Motor control device, washing machine, and position sensorless motor control method

Abstract

To provide a motor control device, washing machine, and position sensorless motor control method capable of determining clutch engagement even with sensorless motor control.SOLUTION: A motor control device 100 includes an induced voltage detection unit 44 that detects the induced voltage of a motor 20 when the output of a power conversion device 131 is stopped, a rotation speed detection unit 45 that detects the rotation speed of the motor 20 on the basis of the detected induced voltage of each phase, and an engagement determination unit 46 that determines whether the engagement operation, which switches the rotation force transmission destination of the motor 20 on the basis of the detected induced voltage of each phase.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a motor control device, a washing machine, and a position sensorless motor control method. [Background technology]

[0002] Patent Document 1 describes a washing machine equipped with a drive motor and a speed reduction mechanism that reduces the speed of the drive motor. The drive mechanism drives an agitator with the drive motor via a speed reduction mechanism, and the drive shaft of the drive motor is configured on the same axis as the speed reduction mechanism. The speed reduction mechanism is equipped with an electrically operated clutch mechanism and a planetary gear reduction mechanism inside, which switch between washing and spin-drying operations. The document describes that the electrically operated clutch mechanism allows the agitator to rotate left and right while the washing and spin-drying tub is stationary (agitation mode), or to rotate the washing and spin-drying tub and agitator together in the same direction (spin-drying mode).

[0003] Furthermore, a washing machine equipped with a conventional clutch mechanism uses a position sensor (Hall element) to achieve the following functions. This performs a mating check for the clutch mechanism (the part that switches the motor that drives the agitator blades and washing tub and the part that transfers the motor's torque). If the number of signals from the Hall element exceeds a predetermined threshold at a specific timing, it determines that the lower mating operation (the mating operation that transfers the motor's torque to the washing tub) is normal.

[0004] Washing machines equipped with a clutch mechanism detect the magnetic pole position of the main motor. If no signal is obtained from the Hall element within a certain period of time (i.e., the magnetic pole position of the motor does not rotate), the washing machine is determined to be in a stopped state.

[0005] To further reduce the size of devices that use motors, position sensorless technology is being applied, which estimates the magnetic pole position of a motor without using a sensor. A known position sensorless technology is a conventional technology that estimates the magnetic pole position based on a calculated value of the axis error (Δθc) between the real axis (dq axis) and the control axis (dc-qc axis) of the motor (see, for example, Patent Document 2 and Patent Document 3).

[0006] Patent Document 2 describes a motor control device that has a synchronous operation mode that does not use information related to the rotational angle position and a position sensorless operation mode that drives using information related to the rotational angle position, and switches between the operation modes during driving.

[0007] Patent Document 3 describes a motor control device that uses the timing when the motor torque changes or stabilizes during position feedback operation mode as a trigger, and sets an electrical quantity related to at least one of the calculation means and the current controller based on a value proportional to the torque after the change in accordance with the trigger. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-217178 [Patent Document 2] Japanese Patent Application Laid-Open No. 2013-46424 [Patent Document 3] Japanese Patent Application Laid-Open No. 2012-65373 Summary of the Invention [Problem to be solved by the invention]

[0009] In the motor control devices described in Patent Documents 2 and 3, the following problems arise due to the position sensorless control of the main motor (elimination of Hall elements). (1) It becomes impossible to determine whether the clutch mechanism is engaged (see below). (2) The motor status (rotating or stopped) cannot be determined (see below).

[0010] The present invention has been made in consideration of the above circumstances, and aims to provide a motor control device, a washing machine, and a position sensorless motor control method that can determine whether a clutch mechanism is engaged even when the motor is controlled without a position sensor. [Means for solving the problem]

[0011] In order to solve the above problems, the motor control device of the present invention is a motor control device equipped with a power conversion device that supplies AC power to a motor, and is characterized by comprising an induced voltage detection unit that detects the induced voltage of the motor when the output of the power conversion device is stopped, a rotation speed detection unit that detects the rotation speed of the motor based on the detected induced voltage of each phase, and a fitting determination unit that determines whether the fitting operation that switches the destination of transmission of rotational force of the motor is normal based on the detected induced voltage of each phase. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a motor control device, a washing machine, and a position sensorless motor control method that are capable of determining whether a clutch mechanism is engaged even when the motor is controlled without a position sensor. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a functional block diagram showing the configuration of a motor control device according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a block diagram of a computer of the motor control device according to the first embodiment of the present invention. [Figure 3] 1 is a schematic cross-sectional view of a vertical washing machine according to a first embodiment of the present invention. [Figure 4] 1 is a diagram schematically illustrating the structure of a motor of a motor control device according to a first embodiment of the present invention. [Figure 5] 2 is a diagram showing the relationship between a three-phase AC axis and a two-phase AC axis of the motor control device according to the first embodiment of the present invention. FIG. [Figure 6] 3 is a diagram showing the relationship between the rotor position θd and the phase of each winding of the stator in the motor control device of the first embodiment of the present invention. FIG. [Figure 7] FIG. 2 is a diagram showing a start-up sequence when starting up a motor of the motor control device of the first embodiment of the present invention. [Figure 8A] 3 is a diagram showing phase current values ​​from motor startup to motor rotation of the motor control device of the first embodiment of the present invention. FIG. [Figure 8B]FIG. 3 is a diagram showing phase current values ​​in a motor positioning mode of the motor control device according to the first embodiment of the present invention. [Figure 8C] 3 is a diagram showing phase current values ​​during motor rotation of the motor control device according to the first embodiment of the present invention. FIG. [Figure 9] 2 is a diagram illustrating an example of the configuration of a current detection unit of the motor control device according to the first embodiment of the present invention. FIG. [Figure 10] 2 is a diagram illustrating an example of the configuration of a current control unit of the motor control device according to the first embodiment of the present invention. FIG. [Figure 11] 1 is a diagram illustrating an overview of an induced voltage detection unit and a rotation speed detection unit that uses an induced voltage of a motor control device according to a first embodiment of the present invention. [Figure 12] 3 is a circuit diagram showing a detailed configuration of an induced voltage detector that uses an induced voltage and a rotation speed detector of the motor control device according to the first embodiment of the present invention. FIG. [Figure 13] 3 is a diagram showing a detailed configuration of an induced voltage detection unit that uses an induced voltage and a rotation speed detection unit of the motor control device according to the first embodiment of the present invention. FIG. [Figure 14] 2 is a diagram illustrating an example of a circuit configuration of an AD converter of the motor control device according to the first embodiment of the present invention. FIG. [Figure 15] 4 is a diagram showing the relationship between the induced voltage of each phase and the output of the phase detector when the motor rotation direction of the motor control device of the first embodiment of the present invention is CCW. FIG. [Figure 16] 4 is a flowchart of a fitting abnormality determination process of the motor control device according to the first embodiment of the present invention. [Figure 17A] 3 is a diagram schematically showing three-phase current values ​​in a normal state while the motor is rotating in the motor control device of the first embodiment of the present invention. FIG. [Figure 17B] 3A and 3B are diagrams showing three-phase current values ​​during normal operation and during disconnection while the motor is rotating in the motor control device of the first embodiment of the present invention. [Figure 18] 1 is a diagram illustrating an example of the configuration of an ACR of a motor control device according to a first embodiment of the present invention. [Figure 19] FIG. 3 is a diagram showing a motor current of a DC motor control unit of the motor control device according to the first embodiment of the present invention. [Figure 20] FIG. 4 is a functional block diagram showing the configuration of a motor control device according to a second embodiment of the present invention. [Figure 21] FIG. 10 is an explanatory diagram of torque generated during positioning of the motor control device according to the second embodiment of the present invention. [Figure 22] FIG. 10 is an explanatory diagram of torque generated during positioning when the phase difference Δθ between the control phase θdc and the actual phase θd of the motor control device according to the second embodiment of the present invention is 180°. [Figure 23] FIG. 10 is an explanatory diagram of torque generated during positioning when the positioning current Idc of the motor control device according to the second embodiment of the present invention is small. [Figure 24] 10 is an explanatory diagram of torque generated during positioning when the positioning current Idc of the motor control device according to the second embodiment of the present invention is large. FIG. [Figure 25] FIG. 10 is an explanatory diagram of torque generated during positioning when the phase difference (axis error) Δθ=−135[deg] between the control phase θdc=45[deg] and the actual phase θd=180[deg] of the motor control device according to the second embodiment of the present invention. [Figure 26] FIG. 10 is an explanatory diagram of torque generated during positioning when the phase difference (axis error) Δθ=−90[deg] between the control phase θdc=45[deg] and the actual phase θd=135[deg] of the motor control device according to the second embodiment of the present invention. [Figure 27] FIG. 10 is an explanatory diagram of torque generated during positioning when the phase difference (axis error) Δθ=0[deg] between the control phase θdc=45[deg] and the actual phase θd=45[deg] of the motor control device of the second embodiment of the present invention. [Figure 28] FIG. 10 is a diagram showing a control sequence for two-stage positioning of a motor control device according to a second embodiment of the present invention. [Figure 29] FIG. 10 is an explanatory diagram of torque generated during positioning when the phase difference (axis error) Δθ=−160[deg] between the control phase θdc=0[deg] and the actual phase θd=160[deg] of the motor control device according to the second embodiment of the present invention. [Figure 30]FIG. 10 is an explanatory diagram of torque generated during positioning when the phase difference (axis error) Δθ=−130[deg] between the control phase θdc=30[deg] and the actual phase θd=160[deg] of the motor control device according to the second embodiment of the present invention. [Figure 31] FIG. 10 is an explanatory diagram of torque generated during positioning at time D when the phase difference (axis error) Δθ=20[deg] between the control phase θdc=90[deg] and the actual phase θd=110[deg] of the motor control device of the second embodiment of the present invention. [Figure 32] FIG. 10 is an explanatory diagram of torque generated during positioning when the phase difference (axis error) Δθ=20[deg] between the control phase θdc=180[deg] and the actual phase θd=160[deg] of the motor control device of the second embodiment of the present invention. [Figure 33] FIG. 10 is an explanatory diagram of torque generated during positioning at time E when the phase difference (axis error) Δθ=20[deg] between the control phase θdc=180[deg] and the actual phase θd=160[deg] of the motor control device of the second embodiment of the present invention. [Figure 34] FIG. 10 is an explanatory diagram of torque generated during positioning when the phase difference (axis error) Δθ=0[deg] between the control phase θdc=180[deg] and the actual phase θd=180[deg] of the motor control device of the second embodiment of the present invention. [Figure 35] 10 is a flowchart showing control of two-stage positioning in which the positioning setting unit of the motor control device of the second embodiment of the present invention "advances the control phase θdc during positioning." [Figure 36] FIG. 10 is a functional block diagram showing the configuration of a motor control device according to a third embodiment of the present invention. [Figure 37] 10A to 10C are diagrams illustrating a removal process of the motor control device according to the third embodiment of the present invention. [Figure 38] FIG. 37 is a diagram showing the rotation speeds in the dehydration process and the loosening process in the case where the Hall sensor is used, as shown in the left diagram of FIG. [Figure 39] This is a diagram showing the rotation speeds of the spin-drying process, peeling process, and loosening process in the "without Hall sensor" diagram on the right of Figure 37. [Figure 40] FIG. 40 is a diagram illustrating the details of the peeling step in FIG. 39. [Figure 41]10 is a flowchart showing details of a peeling process of a motor control device according to a third embodiment of the present invention. [Figure 42] FIG. 10 is a functional block diagram showing the configuration of a motor control device according to a fourth embodiment of the present invention. [Figure 43] FIG. 10 is a diagram showing changes in the current command value, three-phase current, and rotation speed when decelerating from a constant speed and then operating at a constant speed again in a comparative example ("no current increase") of the motor control device of the fourth embodiment of the present invention. [Figure 44] FIG. 11 is a diagram showing changes in the current command value, three-phase current, and rotation speed when the motor control device of the fourth embodiment of the present invention decelerates from a constant speed and then resumes constant speed operation. [Figure 45] 10 is a flowchart showing Id setting control of a current boost setting unit of a motor control device according to a fourth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. (First embodiment) A motor control device according to a first embodiment of the present invention will be described below. This embodiment is an example in which the motor control device is applied to a vertical washing machine. In the following description, the rotational speed of the motor is referred to as the number of rotations of the motor.

