Self-adaptive paver screed electric heating control method and system

Abstract

The invention provides a self-adaptive paver screed electric heating control method and system, and particularly relates to the technical field of engineering machinery electric control, and the method comprises the steps: obtaining the current value of each phase at the upper ends of a plurality of air switches in an electric heating control system in real time through a current monitoring unit; the logic control unit calculates the sum of each single-phase current, compares the sum with a preset overload current value and a preset protection current value, executes current state judgment, controls a contactor to be closed or outputs an alarm signal according to a judgment result, and closes the system; and meanwhile, for each air switch, calculating the current difference of any two phases under the same air switch based on the current value of each phase, comparing the current difference with a preset current difference value, and when the current difference is greater than the preset value, outputting a fault alarm signal and disconnecting the corresponding contactor. According to the method, the generator overload risk caused by overlimit of the heating power when the paver is adaptive to multiple types of screed plates can be avoided, and quick positioning of the open circuit fault of the heating strip is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of electrical control of engineering machinery, and in particular to a method and system for controlling electric heating of an adaptive paving machine screed. Background Art

[0002] Asphalt pavers, as core equipment for high-grade highway construction, require screeds that adapt to varying construction requirements (telescopic, mechanical, and end-telescopic) and widths (6-12 meters). With the increasing complexity of municipal projects, frequent screed replacements by users lead to significant load fluctuations in the electric heating control system. The mismatch between the generator's rated power (e.g., 32kW) and the total power of the screed's heating strips (up to 40kVA) can easily lead to generator overload and burnout. Furthermore, heating strip shorting is a frequent problem. Traditional manual diagnostics, which fail to accurately determine the three-phase current balance section by section, are time-consuming and prone to misjudgment, severely impacting construction efficiency and equipment safety.

[0003] Current solutions mainly focus on two categories: 1. Leakage protection (e.g., patent CN109235203B): locates the fault section through leakage detection, but does not involve current monitoring and generator overload protection; 2. Power boost (e.g., patent CN118621659A): This improves heating efficiency by adjusting the generator voltage. However, it cannot dynamically adapt to the power requirements of different screeds and still relies on fixed hardware configuration.

[0004] Neither of these two solutions solves the core contradiction: how to monitor the current in real time and dynamically adjust the heating strategy to balance the safety of the generator and the power requirements of different ironing boards. In summary, how to solve the risk of generator overload caused by excessive heating power when the paver is adapted to multiple types of screeds, and at the same time quickly locate the short circuit fault of the heating strip, is an urgent problem to be solved. Summary of the Invention

[0005] The main purpose of the present invention is to provide an adaptive paver screed electric heating control method and system, so as to at least solve the technical problem of generator overload risk caused by excessive heating power when the paver is adapted to multiple types of screeds, and at the same time realize the rapid positioning of heating strip circuit faults, thereby avoiding the risk of generator overload caused by excessive heating power when the paver is adapted to multiple types of screeds, and at the same time realize the rapid positioning of heating strip circuit faults.

[0006] In order to achieve the above objectives, the present invention provides a method and system for controlling electric heating of an adaptive paver screed.

[0007] In a first aspect, the present invention provides a method for controlling electric heating of an adaptive paver screed, the method comprising: The current monitoring unit is used to obtain the current values ​​of each phase at the upper ends of multiple circuit breakers in the electric heating control system in real time; In the logic control unit, a sum of the single-phase currents is calculated based on the current values ​​of the phases, and the sum of the single-phase currents is compared with a preset overload current value and a preset protection current value to perform current state determination; When the sum of all the single-phase currents is less than the preset overload current value, all contactors are controlled to be closed to execute the full-power heating mode; When the sum of any of the single-phase currents is greater than the preset overload current value and less than the preset protection current value, performing zoned alternating heating control according to the accumulated timing result, wherein the accumulated timing result is used to indicate the duration of the state in which the sum of any of the single-phase currents is greater than the preset overload current value and less than the preset protection current value; When the sum of any of the single-phase currents is greater than the preset protection current value, an overload alarm signal is output and the electric heating control system is shut down; For each circuit breaker, the current difference between any two phases under the same circuit breaker is calculated based on the current values ​​of each phase, and the current difference is compared with the preset current difference value; when the current difference is greater than the preset current difference value, the fault alarm signal corresponding to the circuit breaker is output and the contactor corresponding to the circuit breaker is disconnected.

