CN108879672B - Micro-grid three-phase thyristor fast switch and control method - Google Patents
Micro-grid three-phase thyristor fast switch and control method Download PDFInfo
- Publication number
- CN108879672B CN108879672B CN201810838960.3A CN201810838960A CN108879672B CN 108879672 B CN108879672 B CN 108879672B CN 201810838960 A CN201810838960 A CN 201810838960A CN 108879672 B CN108879672 B CN 108879672B
- Authority
- CN
- China
- Prior art keywords
- thyristor
- phase
- switch circuit
- load
- energy storage
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
Abstract
The invention discloses a microgrid three-phase thyristor fast switch and a control method, the fast switch comprises a three-phase power grid, a LOAD LOAD, a three-phase thyristor bidirectional switch circuit A and a three-phase thyristor forced commutation switch circuit B, CPU, the three-phase power grid is connected with the input end of the three-phase thyristor bidirectional switch circuit A, the output end of the three-phase thyristor bidirectional switch circuit A is connected with the LOAD LOAD through the three-phase thyristor forced commutation switch circuit B, and a CPU unit is respectively connected with the control end of the three-phase thyristor bidirectional switch circuit A and the control end of the three-phase thyristor forced commutation switch circuit B. The thyristor switch has a forced turn-off function, meets the requirement of quick grid-connected and off-grid switching of a microgrid system, considers the problem of possible conduction failure of a voltage zero crossing point, not only realizes the turn-off function of the thyristor switch, but also effectively solves the problem that capacitance discharges to the microgrid due to the conduction failure.
Description
Technical Field
The invention relates to a micro-grid three-phase thyristor fast switch and a control method, and belongs to the technical field of micro-grid fast switches.
Background
Because the contradiction between the rapidly-increased power demand and the gradual exhaustion of the traditional energy and the environmental pollution is gradually highlighted, the development of new energy and renewable energy becomes a necessary choice for solving the contradiction between the shortage of global energy and environmental protection, and the development and utilization of new energy are written into the development plan of each country. Compared with the traditional large power grid, the distributed power generation has the characteristics of no pollution, flexible installation place, high energy utilization rate, reduction of power transmission loss energy of a long line and the like. But the problems of the distributed power supply are gradually revealed, and the distributed power supply is difficult to control, unstable and high in cost. With the development of power electronic technology and modern control, micro-grids have appeared, which are formed by combining micro-sources, loads, control equipment and energy storage equipment to form a controllable unit for providing electric energy or heat energy for users. Compared with a large power grid, the micro-grid is closer to the load, extra-high voltage and long-distance power grids do not need to be built for power transmission, the line loss is greatly reduced, the micro-grid has multiple functions of power generation, heat supply, refrigeration and the like, and higher comprehensive energy utilization rate can be realized; the micro-grid can run in an isolated island mode under the condition that a large grid is disturbed, power is supplied to a load, and reliability of power supply of a user is improved; the micro-grid can coordinate the distributed power supply in a mode with higher non-concentration degree, so that the burden of large grid control can be relieved, and the advantages of the distributed power supply can be better played. Compared with the independent power supply of a large power grid, the combined use of the micro power grid and the large power grid has obvious advantages.
The traditional fast switch mostly adopts a mechanical contact structure, the requirement of completing grid-connected switching within 10ms of a micro-grid is difficult to meet, a static transfer switch commonly used on a UPS also adopts a thyristor power device, but the thyristor does not have a reverse turn-off function, and the static transfer switch does not have the function requirement of forced turn-off. The fast switch on the direct current high voltage system generally adopts a GTO device with a turn-off function, has high cost and is difficult to apply to a micro-grid system, and the low voltage direct current system also has some thyristor back-pressure circuits, but has low reliability and is difficult to apply to micro-grid engineering due to the phase change problem of the alternating current system.
How to solve the technical problems is a technical problem in the field.
A UPS (Uninterruptible Power System/Uninterruptible Power Supply), that is, an Uninterruptible Power Supply, is a System device that connects a battery (mostly a lead-acid maintenance-free battery) with a host and converts direct current into commercial Power through a module circuit such as a host inverter.
Disclosure of Invention
The invention aims to solve the technical problem of providing a micro-grid three-phase thyristor fast switch, which meets the fast grid-connection and grid-disconnection requirements of a micro-grid. The common Static Transfer Switch (STS), the fast switch on the DC high-voltage system and the fast switch on the low-voltage DC system are difficult to meet the requirement of the micro-grid
The invention adopts the following technical scheme: a microgrid three-phase thyristor fast switch comprises a three-phase power grid and a LOAD LOAD, and is characterized by further comprising a three-phase thyristor bidirectional switch circuit A and a three-phase thyristor forced commutation switch circuit B, CPU unit, wherein the three-phase power grid is connected with the input end of the three-phase thyristor bidirectional switch circuit A, the output end of the three-phase thyristor bidirectional switch circuit A is connected with the LOAD LOAD through the three-phase thyristor forced commutation switch circuit B, and the CPU unit is respectively connected with the control end of the three-phase thyristor bidirectional switch circuit A and the control end of the three-phase thyristor forced commutation switch circuit B.
