KR101770987B1 - Inverter fault diagnosis apparatus and the method thereof - Google Patents

Abstract

The present invention is to rapidly and precisely find a position of a fault of a three-phase inverter used for a power control system, etc., at a low cost without using an expensive gate driver, thereby improving reliability of the power control system, etc., and reducing time and cost for maintenance. To this end accordingly, the present invention can use stationary coordinates d-axis current (lds), stationary coordinates q-axis current (lqs), and a pager of modulation indices of each phase (Mla, Mlb, Mlc), which can be calculated from a phase voltage and a phase current of an inverter, to determine an opening fault in a discharging mode, an opening fault in a charging mode, an opening fault in a standby mode, and a short circuit in all modes and to determine at which switch module a fault has occurred.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inverter fault diagnosis apparatus,

The present invention relates to an apparatus and method for diagnosing an inverter fault in which the type of fault and the fault location can be quickly identified and maintenance can be performed in the event of an inverter failure.

Recently, as the installation of an energy storage system (Energy Storage System) is increasing, the use of a power conditioning system for use in an energy storage system is also increasing. Accordingly, much efforts are being made to improve reliability and reduce maintenance time through rapid accident handling in case of power control system failure.

Three-phase inverters are also used for motor control and uninterruptible power systems (UPS) for emergency power sources, but they are also a key component in power control systems for energy storage systems. However, it is not easy to identify the exact fault location when a fault occurs due to voltage and / or current stress in a switch module constituting a 3-phase inverter. If such a fault can not be resolved quickly, It can lead to accidents. Therefore, it is very important to find fault location quickly and accurately when a three-phase inverter fails.

In some cases, a gate driver that provides information on where a failure has occurred in the switch module constituting the three-phase inverter is used, but such a gate driver is expensive and thus it is difficult to apply it to an actual system.

Thus, there is a demand for a method capable of diagnosing a failure of a three-phase inverter quickly and inexpensively without using an expensive gate driver.

It is an object of the present invention to quickly and accurately locate the fault location of a three-phase inverter used in a power control system and the like inexpensively without using an expensive gate driver, thereby improving the reliability of a power control system, It saves time and money.

(Va, Vb, Vc) and phase currents (Ia, Ib, Ic) of a three-phase inverter connected to a power system, A detecting unit for detecting the signal; And the rotational coordinate d-axis current Ide is greater than the first threshold value and the absolute value of the sum of the phasor values of the three-phase currents Ia, Ib, Ic is greater than the second threshold value (Ids) and the stationary coordinate q-axis current (Iqs) are used to determine the failure position, and the absolute value of the rotational coordinate d-axis current (Ide) is smaller than the first threshold value, If the absolute value of the sum of phasor values of the modulation indexes (MIa, MIb, MIc) is larger than the third threshold value, it is determined that the open failure is in the standby mode, and the pseudo modulation index (MIa, MIb, MIc) And a fault location determination unit for determining the fault location of the inverter.

(MI) is higher than the a-phase voltage (Va) and the b-phase MI (MIb) is higher than the b-phase voltage (Vb) in the case where the open- Phase MI (MIa) is higher than the a-phase voltage (Va) and the b-phase (MI) is higher than the a-phase voltage Phase MI (MIa) is higher than the b-phase voltage (Vb) and the c-phase MI (MIc) is above the c-phase voltage (Vc) Phase MI (MIb) is higher than the b-phase voltage (Vb) and the c-phase MI (MIc) is higher than the c-phase voltage (Vc) It can be judged.

In the fault diagnosis apparatus of the inverter, when the absolute values of the rotational coordinate d axis current Ide are larger than the first threshold value and when the magnitudes of the phase currents Ia, Ib, Ic are all smaller than the fourth threshold value, It is possible to judge the failure position by using the pause of the stop coordinate d axis current Ids and the stop coordinate q axis current Iqs.

In the fault diagnosis apparatus of the inverter, if the rotational coordinate d axis current Ide has a positive value, it is determined that the discharge mode is selected. If the stop coordinate d axis current Ids is above the reference value Ids * Axis current Ids is smaller than the value of the stop coordinate q-axis current Iqs and the stop coordinate d-axis current Ids is judged to be a failure of the a-phase switch module and the stop coordinate d-axis current Ids is above the reference value Ids * If the magnitude of the current Ids is greater than the magnitude of the stop coordinate q-axis current Iqs, it is determined that the b-phase switch module is faulty. If the stop coordinate d-axis current Ids is more advanced than the reference value Ids * If the axis current Iqs is above the reference value Iqs *, it can be judged that the c-phase switch module is faulty.

