An intelligent load control system and method

Abstract

The application discloses an intelligent load control system and method, which is applied to the technical field of industrial automation. Specifically, a main power supply is connected with a control panel through a leakage protection circuit; a standby power supply is connected with the control panel; the control panel comprises a current measurement circuit, a first relay circuit and a control unit; the control unit is connected with the control end of the first relay circuit and the current measurement circuit respectively; the input end of the first relay circuit is connected with the leakage protection circuit through the current measurement circuit; and the output end of the first relay circuit is connected to a load through an on-off control circuit. Compared with the mode of high-power load control by using a power distribution system in the prior art, the size and wiring amount of the load control circuit are reduced, the actual current value change process at the moment when a fault occurs can be recorded, and the difficulty of load fault analysis is reduced.

Description

Technical Field

[0001] This application relates to the field of industrial automation technology, and in particular to an intelligent load control system and method. Background Technology

[0002] Currently, the automatic control of high-power loads mostly involves a low-voltage controller (PLC or embedded control board, hereinafter referred to as the controller) outputting control signals, which are then used by contactors to control the on / off state of the high-power load (such as heaters, motors, compressors, etc.). To prevent overcurrent faults in the load from causing grid failures or fires, overcurrent protection devices (such as overcurrent circuit breakers, thermal relays, etc.) are generally added before or after the contactor. When an overcurrent occurs in the load, the overcurrent protection device is triggered, and a linkage device usually connects the overcurrent protection device's action signal to the controller's input. After detecting the overcurrent protection signal, the controller issues a control signal according to the pre-set control logic, causing the contactor to turn off and disconnect the power supply to the controlled load.

[0003] However, existing technologies typically employ power distribution systems for the automatic control of high-power loads. These systems consist of numerous components, including controllers, contactors, circuit breakers, thermal relays, and terminal blocks. They are large in size, involve numerous wiring connections, and have high material and labor costs, making automation difficult. The extensive wiring increases the risk of errors, and subsequent testing and inspection are time-consuming. When performing overcurrent fault protection, since the power supply to the controlled load has been cut off, the controller, while able to record the time and location of the fault, cannot record the actual current value changes at the moment the fault occurred. This makes fault analysis significantly more challenging, especially for intermittent faults. Summary of the Invention

[0004] This application provides an intelligent load control system and method to alleviate the aforementioned problems in related technologies.

[0005] The technical solutions provided in this application are as follows:

[0006] On one hand, embodiments of this application provide an intelligent load control system, including: a main power supply, a backup power supply, a leakage protection circuit, a control board, and an on / off control circuit;

[0007] The main power supply is connected to the control board via a leakage current protection circuit, and the main power supply powers the control board. A backup power supply is also connected to the control board, and the backup power supply powers the control board when the main power supply is disconnected. The control board includes a current measurement circuit, a first relay circuit, and a control unit. The control unit is connected to the control terminal of the first relay circuit and the current measurement circuit, respectively. The input terminal of the first relay circuit is connected to the leakage current protection circuit via the current measurement circuit, and the output terminal of the first relay circuit is connected to the load via a switching control circuit. The current measurement circuit is used to detect the load current. The switching control circuit includes a circuit breaker circuit or a contactor circuit, and the switching control circuit is used to disconnect the load from the first relay circuit when the load current meets the first overcurrent action condition. The leakage current protection circuit is used to disconnect the main power supply from the first relay circuit when the load current meets the second overcurrent action condition. The first current threshold in the first overcurrent action condition is less than the second current threshold in the second overcurrent action condition.

[0008] The control unit is used to disconnect the load from the first relay circuit when the load current meets the first overcurrent action condition, and to perform a first-level overcurrent alarm and control the first relay circuit to disconnect when the load current changes to 0; the leakage protection circuit disconnects the main power supply from the first relay circuit when the load current meets the second overcurrent action condition, and to perform a second-level overcurrent alarm and control the first relay circuit to disconnect when the load current changes to 0.

[0009] On the other hand, embodiments of this application provide an intelligent load control method, including:

[0010] The main power supply powers the control board; the backup power supply powers the control board when the main power supply is cut off.

[0011] The control unit acquires the load current detected in real time by the current measurement circuit;

[0012] When the on / off control circuit disconnects the load from the first relay circuit under the condition that the load current meets the first overcurrent action condition, and the magnitude of the load current changes to 0, the control unit will issue a first-level overcurrent alarm and control the first relay circuit to disconnect.

[0013] When the leakage protection circuit disconnects the main power supply from the first relay circuit under the condition that the load current meets the second overcurrent action condition, and the magnitude of the load current changes to 0, the control unit performs a second-level overcurrent alarm and controls the first relay circuit to disconnect; wherein, the first current threshold in the first overcurrent action condition is less than the second current threshold in the second overcurrent action condition.

