CN110970910B

CN110970910B - Zero-crossing switching compound switch of unidirectional silicon controlled half-wave control capacitor and control method

Info

Publication number: CN110970910B
Application number: CN201911303550.XA
Authority: CN
Inventors: 王勇; 彭丽娜; 唐先龙
Original assignee: Chongqing Mingsike Electrical Co ltd
Current assignee: Chongqing Mingsike Electrical Co ltd
Priority date: 2019-12-17
Filing date: 2019-12-17
Publication date: 2023-04-14
Anticipated expiration: 2039-12-17
Also published as: CN110970910A

Abstract

The invention relates to a compound switch for a low-voltage distribution network, in particular to a zero-crossing switching compound switch of a unidirectional silicon controlled half-wave control capacitor and a control method thereof; specifically, an I/O output port line of the MCU processor is connected with an input end of the silicon controlled optocoupler; the output end of the silicon controlled rectifier optocoupler is connected with a gate pole signal of the unidirectional silicon controlled rectifier, the anode of the unidirectional silicon controlled rectifier is connected with the input end of three-phase power and one end of the main contact of the magnetic latching relay, and the cathode of the silicon controlled rectifier is connected with the other end of the main contact of the capacitor and the magnetic latching relay; an I/O output port line of the MCU processor is connected with an input end of a relay driving chip, and an output end of the relay driving chip is respectively connected with a coil of the magnetic latching relay; the ABC three-phase input and output end voltage conversion circuit converts the voltage of the A, B, C three-phase input and output end into a weak current signal and is connected to an ADC pin of the MCU processor; by adopting the composite switch of the technical scheme, the quantity of the silicon controlled rectifiers is small, the fatigue degree of the magnetic latching relay is controllable, and the overall reliability is high.

Description

Zero-crossing switching compound switch of unidirectional silicon controlled half-wave control capacitor and control method

Technical Field

The invention relates to a compound switch for a low-voltage distribution network, in particular to a zero-crossing switching compound switch of a unidirectional silicon controlled half-wave control capacitor and a control method thereof.

Background

The compound switch is a switch device capable of switching on, switching off, carrying and switching off current under the condition of a normal conductive loop, and is widely applied to putting and cutting off a capacitor in a reactive power compensation device in a low-voltage power distribution network such as an urban network and a rural network. The magnetic latching relay has the advantages that the advantages of the two are complementary, the characteristics of excellent static connection performance and low operation power consumption of the magnetic latching relay are brought into play, the advantage of zero-crossing switching of the silicon controlled rectifier is also effectively brought into play, and the magnetic latching relay is an ideal switching element. Therefore, the combination switch not only can inhibit the inrush current and avoid the arc discharge, but also has lower power consumption, and does not need to be additionally provided with a radiator and a cooling fan.

The controllable silicon and the magnetic latching relay are combined, the key point is that mutual time sequence matching must be tacitly defined, the controllable silicon is responsible for controlling the input and the cut-off of the capacitor, the magnetic latching relay is responsible for keeping the connection of the capacitor after the input, and the controllable silicon immediately quits the operation after the magnetic latching is input, so that a great deal of heating of the controllable silicon element can be avoided. The action of the silicon controlled rectifier and the magnetic latching relay is mainly coordinated by the central processing unit, and the specific action process is as follows: the central processing unit finds the voltage zero crossing point before the silicon controlled rectifier is put into operation, immediately sends a pulse signal to conduct the silicon controlled rectifier, then switches on the magnetic latching relay, finally cancels the silicon controlled rectifier pulse signal, switches off the silicon controlled rectifier, and only the magnetic latching relay takes the role of steady state conduction. The difficulty in the coordination process is embodied in two aspects, one is that although the thyristor is only used at the moment of switching on and switching off the capacitor, the thyristor is very sensitive to the voltage change rate and has weak capacity of bearing over-current, so that the thyristor is very easy to be switched on by mistake due to a non-zero crossing point of voltage, and a great inrush current is generated, so that the thyristor is damaged by instantaneous over-current.

And secondly, the magnetic latching relay is used as a mechanical motion part, fatigue can be generated after long-term use, so that the on-off time is changed, the on-off time is difficult to accurately realize, and the on-off time is difficult to realize after the silicon controlled rectifier is switched on, so that strong arc light can be generated, and serious consequences such as equipment burnout, main switch tripping and the like can be caused.

Disclosure of Invention

The invention aims to provide a compound switch which is small in silicon controlled rectifier quantity, controllable in fatigue degree of a magnetic latching relay and high in overall reliability.