As a preferred embodiment, the three-phase thyristor bidirectional switch circuit a includes a first group of thyristor units, a second group of thyristor units, and a third group of thyristor units, an input end of the first group of thyristor units is connected to the phase a of the three-phase power grid, an input end of the second group of thyristor units is connected to the phase B of the three-phase power grid, an input end of the third group of thyristor units is connected to the phase c of the three-phase power grid, and an output end of the first group of thyristor units, an output end of the second group of thyristor units, and an output end of the third group of thyristor units are respectively connected to the three-phase thyristor forced commutation switch circuit B.
As a preferred embodiment, the first group of thyristor units comprises a thyristor T1, a thyristor T2, the thyristor T1 is connected in anti-parallel with the thyristor T2; the second group of thyristor cells comprises a thyristor T3, a thyristor T4, the thyristor T3 is connected in anti-parallel with the thyristor T4; the third group of thyristor units comprises a thyristor T5 and a thyristor T6, and the thyristor T5 is connected in anti-parallel with the thyristor T6.
In a preferred embodiment, the anode of the thyristor T1 is connected to the LOAD, the cathode of the thyristor T1 is connected to the phase a of the three-phase grid, the anode of the thyristor T2 is connected to the phase a of the three-phase grid, the cathode of the thyristor T2 is connected to the LOAD, and the gate of the thyristor T1 and the gate of the thyristor T2 are respectively connected to the CPU unit;
the anode of the thyristor T3 is connected with the LOAD LOAD, the cathode of the thyristor T3 is connected with the phase b of the three-phase power grid, the anode of the thyristor T4 is connected with the phase b of the three-phase power grid, the cathode of the thyristor T4 is connected with the LOAD LOAD, and the gate of the thyristor T4 and the gate of the thyristor T3 are respectively connected with the CPU unit;
the anode of the thyristor T5 is connected with the LOAD LOAD, the cathode of the thyristor T5 is connected with the c phase of the three-phase power grid, the anode of the thyristor T6 is connected with the c phase of the three-phase power grid, the cathode of the thyristor T6 is connected with the LOAD LOAD, and the gate of the thyristor T5 and the gate of the thyristor T6 are respectively connected with the CPU unit.
As a preferred embodiment, the three-phase thyristor forced commutation switch circuit B includes a forward commutation switch circuit and a reverse commutation switch circuit, the forward commutation switch circuit and the reverse commutation switch circuit are connected in parallel, an input end of the forward commutation switch circuit and an input end of the reverse commutation switch circuit are respectively connected to the three-phase power grid, and an output end of the forward commutation switch circuit and an output end of the reverse commutation switch circuit are respectively connected to the LOAD.
As a preferred embodiment, the forward-direction commutation switch loop includes a thyristor T2 ', a thyristor T4', a thyristor T6 ', a resistor R2, a resistor R4, a resistor R6, an energy storage capacitor C2, an energy storage capacitor C4, and an energy storage capacitor C6, and the reverse-direction commutation switch loop includes a thyristor T1', a thyristor T3 ', a thyristor T5', a resistor R1, a resistor R3, a resistor R5, an energy storage capacitor C1, an energy storage capacitor C3, and an energy storage capacitor C5;
the anode of the thyristor T2 'is connected to the phase a of the three-phase power grid, the cathode of the thyristor T2' is connected to one end of the resistor R2 and one end of the energy storage capacitor C2, the other end of the resistor R2 is connected to the LOAD and GND terminals, the other end of the energy storage capacitor C2 is connected to one end of the energy storage capacitor C1, the other end of the energy storage capacitor C1 is connected to the anode of the thyristor T1 'and one end of the resistor R1, the other end of the resistor R1 is connected to the LOAD and GND terminals, and the cathode of the thyristor T1' is connected to the phase a of the three-phase power grid;
the anode of the thyristor T4 'is connected to the phase b of the three-phase power grid, the cathode of the thyristor T4' is connected to one end of the resistor R4 and one end of the energy storage capacitor C4, the other end of the resistor R4 is connected to the LOAD and GND terminals, the other end of the energy storage capacitor C4 is connected to one end of the energy storage capacitor C3, the other end of the energy storage capacitor C3 is connected to the anode of the thyristor T3 'and one end of the resistor R3, the other end of the resistor R3 is connected to the LOAD and GND terminals, and the cathode of the thyristor T3' is connected to the phase b of the three-phase power grid;
the anode of the thyristor T6 'is connected to the C-phase of the three-phase power grid, the cathode of the thyristor T6' is connected to one end of the resistor R6 and one end of the energy storage capacitor C6, the other end of the resistor R6 is connected to the LOAD and GND terminals, the other end of the energy storage capacitor C6 is connected to one end of the energy storage capacitor C5, the other end of the energy storage capacitor C5 is connected to the anode of the thyristor T5 'and one end of the resistor R5, the other end of the resistor R5 is connected to the LOAD and GND terminals, and the cathode of the thyristor T5' is connected to the C-phase of the three-phase power grid;
the gate of the thyristor T2 ', the gate of the thyristor T4', the gate of the thyristor T6 ', the gate of the thyristor T1', the gate of the thyristor T3 'and the gate of the thyristor T5' are respectively connected with the CPU unit.