[0014] The beneficial effects of the embodiments of this application are as follows:

[0015] This invention provides an intelligent load control system. A main power supply is connected to a control board via a leakage current protection circuit, and the main power supply powers the control board. A backup power supply is also connected to the control board, and the backup power supply powers the control board when the main power supply is disconnected. The control board includes a current measurement circuit, a first relay circuit, and a control unit. The control unit is connected to the control terminal of the first relay circuit and the current measurement circuit, respectively. The input terminal of the first relay circuit is connected to the leakage current protection circuit via the current measurement circuit, and the output terminal of the first relay circuit is connected to the load via a switching control circuit. The current measurement circuit detects the load current. The switching control circuit includes a circuit breaker circuit or a contactor circuit, and the switching control circuit is used to activate the load when the load current meets a first overcurrent action condition. The load is disconnected from the first relay circuit; the leakage current protection circuit is used to disconnect the main power supply from the first relay circuit when the load current meets the second overcurrent action condition; wherein, the current threshold in the first overcurrent action condition is less than the current threshold in the second overcurrent action condition; the control unit is used to switch the control circuit on and off to disconnect the load from the first relay circuit when the load current meets the first overcurrent action condition, and to trigger a first-level overcurrent alarm and control the first relay circuit to disconnect when the load current changes to 0; the leakage current protection circuit disconnects the main power supply from the first relay circuit when the load current meets the second overcurrent action condition, and to trigger a second-level overcurrent alarm and control the first relay circuit to disconnect when the load current changes to 0. By using the above technology, by placing the first relay circuit and the control unit and current measurement circuit connected to the first relay circuit on the control board, the size and wiring of the load control circuit are reduced compared to the existing method of using a power distribution system for high-power load control; it also enables real-time monitoring of the load current, and even if the main power supply is cut off, the control board can be powered by a backup power supply to record the actual current value change process at the time of the fault through the control unit, thereby reducing the difficulty of load fault analysis.

[0016] Other features and advantages of this application will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the application. The objectives and other advantages of this application may be realized and obtained by means of the structures particularly pointed out in the written description, claims, and drawings. Attached Figure Description

[0017] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments of this application and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0018] Figure 1 This is a structural example diagram of a power distribution system in the prior art;

[0019] Figure 2 This is a schematic diagram of the structure of the first type of intelligent load control system in the embodiments of this application;

[0020] Figure 3 This is a schematic diagram of the second type of intelligent load control system in the embodiments of this application;

[0021] Figure 4 This is a schematic diagram of the third type of intelligent load control system in the embodiments of this application;

[0022] Figure 5 This is a schematic diagram of the fourth type of intelligent load control system in the embodiments of this application;

[0023] Figure 6 This is a schematic diagram of the fifth type of intelligent load control system in the embodiments of this application;

[0024] Figure 7 This is a flowchart illustrating the intelligent load control method in the embodiments of this application. Detailed Implementation

[0025] To make the objectives, technical solutions, and beneficial effects of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0026] It should be noted that the terms "first," "second," etc., used in this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that the embodiments described herein can be implemented in an order other than that illustrated or described herein. Furthermore, the term "and / or" used in this application describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0027] After introducing the technical terms used in this application, the application scenarios and design concepts of the embodiments of this application will be briefly described below.

[0028] Currently, power distribution systems are commonly used for the automatic control of high-power loads. (See [link]) Figure 1As shown, the power distribution system may include an external three-phase power supply 300, a leakage current protection circuit 200, a controller 1100, a first contactor 800a (also known as KM1), a second contactor 800b (also known as KM2), a first thermal relay 900a, a second thermal relay 900b, a first circuit breaker 1000a, a second circuit breaker 1000b, and terminal blocks, etc. The first contactor 800a, the first thermal relay 900a, and the first circuit breaker 1000a are used to control the on / off of the power supply circuit for the three-phase load M1, while the second contactor 800b, the second thermal relay 900b, and the second circuit breaker 1000b are used to control the on / off of the power supply circuit for the single-phase load R1. When performing overcurrent fault protection, the controller 1100 detects the overcurrent protection signal and outputs a control signal to the contactor of the corresponding load, causing the contactor to turn off and cut off the power supply to the corresponding load. However, the power distribution system is large in size, has many wiring connections, and has relatively high material and labor costs, and is not easily automated. Due to the numerous wiring connections, wiring errors are prone to occur, and subsequent testing and inspection are also time-consuming. When performing overcurrent fault protection, although the controller 1100 can record the time and location of the fault, it cannot record the actual current value change process at the moment the fault occurs. Therefore, the actual fault analysis is quite difficult, especially the analysis of intermittent faults.

[0029] Based on this, the present invention provides an intelligent load control system and method that can alleviate the above-mentioned problems existing in related technologies.

