KR20200113873A - motor driving device including a single inverter for a one phase motor and a three phases motor and an applicance having the same - Google Patents

Abstract

The present invention relates to a driving device for driving a plurality of motors, particularly three-phase and one-phase motors using a single inverter, and a home appliance including the same. According to an embodiment of the present invention, in the device for driving the motor in which an upper switching element and a lower switching element constitute a pair of switching units, and the three-phase motor and the one-phase motor are provided to be controlled in a parallel operation through the inverter having a total of three pairs of switching units and a connection point (neutral end) of upper and lower divided direct current (DC)-link capacitors, two pairs of switching units (three-phase switching units) are provided to be connected to a-phase and b-phase terminals of the three-phase motor, and the other pair of switching units (one-phase switching unit) is provided to be connected to a first terminal of the one-phase motor. The neutral end is provided to be connected to a c-phase terminal of the three-phase motor and a second terminal of the one-phase motor.

Description

[Motor driving device including a single inverter for a one phase motor and a three phases motor and an applicance having the same}

The present invention relates to a driving device for driving a plurality of motors, in particular three-phase and one-phase motors using a single inverter, and a home appliance including the same.

The motor refers to a device in which the rotor rotates with respect to the stator, and the motor driving device (driver) may be referred to as a device for controlling the driving of the motor.

A coil is wound around the stator, and the direction of the magnetic field is changed by applying an alternating current, and the rotor rotates with respect to the stator according to the change in the magnetic field. The motor driving device is a device for controlling the driving of such a motor, and may be provided to control the rotation speed, rotation direction and torque of the rotor.

When a motor and a motor driving device are applied to a home appliance, the processor (control unit) of the home appliance controls the motor driving device to control driving of the motor.

The motor driving apparatus may broadly include an inverter, an inverter control unit, an output current detection unit that detects an output current flowing through the motor, and an output voltage detection unit that detects an output voltage applied to the motor. The motor driving device may narrowly mean an inverter or an inverter circuit.

In general, in order to drive a three-phase motor, a three-phase motor driver or inverter circuit (B6 inverter) using six switching elements is applied. For the purpose of reducing material cost, a B4 inverter topology using a connection point of four switching elements and a neutral terminal, that is, a split DC-Link capacitor has been proposed. That is, it can be said that a pair of switching elements for switching the current of a specific phase is omitted, and a node between the capacitors at both ends of a specific phase is connected to a specific phase of a three-phase motor.

However, in this case, a difference between the command voltage and the actual generated voltage occurs due to the difference in the DC link voltage applied from both ends of the upper and lower capacitors. Due to this asymmetrical output voltage characteristic, torque ripple in the motor becomes large, and a reduction in voltage utilization inevitably occurs. Therefore, it can be said that the main task in the B4 inverter is to improve the distortion of the output voltage and the increased unbalance characteristics compared to the B6 inverter.

Korean Patent Publication 10-2017-0087271 (hereinafter referred to as "prior patent") proposes a motor driving device for controlling a three-phase motor and a one-phase motor using a single inverter, and a home appliance including the same.

However, the prior patent does not specifically disclose a method of parallel operation of a three-phase motor and a one-phase motor. That is, when a three-phase motor and a one-phase motor are controlled using a single inverter, the motor control method for the number of possible occurrences is not clearly presented. In other words, when only a 1-phase motor or 3-phase motor is driven, when two motors are running at the same time, and when the other motor is running when one motor is started, a clear control method is initiated. Not doing.

The voltage vector application period (180 degrees) of the 1-phase motor and the voltage vector application period (90 degrees) of the 3-phase motor are different from each other. In the prior patent, a specific compensation scheme for voltage deviation is not disclosed in a parallel operation method of motors having different voltage vector application periods.

On the other hand, the 1-phase motor has a position where the starting torque becomes 0 (zero) according to the starting torque position due to its characteristics. That is, in a 1-phase motor, when the rotor is in a specific position, there is a problem that it is impossible to start.

Of course, it is possible to solve the starting problem by changing the structure of the 1-phase motor. However, this structural change is possible only for one-way start, and it is difficult to manufacture and optimize the motor. In addition, a structure for connecting a starting capacitor between the main winding and the auxiliary winding may be used. In this structure, a fixed frequency method in which a fixed frequency power is applied in a line-start method and a method in which a variable frequency is applied using an inverter can be applied. However, the fixed frequency method has a problem that only one-way start is possible, and the variable frequency method has a problem that starting is impossible or not smooth due to a lack of starting torque at a specific position.

Therefore, when driving and controlling a 1-phase motor and a 3-phase motor using a single inverter, the output voltage imbalance can be minimized, and the 1-phase motor can be aligned to smoothly start in both directions, and the 3-phase motor is aligned and started. It is necessary to find a way to maximize the characteristics.

The present invention basically aims to solve the above-described conventional problem.

According to an embodiment of the present invention, an object is to provide a motor driving apparatus and a control method thereof capable of effectively performing parallel operation of a 1-phase motor and a 3-phase motor through a single inverter.

Through an embodiment of the present invention, it is intended to provide a motor alignment method capable of eliminating the inability to start a 1-phase motor and maximizing the starting torque.

An object of the present invention is to provide a motor alignment method capable of maximizing starting torque in a three-phase motor.

According to an embodiment of the present invention, a motor driving apparatus capable of stably driving a 1-phase motor and a 3-phase motor by eliminating voltage imbalance and a control method thereof is provided.

In order to achieve the above object, according to an embodiment of the present invention, it is possible to provide a motor driving apparatus capable of driving a 1-phase motor and a 3-phase motor in parallel, and a control method thereof. It is possible to provide a home appliance to which such a 1-phase motor, a 3-phase motor, and a motor driving device is applied, and a control method thereof.

A typical example of such a home appliance is a washing machine, and the motor driving device according to the present embodiment may be applied to a home appliance such as a refrigerator and an air conditioner in which a plurality of motors can be used.

Specifically, in the motor driving device, the upper switching element and the lower switching element constitute a pair of switching units, and a three-phase motor and a three-phase motor through an inverter having a connection point (neutral end) of a total of three pairs of switching units and a vertically divided DC-link capacitor. It may be provided to control the parallel operation of the 1-phase motor.

In the motor driving apparatus, two pairs of switching units (three-phase switching units) are provided to be connected to a phase a terminal and a phase b terminal of a three-phase motor, respectively, and the other pair of switching units (one-phase switching unit) is a one-phase It is provided to be connected to the first terminal of the motor, and the neutral end may be provided to be connected to the c-phase terminal of the 3-phase motor and the second terminal of the 1-phase motor.

It is preferable that the upper switching element Sc and the lower switching element Sc_bar of the one-phase switching unit operate complementarily to prevent an arm short so that simultaneous ON is not possible.