[0008] Specifically, the current monitoring unit is used to obtain the current values ​​of each phase of the upper ends of multiple circuit breakers in the electric heating control system in real time, including: The instantaneous current values ​​of the U-phase, V-phase and W-phase at the upper end of each circuit breaker are collected through current transformers; The instantaneous current value is filtered to obtain a steady-state current value as the current value of each phase.

[0009] Specifically, in the logic control unit, the sum of the single-phase currents is calculated based on the current values ​​of the phases, and the sum of the single-phase currents is compared with a preset overload current value and a preset protection current value to perform current state determination, including: Calculate the sum of the currents of the U phase, the V phase, and the W phase on the multiple circuit breakers to obtain the sum of the U phase current, the V phase current, and the W phase current; respectively comparing the U-phase current sum, the V-phase current sum, and the W-phase current sum with the preset overload current value and the preset protection current value; A current state identifier is generated according to the comparison result, where the current state identifier includes a normal identifier, an overload identifier, or a protection identifier.

[0010] Specifically, when the sum of all the single-phase currents is less than the preset overload current value, controlling all contactors to be attracted to execute the full-power heating mode includes: When the current state is marked as normal, a closing instruction is sent to all contactors; Monitor the contactor feedback signal. When all contactors are confirmed to be closed, maintain full power heating until the temperature reaches the preset value.

[0011] Specifically, when the sum of any of the single-phase currents is greater than the preset overload current value and less than the preset protection current value, performing the zoned alternating heating control according to the accumulated timing result includes: When the current status indicator is an overload indicator, the overload duration is started to accumulate time; If the accumulated time is less than the preset time threshold, all contactors are controlled to close; If the accumulated duration is greater than or equal to the preset duration threshold, the contactors are divided into three groups for cyclic execution: The first group: controls KM1, KM2, and KM4 contactors to close, and KM3 and KM5 to disconnect; The second group: control KM1, KM3, KM5 contactors to be closed, and KM2 and KM4 to be disconnected; The third group: controls KM2, KM3, KM4, and KM5 contactors to close and KM1 to disconnect; The duration of each group of attraction is equal to the preset alternating heating time.

[0012] Specifically, when the sum of any of the single-phase currents is greater than the preset protection current value, an overload alarm signal is output and the electric heating control system is shut down, including: When the current state indicator is a protection indicator, the sound and light alarm is triggered to output the overload alarm signal; Send disconnect commands to all contactors synchronously and display the shutdown status on the human-machine interface.

[0013] Specifically, for each circuit breaker, the current difference between any two phases under the same circuit breaker is calculated based on the current values ​​of each phase, and the current difference is compared with a preset current difference value; when the current difference is greater than the preset current difference value, a fault alarm signal corresponding to the circuit breaker is output and the contactor corresponding to the circuit breaker is disconnected, including: For the current circuit breaker, calculate the absolute value of the UV phase current difference, the absolute value of the VW phase current difference, and the absolute value of the WU phase current difference respectively; When the absolute value of any current difference is greater than the preset current difference, it is determined that the heating strip corresponding to the current circuit breaker has a circuit breaker fault; Output a fault alarm signal including the circuit breaker number corresponding to the current circuit breaker, and disconnect the contactor uniquely corresponding to the current circuit breaker. After disconnecting the contactor corresponding to the current circuit breaker, re-execute the current state determination.

