KR20020058940A - Fault-tolerant levitation control system for ems maglev vehicle - Google Patents

Abstract

PURPOSE: A fault-tolerant levitation control system is provided to achieve an improved reliability for vehicle operation by maintaining levitation and travel operation in a stable manner even upon occurrence of a fault in one of two choppers. CONSTITUTION: A fault-tolerant levitation control system comprises a levitation controller(30) for generating a levitation control signal through a pulse width modulation; first and second choppers(32,34) connected in parallel to the levitation controller, and which receive the levitation control signal, respectively; first and second electromagnets(36,38) connected in parallel to the output ports of the first and second choppers, respectively; and an acceleration sensor(40) arranged between the levitation controller and first and second electromagnets.

Description

FAULT-TOLERANT LEVITATION CONTROL SYSTEM FOR EMS MAGLEV VEHICLE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a levitation control system, and more particularly, to a levitation control system for a phase-conductive magnetic levitation train and to a levitation control system having a fault-tolerant function.

Maglev trains are expected to serve as new transportation facilities. For example, it is known that a phase-conduction maglev train has a limit to maintain a stable injury state only through feedback control, in which the principle of injury is continuous. The levitation control system currently used in the magnetically levitated train using the phase conduction floating method uses a plurality of choppers (power converters that control the current flowing through the electromagnets and maintains the floating state) and a plurality of electromagnets.

Flotation control systems mounted on phase-conducting maglev trains typically consist of a float controller, a number of choppers, electromagnets and sensors. One maglev train usually consists of three bogies. The float control system has a structure with eight electromagnets and corresponding choppers in one bogie. Each corner of the view is then assigned two electromagnets and corresponding choppers.

The conventional flotation control system having such a structure has a structure in which only one chopper is connected to one electromagnet so that each electromagnet operates normally only when its chopper is normally operated.

FIG. 1 is a circuit diagram illustrating a typical connection relationship between a chopper and an electromagnet provided at each corner of a bogie in a general flotation control system applied to a phase-conductive maglev train, and FIG. 2 is a pulse width modulation input to the two choppers of FIG. 1. A diagram showing a phase difference of a (PWM) signal.

Referring to FIG. 1, a floating control system mounted on a general phase-conducting maglev train includes a plurality of choppers 10 and 20 and electromagnets 12 and 22. Reference numerals S11, S12, S21, S22 are switching elements, and may be constituted by, for example, IGBTs. Reference numerals D11, D12, D21, and D22 denote fast recovery diodes from power sources V10 and V20 to the electromagnets 12 and 22 when the switching elements S11, S12, S21, and S22 corresponding to the fast recovery diodes are turned off. Allow current to continue to flow.

As described above, the floating control system has one electromagnet connected to one chopper alone, and a voltage V and a current I of a power source corresponding to one electromagnet are applied. As shown in FIG. 2, the two choppers 10 and 20 are provided with a 10 KHz PWM signal input with a phase difference of 180 degrees from each other. Thus, if one chopper fails, the electromagnet cannot be used, so the levitation system is likely to be unstable. Therefore, since the chopper failure is directly related to the instability of the flotation system, the credibility of the chopper should be made as large as possible to improve the reliability of the entire flotation system.

A graph showing a change in reliability of a chopper and an electromagnet over time in the flotation control system as described above is shown in FIG. 3. The graph shown in the drawing shows the reliability of the chopper and the electromagnet when the failure rate of each chopper and the electromagnet is assumed to be 10 ⁻⁵ .

Referring to the drawings, the horizontal axis represents reliability, and the vertical axis represents time at which the reliability can be guaranteed. The value of the horizontal axis is expressed as a reliability index, which is defined as representing the number of "9" in reliability values such as 0.99, 0.999, ..., 0.999999999. For example, a confidence index value of 5 on the horizontal axis means a value of 0.99999 reliability, and the horizontal axis is expressed in logarithm. At this time, the lines marked with "*" and "o" in the drawings represent the reliability of the module and the vehicle, respectively, it can be seen that the maximum reliability of about 0.999 for 10 hours driving.

In the conventional magnetic levitation system as described above, only one chopper is connected to one electromagnet, so that if the chopper fails and no more normal current can flow, the electromagnet cannot be used for floating control. That is, there is a disadvantage that the floating action becomes unstable due to the chopper failure, which is impossible to operate even by one of the 24 choppers installed in one magnetic levitation vehicle. Reliability and availability are very low.