In the fault diagnosis apparatus of the inverter, if the rotational coordinate d axis current Ide has a negative value, the charge mode is determined. If the magnitude of the stationary coordinate d axis current Ids is smaller than the fifth threshold value from the reference value Ids * And when the stop coordinate d axis current Ids is above the reference value Ids * and the stop coordinate q axis current Iqs is more advanced than the reference value Iqs * If the stop coordinate d axis current Ids is higher than the reference value Ids * and the stop coordinate q axis current Iqs is above the reference value Iqs * It can be judged as a failure.

If at least one of the magnitudes of the phase currents is larger than the fourth threshold value in the fault diagnosis apparatus of the inverter, it is determined that there is a short circuit fault, and the pause of the stop coordinate d axis current Ids and the stationary coordinate q axis current Iqs Can be used to determine the fault location.

When the stop coordinate d axis current Ids is in the range of 120 to 240 degrees and the stationary coordinate q axis current Iqs is in the range of 240 to 360 degrees based on the a phase voltage Va in the fault diagnosis apparatus of the inverter, If it is determined that the phase switch module is faulty and the stop coordinate d axis current Ids is in the range of 120 to 240 degrees and the stop coordinate q axis current Iqs is in the range of 0 to 120 degrees based on the a phase voltage Va, (Ids) is in the range of 0 to 120 degrees and the stop coordinate q-axis current (Iqs) is in the range of 0 to 120 degrees based on the a-phase voltage (Va) It can be judged that the c-phase switch module has failed.

(Va, Vb, Vc) and phase currents (Ia, Ib, Ic) of an inverter are measured by a fault diagnosis apparatus of a three-phase inverter connected to a power system. A first step of detecting the first step; A second step of comparing an absolute value of the rotational coordinate d axis current Ide with a first threshold value; In the second step, when the absolute value of the rotational coordinate d axis current Ide is greater than the first threshold value and the absolute value of the sum of the phasor sums of the three-phase currents Ia, Ib, Ic is greater than the second threshold value, Axis current Ids and the stationary coordinate q-axis current Iqs are used to determine the failure position, and in the second step, the absolute value of the rotational coordinate d-axis current Ide (MIa, MIb, MIc) of the three phases is determined to be an open failure in the standby mode when the absolute value of the sum of phasor values of the modulation indexes (MIa, MIb, MIc) of the three phases smaller than the first threshold value is larger than the third threshold value. And a third step of determining a fault location using a phaser of the inverter.

 (MIa) is higher than the a-phase voltage (Va) and the b-phase MI (MIb) is higher than the a-phase voltage (Va) when the open failure in the standby mode is determined in the third step phase MI (MIa) is higher than the b-phase voltage (Vb) and the a-phase MI (MIa) is higher than the c-phase voltage (Vc) Phase switch module is judged to be faulty when the b-phase MI (MIb) is higher than the b-phase voltage (Vb) and the c-phase MI (MIc) is above the c-phase voltage (Vc) When MI (MIa) is above the a-phase voltage Va and the b-phase MI (MIb) is higher than the b-phase voltage Vb and the c-phase MI (MIc) It can be determined that the phase switch module has failed.

In the fault diagnosis method of the inverter, it is determined that an open fault occurs when the magnitude of each of the phase currents (Ia, Ib, Ic) is less than the fourth threshold value in the case where it is determined that the fault occurs in the operation mode in the third step, The fault position can be determined using the pseudo-coordinate d axis current Ids and the phase coordinate q axis current Iqs.

In the fault diagnosis method of the inverter, if the rotating coordinate d-axis current Ide has a positive value, it is determined that the discharge mode is selected. If the stop coordinate d-axis current Ids is above the reference value Ids * It is determined that the a-phase switch module is in failure when the magnitude of the current Ids is smaller than the magnitude of the stationary coordinate q-axis current Iqs, and when the stop coordinate d-axis current Ids is above the reference value Ids * If the magnitude of the axial current Ids is greater than the magnitude of the stop coordinate q-axis current Iqs, it is determined that the b-phase switch module has failed. If the stop coordinate d-axis current Ids is more advanced than the reference value Ids * If the q-axis current (Iqs) is above the reference value (Iqs *), it can be judged that the c-phase switch module has failed.

