Garment processing machine and processing method

Abstract

The objective is to provide a garment processing machine that can correctly determine when a DC brushless motor has stopped, even when its rotational position is unknown. [Solution] The garment processing machine of the embodiment includes a control unit that performs sensorless drive of a motor and applies a brake, an acquisition unit that acquires the current flowing to the motor at predetermined time intervals for a first predetermined number of times while the brake is applied, and a determination unit that determines that the motor is stopped when the acquisition unit determines that the current value of the most recent predetermined number of currents acquired is less than or equal to a predetermined value for a second predetermined number of times.

Description

Technical Field

[0001] Embodiments of the present invention relate to a clothing treatment machine and a treatment method.

Background Art

[0002] Among clothing treatment machines (washing machines, washer-dryers, dryers), a DC brushless motor may be used. When estimating the speed (rotation speed) of a sensorless DC brushless motor, if a problem such as out-of-step occurs, it becomes difficult to estimate the speed (rotation speed) of the DC brushless motor.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The problem to be solved by the present invention is to provide a clothing treatment machine capable of correctly determining the stop of a DC brushless motor even when the rotational position of the DC brushless motor is unknown.

Means for Solving the Problems

[0005] The clothing treatment machine according to the embodiment includes a control unit, an acquisition unit, and a determination unit. The control unit performs control to apply a brake to a sensorless-driven electric motor that does not use a sensor for detecting a rotational position. The acquisition unit acquires a current of one phase of three-phase currents flowing through the electric motor at a predetermined time interval a predetermined number of times or more while the brake is being applied. The determination unit determines that the electric motor has stopped when it is determined that the number of currents exceeding a predetermined value among the most recent predetermined number of currents acquired by the acquisition unit is less than or equal to a predetermined number.

Brief Description of the Drawings

[0006] [Figure 1] A diagram showing an example of the configuration of a garment processing machine according to an embodiment. [Figure 2] A diagram showing an example of the drive control system for each motor in the garment processing machine of the embodiment. [Figure 3] A first diagram showing the processing flow of the garment processing machine according to the embodiment. [Figure 4] A second diagram showing the processing flow of the garment processing machine according to the embodiment. [Figure 5] A third diagram showing the processing flow of the garment processing machine according to the embodiment. [Figure 6] Figure 1 illustrates the determination of whether the drum motor stops in the garment processing machine of the embodiment. [Figure 7] A second figure illustrating the determination of whether the drum motor stops in the garment processing machine of the embodiment. [Figure 8] A third figure illustrating the determination of the drum motor stop function in the garment processing machine of the embodiment. [Figure 9] A diagram showing an example of a low-pass filter according to the first modified embodiment. [Figure 10] A figure showing an example of the current value of the U-phase current in a second modified example of the embodiment. [Modes for carrying out the invention]

[0007] The garment processing machine of the embodiment will be described below with reference to the drawings. In the following description, components having the same or similar functions will be denoted by the same reference numerals. Duplication of these components may be omitted. "Based on XX" means "based on at least XX," and may also include cases based on other elements in addition to XX. "Based on XX" is not limited to cases where XX is used directly, but may also include cases where calculations or processing have been performed on XX. "XX or YY" is not limited to cases where either XX or YY is used, but may also include cases where both XX and YY are used. This is also true when there are three or more selective elements. "XX" and "YY" are arbitrary elements (e.g., arbitrary information). Furthermore, "detection" is not limited to cases where the physical quantity of the object is directly sensed, but may also include cases where other physical quantities related to the physical quantity of the object are directly or indirectly acquired, and the physical quantity of the object is estimated or identified from the acquired other physical quantities. Furthermore, "acquisition" is not limited to cases where the object (including information) itself is directly received, but may also include cases where the directly received object (including information) becomes the object through calculations or processing.

[0008] In this disclosure, "to acquire" is not limited to actively acquiring information by sending a transmission request, but may also include acquiring information by passively receiving information transmitted from other devices or equipment. Furthermore, "to acquire" is not limited to directly acquiring information from other devices or equipment, but may also include acquiring information indirectly through yet another device or equipment. Moreover, "to acquire" is not limited to directly acquiring the target information (information to be acquired) from an external source, but may also include generating and acquiring the target information by performing calculations or processing on information obtained from an external source.

[0009] In this disclosure, “communicate” is not limited to directly sending and receiving information, but may also include cases where information is sent and received as a result via other devices or equipment. In this disclosure, “use XX” is not limited to directly using XX, but may also include cases where XX is used as a result via other devices or equipment.