It is preferable that the operation of the upper switching element Sc and the lower switching element Sc_bar is performed in consideration of a dead time and an idle time, which are inherent characteristics of the element.

It is preferable that the maximum time when the upper switching element Sc and the lower switching element Sc_bar are operated is set to be smaller than the sum of the dead time and the idle time and controlled.

When the driving command of the 1-phase motor is reached to the motor driving device, the motor driving device performs alignment so that the rotor of the 1-phase motor avoids a position incapable of starting, and then controls the 1-phase motor to be driven. It is desirable.

It is preferable that the motor driving device injects a stirring current to the 1-phase motor through driving of the upper switching element Sc and the lower switching element Sc_bar, and controls the rotor to avoid a position in which it cannot be started.

It is preferable that the motor driving device is controlled by differently setting a ratio of the on time (T1) of the upper switching element (Sc) and the off time (T2) of the lower switching element (Sc_bar). .

The motor driving device is configured to generate the first phase by turning on the current and torque applied to the one-phase motor by turning on the upper switching element Sc and turning on the lower switching element Sc. It is preferable to control the rotor so as to avoid the position where it cannot start by varying the values of the current and torque applied to the motor.

Current and torque applied to the 1-phase motor may be performed based on a PWM signal.

The waveform of the PWM signal may be any one of a sine waveform, a square waveform, or a trapezoidal waveform.

When the driving command of the 1-phase motor is reached to the motor driving device, it is preferable that the motor driving device change the driving method of the 1-phase motor according to whether or not the 3-phase motor is currently driven. Through this, it is possible to more effectively align the 1-phase motor and reduce voltage imbalance.

When the three-phase motor is driven, the motor driving device is agitated to generate a forward/reverse rotation torque to the one-phase motor through driving of the upper switching element Sc and the lower switching element Sc_bar. It is desirable to control to inject current.

The motor driving device is a section in which only the upper DC link voltage (V1) is applied to the three-phase motor through the two pairs of switching units (Sa, Sa_bar, Sb, Sb_bar) and only the lower DC link voltage (V2) is applied. In the section, it is preferable to control the stirring current to be injected into the 1-phase motor.

The motor driving device outputs a positive current by driving the upper switching element Sc to On in a section in which only the voltage V2 is applied to the three-phase motor, and in a section in which only V1 voltage is applied to the three-phase motor. It is preferable to reduce the voltage imbalance applied to the three-phase motor by driving the lower switching element Sc_bar to ON to output a negative current.

When a driving command of the three-phase motor is reached to the motor driving device, it is preferable that the motor driving device change the driving method of the three-phase motor according to whether or not the one-phase motor is currently driven. Through this, it is possible to more effectively align the three-phase motor and reduce voltage imbalance.

The motor drive device, when the one-phase motor is stopped, the upper DC link voltage (V1) and the lower DC link voltage to the three-phase motor through the two pairs of switching units (Sa, Sa_bar, Sb, Sb_bar) In a section in which all (V2) is applied, it is preferable to perform alignment of the three-phase motor in a section in which both voltages V2 and V1 are applied to the three-phase motor.

The motor driving device aligns the three-phase motor by applying only the voltage V2 to the three-phase motor in a section in which only the voltage V1 is applied to the one-phase motor when the one-phase motor is being driven, and the one-phase motor In a section in which only the voltage V2 is applied to the motor, it is preferable to align the three-phase motor by applying only the voltage V1 to the three-phase motor.

When the driving command of the 1-phase motor and the driving command of the 3-phase motor reach the motor driving device at the same time, the motor driving device first drives one of the 1-phase motor and the 3-phase motor, and then drives the other. Can be controlled to do. Through this, voltage imbalance can be resolved and a simpler control logic can be constructed.

In a state in which both the 1-phase motor and the 3-phase motor are stopped, the motor driving device may control the other motor to be driven after a predetermined time after one motor is driven.

In order to reduce the output voltage imbalance in the three-phase motor, the motor driving device is provided in a state in which both the one-phase motor and the three-phase motor are driven and the speeds of the one-phase motor and the three-phase motor are the same. , It is preferable to control the maximum voltage output position of the 1-phase motor and the maximum voltage output position of the 3-phase motor differently from each other.

In order to reduce the output voltage imbalance in the three-phase motor, the motor driving device is provided under a condition in which speeds of the one-phase motor and the three-phase motor are different in a state in which both the one-phase motor and the three-phase motor are driven. , It is preferable to control the ratio of the section in which only the upper DC link voltage V1 applied to the 1-phase motor is applied and the section in which only the lower DC link voltage V2 is applied is different.

When V2 is greater than V1, the motor driving device controls driving of the 1-phase switching unit so that a section in which only V1 is applied is reduced and a section in which only V2 is applied is increased within one cycle, and the V1 When V2 is smaller than that, it is preferable to control the driving of the 1-phase switching unit so that the section in which only V1 is applied is increased and the section in which only V2 is applied is decreased within one cycle.

It is preferable that the motor driving apparatus performs proportional reduction and increase of the section as the cycle progresses.

It is preferable that the motor driving device is controlled so that the duty ratio of the three-phase switching unit remains the same even when the V1 and V2 are different from each other.

In order to achieve the above object, according to an embodiment of the present invention, it is possible to provide a motor driving apparatus capable of driving a 1-phase motor and a 3-phase motor in parallel, and a control method thereof. It is possible to provide a home appliance to which such a 1-phase motor, a 3-phase motor, and a motor driving device is applied, and a control method thereof.

A typical example of such a home appliance is a washing machine, and the motor driving device according to the present embodiment may be applied to a home appliance such as a refrigerator and an air conditioner in which a plurality of motors can be used.

Specifically, the motor driving device is a three-phase motor through an inverter having a total of three pairs of switching units and a connection point (neutral end) between the upper and lower switching elements formed by a pair of switching units. And a one-phase motor may be provided to control parallel operation.

In the motor driving apparatus, two pairs of switching units (three-phase switching units) are provided to be connected to a phase a terminal and a phase b terminal of a three-phase motor, respectively, and the neutral terminal is connected to a phase c terminal of the three-phase motor. Thus, it may be provided to control the driving of the three-phase motor by the three-phase switching unit.

In the motor driving apparatus, another pair of switching units (1-phase switching units) are connected to a first terminal of the 1-phase motor, and a second terminal of the 1-phase motor is connected to the neutral terminal, and the 1-phase switching unit It may be provided to control the driving of the 1-phase motor by.

The motor driving device may be provided to control the 1-phase motor and the 3-phase motor to interlock and drive in parallel through the 1-phase switching unit and the 3-phase switching unit when the 1-phase motor and the 3-phase motor are simultaneously driven. .

