JP2006288927A - Motor controller of washing machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a washing machine which prevents the inertia rotation of a three-phase DC brushless motor and the rise of a DC power supply voltage for driving the three-phase DC brushless motor when power supply from an AC power source is stopped during the rotation of the three-phase DC brushless motor, in an inverter motor washing machine. <P>SOLUTION: When the power supply is stopped during the rotation of the three-phase DC brushless motor 4, the DC power supply voltage of a capacitor 3 for driving the three-phase DC brushless motor 4 is monitored by a voltage monitoring device 10. When the voltage is lower than a prescribed value, the three-phase DC brushless motor 4 is made to perform the inertia rotation by the control circuit 9 of an inverter unit 5, and thus power is regenerated from the three-phase DC brushless motor 4 to a DC power source. When the DC power supply voltage is higher than the prescribed value, the three phases of the three-phase DC brushless motor 4 are short-circuited, braking is performed, the inertia rotation time of the three-phase DC brushless motor 4 is reduced by the repetition, and the excessive rise of the DC power supply voltage of the capacitor 3 is prevented. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a motor control device for a washing machine having a three-phase DC brushless motor.

  In a washing machine using a three-phase DC brushless motor, if the power supply from the AC power supply stops during dehydration, the control circuit of the three-phase DC brushless motor becomes inoperable and the three-phase DC brushless motor loses control. It will continue inertial rotation. At this time, since the motor inverter circuit has a regenerative diode, power regeneration occurs in the DC power source that drives the three-phase DC brushless motor due to the regenerative diode, and a phenomenon such as an abnormally high DC power supply voltage may occur. there were. That is, there is a problem that the three-phase DC brushless motor continues inertial rotation without control or the DC power supply voltage rises.

On the other hand, conventionally, when power supply to the DC power supply is stopped, the following control is performed. In other words, there is a circuit that detects the presence of an AC power supply separately from the inverter device, and the motor control circuit is such that the drive control of the three-phase DC brushless motor is performed by the rotation control device at the time of power supply. When the power supply to the motor is stopped, the command signal from the rotation control device is interrupted, and at that time, the rotation of the three-phase DC brushless motor is braked by another braking device that operates with the charging voltage of the capacitor constituting the DC power supply ( For example, see Patent Document 1).
JP-A-9-163786

  However, in the above-described conventional configuration, in order to brake the three-phase DC brushless motor when the power supply to the DC power source for driving the motor is interrupted, another new device for braking the three-phase DC brushless motor is added. Had the task of having to do.

  The present invention solves the above-described conventional problems, and prevents the rotation of the three-phase DC brushless motor from becoming uncontrolled when the power supply to the DC power supply is interrupted while the three-phase DC brushless motor is rotating. DC power generated by the regenerative power of the three-phase DC brushless motor, such as capacitor, regenerative device, motor drive circuit, etc. It is possible to reduce the component rating related to the voltage, and it is possible to reduce the size and price, and to eliminate the need for regenerative power absorption, thus reducing the number of components. The purpose is that.

  In order to solve the conventional problems, a motor control device for a washing machine according to the present invention includes a three-phase DC brushless motor, a first DC power supply for supplying power to the three-phase DC brushless motor, and the first A second DC power source obtained from the DC power source, a voltage monitoring device for monitoring the voltage of the first DC power source, and power generated by the three-phase DC brushless motor during inertial rotation are supplied to the first DC power source. A regenerator, a three-phase short-circuit device that simultaneously short-circuits the three phases of the three-phase DC brushless motor, and the three-phase short-circuit device that operates using the second DC power supply and receives an output from the voltage monitoring device. And a control circuit for controlling the switching of the regenerative device, the control circuit when the power is not supplied to the first DC power supply during rotation of the three-phase DC brushless motor, DC The first voltage set to a value that is higher than the voltage of the first DC power source, and the voltage of the first DC power source is lower than the maximum voltage rating of the component to which the voltage of the first DC power source is applied. When the voltage is higher, the three phases of the three-phase DC brushless motor are short-circuited. When the voltage of the first DC power supply is lower than the first voltage, the power generated by the rotation of the three-phase DC brushless motor is regenerated. The control to be executed is executed.

