KR20120113910A - Fault-tolerant control apparatus under the open-circuit fault condition of 3-phase ac/dc pwm converter and method thereof - Google Patents

Abstract

PURPOSE: An open circuit fault tolerant control device of a three phase AC and DC PWM converter and a method thereof are provided to increase a power factor of a system by reducing an unbalance between each phase and a harmonic wave included in a current during an open circuit failure. CONSTITUTION: A three phase current value is converted into a two phase rest frame current value(S110). A current vectorposition angle is obtained by an arctangent calculation of the coverted two phase rest frame current value(S120)(S130). An open circuit fault phase is detected based on the obtained current vector position angle(S140). When the open circuit fault phase is detected, a switching signal for fault tolerant control is provided to a converter. [Reference numerals] (AA) Start; (BB) End; (S110) Converting a three phase current value into a two phase rest frame current value; (S120) Operating the converted two phase rest frame current value with arctangent calculation; (S130) Obtaining a current vector position angle by generating an angle according to the mark of the current; (S140) Detecting a fault phase based on the current vector position angle

Description

Fault-tolerant control apparatus under the open-circuit fault condition of 3-phase AC / DC PWM converter and method

The present invention relates to a three-phase AC / DC PWM converter, and more particularly, to an open circuit fault tolerance control technique of a three-phase AC / DC PWM converter.

Three-phase AC / PC PWM converters have been used for a long time in many industries. As the interest in power quality increases, sanctions are severed, and the range of use continues to increase due to linkage with existing power systems following the introduction of renewable energy sources. On the other hand, about 38% of the causes of the failure of the PWM converter are estimated to be caused by a failure of a switching device such as an IGBT. The failure of the switching element can be divided into short circuit failure and open circuit failure. In the case of a short circuit failure, the power is usually cut off by a protection circuit such as a breaker or a fuse, but if not, the switching element is not only destroyed, but also a fatal damage to the peripheral element.

On the other hand, if an open circuit failure occurs, it does not immediately lead to system shutdown but continues to operate with degraded performance. The current contains a lot of harmonic components, and each phase causes an unbalance, as well as a pulsation of the system frequency component in the DC voltage generated. If this abnormal operation continues, malfunctions of other devices due to accumulated fatigue due to unstable operation may lead to secondary failures in the converter system or the load or system. Therefore, it is necessary to stop the converter system and repair the broken part. However, fault-tolerant control is essential for special applications such as semiconductor and steel processes where the system must continue to operate after failure.

It is an object of the present invention to provide a technical scheme that enables fault-tolerant control of open circuit failure in a three-phase AC / DC PWM converter.

High-performance three-phase AC / DC PWM converters are usually driven by space vector control techniques. At this time, if an open circuit failure of the switching element occurs, current cannot flow through the failed switching element, and current flows only through the reverse reflux diode located in the faulty phase, thereby acting as a diode rectifier for a specific period. . Three phase balanced currents with a 120 degree phase difference at normal time are changed to unbalanced current waveforms including harmonics after failure.

In this case, the controller cannot produce the desired voltage command from the converter because of the open circuit failure. In other words, the voltage command vector desired by the controller goes out as a voltage vector of distorted magnitude and direction due to the converter failure. And this distorted output voltage vector produces distorted current.

To solve this problem, it is necessary to correct the portion where the voltage command from the output of the final controller is converted to PWM. Assuming that the exact phase in which the open circuit failure occurred is known, the switch pattern must be changed in such a way as to accurately generate the voltage command vector or to produce the closest vector regardless of the failed switch.

An open circuit failure of a three-phase AC / DC PWM converter operating by receiving a switching signal subjected to a space vector pulse width modulated according to a command voltage according to an aspect of the present invention for achieving the above technical problem. The permitting device applies a fault diagnosis unit for diagnosing an open circuit fault of the converter, and a switching signal for fault tolerance control to the converter instead of the space vector pulse width modulated switching signal when the fault is diagnosed by the fault diagnosis unit. It includes a fault tolerance control unit.

