Fault tolerant power converter topology for switched reluctance motors

Abstract

The fault-tolerant power converter topology comprises a bidirectional switching power converter, an A-phase winding, a B-phase winding, a C-phase winding and a D-phase winding which form a loop, the bidirectional switching power converter comprises a direct-current power source and a switching tube, and the switching tube comprises a power transistor and a bidirectional switching tube. At least two switching tubes are arranged between every two adjacent windings, and the bidirectional switching tubes are located between bridge arms of the A-phase winding and the D-phase winding. When an open-circuit fault occurs in a switch tube of a bridge arm where each phase winding of the converter is located, other switch tubes and bidirectional switch tubes of a common bridge arm between the phase and the two phases can be controlled through fault-tolerant operation, so that a current path of a fault phase in each working mode is reconstructed, and fault-tolerant operation under a fault condition is realized. Moreover, the power converter topology uses few types of power devices, is simple in structure, reduces the system cost, is suitable for each phase of motor and control strategy, and has a good application prospect.

Description

Technical Field

[0001] The present invention belongs to the technical field of switched reluctance motors, and particularly relates to a fault-tolerant power converter topology for switched reluctance motors. Background Art

[0002] Traditional asymmetric half-bridge power converters are widely used in switched reluctance motors due to their simple structure and independent phases. When a fault occurs in one phase arm, the other phase arms are not affected. When an open-circuit fault occurs in the power converter, the phase arm cannot be excited, and the switched reluctance motor operates in a single-phase loss mode. The lost output torque can only be compensated by other phases; when a short-circuit fault occurs in the power converter, the output torque ripple of the switched reluctance motor increases, seriously affecting the output performance of the motor. With the increasing requirements for reliability in working scenarios, the disadvantages of traditional asymmetric half-bridge power converters limit the fault-tolerant operation ability of switched reluctance motors and cannot meet variable working conditions and emerging faults.

[0003] Aiming at the problem that the fault-tolerant ability of traditional asymmetric half-bridge power converters cannot meet safety requirements in high-reliability scenarios and affects the normal operation of switched reluctance motor systems, the present invention proposes a fault-tolerant power converter topology for switched reluctance motors based on bidirectional switches. Summary of the Invention

[0004] To solve the above problems, the present invention proposes a fault-tolerant power converter topology for switched reluctance motors.

[0005] The fault-tolerant power converter topology for switched reluctance motors of the present invention includes: a bidirectional switch power converter forming a loop, an A-phase winding, a B-phase winding, a C-phase winding, and a D-phase winding. The bidirectional switch power converter includes a DC power supply and switching tubes. The switching tubes include power transistors and bidirectional switch tubes.

[0006] At least two switching tubes are provided between adjacent two-phase windings. There is one bidirectional switch tube, which is located between the bridge arms of the A-phase winding and the D-phase winding. The bidirectional switch tube is in an idle state under normal conditions. Fault-tolerant operation is achieved by switching the bidirectional switch tube during a fault and sharing the bridge arms and transistors between two phases, and reconstructing the current path under an open-circuit fault of the switching tube.

[0007] When the switched reluctance motor adopts a soft chopping control strategy, each phase winding of the power converter has three working states: an exciting state, a zero-voltage freewheeling state, and a demagnetizing state.

[0008] The power transistor includes switching transistors S1, S2, S3, S4, S5, S6, S7, S8, S9, S10, S11, S12, and S13, and there is one bidirectional switching transistor, which is the bidirectional switching transistor Sad.

[0009] The switching transistors S1 and S2 are located on the left bridge arm of the A-phase winding. The switching transistors S3, S4, and S5 are located on the common bridge arm of the A-phase winding and the B-phase winding. The switching transistors S6, S7, and S8 are located on the common bridge arm of the B-phase winding and the C-phase winding. The switching transistors S9, S10, and S11 are located on the common bridge arm of the C-phase winding and the D-phase winding. The switching transistors S12 and S13 are located on the right bridge arm of the D-phase winding. The bidirectional switching transistor Sad is located between the bridge arms of the A-phase winding and the D-phase winding, with one end connected to the input terminal of the A-phase winding and the other end connected to the output terminal of the D-phase winding.