  As a result, even when the power supply to the DC power supply is interrupted during the rotation of the three-phase DC brushless motor, the rotation of the three-phase DC brushless motor is prevented from becoming uncontrolled, and the rotation is stopped quickly. While ensuring safety, it is possible to reduce the component rating related to the DC power supply voltage generated by the regenerative power of the motor, such as the rating of components such as capacitors, regenerative devices, drive circuits, etc. used for DC power supply, making it compact Therefore, it is possible to reduce the number of parts because it is possible to reduce the price and to eliminate the need for parts for absorbing regenerative power.

  The motor control device for a washing machine according to the present invention prevents the rotation of the three-phase DC brushless motor from being uncontrolled when the power supply to the DC power supply is interrupted while the three-phase DC brushless motor is rotating. In addition to ensuring the safety by stopping the rotation, it is related to the DC power supply voltage generated by the regenerative power of the three-phase DC brushless motor, such as the capacitor rating, the regenerative device, the drive circuit, etc. used in the DC power supply The component rating can be reduced, the size can be reduced and the price can be reduced, and a component for absorbing regenerative power is not necessary, so that the number of components can be reduced.

  A motor control device for a washing machine according to a first aspect of the present invention is a three-phase DC brushless motor, a first DC power source for supplying power to the three-phase DC brushless motor, and a second DC power source obtained from the first DC power source. A DC power supply, a voltage monitoring device that monitors the voltage of the first DC power supply, a regenerative device that supplies power generated by the three-phase DC brushless motor during inertial rotation to the first DC power supply, and the three-phase DC A three-phase short-circuit device that simultaneously short-circuits the three phases of the brushless motor, and a control that switches between the three-phase short-circuit device and the regenerative device that operates using the second DC power supply and receives an output from the voltage monitoring device. A control circuit that controls the voltage of the first DC power supply when the power is not supplied to the first DC power supply during rotation of the three-phase DC brushless motor. Move When the voltage of the first DC power supply becomes higher and the voltage of the first DC power supply is higher than the first voltage set to a value lower than the maximum voltage rating of the component to which the voltage is applied, the three-phase DC brushless By performing a control to regenerate the power generated by the rotation of the three-phase DC brushless motor when the three phases of the motor are short-circuited and the voltage of the first DC power supply is lower than the first voltage, 3 When power supply to the DC power supply is interrupted while the phase DC brushless motor is rotating, the DC power supply voltage is prevented from excessively rising due to regenerative power, preventing rotation of the three-phase DC brushless motor from being uncontrolled. In addition to ensuring safety by quickly stopping the rotation, three-phase DC brushless, such as capacitors used in DC power supplies, regenerative devices, drive circuits, etc. The component rating related to the DC power supply voltage generated by the regenerative power of the motor can be reduced, the size can be reduced and the price can be reduced, and the component for absorbing regenerative power is not required. Reduction of points can be realized.

  The motor control device for a washing machine according to a second invention is the motor control device for a washing machine according to the first invention, wherein the first voltage is set to the lowest voltage of the first DC power supply capable of operating the control circuit. By doing so, the brake operation can be performed up to the low rotation range of the three-phase DC brushless motor where the regenerative power of the three-phase DC brushless motor is reduced. Intermittent braking operation can be performed, and rotation stop can be realized more quickly than in the first invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a circuit diagram of a motor control device according to a first embodiment of the present invention. In FIG. 1, DC rectification smoothing is performed by a rectifier diode 2 and a capacitor 3 from an AC power source 1, and the capacitor 3 forms a first DC power source. The three-phase DC brushless motor 4 is driven and controlled by an inverter device 5. The inverter device 5 includes a regeneration device 6, a switching element 7, an inverter circuit 8 including the regeneration device 6 and the switching element 7, and a control circuit 9.