The motor driving device may be provided to control the other motor to be driven after a predetermined time after one motor is driven in a state in which both the 1-phase motor and the 3-phase motor are stopped.

When the driving command of the 1-phase motor and the driving command of the 3-phase motor reach the motor driving device at the same time, the motor driving device first drives one of the 1-phase motor and the 3-phase motor, and then drives the other. Can be controlled to do.

In order to reduce the output voltage imbalance in the three-phase motor, the motor driving device is provided in a state in which both the one-phase motor and the three-phase motor are driven and the speeds of the one-phase motor and the three-phase motor are the same. It is preferable to control the parallel operation of the one-phase motor and the three-phase motor differently from the case.

It is preferable that the motor driving device outputs the voltage of the 1-phase motor by interlocking or synchronizing with electric angle reference position information of the 3-phase motor.

The motor driving device may maintain a driving condition of the three-phase switching unit and may change a driving condition of the one-phase switching unit.

The motor driving device may control to output the voltage of the 1-phase motor by interlocking or synchronizing with the electric angle reference position information of the 3-phase motor.

The motor driving device may differently control a maximum voltage output position of the 1-phase motor and a maximum voltage output position of the 3-phase motor when the speeds of the 1-phase motor and the 3-phase motor are the same.

When the speed of the 1-phase motor and 3-phase motor are different, the motor driving device applies only the upper DC link voltage V1 applied to the 1-phase motor and only the lower DC link voltage V2. It can be controlled so that the ratio of the section becomes different.

When V2 is greater than V1, the motor driving device controls driving of the 1-phase switching unit so that a section in which only V1 is applied is reduced and a section in which only V2 is applied is increased within one cycle, and the V1 When V2 is smaller than that, it is preferable to control the driving of the 1-phase switching unit so that the section in which only V1 is applied is increased and the section in which only V2 is applied is decreased within one cycle.

It is preferable that the motor driving apparatus performs proportional reduction and increase of the section as the cycle progresses.

It is preferable that the motor driving device is controlled so that the duty ratio of the three-phase switching unit remains the same even when the V1 and V2 are different from each other.

When the driving command of the 1-phase motor is reached to the motor driving device, the motor driving device performs alignment so that the rotor of the 1-phase motor avoids a position incapable of starting, and then controls the 1-phase motor to be driven. It is desirable.

The motor driving device controls the rotor to avoid a start impossible position by injecting a stirring current to the one-phase motor through driving of the upper switching element Sc and the lower switching element Sc_bar of the one-phase switching unit. It is desirable.

It is preferable that the motor driving device is controlled by differently setting a ratio of the on time T1 of the upper switching element Sc and the off time T2 of the lower switching element Sc_bar. .

The motor driving device includes values of current and torque applied to the 1-phase motor by turning on the upper switching element Sc of the 1-phase switching unit, and turning on the lower switching element Sc of the 1-phase switching unit. By varying the values of the current and torque applied to the 1-phase motor by (On), the rotor can be controlled so as to avoid the position where it is impossible to start.

Current and torque applied to the 1-phase motor may be performed based on a PWM signal.

When the driving command of the 1-phase motor is reached to the motor driving device, it is preferable that the motor driving device change the driving method of the 1-phase motor according to whether or not the 3-phase motor is currently driven.

When the three-phase motor is being driven, the motor driving device is agitated for generating a forward/reverse rotation torque to the one-phase motor through driving of the upper switching element Sc and the lower switching element Sc_bar. It can be controlled to inject current.

When a driving command of the three-phase motor is reached to the motor driving device, it is preferable that the motor driving device change the driving method of the three-phase motor according to whether or not the one-phase motor is currently driven.

The motor drive device, when the one-phase motor is stopped, the upper DC link voltage (V1) and the lower DC link voltage to the three-phase motor through the two pairs of switching units (Sa, Sa_bar, Sb, Sb_bar) In a section in which all (V2) is applied, it is preferable to perform alignment of the three-phase motor in a section in which both voltages V2 and V1 are applied to the three-phase motor.

The motor driving device aligns the three-phase motor by applying only the voltage V2 to the three-phase motor in a section in which only the voltage V1 is applied to the one-phase motor when the one-phase motor is being driven, and the one-phase motor In a section in which only the voltage V2 is applied to the motor, it is preferable to align the three-phase motor by applying only the voltage V1 to the three-phase motor.

Features in the above-described embodiments may be applied in combination in other embodiments unless contradictory or exclusive.

According to an embodiment of the present invention, it is possible to provide a motor driving apparatus and a control method thereof capable of effectively performing parallel operation of a 1-phase motor and a 3-phase motor through a single inverter.

Through an embodiment of the present invention, it is possible to provide a motor alignment method capable of eliminating the inability to start a 1-phase motor and maximizing a starting torque.

Through an embodiment of the present invention, it is possible to provide a motor alignment method capable of maximizing starting torque in a three-phase motor.

According to an embodiment of the present invention, it is possible to provide a motor driving apparatus and a control method thereof capable of stably driving a 1-phase motor and a 3-phase motor by eliminating voltage imbalance.

1 is a circuit diagram of a motor driving apparatus according to an embodiment of the present invention;
2 is a circuit diagram of a motor driving apparatus according to another embodiment of the present invention;
3 is a circuit diagram of a motor driving apparatus according to another embodiment of the present invention;
4 is a control flowchart of a control method according to an embodiment of the present invention;
5 is a circuit diagram intuitively illustrating a case in which only a 1-phase motor is driven in the embodiment shown in FIG. 3;
6 is a simplified circuit diagram of a motor driving apparatus when only a single-phase motor is driven;
7 is a schematic diagram for explaining an on/off period of a one-phase swinging unit;
Fig. 8 is a schematic diagram schematically showing a position where the starting torque of the rotor of the one-phase motor is zero;
9 is a schematic diagram for explaining an on/off period of a 1-phase switching unit in 1-phase PWM control;
10 is a schematic diagram schematically showing an abnormal alignment position with respect to the rotor of the one-phase motor;
11 is a simplified circuit diagram of a motor driving apparatus when only a three-phase motor is driven;
12 is an output voltage vector according to a combination of a swinging unit when only a three-phase motor is driven;
13 is a simplified circuit diagram and an output voltage vector in a combination of two of the four switching units shown in FIG. 12;
14 is a simplified circuit diagram and an output voltage vector in a combination of the remaining two switching units among the four shown in FIG. 12;
15 is a sequential operation of a three-phase switching unit and a one-phase switching unit for solving the output voltage unbalance in an embodiment of the present invention; And
16 shows a sequential operation of a one-phase switching unit for solving an output voltage unbalance according to another embodiment of the present invention.

Hereinafter, a motor driving apparatus according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

First, a connection relationship between a motor driving apparatus 10 including a single inverter for controlling driving of a three-phase motor and a one-phase motor will be described in detail with reference to FIG. 1.