[0015] FIG. 1 is a schematic configuration diagram of a motor control device according to a first embodiment of the present invention. 1, motor control device 100 controls motor 20 and includes control unit 40, DC voltage source 120, power conversion unit 130, current detection unit 50, current detection unit 41, current control unit 42, PWM signal generation unit 43, induced voltage detection unit 44, rotation speed detection unit 45, and fit determination unit 46. Details of each unit will be described later.

[0016] The motor 20 is, for example, a permanent magnet synchronous motor having a permanent magnet in the rotor, but is not limited to this type of motor 20. In addition, although not shown, a mechanism for mechanically or magnetically transmitting mechanical output is connected to the motor 20.

[0017] <DC voltage source 120> A DC voltage source 120 is connected to the power conversion unit 130 via a shunt resistor 135. The DC voltage source 120 outputs a DC voltage Edc. The DC voltage source 120 may be an AC / DC converter that converts a commercial AC voltage into a DC voltage, a DC / DC converter that controls a DC voltage to a different DC voltage, or a battery. The current detection unit 50 detects the input current supplied to the power conversion unit 130 from the DC voltage source 120 based on the voltage drop across the shunt resistor 135, and outputs the result as an input current detection value Ish. The shunt resistor 135 also has a function of protecting the power conversion unit 130 by preventing excessive current from flowing through the power conversion unit 130.

[0018] <Power conversion unit 130> The power conversion unit 130 is, for example, an inverter circuit, and in the illustrated example, includes a gate driver 123 and a power conversion device 131. The power conversion device 131 includes three switching elements Q1, Q3, and Q5 (first switching elements) in an upper arm, three switching elements Q2, Q4, and Q6 (second switching elements) in a lower arm, and diodes (no reference numerals) connected in anti-parallel to these elements. This allows the power conversion device 131 to form a three-phase bridge circuit.

[0019] In the illustrated example, switching elements Q1 to Q6 are IGBTs (Insulated Gate Bipolar Transistors), but MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors) may be used instead. Gate driver 123 controls the on / off states of switching elements Q1 to Q6 to PWM (Pulse Width Modulation) the output voltage of DC voltage source 120, and applies an AC voltage to motor 20.

[0020] It is assumed that the switching operations of the switching elements Q1 to Q6 are ideally switched without delay. In other words, the voltage output from the power conversion device 131 is a pulsed voltage. Using the well-known concept of pulse width modulation (PWM), the pulsed voltage can be regarded as an AC voltage. In pulse width modulation, it is common to set the cycle at which the switching elements Q1 to Q6 are turned on and off, i.e., the switching frequency, sufficiently high relative to the frequency of the equivalent AC voltage (here, this corresponds to the rotation frequency of a single-phase motor).

[0021] The voltage of each phase of the power converter 131 is controlled by the switching state of the upper and lower arms in the power converter 131. In the power converter 131, switching is performed at a frequency that is sufficiently higher than the frequency of the AC voltage appearing at the motor 20, so the output voltage of each phase of the power converter 131 can be freely adjusted by changing the switching ratio (switching duty) of the upper and lower arms. In other words, the power converter 131 can apply a three-phase AC voltage of any frequency to the motor 20, thereby realizing variable speed drive and torque control of the motor 20.

[0022] In the power conversion unit 130 shown in FIG. 1, the power conversion device 131 and the gate driver 123 are configured independently, but an IPM (Intelligent Power Module) that combines both in a single package may also be applied as the power conversion unit 130.

[0023] <Control unit 40> The control unit 40 controls the switching states of the switching elements Q1 to Q6 in the power conversion device 131 based on the input current detection value Ish obtained by the current detection unit 50. This allows the control unit 40 to control the rotation speed or torque of the motor 20 to a desired value. To this end, the control unit 40 includes a current detection unit 41, a current control unit 42, a PWM signal generation unit 43, an induced voltage detection unit 44, a rotation speed detection unit 45, and a fit determination unit 46. Details of each of these components of the control unit 40 will be described later.

[0024] 2 is a block diagram of the computer 980. The control unit 40 shown in FIG. 1 includes one or more computers 980 shown in FIG. 2, the computer 980 includes a CPU (Central Processing Unit) 981, a storage unit 982, a communication I / F (Interface) 983, an input / output I / F 984, and a DSP (Digital Signal Processor) 985. The storage unit 982 includes a RAM 982a and a ROM 982b. The communication I / F 983 is connected to a communication circuit 986. The input / output I / F 984 is connected to an input / output device 987.

[0025] The ROM 982b stores control programs and various data executed by the CPU 981 and DSP 985. The CPU 981 and DSP 985 execute these control programs to realize various functions. The interior of the control unit 40 shown in FIG. 1 is primarily a block diagram of functions realized by the control programs and the like.

[0026] <Vertical washing machine 200> FIG. 3 is a schematic cross-sectional view of a vertical washing machine 200 (washing machine) according to the first embodiment. The following description will be given taking as an example a vertical washing machine 200 that can wash, rinse, and spin-dry. The vertical washing machine 200 of the present invention can also be applied to a vertical washing machine that can perform a drying process. 3, the vertical washing machine 200 includes a housing 6 and an outer lid 5 (lid) attached to the housing 6. The vertical washing machine 200 also includes a washing / spin-drying tub 7, a washing tub 3, a motor 20, a clutch mechanism 9, and a motor control device 100 (FIG. 1) inside the housing 6 and the outer lid 5. A door lock unit 11 locks the outer lid 5 in the closed state. Washing / spin-drying tub 7 has a cylindrical shape with a bottom that accommodates laundry (clothes) to be washed and spin-dried.

[0027] The clutch mechanism 9 is a part that switches between the motor 20 that drives the agitating blade 4 and the washing and spin-drying tub 7 and the destination of the rotational force of the motor 20 . Clutch mechanism 9 switches the destination of the rotational force of motor 20 by an engaging operation that allows the rotational force of motor 20 to be transmitted to washing and spin-drying tub 7 . The clutch mechanism 9 rotates the agitator blade 4 while the washing and spin-drying tub 7 is stationary, or switches the destination of the rotational force of the motor 20 by engaging operation, causing the washing and spin-drying tub 7 and the agitator blade 4 to rotate integrally in the same direction.

[0028] Motor 20 is provided in housing 6 and selectively drives agitator blade 4 and washing / spin-drying tub 7 to rotate via clutch mechanism 9. Motor 20 is, for example, a DC brushless motor driven by direct current. The DC brushless motor is controlled by vector control using control unit 40 (FIG. 1).

[0029] In the washing process, laundry is placed in washing / spin-drying tub 7, wash water is stored in washing tub 3 from water supply device 8, and only agitator 4 connected to motor 20 is rotated to wash the laundry. In the spin-drying process, clutch mechanism 9 connected to motor 20 is switched (lower engaged), and both washing / spin-drying tub 7 and agitator 4 are rotated, spinning the laundry by centrifugal force.

[0030] According to this embodiment, the motor 20 that rotates the washing / spin-drying tub 7 or the agitating blade 4 of the vertical washing machine 200 can be driven in a position sensorless manner without using a position sensor.

[0031] <Motor 20> FIG. 4 is a diagram schematically illustrating the structure of the motor 20. As shown in FIG. The motor 20 includes a stator 21 and a rotor 22. The stator 21 has multiple stator poles 28, each with a winding 25 wound around a stator core 26. The rotor 22 includes permanent magnets 27. FIG. 3 shows an example in which the number of magnetic poles (also called the number of slots) of the stator is six, and the number of magnetic poles of the rotor 22 is two. However, the numbers of magnetic poles of the stator 21 and rotor 22 can be freely selected, and the numbers of magnetic poles of the stator and rotor may not be equal. The multiple windings 25 may be connected in parallel or in series. In this specification, the windings 25 of opposing stator poles 28 are connected in series to form one phase, and the motor 20 will be described as having three-phase windings.

[0032] When a current flows through the windings 25, the stator magnetic poles 28 are generated in the same manner as electromagnets. The polarity (north pole, south pole) changes depending on the direction of the current through the windings 25. In this specification, the rotation angle (rotational angle position) of the rotor 22 when a positive direct current flows through the windings 25 and the stator magnetic poles 28 become south poles, attracting the north poles of the permanent magnets 27 of the rotor 22, is defined as zero degrees. Hereinafter, the rotational angle position of the rotor is referred to as the rotor position θd (actual phase). The position of any one of the multiple windings 25 is defined as the reference position. In this specification, the winding 25 on the right side of FIG. 4 (the winding closest to the U-phase) is described as the reference position. In this specification, the counterclockwise rotation of the rotor 22 is defined as forward rotation (CCW).

[0033] <Coordinate axis definition> Here, the definition of the coordinate axes will be explained. FIG. 5 is a diagram showing the relationship between the three-phase AC axis and the two-phase AC axis. Here, the three-phase AC axis has a U-phase axis, a V-phase axis, and a W-phase axis, and is a stationary coordinate system based on each winding 25 of the stator 21. The two-phase AC axis is a stationary coordinate system having an α-axis and a β-axis, and the three-phase AC axis is represented by the two-phase axis. The current values ​​iu, iv, and iw on the three-phase AC axis can be converted into current values ​​iα and iβ on the two-phase AC axis, for example, by the following equation (1). As is clear from the following equation (1), information on the rotor position θd is not required for this conversion. iα=1·iu-(1 / 2)·iv-(1 / 2)·iw iβ=0·iu+(√3 / 2)·iv-(√3 / 2)·iw ...Formula (1)

[0034] <Relationship between the three-phase axes in the fixed coordinate system and the control axes> FIG. 6 is a diagram showing the relationship between the rotor position θd and the phase of each winding 25 of the stator 21. The three-phase windings 25, U-phase, V-phase, and W-phase, are arranged with a difference of 120 degrees in electrical angle. Here, the direction of the main magnetic flux of the permanent magnet 27 provided in the rotor 22 is defined as the d-axis, and the axis that is 90 degrees electrically ahead of the d-axis in the direction of rotation (90 degrees electrical angle) is defined as the q-axis, defining a dq-axis consisting of the d-axis and q-axis. This dq-axis is a rotating coordinate system. The d-axis can also be defined as "the rotation angle position at which the magnetic flux of the permanent magnet 27 that links with the reference winding 25 is at its maximum." The dq-axis is called the real axis, and the dc-qc-axis is called the control axis. θd is called the real phase, and θdc is called the control phase.

[0035] The rotational angle position (magnetic pole position) of the dc axis is defined as θdc, with the U phase as the reference. The dc axis rotates in the direction of the arrow in the diagram, and the magnetic pole position θdc can be obtained by integrating the rotation frequency (the inverter frequency command value ω1, which will be explained later).

