Three-stage energy-saving control electromagnetic coil device and control method thereof

Abstract

The present application relates to electromagnetic relay and contactor technical field, disclose a three section type energy saving control's electromagnetic coil device and control method thereof, including first winding, second winding, movable iron core and controller;Control method is: in first preset time interval, control first winding and second winding is simultaneously sustained conduction, drive movable iron core to the closing position movement;After entering second preset time interval after first preset time interval ends, first winding keeps energized, controller to the power switch element that is in series in second winding loop outputs duty cycle presents the modulation driving signal of decrement, so that second winding intermittent energization;After second preset time interval ends, control power switch element cut-off to open second winding, only rely on first winding energization maintains attraction state.The present application eliminates the current mutation and mechanical impact when winding switching, avoids mechanical contact wear, reduces system power consumption and temperature rise while ensuring reliable attraction.

Description

Technical Field

[0001] This invention relates to the field of electromagnetic relays and contactors, specifically to a three-stage energy-saving control electromagnetic coil device and its control method. Background Technology

[0002] In electrical products such as electromagnetic contactors and relays, the coil, as the core energy conversion component, generates electromagnetic force when energized to drive the moving iron core to engage. To reduce power consumption during the steady-state holding phase, existing technologies typically employ a dual-winding energy-saving structure, which uses mechanical auxiliary contacts to switch between the starting and holding windings. However, this method, relying on mechanical contacts for winding circuit switching, inevitably suffers from contact mechanical wear and arcing issues when interrupting current, thus limiting the long-term operational reliability of the device.

[0003] Furthermore, existing dual-winding coils generally employ a two-stage control logic: the dual windings operate in parallel during the startup phase, followed by a direct disconnection of the startup winding to switch to a single winding for holding. This control method, which directly cuts off the high-current circuit, lacks a smooth transition mechanism, causing a sudden drop in the total electromagnetic force. This can lead to core bouncing and mechanical shock, affecting not only the lifespan of the mechanical structure but also resulting in insufficient holding force margin at the moment of switching. Consequently, the device is prone to unexpected release actions when faced with instantaneous fluctuations in external grid voltage. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a three-stage energy-saving control electromagnetic coil device and its control method. This solves the problems of low reliability caused by wear and arcing of mechanical contacts during winding switching in existing dual-winding electromagnetic coil devices, and the mechanical shock caused by sudden electromagnetic force changes and insufficient holding force margin in traditional two-stage direct switching logic.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] The first aspect of the present invention provides a three-stage energy-saving control electromagnetic coil device, comprising a first winding, a second winding, a movable iron core, a main switch, and a controller; the controller is electrically connected to the first winding and the second winding, and includes a pulse width modulation module, a timing control module, and a power switching element; the first winding and the second winding are connected in parallel; the power switching element is connected in series in an independent power supply circuit of the second winding, and the output terminal of the pulse width modulation module is connected to the control terminal of the power switching element; the main switch is disposed in the front-end circuit of the power supply input.

[0007] The controller receives the main switch closing command and enters a first preset time interval, controlling the first winding and the second winding to be in a continuously conducting state. During this stage, both windings are simultaneously fully charged and conducting, utilizing the low impedance characteristics of the second winding to generate a large current, exciting a peak state of the combined electromagnetic force, driving the movable iron core to overcome static resistance and move rapidly towards the closed position.

[0008] After the first preset time interval ends, a second preset time interval begins, during which the first winding remains energized. The timing control module triggers the pulse width modulation module to output a modulation drive signal with a decreasing duty cycle to the power switching element. During this stage, the power switching element performs high-frequency periodic switching. Based on the inherent inductance characteristics of the electromagnetic coil and the physical law that inductor current cannot change abruptly, the actual equivalent average current in the second winding smoothly decreases as the duty cycle decreases linearly.

[0009] This progressive electromagnetic force decay control provides a continuous and sufficient holding force margin for the movable iron core, eliminating mechanical shocks caused by sudden current changes and preventing unexpected release of the movable iron core before it stabilizes. After the second preset time interval ends, the power switching element is turned off, disconnecting the second winding and keeping the first winding energized. During this stage, the system relies on the steady-state electromagnetic force generated by the high-impedance first winding energized to balance the mechanical reaction force, maintaining the closure of the movable iron core and reducing power consumption and temperature rise during prolonged coil energization.

[0010] Furthermore, the device also includes a frame; the first winding and the second winding are independently wound around the outside of the frame and connected to an external power supply circuit; the movable iron core is movably inserted into the cavity inside the frame; the number of turns of the first winding is greater than the number of turns of the second winding, and the wire diameter of the first winding is smaller than the wire diameter of the second winding.

[0011] Furthermore, the controller also includes a current detection module connected in series in the main circuit. During the first preset time interval, the controller controls the current detection module to collect current values ​​in the main circuit and calculates the current decrease rate based on the collected current values.

