Low-power-consumption energy-saving control method and system for intelligent solid-state contactor of subway train

Abstract

The invention discloses a low-power-consumption energy-saving control method and system for an intelligent solid-state contactor of a subway train, and the method comprises the steps: collecting load current data and a train working condition instruction in real time, analyzing the working condition characteristics, and judging three operation modes: full-function working, low-load energy saving and no-load micro-power consumption in combination with preset no-load and low-load thresholds; differential power consumption adjustment strategies are executed on core modules such as a solid-state power unit and a control unit of the solid-state contactor according to different modes; and meanwhile, quick switching of the energy-saving mode and forced fault quit protection are realized, the full-function working mode is quickly switched back when the load is recovered, and the energy-saving mode is immediately quitted and full-function fault protection is started when a fault occurs. The intelligent solid-state contactor solves the problem that a traditional solid-state contactor is high in invalid power consumption under the low-load / no-load working condition of a subway train, dynamic adaptation of the power consumption of the contactor is achieved, the no-load power consumption is reduced by 60% or above, and the intelligent solid-state contactor can be widely adapted to all high-power power supply loops of the subway train.

Description

A Low-Power Energy-Saving Control Method and System for Intelligent Solid-State Contactors in Metro Trains Technical Field

[0001] This invention relates to the field of electrical control technology for subway trains, and in particular to a low-power energy-saving control method and system for intelligent solid-state contactors in subway trains. Background Technology

[0002] Contactors are core control devices in the high-power power supply circuits of subway trains, including lighting, braking, traction, and air conditioning. Intelligent solid-state contactors, due to their advantages such as the absence of mechanical contacts, high reliability, and superior intelligence, have gradually replaced traditional mechanical contactors as the mainstream choice for subway trains. However, existing intelligent solid-state contactors in subway trains generally adopt a continuous operation mode with full functionality under all operating conditions, without power consumption optimization design tailored to the specific operating conditions of subway trains. Subway trains frequently experience periods of stoppage and standby, nighttime maintenance, and low-load operation. Under these conditions, the power supply circuit load rate is extremely low or even unloaded, while the solid-state power unit, control unit, detection unit, and heat dissipation unit of the solid-state contactor remain at full load, resulting in a large amount of ineffective power consumption by the contactor itself. This does not meet the industry's development needs for energy conservation and consumption reduction in subway onboard equipment.

[0003] Existing low-power solid-state switch solutions in the industrial sector are mostly simple "standby / operation" modes. They lack customized designs to address the characteristics of subway trains, such as frequent changes in operating conditions, large load fluctuations, and limited onboard power resources. These solutions cannot achieve dynamic and precise power consumption adjustment and lack a rapid energy-saving mode exit mechanism, easily leading to contactor response lag when the load recovers, affecting the stability of subway train power supply. Furthermore, some low-power solutions require the addition of dedicated energy-saving devices, resulting in high retrofit costs and incompatibility with existing subway intelligent solid-state contactors, hindering industrialization and the upgrading of existing equipment.

[0004] In summary, there is an urgent need for a low-power energy-saving control method and system for intelligent solid-state contactors of subway trains that is adapted to the operating conditions of subway trains, takes into account energy saving and power supply stability, and has low retrofit costs, in order to overcome the shortcomings of existing technologies. Summary of the Invention

[0005] The purpose of this invention is to provide a low-power energy-saving control method and system for intelligent solid-state contactors in subway trains, which solves the problems of high ineffective power consumption, poor adaptability of energy-saving mode to subway operating conditions, and slow mode switching response of existing intelligent solid-state contactors under low load / no-load conditions of subway trains. It realizes dynamic and fine adjustment of contactor power consumption, and maximizes the reduction of ineffective power consumption of contactors while ensuring the stability of power supply and fault protection of subway trains.

[0006] To achieve the above objectives, the present invention provides the following technical solution: According to one aspect of the present invention, a low-power energy-saving control method for a smart solid-state contactor in a subway train is provided, comprising the following steps: S1: Real-time acquisition of load current data at the output terminal of the solid-state contactor, receiving operating condition commands, and extracting operating condition characteristics by parsing the load current data and operating condition commands; S2: By comparing the load current data with preset no-load thresholds and low-load thresholds, and based on the comparison results combined with the operating condition commands, determining whether the contactor enters a full-function working mode, a low-load energy-saving mode, or a no-load low-power mode; S3: According to the determined operating mode, implementing differentiated power consumption adjustment strategies for the solid-state power unit, control unit, detection unit, and heat dissipation unit of the solid-state contactor; S4: When load recovery is detected or a load recovery command from the train's upper-level control is received, the control unit drives the contactor to switch from the low-load energy-saving mode or the no-load low-power mode to the full-function working mode; S5: When a fault signal is detected in the low-load energy-saving mode or the no-load low-power mode, immediately exiting the current mode and activating full-function fault protection.

