JP2007236068A - Motor control device, motor control method and washing machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To highly accurately detect a resistance value of an armature wining during driving a motor. <P>SOLUTION: A motor control device estimates the rotation position and rotation speed of a rotor on the basis of a motor current, a motor voltage and a motor circuit constant to control a vector. The motor control device is provided with a rotation position detecting means for detecting that the rotor is at a specific rotation position outputting a synchronous pulse, and the resistance value of the armature winding as one of motor circuit constants is adjusted so that the estimated rotation position at the point when the rotation position detecting means has output the synchronous pulse may match the specific rotation position of the rotor. A resistance value upon matching by adjustment is treated as the resistance value of the armature winding at that point. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a motor control device that drives and controls a motor based on a rotor position estimated using a motor constant, a motor current, and a motor voltage, a motor control method, and a washing machine using the motor control device.

  In recent years, the adoption of motor control devices that perform vector control of DD (Direct Drive) motors is increasing in washing machines. Washing machines that employ vector control have the effects of reducing power consumption, vibration during operation, and noise reduction.

  In order to perform vector control of the motor, it is necessary to accurately detect the rotational position of the rotor. There are two methods for detecting the rotational position of the rotor: a method in which a rotational position sensor is attached to the motor for detection, and a sensorless method in which the motor voltage, current value and motor circuit constant are estimated without using a sensor.

  In the method using the sensor, an encoder or a hall sensor is used as the rotational position sensor. The rotational position sensor has an advantage that the rotor position can be accurately detected even when the motor rotational speed is low. However, the rotational position sensor may be misaligned due to vibration and detection accuracy may deteriorate. If the detection accuracy of the rotor position deteriorates, the effect of vector control, in which the armature current is separated into a torque direction component (q-axis current) and a magnetic flux axis direction component (d-axis current) and controlled independently, is significantly reduced. The As a result, problems such as reduction in motor efficiency and increase in vibration and noise occur.

  The sensorless method estimates the rotor position using position information included in the voltage and current of the motor. This method has a problem in detection accuracy in a low-speed region where the induced voltage is low, but does not cause a problem of positional deviation like the rotational position sensor. In addition, the rotation position sensor, its wiring, and the advantage that maintenance is not required are increasing the use in washing machines.

  In addition to the motor current and voltage, motor circuit constants are necessary for the estimation calculation of the rotor position by the sensorless method. One of the necessary circuit constants is the resistance value of the armature winding. The resistance value of the armature winding varies with temperature. Therefore, in order to accurately estimate the rotor position, it is necessary to accurately grasp the resistance value corresponding to the temperature at that time. The resistance value at each temperature can be grasped in advance by experiments, but even if the value is known, it is necessary to detect the winding temperature at that time in order to know the resistance value. However, its detection is not easy. For this reason, there is a need for a method for accurately detecting the winding resistance value of the rotating armature without attaching a sensor for detecting the winding temperature.

There exists patent document 1 as a prior art. In this detection method, constant voltage control is performed before or at the start of the motor, a constant voltage is applied to the armature winding, and the winding resistance value is calculated from the current value at that time. The detection by this method has an advantage that the resistance value at the current temperature can be detected. However, since this method is performed in a state where the rotor is stopped, positioning time for stopping is required and there is a problem that power consumption increases due to a current flowing for detection.
Japanese Patent Application No. 2004-327871 Japanese Patent Application Laid-Open No. 61-262084

  The present invention has been made to solve such problems of the prior art, and the problem is that the motor control is capable of accurately detecting the resistance value of the armature winding at the time during operation of the motor. It is providing a device, a motor control method, and a washing machine using them.

  The invention according to claim 1 for solving the above-mentioned problem is that a current flowing through a three-phase permanent magnet motor having a permanent magnet provided on a rotor is converted into a d-axis current parallel to the magnetic flux produced by the permanent magnet and q orthogonal thereto. It is separated into shaft currents, and these current components are independently controlled so as to match each current command value determined to match the motor rotation speed with the command value, and the rotational position of the rotor necessary for the control In the motor control device used for the above control by estimating the motor speed and the motor speed based on the motor current, motor voltage, and motor circuit constants, and outputting a synchronization pulse by detecting that the rotor has reached a specific rotation position Position detecting means and one of the motor circuit constants so that the estimated rotational position value at the time when the rotational position detecting means outputs the synchronization pulse matches the value of the specific rotational position. A motor control device, further comprising: winding resistance estimating means for adjusting a resistance value of the armature winding and estimating a resistance value at the time of matching with a resistance value of the armature winding at that time. is there.

  According to the motor control device having such a configuration, the resistance value of the armature winding at the armature winding temperature at that time can be detected while the motor is driven to rotate. Since the detected winding resistance value is immediately used for the estimation calculation of the angular velocity and the rotational position, the accuracy of the angular velocity estimation and the rotational position estimation is improved and the motor control accuracy by vector control is improved. As a result, problems such as a reduction in motor efficiency and an increase in vibration and noise do not occur.