[0014] In a second aspect, the present invention provides an adaptive paver screed electric heating control system, wherein the control system applies the control method described in the first aspect, and the control system includes: The current monitoring unit is used to obtain the current values ​​of each phase at the upper ends of multiple circuit breakers in the electric heating control system in real time; a logic control unit connected to the current monitoring unit, the logic control unit being configured to calculate a sum of the single-phase currents based on the current values ​​of the phases; and compare the sum of the single-phase currents with a preset overload current value and a preset protection current value to perform current state determination; a control execution unit connected to the logic control unit, the control execution unit being configured to control all contactors to close to execute a full-power heating mode when the sum of all single-phase currents is less than the preset overload current value; to execute zoned alternating heating control according to a cumulative timing result when the sum of any single-phase current is greater than the preset overload current value and less than the preset protection current value, wherein the cumulative timing result is used to indicate the duration of the overload state; and to output an overload alarm signal and shut down the electric heating control system when the sum of any single-phase current is greater than the preset protection current value. A fault diagnosis unit is connected to the current monitoring unit and the logic control unit. The fault diagnosis unit is used to calculate the current difference between any two phases under the same circuit breaker based on the current values ​​of each phase for each circuit breaker; compare the current difference with a preset current difference value, and when the difference is greater than the preset current difference, output a fault alarm signal corresponding to the circuit breaker and disconnect the contactor corresponding to the circuit breaker.

[0015] Specifically, the current monitoring unit includes: Current transformer array, used to collect the instantaneous current values ​​of the U-phase, V-phase and W-phase at the upper end of each circuit breaker; A filtering module is connected to the current transformer array, and is used to filter the instantaneous value of the current and output a steady-state current value as the current value of each phase.

[0016] Specifically, the logic control unit includes: a sum calculation module, configured to respectively calculate the sum of the currents of the U phase, the V phase, and the W phase on the plurality of circuit breakers, and output the sum of the U phase current, the V phase current, and the W phase current; a comparison module connected to the sum calculation module, the comparison module being used to compare the sum of the U-phase current, the V-phase current and the W-phase current with a preset overload current value and a preset protection current value, respectively; A state identification generating module is connected to the comparison module, and is used to generate a current state identification according to the comparison result. The current state identification includes a normal identification, an overload identification or a protection identification.

[0017] The present application provides an adaptive paving machine screed electric heating control method and system. This method uses a current monitoring unit to obtain the current values ​​of each phase at the upper ends of multiple circuit breakers in the electric heating control system in real time. The logic control unit calculates the sum of each single-phase current based on this, and compares it with the preset overload current value and the preset protection current value to determine the current state. If the sum of each single-phase current is less than the preset overload current value, all contactors are controlled to be attracted and enter the full-power heating mode; if the sum of any single-phase current is between the preset overload and protection current values, the partitioned alternating heating control is performed according to the accumulated timing results; if it is greater than the preset protection current value, an overload alarm signal is output and the system is shut down. In addition, for each circuit breaker, the current difference between any two phases under the same circuit breaker is calculated and compared with the preset current difference. When the difference is too large, a fault alarm signal is output and the corresponding contactor is disconnected, effectively avoiding the risk of generator overload and realizing rapid positioning of the heating strip circuit breaker fault. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings: Figure 1 A flow chart of the adaptive paver screed electric heating control method provided in this application; Figure 2 A connection diagram of the adaptive paver screed electric heating control system provided in this application; Figure 3 This is a schematic diagram of the structure of the adaptive paver screed electric heating control system provided in this application.

[0019] The above drawings illustrate specific embodiments of the present application, which will be described in more detail below. These drawings and the textual description are not intended to limit the scope of the present application in any way, but rather to illustrate the concepts of the present application to those skilled in the art by reference to specific embodiments. DETAILED DESCRIPTION

[0020] To make the purpose, technical solutions, and advantages of this application more clear, the technical solutions in this application will be clearly and completely described below in conjunction with the drawings in this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0021] The terms "first," "second," "third," "fourth," and so forth (if any) in the description and claims of the present invention and in the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a particular order or sequential sequence. It should be understood that the terms used in this manner are interchangeable where appropriate, such that the embodiments of the present invention described herein can be practiced in sequences other than those illustrated or described herein.