  The regenerative device 6 is configured as follows. That is, the anodes of the diodes 6d, 6e, and 6f are connected to the negative terminal of the capacitor 3, the anodes of the diodes 6a, 6b, and 6c are connected to the cathodes of the respective diodes, and the cathodes are connected to the positive terminal of the capacitor 3. is doing. A connection point between the diode 6a and the diode 6d, a connection point between the diode 6b and the diode 6e, and a connection point between the diode 6c and the diode 6f are connected to the three-phase terminals of the three-phase DC brushless motor 4, respectively.

  Moreover, the switching element 7 is comprised by IGBT. As for the connection, the collectors of the IGBTs 7a, 7b and 7c are connected to the positive terminal of the capacitor 3, the emitter of the IGBT 7a is connected to the anode of the diode 6a and the collector of the IGBT 7d, and the emitter of the IGBT 7b is the anode of the diode 6b and the collector of the IGBT 7e. The emitter of the IGBT 7c is connected to the anode of the diode 6c and the collector of the IGBT 7f, and the emitters of the IGBTs 7d, 7e, and 7f are connected to the negative terminal of the capacitor 3.

  In addition, each line of the motor connected to the anodes of the diodes 6a, 6b, and 6c has a U phase, a V phase, and a W phase, respectively.

  As described above, the inverter circuit 8 includes the regenerative device 6 and the switching element 7, and becomes a three-phase short circuit device by the control circuit 9. In the three-phase short circuit device, for example, by turning on the gates of the IGBTs 7d, 7e, and 7f by the control circuit 9, it is possible to dissipate the power during inertial rotation within the three phases by these IGBTs and the diodes constituting the regenerative device 6. . The output of the control circuit 9 is connected to the gates of the IGBTs 7a to 7f, and controls the rotation and stop of the motor 4.

  The voltage monitoring device 10 divides the DC voltage of the capacitor 3 with a resistor and sends the voltage information to the control circuit 9. Although not shown in the present embodiment, it is naturally conceivable to remove a ripple voltage by connecting a capacitor in parallel with the lower resistor in order to stabilize the divided voltage. The voltage is divided so that it can be used by the control circuit 9 that operates with the second DC power supply, and the voltage is made equal to or lower than the voltage of the second DC power supply, and the output is sent to the control circuit 9.

  The control circuit 9 recognizes the level based on the information from the voltage monitoring device 10 and controls the operation of the inverter circuit 8 according to the level. The voltage monitoring device 10 connects a resistor in series between both terminals of the capacitor 3 and outputs voltage information to the control circuit 9 from the connection point of the resistor.

  The second DC power supply 11 obtains input power from both terminals of the capacitor 3 and supplies DC power to the control circuit 9. Since the control circuit 9 is operated by this power supply, the output voltage of the second DC power supply causes the control circuit 9 to operate when the voltage of the first DC power supply constituted by the capacitor 3 decreases by a certain value or more. Is impossible.

  In order to detect that the power supply to the first DC power source constituted by the capacitor 3 is interrupted, a method for detecting that the first DC power source voltage constituted by the capacitor 3 has dropped by a certain value or more. In the case where the first DC power source constituted by the capacitor 3 is created from the AC power source, a method for detecting a DC smoothing voltage when the voltage fluctuates beyond the allowable voltage range that serves as a commercial AC power source, AC A circuit for detecting a power supply voltage (for example, when a pulse is generated when the AC power supply voltage is close to 0 V by another circuit and the pulse disappears, it is detected that the power supply to the DC power supply is interrupted) Various methods are conceivable, such as a method of sending the AC voltage to the control circuit 9 when it becomes impossible to detect the AC voltage due to the above, but the present invention aims at the detection method. Instead of a how to the purpose of controlling when the power supply was interrupted, therefore, for these in the present embodiment, it is assumed not to mention.

