KR20200005281A - System and method for discharging direct current link capacitor of inverter for driving motor - Google Patents

Abstract

A DC link capacitor discharge system of an inverter for driving a motor includes: a DC link capacitor forming DC link voltage on both terminals thereof by charging; an inverter having an input terminal to which the DC link voltage is applied, a plurality of switching devices, and an output terminal which outputs AC voltage formed by converting the DC link voltage by short/open control of the plurality of switching devices; a motor which operates by using AC voltage outputted from the inverter; a discharge resistance and a switch connected together in series on a location where the DC link capacitor and a current loop can be formed; a first discharging control unit controlling short/open of the switching device to adjust AC voltage provided to the motor to consume charging power of the DC link capacitor with the motor when forced discharging on the DC link capacitor is required; and a second discharging control unit shortening the switch to form a current loop between the discharge resistance and the DC link capacitor when forced discharging on the DC link capacitor is required and the inverter and the motor are electrically open. According to the present invention, it is possible to quickly lower DC link voltage of a high voltage DC link capacitor so that a risk of exposure to high voltage by car accident can be significantly reduced.

Description

DC Link Capacitor Discharge System and Method of Motor Drive Inverter {SYSTEM AND METHOD FOR DISCHARGING DIRECT CURRENT LINK CAPACITOR OF INVERTER FOR DRIVING MOTOR}

The present invention relates to a system and method for discharging a DC link capacitor of an inverter for driving a motor. More specifically, the present invention relates to a DC link capacitor quickly so as to satisfy safety regulations even when a forced discharge of a DC link capacitor using a motor is impossible. The present invention relates to a DC link capacitor discharge system and method of an inverter for driving a motor capable of discharging a voltage.

As the problems of global warming and environmental pollution become serious, research and development on eco-friendly vehicles that can reduce the environmental pollution as much as possible in the automotive industry is being actively conducted, and the market is gradually expanding.

As an eco-friendly vehicle, electric vehicles, hybrid vehicles, and plug-in hybrid vehicles that use motors that generate driving power by using electric energy instead of engines that burn existing fossil fuels to generate driving power are being released worldwide. Eco-friendly vehicles using such electric energy include an inverter for converting the stored direct current electric energy into a plurality of phases (normally three phases) of alternating current electric energy for driving a motor. The input terminal of the inverter is provided with a high-capacity DC link capacitor for applying a predetermined voltage to the direct current electrical energy provided from the energy storage device, etc., the output terminal of the inverter has a plurality of alternating voltages of the DC link capacitor Is output.

Since a DC link capacitor is provided at the input terminal of the motor driving inverter to maintain a high voltage by charging, even when the electrical connection between the inverters in the energy storage device is cut off, the input terminal of the inverter is charged at a high voltage state by charging the DC link capacitor. Is maintained so that a safety accident can occur.

For example, when a driver or a mechanic touches a high voltage line for the purpose of vehicle maintenance after a vehicle key off, an electric shock may occur due to the high voltage charged in the DC link capacitor. As another example, when a high impact accident occurs such that an airbag is deployed, when the high voltage connector connected to the inverter is disconnected, when the high voltage charged in the DC link capacitor contacts the vehicle body or the other surface, an electric shock may occur. .

In order to prevent such a safety accident, laws are provided in each country for the rapid discharge of the DC link capacitor after the vehicle key-off or after the vehicle accident occurs. In order to meet these national regulations, not only the provision of a discharge resistor for consuming the charging power of the DC link capacitor but also a method of forcibly generating energy by using the heat of the motor through inefficient operation of the motor is adopted. It is becoming. In other words, there is a time limit for simply consuming the charging energy of the DC link capacitor through the discharge resistor, and to overcome this limitation, a method of forcibly consuming energy by using a motor is adopted.

However, the method of forcibly consuming energy by using a motor cannot be applied when the connector between the inverter and the motor is disconnected due to an accident. Therefore, the voltage of the DC link capacitor is discharged to the desired procedure within the discharge time required by law. There is a problem that can not be.

