a capillary tube.

FIG. 6 schematically shows a drive control system of the drum motor 5. The inverter circuit (PWM control system inverter) 31 is configured by connecting six IGBTs (semiconductor switching elements) 32a to 32f in a three-phase bridge, and a flywheel diode is provided between the collector and emitter of each of the IGBTs 32a to 32f. 33a to 33f are connected.
The emitters of the lower arm side IGBTs 32d, 32e, and 32f are connected to the ground via shunt resistors (current detection elements) 34u, 34v, and 34w. The common connection point between the emitters of the IGBTs 32d, 32e, and 32f and the shunt resistors 34u, 34v, and 34w is connected to each input of the amplifier circuit unit 36 via the level shift circuit 35 that includes a voltage dividing resistor (voltage dividing ratio 1: 1). Connected to the terminal. Incidentally, since a maximum of 15 A flows through the windings 5u to 5w of the drum motor 5, the resistance values of the shunt resistors 34u to 34w are set to 0.033Ω, for example. Further, the resistance value of the voltage dividing resistor constituting the level shift circuit 35 is set to 1 kΩ, for example.

  A driving power supply circuit 37 is connected to the input side of the inverter circuit 31. The drive power supply circuit 37 rectifies a 100-V commercial AC power supply 38 by a full-wave rectifier circuit 39 composed of a diode bridge and a double-voltage full-wave rectifier by two capacitors 40 a and 40 b connected in series, and a direct current of about 280 V A voltage is supplied to the inverter circuit 31. Each phase output terminal of the inverter circuit 31 is connected to each phase winding 5u, 5v, 5w of the drum motor 5.

The control circuit (speed control means) 30 A / D converts the current of each phase flowing through the windings 5 u to 5 w of the motor 5 obtained through the amplifier circuit unit 36 by an A / D conversion circuit (ADC) 30 a. Then, the phase θ of the secondary rotating magnetic field and the rotational angular velocity ω are estimated based on the current value, the output voltage of the inverter, and the motor constant (winding resistance value and inductance), and the three-phase An excitation current component Id and a torque current component Iq are obtained by performing orthogonal coordinate transformation and dq (direct-quadrature) coordinate transformation of the current.
When a speed command is given from the outside, the control circuit 30 generates current commands Idref and Iqref based on the estimated phase θ, rotational angular velocity ω, and current components Id and Iq, and converts them into voltage commands Vd and Vq. Then, rectangular coordinate transformation and three-phase coordinate transformation are performed. Finally, a drive signal is generated as a PWM signal, and is output to the windings 5 u to 5 w of the motor 5 via the inverter circuit 31.

  The first power supply circuit 41 steps down the drive power supply of about 280V supplied to the inverter circuit 31 to generate a control power supply of 16V and supplies it to the drive circuit 42 and the high voltage drive circuit 43. The second power supply circuit 44 also steps down the driving power supply to generate a 3.3V power supply and supplies it to the control circuit 30 and the amplifier circuit unit 36. The high voltage driver circuit 43 is arranged to drive the IGBTs 32 a to 32 c on the upper arm side in the inverter circuit 31.

  The rotor of the drum motor 5 is provided with a hall sensor 45 (u, v, w) constituted by, for example, a hall IC for use at the time of startup, and the hall sensor 45 (rotation position sensor, position detection means). The position signals of the rotor output from the control signal Hu; Hv, Hw are given to the control circuit 30. That is, when the drum motor 5 is started, vector control is performed using the hall sensor 45 up to a rotational speed (for example, about 30 rpm) at which the rotor position can be estimated. Switch to sensorless vector control without using the sensor 45. The compressor motor has a configuration that is substantially symmetric to the drive system of the drum motor 5, although not specifically illustrated.