[0030] To facilitate understanding of this embodiment, a detailed description of an intelligent load control system disclosed in this invention will be provided first, see [link to relevant documentation]. Figure 2 As shown, the intelligent load control system includes at least: a main power supply 300, a backup power supply 600, a leakage protection circuit 200, a control board 100, and an on / off control circuit 104.

[0031] The main power supply 300 is connected to the control board 100 via the leakage protection circuit 200, and the main power supply 300 supplies power to the control board 100. The backup power supply 600 is connected to the control board 100, and the backup power supply 600 supplies power to the control board 100 when the main power supply 300 is disconnected. The control board 100 includes a current measurement circuit 102, a first relay circuit 103, and a control unit 101. The control unit 101 is connected to the control terminal of the first relay circuit 103 and the current measurement circuit 102, respectively. The input terminal of the first relay circuit 103 is connected to the leakage protection circuit 200 via the current measurement circuit 102. The output of a relay circuit 103 is connected to the load via a switching control circuit 104; a current measuring circuit 102 is used to detect the load current; the switching control circuit 104 includes a circuit breaker circuit or a contactor circuit, and is used to disconnect the load from the first relay circuit 103 when the load current meets the first overcurrent action condition; a leakage current protection circuit 200 is used to disconnect the main power supply 300 from the first relay circuit 103 when the load current meets the second overcurrent action condition; wherein, the first current threshold in the first overcurrent action condition is less than the second current threshold in the second overcurrent action condition.

[0032] The control unit 101 is used to disconnect the load from the first relay circuit 103 when the load current meets the first overcurrent action condition, and to perform a first-level overcurrent alarm when the load current changes to 0, and to control the first relay circuit 103 to disconnect; the leakage protection circuit 200 disconnects the main power supply 300 from the first relay circuit 103 when the load current meets the second overcurrent action condition, and to perform a second-level overcurrent alarm when the load current changes to 0, and to control the first relay circuit 103 to disconnect.

[0033] In practical applications, the first overcurrent operating condition includes multiple first current thresholds, each corresponding to a load. The magnitude of the first current threshold is determined by the type of load and its operating conditions. The second overcurrent operating condition includes multiple second current thresholds, each corresponding to a load. The magnitude of the second current threshold is determined by the type of load and its operating conditions. There can be multiple loads, and the load type can be a single-phase linear load or a three-phase motor load. Different loads have different first current thresholds, and similarly, different loads have different second current thresholds. The first current threshold for the same load is less than the second current threshold for the same load. The on / off control circuit 104 includes a circuit breaker circuit or a contactor circuit. The number of circuit breakers in the circuit breaker circuit is determined by the number of relays in the first relay circuit 103; similarly, the number of contactors in the contactor circuit is determined by the number of relays in the first relay circuit 103. Replacing the contactor, thermal relay, and circuit breaker in the existing circuit with a circuit breaker circuit and a first relay circuit 103 mounted on the power board, or vice versa, effectively reduces the size and wiring of the load control circuit, and significantly reduces the time required for subsequent testing and inspection. The main power supply 300 can be powered by at least one of DC or AC power; there is no limitation on this. In the event of a main power supply 300 being disconnected, a backup power supply 600 can provide power, allowing the current measurement unit to record the actual current value at all times. This allows for recording the actual current value change process at the moment of fault occurrence during overcurrent fault protection, providing a solid data foundation for fault analysis and greatly reducing the difficulty of analyzing intermittent faults.

[0034] This invention provides an intelligent load control system. A main power supply is connected to a control board via a leakage current protection circuit, and the main power supply powers the control board. A backup power supply is also connected to the control board, and the backup power supply powers the control board when the main power supply is disconnected. The control board includes a current measurement circuit, a first relay circuit, and a control unit. The control unit is connected to the control terminal of the first relay circuit and the current measurement circuit, respectively. The input terminal of the first relay circuit is connected to the leakage current protection circuit via the current measurement circuit, and the output terminal of the first relay circuit is connected to the load via a switching control circuit. The current measurement circuit detects the load current. The switching control circuit includes a circuit breaker circuit or a contactor circuit, and the switching control circuit is used to activate the load when the load current meets a first overcurrent action condition. The load is disconnected from the first relay circuit; the leakage current protection circuit is used to disconnect the main power supply from the first relay circuit when the load current meets the second overcurrent action condition; wherein, the current threshold in the first overcurrent action condition is less than the current threshold in the second overcurrent action condition; the control unit is used to switch the control circuit on and off to disconnect the load from the first relay circuit when the load current meets the first overcurrent action condition, and to trigger a first-level overcurrent alarm and control the first relay circuit to disconnect when the load current changes to 0; the leakage current protection circuit disconnects the main power supply from the first relay circuit when the load current meets the second overcurrent action condition, and to trigger a second-level overcurrent alarm and control the first relay circuit to disconnect when the load current changes to 0. By using the above technology, by placing the first relay circuit and the control unit and current measurement circuit connected to the first relay circuit on the control board, the size and wiring of the load control circuit are reduced compared to the existing method of using a power distribution system for high-power load control; it also enables real-time monitoring of the load current, and even if the main power supply is cut off, the control board can be powered by a backup power supply to record the actual current value change process at the time of the fault through the control unit, thereby reducing the difficulty of load fault analysis.