  Further, the invention according to claim 2 is the motor control device according to claim 1, wherein the winding resistance estimating means is an operating state in which the d-axis current is zero as the value of the specific rotational position of the rotor. In the motor control apparatus, the estimated specific rotational position value, which is the estimated rotational position value at the time when the rotational position detecting means outputs the synchronization pulse, is used.

  In the operation where the d-axis current is zero, the angular velocity and the rotational position of the rotor can be estimated without being affected by the resistance value of the armature winding (and hence without being influenced by the winding temperature). For this reason, since the accuracy of the estimated rotational position is increased, the value may be treated as the value of the specific rotational position. In this way, the value of the specific rotation position can be easily and accurately known.

  According to a third aspect of the invention, there is provided the motor control device according to the first or second aspect, wherein the winding resistance estimating means is configured to detect the armature when the estimated rotational speed variation is within a predetermined range. A motor control device that estimates a resistance value of a winding.

  In the state where the rotation speed is fluctuating, the estimation accuracy of the winding resistance value is deteriorated. Therefore, if the estimation is performed in a state where the fluctuation of the rotation speed is within the predetermined range, the estimation accuracy can be improved.

  According to a fourth aspect of the present invention, there is provided the motor control device according to the first or second aspect, wherein the winding resistance estimating means is configured such that the armature winding is configured when the fluctuation of the q-axis current is within a predetermined range. A motor control device characterized by estimating a resistance value of a wire.

  In the state where the q-axis current is fluctuating, the estimation accuracy of the winding resistance value is deteriorated. Therefore, if the estimation is performed in a state where the fluctuation of the q-axis current is within the predetermined range, the estimation accuracy can be improved.

  According to a fifth aspect of the present invention, in the motor control device according to the second aspect, the winding resistance estimating means stores the value of the estimated specific rotational position for each q-axis current range, and In the state where the rotational speed is controlled using the estimated rotational position and rotational speed, the estimated rotational position when the rotational position detecting means outputs the synchronization pulse is the q-axis to which the q-axis current belongs. The resistance value of the armature winding used for the estimation is adjusted so as to match the value of the estimated specific rotational position stored corresponding to the current range, and the resistance value at the time of matching is determined as the armature winding at that time It is a motor control device characterized by estimating the resistance value of the motor.

  In operation with d-axis current set to zero, the estimated values of angular velocity and rotational position are affected by q-axis inductance. The value of the q-axis inductance varies slightly depending on the magnitude of the q-axis current. Therefore, as in this configuration, the estimated specific rotational position value is stored for each q-axis current range, and when estimating the winding resistance value of the armature winding, the estimated specific value corresponding to the q-axis current at that time is stored. By using the value of the rotational position, it is possible to improve the estimation accuracy of the winding resistance value.

A sixth aspect of the present invention is the motor control apparatus according to the first or second aspect, wherein a hall sensor is used as the rotational position detecting means.
If the Hall sensor is used, it can be easily detected that the rotor has reached the specific rotation position, and the synchronization pulse can be easily output.

  The invention according to claim 7 is a washing machine using the motor control device according to any one of claims 1 to 6.

  Such a washing machine improves the motor control accuracy by vector control because the winding resistance value of the motor is accurately estimated. As a result, problems such as a reduction in motor efficiency and an increase in vibration and noise do not occur.

  In the invention according to claim 8, the current flowing through the three-phase permanent magnet motor in which the permanent magnet is provided in the rotor is separated into the d-axis current parallel to the magnetic flux generated by the permanent magnet and the q-axis current orthogonal thereto. In addition, the current components are independently controlled so as to match the respective current command values determined to match the motor rotation speed with the command value, and the rotation position and rotation speed of the rotor necessary for the control are determined. A motor control method that is used for the above control based on a motor current, a motor voltage, and a motor circuit constant, and that the rotor is in a specific rotation position in an operation state where the d-axis current is zero. Detecting by the detecting means and storing the value of the estimated rotational position at that time as the value of the estimated specific rotational position; and detecting that the rotor has reached the specific rotational position by the rotational position detecting means When the resistance value of the armature winding, which is one of the motor circuit constants, is adjusted so that the value of the estimated rotational position at the time point coincides with the stored value of the estimated specific rotational position. And estimating the resistance value of the armature winding at that time as the resistance value of the armature winding.

  According to such a motor control method, an effect similar to the effect of the invention described in claim 1 can be obtained.

  Hereinafter, an embodiment in which a motor control device and a motor control method according to the present invention are applied to a drum type washing machine will be described with reference to the drawings. First, the overall configuration of the drum type washing machine will be described with reference to FIG.

