Electromagnetic vacuum circuit breaker synchronous operating mechanism with pressure auxiliary regulation and control

Abstract

According to the electromagnetic vacuum circuit breaker synchronous operating mechanism with the pressure auxiliary regulation and control function, pressure conduction structures, a lever structure in the vertical direction and a magnetic suspension technology are additionally arranged on the two sides of a motion structure of a circuit breaker, and circuit breaker contacts can be tightly attracted under driving of a permanent magnet rotor; two groups of parallel electromagnetic windings are adopted for axial and pitching two-degree-of-freedom switching-on control, an orthogonal pressure sensor structure arranged at the upper end of a pressure conduction rod is utilized, a small gap caused by untight attachment of a circuit breaker contact is eliminated, generation of a discharge arc during normal work is avoided, a lever mechanism in the vertical direction is introduced, and the operation stability of the circuit breaker is improved. Equipment power consumption can be reduced. By means of the real practicability, the safe and stable working state of the circuit breaker can be effectively guaranteed, and the problems of asynchronous closing and contact bounce easily existing in a traditional circuit breaker system are solved.

Description

Technical Field

[0001] The present invention relates to an electromagnetic vacuum circuit breaker mechanism, in particular to an electromagnetic operating mechanism with two-degree-of-freedom position control including pressure-assisted control, belonging to the technical field of electromagnetic circuit breakers. Background Art

[0002] Circuit breakers are widely used in power generation, distribution, and consumption, protecting equipment from line faults and overloads. With the widespread adoption and development of new energy generation technologies and electric vehicles, the use of circuit breakers in these areas is increasing.

[0003] Currently, most circuit breakers on the market use mechanical operating mechanisms. Before closing, they rely on a handle or motor to pull a spring to store energy. When closing is required, the spring is released, driving a flywheel to drive the integrated connecting rod to complete the closing process. Mechanical operating mechanisms are complex, and manual energy storage during the initial stage is detrimental to the automated control of industrial systems. Relying on motors for energy storage consumes a lot of energy and is uneconomical. Therefore, electromagnetically driven circuit breakers have been proposed. As is well known, the core component of an electromagnetic vacuum circuit breaker system is the electromagnetic coil, which generates an electromagnetic force by generating a magnetic field to actuate the operating mechanism. The reliability of the electromagnetic mechanism determines the circuit breaker's operational state in actual circuits. Currently, there are two main structures for mainstream electromagnetic circuit breakers: one with independent three-phase drive mechanisms, using three drive units to independently control the moving contacts of each phase. This not only increases the difficulty of controlling the device, but also makes it difficult to ensure synchronous closing of the three phases. If the three phases close asynchronously, current asymmetry in the circuit can occur, compromising the safe and stable operation of electrical equipment. Another structure combines the three drive mechanisms into one, using a single electromagnetic winding to drive and control the three-phase integrated connecting rod. However, due to the "mountain" shape of the three-phase integrated connecting rod, using a single electromagnetic winding for closing control can easily result in uneven force on both sides, causing the connecting rod to tilt. Once the connecting rod tilts, it will also cause inconsistent contact closing times among the three phases, resulting in asymmetric three-phase currents. In addition, current circuit breaker systems only use air gap sensors to detect the real-time position of the moving contact as a criterion for closing. However, this often leads to a problem: assuming the spacing between the moving and static contacts is δ, when the moving contact moves and the air gap sensor detects δ mm, the main control unit will send a control signal to the drive circuit to switch from the rising motion working state to the maintained closed working state. However, because the main control unit system uses the air gap value detected by the air gap sensor as a criterion to control the current in the winding, the moving and static contacts only achieve slight contact at this time, and the fit is not tight, that is, there is a small gap between them. However, because circuit breakers operate in high-voltage, high-current environments, the presence of small gaps between the contacts can lead to poor contact, resulting in arc discharges and, consequently, welding of the circuit breaker contacts, affecting the safe, stable operation and service life of the equipment. To improve the reliability of circuit breaker operation, it is necessary to develop a vacuum circuit breaker platform with a simple structure, reliable operation, and energy-saving operation. Summary of the Invention

