阅读说明：本技术 一种开关磁阻电机断路故障容错控制方法 (Fault-tolerant control method for open circuit fault of switched reluctance motor ) 是由 胡薇 朱天翔 龚昌明 宋天涯 陈波波 程康恒 朱鹏飞 邢玉成 李明锋 于 2021-03-15 设计创作，主要内容包括：本发明公开了一种开关磁阻电机断路故障容错控制方法,该开关磁阻电机断路故障容错控制方法通过三相四桥臂开关磁阻电机容错控制系统实现,所述三相四桥臂开关磁阻电机容错控制系统包括一个三相开关磁阻电机、一个直流电源、一个四桥臂逆变器,绕组采用星形连接方式,且其中性点连接第四个桥臂,用于解决开关磁阻电机驱动电路工作时功率变换器件发生断路故障的问题,不仅能够针对单个开关管断路进行容错控制,而且对于不在同桥臂的任意两管断路都可以进行容错控制,保证电机系统性能较正常运行时基本不变,本发明电路接线简单、成本低、绕组利用率高,有效实现了功率变换器件发生断路故障后的容错运行,提高了系统的可靠性。(The invention discloses a fault-tolerant control method for open circuit faults of a switched reluctance motor, which is realized by a fault-tolerant control system of a three-phase four-leg switched reluctance motor, the fault-tolerant control system of the three-phase four-leg switched reluctance motor comprises the three-phase switched reluctance motor, a direct-current power supply and a four-leg inverter, windings adopt a star connection mode, and neutral points of the windings are connected with a fourth leg, so that the fault-tolerant control method is used for solving the problem that the power conversion device has open circuit faults when a switched reluctance motor driving circuit works, not only can carry out fault-tolerant control on the open circuit of a single switching tube, but also can carry out fault-tolerant control on the open circuits of any two tubes which are not in the same leg, ensures that the performance of the motor system is basically unchanged when the motor system is normally operated, has the advantages of simple circuit connection, low cost and high winding utilization rate, and effectively, the reliability of the system is improved.)

1. The fault-tolerant control method for the open circuit fault of the switched reluctance motor is characterized by being realized by a three-phase four-leg switched reluctance motor fault-tolerant control system, wherein the three-phase four-leg switched reluctance motor fault-tolerant control system comprises a three-phase switched reluctance motor, a direct-current power supply and a four-leg inverter, a winding adopts a star connection mode, and a neutral point of the winding is connected with a fourth leg;

and the excitation current is divided into six power-on modes A when the control system of the two-phase excited switched reluctance motor works normally⁺C^-、A⁺B^-、B^-C⁺、C⁺A^-、A^-B⁺、B⁺C^-And when the power conversion device has an open circuit fault, the power-on mode is changed to complete fault-tolerant control.

2. The open-circuit fault-tolerant control method of the switched reluctance motor according to claim 1, wherein the control method comprises the following steps:

the method comprises the following steps: when the switching tube of any bridge arm of the driving circuit is broken, particularly when the switching tube of the third bridge arm is broken S6, adjusting the switching angle of a fault tube signal and transmitting the signal to the fourth bridge arm lower tube to conduct A, B two-phase current;

step two: regulating the signal switching angle of the fault tube again and transmitting the signal to another healthy switching tube S5 of the fault bridge arm to generate a current which has the opposite direction to the original C-phase current and has the same value as the original C-phase current so as to ensure that the output torque before and after the fault is unchanged;

step three: energization pattern change of field current to A⁺C⁺、A⁺B^-、B^-C⁺、C⁺A^-、A^-B⁺、B⁺C⁺And completing fault-tolerant control.