[0036] In this example, a permanent magnet motor having a permanent magnet in the rotor is used as the motor 20. Therefore, the position of the control shaft and the position of the rotor are basically synchronized. Rotor rotation angle position information is obtained by position sensorless control, which estimates the position based on information such as the current flowing through the motor 20 and the voltage applied to the motor.

[0037] <Sensorless control> Position sensorless control converts the reproduced motor three-phase current into the control axis (dc-qc axis) of the rotating coordinate system, calculates the axis error between the motor rotor axis (dq axis) and the control axis from the vector voltage command value and the detected current value, and adjusts the motor current command and motor rotation speed (rotational speed) using a PLL (Phase Locked Loop) controller and speed controller (ASR).

[0038] <Basic operation when starting the motor 20> The basic operation when starting the motor 20 will now be described. Fig. 7 is a diagram showing a start-up sequence when starting the motor 20. Fig. 7 shows the transition of the operation mode when the load is heavy when starting the motor 20. There are three operation modes: a "positioning mode" in which a DC current is passed through the motor winding of any phase to fix the stator of the motor 20 at a certain position; a "synchronous operation mode" in which the voltage applied to the motor 20 is determined based on the d-axis current command value Id*, the q-axis current command value Iq*, and the frequency command value ω*; and a "position sensorless mode" in which the inverter frequency command value ω1 is adjusted so that the axis error Δθc becomes zero.

[0039] These operation modes are switched to another operation mode by changing one or more of the d-axis current command value (Id*), the q-axis current command value (Iq*), and the inverter frequency command value ω1, or by switching a control changeover switch (not shown) provided in the control unit 40 (FIG. 1).

[0040] Positioning mode In the positioning mode, as shown in FIG. 7, the rotor is fixed at a predetermined fixed position by linearly increasing only the dc-axis current command from 0 and gradually increasing the DC current flowing through the motor windings. In the positioning mode, the frequency command value ω* becomes the inverter frequency command value ω1 as is. Furthermore, the q-axis current command value Iq*0 at startup becomes the q-axis current command value Iq* as is. In the positioning mode d, the inverter frequency command value ω1 is set to zero because DC current flows through the motor 20. On the other hand, the d-axis current command value Id* increases linearly over time, as shown in FIG. 7. The phase to be positioned may be fixed to a specific phase, or may be different each time the motor is started. For example, if θdc is set to zero, the rotor is positioned to the U phase.

[0041] Synchronous operation mode After the positioning mode is completed, the mode transitions to the synchronous operation mode. In the synchronous operation mode, predetermined current command values ​​(Idc*, Iqc*) are given to an ACR (Automatic Current Regulation: Current Controller) (Fig. 18) (a simple configuration is the current control unit 42 in Fig. 10) to control the motor current. At the same time, the motor rotation speed command (ω1*) is gradually increased to accelerate the motor. The control phase (θdc) is calculated from the speed command (ω1*) using an integrator. In the synchronous operation mode, the d-axis current command value Id* is kept constant (this startup method is called d-axis startup) and the inverter frequency command value ω1 is increased. As a result, the motor 20 accelerates in accordance with the inverter frequency command value ω1.

[0042] Position sensorless mode In position sensorless mode, a PLL controller (not shown) and a speed controller (not shown) are used to adjust the qc-axis current command value (Iqc*) and control phase (θdc) so that the axis error (Δθc) calculated from the vector voltage command value and the detected current value becomes zero. In position sensorless mode, the PLL controller operates to adjust the inverter frequency command value ω1 so that the axis error Δθc becomes the axis error command value Δθ* (usually zero). At the same time, the speed controller adjusts the q-axis current command value Iq* so that the difference between the frequency command value ω* given from an external device such as a higher-level controller and the inverter frequency command value ω1 becomes zero.

[0043] As shown in Figure 7, when the load is heavy, the load angle becomes larger. This causes a large current to flow on the q-axis, and motor 20 generates a larger torque. In other words, when the load is heavy, the axis error Δθc in synchronous operation mode becomes a larger positive value. Therefore, when the mode is switched to position sensorless mode and the PLL controller operates, the inverter frequency command value ω1 is further reduced.

[0044] 8A-8C are diagrams showing three-phase current values ​​of motor 20. FIG. 8A shows phase current values ​​from motor startup to motor rotation, FIG. 8B shows phase current values ​​in positioning mode, and FIG. 8C shows phase current values ​​while the motor is rotating. The upper part of FIG. 8B shows the overall three-phase current values, and the lower part of FIG. 8B is an enlarged view at the zoom position. The upper part of FIG. 8C shows the overall three-phase current values, and the lower part of FIG. 8C is an enlarged view at the zoom position.

[0045] <Details of the control unit 40> Each part of the control unit 40 will be described in detail below. FIG. 9 is a diagram showing an example of the configuration of the current detection unit 41. As shown in FIG. The current detection unit 50 includes an amplifier circuit 136 such as an operational amplifier. The amplifier circuit 136 amplifies the terminal voltage of the shunt resistor 135 and outputs the result as an input current detection value Ish. The current detection unit 41 includes a sample-and-hold unit 137 and an ADC (analog-to-digital converter) 138.

[0046] In the sample-and-hold unit 137, a trigger signal that indicates the timing of sample-and-hold may be generated based on the timing when the two-phase short-circuit braking mode MB (not shown), i.e., the timing when the switching element Q1 of the upper arm of the U phase turns on. More specifically, the timing of sample-and-hold may be determined taking into consideration the start-up delay of the ADC 138, the turn-on delay of the switching elements Q1 to Q6, ringing caused by switching, etc. The ADC 138 converts the analog signal output by the sample-and-hold unit 137 into a digital signal and outputs the result as the α-phase current detection value Iα.

[0047] FIG. 10 is a diagram showing an example of the configuration of the current control unit 42. The current control unit 42 includes a subtractor 91, a proportional control unit 96, an integral control unit 97, an adder 90, and a limiting unit 87. The subtractor 91 subtracts the α-phase current detection value Iα from the α-phase current command value Iα*. The proportional control unit 96 multiplies the subtraction result (Iα*-Iα) output by the subtractor 91 by a proportional control gain Kp and outputs the multiplication result. A more detailed configuration of the current control unit 42 will be described later as an ACR (current controller) in FIG. 18.

[0048] The integral control unit 97 integrates the subtraction result, multiplies the integration result by an integral control gain Ki, and outputs the multiplication result. The adder 90 adds the output signals of the proportional control unit 96 and the integral control unit 97, and outputs the addition result. This allows the current control unit 42 to perform proportional-plus-integral control. The α-phase current command value Iα* may be determined according to the specifications of the control unit 40, and can be determined, for example, by the following equation (2) or (3):

[0049] Iα*=(Edc×C1) / R …Equation (2) Iα*=Irated×C2 …Equation (3)

[0050] In equation (2), R is the resistance value of the winding 25 of the motor 20, and Edc0 is the DC voltage source 120 is the nominal value of the DC voltage Edc to be output, and C1 is a predetermined DC voltage ratio constant. In addition, in equation (3), Irated is the rated current value of the motor 20, and C2 is a predetermined rated current ratio constant.

[0051] When formula (2) is used and the DC voltage ratio constant C1 is set to, for example, 0.05, the α-phase current command value Iα* is set so that the U-phase voltage (i.e., the α-phase voltage) is equal to a voltage corresponding to 5% of the DC voltage nominal value Edc0. When formula (3) is used and the rated current ratio constant C2 is set to, for example, 0.1, the α-phase current command value Iα* is set so that a current equivalent to 10% of the rated current flows in the U-phase current (i.e., the α-phase current). The α-phase current command value Iα* may be generated by the current detection unit 41, or may be acquired from a higher-level control system or another control system.

[0052] The limiting unit 87 limits the absolute value of the output signal of the adder 90 so that it falls within a predetermined range, and outputs the limited output signal as the α-phase voltage command value Vα*. The limiting unit 87 is provided to ensure a pulse width that enables current detection. Therefore, if there is no particular need to limit the absolute value of the output signal of the adder 90, the limiting unit 87 may be omitted, and the output signal of the adder 90 may be output as the α-phase voltage command value Vα*.

[0053] The PWM signal generating unit 43 shown in FIG. 1 outputs a drive signal that specifies the on / off state of each of the switching elements Q1 to Q6 based on the α-phase voltage command value Vα*.

[0054] <Configuration Example 1 of Induced Voltage Detector 44 and Rotational Speed ​​Detector 45> FIG. 11 is a diagram showing an outline of the induced voltage detector 44 and the rotation speed detector 45 that uses the induced voltage. The induced voltage detection unit 44 detects the induced voltage generated in the motor 20. For example, the induced voltage detection unit 44 compares the detected induced voltages between two phases using a comparator, and generates a pulse based on the comparison result of the induced voltages between the two phases.

[0055] The induced voltage detector 44 includes a pulse generator that generates a pulse signal based on the detected induced voltage of each phase, and the rotation speed detector 45 detects the rotation speed of the motor 2 based on the pulse signal.

[0056] The induced voltage detection unit 44 includes a pulse generation means for generating a pulse signal based on the detected induced voltage of each phase, and the mating determination unit 46 determines whether the mating operation for switching the destination of the rotational force of the motor 20 is normal when the number of pulse signals is equal to or greater than a predetermined threshold value based on the pulse signals.

[0057] In this embodiment, the induced voltage detection unit 44 generates a pulse signal based on the detected induced voltage of each phase, but the use of a pulse signal is merely an example, as long as it detects the induced voltage generated in the motor 20. For example, the points where the induced voltages of each phase intersect may be counted as the HIGH / LOW switching points.

[0058] Even after the power supply to motor 20 is stopped, washing and spin-drying tub 7 continues to rotate due to the inertial force. As a result, motor 20, which is mechanically connected to washing and spin-drying tub 7, which has a large mass, also continues to rotate due to the inertial force (motor 20 is rotating by inertia when washing and spin-drying tub 7 comes to a coasting stop). In this state, motor 20 acts as a generator and generates an induced voltage in each phase. In other words, when motor 20 comes to a coasting stop, motor 20 generates an induced voltage until it stops rotating. Specifically, with the PWM output to the three-phase inverter stopped, a determination is made using a pulse signal based on the induced voltage, rather than using the current (see FIG. 15 for details, which will be described later). The motor control device 100 (FIG. 1) includes a PWM signal generating unit 43, an induced voltage detecting unit 44, a rotation speed detecting unit 45, and a fitting determining unit .

[0059] The PWM signal generating unit 43 generates a PWM signal by comparing the AC voltage command with the PWM carrier wave, and generates a control signal for controlling the power conversion device 131 based on the PWM signal.

[0060] Induced voltage detector 44 detects the induced voltage during inertial rotation of motor 20 when PWM signal generator 43 stops outputting the PWM signal and washing / spin-drying tub 7 comes to an inertial stop.

[0061] Specifically, the induced voltage detection unit 44 detects the induced voltage of the motor 20 in a state where the PWM output to the three-phase inverter (power conversion device 131) is stopped. In Fig. 11, the induced voltage of the VW phase is detected.

[0062] Furthermore, clutch mechanism 9 engages washing and spin-drying tub 7 to enable transmission of rotational force between motor 20, and PWM signal generator 43 outputs a PWM signal to rotate washing and spin-drying tub 7 at a predetermined speed, after which the PWM signal output is stopped. Induced voltage detector 44 detects the induced voltage during inertial rotation of motor 20 when washing and spin-drying tub 7 comes to an inertial stop.