In order to achieve the above object, the present invention provides a zero-crossing switching compound switch for a half-wave controlled unidirectional silicon capacitor, wherein the hardware part comprises: the system comprises an MCU (microprogrammed control Unit) processor, a unidirectional silicon controlled rectifier, a magnetic latching relay, an ABC three-phase input and output end voltage conversion circuit, a silicon controlled rectifier optocoupler and a relay driving chip; the controllable silicon is in forward bias, and an I/O output port line of the MCU processor is connected with an input end of the controllable silicon optocoupler; the output end of the silicon controlled rectifier optocoupler is connected with a gate pole signal of a unidirectional silicon controlled rectifier, the anode of the unidirectional silicon controlled rectifier is connected with the input end of three-phase power and one end of a main contact of the magnetic latching relay, and the cathode of the silicon controlled rectifier is connected with the other end of the main contact of the capacitor and the magnetic latching relay; an I/O output port line of the MCU processor is connected with an input end of a relay driving chip, and an output end of the relay driving chip is correspondingly connected with two ends of a coil of the magnetic latching relay; the ABC three-phase input and output end voltage conversion circuit converts the voltage of the A, B, C three-phase input and output end into a weak current signal and is connected to an ADC pin of the MCU processor;

the software part adopts the following control method: the voltage signal of three-phase input and output end that gathers through the ADC pin of MCU treater calculates the voltage of each looks input, output, judges the break-make opportunity of unidirectional silicon controlled rectifier and magnetic latching relay through the voltage value that relatively needs: when a capacitor is required to be put into the device, the MCU processor sends an input signal to the silicon controlled rectifier when detecting that the unidirectional silicon controlled rectifier is in forward bias and the voltage of the input end and the output end of the phase is equal, and simultaneously starts a timer, and sends a closing signal to the magnetic latching relay after the time is 22-t1ms, wherein t1 is the average value of the attraction time of the magnetic latching relay, and the unidirectional silicon controlled rectifier is disconnected after the magnetic latching relay is closed, so that the input of the capacitor is completed; when the capacitor needs to be cut off, the MCU processor detects that the unidirectional silicon controlled rectifier is in forward bias and the phase input end and the phase output end are equal in voltage, the timer starts timing and sends an input signal to the silicon controlled rectifier, when the time is 20-t2ms, a cut-off signal is sent to the magnetic latching relay, t2 is the average value of the breaking time of the magnetic latching relay, the unidirectional silicon controlled rectifier is cut off after the magnetic latching relay is cut off, and the capacitor is cut off.

In addition, the controllable silicon can also be in reverse bias, and at the moment, an I/O output port line of the MCU processor is connected with an input end of the controllable silicon optocoupler; the output end of the silicon controlled rectifier optocoupler is connected with a gate pole signal of a unidirectional silicon controlled rectifier, the cathode of the unidirectional silicon controlled rectifier is connected with the input end of three-phase power and one end of a main contact of the magnetic latching relay, and the anode of the silicon controlled rectifier is connected with the other end of the main contact of the capacitor and the magnetic latching relay; an I/O output port line of the MCU processor is connected with an input end of a relay driving chip, and an output end of the relay driving chip is correspondingly connected with two ends of a coil of the magnetic latching relay; the ABC three-phase input and output end voltage conversion circuit converts the voltage of the A, B, C three-phase input and output end into a weak current signal and is connected to an ADC pin of the MCU processor;

when a capacitor is required to be put in, the MCU processor sends an input signal to the controllable silicon when detecting that the unidirectional controllable silicon is in reverse bias and the phase input and output ends are equal in voltage, and simultaneously starts a timer, and sends a closing signal to the magnetic latching relay after the time is 22-t1ms, wherein t1 is the average value of the attraction time of the magnetic latching relay, and the unidirectional controllable silicon is disconnected after the magnetic latching relay is closed, so that the input of the capacitor is completed; when the capacitor needs to be cut off, the MCU processor detects that the unidirectional silicon controlled rectifier is in reverse bias and the voltage of the phase input end and the phase output end is equal, the timer starts timing and sends an input signal to the silicon controlled rectifier, when the time is 22-t2ms, a cut-off signal is sent to the magnetic latching relay, t2 is the average value of the breaking time of the magnetic latching relay, the unidirectional silicon controlled rectifier is cut off after the magnetic latching relay is cut off, and the capacitor is cut off.