[0007] According to one embodiment of the present invention, in step S1, the operating condition command comes from the train's upper control system and includes at least one of normal driving, parking standby, night maintenance, traction start, air conditioning full load, and lighting half load.

[0008] According to an embodiment of the present invention, in step S2, the no-load threshold is 5% of the rated current of the solid-state contactor, and the low-load threshold is 30% of the rated current of the solid-state contactor; and the no-load threshold and the low-load threshold are adaptively adjusted according to the rated current of different power supply circuits for lighting, braking, traction and air conditioning of the subway train.

[0009] According to an embodiment of the present invention, in step S2, the rules for determining the operating mode specifically include: if the load current is greater than or equal to the low load threshold, and / or the operating condition command is a normal power supply command, it is determined to be a full-function operating mode; if the no-load threshold is less than the load current and less than the low load threshold, and / or the operating condition command is a low load power supply command, it is determined to be a low load energy-saving mode; if the load current is less than or equal to the no-load threshold, and / or the operating condition command is a no-load standby command, it is determined to be a no-load low power consumption mode; the mode determination period is 500ms.

[0010] According to an embodiment of the present invention, in step S3, the power consumption adjustment strategy of the full-function working mode is as follows: the solid-state power unit adopts a conventional conduction strategy, the control unit operates at the highest operating frequency, the detection unit collects data in real time across all channels, the heat dissipation unit automatically adjusts the heat dissipation power according to the power tube temperature, and the communication unit transmits data at full rate.

[0011] According to an embodiment of the present invention, in step S3, the power consumption adjustment strategy of the low load power saving mode includes: the control unit reduces the frequency to the medium main frequency of 50~80MHz and shuts down the non-core computing modules; the solid-state power unit uses the minimum conduction loss modulation algorithm to adjust the conduction angle of the semiconductor switching device; the detection unit shuts down the non-core detection channels and only retains the acquisition of voltage, current and core temperature; the heat dissipation unit appropriately reduces the heat dissipation power according to the temperature of the power tube.

[0012] According to an embodiment of the present invention, in step S3, the power consumption adjustment strategy of the idle low-power mode includes: the solid-state power unit cuts off the main power supply circuit and enters a low-power standby state, retaining only the core wake-up module; the control unit reduces the main frequency to the lowest ≤20MHz and enters the energy-saving operation mode, retaining only the working condition identification and command receiving functions; the detection unit retains only the idle fault detection channel; the heat dissipation unit completely stops active heat dissipation; the communication unit enters a low-speed sleep communication mode, receiving only commands and fault trigger signals.

[0013] According to one embodiment of the present invention, in step S4, a dual switching mechanism of hardware triggering and software triggering is adopted. Hardware triggering is triggered when the load current is detected to increase sharply within 10ms and exceed the low load threshold, and software triggering is triggered when the train upper load recovery command is received.

[0014] According to an embodiment of the present invention, in steps S2 to S5, a mode switching anti-shake mechanism is set, and the interval between two adjacent operation mode switching is not less than 3s; in step S5, the fault signal includes at least one of short circuit, overvoltage, reverse connection, and overtemperature fault signals, and the full-function fault protection is a dual fault protection mechanism combining hardware and software.

[0015] On the other hand, the present invention also provides a low-power energy-saving control system for intelligent solid-state contactors in subway trains, comprising: a working condition acquisition module, a mode determination module, a power consumption adjustment module, a mode switching module, and a fault protection module; the working condition acquisition module is used to acquire load current data at the output terminal of the solid-state contactor in real time, receive working condition commands from the train's upper-level system, and parse and extract working condition characteristics from the data and commands; the mode determination module has built-in preset no-load threshold and low-load threshold, used to compare the load current data with the threshold and determine the operating mode of the contactor in combination with the working condition characteristics; the power consumption adjustment module is electrically connected to the solid-state power unit, control unit, detection unit, and heat dissipation unit of the solid-state contactor, and is used to send differentiated power consumption adjustment commands to each module according to the operating mode; the mode switching module is used to detect the load recovery status, receive load recovery commands, and drive the contactor to switch from energy-saving mode to full-function operating mode; the energy-saving mode includes low-load energy-saving mode or no-load low-power mode; the fault protection module is used to detect fault signals in the energy-saving mode, drive the contactor to exit the current energy-saving mode and activate full-function fault protection.

[0016] The present invention provides a low-power energy-saving control method and system for intelligent solid-state contactors of subway trains. Compared with the prior art, the beneficial effects of the present invention are as follows: (1) It fully adapts to the subway operating conditions and greatly reduces ineffective power consumption. In view of the alternating operating conditions of subway trains, such as parking standby, low-load driving and normal driving, a three-level operating mode is designed and a differentiated power consumption adjustment strategy is implemented to realize the dynamic adaptation of contactor power consumption. The power consumption is reduced by more than 60% under no-load conditions and by 30%~50% under low-load conditions, which effectively reduces the ineffective consumption of subway on-board power supply resources and meets the energy-saving and consumption-reducing development needs of the subway industry.

[0017] (2) Quickly switch modes to ensure power supply stability; by adopting a dual switching mechanism of hardware triggering and software triggering, the response time from energy-saving mode to full-function working mode is ≤10ms, which solves the problem of slow switching and delayed response of traditional energy-saving mode, fully adapts to the characteristics of frequent alternation of subway train working conditions, and ensures continuous and unrestricted power supply when the load is restored.

[0018] (3) Prioritize fault protection to improve operational safety; by setting a fault forced exit mechanism, when any fault signal is detected in the energy-saving mode, the energy-saving mode will be immediately exited and the dual full-function fault protection of hardware and software will be started to ensure that the fault is handled quickly and effectively, avoid the failure of fault protection caused by the energy-saving mode, and take into account both energy saving and operational safety.

[0019] (4) No new hardware is required and the transformation cost is low. This invention is based on the existing hardware architecture of the intelligent solid contactor of subway trains. The entire process of energy-saving control is completed only through software programming and algorithm optimization. No new special energy-saving devices are required, the transformation cost is low, and it can be directly compatible with the existing solid contactor, which is convenient for industrial promotion and upgrading of existing subway equipment.

[0020] (5) High versatility and adaptability to multiple circuit requirements; the no-load threshold and low-load threshold can be adaptively adjusted according to the rated current of different high-power power supply circuits such as lighting, braking, traction, and air conditioning of subway trains. It is an intelligent solid-state contactor that is compatible with all subway power supply circuits, with a wide range of applications and strong practicality. Improve equipment reliability through anti-shake design: The anti-shake mechanism for mode switching is set to avoid frequent start-stop of modules caused by frequent fluctuations in operating conditions, reduce device wear, extend the service life of the contactor, and further improve the reliability and stability of equipment operation. Attached Figure Description

[0021] The accompanying drawings, which are included to provide a further understanding of the invention and constitute a part of this invention, illustrate exemplary embodiments of the invention and, together with their descriptions, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings: Figure 1 is a flowchart of a low-power energy-saving control method for a smart solid-state contactor in a subway train according to an embodiment of the present invention; Figure 2 is a schematic diagram of a low-power energy-saving control system for a smart solid-state contactor in a subway train according to an embodiment of the present invention; Figure 3 is a hardware principle block diagram of a smart solid-state contactor in a subway train according to an embodiment of the present invention. Detailed Implementation

[0022] To facilitate a clear description of the technical solutions in the embodiments of the present invention, the terms "first" and "second" are used to distinguish identical or similar items with essentially the same function and effect. For example, the first threshold and the second threshold are merely used to distinguish different thresholds and do not limit their order. Those skilled in the art will understand that the terms "first" and "second" do not limit the quantity or execution order, and that the terms "first" and "second" are not necessarily different.

[0023] It should be noted that in this invention, the terms "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in this invention should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0024] In this invention, "at least one" refers to one or more, and "more than one" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one" or similar expressions refer to any combination of these items, including any combination of singular or plural items. For example, "at least one of a, b, or c" can represent: a, b, c, a combination of a and b, a combination of a and c, a combination of b and c, or a, b, and c, where a, b, and c can be single or multiple.

[0025] Figure 1 shows a flowchart of a low-power energy-saving control method for a smart solid-state contactor in a subway train. The method includes the following steps: S101: Real-time acquisition of load current data at the output of the solid-state contactor, receiving operating condition commands, and extracting operating condition features by parsing the load current data and operating condition commands; For the high-frequency vibration interference of 5-200Hz in subway trains, an adaptive Kalman filter algorithm is used to filter the load current data. By estimating the noise covariance of the current signal in real time, the filter gain is dynamically adjusted. Compared with conventional low-pass filtering, it can eliminate high-frequency noise caused by vibration while preserving the characteristics of current abrupt changes (such as load start-up impact); the state equation dimension of the filtering algorithm is 2 (current amplitude, current change rate), the initial value of the noise variance of the observation equation is set to 0.01, and the adaptive adjustment step size is 0.005 to ensure real-time performance and filtering effect at a 10Hz acquisition frequency. The acquired load current data is processed by an adaptive Kalman filter algorithm, and the noise covariance of the algorithm is adaptively adjusted in real time to adapt to the vibration interference of 5-200Hz in subway trains.

[0026] The operating condition commands come from the train's upper control system and cover typical operating conditions of subway trains, such as normal driving, parking and standby, night maintenance, traction start, air conditioning at full load, and lighting at half load. At the same time, the collected load current data is processed by software filtering to eliminate signal interference caused by subway vibration and ensure data accuracy.

[0027] S102: By comparing the load current data with the preset no-load threshold and low-load threshold, and based on the comparison results combined with the operating condition command, the contactor is determined to enter the full-function working mode, low-load energy-saving mode, or no-load low-power mode. The preset no-load threshold is 5% of the rated current of the solid-state contactor, and the low-load threshold is 30% of the rated current. Both thresholds can be adaptively adjusted according to the rated current of different power supply circuits of the subway train. The mode determination period is set to 500ms to balance the timeliness and stability of the determination. The determination rule is based on both the load current range and the type of operating condition command to ensure that the operating mode matches the actual operating condition.

[0028] S103: Based on the determined operating mode, implement differentiated power consumption adjustment strategies for the solid-state power unit, control unit, detection unit, and heat dissipation unit of the solid-state contactor respectively; the power consumption adjustment strategy of the full-function operating mode is as follows: the solid-state power unit adopts a conventional conduction strategy, the control unit operates at the highest operating frequency, the detection unit collects data in real time across all channels, the heat dissipation unit automatically adjusts the heat dissipation power according to the power tube temperature, and the communication unit transmits data at full rate.

[0029] The power consumption adjustment strategy of the low-load energy-saving mode includes: the control unit reduces the frequency to the medium main frequency of 50~80MHz and shuts down the non-core computing modules; the solid-state power unit uses the minimum conduction loss modulation algorithm to adjust the conduction angle of the semiconductor switching device; the detection unit shuts down the non-core detection channels and only retains the acquisition of voltage, current and core temperature; the heat dissipation unit appropriately reduces the heat dissipation power according to the temperature of the power tube.

[0030] The power consumption adjustment strategy of the idle low-power mode includes: the solid-state power unit cuts off the main power supply circuit and enters a low-power standby state, retaining only the core wake-up module; the control unit reduces the main frequency to the minimum ≤20MHz and enters the energy-saving operation mode, retaining only the working condition identification and command receiving functions; the detection unit retains only the idle fault detection channel; the heat dissipation unit completely stops active heat dissipation; and the communication unit enters a low-speed sleep communication mode, receiving only commands and fault trigger signals.

[0031] The minimum conduction loss modulation algorithm includes an inductive load freewheeling compensation stage, dynamically adjusting the turn-off time of semiconductor switching devices based on the load current freewheeling time. For the inductive load characteristics of subway power supply circuits (e.g., the inductance of air conditioning compressors and traction motors is 10-50mH), a freewheeling compensation stage is added to the conventional minimum conduction loss modulation algorithm. By detecting the load current freewheeling time, the conduction angle and turn-off time of the switching devices are dynamically adjusted to avoid additional losses during the freewheeling phase. The minimum conduction loss modulation algorithm process includes: ① collecting load current and supply voltage data; ② calculating load inductance and resistance parameters; ③ solving for the optimal conduction angle based on the minimum loss model; ④ dynamically adjusting the turn-off time in conjunction with the freewheeling time; ⑤ outputting a modulation signal to control the solid-state power unit. Compared to the conventional modulation algorithm, this improved algorithm can reduce conduction losses by more than 25% under low load conditions. At a low load current of 5A, the power transistor loss is reduced from 1.2W to 0.9W.

[0032] Differentiated power consumption adjustment strategies are designed for the three operating modes. While ensuring the core functions of the corresponding operating conditions, targeted power consumption optimization is carried out for each module to maximize the reduction of ineffective power consumption.

[0033] S104: When load recovery is detected or a load recovery command is received from the train's upper control unit, the control unit drives the contactor to switch from low-load energy-saving mode or no-load low-power mode to full-function working mode; a dual switching mechanism of hardware triggering and software triggering is adopted to ensure that the contactor can quickly switch to full-function working mode within 10ms when the load is restored, with no power supply response lag; S105: When a fault signal is detected in low-load energy-saving mode or no-load low-power mode, the current mode is immediately exited and full-function fault protection is activated.

[0034] By setting a mode switching anti-jitter mechanism, the interval between two adjacent mode switches is no less than 3 seconds, avoiding repeated module start-ups and shutdowns caused by frequent fluctuations in operating conditions. Fault signals include common fault types such as short circuit, overvoltage, reverse connection, and overtemperature. The full-function fault protection adopts a dual protection mechanism of hardware and software to ensure that faults can be handled quickly and effectively, preventing the fault from escalating.

[0035] Figure 2 shows a schematic diagram of a low-power energy-saving control system for a smart solid-state contactor in a subway train. The system includes: a working condition acquisition module, a mode determination module, a power consumption adjustment module, a mode switching module, and a fault protection module.

[0036] The operating condition acquisition module is used to acquire load current data at the output terminal of the solid-state contactor in real time, receive operating condition commands from the train's upper control, and analyze the data and commands to extract operating condition characteristics. The mode determination module has built-in preset no-load threshold and low-load threshold, which are used to compare the load current data with the threshold and determine the operating mode of the contactor in combination with the operating condition characteristics. The power consumption adjustment module is electrically connected to the solid-state power unit, control unit, detection unit, and heat dissipation unit of the solid-state contactor, and is used to send differentiated power consumption adjustment commands to each module according to the operating mode. The mode switching module is used to detect the load recovery status, receive load recovery commands, and drive the contactor to switch from energy-saving mode to full-function operating mode. The energy-saving mode includes low-load energy-saving mode or no-load low-power mode. The fault protection module is used to detect fault signals in energy-saving mode, drive the contactor to exit the current energy-saving mode and activate full-function fault protection.

[0037] As shown in Figure 3, the hardware architecture of the intelligent solid-state contactor for subway trains includes: power input port VIN, load output port VOUT, fuse, shunt resistor, upper and lower bridge arm semiconductor power switching devices, voltage detection module, current detection module, electrical isolation device isolate, ARM architecture microcontroller MCU, and hardware protection module.

[0038] The power input port VIN is connected in series with a fuse and a shunt resistor, and then connected to the input terminals of the upper and lower bridge arm semiconductor power switching devices. The output terminals of the upper and lower bridge arm semiconductor power switching devices are connected to the load output port VOUT, forming a complete power switching path. This replaces traditional mechanical contacts to achieve arc-free and wear-free switching control, and supports a maximum rated current of 20A DC and 25A AC.

[0039] The voltage detection module collects the input voltage at the VIN terminal and the output voltage at the VOUT terminal, and transmits the voltage signals to the MCU. The current detection module collects the load current signal through the shunt resistor Shunt, and transmits the current signal to the MCU and the Hardware module, respectively, for fault judgment and operating condition identification such as overcurrent, short circuit, and overload.

[0040] The MCU is the core control unit, which is electrically connected to the hardware module through an isolation device to achieve electrical isolation between the control side and the power side, avoiding high voltage interference. The MCU integrates two-stage overload protection, over-temperature protection, two-stage overvoltage protection, programmable overload value configuration, communication control, log data uploading, driver self-test, and LED status display functions to realize intelligent control, software protection, and data management.

[0041] The Hardware module is an independent hardware protection unit that is electrically connected to the upper and lower bridge arm semiconductor power switching devices and the current detection module. The Hardware module integrates hardware overvoltage protection, hardware overload protection, hardware short circuit protection, hardware reverse connection protection, hardware overvoltage blocking, and hardware short circuit blocking functions. The fault response time is ≤40μs, and it can independently complete the rapid blocking and protection actions for emergency faults when the MCU fails.

[0042] Example 1: This example uses a dedicated intelligent solid-state contactor (AC rated current 25A) for the air conditioning control panel of a subway train as an example to describe in detail the low-power energy-saving control method and system of the present invention. The hardware architecture of the contactor includes a control unit with an ARMMCU as the core, a Hall effect detection unit, a solid-state power unit composed of semiconductor switching devices, a three-level temperature control heat dissipation unit, and a CAN / ETH dual-network communication unit. The low-power energy-saving control system of the present invention is integrated into the above hardware architecture.

[0043] Step 1: Parameter Preset and Operating Condition Acquisition; The no-load threshold is set to 5% of the rated current, which is the optimal value determined by 1000 hours of real-vehicle testing based on the leakage current characteristics of the air conditioning, lighting, and other circuits of the subway train under no-load conditions. This effectively avoids mode misjudgment caused by leakage current. The low-load threshold is set to 30% of the rated current, matching the load rate range of the power supply circuit when the subway train is running under low load, balancing energy saving and power supply stability. For this 25A AC solid-state contactor, the preset no-load threshold = 1.25A (25A × 5%), and the low-load threshold = 7.5A (25A × 30%); the mode determination cycle is 500ms, the mode switching anti-jitter interval is 3s, and the energy-saving mode switching response time is ≤10ms.

[0044] The operating condition acquisition module collects load current data of the air conditioning circuit at a frequency of 10Hz through the detection unit, and eliminates subway vibration interference through software filtering; at the same time, it receives operating condition commands sent by the train air conditioning controller through the communication unit. In this embodiment, the operating condition commands include air conditioning full load, air conditioning half load, and air conditioning off, and the module analyzes the load current data and operating condition commands to extract operating condition features.

[0045] Step 2: Operating Mode Determination; The mode determination module determines the mode based on a 500ms cycle, comparing the load current data with the threshold and the operating condition command: When the air conditioner is running at full load, the load current = 20A ≥ 7.5A, and the operating condition command is "Air conditioner full load", it is determined to be a full-function operating mode; When the air conditioner is running at half load, the load current = 5A, satisfying 1.25A < 5A < 7.5A, and the operating condition command is "Air conditioner half load", it is determined to be a low-load energy-saving mode; When the subway is stopped and in standby mode, the air conditioner is off, the load current = 0A ≤ 1.25A, and the operating condition command is "Air conditioner off", it is determined to be an no-load low-power mode.

[0046] If the subway train stops briefly for 1 second and then starts immediately, the load current will fluctuate repeatedly between 0A and 20A. Since the mode switching anti-shake interval is 3 seconds, the contactor will maintain full-function operation mode to avoid repeated mode switching.

[0047] Step 3: Differentiated power consumption adjustment; The power consumption adjustment module sends power consumption adjustment instructions to the solid-state power unit, control unit, detection unit and heat dissipation unit according to the mode judgment result, and executes the differentiated adjustment strategy: (1) Full-function working mode: The solid-state power unit adopts the conventional conduction strategy, the control unit runs at the highest main frequency of 120MHz, the detection unit collects data such as voltage, current, power tube temperature and air duct resistance through the entire channel, the heat dissipation unit automatically adjusts the fan speed according to the power tube temperature, and the communication unit transmits the operating data and logs to the subway train health management platform at full rate, realizing the full functions of on / off control, status detection and fault protection; (2) Low load energy saving mode: The control unit automatically reduces the frequency to 60MHz and shuts down the non-core computing module; The solid-state power unit adopts the minimum conduction loss modulation algorithm to adjust the conduction of semiconductor switching devices. The conduction angle is reduced to reduce conduction loss; the detection unit closes non-core detection channels such as air duct resistance and ambient humidity, and only retains voltage, current and power tube core temperature acquisition; the heat dissipation unit reduces the fan speed to low speed to reduce heat dissipation power consumption because the power tube temperature is 45℃; (3) No-load low power consumption mode: the solid-state power unit cuts off the main power supply circuit and enters the low power consumption standby state, retaining only the core wake-up module, and the power consumption is reduced to less than 10% of the full load; the control unit reduces the frequency to 20MHz and enters the energy-saving operation mode, retaining only the working condition identification and command receiving functions; the detection unit retains only the short circuit and reverse connection fault detection channels and closes all other detection channels; the heat dissipation unit completely shuts down the cooling fan and relies on natural heat dissipation; the communication unit enters the low-speed sleep communication mode, only receiving the air conditioner controller's command and fault trigger signal, and stops the regular data upload.

[0048] Step 4: Rapid switching to energy-saving mode; As the subway train starts, the air conditioning controller sends a "full load" load recovery command, triggering the software mechanism; simultaneously, the detection unit detects a sudden increase in load current from 0A to 20A (≥7.5A) within 8ms, triggering the hardware mechanism. The mode switching module drives the contactor to switch from no-load low-power mode to full-function operating mode within 8ms. Each module quickly completes its function reset, ensuring normal power supply to the air conditioning circuit without any response lag.

[0049] Step 5: Energy-saving mode fault protection; If the detection unit detects a short circuit fault signal in the air conditioning circuit under no-load low power consumption mode, the fault protection module immediately triggers the fault forced exit mechanism. The contactor exits the no-load low power consumption mode within 5ms and starts the hardware and software dual fault protection mechanism. The hardware protection module triggers short circuit blocking within 35μs to cut off the power supply circuit and prevent the fault from escalating.

[0050] The test results of this embodiment show that the power consumption of the 25A AC solid-state contactor decreased from 15W to 5.8W in no-load low-power mode, a reduction of 61.3%; in low-load energy-saving mode, the power consumption decreased from 15W to 9.2W, a reduction of 38.7%; the switching response time from energy-saving mode to full-function working mode is 8ms, and the fault forced exit response time is 5ms, which fully meets the stability and safety requirements of subway train power supply.

[0051] Existing technologies that rely solely on current thresholds to determine low-power modes are prone to misjudgment due to current fluctuations caused by subway train vibrations. For example, depending on a single current threshold, the high-frequency vibrations during subway train operation can cause instantaneous fluctuations in load current, easily misinterpreting "vibration interference" as "operating mode switching," leading to frequent mode starts and stops. This increases device losses and affects power supply stability. Furthermore, hardware-triggered mode switching is susceptible to failure due to hardware malfunctions. For instance, a failure in the hardware detection module or trigger circuit can cause mode switching to fail, resulting in power supply delays due to the inability to exit energy-saving mode, or even safety risks due to the inability to quickly switch to full-function protection mode in case of a fault.

[0052] This invention employs a dual-judgment method combining current threshold and operating condition commands, reducing the false judgment rate to below 1%. Furthermore, a mode-switching anti-jitter mechanism prevents frequent module start-ups and shutdowns caused by frequent fluctuations in operating conditions, extending device lifespan. The fault-forced exit mechanism, in conjunction with dual protection, shortens the fault response time to within 5ms, preventing fault escalation and ensuring that protection actions are unaffected by mode status. The method and system of this invention are not only applicable to solid-state contactors in subway train air conditioning control panels, but can also adaptively adjust parameters such as no-load threshold and low-load threshold, as well as the power consumption adjustment strategies of each module, based on the rated current and operating condition characteristics of different power supply circuits for subway train lighting, braking, and traction. It is highly versatile and can be widely applied to various intelligent solid-state contactors in subway trains.

[0053] The present invention relates to a low-power energy-saving control method and system for intelligent solid-state contactors in subway trains. Based on the existing solid-state contactor hardware architecture, it requires no additional dedicated components, resulting in low modification costs and ease of implementation. It can be directly applied to intelligent solid-state contactors in all high-power power supply circuits of subway trains, including lighting, braking, traction, and air conditioning, enabling dynamic adjustment of contactor power consumption, significantly reducing ineffective power consumption on subway trains, while ensuring power supply stability and fault protection. The technical solution of this invention can be rapidly industrialized and promoted, and can also be used to upgrade the software of existing intelligent solid-state contactors in subway trains, possessing extremely high industrial practicality and market application value.

[0054] Although the invention has been described herein in conjunction with various embodiments, those skilled in the art will understand and implement other variations of the disclosed embodiments by reviewing the accompanying drawings, disclosure, and other materials. In this specification, the word "comprising" does not exclude other components or steps, and "a" or "an" does not exclude multiple components. A single processor or other unit can implement several functions listed in the specification. While certain measures are described in different embodiments, this does not mean that these measures cannot be combined to produce good results.

[0055] Although the invention has been described in conjunction with specific features and embodiments, it is obvious that various modifications and combinations can be made therein without departing from the spirit and scope of the invention. Accordingly, this specification and drawings are merely illustrative of the invention and are considered to cover any and all modifications, variations, combinations, or equivalents within the scope of the invention. Clearly, those skilled in the art can make various alterations and modifications to the invention without departing from its spirit and scope. Thus, if such modifications and modifications fall within the scope of the invention and its equivalents, the invention is also intended to include such modifications and modifications.

Claims

1. A low-power, energy-saving control method for intelligent solid-state contactors in subway trains, characterized in that: Includes the following steps: S1: Real-time acquisition of load current data at the output of the solid-state contactor, receiving operating condition commands, and extracting operating condition characteristics by parsing the load current data and operating condition commands. S2: By comparing the load current data with the preset no-load threshold and low-load threshold, and based on the comparison results and operating condition commands, determine whether the contactor enters full-function operating mode, low-load energy-saving mode, or no-load low-power mode; S3: Based on the determined operating mode, implement differentiated power consumption adjustment strategies for the solid-state power unit, control unit, detection unit, and heat dissipation unit of the solid-state contactor; S4: When load recovery is detected or a load recovery command from the train is received, the control unit drives the contactor to switch from low-load energy-saving mode or no-load low-power mode to full-function operating mode; S5: When a fault signal is detected in low-load energy-saving mode or no-load low-power mode, immediately exit the current mode and activate full-function fault protection.