In the fault diagnosis method of the inverter, if the rotating coordinate d axis current Ide has a negative value, the charging mode is determined, and if the magnitude of the stationary coordinate d axis current Ids is greater than the fifth threshold value Ids * Phase switch module is judged to be a failure, and when the stop coordinate d-axis current Ids is above the reference value Ids * and the stop coordinate q-axis current Iqs is higher than the reference value Iqs * Axis current Iqs is higher than the reference value Ids * and the stationary coordinate q-axis current Iqs is above the reference value Iqs *, it is determined that the b- As shown in FIG.

Wherein when the at least one of the magnitudes of the phase currents is greater than the fourth threshold value in the case where it is determined that the fault has occurred in the operation mode in the third step, The fault location can be determined using the phasor of the current Ids and the stationary coordinate q-axis current Iqs.

In the fault diagnosis method of the inverter, when the stop coordinate d axis current Ids is in the range of 120 to 240 degrees and the stop coordinate q axis current Iqs is in the range of 240 to 360 degrees based on the a phase voltage Va, (Ids) is in the range of 120 to 240 degrees and the stop coordinate q-axis current (Iqs) is in the range of 0 to 120 degrees based on the a-phase voltage (Va) Axis current (Ids) is in the range of 0 to 120 degrees and the stationary coordinate q-axis current (Iqs) is in the range of 0 to 120 degrees based on the a-phase voltage (Va) , It can be judged that the c-phase switch module has failed.

As described above, according to the present invention, it is possible to quickly and accurately find a fault location from voltage and current information of a three-phase inverter without using an expensive gate driver, thereby improving the reliability of a power control system, It can save time and money.

1 is a diagram illustrating a power regulation system (PCS) in which an inverter fault diagnosis apparatus according to an embodiment of the present invention is used.
2 is a diagram illustrating a detailed configuration of the inverter.
3 is a diagram illustrating a procedure for detecting a fault switch module.
4 is a diagram illustrating waveforms of a reference current and a fault current on the time axis.
5 is a diagram illustrating a phasor of the stop coordinate d axis current Ids and the stop coordinate q axis current Iqs according to the open failure of the switch module in the discharge mode.
6 is a diagram illustrating a pager of a stationary coordinate d-axis current Ids and a stationary coordinate q-axis current Iqs according to an open failure of the switch module in the charge mode.
FIG. 7 is a diagram illustrating a phasor of three-phase modulation indexes MIa, MIb, and MIc according to an open failure of a switch module in a standby mode.
8 is a diagram illustrating a phasor of a stop coordinate d axis current Ids and a stop coordinate q axis current Iqs in response to a short circuit failure of the switch module.

Hereinafter, some embodiments of the present invention will be described in detail with reference to exemplary drawings. It should be noted that, in adding reference numerals to the constituent elements of the drawings, the same constituent elements are denoted by the same reference numerals whenever possible, even if they are shown in different drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

In describing the components of the present invention, terms such as first, second, A, B, (a), and (b) may be used. These terms are intended to distinguish the constituent elements from other constituent elements, and the terms do not limit the nature, order or order of the constituent elements. When a component is described as being "connected", "coupled", or "connected" to another component, the component may be directly connected to or connected to the other component, It should be understood that an element may be "connected," "coupled," or "connected."

FIG. 1 is a diagram illustrating a power control system 100 in which an inverter fault diagnosis apparatus according to an embodiment of the present invention is used. FIG. 2 is a diagram illustrating a detailed configuration of an inverter 120. Referring to FIG. Hereinafter, description will be made with reference to Figs. 1 and 2. Fig.

The power conditioning system 100 may be connected to an energy storage device and a power system to receive electrical energy from the power system 180 to charge the energy storage device or to supply energy stored in the energy storage device to the power system 180. To this end, the power conditioning system 100 may include an inverter 120, a fault diagnosis device 140, an LC filter 160, and a transformer 180.

The power control system 100 charges the remaining rated voltage through the breaker to charge the DC link capacitor 122 through the resistor during initial startup using a controller (not shown) ) Prevents overcurrents that can occur due to abrupt charging in a zero-charge state. Also, the power control system 100 detects the voltage and current of the inverter 120 and performs phase synchronization with the power system through a phase lock loop (PLL), and outputs the d-axis (effective axis) and q Axis) axis and voltage and current are used to control the reactive / reactive power.

