JP2006203970A - Motor drive device and electric appliance therewith - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To drivingly control a motor by selecting a commanded motor revolution speed and a commanded torque. <P>SOLUTION: A controller selectively executes speed control based on the commanded motor revolution speed and torque control based on the commanded torque. In the case of motor driving at a fixed revolution speed, a first torque current is calculated based on an input commanded motor revolution speed control and the driving control is performed in accordance with the first calculated torque current. In the case of motor driving at a fixed torque, a second torque current is calculated based on an input commanded torque and the driving control is performed in accordance with the second calculated torque current. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a motor driving device for driving and controlling a motor, and further relates to an electric device such as a washing machine and a washing / drying machine using the driving device.

  In order to drive and control a synchronous motor such as a permanent magnet synchronous motor or a synchronous reluctance motor, vector control for detecting a motor current flowing through the motor and controlling the motor based on the detected motor current is generally used. Therefore, the vector control requires a current sensor for detecting a current flowing through the motor in the motor driving device. However, the provision of the current sensor has various problems such as an increase in production cost and an increase in circuit area, and an inability to control due to a component failure.

Therefore, the current sensor is abolished, and instead of the motor current detected by the current sensor, a torque current is calculated from the number of rotations of the motor to perform motor control. For example, Patent Document 1 discloses current sensorless vector control for controlling a motor based on an input command torque. In order to ensure that the motor can be started by the input command torque, drive control is performed so as to increase the voltage applied to the motor until the necessary torque can be output at the time of startup. That is, the motor rotational speed is calculated from the magnetic pole position signal, and when the rotational speed does not increase, the torque current is increased to increase the rotational speed. If the rotational speed is too high, the torque current is reduced to limit the rotational speed.
JP 2003-33068 A

  In the drive control using the command torque (hereinafter referred to as torque control), the motor is driven based on the command torque even after the motor is started. However, in this drive control, it is not possible to arbitrarily set the motor rotation speed and drive-control the motor so that the command motor rotation speed is reached. That is, if a constant command torque is input, the rotational speed is determined by the moment of inertia of the load applied to the motor, and therefore cannot be matched with the command motor rotational speed.

  By the way, in an electric device such as a washing machine driven by a motor, an operation at a constant rotation speed is required like a washing operation or a dehydration operation, and a cloth amount detection operation or a vibration detection operation before these operations is performed. Thus, when detecting the load state of the motor, operation with a constant torque is required.

  However, the above torque control can satisfy only one requirement. Therefore, in an electrical device that requires various operations, a motor drive device that can perform not only torque control but also drive control based on command motor rotation speed (hereinafter referred to as rotation speed control) is desired. In addition, when performing rotation speed control, sufficient output torque is not obtained at the time of starting of a motor, and there exists a possibility that starting may fail.

  In view of the above, an object of the present invention is to provide a motor drive device that can drive and control a motor by rotational speed control and torque control. Another object of the present invention is to provide a motor drive device that can reliably start the motor when the rotational speed control is performed.

  In order to achieve the above object, the present invention includes an inverter circuit that outputs an applied voltage to a motor, and a control device that controls the inverter circuit, and the control device determines the applied voltage based on a command motor rotational speed. A rotation speed control means for calculating, and a torque control means for calculating an applied voltage based on a command torque, wherein the control device is one of the application applied by the rotation speed control means or the torque control means. An applied voltage signal based on a voltage is output to the inverter circuit.

  With the above configuration, the control device can drive the motor by either rotational speed control that controls driving of the motor based on the command motor rotational speed, or torque control that controls driving of the motor based on the command torque.

  Here, the rotation speed control means includes a rotor position detection means for detecting the rotor position of the motor, a rotation angle calculation means for calculating a rotation angle of the motor from the detected rotor position, and a rotation of the motor from the detected rotor position. Motor rotation number calculation means for calculating the number, first torque current calculation means for calculating the first torque current from the calculation motor rotation speed and the target command motor rotation speed, and a command for calculating the command voltage from the first torque current Voltage calculating means; and applied voltage calculating means for calculating an applied voltage to the motor from the command voltage and the rotation angle.