  Further, a series circuit of resistance elements 46 a and 46 b is connected between the output terminal of the power supply circuit 37 and the ground, and a common connection point thereof is connected to an input terminal of the control circuit 30. The control circuit 30 reads the input voltage of the inverter circuit 31 divided by the resistance elements 46a and 46b and uses it as a reference for determining the PWM signal duty. In addition, the control circuit 30 controls various electrical components 47 such as a door lock control circuit and a drying fan motor, and inputs / outputs operation signals, control signals, and the like with the display / operation board 48 described above. To do. Furthermore, in order to improve the S / N ratio, the control circuit 30 increases the amplification factor of the amplification circuit unit 36 when performing normal motor control, and a magnet disposed in the rotor of the drum motor 5 as described later. When the magnetization control is performed, switching is performed so as to reduce the amplification factor. Further, when the overcurrent determination function built in the amplifier circuit section 36 outputs an overcurrent detection signal, a protection operation is performed accordingly.

FIG. 5 is a plan view showing the configuration of the rotor of the outer rotor type drum motor 5 (permanent magnet motor). The drum motor 5 includes a stator 51 and a rotor 52 arranged on the outer periphery thereof. The stator 51 includes a stator core 53 and stator windings 5 (u, v, w). The stator core 53 is formed by laminating a plurality of punched and formed soft magnetic bodies of silicon steel plates and caulked, and includes an annular yoke portion 53a and a large number of teeth portions projecting radially from the outer periphery of the yoke portion 53a. 53b. The surface of the stator core 53 is covered with PET resin (mold resin) except for the front end surface of each tooth portion 53b.
A plurality of mounting portions 54 made of this PET resin are integrally formed on the inner peripheral portion of the stator 51. The mounting portions 54 are provided with a plurality of screw holes 54a. By fixing these mounting portions 54, the stator 51 is fixed to the back surface of the water receiving tub 4 of the drum type washing and drying machine in this case. . The stator winding 5 (u, v, w) has three phases and is wound around each tooth portion 53b.

  The rotor 52 has a configuration in which the frame 55, the rotor core 8, and the plurality of permanent magnets 9 are integrated with a mold resin (not shown). The frame 55 is formed into a flat bottomed cylindrical shape by pressing, for example, an iron plate that is a magnetic material. The rotor core 56 is formed by laminating and laminating a large number of silicon steel plates, which are soft magnetic bodies punched and formed in a substantially annular shape, and is disposed on the inner peripheral portion of the frame 55. The inner peripheral surface of the rotor core 56 (the surface that faces the outer peripheral surface of the stator 2 (the outer peripheral surface of the stator core 53) and forms a gap between the stator 2) has a plurality of arcs protruding inward. It is formed in an uneven shape having a convex portion (magnetic pole tip) 56a.

  A rectangular insertion hole that penetrates the rotor core 56 in the axial direction (lamination direction of the silicon steel plates) is formed inside the plurality of protrusions 56a, and the plurality of insertion holes are annularly arranged in the rotor core 56. It becomes the composition. The permanent magnet 57 includes a rectangular neodymium magnet 57a (high coercivity permanent magnet) inserted into the insertion hole, and a rectangular samarium-cobalt magnet (hereinafter referred to as a samacoba magnet) 57b (low coercivity permanent magnet). It is composed of In this case, the coercive force of the neodymium magnet 57a is about 700 k to 900 kA / m, and the coercive force of the sumakoba magnet 57b is about 100 k to 200 kA / m. The total number of permanent magnets 57 is 48, of which 6 are sumakoba magnets 57b and 42 are neodymium magnets 57a.

  In FIG. 6, AF is attached | subjected to the position where the Samakoba magnet 57b is arrange | positioned. Five neodymium magnets 57a arranged between A and B, nine neodymium magnets 57a arranged between B and C, five neodymium magnets 57a arranged between C and D, D- There are nine neodymium magnets 57a disposed between E, five neodymium magnets 57a disposed between E-F, and nine neodymium magnets 57a disposed between F-A. In this arrangement, the average value of the induced voltages generated for the same phase is set to the same value to suppress the generation of cogging torque. The drum motor 5 has a configuration of 48 poles / 36 slots, and 4 poles correspond to 3 slots (4 poles / 3 slots).