[0010] When open-circuit faults occur in the switching transistors S1 and S2, only the A-phase winding is affected. When open-circuit faults occur in the switching transistors S3, S4, and S5, the operating modes of the A-phase winding and the B-phase winding are affected. When open-circuit faults occur in the switching transistors S6, S7, and S8, the operating modes of the B-phase winding and the C-phase winding are affected. When open-circuit faults occur in the switching transistors S9, S10, and S11, the operating modes of the C-phase winding and the D-phase winding are affected. When open-circuit faults occur in the switching transistors S12 and S13, only the D-phase winding is affected.

[0011] When open-circuit faults occur in the switching transistors, different current path reconstructions will occur during the fault-tolerant operation of the converter:

[0012] When an open-circuit fault occurs in the switching transistor S1, the current path reconstruction under the excitation mode of the A-phase winding is performed;

[0013] When an open-circuit fault occurs in the switching transistor S2, the current path reconstruction under the zero-voltage freewheeling mode and the demagnetization mode of the A-phase winding is performed;

[0014] When an open-circuit fault occurs in the switching transistor S3, the current path reconstruction under the demagnetization mode of the A-phase winding and the excitation mode of the B-phase winding is performed;

[0015] When an open-circuit fault occurs in the switching transistor S5, the current path reconstruction under the excitation mode of the A-phase winding, the zero-voltage freewheeling mode of the A-phase winding or the B-phase winding, and the demagnetization mode of the B-phase winding is performed;

[0016] When an open-circuit fault occurs in the switching transistor S6, the current path reconstruction under the demagnetization mode of the B-phase winding and the excitation mode of the C-phase winding is performed;

[0017] When the switching transistor S8 has an open - circuit fault, the current path reconstruction is performed under the B - phase winding excitation mode, zero - voltage free - wheeling mode, C - phase winding zero - voltage free - wheeling mode, and demagnetization mode.

[0018] When the switching transistor S9 has an open - circuit fault, the current path reconstruction is performed under the C - phase winding demagnetization mode and D - phase winding excitation mode.

[0019] When the switching transistor S11 has an open - circuit fault, the current path reconstruction is performed under the C - phase winding excitation mode, C - phase winding or D - phase winding zero - voltage free - wheeling mode, and D - phase winding demagnetization mode.

[0020] When the switching transistor S12 has an open - circuit fault, the path reconstruction is performed under the D - phase winding demagnetization mode.

[0021] When the switching transistor S13 has an open - circuit fault, the current path reconstruction is performed under the D - phase winding excitation mode and zero - voltage free - wheeling mode.

[0022] The motor is a four - phase 8 / 6 switched reluctance motor.

[0023] The beneficial effect of the present invention is that the proposed two - way switch fault - tolerant power converter topology, with fewer types of power devices, when an open - circuit fault occurs in the switching transistors of the bridge arms where each phase winding of the converter is located, can control the other switching transistors and bidirectional switching transistors of the common bridge arms between the faulty phase and the two - phase by its fault - tolerant operation, so that the current paths in each working mode of the faulty phase are reconstructed, thereby realizing fault - tolerant operation in case of faults, improving the reliability of the switched reluctance motor system, and the power converter topology uses fewer types of power devices, has a simple structure, reduces the system cost, is applicable to various - phase motors and control strategies, and has good application prospects. Description of the Drawings

[0024] Figure 1 is the fault - tolerant power converter topology for a switched reluctance motor of the present invention.

[0025] Figure 2 is the working state diagram of the A - phase of the switched reluctance motor.

[0026] Figure 3 is the fault - tolerant operation state diagram under the open - circuit fault of S1.

[0027] Figure 4 is the fault - tolerant operation state diagram under the open - circuit fault of S2.

[0028] Figure 5 is the fault - tolerant operation state diagram under the open - circuit fault of S3.

[0029] Figure 6 is the fault - tolerant operation state diagram under the open - circuit fault of S5.