  The torque control means includes a rotor position detection means for detecting the rotor position of the motor, a rotation angle calculation means for calculating the rotation angle of the motor from the detected rotor position, and a second torque current for calculating the second torque current from the command torque. 2 torque current calculating means, command voltage calculating means for calculating a command voltage from the second torque current, and applied voltage calculating means for calculating an applied voltage to the motor from the command voltage and the rotation angle.

  The rotor position detection means detects the switching of the magnetic poles generated with the rotation of the motor, and outputs a magnetic pole position signal to the rotation angle calculation means and the motor rotation number calculation means. The rotation angle calculation means calculates the rotation angle of the motor based on the magnetic pole position signal. Further, the motor rotation number calculation means calculates the motor rotation number based on the magnetic pole position signal.

  The first torque current calculation means calculates a command acceleration from the calculated motor rotation speed and the command motor rotation speed, performs a PI control using the command acceleration as an input, and calculates a first torque current. Specifically, the command acceleration is calculated from the difference between the command motor rotation speed and the calculation motor rotation speed, and the first torque current is calculated according to the command acceleration. As a result, the first torque current can be calculated so that the command motor rotation speed and the calculation motor rotation speed substantially coincide with each other, so that the motor rotation speed can be made to follow the command motor rotation speed. The accuracy of speed control up to can be improved.

  The first torque current calculation means adds the additional torque current to the first torque current at the time of startup. As a result, the torque current at the time of starting the motor is increased, the necessary starting torque can be ensured, and reliable starting can be performed.

  The second torque current calculation means calculates a torque current from the input command torque. The command voltage calculation means calculates the command voltage based on one of the first torque current and the second torque current. The applied voltage calculation means calculates an applied voltage applied to the motor from the command voltage and the rotation angle of the motor, and outputs an applied voltage signal corresponding to the applied voltage to the inverter circuit.

  In addition, the control device includes field current control means for calculating an applied voltage based on a field current corresponding to the detected motor rotation speed in order to reduce the counter electromotive force generated with the rotation of the motor. The field current control means reads the field current from a table storing field current data set for the motor speed and calculates the applied voltage.

  The field current control means performs field weakening current control for reducing the counter electromotive force generated with the rotation of the motor. As a result, even when the motor rotates at a high speed and the back electromotive force increases, the voltage applied to the motor is increased, so that the power shortage due to the back electromotive force can be compensated for and the rotation speed of the motor can be increased. .

  Specifically, the field current control means includes a rotor position detection means for detecting the rotor position of the motor, a motor rotation speed calculation means for calculating the motor rotation speed from the rotor position, and a field current corresponding to the calculated motor rotation speed. Storage means for storing the field current, field current calculation means for calculating the field current, and command voltage calculation means for calculating the applied voltage based on the field current.

  The storage means stores field current data corresponding to the motor speed as a table. The field current calculation means determines the field current with reference to a table when calculating the field current based on the calculation motor rotation speed. Thereby, it is not necessary to sequentially calculate the field current, the amount of calculation for determining the field current can be reduced, and the data processing speed is improved.

  Here, a threshold value of the motor rotation speed when adding the field current is set, and the field current control means applies the applied voltage using the field current read from the table when the motor rotation speed is higher than the threshold value. When the value is equal to or less than the threshold value, the applied voltage is calculated with the field current as a constant value. That is, when the motor rotation speed is equal to or lower than the threshold value, the influence of the counter electromotive force is small, and it is not necessary to add the field current. As a result, it is not necessary to store field current data for the motor rotation speed below the threshold in the table, so that the memory capacity can be reduced.

  As described above, the control device can perform rotation speed control and torque control. However, these drive controls cannot be performed simultaneously. Therefore, the control device includes a selection unit that selects one of the drive controls. Rotational speed control is selected when driving the motor at a constant rotational speed, and torque control is selected when driving the motor at a constant torque. Thus, the two drive controls are not performed simultaneously.