As shown, the inverter may be referred to as a 6B inverter 20 having six switching elements. However, in this embodiment, two switching elements (Sc, Sc_bar) are used to control the driving of the one-phase motor 40, and four switching elements (Sa, Sa_bar, Sb, Sb_bar) are three-phase motor 30 ) Can be used to control the drive. Accordingly, two switching elements and four switching elements may be connected to each other to form similar to a 6B inverter, and it may be possible to implement this embodiment through a single 6B inverter.

Of course, the motor driving device 10 may be separately provided with the three-phase motor 30 and the one-phase motor 10 and then connected to the three-phase motor and the one-phase motor. External AC power may be applied to the motor driving device 10, and other elements not shown may be included. In particular, an inverter driving unit or an inverter control unit for driving the inverter may be included in the motor driving device 10 or connected to the motor driving device 10.

Two upper and lower switching elements may be provided to apply a current in a specific phase as a pair. That is, it may be provided to apply a current of any one of phases a, b, and c. In the left pair of switching elements, the inverter leg C node may be connected to a phase a terminal of a three-phase motor. The inverter leg A node in the middle pair of switching elements may be connected to the b-phase terminal of the three-phase motor. In addition, the inverter rack B node of the right pair of switching elements may be connected to the c terminal of the 1-phase motor, and the neutral terminal n node may be connected to the c-phase terminal of the 3-phase motor and the t2 terminal of the 1-phase motor.

Here, the neutral end (n) refers to a connection point of the upper and lower divided DC-link capacitors (Ca, Cb), and the inverter 10 has such a neutral end (n). In addition, one pair of switching units (one-phase switching unit) may be provided for controlling the one-phase motor, and the other two pairs of switching units (three-phase switching unit) may be provided for controlling the three-phase motor.

In the example illustrated in FIG. 1, the three-phase switching unit may be referred to as switching elements Sc, Sc_bar, Sa, and Sa_bar, and the one-phase switching unit may be referred to as switching elements Sb and Sb_bar.

Accordingly, the three-phase switching unit may be provided to be connected to the a-phase terminal and the b-phase terminal of the three-phase motor, respectively, and the one-phase switching unit may be provided to be connected to the first terminal (t1) of the one-phase motor. And the neutral end (n) may be provided to be connected to the c-phase terminal of the three-phase motor and the second terminal (t2) of the 1-phase motor. The connection extending from the neutral terminal (n) is branched and connected to the c-phase terminal of the three-phase motor and the second terminal (t2) of the 1-phase motor, respectively.

In addition, in order to control the driving of the three-phase motor, the three-phase switching unit is provided to be connected to the a-phase terminal and the b-phase terminal of the three-phase motor, respectively, and the neutral terminal (n) is the c-phase terminal of the three-phase motor and After being connected, the driving of the three-phase motor is controlled by the three-phase switching unit.

In addition, in order to control the drive of the 1-phase motor, the 1-phase switching unit is connected to the first terminal (t1) of the 1-phase motor, and the second terminal (t2) of the 1-phase motor is connected to the middle end (n) and After being connected, driving of the one-phase motor is controlled by the one-phase switching unit.

Through such a connection relationship, when the 1-phase motor and the 3-phase motor are simultaneously driven, the 1-phase motor and the 3-phase motor are interlocked and controlled to be driven in parallel through the 1-phase switching unit and the 3-phase switching unit.

Meanwhile, the wiring structure may be variously changed through the inverter 20 having three pairs of switching elements. That is, it may be changed according to which one of the three pairs of switching units is connected to the one-phase motor.

FIG. 1 shows an embodiment in which a pair of right switching elements are connected to a 1-phase motor, FIG. 2 shows an embodiment in which a pair of middle switching elements are connected to a 1-phase motor, and FIG. 3 is a left An embodiment in which a pair of switching elements are connected to a one-phase motor is shown.

Therefore, various wiring changes are possible through the 6B inverter. In other words, this means that in an inverter having three phases a, b, and c, any one of phases a, b, and c can be used for a 1-phase motor as needed. That is, the positions of the three-phase motor and the one-phase motor or the position of the switching element connected to the one-phase motor for convenience of connection may be varied.

Hereinafter, a control method of a motor driving apparatus according to an embodiment of the present invention will be described in detail with reference to FIG. 4.

4 shows a control flow according to an embodiment of the present invention. For convenience of explanation, it is illustrated on the premise that the c phase of the a, b, and c phases is used for a 1-phase motor. That is, a method of aligning a one-phase motor, a method of aligning a three-phase motor, and a method of minimizing output voltage imbalance will be described in detail using the connection structure (total drive system) shown in FIG. 3.

As shown in FIG. 4, a method of controlling a motor driving apparatus according to an exemplary embodiment of the present invention may specifically relate to a parallel operation method of a single inverter-based 1-phase and 3-phase motor. That is, the 1-phase motor and the 3-phase motor can be controlled through a single inverter, but can be driven or stopped independently of each other. Of course, in a strict sense, the 1-phase motor and 3-phase motor may not be driven independently. This is because the one-phase switching unit is substantially shared for controlling the one-phase motor and the three-phase motor. The case where only each motor is driven can be said to be out of the question, but if each motor is driven at the same time, they are bound to be affected by each other. Of course, it would be desirable to minimize these effects to enable substantially independent driving.

A drive command for a 1-phase motor and/or a 3-phase motor may be transmitted to the motor driving device through the processor of the home appliance. By receiving such a command from the motor driving apparatus, the control method according to the embodiment of the present invention can be started (S10).

For convenience of explanation, for the parallel operation method of a single inverter-based 1-phase and 3-phase motor, when starting only a 1-phase motor (S20), starting only a 3-phase motor (S30), and a 1-phase motor A case where the and the three-phase motors start driving at the same time (S40) will be sequentially described.

When a driving command of the 1-phase motor is received (S20), control for driving the 1-phase motor may be performed. At this time, a step (S21) of determining whether the three-phase motor is being driven may be performed. When the three-phase motor is being driven, the method for driving the one-phase motor is different.

The alignment method of the 1-phase motor for driving the 1-phase motor is as follows.

First, a case where the three-phase motor is not driven will be described.

As shown in FIG. 5, when only the 1-phase motor is driven, the inverter part for controlling the 3-phase motor and the 3-phase motor among the entire motor driving system may be considered to be in a non-use state. That is, the three-phase motor is not driven. Therefore, switching elements and connections used may be displayed in black (or dark color), and unused switching elements and connections may be displayed in gray (or light colored). In this case, the entire motor drive system can be represented by a simple circuit as shown in FIG. 6.