[0030] Figure 7 It is the fault-tolerant operation state diagram under the open-circuit fault of S6.

[0031] Figure 8 It is the fault-tolerant operation state diagram under the open-circuit fault of S8.

[0032] Figure 9 It is the fault-tolerant operation state diagram under the open-circuit fault of S9.

[0033] Figure 10 It is the fault-tolerant operation state diagram under the open-circuit fault of S11.

[0034] Figure 11 It is the fault-tolerant operation state diagram under the open-circuit fault of S12.

[0035] Figure 12 It is the fault-tolerant operation state diagram under the open-circuit fault of S13. Detailed implementation manners

[0036] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present invention, and should not be construed as a limitation to the present invention.

[0037] As Figures 1 - 12 shown, the fault-tolerant power converter topology for a switched reluctance motor of the present invention includes: a bidirectional switch power converter forming a loop, an A-phase winding, a B-phase winding, a C-phase winding, and a D-phase winding. The motor is a four-phase 8 / 6 switched reluctance motor. The bidirectional switch power converter includes a DC power supply U and switching tubes. The switching tubes are divided into power transistors and bidirectional switch tubes, as Figure 1 shown. The switching tubes include switching tube S1, switching tube S2, switching tube S3, switching tube S4, switching tube S5, switching tube S6, switching tube S7, switching tube S8, switching tube S9, switching tube S10, switching tube S11, switching tube S12, switching tube S13, and switching tube Sad. Among them, switching tubes S1 to S13 are power transistors, and switching tube Sad is a bidirectional switch tube.

[0038] The switching transistors S1 and S2 are respectively the upper and lower transistors of the left bridge arm of the A-phase winding. The switching transistors S3, S4, and S5 are located on the common bridge arm of the A-phase winding and the B-phase winding. For the A-phase winding, S3 and S4 are the upper transistors, and S5 is the lower transistor; for the B-phase winding, S3 is the upper transistor, and S4 and S5 are the lower transistors. The switching transistors S6, S7, and S8 are located on the common bridge arm of the B-phase winding and the C-phase winding. For the B-phase winding, S6 and S7 are the upper transistors, and S8 is the lower transistor; for the C-phase winding, S6 is the upper transistor, and S7 and S8 are the lower transistors. The switching transistors S9, S10, and S11 are located on the common bridge arm of the C-phase winding and the D-phase winding. For the C-phase winding, S9 and S10 are the upper transistors, and S11 is the lower transistor; for the D-phase winding, S9 is the upper transistor, and S10 and S11 are the lower transistors. The switching transistors S12 and S13 are respectively the upper and lower transistors of the right bridge arm of the D-phase winding. Sad is located between the bridge arms of the A-phase winding and the D-phase winding, with one end connected to the input terminal of the A-phase winding and the other end connected to the output terminal of the D-phase winding.

[0039] For the open-circuit fault of the power triode, the bidirectional switching transistor is in the idle state under normal conditions. Fault-tolerant operation can be achieved by switching the bidirectional switching transistor during the fault and sharing the bridge arm and transistors between two phases, thereby reconstructing the current path under the open-circuit fault of the switching transistor. When the switched reluctance motor adopts the soft chopping control strategy, each phase winding of the power converter will have three working states: the exciting state, the zero-voltage freewheeling state, and the demagnetizing state. Taking the A-phase winding as an example, as Figure 2 shown, when in the exciting state, the current starts from the positive pole of the power supply and flows into the negative pole of the power supply through the switching transistor S1, the A-phase winding, and the switching transistor S5 respectively; when in the zero-voltage freewheeling state, the current flows through the switching transistor S2, the A-phase winding, and the switching transistor S5 in the original direction; when in the demagnetizing state, the current starts from the negative pole of the power supply and flows into the positive pole of the power supply through the switching transistor S2, the A-phase winding, the switching transistors S4 and S3.