[0063] The rotation speed detector 45 generates pulse signals based on the induced voltage of each phase detected by the induced voltage detector 44, and detects the rotation speed of the motor 20 by counting the number of pulse signals related to the generated pulse signals.

[0064] If the number of pulse signals is equal to or greater than a predetermined threshold, the mating determination unit 46 determines that the mating operation is normal. The mating determination unit 46 includes a notification means for notifying the abnormality of the mating operation when it determines that the mating operation is abnormal. The notification means may, for example, sound a buzzer, display an error code, or cut off the power. The notification means may also notify a mobile information terminal constituting a higher-level system or home security system via the communication I / F 983 shown in FIG. 2.

[0065] FIG. 12 is a circuit diagram showing a detailed configuration of the induced voltage detector 44 and the rotation speed detector 45 that utilize an induced voltage. In FIG. 12, the induced voltage detection unit 44 provides ladder resistors between the V-phase and W-phase signal lines and the ground, and detects the induced voltage of the VW phase based on the voltage division ratio of the ladder resistors. The rotation speed detection unit 45 includes a comparator made up of an operational amplifier that compares the induced voltage of the VW phase from the induced voltage detection unit 44, an input protection circuit, a pull-up resistor, a pull-down resistor, a noise removal capacitor, and the like.

[0066] 12 switches the input signal to the control unit 40 between HIGH and LOW when the induced voltages of the V and W phases match. The signal generated by the HIGH / LOW switching is a pulse signal based on the induced voltage of each phase. The number of HIGH / LOW switching events per unit time, i.e., the number of pulse signals per unit time, indicates the rotation speed of the motor 20, and the rotation speed of the motor 20 can be detected. The control unit 40 is configured by the computer shown in FIG. 2, and captures HIGH / LOW signals using an input capture function.

[0067] <Configuration Example 2 of Induced Voltage Detector 44 and Rotational Speed ​​Detector 45> FIG. 13 is a diagram showing the detailed configuration of an induced voltage detector 44A that uses an induced voltage and a rotation speed detector 45A. The induced voltage detector 44A and the rotation speed detector 45A shown in Fig. 13 are realized by the internal functions of the control unit 40 shown in Fig. 2. That is, the control unit 40 (Figs. 1 and 2) includes therein the induced voltage detector 44A and the rotation speed detector 45A. The induced voltage detector 44A includes an AD converter 47 that converts the input of the induced voltage of each phase into a digital signal. The rotation speed detection unit 45A detects the rotation speed through software processing (rotation speed detection function) of the control unit 40 (FIGS. 1 and 2).

[0068] The rotation speed detection unit 45A (rotation speed detection function) of the control unit 40 converts the induced voltage of each phase into an AD signal and directly takes it in. Then, the rotation speed detection unit 45A compares the induced voltages between the two phases and calculates the rotation speed (number of pulses) from the comparison result of the induced voltages between the two phases. In Fig. 13, the rotation speed detection unit 45A performs all internal software processing from the comparison of the induced voltages between the two phases to the calculation of the rotation speed (number of pulses).

[0069] FIG. 14 is a diagram showing an example of the circuit configuration of the AD converter 47. The AD converter 47 shown in FIG. 14 includes a sample-and-hold circuit 471 that holds an input signal, a comparator 472 consisting of an operational amplifier that compares two input signals, a successive approximation register 473 that counts the comparison results of the comparator 472, and a DA converter 474 that converts the output of the successive approximation register 473 into an analog signal and returns it to the input terminal (+ terminal) of the comparator 472.

[0070] Two methods (Configuration Example 1 (FIG. 12) and Configuration Example 2 (FIG. 13)) for detecting rotation speed based on induced voltage have been described above, but the method for calculating the rotation speed is not limited as long as it detects the rotation speed of motor 20 based on induced voltage.

[0071] The operation of the motor control device 100 of the first embodiment configured as described above will now be described. <Background> In control using a Hall sensor, the engagement of the clutch mechanism and the stop of the motor are determined using the Hall sensor signal. However, with sensorless control, these determinations may not be possible. This embodiment makes it possible to determine the engagement of the clutch mechanism and the stop of the motor based on the induced voltage of the motor.

[0072] <Detection of rotation speed based on induced voltage> First, the detection of the rotation speed based on the induced voltage will be described. The motor control device 100 (FIG. 1) includes an induced voltage detection unit 44 and a rotation speed detection unit 45. The rotation speed detection unit 45 outputs a HIGH / LOW signal (a pulse signal based on the induced voltage of each phase) according to the magnitude relationship between the induced voltages of the V phase and the W phase during inertial rotation of the motor, and the control unit 40 calculates the rotation speed of the motor 20 from the HIGH / LOW signal.

[0073] FIG. 15 is a diagram showing the relationship between the induced voltage of each phase and the output of the phase detector when the motor rotation direction is CCW (see FIG. 4 for the definition). In the figure, Eu: U-phase induced voltage, Ev: V-phase induced voltage, Ew: W-phase induced voltage, Ev-w: VW-phase induced voltage, and out (thin dashed line): output signal. The rising edge of the output signal out has a phase angle of 270°, and the falling edge has a phase angle of 90°. As shown in Figure 15, a HIGH / LOW signal is output based on the magnitude relationship between the V-phase and W-phase induced voltages, specifically, at the point where the V-phase induced voltage Ev and the W-phase induced voltage Ew intersect. A HIGH signal is output at the rising point (symbol x in Figure 15) where the V-phase induced voltage Ev and the W-phase induced voltage Ew intersect, and a LOW signal is output at the falling point (symbol y in Figure 15) where the V-phase induced voltage Ev and the W-phase induced voltage Ew intersect. The cycle of the HIGH signal output is the period indicated by arrows (2), (4), and (6) in Figure 15, and the cycle of the LOW signal output is the period indicated by arrows (1), (3), and (5) in Figure 15.

[0074] As can be seen from FIG. 15, the period of the HIGH / LOW signal output (the period indicated by arrows (1)-(6) in FIG. 15), which is based on the induced voltage of each phase, correlates with the rotation speed of the motor 20. That is, if the period of the HIGH / LOW signal output is short, the rotation speed (rotational speed) of the motor 20 is high, and if the period of the HIGH / LOW signal output is long, the rotation speed of the motor 20 is low. In this way, the control unit 40 of the motor control device 100 (FIG. 1) counts the HIGH / LOW signals to calculate the rotation speed of the motor 20. Here, the time from the rising edge to the falling edge of the HIGH / LOW signal is the 180-degree time. If the calculated rotation speed is extremely low, it is considered to be in a stopped state.

[0075] <Clutch mechanism fit determination> Next, the engagement determination of the clutch mechanism will be described. In the conventional example, if the number of signals from the position sensor (Hall element) exceeds a predetermined threshold at a specific timing, it is determined that the lower engagement operation (engagement operation that can transmit the rotational force of the motor to the washing tub) is normal. However, with the position sensorless system, it is not possible to determine whether the clutch mechanism 9 (the part that switches the destination of the rotational force of the motor 20, which drives the agitator blade 4 and washing tub 3) is engaged.

[0076] The motor control device 100 (FIG. 1) uses the induced voltage described above to make it possible to determine whether the clutch mechanism 9 is engaged even when the motor 20 is controlled without a position sensor.

[0077] 16 is a flowchart of the mating abnormality determination process of the motor control device 100 (FIG. 1). The flow of FIG. 16 is repeatedly executed by the control unit 40 (FIGS. 1 and 2) at predetermined intervals. This program starts when the dehydration process begins. In step S11, control unit 40 controls clutch mechanism 9 (FIG. 3) to perform a process for enabling the power transmission between washing and spin-drying tub 7 (FIG. 3) and motor 20 (drive motor) (FIG. 3). In the process for enabling the power transmission, clutch mechanism 9 connected to motor 20 is switched (lower engagement). The lower engagement operation is an engagement operation that allows the rotational force of motor 20 to be transmitted to washing tub 3 (FIG. 3). As a result, vertical washing machine 200 transitions to the spin-drying process, and both washing tub 3 (FIG. 3) and agitator blade 4 are rotated to spin-dry laundry by centrifugal force. If the engagement is normal, the inertia increases compared to the state before engagement, and the inertial rotation time is extended, whereas if the engagement is abnormal, the inertial rotation time is shortened.

[0078] In step S12, control unit 40 starts PWM output to rotate washing / spin-drying tub 7 (FIG. 3) and control it to rotate at a constant speed. This constant speed control is executed in the "position sensorless mode" shown in FIG.

[0079] In step S13, control unit 40 stops the PWM output and acquires the number of pulse signals based on the induced voltage when washing and spin-drying tub 7 comes to a coasting stop. That is, control unit 40 stops the PWM output, and when washing and spin-drying tub 7 comes to a coasting stop, induced voltage detection unit 45 detects the induced voltage and acquires the number of pulse signals based on the induced voltage. Obtaining the number of pulse signals means taking in pulse signals based on the induced voltage shown in Figures 10 to 14. In the conventional example, if the number of signals from the Hall element exceeds a predetermined threshold, it is determined that the lower fitting operation is normal, but in this embodiment, even in the case of position sensorless control, it is possible to determine whether the clutch mechanism 9 is fitted by obtaining the number of pulse signals based on the induced voltage.

[0080] In step S14, the fit determination unit 46 of the control unit 40 determines whether the number of pulse signals based on the induced voltage is equal to or greater than a predetermined threshold (number of pulse signals based on the induced voltage≧predetermined threshold). The predetermined threshold is, for example, the number of pulse signals “4.”

[0081] If the number of pulse signals based on the induced voltage is equal to or greater than the predetermined threshold value "4" (S14: Yes), it is determined to be normal (the clutch mechanism 9 is properly engaged by rotating the motor 20), and the process proceeds to step S15.

[0082] In step S15, the fitting determination unit 46 determines whether the lower fitting is complete. In step S16, the control unit 40 executes the "spin-drying process" and ends the processing of this flow.

[0083] On the other hand, if the number of pulse signals based on the induced voltage is smaller than the predetermined threshold value "4" in step S14 (S14: No), the engagement determination unit 46 determines that there is a possibility of an abnormality (the clutch mechanism 9 is not properly engaged) and proceeds to retry step S17.

[0084] In step S17, the fit determination unit 46 determines whether the number of retries is a predetermined number (number of retries≧predetermined number). The number of retries is, for example, 25 times.

[0085] If the number of retries is less than the predetermined number (S17: No), in step S18, the fit determination unit 46 increments the number of retries (number of retries + 1) and returns to step S12. After returning to step S12 and executing the processes of steps S12 to S14, if the number of pulse signals based on the induced voltage in step S14 is equal to or greater than the predetermined threshold value "4," the result is "normal," but if it is less than that, the above process is repeated until the number of retries reaches "25."

[0086] If the number of retries is equal to or greater than the predetermined number in step S17 (S17: Yes), it is determined that an abnormality has occurred (the clutch mechanism 9 is not properly engaged), and the engagement determination unit 46 issues a "mating abnormality notification" in step S19. The notification may be, for example, sounding a buzzer, displaying an error code, or cutting off the power.

[0087] In step S20, the control unit 40 automatically turns off the power supply to the vertical washing machine 200 after a predetermined time has elapsed (for example, after 60 minutes has elapsed), and ends the processing of this flow.

[0088] The above has described the mating abnormality determination using the pulse signal number acquisition (rotation number detection) based on the induced voltage. In addition to the above-mentioned mating abnormality detection, pulse signal count acquisition (rotation count detection) based on induced voltage can also be used to It can also be used to determine the state (rotating or stopped) of the motor 20. Hereinafter, "determining the state of the motor" using the number of pulse signals based on the induced voltage will be described.