[0004] The main purpose of the present invention is to solve the problems of asynchronous closing and loose closing of the three-phase contacts caused by existing electromagnetic circuit breaker operating mechanisms. To solve the above technical problems, an electromagnetic operating mechanism with two-degree-of-freedom control for circuit breaker with pressure-assisted control is proposed. The mechanism includes a pressure transmission rod, a pressure sensor, a position sensor, a permanent magnet actuator, an integrated connecting rod, an electromagnetic winding, a main control unit, and a converter unit. The mechanism is used to achieve tight closing of the circuit breaker contacts, ensure the horizontal upward movement of the integrated connecting rod, ensure the synchronous closing of the three-phase contacts, and achieve the compensation of three-phase asymmetry.

[0005] The pressure transmission rod adopts a right-angle structure and is located on both sides of the permanent magnet mover and is fixedly connected to the permanent magnet mover. The gap between the pressure transmission rod and the fixed crossbeam is consistent with the gap between the moving and static contacts in the vacuum interrupter, which is δ. The upper end surface of the pressure transmission rod is a disc-shaped structure, and four orthogonally distributed pressure sensors are set on each side.

[0006] The pressure sensor is used to measure the pressure between the pressure transmission rod and the fixed beam after the permanent magnet mover drives the pressure transmission rod to rise;

[0007] The permanent magnet mover is integrally connected to the central integral connecting rod and the left and right side pressure transmission rods, and is placed under the electromagnetic winding, and drives the connecting rod assembly and the contact assembly in a coordinated manner to open and close the contact assembly;

[0008] Three moving rod through-holes are provided on the fixed crossbeam, through which the integrated connecting rod is fixedly connected to the contact assembly in the vacuum interrupter. The integrated connecting rod includes a vertical moving rod and a horizontal connecting rod. After the vertical moving rod passes through the moving rod through-holes, the three connecting rods are connected as one through the horizontal connecting rod to achieve integrated movement.

[0009] The electromagnetic windings are fixed to the fixed crossbeam and the bottom of the circuit breaker respectively. Each electromagnetic winding contains 16 moving windings arranged in an N / S pattern. The electromagnetic windings are DC excitation windings connected to the motion converter. The electromagnetic windings are controlled by the motion converter and can generate both suspension attraction and suspension repulsion to control the movement of the permanent magnet as needed.

[0010] The main control unit CPU uses ARMSTM32, and the peripheral port is physically connected to the encoder and pressure sensor to obtain the position of the moving contact and receive the target pressure set by the pressure rod. The pressure is transmitted to the converter unit via optical fiber. The converter unit is an H-bridge converter. Electromagnetic attraction or electromagnetic repulsion is generated by changing the direction of the current in the winding. Four independent main control units are respectively set for control of the four windings. When closing, to ensure rapid closing, the two upper windings generate electromagnetic attraction to attract the permanent magnet, and the two lower windings generate electromagnetic repulsion to repel the permanent magnet, thereby ensuring the shortest closing time. When the moving contact and the static contact are about to contact, in order to reduce the speed of the moving contact and reduce the collision force, the two upper windings become electromagnetic repulsion and the two lower windings become electromagnetic attraction. Similarly, when the circuit breaker needs to be opened, the upper winding generates a larger electromagnetic repulsion and the lower winding generates electromagnetic attraction. By rationally configuring the current sizes of the four three-phase windings, the circuit breaker operates in the most efficient and energy-saving manner.

[0011] The beneficial effects of the present invention are:

[0012] (1) The three-phase moving contact connecting rod is innovatively controlled in two degrees of freedom, axial and pitch, to ensure the synchronization of the three-phase contact closing. In order to solve the problem of loose closing caused by relying solely on position sensors, a pressure detection mechanism is set up, and pressure-assisted control is innovatively adopted. When the moving and static contacts are not in contact, the position information is used to quickly control the closing. After the moving and static contacts are closed, the pressure sensors set at both ends of the pressure transmission rod input the real-time pressure value to the main control unit CPU, converting the system's position control into pressure control. This improves the reliability of the vacuum circuit breaker and effectively solves the problems of contact bounce and loose contact that are difficult to solve in traditional vacuum circuit breaker systems.

