CN102801140A - Marine high-power AC-DC (alternating current-direct current) converter based on thyristor - Google Patents

Abstract

The invention relates to the field of industrial instruments and meters, in particular to a thyristor-based marine high-power AC-DC converter with fast protection speed and various forms. Each output end of the AC side of the AC-DC converter is connected to a current transformer and a voltage transformer. The current transformer and the voltage transformer are respectively connected to the input end of the electronic protection control board, and input signals to the electronic protection control board, and the electronic protection control The board monitors circuit faults in real time, controls the protection switch and the alarm buzzer. Compared with the existing technology, it has carried out more comprehensive monitoring of short circuit, overvoltage, overload, overcurrent, and lack of phase faults, and applied the protection method of electronic protection control board and protection components to make the AC-DC converter Get more accurate and faster protection.

Description

A Thyristor-Based Marine High-Power AC-DC Converter

technical field

The invention relates to the field of industrial instruments and meters, in particular to a thyristor-based marine high-power AC-DC converter with fast protection speed and various forms. the

Background technique

AC-DC converters work in a high-power environment, and failures are inevitable. The composition of traditional AC-DC converter protection devices in my country is relatively simple. The fault types of protection are only protection against overcurrent, overvoltage and short circuit. The protection tools used are only fast fuses, varistors, and resistance-capacitance buffers. and other components for protection. Traditional protection devices cannot monitor real-time voltage and current values, and cannot check accurate overvoltage and overcurrent values when a fault occurs. Therefore, the traditional protection device cannot protect the AC-DC converter very accurately, and can only be estimated based on experience. the

In the 2008 annual meeting of the Metallurgical Branch of the China Metrology Association, a simple analysis of the causes of overvoltage and overcurrent in the thyristor rectifier DC power supply system was disclosed in the document "Thyristor Rectifier Power Supply Circuit Protection Circuit Design", and countermeasures were designed. . the

Its composition is relatively simple. The overcurrent protection bridge is protected by a fast fuse inside the bridge, and an electronic circuit is used outside the bridge for protection, that is, the current signal is generated by a current transformer and converted into a voltage signal and then generated by a voltage comparator. The over-current trigger signal passes through the trigger to control the relay switch for over-current protection. For overvoltage protection, devices such as surge arresters, varistors, and RC resistance-capacitance absorption are used for protection. Its disadvantage is that operators cannot monitor real-time voltage and current values, and cannot protect against phase loss. the

Contents of the invention

The purpose of the present invention is to provide a thyristor-based marine high-power AC-DC converter with more timely protection speed and more protection types. the

The purpose of the present invention is achieved like this:

A marine high-power AC-DC converter based on thyristors. Each output terminal of the AC-DC converter is connected to a current transformer and a voltage transformer. The current transformer and the voltage transformer are respectively connected to the electronic protection control board. Terminal connection, input signal to the electronic protection control board, the electronic protection control board monitors the circuit fault in real time, controls the protection switch and the alarm buzzer. the

The electronic protection control board is composed of a sampling signal processing module, an analog-to-digital conversion module, a CPU module, a liquid crystal display module, a photoelectric isolation module, a switch output module and an alarm buzzer. The module converts the signal proportionally into a signal that meets the sampling standard of the analog-to-digital conversion module and transmits it to the analog-to-digital conversion module for analog-to-digital conversion. The CPU module obtains the signal transmitted by the analog-to-digital conversion module and performs calculations, and compares it with the rated voltage and current. The comparison result is sent to the photoelectric isolation module, and the photoelectric isolation module drives the optocoupler to output the signal to the digital input and output module, and the digital input and output module controls the relay switch state to complete the alarm of overload, overvoltage, overcurrent and phase loss and protection. the

It also includes a varistor and a resistance-capacitance absorption circuit. Three varistors are connected in star form at each overvoltage on the AC side of the AC-DC converter, and each thyristor in the rectifier bridge of the AC-DC converter is connected in parallel with a resistance-capacitance circuit. In the absorbing circuit, a varistor is connected in parallel with the load on the DC side of the AC-DC converter. the

It also includes a protective switch and a fast fuse. A protective switch and a fast fuse are installed in series on each incoming line of the AC side of the AC-DC converter, and a fast fuse is connected in series with the positive pole of the load on the DC side of the AC-DC converter. fuse. the

The current transformer and the voltage transformer are connected in parallel or in series at the output end of the AC side of the AC-DC converter. the

The sampling signal processing module is composed of a voltage follower connected with an operational comparator, and converts the input signal into a signal that meets the sampling standard of the analog-to-digital conversion module in proportion. the

The switching value output module is composed of a triode connected to a relay. The input signal makes the triode conduct, and the triode controls the switching state of the relay to complete the alarm and protection of the circuit. the

The beneficial effects of the present invention are:

Compared with the existing technology, it has carried out a more comprehensive monitoring of short circuit, overvoltage, overload, overcurrent, and lack of phase faults, and applied the protection method of electronic protection control board and protection components to make the AC-DC converter Get more accurate and faster protection. the

Description of drawings

Fig. 1 is a kind of marine high-power AC-DC converter figure based on thyristor of the present invention;

Fig. 2 is the electronic protection control board hardware block diagram of the present invention;

Figure 3 is a hardware block diagram of the electronic protection control board. the

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and preferred embodiments. the

Embodiment one:

Please refer to Figure 1 for the overall design and protection configuration of the 12-pulse marine high-power AC-DC converter. The first embodiment of the present invention provides a thyristor-based 12-pulse marine high-power AC-DC converter. This AC-DC converter is composed of 12-pulse AC-DC converter, fast fuse, piezoresistor, resistance-capacitance buffer, sensor (current and voltage transformer), electronic protection control board, protection switch and alarm buzzer composition. The electronic protection control board is composed of a signal sampling processing module, an analog-to-digital conversion module, a CPU module, a photoelectric isolation module, a switch output module, and a signal display module. The components and chips that can realize the functions of these modules are welded on a circuit board On, the electronic protection control board is formed. This part provides good protection for the short circuit, overcurrent, overload, overvoltage and phase loss faults encountered by the AC-DC converter during operation. the

In this embodiment, the short-circuit protection is divided into three aspects: the AC side of the AC-DC converter, the bridge and the DC side. On the AC side of the AC-DC converter, a fast fuse is installed in series on each incoming line (FU), the number is 6 in total, and protection switches are installed respectively; inside the rectifier bridge of the AC-DC converter, only one fast fuse (FU) is installed in series next to the thyristor of the lower bridge arm, the total number There are 6 pieces; on the DC side of the AC-DC converter, a fast fuse (FU) is installed in series on the positive pole of the load, and the number is 1 piece. the

In this embodiment, the overvoltage protection adopts a protection mode in which piezoresistive elements, resistance-capacitance buffers and electronic protection control boards cooperate. On the one hand, varistors are used for the overvoltage on the AC side of the AC-DC converter, and the varistor connection methods include star connection and delta connection. In this example, the star connection method is used. The total number of varistors (VDR) is 6. The thyristors in the rectifier bridge of the AC-DC converter are respectively connected in parallel with resistance-capacity absorption circuits, and the number of resistance-capacity absorption circuits (R1-R12, C1-C12) is 12. Install a piezoresistor on the DC side of the AC-DC converter and connect it in parallel with the load. On the other hand, the current voltage transformer (PT) detects the voltage and current values of the converter in real time and transmits the signal to the electronic protection control board. If a fault occurs, the electronic protection control board will start the protection switch and alarm buzzer according to the predetermined program device. the

Overload protection, overcurrent protection and phase loss protection use current and voltage transformers (PT) to detect the current and voltage values of the AC-DC converter and send the signals to the electronic protection control board, and the signals are processed by the modules of the electronic protection control board If it is fed into the protection switch, if there are overcurrent, overload and phase loss faults, the electronic protection control board will start the protection switch and the alarm buzzer according to the predetermined procedure. the

Example two

Please refer to Figure 2 for the overall design and protection configuration of the 6-pulse marine high-power AC-DC converter. The second embodiment of the present invention provides a thyristor-based 6-pulse marine high-power AC-DC converter. Its protection method is the same as that of the 12-pulse high-power AC-DC converter. the

In this embodiment, the short-circuit protection is divided into three aspects: the AC side of the AC-DC converter, the bridge and the DC side. On the AC side of the AC-DC converter, a fast fuse is installed in series on each incoming line ( FU), the number is 3 in total, and protection switches are installed respectively; inside the rectifier bridge of the AC-DC converter, only one fast fuse (FU) is installed in series next to the thyristor of the lower bridge arm, and the total number is 3; on the DC side of the AC-DC converter, a fast fuse (FU) is installed in series on the positive pole of the load, and the number is 1. the

In this embodiment, the overvoltage protection adopts a protection mode in which piezoresistive elements, resistance-capacitance buffers and electronic protection control boards cooperate. On the one hand, the overvoltage on the AC side of the AC-DC converter adopts the varistor star connection mode, and the number of varistors (VDR) is three in total. ; The thyristors in the rectifier bridge of the AC-DC converter are respectively connected in parallel with resistance-capacity absorption circuits, and the number of resistance-capacity absorption circuits (R1-R6, C1-C6) is six. Install a piezoresistor on the DC side of the AC-DC converter and connect it in parallel with the load. On the other hand, the current voltage transformer (PT) detects the voltage and current values of the converter in real time and transmits the signal to the electronic protection control board. If a fault occurs, the electronic protection control board will start the protection switch and alarm buzzer according to the predetermined program device. the