[0089] <Motor status determination> This section describes the issues related to determining the motor status. When determining the motor state (rotating or stopped) using a pulse signal based on the induced voltage, if the motor current wire is broken, the pulse signal based on the induced voltage cannot be obtained even if the motor 20 is in operation (i.e., the motor 20 is rotating). In addition to wire breakage, breaks in the motor current wire can also be caused by a loose connector, etc. If a pulse signal based on the induced voltage cannot be obtained, the stopped state of the motor 20 may be erroneously determined or it may become impossible to determine the stopped state. Such an erroneous determination or inability to determine the stopped state may cause a hindrance to product safety (PS) related to the rotation operation (such as releasing the lid lock during rotation).

[0090] <Motor disconnection detection> In this embodiment, in consideration of the case where a pulse signal based on an induced voltage cannot be obtained, a specification is added in which a disconnection of the motor 20 is detected by flowing a direct current after it is determined that the motor has stopped. That is, when induced voltage detection unit 44 cannot detect induced voltage during coasting of motor 20, current control unit 42 of control unit 40 of motor control device 100 (FIG. 1) passes a predetermined DC current through the power lines to determine a disconnection of motor 20. This makes it possible to distinguish whether the cause of the disappearance of the pulse signal based on the induced voltage is a disconnection of motor 20 or whether motor 20 has stopped normally.

[0091] 17A and 17B are diagrams schematically showing three-phase current values ​​during normal operation and during disconnection while the motor is rotating. As shown in FIG. 17A, when motor 20 is normal, the three-phase current values ​​are out of phase with each other by 120 degrees.

[0092] As shown in the left diagram of FIG. 17B, when one phase is broken (here, when the V phase is broken), the current in the broken phase (in this case, the V phase) becomes 0A. As shown in the right diagram of FIG. 17B, when three phases are disconnected, the current is 0 A in all three phases with the U and W phases in phase. As such, there are two types of wire breaks: one-phase breaks and three-phase breaks. In both cases, the current in one of the three phases will be 0A. This characteristic can be used to determine whether a wire break has occurred.

[0093] <Motor disconnection detection details> FIG. 18 is a diagram illustrating a configuration example of an ACR (current controller). The ACR (current controller) shown in Fig. 18 includes the current control unit 42 of Fig. 10, a DC motor control unit (DC Motor) 98, and an LPF (low pass filter) 99 arranged in a feedback loop of the motor current. The LPF 99 has a filter characteristic whose cutoff frequency is the electrical time constant T of the motor. The α-phase current command value Iα* of the current control unit 42 shown in Figure 10 is replaced with the command current Id* in the ACR shown in Figure 18, the α-phase current detection value Iα of the current control unit 42 shown in Figure 10 is replaced with the current detection value IdFb in the ACR shown in Figure 18, and the α-phase voltage command value Vα* of the current control unit 42 shown in Figure 10 is replaced with the PI control output command current Id** in the ACR shown in Figure 18.

[0094] The PI control output command current Id** of the current control unit 42 shown in FIG. 10 is input to a DC motor control unit 98, which generates a motor current based on Id**.

[0095] 19 is a diagram showing the motor current of the DC motor control unit 98. The horizontal axis represents time, and the vertical axis represents the motor current value. As shown in Figure 19, the motor current increases almost linearly between times 0.4 and 0.6 in Figure 19. However, a current limiter is provided, and the ACR saturates the motor current at "7 A" after time 0.6.

[0096] <Motor disconnection detection operation> The operation of determining whether the motor 20 is disconnected will now be described in detail. If the PI control output command current Id**, which is the output of the ACR (Fig. 18) at the time positioning is completed, is equal to or greater than a certain threshold, it is determined that a break has occurred in the motor 20 (Fig. 1). The ACR control outline is to calculate and output Id** using PI control from the deviation between the command current Id* and the current detection value IdFb. If the motor 20 is broken, even if the command current Id* flowing to the U phase is normal, the detected current value will differ from IdFb because the current that physically flows will change due to the break. In ACR (Fig. 18), the I term of the PI control will continue to accumulate in order to eliminate the deviation between Id* and IdFb. When the motor 20 is in a disconnection state, the deviation between the command current Id* and the detected current value IdFb does not disappear, and the I control of the PI control accumulates, and theoretically Id** becomes infinity. This characteristic is used to determine whether the motor is disconnected.

[0097] [Effects of the first embodiment] First effect The motor control device 100 of the first embodiment includes an induced voltage detection unit 44 that detects the induced voltage of the motor 20 when the output of the power conversion device 131 is stopped, a rotation speed detection unit 45 that generates pulse signals based on the detected induced voltage of each phase and counts the number of pulse signals related to the pulse signals to detect the rotation speed of the motor 20, and a mating determination unit 46 that determines that the mating operation for switching the destination of the rotational force of the motor 20 is normal if the number of pulse signals is equal to or greater than a predetermined threshold.

[0098] Sensorless control, which does not use a hall sensor, cannot detect the rotor phase, so switching between synchronous operation and sensorless control may fail. In this case, backlash noise may occur from the gears inside the clutch mechanism 9 (Fig. 3) or vibration may occur in the washing / spinning tub 7 (Fig. 3).

[0099] The motor control device 100 of the first embodiment can detect the rotation speed of the motor 20 based on a pulse signal generated by an induced voltage, even in synchronous operation and sensorless control. This allows for accurate determination of the engagement of the clutch mechanism 9. Since accurate determination of the engagement of the clutch mechanism 9 can be performed, damage to the gears can be prevented.

[0100] In motor control device 100, induced voltage detection unit 44 detects the induced voltage during inertial rotation of motor 20 when PWM signal generation unit 43 stops outputting the PWM signal and washing and spin-drying tub 7 comes to an inertial stop.

[0101] In the motor control device 100, the clutch mechanism 9 engages to enable the transmission of rotational force between the washing and spin-drying tub 7 and the motor 20, the PWM signal generation unit 43 outputs a PWM signal to rotate the washing and spin-drying tub 7 at a predetermined speed, and then stops outputting the PWM signal, and the induced voltage detection unit 44 detects the induced voltage during the inertial rotation of the motor 20 when the washing and spin-drying tub 7 comes to an inertial stop.

[0102] By doing this, clutch mechanism 9 performs the engagement operation, PWM signal generating unit 43 outputs a PWM signal to rotate washing and spin-drying tub 7 at a predetermined speed, and then stops outputting the PWM signal, so that motor 20 continues to rotate by inertial force even after power is cut off (motor 20 is rotating by inertia when washing and spin-drying tub 7 comes to a stop by inertia), and induced voltage can be generated in each phase. In other words, if the engagement is normal, inertia increases compared to the state before engagement, so the inertial rotation time is extended, and if the engagement is abnormal, the inertial rotation time is short.

[0103] In the motor control device 100, when the mating determination unit 46 determines that the mating operation is abnormal, the PWM signal generation unit 43 outputs a PWM signal to rotate the washing and spin-drying tub 7 at a predetermined speed, and then stops outputting the PWM signal. The induced voltage detection unit 44 performs a predetermined number of retries until it detects the induced voltage during the inertial rotation of the motor 20 when the washing and spin-drying tub 7 comes to an inertial stop, and when the number of retries reaches the predetermined number, operation is stopped.

[0104] By doing this, if the number of pulse signals based on the induced voltage is a predetermined threshold (for example, "4"), it can be immediately determined that the mating operation by the clutch mechanism 9 is normal, whereas if the number of pulse signals does not reach the predetermined threshold, retries can be repeated a predetermined number of times to more reliably determine whether the mating operation is normal or abnormal. That is, even if the number of pulse signals based on the induced voltage does not reach the predetermined threshold in the initial operation, it can be determined by retrying that the mating operation by the clutch mechanism 9 is normal, and in this case, operation of the vertical washing machine 200 can be continued. Although the present embodiment has been described with reference to a configuration in which mating is determined based on the number of pulse signals, the present invention is not limited to this. For example, mating may be determined by calculating the inertial rotation time based on the magnitude or frequency of the induced voltage.

[0105] Second effect In the motor control device 100, if the induced voltage detection unit 44 cannot detect the induced voltage during inertial rotation of the motor 20, the current control unit 42 passes a predetermined DC current through the power line and determines whether the motor 20 is disconnected.

[0106] In this way, it is possible to distinguish whether the reason for the disappearance of the pulse signal based on the induced voltage is a wire break in the motor 20 or the motor 20 has stopped normally.

[0107] In the motor control device 100, if the induced voltage detection unit 44 cannot detect the induced voltage during inertial rotation of the motor 20, the current control unit 42 determines that the motor 20 is broken when the current of any of the three phases continues to be close to zero.

[0108] By doing this, there are two types of breaks: one-phase breaks or three-phase breaks, but in both cases, the current of one of the phases will be 0A. Here, when one phase is broken, UW is in opposite phase, and when three phases are broken, UW is in phase. From this characteristic, it is also possible to determine whether the break is a one-phase break or a three-phase break.

[0109] In the motor control device 100, the current control unit 42 has an ACR (Automatic Current Regulation), and determines that a disconnection has occurred in the motor 20 when the PI control output command current of the ACR is equal to or greater than a certain threshold value.

[0110] In this way, when the motor 20 is broken, the detected current value IdFb differs from the current command value Id*. That is, when the motor is broken, the command current Id* flowing through the U phase is normal, but the break causes the physical current flow to change, and so the detected current value differs from IdFb. To eliminate the deviation between Id* and IdFb, the I term of the PI control continues to accumulate. When the motor 20 is in a broken state, the deviation between the command current Id* and the detected current value IdFb does not disappear, so the I term of the PI control accumulates, and theoretically Id** becomes ∞. This makes it possible to determine whether the motor is broken.

[0111] In the present embodiment, a configuration has been described in which disconnection detection is performed based on the output of the current control unit 42, but the present invention is not limited to this. For example, the current detection unit 41 may determine that a disconnection has occurred when it detects that one of the three phases continues to have a value close to zero.

[0112] (Second embodiment) A motor control device according to a second embodiment of the present invention will now be described. <Background> With sensorless control, which does not use Hall sensors, it is not possible to detect the rotor phase, so a direct current is passed to pull the rotor phase θd into the control phase θdc (positioning), and an induced voltage is generated by rotating the rotor using open-loop control (synchronous operation), after which sensorless control is switched to (Fig. 7). During positioning, when the phase difference Δθ between the control phase θdc and the actual phase θd is 180°, no torque is generated and the actual phase cannot be pulled into the control phase, which can result in a failure to switch to synchronous operation / sensorless control and loss of synchronism. In this embodiment, torque is generated during positioning, making it possible to pull in the actual phase θd.

[0113] 20 is a functional block diagram showing the configuration of a motor control device according to a second embodiment of the present invention, in which the same components as those in FIG. In the motor control device 100 of the second embodiment, a control unit 40A includes a positioning setting unit 48 that advances the control phase θdc during positioning. The positioning setting unit 48 includes a control phase setting unit 48a and a positioning current setting unit 48b. The control phase setting unit 48a increases the control phase θdc based on the instruction from the positioning setting unit 48. Based on the instruction from the positioning setting unit 48, the positioning current setting unit 48b increases the positioning current Idc until the positioning current Idc becomes the first positioning current I1 or the second positioning current I2 ("two-stage positioning").