The one-phase motor has a feature that does not generate starting torque at a specific position coincident with the voltage and current vector directions. In order to avoid such a specific position, it is possible to define mode A when the upper switch Sc is on and mode B when the lower switch Sc_bar is on.

In the simplified circuit diagram shown in FIG. 6, in the case of mode A, a connection through which current flows may be displayed in blue, and a connection through which no current flows is displayed in gray (or light blue). In addition, in the case of mode B, a connection through which current is flowing may be displayed in red, and a connection through which no current is flowing may be displayed in gray (or light blue). Accordingly, as the upper switch Sc and the lower switch Sc_bar are alternately turned ON/OFF, an alternating current is applied to the 1-phase motor (S22). That is, as shown in FIG. 4, by injecting a stirring current, the alignment of the 1-phase motor, that is, the position of the rotor of the 1-phase motor is aligned. Of course, normal driving is performed after the rotor is aligned.

Here, the upper switch Sc and the lower switch Sc_bar cannot be turned on at the same time to prevent an arm short, and the dead-time and idle-time are reflected in consideration of circuit and device characteristics. It is desirable to perform a complementary operation.

That is, it is preferable that the operation of the upper switching element Sc and the lower switching element Sc_bar is performed in consideration of the intrinsic characteristics of the element and the circuit, such as dead time and idle time. Specifically, when the upper switching element Sc and the lower switching element Sc_bar are operated, the maximum time for ON and OFF is set to be smaller than the sum of the dead time and the idle time and controlled. desirable.

The alignment method of the 1-phase motor may be summarized and expressed in a timing sequence shown in FIG. 7.

For the entire period T, if the ratio of time T1 when Sc is turned on and time T2 when Sc_bar is turned on is differently set according to motor characteristics (parameters such as dead time and idle time), Sc or Sc_bar is continuously turned on. By doing so, it is possible to avoid the point where starting torque is not generated.

In other words, it can be said that the rotor is moved out of the non-startable area through the injection of current to be changed or agitated. At this time, the ratio of the applied T1 and T2 times may be made symmetrically or asymmetrically according to the motor parameter. However, it is preferable to fix this ratio to apply current and perform the operation of aligning the rotor position.

Fig. 8 shows two positions where the starting torque becomes 0 (zero). That is, when the direction of the magnetic field in the stator and the direction of the magnetic field in the rotor are the same, the force is balanced and the starting torque can be zero.

A voltage applied as a short PWM signal (switching signal) as shown in FIG. 7 within a switching frequency section operating at several kHz cannot generate current and torque that make the motor move.

Therefore, in practice, as shown in FIG. 9, the 1-phase motor is aligned through current and torque applied through a switching signal based on PWM control. The initial position of the rotor can be changed in an arbitrary direction through an asymmetric current and torque application. That is, as shown, the initial position of the rotor may be changed by a difference between the integral value of the positive current amount and the integral value of the negative current amount. For example, when the positive current amount is greater than the negative current amount, the N pole of the rotor is moved to the face of the phase a of the stator.

Here, the waveform of the switching signal, that is, the current and torque waveforms are illustrated as a sine wave. However, it would be possible to transform into a square wave or trapezoidal wave.

In summary, when the 3-phase motor is stopped, a pulsating current is injected to align the rotor of the 1-phase motor, and then the 1-phase motor is started (S22). That is, by injecting the alternating current, the rotor is aligned to the initial alignment position, and the initial alignment position may be referred to as a position avoiding the above-described maneuverable position.

Specifically, as shown in FIG. 10, after placing the rotor in an ideal initial alignment position, a current for generating a forward/reverse rotation torque is injected so that the rotor starts. The ideal initial alignment position differs depending on the direction of rotation. That is, FIG. 10(a) shows an ideal initial alignment position for rotating the rotor in a counterclockwise direction, while FIG. 10(b) shows an ideal initial alignment position for rotating the rotor in a clockwise direction. Of course, in consideration of the rotation direction of the rotor, it can be aligned to one of two ideal positions. However, any one of the two can be arbitrarily set as such an initial position, and any one can be set as a default value.

This is because, for example, a separate algorithm circuit that detects the direction of rotation or mechanical components through a bearing that allows unidirectional rotation may be additionally provided. This is because if abnormal rotation is detected through these components or algorithms (for example, when rotating clockwise but rotating counterclockwise), normal rotation direction of the rotor can be performed by performing alignment and restart again after stopping. .

When the three-phase motor is stopped, alignment and starting of the one-phase motor and normal operation control are possible only by driving the one-phase switching unit.

Next, a method of aligning the 1-phase motor when the 3-phase motor is running will be described.

When the three-phase motor is being driven, it is preferable to perform another alignment method in the one-phase motor as described above. Of course, even in this case, a stirring current must be injected for the alignment of the single-phase motor, particularly the position of the rotor. However, in this case, the stirring current must be injected by synthesis.

When a three-phase motor is being driven when performing the drive command S20 of the one-phase motor, a step for synthesizing the alternating current is performed. That is, through the driving of the upper switching element (Sc) and the lower switching element (Sc_bar), the 1-phase motor is controlled to inject a stirring current for generating a forward/reverse rotation torque.

First, in the section in which the 3-phase motor uses only the lower DC link voltage (V2) voltage, that is, in the section (Sa, Sb) = (0,0), the upper DC through switching (Sc = 1) is a sequence that turns on the upper switch. -Link (V1) voltage is used to output a positive current to align a 1-phase motor. On the contrary, in the section in which the 3-phase motor uses only the upper DC link voltage (V1) voltage, that is, in the section (Sa, Sb) = (1,1), the lower DC link through switching (Sc = 0), a sequence that turns on the lower switch. Voltage imbalance is eliminated by outputting negative current for aligning 1-phase motors using voltage (V2).

In other words, the motor driving device is a section in which only the upper DC link voltage (V1) is applied to the three-phase motor through the three-phase switching unit (Sa, Sa_bar, Sb, Sb_bar) and only the lower DC link voltage (V2) is applied. In, it is preferable to control the stirring current to be injected into the 1-phase motor.

More specifically, the upper switching element Sc is turned on in a section where only the voltage V2 is applied to the three-phase motor to output a positive current, and in the section where only the voltage V1 is applied to the three-phase motor, the lower switching element Sc_bar ) Is turned on to output negative current. Therefore, it is possible to reduce the voltage imbalance applied to the three-phase motor by using only such a specific section. In other words, the alignment of the 1-phase motor is not performed in the section outputting both the V1 voltage and the V2 voltage through the 3-phase switching unit, and the alignment of the 1-phase motor is performed in the section outputting only the V1 voltage or the V2 voltage. Voltage imbalance can be effectively reduced.

Hereinafter, a case where only the three-phase motor starts driving (S30) will be described.