Here, the fault diagnosis unit detects an open circuit fault phase of the converter, and the fault tolerance control unit checks the detected fault phase and the space vector pulse width modulated switching signal, and according to a result of the confirmation, the fixed fixation control. Generate a switching signal for and apply it to the converter.

The fault diagnosis unit detects an open circuit fault phase of the converter on the basis of the two-phase stationary coordinate current value converted from the three-phase current value. Specifically, the fault diagnosis unit takes an arc tangent of the current values of the stationary coordinate system of the two phases, generates an angle according to the sign of the current, obtains a current vector position angle, and monitors the change amount thereof to detect a fault phase.

On the other hand, the open circuit fault tolerance control method of the three-phase AC / DC PWM converter according to an aspect of the present invention for achieving the above technical problem is a step of detecting the open circuit failure phase of the three-phase AC / DC PWM converter, and If the fault phase is detected, applying a switching signal for fault tolerance control to the converter instead of the space vector pulse width modulated switching signal.

The detecting may include converting a three-phase current value into a two-phase stationary coordinate current value, taking an arc tangent of the converted two-phase stationary current value, and generating an angle according to a sign of the current after taking the arc tangent. Acquiring a current vector position angle, and detecting an open circuit fault phase based on the obtained current vector position angle.

The present invention can greatly improve performance and reliability by only changing a simple PWM switching pattern when an open circuit failure occurs in a high performance three-phase AC / DC PWM converter using general space vector control. In the case of an open circuit failure, the harmonics included in the current and the imbalance between phases are greatly reduced, and the voltage pulsation of the DC stage is also reduced. Thus, the efficiency increases as the power factor of the system increases. In addition, reliability can be greatly improved by reducing the cause of secondary failures that may occur due to open circuit fault operation.

In particular, in certain application areas where emergency stop is not possible while the system is in operation, it has the advantage that continuous operation can be performed with high performance and reliability even in the event of an open circuit failure. Minimal waste of time before replacing a failed converter system.

1 is a waveform diagram of phase currents and currents before and after failure of a three-phase AC / DC PWM converter open circuit;
2 is a waveform diagram of currents generated when a failure of each of the six switching elements of a PWM converter occurs.
3 is a three phase AC / DC PWM converter with open circuit failure of the A phase top switch.
4 is a waveform diagram of phase currents and currents in a normal operation of a three-phase AC / DC PWM converter.
Fig. 5 is a waveform diagram of phase currents and currents at the time of an open circuit failure of an A phase upper switch of a three-phase AC / DC PWM converter.
Fig. 6 is a waveform diagram of phase current and current angular variation in the open circuit failure of the A phase upper switch of a three-phase AC / DC PWM converter.
7 is a plan view of a voltage vector of a space vector PWM (SVPWM).
8 is a normal switching pattern in SecIII.
9 is a switching pattern when a phase A top switch failure in SecIII.
Figure 10 is a pattern during the permissible control in the A phase upper switch failure state in SecIII.
11 is a block diagram of an open circuit failure tolerance control device of a three-phase AC / DC PWM converter according to an embodiment of the present invention.
Fig. 12 is a waveform diagram of a detection signal based on the static coordinate system dq-axis current, current angle, and fault diagnosis technique.
Fig. 13 is a graph of phase current waveforms and DC stage voltage waveforms and their FFT results in steady state;
Fig. 14 is a graph of the phase current waveforms and DC stage voltage waveforms and the FFT results of the voltages at the time of open circuit failure of the upper switch of the phase A;
Fig. 15 is a graph of phase current waveforms and DC stage voltage waveforms after fault-tolerant control and FFT result graphs of the voltages.
16 is a flowchart illustrating an open circuit fault tolerance control method of a three-phase AC / DC PWM converter according to an embodiment of the present invention.
FIG. 17 is a detailed flowchart of S100 shown in FIG. 16;

BRIEF DESCRIPTION OF THE DRAWINGS The foregoing and further aspects of the present invention will become more apparent from the following detailed description of preferred embodiments with reference to the accompanying drawings. Hereinafter, the present invention will be described in detail to enable those skilled in the art to easily understand and reproduce the present invention.