  On the front part of the outer box 2 that forms the outer shell of the drum-type washing machine 1, a door 3 is provided at the center, and an operation panel having a number of switches and a display part (none of which are shown) at the top. 4 is attached. The door 3 opens and closes a laundry loading / unloading port 5 formed in the front center portion of the outer box 2. A cylindrical water tank 6 is disposed inside the outer box 2. The water tank 6 is arranged in a horizontal axis shape in which the axial direction is the front-rear direction (left-right direction in FIG. 1) and in an upwardly inclined shape, and is supported by an elastic support device 7. A cylindrical rotating drum 8 is disposed coaxially with the water tank 6 inside the water tank 6. This rotating drum 8 functions as a tank shared for dehydration and drying in addition to washing, and has a large number of small holes 9 formed in almost the entire region of the body (only a part is shown in FIG. 1). A plurality of baffles 10 are provided on the inner periphery of the unit (only one is shown in FIG. 1).

  The water tub 6 and the rotating drum 8 are provided with openings 11 and 12 for loading and unloading the laundry on the front surface. The opening 11 of the water tub 6 is connected to the laundry entrance / exit 5 in a watertight manner by a bellows 13, and the opening 12 of the rotating drum 8 faces the opening 11 of the water tub 6. A balance ring 14 is provided around the opening 12 of the rotary drum 8.

  A motor 15 that rotationally drives the rotary drum 8 is attached to the back surface of the water tank 6. The motor 15 is an outer rotor type brushless permanent magnet motor, and its stator 16 is fixed to the outer peripheral portion of a bearing housing 17 attached to the central portion of the back portion of the water tank 6. A three-phase winding 18 (corresponding to a stator winding) is wound around the stator 16.

  The rotor 19 of the motor 15 is arranged so as to cover the stator 16 from the outside. The rotating shaft 20 attached to the center portion is rotatably supported by a bearing 21 fixed to the bearing housing 17. The front end portion of the rotary shaft 20 protruding from the bearing housing 17 is connected to the central portion of the back portion of the rotary drum 8. That is, when the rotor 19 of the motor 15 is rotated, the rotating drum 8 is also rotated integrally with the rotor 19 (so-called direct drive system), and a rotational force is applied to the laundry stored in the rotating drum 8. The washing operation, the rinsing operation, and the dehydration operation are performed.

  A water reservoir 22 is provided on the lower surface of the water tank 6, and a heater 23 for heating the washing water is disposed inside the water reservoir 22. A drain hose 25 is connected to the rear of the water reservoir 22 via a drain valve 24.

  A hot air generator 26 is attached to the upper part of the water tank 6, and a heat exchanger 27 is attached to the back thereof. The hot air generator 26 includes a warm air heater 29 disposed in a case 28, a fan 31 disposed in a casing 30, and a fan motor 33 that rotationally drives the fan 31 via a belt transmission mechanism 32. It is. The case 28 and the casing 30 are in communication. A duct 34 is connected to the front portion of the case 28, and the front end portion of the duct 34 projects to the front portion in the water tank 6 and faces the opening 12 of the rotating drum 8.

  Hot air is generated by the hot air heater 29 and the fan 31, and the hot air is supplied into the rotary drum 8 through the duct 34. The warm air supplied into the rotating drum 8 heats the laundry in the rotating drum 8 and removes moisture, and is discharged to the heat exchanger 27 side.

  The heat exchanger 27 is water-cooled, and the upper part communicates with the inside of the casing 30 and the lower part communicates with the inside of the water tank 6. Water is poured from the upper part, and when the water flows down, water vapor in the air passing through the inside is cooled, condensed and dehumidified. The air that has passed through the heat exchanger 27 returns to the hot air generator 26 again, and is warmed and circulated.

  FIG. 2 is a block diagram showing the configuration of the motor control device 40 of this embodiment that performs vector control of the rotation of the motor 15. Vector control is a method of controlling the magnetic flux and the generated torque by separating the current flowing through the armature winding into the magnetic flux direction of the permanent magnet, which is a field, and the direction orthogonal thereto and adjusting them independently. For the current control, a current value represented by a rotating coordinate system rotating with the rotor 19, a so-called dq coordinate system is used. Here, the d-axis is a magnetic flux direction produced by the permanent magnet attached to the rotor 19, and the q-axis is a direction orthogonal to the d-axis (a direction advanced by π / 2 in the rotation direction by an electrical angle). The q-axis current Iq, which is the q-axis component of the current flowing through the armature winding, is a component that generates rotational torque and is also referred to as torque component current. The other d-axis component, d-axis current Id, is a component that produces magnetic flux and is also called a magnetization component current.