[0022] In the present invention, words such as "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described in this application as "exemplary" or "for example" should not be construed as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0023] The present application provides an adaptive paving machine screed electric heating control method and system. This method uses a current monitoring unit to obtain the current values ​​of each phase at the upper ends of multiple circuit breakers in the electric heating system. The logic control unit calculates the sum of the currents of each single phase based on this, and compares it with the preset overload and protection current values ​​to determine the current state. The contactor action is controlled according to different states to achieve full-power or partitioned alternating heating mode. When the limit is exceeded, an alarm is output and the system is shut down. At the same time, the current difference between any two phases under the same circuit breaker is calculated and compared with the preset value. When the difference exceeds the preset value, a fault alarm is output and the corresponding contactor is disconnected to avoid the risk of generator overload and quickly locate the circuit breaker fault of the heating strip.

[0024] The following specific embodiments describe in detail the technical solution of the present application and how the technical solution of the present application solves the above-mentioned technical problems. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0025] Figure 1 The flowchart of the adaptive paving machine screed electric heating control method provided in this application is as follows: Figure 1 As shown in FIG, the adaptive paver screed electric heating control method provided by this embodiment includes: S101: Obtain the current values ​​of each phase of the upper ends of multiple circuit breakers in the electric heating control system in real time through a current monitoring unit.

[0026] Specifically, the current monitoring unit is used to obtain the current values ​​of each phase of the upper ends of multiple circuit breakers in the electric heating control system in real time, including: The instantaneous current values ​​of the U-phase, V-phase and W-phase at the upper end of each circuit breaker are collected through current transformers; The instantaneous current value is filtered to obtain a steady-state current value as the current value of each phase.

[0027] During implementation, step S101 specifically includes: 1. Current transformer signal acquisition 1.1 Hardware Configuration: Use a through-type current transformer with an accuracy level of 0.5, and connect its primary side in series to the U-phase, V-phase, and W-phase conductor loops at the upper end of the circuit breaker.

[0028] 1.2 Signal conversion: The secondary side of the current transformer outputs a 0-5A AC current signal, which is converted into a 0-1.25V voltage signal through a 250Ω precision sampling resistor.

[0029] 1.3 Data acquisition: A 16-bit ADC (analog-to-digital converter) is used to collect voltage signals at a sampling rate of 1000 times per second to generate a series of instantaneous current values:

[0030] in: : The instantaneous value of the U-phase current at the nth sampling point (unit: A); : The instantaneous value of the V-phase current at the nth sampling point; : The instantaneous value of the W-phase current at the nth sampling point; N: The number of sampling points in each 200ms sampling period (N=200).

[0031] 2. Filtering to generate steady-state current value 2.1 Filtering algorithm: FIR low-pass filter designed by window function method (Hanning window, order M=50), cutoff frequency (Eliminate high-frequency noise caused by construction vibration).

[0032] 2.2 Difference equation:

[0033] Where: : Steady-state current value of the kth output point; : FIR filter coefficients (generated by MATLAB fdatool); : Input current instantaneous value sequence.

[0034] 2.3 Execution steps: For each phase current instantaneous value sequence , , Apply the above FIR filtering independently; Take the arithmetic mean of the filtered data in each 200ms window as the steady-state current value of the window: ; (V phase and W phase are calculated by the same principle , ).

[0035] Output result: Steady-state current value of U phase, V phase and W phase at the upper end of each circuit breaker , , , as the current value of each phase in step S101.

[0036] This embodiment physically collects instantaneous three-phase current signals through current transformers, converts them into measurable voltages using precision resistors, and then eliminates high-frequency noise interference generated by the paver's engine vibration using an FIR low-pass filter (cutoff frequency 10Hz, order 50) based on a Hanning window design. Finally, the arithmetic mean of the filtered data is calculated within a 200ms window, outputting a steady-state current value that truly reflects the operating status of the heating strips. This process eliminates the problem of false triggering caused by current signal fluctuations in construction environments, providing stable and reliable data input for the subsequent current state determination step (S102). The linear phase characteristic of the FIR filter ensures the synchronization of the current signals of each phase, preventing false positives from three-phase imbalance.