1 is a waveform diagram of phase currents and currents before and after failure of a three-phase AC / DC PWM converter open circuit.

High-performance three-phase AC / DC PWM converters typically use space vector control. When the three-phase current (A-phase current, B-phase current, C-phase current) measured in the normal operation is expressed by the dq-axis stationary coordinate system value, it can be expressed by Equation 1 as follows.

The current vector of Equation 1 rotates at a constant system frequency speed regardless of steady state or transient state. At this time, the amount of change in the current angle (curent angle) for each sampling can be represented by the following equation (2).

Where ω is the system frequency and T _s is the sampling period. Equation 2 above always has a constant value when there is no open failure of the switch. However, if an open circuit failure occurs, the phase current cannot flow through the switching elements of the open circuit, only through the freewheeling diode. Therefore, the phase current operates in two-phase conduction instead of three-phase conduction in the specific section shown in FIG. As a result, in the particular section shown in FIG. 1, the current in the fault phase remains almost zero, and only two phase currents may flow. At this moment, the angle of the current vector is a constant value as shown in the particular section in FIG.

2 is a waveform diagram of currents generated at the failure of each of the six switching elements of the PWM converter.

Figure 2 shows the current angles appearing in the open circuit failure of each of the phase A top switch, phase A bottom switch, phase B top switch and phase B bottom switch, phase C top switch and phase C bottom switch. As can be seen from Figure 2, the current angle generated when the open circuit failure of each switch is different. This means that current elements can detect switching elements that have an open circuit failure.

FIG. 3 is a circuit diagram of a three-phase AC / DC PWM converter having an open circuit failure of an upper phase switch of A phase. FIG. 4 is a waveform diagram of phase current and current angles during normal operation of a three-phase AC / DC PWM converter. Phase current and current waveforms when the open circuit of the A-phase upper switch of the three-phase AC / DC PWM converter fails. FIG. 6 shows the phase current of the open circuit of the A-phase upper switch of the three-phase AC / DC PWM converter. This is a waveform diagram of the angular current variation amount.

In the normal operation of the circuit shown in FIG. 3, as shown in FIG. 4, a current three phase current waveform and a current angle having a constant change obtained from the current can be obtained. However, if an open circuit failure of the switching element occurs during the operation of a three-phase AC / DC PWM converter, the phase current cannot flow through the switching element of the open circuit and only current flows through the reverse reflux diode located in the fault phase. It acts like a diode rectifier. Thus, the three-phase balanced currents with 120-degree phase difference in normal state are changed to unbalanced current waveforms including harmonics after failure.

When looking at the phenomenon appearing in the current, if the current flowing through the diode is changed in the direction of the current that must pass through the failed switching element, the current on the phase will remain at zero current until the next diode conduction. This means that currents in three-phase conduction have a two-phase conduction section from the section in which the current direction of the faulty phase changes to the section in which the next diode conducts. In the two-phase conduction section, one of the three phases does not operate like the current waveform of the BLDC motor, and current flows through the remaining two phases. Thus, one phase is positive current, the other is negative current and the other is zero current.

3 illustrates a case where the A phase upper switch is broken. If the A phase upper switch fails, as shown in FIG. 4, the current i _aN through the switching element cannot flow, and only the current i _aP through the freewheeling diode can flow. Accordingly, the current waveform and the distorted current angle shown in FIG. 5 appear. At this time, the amount of change in the current angle is shown as shown in Figure 6, it can be seen that the amount of change in the current angle stays near zero for a certain time. This is because the period is changed from the three-phase conduction section to the two-phase conduction section and the current vector stays in the same direction for a certain time. In FIG. 6, an open circuit fault detection interval may be determined as a failure of the upper switch of the phase A through FIG. 2.