[0012] Based on the physical phenomenon that as the movable iron core approaches the closed position, the internal working air gap of the electromagnetic device decreases, the magnetic permeability of the magnetic circuit increases, and the equivalent inductance of the coil increases, thereby hindering the rise of current, the main circuit current curve exhibits a recognizable downward characteristic when it reaches the vicinity of the pull-in position, the controller terminates the first preset time interval when it determines that the rate of current decline exceeds a preset rate threshold; the preset rate threshold is the average current inflection point slope characteristic calibrated at the instant the movable iron core closes under standard operating voltage.

[0013] Furthermore, the initial duty cycle setting range of the modulation drive signal with decreasing duty cycle is 70% to 90%; after the second preset time interval ends, the duty cycle value of the modulation drive signal drops to 0.

[0014] Furthermore, a freewheeling protection branch is connected in series in the independent power supply circuit of the second winding; the freewheeling protection branch releases the inductive energy of the second winding during the power switching element's turn-off period, limiting the reverse impulse voltage across the power switching element.

[0015] A second aspect of the present invention provides a control method for a three-stage energy-saving control electromagnetic coil device, applied to the three-stage energy-saving control electromagnetic coil device described in the first aspect of the present invention, comprising the following steps:

[0016] Upon receiving the main switch closing command, the system enters a first preset time interval and controls the first winding and the second winding to be in a continuously conducting state.

[0017] After the first preset time interval ends, the second preset time interval begins, the first winding is kept energized, and the timing control module triggers the pulse width modulation module to output a modulation drive signal with a decreasing duty cycle to the power switching element.

[0018] The power switching element performs a periodic switching action according to the modulation drive signal, and the second winding enters an intermittent energized state;

[0019] After the second preset time interval ends, the power switching element is controlled to turn off, the second winding is disconnected, and the first winding is controlled to remain energized.

[0020] Furthermore, within the first preset time interval, the current detection module is controlled to collect the current value in the main circuit, and the current drop rate is calculated based on the collected current value.

[0021] When the current drop rate exceeds a preset rate threshold, the movable iron core is determined to have reached the attraction position, the first preset time interval is terminated, and the second preset time interval is triggered.

[0022] The preset rate threshold is the slope characteristic of the average current inflection point at the instant the movable iron core closes, calibrated under standard operating voltage.

[0023] Further, the step of calculating the current decrease rate based on the collected current value includes:

[0024] Obtain the current value collected at the current moment and the current value collected at the previous sampling moment adjacent to the current moment;

[0025] The current decrease rate is obtained by dividing the difference between the current value collected at the previous sampling time and the current value collected at the current time by the time interval between two adjacent sampling operations.

[0026] Further, controlling the timing control module to trigger the pulse width modulation module to output a modulation drive signal with a decreasing duty cycle to the power switching element includes:

[0027] At the beginning of the second preset time interval, the pulse width modulation module is controlled to output a modulation drive signal with an initial duty cycle;

[0028] The duty cycle value of the modulation drive signal decreases linearly with the running time according to a preset slope;

[0029] At the end of the second preset time interval, the pulse width modulation module is controlled to stop outputting the modulation drive signal, and the duty cycle value of the modulation drive signal is reduced to 0.

[0030] Furthermore, the length of the first preset time interval is the travel time of the movable iron core to move to a near-closed position;

[0031] The time interval of the second preset time interval is the time required for the electromagnetic force of the system to reach a stable state after the movable iron core is closed in place;

[0032] The modulation frequency of the modulation drive signal output by the pulse width modulation module is higher than the mechanical response frequency of the movable iron core.

[0033] This invention provides a three-stage energy-saving control electromagnetic coil device and its control method. It has the following beneficial effects:

[0034] 1. In the transition phase, the present invention controls the first winding to remain energized and outputs a modulated drive signal with a decreasing duty cycle to the power switching element controlling the second winding; this causes the equivalent current of the second winding to decrease smoothly, avoiding the sudden change in total electromagnetic force caused by directly cutting off the starting winding, thereby eliminating the mechanical bounce and contact jitter of the movable iron core when it is close to the closed position, and reducing mechanical shock.

[0035] 2. This invention collects the current value of the main circuit in real time during the startup phase and calculates the current drop rate. When the drop rate exceeds the preset rate threshold, the startup phase is terminated and the transition phase is triggered. It utilizes the physical characteristic that the closure of the movable iron core causes the equivalent inductance of the coil to increase, thereby leading to a drop in current. This can accurately identify the actual closed state of the iron core, overcome the defects of single fixed timing control that are affected by external power supply voltage fluctuations or internal mechanical damping changes, and improve the accuracy of state switching.