As a preferred embodiment, the microgrid three-phase thyristor fast switch further comprises a voltage sensor and a voltage differential sampling circuit, the voltage sensor is arranged at the input end of the three-phase thyristor bidirectional switch circuit a and connected with the CPU unit, and the voltage differential sampling circuit is respectively arranged at the input end and the output end of the three-phase thyristor bidirectional switch circuit a and connected with the CPU unit.
The invention also provides a control method of the micro-grid three-phase thyristor fast switch, which is characterized by comprising the following steps:
step SS 1: when the micro-grid three-phase thyristor fast switch operates, detecting voltages Ua, Ub and Uc of a three-phase grid through a voltage sensor, and detecting three-phase input and output voltage differences Usa, Usb and Usc of a three-phase thyristor bidirectional switch circuit A through a voltage difference sampling circuit;
step SS 2: comparing the absolute value of the three-phase input and output voltage difference with Umax to obtain a three-phase logic signal and transmitting the three-phase logic signal to a CPU unit, wherein the Umax is a thyristor on-off working condition judgment threshold value of a three-phase thyristor bidirectional switch circuit A in a three-phase thyristor fast switch of the microgrid;
step SS 3: and the CPU unit respectively sends out driving signals to the three-phase thyristor bidirectional switch circuit A and the three-phase thyristor forced commutation switch circuit B according to the three-phase logic signals in the step SS 2.
As a preferred embodiment, step SS2 specifically includes: and when the absolute values of the three-phase input and output voltage differences Usa, Usb and Usc of the three-phase thyristor bidirectional switch circuit A are smaller than Umax, the logic signals are taken as 1, otherwise, the logic signals are taken as 0, and the three-phase logic signals SA, SB and SC are obtained.
As a preferred embodiment, step SS3 specifically includes: after the CPU unit receives a turn-off instruction of a micro-grid three-phase thyristor fast switch, the CPU unit firstly judges the values of the three-phase logic signals SA, SB and SC, the logic signal in the three phases is a phase of '0', the CPU unit does not need to trigger a driving signal of a three-phase thyristor forced commutation switch circuit B of the phase, the logic signal in the three phases is a phase of '1', the CPU unit then judges the positive and negative values of the phase grid voltages Ua, Ub and Uc, if the phase voltage is greater than or equal to 0, the CPU unit triggers a driving signal of a forward commutation switch loop of the three-phase thyristor forced commutation switch circuit B of the phase, and if the phase voltage is less than or equal to 0, the CPU unit triggers a driving signal of a reverse commutation switch loop of the three-phase thyristor forced commutation switch circuit B of the phase.
The invention achieves the following beneficial effects: the thyristor rapid switch action time is less than 200 mu s, the thyristor rapid switch action time has a forced turn-off function, the requirement of rapid grid-connected and off-grid switching of a microgrid system is met, and the problem of possible conduction failure of a voltage zero crossing point is considered, and the thyristor turn-off method is designed, so that the turn-off function of the thyristor switch is realized, and the problem that capacitance discharges to the microgrid due to conduction failure is effectively solved.
Drawings
Fig. 1 is an overall circuit connection schematic diagram of a preferred embodiment of a microgrid three-phase thyristor fast switch of the present invention, wherein the labeled meanings are as follows: the system comprises a three-phase power grid, a three-phase thyristor bidirectional switch circuit A, a three-phase thyristor forced commutation switch circuit B, a LOAD LOAD (LOAD, a voltage sensor 6 and a voltage differential sampling circuit 7.
Fig. 2 is a specific circuit connection schematic diagram of a preferred embodiment of the microgrid three-phase thyristor fast switch of the invention.
Fig. 3 is a current flow diagram of the forward conduction of a microgrid three-phase thyristor fast switch.
Fig. 4 is a current flow diagram of forced commutation when the micro-grid three-phase thyristor fast switch is in forward conduction.
Fig. 5 is a discharge current flow diagram of an energy storage capacitor when the forward conduction of the three-phase thyristor fast switch of the microgrid fails.
Fig. 6 is a side current waveform diagram of the microgrid system at the moment of discharging of the energy storage capacitor when the rapid switch of the three-phase thyristor of the microgrid fails to conduct.
Fig. 7 is a microgrid system side current waveform diagram when the conduction of the microgrid three-phase thyristor fast switching control method fails.
Detailed Description
The invention is further described below with reference to the accompanying drawings. The following examples are only for illustrating the technical solutions of the present invention more clearly, and the protection scope of the present invention is not limited thereby.
Fig. 1 is a schematic diagram of an overall circuit connection of a preferred embodiment of a microgrid three-phase thyristor fast switch according to the present invention, which provides a microgrid three-phase thyristor fast switch, including a three-phase grid 1 and a LOAD4, and is characterized by further including a three-phase thyristor bidirectional switch circuit a2, a three-phase thyristor forced commutation switch circuit B3, and a CPU unit 5, where the three-phase grid 1 is connected to an input end of the three-phase thyristor bidirectional switch circuit a2, an output end of the three-phase thyristor bidirectional switch circuit a2 is connected to the LOAD4 through the three-phase thyristor forced commutation switch circuit B3, and the CPU unit 5 is connected to a control end of the three-phase thyristor bidirectional switch circuit a2 and a control end of the three-phase thyristor forced commutation switch circuit B3, respectively.