7 is a plan view of a voltage vector of a space vector PWM (SVPWM), FIG. 8 is a switching pattern in normal operation when the voltage command V ^* is located at secIII, and FIG. 9 is a voltage pattern V ^* at secIII. when the switch is located in the pattern of an open circuit failure of the a-phase upper switching state, Figure 10 is a pattern when the voltage command V ^* is permitted controlled by the phase a upper switch failure condition in secⅢ.

As illustrated in FIG. 7, when the voltage command V ^* is located at secIII, the effective vector times of V ₃ and V ₄ in the normal SVPWM switching pattern as shown in FIG. 8 are T ₁ and T _2, respectively. This and as shown in Figure 9, under fault conditions zero vector V is ₇ because it operates as a place of V ₄ can not be generated, the effective vector application times of V ₄ is increased by T _0/2. 10 shows the switching pattern appearing in secIII when the fault tolerance control according to the present invention is applied. For the time of the effective voltage vector V ₄ to compensate for such failure before, the zero vector V ₇ is a vector V ₀ removed and spirit As the addition time interval of the zero vector V _{0 0} T / 2 becomes T _0. This ensures that the application time of the effective vectors V ₃ and V ₄ is completely compensated as before the failure.

Table 1 below shows a sector-by-sector failure state vector in case of an open circuit failure of an upper phase switch of A phase. And Table 2 shows the compensated vector by the fault-to-sector fault tolerance control in the open circuit failure of the upper phase switch of the A phase. In Table 1 and Table 2, secII and secV are divided according to the sign of A phase current.

Normal condition Open-circuit fault condition of A-phase top switch Sector Vector Abnormal Vector Faulty Condition Vector time Sector SecⅠ V ₀ , V ₁ , V ₂ , V ₇ - Normal SecⅠ SecⅡ
V ₀ , V ₂ , V ₃ , V ₇
- Normal SecII V ₂ , V ₇ V ₀ (T _0/2 ), V ₃ (T ₁ + T ₂ ), V ₄ (T _0/2 ) SecⅢ SecⅢ V ₀ , V ₃ , V ₄ , V ₇ V ₇ V ₀ (T _0/2 ), V ₃ (T), V ₄ (T ₂ + T _0/2 ) SecⅢ Sec IV V ₀ , V ₄ , V ₅ , V ₇ V ₇ V ₀ (T _0/2 ), V ₅ (T ₁ ), V ₄ (T ₂ + T _0/2 ) Sec IV SecⅤ
V ₀ , V ₅ , V ₆ , V ₇
V ₆ , V ₇ V ₀ (T _0/2 ), V ₅ (T ₁ + T ₂ ), V ₄ (T _0/2 ) Sec IV - Normal SecV SecVI V ₀ , V ₆ , V ₁ , V ₇ - Normal SecVI

Open-circuit fault condition of A-phase top switch Fault-tolerance control Sector Vector time Vector time Compensation SecⅠ Normal NA NA SecⅡ
Normal NA NA V ₀ (T _0/2 ), V ₃ (T ₁ + T ₂ ), V ₄ (T _0/2 ) _{V 0 (T 0), V} 3 (T 1/2 + T 2) Partially SecⅢ V ₀ (T _0/2 ), V ₃ (T), V ₄ (T ₂ + T _0/2 ) V ₀ (T ₀ ), V ₃ (T ₁ ), V ₄ (T ₂ ) Perfectly Sec IV V ₀ (T _0/2 ), V ₅ (T ₁ ), V ₄ (T ₂ + T _0/2 ) V ₀ (T ₀ ), V ₅ (T ₁ ), V ₄ (T ₂ ) Perfectly SecⅤ
V ₀ (T _0/2 ), V ₅ (T ₁ + T ₂ ), V ₄ (T _0/2 ) _{V 0 (T 0), V} 5 (T 1 + T 2/2) Partially Normal NA NA SecVI Normal NA NA

In SecII, SecIV, and SecV, a compensation technique according to the fault tolerance control described above may be applied. However, Sec I and Sec VI are excluded from compensation. This is because, as shown in FIG. 3, the A phase upper switch failure does not affect the positive current i _aP due to the freewheeling diode D ₁ . On the other hand, the above table shows the compensated vector by the fault-tolerant control for each sector in the case of the A phase upper switch failure. Similarly, experiments can identify sector-specific failure state vectors in the case of other switch failures and obtain compensated vectors for fault tolerance control.