[0035] As one possible implementation method, see Figure 3As shown, the control board 100 may also be provided with a second relay circuit 105, which is connected to the control unit 101 and the leakage protection circuit 200 respectively. The control unit 101 is also used to: start timing when the load current meets the first overcurrent action condition and the on / off control circuit 104 and the leakage protection circuit 200 are not disconnected, until the timing duration exceeds the preset duration, control the second relay circuit 105 to conduct, so that the leakage protection circuit 200 disconnects the main power supply 300 from the first relay circuit 103, until the load current changes to 0, perform a second-level overcurrent alarm, and control the first relay circuit 103 to disconnect. This operation mode is that when the load current meets the first overcurrent action condition, but the on / off control circuit 104 does not operate, the control unit 101 actively turns on the second relay circuit 105, and then the leakage protection circuit 200 cuts off the connection between the main power supply 300 and the first relay circuit 103, so that when the load current changes to 0, the overcurrent protection and overcurrent alarm are triggered, thereby avoiding damage to the first relay circuit 103 by excessive load current in the case of overcurrent in the load 700, and thus protecting the first relay circuit 103.

[0036] In specific implementation, in the intelligent load 700 control system provided in this embodiment of the invention, the second relay circuit 105 can have various structures to realize its function, for example... Figure 3 As shown, the second relay circuit 105 may include a relay and a first resistor; the first terminal of the relay is connected to the ground wire, the second terminal of the relay is connected to the leakage current protection circuit 200 via the first resistor, and the control terminal of the relay is connected to the control unit 101. It is worth noting that when the main power supply 300 is a three-phase power supply, the first terminal of the relay is connected to the PE line of the three-phase power supply. Thus, by actively activating the relay in the second relay circuit 105 through the control unit 101, the ground wire is connected to the leakage current protection circuit 200, thereby triggering the leakage current protection circuit 200 to operate.

[0037] As one possible implementation, the control unit 101 is also used to: when the load current meets the third overcurrent action condition, to perform an overload alarm and control the first relay circuit 103 to disconnect according to a preset inverse time limit logic; wherein the third current threshold in the third overcurrent action condition is less than the first current threshold in the first overcurrent action condition.

[0038] In practical applications, the third overcurrent action condition includes multiple third current thresholds, each set corresponding to a load 700. These third current thresholds are generally set to the rated current value of the load 700. For each load 700, its third current threshold is less than the first current threshold, and the second current threshold is greater than the first current threshold. Inverse-time logic refers to protection where the operating time of the protection device automatically decreases as the overcurrent increases. Specifically, the characteristic of inverse-time is that the operating time of the protection device varies with the magnitude of the overcurrent; a larger overcurrent results in a shorter operating time, and vice versa. Inverse-time logic also includes standard inverse-time, extreme inverse-time, long inverse-time, and short inverse-time forms, each defined by a curve, with the appropriate inverse-time curve selected based on site requirements. In this operation mode, the control unit 101 performs overload alarm and overload protection according to the magnitude of the load current. This enables the first relay circuit 103 to be disconnected through inverse time protection logic when the load current exceeds the corresponding third current threshold, thus achieving a similar function to that of the thermal relay in the above power distribution system. This avoids the installation and use of the thermal relay and reduces the size and wiring of the load 700 control circuit.

[0039] In one possible implementation, the control unit 101 is also configured to: when the load current meets the second overcurrent action condition, and the on / off control circuit 104 is not disconnected and the leakage protection circuit 200 is disconnected, until the magnitude of the load current changes to 0, trigger a secondary overcurrent alarm and control the first relay circuit 103 to disconnect. This operation mode controls the leakage protection circuit 200 to cut off the main power supply 300 when the load current changes to 0, thereby triggering overcurrent protection and an overcurrent alarm, thus protecting the first relay circuit 103 from excessive load current damage in the event of an overcurrent in the load 700.