As a preferred embodiment, the microgrid three-phase thyristor fast switch further comprises a voltage sensor 6 and a voltage differential sampling circuit 7, the voltage sensor 6 is disposed at an input end of the three-phase thyristor bidirectional switch circuit a2 and connected with the CPU unit 5, and the voltage differential sampling circuit 7 is respectively disposed at an input end and an output end of the three-phase thyristor bidirectional switch circuit a2 and connected with the CPU unit 5.
Fig. 2 is a specific circuit connection schematic diagram of a preferred embodiment of the microgrid three-phase thyristor fast switch of the invention. As a preferred embodiment, the three-phase thyristor bidirectional switch circuit a realizes a rapid turn-on function of a microgrid three-phase thyristor rapid switch, and includes a first group of thyristor units, a second group of thyristor units, and a third group of thyristor units, where an input end of the first group of thyristor units is connected to phase a of the three-phase grid, an input end of the second group of thyristor units is connected to phase B of the three-phase grid, an input end of the third group of thyristor units is connected to phase c of the three-phase grid, and an output end of the first group of thyristor units, an output end of the second group of thyristor units, and an output end of the third group of thyristor units are respectively connected to the three-phase thyristor forced commutation switch circuit B; the CPU unit collects the power grid voltage of the input end of the three-phase thyristor bidirectional switch circuit A, triggers the forward thyristor to be conducted at the zero crossing point of the positive half cycle of the phase power grid voltage in sequence, and triggers the reverse voltage to be conducted at the zero crossing point of the negative half shaft of the phase power grid voltage, so that the rapid switching-on function of the rapid switch is realized.
As a preferred embodiment, the first group of thyristor units comprises a thyristor T1, a thyristor T2, the thyristor T1 is connected in anti-parallel with the thyristor T2; the second group of thyristor cells comprises a thyristor T3, a thyristor T4, the thyristor T3 is connected in anti-parallel with the thyristor T4; the third group of thyristor units comprises a thyristor T5 and a thyristor T6, and the thyristor T5 is connected in anti-parallel with the thyristor T6.
In a preferred embodiment, the anode of the thyristor T1 is connected to the LOAD, the cathode of the thyristor T1 is connected to the phase a of the three-phase grid, the anode of the thyristor T2 is connected to the phase a of the three-phase grid, the cathode of the thyristor T2 is connected to the LOAD, and the gate of the thyristor T1 and the gate of the thyristor T2 are respectively connected to the CPU unit;
the anode of the thyristor T3 is connected with the LOAD LOAD, the cathode of the thyristor T3 is connected with the phase b of the three-phase power grid, the anode of the thyristor T4 is connected with the phase b of the three-phase power grid, the cathode of the thyristor T4 is connected with the LOAD LOAD, and the gate of the thyristor T4 and the gate of the thyristor T3 are respectively connected with the CPU unit;
the anode of the thyristor T5 is connected with the LOAD LOAD, the cathode of the thyristor T5 is connected with the c phase of the three-phase power grid, the anode of the thyristor T6 is connected with the c phase of the three-phase power grid, the cathode of the thyristor T6 is connected with the LOAD LOAD, and the gate of the thyristor T5 and the gate of the thyristor T6 are respectively connected with the CPU unit.
As a preferred embodiment, the three-phase thyristor forced commutation switch circuit B implements a fast turn-off function of a microgrid three-phase thyristor fast switch, and includes a forward commutation switch loop and a reverse commutation switch loop, where the forward commutation switch loop and the reverse commutation switch loop are connected in parallel, an input end of the forward commutation switch loop and an input end of the reverse commutation switch loop are respectively connected to the three-phase power grid, and an output end of the forward commutation switch loop and an output end of the reverse commutation switch loop are respectively connected to the LOAD.