11 is a block diagram of an open circuit fault tolerance control device of a three-phase AC / DC PWM converter.

The first current converter 100 converts i _as , i _bs , i _cs , measured by CT (Current Transformer), to i ^s _d , i ^s _q , which are dq-axis stop coordinate system current values. The second current converter 200 converts the stationary coordinate current converted by the first current converter 100 into the synchronous coordinate currents i ^e _ds and i ^e _qs . The voltage controller 300 receives a DC terminal voltage and a DC terminal voltage command to generate a d-axis command current i ^{e *} _ds and a q-axis command current i ^{e *} _qs to generate a current controller (Current Controller) ( 400). The current controller 400 receives the d-axis current i ^e _ds and the q-axis current i ^e _qs from the second current converter 200, and the d-axis command current i ^{e *} _ds and q-axis command from the voltage controller 300. The current i ^{e *} _qs is input and the d-axis command voltage v ^{e *} _ds and the q-axis command voltage v ^{e *} _qs are generated and output to the third current converter 500. The third current converter 500 receives the d-axis command voltage v ^{e *} _ds and the q-axis command voltage v ^{e *} _qs from the current controller 400 to generate a three-phase command voltage v ^* _abc . The pulse width modulator 600 receives a three-phase command voltage v ^* _abc from the third current converter 500 and performs space vector pulse width modulation (SVWWM) to configure a converter. Outputs a switching signal for controlling the on / off of the devices.

Hereinafter, the fault diagnosis unit 700 and the fault tolerance control unit 800 will be described. The fault diagnosis unit 700 and the fault tolerance control unit 800 may be implemented as part of a controller for controlling the three-phase AC / DC PWM converter. The failure diagnosis unit 700 diagnoses whether an open circuit of the PWM converter has failed. The fault diagnosis unit 700 according to an aspect of the present invention determines whether an open circuit of the switching elements has failed based on a current value of dq-axis stop coordinate system i ^s _d , i ^s _q converted by the first current converter 100. To judge. Specifically, in the normal operation of the PWM converter, the current in the two-phase stationary coordinate system draws a circle rotating at a constant speed. The speed of the rotating current vector here will always be the same value as the grid power supply frequency. If an open circuit failure occurs, currents in three-phase conduction are operated in two-phase conduction with one phase current staying at zero for a certain period. In this case, the current vector of the two-phase stationary coordinate system remains constant. In other words, it means that the speed of the current vector, which always rotates at a constant grid power frequency, has decreased. Therefore, the failure diagnosis unit 700 may detect an open circuit failure of the PWM converter and its phase by monitoring the amount of change in the current vector of the two-phase stationary coordinate system.

The failure diagnosis unit 700 takes an arc tangent (tan ⁻¹ ) of the current value of the two-phase stationary coordinate system and generates an angle according to the sign of the current. This results in a current vector position angle of 0 to 360 degrees moving at the speed of the system frequency. The failure diagnosis unit 700 acquires the current vector position angle at every sampling period of the controller and continuously monitors each variation in comparison with the previous sampling value (previous current vector position angle). At this time, when the amount of change decreases and points to a constant current vector for 1.38 [ms] for 30 degrees of rotation in normal operation, it can be determined as an open circuit failure. As shown in Fig. 2, since the angle when a failure is found is different for every six switches of the three-phase AC / DC PWM converter, the failure diagnosis unit 700 can immediately diagnose which switching element has failed. There is a number. 12 shows a waveform in which the fault confirmation signal is displayed from the fault coordinate system dq-axis current, the current angle, and the fault detection signal information after the fault has occurred.

