阅读说明：本技术 一种适用于工业控制系统的交直流冗余供电系统 (Alternating current-direct current redundant power supply system suitable for industrial control system ) 是由 焦力刚 张华军 金全 戴宣 梁传龙 于 2021-09-06 设计创作，主要内容包括：本发明公开了一种适用于工业控制系统的交直流冗余供电系统,所述系统包括：电源输入模块、电源转换模块、二极管模块和输出模块,所述电源输入模块接入直流电源和交流电源,所述电源转换模块将交流电源转换为直流输出,将两路电源接入所述二极管模块形成两路冗余供电,通过输出模块进行电压输出。本发明解决了现有供电系统不稳定导致整体机组存在安全风险的问题。(The invention discloses an alternating current-direct current redundant power supply system suitable for an industrial control system, which comprises: the power supply comprises a power supply input module, a power supply conversion module, a diode module and an output module, wherein the power supply input module is connected into a direct current power supply and an alternating current power supply, the power supply conversion module converts the alternating current power supply into direct current output, two power supplies are connected into the diode module to form two paths of redundant power supplies, and voltage output is carried out through the output module. The invention solves the problem that the existing power supply system is unstable, so that the whole unit has safety risk.)

1. An ac-dc redundant power supply system suitable for use in an industrial control system, said system comprising: the power supply comprises a power supply input module, a power supply conversion module, a diode module and an output module, wherein the power supply input module is connected into a direct current power supply and an alternating current power supply, the power supply conversion module converts the alternating current power supply into direct current output, two power supplies are connected into the diode module to form two paths of redundant power supplies, and voltage output is carried out through the output module.

2. The ac-dc redundant power supply system suitable for use in an industrial control system of claim 1, wherein said power conversion module comprises: the device comprises an isolation transformer, a bridge rectifier, an electrolytic capacitor and a voltage-stabilizing current-limiting detector, wherein the isolation transformer is connected with the bridge rectifier, the bridge rectifier is connected with the electrolytic capacitor, the electrolytic capacitor is connected with the voltage-stabilizing current-limiting detector, and the output end of the voltage-stabilizing current-limiting detector is connected with the capacitor in parallel and then outputs voltage.

3. The ac-dc redundant power supply system suitable for industrial control systems according to claim 2, wherein the primary side of the isolation transformer is connected to 220V ac power, and after the two transformer coils are transformed, the secondary side of the single isolation transformer outputs 70V ac power.

4. The system of claim 2, wherein the bridge rectifier is connected in parallel with the secondary side of the isolation transformer to convert ac power to dc power via the bridge rectifier.

5. The AC-DC redundant power supply system suitable for industrial control systems according to claim 2, wherein said electrolytic capacitor is connected in parallel with the output of the bridge rectifier and is rectified by filtering through the electrolytic capacitor.

6. The ac-dc redundant power supply system suitable for industrial control systems according to claim 2, wherein said voltage stabilizing current limiting detector is connected in parallel across the electrolytic capacitor, and the voltage stabilizing current limiting detector is controlled by PWM.

7. The AC-DC redundant power supply system suitable for the industrial control system as claimed in claim 2, wherein the output end of said voltage-stabilizing current-limiting detector is connected with a capacitor in parallel to output 66V DC.

8. The system of claim 1, wherein the voltage converted by the power conversion module forms one input voltage, and the other input voltage is supplied by the original 132V dc power supply and is input to the diode module.

9. The ac-dc redundant power supply system suitable for use in an industrial control system of claim 1, wherein said diode module comprises two sets of diodes with opposite polarities to form a two-way power supply.

Technical Field

The invention relates to the field of industrial measurement and control, in particular to an alternating current-direct current redundant power supply system suitable for an industrial control system.

Background

The MFT (main fuel trip) is the core content for ensuring the safe operation of the boiler, and when any dangerous working condition which endangers the safe operation of the boiler occurs, the MFT acts, all oil and coal entering a hearth are quickly cut off, so that the safety of the boiler is ensured, and accidents are avoided or further expansion of the accidents is limited.