Therefore, in order to maintain stable control characteristics, it is necessary to devise a control structure that does not significantly affect the control characteristics even if the chopper and the electromagnet fail. One way to solve this problem is to increase the reliability of the chopper, but it is very important to make the reliability of the chopper using microprocessors and power semiconductors as reliable as other mechanical components. Not only is it difficult, but the economics to achieve it are also known to be negative.

Accordingly, an object of the present invention is to solve the above-mentioned problems and to provide a injury control system having a fault-tolerant function for a phase-conduction maglev train capable of stable injury control even in the event of a chopper abnormality. It is.

1 is a circuit diagram showing a typical connection between a chopper and an electromagnet provided at each corner of a bogie in a general flotation control system applied to a phase-conductive maglev train;

2 is a diagram illustrating a phase difference of a PWM signal input to two choppers of FIG. 1;

3 is a graph showing a change in reliability of the chopper and the electromagnet of FIG. 1 with time;

Figure 4 is a block diagram showing the configuration of a failure prevention injury control system for a phase-conduction maglev train according to the present invention;

FIG. 5 is a diagram illustrating a phase difference of a PWM signal input to two choppers in the floating control system of FIG. 4; FIG.

6 is a circuit diagram illustrating a connection structure between an electromagnet and a chopper connected in series in the flotation control system of FIG. 4;

7 is a circuit diagram illustrating a connection structure between an electromagnet and a chopper connected in parallel in the flotation control system of FIG. 4;

FIG. 8 is a view for explaining an operation state when one chopper of the injury control system in FIG. 6 fails; FIG.

9 is a graph showing a change in reliability over time of the injury control system of FIG.

FIG. 10 is a graph showing the ratio of the reliability guarantee time for the conventional injury control system of the injury control system of FIG.

According to an aspect of the present invention for achieving the object of the present invention as described above, the levitation control system for a phase-conduction magnetic levitation train includes: a levitation controller for generating a levitation control signal with a pulse width modulation signal; First and second choppers connected in parallel to the floating controller to receive the floating control signal, respectively; First and second electromagnets connected in parallel to output ends of the first and second choppers; And an acceleration sensor configured between the flotation controller and the first and second electromagnets.

According to another aspect of the present invention, a flotation control system for a phase-conduction maglev train includes: a flotation controller for generating a flotation control signal with a pulse width modulated signal; First and second choppers connected in parallel to the floating controller to receive the floating control signal, respectively; First and second electromagnets connected in series with the output terminals of the first and second choppers; And an acceleration sensor configured between the flotation controller and the first and second electromagnets.

(Example)

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Figure 4 is a block diagram showing the configuration of a failure prevention injury control system for a phase-conduction maglev train according to the present invention.

Referring to the drawings, the injury control system according to the present invention has a fault tolerant function, which is provided from the injury controller 30, the injury controller 30 for generating a injury control signal for magnetic injury First and second choppers 32 and 34 for modulating the floating control signal, and first and second electromagnets 36 and 38 for receiving signals from the first and second choppers 32 and 34 to generate magnetic force. ) And an acceleration sensor 40 which detects the magnetic force generation of the first and second electromagnets 36 and 38 and feeds it back to the lift controller 30. In this floating control system, two choppers and two electromagnets are connected to each other to realize a failure prevention function. The two electromagnets are connected in series or in parallel, and the choppers are always connected in parallel.

The floating controller 30 is composed of a digital processor, and between the first and second electromagnets 36 and 38 and a rail (not shown) using a signal obtained by sampling the acceleration sensor 40 at a control frequency of 4 KHz. Generate a float control signal to keep the void constant. This floating control signal is converted into a 10 kHz PWM signal, that is, a square wave in the form of a signal that can be used by the first and second choppers 32 and 34, so that the same as the first and second choppers 32 and 34 without phase delay. Is entered. FIG. 7 is a diagram illustrating a phase difference of a PWM signal input to two choppers in the floating control system of FIG. 4. The PWM signal is input in the same phase as the two first and second electromagnets 36 and 38 are not independent but are connected in parallel. On-time of the chopper is determined in proportion to the flotation control signal sent from the flotation controller 30, and currents of the first and second electromagnets 36 and 38 are determined in proportion to the on-time. do.

6 is a circuit diagram illustrating a connection structure between an electromagnet and a chopper connected in series in the flotation control system of FIG. 4, and FIG. 7 is a circuit diagram illustrating a connection structure between an electromagnet and a chopper connected in parallel in the flotation control system of FIG. 4.

Referring to the drawings, reference numerals S31, S32, S41, and S42 are switching elements and may be configured, for example, with IGBTs. Reference numerals D31, D32, D41, and D42 are fast recovery diodes, and when the switching elements S31, S32, S41, and S42 corresponding to each other are turned off, power to the first and second electromagnets 36 and 38 is turned off. The current provided from V30 and V40 continues to flow.