[0114] <Torque generated during positioning> First, the torque generated during positioning will be described. FIG. 21 is an explanatory diagram of torque generated during positioning. The upper diagram of FIG. 21 is a current vector diagram showing current vectors and rotation axis coordinates, and the lower diagram of FIG. 21 is a diagram showing torque generated in the upper diagram of FIG. 21. In explaining FIG. 21, the same parts as in FIG. 6 are given the same reference numerals. Note that "during positioning" refers to the "positioning mode" of the startup sequence shown in FIG. 7.

[0115] Using the U phase as the reference, the rotational angle position (magnetic pole position) of the dc axis is defined as θdc. The dc axis rotates counterclockwise, and the control phase θdc, which is the magnetic pole position, can be obtained by integrating the rotation frequency (inverter frequency command value ω1). In the "positioning mode," the rotor is fixed at a predetermined fixed position by gradually increasing the direct current flowing through the motor windings by linearly increasing only the dc-axis current command from 0. At the control phase θdc of the current vector shown in the upper diagram of FIG. 21, no torque T is generated, as shown in the lower diagram of FIG. The torque T is expressed by the following equation (4) and equation (5) obtained by substituting the current vectors Id and Iq into equation (4).

[0116]

number

[0117] <Sensorless control> Sensorless control, which does not use Hall sensors, cannot detect the rotor phase. For this reason, a direct current is passed to pull the rotor phase θd into the control phase θdc ("positioning"), and an induced voltage is generated by rotating the rotor using open-loop control ("synchronous operation"), after which sensorless control is switched to ("position sensorless control").

[0118] However, when switching to the synchronous operation and sensorless control, the following problems may occur. 《Problem (1)》 In positioning, when the phase difference Δθ between the control phase θdc and the actual phase θd is 180°, no torque is generated and the actual phase cannot be pulled into the control phase, which may result in a failure to switch to synchronous operation / sensorless control and loss of synchronism. The problem (1) will be described below with reference to FIG.

[0119] Fig. 22 is an explanatory diagram of torque generated during positioning when the phase difference Δθ (circular arrow) between the control phase θdc (thick dashed arrow) and the actual phase θd (thick solid arrow) is 180°. The upper diagram of Fig. 22 is a current vector diagram showing the current vector and rotation axis coordinates when the phase difference Δθ between the control phase θdc and the actual phase θd is 180°, and the lower diagram of Fig. 22 is a diagram showing the torque generated in the upper diagram of Fig. 22. Note that the explanatory diagrams of torque generated during positioning in this embodiment in Figs. 25 to 27, which will be described later, will be written in the same way as the upper diagram of Fig. 22 and the lower diagram of Fig. 22.

[0120] When the phase difference (axis error) Δθ=-180[deg] between the control phase θdc=0[deg] and the actual phase θd=180[deg] shown in the upper diagram of Figure 22, no torque is generated and the actual phase θd cannot be pulled into the control phase θdc, as shown in the lower diagram of Figure 22.

[0121] 《Problem (2)》 When the motor constants satisfy the relationship (Ke > (Ld - Lq) × Idc * cosΔθ), the torque is small when the phase difference Δθ is near ±180°, reaches a maximum at a point within the range of -180 to 0° or 0 to 180° (for example, approximately ±100°), and is zero at 0°. A certain amount of torque is required to start rotating the shaft, but when the phase difference Δθ is near 180°, the torque obtained is small, so the current must be increased. If the current is increased, the maximum torque becomes excessive, and the rotor phase θd is suddenly pulled in.

[0122] FIG. 23 is a diagram illustrating torque generated during positioning when the positioning current Idc is small. As shown in the dashed-line box a in FIG. 23, when the positioning current Idc is small, the torque is small and the actual phase θd cannot be pulled into the control phase θdc.

[0123] FIG. 24 is an explanatory diagram of torque generated during positioning when the positioning current Idc is large. As shown in the dashed-line box b in FIG. 24, when the positioning current Idc is large, the torque becomes excessively large, and the actual phase θd is suddenly pulled into the control phase θdc.

[0124] In the vertical washing machine 200, the connection destination of the motor 20 is switched by the clutch mechanism 9 (FIG. 3), but sudden retraction can cause the following problems on the pulsator (the rotating blades at the bottom of the vertical washing machine 200) (not shown) side and the washing tub side. Pulsator side: Backlash noise of gears in clutch mechanism 9 due to sudden retraction Washing tub side: Because the inertia is large, the sudden pull-in does not attenuate, and the actual phase oscillates around the control phase, which may cause abnormal noise or discomfort to the user.

[0125] If the current is reduced to resolve these issues, the torque required to start rotating the shaft may not be obtained depending on the phase difference Δθ, and the actual phase θd may not be pulled in.

[0126] The operation of the motor control device 100 of the second embodiment configured as described above will now be described. A control unit 40A (FIG. 20) of a motor control device 100 according to the second embodiment includes a positioning setting unit 48 that advances the control phase θdc during positioning.

[0127] 25 to 27 are explanatory diagrams of torque generated during positioning in this embodiment. In explaining Fig. 25 to Fig. 27, the same notation as in the upper and lower diagrams of Fig. 22 will be used. With reference to FIGS. 25 to 27, the solution of the problem (1) will be described.

[0128] FIG. 25 is an explanatory diagram of torque generated during positioning when the phase difference (axis error) Δθ=−135[deg] between the control phase θdc=45[deg] and the actual phase θd=180[deg]. In FIG. 22, the phase difference Δθ between the control phase θdc and the actual phase θd was 180°, so no torque was generated and the actual phase θd could not be pulled into the control phase θdc. In this embodiment, the positioning setting unit 48 of the control unit 40A (FIG. 20) advances the control phase θdc during positioning. In FIG. 25, the control phase θdc is advanced by +45 degrees, and the phase difference (axis error) Δθ between the control phase θdc=45[deg] and the actual phase θd=180[deg] is set to Δθ=−135[deg] (upper diagram in FIG. 25).

[0129] By advancing the control phase θdc by +45 degrees, the phase difference (axis error) Δθ becomes 135 degrees, and torque is generated as shown by the black circle (●) in the lower diagram of Figure 25 (lower diagram of Figure 25).

[0130] FIG. 26 is an explanatory diagram of torque generated during positioning when the phase difference (axis error) Δθ=−90[deg] between the control phase θdc=45[deg] and the actual phase θd=135[deg]. In Fig. 25, the control phase θdc is advanced by +45 degrees to generate torque, so that the actual phase θd (thick solid arrow in the upper diagram of Fig. 26) is pulled into the control phase θdc (thick dashed arrow in the upper diagram of Fig. 26). Here, the control phase θdc = 45 [deg] remains the same as in the upper diagram of Fig. 25.

[0131] FIG. 27 is an explanatory diagram of torque generated during positioning when the phase difference (axis error) Δθ=0[deg] between the control phase θdc=45[deg] and the actual phase θd=45[deg]. As the state in which the actual phase θd is pulled into the control phase θdc in Figure 25 progresses and the actual phase θd and the control phase θdc match (top diagram in Figure 27), the torque becomes 0, as indicated by the black circle (●) in the bottom diagram in Figure 27.

[0132] The positioning setting unit 48 (Figure 20) of the control unit 40A advances the control phase θdc during positioning, thereby eliminating the state in which the phase difference Δθ is 180°, generating torque and making it possible to pull in the actual phase θd ("Solution to Problem (1)").

[0133] Next, with reference to FIGS. 28 to 35, the solution to <<Problem (2)>> will be described. Fig. 28 is a diagram showing the control sequence for two-stage positioning, in which the vertical axis represents the positioning current Idc, the actual phase θd, the control phase θdc, and the three-phase currents Iu, Iv, and Iw, and the horizontal axis represents time. The positioning current Idc has two positioning currents (a first positioning current I1 and a second positioning current I2) for two-stage positioning control. Times AF in FIG. 28 are used to explain the positioning control timing, and the torque generated during positioning corresponding to times AF is shown in FIGS. 29 to 34. That is, FIG. 29 is a diagram showing the torque generated during positioning at time A in FIG. 28, FIG. 30 is a diagram showing the torque generated during positioning at time B in FIG. 28, FIG. 31 is a diagram showing the torque generated during positioning at time C in FIG. 28, FIG. 32 is a diagram showing the torque generated during positioning at time D in FIG. 28, FIG. 33 is a diagram showing the torque generated during positioning at time E in FIG. 28, and FIG. 34 is a diagram showing the torque generated during positioning at time F in FIG. 28. It is assumed that the initial axis error is 160 degrees in the torques generated during positioning in FIGS.

[0134] Time A in Figure 28 FIG. 29 is an explanatory diagram of torque generated during positioning when the phase difference (axis error) Δθ=−160[deg] between the control phase θdc=0[deg] and the actual phase θd=160[deg]. In FIG. 29, as indicated by the black circles (●) in the lower diagram of FIG. 29, the torque is small and the actual phase θd cannot be pulled into the control phase θdc (upper diagram of FIG. 29).

[0135] Time B in Figure 28 FIG. 30 is an explanatory diagram of torque generated during positioning when the phase difference (axis error) Δθ=−130[deg] between the control phase θdc=30[deg] and the actual phase θd=160[deg]. As shown in the upper diagram of Figure 30, when the control phase θdc is advanced (advancing the control phase θdc counterclockwise), the torque increases (see the black circle (●) in the lower diagram of Figure 30). Incidentally, this is the same function as "advancing the control phase θdc during positioning" explained in Figures 25 to 27.

[0136] Time C in Figure 28 FIG. 31 is an explanatory diagram of torque generated during positioning when the phase difference (axis error) Δθ=20[deg] between the control phase θdc=90[deg] and the actual phase θd=110[deg]. As shown in the upper diagram of FIG. 31, when the actual phase θd is pulled in and the axis error Δθ approaches 0, the torque decreases (see the black circle (●) in the lower diagram of FIG. 31).

[0137] Time D in Figure 28 FIG. 32 is an explanatory diagram of torque generated during positioning at time D when the phase difference (axis error) Δθ=20[deg] between the control phase θdc=180[deg] and the actual phase θd=160[deg]. As shown in the upper diagram of Figure 32, when the control phase θdc is advanced to 180 degrees (see also time D in Figure 25), the actual phase θd cannot be fully pulled in because the torque is small (see the black circle (●) in the lower diagram of Figure 32).

[0138] Time E in Figure 28 FIG. 33 is an explanatory diagram of torque generated during positioning at time E when the phase difference (axis error) Δθ=20[deg] between the control phase θdc=180[deg] and the actual phase θd=160[deg]. In Figure 33, the phase difference (axis error) Δθ = 20 [deg] between the control phase θdc = 180 [deg] and the actual phase θd = 160 [deg] is the same as in Figure 32. Furthermore, as shown in the control sequence in Figure 25, control is executed to increase the positioning current Idc (step S25 in Figure 35 described later). As shown in the upper diagram of FIG. 33, increasing the positioning current Idc increases the torque (see the black circles (●) in the lower diagram of FIG. 33), and the actual phase θd can be pulled into the control phase θdc.

[0139] Time F in Figure 28 FIG. 34 is an explanatory diagram of torque generated during positioning when the phase difference (axis error) Δθ=0[deg] between the control phase θdc=180[deg] and the actual phase θd=180[deg]. As shown in the upper diagram of Figure 34, the control phase θdc and the actual phase θd are the same, and the phase difference (axis error) is 0. The positioning setting unit 48 (Figure 20) executes control to increase the positioning current Idc (step S25 in Figure 35 described later), and by increasing the positioning current Idc, the torque increases (see the black circle (●) in the lower diagram of Figure 34), and the actual phase θd can be pulled into the control phase θdc.

