CN111354587A - Accurately Controlled Drivers for Synchronized Switching - Google Patents

Abstract

The invention provides an accurate control driver for a synchronous switch (K), wherein the input of the synchronous switch (K) is the voltage of a power grid, the output of the synchronous switch is a capacitor bank (C) or a transformer (T) or a reactor (L), the synchronous switch (K) of the capacitor bank (C) is in a pre-charging type, the accurate control driver applies a simple 220V AC/DC module (6) power supply, breaks through the traditional mode of adopting a direct-current stabilized power supply, adopts an AC voltage fluctuation monitoring module (4) and a voltage fluctuation adjusting module (5) to correct the influence of positive voltage fluctuation, and applies a switch to close and open a feedback signal module (3) and a current transformer (2) to obtain a zero-crossing synchronous point and an automatic correction switching point of the synchronous switch so as to achieve the action requirement of accurately controlling and driving the high-precision synchronous switch (K) Low voltage and 8421 code large current switching are more beneficial to the application of engineering standardized products.

Description

Accurately Controlled Drivers for Synchronized Switching

technical field

The invention relates to the fields of reactive power compensation, harmonic filtering and power grid power quality control of power systems, in particular to an accurate control driver for synchronous switches.

Background technique

The power grid needs reactive power compensation to achieve the purpose of stabilizing the grid voltage, improving the power factor and reducing the line loss. In the field of reactive power compensation, about 80% use mechanical contact switches to switch capacitors. The mechanical contact switches switch capacitors at random and uncertain grid voltage phase angles, and the current during switching exceeds 4 times the normal rated current to 10, 20 times, causing grid voltage distortion. In addition, there is also a dangerous probability of the closing mechanical contact bouncing and opening the contact re-ignition. The bouncing and re-ignition make the capacitor bank overvoltage, damage the capacitor, and easily cause an accident. The reason why there is still a large market share in switching capacitors with mechanical contact switches is that the circuit is simple and the cost is low.

Later, it was found that closing the switch at the zero-crossing point of the grid voltage and opening the switch at the zero-crossing point of the current to switch the capacitor will significantly reduce the inrush current, which is the so-called synchronous switching technology. The grid voltage is a sine wave, and the zero-crossing point of the sine-wave voltage has the largest change. The zero-crossing point is required to be switched accurately, and the accuracy is +, -1ms. Because the switch is mechanical, the time of each switching has a small change, long-term work requirements It's not easy to cross zero.

There is an invention patent for the capture of the zero-crossing point of the thyristor switching voltage: "Zero-crossing trigger sequence control circuit for 2-control 3-thyristor switching capacitors", patent number: 2008101064005, to capture the two zero-crossing points of the thyristor switching sine wave action, after no action Since the thyristor operates accurately, there is no need to worry about the inaccurate switching problem, so the problem after the verification work is not considered. Patent: Synchronous switch for capacitors, patent number: 201410240278, it is mentioned that the switch is closed at the moment when the voltage at both ends of the switch contacts is zero, so as to realize the no inrush current input of the capacitor, no circuit is implemented, and there is no correction of the switching effect.

Since the sine wave voltage is changing at every moment, the 220V grid voltage is allowed to fluctuate by +7%, -10%, and it is difficult to drive directly with the grid voltage. Generally, high-precision synchronous switches are powered by DC regulated power supply, 10KV The driving voltage of the electromagnetic contactor is 220V, the current is 5A, and a large regulated power supply is required.

Now there are special capacitor contactors on the market, and the switching effect is not obvious by the method of resistance current limiting.

Now a large number of 380V grid smart capacitors appearing on the market use 220V relays, not contactors, switching current of 22A, parallel operation with small flow, and cannot achieve high current switching of 8421 yards.

After 15 years of research and development, Beijing Xinrong Zongheng Technology Development Co., Ltd. first proposed the concept of precharge switching capacitors, and then has 10 patents for precharge switches to form a patent group for precharge synchronous switch switching capacitors, such as: invention patents "Intelligent reactive power compensation device based on a single three-pole synchronous switch", patent number: 201210004876.4, invention patent "device based on synchronous precharge switch switching capacitor bank" Patent number: 201210468939.1, etc., the advantages of precharge synchronous switch It is switched at the peak point of the grid voltage. Since the rate of change of the peak voltage is zero, it is an ideal switching state, and the impact is small. Generally, the synchronous switch is at the zero point of the voltage, and the rate of change is the largest. The precharge synchronous switch is easier to meet high-precision synchronization. switch requirements. The most notable sign of the structure of the precharge synchronous switch is to connect a current limiting resistor and a precharge diode in parallel at both ends of the synchronous switch. technology of the patent group.