[0036] 3. During the holding phase, the present invention disconnects the low-impedance second winding by a power switching element, relying solely on the high-impedance first winding to maintain the closure of the movable iron core. This control logic limits the overall steady-state holding current of the coil, reducing power consumption and temperature rise during long-term operation of the device. At the same time, the use of solid-state power switching elements to replace traditional mechanical auxiliary contacts for winding circuit switching avoids the arcing and physical wear problems caused by mechanical contacts cutting off inductive loads, thereby improving the electrical reliability and service life of the device. Attached Figure Description

[0037] Figure 1 This is a three-dimensional structural diagram of the electromagnetic coil device of the present invention;

[0038] Figure 2 This is a front view of the electromagnetic coil device of the present invention;

[0039] Figure 3 This is a structural diagram of the electromagnetic coil device of the present invention;

[0040] Figure 4 This is a schematic diagram of the control method of the present invention.

[0041] The components include: 1. skeleton; 2. first winding; 3. second winding; 4. movable iron core; and 5. controller. Detailed Implementation

[0042] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0043] See attached document Figure 1 -Appendix Figure 3 This invention provides a three-stage energy-saving control electromagnetic coil device, comprising a frame 1, a first winding 2, a second winding 3, a movable iron core 4, and a controller 5. The first winding 2 and the second winding 3 are independently wound around the outside of the frame 1. The first winding 2 has a high number of turns and a fine wire diameter. The second winding 3 has a low number of turns and a thick wire diameter. The movable iron core 4 is movably inserted into a cavity inside the frame 1. The controller 5 is mounted on the frame 1 and electrically connected to both the first winding 2 and the second winding 3.

[0044] The controller 5 internally includes a pulse width modulation module, a timing control module, a current detection module, a power switching element, and a main switch. The first winding 2 and the second winding 3 are connected in parallel and then connected to an external power supply circuit. The power switching element is connected in series in the independent power supply circuit of the second winding 3. The output terminal of the pulse width modulation module is connected to the control terminal of the power switching element. The current detection module is connected in series in the main circuit of the coil. The main switch is located in the front-end circuit of the power input. In this embodiment, the independent power supply circuit of the second winding 3 is also equipped with a freewheeling protection branch, which is used to release the inductive energy of the second winding 3 during the power switching element's turn-off period and limit the reverse impulse voltage across the power switching element.

[0045] See attached document Figure 1 Appendix Figure 2 and attached Figure 4 This invention provides a three-stage energy-saving control method, comprising the following steps:

[0046] S10, Receive the main switch closing command and enter 0 to 0 During a specific time interval (a first preset time interval), the first winding 2 and the second winding 3 are simultaneously kept in a continuously conducting state. Within this time interval, the first winding 2 and the second winding 3 together generate a combined electromagnetic force, driving the movable iron core 4 to move from its initial position to its closed position. The time length is configured as the travel time for the movable iron core 4 to move to a near-closed position;

[0047] S20, from 0 to Within the specified time interval, the control current detection module collects the current value in the main circuit of the coil in real time, and the controller 5 calculates the current drop rate based on the collected current value. When the current drop rate exceeds the preset rate threshold, it is determined that the movable iron core 4 has reached the pull-in position and the process is stopped from 0 to 1. Time interval;

[0048] S30, at arrival time Alternatively, the start of engagement can be determined based on the rate of current decrease. to During the second preset time interval (the period between two preset time intervals), while the main switch remains closed, the first winding 2 remains energized through a continuous conduction path. The timing control module triggers the pulse width modulation module to output a modulation drive signal with a decreasing duty cycle to the power switching element.

[0049] S40, the power switching element performs periodic switching actions according to the modulation drive signal, causing the second winding 3 to enter an intermittent energized state. The movable iron core 4 moves under the condition of decreasing total electromagnetic force and is stably closed within the cavity. to The time interval is configured as the time required for the electromagnetic force of the system to reach a stable state after the movable iron core 4 is closed in place;

[0050] S50, at arrival time Then, the control pulse width modulation module stops outputting the modulation drive signal, and the power switching element is in the off state to disconnect the power supply circuit of the second winding 3. With the main switch closed, the first winding 2 remains energized, and the movable iron core 4 is maintained in the closed state by the single electromagnetic force generated by the first winding 2.