  The neodymium magnet 57a has a high coercive force, and the samacoba magnet 57b has a low coercive force. The magnetization amount of the samacoba magnet 57b is increased when a magnetizing current is applied through the stator 51 as will be described later. On the basis that the amount of magnetization of the neodymium magnet 57a does not change with a current that can be changed, the former is referred to as high coercivity and the latter is referred to as low coercivity.

  FIG. 7 is a diagram showing functional blocks of sensorless vector control performed by the control circuit 30 for the drum motor 5 (and the compressor motor). This configuration is the same as that disclosed in, for example, Japanese Patent Application Laid-Open No. 2003-181187, and will be schematically described here. In FIG. 7, (α, β) represents an orthogonal coordinate system obtained by orthogonal transformation of a three-phase (UVW) coordinate system with an electrical angle interval of 120 degrees corresponding to each phase of the drum motor 5, and (d, q) is The coordinate system of the secondary magnetic flux which is rotating with rotation of the rotor of the drum motor 5 is shown.

  The subtractor 62 is supplied with the target speed command ωref from the speed command output unit 61 as a subtracted value and the detected speed ω of the drum motor 5 detected by the estimator 63 as a subtracted value. The subtraction result is given to a speed PI (Proportional-Integral) control unit 65. The speed PI control unit 65 performs PI (proportional integration) control based on the difference between the target speed command ωref and the detected speed ω, and generates and subtracts the q-axis current command value Iqref and the d-axis current command value Idref. Are output as subtracted values to the devices 66q and 66d, respectively. The subtractors 66q and 66d are respectively provided with the q-axis current value Iq and the d-axis current value Id output from the αβ / dq conversion unit 67 as subtraction values, and the subtraction results are respectively supplied to the current PI control units 68q and 68d. Given. The control period in the speed PI control unit 65 is set to 1 msec.

  The current PI controllers 68q and 68d perform PI control based on the difference amount between the q-axis current command value Iqref and the d-axis current command value Idref, and generate the q-axis voltage command value Vq and the d-axis voltage command value Vd. And output to the dq / αβ conversion unit 69. The dq / αβ conversion unit 69 is given a rotational phase angle (rotor position angle) θ of the secondary magnetic flux detected by the estimator 63, and voltage command values Vd and Vq are converted into voltage commands based on the rotational phase angle θ. Convert to values Vα and Vβ.

The voltage command values Vα and Vβ output from the dq / αβ conversion unit 69 are converted into three-phase voltage command values Vu, Vv and Vw by the αβ / UVW conversion unit 70 and output. The voltage command values Vu, Vv, Vw are given to one fixed contact 71ua, 71va, 71wa of the changeover switches 71u, 71v, 71w, and are output from the initial pattern output unit 76 to the other fixed contact 71ub, 71vb, 71wb. Voltage command values Vus, Vvs, and Vws are given. The movable contacts 71uc, 71vc, 71wc of the changeover switches 71u, 71v, 71w are connected to the input terminal of the PWM forming unit 73.
The PWM forming unit 73 modulates a 15.6 kHz carrier (triangular wave) based on the voltage command values Vus, Vvs, Vws or Vu, Vv, Vw, and outputs PWM signals Vup (+,-), Vvp (+, -), Vwp (+,-) is output to the inverter circuit 31. The PWM signals Vup to Vwp are output as signals having a pulse width corresponding to the voltage amplitude based on the sine wave so that, for example, a sine wave current is passed through the phase windings 5u, 5v, 5w of the drum motor 5. .

The A / D conversion circuit 30a outputs current data Iau, Iav, Iaw obtained by A / D converting voltage signals appearing at the emitters of the IGBTs 33d to 33f to the UVW / αβ conversion unit 75. The UVW / αβ conversion unit 75 converts the three-phase current data Iau, Iav, Iaw into two-axis current data Iα, Iβ in an orthogonal coordinate system according to a predetermined arithmetic expression. Then, the biaxial current data Iα and Iβ are output to the αβ / dq converter 67.
The αβ / dq converter 67 obtains the rotor position angle θ of the drum motor 5 from the estimator 63 at the time of vector control, so that the biaxial current data Iα and Iβ are represented on the rotational coordinate system (d, q) according to a predetermined arithmetic expression. Are converted to the d-axis current value Id and the q-axis current value Iq, and are output to the estimator 63 and the subtractors 66d and 66q as described above.