[0013] (2) The magnetic levitation technology is introduced into the vacuum circuit breaker system. The variable current direction characteristic of the H-bridge converter is innovatively utilized to control each electromagnetic winding individually, so that it can generate attraction or repulsion according to different working conditions. By dynamically adjusting the direction and magnitude of the electromagnetic force in the four windings, the vacuum circuit breaker contacts can be accurately and quickly closed.

[0014] (3) The innovative introduction of a micro-displacement amplification structure in the vertical direction utilizes the elastic deformation of the flexible hinge to amplify the input displacement equivalently to 6 times the original value, thereby reducing the power consumption of the circuit breaker and achieving good economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural schematic diagram of the magnetic levitation vacuum circuit breaker system of the present invention.

[0016] Figure 2 A top view of the integrated connecting rod and fixed beam structure of the magnetic levitation vacuum circuit breaker of the present invention.

[0017] Figure 3 Structural diagram of the operating mechanism of the magnetic levitation vacuum circuit breaker of the present invention.

[0018] Figure 4 This is a working mechanism diagram of the magnetic levitation vacuum circuit breaker system in the fast-closing state of the present invention.

[0019] Figure 5 This is a block diagram of the pressure closed-loop control of the magnetic levitation vacuum circuit breaker operating system of the present invention.

[0020] Figure 6 This is a program flow chart of the magnetic levitation machine vacuum circuit breaker operating system of the present invention.

[0021] In the figure: 1 upper conductive bar, 2 vacuum interrupter, 2-1 electrostatic rod, 2-2 static contact, 2-3 moving contact, 2-4 moving pole, 3 insulator, 4 fixed beam, 5a upper electromagnetic winding, 5b lower electromagnetic winding, 6 pressure transmission rod, 7 pressure sensor, 8 permanent magnet mover, 9 insulating housing, 10 lower conductive bar, 11 position sensor, 12 lever mechanism, 13 converter unit, 14 main control unit. DETAILED DESCRIPTION

[0022] The present invention will be described in further detail below with reference to the accompanying drawings.

[0023] like Figure 1 , Figure 2 As shown, a magnetic levitation vacuum circuit breaker operating system of the present invention includes a permanent magnet mover 8, bidirectional parallel electromagnetic windings 5a and 5b, a lever structure 12, and a main control unit 14. The main structure of the circuit breaker includes a lever mechanism 12, a pressure transmission rod 6, a permanent magnet mover 8 and a three-phase electromagnetic winding. The axial height between the pressure transmission rod 6 and the fixed beam 4 is consistent with the gap between the static contact 2-2 and the moving contact 2-3, which determines the maximum stroke of the permanent magnet. The upper end surface of the pressure transmission rod is a disc-shaped structure, and four orthogonally distributed pressure sensors 7 are provided. The electromagnetic windings 5a and 5b are connected to the converter unit 13. Bidirectional electromagnetic force is generated according to actual conditions to drive the permanent magnet to drive the connecting rod to drive the vertical movable shaft to move in the movable shaft through-hole on the fixed beam 4.

[0024] like Figure 3 、 Figure 4 、 Figure 5 、 Figure 6 As shown, the operating mechanism of the present invention is as follows: the main control unit first obtains the current position state through the position sensor and the pressure sensor, and then reads the target setting δ ref 、p ref , determine the motion mode of the permanent magnet mover, first regulate the converter unit to complete the two-degree-of-freedom position control of the permanent magnet mover, when the position sensor information reaches the set height δ refAfter that, the main control unit regulates the converter unit and changes the two-degree-of-freedom position control mode to the pressure control mode. Figure 5 The detailed steps are as follows:

[0025] Step 1: Fast closing mode: First, determine the pressure p between the contacts when they are tightly closed by experiment. ref In the fast closing mode, in order to ensure the rapid closing, the upper electromagnetic winding generates electromagnetic attraction, and the lower electromagnetic winding passes opposite current to generate electromagnetic repulsion, forming a combined force twice as large as the electromagnetic attraction. Since the moving and static contacts are not in contact at this time, position information is used for closed-loop control, and the pressure sensor value is 0. Since the distance between the pressure transmission rod and the fixed beam is consistent with the opening distance of the moving and static contacts, which is δ, when the moving contact moves δ mm and begins to contact the static contact, the permanent magnet mover position reaches the set height δ ref At this time, the control mode is changed from position control to pressure control. At this time, the pressure sensor value p starts to increase from 0. The PI pressure control strategy is adopted to provide a real-time reference for the pull-in current. Based on the real-time monitored pull-in current, the duty cycle of the converter unit is controlled and the magnitude and direction of the current in the winding are adjusted so that the upper electromagnetic winding forms an electromagnetic attraction and the lower electromagnetic winding forms an electromagnetic repulsion until the pressure sensor value reaches p ref At this time, the moving and static contacts have completed close attraction.

[0026] Step 2, suction maintenance mode: control the value of the pressure sensor to always be p ref , so that it meets the requirement of tight attraction of circuit breaker contacts. Since the electromagnetic force required to maintain the attraction after the contacts are attracted is not large, and because the permanent magnet mover rises, the air gap between it and the lower electromagnetic winding becomes larger. In order to reduce energy consumption, the lower winding is cut off so that it no longer provides electromagnetic repulsion. During the attraction process, pressure deviation and PI control strategies are used to obtain real-time attraction current reference. Combined with the real-time current sensor to measure the current value, the current inner loop PI control is used to control the duty cycle of the upper electromagnetic winding converter unit, adjust the current and electromagnetic attraction of the upper electromagnetic winding, and maintain stable attraction of the circuit breaker contacts.

[0027] Step 3, opening and decoupling mode: The main control unit sends an opening signal to the converter. In order to avoid the current in the circuit causing welding to the contacts due to the slow opening speed, the converter that controls the upper electromagnetic winding generates a reverse current, so that the upper electromagnetic winding changes from electromagnetic attraction to output electromagnetic repulsion. The lower electromagnetic winding is re-energized to generate electromagnetic attraction and operate at full duty cycle until the pressure sensor value changes from p ref Becomes 0, at which point the contacts are separated and switched to position control mode until the integrated connecting rod falls.