[0010] <Embodiment> (Overall configuration of the garment processing machine) The garment processing machine 100 of the embodiment will be described with reference to the figures. In this embodiment, a drum-type washer-dryer will be used as an example of the garment processing machine 100. Figure 1 is a diagram showing an example of the configuration of the garment processing machine 100 of the embodiment. The outer casing 1 is hollow and has a front plate, a rear plate, a left plate, a right plate, a bottom plate, and a top plate. A through-hole-shaped entrance / exit 2 is formed in the front plate of the outer casing 1. A door 3 is attached to the front plate of the outer casing 1. This door 3 can be operated by the user from the front between a closed state and an open state. When the door 3 is closed, the entrance / exit 2 is closed, and when the door 3 is open, the entrance / exit 2 is open. A water receiving tank 4 is fixed inside the outer casing 1. This water receiving tank 4 is cylindrical with a closed rear surface and is arranged in an inclined state with its axis CL sloping downward from front to rear. The front of this water receiving tank 4 is open, and when the door 3 is closed, the door 3 airtightly closes the front of the water receiving tank 4.

[0011] A drum motor 5 is fixed to the rear plate of the water receiving tank 4, located outside the water receiving tank 4. This drum motor 5 is a speed-controllable DC brushless motor, and its rotating shaft 6 protrudes into the water receiving tank 4. This rotating shaft 6 is positioned in conjunction with the axis CL of the water receiving tank 4, and a drum 7 is fixed to the rotating shaft 6, located inside the water receiving tank 4. This drum 7 is cylindrical with a closed rear surface and rotates integrally with the rotating shaft 6 when the drum motor 5 is operating. The front of this drum 7 faces the entrance / exit 2 from the rear via the front of the water receiving tank 4, and laundry is loaded and unloaded into the drum 7 from the front through the entrance / exit 2, the front of the water receiving tank 4, and the front of the drum 7 when the door 3 is open.

[0012] The drum 7 has multiple through holes 8, and the internal space of the drum 7 is connected to the internal space of the water receiving tank 4 through each of the multiple through holes 8. Multiple baffles 9 are fixed to the drum 7. Each of these baffles 9 moves in the circumferential direction around the axis line CL as the drum 7 rotates, and the laundry inside the drum 7 is agitated as it moves in the circumferential direction while getting caught on each of the baffles 9 before falling due to gravity.

[0013] A water supply valve 10 is fixed inside the outer casing 1. This water supply valve 10 has an inlet and an outlet, and the inlet of the water supply valve 10 is connected to a water tap. This water supply valve 10 is driven by a water supply valve motor 11 (see Figure 1), and the outlet of the water supply valve 10 is switched between an open state and a closed state depending on the rotation amount of the water supply valve motor 11. The outlet of this water supply valve 10 is connected to a water filling case 12. When the water supply valve 10 is open, tap water is injected into the water filling case 12 through the water supply valve 10, and when the water supply valve 10 is closed, tap water is not injected into the water filling case 12. This water filling case 12 is fixed inside the outer casing 1 at a higher position than the water receiving tank 4 and has a cylindrical water inlet 13. This water inlet 13 is inserted into the water receiving tank 4, and the tap water injected into the water filling case 12 from the water supply valve 10 is injected into the water receiving tank 4 from the water inlet 13.

[0014] The upper end of the drain pipe 14 is connected to the water receiving tank 4 at its lowest point, and a drain valve 15 is interposed in the drain pipe 14. This drain valve 15 is driven by a drain valve motor 16 (see Figure 1) and switches between an open state and a closed state depending on the rotation amount of the drain valve motor 16. When the drain valve 15 is closed, tap water injected into the water receiving tank 4 from the water inlet 13 is stored in the water receiving tank 4, and when the drain valve 15 is open, the tap water in the water receiving tank 4 is discharged to the outside of the water receiving tank 4 through the drain pipe 14.

[0015] On the bottom plate of the outer box 1, a main duct 17 is fixed below the water receiving tank 4. This main duct 17 is cylindrical and oriented in the front-rear direction. The lower end of the front duct 18 is connected to the front end of the main duct 17. This front duct 18 is cylindrical and oriented in the vertical direction, and the upper end of the front duct 18 is connected to the internal space of the water receiving tank 4 at the front end of the water receiving tank 4. A fan casing 19 is fixed to the rear end of the main duct 17. This fan casing 19 has a through-hole-shaped intake port 20 and a cylindrical exhaust port 21, and the internal space of the fan casing 19 is connected to the internal space of the main duct 17 through the intake port 20.

[0016] A fan motor 22 is fixed to the fan casing 19 and is located outside the fan casing 19. This fan motor 22 has a rotating shaft 23 that protrudes into the fan casing 19, and a fan 24 is fixed to the rotating shaft 23 and is located inside the fan casing 19. This fan 24 is a centrifugal type that sucks air axially and discharges it radially. The intake port 20 of the fan casing 19 faces the fan 24 axially, and the exhaust port 21 of the fan casing 19 faces the fan 24 radially.