The inverter 120 converts DC voltage into AC and outputs the AC voltage. For this purpose, the inverter 120 may include a DC link capacitor 122 and a three-phase switch module 124. The DC link capacitor 122 receives the DC voltage from the energy storage device, stores the DC voltage, and allows the DC voltage to be used in the inverter 120. The three-phase switch module 124 is a switch module used for converting a direct current voltage into a three-phase alternating current. Referring to Fig. 2, the three-phase switch module 124 may include an a-phase switch module 124a, a b-phase switch module 124b and a c-phase switch module 124c. Each of the switch modules 124a, 124b and 124c of each phase is connected to the switching elements Sa1, Sb1 and Sc1 connected to the positive terminal of the DC link capacitor 122 and the switching element Sa2 connected to the negative terminal of the DC link capacitor 122 , Sb2, Sc2). The switching elements Sa1, Sb1, Sc1, Sa2, Sb2 and Sc2 used for the switch modules 124a, 124b and 124c of the respective phases can be used for general power semiconductor switching elements such as a MOSFET, an IGBT, a thyristor, have. The inverter 120 may be operated with only one stack or two or more inverter stacks may be operated in parallel.

The failure of the inverter 120 is mainly caused by the failure of the switch module. In the present invention, a method is described in which of the switch modules (124a, 124b, 124c) of each phase of the inverter (120) the failure occurs and whether the failure type is an open failure or a short failure. Failures of the switch modules 124a, 124b and 124c are typical of open failure and short-circuit failure. The open fault means the open state between collector and emitter (C-E) in case of IGBT, and the open state between D-S (Drain-Source) in case of MOSFET. Short circuit failure means short circuit between collector (C-E) in the case of IGBT and short circuit between D-S (Drain-Source) in case of MOSFET.

Referring again to FIG. 1, the fault diagnosis apparatus 140 diagnoses a fault of a three-phase inverter used in connection with a power system and determines a correct fault location. For this, the fault diagnosis apparatus 140 may include a detection unit 142 and a fault location determination unit 144.

The detection unit 142 detects the phase voltages Va, Vb, and Vc of the inverter 120 and the phase currents Ia, Ib, and Ic. The phase voltages Va, Vb, and Vc and phase currents Ia, Ib, and Ic are used to determine the failure status and failure location through dq conversion. The detection unit 142 detects the line voltages Vab, Vbc and Vca instead of detecting the phase voltages Va, Vb and Vc of the inverter 120 and detects the phase voltages Va, Vb and Vc through appropriate calculation You may.

The fault position determination unit 144 receives the phase voltages Va, Vb, and Vc and the phase currents Ia, Ib, and Ic from the detection unit 142 and obtains the stationary coordinate d axis current Ids and the stationary coordinate q Axis current (Iqs), rotational coordinate d axis current (Ide), rotational coordinate q axis current (Iqe), modulation index (MIa, MIb, MIc) of each phase, and the like are used to determine the fault location and fault location . A method for determining whether a failure has occurred and a failure location by the failure location determination unit 144 will be described in detail below.

The LC filter 160 functions to remove noise from the AC voltage output from the inverter 120, and a conventional filter can be used.

Transformer 180 is connected between inverter 120 and the power system to perform isolation and / or voltage conversion functions. It is desirable to construct a Y-Delta transformer to minimize the influence of the third harmonic. The winding ratio of the transformer can be determined according to the power system situation and the dc side voltage.

3 is a diagram illustrating a procedure for detecting a fault switch module. The method for determining whether the inverter is faulty or faulty will be described in detail below with reference to FIG. 3, but the voltage and current used to determine the fault and the fault location And the modulation index, and their relational expressions.

In the present invention, phase currents Va, Vb, and Vc of the inverter and phase currents Ia, Ib, and Ic of the inverter are detected to determine the failure and the failure position, Axis current Iqs, the rotation coordinate d axis current Ide, the rotation coordinate q axis current Iqe, the stop coordinate d axis current reference value Ids *, the stop coordinate q axis current reference value Iqs * The modulation index (MIa, MIb, MIc) is calculated and utilized. Ids, Iqs, Ids *, Iqs *, MIa, MIb, MIc, and the like, respectively.