  In the present embodiment, the three-phase short circuit device and the regenerative device 6 are configured by an inverter circuit 8. That is, in the present embodiment, the regenerative device 6 and the three-phase short circuit device are obtained by extracting elements necessary for the present embodiment, and these elements are separately mounted or used as part of the inverter device. Is optional.

  The operation of the above configuration will be described with reference to FIG. FIG. 2 is a time chart of the first DC power supply voltage of the motor control device according to the first embodiment of the present invention.

  In FIG. 2, when the three-phase DC brushless motor 4 is rotating, such as during dehydration, the first DC power supply voltage constituted by the capacitor 3 is the same as that of a when power is supplied from the AC power supply 1. It is a DC power supply voltage.

  Next, when the power supply from the AC power supply is interrupted, the three-phase DC brushless motor 4 and other circuits (the voltage monitoring device 10 etc. consumes the power of the first DC power supply constituted by the capacitor 3. In addition, although not shown in the present embodiment, it is normal that other circuits are also connected, thereby consuming electric power from the first DC power source constituted by the capacitor 3) Therefore, the voltage drops as shown in b. When the voltage drops and falls below the first voltage, the control circuit 9 receives the output from the voltage monitoring device 10, stops the motor drive control so far, and stops all three-phase driving. That is, in the switching element 7, the output from the control circuit 9 becomes 0 and no voltage is applied to the gate of the IGBT. As a result, the IGBT is turned off, and the three-phase DC brushless motor 4 is coasting.

  When the three-phase DC brushless motor 4 is inertially rotated, power is regenerated to the first DC power source constituted by the capacitor 3 through the regenerative device 6. For example, when the U phase of the generated voltage of the three-phase DC brushless motor 4 is the maximum voltage and the V phase is the minimum voltage, the U phase, the diode 6a, the positive terminal of the capacitor 3, the negative terminal of the capacitor 3, the diode 6e, V-phase and current flow, and power is regenerated in the capacitor 3. Depending on the time, a current flows from the phase generating the maximum voltage to the phase generating the minimum voltage, and power is regenerated.

  As a result, as soon as the voltage rises, the first voltage is exceeded, so that the control circuit 9 turns on the gates of the IGBTs 7d, 7e, and 7f by the information from the voltage monitoring device 10 to turn on these IGBTs. , 7c are turned off to turn off these IGBTs.

  At this time, the three-phase DC brushless motor 4 generates a voltage generated by the three-phase DC brushless motor 4 in each phase due to its rotation. For example, if the V and W phases generate higher voltages than the U phase, the generated voltage from the three-phase DC brushless motor 4 changes from the V phase to the U phase via the collector of the IGBT 7e and the emitter via the diode 6d. Current flows, current flows from the collector of the IGBT 7f through the diode 6d from the W phase, and the three-phase DC brushless motor 4 and these paths constitute a closed loop, and the generated power of the three-phase DC brushless motor 4 is Is consumed. Thus, the three-phase short-circuit state is generated. The current flows from the higher voltage of the motor line to the lower voltage, and the generated power is consumed.

  At the same time, braking acts on the three-phase DC brushless motor 4 and the rotation decreases. During this time, the capacitor 3 as the first DC power source consumes power by the second DC power source 11, the voltage monitoring device 10 and other circuits, and the voltage of the first DC power source constituted by the capacitor 3 decreases.

  As soon as the voltage of the first DC power source constituted by the capacitor 3 decreases, the three phases of the IGBT are immediately opened again to regenerate power from the three-phase DC brushless motor 4 to the capacitor 3. Thereafter, such an operation is repeated. As described above, the voltage of the first DC power source constituted by the capacitor 3 rises and falls with the first voltage as a boundary. The voltage of the first DC power source constituted by the capacitor 3 is as indicated by c in FIG. It becomes almost the first voltage.