3. The open-circuit fault-tolerant control method of the switched reluctance motor according to claim 1, wherein the control method comprises the following steps:

the method comprises the following steps: when the switching tubes of two different bridge arms of the driving circuit are in an open circuit condition, specifically, when the switching tubes of S3 and S6 are in an open circuit condition, adjusting a signal switching angle of a fault tube S3 and transmitting the signal switching angle to a fourth bridge arm upper tube S7, and adjusting a signal switching angle of a fault tube S6 and transmitting the signal switching angle to a fourth bridge arm lower tube S8;

step two: then adjusting the signal switching angle of the fault tube S3 and transmitting the signal switching angle to the healthy switching tube S4 of the same bridge arm, and similarly transmitting the signal switching angle of S6 to the healthy switching tube S5 of the same bridge arm;

step three: energization pattern change of field current to A⁺C⁺、A⁺B^-、B^-C⁺、C⁺A^-、A^-B^-、B^-C⁺And completing fault-tolerant control.

Technical Field

The invention belongs to the technical field of power converters of switched reluctance motors, and particularly relates to a fault-tolerant control method for open circuit faults of a switched reluctance motor.

Background

The switched reluctance motor has firm and simple structure and low cost, and the bipolar controlled three-phase switched reluctance motor system has simple wiring, wide speed regulation range and smaller torque pulsation and is suitable for occasions with high speed and severe environment. However, due to aging of components, overcurrent and overvoltage and other reasons, in the operation process of the motor, faults are inevitable, the power converter and the driving circuit thereof are used as a central actuating mechanism for system control and are the weak link which is most prone to faults in the system, the faults of the power converter destroy the balance state of the operation of the driving system, torque gaps and even braking torque which cannot be inhibited are generated, and the whole system is damaged due to long-term fault operation, so that fault-tolerant control is very necessary when the faults of the power converter occur in the system.

Disclosure of Invention

The invention aims to provide a fault-tolerant control method for the open circuit fault of a switched reluctance motor, which has low cost, can effectively carry out fault-tolerant control when the open circuit fault occurs in a power conversion device, and ensures that the performance of a motor system is basically unchanged when the motor system is operated normally so as to solve the problems in the background art.

In order to achieve the purpose, the invention provides the following technical scheme:

the fault-tolerant control method for the open circuit fault of the switched reluctance motor is realized by a three-phase four-leg switched reluctance motor fault-tolerant control system, the three-phase four-leg switched reluctance motor fault-tolerant control system comprises a three-phase switched reluctance motor, a direct-current power supply and a four-leg inverter, windings are in a star connection mode, and neutral points of the windings are connected with a fourth leg.

The control method comprises the following steps:

a. when a certain switch tube has an open circuit fault:

(1) when the switching tube of any bridge arm of the driving circuit is broken, specifically when the lower tube S6 of the third bridge arm is broken, the switching angle of a fault tube signal is adjusted and the signal is transmitted to the lower tube of the fourth bridge arm to be conducted so that A, B two-phase current flows;

(2) regulating the signal switching angle of the fault tube again and transmitting the signal to another healthy switching tube S5 of the fault bridge arm to generate a current which has the opposite direction to the original C-phase current and has the same value as the original C-phase current so as to ensure that the output torque before and after the fault is unchanged;

(3) energization pattern change of field current to A⁺C⁺、A⁺B^-、B^-C⁺、C⁺A^-、A^-B⁺、B⁺C⁺And completing fault-tolerant control.

b. When the switch tubes on two different bridge arms have open circuit faults:

(1) when the switching tubes of two different bridge arms of the driving circuit are in an open circuit condition, specifically when the switching tubes of S3 and S6 are in an open circuit condition, adjusting a signal switching angle of a fault tube S3 and transmitting the signal switching angle to a fourth bridge arm upper tube S7, and adjusting a signal switching angle of a fault tube S6 and transmitting the signal switching angle to a fourth bridge arm lower tube S8;

(2) then adjusting the signal switching angle of the fault tube S3 and transmitting the signal switching angle to the healthy switching tube S4 of the same bridge arm, and similarly transmitting the signal switching angle of S6 to the healthy switching tube S5 of the same bridge arm;

(3) energization pattern change of field current to A⁺C⁺、A⁺B^-、B^-C⁺、C⁺A^-、A^-B^-、B^-C⁺And completing fault-tolerant control.