As a preferred embodiment, the forward-direction commutation switch loop includes a thyristor T2 ', a thyristor T4', a thyristor T6 ', a resistor R2, a resistor R4, a resistor R6, an energy storage capacitor C2, an energy storage capacitor C4, and an energy storage capacitor C6, and the reverse-direction commutation switch loop includes a thyristor T1', a thyristor T3 ', a thyristor T5', a resistor R1, a resistor R3, a resistor R5, an energy storage capacitor C1, an energy storage capacitor C3, and an energy storage capacitor C5;
the anode of the thyristor T2 'is connected to the phase a of the three-phase power grid, the cathode of the thyristor T2' is connected to one end of the resistor R2 and one end of the energy storage capacitor C2, the other end of the resistor R2 is connected to the LOAD and GND terminals, the other end of the energy storage capacitor C2 is connected to one end of the energy storage capacitor C1, the other end of the energy storage capacitor C1 is connected to the anode of the thyristor T1 'and one end of the resistor R1, the other end of the resistor R1 is connected to the LOAD and GND terminals, and the cathode of the thyristor T1' is connected to the phase a of the three-phase power grid;
the anode of the thyristor T4 'is connected to the phase b of the three-phase power grid, the cathode of the thyristor T4' is connected to one end of the resistor R4 and one end of the energy storage capacitor C4, the other end of the resistor R4 is connected to the LOAD and GND terminals, the other end of the energy storage capacitor C4 is connected to one end of the energy storage capacitor C3, the other end of the energy storage capacitor C3 is connected to the anode of the thyristor T3 'and one end of the resistor R3, the other end of the resistor R3 is connected to the LOAD and GND terminals, and the cathode of the thyristor T3' is connected to the phase b of the three-phase power grid;
the anode of the thyristor T6 'is connected to the C-phase of the three-phase power grid, the cathode of the thyristor T6' is connected to one end of the resistor R6 and one end of the energy storage capacitor C6, the other end of the resistor R6 is connected to the LOAD and GND terminals, the other end of the energy storage capacitor C6 is connected to one end of the energy storage capacitor C5, the other end of the energy storage capacitor C5 is connected to the anode of the thyristor T5 'and one end of the resistor R5, the other end of the resistor R5 is connected to the LOAD and GND terminals, and the cathode of the thyristor T5' is connected to the C-phase of the three-phase power grid;
the gate of the thyristor T2 ', the gate of the thyristor T4', the gate of the thyristor T6 ', the gate of the thyristor T1', the gate of the thyristor T3 'and the gate of the thyristor T5' are respectively connected with the CPU unit.
The working principle of the invention is specifically explained below by taking the thyristor T2 and the thyristor T2' as examples: when the grid voltage is in the positive half cycle, the current direction of the micro-grid three-phase thyristor fast switch is shown as an arrow in fig. 3, the grid current flows into the LOAD from the three-phase grid through the thyristor T2 of the three-phase thyristor bidirectional switch circuit a, at this time, the energy storage capacitor C2 in fig. 3 is in a charging state, and the voltage and current directions are shown in fig. 3; when the CPU unit 5 receives an off-grid command from the upper-level scheduling system, the thyristor T2' is triggered to be turned on, and at this time, the energy storage capacitor C2 generates a discharge loop, and the discharge current loop is as shown in fig. 4, and due to the low impedance characteristic of the discharge loop, the generated discharge current is large, so that the forward current of the thyristor T2 is rapidly reduced to be below the holding current, and the thyristor T2 is turned off. After the capacitor finishes discharging, because the resistance value of the resistor R is very large, the current flowing through the thyristor T2 ' can be quickly reduced to be below the latching current, at the moment, the thyristor T2 ' is turned off, and when the voltage of the power grid is in a negative half cycle, the thyristor T1 and the thyristor T1 ' are the same in the same way, and the invention is not repeated.
As a preferred embodiment, since the three-phase thyristor bidirectional switch circuit a needs to switch between positive and negative half cycles of the grid voltage, there is a conduction failure at the zero crossing point of the voltage, and a wide pulse or double narrow pulse method is mostly adopted for this problem at present to prevent the conduction failure. However, the requirement of forced turn-off exists in the field of micro-grids, a three-phase thyristor forced commutation switch circuit B is triggered when a three-phase thyristor bidirectional switch circuit a is not conducted at a voltage zero crossing point, a discharge loop of an energy storage capacitor C5 is shown in fig. 5, an energy storage capacitor C5 instantly discharges electricity to the micro-grids, a test shows that the discharge instantaneous current waveform is shown in fig. 6, and the discharge instantaneous current of an energy storage capacitor C2 is greater than 1.2kA, so that false operation of a power grid protection device can be caused.
The invention also provides a control method of the micro-grid three-phase thyristor fast switch, which is characterized by comprising the following steps:
step SS 1: when the micro-grid three-phase thyristor fast switch operates, detecting voltages Ua, Ub and Uc of a three-phase grid through a voltage sensor, and detecting three-phase input and output voltage differences Usa, Usb and Usc of a three-phase thyristor bidirectional switch circuit A through a voltage difference sampling circuit;
step SS 2: comparing the absolute value of the three-phase input and output voltage difference with Umax to obtain a three-phase logic signal and transmitting the three-phase logic signal to a CPU unit, wherein the Umax is a thyristor on-off working condition judgment threshold value of a three-phase thyristor bidirectional switch circuit A in a three-phase thyristor fast switch of the microgrid;
step SS 3: and the CPU unit respectively sends out driving signals to the three-phase thyristor bidirectional switch circuit A and the three-phase thyristor forced commutation switch circuit B according to the three-phase logic signals in the step SS 2.