  The estimator 63 estimates the rotor position angle θ and the rotational speed ω based on the q-axis voltage command value Vq, the d-axis voltage command value Vd, the q-axis current value Iq, and the d-axis current value Id, and outputs them to each unit. . Here, when the drum motor 5 is activated, the activation pattern by the initial pattern output unit 76 is applied and forced commutation is performed. Thereafter, when the hall sensor 45 performs vector control based on the sensor signal, the estimator 63 is activated to shift to sensorless vector control in which the position angle θ and the rotational speed ω of the rotor of the drum motor 5 are estimated. In the case of a compressor motor, the process shifts from forced commutation to sensorless vector control.

  The switching control unit 77 controls switching of the selector switch 71 based on the duty information of the PMW signal given from the PWM forming unit 73. Note that in the above configuration, the configuration excluding the inverter circuit 31 is a block of functions realized by the software of the control circuit 30. The current control period in the vector control is set to 128 μsec, for example. However, the PWM carrier wave period is 64 μsec on the drum motor 5 side and 128 μsec on the compressor motor side. The control circuit 30 and the inverter circuit 31 constitute an inverter device 99.

  Next, the operation of the drum type washer / dryer provided with the drum motor 5 will be described. When the control circuit 30 energizes the stator windings 5u, 5v, 5w by the inverter circuit 31, an external magnetic field (a magnetic field generated by a current flowing through the stator windings 5u, 5v, 5w) is generated by the permanent magnet of the rotor 52. Acts on 57a and 57b. Then, the magnetization state of the small coke magnet 57b having a small coercive force is demagnetized or increased by the external magnetic field, and as a result, the amount of magnetic flux interlinked with the stator windings 5u, 5v, 5w (interlinkage magnetic flux amount) is increased or decreased. Is done.

  In the washing operation, the control circuit 30 opens the water supply valve 10 to supply water into the water receiving tank 4 and then rotates the drum 7 to perform washing. In this case, the magnetization state of the Samakoba magnet 57b is increased. As a result, the amount of magnetic flux acting on the stator windings 5u, 5v, 5w is large (the magnetic force is strong), so that the characteristics suitable for rotating the drum 7 at high torque and low speed are obtained. However, since the magnetic force when the sumaboba magnet 57b is magnetized to the maximum is about 90% of the magnetic force of the neodymium magnet 57a, there is a slight difference between the two magnetic forces.

  In the dehydration operation, the control circuit 30 opens the drain valve 14 to discharge the water in the water receiving tank 4, and then rotates the drum 7 at a high speed to dehydrate moisture contained in the laundry. In this case, the magnetization state of the sumaboba magnet 57b is demagnetized. As a result, the amount of magnetic flux acting on the stator windings 5u, 5v, 5w is reduced (the magnetic force is weak), so that the drum 7 has characteristics suitable for rotating at a low torque and a high speed. Finally, in the drying operation, the control circuit 30 drives the blower fan 22 and the heat pump 29 and rotates the drum 7 to dry the laundry. In this case, the magnetized state of the sumaboba magnet 57b is increased in preparation for the next washing operation.

  Then, in the state in which the Samacoba magnet 57b is demagnetized, as shown in FIG. 5B, the magnetic flux detected by the Hall sensor 45 at the position of the Samacoba magnet 57b is weakened, so that the pulse width of the sensor signal waveform to be output changes. There is a case. Then, since it is considered that the rotational speed detected based on the edge interval of the sensor signal has temporarily increased, the speed control is likely to be disturbed.