ETS (turbine emergency trip system) is a safe and reliable protection device equipped for the operation of large-scale power plants, which enables the turbine to be automatically shut down to protect the safety of the plant in the presence of certain dangerous conditions that may cause damage to the plant.

In order to effectively improve the reliability of the MFT/ETS action, the MFT/ETS is designed into soft and hard redundancy. When a tripping condition occurs, the MFT/ETS acts related equipment through software, and simultaneously sends signals to other systems through hardware, namely a tripping relay board, in order to reduce misoperation and prevent behavior, the MFT/ETS signals take 2 out of 3 on the hardware, and the equipment in the whole plant is protected to the maximum extent. When the MFT/ETS occurs, the relay acts, and the related equipment trips through hard wiring, so that the power supply of the MFT/ETS relay needs to be reliable, once a fault occurs, the related equipment cannot be tripped in time, the safe operation of a unit is directly influenced, and major damage is caused to the main equipment and the auxiliary equipment.

According to the requirements of twenty-five counter measures for preventing electric power production accidents, a power supply used by a trip circuit for protecting a machine furnace of a thermal power plant is reliable, and the protection is ensured not to be refused to operate or be operated mistakenly. Most generator set MFT/ETS loops adopt two direct current power supplies to run in parallel through diodes, for example, two electrical 125VDC power supplies to supply power in parallel, as shown in FIG. 3, the anodes of the two power supplies are respectively connected in series with a diode, the cathodes of the two power supplies are respectively connected in series with a diode in reverse phase with the anode, and one power supply is output after automatic high selection of the diodes. According to the working characteristics of the diodes, one of the two direct current power supplies is always in a working state under normal conditions, when the power supply fails, the diode of the other power supply is conducted for a short time to enter the working state, undisturbed switching is realized, and the uninterrupted thermal control power supply is ensured.

However, in the dc power supply system shown in fig. 3, the anodes of the thermal control dc power supplies are the anodes of the two electrical dc power supplies 125VDC connected together through diodes, and the cathodes thereof are connected together through inverting diodes, so that the two dc power supplies form a loop, which is not completely independent, and there is a hidden danger in the safe operation of the unit. As long as the direct current grounding fault occurs in the system structure, no matter where the direct current grounding fault occurs, the two direct current systems can be grounded simultaneously, and the electric grounding line selection device cannot correctly judge the position of the grounding point, so that great difficulty is brought to the work of fault finding and accident handling. Meanwhile, in the process of searching the grounding point, the thermal control power supply has the risk of total loss, more serious consequences can be caused, and the safe operation of the unit is seriously threatened.

Disclosure of Invention

Therefore, the invention provides an alternating current-direct current redundant power supply system suitable for an industrial control system, and aims to solve the problem that the safety risk of the whole unit is caused by instability of the existing power supply system.

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

the invention discloses an alternating current-direct current redundant power supply system suitable for an industrial control system, which comprises: power input module, power conversion module, diode module and output module, power input module inserts 132V DC power supply and 220V AC power supply, power conversion module converts 220V AC power supply into 132V DC output, inserts two way powers diode module forms two way redundant power supplies, carries out voltage output through output module.

Further, the power conversion module includes: the device comprises an isolation transformer, a bridge rectifier, an electrolytic capacitor and a voltage-stabilizing current-limiting detector, wherein the isolation transformer is connected with the bridge rectifier, the bridge rectifier is connected with the electrolytic capacitor, the electrolytic capacitor is connected with the voltage-stabilizing current-limiting detector, and the output end of the voltage-stabilizing current-limiting detector is connected with the capacitor in parallel and then outputs voltage.

Furthermore, 220V ac is connected to the primary side of the isolation transformer, and after voltage transformation is performed on the two transformer coils, 70V ac is output from the secondary side of a single isolation transformer.

Further, the bridge rectifier is connected in parallel with the secondary side of the isolation transformer, and the bridge rectifier converts alternating current into direct current.

Furthermore, the electrolytic capacitor is connected in parallel with the output end of the bridge rectifier, and filtering rectification is performed through the electrolytic capacitor.