  Examples of electric devices that require two drive controls include a washing machine and a washing / drying machine. In washing operation, rinsing operation, and dehydration operation, motor drive at a constant rotational speed is required. In the cloth detection operation performed before washing operation and vibration detection operation to prevent imbalance during dehydration, a constant torque is required. Motor drive is required. When such an operation command is input, the selection means determines the content of the command and selects one of the drive controls. Therefore, appropriate drive control can be executed according to each operation, and the performance of the washing machine can be improved.

  According to the present invention, the rotational speed control and the torque control can be selectively executed, so that various motor drive controls can be performed as necessary. In addition, when performing the rotation speed control, since the control is performed to increase the voltage applied to the motor at the time of startup, the startup can be performed reliably. By enabling such selective drive control, the applicable range can be expanded to a wide range of uses for electric devices driven by a motor. In particular, by applying it to a washing machine and a washing / drying machine, it is possible to cope with a variety of operations and to improve the performance of electrical equipment.

  FIG. 1 is a block diagram showing a schematic configuration of a motor drive device according to the present invention, FIG. 2 is a diagram showing a data table showing the relationship between motor rotation speed and field current, and FIG. 3 is a case where a threshold value of motor rotation speed is set. It is a figure which shows the data table showing the relationship between the motor rotation speed of this, and a field current.

  As shown in FIG. 1, the motor drive device according to the present invention drives and controls a motor 1, which is a three-phase brushless motor mounted on an electric device, by inverter control by an inverter circuit 2. The inverter circuit 2 is supplied with an applied voltage signal from a microcomputer 3 (hereinafter referred to as a microcomputer 3) as a control device, and outputs an applied voltage to the motor 1 based on this signal.

  The motor 1 has 10 pole pairs. The motor 1 is provided with a rotor position detector 4 that detects the position of the rotor. The rotor position detection unit 4 has a Hall sensor that detects the moment when the N pole and S pole of the permanent magnet are switched. Three hall sensors are arranged at an electrical angle interval of 120 degrees. The rotation of the mechanical angle 36 deg of the motor 1 can be detected by one Hall sensor. Therefore, six combinations are obtained by the three hall sensors, and the rotor position detection unit 4 detects the rotational position of the motor 1 for each mechanical angle of 6 degrees and outputs a magnetic pole position signal to the microcomputer 3.

  The microcomputer 3 selects a rotational speed control for driving and controlling the motor 1 based on the commanded motor rotational speed input by an operation on the electric device and a torque control for controlling the driving of the motor 1 based on the input command torque. During the operation, field current control for driving and controlling the motor 1 based on the field current, that is, field weakening current control is executed. These controls are performed in software according to a program.

  Here, for rotational speed control, rotor position detection means for detecting the rotor position of the motor 1, rotation angle calculation means for calculating the rotation angle of the motor 1 from the detected rotor position, and from the detected rotor position Motor rotation number calculation means for calculating the rotation number of the motor 1, first torque current calculation means for calculating a first torque current from the calculated motor rotation speed and a target command motor rotation speed, and a command voltage from the first torque current And command voltage calculation means for calculating the applied voltage to the motor 1 from the command voltage and the rotation angle.

  For torque control, rotor position detection means for detecting the rotor position of the motor 1, rotation angle calculation means for calculating the rotation angle of the motor 1 from the detected rotor position, and second torque from the command torque to the motor 1 A second torque current calculating means for calculating a current; a command voltage calculating means for calculating a command voltage from the second torque current; and an applied voltage calculating means for calculating an applied voltage to the motor 1 from the command voltage and the rotation angle. .

  The microcomputer 3 includes a rotation angle calculation unit 5 that is a rotation angle calculation unit, a motor rotation number calculation unit 6 that is a motor rotation number calculation unit, a two-phase three-phase voltage conversion unit 7 that is an applied voltage calculation unit, and a two-phase voltage. Calculation unit 8, PI control unit 9 as first torque current calculation unit, field current calculation unit 10 and storage unit 11 as field current control unit, and torque / current conversion as second torque current calculation unit Unit 12, a torque current selection unit 13 that is a selection unit, and an addition unit 14 that is a first torque current calculation unit.