  The motor control device 40 includes a current control circuit 41, a rotational position estimation circuit 42, a current command value determination circuit 43, and a winding resistance estimation circuit (corresponding to winding resistance estimation means) 44. The current control circuit 41 converts the values of the d-axis current Id and the q-axis current Iq that actually flow through the motor 15 into the d-axis current command value Idr and the q-axis current command value Iqr output from the current command value determination circuit 43. These circuits are controlled to match each other. The current control circuit 41 includes subtractors 46 and 47, proportional integrators 48 and 49, a dq / αβ coordinate converter 51, an αβ / UVW coordinate converter 52, a PWM formation circuit 53, an inverter circuit 54, and a current detection circuit 56. . The current detection circuit 56 is a circuit that detects the d-axis current Id and the q-axis current Iq of the current actually flowing through the motor 15.

  The current detection circuit 56 includes a UVW current detection circuit 57, a UVW / αβ coordinate converter 58, and an αβ / dq coordinate converter 59. The UVW current detection circuit 57 is a circuit that detects currents Iu, Iv, and Iw that flow in each phase (U phase, V phase, and W phase) of the motor 15. The UVW current detection circuit 57 is based on the voltage across the three shunt resistors 64 connected between the ground-side switching element 62 of the three-type half-bridge circuit 61 provided in the inverter circuit 54 and the ground potential GND. Iu, Iv, and Iw are detected. As a circuit configuration of the UVW current detection circuit 57, for example, a circuit described in detail in Patent Document 2 is used.

  The detected currents Iu, Iv, and Iw are converted into equivalent two-phase currents Iα and Iβ by the UVW / αβ coordinate converter 58. The converted two-phase currents Iα and Iβ are further converted by an αβ / dq coordinate converter 59 to calculate a d-axis current Id and a q-axis current Iq. α and β are coordinate axes of a biaxial coordinate system fixed to the stator of the motor 15. For the calculation of the coordinate transformation in the αβ / dq coordinate converter 49, a rotor rotational position estimated value (estimated value of phase difference between α axis and d axis) θe described later is used.

  The d-axis current Id and the q-axis current Iq calculated in this way are compared with the d-axis current command value Idr and the q-axis current command value Iqr output from the current command value determination circuit 43 by the subtraction circuits 46 and 47, respectively. Then, current deviations ΔId and ΔIq are calculated. The current deviations ΔId and ΔIq are proportionally integrated by proportional integrators 48 and 49, and output voltage command values Vd and Vq expressed in the dq coordinate system are calculated. The output voltage command values Vd and Vq are converted into values expressed in the α-β coordinate system by the dq / αβ coordinate converter 51, and further, the αβ / UVW coordinate converter 52 converts the phase voltage command values Vu, Converted to Vv and Vw. Note that the rotor rotational position estimation value θe, which will be described later, is also used for calculation of coordinate conversion in the dq / αβ coordinate converter 51.

  The phase voltage command values Vu, Vv, and Vw are input to the PWM forming circuit 53, and a pulse drive modulated gate drive signal for supplying a voltage that matches the command value is formed. The inverter circuit 54 is a known inverter circuit composed of three half bridge circuits 61, and is supplied with a DC voltage from a DC power supply circuit (not shown). The gate drive signal formed by the PWM forming circuit 53 is applied to the gates of the switching elements 62, 63, etc. constituting each half bridge circuit 61, and thereby PWM modulated in accordance with the phase voltage command values Vu, Vv, Vw. A three-phase AC voltage is generated and applied to the armature winding.

  Under such a configuration, feedback control is performed by proportional integration calculation by the subtraction circuits 46 and 47 and the proportional integrators 48 and 49, and the d-axis current Id and the q-axis current Iq are d-axis current command values Idr and q, respectively. Adjustment is made to match the shaft current command value Iqr.

  In the current control process as described above, the value of the rotational position θ of the rotor is required when the αβ / dq coordinate converter 59 and the dq / αβ coordinate converter 51 perform coordinate conversion. The value of the rotational position θ can be detected by attaching a rotational position sensor such as an encoder to the motor 15, but there are many problems in view of maintenance and cost. In this embodiment, such a rotational position sensor is not used, but a method of estimating the rotational position θ without using a sensor is employed.

  The rotational position estimation circuit 42 is a circuit that estimates an estimated value θe of the rotational position θ of the rotor and an estimated value ωe of the angular velocity ω. The rotational position estimation circuit 42 includes an induced voltage estimation circuit 71, a proportional integrator 72, and an integrator 73. The induced voltage estimation circuit 71 receives the d-axis current Id, the q-axis current Iq, the d-axis output voltage command value Vd, and the rotor angular velocity estimation value ωe. Further, the induced voltage estimation circuit 71 stores values of d-axis inductance Ld, q-axis inductance Lq, and winding resistance value R of the armature winding, which are circuit constants of the motor 15.

The induced voltage estimation circuit 71 uses these input values and circuit constants to calculate the induced voltage estimated value Ed in the d-axis direction by the following equation.
Ed = Vd-R.Id-Ld.p.Id + .omega.e.Lq.Iq (1) where p is a differential operator. As the value of Vd, the voltage value actually applied to the motor 15 should be used, but since this value matches the voltage command value Vd output by the proportional integrator 48, that value is used.