As a preferred embodiment, the CPU unit detects a real-time value of the single-phase grid voltage, triggers and conducts the forward conducting thyristor T2, the thyristor T4, and the thyristor T6 when the voltage crosses a zero crossing point of a positive half cycle in a negative half cycle of the voltage, and triggers and conducts the reverse conducting thyristor T1, the thyristor T3, and the thyristor T5 when the voltage crosses a zero crossing point of a negative half cycle in the positive half cycle of the voltage, so as to ensure power supply of the microgrid system; when the CPU unit receives a superior scheduling off-grid instruction, the CPU unit judges positive and negative half cycles of single-phase power grid voltage, and triggers a thyristor T2 ', a thyristor T4 ' and a thyristor T6 ' when the power grid voltage is in the positive half cycle, reverse voltage is applied to a conducting thyristor T2, a thyristor T4 and a thyristor T6 through an energy storage capacitor C2, an energy storage capacitor C4 and an energy storage capacitor C6 respectively, and the thyristor T2, the thyristor T4 and the thyristor T6 are forced to be switched off.
As a preferred embodiment, step SS2 specifically includes: and when the absolute values of the three-phase input and output voltage differences Usa, Usb and Usc of the three-phase thyristor bidirectional switch circuit A are smaller than Umax, the logic signals are taken as 1, otherwise, the logic signals are taken as 0, and the three-phase logic signals SA, SB and SC are obtained.
As a preferred embodiment, step SS3 specifically includes: after the CPU unit receives a turn-off instruction of a micro-grid three-phase thyristor fast switch, the CPU unit firstly judges the values of the three-phase logic signals SA, SB and SC, the logic signal in the three phases is a phase of '0', the CPU unit does not need to trigger a driving signal of a three-phase thyristor forced commutation switch circuit B of the phase, the logic signal in the three phases is a phase of '1', the CPU unit then judges the positive and negative values of the phase grid voltages Ua, Ub and Uc, if the phase voltage is greater than or equal to 0, the CPU unit triggers a driving signal of a forward commutation switch loop of the three-phase thyristor forced commutation switch circuit B of the phase, and if the phase voltage is less than or equal to 0, the CPU unit triggers a driving signal of a reverse commutation switch loop of the three-phase thyristor forced commutation switch circuit B of the phase.
Fig. 7 is a turn-off instantaneous current waveform of the rapid switch for preventing conduction failure according to the present invention under a conduction failure condition, and by comparing a current waveform at the side of the microgrid system with a feedback signal of a rapid switch state and a non-impact current at the side of the microgrid system at the moment of discharging of the energy storage capacitor C2, it can be seen that no overcurrent occurs at the turn-off instant of the thyristor.
The above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, several modifications and variations can be made without departing from the technical principle of the present invention, and these modifications and variations should also be regarded as the protection scope of the present invention.
Claims (9)
1. A microgrid three-phase thyristor fast switch comprises a three-phase power grid and a LOAD LOAD, and is characterized by further comprising a three-phase thyristor bidirectional switch circuit A and a three-phase thyristor forced commutation switch circuit B, CPU unit, wherein the three-phase power grid is connected with the input end of the three-phase thyristor bidirectional switch circuit A, the output end of the three-phase thyristor bidirectional switch circuit A is connected with the LOAD LOAD through the three-phase thyristor forced commutation switch circuit B, and the CPU unit is respectively connected with the control end of the three-phase thyristor bidirectional switch circuit A and the control end of the three-phase thyristor forced commutation switch circuit B; the three-phase thyristor forced commutation switch circuit B comprises a forward commutation switch circuit and a reverse commutation switch circuit, the forward commutation switch circuit comprises a thyristor T2 ', a thyristor T4', a thyristor T6 ', a resistor R2, a resistor R4, a resistor R6, an energy storage capacitor C2, an energy storage capacitor C4 and an energy storage capacitor C6, and the reverse commutation switch circuit comprises a thyristor T1', a thyristor T3 ', a thyristor T5', a resistor R1, a resistor R3, a resistor R5, an energy storage capacitor C1, an energy storage capacitor C3 and an energy storage capacitor C5;
the anode of the thyristor T2 'is connected to the phase a of the three-phase power grid, the cathode of the thyristor T2' is connected to one end of the resistor R2 and one end of the energy storage capacitor C2, the other end of the resistor R2 is connected to the LOAD and GND terminals, the other end of the energy storage capacitor C2 is connected to one end of the energy storage capacitor C1, the other end of the energy storage capacitor C1 is connected to the anode of the thyristor T1 'and one end of the resistor R1, the other end of the resistor R1 is connected to the LOAD and GND terminals, and the cathode of the thyristor T1' is connected to the phase a of the three-phase power grid;
the anode of the thyristor T4 'is connected to the phase b of the three-phase power grid, the cathode of the thyristor T4' is connected to one end of the resistor R4 and one end of the energy storage capacitor C4, the other end of the resistor R4 is connected to the LOAD and GND terminals, the other end of the energy storage capacitor C4 is connected to one end of the energy storage capacitor C3, the other end of the energy storage capacitor C3 is connected to the anode of the thyristor T3 'and one end of the resistor R3, the other end of the resistor R3 is connected to the LOAD and GND terminals, and the cathode of the thyristor T3' is connected to the phase b of the three-phase power grid;
the anode of the thyristor T6 'is connected to the C-phase of the three-phase power grid, the cathode of the thyristor T6' is connected to one end of the resistor R6 and one end of the energy storage capacitor C6, the other end of the resistor R6 is connected to the LOAD and GND terminals, the other end of the energy storage capacitor C6 is connected to one end of the energy storage capacitor C5, the other end of the energy storage capacitor C5 is connected to the anode of the thyristor T5 'and one end of the resistor R5, the other end of the resistor R5 is connected to the LOAD and GND terminals, and the cathode of the thyristor T5' is connected to the C-phase of the three-phase power grid;
the gate of the thyristor T2 ', the gate of the thyristor T4', the gate of the thyristor T6 ', the gate of the thyristor T1', the gate of the thyristor T3 'and the gate of the thyristor T5' are respectively connected with the CPU unit.