The phase voltages Va, Vb, and Vc of the inverter and the phase currents Ia, Ib, and Ic can be detected by the detection unit.

The stationary coordinate d axis current Ids and the stationary coordinate q axis current Iqs can be obtained from the following equations (1) and (2) by multiplying Ia, Ib, and Ic by a stationary transformation matrix P:

(1)

(2)

Next, the rotational coordinate d-axis current Ide and the rotational coordinate q-axis current Iqe can be obtained by multiplying Ids and Iqs by a rotational transformation matrix R as shown in the following Equation 3 and Equation 4, respectively.

(3)

The modulation indexes MIa, MIb, and MIc of each phase are obtained by using the reference values Va *, Vb *, Vc * and the DC link voltage (Vdc) of the three-phase voltage used for controlling the inverter in the inverter controller as shown in Equation . When the inverter controller controls based on the dq axis, the reference values Va *, Vb * and Vc * of the three-phase voltage can be obtained from the d-axis voltage reference value and the q-axis voltage reference value through inverse transformation,

(4)

The stop coordinate d axis current reference value (Ids *) and the stop coordinate q axis current reference value (Iqs *) are reference currents in the dq axis generated by the controller so that the inverter outputs the active power reference value and the reactive power reference value.

The thus obtained stationary coordinate d axis current Ids, stationary coordinate q axis current Iqs, rotational coordinate d axis current Ide, rotational coordinate q axis current Iqe, stationary coordinate d axis current reference value Ids * A method of determining the fault status and fault location using the stationary coordinate q-axis current reference value Iqs * and the modulation indexes MIa, MIb and MIc of each phase will be described with reference to FIG.

First, the inverter is started (S302), and it is determined whether or not the absolute value of Ide is larger than the first threshold value (S304). If the absolute value of Ide is larger than the first threshold value, the inverter determines that it is in the operating mode in which the power is being processed. In step S306, if the absolute value of Ide is smaller than the first threshold value, The process proceeds to step S316. That is, the first threshold value may be appropriately set according to the operating condition of the inverter as a reference value for determining whether or not the inverter is performing actual power processing.

Whether the absolute value (Ia + Ib + Ic |) of the sum of the phasors of the three-phase currents is smaller than the second threshold value is determined if the absolute value of Ide is larger than the first threshold value (S306). If the absolute value (Ia + Ib + Ic |) of the sum of the phasors of the three-phase current is smaller than the second threshold value, it is determined that the phase currents of the three phases are in a normal state of equilibrium, and the process returns to step S304. If the absolute value (Ia + Ib + Ic |) of the sum of the phasors of the three-phase current is larger than the second threshold value, it is determined that the three-phase current is in a failure state in which the phase current is not balanced and the process proceeds to step S308. Here, the second threshold value can be appropriately selected in consideration of the measurement error as a reference value for determining whether the three-phase current is in equilibrium and the normal variability of the three-phase current in the normal operation state.

If it is determined in step S306 that a failure has occurred, it is determined whether at least one of the phase currents Ia, Ib, and Ic is greater than a fourth threshold value (S308). If at least one of the phase currents Ia, Ib, and Ic is larger than the fourth threshold value, it is determined that the switch module constituting the inverter is short-circuited (step S310). Using the pagers of Ids and Iqs, (S314). If all of the phase currents Ia, Ib, and Ic are smaller than the fourth threshold value, it is determined that the switch module is open (step S312). Then, the correct failure location is determined using the phasor of Ids and Iqs (S314). The reason for distinguishing between the open fault and the short fault of the switch module is that the phasor pattern of Ids and Iqs varies depending on the type of the fault. Therefore, the fault type is classified and a pager pattern for determining the fault location according to the corresponding fault type is selected It is for use. Here, the fourth threshold value is a reference value that can distinguish the short-circuit failure of the switch module, and can be appropriately set according to the operating conditions of the inverter.