[0051] See attached document Figure 1 -Appendix Figure 3 The following is a detailed description of the structural diagram of the electromagnetic coil device according to an embodiment of the present invention. The present invention provides a three-stage energy-saving control electromagnetic coil device, the hardware body of which is a dual-winding electromagnetic assembly. In this embodiment, the frame 1 serves as the supporting structure for the first winding 2 and the second winding 3, and its interior has a through cavity through which a movable iron core 4 passes. The movable iron core 4 is inserted into the cavity inside the frame 1 with a clearance fit. In the unenergized state, the movable iron core 4 is in its initial position due to the static thrust of the mechanical spring. In this embodiment, when the coil is energized and generates an electromagnetic force greater than the aforementioned mechanical thrust, the movable iron core 4 undergoes a linear displacement from its initial position to its closed position along the guide inner wall of the cavity, thereby achieving the attraction action. It should be noted that the specific assembly position of the mechanical spring and the surface treatment of the guide inner wall can be configured by those skilled in the art according to the mechanical structure requirements of conventional electromagnetic contactors; the mechanical arrangement is well-known in the field and will not be elaborated further here.

[0052] The outer space of the frame 1 is used to support the coil windings. The windings are divided into a first winding 2 and a second winding 3 according to their physical characteristics and electromagnetic functions. Both the first winding 2 and the second winding 3 are independently wound on the outside of the frame 1. To achieve the differentiated functions of low-power maintenance and high-current start-up, the first winding 2 and the second winding 3 exhibit different hardware characteristics in terms of physical parameters.

[0053] The first winding 2, also known as the holding winding, is made of copper wire with a high number of turns and a small wire diameter. Preferably, the first winding 2 corresponds to the N1 winding in the coil specifications, with 2800 turns and a wire diameter of 0.125mm, resulting in a DC resistance of approximately 226.7Ω. Based on Ohm's law, because the first winding 2 has a high DC impedance value that meets design requirements, the steady-state current flowing through it is at the rated holding level when energized. Therefore, it exhibits low active power consumption and low temperature rise characteristics. The steady-state electromagnetic force it generates is used to counteract the mechanical reaction force to maintain the movable iron core 4 in the closed position.

[0054] The second winding 3, also known as the starting winding, is wound with wire characterized by a low number of turns and a large wire diameter. In specific implementation, the second winding 3 corresponds to the N2 winding in the coil specification, with 550 turns and a wire diameter of 0.335mm, resulting in a DC resistance of approximately 6.2Ω. These DC impedance properties allow the second winding 3 to withstand the rated transient starting current upon energization, thereby generating a combined electromagnetic force with a corresponding peak amplitude. This electromagnetic force overcomes the static resistance of the movable iron core 4 in its initial position to achieve rapid engagement.

[0055] The controller 5 is housed within the junction box of the frame 1 and is electrically connected to the first winding 2 and the second winding 3, respectively. The specific electrical connection paths between the controller 5 and the first winding 2 and the second winding 3 can be described in detail as follows:

[0056] S101, construct the dual-winding power supply branch node. In this embodiment, the input terminals of the first winding 2 and the second winding 3 are connected in parallel to form a common terminal, defined as common terminal C, which is connected to the external power supply input circuit. A main switch is set in the front-end circuit of the power supply input to control the power supply on and off of the overall device. The other end of the first winding 2 is defined as terminal M, forming a continuous conduction path directly connected to the return circuit. The other end of the second winding 3 is defined as terminal A, connected to an independent controlled power supply branch.

[0057] S102, Configure a contactless power switch node. The controller 5 internally houses a power switch element, which is connected in series in the independent controlled power supply branch of the second winding 3. Specifically, the power switch element is physically implemented using a metal-oxide-semiconductor field-effect transistor (MOSFET). Using a MOSFET as the electronic switch element helps avoid the arcing phenomenon that occurs when traditional mechanically assisted contacts interrupt current, thereby reducing the risk of contact wear and extending the device's lifespan. In this embodiment, the controlled power supply branch of the second winding 3 is also configured with a freewheeling protection branch. This branch releases the inductive energy of the second winding 3 during the off-state of the power switch element and limits the reverse surge voltage across the power switch element. The freewheeling protection branch can be implemented using one or more combinations of a freewheeling diode, a RC snubber circuit, or a transient voltage suppressor.

[0058] S103 establishes the control logic signal link node. Controller 5 internally includes a pulse width modulation (PWM) module and a timing control module. The output of the PWM module is electrically connected to the control terminal of the power switching element. For example, the output of the PWM module is directly connected to the gate of the semiconductor field-effect transistor to send drive signals to the power switching element according to preset duty cycle parameters. The signal output of the timing control module is connected to the PWM module to issue timing commands for switching operating states.

[0059] S104, Configure a current feedback detection node. To achieve more accurate state determination, the device in this embodiment also includes a current detection module. The current detection module is connected in series in the main circuit of the coil device to collect the coil current value in real time. The data output terminal of the current detection module is connected to the controller 5. When the controller 5 calculates that the current drop rate exceeds a preset threshold based on the collected data, it can help determine that the movable iron core 4 has been attracted into place. Through the construction of the above electrical nodes, the controller 5 has the basis for independently injecting and modulating electromagnetic energy into the dual windings in real time.