  Next, the operation of this embodiment will be described with reference to FIGS. FIG. 1 is a flowchart showing the contents of control by the control circuit 30 and is executed, for example, at a cycle of 1 msec. The control circuit 30 first refers to the sensor signals Hu, Hv, Hw output from the hall sensors 45u, 45v, 45w, and determines the sensor signals Hu, Hv, Hw of the previous cycle stored in the storage means such as a memory. It is determined whether or not the combination pattern (state) indicated by each level is different from the current combination pattern (step S1). Here, if both patterns are the same (NO), it indicates that there is no change across the edge of any sensor signal that occurs every 60 ° of electrical angle, so after incrementing the hall_cnt variable ( Step S13) The process proceeds to step S8.

  On the other hand, if the sensor pattern in the previous cycle is different from the current pattern in step S1 (YES), both patterns are compared to check the rotation direction of the drum motor 5 and the sensor signal itself. (Step S2). That is, as shown in FIG. 4, the sensor signals Hu, Hv, and Hw have a constant pattern (for example, forward rotation; A → B → C → D) at every electrical angle of 60 ° according to the rotation direction of the drum motor 5. This is because the change is repeated in order of → E → F → A → B →.

If there is no abnormality in step S3 (YES), the rotational speed (ω) of the drum motor 5 at that time is obtained by dividing a predetermined constant by the count value of the hall_cnt variable (step S4), and the rotational speed (ω ) To perform speed control (step S5). That is, the count value of the hall_cnt variable obtained in step S4 indicates how many milliseconds the interval between electrical angles is 60 °. Therefore, if the rotational speed (ω) is obtained in [rpm],
ω = 60 · 1000 / (144 · hall_cnt) [rpm] (1)
It becomes. Note that the rotational speed (ω) in this flowchart is expressed in units of [rpm], but the rotational speed ω shown in the block diagram of the vector control is an angular speed [rad / s].
FIG. 4B shows a state in which the rotational speed (ω) is detected at the timing of each edge of the sensor signals Hu, Hv, and Hw, and the speed and current are controlled so as to follow the target speed ωref. Has been.

  On the other hand, if there is an abnormality in step S3, that is, if the output pattern of the sensor signal corresponding to the rotation direction of the drum motor 5 is not as expected (NO), an abnormality flag is set (step S14). In this case, for example, it is assumed that the Hall sensor 45 has failed, or an abnormality such as a disconnection of the sensor signal transmission line has occurred. Therefore, after the processing of FIG. Abnormal processing such as output of the image or display on the display unit).

FIG. 2 is a flowchart showing the processing content of “speed control” in step S5. This processing is performed in the speed PI control unit 65 in the block diagram of FIG. First, a difference between the speed command value ωref and the rotation speed (ω) obtained in step S4 is obtained as a deviation Omega_dev (step S21). Then, the current integral term is obtained by adding the deviation Omega_dev multiplied by a constant to the integral term of the q-axis current command value used in the previous control (step S22).
Current command value (integral term) ← (Omega_dev x constant) + current command value (integral term) (2)
Subsequently, the current proportional term is obtained by adding the current integral term obtained in step S22 to the deviation Omega_dev multiplied by a constant (step S23).
Current command value (proportional term) ← (Omega_dev x constant) + current command value (integral term) (3)
The q-axis current command value Iqref output from the speed PI control unit 65 is output as the sum of the integral term and the proportional term.

  Reference is again made to FIG. When speed control is performed in step S5, the hall_cnt variable is cleared (step S6) after the count value of the hall_cnt variable is saved as a “save value” (step S7). In the next step S8, it is determined whether or not the hall_cnt variable has exceeded “200” (corresponding to 0.2 s, monitoring time). However, after step S7, it is naturally determined “NO” and the process ends. To do. The above processing flow is when the drum motor 5 rotates normally.