On the other hand, the fault tolerance control unit 800 is a configuration for performing fault tolerance control, the fault phase (Fault phase) detected by the fault diagnosis unit 700 and the space vector pulse width modulation of the pulse width modulator 600 Perform fault tolerance control based on this. In detail, the fault tolerance control unit 800 has fault information provided by the fault diagnosis unit 700 and the switching signal output from the pulse width modulator 600 to look up a look-up table as shown in Table 2 to control fault tolerance. Check the compensation vector for, and generates a switching signal according to the identified compensation vector and apply it to the PWM converter.

When the switching signal by the fault tolerance control unit 800 is applied to the PWM converter, the switching signal output from the pulse width modulator 600 should not be applied to the PWM converter. To this end, the fault tolerance control apparatus according to an aspect of the present invention further includes an optional output unit. If the fault detection signal is not applied, the selective output unit 900 outputs the switching signal of the pulse width modulator 600 to the PWM converter. In contrast, when the fault detection signal is applied, the selective output unit 900 outputs the switching signal of the fault tolerance control unit 800 to the PWM converter instead of the switching signal of the pulse width modulator 600. In one embodiment, the selective output unit 900 may be implemented as a switching switch that can receive another switching signal according to whether the failure detection signal is input, and transfer it to the PWM converter.

Fig. 13 is a graph of the phase current waveform and the DC stage voltage waveform in the steady state and the FFT result graph of the voltage, and Fig. 14 is a graph of the phase current waveform and the DC stage voltage waveform and the FFT result graph at the open circuit failure of the A phase upper switch. Fig. 15 is a graph of the phase current waveform, the DC stage voltage waveform after the fault tolerance control, and the FFT result graph of the voltage.

As shown in FIG. 13, in the steady state of the PWM converter, a balanced three-phase current having a phase difference of 120 degrees flows, and there is no pulsation in the DC stage voltage. However, as shown in FIG. 14, when an open circuit failure occurs, unbalanced currents having harmonics appear. It can be seen that the DC stage voltage also vibrates with pulsation of the system frequency component. However, when the fault tolerance control is performed, it can be seen that harmonics are reduced in phase current, unbalance is eliminated, and the DC stage voltage pulsation is also greatly reduced as shown in FIG. 15. In Sec III and Sec IV, it can be seen that the compensation is completely completed. In Sec II and Sec V, partial guarantees are made, resulting in fast response.

16 is a flowchart illustrating an open circuit fault tolerance control method of a three-phase AC / DC PWM converter according to an exemplary embodiment of the present invention.

First, the fault tolerance control device detects an open circuit fault phase of the PWM converter (S100). When the fault phase is detected, the fault tolerance control apparatus generates a designated switching signal for fault tolerance control according to the detected fault phase and the switching signal output from the pulse width modulator 600 (S200). In detail, in S200, the fault tolerance control apparatus checks a compensation vector corresponding to a switching signal output from the fault phase and the pulse width modulator 600 with reference to a look-up table as shown in Table 2, and switches according to the identified compensation vector. Generate a signal. When the switching signal based on the compensation vector is generated, the fault tolerance control apparatus outputs the switching signal according to the compensation vector to the PWM converter instead of the switching signal output from the pulse width modulator 600 (S300).

17 is a detailed flowchart of S100 shown in FIG. 16.

The fault-tolerant control device converts the three-phase current value measured by the CT (Current Transformer) into the two-phase stationary coordinate current value (S110). Then, the fault-tolerant control device obtains the current vector position angle by taking an arc tangent (tan ⁻¹ ) of the converted two-phase stationary coordinate current value and generating an angle according to the sign of the current (S120) (S130). The fault-tolerant control device detects which phase of the open circuit fault and the phase in which the fault occurs based on the obtained current vector position angle (S140). Specifically, the fault-tolerant control device acquires the current vector position angle at every sampling period, and continuously monitors the amount of change in the current vector position angle in comparison with the previous sampling value to detect whether an open circuit fault occurs and the phase in which the fault has occurred. .