The control method of the zero-crossing switching compound switch of the unidirectional silicon controlled half-wave control capacitor, which adopts the technical scheme of the invention, has the following characteristics: because the controllable silicon is very sensitive to the voltage change rate, the controllable silicon is easily conducted by mistake and damaged by inrush current impact when the voltage is suddenly changed, zero-crossing triggering is needed, a triggering signal is sent out at the moment when the voltage at two ends of the controllable silicon is zero, the controllable silicon is put into the magnetic latching relay after 2ms, the magnetic latching relay is connected with the controllable silicon in parallel for running, the magnetic latching is carried out for preset delay time according to different action delay coefficients, the delay time is matched with the time after 2ms of putting the controllable silicon into the magnetic latching relay, the unidirectional controllable silicon is switched off after the magnetic latching relay is put into the magnetic latching relay, and the controllable silicon is cut off after 20ms of putting the magnetic latching relay.

When cutting off, the current is zero; finding out the voltage peak value of a small cut-off phase, setting the pre-delay time according to the action delay coefficients of different magnetic latching relays, cutting off the contact of the magnetic latching relay of the phase when the voltage peak value is delayed, automatically detecting whether the disconnection time of the contact of the magnetic latching relay is on the voltage peak value or not in the cutting-off action process, if deviation exists, micro-automatically adjusting the contact time of the magnetic latching relay, resetting the delay time, and ensuring that the contact of the magnetic latching relay is cut off when the voltage peak value is reached.

Zero passage trigger technique can realize not having inrush current and drop into condenser, because this application technique has adopted single-phase silicon controlled rectifier, not only the silicon controlled rectifier cost reduces half, and overvoltage breakdown's possibility has also reduced half moreover, has reduced the requirement to cooling system simultaneously.

Preferably, the MCU processor records the average closing time t1 and the average breaking time t2 of the magnetic latching relay in advance, so that the action delay of the magnetic latching relay can be averaged, and the error time can be reduced.

As a preferred scheme, when the MCU detects that the disconnection time point of the main contact of the magnetic latching relay is not at the voltage peak point, the MCU processor finely adjusts the average attraction time t1 and the average disconnection time t2 of the magnetic latching relay through a software program, so that the magnetic latching relay can be accurately used through time delay correction even if the magnetic latching relay is used for a long time and action delay occurs.

Preferably, the unidirectional silicon controlled rectifier is disconnected after the magnetism is kept closed for 10-40 ms, and the capacitor is put into use.

Drawings

Fig. 1 is a frame diagram of forward bias of a circuit thyristor of a unidirectional thyristor half-wave control capacitor zero-crossing switching compound switch in an embodiment of the invention;

FIG. 2 is a block diagram of the circuit thyristor reverse bias of the unidirectional thyristor half-wave controlled capacitor zero-crossing switching compound switch in the embodiment of the invention

Fig. 3 is a flowchart of a silicon controlled rectifier forward bias switching program of the unidirectional silicon controlled rectifier half-wave control capacitor zero-crossing switching compound switch according to the embodiment of the invention.

Fig. 4 is a flowchart of a silicon controlled reverse bias switching program of the unidirectional silicon controlled half-wave control capacitor zero-crossing switching compound switch according to the embodiment of the invention.

Detailed Description

For the understanding of those skilled in the art, the present invention will be described in further detail with reference to the following drawings and detailed description, which are not intended to limit the invention:

examples

It should be noted that, unless otherwise explicitly stated or limited, the terms "mounted," "connected," "fixed," and the like are to be construed broadly and may be, for example, fixedly connected, detachably connected, or integrally connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

As shown in fig. 1 to 4: all the characteristics disclosed in the specification or all the steps in all the methods or processes disclosed can be combined in any way except mutually exclusive characteristics and/or steps. Any feature disclosed in this specification, including any accompanying claims, abstract and drawings, may be replaced by alternative features serving equivalent or similar purposes, unless expressly stated otherwise. That is, unless expressly stated otherwise, each feature is only an example of a generic series of equivalent or similar features.

As shown in fig. 1, the hardware implementation process of the core unit is as follows:

the hardware part comprises: the MCU processor selects STM32F030C8T6, a one-way silicon controlled K1, a magnetic latching relay K2, an ABC three-phase input and output end voltage conversion circuit, a silicon controlled optocoupler MOC3063 and a relay driving chip BL8023. An I/O output line of the STM32F030C8T6 processor is connected with an input end of a silicon controlled optocoupler MOC 3063; the output end of the silicon controlled optocoupler MOC3063 is connected with a gate pole signal of a unidirectional silicon controlled rectifier K1, the anode of the unidirectional silicon controlled rectifier K1 is connected with the input end of three-phase power and 3 pins at one end of a main contact of a magnetic latching relay K2, and the cathode of the silicon controlled rectifier K1 is connected with the capacitor C and 4 pins at the other end of the main contact of the magnetic latching relay K2; an I/O output port line of the STM32F030C8T6 processor is connected with an input end of a relay drive chip BL8023, and an output end of the relay drive chip BL8023 is respectively connected with a coil 1,2 pin of a magnetic latching relay K2; the ABC three-phase input and output end voltage conversion circuit converts the voltage of the A, B, C three-phase input and output end into a weak current signal and is connected to an ADC pin of an STM32F030C8T6 processor.