Alignment in a three-phase motor is a general sequence of initializing the electric angle of the motor control. In a 6B inverter, for example, when a positive current is applied to the A phase, the N pole is generally aligned to the corresponding position of the winding on the A phase. However, in the case of the B4 inverter, each winding current is aligned in a deflected position rather than a corresponding position. That is, it can be said that a difference in the alignment position of the initial rotor occurs.

This embodiment considers this difference and proposes a method for effectively aligning the three-phase motors when the one-phase and three-phase motors are operated in parallel through a single inverter.

As shown in Fig. 11, the entire system (see Figs. 3 and 5) can be briefly represented. That is, a 1-phase motor and a 1-phase switching unit for controlling the 1-phase motor may be omitted and briefly displayed.

In this case, there are four combinations of the output voltage of the 4B inverter for the three-phase motor as shown in FIG. 12. In the conventional 6B inverter, A, B, C phases, that is, three positioning may occur, but in this embodiment, four positioning may be generated by a combination of operations of the three-phase switching unit. In particular, the rotor is not positioned at a position facing a specific phase, but the rotor is aligned at a position corresponding to the output voltage and current vector.

13 and 14 show the switching combination, current flow, current direction and voltage vector in these four combinations.

When a driving command of the three-phase motor is generated (S30), it is determined whether or not the one-phase motor is driven (S31). In addition, it is preferable that the alignment method of the three-phase motor varies depending on whether the one-phase motor is driven.

First, a case where the 1-phase motor is stopped will be described.

13 and 14, the combination with the largest output voltage is the condition (Sa, Sb) = (1,0) and the condition (Sa, Sb) = (0,1). That is, the voltage vector is the largest in the two conditions or combinations. Accordingly, the three-phase motor is aligned by generating the largest voltage vector (S32), and then the three-phase motor is aligned using two voltage vectors. Thereafter, the three-phase motor can be controlled to start and operate normally.

That is, for motor alignment, the motor may be aligned under any one of the two conditions. Of course, it is also possible to set only one of the two conditions as a default value.

Specifically, when the 1-phase motor is stopped, the 3-phase motor is operated using a section in which both the upper DC link voltage (V1) and the lower DC link voltage (V2) are applied to the 4-phase motor through the 3-phase switching unit. Align. That is, by artificially controlling the three-phase switching unit so that both voltages V1 and V2 are applied, the three-phase motors are aligned. The on/off state of the three-phase switching unit or a combination of signals of the three-phase switching unit at this time are well shown in FIGS. 13 and 14.

Next, alignment of the three-phase motor when the one-phase motor is operating will be described.

The sequence of turning on the upper switch (Sc) among the 1-phase switching units (Sc, Sc_bar), that is, when (Sc = 1), uses the upper DC link voltage (V1) voltage, so in this section, the 3-phase switching unit (Sa, Sa_bar) is used. , Sb, Sb_bar), it is preferable to align the three-phase motor using a sequence using only the lower DC link voltage V2, that is, (Sa, Sb) = (0,0). This can be solved by voltage imbalance.

Conversely, the sequence of turning on the lower switch (Sc_bar) among the 1-phase switching units (Sc, Sc_bar), that is, when (Sc = 0), the lower DC link voltage (V2) is used. In this section, only the upper DC link voltage (V1) is used. Align the three-phase motor using the sequence used, i.e. (Sa, Sb) = (1,1) switching combination condition.

That is, when the 1-phase motor is being driven, unlike when the 1-phase motor is being stopped, it is desirable to minimize this in consideration of voltage imbalance. Therefore, in this case, in order to minimize voltage imbalance, alignment of the three-phase motor may be performed by controlling the three-phase switching unit to use the voltage V2 in the three-phase motor in the section where the voltage V1 is used in the one-phase motor (S36). ). In addition, alignment of the three-phase motor may be performed by controlling the three-phase switching unit to use the voltage V1 in the three-phase motor in a section in which the voltage V2 is used in the one-phase motor (S36).

Therefore, when the three-phase motors are aligned, the driving combinations of the three-phase switching units are different depending on whether the one-phase motor is driven. That is, in some cases, alignment is performed using a large force, and in other cases, alignment is performed by minimizing voltage imbalance. In the former case, since voltage imbalance does not occur, it is possible to perform alignment using a large force, and in the latter case, it can be said that it is a more effective alignment method to resolve voltage imbalance rather than using a large force. have.

Of course, when the 1-phase motor is being driven, the 3-phase motor can be aligned through a combination of other switching units as described above. In this case, the condition of the speed or the load below the critical point may be set. That is, even if the 1-phase motor is in operation, the 3-phase motor can be aligned under the conditions (Sa, Sb) = (1,0) and (Sa, Sb) = (0,1). In this case, a voltage sensor capable of measuring both voltages (V1, V2) of the upper and lower divided DCs may be provided, a voltage estimation algorithm may be applied, or a low 1-phase motor driving current condition may be applied. That is, it will be possible to be limitedly applied in the condition of speed or load below the critical point.

However, in this case, it is not easy to set the threshold, and there is a problem that the control algorithm of the motor becomes complicated. Of course, for precise control and immediate driving of a three-phase motor, it will be possible to set a threshold and control by setting different conditions below the threshold and the conditions above the threshold, or the conditions below the threshold and above the threshold.

Hereinafter, when both the three-phase motor and the one-phase motor are stopped, a driving method will be described.

First, when a simultaneous drive command is generated for two motors, it may be controlled to drive either motor first. When such a driving command is reached, the motor driving apparatus may sequentially perform it. Of course, it is possible to sequentially transmit the driving command from the processor of the home appliance that transmits the driving command to the motor driving device.

Specifically, the motor driving apparatus may control the other motor to be driven after a predetermined time after one motor is driven.

In addition, when the driving command of the 1-phase motor and the driving command of the 3-phase motor reach the motor driving device at the same time, the motor driving device first drives one of the 1-phase motor and the 3-phase motor, and then the other. It can be controlled to drive. Through this, complex control algorithms can be avoided, and expected voltage imbalance can be prevented or minimized.

In order to solve the voltage imbalance, in a state in which the three-phase motors are all started and driven, the speeds of the one-phase motor and the three-phase motor are different from the case where the speeds of the one-phase motor and the three-phase motor are the same. It is desirable to control parallel operation.

That is, in the simultaneous driving condition (S40) of the 1-phase motor and the 3-phase motor, a step of determining whether the speeds of both are the same (S41) may be performed, and the control method may be different according to the result.

When both 1-phase and 3-phase motors are driven, current ripple occurs if the output voltage imbalance is not controlled early, and the life of the vertically divided DC link capacitors (Ca, Cb) is reduced, and in severe cases, it is out of phase. Motor stoppage may occur due to the phenomenon. Therefore, when both the 1-phase motor and the 3-phase motor are driven, it is highly desirable to eliminate the output voltage imbalance early.

