Contactor anti-interference electricity module

Abstract

The utility model relates to the technical field of power electronics, in particular to an anti-interference electricity module of a contactor, which comprises a self-adaptive voltage calculation module, a flexible switching control module and a voltage detection module. The adaptive voltage calculation module analyzes the influence of AC / DC switching on the AC contactor under different switching phases, determines a phase interval of flexible switching, adaptively calculates the optimal DC holding voltage, and is suitable for AC contactors with various capacities. The flexible switching control module adopts alpha-beta conversion to calculate coil voltage, quickly judges the state of interference electricity, switches from alternating current to direct current when interference electricity occurs, and performs reverse switching after the interference electricity is recovered, so that stable actuation of the contactor is ensured. The voltage detection module monitors the voltage of the power grid in real time, and timely discovers and responds to an interference electricity event. Through the flexible switching after the generation and recovery of the interference electricity, the stable and reliable actuation of the AC contactor is ensured, the contact vibration and impact caused by tripping or current overshoot in the switching process are avoided, and the service life of the contactor is effectively ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of power electronics, and more specifically, to an anti-voltage-sag module for contactors. Background Art

[0002] In the power system, voltage sags (commonly known as "voltage dips") are a common problem, which may be caused by grid fluctuations, large load startups, or other external factors. Although this voltage drop is short-lived, it is sufficient to cause the contacts of the AC contactor to release, thereby affecting the normal operation of the system. To solve this problem, there are currently two main coping strategies: the voltage-sag restart scheme and the voltage-sag hold scheme.

[0003] The basic idea of the voltage-sag restart scheme is to restart the affected equipment after the voltage returns to normal. Although this scheme is simple and easy to implement, when the voltage recovers, the AC contactor will start directly, which is likely to generate closing shocks, damage the equipment, and affect its service life.

[0004] The voltage-sag hold scheme attempts to ensure that the contactor remains in the closed state during the voltage drop by using energy storage delay modules, power compensation schemes, or dual-power switching. Although this scheme can avoid unplanned shutdowns of equipment to a certain extent, due to the insufficient consideration of the influence of different phases on the AC contactor during the switching process, in actual applications, the contactor may trip or form current overshoots due to unreasonable switching phases, which may in turn cause problems such as contact vibration and shock, and this will also damage the contactor and shorten its service life. Summary of the Utility Model

[0005] The purpose of the utility model is to provide an anti-voltage-sag module for contactors to solve the problems in the above background art that the AC contactor starts directly after the voltage recovers, which is likely to cause closing shocks, and unreasonable switching phases lead to contactor tripping or current overshoots, resulting in contact vibration and shock of the contactor.

[0006] To achieve the above purpose, the utility model provides an anti-voltage-sag module for contactors, including an adaptive voltage calculation module, a flexible switching control module, and a voltage detection module. The voltage detection module is connected in parallel to the main line of the AC power supply. The AC power supply is connected to the contactor and then to the load. The contactor is connected to the adaptive voltage calculation module and the flexible switching control module. The flexible switching control module includes a voltage comparison control unit and a flexible switching circuit, where:

[0007] The flexible switching circuit includes thyristors Q1, Q2, Q3, and Q4. The anode of thyristor Q1 is connected to the AC power supply, the cathode of thyristor Q1 is connected to inductor L, the other end of inductor L is connected to resistor R, the other end of resistor R is connected to the AC power supply, the cathode of thyristor Q3 is connected to the AC power supply, and the anode of thyristor Q3 is connected to inductor L;

[0008] The anode of thyristor Q2 is connected to the positive pole of DC power supply interface 1, the cathode of thyristor Q2 is connected to inductor L, resistor R is connected to the negative pole of DC power supply interface 1, the cathode of thyristor Q4 is connected to the negative pole of DC power supply interface 1, the anode of thyristor Q4 is connected to inductor L, and resistor R is connected to the anode of DC power supply interface 2.

[0009] As a further improvement of this technical solution, the gates of thyristors Q1, Q2, Q3, and Q4 are connected to a voltage comparison control unit.

[0010] As a further improvement of this technical solution, the adaptive voltage calculation module, voltage comparison control unit, and voltage detection module are connected to the main control MCU unit.