[0060] See attached document Figure 1 Appendix Figure 2 and attached Figure 4 The following is a detailed explanation of the specific logic of the startup phase in the three-stage energy-saving control method of this embodiment. In this embodiment, the startup phase mainly uses a combination of dual-winding full-voltage excitation and current characteristic detection to enable the movable iron core 4 to complete the attraction action within a set time, and corrects the phase switching time according to the actual current changes. This part of the control logic can be specifically decomposed into the following execution steps:

[0061] S201 executes the dual-winding full-voltage excitation operation. Upon receiving the main switch closing command, controller 5 enters state 0 to... The time interval (this interval is the first preset time interval). In this embodiment, the main switch is in the closed state, and the controller 5 outputs a continuous drive signal to the control terminal of the power switching element, so that the power switching element remains in the continuously conducting state. In this circuit structure, the first winding 2 and the second winding 3 are connected in parallel to the power supply circuit. Since the second winding 3 has a DC impedance that meets the set requirements, a rated large-value transient starting current is generated in the main circuit. Under the action of the transient starting current, the first winding 2 and the second winding 3 jointly generate a combined electromagnetic force at its peak state. This combined electromagnetic force can overcome the static resistance of the mechanical components, thereby driving the movable iron core 4 to accelerate towards the closed position.

[0062] S202, Configure the time parameters for the startup phase. Time parameters The specific physical meaning is the time required for the movable iron core 4 to move from its initial position to a near-closed position. As a preferred method, the time parameter... The time duration is set to 15ms. The technical purpose of setting this time duration is twofold: firstly, to ensure that the movable iron core 4 obtains sufficient kinetic energy to complete the main body's mechanical displacement; and secondly, to control the continuous energizing time of the high current in the second winding 3, thereby reducing the risk of overload due to heat accumulation in the low-impedance coil. For the specific start-up time and stroke matching calculations for coils of different specifications, those skilled in the art can combine conventional mechanical load curves to perform parameter tuning. Parameter matching is a well-known technique in this field and will not be elaborated upon here.

[0063] S203 performs adaptive state switching based on current characteristics. This is to prevent fixed-time switching caused by supply voltage fluctuations or changes in mechanical damping. Unable to accurately match the actual engagement state, controller 5 is in the range of 0 to... The synchronous operation status monitoring logic operates within a specific time interval. As the movable iron core 4 moves closer to the closed position, the internal working air gap of the electromagnetic device gradually decreases, leading to an increase in magnetic permeability and equivalent inductance of the coil. This increase in inductance hinders further current rise, and a identifiable downward trend appears in the main circuit current curve when the movable iron core 4 reaches near the pull-in position. Based on this physical phenomenon, the current detection module collects the current value in the main circuit of the coil in real time according to a set sampling frequency and transmits it to the controller 5. In this embodiment, the time interval between two adjacent sampling operations is configured to be less than the startup phase time parameter. This enables controller 5 to be able to operate from 0 to... Multiple consecutive sampling points are obtained within a time interval; as an optional method, the sampling period is configured in the range of 50μs to 500μs.

[0064] S204 calculates characteristic parameters and outputs the judgment result. Controller 5 calculates the current decrease rate based on continuously collected current values. Assuming a fixed sampling period, the calculation logic for the current decrease rate can be expressed as:

[0065] ;

[0066] in, This indicates the rate of decrease of the current in the main circuit of the coil;

[0067] This represents the current value collected at the current moment;

[0068] This represents the current value collected at the previous sampling time adjacent to the current time.

[0069] This indicates the time interval between two consecutive sampling operations.

[0070] To prevent the processor from performing division by zero or numerical calculation errors within a single clock cycle, a minimum time step limit is preset in the control logic, i.e., the limit condition is: >0 and greater than the single instruction cycle of controller 5.

[0071] The technical purpose of this calculation formula is to extract the slope characteristics of the current curve. Controller 5 will then use the calculated current drop rate... The value is compared with a preset rate threshold stored internally. This preset rate threshold is calibrated by extracting the average current inflection point slope characteristics at the moment of closure through multiple closure tests of the coil device under standard operating voltage. To improve the system's anti-interference capability, the decision logic adopts a multi-dimensional approach: when judging the current drop rate... If the preset rate threshold is exceeded, or the system runtime reaches the aforementioned time parameter, When any condition is met, it indicates that the movable iron core 4 has reached the engaging position. At this time, the controller 5 outputs an action completion signal, stopping the operation from position 0 to 1. The system determines the time interval and triggers the control flow to enter the next time interval. This mechanism, which relies on physical feature feedback, helps improve the response accuracy of the device under different operating conditions.