First, when both motors are accelerated at the same speed or driven at the same speed, voltage vector cross-alignment (mis-align) may be performed (S43). When both motors are driven in different degrees, one-phase motor buffering may be performed (S42).

The voltage vector cross alignment will be described in detail.

When the electric angle of the three-phase motor is 90 degrees, the electric angle of the one-phase motor is 180, which is different from each other. Therefore, it is not easy to solve the voltage imbalance due to the difference in angle. In this embodiment, in order to solve this problem, a method of solving voltage unbalance in different conditions under different conditions is proposed.

FIG. 15 shows a switching flow chart when a 1-phase motor and a 3-phase motor are simultaneously driven. The voltage applied to the three-phase motor (upper view) and the voltage applied to the 1-phase motor (lower view) according to the switching of the respective switches are also shown.

Under simultaneous acceleration (same acceleration slope) or the same driving speed condition, the voltage vector of the 1-phase motor is output at a specific electric angle position in synchronization with the position information and rotation speed of the 3-phase motor. The voltage of the DC link capacitor used is different according to the switching conditions of the 1-phase motor and 3-phase motor. Therefore, when the maximum voltage output positions of each motor are the same, voltage unbalance can be maximized. Therefore, in this embodiment, the voltage unbalance can be minimized by making the maximum voltage output positions of each motor cross or deviate.

Through this, it is also possible to improve the responsiveness to the load torque.

When the DC voltage is Vdc, the voltage on a is Vas, the voltage on b is Vbs, and the voltage on c is Vcs. The changes in the a-phase voltage, b-phase voltage, and c-phase voltage are shown by green, red, and blue lines, respectively.

As the switching conditions (Sa, Sb) change to (0, 0), (1, 1), (1, 0) and (0, 1), respectively, the voltage of each phase varies.

As shown, under the (0, 0) condition, Vas = Vbs =-Vdc/6, and Vcs = Vdc/3. In the (1, 1) condition, it can be seen that Vas = Vbs = Vdc/6 and Vcs =-Vdc/3. In the (1, 0) condition, it can be seen that Vas = 1/2Vdc, Vbs = -1/2Vdc and Vcs = 0. In the (0, 1) condition, it can be seen that Vas = -1/2Vdc, Vbs = 1/2Vdc and Vcs = 0.

As shown, in the (1, 0) and (0, 1) conditions, which are the conditions in which the voltage of the phase a and the voltage of the b phase are maximized, that is, the voltage of the phase c (which is also applied to the phase 1 motor and is applied to the phase 1 motor) It can be seen that the voltage shared by the 3-phase motor) becomes 0. Conversely, it can be seen that in the (0, 0) and (1, 1) conditions, that is, the conditions in which the voltage of the phase c becomes the maximum, that is, the voltage of the phase a and the phase b is lower than the maximum value.

Accordingly, by varying the maximum voltage output position (that is, the time point) of each motor, it is possible to reduce the voltage unbalance.

As shown in FIG. 15, if the characteristic values (parameters) of the 1-phase motor and 3-phase motor are different, there may be a phase change in the voltage vector output position. However, it can be seen that each phase difference is constant and fixed. Therefore, by applying this embodiment, the electrical frequencies of the two motors are matched.

Next, a one-phase motor buffering method that can be used when the driving conditions of the quantum motors are different will be described.

As shown in Fig. 16, when the driving conditions of the two motors are different, the control of the three-phase motor is maintained and the control method of the one-phase motor can be changed. That is, the control for the three-phase switching unit can be maintained and the control for the one-phase switching unit can be changed.

That is, all of the control for solving the voltage imbalance of the divided DC link capacitor can be performed through the control of the 1-phase motor. This can be said to allocate all of the additional torque ripple that may be caused by the output voltage unbalance to the 1-phase motor, not the 3-phase motor. This is because it is more effective in device control to buffer the inevitable torque ripple in a 1-phase motor rather than a 3-phase motor. That is, it is because the torque ripple reduction in a device using a three-phase motor is more effective than in a device using a 1-phase motor.

For example, when controlling the drum drive motor and the drain pump motor of a washing machine in parallel, a three-phase motor may be used for the drum drive motor and a one-phase motor may be used for the drain pump motor for more precise control. Therefore, it is preferable that the torque ripple reduction in the drum drive motor takes precedence over the torque ripple reduction in the drain pump motor. For the same reason, when the driving speeds of both motors are different, it is preferable to buffer all of the voltage imbalance problems in the one-phase motor.

For this buffering, as shown in FIG. 16, the period of the 1-phase switching unit may be changed.

When V1 <V2, 1 section can be decreased and 2 sections are increased within 1 cycle, and when V1> V2, 1 section can be increased and 2 sections can be decreased within 1 cycle.

That is, when a voltage imbalance occurs in which V1 and V2 are different from each other, the voltage imbalance can be eliminated by changing the V2 output time and the V1 output time.

Specifically, when V2 is large, V2 output time can be increased (this means a decrease in V1 output time) so that V1 and V2 become the same. Conversely, when V1 is large, V1 output time is increased, It can be controlled so that V1 and V2 become the same.

The increase or decrease in section 1 and section 2 may be performed proportionally. That is, the increase or decrease is performed at the same rate within one cycle, and this rate may be kept the same as the cycle progresses. That is, if section 1 increases by 10% within one cycle, section 2 decreases by 10%. This pattern can be maintained even when the next cycle is performed. That is, it can be maintained until the imbalance between V1 and V2 is resolved. Thereafter, when the imbalance between V1 and V2 is resolved, the first section and the second section can be controlled so that they have the same interval.

Through this one-phase motor buffering method, the torque ripple in the one-phase motor is inevitably increased, but the increase in unbalance is minimized and the torque ripple can be controlled to an acceptable level.

Therefore, even when the voltages of V1 and V2 are different, as an example of a control pattern of a three-phase motor, the duty ratio can be maintained and controlled as the same. Accordingly, the control pattern of the three-phase motor, which requires more precise control, is kept unchanged, and conversely, the control pattern of the one-phase motor is changed if necessary, thereby minimizing voltage unbalance.

Meanwhile, in the above-described embodiments, a control method in each case has been described when the 1-phase motor and the 3-phase motor are operated in parallel.

However, due to the characteristics of a home appliance including a three-phase motor and a one-phase motor and a motor driving device for driving and controlling them through one inverter, all of the above-described cases may not occur.

For example, it may be a home appliance in which a three-phase motor and a one-phase motor are not driven at the same time. In particular, both may be driven during normal operation, but driving times may be sequential. In addition, when both are driven, it may be a home appliance that is driven at the same speed.