The development of technology never ends. In the past, Beijing Xinrong Zongheng Technology Development Co., Ltd.'s patent group technology of pre-charge synchronous switch switching capacitors mainly focused on various main circuits of pre-charge synchronous switches. How to create simple control and drive, accurate and convenient action Numerous engineering applications are the object of the present invention.

SUMMARY OF THE INVENTION

The present invention proposes an accurate control driver for a synchronous switch (K). The input of the synchronous switch (K) is the grid voltage, and the output is a capacitor bank (C) or a transformer (T) or a reactor (L). The capacitor bank The synchronous switch (K) of (C) can be a general synchronous switch or a pre-charged type, which can accurately control the driver to apply a simple 220V AC/DC module (6) power supply, breaking through the traditional mode of using a DC regulated power supply. The AC voltage fluctuation monitoring module (4) and the voltage fluctuation adjustment module (5) are used to correct the influence of the voltage fluctuation, and the switch is closed to open the feedback signal module (3) and the current transformer (2) to obtain the zero-crossing synchronization point and sum of the synchronous switch. Automatically correct the switching point to meet the action requirements of accurately controlling and driving the high-precision synchronous switch (K).

The purpose of the present invention is to make up for the deficiency of the control drive of the precharge synchronous switch, and to apply the control drive group to various loads of capacitors, reactors, and transformers, and one control drive can be applied to each of low-voltage, medium-voltage, and high-voltage. The current level is simple, economical and applicable, and the action is accurate, which is convenient for a large number of engineering applications.

Description of drawings

Fig. 1: The control driver diagram of the present invention;

Fig. 2: The switch closes and opens the feedback signal module diagram of the present invention;

Figure 3: Software program diagram of the present invention

Detailed ways

As shown in Figure 1, a control driver of the present invention controls a synchronous switch (K), the input of the synchronous switch (K) is the three-phase voltage U V W of the grid, and its output is a capacitor bank (C) or a transformer (T) or a reactance The controller (L), the control driver is composed of a controller module (9) and an accurate drive module (7). The input of the controller module (9) is the controller command (S), the debugging switch (S2), and the voltage synchronization module (1). ) and the current transformer module (2), the switch is closed to open the feedback signal module (3), the AC voltage fluctuation monitoring module (4) and the voltage fluctuation adjustment module (5), the controller module (9) obtains the information from the input terminal and executes the The software program is output to the accurate drive module (7), the power supply of the accurate drive module (7) is provided by the 220V AC/DC module (6), and the accurate drive module (7) drives the synchronous switch (K) coil, so that the synchronous switch ( The contact of K) is closed at the zero-crossing point, and is opened when the corresponding current is zero at a certain moment of the grid voltage, and the module (8) completes the bidirectional input and output information transmission of the controller module (9).

The synchronous switch (K) can be used in various occasions of high voltage and low voltage, and can use 8421 code high current switching. The synchronous switch (K) used for the capacitor bank (C) can be used alone, or the synchronous switch (K) can be connected in parallel with it. The resistor (R1) and diode (D1) are used to form the pre-charge switch, and the synchronous switch (K) can be used for the transformer (T) load and the reactor (L) load. Synchronous switch (K) is one of permanent magnet contactor, permanent magnet circuit breaker, electromagnetic contactor and electromagnetic circuit breaker.

As shown in Figure 2, the switch closed and open feedback signal module (3) provides the first-level accurate switching protection function. The input of the switch closed open feedback signal module (3) is connected to both ends of the synchronous switch (K), and the switch is closed to open the feedback Signal module (3) contains optocoupler (U1) and optocoupler (U2), optocoupler (U1) (U2) current limiting resistor (R2) and current limiting resistor (R3), synchronous switch (K) should be a pre-charge synchronous switch , it is necessary to connect the precharge circuit diode (D1) and resistor (R1) at both ends of the synchronous switch (K), the resistor (R2) is connected between the diode (D1) and the resistor (R1), the input of the optocoupler (U 1) Forward and diode (D 1) reverse connection, the input of optocoupler (U 2) forward and diode (D1) forward connection, optocoupler (U 2) input has diode (D 2) reverse protection, optocoupler (U 1) and optocoupler (U2) measure the forward and reverse voltage waveforms of the synchronous switch (K) respectively, the optocoupler (U 1) measures the zero-crossing point of the synchronous switch (K) about to act, and the optocoupler (U 2) corrects After the zero-crossing point of the synchronous switch (K), the output of the optocoupler (U 1) and the opto-coupler (U2) is sent to the controller module (1), and the synchronous switch (K) does not have the pre-charging function if the diode (D 1) is removed. .

The current transformer module (2) provides the second-level accurate switching protection, and detects the closing time of the synchronous switch (K) and opens the synchronous switch (K) when the corresponding current is zero at a certain moment of the grid voltage.

The hardware for the accurate control driver of the synchronous switch (K), the input of the controller module (9) has a voltage fluctuation monitoring module (4), the measured value of the voltage fluctuation monitoring module (4) is transferred to the voltage fluctuation adjustment module (5) ), the voltage fluctuation adjustment module (5) is input to the controller module (9), the debugging switch (S) and the grid voltage UVW are input to the controller module (9) through the voltage synchronization module (1) and the current transformer module (2) , the synchronous switch (K) is closed to open the feedback signal module (3), and the zero-crossing point of the synchronous switch (K) about to act, and the zero-crossing point after the synchronous switch (K) act, are transmitted to the controller module (9), according to the control The input hardware of the controller module (9) is executed, the program of the controller module (9) is executed, and the output signal is sent to the accurate driving module (7). (7) The synchronous K coil is driven to complete the action of the synchronous switch (K), and the communication module (8) and the controller module (9) communicate in two directions.

As shown in Figure 3, the software program of the controller module (9), the controller module (9) receives the controller command (S) to open the command, the software transfers to the command to open the program, the debug switch (S2) is closed, and the AC voltage change is measured Turn on the time, the debugging switch (S2) is turned on, the voltage phase sequence of the voltage synchronization module (1) is measured, and the current transformer module (2) detects the closing time of the synchronization switch (K) and the time when the corresponding current is zero at a certain moment of the grid voltage Turn on the sync switch (K). Measure the opening time of the synchronous switch (K), correct the input time, and adjust the switching point in the controller module (9) to achieve accurate switching. The controller gets the closing command of the command (S), the software transfers to the command to open the program, the debugging switch (S2) is closed, the closing time of the AC voltage change is measured, the debugging switch (S2) is turned on, and the switching time is modified according to the change of the voltage to achieve The zero-crossing action of closing is performed, the closing time is measured after closing, the controller module (9) receives the controller command (S) to open, executes the opening procedure, and completes the one-time procedure of opening and closing.

Beneficial technical effects of the present invention:

The invention proposes a synchronous switch accurate control driver, which can meet the switching of capacitors, reactors and transformers of high, low voltage and 8421 yard high current, and is more conducive to the application of engineering standardization products.

The specific embodiment of the present invention has made a detailed description of the content of the present invention, and those skilled in the art can make various modifications, equivalent replacements, or improvements under the inspiration of the spirit and principle of the present application. However, these variations or modifications are all within the scope of protection for which the application is pending.

Claims (6)

1. An accurate control driver for a synchronous switch, characterized by: the control driver controls a synchronous switch (K), the input of the synchronous switch (K) is power grid three-phase voltage UVW, the output of the synchronous switch is a capacitor bank (C) or a transformer (T) or a reactor (L), the control driver consists of a controller module (9) and an accurate driving module (7), the input of the controller module (9) is a controller command (S), a debugging switch (S2), a voltage synchronization module (1) and a current transformer module (2), a switch closing and opening feedback signal module (3), an AC voltage fluctuation monitoring module (4) and a voltage fluctuation adjusting module (5), the controller module (9) obtains information from the input end, executes a software program and outputs the information to the accurate driving module (7), the power supply of the accurate driving module (7) is provided by a 220V AC/DC module (6), the accurate driving module (7) drives a synchronous switch (K) coil, the contact of the synchronous switch (K) is closed at the zero crossing point, and is opened when the corresponding current is zero at a certain moment of the power grid voltage, and the communication module (8) completes the information transmission of the bidirectional input and output of the controller module (9).