Furthermore, the voltage-stabilizing current-limiting detector is connected in parallel at two ends of the electrolytic capacitor and is controlled by PWM.

Furthermore, the output end of the voltage stabilizing and current limiting detector is connected with a capacitor in parallel and then outputs 66V direct current.

Furthermore, the voltage converted by the power conversion module forms one path of input voltage, and the other path of input voltage is supplied by the original 132V direct current power supply and is input into the diode module.

Furthermore, the diode module comprises two groups of diodes with opposite polarities to form two paths of power supply redundant power supplies.

The invention has the following advantages:

the invention discloses an alternating current-direct current redundant power supply system suitable for an industrial control system, which changes two paths of 132V DC power supply of an MFT/ETS relay panel into one path of power supply maintaining original design, and the other path of power supply is removed, replaced by 220V AC access, converted into 132V DC output through a switching power supply, an isolation transformer and an inverter as shown in figure 3, and then merged into a diode to realize the two paths of power supply redundant power supply. The MFT/ETS control cabinet power supply is changed into a power supply redundancy mode of supplying power by using direct current and alternating direct current together, so that the safe redundant power supply of the power supply can be ensured, the physical isolation of two paths of power supplies can be realized, and the condition that the grounding of one path of power supply does not influence the normal power supply of the other path of power supply is ensured. The power supply configuration is optimized, the power supply of the ETS/MFT disk is prevented from being lost due to other grounding points, so that the main protection of a boiler and a turbine is lost, and the stability and the anti-interference capability of a direct-current power supply system of a #2 unit are improved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below. It should be apparent that the drawings in the following description are merely exemplary, and that other embodiments can be derived from the drawings provided by those of ordinary skill in the art without inventive effort.

The structures, ratios, sizes, and the like shown in the present specification are only used for matching with the contents disclosed in the specification, so as to be understood and read by those skilled in the art, and are not used to limit the conditions that the present invention can be implemented, so that the present invention has no technical significance, and any structural modifications, changes in the ratio relationship, or adjustments of the sizes, without affecting the effects and the achievable by the present invention, should still fall within the range that the technical contents disclosed in the present invention can cover.

Fig. 1 is a schematic diagram of a redundant configuration of a dc + ac dc power supply of an ac/dc redundant power supply system suitable for an industrial control system according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of a 220VAC to 125VDC power isolation switch provided by an embodiment of the present invention;

fig. 3 is a schematic diagram of a conventional two-way dc power supply redundancy configuration according to an embodiment of the present invention.

Detailed Description

The present invention is described in terms of particular embodiments, other advantages and features of the invention will become apparent to those skilled in the art from the following disclosure, and it is to be understood that the described embodiments are merely exemplary of the invention and that it is not intended to limit the invention to the particular embodiments disclosed. 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.

Examples

The embodiment discloses an alternating current-direct current redundant power supply system suitable for an industrial control system, the system includes: power input module, power conversion module, diode module and output module, power input module inserts 132V DC power supply and 220V AC power supply, power conversion module converts 220V AC power supply into 132V DC output, inserts two way powers diode module forms two way redundant power supplies, carries out voltage output through output module.

The power conversion module includes: the device comprises an isolation transformer, a bridge rectifier, an electrolytic capacitor and a voltage-stabilizing current-limiting detector, wherein the isolation transformer is connected with the bridge rectifier, the bridge rectifier is connected with the electrolytic capacitor, the electrolytic capacitor is connected with the voltage-stabilizing current-limiting detector, and the output end of the voltage-stabilizing current-limiting detector is connected with the capacitor in parallel and then outputs voltage.

220V alternating current is connected to the primary side of the isolation transformer, after voltage transformation is carried out on the two transformer coils respectively, 70V alternating current is output from the secondary side of a single isolation transformer, the two transformer coils are connected in parallel, and voltage transformation is carried out on the two transformer coils in a divided mode. The bridge rectifier is connected with the secondary side of the isolation transformer in parallel, and the bridge rectifier converts alternating current into direct current.