If it is determined in step S304 that the absolute value of Ide is smaller than the first threshold value and it is determined to be the standby mode, the process proceeds to step S316 to calculate the absolute value of the sum of the phasor values MIa, MIb, MIc |) Is smaller than the third threshold value. If the absolute value (| MIa + MIb + MIc |) of the sum of phasor values of MIa, MIb and MIc is smaller than the third threshold value, the three phases in the standby mode are in a normal operating state of equilibrium. If it is determined in step S318 that an open failure has occurred in the standby mode, if the absolute value (MIa + MIb + MIc |) of the sum of the phasor values MIa, MIb and MIc is greater than the third threshold value Use the phaser to determine the correct fault location. Here, the third threshold may be appropriately selected in consideration of a reference value for determining whether the three phases are balanced in the standby mode. In the case of an open failure in the standby mode, the actual phase current hardly flows, so it is difficult to determine the failure and the failure position using the phasor of Ids and Iqs. In the present invention, whether or not an idle mode is used is first discriminated by using Ide, and if it is determined that the idle mode is used, it is possible to accurately determine whether an open failure has occurred and a failure position even in the idle mode by using the modulation index of each phase.

Next, with reference to FIG. 4 to FIG. 9, a detailed determination criterion for determining a failure position using Ids and Iqs or MIa, MIb, and MIc will be described.

Figure 4 illustrates current waveforms over time, Ids * illustrating the expected current at normal operating conditions, and Ids illustrating the actual current at fault conditions. In normal operation, Ids should have the same magnitude and phase as Ids *. However, when a failure occurs, Ids differs in magnitude and phase from Ids *. In the present invention, a method of determining the fault location by analyzing the size and phase (i.e., phasor) of Ids, Iqs, MIa, MIb, and MIc in a fault situation is used.

According to the present invention, the open-fault and short-circuit faults of the switch modules of each phase are simulated under various operating conditions, and the phasor of the voltage, current, and modulation indexes at the time of failure is analyzed. As a result, We have found that there are distinctive features in the pager and use the method to find the fault location. That is, in the case of the open failure in the discharge mode, the open failure in the charge mode, and the short failure (common to the discharge mode, the charge mode, and the standby mode), the failure location can be identified by using the pager of Ids and Iqs, Open faults can be identified by using the pagers of MIa, MIb, and MIc. 5 to 8 show typical phasors according to the failure of each switch module at the time of an open failure in a discharge mode, an open failure in a charge mode, an open failure in a standby mode, and a short failure (no mode classification) .

FIG. 5 shows a pager for the open failure in the discharge mode when Ide is positive in the case of the open failure in the operation mode in step S308 of FIG. Here, if Ide has a positive value, it means that the inverter supplies energy from the energy storage device to the power system, so it is referred to as a 'discharge mode' in terms of the energy storage device.

5 shows Ids, Iqs, Ids * and Iqs * according to the open failure of the switch module (124a, 124b, 124c in Fig. 2) on each phase during discharging. 5, when the stationary coordinate d-axis current Ids is above the reference value Ids * and the magnitude of the stationary coordinate d-axis current Ids is smaller than the magnitude of the stationary coordinate q-axis current Iqs, If the stop coordinate d-axis current Ids is above the reference value Ids * and the stop coordinate d-axis current Ids is larger than the stop coordinate q-axis current Iqs, If the stop coordinate d axis current Ids is higher than the reference value Ids * and the stop coordinate q axis current Iqs is above the reference value Iqs * It can be judged.

FIG. 6 shows a pager for the open failure in the charge mode, in which Ide is negative in the case of the open failure in the operation mode in step S308 of FIG. Here, when Ide has a negative value, energy is input from the power system and energy is stored in the energy storage device through the inverter. Therefore, the energy storage device is referred to as a 'charging mode'.

6 shows Ids, Iqs, Ids *, Iqs * according to the open failure of the switch module (124a, 124b, 124c in Fig. 2) on each phase during charging. 6, when the magnitude of the stationary coordinate d-axis current Ids is smaller than the value obtained by subtracting the fifth threshold value from the reference value Ids *, it is determined that the a-phase switch module has failed, Axis switch module Ids is higher than the reference value Ids * and the stationary coordinate q-axis current Iqs is higher than the reference value Iqs *, the stop-coordinate d-axis current Ids is determined as the reference value Ids *) And the stop coordinate q-axis current (Iqs) is above the reference value (Iqs *), it can be judged that the c-phase switch module is faulty. Here, the fifth threshold value can be appropriately selected in consideration of the fact that a slight difference from Ids *, which is the reference value, may occur due to a deviation according to operating conditions even in a non-failure situation.