[0040] When an open-circuit fault occurs in the switching transistors on each phase bridge arm, it will affect the current transmission in each working mode. And due to the existence of the common bridge arm, when a fault occurs in the switching transistor on it, the current path reconstruction may involve adjacent two-phase windings. The specific impacts of open-circuit faults of each switching transistor on the operation of each phase winding are shown in Table 1, Table 2, Table 3, and Table 4:

[0041] Table 1

[0042]

[0043] Table 2

[0044]

[0045] Table 3

[0046]

[0047] Table 4

[0048]

[0049] According to Tables 1 to 4, the current path reconstruction of the power converter under fault-tolerant operation when each switching tube fails can be analyzed. It can be seen from Table 1 that switching tubes S1 and S2 only affect the A-phase winding. When switching tube S1 has an open-circuit fault, as Figure 3 shown, the bidirectional switching tube Sad performs the current path reconstruction in the excitation mode of the A-phase winding. The current starts from the positive pole of the power supply U, passes through switching tube S12, bidirectional switching tube Sad, the A-phase winding, and switching tube S5 in sequence, and then flows into the negative pole of the power supply U. When switching tube S2 has an open-circuit fault, as Figure 4 shown, the current passes through the A-phase winding, switching tube S5, switching tube S13, and bidirectional switching tube Sad to perform the path reconstruction in the zero-voltage freewheeling mode; the current passes through the A-phase winding, switching tube S4, switching tube S3, the power supply U, switching tube S13, and bidirectional switching tube Sad to perform the current path reconstruction in the demagnetization mode.

[0050] It can be seen from Tables 1 and 2 that switching tubes S3, S4, and S5 are located in the common bridge arm of the A-phase winding and the B-phase winding. When these three switching tubes fail, the operating modes of both phases will be affected. When switching tube S3 has an open-circuit fault, as Figure 5 shown, at this time, the current passes through the A-phase winding, switching tube S4, the B-phase winding, switching tube S7, switching tube S6, the power supply U, and switching tube S2 to perform the path reconstruction in the demagnetization mode of the A-phase winding; the current passes through the positive pole of the power supply U, switching tube S12, bidirectional switching tube Sad, the A-phase winding, switching tube S4, the B-phase winding, and switching tube S8 to return to the negative pole of the power supply U to perform the current path reconstruction in the excitation mode of the B-phase winding. When switching tube S5 has an open-circuit fault, as Figure 6 shown, the current passes through the positive pole of the power supply U, switching tube S1, the A-phase winding, switching tube S4, the B-phase winding, and switching tube S8 to return to the negative pole of the power supply U to perform the path reconstruction in the excitation mode of the A-phase winding; the current passes through the A-phase winding, switching tube S4, the B-phase winding, switching tube S8, and switching tube S2 to perform the current path reconstruction in the zero-voltage freewheeling mode of the A-phase winding or the B-phase winding; the current passes through the B-phase winding, switching tube S7, switching tube S6, the power supply U, switching tube S2, the A-phase winding, and switching tube S4 to perform the current path reconstruction in the demagnetization mode of the B-phase winding.

[0051] As can be seen from Table 2 and Table 3, the switching transistors S6, S7, and S8 are located in the common bridge arm of the B-phase winding and the C-phase winding, which can affect the operating modes of the two phases. When an open-circuit fault occurs in the switching transistor S6, as Figure 7 shown, the current passes through the B-phase winding, the switching transistor S7, the C-phase winding, the switching transistor S10, the switching transistor S9, the power supply U, the switching transistor S5, and the switching transistor S4 to perform path reconstruction in the demagnetization mode of the B-phase winding; the current passes through the positive pole of the power supply U, the switching transistor S3, the B-phase winding, the switching transistor S7, the C-phase winding, and the switching transistor S11 and returns to the negative pole of the power supply U to perform current path reconstruction in the excitation mode of the C-phase winding. When an open-circuit fault occurs in the switching transistor S8, as Figure 8 shown, the current passes through the positive pole of the power supply U, the switching transistor S3, the B-phase winding, the switching transistor S7, the C-phase winding, and the switching transistor S11 and returns to the negative pole of the power supply U to perform path reconstruction in the excitation mode of the B-phase winding; the current passes through the B-phase winding, the switching transistor S7, the C-phase winding, the switching transistor S11, the switching transistor S5, and the switching transistor S4 to perform current path reconstruction in the zero-voltage freewheeling mode of the B-phase winding; the current passes through the C-phase winding, the switching transistor S11, the switching transistor S2, the switching transistor S1, and the switching transistor S6 to perform current path reconstruction in the zero-voltage freewheeling mode of the C-phase winding; the current passes through the C-phase winding, the switching transistor S10, the switching transistor S9, the power supply U, the switching transistor S5, the switching transistor S4, the B-phase winding, and the switching transistor S7 to perform current path reconstruction in the demagnetization mode of the C-phase winding.