Therefore, even if the motor driving apparatus according to the present embodiment described above is applied to a specific home appliance, the control method in all cases may not be necessary.

10: motor drive device 20: inverter
30: 3-phase motor 40: 1-phase motor
n: Inverter neutral terminal

Claims (24)

The upper and lower switching elements form a pair of switching units, and the three-phase motor and the one-phase motor are controlled in parallel operation through an inverter having a total of three pairs of switching units and a connection point (neutral end) of the upper and lower divided DC-link capacitors. In the provided motor drive device,
Two pairs of switching units (three-phase switching units) are provided to be connected to the a-phase and b-phase terminals of the three-phase motor, respectively, and the other pair of switching units (1-phase switching unit) is the first terminal of the one-phase motor and And the neutral terminal is provided to be connected to the c-phase terminal of the three-phase motor and the second terminal of the one-phase motor. The method of claim 1,
The upper switching element (Sc) and the lower switching element (Sc_bar) of the one-phase switching unit operate complementarily to prevent an arm short, and control to be simultaneously turned on. The method of claim 2,
The operation of the upper switching element Sc and the lower switching element Sc_bar is performed in consideration of a dead time and an idle time, which are inherent characteristics of the element. The method of claim 3,
When the upper switching element (Sc) and the lower switching element (Sc_bar) operate, the maximum time at the time of on and off is set to be smaller than the sum of the dead time and the idle time, and is controlled. Motor drive. The method of claim 2,
When the driving command of the 1-phase motor is reached to the motor driving device, the motor driving device performs alignment so that the rotor of the 1-phase motor avoids a position incapable of starting, and then controls the 1-phase motor to be driven. Motor drive device, characterized in that. The method of claim 5,
The motor driving device is characterized in that by injecting a stirring current to the 1-phase motor through driving of the upper switching element Sc and the lower switching element Sc_bar, and controlling the rotor to avoid a position in which it cannot be started. Motor drive. The method of claim 6,
The motor driving device is characterized in that the ratio of the on time (T1) of the upper switching element (Sc) and the off time (T2) of the lower switching element (Sc_bar) is differently set and controlled. Motor drive. The method of claim 5,
The motor driving device is configured to generate the first phase by turning on the current and torque applied to the one-phase motor by turning on the upper switching element Sc and turning on the lower switching element Sc. The motor driving apparatus according to claim 1, wherein the values of the current and torque applied to the motor are different, and the rotor is controlled to avoid a position in which the start is impossible. The method of claim 8,
A motor driving device, characterized in that the current and torque applied to the 1-phase motor are performed based on a PWM signal. The method of claim 9,
The waveform of the PWM signal is a motor driving apparatus, characterized in that any one of a sine waveform, a square waveform, or a trapezoidal waveform. The method according to any one of claims 5 to 10,
When a driving command of the 1-phase motor is reached to the motor driving apparatus, the motor driving apparatus changes a driving method of the 1-phase motor according to whether or not the 3-phase motor is currently driven. The method of claim 11,
When the three-phase motor is driven, the motor driving device is agitated to generate a forward/reverse rotation torque to the one-phase motor through driving of the upper switching element Sc and the lower switching element Sc_bar. Motor drive device, characterized in that controlling to inject current. The method of claim 12,
The motor driving device is a section in which only the upper DC link voltage (V1) is applied to the three-phase motor through the two pairs of switching units (Sa, Sa_bar, Sb, Sb_bar) and only the lower DC link voltage (V2) is applied. In the section, the motor driving device, characterized in that controlling so that the stirring current is injected into the 1-phase motor. The method of claim 13,
The motor driving device outputs a positive current by driving the upper switching element Sc to On in a section in which only the voltage V2 is applied to the three-phase motor, and in a section in which only V1 voltage is applied to the three-phase motor. A motor driving apparatus, characterized in that the lower switching element Sc_bar is driven on to output a negative current, thereby reducing voltage imbalance applied to the three-phase motor. The method according to any one of claims 5 to 10,
When a driving command of the three-phase motor is reached to the motor driving device, the motor driving device changes a driving method of the three-phase motor according to whether or not the one-phase motor is currently driven. The method of claim 15,
The motor drive device, when the one-phase motor is stopped, the upper DC link voltage (V1) and the lower DC link voltage to the three-phase motor through the two pairs of switching units (Sa, Sa_bar, Sb, Sb_bar) A motor driving apparatus, characterized in that, in a section in which all (V2) is applied, the three-phase motor is aligned in a section in which both voltages V2 and V1 are applied to the three-phase motor. The method of claim 15,
The motor driving device aligns the three-phase motor by applying only the voltage V2 to the three-phase motor in a section in which only the voltage V1 is applied to the one-phase motor when the one-phase motor is being driven, and the one-phase motor A motor driving apparatus, characterized in that in a section in which only the voltage V2 is applied to the motor, the three-phase motor is aligned by applying only the voltage V1 to the three-phase motor. The method according to any one of claims 5 to 10,
When the driving command of the 1-phase motor and the driving command of the 3-phase motor reach the motor driving device at the same time, the motor driving device first drives one of the 1-phase motor and the 3-phase motor, and then drives the other. Motor drive device, characterized in that to control so as to. The method according to any one of claims 5 to 10,
And the motor driving device is configured to control the other motor to be driven after a predetermined time after one motor is driven in a state in which both the one-phase motor and the three-phase motor are stopped. The method according to any one of claims 5 to 10,
In order to reduce the output voltage imbalance in the three-phase motor, the motor driving device is provided in a state in which both the one-phase motor and the three-phase motor are driven and the speeds of the one-phase motor and the three-phase motor are the same. And differently controlling a maximum voltage output position of the 1-phase motor and a maximum voltage output position of the 3-phase motor. The method according to any one of claims 5 to 10,
In order to reduce the output voltage imbalance in the three-phase motor, the motor driving device is provided under a condition in which the speeds of the one-phase motor and the three-phase motor are different when both the one-phase motor and the three-phase motor are driven. And controlling the ratio of the section in which only the upper DC link voltage V1 applied to the 1-phase motor is applied and the section in which only the lower DC link voltage V2 is applied to be different. The method of claim 21,
The motor driving device,
When V2 is greater than V1, the driving of the 1-phase switching unit is controlled so that the section in which only the V1 is applied is reduced and the section in which only the V2 is applied is increased within one cycle,
When V2 is smaller than V1, the driving of the 1-phase switching unit is controlled so that a section in which only V1 is applied is increased and a section in which only V2 is applied is decreased within one cycle. The method of claim 22,
The motor driving device is a motor driving device, characterized in that proportionally performing the decrease and increase of the section as a cycle progresses. The method of claim 22,
The motor driving device is characterized in that, even when the V1 and V2 are different from each other, the duty ratio of the three-phase switching unit is controlled to remain the same.

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