[0017] The lower end of the rear duct 25 is connected to the exhaust port 21 of the fan casing 19. This rear duct 25 is cylindrical and oriented in the vertical direction, and the upper end of the rear duct 25 is connected to the internal space of the water receiving tank 4 at the rear end of the water receiving tank 4. These rear duct 25, fan casing 19, main duct 17, front duct 18, and water receiving tank 4 constitute an annular circulation duct 26 with the internal space of the water receiving tank 4 as the starting point and the ending point respectively. When the fan motor 22 is operating in the closed state of the door 3, based on the rotation of the fan 24 in a certain direction, the air in the water receiving tank 4 is sucked from the front duct 18 into the main duct 17 and then into the fan casing 19, and then returned from the fan casing 19 through the rear duct 25 into the water receiving tank 4.

[0018] Inside the outer box 1, a compressor 27 (compression machine) is fixed. This compressor 27 is arranged outside the circulation duct 26, and has a discharge port for discharging refrigerant and a suction port for sucking refrigerant. This compressor 27 uses a compressor motor 28 (refer to FIG. 2 described later) as a drive source, and the compressor motor 28 is composed of a speed-controllable DC brushless motor.

[0019] Inside the main duct 17, a condenser 29 is fixed. This condenser 29 heats air, and is constituted by fixing each of a plurality of plate-like heating fins 31 in contact with the outer peripheral surface of one refrigerant pipe 30 that meanders and bends in a serpentine shape. The refrigerant pipe 30 of this condenser 29 is connected to the discharge port of the compressor 27, and in the operating state of the compressor motor 28, the refrigerant discharged from the discharge port of the compressor 27 enters the refrigerant pipe 30 of the condenser 29.

[0020] FIG. 2 is a diagram showing an example of a drive control system for each motor in the clothing treatment machine 100 of the embodiment. Each motor shown in FIG. 2 is a drum motor 5, a fan motor 22, and a compressor motor 28. The inverter circuit 34 is constituted by connecting six IGBTs (Insulated Gate Bipolar Transistors) 35a to 35f (switching elements) in a three-phase bridge connection, and flywheel diodes 36a to 36f are connected between the collector-emitter of each IGBT 35a to 35f. Each phase output terminal of the inverter circuit 34 is connected to each phase winding of the drum motor 5. The inverter circuit 34 is an example of a drive circuit for driving the compressor motor 28.

[0021] The emitters of the IGBTs 35d, 35e, 35f on the lower arm side are connected to the ground via shunt resistors 37u, 37v, 37w. Also, the common connection point between the emitters of the IGBTs 35d, 35e, 35f and the shunt resistors 37u, 37v, 37w is connected to the input terminal of a control circuit 42A (microprocessor, microcomputer).

[0022] Internally, the control circuit 42A, although not shown in the diagram, is composed of an operational amplifier and other components, and a level shift circuit amplifies the terminal voltage of the shunt resistor 37u~37w, while also applying a bias (for example, 0 to +3.3V) so that the output range of the amplified signal falls within the positive side.

[0023] A similarly configured inverter circuit 38 and shunt resistors 39 (u, v, w) are provided for the fan motor 22, and an inverter circuit 40 and shunt resistors 41 (u, v, w) are provided for the compressor motor 28. The inverter circuits 38 and 40 are controlled by another control circuit 42B (an example of a microprocessor, microcomputer, or control unit), and the control circuits 42A and 42B are capable of bidirectional communication via serial communication.

[0024] A drive power supply circuit 43 is connected to the input side of inverter circuits 34, 38, and 40. The drive power supply circuit 43 is connected to a 100V AC power supply via a reactor 44 (inductive reactor) at one end and comprises a full-wave rectifier circuit 45 composed of a diode bridge, and two capacitors 46a and 46b connected in series to the output side of the full-wave rectifier circuit 45. The common connection point of capacitors 46a and 46b is connected to one of the input terminals of the full-wave rectifier circuit 45. Note that if the boost operation using the reactor 44 is not performed, the drive power supply circuit 43 may double the voltage of the 100V AC power supply and supply a DC voltage of approximately 280V to the inverter circuit 34, etc.

[0025] Another full-wave rectifier circuit 47, similarly composed of a diode bridge, is connected in parallel to the input terminal of the full-wave rectifier circuit 45, and an IGBT 48 is connected between the output terminals of the full-wave rectifier circuit 47. The on / off control of the IGBT 48 is performed by the control circuit 42B.