As in fig. 2, the software implemented algorithm is as follows:

the software part adopts the following control method: the voltage signals of the three-phase input end and the three-phase output end collected by ADC pins PA 1-PA 6 of the STM32F030C8T6 processor are used for calculating the voltage of the input end and the output end of each phase, and the on-off time of the one-way silicon controlled rectifier K1 and the magnetic latching relay K2 is judged by comparing the required voltage values.

When a capacitor is needed to be put in, the STM32F030C8T6 processor detects that the unidirectional silicon controlled rectifier K1 is in forward bias and the phase input and output ends are equal in voltage, sends an input signal to the silicon controlled rectifier, simultaneously starts a timer, sends a closing signal to the magnetic latching relay K2 after the time is 22-T1ms, T1 is the average value of the attraction time of the magnetic latching relay K2, and disconnects the unidirectional silicon controlled rectifier K1 20ms after the magnetic latching is closed, so that the capacitor is put in;

when the capacitor needs to be cut off, the STM32F030C8T6 processor finds the wave crest value of the phase needing to be cut off, the timer starts to time, when the time is 20-T2ms, a breaking signal is sent to the magnetic latching relay K2, and T2 is the average value of the breaking time of the magnetic latching relay K2, so that the capacitor is cut off.

The STM32F030C8T6 processor records the average pull-in time T1 and the average breaking time T2 of the magnetic latching relay K2 in advance, when the processor detects that the breaking time point of the main contact of the magnetic latching relay K2 is not at a voltage peak point, the STM32F030C8T6 processor automatically and finely adjusts the average pull-in time T1 and the average breaking time T2 of the magnetic latching relay, even if the magnetic latching relay is used for a long time and action delay occurs, still, the magnetic latching relay can be corrected through time delay, and accurate use is achieved.

The controllable silicon K1 can also be in reverse bias, at the moment, only a little improvement needs to be made on the control method, namely when a capacitor is needed to be put into, the STM32F030C8T6 processor detects that the one-way controllable silicon K1 is in reverse bias and the phase input and output ends are equal in voltage, sends an input signal to the controllable silicon, simultaneously starts a timer, sends a closing signal to the magnetic latching relay K2 after the time is 22-T1ms, T1 is the average value of the attraction time of the magnetic latching relay K2, and 20ms after the magnetic latching is closed, the one-way controllable silicon K1 is disconnected, so that the capacitor is put into.

Hidden troubles caused by blind closing of the magnetic latching relay when the silicon controlled rectifier is not reliably conducted are effectively avoided. The effective combination of software and hardware, input section and output section reliably cooperate, have solved the too big problem of silicon controlled rectifier surge when voltage zero-crossing detection is inaccurate, have also solved the risk of burning out equipment that magnetic latching relay closure caused when the silicon controlled rectifier is unreliable to switch on simultaneously. The core problems of safety and reliability in the design of the low-voltage compound switch are fundamentally solved, and a solid foundation is laid for the safe and reliable operation of a power system.

The invention is not limited to the foregoing embodiments. The invention extends to any novel feature or any novel combination of features disclosed in this specification, and to any novel method or process steps or any novel combination of steps disclosed. In the present invention, unless expressly stated or limited otherwise, the first feature "on" or "under" the second feature may comprise the first and second features being in direct contact, or the first and second features may be in contact by means other than the direct contact, but also by means of another feature between them. Also, the first feature "on," "above" and "over" the second feature may include the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature. The terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are only for convenience in describing and simplifying the description, and do not indicate or imply that the referred devices or elements must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention.

It should be noted that the above-mentioned embodiments are preferred implementations of the present invention, and besides, the present invention may be implemented in other ways, and any obvious substitutions, modifications and variations are within the protection scope of the present invention without departing from the spirit of the present invention.

In addition, some drawings and common sense descriptions of the present invention have been simplified in order to enable those skilled in the art to more conveniently understand the improvement of the present invention over the prior art, and some other elements have been omitted from this document for clarity, and those skilled in the art should recognize that the omitted elements also constitute the content of the present invention.