[0072] See attached document Figure 1 Appendix Figure 2 and attached Figure 4 The following is a detailed explanation of the specific logic of the transition phase in the three-stage energy-saving control method of this embodiment. In this embodiment, the transition phase uses pulse width modulation to gradually adjust the equivalent energized energy of the second winding 3, so as to reduce the impact of the sudden change in total electromagnetic force at the end of the start-up phase on the closing stability of the movable iron core 4. This part of the control logic can be specifically decomposed into the following execution steps:

[0073] S301, maintain the basic conducting state of the first winding 2. At the system operation arrival time... Alternatively, after determining the completion of the engagement action based on the rate of current decrease, controller 5 enters... to The time interval (which is the second preset time interval). With the main switch closed, the first winding 2 is connected to the external power supply circuit through its continuous conduction path and remains energized, thereby continuously providing the basic holding force.

[0074] S302 generates and outputs a decreasing modulation drive signal. Traditional two-stage control schemes directly disconnect the starting winding after the start-up phase, causing a step change in the total electromagnetic force of the system. If the mechanical components have not yet reached a steady state at this time, the rapid decrease in electromagnetic force poses a risk of causing the movable iron core 4 to bounce and the contacts to jitter. Therefore, in this embodiment, the timing control module, upon entering... The pulse width modulation module is triggered synchronously at all times, and a modulation drive signal with a decreasing duty cycle is output to the control terminal of the power switching element.

[0075] The mathematical relationship of this duty cycle decreasing logic can be expressed as:

[0076] ;

[0077] in, Indicates the current running time The real-time duty cycle value output by the pulse width modulation module;

[0078] Indicates time The timeframe refers to the initial duty cycle at the beginning of the transition phase.

[0079] This variable represents the current running time of the system.

[0080] Indicates the moment when the transition phase begins;

[0081] This indicates the moment when the transition phase ends.

[0082] To ensure the completeness of the control algorithm and prevent overflow, the system internally sets constraints on this logic: requiring... > To avoid division by zero errors and to limit runtime variables The range of values ​​is ≤t≤ To ensure that the duty cycle value is within a reasonable range.

[0083] The technical purpose of this calculation formula is to establish an energy injection model that decays linearly over time, with a predetermined slope in its linear decline process. As a preferred method, the initial duty cycle... The duty cycle is configured to range from 70% to 90%, and at the end of this transition phase, the final duty cycle value drops to 0%. In practice, the initial duty cycle... Set to 80%. The time interval for the transition phase, i.e. and The difference is configured as the time required for the electromagnetic force of the system to reach a stable state after the movable iron core 4 is closed in place, and this time interval is specifically set to 10ms.

[0084] S303, execute the energy smoothing attenuation action. After receiving the above-mentioned modulation drive signal, the control terminal of the power switching element performs a high-frequency cycle switching action according to the change of high and low levels, causing the second winding 3 to enter an intermittent energized state. In this embodiment, the modulation frequency of the pulse width modulation module is configured to be higher than the mechanical response frequency of the movable iron core 4, so that the equivalent average current of the second winding 3 can change continuously with the duty cycle; as an optional method, the modulation frequency is configured in the range of 1kHz to 20kHz. Due to the inherent inductance characteristics of the electromagnetic coil, based on the physical law that the inductor current cannot change abruptly, the actual equivalent average current in the second winding 3 will not undergo transient changes, but will show a smooth decreasing physical trend as the duty cycle value decreases linearly.

[0085] S304 maintains dynamic force balance and mechanical anti-vibration. As the equivalent average current of the second winding 3 decreases, the total resultant electromagnetic force generated by the first winding 2 and the second winding 3... to The system exhibits a smooth decreasing force state synchronously within the time interval. Through progressive electromagnetic force attenuation control, the system provides a holding force margin for the movable iron core 4 during the transition phase. This margin mechanism can reduce the mechanical shock caused by sudden current changes and resist transient voltage drops in the power supply network, preventing the movable iron core 4 from unexpectedly releasing before the system reaches steady state, thereby ensuring that the movable iron core 4 completes a stable closure within the cavity of the frame 1.

[0086] See attached document Figure 1 Appendix Figure 2 and attached Figure 4 The following is a detailed explanation of the specific logic of the holding phase in the three-stage energy-saving control method of this embodiment. In this embodiment, the holding phase disconnects the power supply circuit of the second winding 3 through a solid-state electronic switch and maintains the movable iron core 4 closed by utilizing the impedance characteristics of the first winding 2, thereby reducing energy consumption under long-term energization. This part of the control logic can be specifically decomposed into the following execution steps:

[0087] S401, execute the start-up loop cut-off action. When the system runtime reaches the aforementioned time... At this point, controller 5 determines that the transition phase has ended. In this embodiment, the timing control module inside controller 5 sends a stop command to the pulse width modulation module, and the pulse width modulation module immediately stops outputting modulation drive signals to the control terminal of the power switching element. Specifically, controller 5 sets the input signal to the control terminal of the power switching element to a low level, causing the physical state of the power switching element to change from periodic on / off to off. The independent power supply circuit of the second winding 3 is thus disconnected, causing the second winding 3 to exit the electromagnetic energy conversion process.