When a sudden fluctuation of the load torque as shown in FIG. 12 occurs, if the control of the drum motor 5 becomes unstable and rotation is about to stop, the edge intervals of the sensor signals Hu, Hv, Hw are extended. . Then, the number of times “NO” is determined in step S1 is increased, and the hall_cnt variable is continuously incremented in step S13. As a result, if the hall_cnt variable exceeds “200” and is determined to be “YES” in step S8, the process proceeds to step S9. In the case where “YES” is determined in step S8, the rotation speed of the drum motor 5
ω = 60 · 1000 / (144 · 200) ≈2.08 [rpm] (4)
This corresponds to a state of rotating at a very low speed.

  In step S9, the value of the current hall_cnt variable is compared with the value of the hall_cnt variable saved in step S6 when the speed control is normal. If the former exceeds the saved value (YES), the process proceeds to step S10. . The determination in step S9 is performed in order to avoid that the second term in the following equation (5) becomes a negative value. If it is determined “NO”, the processing is ended as it is.

When the process proceeds to step S10, it is determined that the speed control is abnormal and the rotation of the drum motor 5 is likely to stop. Therefore, here, the command value (integral term) of the q-axis current used in the calculation in step S22 is determined as follows to increase the energization current amount for the drum motor 5.
Current command value (integral term) ← Current command value (integral term)
+ (Hall_cnt variable-save value) x constant (5)
That is, a value obtained by multiplying the difference between the hall_cnt variable and the saved value by a constant is added. When the current command value (integral term) obtained by the equation (5) exceeds a predetermined maximum value (step S11: YES), the current command value (integral term) is replaced with the maximum value. Restriction is applied (step S12).

  Here, FIG. 3 is a variation example of (a) each sensor signal of the hall sensor 45 (u, v, w), (b) q-axis current command value Iqref, (c) q-axis current Iq. It is a timing chart which shows the process corresponded when it is judged as "YES" in step S9. However, the time for monitoring the period in which the sensor signal does not change (non-change period) shown in (a) is not the image set to 0.2 seconds as in step S8. For example, the “evacuation value” in step S6 is the past. This is a case where a plurality of times are stored, and the average value thereof is set as an appropriate margin α.

  That is, the monitoring time in this case is dynamically set according to the retracted value corresponding to the rotational speed (ω) of the drum motor 5 obtained at the timing when the sensor signals Hu to Hw have changed last time, in other words, at least This corresponds to the next pulse generation interval expected based on the past detection speed (ω) including the immediately preceding value detection speed (ω). Then, as shown in FIG. 3A, when the non-change period becomes longer than {(average value of saved values) + α}, (b) the q-axis current command value Iqref is then processed by steps S10 to S12. (C) The q-axis current Iq increases. As a result, (a) the drum motor 5 rotates normally again.

  Further, in FIG. 3B, the q-axis current command value Iqref is illustrated so as to monotonically increase in an analog manner. This is because the speed control performed by the control circuit 30 according to the flowchart of FIG. 2 is discrete, but as a result of the control, the q-axis current command value Iqref actually output from the speed command output unit 65 is analog. Therefore, the waveform changes continuously as shown in FIG.

As described above, according to this embodiment, the control circuit 30 rotates the rotational speed (ω) of the drum motor 5 at the timing when the sensor signals Hu, Hv, Hw output from the plurality of hall sensors 45u, 45v, 45w change. Is calculated, the current applied to the windings 5u, 5v, 5w of the drum motor 5 is controlled based on the rotational speed (ω), and the speed control is performed, and the state where the sensor signals Hu, Hv, Hw do not change is predetermined. The current amount energized to the windings 5u, 5v, 5w is increased from the current control value if the monitoring time is continued for more than.
With such a configuration, even when the inertia of the drive system is small and the number of changes of the sensor signals Hu, Hv, Hw output from the plurality of Hall sensors 45u, 45v, 45w with respect to one electrical angular period is small, It is possible to detect at an early stage that the speed control of the drum motor 5 has become unstable and increase the rotational speed of the drum motor 5 to return the speed control to a stable state. And by applying to the drum motor 5 that rotationally drives the drum 7 of the washing machine, the rotation of the drum motor 5 stops even when the load torque fluctuates greatly according to the amount and distribution state of the laundry in the drum 7. The operation time can be shortened by reducing the period to perform as much as possible.