[0040] As one possible implementation method, see [link / reference]. Figure 4 As shown, the intelligent load 700 control system also includes a voltage conversion circuit 400. The voltage conversion circuit 400 is connected to the leakage protection circuit 200, the control unit 101, the first relay circuit 103, and the current measurement circuit 102, respectively. It converts the voltage output from the main power supply 300 via the leakage protection circuit 200 into the operating voltage required by the control unit 101 and the current measurement circuit 102, thereby ensuring normal power supply to the control unit 101 and the current measurement circuit 102. The type of voltage conversion circuit 400 is determined by the type of the main power supply 300. When the main power supply 300 is AC, the voltage conversion circuit 400 is an AC-DC converter circuit; when the main power supply 300 is DC, the voltage conversion circuit 400 is a DC-DC converter circuit.

[0041] As one possible implementation method, see [link / reference]. Figure 4 As shown, the intelligent load 700 control system also includes an emergency switching device 500, which is connected to the current measurement circuit 102, the backup power supply 600 and the control board 100 respectively, and is used to switch the power supply mode of the main power supply 300 and / or the backup power supply 600 so as to power the control board 100 through the main power supply 300 and / or the backup power supply 600.

[0042] As one possible implementation, the on / off control circuit 104 can also be a solid-state relay circuit. The solid-state relay circuit consists of multiple solid-state relays controlled by the control unit 101. For each solid-state relay in the solid-state relay circuit, when the current measurement circuit 102 detects that the load current meets the first overcurrent operation condition, the control unit 101 controls the solid-state relay to disconnect the corresponding load from the first relay circuit 103.

[0043] For ease of understanding, the above-mentioned intelligent load control system will be described as an example using a specific application as an example below.

[0044] See Figure 5 As shown, in the control board 100, an MCU is used as the control unit 101. Current transformers H1, H2, H3 and H4 connected in parallel form a current measurement circuit 102. High-power relays K1, K2, K3 and K4 connected in parallel form a first relay circuit 103. Relay K5 and resistor R2 form a second relay circuit 105. A voltage transformer VT is used to form a voltage measurement circuit 106. The MCU is connected to the two ends of H1 (i.e., a and b), the two ends of H2 (i.e., c and d), the two ends of H3 (i.e., e and f), the two ends of H4 (i.e., g and h), K1, K2, K3, K4, K5 and VT respectively. One end of K5 is connected to the PE line of the main power supply, and the other end of K5 is connected to the leakage protection circuit 200 through resistor R2.

[0045] See Figure 5 As shown, outside the control board 100, the parallel circuit breaker (Class I) P1 and three circuit breakers (Class I) P2 form the on / off control circuit 104. The three P2 form the first load circuit breaker circuit 104a, and P1 forms the second load circuit breaker circuit 104b. H1, K1, and P1 are connected in series to form a branch, and P1 is also connected in series with the single-phase load resistor R1. H2, K2, and one P2 are connected in series to form a branch. H3, K3, and one P2 are connected in series to form a branch. H4, K4, and one P2 are connected in series to form a branch. Each of the three P2 is connected in series with the three-phase load M1. The four circuit breakers (Class II) P3 form the leakage protection circuit 200. The L1, L2, L3, and N lines of the main power supply 300 are connected to a, c, e, and g respectively through different P3s.

[0046] See Figure 5 As shown, in addition to the control board 100, an AC / DC switching power supply is used as the voltage conversion circuit 400, and a battery or supercapacitor is used as the backup power supply 600. The emergency switching device 500 is connected to the voltage conversion circuit 400, the backup power supply 600 and the control board 100 respectively.

[0047] The control board 100 may be a PCB board or the like, and the components on the control board 100 may be fixed by means of soldering, snap-fit, or other methods, without any limitation.

[0048] In addition, the control board 100 can be connected to a host computer for communication, thereby facilitating remote monitoring, operation and maintenance management, fault prediction and diagnosis of the load equipment.

[0049] See Figure 5 As shown, when the intelligent load control system is powered on, P3 is turned on to connect the main power supply 300. The control board 100 is also connected to the main power supply 300. The MCU, according to control commands, controls K1, K2, K3, and K4 (with K2, K3, and K4 linked) to engage and conduct. P1 and P2 respectively connect the power supplies to R1 and M1 to ensure their normal operation. The MCU continuously measures and records the load current through H1, H2, H3, and H4. When the load malfunctions and the load current exceeds the specified current, the following situations may occur:

[0050] (1) When the load current meets the first overcurrent action condition, that is, when the magnitude of the load current exceeds the first current threshold corresponding to P1 and / or P2, P1 and / or P2 are disconnected, and P3 is not disconnected; the MCU obtains the load current value measured corresponding to H1 (or H2, H3, H4) and changes from the overcurrent state value to 0, issues an overcurrent alarm (Level I), and shuts down the high-power relay K1 (or K2, K3, K4) corresponding to the load that has experienced overcurrent; this avoids the high-power relay being cut off in the event of an overcurrent fault in the load, thereby protecting the high-power relay.