Overload protection, overcurrent protection and phase loss protection use current and voltage transformers (PT) to detect the current and voltage values of the AC-DC converter and send the signals to the electronic protection control board, and the signals are processed by the modules of the electronic protection control board If it is fed into the protection switch, if there are overcurrent, overload and phase loss faults, the electronic protection control board will start the protection switch and the alarm buzzer according to the predetermined procedure. the

Please refer to Figure 3 for the hardware module diagram of the electronic protection control board. The electronic protection control board of the marine high-power AC-DC converter is composed of a signal sampling processing module, an analog-to-digital conversion module, a CPU module, a photoelectric isolation module, a switch output module, and a signal display module. On the corresponding printed circuit board, the leads connected to the outside on the board are drawn out through the plug. First, the current and voltage transformer acquisition signal is processed by the sampling signal processing module. The sampling signal processing module includes module 1 and module 2. Module 1 is used as a voltage follower, and module 2 is used as an operation comparator. The purpose is to convert the input signal to a certain ratio. becomes a signal that satisfies the sampling standard of the analog-to-digital conversion module. Then the signal is sent to the analog-to-digital conversion module for analog-to-digital conversion, and then sent to the CPU module for calculation and comparison with the rated voltage and current values, and at the same time, the voltage and current values are sent to the communication display module for display. After the input signal is calculated and compared, its output signal is sent to the photoelectric isolation module. The photoelectric isolation module is composed of an optocoupler drive and an optocoupler. After driving the optocoupler, the optocoupler will output a signal to the switch input and output module. The switch output module consists of Composed of triode and relay, the signal makes the triode conduct, and the triode controls the switch state of the relay to complete the alarm and protection of overload, overvoltage, overcurrent and phase loss. the

There are many kinds of chips on the electronic protection control board can be selected, as long as the chip can realize the function of the corresponding module. For example, the CPU module can choose many kinds of chips, such as single-chip microcomputer (MCU) series, DSP series, ARM series, FPGA series, etc. The CPU module uses TMS320F2812 DSP chip, which is used as the core controller and digital signal processor of the circuit to complete the protection and monitoring functions of the circuit. the

Claims (7)

1. peculiar to vessel high-power AC-DC converter based on thyristor; It is characterized in that: each output of AC-DC converter AC side connects a current transformer and a voltage transformer; Current transformer, voltage transformer are connected with Electronic Protection control board input respectively; To Electronic Protection control board input signal, the real-time observation circuit fault of Electronic Protection control board, control protection switch and alarm buzzer.

2. a kind of peculiar to vessel high-power AC-DC converter according to claim 1 based on thyristor; It is characterized in that: described Electronic Protection control board is made up of sampled signal processing module, analog-to-digital conversion module, CPU module, LCD MODULE, photoelectric isolation module, switching value output module and alarm buzzer; The sensor acquisition signal is sent to the sampled signal processing module; The sampled signal processing module changes signal in proportion into the signal that satisfies the analog-to-digital conversion module standard for manual sampling and sends analog-to-digital conversion module to carries out analog-to-digital conversion; The CPU module is obtained the laggard row operation of signal that analog-to-digital conversion module transmits; Compare with the electric current and voltage rated value; Comparative result is sent to photoelectric isolation module, and the output signal was accomplished the warning and the protection of overload, overvoltage, overcurrent and phase shortage to the switching value input/output module after photoelectric isolation module drove optocoupler by switching value input/output module control relay switch shape.

3. a kind of peculiar to vessel high-power AC-DC converter according to claim 1 and 2 based on thyristor; It is characterized in that: also comprise piezo-resistance and capacitance-resistance absorption circuit; In three piezo-resistances of the star-like connection in each overvoltage place of AC-DC converter AC side; Capacitance-resistance absorption circuit of each thyristor parallel connection in AC-DC converter rectifier bridge is in the parallelly connected piezo-resistance with load of the DC side of AC-DC converter.

4. a kind of peculiar to vessel high-power AC-DC converter according to claim 3 based on thyristor; It is characterized in that: also comprise protection switch and fast acting fuse; A protection switch of series connection installing and a fast acting fuse on every inlet wire of AC-DC converter AC side are at fast acting fuse of positive pole series connection of the DC side load of AC-DC converter.

5. a kind of peculiar to vessel high-power AC-DC converter based on thyristor according to claim 4 is characterized in that: described current transformer and voltage transformer parallel connection or be connected on AC-DC converter AC side output.

6. a kind of peculiar to vessel high-power AC-DC converter according to claim 5 based on thyristor; It is characterized in that: said sampled signal processing module is made up of voltage follower concatenation operation comparator, with the pro rata signal that satisfies the analog-to-digital conversion module standard for manual sampling that is transformed into of input signal.

7. a kind of peculiar to vessel high-power AC-DC converter according to claim 6 based on thyristor; It is characterized in that: said switching value output module connects relay by triode and forms; Input signal makes the triode conducting, is accomplished the warning and the protection of circuit by triode control relay on off state.

Images