The matters described as the background art are only for the purpose of improving the understanding of the background of the present invention, and should not be taken as acknowledging that they correspond to the related art already known to those skilled in the art.

KR 10-2008-0014395 A KR 10-2012-0053037 A

Accordingly, the present invention provides a DC link capacitor discharge system and method for an inverter for driving a motor capable of quickly discharging a DC link capacitor so as to satisfy a safety law-related specification even when a forced discharge of the DC link capacitor using a motor is impossible. The technical problem to be solved to provide.

The present invention as a means for solving the above technical problem,

A direct current link capacitor, which forms a direct current link voltage at both ends thereof by charging;

An inverter having an input terminal to which the DC link voltage is applied, a plurality of switching elements, and an output terminal for outputting an AC voltage formed by converting the DC link voltage by short-circuit / open control of the plurality of switching elements;

A motor driven by using an AC voltage output from the inverter;

A discharge resistor and a switch connected in series with each other to form a current loop with the DC link capacitor;

A first discharge controller configured to control short-circuit / opening of the switching element to consume charging power of the DC link capacitor by the motor when a forced discharge of the DC link capacitor is required; And

A second discharge controller configured to form a current loop between the discharge resistor and the DC link capacitor by shorting the switch when a forced discharge of the DC link capacitor is required and the inverter and the motor are electrically open;

It provides a DC link capacitor discharge system of the inverter for driving a motor.

In one embodiment of the present invention, the first discharge control unit may control the switching elements so that the motor drives without outputting torque.

In one embodiment of the present invention, the first discharge control unit or the second discharge control unit, the DC link capacitor based on the airbag deployment signal provided by the airbag system of the vehicle and the relay off signal provided by the battery management system of the vehicle. Forced discharge of the to determine whether the request, the relay off signal may be provided in the energy storage device for providing a power source for forming the DC link voltage of the DC link capacitor.

In one embodiment of the present disclosure, the first discharge control unit or the second discharge control unit may cause the second discharge control unit to operate when the magnitude of the output current of the inverter is smaller than the preset reference current.

In one embodiment of the present invention, one end of the switch and the discharge resistor and the series connected in series may be connected to the inverter output terminal and the other end is connected to the capacitor.

In one embodiment of the present invention, the first discharge controller is electrically connected to the input terminal of the inverter and the discharge resistor connected in series with one end of the switch when the output current of the inverter is smaller than the preset reference current. The switching element can be controlled to be.

As another means for solving the above technical problem, the present invention,

Determining whether a forced discharge of the DC link capacitor including the switching element and connected to form a DC link voltage at an input terminal of the inverter converting the DC power input by the short / opening of the switching element into AC power and outputting the AC power;

A first discharge control step of controlling a switching element in the inverter so as to discharge the DC link capacitor by driving a motor connected to an output terminal of the inverter when a forced discharge of the DC link capacitor is required;

Determining a connection state between the inverter and the motor;

A second discharge control step of forcibly discharging the DC link capacitor by the discharge resistance by connecting a discharge resistor to the DC link capacitor when the inverter and the motor are not connected;

It provides a DC link capacitor discharge method of the inverter for driving a motor.

In one embodiment of the present invention, the step of determining whether the forced discharge, the airbag deployment signal provided by the airbag system of the vehicle and the relay off signal provided by the battery management system of the vehicle determines that the forced discharge is required The relay off signal may be provided in an energy storage device that provides a power source for forming a DC link voltage of the DC link capacitor.

In one embodiment of the present invention, the first discharge control step may control the switching elements in the inverter to drive the motor does not output torque.

In an embodiment of the present disclosure, the determining of the connection state may determine that the inverter and the motor are not connected when the magnitude of the output current of the inverter is smaller than the preset reference current.

The DC link capacitor discharge system and method of the motor driving inverter can rapidly lower the DC link voltage of the high voltage DC link capacitor, thereby significantly reducing the risk of high voltage exposure in a vehicle accident or the like.