2. The microgrid three-phase thyristor fast switch according to claim 1, characterized in that the three-phase thyristor bidirectional switch circuit a comprises a first group of thyristor units, a second group of thyristor units and a third group of thyristor units, wherein the input ends of the first group of thyristor units are connected with the phase a of the three-phase grid, the input ends of the second group of thyristor units are connected with the phase B of the three-phase grid, the input ends of the third group of thyristor units are connected with the phase c of the three-phase grid, and the output ends of the first group of thyristor units, the output ends of the second group of thyristor units and the output ends of the third group of thyristor units are respectively connected with the three-phase thyristor forced commutation switch circuit B.
3. The microgrid three-phase thyristor fast switch of claim 2, characterized in that the first group of thyristor cells comprises a thyristor T1, a thyristor T2, the thyristor T1 is connected in anti-parallel with the thyristor T2; the second group of thyristor cells comprises a thyristor T3, a thyristor T4, the thyristor T3 is connected in anti-parallel with the thyristor T4; the third group of thyristor units comprises a thyristor T5 and a thyristor T6, and the thyristor T5 is connected in anti-parallel with the thyristor T6.
4. The microgrid three-phase thyristor fast switch as claimed in claim 3, characterized in that the anode of the thyristor T1 is connected with the LOAD LOAD, the cathode of the thyristor T1 is connected with the a-phase of the three-phase power grid, the anode of the thyristor T2 is connected with the a-phase of the three-phase power grid, the cathode of the thyristor T2 is connected with the LOAD LOAD, and the gate of the thyristor T1 and the gate of the thyristor T2 are respectively connected with the CPU unit;
the anode of the thyristor T3 is connected with the LOAD LOAD, the cathode of the thyristor T3 is connected with the phase b of the three-phase power grid, the anode of the thyristor T4 is connected with the phase b of the three-phase power grid, the cathode of the thyristor T4 is connected with the LOAD LOAD, and the gate of the thyristor T4 and the gate of the thyristor T3 are respectively connected with the CPU unit;
the anode of the thyristor T5 is connected with the LOAD LOAD, the cathode of the thyristor T5 is connected with the c phase of the three-phase power grid, the anode of the thyristor T6 is connected with the c phase of the three-phase power grid, the cathode of the thyristor T6 is connected with the LOAD LOAD, and the gate of the thyristor T5 and the gate of the thyristor T6 are respectively connected with the CPU unit.
5. The microgrid three-phase thyristor fast switch according to claim 1, characterized in that the forward commutation switch loop and the reverse commutation switch loop are connected in parallel, the input end of the forward commutation switch loop and the input end of the reverse commutation switch loop are respectively connected to the three-phase power grid, and the output end of the forward commutation switch loop and the output end of the reverse commutation switch loop are respectively connected to the LOAD.
6. The microgrid three-phase thyristor fast switch according to claim 1, characterized in that the microgrid three-phase thyristor fast switch further comprises a voltage sensor and a voltage differential sampling circuit, the voltage sensor is arranged at an input end of the three-phase thyristor bidirectional switch circuit A and connected with the CPU unit, the voltage differential sampling circuit is respectively connected with an input end and an output end of the three-phase thyristor bidirectional switch circuit A, and the voltage differential sampling circuit is connected with the CPU unit.
7. The method for controlling the microgrid three-phase thyristor fast switch as claimed in claim 1, characterized by comprising the following steps:
step SS 1: when the micro-grid three-phase thyristor fast switch operates, detecting voltages Ua, Ub and Uc of a three-phase grid through a voltage sensor, and detecting three-phase input and output voltage differences Usa, Usb and Usc of a three-phase thyristor bidirectional switch circuit A through a voltage difference sampling circuit;
step SS 2: comparing the absolute value of the three-phase input and output voltage difference with Umax to obtain a three-phase logic signal and transmitting the three-phase logic signal to a CPU unit, wherein the Umax is a thyristor on-off working condition judgment threshold value of a three-phase thyristor bidirectional switch circuit A in the microgrid three-phase thyristor quick switch;
step SS 3: and the CPU unit respectively sends out driving signals to the three-phase thyristor bidirectional switch circuit A and the three-phase thyristor forced commutation switch circuit B according to the three-phase logic signals in the step SS 2.