FIG. 7 shows phasors of the three-phase modulation indexes MIa, MIb, and MIc and the phase voltages Va, Vb, and Vc in the case where the open failure in the standby mode is determined in step S316 of FIG. 6, when the a-phase MI (MIa) is higher than the a-phase voltage Va, the b-phase MI (MIb) is higher than the b-phase voltage Vb, Phase MI (MIa) is higher than the a-phase voltage (Va) and the b-phase MI (MIb) is higher than the b-phase voltage (Vb) phase MI (MIa) is above the a-phase voltage (Va) and the b-phase MI (MIb) is greater than the a-phase voltage ) Is higher than the b-phase voltage (Vb) and the c-phase MI (MIc) is higher than the c-phase voltage (Vc).

8 is a diagram illustrating a pager of the stop coordinate d-axis current Ids and the stop coordinate q-axis current Iqs in the case where it is determined that the short-circuit failure of the switch module is detected in step S308 of FIG. 8, when the stationary coordinate d-axis current Ids is in the range of 120 to 240 degrees and the stationary coordinate q-axis current Iqs is in the range of 240 to 360 degrees based on the a-phase voltage Va, If the stopping coordinate d-axis current (Ids) is within the range of 120 to 240 degrees and the stop coordinate q-axis current (Iqs) is within the range of 0 to 120 degrees based on the a-phase voltage (Va) If the stop coordinate d axis current (Ids) is in the range of 0 to 120 degrees and the stop coordinate q axis current (Iqs) is in the range of 0 to 120 degrees based on the a-phase voltage (Va) It can be determined that the phase switch module has failed.

As described above, according to the present invention, the phase voltage and the phase current of the inverter, and the phase coordinate of the stationary coordinate d-axis current Ids, the stationary coordinate q-axis current Iqs, and the modulation index MIa, MIb, It is possible to judge not only the open failure in the discharge mode, the open failure in the charge mode, the open failure in the stand-by mode, and the short-circuit failure in the entire mode, This makes it possible to quickly and accurately identify the fault location from the voltage and current information of the three-phase inverter without using expensive gate drivers, thereby improving the reliability of the power control system and reducing maintenance time and cost. Can be saved.

It is to be understood that the terms "comprises", "comprising", or "having" as used in the foregoing description mean that the constituent element can be implanted unless specifically stated to the contrary, But should be construed as further including other elements. All terms, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, unless otherwise defined. Commonly used terms, such as predefined terms, should be interpreted to be consistent with the contextual meanings of the related art, and are not to be construed as ideal or overly formal, unless expressly defined to the contrary.

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents should be construed as falling within the scope of the present invention.

100: Power Control System (PCS)
120: Inverter
122: DC link capacitor
124: Three-phase switch module
140: Inverter fault diagnosis device
142:
144: Failure position determination unit
160: LC filter
180: Transformer

Claims (14)