  The motor rotation number calculation unit 6 measures the detection interval of the magnetic pole position signal output from the rotor position detection unit 4 and calculates the rotation number of the motor 1 from the measured time. The detection interval of each Hall sensor is constant, and the rotation angle of the motor 1 at the moment when the magnetic pole switching position is detected can be detected every 6 degrees. Here, in order to obtain an angle other than 6 deg, the motor rotation speed and the rotation angle in the time without the magnetic pole position signal are calculated by measuring the interval of the magnetic pole position signal of the Hall sensor.

  For example, in the same Hall sensor, the number of revolutions can be calculated by measuring the time elapsed for the motor 1 to rotate 36 degrees mechanical angle. If there are three Hall sensors, the motor rotation speed can be calculated from the time required for the motor 1 to rotate by a mechanical angle of 6 degrees.

  In the microcomputer 3 of the present embodiment, the change in the output of the magnetic pole position signal of the Hall sensor is detected at time intervals that are integral multiples of every 2 μsec, which is the minimum time management. The motor rotation speed is calculated using the detected signal detection interval time of the Hall sensor.

  The rotation angle calculation unit 5 calculates the rotation angle of the motor 1 based on the magnetic pole position signal input from the rotor position detection unit 4 and the calculated motor rotation number calculated by the motor rotation number calculation unit 6. Specifically, the magnetic pole switching position detected by any one of the three hall sensors provided in the motor 1 is set as a reference position, and the elapsed time from this reference position to the currently detected magnetic pole switching position is calculated. The rotation angle of the motor 1 is calculated based on the calculated motor rotation speed.

  The adder 14 calculates a command acceleration from the command motor speed input to the microcomputer 3 and the calculated motor speed input from the motor speed calculator 6. The PI control unit 9 performs PI control that inputs commanded acceleration, calculates the first torque current, and outputs the first torque current.

  The torque / current converter 12 calculates the second torque current based on the command torque input to the microcomputer 3 and outputs the second torque current.

  The torque current selector 13 selects and outputs one of the first torque current and the second torque current. That is, when a driving command is issued by an input operation, which drive control is to be performed is determined according to the content of the command. As a result, the input from the PI control unit 9 is allowed to the two-phase voltage calculation unit 8 and the input from the torque / current conversion unit 12 is prohibited or, conversely, from the PI control unit 9 Input is prohibited and input from the torque / current converter 12 is allowed.

  The field current calculation unit 10 determines a field current corresponding to the calculation motor rotation number input from the motor rotation number calculation unit 6 and outputs the field current to the two-phase voltage calculation unit 8. Here, the field current is stored in the storage unit 11, and the field current calculation unit 10 refers to the data in the storage unit 11 to determine the field current.

  As shown in FIG. 2, the storage unit 11 stores field currents as a table. In this table, field current data predetermined for the motor rotation speed is set.

  The two-phase voltage calculation unit 8 calculates a command voltage based on the torque current input through the torque current selection unit 13 and the field current input from the field current calculation unit 10.

  The two-phase three-phase voltage conversion unit 7 converts the command voltage input from the two-phase voltage calculation unit 8 into a three-phase output voltage based on the rotation angle of the motor 1 input from the rotation angle calculation unit 5 and converts it into an inverter. Output to circuit 2.

Next, the rotation speed control will be described. The voltage for driving the motor 1 has the following relational expression. When the voltage of the three-phase motor 1 is converted into a two-phase voltage consisting of dq axes, the d-axis voltage is Vd, and the q-axis voltage is Vq.
Vd = (R × Id) − (ω × Lq × Iq) (1)
Vq = (ω × Ld × Id) + (R × Iq) + (ω × Φ) (2)

  Id is a field current when the current of the motor 1 is converted into a two-phase voltage consisting of a dq axis, Iq is a torque current when the current of the motor 1 is converted into a two-phase voltage consisting of a dq axis, Lq and Ld Is the inductance of the motor 1, R is the winding resistance of the motor 1, ω is the angular velocity of the motor 1, and Φ is the number of flux linkages by the permanent magnet of the motor 1.