Further, the control circuit 30 sets the monitoring time according to the rotational speed (ω) of the drum motor 5 calculated at the timing when the sensor signals Hu, Hv, and Hw have changed at least last time. For example, since the monitoring time is set by adding the margin α to the average value of the rotational speed (ω) calculated continuously several times before the previous time, the rotational speed calculated during the period when the speed control was normally performed The monitoring time can be set appropriately based on (ω), and the state where the speed control becomes unstable can be detected earlier.
Further, in this embodiment, the drum motor 5 having both the neodymium magnet 57a and the Samacoba magnet 57b in the rotor 52 is controlled, so that the magnetic force of the Samacoba magnet 57b decreases during operation. Even when the speed control becomes unstable, the speed control can be restored to a normal state at an early stage, and the lock of the drum motor 5 can be avoided.

(Second embodiment)
9 to 11 show a second embodiment of the present invention. The same parts as those in the first embodiment are denoted by the same reference numerals and the description thereof will be omitted. Hereinafter, different parts will be described. FIG. 9 is a diagram corresponding to FIG. 1, and FIG. 10 is a diagram corresponding to FIG. 5. In the second embodiment, the drum motor 5 used in the control system when the rotation of the drum motor 5 is estimated to stop. The rotation speed (ω) is replaced with a pseudo value to continue the control. In FIG. 9, steps S1 to S6 are executed in the same manner as in the first embodiment, and when a value obtained by multiplying the saved value by a constant (for example, 1.5) is set as a “comparison value” (step S31), a current command value comparison is performed. Variables (see steps S36 and S39) are initialized (step S32). Then, when step S7 is executed, the hall_cnt variable is compared with the comparison value (step S33). If the hall_cnt variable is equal to or smaller than the comparison value (NO), it is determined that the speed control is normal, and the process ends.

  On the other hand, if the hall_cnt variable exceeds the comparison value in step S33 (YES), it is estimated that the rotation speed of the drum motor 5 is decreasing, so the same processing as in steps S4 and S5 is performed (steps S34 and S35). ), A value obtained by adding the saved value to the current comparison value is set as a new comparison value (step S36). In this case, the rotation speed (ω) is set based on the hall_cnt variable incremented in step S13.

  Then, it is determined whether or not the q-axis current command value Iqref determined in step S22 of FIG. 2 has reached the maximum value (step S37). If the maximum value has not been reached (NO), the process is terminated. When the maximum value is reached (YES), the current command value comparison variable is incremented (step S38), and it is determined whether or not the value is “3” or more. If it is less than “3” (NO), the process is terminated as it is, and if it reaches “3” (YES), the drum motor 5 is restarted.

  That is, when the processing of steps S34 to S36 is performed, the rotational speed (ω) of the drum motor 5 is initially set based on the hall_cnt variable as in the case where the speed control is normal, and the comparison value is set in step S31. More than the value to be set is set by the saved value in step S6. When the processes in steps S34 to S36 are repeatedly executed, the rotational speed (ω) is set so as to sequentially decrease based on the hall_cnt variable incremented in step S13. Then, since the speed deviation Omega_dev increases in the process of FIG. 2, the q-axis current command value Iqref gradually increases (see FIGS. 10B and 10C).

  FIG. 10 shows a case where the speed control returns to a normal state as a result of increasing the q-axis current command value Iqref, but FIG. 11 shows a case where “YES” is determined in the step S39. That is, even if the q-axis current command value Iqref is increased, the speed control does not return to the normal state, and when the three control cycles elapse from the time when the q-axis current command value Iqref reaches the maximum value, the current control state is changed. The operation is stopped without continuing, and the drum motor 5 is restarted. The restarting process here is a general restarting process that is performed when the rotation of the drum motor is stopped as in the conventional case.