8. The method as claimed in claim 7, wherein the step SS2 specifically includes: and when the absolute values of the three-phase input and output voltage differences Usa, Usb and Usc of the three-phase thyristor bidirectional switch circuit A are smaller than Umax, the logic signals are taken as 1, otherwise, the logic signals are taken as 0, and the three-phase logic signals SA, SB and SC are obtained.
9. The method according to claim 8, wherein the step SS3 specifically comprises: after the CPU unit receives a turn-off instruction of a micro-grid three-phase thyristor fast switch of a user, the CPU unit firstly judges the values of the three-phase logic signals SA, SB and SC, the logic signal in the three phases is a phase of '0', the CPU unit does not need to trigger a driving signal of a three-phase thyristor forced commutation switch circuit B of the phase, the logic signal in the three phases is a phase of '1', the CPU unit then judges the positive and negative values of the phase grid voltages Ua, Ub and Uc, if the phase voltage is greater than 0, the CPU unit triggers a driving signal of a forward commutation switch loop of the three-phase thyristor forced commutation switch circuit B of the phase, and if the phase voltage is less than 0, the CPU unit triggers a driving signal of a reverse commutation switch loop of the three-phase thyristor forced commutation switch circuit B of the phase.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810838960.3A CN108879672B (en) | 2018-07-27 | 2018-07-27 | Micro-grid three-phase thyristor fast switch and control method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810838960.3A CN108879672B (en) | 2018-07-27 | 2018-07-27 | Micro-grid three-phase thyristor fast switch and control method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN108879672A CN108879672A (en) | 2018-11-23 |
| CN108879672B true CN108879672B (en) | 2020-06-09 |
Family
ID=64305901
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201810838960.3A Active CN108879672B (en) | 2018-07-27 | 2018-07-27 | Micro-grid three-phase thyristor fast switch and control method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN108879672B (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109714034B (en) * | 2018-12-12 | 2023-04-21 | 崔凤来 | Automatic tracking silicon controlled rectifier quasi-current zero-crossing trigger control method and circuit |
| CN112684332B (en) * | 2020-12-14 | 2022-11-08 | 中国科学院电工研究所 | Three-phase solid-state switch test circuit and test method |
| CN112803462A (en) * | 2021-03-05 | 2021-05-14 | 上海电气集团股份有限公司 | Forced turn-off method of static transfer switch based on energy storage converter |
| CN112952846A (en) * | 2021-04-23 | 2021-06-11 | 哈尔滨易成电气有限公司 | Parallel high-speed switching type voltage sag treatment system |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5645864B2 (en) * | 2012-03-19 | 2014-12-24 | 三菱電機株式会社 | Three-phase unbalance suppression system |
| CN102790406B (en) * | 2012-08-07 | 2014-10-01 | 南京飓能电控自动化设备制造有限公司 | Doubly-fed converter with reliable low-voltage ride-through capacity |
-
2018
- 2018-07-27 CN CN201810838960.3A patent/CN108879672B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN108879672A (en) | 2018-11-23 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN108879672B (en) | Micro-grid three-phase thyristor fast switch and control method | |
| CN109167390B (en) | Photovoltaic power generation inverter system | |
| CN103296696B (en) | Inverter and control method thereof | |
| CN109787264A (en) | A kind of centralization energy-consuming device and its control method | |
| CN109494752A (en) | A kind of centralization resistance energy-consuming device and its control method | |
| WO2021197045A1 (en) | Medium-voltage photovoltaic grid-connected inverter system and photovoltaic power generation system | |
| CN110943640B (en) | Topological structure of power converter with FC bridge arm redundancy structure of T-type inverter | |
| CN111884244A (en) | Method and system for judging phase of alternating current fault on converter transformer valve side | |
| CN209787067U (en) | Brake module, brake circuit, current conversion power unit, converter valve and system | |
| CN211089218U (en) | High-capacity high-reliability rapid power supply switching device | |
| CN115102135A (en) | Thyristor-based low-loss bidirectional direct-current solid-state circuit breaker and control method thereof | |
| CN111030060A (en) | Clamp-on circuit breaker topology suitable for direct current fault removal | |
| CN114204517A (en) | Hybrid direct current breaker and control method thereof | |
| Yu et al. | A new thyristor DC solid-state circuit breaker capable of performing operating duty | |
| CN103248015B (en) | Rapid short-circuit protection system for direct current bus of energy storage converter | |
| Li et al. | Energy management strategy for renewable backup supply | |
| Eswaraiah et al. | Protection of DC bus using solid-state DC breaker | |
| EP4250513A1 (en) | Photovoltaic system, protection method, and inverter system | |
| CN207968056U (en) | A kind of ups power device using 2V accumulators | |
| CN107896102B (en) | Hybrid switch with main channel connected with solid-state switch in series | |
| CN108767882B (en) | Distributed energy storage system and control method | |
| CN210927086U (en) | Active flexible direct current power grid fault current limiter based on controllable magnetic coupling | |
| CN106921287B (en) | A kind of soft starting circuit applied in low-power Single-Phase Inverter Source | |
| CN213817249U (en) | Output device of household energy storage system | |
| CN216086148U (en) | Current-limiting type multi-port high-voltage direct-current circuit breaker and connection structure thereof in direct-current power grid |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |