KR20200108606A - Inverter Control Device - Google Patents

Abstract

The present invention provides an inverter control device, including: a motor; an inverter including first to sixth switches and converting DC power into AC power to supply power to the motor; first to second current sensors each measuring phase currents flowing in two phase connections among three-phase connections between the motor and the inverter; and a control unit controlling turning on/off of two switches of the first to sixth switches, determining the phase-to-phase short circuit or phase-open of the motor based on the phase currents measured by at least one of the first and second current sensors, and adjusting the gain of the first and second current sensors. The inverter control device is capable of preventing damage to the inverter and the motor caused by a switch failure when driving the inverter.

Description

Inverter Control Device {Inverter Control Device}

The present invention relates to an inverter control device.

An inverter is a device that converts DC power into AC power and supplies it to a motor. Such an inverter includes a plurality of semiconductor switches, and converts DC power into AC power by controlling the on-off duty ratio of the plurality of semiconductor switches and outputs the converted power.

On the other hand, when a failure occurs in a semiconductor switch provided in the inverter, there is a problem in that the failure causes damage to the inverter and the motor when driving the motor and the inverter.

In addition, when a failure such as a short circuit and an open phase occurs in the motor, there is a problem in that the motor and the inverter are damaged due to such a short circuit and an open phase when driving the inverter and the motor.

On the other hand, torque ripple may occur due to motor driving. Here, the torque ripple is caused by a gain error occurring on the path through which the current detected by the current sensor is transmitted or on the amplifier inside the current sensor. There is a problem in that the control performance of the motor is deteriorated due to such torque reflow.

An object of the present invention is to provide an inverter control device capable of determining whether or not each switch has a failure by controlling the on/off of each switch of the inverter and comparing the current of each phase.

In addition, an object of the present invention is to provide an inverter control device capable of preventing damage to the inverter and the motor caused by a switch failure when driving the inverter.

In addition, an object of the present invention is to provide an inverter control device capable of determining whether or not a motor has a failure (inter-phase short circuit and phase open) by controlling the ON/OFF of each switch of the inverter and comparing each phase current.

In addition, an object of the present invention is to provide an inverter control device capable of preventing damage to an inverter and a motor caused by phase-to-phase short-circuit and phase opening during driving of the inverter.

Another object of the present invention is to provide an inverter control device capable of adjusting the gain of a current sensor by controlling the on-off of each switch of the inverter and comparing the currents of each phase.

In addition, an object of the present invention is to provide an inverter control device capable of reducing torque ripple generated in a motor when driving the inverter.

In order to achieve the above object, a motor, an inverter including the first to sixth switches, converting DC power into AC power and supplying it to the motor, and a phase flowing in two phase connections among the three phase connections between the motor and the inverter. Based on the phase current measured by at least one of the first and second current sensors by controlling on and off of the first and second current sensors respectively measuring current and two of the first to sixth switches It provides an inverter control device including a control unit for determining whether the motor is short-circuited or open, and adjusting gains of first and second current sensors.

Here, if the magnitude of the phase current measured by at least one of the first and second current sensors is determined to be an overcurrent that is equal to or greater than the first reference value, the controller may determine the phase-to-phase short circuit.

In addition, if the magnitude of the phase current measured by at least one of the first and second current sensors is determined to be a minute current equal to or less than the second reference value, the controller may determine that the phase is open.

Also, if the magnitudes of the phase currents measured by the first and second current sensors are different from each other, the controller may adjust the gains of the first and second current sensors so that the magnitudes of the phase currents respectively measured are the same.

In addition, the inverter includes first to third arms connected in parallel, the first arm includes first and fourth switches connected in series, the second arm includes second and fifth switches connected in series, and a third The arm may include third and sixth switches connected in series.

In addition, the contacts of the first and fourth switches are connected to the A-phase connection between the motor and the inverter, the contacts of the second and fifth switches are connected to the B-phase connection between the motor and the inverter, and the contacts of the third and sixth switches. Can be connected to the C-phase connection between the motor and inverter.

In addition, the first current sensor may measure the A-phase current flowing through the A-phase connection, and the second current sensor may measure the B-phase current flowing through the B-phase connection.

In addition, the control unit controls the on/off of the first and fifth switches, and if the magnitude of the A phase current or the B phase current is determined to be an overcurrent equal to or greater than the first reference value, it is determined as a short circuit between the A phase and B phase, and the A phase current or If the magnitude of the B phase current is determined to be a minute current equal to or less than the second reference value, it may be determined as an A phase or B phase open.

In addition, the control unit controls the on/off of the first and sixth switches, and if the magnitude of the A phase current is determined to be an overcurrent that is equal to or greater than the first reference value, it is determined as a short between the A phase and the C phase, and the magnitude of the A phase current is second If it is determined as a minute current below the reference value, it can be determined as an A phase or C phase open.

In addition, the control unit controls the on-off of the second and sixth switches, and if the magnitude of the B phase current is determined to be an overcurrent equal to or greater than the first reference value, it is determined as a short between the B phase and the C phase, and the magnitude of the B phase current is determined as a second If it is determined as a minute current below the reference value, it can be determined as the B phase or C phase open.

In addition, the control unit controls the on/off of the first and fifth switches, and if the magnitudes of the A phase current and the B phase current are different, the gain of the first and second current sensors is adjusted so that the magnitudes of the A phase current and B phase current are the same. Can be adjusted.

In addition, the control unit may determine whether any one of the remaining switches has failed by turning on one of the first to sixth switches and turning off the other switches.

In addition, the controller may determine whether a switch connected to the same arm as the turned-on switch has failed.

In addition, the controller may determine that a switch connected to the same arm is malfunctioning when a dark current flows through the turned-on switch.

According to the present invention, by controlling the on/off of each switch of the inverter and comparing the current of each phase, it is possible to determine whether each switch has failed, and through this, damage to the inverter and the motor caused by switch failure when driving the inverter. There is an effect that can be prevented in advance.

In addition, according to the present invention, by controlling the on-off of each switch of the inverter and comparing the current of each phase, it is possible to determine whether the motor has a failure (inter-phase short circuit and phase open). There is an effect of preventing damage to the inverter and motor caused by the phase opening.

In addition, according to the present invention, it is possible to adjust the gain of the current sensor by controlling the on/off of each switch of the inverter and comparing the current of each phase, and through this, it is possible to reduce the torque ripple generated in the motor when driving the inverter. It works.

The effects that can be obtained in the present invention are not limited to the above-mentioned effects, and other effects not mentioned may be clearly understood by those of ordinary skill in the art from the following description. will be.

1 is a schematic block diagram of an inverter control apparatus according to an embodiment of the present invention.
2 is a circuit diagram of an inverter and a motor according to an embodiment of the present invention.
3 is a table for explaining a method of determining whether a switch failure occurs by a control unit of the inverter control apparatus according to an embodiment of the present invention.
4 is a flowchart of FIG. 3.
5 is a table for explaining a method of determining whether a motor is short-circuited between phases and an open phase, and a method of adjusting a gain of a current sensor by a control unit of the inverter control apparatus according to an exemplary embodiment of the present invention.
6 is a flowchart of FIG. 5.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art can easily implement the present invention. The present invention may be implemented in various different forms, and is not limited to the embodiments described herein. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and the same reference numerals are assigned to the same or similar components throughout the specification.

In the present specification, terms such as "comprise" or "have" are intended to designate the presence of features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, but one or more other features. It is to be understood that the possibility of addition or presence of elements or numbers, steps, actions, components, parts, or combinations thereof is not preliminarily excluded.

1 is a schematic block diagram of an inverter control apparatus according to an embodiment of the present invention. And, Figure 2 is a circuit diagram of an inverter and a motor according to an embodiment of the present invention.

As shown in FIG. 1, the inverter control apparatus according to an embodiment of the present invention may include a motor 100, an inverter 200, a current sensor 300, and a control unit 400.

And, as shown in Figure 2, the motor 100 includes resistors (R1, R2, R3) and inductors (L1, L2, L3) connected in series to each phase (A, B, C), and the inverter ( 200) includes first to sixth switches SW1 to SW6, converts DC power into AC power, and supplies it to the motor 100.

The current sensor 300 is connected to at least two of the three-phase (A, B, C) connections between the motor 100 and the inverter 200 and measures a phase current flowing in each phase. Specifically, the current sensor 300 is connected to each of the three-phase (A, B, C) connection to measure the phase current flowing in each phase, but is connected to any two phase connection of the three phases, Is measured, and the phase current flowing through the other phase connection may be calculated through the measured two phase currents.

Hereinafter, the measurement and calculation of the phase current flowing through the connection of each phase (A, B, C) using two current sensors CS1 and CS2 will be described as an example.

As shown in FIG. 2, the first current sensor CS1 measures a phase A current flowing in the A phase among the phases A, B, and C of the motor 100, and the second current sensor CS2 The phase B current flowing in the B phase among the phases (A, B, C) of the motor 100 is measured. In addition, the C-phase current flowing in the C-phase may be calculated through the measured A-phase current and B-phase current.

In addition, the inverter 200 may include first to third arms connected in parallel.

Here, the first arm includes a first switch SW1 and a fourth switch SW4 connected in series, the second arm includes a second switch SW2 and a fifth switch SW5 connected in series, and a third The arm includes a third switch SW3 and a sixth switch SW6 connected in series.

In addition, the contacts of the first switch SW1 and the fourth switch SW4 are connected to the A-phase connection of the motor 100, and the contacts of the second switch SW2 and the fifth switch SW5 are the motor 100. It is connected to the B-phase connection of the third switch (SW3) and the sixth switch (SW6) is connected to the C-phase connection of the motor 100.

In addition, the inverter 200 may include a capacitor C connected in parallel with each arm. Here, the capacitor C serves to store DC power.

The control unit 400 of the inverter control apparatus according to an embodiment of the present invention turns on any one of the first to sixth switches SW1 to SW6 and turns the other switches off ( Turn-Off) to determine whether any one of the remaining switches has failed.

Specifically, the control unit 400 determines whether a switch connected to the same arm as the turned-on switch has failed. That is, if a dark current flows through the turned-on switch, it is determined as a failure of the switch connected to the same arm.

3 is a table for explaining a method of determining whether a switch failure occurs by a control unit of the inverter control apparatus according to an embodiment of the present invention. And, FIG. 4 is a flowchart of FIG. 3.

As shown in FIGS. 2 to 4, first, the controller 400 controls the first to sixth switches SW1 to SW6 in a mode off state (Mode0). In addition, when each phase current measured and calculated through the first and second current sensors CS1 and CS2 is 0, it is determined that the switches SW1 to SW6 of the inverter 200 are normal (Case0). .

However, when any one of the phase currents measured and calculated through the first current sensor CS1 and the second current sensor CS2 is not 0, it may be determined that a short circuit (SC) has occurred ( Case1).

Specifically, when the A-phase current is 0, it may be determined as a failure of the first switch SW1 and the fourth switch SW4 included in the first arm. In addition, when the B-phase current is not 0, it may be determined as a failure of the second switch SW2 and the fifth switch SW5 included in the second arm. In addition, when the C-phase current is not 0, it may be determined as a failure of the third switch SW3 and the sixth switch SW6 included in the third arm.

Next, the control unit 400 turns on the first switch SW1 and turns off the remaining switches SW2 to SW6 (Mode1). Here, when the A-phase current is not 0, since the first arm can be considered to be short-circuited (SC), it can be determined as a failure of the fourth switch SW4 connected in series with the first switch SW1 (Case2). .

Next, the control unit 400 turns on the second switch SW2 and turns the remaining switches SW1 and SW3 to SW6 off (Mode2). Here, when the B-phase current is not 0, since the second arm can be considered to be short-circuited (SC), it can be determined as a failure of the fifth switch SW5 connected in series with the second switch SW2 (Case3). .

Next, the controller 400 turns on the third switch SW3 and turns off the remaining switches SW1, SW2, and SW4 to SW6 (Mode3). Here, when the C-phase current is not 0, the third arm can be considered to be short-circuited (SC), and thus it can be determined as a failure of the sixth switch SW6 connected in series with the third switch SW3 (Case4). .

Next, the controller 400 turns on the fourth switch SW4 and turns off the remaining switches SW1 to SW3, SW5, and SW6 (Mode4). Here, when the A-phase current is not 0, since the first arm can be considered to be short-circuited (SC), it can be determined as a failure of the first switch SW1 connected in series with the fourth switch SW4 (Case5). .

Next, the controller 400 turns on the fifth switch SW5 and turns off the remaining switches SW1 to SW4 and SW6 (Mode5). Here, if the phase B current is not 0, it can be considered that the second arm is short-circuited (SC), and thus it can be determined as a failure of the second switch SW2 connected in series with the fifth switch SW5 (Case6). .

Next, the controller 400 turns on the sixth switch SW6 and turns off the remaining switches SW1 to SW5 (Mode6). Here, when the C-phase current is not 0, since the third arm can be considered to be short-circuited (SC), it can be determined as a failure of the third switch SW3 connected in series with the sixth switch SW6 (Case7). .

On the other hand, when it is determined that the first to sixth switches SW1 to SW6 have failed, the control unit 400 turns off all of the switches SW1 to SW6.

As described above, in the inverter control apparatus according to an embodiment of the present invention, the controller 400 controls the on/off of each switch SW1 to SW6 and compares the current of each phase, so that it is possible to determine whether or not each switch has a failure, Through this, damage to the inverter 200 and the motor 100 caused by a switch failure when driving the inverter 200 may be prevented in advance.

The control unit 400 of the inverter control apparatus according to the embodiment of the present invention controls on/off of two switches among the first to sixth switches SW1 to SW6, and the first current sensor CS1 and the second Based on the phase current measured by at least one of the current sensors CS2, it may be determined whether the motor has a phase-to-phase short circuit or a phase-open state.

In addition, the controller 400 is based on the phase current measured by at least one of the first current sensor CS1 and the second current sensor CS2, the first current sensor CS1 and the second current sensor CS2. Gain can be adjusted.

Here, if the magnitude of the phase current measured by at least one of the first current sensor CS1 and the second current sensor CS2 is determined to be an overcurrent equal to or greater than the first reference value, the controller 400 may determine the phase-to-phase short circuit.

In addition, if the magnitude of the phase current measured by at least one of the first current sensor CS1 and the second current sensor CS2 is determined to be a minute current equal to or less than the second reference value, the controller 400 may determine that the phase is open. .

As described above, in the inverter control apparatus according to the embodiment of the present invention, the control unit 400 controls the on/off of each switch (SW1 to SW6) and compares the current of each phase, so that a motor failure (interphase short circuit and phase open) May be determined, and through this, damage to the inverter 200 and the motor 100 caused by a phase-to-phase short circuit and phase opening when the inverter 200 is driven can be prevented in advance.

In addition, if the magnitudes of the phase currents measured by the first and second current sensors CS1 and CS2 are different from each other, the control unit 400 controls the first current sensor CS1 so that the magnitudes of the phase currents are the same. ) And the gain of the second current sensor CS2 can be adjusted.

As described above, in the inverter control apparatus according to an embodiment of the present invention, the controller 400 controls the on/off of each switch SW1 to SW6 and compares the currents of each phase, so that the first current sensor CS1 and the second current The gain of the sensor CS2 can be adjusted, and through this, it is possible to reduce a torque ripple generated in the motor 100 when the inverter 200 is driven.

5 is a table for explaining a method of determining whether a motor is short-circuited between phases and an open phase, and a method of adjusting a gain of a current sensor by a control unit of the inverter control apparatus according to an exemplary embodiment of the present invention. And, FIG. 6 is a flowchart of FIG. 5.

2, 5, and 6, the control unit 400 turns off all of the first to sixth switches SW1 to SW6 (Mode0), and each phase (A, B, C) If it is determined that the phase current does not flow, it is determined that the motor 100 is normal.

In addition, the control unit 400 controls the on/off of the first switch SW1 and the fifth switch SW5 (the remaining switches SW2 to SW4 and SW6 are in an off state) (Mode1), A phase current or B phase When the magnitude of the current is determined to be an overcurrent (OC) that is equal to or greater than the first reference value, it may be determined as a short circuit between the A-phase and B-phase. Here, the overcurrent (OC) introduced into the A phase comes out to the B phase, so that the A phase current becomes (+) overcurrent (OC+) and the B phase current becomes (-) overcurrent (OC-). And, if the magnitude of the A-phase current or B-phase current is determined to be a minute current (0) that is less than or equal to the second reference value (here, 0 is an ideal value and is actually a value close to 0), it can be determined as an A-phase or B-phase open. .

In addition, the control unit 400 controls on/off of the first switch SW1 and the sixth switch SW6 (the remaining switches SW2 to SW5 are in an off state) (Mode2), and the magnitude of the phase A current is first If it is judged as an overcurrent (OC) that is more than the reference value, it can be judged as a short circuit between phase A and phase C. Here, the overcurrent (OC) introduced into the A-phase comes out to the C-phase, and the A-phase current becomes (+) overcurrent (OC+). In addition, if the magnitude of the A-phase current is determined to be a minute current (0) equal to or less than the second reference value, it may be determined as an A-phase or C-phase open.