[0140] The positioning setting unit 48 (FIG. 20) of the control unit 40A advances the control phase θdc during positioning, thereby enabling the phase difference Δθ that cannot be pulled in with a small current to be pulled in (<<Solution to problem (2)>>).

[0141] <Flowchart> Fig. 35 is a flowchart showing the control of "advancing the control phase θdc during positioning" and two-stage positioning by the positioning setting unit 48. The flow of Fig. 35 is repeatedly executed by the control unit 40A (Fig. 20) at predetermined timings. When this program for advancing the control phase θdc during positioning starts, in step S21 the positioning current setting unit 48b of the positioning setting unit 48 (FIG. 20) of the control unit 40A increases the positioning current Idc.

[0142] In step S22, the positioning setting unit 48 determines whether the positioning current Idc is equal to or greater than the first positioning current I1 (see FIG. 28) (Idc≧I1). If the positioning current Idc is less than the first positioning current I1 (S22: No), the process returns to step S21, and the positioning current setting unit 48b increases the positioning current Idc until the positioning current Idc becomes the first positioning current I1.

[0143] If the positioning current Idc is equal to or greater than the first positioning current I1 (S22: Yes), in step S23, the control phase setter 48a of the positioning setter 48 increases the control phase θdc. This allows the control phase θdc to be advanced during positioning. For example, as shown in FIG. 25, the control phase θdc is advanced by +45 degrees (see the upper diagram of FIG. 25 and also time AD in FIG. 28). By advancing the control phase θdc by +45 degrees, the phase difference (axis error) Δθ becomes 135 degrees, and torque is generated (see the lower diagram of FIG. 25).

[0144] In step S24, the positioning setting unit 48 determines whether the control phase θdc is equal to or greater than the control end phase θend (θdc≧θend). If the control phase θdc is less than the control end phase θend (S24: No), the process returns to step S23 and the control phase θdc continues to increase (see time D in FIG. 28). If the control phase θdc is equal to or greater than the control end phase θend (S24: Yes), in step S25, the positioning current setting unit 48b of the positioning setting unit 48 increases the positioning current Idc from the first positioning current I1 to the second positioning current I2 (see FIG. 28). Note that in this embodiment, the first positioning current I1 is set to a constant value during the period from time A to time D in FIG. 28, but it does not have to be a constant value (see symbol c in FIG. 28).

[0145] In step S26, the positioning setting unit 48 determines whether the positioning current Idc is equal to or greater than the second positioning current I2 (see FIG. 28) (Idc≧I2). If the positioning current Idc is less than the second positioning current I2 (S26: No), the process returns to step S25, where the positioning current setting unit 48b increases the positioning current Idc until the positioning current Idc becomes the second positioning current I2. If the positioning current Idc is equal to or greater than the second positioning current I2 (S26: Yes), the process of this flow ends.

[0146] In this embodiment, the timing of the increase in the positioning current Idc and the increase in the control phase θdc are separated, but the timing does not have to be separated; for example, the increase in the control phase θdc can be started halfway through increasing the positioning current Idc to the first positioning current I1.

[0147] [Effects of the second embodiment] In a motor control device 100 (FIG. 20) of the second embodiment, a control unit 40A includes a positioning setting unit 48 that advances the control phase θdc during positioning. The positioning setting unit 48 includes a control phase setting unit 48a that increases the control phase θdc based on an instruction from the positioning setting unit 48, and a positioning current setting unit 48b that increases the positioning current Idc based on an instruction from the positioning setting unit 48 until the positioning current Idc becomes the first positioning current I1 or the second positioning current I2.

[0148] By doing this, by advancing the control phase θdc during positioning, the state in which the phase difference Δθ is 180° is eliminated, torque is generated, and the actual phase θd can be pulled in. As a result, positioning is possible regardless of the actual phase θd, and there is an effect that the motor can be started reliably.

[0149] Furthermore, by advancing the control phase θdc during positioning, it is possible to pull in even a phase difference Δθ that cannot be pulled in with a small current. This makes it possible to position without causing sudden pull-in no matter where the actual phase θd is, thereby suppressing noise generation and unstable operation. Theoretically, if it is advanced by 180°, maximum torque can be obtained regardless of the phase.

[0150] If the inertia is known, the positioning setting unit 48 may determine the speed at which the phase is advanced from the inertia.

[0151] (Third embodiment) A motor control device according to a third embodiment of the present invention will be described. <Background> Vector control using Hall sensors can constantly detect the rotor phase, so even when clothes stick to the tub after spin-drying and the pulsator (the rotating blades at the bottom of the washing machine) is fixed by the clothes, torque can be generated to loosen the clothes.

[0152] On the other hand, with sensorless control that does not use Hall sensors, the rotor phase cannot be detected, so a direct current is passed to pull the rotor phase into the control phase (positioning), and an induced voltage is generated by rotating the rotor using open-loop control (synchronous operation), and then sensorless control is switched on. However, when clothes are stuck around the tub and the pulsator is fixed by the clothes, the lock prevents positioning and synchronous operation, resulting in loss of synchronization and the inability to start the motor (sensorless control). When loss of synchronization occurs, the rotor vibrates, generating noise that may be uncomfortable for the user.

[0153] To enable motor startup (sensorless control), the motor must be able to rotate without being locked, at least during positioning and synchronization operations. In other words, by removing the clothes from the pulsator and releasing the locked state, the motor can be started (sensorless control), generating torque to loosen the clothes.

[0154] In this embodiment, when clothes are stuck around the tub after spin-drying, the pulsator is moved little by little during positioning and synchronization operation, gradually removing the clothes from the pulsator and enabling loosening operation through sensorless operation.

[0155] 36 is a functional block diagram showing the configuration of a motor control device according to a third embodiment of the present invention, in which the same components as those in FIG. The motor control device 100 of the third embodiment includes a peeling setting unit 49 that causes the control unit 40B to rotate the pulsator little by little in the forward and reverse directions during positioning and synchronization operation, so as to gradually peel the clothes off the pulsator. Here, if the operation for peeling off the clothes is performed by the operation for starting the motor, there is a possibility that the motor will lose synchronization and generate abnormal noise.

[0156] The operation of the motor control device 100 of the third embodiment configured as described above will now be described.

[0157] <Peeling process> Figure 37 is a diagram explaining the peeling process. As shown in the left diagram of Figure 37, in the conventional example with a Hall sensor, the process immediately shifts to the loosening process after the spinning process. On the other hand, in this embodiment shown in the right diagram of Figure 37, the process starts the peeling process after the spinning process, and then shifts to the loosening process via the peeling process.

[0158] FIG. 38 is a diagram showing the rotation speeds in the dehydration process and the loosening process in the case of "with Hall sensor" shown in the left diagram of FIG.

[0159] Figure 39 is a diagram showing the rotation speeds for the spin-drying process, peeling process, and loosening process in the "without Hall sensor" diagram on the right of Figure 37. As shown in Figure 39, the control sequence for the spin-drying process and loosening process is the same as that in Figure 38. In the peeling process shown in Fig. 39, the motor 20 repeatedly rotates forward and backward to move the pulsator little by little. In the peeling process shown in Fig. 39, parameter A, which determines how many electrical angle cycles are involved, is increased in increments of, for example, 0.5. The number of times this operation is repeated is set to a predetermined value N (for example, N=3).

[0160] <Details of the peeling process> Fig. 40 is a diagram for explaining the details of the peeling process of Fig. 39. The vertical axis represents the control phase [rad / s] and the rotation speed. In FIG. 40, N=3, A is increased by 0.5, and the rotation direction setting process is reversed each time. When A=0.5 on the left side of Figure 40, the control phase θdc is 0-π and the rotation speed is small forward and reverse rotations. A=0.5 corresponds to π of the control phase θdc.

[0161] When A=1.0 in the center of FIG. 40, the control phase θdc is π-(−π) and the rotation speed is forward and reverse. When A=1.5 on the right side of FIG. 40, the control phase θdc is 2π-(−π) and the rotation speed is a large forward / reverse rotation.

[0162] <Flowchart> FIG. 41 is a flowchart showing the details of the peeling process. When this program starts during positioning and synchronization operation, the separation setting unit 49 of the control unit 40B sets initial values ​​in step S31. The initial values ​​are set as follows: execution count = 0, and parameter A, which determines the number of electrical angle cycles, = initial value (e.g., 0.5).

[0163] In step S32, the separation setting unit 49 executes positioning and synchronization operation. Specifically, the separation setting unit 49 calculates the phase update amount (A × θcyc) during synchronization operation, and executes positioning and synchronization operation based on this phase update amount. θcyc is the phase (2π) equivalent to one electrical angle cycle.

[0164] In step S33, the peel setting unit 49 increments the execution count (execution count+1).

[0165] In step S34, the peel setting unit 49 determines whether the execution count is equal to or greater than a predetermined value N (for example, 3) (execution count≧N).

[0166] When the execution count is equal to or greater than a predetermined value N (S34: Yes), in step S35, the peeling setting unit 49 determines whether or not a parameter A for determining the number of electrical angle cycles is equal to or greater than a parameter X for determining up to how many electrical angle cycles to execute (A ≥ X). If A ≥ X (S35: Yes), the processing of this flow ends.

[0167] If A < X (S35: No), in step S36, the peeling setting unit 49 sets the execution count = 0, increases a parameter A for determining the number of electrical angle cycles (for example, +0.5), and proceeds to step S37. The process also proceeds to step S37 when the execution count is less than the predetermined value N in step S34 (S34: No).

[0168] In step S37, the peeling setting unit executes a rotation direction setting process and proceeds to step S32 above. Here, the rotation direction in the rotation direction setting process can be freely set. For example, (1) reverse the direction each time and repeat forward and reverse rotations. (2) Do not reverse the rotation direction when the parameter A is increased, and reverse it otherwise.

[0169] By executing the flow of FIG. 41 above, as shown in FIG. 39, a peeling process is executed between the dehydration process and the loosening process.

[0170] [Effect of the Third Embodiment] The motor control device 100 (FIG. 36) of the third embodiment includes a peeling setting unit 49 in which the control unit 40B rotates slightly forward and backward during positioning and synchronous operation, and gradually operates to peel clothes from the pulsator. For example, the energization for one electrical angle cycle is performed several times forward and backward, and then the energization for two electrical angle cycles is performed several times forward and backward, and the rotation by synchronous operation is gradually increased in this way.

[0171] By doing this, the clothes are gradually removed from the pulsator using the above operation, and the motor can rotate without locking within the rotation range of the positioning and synchronous operation required for sensorless operation, making sensorless operation possible and allowing the clothes to be loosened.

[0172] (Fourth embodiment) A motor control device according to a fourth embodiment of the present invention will be described. <Background> Vector control using Hall sensors controls by feeding back the rotor phase and speed detected by the Hall sensors, while sensorless control, which does not use Hall sensors, estimates the rotor phase and rotation speed from the motor current and controls it.

[0173] In vector control, Id and Iq are controlled by converting three-phase currents into two phases and rotating coordinates. In this case, it is common to change the q-axis current Iq, which contributes to torque, and set the d-axis current Id, which contributes to magnetic flux, to a 0A command.

[0174] When a motor accelerates or decelerates from a constant speed state, the torque must be reversed, so Iq changes from positive to negative. When changing from a decelerating state to an accelerating or constant speed state, Iq also changes from negative to positive. In these cases, when Iq crosses zero, the current flowing through the motor also crosses zero (because Id is 0). When the current is 0 or a small value, current detection is impossible or the S / N ratio deteriorates, which increases the estimation error of the rotor phase and rotation speed estimated from the current and makes it impossible to output torque correctly, which can result in abnormal noise or loss of synchronization. Also, at low speeds, the required torque is small so Iq becomes small, and the deterioration of the S / N ratio can cause similar problems.