Compared with the prior art, the invention has the beneficial effects that: the fault-tolerant control method not only can carry out fault-tolerant control on the broken circuit of a single switching tube, but also can carry out fault-tolerant control on the broken circuits of any two tubes which are not on the same bridge arm, thereby ensuring that the performance of a motor system is basically unchanged when the motor system is operated normally; the circuit has the advantages of simple structure, convenient wiring and high winding utilization rate, effectively realizes fault-tolerant operation of the power conversion device after the open circuit fault occurs, and improves the reliability of the system.

Drawings

In order to facilitate understanding for those skilled in the art, the present invention will be further described with reference to the accompanying drawings.

FIG. 1 shows a diagram of a two-phase excited switched reluctance motor system during normal operation A⁺C^-The current in the power-on mode flows in the graph.

FIG. 2 shows fault-tolerant control A after an open circuit fault occurs in the S6 tube⁺C⁺The current in the power-on mode flows in the graph.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1-2, in an embodiment of the present invention, a fault-tolerant control method for an open circuit fault of a switched reluctance motor is implemented by a fault-tolerant control system of a three-phase four-leg switched reluctance motor, where the fault-tolerant control system of the three-phase four-leg switched reluctance motor includes a three-phase switched reluctance motor, a dc power supply, and a four-leg inverter, windings are in a star connection, and a neutral point of the windings is connected to a fourth leg, and the fault-tolerant control method includes the following steps:

a. when a certain switch tube has an open circuit fault:

(1) when the switching tube of any bridge arm of the driving circuit is broken, particularly when the switching tube of the third bridge arm is broken by S6, the switching angle of the signal of the fault tube is adjusted and the signal is transmitted to the fourth bridge arm lower tube to be conducted so that A, B two-phase current flows;

(2) regulating the signal switching angle of the fault tube again and transmitting the signal to another healthy switching tube S5 of the fault bridge arm to generate a current which has the opposite direction to the original C-phase current and has the same value as the original C-phase current so as to ensure that the output torque before and after the fault is unchanged;

(3) energization pattern change of field current to A⁺C⁺、A⁺B^-、B^-C⁺、C⁺A^-、A^-B⁺、B⁺C⁺And completing fault-tolerant control.

b. When the switch tubes on two different bridge arms have open circuit faults:

(1) when the switching tubes of two different bridge arms of the driving circuit are in an open circuit condition, specifically when the switching tubes of S3 and S6 are in an open circuit condition, adjusting a signal switching angle of a fault tube S3 and transmitting the signal switching angle to a fourth bridge arm upper tube S7, and adjusting a signal switching angle of a fault tube S6 and transmitting the signal switching angle to a fourth bridge arm lower tube S8;

(2) then adjusting the signal switching angle of the fault tube S3 and transmitting the signal switching angle to the healthy switching tube S4 of the same bridge arm, and similarly transmitting the signal switching angle of S6 to the healthy switching tube S5 of the same bridge arm;

(3) energization pattern change of field current to A⁺C⁺、A⁺B^-、B^-C⁺、C⁺A^-、A^-B^-、B^-C⁺And completing fault-tolerant control.

The following specific analysis is performed when the switch tube has an open circuit fault:

a. when an open-circuit fault occurs in a certain switching tube (S6:

the three-phase four-bridge arm switched reluctance motor fault-tolerant control system adopts a star connection mode, and the neutral point of the three-phase four-bridge arm switched reluctance motor fault-tolerant control system is connected with the fourth switchThe bridge arms are used for exciting the two-phase windings of the motor at any time, the currents are opposite, and the exciting currents can be divided into six power-on modes A⁺C^-、A⁺B^-、B^-C⁺、C⁺A^-、A^-B⁺、B⁺C^-Taking the power-on mode as an example, when the switching tubes S1 and S6 are simultaneously turned on, the current flows from the positive pole of the dc bus voltage Udc, through the power switching tube S1, the a-phase winding, the C-phase winding and the power switching tube S6, and finally returns to the negative pole of the dc bus voltage Udc, as shown in fig. 1, A, C two phases work simultaneously, and the motor works at a time when the switching tubes S1 and S6 are simultaneously turned on⁺C^-In the power-on mode, the linear torque expression of the switched reluctance motor is as follows:

when any bridge arm switch tube of the driving circuit has an open-circuit fault, particularly taking the open-circuit fault of the switch tube S6 as an example, because of the fault of the S6 tube, six power-on modes A⁺C^-、A⁺B^-、B^-C⁺、C⁺A^-、A^-B⁺、B⁺C^-And the medium current returns to the electrifying mode A of the negative pole of the direct current bus voltage Udc through the S6 pipe⁺C^-、B⁺C^-The work is stopped, no output torque exists in the work, the direct current bus voltage is charged to A, B phase windings and is released in the next electrifying mode, large torque fluctuation and large rotating speed fluctuation are caused, and the system is prone to running disorder.

From (1), the output torque of the switched reluctance motor is only related to the square of the current on the premise that the change of the rotating speed is not large, and the following fault-tolerant control ideas are provided aiming at the characteristics of the open circuit fault:

s1: in the fault electrifying mode, the A, B phase current can return to the negative pole of the DC bus voltage, and the torque fluctuation caused after charging and discharging is eliminated;

s2: and generating a reverse equivalent current on the fault phase to ensure that the output torque is unchanged before and after the fault.

The method comprises the following specific steps:

firstly, adjusting the switching angle of a signal of a fault tube S6 and transmitting the signal to a lower tube of a switched-on fourth bridge arm to enable the current of a A, B two-phase winding to return to the negative pole of the voltage of the direct-current bus; secondly, adjusting a signal switching angle of the fault tube, transmitting the signal to another healthy switching tube S5 of the fault bridge arm, and superposing the signal on the original signal of the S5 switching tube to generate a current which has the opposite direction to the original C-phase current and has the same value as the original C-phase current so as to ensure that the output torque before and after the fault is unchanged; finally, the original work-stopping power-on mode is changed into a working power-on mode by the fourth bridge arm, and the power-on mode of the exciting current is changed into A⁺C⁺、A⁺B^-、B^-C⁺、C⁺A^-、A^-B⁺、B⁺C⁺And completing fault-tolerant control.

b. When the switch tubes on two different bridge arms have open circuit faults (the open circuit faults of the two tubes S3 and S6):

the whole idea is the same as the scheme a: the method comprises the following steps of conducting the current which cannot flow by means of the fourth bridge arm, and simultaneously generating a current with a reverse equivalent value by means of another healthy tube of the fault phase bridge arm to ensure that the output torque is basically unchanged before and after the fault, wherein the method comprises the following specific steps:

specifically, taking the example that two tubes S3 and S6 have an open circuit fault, firstly, the switching angle of a signal of a fault tube S3 is adjusted and transmitted to the upper tube S7 of the fourth bridge arm, and the switching angle of a signal of a fault tube S6 is adjusted and transmitted to the lower tube S8 of the fourth bridge arm; secondly, adjusting a signal switching angle of a fault tube S3 and transmitting the signal switching angle to a healthy switching tube S4 of the same bridge arm, and similarly, adjusting a switching angle of an S6 signal and transmitting the signal switching angle to a healthy switching tube S5 of the same bridge arm; finally, the energizing pattern of the exciting current is changed to A⁺C⁺、A⁺B^-、B^-C⁺、C⁺A^-、A^-B^-、B^-C⁺And completing fault-tolerant control.

Although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that various changes in the embodiments and/or modifications of the invention can be made, and equivalents and modifications of some features of the invention can be made without departing from the spirit and scope of the invention.