Each current flowing from the first and second choppers 32 and 34 to the first and second electromagnets 36 and 38 is referred to as I, and the voltage across the first and second electromagnets 36 and 38 is V. The resistance of the first and second electromagnets 36 and 38 is referred to as R. As shown in FIG. 6, when the first and second electromagnets 36 and 38 are connected in series, the resistances of the entire first and second electromagnets 36 and 38 are 2R, and the first and second choppers ( 32 and 34 have a voltage of 2 V and a current of 0.5 I, so that a current of I flows in each of the first and second electromagnets 36 and 38. As shown in FIG. 7, when the first and second electromagnets 36 and 38 are connected in parallel, the total resistance is 0.5 R, and a current of I is applied to one of the first and second electromagnets 36 and 38. In order to flow, the voltage of each of the first and second choppers 32 and 34 becomes V, so that the power is the same. Thus, the power provided to the first and second electromagnets 36 and 38 from the first and second choppers 32 and 34 respectively becomes VI.

FIG. 8 is a view for explaining an operation state when one chopper of the injury control system in FIG. 6 fails.

Referring to the drawing, when a failure occurs in the second chopper 34, the output current from the failed second chopper 34 becomes 0, and the first chopper 32 automatically turns the first and second electromagnets 36 into consideration. , 38) outputs a current of 2I in order to flow the current I. Thus, the magnetic levitation system can perform a stable function as a whole.

FIG. 9 is a graph showing a change in reliability over time of the injury control system of FIG. 4, and FIG. 10 is a graph showing a ratio of the reliability guarantee time of the conventional injury control system of the injury control system of FIG. 4.

Referring to FIG. 9, it is a graph showing the guaranteed time against the reliability index in the flotation control system of the present invention, and shows the reliability of the chopper and the electromagnet when the failure rate of each chopper and the electromagnet is assumed to be 10 ⁻⁵ . As shown, it can be seen that the reliability for the 10-hour operation is significantly improved than the conventional one so that a value of 0.9999999 or more is guaranteed. That is, the probability that a failure occurs during 10 hours of continuous operation is 1/1000 in the existing system structure, compared with 1/10000000 in the system structure of the present invention.

Referring to FIG. 10, the vertical axis is a time value guaranteed by the system of the present invention divided by time values guaranteed by the existing system. The ratio increases exponentially with more stringent reliability requirements. For example, if the required reliability is 0.999999999, the proposed system structure is about 2 × 10 ⁵ times that of the existing structure. It will increase the reliability. Table 1 below is a result of calculating the availability for the case of repair rate (repair rate) once per 12 hours.

Kinds Availability if a module Availability for vehicles The old way 0.999760058 0.9971244927253465 Manner of the invention 0.999999971 0.999999652000056

As can be seen in Table 1, the unavailable time when the phase-conducting maglev train equipped with the injury control system of the present invention runs 10,000 hours is about 29 hours in a conventional vehicle. In the vehicle of the present invention, the availability is increased within 0.0035 hours.

The above-described floating control system of the present invention is applicable to the chopper and the electromagnet system of the floating system of the phase-conducting magnetic levitation train, and connects two choppers and two electromagnets in parallel or in series at one corner of the bogie, respectively. Injury control system with fault protection can be implemented. In addition, the chopper can be easily used as it can use a chopper of the same capacity as before.

As described above, the configuration and operation of the injury control system according to a preferred embodiment of the present invention has been shown in accordance with the above description and drawings, but this is merely described, for example, without departing from the spirit of the present invention. It will be appreciated by those skilled in the art that various changes and modifications are possible.

According to the floating control system of the present invention, since two choppers are connected in parallel to two electromagnets connected in series or in parallel, even when a failure occurs in any one of the two choppers, the state of injury and running is stable. It greatly expands the availability of the floating system of the phase-conducting maglev train and improves the reliability of operation.

Claims (2)

In a flotation control system for a phase-conduction maglev train: A float controller for generating a float control signal with a pulse width modulated signal; First and second choppers connected in parallel to the floating controller to receive the floating control signal, respectively; First and second electromagnets connected in parallel to output ends of the first and second choppers; And And an acceleration sensor configured between said injury controller and said first and second electromagnets. In a flotation control system for a phase-conduction maglev train: A float controller for generating a float control signal with a pulse width modulated signal; First and second choppers connected in parallel to the floating controller to receive the floating control signal, respectively; First and second electromagnets connected in series with the output terminals of the first and second choppers; And And an acceleration sensor configured between said injury controller and said first and second electromagnets.