2. Accurate control driver for synchronous switches according to claim 1, characterized in that: the synchronous switch (K) can be switched on in various occasions of high voltage and low voltage by adopting 8421 code large current, the synchronous switch (K) used for the capacitor bank (C) can be used independently, the synchronous switch (K) and a resistor (R1) and a diode (D1) which are connected with the synchronous switch in parallel can form a pre-charging switch for use, and the synchronous switch (K) can be used for a transformer (T) load and a reactor (L) load. The synchronous switch (K) is one of a permanent magnet contactor, a water magnetic circuit breaker, an electromagnetic contactor and an electromagnetic circuit breaker.

3. Accurate control driver for synchronous switches according to claim 1, characterized in that: the switch closing and opening feedback signal module (3) provides a first-stage accurate switching protection function, the input of the switch closing and opening feedback signal module (3) is connected to two ends of a synchronous switch (K), the switch closing and opening feedback signal module (3) comprises an optical coupler (U1) and an optical coupler (U2), the optical coupler (U1) (U2) is connected with a current limiting resistor (R2) and a current limiting resistor (R3), the synchronous switch (K) is required to be a pre-charging synchronous switch, a pre-charging circuit diode (D1) and a resistor (R1) are required to be connected to two ends of the synchronous switch (K), a resistor (R2) is connected between a diode (D1) and a resistor (R1), the input forward direction of the optical coupler (U1) is connected with the diode (D1) in a reverse direction, the input forward direction of the optical coupler (U2) is connected with a diode (D1) in a forward direction, the optical coupler (U2) is input with a diode (D2) for reverse protection, and the optical coupler (U1) and the optical coupler (U2) are, the optical coupler (U1) measures the zero crossing point of the action of the synchronous switch (K), the optical coupler (U2) corrects the zero crossing point of the action of the synchronous switch (K), the output of the optical coupler (U1) and the optical coupler (U2) is transmitted to the controller module (1), and the synchronous switch (K) without the diode (D1) has no pre-charging function.

4. Accurate control driver for synchronous switches according to claim 1, characterized in that: the current transformer module (2) provides accurate switching protection of the second stage, detects the closing time of the synchronous switch (K) and opens the synchronous switch (K) when the corresponding current is zero at a certain time of the grid voltage.

5. Accurate control driver for synchronous switches according to claim 1, characterized in that: hardware for accurately controlling a driver of a synchronous switch (K), wherein a voltage change monitoring module (4) is input into a controller module (9), a measured value of the voltage change monitoring module (4) is converted into a voltage fluctuation adjusting module (5), the voltage fluctuation adjusting module (5) is input into the controller module (9), a debugging switch (S) and a power grid voltage UVW are input into the controller module (9) through a voltage synchronizing module (1) and a current transformer module (2), the synchronous switch (K) is closed to open a feedback signal module (3) to transmit a zero crossing point of an action to be performed by the synchronous switch (K) and a zero crossing point after the action of the synchronous switch (K) to the controller module (9), a program of the controller module (9) is executed according to the input hardware of the controller module (9), a signal is output to an accurate driving module (7), and a power supply of the accurate driving module (7) is provided by a 220V AC/DC module (6), the accurate driving module (7) drives the synchronous K coil to complete the action of the synchronous switch (K), and the communication module (8) is in two-way communication with the controller module (9).

6. Accurate control driver for synchronous switches according to claim 1, characterized in that: the method comprises the steps that a software program of a controller module (9) is stored, the controller module (9) receives a controller command (S) opening command, the software is transferred to the command opening program, a debugging switch (S2) is closed, the AC voltage change opening time is measured, a debugging switch (S2) is opened, the voltage phase sequence of a voltage synchronization module (2) is measured, the voltage synchronization module is opened when the corresponding current is zero at a certain moment of the grid voltage, the opening time of a synchronization switch (K) is measured, the switching moment is corrected, and the switching point is adjusted in the controller module (9) to achieve accurate switching. The controller obtains a closing command of the command (S), software is transferred to a command opening program, a debugging switch (S2) is closed, AC voltage change closing time is measured, the debugging switch (S2) is opened, switching time is modified according to voltage change, closing zero-crossing action is achieved, closing time is measured after closing, and the controller module (9) receives the controller command (S) to open, executes the opening program and completes one program of opening and closing.

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