  The induced voltage estimated value Ed in the d-axis direction thus calculated is input to the proportional integrator 72 and subjected to proportional integration calculation, and the result is output as the estimated angular velocity value ωe of the rotor. The angular velocity estimated value ωe is integrated by the integrator 73, and the value is output as the rotational position estimated value θe.

  The rotational position estimation value θe is used for coordinate conversion in the αβ / dq coordinate converter 59 and the dq / αβ coordinate converter 51 as described above. The estimated angular velocity value ωe is given to the induced voltage estimation circuit 71 and used for calculation of the induced voltage estimated value Ed according to the equation (1). The estimated angular velocity value ωe is also given to the current command value determination circuit 43.

  By the way, ωe used in the calculation of the right side of the equation (1) is an estimated value of the rotor angular velocity and not the actual angular velocity ω. Further, the d-axis current Id and q-axis current Iq on the right side of the equation (1) are values calculated using the rotational position estimated value θe, and the rotational position estimated value θe itself also integrates the angular velocity estimated value ωe. This is the value obtained by Further, the d-axis output voltage command value Vd on the right side of the equation (1) and the q-axis output voltage command value Vq not appearing in the equation (1) are also used for each phase voltage command using the rotational position estimated value θe. The values are converted to Vu, Vv, and Vw. Then, a voltage is generated in the inverter circuit 54 based on the voltage command value, and is given to the armature winding. That is, all variables other than the circuit constants in the equation (1) are affected by the estimated angular velocity value ωe.

  Ed on the left side of equation (1) indicates that the estimated angular velocity value ωe matches the actual angular velocity ω, and the estimated rotational position value θe is also equal to the rotational position of the rotor (the phase difference between the α axis and the d axis). If it does, it should be zero. That the value does not become zero means that the estimated angular velocity value ωe and the estimated rotational position value θe used in the calculation have an error with respect to the actual values.

  In other words, when the angular velocity estimated value ωe and the rotational position estimated value θe calculated therefrom are adjusted so that the value of Ed calculated on the right side of the equation (1) becomes zero, The estimated angular velocity value ωe and the rotational position estimated value θe are equal to the actual angular velocity ω and the rotational position θ. The proportional integrator 72 adjusts the estimated induced voltage Ed in the d-axis direction to zero. When the induced voltage estimated value Ed converges to zero by the adjusting operation of the proportional integrator 72, the angular velocity estimated value ωe, which is the output of the proportional integrator 72 at that time, becomes a value that matches the actual angular velocity ω. In the present embodiment, by using the induced voltage estimation circuit 71 that performs such calculation and adjustment operation, the actual angular velocity ω of the rotor and the estimated angular velocity ωe that matches the value of the rotor position θ without using the rotational position sensor are obtained. The rotational position estimated value θe is obtained.

  The rotational position estimation value θe estimated by the rotational position estimation circuit 42 is given to the dq / αβ coordinate converter 51, the αβ / dq coordinate converter 59, and the winding resistance estimation circuit 44. Further, the estimated angular velocity value ωe is given to the current command value determining circuit 43, the winding resistance estimating circuit 44, and the induced voltage estimating circuit 71.

  The current command value determination circuit 43 is a circuit that outputs a d-axis current command value Idr and a q-axis current command value Iqr. The d-axis current command value Idr and the q-axis current command value Iqr are used to match the angular velocity (corresponding to the rotational speed) ω of the rotor with the angular velocity command value (corresponding to the rotational speed command value) ωr input from the outside. Current command value. The current command value determination circuit 43 includes a subtractor 75, a proportional integrator 76, and a dq distributor 77.

  The subtractor 75 calculates a deviation Δω between the angular velocity command value ωr output from the external microcomputer 80 and the estimated angular velocity value ωe. The microcomputer 80 is for overall control of the overall operation of the drum type washing machine 1. The microcomputer 80 outputs an angular velocity command value ωr corresponding to the process of the washing machine at that time to the subtractor 75 in accordance with an instruction from the operator through the operation panel 4. The deviation Δω is subjected to proportional integration calculation by the proportional integrator 76, and the calculation result is output to the dq distributor 77. The dq distributor 77 distributes the calculation result to the d-axis current command value Idr and the q-axis current command value Iqr and outputs the result. The distribution method is instructed by the microcomputer 80. For example, in the “washing process”, the d-axis current command value Idr is set to zero, and the calculation result of the proportional integrator 76 is output as it is as the q-axis current command value Iqr. In the “dehydration process”, the d-axis current command value Idr is set to a negative value in order to perform the flux weakening control, and a value proportional to the calculation result is output as the q-axis current command value Iqr.