[0011] As a further improvement of this technical solution, the DC power supply includes a DC energy storage device, an AC / DC module, and a DC / AC module. The AC / DC module is connected in parallel to the main AC power line, the AC / DC module is connected to the DC energy storage device, the DC energy storage device is connected to the DC / AC module, and the DC / AC module is connected to the flexible switching control module.

[0012] Compared with the prior art, the beneficial effects of the present utility model are as follows:

[0013] 1. In the anti-voltage-sag module of this contactor, through the coordinated operation of the voltage comparison control unit in the flexible switching control module and the flexible switching circuit composed of thyristors, combined with the signals of the voltage detection module, the voltage applied to the coil is calculated using the αβ transformation, quickly and effectively determining the occurrence and recovery status of voltage sags. When a voltage sag occurs, the control source is switched from the AC control source to the DC control source; after the voltage sag is restored, the control source is switched from the DC control source to the AC control source again, realizing the flexible switching of the AC and DC control sources. Through the optimized flexible switching control strategy, the control performance of the system is enhanced, making the operation of the contactor more stable, ensuring the stable and reliable suction of the AC contactor, avoiding the problem of contact release caused by voltage drop and the closing impact generated when the contactor directly starts during voltage recovery, improving the overall stability of the system, thereby reducing the damage to the contactor and related equipment and extending the service life of the equipment.

[0014] 2. In the anti - power - fluctuation module of the contactor, the adaptive voltage calculation module analyzes the impact on the AC contactor during AC - DC switching at different switching phases, determines the phase interval for flexible switching, and then adaptively calculates the optimal DC holding voltage to ensure that this solution can be applied to AC contactors of various capacities to match the mainstream ordinary - coil AC contactors with a capacity of 400 A and below. Brief Description of the Drawings

[0015] Figure 1 It is a schematic diagram of the overall structure of the present utility model;

[0016] Figure 2 It is a topology diagram of flexible switching of the present utility model;

[0017] Figure 3 It is a flowchart of the switching during the power - fluctuation holding stage of the present utility model. Detailed Embodiment

[0018] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the drawings in the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments. Based on the embodiments in the present utility model, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the scope of protection of the present utility model.

[0019] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality of" means two or more unless otherwise specifically defined.

[0020] Please refer to Figures 1 - 3 As shown, this embodiment provides an anti - power - fluctuation module for a contactor, which includes an adaptive voltage calculation module, a flexible switching control module, and a voltage detection module. The voltage detection module is connected in parallel to the main line of the AC power supply. The AC power supply is connected to the contactor and then to the load. The contactor is connected to the adaptive voltage calculation module and the flexible switching control module. The flexible switching control module includes a voltage comparison control unit and a flexible switching circuit. The main function of the adaptive voltage calculation module is to analyze the impact of AC - DC switching on the AC contactor at different switching phases, determine the phase interval for flexible switching, and adaptively calculate the optimal DC holding voltage to be applicable to AC contactors of various capacities. The voltage detection module is connected in parallel to the main line of the AC power supply and monitors the grid voltage in real - time. Once the voltage detection module detects that the voltage drops to the preset threshold, it immediately sends a signal to the voltage comparison control unit.

[0021] The flexible switching circuit includes thyristors Q1, Q2, Q3, and Q4. The anode of thyristor Q1 is connected to the AC power supply, the cathode of thyristor Q1 is connected to inductor L, the other end of inductor L is connected to resistor R, the other end of resistor R is connected to the AC power supply, the cathode of thyristor Q3 is connected to the AC power supply, and the anode of thyristor Q3 is connected to inductor L; the anode of thyristor Q2 is connected to the positive pole of DC power supply interface 1, the cathode of thyristor Q2 is connected to inductor L, resistor R is connected to the negative pole of DC power supply interface 1, the cathode of thyristor Q4 is connected to the negative pole of DC power supply interface 1, the anode of thyristor Q4 is connected to inductor L, and resistor R is connected to the anode of DC power supply interface 2.

[0022] Inductor L and resistor R are analog contactors, hereinafter referred to as load RL. When the grid voltage is normal, thyristors Q1 and Q2 conduct, converting the AC voltage into a pulsating DC voltage to supply the load RL. If there is a voltage dip in the grid voltage and the amplitude of the AC voltage decreases, thyristors Q3 and Q4 start to conduct, enabling the DC power supply to supply power to the load RL through resistor R, thus maintaining the suction state of the contactor. After returning to normal, thyristors Q1 and Q2 once again become the main power supply path, and the DC power supply and resistor R no longer participate in power supply.