  Here, in the equations (1) and (2), the motor constants such as Lq, Ld, R, and Φ are eigenvalues of the motor 1 itself and cannot be changed. The angular velocity ω uses the calculated motor rotation speed calculated based on the magnetic pole position signal from the Hall sensor. However, the calculation motor rotation speed cannot be set arbitrarily because it is the result of rotating the motor 1 by applying a voltage. Therefore, the d-axis voltage Vd and the q-axis voltage Vq, which are command voltages, are controlled by the field current command Id and the torque current Iq.

The relationship between the output torque T of the motor 1 and the motor current is
T = P × {(Φ × Iq) + (Ld−Lq) × Id × Iq} (3)
It becomes. P is the number of pole pairs.

Here, when the motor 1 is started, the field current becomes Id = 0, so if this value is substituted into the equation (3),
T = P × Φ × Iq (4)
It becomes. That is, when starting the motor 1, the output torque T of the motor 1 can be determined only by the torque current Iq. The relationship between the output torque T and the motor rotation speed r is
T−Tr = J × (dr / dt) (5)
It becomes. Note that Tr represents load torque, J represents moment of inertia, and dr / dt represents acceleration of the motor 1.

Therefore, the torque current Iq is calculated from the equations (4) and (5):
Iq = {J × (dr / dt) + Tr} / (P × Φ) (6)
It becomes. Here, in the equation (6), the motor constant, the load torque Tr, and the moment of inertia J are caused by the structure of the motor 1 and cannot be arbitrarily set. That is, the torque current Iq is controlled by the acceleration dr / dt of the motor 1.

Therefore, the acceleration for obtaining the torque current Iq is set as a command acceleration Δr. This command acceleration Δr is a differential value obtained by dividing the difference between the command motor rotation speed r * and the calculation motor rotation speed r by time (speed calculation time t).
Δr = (r * −r) / t (7)
It becomes. Therefore, the PI control using the command acceleration Δr obtained from the equation (7) as an input performs an operation according to the equation (8).
Iq = (Kp × Δr) + (Ki × ∫Δrdt) (8)

  Kp is a P gain and Ki is an I gain. At this time, the PI control unit 9 calculates the torque current Iq so as to suppress the fluctuation range of the motor rotation number, and outputs the result to the two-phase voltage calculation unit 8. Thereby, the rotation speed control of the motor 1 can be performed based on the command motor rotation speed r *, and the rotation speed of the motor 1 can be matched with the command motor rotation speed.

  By the way, when starting the motor 1 by rotation speed control, the big output torque T is required. However, at the time of start-up, since the command motor speed r * is low, it is not possible to generate a torque current Iq that generates a large output torque T. In order to generate a large output torque T, it takes time to make a difference between the arithmetic motor rotational speed r and the command motor rotational speed r *.

Therefore, the PI control unit 9 adds an initial value Iqo (hereinafter referred to as an additional torque current Iqo) to the torque current Iq and outputs the torque current Iq as shown in the equation (9).
Iq = (Kp × Δr) + (Ki × ∫Δrdt) + Iqo (9)

  Thereby, at the time of start-up, the torque current Iq increases, the output torque T increases, and the output torque T that can be started can be generated. Therefore, the motor 1 can be reliably started and the rise time of the motor 1 can be shortened.

  Then, after the motor 1 is started, the component of the (Ki × ∫Δrdt) term, which is the I component of PI control, increases with time, and the component of the additional torque current Iqo is canceled by this I component. Therefore, this additional torque current Iqo does not affect the rotation speed control after startup.

Next, in the case of drive control by torque control, when a command torque is input to the microcomputer 3, the torque / current converter 12 calculates a second torque current Iq based on the command torque T *. At this time, Equation (4) is used.
T * = P × Φ × Iq (10)

  The second torque current Iq is calculated from the equation (10) and output to the two-phase voltage calculation unit 8.