[0175] In this embodiment, when the motor current becomes small due to acceleration / deceleration or low-speed rotation of the motor, causing the S / N ratio of current detection to deteriorate, applying Id suppresses the deterioration of the S / N ratio of current detection, making it possible to maintain control stability.

[0176] 42 is a functional block diagram showing the configuration of a motor control device according to a fourth embodiment of the present invention, in which the same components as those in FIG. In the motor control device 100 of the fourth embodiment, the current control unit 42 of the control unit 40C includes a current increase setting unit 42c.

[0177] The current increase setting unit 42c applies the d-axis current Id when the motor current becomes small due to acceleration / deceleration or low-speed rotation of the motor, resulting in a poor signal-to-noise ratio in current detection. Specifically, the current increase setting unit 42c intentionally applies Id when the q-axis current Iq crosses zero or when Iq is smaller than a certain value, thereby increasing the signal-to-noise ratio of current detection and suppressing a decrease in the estimation accuracy of the rotor phase and rotation speed.

[0178] Id is selected so that the signal-to-noise ratio is sufficient for current detection. Note that, although a negative value for Id reduces the applied voltage, if the dead time error voltage has a large effect, it is better to select a positive value. This makes it possible to avoid abnormal noise and loss of synchronization during acceleration / deceleration and low-speed rotation.

[0179] The operation of the motor control device 100 of the fourth embodiment configured as described above will now be described. Fig. 43 is a diagram showing the transition of the current command value, three-phase current, and rotation speed when decelerating from a constant speed and then operating at a constant speed again in a comparative example ("no current increase"). Fig. 43 shows an example where Id = 0. In addition, in this embodiment ("current increase") (Fig. 44), the current command value is similar when no current increase is performed.

[0180] FIG. 44 is a diagram showing the transition of the current command value, three-phase current, and rotation speed when decelerating from a constant speed and then operating at a constant speed again in this embodiment ("with current increase"). The current increase setting unit 42c applies Id when the motor current becomes small due to acceleration / deceleration or low-speed rotation of the motor, resulting in a poor S / N ratio in current detection (see symbol d in FIG. 44).

[0181] <Flowchart> FIG. 45 is a flowchart showing the Id setting control of the current increase setting unit 42c. This program is started when the motor current becomes small due to acceleration / deceleration or low-speed rotation of the motor, causing the signal-to-noise ratio of current detection to deteriorate. In step S41, the current increase setting unit 42c of the current control unit 42 of the control unit 40C determines whether or not a current increase is necessary.

[0182] An example of determining whether a current increase is necessary will be described. When the current amplitude calculated from the current command falls below a certain value (for example, a current value (1A) at which sensorless control becomes difficult) When the rotation speed command changes from (constant speed / acceleration) to (deceleration) When the sign of the q-axis current Iq is reversed When the rotation speed command falls below a certain value (low speed rotation) (for example, when it falls below 100 r / min)

[0183] If the current increase is necessary (S42: Yes), the current increase setting unit 42c sets the d-axis current command value Id* in step S42 and ends the processing of this flow. If the current increase is not necessary (S42: No), the current increase setting unit 42c sets the d-axis current command value Id* to 0 in step S43 and ends the processing of this flow.

[0184] An example of setting the Id application amount will be described. Fixed value (e.g., 1A) Calculate Id so that the current amplitude does not fall below a certain value. For example, calculate the value that makes the current amplitude 0.5 A according to the following equation (6).

[0185]

number

[0186] The value is determined according to the rotation speed command. For example, the value is determined according to the following formula (7), which is 1 A at 50 r / min and 0 A at 100 r / min. Id = -0.02 × rotation speed + 2 [A] ... Equation (7)

[0187] [Effects of the fourth embodiment] The motor control device 100 of the fourth embodiment includes a current control unit 42 of a control unit 40C that includes a current increase setting unit 42c that applies a d-axis current Id when the motor current becomes small due to acceleration / deceleration or low-speed rotation of the motor, deteriorating the signal-to-noise ratio of current detection.

[0188] By doing this, Id is intentionally passed when the q-axis current Iq crosses zero or when Iq is smaller than a certain value, which increases the signal-to-noise ratio of current detection and suppresses a decrease in the estimation accuracy of the rotor phase and rotation speed. This makes it possible to avoid abnormal noise and loss of synchronization during acceleration / deceleration and low-speed rotation.

[0189] As a secondary effect, washing machines generally have the characteristic that the load inertia changes depending on the amount of laundry. If a unique inertia setting value is set to simplify the control structure, that is, if the (setting value) is greater than the (actual value), the rotation speed control becomes high gain and the rotation speed oscillates. This causes the q-axis current Iq to oscillate and periodically cross zero, which may result in abnormal noise or loss of synchronization. Even in such cases, the method using the current increase setting unit 42c of this embodiment is effective.

[0190] The present invention is not limited to the above-described embodiments and modifications, and includes other modifications and applications as long as they do not deviate from the gist of the present invention as set forth in the claims. For example, the above-described embodiments have been described in detail to facilitate understanding of the present invention, and the present invention is not necessarily limited to those including all of the described configurations. Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, or to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is possible to add, delete, or replace part of the configuration of each embodiment with other configurations.

[0191] The motor control device 100 according to each of the above embodiments can be applied not only to washing machines but also to motor devices in which mechanical loads are driven by motors, such as electric compressors, electric vehicles, electric railway vehicles, ships, aircraft, and the like.

Explanation of Signs

[0192] 6 Housing 3 Washing tub 4 Stirring blade 7 Washing and dewatering tub 9 Clutch mechanism 20 Motor 40, 40A, 40B, 40C Control unit 41, 50 Current detection unit 42 Current control unit 42c Current increment setting unit 43 PWM signal generation unit 44 Induced voltage detection unit (pulse generation means) 45 Rotation speed detection unit 46 Fitting determination unit (notification means) 48 Positioning setting unit 48a Control phase setting unit 48b Positioning current setting unit 49 Peeling setting unit 100 Motor control device 120 DC voltage source 130 Power conversion unit 131 Power conversion device 200 Vertical washing machine (washing machine) θd Actual phase θdc Control phase Δθc Phase difference (axis error) Eu Induced voltage of U phase Ev Induced voltage of V phase w Induced voltage of W phase Ev-w Induced voltage of V-W phase Iu, Iv, Iw Three-phase current Id d-axis current Iq q-axis current Idc Positioning current I1 First positioning current I2 Second positioning current T Generated torque J judgment signal ACR current controller (current control section) S13: A step of detecting an induced voltage of the motor while the output of the power conversion device is stopped. S13: generating a pulse signal based on the detected induced voltage of each phase, and counting the number of pulse signals related to the pulse signal to detect the number of rotations of the motor; S15: A step of determining that the engagement operation for switching the destination of the rotational force of the motor is normal when the number of pulse signals is equal to or greater than a predetermined threshold value.

Claims

1. A motor control device including a power conversion device that supplies AC power to a motor, an induced voltage detection unit that detects an induced voltage of the motor in a state where the output of the power conversion device is stopped; a rotation speed detection unit that detects the rotation speed of the motor based on the detected induced voltage of each phase; and a fitting determination unit that determines whether the fitting operation for switching the destination of the rotational force of the motor is normal based on the detected induced voltage of each phase. A motor control device characterized by:

2. the induced voltage detection unit includes a pulse generation means for generating a pulse signal based on the detected induced voltage of each phase, The rotation speed detection unit detects the rotation speed of the motor based on the pulse signal.

2. The motor control device according to claim 1.

3. the induced voltage detection unit includes a pulse generation means for generating a pulse signal based on the detected induced voltage of each phase, The mating determination unit determines whether a mating operation for switching a destination of rotational force of the motor is normal when the number of pulse signals is equal to or greater than a predetermined threshold based on the pulse signals.

2. The motor control device according to claim 1.

4. a PWM signal generating unit that compares an AC voltage command with a PWM carrier wave to generate a PWM signal, and generates a control signal for controlling the power conversion device based on the PWM signal; The induced voltage detection unit detects the induced voltage when the PWM signal generation unit stops outputting the PWM signal and the motor is inertially rotating.

2. The motor control device according to claim 1.

5. a clutch mechanism that switches the destination of the rotational force of the motor by a fitting operation that can transmit the rotational force of the motor to the washing and spin-drying tub; the clutch mechanism engages with the washing and spin-drying tub to enable transmission of rotational force between the motor and the washing and spin-drying tub, the PWM signal generator outputs a PWM signal to rotate the washing and spin-drying tub at a predetermined speed, and then stops outputting the PWM signal; The induced voltage detection unit detects the induced voltage during inertial rotation of the motor when the washing and spin-drying tub comes to an inertial stop.

5. The motor control device according to claim 4.

6. When the fitting determination unit determines that the fitting operation is abnormal, The PWM signal generating unit outputs a PWM signal to rotate the washing and spin-drying tub at a predetermined speed, and then stops outputting the PWM signal; The induced voltage detection unit executes a retry a predetermined number of times until the induced voltage during the inertial rotation of the motor is detected when the washing and spin-drying tub comes to an inertial stop; When the number of retries reaches a predetermined number, operation stops.

6. The motor control device according to claim 5.

7. The fitting determination unit includes a notification unit that notifies the user of an abnormality in the fitting operation when the fitting determination unit determines that the fitting operation is abnormal.

2. The motor control device according to claim 1.

8. a current control unit that outputs a control command value for controlling a current flowing through the motor; When the induced voltage detection unit cannot detect the induced voltage during inertial rotation of the motor, the current control unit causes a predetermined DC current to flow through the power line and determines whether the motor is disconnected.

2. The motor control device according to claim 1.

9. a current control unit that outputs a control command value for controlling a current flowing through the motor; When the induced voltage detection unit cannot detect the induced voltage during inertial rotation of the motor, the current control unit determines that the motor is disconnected when the current of any of the three phases continues to be close to zero.

2. The motor control device according to claim 1.

10. a current control unit that outputs a control command value for controlling a current flowing through the motor; If the output of the current control unit is equal to or greater than a certain threshold, it is determined that a wire break has occurred in the motor.

2. The motor control device according to claim 1.

11. The clutch mechanism rotates the agitator while the washing and spin-drying tub is stationary, or switches the destination of transmission of the rotational force of the motor by the engaging operation, and rotates the washing and spin-drying tub and the agitator integrally in the same direction.

6. The motor control device according to claim 5.

12. Washing and spinning tub, a rotatable agitating blade provided in the washing and spin-drying tub; a motor that rotates the washing and spin-drying tub and the agitating blade; a clutch mechanism that switches the destination of the rotational force of the motor by a fitting operation that can transmit the rotational force of the motor to the washing and spin-drying tub; A washing machine comprising a motor control device, The motor control device is a motor control device according to any one of claims 1 to 11. A washing machine characterized by:

13. A position sensorless motor control method for a motor control device including a power conversion device that supplies AC power to a motor, comprising: The motor control device includes: detecting an induced voltage of the motor in a state in which the output of the power conversion device is stopped; generating pulse signals based on the detected induced voltages of the respective phases, and counting the number of pulse signals to detect the number of rotations of the motor; If the number of pulse signals is equal to or greater than a predetermined threshold, determining that the fitting operation for switching the destination of transmission of the rotational force of the motor is normal. A position sensorless motor control method comprising:

Images