The bridge rectifier uses four diodes, butted two by two. The positive half part of the input sine wave is conducted by two pipes to obtain positive output; when the negative half part of the sine wave is input, the other two tubes are conducted, and because the two tubes are reversely connected, the output still obtains the positive half part of the sine wave. The bridge rectifier doubles the utilization efficiency of the input sine wave as compared with the half-wave rectification. Bridge rectification is the first step in converting ac power to dc power. The bridge rectifier is formed by bridge connection of a plurality of rectifier diodes and external insulation plastic packaging, and the high-power bridge rectifier is packaged by adding a metal shell outside an insulation layer to enhance heat dissipation. The bridge rectifier has multiple varieties, excellent performance, high rectification efficiency and good stability, the maximum rectification current is from 0.5A to 50A, and the highest reverse peak voltage is from 50V to 1000V.

The electrolytic capacitor is connected in parallel with the output end of the bridge rectifier, the filter rectification is carried out through the electrolytic capacitor, the electrolytic capacitor is 10000 muF, the electrolytic capacitor is used as a filter capacitor in a direct current power supply circuit, the anode (positive pole) of the electrolytic capacitor is connected with the positive pole end of the power supply voltage, and the cathode (negative pole) of the electrolytic capacitor is connected with the negative pole end of the power supply voltage. The voltage-stabilizing current-limiting detector is connected in parallel at two ends of the electrolytic capacitor and realizes voltage-stabilizing current-limiting through PWM control. The overload protection function is to effectively protect the DC-DC converter from damage due to overheating in case of overload of the load, i.e. mainly to control the overload current (input current) of the power MOSFET. Due to different electrical loads, the overload protection function is required to be different. If the satellite control system requires that the DC-DC converter cannot be powered off after overload, current limiting protection is adopted; payload systems require that the DC-DC converter can be powered down after an overload, so that cutoff protection is taken. The output end of the voltage-stabilizing current-limiting detector is connected with a capacitor in parallel and then outputs 66V direct current.

The voltage converted by the power conversion module forms one path of input voltage, and the other path of input voltage is supplied by the original 132V direct-current power supply and is input into the diode module; the diode module comprises two groups of diodes with opposite polarities to form two paths of power supply redundant power supplies.

In the embodiment, a 300MW coal-fired power plant MFT/ETS tripping relay disk 125VDC power supply is taken as an example, and a No. 2 unit MFT/ETS control cabinet is originally designed to supply power by two paths of 125VDC power. Two routes DC power supply are got respectively from No. 2 unit 125V DC2A section and 125V DC2B section and are passed through the diode and realize redundant control, seem authoritative perfect design but have very big potential safety hazard in operation, when 2A, 2B arbitrary one section ground point appears, will directly transmit for DC power supply unit through diode return circuit, lead to two routes power whole ground connection, the while has serious voltage excursion, this hidden danger can lead to my factory MFT ETS relay control panel to lose the control power, boiler and turbine main protection are invalid, and threaten the whole DC power supply system safety and stability of #2 unit.

The power supply of two 132V DC power supplies of an MFT/ETS relay panel is changed into one path of power supply for maintaining the original design, the other path of power supply is removed and is changed into 220V AC access, the power supply is converted into 132V DC output through a switching power supply, an isolation transformer and an inverter, and the power supply is merged into a diode to realize redundant power supply of the two paths of power supplies.

The MFT/ETS control cabinet power supply is changed into a power supply redundancy mode of supplying power by using direct current and alternating direct current together, so that the safe redundant power supply of the power supply can be ensured, the physical isolation of two paths of power supplies can be realized, and the condition that the grounding of one path of power supply does not influence the normal power supply of the other path of power supply is ensured. The power supply configuration is optimized, the power supply of the ETS/MFT disk is prevented from being lost due to other grounding points, so that the main protection of a boiler and a turbine is lost, and the stability and the anti-interference capability of a direct-current power supply system of a #2 unit are improved.

Although the invention has been described in detail above with reference to a general description and specific examples, it will be apparent to one skilled in the art that modifications or improvements may be made thereto based on the invention. Accordingly, such modifications and improvements are intended to be within the scope of the invention as claimed.