In addition, the control unit 400 controls the on/off of the second switch SW2 and the sixth switch SW6 (the remaining switches SW1 and SW3 to SW5 are in an off state) (Mode3), and the magnitude of the phase B current is If it is determined that the overcurrent (OC) is greater than or equal to the first reference value, it may be determined as a short circuit between phase B and phase C. Here, here, the overcurrent (OC) introduced into the B phase comes out to the C phase, and the B-phase current becomes a (+) overcurrent (OC+). In addition, when the magnitude of the B-phase current is determined to be a minute current (0) equal to or less than the second reference value, it may be determined as the B-phase or C-phase open.

In addition, when it is determined that the phase-to-phase short circuit or phase-open phase, the controller 400 turns off all of the first to sixth switches SW1 to SW6 (Mode0).

Meanwhile, torque ripple generated from AC power supplied to the motor 100 occurs according to the gain of the current sensor 300.

Hereinafter, the relationship between the gain of the current sensor 300 and the torque ripple will be described with reference to Equations 1 to 3 below.

The A-phase current (ia), B-phase current (ib), and C-phase current (ic) can be calculated according to Equation 1 below.

[Equation 1]

Here, k1 is a gain of the first current sensor CS1, and k2 is a gain of the second current sensor CS2.

When the A-phase current (ia), B-phase current (ib), and C-phase current (ic) calculated by Equation 1 are applied to Equation 2 below, the generated torque Te can be calculated.

[Equation 2]

When the generated torque Te calculated by Equation 2 is applied to Equation 3 below, the torque ripple Tr can be calculated.

[Equation 3]

Referring to Equation 3, when the difference between the gain of the first current sensor CS1 and the gain of the second current sensor CS2 is 0, that is, the gain of the first current sensor CS1 and When the gains of the second current sensor CS2 are the same, it can be seen that the torque ripple Tr is minimized.

The controller 400 controls on/off of the first switch SW1 and the fifth switch SW5 if it is not determined that the phase-to-phase short circuit and the phase-open phase are determined. In addition, if the magnitudes of the phase A and B currents are different, the gains of the first and second current sensors CS1 and CS2 may be adjusted so that the magnitudes of the phase A and B currents are the same.

Specifically, the control unit 400 controls on/off of the first switch SW1 and the fifth switch SW5 (the remaining switches SW2 to SW4 and SW6 are in an off state) (Mode1). Then, the current flowing into the A phase comes out to the B phase, so that the A phase current Ia1 and the B phase current Ib1 have current values of opposite polarities (Ia1=-Ib1).

In addition, the control unit 400 controls on/off of the first switch SW1 and the sixth switch SW6 (the remaining switches SW2 to SW5 are in an off state) (Mode2). Then, the current flowing into the A phase comes out to the C phase, so that the A phase current Ia2 and the C phase current Ic2 have current values of opposite polarities (Ia2=-Ic2). Further, since no current flows through the B phase, the current value of the B phase current Ib2 is zero.

In addition, the control unit 400 controls on/off of the second switch SW2 and the sixth switch SW6 (the remaining switches SW1 and SW3 to SW5 are in an off state) (Mode3). Then, the current flowing into the B phase comes out to the C phase, so that the B phase current Ib3 and the C phase current Ic3 have current values of opposite polarities (Ib3=-Ic3). Further, since no current flows through the A phase, the current value of the A phase current Ia3 is zero.

Under the above-described Mode1 condition, the gains of the first and second current sensors CS1 and CS2 may be adjusted so that the A-phase current Ia1 and the B-phase current Ib1 have the same magnitude.

The gain of the first current sensor CS1 and the gain of the second current sensor CS2 adjusted as described above are the same.

On the other hand, the A-phase current (Ia1) and B-phase current (Ib1) measured by the first and second current sensors, respectively, and the A-phase current (Ia1) and B-phase current (Ib1) flowing in the actual A and B phases. ) May have a difference, so that the magnitudes of the phase A current (Ia1) and the phase B current (Ib1) become the average of the phase A current (Ia1) and the phase B current (Ib1), respectively, the first current sensor CS1 And it is preferable to adjust the gain of the second current sensor CS2.