[0023] The gates of thyristors Q1, Q2, Q3, and Q4 are connected to a voltage comparison control unit. The voltage comparison control unit calculates the voltage applied to the coil using αβ transformation, quickly and effectively determines the occurrence and recovery status of the voltage dip, and by controlling the gates of the thyristors, switches from the AC control source to the DC control source when the voltage dip occurs, and switches from the DC control source to the AC control source after the voltage dip recovers, to ensure the stable suction of the AC contactor.

[0024] The adaptive voltage calculation module, voltage comparison control unit, and voltage detection module are connected to the main control MCU unit. The main control MCU unit is responsible for receiving information from each module and coordinating the operation of the entire system.

[0025] The DC power supply includes a DC energy storage device, an AC / DC module, and a DC / AC module. The AC / DC module is connected in parallel to the main line of the AC power supply, the AC / DC module is connected to the DC energy storage device, the DC energy storage device is connected to the DC / AC module, and the DC / AC module is connected to the flexible switching control module. The AC / DC module is installed in the main line of the AC power supply, responsible for converting AC power into DC power and storing the converted DC electrical energy in the DC energy storage device. The DC energy storage device is used to store electrical energy and can quickly provide energy to maintain the suction state of the contactor coil when a voltage dip occurs. The DC / AC module is located between the DC energy storage device and the flexible switching control module, responsible for converting DC power into AC power when needed for use by the flexible switching control module. These components work together to ensure that a stable DC power supply can be provided to maintain the stable suction of the AC contactor when a voltage dip occurs.

[0026] The above has shown and described the basic principles, main features and advantages of the present utility model. Those skilled in the art should understand that the present utility model is not limited by the above embodiments. The above embodiments and the descriptions in the specification are only the preferred examples of the present utility model and are not used to limit the present utility model. Without departing from the spirit and scope of the present utility model, the present utility model will have various changes and improvements, and these changes and improvements all fall within the scope of the present utility model claimed. The scope of protection claimed by the present utility model is defined by the appended claims and their equivalents.

Claims

1. The contactor anti-sway module is characterized by: It includes an adaptive voltage calculation module, a flexible switching control module and a voltage detection module. The voltage detection module is connected in parallel to the main line of the AC power supply. The AC power supply is connected to the load through a contactor. The contactor is connected to the adaptive voltage calculation module and the flexible switching control module. The flexible switching control module includes a voltage comparison control unit and a flexible switching circuit, wherein: The flexible switching circuit comprises a thyristor Q1, a thyristor Q2, a thyristor Q3 and a thyristor Q4, wherein the anode of the thyristor Q1 is connected to an AC power supply, the cathode of the thyristor Q1 is connected to an inductor L, the other end of the inductor L is connected to a resistor R, the other end of the resistor R is connected to an AC power supply, the cathode of the thyristor Q3 is connected to the AC power supply, and the anode of the thyristor Q3 is connected to the inductor L; The anode of the thyristor Q2 is connected to the positive pole of the DC power supply interface 1, the cathode of the thyristor Q2 is connected to the inductor L, the resistor R is connected to the negative pole of the DC power supply interface 1, the cathode of the thyristor Q4 is connected to the negative pole of the DC power supply interface 1, the anode of the thyristor Q4 is connected to the inductor L, and the resistor R is connected to the anode of the DC power supply interface 2.

2. The contactor anti-electrical shaking module according to claim 1, characterized in that: The gates of the thyristor Q1 , thyristor Q2 , thyristor Q3 and thyristor Q4 are connected to a voltage comparison control unit.

3. The contactor anti-electrical shaking module according to claim 1, characterized in that: The adaptive voltage calculation module, the voltage comparison control unit and the voltage detection module are connected to the main control MCU unit.

4. The contactor anti-electrical shaking module according to claim 1, characterized in that: The DC power supply includes a DC energy storage device, an AC / DC module and a DC / AC module. The AC / DC module is connected in parallel to the AC power main line, the AC / DC module is connected to the DC energy storage device, the DC energy storage device is connected to the DC / AC module, and the DC / AC module is connected to the flexible switching control module.

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