delete delete delete delete delete delete delete A fault diagnosis method of an inverter performed by a fault diagnosis apparatus of a three-phase inverter connected to a power system,
A first step of detecting phase voltages (Va, Vb, Vc) and phase currents (Ia, Ib, Ic) of an inverter;
(Ia, Ib, Ic) of the three-phase currents (Ia, Ib, Ic) when the absolute value of the rotational coordinate d axis current Ide is compared with the first threshold value and the absolute value of the rotational coordinate d axis current Ide is greater than the first threshold value Phase current i Ide is greater than a first threshold value, it is determined that the idle mode is selected and the modulation index MIa, MIb, and MIc) to a third threshold value;
The absolute value of the sum of phasor of the three-phase currents Ia, Ib and Ic is compared with the second threshold value as a result of comparing the absolute value of the sum of phasor of the three-phase currents Ia, Ib, Phase currents Ia, Ib, and Ic are determined to be in a normal state, and returns to the first step. If the absolute value of the sum of phasor of the three-phase currents Ia, Ib, and Ic is not less than the second threshold value, , Ib, Ic) to a fourth threshold value;
As a result of comparing the absolute value of the sum of the phasors of the modulation indexes (MIa, MIb, MIc) of the three phases with the third threshold value, the absolute value of the sum of phasors of the modulation indexes (MIa, MIb, MIc) And if the absolute value of the sum of phasor values of the modulation indexes (MIa, MIb, MIc) of the three phases is not smaller than the third threshold value, it is determined as an open failure in the standby mode A fourth step of judging;
If it is determined that at least one of the three-phase currents Ia, Ib, and Ic is greater than a fourth threshold value as a result of comparing the three-phase currents Ia, Ib, and Ic with the fourth threshold value, If the three-phase currents (Ia, Ib, Ic) are not larger than the fourth threshold value, it is determined as an open failure in the operation mode;
A sixth step of determining a failure position by using a pager of three-phase modulation indexes (MIa, MIb, MIc) according to a determination criterion for a standby mode open failure when it is determined that the open failure is in the standby mode in the fourth step;
A seventh step of determining a fault position using the pseudo-static coordinate d-axis current Ids and the static coordinate q-axis current Iqs in accordance with a judgment criterion for a short circuit fault in the fifth step; And
If it is determined in step 5 that the open failure is present in the operation mode, it is determined that the discharge mode is satisfied if the rotational coordinate d axis current Ide has a positive value, and the stop coordinate d axis current Axis fault current Ids and the stationary coordinate q-axis current Iqs. If the rotational coordinate d-axis current Ide has a negative value, it is determined to be a charging mode, And determining the fault location using the pseudo-coordinate d axis current Ids and the stationary coordinate q axis current Iqs according to the following equation. 9. The method of claim 8, wherein determining the failure location using the phasor of the three-phase modulation index (MIa, MIb, MIc) according to a determination criterion for the idle mode open failure comprises:
When the a phase MI (MIa) is higher than the a phase voltage Va and the b phase MI (MIb) is above the b phase voltage Vb and the c phase MI (MIc) is higher than the c phase voltage Vc , It is determined that the a-phase switch module has failed,
When the a phase MI (MIa) is higher than the a phase voltage Va and the b phase MI (MIb) is higher than the b phase voltage Vb and the c phase MI (MIc) is higher than the c phase voltage Vc It is determined that the b-phase switch module has failed,
when the a phase MI (MIa) is higher than the a phase voltage Va and the b phase MI (MIb) is higher than the b phase voltage Vb and the c phase MI (MIc) is higher than the c phase voltage Vc And the c-phase switch module is judged to be faulty. delete 9. The method of claim 8, wherein determining a failure location using a pause of the stationary coordinate d-axis current (Ids) and the stationary coordinate q-axis current (Iqs) according to a determination criterion for the discharge mode open-
If the stop coordinate d-axis current Ids is above the reference value Ids * and the magnitude of the stop coordinate d-axis current Ids is smaller than the stop coordinate q-axis current Iqs, it is determined that the a- Axis current (Ids) is larger than the reference value (Ids *) and the size of the stop coordinate d-axis current (Ids) is larger than the size of the stop coordinate q-axis current (Iqs) , And determines that the c-phase switch module is faulty when the stop coordinate d-axis current Ids is higher in phase than the reference value Ids * and the stationary coordinate q-axis current Iqs is above the reference value Iqs * Fault diagnosis method of inverter. 9. The method of claim 8, wherein determining a fault location using a pause of the stationary coordinate d-axis current (Ids) and the stationary coordinate q-axis current (Iqs) according to a determination criterion for the charge mode open-
Axis switch module Ids is smaller than a value obtained by subtracting the fifth threshold value from the reference value Ids * and the stop coordinate d axis current Ids is smaller than the reference value Ids * Axis current Iqs is higher than the reference value Iqs *, it is determined that the b-phase switch module is faulty. If the stop coordinate d-axis current Ids is higher than the reference value Ids * And the c-phase switch module is judged to be faulty when the coordinate q-axis current (Iqs) is above the reference value (Iqs *). delete 9. The method of claim 8, wherein determining a fault location using a pager of stationary coordinate d-axis currents Ids and stationary coordinate q-axis currents Iqs according to a determination criterion for the short-
If the stop coordinate d axis current (Ids) is within the range of 120 to 240 degrees and the stop coordinate q axis current (Iqs) is within the range of 240 to 360 degrees based on the a-phase voltage (Va) ,
If the stop coordinate d axis current Ids is in the range of 120 to 240 degrees and the stop coordinate q axis current Iqs is in the range of 0 to 120 degrees based on the a-phase voltage Va, it is determined that the b- ,
If the stop coordinate d axis current (Ids) is in the range of 0 to 120 degrees and the stop coordinate q axis current (Iqs) is in the range of 0 to 120 degrees based on the a-phase voltage (Va) Wherein the fault diagnosis method comprises the steps of:

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