  The d-axis current command value Idr and the q-axis current command value Iqr distributed in this way are given to the current control circuit 41. As described above, the d-axis current Id and the q-axis current Iq of the motor 15 are controlled so as to coincide with those command values. The angular velocity estimation value ωe as a result of such control is fed back to the subtractor 75. The proportional integrator 76 converges the deviation Δω to zero by a proportional integration calculation. As a result, the estimated angular velocity value ωe coincides with the angular velocity command value ωr.

  As described above, the motor control device 40 has a so-called speed servo type configuration in which the speed control loop is provided outside the current minor loop. At this time, the value ωe estimated by the rotational position estimating circuit 42 is used as the value of the angular velocity ω of the rotor necessary for the speed servo. The rotational position estimation circuit 42 calculates and outputs an estimated angular velocity value ωe that matches the actual angular velocity ω. Thus, the actual angular velocity ω of the motor 15 is controlled to a value that matches the angular velocity command value ωr output from the microcomputer 80.

  By the way, in order to make the actual angular velocity ω of the motor 15 coincide with the angular velocity command value ωr with high accuracy, the estimated angular velocity value ωe estimated by the rotational position estimation circuit 42 needs to coincide with the actual angular velocity ω with high accuracy. . The rotational position estimating circuit 42 estimates the actual angular velocity ω by controlling the induced voltage estimated value Ed in the d-axis direction calculated by the equation (1) to be zero as described above. Therefore, in order to increase the estimation accuracy of the estimated angular velocity value ωe, it is necessary to increase the accuracy of Ed calculated by the equation (1).

  Equation (1) includes three circuit constants, d-axis inductance Ld, q-axis inductance Lq, and winding resistance value R. Of these, the winding resistance value R varies considerably with temperature. Therefore, in order to increase the accuracy of Ed, it is important to use a winding resistance value corresponding to the winding temperature at that time. The motor control device 40 of the present embodiment is that the winding resistance value R at that time is detected during the driving of the motor 15 and used for the calculation of the equation (1). In order to detect the winding resistance value R without using a sensor, a winding resistance estimation circuit 44 is provided.

  The winding resistance estimation circuit 44 receives an angular velocity estimation value ωe, a rotational position estimation value θe, a q-axis current Iq, and a synchronization pulse P that informs that the rotor is at a specific rotational position θa. In order to output this synchronization pulse P, a rotational position sensor (corresponding to rotational position detection means) 82 is attached to the motor 15 (note that the winding resistance estimation circuit 44 and the rotational position detection sensor 82 are connected to the winding resistance. It corresponds to the estimation means.) The rotational position sensor 82 is a sensor that outputs a synchronization pulse P when the rotor reaches a specific rotational position (specific electrical angle) θa. As such a rotational position sensor 82, a Hall sensor or an encoder can be used.

  Next, a method for estimating the winding resistance value R will be described with reference to the control flow shown in FIG. The control flow in FIG. 3 is a flow executed by the winding resistance estimation circuit 44. In the first step S1, it is checked whether the angular velocity estimated value ωe is larger than a predetermined angular velocity ωk. This is because it is difficult to accurately estimate the winding resistance value R in a state where the rotational speed of the rotor is low, and the estimation is performed at a certain rotational speed or higher.

  When the angular velocity estimated value ωe is larger than the predetermined angular velocity ωk, the process proceeds to step S2. In step S2, it is checked whether the fluctuation range of the angular velocity estimated value ωe is within a predetermined value. Such a check is performed because accurate estimation is impossible unless the angular velocity estimation value ωe is stable to some extent. Whether or not the fluctuation range of the angular velocity estimated value ωe is within a predetermined value is determined by sampling the angular velocity estimated value ωe several times in a short cycle (for example, a cycle of 10 to 20 msec), and all the values are determined. Judgment is made based on whether or not it falls within a predetermined allowable fluctuation range.

  If the fluctuation range of the estimated angular velocity value ωe is within a predetermined value, the process proceeds to step S3. In step S3, the process waits for the synchronization pulse P to be input from the rotational position sensor 82. As described above, the rotational position sensor 82 outputs the synchronization pulse P when the rotational position of the rotor reaches the specific rotational position θa. That is, at the moment when the synchronization pulse P is output, the actual rotational position θ of the rotor is θa. Therefore, if the value of the estimated angular velocity value ωe at the moment when the synchronization pulse P is output coincides with θa, the rotational position of the rotor is accurately estimated. If the number of times speed at that time is stable, the estimated angular speed value ωe accurately estimates the actual angular speed ω.

  If the synchronization pulse P is received in step S3, the process proceeds to step S4. In step S4, it is determined whether or not the difference | θe−θa | between the estimated angular velocity value ωe estimated by the rotational position estimation circuit 42 and the specific rotational position θa detected by the rotational position sensor 82 is within a predetermined error Δθk. If the difference | θe−θa | is within the predetermined error Δθk, it is considered that the rotational position θ is correctly estimated. Therefore, Δθk is a small value.