So far I looked at the center of the preferred embodiment for the present invention. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. Therefore, the disclosed embodiments should be considered in an illustrative rather than a restrictive sense. The scope of the present invention is defined by the appended claims rather than by the foregoing description, and all differences within the scope of equivalents thereof should be construed as being included in the present invention.

100: first current converter 200: second current converter
300: voltage controller 400: current controller
500: third current converter 600: pulse width modulator
700: fault diagnosis unit 800: fault tolerance control unit
900: optional output

Claims (10)

In the open circuit fault tolerance device of a three-phase AC / DC PWM converter that operates by receiving a space vector pulse width modulated switching signal according to the command voltage,
A fault diagnosis unit for diagnosing an open circuit fault of the converter; And
A fault tolerance controller for applying a switching signal for fault tolerance control to the converter when the fault is diagnosed by the fault diagnosis unit, instead of the space vector pulse width modulated switching signal;
Open circuit fault tolerance control device of a three-phase AC / DC PWM converter, comprising a. The method of claim 1,
The fault diagnosis unit detects an open circuit fault phase of the converter,
The fault tolerance control unit checks the detected fault phase and the space vector pulse width modulated switching signal, generates a switching signal for a predetermined fixed admission control according to a result of the check, and applies the converted signal to the converter. Open circuit fault tolerance control device for three-phase AC / DC PWM converters. The method of claim 2,
If the fault phase is not detected by the fault diagnosis unit, the space vector pulse width modulated switching signal is output to the converter. When the fault phase is detected by the fault diagnosis unit, a switching signal for the fixed permission control is output. An optional output unit outputting to the converter;
Open circuit fault tolerance control device of a three-phase AC / DC PWM converter, characterized in that it further comprises. The method according to claim 2 or 3,
And the fault diagnosis unit detects an open circuit fault phase of the converter based on a current value of the two-phase stationary coordinate system converted from the current value of the three phases. The method of claim 4, wherein
The fault diagnosis unit detects a fault phase by taking an arc tangent of the two-phase stationary coordinate current value and generating an angle according to the sign of the current to obtain a current vector position angle and monitoring the change amount thereof. Open circuit fault tolerance control device for DC PWM converters. The method of claim 5,
And the fault diagnosis unit obtains the current vector position angle at each sampling period and monitors the amount of change in the current vector position angle by comparing with a previous sampling value. Detecting an open circuit fault phase of the three-phase AC / DC PWM converter; And
If the fault phase is detected, applying a switching signal for fault tolerance control to the converter instead of the space vector pulse width modulated switching signal;
Open circuit fault tolerance control method of a three-phase AC / DC PWM converter comprising a. 8. The method of claim 7, wherein said detecting comprises:
Converting a current value of the three phases into a static coordinate system current value of the two phases;
Taking an arc tangent of the converted two-phase stationary coordinate current value;
Acquiring the current vector position angle by generating an angle according to the sign of the current after taking the arc tangent; And
Detecting an open circuit fault phase based on the obtained current vector position angle;
Open circuit fault tolerance control method of a three-phase AC / DC PWM converter comprising a. 9. The method of claim 8,
Acquiring the current vector position angle is performed every sampling period,
The detecting of the fault phase may include detecting a fault phase by comparing a current sampling value with a previous sampling value. 10. The method of any one of claims 7 to 9, wherein applying a switching signal for the fault tolerance control to the converter:
Confirming the detected fault phase and the space vector pulse width modulated switching signal;
Generating a switching signal according to a compensation vector for fault tolerance control corresponding to the verification result;
Outputting the generated switching signal to the converter;
Open circuit fault tolerance control method of a three-phase AC / DC PWM converter comprising a.

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