In particular, the DC link capacitor discharging system and method of the motor driving inverter may not only rapidly lower the DC link voltage of the DC link capacitor through zero torque control of the motor, but also the connector of the inverter and the motor may be disconnected. Likewise, even when a forced discharge using a motor is impossible, additional discharge may be caused by the discharge resistor by allowing the additional discharge resistor and the DC link capacitor to form a current loop. Accordingly, the DC link capacitor discharge system and method of the motor driving inverter enables a voltage level to be reduced to a reference level or less within a reference time required in an emergency situation such as an accident required by law.

1 is a block diagram of a DC link capacitor discharge system of a motor drive inverter according to an embodiment of the present invention.
FIG. 2 is a circuit diagram illustrating an equivalent circuit of an inverter formed during second discharge control in a DC link capacitor discharge system of a motor driving inverter according to an embodiment of the present invention.
3 is a flowchart illustrating a DC link capacitor discharge method of the motor driving inverter according to the embodiment of the present invention.
4 is a timing diagram showing a control operation by a DC link capacitor discharge system and method of a motor driving inverter according to an embodiment of the present invention with time.

Hereinafter, a DC link capacitor discharge system and method of a motor driving inverter according to various embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

1 is a block diagram of a DC link capacitor discharge system of a motor drive inverter according to an embodiment of the present invention.

Referring to FIG. 1, a DC link capacitor discharge system of a motor driving inverter according to an embodiment of the present invention includes a DC link capacitor C, an inverter 10, a motor 20, and a discharge resistor R2. ), A switch S1, and a first discharge control unit 110 and a second discharge control unit 120.

The DC link capacitor C may be charged by DC power provided from an energy storage device such as a battery or other form of DC power to form a DC link voltage V _DC at an input terminal of the inverter 10.

Inverter 10 includes a plurality of switching elements (Q1 to Q6), and receiving the DC link voltage (V _DC) input terminal and a plurality of switching elements DC link voltage (V _DC) by the open / short of (Q1 to Q6) It may have an output terminal for outputting the AC voltage (AC current) formed by converting the. In FIG. 1, two terminals to which the inverter 10 and the DC link capacitor C are connected are input terminals of the inverter 10, and three terminals to which the inverter 10 and the motor 20 are connected are output terminals of the inverter 10. Can be.

The inverter 10 shown in FIG. 1 is an example of an inverter that outputs three-phase AC power including u phase, v phase, and w phase. In the inverter 10, in the plurality of switching elements Q1 to Q6, two switching elements that generate power of each phase form one leg 11, 12, 13. For example, the alternating current power of u phase is generated by the switching elements Q1 and Q4 included in the first leg 11, and the alternating current power of the v phase is included in the switching elements Q2, included in the second leg 12. AC power generated by Q5) may be generated by switching elements Q3 and Q6 included in the third leg 13.

Typically, the inverter 10 receives a torque command corresponding to a torque that the motor 20 wants to output, receives feedback of a drive current provided to the motor 20 and a rotor position of the motor 20, and the like. The plurality of switching elements Q1 to Q6 may be controlled by PWM control so that 20 may output a torque corresponding to the torque command. The inverter 10 control method for driving the motor corresponds to a known technique in the art and is not particularly related to the main technical idea of the present invention, so a detailed description thereof will be omitted.

The motor 20 may be driven by receiving the AC power converted by the inverter 10. For example, the motor 20 may be implemented as an embedded permanent magnet synchronous motor, which is a three-phase AC motor.

The discharge resistor R2 and the switch S1 may be connected in series to each other and may be connected to a position where a DC link capacitor C and a current loop or a DC link capacitor C may be connected in parallel. In the example of FIG. 1, the discharge resistor R2 and the switch S1 connected in series are connected to a u-phase output terminal of which one end of the series connection structure is one of the output terminals of the inverter 10 and the other end of the DC link capacitor C. Is connected to one end. In this structure, when the switching element Q1 of the inverter 10 is short-circuited, one end of the discharge resistor R2 and the switch S1 connected in series are connected to the other end of the DC link capacitor C, so that the DC link capacitor C- A current loop connected to the discharge resistor (R2)-> switch (S1)-> DC link capacitor (C) can be formed. After the current loop is formed, if the switch S1 is shorted, current flows through the current loop. In FIG. 1, an example in which the series connection structure of the discharge resistor R2 and the switch S1 is connected to the u-phase output terminal of the inverter 10 is illustrated, but in another example, the discharge resistor R2 and the switch S1 are connected in series. The connection structure may be connected to the v-phase or w-phase output terminal of the inverter 10.

FIG. 1 illustrates an example in which one end of the discharge resistor R2 and the switch S1 connected in series are connected to one of the output terminals of the inverter 10, but as another example, the discharge resistor R2 and the switch S1 connected in series to each other. One end of) may be commonly connected to two or more of the output terminals of the inverter 10. As another example, the DC link capacitor C may be directly connected at both ends of one end and the other end of the discharge resistor R2 and the switch S1 connected in series. This example can form a current loop with the DC link capacitor C even if the short / open control of the switching elements Q1 to Q6 of the inverter 10 is not performed.

When the forced discharge of the DC link capacitor is required, the first discharge control unit 110 may control the short circuit / opening of the switching element in the inverter 10 so that the discharge may be performed by the motor 20. For example, the first discharge control unit 110 performs the zero torque control so that the q (Quadrature) axis current of the motor 20 is 0 and the d (Direct) current is maximized. The short circuit / opening of the switching element in the inside can be controlled. When the q-axis current is 0 When the motor 20 is driven by using zero torque control in which the torque does not occur in the motor regardless of the magnitude of the d-axis current, the motor 20 does not generate torque and provides the received energy. Will be lost as heat. Therefore, the DC link capacitor C of the input terminal of the inverter 10 can be quickly discharged.

Since the forced discharge control by the first discharge control unit 110 utilizes the motor 20, when the connector connecting the inverter 10 and the motor 20 is removed by a collision accident or the like, the first discharge control unit 110 is removed. ), Forced discharge control becomes impossible. In consideration of this point, the present invention includes a second discharge control unit 120.

When the forced discharge of the DC link capacitor is required and the forced discharge control by the first discharge controller 110 is impossible, the second discharge controller 120 opens the switch S1 connected in series with the discharge resistor R2 in an open state. Switched to the short-circuit state to charge the DC link capacitor (C) by allowing a current to flow in the current loop from DC link capacitor (C)-> discharge resistor (R2)-> switch (S1)-> DC link capacitor (C). Power may be consumed through heat generation of the discharge resistor R2.

Of course, when the discharge resistor R2 is connected to the output terminal of the inverter 10, the first discharge controller 110 controls the switching elements Q1 to Q6 of the inverter 10 to control the DC link capacitor C and the discharge resistor. A current path between (R2) must be formed. An example is shown in FIG. 2.

In addition, in FIG. 1, the first discharge controller 110 receives a signal from the airbag system 30 and the battery management system 40 to determine whether a forced discharge of the DC link capacitor C is required, Although it is shown as determining whether the second discharge control unit 120 operates, this is only an example, and the second discharge control unit 120 may directly receive a signal from the airbag system 30 and the battery management system 40. . In addition, in FIG. 1, the first discharge control unit 110 receives a value for detecting the output current of the inverter 10 to determine whether the second discharge control unit 120 operates, but this is also merely an example. The second discharge controller 120 may determine whether to operate itself by receiving a value of detecting the output current of the inverter 10.

FIG. 2 is a circuit diagram showing an equivalent circuit of an inverter formed during the second discharge control in the DC link capacitor discharge system of the motor drive inverter according to the embodiment of the present invention.