Through this, it is possible to reduce a torque ripple generated in the motor 100 when the inverter 200 is driven.

Although an embodiment of the present invention has been described above, the spirit of the present invention is not limited to the embodiment presented in the present specification, and those skilled in the art who understand the spirit of the present invention can add components within the scope of the same idea. It will be possible to easily propose other embodiments by changing, deleting, adding, etc., but it will be said that this is also within the scope of the present invention.

100: motor
200: inverter
300: current sensor
400: control unit

Claims (14)

motor;
An inverter including first to sixth switches and converting DC power into AC power and supplying it to the motor;
First and second current sensors respectively measuring phase currents flowing through two phase connections among the three phase connections between the motor and the inverter; And
By controlling the on-off of two switches among the first to sixth switches, it is determined whether the motor has a phase-to-phase short circuit or phase-open based on the phase current measured by at least one of the first and second current sensors, and , Comprising a control unit for adjusting the gain of the first and second current sensors
Inverter control unit.
The method of claim 1,
The control unit
When the magnitude of the phase current measured by at least one of the first and second current sensors is determined to be an overcurrent equal to or greater than a first reference value, the phase-to-phase short circuit is determined.
Inverter control unit.
The method of claim 1,
The control unit
If the magnitude of the phase current measured by at least one of the first and second current sensors is determined to be a minute current equal to or less than a second reference value, the phase is determined to be open.
Inverter control unit.
The method of claim 1,
The control unit
If the magnitudes of the phase currents measured by the first and second current sensors are different from each other, the gains of the first and second current sensors are adjusted so that the magnitudes of the phase currents respectively measured are the same.
Inverter control unit.
The method of claim 1,
The inverter includes first to third arms connected in parallel,
The first arm includes first and fourth switches connected in series, the second arm includes second and fifth switches connected in series, and the third arm includes third and sixth switches connected in series.
Inverter control unit.
The method of claim 5,
The contacts of the first and fourth switches are connected to the A-phase connection between the motor and the inverter, and the contacts of the second and fifth switches are connected to the B-phase connection between the motor and the inverter, and the third and The contact point of the sixth switch is connected to the C-phase connection between the motor and the inverter.
Inverter control unit.
The method of claim 6,
The first current sensor measures a phase A current flowing through the phase A connection, and the second current sensor measures a phase B current flowing through the phase B connection.
Inverter control unit.
The method of claim 7,
The control unit
The first and fifth switches are controlled to be turned on and off, and if the magnitude of the phase A current or the phase B current is determined to be an overcurrent equal to or greater than a first reference value, it is determined as a short circuit between the phases A and B, and the phase A current Or, if the magnitude of the B phase current is determined to be a minute current equal to or less than the second reference value, the A phase or B phase is determined to be open.
Inverter control unit.
The method of claim 7,
The control unit
The first and sixth switches are controlled to be turned on and off, and if the magnitude of the A-phase current is determined to be an overcurrent equal to or greater than a first reference value, it is determined as a short circuit between the A-phase and C-phase, and the magnitude of the A-phase current is second If it is judged as a minute current below the reference value, it is determined as the A phase or C phase open.
Inverter control unit.
The method of claim 7,
The control unit
The second and sixth switches are controlled to be turned on and off, and if the magnitude of the B-phase current is determined to be an overcurrent equal to or greater than a first reference value, it is determined as a short circuit between the B-phase and C-phase, and the magnitude of the B-phase current is second If it is determined as a minute current below the reference value, it is determined as the B phase or C phase open.
Inverter control unit.
The method of claim 7,
The control unit
Controls the on-off of the first and fifth switches, and if the magnitudes of the A-phase current and the B-phase current are different, the first and second current sensors have the same magnitudes of the A-phase current and the B-phase current. Gain-tuning
Inverter control unit.
The method of claim 7,
The control unit
Turning on any one of the first to sixth switches and turning off the remaining switches to determine whether any one of the remaining switches has failed.
Inverter control unit.
The method of claim 12,
The control unit
To determine whether a switch connected to the same arm as the turned-on switch has failed
Inverter control unit.
The method of claim 12,
The control unit
If a dark current flows through the turned-on switch, it is determined that the switch connected to the same arm has failed.
Inverter control unit.

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