[0088] S402, Single-winding steady-state maintenance process. After the power switching element is turned off, the system enters the subsequent steady-state maintenance stage. At this time, the main switch remains closed, and the external power supply input forms a single continuous conducting loop only through the first winding 2. As the movable iron core 4 moves to the closed position within the cavity of the frame 1, the working air gap of the entire electromagnetic system decreases to the target closed size, and the corresponding magnetic circuit reluctance reaches the set state. Based on the fundamental laws of electromagnetism, under this set reluctance state, only the rated excitation current needs to be maintained to generate an electromagnetic force sufficient to counteract the static reaction force of the mechanical components. Therefore, the system relies on the steady-state electromagnetic force generated by the energization of the first winding 2 to balance the mechanical reaction force and maintain the closure of the movable iron core 4.

[0089] S403 achieves low power consumption and temperature rise limitation for the system. The first winding 2 possesses DC impedance physical characteristics that meet design requirements due to its high number of turns and fine wire diameter, allowing the rated steady-state current to flow when connected to an external power supply circuit. Based on the active power calculation principle of Joule's law, it is known that under constant supply voltage, the aforementioned DC impedance can limit the overall energy consumption rate of the coil. As a preferred method, calculated according to the aforementioned DC resistance parameters and under the same external supply voltage, the theoretical active power consumption of the first winding 2 during the holding phase is approximately 2.7% of the full-voltage conduction power consumption of the dual windings during the startup phase. Under different supply voltages, winding parameters, and power switching losses, the actual power consumption ratio during the holding phase can be calibrated through prototype testing. This low-power operation effectively suppresses the internal heat accumulation of the coil assembly during long-term energization, reduces the overall temperature rise index of the device, helps to delay the thermal aging process of the frame 1 and the enameled wire insulation layer, and improves the long-term electrical reliability of the electromagnetic coil device.

[0090] See attached document Figure 1 Appendix Figure 2 and attached Figure 4 In this embodiment, the aforementioned adaptive switching mechanism based on current characteristics can be broken down into the following steps for explanation:

[0091] The basic electrical data acquisition process for the coil main circuit current characteristics of S501 is established at the initial stage of system power-on. Controller 5 maintains a communication link with the current detection module to continuously acquire current. Preprocessing operations such as current sampling data and anti-aliasing filtering are directly executed using standard microcontroller parameter configuration.

[0092] S502, the system performs basic parameter extraction based on the collected current sampling data. Controller 5 obtains the real-time current decrease rate within the operating cycle through conventional differential logic processing, and the relevant calculation process proceeds steadily according to the preset standard time step.

[0093] S503, controller 5 executes phase switching decision logic based on the real-time current decrease rate. Assume... This indicates the rate of decrease of the current in the main circuit of the coil. This indicates the preset rate threshold for internal storage. The values ​​of the transient physical characteristics of the movable iron core 4 under standard operating voltage are taken. When the controller 5 determines that the logical relationship is satisfied... > When the movable iron core 4 has reached the engaging position, the controller 5 immediately stops the start-up phase timing and generates a phase switching command, prematurely ending the timing logic of the start-up phase and triggering the transition phase workflow where the pulse width modulation module outputs the modulation drive signal.

[0094] In summary, this embodiment, through the differentiated electromagnetic function configuration of the first winding 2 and the second winding 3, enables the second winding 3 to provide the rated starting electromagnetic force during the start-up phase, and enables the first winding 2 to provide a steady-state holding force with lower power consumption during the holding phase. Furthermore, through the cooperation of power switching elements, a pulse width modulation module, a timing control module, and a current detection module, the coil device can sequentially form a three-stage energy-saving control process: dual-winding full-voltage start-up, second winding 3 modulation attenuation, and first winding 2 individual holding. Therefore, while ensuring reliable engagement and stable closure of the movable iron core 4, it helps to reduce power consumption and temperature rise during prolonged coil energization.

Claims

1. A three-stage energy-saving control electromagnetic coil device, characterized in that, It includes a first winding (2), a second winding (3), a movable iron core (4), and a controller (5). The controller (5) is electrically connected to the first winding (2) and the second winding (3). The controller (5) is equipped with a pulse width modulation module, a timing control module, and a power switching element. The first winding (2) and the second winding (3) are connected in parallel. The power switching element is connected in series in the power supply circuit of the second winding (3). The output terminal of the pulse width modulation module is connected to the control terminal of the power switching element. The controller (5) receives a closing command and enters a first preset time interval, controlling the first winding (2) and the second winding (3) to be continuously conducting. After the first preset time interval ends, it enters a second preset time interval, controlling the first winding (2) to remain energized. The timing control module triggers the pulse width modulation module to output a modulation drive signal with a decreasing duty cycle to the power switching element. After the second preset time interval ends, it controls the power switching element to turn off and disconnect the second winding (3), controlling the first winding (2) to remain energized.