When it is determined that the forced discharge by the motor 20 is impossible, the first discharge control unit 110 short-circuits the upper switching elements Q1, Q3, Q5 of each leg 11, 12, 13 and each leg 11, The lower switching elements Q2, Q6, and Q4 of 12 and 13 may be opened. In addition, the second discharge controller 120 may short the switch S1 to complete a current loop in which an electrical connection relationship as shown in FIG. 2 is formed. For reference, FIG. 2 illustrates a circuit structure in which the discharge resistor R2 is commonly connected to each of a plurality of output terminals constituting the output terminal of the inverter 10.

Meanwhile, determining that the forced discharge control is required may be an airbag deployment signal provided by the in-vehicle airbag system 30 or a main relay blocking signal provided by the battery management system (BMS) 40. have.

For example, the airbag deployment in the airbag system 30 is a situation in which a shock or shock is applied to the vehicle, so that the high-voltage state is externally caused by a vehicle accident by forcibly discharging the DC link capacitor C charged at a high voltage as quickly as possible. To prevent exposure.

In addition, the BMS 40 also operates to shut off the main relay connected to the high voltage battery which becomes the driving power of the vehicle when the vehicle is keyed off or a predetermined shock is applied to the vehicle. The high voltage battery is a power source for forming a DC link voltage formed at the input terminal of the inverter described above. When the main relay blocking signal is generated in the BMS 40, a rapid forced discharge may be performed to prevent a high voltage exposure situation in advance.

In addition, in order to determine that forced discharge by the motor 20 is impossible, the current of the line connecting the inverter 10 and the motor 20, that is, the magnitude of the output current of the inverter 10 may be detected. When the connector connecting the inverter 10 and the motor 20 is removed by an impact or the like, the output current of the inverter 10 has a magnitude close to zero. Although not shown, since the current sensor is already installed at the output end of the inverter 10 to control the motor 20, when the inverter output current detected by the current sensor decreases below a predetermined size, the inverter 10 and the motor ( It is determined that the connection between the 20 is disconnected and the switch S2 uses the second discharge control unit 120 instead of the forced discharge using the motor 20 so that the discharge resistor R2 consumes the charging power of the DC link capacitor C. ) Can be shorted.

In FIG. 1, 'R1' is a discharge resistance that can be normally installed. The first discharge control unit 110 or the second discharge control unit 120 does not operate for forced discharge when a normal vehicle is turned off or when a vehicle connector is removed. It is provided for the discharge of the DC link capacitor (C) in the state. The resistance value of the discharge resistor R1 may be determined so as to satisfy the discharge reference time at the time of the normal keyoff provided in the vehicle safety regulations.

The present invention also provides a DC link capacitor discharge method of a drive inverter using a system as shown in FIG.

3 is a flowchart illustrating a DC link capacitor discharge method of a motor driving inverter according to an embodiment of the present invention, and FIG. 4 is a DC link capacitor discharge system and method of a motor driving inverter according to an embodiment of the present invention. Is a timing diagram showing the control operation by time.

Referring to FIG. 3, the DC link capacitor discharge method of the motor driving inverter according to the exemplary embodiment of the present disclosure may be started from the step of determining whether the forced discharge is started. The step of determining whether the forced discharge is started may include determining whether an airbag deployment signal has been generated in the vehicle airbag system 30 (S11) and an input terminal of the inverter 10 by the battery management system BMS of the vehicle. It may include the step (S12) of checking whether the relay (main relay) connected to the output terminal of the power supply (battery) for providing power to the power off. Examples of the signal applied to these steps S11 and S12 are shown by reference numerals '51' and '52' in FIG.

That is, as shown in FIG. 4, when the airbag deployment signal is generated by the airbag system 30 at the 'Ta' time point, and then the main relay off signal 52 is generated by the BMS 40, the first discharge control unit ( The controller 110 may determine that the forced discharge is required and perform the first discharge control using the motor 20 (S13). The start of the step S13 of performing the first discharge control is shown by reference numeral 53 in FIG. 4. As described above, step S13 may be performed by controlling the switching elements Q1 to Q6 of the inverter 10 to control the zero torque of the motor 20.

Simultaneously with step S13, the first discharge controller 110 may perform a step S14 of comparing the magnitudes Iu, Iv, and Iw of the inverter output current with a preset reference current Ith. This step S14 is shown at 54 in reference to FIG. 4. In FIG. 4, the inverter output current detection signal indicates a HIGH state when the magnitudes (Iu, Iv, and Iw) of the inverter output current are larger than the preset reference current Ith, that is, between the inverter 10 and the motor 20. Indicates that the connector is properly connected.

As a result of the comparison in step S14, when the magnitudes Iu, Iv, and Iw of the inverter output current are larger than the preset reference current Ith, the state of the switch S1 is opened as shown by reference numeral 55 in FIG. It can be maintained at (S16).

Through this control process, the voltage of the DC link capacitor C decreases below the desired voltage level (set at, for example, 60V in FIG. 4) in the legislation immediately after the first discharge control is started. This allows the voltage to fall below the required voltage level before reaching the reference time (Tref) required by law. This feature of voltage level reduction is shown at 56 in reference to FIG. 4.

On the other hand, if the magnitude (Iu, Iv, Iw) of the inverter output current is less than or equal to the preset reference current (Ith) as a result of the comparison of step S14, the inverter output current detection signal as shown by reference numeral '57' of FIG. Maintains a LOW state, and in this case, the first discharge control unit 110 may start the operation of the second discharge control unit 120. That is, in one embodiment of the present invention, when the magnitude (Iu, Iv, Iw) of the inverter output current is less than or equal to the preset reference current (Ith) between the inverter 10 and the motor 20 due to the impact of the vehicle. It can be determined that the connector of is disconnected and use another discharge means that can replace the forced discharge using the motor 20.

If the second discharge control unit 120 is not provided, the DC link capacitor is generated only by the heating of the normal discharge resistor R1 connected in parallel to the DC link capacitor C without the forced discharge using the motor 20. It must consume the charging power of (C). This case is indicated by the reference numeral '58' in FIG. As described above, the discharge resistor R1 is a resistor whose resistance value is designed so that a relatively slow discharge is made in accordance with a normal key-off or maintenance situation, not an emergency situation requiring forced discharge. The voltage of C) cannot be reduced below the required voltage level (for example, 60 V) within the reference time Tref in the emergency situation required by law.

In one embodiment of the present invention, when it is determined that the connector between the inverter 10 and the motor 20 is disconnected, the second discharge control unit 120 is operated to further discharge the discharge resistor R2 and the DC link capacitor C. By forming a current loop therebetween, it is possible to additionally consume the charging power in the DC link capacitor (C). That is, the second discharge controller 120 short-circuits the switch S1 connected to the discharge resistor R2, and the first discharge controller 110 short-circuits the switching elements Q1 to Q6 in the inverter 10 as necessary. By controlling the open state to form a current loop between the discharge resistor (R2) and the DC link capacitor (C) it can be made to discharge the DC link capacitor (C) by the heat generated by the discharge resistor (R2) (S15). ).

This is indicated by reference numerals '59' and '60' in FIG. When the discharge control is started by the first discharge control unit 110 (53) and at the same time the magnitudes Iu, Iv, and Iw of the inverter output current are equal to or smaller than the preset reference current Ith (57), the second The short-circuit control of the switch S1 is performed by the discharge control unit 120 (59), thereby lowering the voltage of the DC link capacitor C below the voltage level required before the reference time Tref required by the law passes. Let's go.

As described above, various embodiments of the present invention can rapidly lower the DC link voltage of the DC link capacitor C having a high voltage, thereby significantly reducing the risk of high voltage exposure in a vehicle accident or the like. In particular, various embodiments of the present invention can not only rapidly lower the DC link voltage of the DC link capacitor C through the zero torque control of the motor 20, but also the connectors of the inverter 10 and the motor 20. Even if the forced discharge using the motor 20 is impossible, such as is separated, the additional discharge resistor (R2) and the direct current link capacitor (C) forms a current loop to be further discharged by the discharge resistor (R2) can do. Accordingly, it is possible to reduce the voltage level below the reference level within the reference time required in an emergency situation such as an accident required by law.