  Torque current Iq is determined according to commanded motor rotational speed r * or commanded torque T * input as described above. By the way, the rotation speed control and the torque control cannot be performed simultaneously. Therefore, as shown in FIG. 4, the microcomputer 3 determines which drive control is executed (S1).

  When the command motor rotation speed is input, the adder 14 calculates the command acceleration Δr from the command motor rotation speed r * and the calculation motor rotation speed r based on the equation (7) and inputs the command acceleration Δr to the PI control section 9. (S2). The PI controller 9 calculates the first torque current Iq from the equation (8) based on the command acceleration Δr, and outputs it to the two-phase voltage calculator 8 (S3). At this time, if a large torque is required to start the motor 1, a certain additional torque current Iqo is added.

  In addition, the field current calculation unit 10 determines a field current Id corresponding to the calculation motor rotation number r from the motor rotation number calculation unit 6. At this time, the field current data corresponding to the arithmetic motor rotation speed r is read from the data table of the storage unit 11 and is set as the field current Id (S6).

  By the way, when the motor 1 rotates at a low speed, the back electromotive force generated along with the rotation is small, so the field current to be added by the field weakening control is set to Id = 0 (S7). Further, since the back electromotive force is large when the motor 1 rotates at high speed, the back electromotive force is decreased by applying a value in the direction of weakening the field to the field current Id. As described above, the field current calculation unit 10 determines the field current Id by referring to the field current data in the data table based on the calculation motor rotational speed r.

  Here, as shown in FIG. 2, the table has a rotation region in which the operation motor rotation speed r is low and the field current Id is not required. That is, an area where the field current is Id = 0 is included in the table. Therefore, a threshold is set for the arithmetic motor rotational speed r when the field current Id is added. The field current calculation unit 10 reads the field current data from the table when the calculation motor rotational speed r is higher than the threshold value, determines the field current Id, and when it is equal to or less than the threshold value, the field current is constant. A value, for example, Id = 0 is applied. Therefore, as shown in FIG. 3, the table stores only field current data when the threshold value is 400 rpm, which is higher than the threshold value. As a result, the storage amount in the storage unit 11 made of a nonvolatile memory can be reduced.

  When such a table is used, the field current calculation unit 10 compares the calculated motor rotation speed r with a threshold value (S5), and if it is equal to or less than the threshold value, the field current is calculated without referring to the table. Set to 0 (S7). Therefore, the load on the microcomputer 3 for determining the field current Id can be reduced, and the processing time is shortened.

  As described above, when the field current Id is determined, it is input to the two-phase voltage calculation unit 8. In the two-phase voltage calculation unit 8, the d-axis voltage Vd and the q-axis voltage Vq are calculated based on the first torque current Iq and the field current Id, and are output to the two-phase three-phase voltage conversion unit 7. (S8).

  The two-phase three-phase voltage converter 7 converts the d-axis voltage Vd and the q-axis voltage Vq into three-phase voltages Vu, Vv, and Vw based on the rotation angle (S9). The three-phase voltages Vu, Vv, and Vw are output to the inverter circuit 2. The inverter circuit 2 generates three-phase voltage signals Vu *, Vv *, Vw * based on the three-phase voltages Vu, Vv, Vw (S10), and outputs the applied voltage generated based on these signals to the motor 1. To do.

  When the command torque T * is input, the torque / current conversion unit 12 calculates the second torque current Iq based on the command torque T * and outputs it to the two-phase voltage calculation unit 8 (S4). At this time, if a large torque is required to start rotation of the motor 1, the additional torque current Iqo is added. Thereafter, similarly, field weakening current control is performed to drive and control the motor 1.