2. The method according to claim 1, characterized in that, In step S1, the operating condition command comes from the train's upper control system and includes at least one of the following: normal driving, parking standby, night maintenance, traction start, air conditioning full load, and lighting half load.

3. The method according to claim 1, characterized in that, In step S2, the no-load threshold is 5% of the rated current of the solid-state contactor, and the low-load threshold is 30% of the rated current of the solid-state contactor; and the no-load threshold and the low-load threshold are adaptively adjusted according to the rated current of different power supply circuits for lighting, braking, traction and air conditioning of the subway train.

4. The method according to claim 1, characterized in that, In step S2, the rules for determining the operating mode specifically include: if the load current is greater than or equal to the low load threshold, and / or the operating condition command is a normal power supply command, it is determined to be a full-function operating mode; if the no-load threshold is less than the load current and less than the low load threshold, and / or the operating condition command is a low load power supply command, it is determined to be a low load energy-saving mode; if the load current is less than or equal to the no-load threshold, and / or the operating condition command is a no-load standby command, it is determined to be a no-load low power consumption mode; the mode determination period is 500ms.

5. The method according to claim 1, characterized in that, In step S3, the power consumption adjustment strategy of the full-function working mode is as follows: the solid-state power unit adopts a conventional conduction strategy, the control unit operates at the highest working frequency, the detection unit collects data in real time across all channels, the heat dissipation unit automatically adjusts the heat dissipation power according to the power tube temperature, and the communication unit transmits data at full rate.

6. The method according to claim 1, characterized in that, In step S3, the power consumption adjustment strategy of the low-load energy-saving mode includes: the control unit reduces the frequency to the medium main frequency of 50~80MHz and shuts down the non-core computing modules; the solid-state power unit uses the minimum conduction loss modulation algorithm to adjust the conduction angle of the semiconductor switching device; the detection unit shuts down the non-core detection channels and only retains the acquisition of voltage, current and core temperature; the heat dissipation unit appropriately reduces the heat dissipation power according to the temperature of the power tube.

7. The method according to claim 1, characterized in that, In step S3, the power consumption adjustment strategy of the idle low-power mode includes: the solid-state power unit cuts off the main power supply circuit and enters a low-power standby state, retaining only the core wake-up module; the control unit reduces the main frequency to the minimum ≤20MHz and enters the energy-saving operation mode, retaining only the working condition identification and command receiving functions; the detection unit retains only the idle fault detection channel; the heat dissipation unit completely stops active heat dissipation; the communication unit enters a low-speed sleep communication mode, receiving only commands and fault trigger signals.

8. The method according to claim 1, characterized in that, In step S4, a dual switching mechanism of hardware triggering and software triggering is adopted. Hardware triggering is triggered when the load current suddenly increases within 10ms and exceeds the low load threshold, while software triggering is triggered when the train upper-level load recovery command is received.

9. The method according to claim 1, characterized in that, In steps S2 to S5, a mode switching anti-shake mechanism is set, and the interval between two adjacent operation mode switches is not less than 3 seconds; in step S5, the fault signal includes at least one of short circuit, overvoltage, reverse connection, and overtemperature fault signals, and the full-function fault protection is a dual fault protection mechanism combining hardware and software.

10. A low-power energy-saving control system for a smart solid-state contactor in a subway train, used to implement the method described in any one of claims 1 to 9, characterized in that, The system includes a working condition acquisition module, a mode determination module, a power consumption adjustment module, a mode switching module, and a fault protection module. The working condition acquisition module is used to acquire load current data from the output terminal of the solid-state contactor in real time, receive working condition commands from the train's upper control system, and analyze the data and commands to extract working condition characteristics. The mode determination module has built-in preset no-load thresholds and low-load thresholds, used to compare the load current data with the thresholds and determine the contactor's operating mode based on the working condition characteristics. The power consumption adjustment module is electrically connected to the solid-state power unit, control unit, detection unit, and heat dissipation unit of the solid-state contactor, and is used to send differentiated power consumption adjustment commands to each module according to the operating mode. The mode switching module is used to detect the load recovery status, receive load recovery commands, and drive the contactor to switch from energy-saving mode to full-function operating mode; the energy-saving mode includes a low-load energy-saving mode or a no-load low-power mode. The fault protection module is used to detect fault signals in the energy-saving mode, drive the contactor to exit the current energy-saving mode and activate the full-function fault protection.

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