While shown and described in connection with specific embodiments of the present invention, it is understood that the present invention can be variously modified and changed without departing from the technical spirit of the present invention provided by the claims below. It will be apparent to those of ordinary skill in the art.

10: Inverter 11, 12, 13: Leg
20: motor 30: airbag system
40: battery management system 110: first discharge control unit
120: second discharge control unit C: DC link capacitor
Q1-Q6: switching element R1, R2: discharge resistance
S1: switch V _DC : DC link voltage

Claims (10)

A direct current link capacitor, which forms a direct current link voltage at both ends thereof by charging;
An inverter having an input terminal to which the DC link voltage is applied, a plurality of switching elements, and an output terminal for outputting an AC voltage formed by converting the DC link voltage by short-circuit / open control of the plurality of switching elements;
A motor driven by using an AC voltage output from the inverter;
A discharge resistor and a switch connected in series with each other to form a current loop with the DC link capacitor;
A first discharge controller configured to control short-circuit / opening of the switching element to consume charging power of the DC link capacitor by the motor when a forced discharge of the DC link capacitor is required; And
A second discharge controller configured to form a current loop between the discharge resistor and the DC link capacitor by shorting the switch when a forced discharge of the DC link capacitor is required and the inverter and the motor are electrically open;
DC link capacitor discharge system of the inverter for driving a motor. The method according to claim 1,
The first discharge control unit is a DC link capacitor discharge system of the motor drive inverter, characterized in that for controlling the switching elements to drive the motor does not output torque. The method according to claim 1,
The first discharge control unit or the second discharge control unit determines whether the forced discharge of the DC link capacitor is required based on the airbag deployment signal provided by the airbag system of the vehicle and the relay off signal provided by the battery management system of the vehicle. And the relay off signal is provided in an energy storage device for providing a power source for forming a DC link voltage of the DC link capacitor. The method according to claim 1,
The first discharge control unit or the second discharge control unit, when the magnitude of the output current of the inverter is smaller than the magnitude of the predetermined reference current to operate the second discharge control unit, characterized in that the direct current link of the motor drive inverter Capacitor discharge system. The method according to claim 1,
DC discharge capacitor discharge system of the motor drive inverter, characterized in that one end of the switch connected in series with the discharge resistor connected to the inverter output terminal and the other end is connected to the capacitor. The method according to claim 5,
When the magnitude of the output current of the inverter is smaller than the preset reference current, the first discharge controller controls the switching element such that the input terminal of the inverter and the discharge resistor connected in series with one another of the switch are electrically connected. A DC link capacitor discharge system of a motor drive inverter. Determining whether a forced discharge of the DC link capacitor including the switching element is connected to form a DC link voltage at an input terminal of the inverter converting the DC power input by the short / opening of the switching element into AC power and outputting the AC power;
A first discharge control step of controlling a switching element in the inverter so as to discharge the DC link capacitor by driving a motor connected to an output terminal of the inverter when a forced discharge of the DC link capacitor is required;
Determining a connection state between the inverter and the motor;
A second discharge control step of connecting the discharge resistor to the DC link capacitor to force discharge the DC link capacitor by the discharge resistor when the inverter and the motor are not connected;
DC link capacitor discharge method of the inverter for driving a motor. The method according to claim 7,
The determining of the forced discharge may include determining that the forced discharge is required when the airbag deployment signal provided by the vehicle airbag system and the relay off signal provided by the battery management system of the vehicle are generated. A method for discharging a DC link capacitor of an inverter for driving a motor, characterized in that the energy storage device provides a power supply for forming a DC link voltage of the link capacitor. The method according to claim 7,
The first discharge control step, the DC link capacitor discharge method of the motor drive inverter, characterized in that for controlling the switching elements in the inverter to drive the motor does not output torque. The method according to claim 7,
The determining of the connection state may include determining that the inverter and the motor are not connected when the output current of the inverter is smaller than a preset reference current. Discharge method.

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