[0051] (2) When the load current meets the second overcurrent action condition, that is, when the magnitude of the load current exceeds the second current threshold corresponding to P1 and / or P2, due to the different protection action speeds of different circuit breakers (generally, the protection action of P1 and P2 is slower than that of P3), neither P1 nor P2 is disconnected, while P3 is disconnected, cutting off the power supply to the entire intelligent load control system; at this time, since the backup power supply 600 supplies power to the control board 100, the MCU still maintains normal operation and can detect the disconnection of the main power supply 300. The MCU obtains the load current value measured by H1 (or H2, H3, H4) and changes from the overcurrent state value to 0, issues a severe overcurrent alarm (Level II), and shuts down the corresponding high-power relay K1 (or K2, K3, K4); this also avoids the high-power relay being disconnected in the event of an overcurrent fault in the load, thus protecting the high-power relay.

[0052] (3) When the load current meets the second overcurrent action condition, that is, when the magnitude of the load current exceeds the second current threshold corresponding to P1 and / or P2, P1, P2 and P3 are all disconnected, cutting off the power supply of the entire intelligent load control system; at this time, the MCU can issue a serious overcurrent alarm (Level II) and turn off the corresponding high-power relay K1 (or K2, K3 and K4) according to the operation mode of the above situation (2).

[0053] (4) When the load current meets the first overcurrent action condition, that is, the magnitude of the load current exceeds the first current threshold corresponding to P1 and / or P2, and the magnitude of the load current exceeds the first current threshold corresponding to P1 and / or P2 for a certain period of time, and P1, P2, and P3 are not disconnected; at this time, the MCU actively controls K5 to conduct so that R2 and the leakage protection circuit form a leakage circuit, thereby controlling P3 to disconnect through the leakage protection circuit and cutting off the power supply of the entire intelligent load control system; at this time, since the backup power supply 600 supplies power to the control board 100, the MCU still maintains normal operation and can detect the disconnection of the main power supply 300. The MCU obtains the load current value measured by H1 (or H2, H3, H4) and changes from the overcurrent state value to 0, issues a serious overcurrent alarm (Level II), and shuts down the corresponding high-power relay K1 (or K2, K3, K4); this also avoids the high-power relay being cut off in the event of an overcurrent fault in the load, thereby protecting the high-power relay.

[0054] (5) When the load current does not meet the first and second overcurrent operating conditions, but meets the third overcurrent operating condition (i.e., the load current does not exceed the first and second current thresholds corresponding to P1 and P2, but exceeds the rated operating current of R1 and / or M1 (the third current threshold), the MCU will shut down the corresponding high-power relay K1 (or K2, K3, K4) according to the preset inverse-time protection logic (i.e., the larger the overcurrent, the faster the relay is cut off) and issue an overload alarm. In this way, the function of the thermal relay can be realized by the MCU executing the inverse-time protection logic, thereby saving the installation and use of the thermal relay.

[0055] Furthermore, in practical applications, the relay circuit in the aforementioned on / off control circuit 104 can be replaced with a contactor circuit. Based on this, the control unit 101 can also be used to: when the load current exceeds a preset third current threshold, control the first relay circuit 103 to disconnect according to a preset inverse-time protection logic. This operation disconnects the first relay circuit 103 through inverse-time protection logic when an overcurrent occurs in the load 700. Since this operation function is similar to that of the thermal relay in the aforementioned power distribution system, the installation and use of the thermal relay can be avoided, thereby reducing the size and wiring of the load control circuit. For example... Figure 6 As shown, the above Figure 5 The circuit breaker (Class I) P1 and three circuit breakers (Class I) P2 connected in parallel are replaced with contactors KM3 and three contactors KM4 connected in parallel, respectively. Thus, KM3 and three KM4 form a load contactor circuit. The three KM4 form the first load contactor circuit 800d, and KM3 forms the second load contactor circuit 800c. H1, K1, and KM3 are connected in series to form a branch. KM3 is also connected in series with the single-phase load resistor R1. H2, K2, and one KM4 are connected in series to form a branch. H3, K3, and one KM4 are connected in series to form a branch. H4, K4, and one KM4 are connected in series to form a branch. Each of the three KM4 is connected in series with the three-phase load M1. When the intelligent load control system is powered on, P3 is turned on to connect the external three-phase power supply 300, and the control board 100 is connected to the main power supply 300. The MCU, according to control commands, controls K1, K2, K3, and K4 (with K2, K3, and K4 linked) to engage and conduct. KM3 and KM4 respectively connect the power supplies to R1 and M1 to ensure their normal operation. The MCU continuously measures and records the load current through H1, H2, H3, and H4. When the load current meets the third overcurrent condition, i.e., the load current exceeds the rated operating current (third current threshold) of R1 and / or M1, the MCU shuts off the corresponding high-power relay K1 (or K2, K3, and K4) according to the preset inverse-time protection logic. This allows the MCU to execute the inverse-time protection logic to achieve the function of a thermal relay, thus saving on the installation and use of thermal relays.