2. The electromagnetic coil device with three-stage energy-saving control according to claim 1, characterized in that, It also includes a frame (1) and a main switch. The first winding (2) and the second winding (3) are independently wound around the outside of the frame (1) and connected to the external power supply circuit. The main switch is set in the front end circuit of the power supply input. The movable iron core (4) is movably inserted into the cavity inside the frame (1). The number of turns of the first winding (2) is greater than the number of turns of the second winding (3). The wire diameter of the first winding (2) is smaller than the wire diameter of the second winding (3).

3. The electromagnetic coil device with three-stage energy-saving control according to claim 1, characterized in that, The controller (5) also includes a current detection module, which is connected in series in the main circuit. During the first preset time interval, the controller (5) controls the current detection module to collect the current value in the main circuit and calculates the current drop rate based on the collected current value. When the current drop rate exceeds the preset rate threshold, the controller (5) stops the first preset time interval. The preset rate threshold is the average current inflection point slope characteristic of the movable iron core (4) at the moment of closure calibrated under the standard working voltage.

4. The electromagnetic coil device with three-stage energy-saving control according to claim 1, characterized in that, The initial duty cycle of the modulation drive signal with decreasing duty cycle is set to a range of 70% to 90%. After the second preset time interval ends, the duty cycle value of the modulation drive signal drops to 0.

5. The electromagnetic coil device with three-stage energy-saving control according to claim 1, characterized in that, A freewheeling protection branch is connected in series in the power supply circuit of the second winding (3). The freewheeling protection branch releases the inductive energy of the second winding (3) during the power switching element is turned off, thereby limiting the reverse impulse voltage across the power switching element.

6. A control method for a three-stage energy-saving control electromagnetic coil device, characterized in that, An electromagnetic coil device for three-stage energy-saving control as described in any one of claims 1-5 includes the following steps: Upon receiving a closing command, the system enters the first preset time interval and controls the first winding (2) and the second winding (3) to remain continuously conducting. After the first preset time interval ends, the second preset time interval begins. The first winding (2) is kept energized. The timing control module triggers the pulse width modulation module to output a modulation drive signal with decreasing duty cycle to the power switching element. The power switching element performs a periodic switching action according to the modulation drive signal, and the second winding (3) enters an intermittent energized state; After the second preset time interval ends, the power switch element is controlled to cut off the second winding (3), and the first winding (2) is controlled to remain energized.

7. The control method for a three-stage energy-saving control electromagnetic coil device according to claim 6, characterized in that, Within the first preset time interval, the current value in the main circuit is collected by the current detection module in the controller (5), and the current drop rate is calculated based on the collected current value. When it is determined that the rate of decrease of the current exceeds the preset rate threshold, it is determined that the movable iron core (4) has reached the attraction position, the first preset time interval is terminated, and the second preset time interval is triggered. The preset rate threshold is the average current inflection point slope characteristic of the movable iron core (4) at the instant of closure, calibrated under standard working voltage.

8. The control method for a three-stage energy-saving control electromagnetic coil device according to claim 7, characterized in that, The step of calculating the current drop rate based on the collected current value includes: Obtain the current value collected at the current moment and the current value collected at the previous sampling moment adjacent to the current moment; The current decrease rate is obtained by dividing the difference between the current value collected at the previous sampling time and the current value collected at the current time by the time interval between two adjacent sampling operations.

9. The control method for a three-stage energy-saving control electromagnetic coil device according to claim 6, characterized in that, Controlling the timing control module to trigger the pulse width modulation module to output a modulation drive signal with a decreasing duty cycle to the power switching element includes: At the beginning of the second preset time interval, the pulse width modulation module is controlled to output a modulation drive signal with an initial duty cycle decreasing. The duty cycle value of the modulation drive signal decreases linearly with the running time according to a preset slope; At the end of the second preset time interval, the pulse width modulation module is controlled to stop outputting the modulation drive signal, and the duty cycle value of the modulation drive signal is reduced to 0.

10. The control method for a three-stage energy-saving control electromagnetic coil device according to claim 6, characterized in that, The length of the first preset time interval is the travel time of the movable iron core (4) to move to a near-closed position; The time interval of the second preset time interval is the time required for the electromagnetic force of the system to reach a stable state after the movable iron core (4) is closed in place; The modulation frequency of the modulation drive signal output by the pulse width modulation module is higher than the mechanical response frequency of the movable iron core (4).

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