  In this way, regeneration and three-phase short-circuit are alternately repeated, but since the brake is applied when the three-phase short-circuit occurs, the rotation of the three-phase DC brushless motor 4 decreases. When the regenerative voltage due to the regenerative power corresponding to the rotation speed of the three-phase DC brushless motor 4 falls below the first voltage, the capacitor voltage falls from the first voltage as shown by the portion e from the point d in FIG. Will be followed.

  As described above, when the power supply to the DC power supply is interrupted while the three-phase DC brushless motor is rotating, the motor control device for the washing machine according to the first embodiment causes excessive DC power supply voltage due to regenerative power. Prevents the rise, prevents the rotation of the three-phase DC brushless motor from becoming uncontrolled, and quickly stops the rotation to ensure safety, as well as the capacitor, regenerative device, and drive used for the DC power supply It is possible to reduce the component rating related to the DC power supply voltage generated by the regenerative power of the three-phase DC brushless motor, such as the rating of the circuit, parts, etc., making it possible to reduce the size and price, and to absorb the regenerative power Therefore, the number of parts can be reduced.

(Embodiment 2)
In the second embodiment, the first voltage in the first embodiment is set to a value close to the voltage of the first DC power supply at which the control circuit becomes inoperable. This is the same as in the first embodiment. Other configurations are the same as those in the first embodiment, and a description thereof will be omitted.

  The DC power supply voltage of the capacitor 3 due to regeneration of the three-phase DC brushless motor 4 becomes lower as the rotational speed decreases. Therefore, when the first voltage is set to a low value, it becomes possible to perform a braking operation until the three-phase DC brushless motor 4 is almost stopped, and the time for rotating by inertial rotation is shortened. It is possible to further shorten the time until the stop.

  As described above, the motor control device of the washing machine according to the present invention is inertial when the power supply to the washing machine is interrupted due to a power failure or the like while the dewatering tub is rotating at high rotation such as dehydration of the washing machine. By preventing the generation of excessive DC power supply voltage by continuing rotation, it becomes possible to realize a cheap and safe washing machine employing an inverter motor, and in a washing machine employing an inverter motor, Since the uncontrolled state of rotation can be eliminated and the motor can be stopped quickly, it is useful as a motor control device such as a washing machine employing an inverter motor.

The circuit diagram of the motor control apparatus of the washing machine in the 1st embodiment of the present invention Time chart of first DC power supply voltage of motor control device of same washing machine

Explanation of symbols

1 AC power supply 2 Rectifier diode 3 Capacitor (first DC power supply)
4 Three-phase DC brushless motor 5 Inverter device 6 Regenerative device 7 Switching element 8 Inverter circuit 9 Control circuit 10 Voltage monitoring device 11 Second DC power supply

Claims (2)

A three-phase DC brushless motor, a first DC power supply for supplying power to the three-phase DC brushless motor, a second DC power supply obtained from the first DC power supply, and a voltage of the first DC power supply Voltage monitoring device for monitoring, regenerative device for supplying power generated by the three-phase DC brushless motor during inertial rotation to the first DC power supply, and three-phase short-circuit device for simultaneously short-circuiting the three phases of the three-phase DC brushless motor And a control circuit that operates using the second DC power supply and receives the output from the voltage monitoring device and performs control to switch between the three-phase short-circuit device and the regenerative device, When power is not supplied to the first DC power supply during rotation of the three-phase DC brushless motor, the voltage of the first DC power supply becomes such that the voltage of the first DC power supply cannot operate the control circuit. And when the voltage of the first DC power supply is higher than the first voltage set to a value lower than the maximum voltage rating of the component to which the voltage is applied, the three phases of the three-phase DC brushless motor are short-circuited, A motor control device for a washing machine that executes control for regenerating electric power generated by the rotation of the three-phase DC brushless motor when the voltage of one DC power supply is lower than the first voltage. The motor control device for a washing machine according to claim 1, wherein the first voltage is set to a minimum voltage of a first DC power supply capable of operating the control circuit.