[0056] In the aforementioned intelligent load control system, high-power relays mounted on the control board replace the contactors in the power distribution system of related technologies. The inverse-time protection logic of the MCU on the control board replaces the thermal relays in the power distribution system of related technologies. Current transformers mounted on the control board monitor overcurrent. Together with external circuit breakers or contactors, leakage protection circuits, main power supply, and backup power supply, the system achieves load control and protection. Therefore, the aforementioned intelligent load control system can realize most of the functions of the power distribution system composed of controllers, contactors, circuit breakers, and thermal relays in related technologies through the control board. This achieves miniaturization, universality, and standardization of load control and protection. Furthermore, the aforementioned intelligent load control system has a small number of wiring connections, which is convenient for mass production and facilitates real-time monitoring of the operating status of load equipment and fault analysis of load equipment.

[0057] This application provides an intelligent load control method, see below. Figure 7 As shown, the general flow of the intelligent load control method provided in this application embodiment is as follows:

[0058] Step 701: The main power supply powers the control board; the backup power supply powers the control board when the main power supply is cut off.

[0059] Step 702: The control unit acquires the load current detected in real time by the current measurement circuit.

[0060] Step 703: When the on / off control circuit disconnects the load from the first relay circuit under the condition that the load current meets the first overcurrent action condition, and the magnitude of the load current changes to 0, the control unit performs a first-level overcurrent alarm and controls the first relay circuit to disconnect.

[0061] Step 704: When the leakage protection circuit disconnects the main power supply from the first relay circuit under the condition that the load current meets the second overcurrent action condition, and the magnitude of the load current changes to 0, the control unit performs a second-level overcurrent alarm and controls the first relay circuit to disconnect; wherein, the first current threshold in the first overcurrent action condition is less than the second current threshold in the second overcurrent action condition.

[0062] As one possible implementation, the intelligent load control method further includes:

[0063] The control unit starts timing when the load current meets the first overcurrent action condition and the on / off control circuit and leakage protection circuit are not disconnected. When the timing duration exceeds the preset duration, the control unit controls the second relay circuit to conduct, so that the leakage protection circuit disconnects the main power supply from the first relay circuit. When the load current changes to 0, a second-level overcurrent alarm is triggered, and the control unit controls the first relay circuit to disconnect.

[0064] As one possible implementation, the intelligent load control method further includes:

[0065] When the load current meets the third overcurrent action condition, the control unit will issue an overload alarm and control the first relay circuit to disconnect according to the preset inverse time protection logic; wherein, the current threshold in the third overcurrent action condition is less than the current threshold in the first overcurrent action condition.

[0066] As one possible implementation, the intelligent load control method further includes:

[0067] When the load current meets the second overcurrent action condition, and the on / off control circuit is not disconnected and the leakage protection circuit is disconnected, the control unit will issue a second-level overcurrent alarm and control the first relay circuit to disconnect when the load current changes to 0.

[0068] The intelligent load control method provided in this embodiment of the invention has the same implementation principle and technical effect as the aforementioned intelligent load control system embodiment. For the sake of brevity, any parts not mentioned in the method embodiment can be referred to the corresponding content in the aforementioned system embodiment.

[0069] It should be noted that although several units or sub-units of the device have been mentioned in the detailed description above, this division is merely exemplary and not mandatory. In fact, according to embodiments of this application, the features and functions of two or more units described above can be embodied in one unit. Conversely, the features and functions of one unit described above can be further divided and embodied by multiple units.

[0070] Furthermore, although the operations of the method of this application are described in a specific order in the accompanying drawings, this does not require or imply that these operations must be performed in that specific order, or that all the operations shown must be performed to achieve the desired result. Additionally or alternatively, certain steps may be omitted, multiple steps may be combined into one step, and / or one step may be broken down into multiple steps.

[0071] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0072] Obviously, those skilled in the art can make various modifications and variations to the embodiments of this application without departing from the spirit and scope of the embodiments of this application. Therefore, if these modifications and variations to the embodiments of this application fall within the scope of the claims of this application and their equivalents, this application also intends to include these modifications and variations.