  Next, the motor drive device of this embodiment is applied to a washing machine. The washing machine is a direct drive system in which the motor 1 is directly attached to the washing tub, and the rotation speed of the motor 1 is directly the rotation speed of the washing tub. The washing machine has a washing operation and a rinsing operation in which the washing tub is rotated at a low speed to wash the laundry, a dehydration operation in which the washing tub is rotated at a high speed to perform dehydration, and the laundry cloth in the washing tub. The cloth amount detection operation for detecting the amount and the vibration detection operation for detecting the vibration of the washing machine itself are performed.

  Washing and rinsing require that dirt be removed well. For this purpose, it is important that the washing tub rotates at the set number of rotations, and a low-speed and high-torque rotation operation is required. In the dehydration operation, it is required to reduce moisture by centrifugation in order to dry the laundry quickly. Therefore, high speed rotation of the washing tub is required. That is, it is suitable to perform the rotational speed control in the washing operation and the dehydrating operation.

  In the cloth amount detection operation and the vibration detection operation, it is necessary to rotate the washing tub with a constant torque and know the change in the number of rotations of the washing tub. Therefore, it is suitable to perform torque control in the cloth amount detection operation and the vibration detection operation.

  On the operation panel of the washing machine, a washing switch, a rinsing switch, a dehydration switch, a course switch, a water amount switch, and the like are provided. By operating each switch, the main microcomputer of the washing machine issues a command to the microcomputer 3 of the motor driving device, and each operation is performed. A series of operations of washing, rinsing and dehydration is automatically performed by operating the course switch. By operating the water amount switch, the cloth amount of the laundry is detected, the water supply amount is determined according to the cloth amount, and water supply is performed.

  When the washing machine is operated, the cloth amount detection operation is performed before the washing operation. When the main microcomputer receives an input from the washing switch, the microcomputer 3 starts torque control so as to rotate the motor 1 with a constant torque according to a command from the main microcomputer. The command torque input from the main microcomputer at this time is set in advance, and the microcomputer 3 drives the motor 1 based on the command torque. And the amount of cloth is detected from the number of rotations of a washing tub. Subsequently, water supply according to the amount of cloth is performed, and the washing operation is started.

  The main microcomputer outputs the command motor rotation speed to the microcomputer 3, and the microcomputer 3 performs rotation speed control based on the command motor rotation speed. The command motor rotation speed at this time is preset according to the amount of cloth. When washing operation is performed manually, the strength of washing operation can be selected such as standard, software, and blanket. In this case, the command motor rotational speed set according to the selected strength is input to the microcomputer 3.

  When starting the washing operation and starting the motor 1, the addition torque current is added in the same manner as described above. Then, when the operation is continued after reaching the command motor speed, the motor 1 rotates at a low speed, and therefore the command motor speed is lower than the threshold value for applying the field current. Therefore, the field current is not added to the torque current. The rinsing operation is also driven and controlled in the same manner as the washing operation.

  Next, when performing the dehydration operation, the vibration detection operation is performed before the operation is started. In this operation, torque control is performed. When the imbalance of the washing tub due to the deviation of the laundry is detected by the vibration detection operation, the dehydration operation is started after the deviation is eliminated by water injection.

  In the dehydration operation, a command motor rotational speed set in advance from the main microcomputer is input to the microcomputer 3, and the microcomputer 3 drives and controls the motor 1 based on the command motor rotational speed. Since the dehydration operation is performed at high speed, the microcomputer 3 performs field weakening current control.

  Thereby, the washing machine can rotate a washing tub with the rotation speed which the user intended, without using an electric current sensor. Moreover, since the rotation speed of the motor 1 is controlled by the command torque, a change in the rotation speed can be easily detected, the accuracy of the cloth amount detection can be improved, and the detergent amount can be accurately determined. As a result, a washing machine with good washing performance can be provided.

  Moreover, since the rotation of the motor 1 is smoothly performed by torque control, the vibration of the washing machine body is reduced. As a result, the body can be prevented from overturning and noise can be reduced. In addition, by reducing vibration, the number of times the dehydrating operation is interrupted to avoid danger is reduced, reducing time, saving electricity costs, and the difference between the predicted end time of washing operation and the actual operation time at the start of washing. Less and more accurate end notifications to users.