  If the difference | θe−θa | is within a predetermined error Δθk, it can be considered that the calculation accuracy of Ed by the equation (1) is also high. If the calculation accuracy of the equation (1) is high, the winding resistance value R used in the equation (1) is also correct, and it can be considered that the value matches the resistance value at the winding temperature at that time. Therefore, if the difference is within Δθk (step S4: YES), there is no need to correct the winding resistance value R used in the calculation, and the process returns to step S1 without doing anything.

  If the difference | θe−θa | exceeds the predetermined error Δθk in step S4, it is determined that the estimation accuracy of the rotational position θ is insufficient, and the process proceeds to step S5. In steps S5 to S7, the resistance value R of the winding is corrected in order to increase the estimation accuracy. First, in step S5, the magnitude of the estimated angular velocity value ωe and the specific rotational position θa at the moment when the synchronization pulse P is output is compared.

  If the estimated angular velocity value ωe is larger, the process proceeds to step S6, and a value obtained by adding a minute value ΔR to the current resistance value R is set as a new resistance value R. On the other hand, if the estimated angular velocity value ωe is smaller, the process proceeds to step S7, and a value obtained by subtracting a minute value ΔR from the current resistance value R is set as a new resistance value R. The induced voltage estimation circuit 71 transmits an instruction to add or subtract ΔR to the currently used resistance value R, and corrects the resistance value R used for estimation. Thereafter, in step S8, the process waits for a minute time Δt and returns to step S1. The reason for waiting for the minute time Δt is to wait until the estimation using the resistance value R after the change is settled.

  As described above, when the estimated value of the angular velocity ωe at the moment when the rotor reaches the specific rotational position θa does not coincide with θa, a slight correction is made to the resistance value R of the winding in the direction approaching θa. . Then, by repeating the correction operation, the estimated angular velocity value ωe at the moment when the rotor reaches the specific rotational position θa is focused on θa. The resistance value R when converged represents the resistance value at that time (corresponding to the winding temperature).

  The motor control device 40 of the present embodiment estimates the resistance value R of the winding at that time by the configuration and control flow as described above. The estimation calculation can be executed at any time as long as the rotational speed is a certain value or more and is stable to some extent. That is, it has a great advantage that it can be estimated in a state where the washing machine is washing. Then, the resistance value R at that time estimated as described above is immediately used for the estimation calculation of the angular velocity ω and the rotational position θ. Thereby, the accuracy of the estimated angular velocity value ωe and the estimated rotational position value θe is improved, and the effect of improving the control accuracy of the motor 15 by vector control is obtained. As a result, problems such as a reduction in motor efficiency and an increase in vibration and noise do not occur.

  Here, a method of knowing the value of the specific rotational position (specific electrical angle) θa of the rotor when the rotational position sensor 82 outputs the synchronization pulse P will be described. This specific rotational position θa is a value determined by the mounting position and mounting method of the rotational position sensor 82 such as a hall sensor or an encoder to the motor 15. Therefore, the value θa can be known from the mechanical dimension of the motor 15, for example, the dimension on the mechanical structure drawing. In addition to reading from the drawing, it is also possible to actually measure and know the angle at the moment when the synchronization pulse P is output.

  However, when the number of magnetic poles of the rotor is large, the mechanical angle corresponding to the electrical angle 2π is a small value. For this reason, the value of the specific rotation position read from the drawing may not match the rotation position at the moment when the synchronization pulse P is actually output. As a countermeasure, instead of the method of reading from the drawing, the value of θa may be detected electrically as follows.

The equation (1) is as follows when the value of the d-axis current Id is zero.
Ed = Vd + ωe · Lq · Iq (2) In other words, the value of the induced voltage estimated value Ed in the d-axis direction is calculated irrespective of the winding resistance value R. That is, the angular velocity ω and the rotational position θ can be estimated without being affected by the winding temperature.

  According to the equation (2), the value of the estimated angular velocity value ωe at the moment when the synchronization pulse P is output under the operation where the value of the d-axis current Id is zero is the value of the q-axis inductance Lq. It can be considered that it coincides with the specific rotation position θa. The value of the q-axis inductance Lq can be grasped with relatively high accuracy by calculation or measurement, and is hardly affected by temperature. Therefore, in the operating state where the value of the d-axis current Id is zero, the angular velocity ω and the rotational position θ can be estimated with high accuracy.

  For this reason, the operation is performed with the d-axis current Id being zero, and the value of the rotational position θ (corresponding to the value of the estimated specific rotational position) read at the moment when the synchronization pulse P is output in that state is the specific rotation. You may make it handle as a value of position (theta) a. When such a method is adopted, the rotational position sensor 82 can be attached to the motor 15 at any position, which is convenient.