Claims

1. An intelligent load control system, characterized in that, include: Main power supply, backup power supply, leakage protection circuit, control board, and on / off control circuit; The main power supply is connected to the control board via the leakage protection circuit, and the main power supply is used to power the control board. The backup power supply is connected to the control board, and the backup power supply is used to power the control board when the main power supply is cut off. The control board includes a current measurement circuit, a first relay circuit, and a control unit. The control unit is connected to the control terminal of the first relay circuit and the current measurement circuit, respectively. The input terminal of the first relay circuit is connected to the leakage protection circuit via the current measurement circuit, and the output terminal of the first relay circuit is connected to the load via the on / off control circuit. The current measurement circuit is used to detect the load current. The on / off control circuit includes a circuit breaker circuit or a contactor circuit. The on / off control circuit is used to disconnect the load from the first relay circuit when the load current meets a first overcurrent action condition. The leakage protection circuit is used to disconnect the main power supply from the first relay circuit when the load current meets a second overcurrent action condition. Wherein, the first current threshold in the first overcurrent action condition is less than the second current threshold in the second overcurrent action condition. The control unit is used by the on / off control circuit to disconnect the load from the first relay circuit when the load current meets the first overcurrent action condition, and to perform a first-level overcurrent alarm when the load current changes to 0, and to control the first relay circuit to disconnect; the leakage protection circuit disconnects the main power supply from the first relay circuit when the load current meets the second overcurrent action condition, and to perform a second-level overcurrent alarm when the load current changes to 0, and to control the first relay circuit to disconnect.

2. The intelligent load control system according to claim 1, characterized in that, The control board is also equipped with a second relay circuit, which is connected to the control unit and the leakage protection circuit respectively. The control unit is also used to: start timing when the load current meets the first overcurrent action condition and the on / off control circuit and the leakage protection circuit are not disconnected, until the timing duration exceeds the preset duration, control the second relay circuit to conduct, so that the leakage protection circuit disconnects the main power supply from the first relay circuit, until the load current changes to 0, perform a second-level overcurrent alarm, and control the first relay circuit to disconnect.

3. The intelligent load control system according to claim 2, characterized in that, The second relay circuit includes a relay and a first resistor; The first terminal of the relay is connected to the ground wire, the second terminal of the relay is connected to the leakage protection circuit via the first resistor, and the control terminal of the relay is connected to the control unit.

4. The intelligent load control system according to claim 1, characterized in that, The control unit is further configured to: when the load current meets the third overcurrent action condition, perform an overload alarm and control the first relay circuit to disconnect according to a preset inverse time protection logic; wherein the third current threshold in the third overcurrent action condition is less than the first current threshold in the first overcurrent action condition.

5. The intelligent load control system according to claim 1, characterized in that, The control unit is also configured to: when the load current meets the second overcurrent action condition, and the on / off control circuit is not disconnected and the leakage protection circuit is disconnected, until the magnitude of the load current changes to 0, perform a secondary overcurrent alarm and control the first relay circuit to disconnect.

6. The intelligent load control system according to any one of claims 1-5, characterized in that, It also includes a voltage conversion circuit; the voltage conversion circuit is connected to the leakage protection circuit, the control unit, the first relay circuit and the current measurement circuit respectively, and is used to convert the voltage output by the main power supply through the leakage protection circuit into the operating voltage required by the control unit and the current measurement circuit respectively, so as to realize the normal power supply of the control unit and the current measurement circuit.

7. The intelligent load control system according to claim 6, characterized in that, The system also includes an emergency switching device, which is connected to the current measurement circuit, the backup power supply and the control board respectively, and is used to switch the power supply mode of the main power supply and / or the backup power supply so as to power the control board through the main power supply and / or the backup power supply.

8. A smart load control method, characterized in that, The method is applied to the intelligent load control system according to any one of claims 1-6; the method includes: The main power supply powers the control board; the backup power supply powers the control board when the main power supply is cut off. The control unit acquires the load current detected in real time by the current measurement circuit; When the on / off control circuit disconnects the load from the first relay circuit under the condition that the load current meets the first overcurrent action condition, and when the magnitude of the load current changes to 0, the control unit performs a first-level overcurrent alarm and controls the first relay circuit to disconnect. The control unit disconnects the main power supply from the first relay circuit when the load current meets the second overcurrent action condition, and when the magnitude of the load current changes to 0, it performs a second-level overcurrent alarm and controls the first relay circuit to disconnect; wherein, the first current threshold in the first overcurrent action condition is less than the second current threshold in the second overcurrent action condition.

9. The intelligent load control method according to claim 8, characterized in that, The method further includes: The control unit starts timing when the load current meets the first overcurrent action condition and the on / off control circuit and the leakage protection circuit are not disconnected. When the timing duration exceeds the preset duration, the control unit controls the second relay circuit to conduct, so that the leakage protection circuit disconnects the main power supply from the first relay circuit. When the load current changes to 0, a second-level overcurrent alarm is triggered, and the first relay circuit is controlled to disconnect.

10. The intelligent load control method according to claim 8, characterized in that, The method further includes: When the load current meets the third overcurrent action condition, the control unit performs an overload alarm and controls the first relay circuit to disconnect according to the preset inverse time protection logic; wherein, the current threshold in the third overcurrent action condition is less than the current threshold in the first overcurrent action condition.

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