  In addition, this invention is not limited to the said embodiment, Of course, many corrections and changes can be added to the said embodiment within the scope of the present invention.

  For example, at the time of starting the motor, drive control is performed based on the command torque, and thereafter, the control is switched to rotation speed control based on the command motor rotation speed. This makes it possible to smoothly perform operations from startup to high-speed rotation. Therefore, the present invention can be applied to motor-driven electric devices such as electric vehicles and hybrid vehicles.

The block diagram which shows schematic structure of the motor drive device which concerns on this invention The figure which shows the data table showing the relationship between motor rotation speed and field current The figure which shows the data table showing the relationship between motor rotation speed and field current at the time of setting the threshold value of motor rotation speed Flowchart for controlling motor drive by command motor speed or command torque

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Synchronous motor 2 Inverter circuit 3 Microcomputer 4 Rotor position detection part 5 Rotation angle calculation part 6 Motor rotation speed calculation part 7 Two-phase three-phase voltage conversion part 8 Two-phase voltage calculation part 9 PI control part 10 Field current calculation part 11 Memory | storage Unit 12 torque / current conversion unit 13 torque current selection unit 14 addition unit

Claims (10)

An inverter circuit that outputs an applied voltage to a motor; and a control device that controls the inverter circuit, the control device based on a command torque and a rotation speed control unit that calculates the applied voltage based on the command motor rotation speed. Torque control means for calculating the applied voltage, and the control device provides the inverter circuit with an applied voltage signal corresponding to one of the applied voltages calculated by the rotation speed control means or the torque control means. A motor driving device characterized by outputting. The control device includes a selection unit that selects one of the rotation speed control unit and the torque control unit, and the selection unit selects the rotation speed control unit when rotating the motor at the command motor rotation speed, The motor driving apparatus according to claim 1, wherein when the motor is rotated with a command torque, the torque control unit is selected. The rotation speed control means includes a rotor position detection means for detecting the rotor position of the motor, a motor rotation speed calculation means for calculating the rotation speed of the motor from the detected rotor position, a calculation motor rotation speed and a target command motor rotation. First torque current calculation means for calculating the first torque current from the number, and command voltage calculation means for calculating the applied voltage based on the first torque current, wherein the first torque current calculation means The motor driving apparatus according to claim 1, wherein a command acceleration is calculated from a motor rotation speed and the command motor rotation speed, and the first torque current is calculated based on the command acceleration. The rotation speed control means includes a rotor position detection means for detecting the rotor position of the motor, a motor rotation speed calculation means for calculating the rotation speed of the motor from the detected rotor position, a calculation motor rotation speed and a target command motor rotation. First torque current calculation means for calculating the first torque current from the number, and command voltage calculation means for calculating the applied voltage based on the first torque current, the first torque current calculation means The motor driving apparatus according to claim 1, wherein an additional torque current is added to the first torque current. The first torque current calculation means calculates a command acceleration from the calculated motor rotation speed and the command motor rotation speed, performs PI control using the command acceleration as an input, and calculates the first torque current. 4. The motor drive device according to 4. The control device includes field current control means for calculating an applied voltage based on a field current corresponding to the detected motor rotation number in order to reduce a counter electromotive force generated with the rotation of the motor, 3. The field current control means reads the field current from a table storing field current data set for the motor rotation number, and calculates an applied voltage. Motor drive device. A threshold value of the motor rotation speed when adding the field current is set, and the field current control means calculates the applied voltage using the field current read from the table when the motor rotation speed is higher than the threshold value. The motor drive device according to claim 6, wherein when the value is equal to or less than the threshold value, the applied voltage is calculated with the field current as a constant value. An electric apparatus comprising the motor drive device according to claim 1. The electric device according to claim 8, wherein the electric device is a washing machine or a washing / drying machine. In the washing operation or the dehydration operation, the motor is driven and controlled based on the rotational speed control means, and in the case of the cloth amount detection operation or the vibration detection operation, the motor is driven and controlled based on the torque control means. The electric device according to claim 9.

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