As described above, according to the second embodiment, the control circuit 30 sets the rotational speed (ω) of the drum motor 5 to a predetermined value when the sensor signals Hu, Hv, Hw do not change for more than the monitoring time. Speed control. Specifically, the predetermined value is set to a speed value based on a hall_cnt variable corresponding to the monitoring time. Therefore, when the rotational speed of the drum motor 5 actually tends to decrease greatly, the rotational speed (ω) is set to a virtual value so that the speed is gradually decreased in terms of control. Will be handled. As a result, it is possible to stabilize the speed control so as not to be directly affected by the occurrence of a significant decrease in speed, and to increase the rotational speed of the drum motor 5 faster.
Further, when three control cycles have elapsed since the q-axis current command value Iqref reached the maximum value (rotation abnormality determination), the control circuit 30 stops the current control state without continuing any further, and the drum motor Therefore, the operation of the washing machine can be continued while avoiding the rotation abnormality determination → the restart process as much as possible.

The present invention is not limited to the embodiments described above or shown in the drawings, and the following modifications or expansions are possible.
In the first embodiment, the monitoring time shown in the timing chart of FIG. 3 does not necessarily need to take the average of the saved values for a plurality of past times, and if the variation α can be absorbed by the margin α, only the immediately preceding saved value is obtained. May be used. Further, it may be set similarly to step S31 of the second embodiment.
In step S39 of the second embodiment, the number compared with the current command value comparison variable may be other than “3”.
The motor is not limited to the drum motor 5 in which the Samakoba magnet 57b is mixed in the rotor, but may be a motor using only the neodymium magnet 57a, for example.

An alnico magnet may be used as the low coercive force permanent magnet.
The position sensor is not limited to the hall sensor 45 but may be an optical sensor.
Current control is not limited to performing PI control. Therefore, when increasing the amount of current flowing to the motor, for example, a predetermined value may be added to the current command value.
You may apply to the vertical washing machine which rotates a pulsator, without restricting to a drum type washing machine.
Further, the present invention is not limited to a washing machine, and can be applied to any motor control system in which the inertia of the drive system is small and the number of changes in sensor signals output from a plurality of rotational position sensors is small.

  In the drawings, 5 is a drum motor, 5u to 5w are stator windings, 7 is a drum (rotary tank), 30 is a control circuit (speed control means), 45 is a hall sensor (rotational position sensor), 52 is a rotor, 57a is A neodymium magnet (high coercive force permanent magnet), 57b indicates a samarium-cobalt magnet (low coercive force permanent magnet).

Claims (8)

A plurality of rotational position sensors for detecting the rotor position of the motor;
During the rotation of the motor, the rotation speed of the motor is calculated at a timing when sensor signals output from the plurality of rotation position sensors change, and a current flowing through the winding of the motor is calculated based on the calculated rotation speed. Speed control means is provided for controlling the speed, and when the state in which the sensor signal does not change continues for a predetermined monitoring time or longer, the speed control means for increasing the amount of current to be supplied to the winding of the motor from the current control value. A motor control device.   The motor control device according to claim 1, wherein the speed control unit sets the monitoring time according to at least a rotation speed of the motor calculated at a timing when the sensor signal has changed last time.   3. The motor control device according to claim 2, wherein the speed control unit sets the monitoring time according to an average value of the rotation speeds of the motor continuously calculated a plurality of times before the previous time.   4. The speed control unit according to claim 1, wherein when the sensor signal does not change for more than the monitoring time, the speed control means sets the rotation speed of the motor to a predetermined value and performs speed control. The motor control device described in 1.   5. The motor control device according to claim 4, wherein the speed control means sets the predetermined value to a speed value corresponding to the monitoring time.   The speed control means performs a rotation abnormality determination of the motor after the current amount reaches a predetermined maximum value as a result of increasing the amount of current flowing to the winding of the motor. The motor control device according to claim 1.   2. The motor having both a high coercive force permanent magnet and a low coercive force permanent magnet whose magnetic force can be changed by a magnetic field generated by a stator winding is controlled. 7. The motor control device according to any one of 6 to 6. A motor for generating a rotational driving force for performing washing and dehydration;
A washing machine comprising the motor control device according to any one of claims 1 to 7.

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