Claims

1. A control method of a unidirectional silicon controlled half-wave control capacitor zero-crossing switching compound switch is characterized by comprising the following steps: the hardware part comprises: the system comprises an MCU (microprogrammed control Unit) processor, a unidirectional silicon controlled rectifier, a magnetic latching relay, an ABC three-phase input and output end voltage conversion circuit, a silicon controlled rectifier optocoupler and a relay driving chip; the controllable silicon is in forward bias, and an I/O output line of the MCU processor is connected with an input end of the controllable silicon optocoupler; the output end of the silicon controlled rectifier optocoupler is connected with a gate pole signal of a unidirectional silicon controlled rectifier, the anode of the unidirectional silicon controlled rectifier is connected with the input end of three-phase power and one end of a main contact of the magnetic latching relay, and the cathode of the silicon controlled rectifier is connected with the other end of the main contact of the capacitor and the magnetic latching relay; an I/O output port line of the MCU processor is connected with an input end of a relay driving chip, and an output end of the relay driving chip is correspondingly connected with two ends of a coil of the magnetic latching relay; the ABC three-phase input and output end voltage conversion circuit converts the voltage of the A, B, C three-phase input and output end into a weak current signal and is connected to an ADC pin of the MCU processor;

the software part adopts the following control method: the voltage signal of the three-phase input and output end that the ADC pin through the MCU treater was gathered calculates the voltage of each phase input end, output, judges the break-make opportunity of one-way silicon controlled rectifier and magnetic latching relay through the voltage value that compares required: when a capacitor is required to be put in, the MCU processor sends an input signal to the controllable silicon when detecting that the unidirectional controllable silicon is in forward bias and the voltage of the input end and the output end of the phase is equal, and simultaneously starts a timer, and sends a closing signal to the magnetic latching relay after the time is 22-t1ms, wherein t1 is the average attraction time of the magnetic latching relay, and the unidirectional controllable silicon is disconnected after the magnetic latching relay is closed, so that the input of the capacitor is completed; when the capacitor is required to be cut off, the MCU processor detects that the unidirectional silicon controlled rectifier is in forward bias and the phase input end and the phase output end are equal in voltage, the timer starts timing and sends an input signal to the silicon controlled rectifier, when the time is 20-t2ms, a cut-off signal is sent to the magnetic latching relay, t2 is the average breaking time of the magnetic latching relay, the unidirectional silicon controlled rectifier is cut off after the magnetic latching relay is cut off, and the capacitor is cut off.

2. The control method of the unidirectional silicon controlled half-wave control capacitor zero-crossing switching compound switch according to claim 1, characterized in that: and the MCU processor records the average closing time t1 and the average breaking time t2 of the magnetic latching relay in advance.

3. The control method of the unidirectional thyristor half-wave controlled capacitor zero-crossing switching compound switch according to claim 1, characterized in that: and when the MCU processor detects that the disconnection time point of the main contact of the magnetic latching relay is not at the voltage peak point, the MCU processor finely adjusts the average attraction time t1 and the average disconnection time t2 of the magnetic latching relay through a program.

4. The control method of the unidirectional silicon controlled half-wave control capacitor zero-crossing switching compound switch according to claim 1, characterized in that: and after the magnetic field is kept closed for 10-40 ms, the unidirectional silicon controlled rectifier is disconnected, and the capacitor is put into use.

5. The control method of the unidirectional thyristor half-wave controlled capacitor zero-crossing switching compound switch according to claim 1, characterized in that: and (5) after the magnetic field is kept closed for 20-40 ms, the unidirectional silicon controlled rectifier is disconnected, and the capacitor is put into use.

6. The control method of the unidirectional silicon controlled half-wave control capacitor zero-crossing switching compound switch according to claim 1, characterized in that: the controllable silicon is in reverse bias, and an I/O output port line of the MCU processor is connected with an input end of the controllable silicon optocoupler; the output end of the silicon controlled rectifier optocoupler is connected with a gate pole signal of a unidirectional silicon controlled rectifier, the cathode of the unidirectional silicon controlled rectifier is connected with the input end of three-phase power and one end of a main contact of the magnetic latching relay, and the anode of the silicon controlled rectifier is connected with the other end of the main contact of the capacitor and the magnetic latching relay; an I/O output port line of the MCU processor is connected with an input end of a relay driving chip, and an output end of the relay driving chip is correspondingly connected with two ends of a coil of the magnetic latching relay; the ABC three-phase input and output end voltage conversion circuit converts the voltage of the A, B, C three-phase input and output end into a weak current signal and is connected to an ADC pin of the MCU processor;