Claims

1. A synchronous operating mechanism for an electromagnetic vacuum circuit breaker with pressure-assisted regulation, characterized in that: It includes a pressure-assisted control structure and a two-winding synchronous operating mechanism; the pressure-assisted control structure includes a pressure transmission rod, a pressure sensor, a position sensor, a permanent magnet mover, and an integrated connecting rod to complete the tight attraction of the moving and static contacts of the circuit breaker; the two-winding synchronous operating mechanism includes an electromagnetic winding, a main control unit, and a converter unit to complete the horizontal movement and rise of the integrated connecting rod, thereby achieving the smoothing of the three-phase asymmetry of the line current caused by the asynchronous closing; the pressure transmission rod adopts a right-angle structure, is located on both sides of the permanent magnet mover, and is fixedly connected to the permanent magnet mover, and the pressure transmission rod is fixed to the permanent magnet mover. The gap between the rod and the fixed beam is consistent with the gap between the moving and static contacts in the vacuum interrupter, which is δ. The upper end face of the pressure transmission rod is a disc-shaped structure, with four orthogonally distributed pressure sensors on both sides. The pressure sensors are used to measure the pressure between the pressure transmission rod and the fixed beam after the permanent magnet mover drives the pressure transmission rod to rise; the permanent magnet mover is integrally connected with the integral connecting rod and the pressure transmission rods on the left and right sides, and is placed under the electromagnetic winding, and drives the integral connecting rod, the pressure transmission rod and the moving and static contacts in a linked manner to open / close the moving and static contacts; three pressure sensors are set on the fixed beam. A moving rod is through-hole, and the integral connecting rod is fixedly connected to the moving and static contacts in the vacuum interrupter through the moving rod through-hole. The integral connecting rod includes a vertical moving rod and a horizontal connecting rod. After the vertical moving rod passes through the moving rod through-hole, it is integrally connected through the horizontal connecting rod to achieve integral movement; the electromagnetic winding is respectively fixed to the fixed crossbeam and the bottom of the circuit breaker. Each electromagnetic winding has 16 N / S arranged moving windings inside. The electromagnetic winding is a DC excitation winding, which is connected to the converter unit. The electromagnetic winding is controlled by the converter unit and can generate electromagnetic excitation according to the opening / closing speed requirements. Suction can also generate electromagnetic repulsion to coordinately control the movement of the permanent magnet mover; the main control unit CPU uses ARMSTM32, and its peripheral ports are physically connected to the position sensor and pressure sensor to obtain the position information of the moving contact, receive the target pressure set by the pressure transmission rod, and transmit it to the converter unit through optical fiber. The converter unit is an H-bridge converter with an embedded current sensor, which collects current in real time and transmits it to the main control unit, changes the direction of the current in the electromagnetic winding, and generates electromagnetic attraction or electromagnetic repulsion. Four independent main control units are set for the four electromagnetic windings for control.

2. The electromagnetic vacuum circuit breaker synchronous operating mechanism with pressure-assisted regulation according to claim 1, characterized in that: The operating mechanism of the present invention includes three working modes: Fast closing mode: First determine the pressure p between the moving and static contacts when they are tightly closed. ref In the fast closing mode, to ensure the rapid closing, the upper electromagnetic winding generates electromagnetic attraction, and the lower electromagnetic winding passes opposite currents to generate electromagnetic repulsion, forming a combined force twice as large as the electromagnetic attraction. At this time, the moving and static contacts are not in contact, and position information is used for closed-loop control, and the pressure sensor value is 0. Since the distance between the pressure transmission rod and the fixed beam is consistent with the distance between the moving and static contacts, which is δ, when the moving contact moves δ mm and begins to contact the static contact, the position of the permanent magnet mover reaches the set height δ ref At this time, the control mode is changed from position control to pressure control. At this time, the pressure sensor value p starts to increase from 0. The PI pressure control strategy is adopted to provide a real-time reference for the pull-in current. Based on the real-time monitored pull-in current, the duty cycle of the converter unit is controlled to adjust the magnitude and direction of the current in the electromagnetic winding so that the upper electromagnetic winding forms an electromagnetic attraction and the lower electromagnetic winding forms an electromagnetic repulsion until the pressure sensor value reaches p ref At this time, the moving and static contacts have completed close attraction; Suction maintenance mode: the value of the control pressure sensor is always p ref Because the electromagnetic force required to maintain the dynamic and static contacts after they are closed is not large, and the permanent magnet mover rises, the air gap between it and the lower electromagnetic winding increases. During the closing process, a pressure deviation and PI control strategy are used to obtain a real-time closing current reference. Combined with the current sensor to measure the real-time current value, the current inner loop PI control is used to control the duty cycle of the converter unit of the upper electromagnetic winding, adjust the current and electromagnetic attraction of the upper electromagnetic winding, and maintain stable closing of the circuit breaker contacts. Opening and uncoupling mode: The main control unit sends an opening signal to the converter unit. In order to avoid the current in the circuit from welding the contacts due to the slow opening speed, the converter unit that controls the upper electromagnetic winding generates a reverse current, so that the upper electromagnetic winding changes from electromagnetic attraction to output electromagnetic repulsion. The lower electromagnetic winding is re-energized to generate electromagnetic attraction and operate at full duty cycle until the pressure sensor value changes from p ref Becomes 0, at which point the contacts are separated and switched to position control until the integrated connecting rod falls.

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