[0026] A series circuit of resistors 49a and 49b, and a series circuit of resistors 50a and 50b are connected between the input terminals of inverter circuits 34 and 38, respectively. The common connection points of these circuits are connected to the input terminals of control circuits 42A and 42B. Control circuits 42A and 42B detect the drive power supply voltage input to inverter circuits 34 and 38 by referring to the voltage at each of the common connection points.

[0027] Furthermore, a current sensor 52, such as a current transformer (CT), is interposed between the AC power supply and the reactor 44, and the sensor signal output by the current sensor 52 is supplied to the control circuit 42B.

[0028] Control circuit 42A detects the current flowing through each phase winding of the drum motor 5 using shunt resistors 37u, 37v, and 37w. Control circuit 42B also detects the current flowing through each phase winding of the fan motor 22 and compressor motor 28 using shunt resistors 39 and 41. Based on the detected current values, control circuits 42A and 42B estimate the phase θ and rotational angular velocity ω of the secondary rotating magnetic field, and obtain the excitation current component Id (i.e., d-axis current) and torque current component Iq (i.e., q-axis current), which are two-phase power currents, by performing orthogonal coordinate transformation (αβ transformation) and dq (direct-quadrature) coordinate transformation on the three-phase currents. When a speed command is given from an external source, control circuits 42A and 42B generate current commands Idref and Iqref based on the estimated phase θ and rotational angular velocity ω and current components Id and Iq, and then convert these into voltage commands Vd and Vq, performing orthogonal coordinate transformation and three-phase coordinate transformation. Ultimately, the drive signal is generated as a PWM (Pulse Width Modulation) signal and output to the respective phase windings of the drum motor 5, fan motor 22, and compressor motor 28 via inverter circuits 34, 38, and 40. When the drum motor 5 is braking while exceeding a predetermined rotational speed, the control circuit 42A uses regenerative braking. When the drum motor 5 is braking while below a predetermined rotational speed, the control circuit 42A uses short-circuit braking. Furthermore, when braking is applied, the control circuit 42A determines whether the drum motor 5 has stopped. Details of the drum motor 5 stopping determination process performed by the control circuit 42A will be described later.

[0029] In the above configuration, the inverter circuits 34, 38, and 40, the control circuits 42A and 42B, the drive power supply circuit 43, the reactor 44, the full-wave rectifier circuit 47, and the IGBT 48 constitute the drive unit 60.

[0030] Next, the details of the process for determining whether the drum motor 5 is stopped by the control circuit 42A of the embodiment will be described. Figure 3 is the first diagram of the processing flow of the garment processing machine 100 of the embodiment. Figure 4 is the second diagram of the processing flow of the garment processing machine 100 of the embodiment. Figure 5 is the third diagram of the processing flow of the garment processing machine 100 of the embodiment. Figure 6 is the first diagram for explaining the process for determining whether the drum motor 5 is stopped by the garment processing machine 100 of the embodiment. Figure 7 is the second diagram for explaining the process for determining whether the drum motor 5 is stopped by the garment processing machine 100 of the embodiment. Figure 8 is the third diagram for explaining the process for determining whether the drum motor 5 is stopped by the garment processing machine 100 of the embodiment. Here, the details of the process for determining whether the drum motor 5 is stopped by the control circuit 42A will be described with reference to Figures 3 to 8.

[0031] First, we will explain the process by which the garment processing machine 100 determines when the drum motor 5 shown in Figure 3 stops due to regenerative braking. The example shown here assumes that the door 3 is locked and the drum motor 5 is stopped by regenerative braking while it is rotating. The control circuit 42A is assumed to be able to obtain the rotor angle of the drum motor 5. Furthermore, the control circuit 42A switches from regenerative braking to short-circuit braking when the rotational speed falls below a predetermined level. Figure 6 shows an example of the change in the current of the drum motor 5 when it stops due to regenerative braking.

[0032] In Figure 6, R_Ia represents the U-phase current of the drum motor 5. Figure 6 also shows R_omega_I_32, R_Vdc_L, and S_stage along with R_Ia. R_omega_I_32 represents the estimated rotational speed of the drum motor 5. This estimated rotational speed is the speed estimated by the control circuit 42A based on the rotor angle. R_Vdc_L represents the lower limit of the bus voltage ripple fluctuation. S_stage represents the control process. The control process shown in Figure 6 includes three stages: rotation, regenerative braking, and stop determination. The horizontal axis represents time. The vertical axis represents amperes for R_Ia, rpm (Revolutions Per Minute) for R_omega_I_32, and volts for Vdc_L.

[0033] The control circuit 42A applies regenerative braking while the drum motor 5 is rotating (step S1). When regenerative braking is applied, the control circuit 42A acquires the U-phase current of the drum motor 5 at predetermined time intervals (step S2). For example, the control circuit 42A acquires the voltage applied to the shunt resistor 37u. Then, the control circuit 42A divides the acquired voltage by the resistance value of the shunt resistor 37u. In this way, the control circuit 42A acquires the U-phase current of the drum motor 5.

[0034] The control circuit 42A determines whether or not the U-phase current has been acquired for a first predetermined number of times (e.g., 100 times) or more (step S3). If the control circuit 42A determines that the U-phase current has been acquired for less than the first predetermined number of times (NO in step S3), it returns to the process in step S2. If the control circuit 42A determines that the U-phase current has been acquired for a first predetermined number of times or more (YES in step S3), it determines whether or not the U-phase current for the most recent first predetermined number of U-phase currents is equal to or greater than a predetermined current value for a second predetermined number of times (e.g., 20 times) or less (step S4). The predetermined current value is a current value determined by taking noise into consideration. The second predetermined number of times is a number determined by taking into consideration the first predetermined number of times and the predetermined current value.

[0035] If the control circuit 42A determines that the U-phase current in the most recent first predetermined number of U-phase currents is not above a predetermined current value for the second predetermined number of times (NO in step S4), it returns to the process in step S2. Also, if the control circuit 42A determines that the U-phase current in the most recent first predetermined number of U-phase currents is above a predetermined current value for the second predetermined number of times (YES in step S4), it determines that the drum motor 5 has stopped. If the control circuit 42A determines that the drum motor 5 has stopped, it unlocks the door 3 (step S5).

[0036] Furthermore, the control circuit 42A estimates the rotational speed of the drum motor 5 in parallel from the time the regenerative brake is applied in step S1 until it is determined that the drum motor 5 has stopped. When the control circuit 42A determines that the estimated rotational speed of the drum motor 5 has fallen below a predetermined rotational speed (for example, at point A in Figure 6), it switches the brake from regenerative brake to short-circuit brake and continues the above process. In other words, when the control circuit 42A determines that the estimated rotational speed of the drum motor 5 has fallen below a predetermined rotational speed, it switches IGBTs 35a to 35f from the state where they are switched according to the rotor position to the ON state.

[0037] Next, we will explain the process by which the garment processing machine 100 determines whether to stop the drum motor 5, shown in Figure 4, if it loses step immediately after attempting to stop using the regenerative brake, and the machine uses a short-circuit brake that switches immediately from the regenerative brake. In this example, the door 3 is locked, and the drum motor 5 is stopped by the short-circuit brake, which switches immediately from the regenerative brake, while the drum motor 5 is rotating. The control circuit 42A is able to obtain the rotor angle of the drum motor 5, but it is assumed that the rotor angle cannot be obtained after it loses step. Figure 7 shows an example of the change in the current of the drum motor 5 when the drum motor 5 stops using the short-circuit brake.

[0038] In Figure 7, R_Ia represents the U-phase current of the drum motor 5. Also in Figure 7, as in Figure 6, R_omega_I_32, R_Vdc_L, and S_stage are shown along with R_Ia. The control process shown in Figure 7 includes four stages: rotation, regenerative braking, short-circuit braking, stop determination, and brake termination. The horizontal axis represents time. The vertical axis represents amperes for R_Ia, rpm (Revolutions Per Minute) for R_omega_I_32, and volts for Vdc_L.

[0039] The control circuit 42A applies regenerative braking while the drum motor 5 is rotating (step S11). Assume that the drum motor loses step immediately after the control circuit 42A applies regenerative braking. The control circuit 42A cannot obtain the rotor angle due to the step loss. Therefore, the control circuit 42A determines that the rotational speed of the drum motor 5 is zero. As a result, the control circuit 42A determines that the rotational speed of the drum motor 5 has fallen below a predetermined rotational speed (step S12). Then, the control circuit 42A switches from regenerative braking to short-circuit braking control (step S13). The control circuit 42A obtains the U-phase current of the drum motor 5 at predetermined time intervals (step S14).

[0040] The control circuit 42A determines whether or not the U-phase current has been acquired for a third predetermined number of times (e.g., 300 times) or more (step S15). If the control circuit 42A determines that the U-phase current has been acquired for less than the third predetermined number of times (NO in step S15), it returns to the process in step S14. If the control circuit 42A determines that the U-phase current has been acquired for a third predetermined number of times or more (YES in step S15), it determines whether or not the U-phase current for the most recent third predetermined number of U-phase currents is equal to or greater than a predetermined current value for a fourth predetermined number of times (e.g., 60 times) or less (step S16). The predetermined current value is a current value determined by taking noise into consideration. The fourth predetermined number of times is a number determined by taking into consideration the third predetermined number of times and the predetermined current value.

[0041] If the control circuit 42A determines that the U-phase current for the most recent third predetermined number of U-phase currents is not above a predetermined current value for the fourth predetermined number of times (NO in step S16), it returns to the process in step S14. If the control circuit 42A determines that the U-phase current for the most recent third predetermined number of U-phase currents is above a predetermined current value for the fourth predetermined number of times (YES in step S16), it determines that the drum motor 5 has stopped. Then, after a predetermined time, the control circuit 42A stops the short-circuit brake. Also, if the control circuit 42A determines that the drum motor 5 has stopped, it unlocks the door 3 (step S17).

[0042] Next, we will explain the process by which the garment processing machine 100 determines when the drum motor 5 shown in Figure 5 is stopped by regenerative braking or short-circuit braking, and a malfunction occurs that prevents the brake from being applied due to overvoltage or other reasons, causing the drum motor 5 to stop by free-spinning. In this example, the door 3 is locked, and the drum motor 5 is being stopped by regenerative braking or short-circuit braking from a rotating state, but a malfunction prevents the brake from being applied, causing the drum motor 5 to stop by free-spinning. Figure 8 shows the drum motor 5 stop determination process, which determines that the drum motor 5 has stopped and unlocks the door 3 when the maximum time until the drum motor 5 stops while free-spinning has elapsed. In Figure 8, the horizontal axis is time. The maximum time is determined in advance by experiments or other means when the drum motor 5 is rotated under various washing conditions (when various types of laundry are placed in the drum 7 and operated).

[0043] The control circuit 42A applies the brakes while the drum motor 5 is rotating (step S21). For example, the brakes here are the regenerative brakes described in Figures 3 and 6, and the short-circuit brakes described in Figures 4 and 7. Suppose a malfunction occurs where the brakes cannot be applied between the time the control circuit 42A applies the brakes and the drum motor 5 comes to a stop.

[0044] For example, the control circuit 42A detects the occurrence of a malfunction by detecting an overvoltage (step S22). Then, the control circuit 42A starts measuring the elapsed time (step S23). The control circuit 42A determines whether the measured elapsed time has exceeded the maximum rotation time that has been determined in advance (step S24). If the control circuit 42A determines that the measured elapsed time has not exceeded the maximum rotation time that has been determined in advance (NO in step S24), it returns to the process in step S24. If the control circuit 42A determines that the measured elapsed time has exceeded the maximum rotation time that has been determined in advance (YES in step S24), it determines that the drum motor 5 has stopped. If the control circuit 42A determines that the drum motor 5 has stopped, it unlocks the door 3 (step S25).

[0045] (advantage) The garment processing machine 100 of the embodiment has been described above. In the garment processing machine 100, the control circuit 42A (an example of a control unit) controls the drum motor 5 (an example of a motor) to apply the brake by sensorless driving. The control circuit 42A (an example of an acquisition unit) acquires the current flowing through the drum motor 5 at predetermined time intervals for a first predetermined number of times while the brake is applied. The control circuit 42A (an example of a determination unit) determines that the drum motor 5 is stopped when it determines that the current value of the most recent predetermined number of acquired currents is less than or equal to a predetermined value for a second predetermined number of times. In this way, the garment processing machine 100 can correctly determine when the DC brushless motor is stopped even if the rotation position of the DC brushless motor is unknown.

[0046] <First modified example of the embodiment> In the embodiment described above, the control circuit 42A acquires the voltage applied to the shunt resistor 37u. The control circuit 42A then divides the acquired voltage by the resistance value of the shunt resistor 37u. Thus, the control circuit 42A has been described as acquiring the U-phase current of the drum motor 5. However, in the first modified embodiment, the control circuit 42A may acquire the voltage applied to the shunt resistor 37u via a low-pass filter 60u (Figure 9). The control circuit 42A may then acquire the U-phase current of the drum motor 5 by dividing the acquired voltage by the resistance value of the shunt resistor 37u. Figure 9 shows an example of the low-pass filter 60u in the first modified embodiment. As shown in Figure 9, the low-pass filter 60u is provided between the wiring connecting the emitter of the IGBT 35d and the control circuit 42A. This low-pass filter 60u enables the control circuit 42A to acquire a current value with reduced noise influence. As a result, the control circuit 42A can more accurately determine when the DC brushless motor is stopped compared to when the low-pass filter 60u is not present.

[0047] <Second Modification of Embodiment> In the embodiments described above, the control circuit 42A was described as directly using the U-phase current of the drum motor 5 acquired at predetermined time intervals to determine whether the DC brushless motor 5 is stopped. However, in the second modified embodiment, the control circuit 42A may use the U-phase current of the drum motor 5, obtained using a moving average method, to determine whether the DC brushless motor 5 is stopped. For example, the control circuit 42A identifies the average value of the absolute value of the current for the U-phase current included in a predetermined period, including the most recent current, from among the U-phase currents acquired at predetermined time intervals. The control circuit 42A may then determine that the DC brushless motor 5 has stopped if it determines that the average value of a predetermined number of times is less than or equal to a predetermined number. Figure 10 shows an example of the current value of the U-phase current in the second modified embodiment. The current value P of the U-phase current obtained by moving average shows a change that is almost the same as the value shown by the upper envelope of the original U-phase current, as shown in Figure 10. This control circuit 42A makes it possible to obtain a current value with reduced noise influence. As a result, the control circuit 42A can more accurately determine when the DC brushless motor is stopped compared to when the low-pass filter 60u is not present.

[0048] <Second Modification of Embodiment> In the embodiments described above, the control circuit 42A was described as directly using the U-phase current of the drum motor 5 acquired at predetermined time intervals to determine whether the DC brushless motor 5 is stopped. However, in the second modified embodiment, the control circuit 42A may use the U-phase current of the drum motor 5, obtained using a moving average method, to determine whether the DC brushless motor 5 is stopped. For example, the control circuit 42A identifies the average value of the absolute value of the current for the U-phase current included in a predetermined period, including the most recent current, from among the U-phase currents acquired at predetermined time intervals. The control circuit 42A may then determine that the DC brushless motor 5 has stopped if it determines that the average value of a predetermined number of times is less than or equal to a predetermined number. Figure 10 shows an example of the current value of the U-phase current in the second modified embodiment. The current value P of the U-phase current obtained by moving average shows a change that is almost the same as the value shown by the upper envelope of the original U-phase current, as shown in Figure 10. This control circuit 42A makes it possible to obtain a current value with reduced noise influence. As a result, the control circuit 42A can more accurately determine when the DC brushless motor is stopped compared to when the low-pass filter 60u is not present.

[0049] <Third Modification of the Embodiment> In the embodiments described above, the control circuit 42A was described as determining the stopping of the DC brushless motor 5 using the U-phase current. However, in the third modified embodiment, the control circuit 42A may determine the stopping of the DC brushless motor 5 using the V-phase current or the W-phase current instead of the U-phase current. In other words, the control circuit 42A only needs to determine the stopping of the DC brushless motor 5 using one of the three phase currents of the DC brushless motor 5. In this case, it is necessary to change each processing unit corresponding to the U-phase to each processing unit corresponding to the V-phase current or the W-phase current. For example, when using the V-phase current, a low-pass filter provided between the wiring connecting the emitter of the IGBT35e and the control circuit 42A will be used instead of the low-pass filter 60u described above.

[0050] <Fourth Modification of the Embodiment> In the embodiments described above, the control circuit 42A was described as determining the stopping of the DC brushless motor 5 using one of the three phase currents. However, in the fourth modified embodiment, the control circuit 42A may determine the stopping of the DC brushless motor 5 using the currents of two of the three phase currents. Specifically, the control circuit 42A acquires the currents of two of the three phase currents at predetermined time intervals. The control circuit 42A may then determine that the DC brushless motor 5 has stopped if it determines that the absolute value of the difference between the current values ​​of the two phase currents exceeds a predetermined value in the most recent predetermined number of acquired two phase currents, and this control circuit 42A can correctly determine the stopping of the DC brushless motor by using the difference between multiple current values ​​as described above, even if the two phase currents momentarily coincide due to noise or the like.

[0051] <Fifth Modification of the Embodiment> In the fourth modification of the above-described embodiment, the control circuit 42A was described as using the currents of two of the three phases to determine whether the DC brushless motor 5 is stopped. These currents are obtained from the drum motor 5 and are used directly to determine whether the DC brushless motor 5 is stopped. In the fifth modification of the embodiment, as in the second modification of the embodiment, the stopping of the DC brushless motor 5 may be determined using a moving average of the current values. Specifically, the control circuit 42A identifies the average value of the absolute difference in current values ​​for the two phases of currents included in a predetermined period, including the most recent current, from among the two phases of currents obtained at predetermined time intervals. The control circuit 42A may then determine that the DC brushless motor 5 has stopped if it determines that the predetermined number of average values ​​is less than or equal to a predetermined number. This control circuit 42A allows for a more accurate determination of whether the DC brushless motor is stopped.

[0052] Several embodiments have been described above. However, the embodiments are not limited to the examples described above. Furthermore, some of the embodiments described above can be combined to realize the desired outcome.