[0052] As can be seen from Table 3 and Table 4, the switching transistors S9, S10, and S11 are located in the common bridge arm of the C-phase winding and the D-phase winding, which can affect the operating modes of the two phases. When an open-circuit fault occurs in the switching transistor S9, as Figure 9 shown, the current passes through the C-phase winding, the switching transistor S10, the D-phase winding, the switching transistor S12, the power supply U, the switching transistor S8, the switching transistor S7, the C-phase winding, and the switching transistor S10 to perform path reconstruction in the demagnetization mode of the C-phase winding; the current passes through the positive pole of the power supply U, the switching transistor S6, the C-phase winding, the switching transistor S10, the D-phase winding, and the switching transistor S13 and returns to the negative pole of the power supply U to perform current path reconstruction in the excitation mode of the D-phase winding. When an open-circuit fault occurs in the switching transistor S11, as Figure 10 shown, the current passes through the positive pole of the power supply U, the switching transistor S6, the C-phase winding, the switching transistor S10, the D-phase winding, and the switching transistor S13 and returns to the negative pole of the power supply U to perform path reconstruction in the excitation mode of the C-phase winding; the current passes through the C-phase winding, the switching transistor S10, the D-phase winding, the switching transistor S13, the switching transistor S8, and the switching transistor S7 to perform current path reconstruction in the zero-voltage freewheeling mode of the C-phase winding or the D-phase winding; the current passes through the D-phase winding, the switching transistor S12, the power supply U, the switching transistor S8, the switching transistor S7, the C-phase winding, and the switching transistor S10 to perform current path reconstruction in the demagnetization mode of the D-phase winding.

[0053] As can be seen from Table 4, the switching transistors S12 and S13 only affect the D-phase winding. When an open-circuit fault occurs in the switching transistor S12, as Figure 11 shown, the current passes through the D-phase winding, the bidirectional switching transistor Sad, the switching transistor S1, the power supply U, the switching transistor S11, and the switching transistor S10 to perform path reconstruction in the demagnetization mode of the D-phase winding. When an open-circuit fault occurs in the switching transistor S13, as Figure 12 shown, the current passes through the positive pole of the power supply U, the switching transistor S9, the D-phase winding, the bidirectional switching transistor Sad, and the switching transistor S2 to return to the negative pole of the power supply U to perform path reconstruction in the magnetization mode of the D-phase winding; the current passes through the D-phase winding, the bidirectional switching transistor Sad, the switching transistor S2, the switching transistor S11, and the switching transistor S10 to perform current path reconstruction in the zero-voltage freewheeling mode of the D-phase winding.

[0054] Although the above embodiments have been shown and described, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Any changes, modifications, substitutions, and variations made by those of ordinary skill in the art to the above embodiments are within the protection scope of the present invention.

Claims

1. A fault-tolerant power converter topology for a switched reluctance motor, characterized in that: include: A bidirectional switching power converter, an A-phase winding, a B-phase winding, a C-phase winding and a D-phase winding forming a loop, wherein the bidirectional switching power converter comprises a DC power supply and a switch tube, wherein the switch tube comprises a power transistor and a bidirectional switch tube, At least two switch tubes are arranged between two adjacent windings, and there is one bidirectional switch tube, which is located between the bridge arms of the A-phase winding and the D-phase winding. The bidirectional switch tube is in an idle state under normal circumstances. The fault-tolerant operation is achieved by switching the bidirectional switch tube during a fault and sharing the bridge arm and transistor between the two phases, and the current path under the open circuit fault of the switch tube is reconstructed; When the switched reluctance motor adopts a soft chopping control strategy, each phase winding of the power converter will have three working states: excitation state, zero voltage freewheeling state and demagnetization state.