  As a modification of the method of detecting the value of the specific rotational position θa by the operation with the d-axis current Id being zero, the q-axis current Iq at the time of detection is changed in several steps, The specific rotation position θa detected for each range may be stored. This is because the value of the q-axis inductance Lq slightly changes depending on the value of the q-axis current Iq, and the value of the detected specific rotational position θa is slightly different.

  When the specific rotational position θa is stored for each range of the q-axis current Iq as described above, the specific rotational position θa corresponding to the value of the q-axis current Iq at that time is read in steps S4 and S5 of the control flow of FIG. Used for calculation. In this way, the influence of the value of the q-axis current Iq can be reduced, and the estimation accuracy of the winding resistance value R can be further increased.

  Further, in step S2 of the control flow of FIG. 3, it is determined that the fluctuation range of the angular velocity estimated value ωe is within a predetermined value, but the fluctuation range of the q-axis current Iq is within the predetermined value instead of the angular velocity estimated value ωe. You may determine that there is. This is because when the fluctuation range of the q-axis current Iq is large, the estimation accuracy of the winding resistance value R is poor, and when the fluctuation range of the q-axis current Iq is small, the fluctuation of the estimated angular velocity value ωe is almost always small.

It is a structural example of a drum type washing machine. It is an example of composition of a motor control device concerning the present invention. 4 is a control flow of a winding resistance estimation circuit 44.

Explanation of symbols

  In the drawings, 1 is a washing machine, 15 is a motor, 19 is a rotor, 40 is a motor controller, 42 is a rotational position estimation circuit, 44 is a winding resistance estimation circuit, 71 is an induced voltage estimation circuit, and 82 is a rotational position sensor. (Rotation position detection means) is shown.

Claims (8)

The current flowing in the three-phase permanent magnet motor with a permanent magnet in the rotor is separated into a d-axis current parallel to the magnetic flux created by the permanent magnet and a q-axis current orthogonal thereto, and these current components command the motor rotation speed. Independent control is performed to match each current command value determined to match the value, and the rotational position and speed of the rotor necessary for the control are determined based on motor current, motor voltage, and motor circuit constants. In the motor control device used for the control which is estimated to
Rotation position detection means for detecting that the rotor has reached a specific rotation position and outputting a synchronization pulse;
The resistance value of the armature winding, which is one of the motor circuit constants, so that the estimated rotational position value at the time when the rotational position detection means outputs the synchronization pulse matches the specific rotational position value. And a winding resistance estimating means for estimating a resistance value when the values coincide with each other as a resistance value of the armature winding at that time.   2. The motor control device according to claim 1, wherein the winding resistance estimation unit outputs a synchronization pulse in an operation state in which a d-axis current is zero as a value of the specific rotation position of a rotor. A motor control apparatus using an estimated specific rotational position value which is a value of the estimated rotational position at the time of being performed.   3. The motor control device according to claim 1, wherein the winding resistance estimation unit estimates the resistance value of the armature winding when the estimated rotation speed fluctuation is within a predetermined range. A motor control device.   3. The motor control device according to claim 1, wherein the winding resistance estimation means estimates the resistance value of the armature winding when the variation of the q-axis current is within a predetermined range. A motor control device.   3. The motor control device according to claim 2, wherein the winding resistance estimation means stores the value of the estimated specific rotation position for each q-axis current range, and rotates using the estimated rotation position and rotation speed. An estimated specification that stores the estimated rotational position when the rotational position detection means outputs the synchronization pulse in a state where the speed is controlled, corresponding to the range of the q-axis current to which the q-axis current belongs. The resistance value of the armature winding used for the estimation is adjusted so as to match the value of the rotational position, and the resistance value when matching is estimated as the resistance value of the armature winding at that time Motor control device.   3. The motor control device according to claim 1, wherein a hall sensor is used as the rotational position detecting means.   A washing machine using the motor control device according to any one of claims 1 to 6. The current flowing in the three-phase permanent magnet motor with a permanent magnet in the rotor is separated into a d-axis current parallel to the magnetic flux created by the permanent magnet and a q-axis current orthogonal thereto, and these current components command the motor rotation speed. Independent control is performed to match each current command value determined to match the value, and the rotational position and speed of the rotor necessary for the control are determined based on motor current, motor voltage, and motor circuit constants. A motor control method used for the control by estimating
The rotational position detecting means detects that the rotor has reached the specific rotational position in the operating state where the d-axis current is zero, and stores the estimated rotational position value at that time as the estimated specific rotational position value. Stages,
The motor circuit constant is set so that the estimated rotational position value at the time when the rotational position detecting means detects that the rotor has reached the specific rotational position matches the stored estimated specific rotational position value. Adjusting the resistance value of the armature winding, which is one of the above, and estimating the resistance value when the values match with each other as a resistance value of the armature winding at that time.

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