[0053] According to at least one embodiment described above, the garment processing machine of the embodiment comprises a control unit, an acquisition unit, and a determination unit. The control unit controls the application of a brake to a sensorless-driven electric motor that does not use a sensor to detect its rotational position. The acquisition unit acquires the current of one of the three phases of current flowing through the electric motor at predetermined time intervals for a predetermined number of times while the brake is applied. The determination unit determines that the electric motor has stopped if it determines that the number of currents exceeding a predetermined value among the most recent predetermined number of currents acquired by the acquisition unit is less than or equal to a predetermined number. With this configuration, it is possible to correctly determine when a DC brushless motor has stopped, even if the rotational position of the DC brushless motor is unknown.

[0054] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims and their equivalents. [Explanation of Symbols]

[0055] 1...Outer casing, 2...Inlet / Outlet, 3...Door, 4...Water receiving tank, 5...Drum motor, 6...Rotating shaft, 7...Drum, 8...Through hole, 9...Baffle, 10...Water supply valve, 11...Water supply valve motor, 12...Water filling case, 13...Water filling port, 14...Drain pipe, 15...Drain valve, 16...Drain valve motor, 17...Main duct, 18...Front duct, 19...Fan casing, 20...Air intake, 21...Exhaust port, 22...Fan motor, 23...Rotating shaft, 24...Fan, 25...Rear duct, 26...Circulation duct, 27...Compressor, 28...Compressor motor, 29...Condenser, 30...Refrigerant pipe, 31 ...heating fins, 34...inverter circuit, 35a~35f...IGBT, 36a~36f...flywheel diode, 37u, 37v, 37w...shunt resistor, 38...inverter circuit, 39...shunt resistor, 40...inverter circuit, 41u, 41v, 41w...shunt resistor, 42A, 42B...control circuit, 43...drive power supply circuit, 44...reactor, 45...full-wave rectifier circuit, 46a, 46b...capacitor, 47...full-wave rectifier circuit, 48...IGBT, 49a, 49b...resistor, 50a, 50b...resistor, 52...current sensor, 100...clothes processing machine.

Claims

1. A control unit that applies the brake to a sensorless-driven electric motor that does not use a sensor to detect its rotational position, An acquisition unit that acquires the current of one of the three phases of current flowing through the motor at predetermined time intervals for a predetermined number of times while the brake is applied, A determination unit determines that the motor has stopped when it determines that among the most recent predetermined number of currents acquired by the acquisition unit, the number of currents exceeding a predetermined value is less than or equal to a predetermined number. A garment processing machine equipped with the following features.

2. The determination unit, The acquisition unit identifies the average absolute value of the currents included in a predetermined period, including the most recent current, from among the currents acquired at predetermined time intervals, and determines that the motor has stopped if it is determined that the predetermined number of such average values ​​is less than or equal to the predetermined number. The garment processing machine according to claim 1.

3. A low-pass filter is placed between the electric motor and the acquisition unit. Equipped with, The acquisition unit is, The current flowing through the electric motor is obtained as the current that has passed through the low-pass filter. The garment processing machine according to claim 1.

4. The determination unit, If a malfunction occurs while the control unit is applying the brakes, and the motor becomes idle, the control unit determines that the motor has stopped after a predetermined time has elapsed since the motor was determined to be idle. The garment processing machine according to claim 1.

5. The acquisition unit is, The currents of two of the three phases are acquired at predetermined time intervals. The determination unit, The acquisition unit determines that the motor has stopped if, among the most recent predetermined number of two-phase currents acquired by the acquisition unit, the absolute value of the difference between the current values ​​of the two-phase currents exceeds a predetermined value, and the number of such two-phase currents is less than or equal to a predetermined value. The garment processing machine according to claim 1.

6. The determination unit, The acquisition unit identifies the average value of the absolute difference in current values ​​for the two phase currents included in a predetermined period, including the most recent current, from among the two phase currents acquired at predetermined time intervals, and determines that the motor has stopped if it is determined that the predetermined number of such average values ​​is less than or equal to the predetermined number. The garment processing machine according to claim 5.

7. Between the electric motor and the acquisition unit, there are two low-pass filters. Equipped with, The acquisition unit is, The two phases of current flowing through the motor are obtained as the current that has passed through one of the two low-pass filters and the current that has passed through the other of the two low-pass filters. The garment processing machine according to claim 5.

8. The control unit, If the rotational speed of the motor exceeds a predetermined rotational speed, control is performed to apply regenerative braking to the motor; if it is determined that the rotational speed of the motor is below the predetermined rotational speed, control is performed to apply short-circuit braking to the motor. The garment processing machine according to claim 1.

9. This involves controlling a sensorless motor that does not use a sensor to detect its rotational position, by applying a brake to it. While the brake is applied, the current of one of the three phases of current flowing through the motor is acquired at predetermined time intervals for a predetermined number of times or more. The motor is determined to have stopped if it is determined that the number of currents exceeding a predetermined value among the most recent predetermined number of currents obtained is less than or equal to a predetermined number. A processing method that includes this.

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