2. The fault-tolerant power converter topology for a switched reluctance motor according to claim 1, characterized in that: The power transistors include switch tubes S1, S2, S3, S4, S5, S6, S7, S8, S9, S10, S11, S12 and S13, and there is one bidirectional switch tube, which is a bidirectional switch tube Sad.

3. The fault-tolerant power converter topology for a switched reluctance motor according to claim 2, characterized in that: The switch tubes S1 and S2 are located on the left bridge arm of the A-phase winding, the switch tubes S3, S4 and S5 are located on the common bridge arm of the A-phase winding and the B-phase winding, the switch tubes S6, S7 and S8 are located on the common bridge arm of the B-phase winding and the C-phase winding, the switch tubes S9, S10 and S11 are located on the common bridge arm of the C-phase winding and the D-phase winding, the switch tubes S12 and S13 are located on the right bridge arm of the D-phase winding, and the bidirectional switch tube Sad is located between the bridge arms of the A-phase winding and the D-phase winding, with one end connected to the input end of the A-phase winding and the other end connected to the output end of the D-phase winding.

4. The fault-tolerant power converter topology for a switched reluctance motor according to claim 3, characterized in that: When an open-circuit fault occurs in the switch tubes S1 and S2, only the A-phase winding is affected; when an open-circuit fault occurs in the switch tubes S3, S4, and S5, the working modes of the A-phase winding and the B-phase winding are affected; when an open-circuit fault occurs in the switch tubes S6, S7, and S8, the working modes of the B-phase winding and the C-phase winding are affected; when an open-circuit fault occurs in the switch tubes S9, S10, and S11, the working modes of the C-phase winding and the D-phase winding are affected; when an open-circuit fault occurs in the switch tubes S12 and S13, only the D-phase winding is affected.

5. The fault-tolerant power converter topology for a switched reluctance motor according to claim 4, characterized in that: When the switch fails, different current paths will be reconstructed in the converter fault-tolerant operation: When an open circuit fault occurs in the switch tube S1, the current path reconstruction in the A-phase winding excitation mode is performed; When an open-circuit fault occurs in the switch tube S2, the current path reconstruction in the zero voltage freewheeling mode and the demagnetization mode of the A-phase winding is performed; When an open circuit fault occurs in the switch tube S3, the current path reconstruction in the A-phase winding demagnetization mode and the B-phase winding excitation mode is performed; When an open circuit fault occurs in the switch tube S5, current path reconstruction is performed in the A-phase winding excitation mode, the A-phase winding or the B-phase winding zero voltage freewheeling mode, and the B-phase winding demagnetization mode; When an open circuit fault occurs in the switch tube S6, the current path reconstruction in the B-phase winding demagnetization mode and the C-phase winding excitation mode is performed; When an open circuit fault occurs in the switch tube S8, current path reconstruction is performed in the B-phase winding excitation mode and zero voltage freewheeling mode, and the C-phase winding zero voltage freewheeling mode and demagnetization mode; When an open circuit fault occurs in the switch tube S9, the current path reconstruction in the C-phase winding demagnetization mode and the D-phase winding excitation mode is performed; When an open circuit fault occurs in the switch tube S11, current path reconstruction is performed in the C-phase winding excitation mode, the C-phase winding or D-phase winding zero voltage freewheeling mode, and the D-phase winding demagnetization mode; When an open circuit fault occurs in the switch tube S12, path reconstruction in the demagnetization mode of the D-phase winding is performed; When an open-circuit fault occurs in the switch tube S13, the current path reconstruction in the D-phase winding excitation mode and the zero voltage freewheeling mode is performed.

6. The fault-tolerant power converter topology for a switched reluctance motor according to claim 1, characterized in that: The motor is a four-phase 8 / 6 switched reluctance motor.

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