[0037] S102: In a logic control unit, a sum of each single-phase current is calculated based on the current values ​​of each phase, and the sum of each single-phase current is compared with a preset overload current value and a preset protection current value to perform current state determination.

[0038] Specifically, in the logic control unit, the sum of the single-phase currents is calculated based on the current values ​​of the phases, and the sum of the single-phase currents is compared with a preset overload current value and a preset protection current value to perform current state determination, including: Calculate the sum of the currents of the U phase, the V phase, and the W phase on the multiple circuit breakers to obtain the sum of the U phase current, the V phase current, and the W phase current; respectively comparing the U-phase current sum, the V-phase current sum, and the W-phase current sum with the preset overload current value and the preset protection current value; A current state identifier is generated according to the comparison result, where the current state identifier includes a normal identifier, an overload identifier, or a protection identifier.

[0039] During implementation, step S102 specifically includes: 1. Calculation of the total current of each single phase 1.1 Input data: Get the steady-state current value of each circuit breaker from S101 ( , , ), corresponding to the U / V / W three-phase data of 5 circuit breakers (F1-F5).

[0040] 1.2 Calculation process: Use arithmetic accumulation algorithm to calculate the total current of each phase on all circuit breakers:

[0041] in: : Total current of phase U (unit: A); : U-phase steady-state current value at the upper end of circuit breaker Fk (k=1,2,3,4,5); V phase ( )、W phase( ) The calculation is similar.

[0042] 2. Threshold comparison logic 2.1 Preset parameters: Preset overload current value (e.g. 53.4A); Preset protection current value (such as 60A).

[0043] 2.2 Independent comparison rules (three-phase parallel execution): like < →U phase status = normal; like ≤ < →U phase status = overload; like ≥ →U phase status = protection.

[0044] The V phase and W phase are judged independently using the same rules.

[0045] 3. Current status identification generation 3.1 Identification coding rules (as shown in Table 1): Table 1: Identification coding rules 3.2 Execution steps: Generate a 3-bit binary code according to the rules in Table 1 above (e.g., U phase overload = 10, V phase normal = 01, W phase normal = 01 → combination code 100101); Map the combination code to the identification value (0x01 / 0x02 / 0x03) through the table lookup method; Output flags to the logic control unit register. This embodiment calculates the sum of the three-phase currents U / V / W by an arithmetic accumulation algorithm ( , , ), using independent threshold comparison rules (e.g. =53.4A, =60A) classifies each phase's status (normal / overload / protection). Ultimately, a unique current status identifier (0x01 / 0x02 / 0x03) is generated based on a three-phase status combination lookup table. This process converts raw current data from S101 into a machine-determined status signal, providing precise input for subsequent tiered control (S103-S105). The independent three-phase comparison mechanism ensures comprehensive monitoring of the generator's three-phase imbalance risk.

[0046] S103: When the sum of all the single-phase currents is less than the preset overload current value, all contactors are controlled to be closed to execute the full-power heating mode.

[0047] Specifically, when the sum of all the single-phase currents is less than the preset overload current value, controlling all contactors to be attracted to execute the full-power heating mode includes: When the current state is marked as normal, a closing instruction is sent to all contactors; Monitor the contactor feedback signal. When all contactors are confirmed to be closed, maintain full power heating until the temperature reaches the preset value.

[0048] During implementation, step S103 specifically includes: 1. Contactor closing control 1.1 Trigger conditions: When the current status identification register value in the logic control unit is 0x01 (normal identification), the closing instruction sending process is executed.

[0049] 1.2 Command transmission protocol: Using the Modbus RTU protocol, hexadecimal command frames are sent to the drivers of the five contactors (KM1-KM5) via the RS-485 bus.

[0050] 1.3 Implementation Mechanism: Send command frames to KM1-KM5 drivers in sequence and cycle; Each transmission interval is 50ms to avoid bus conflicts; After the driver receives the command, the drive coil is energized to physically close the contactor.

[0051] 2. Contactor status monitoring 2.1 Feedback signal acquisition: Connect a 0.1Ω sampling resistor in series at each contactor output end to measure the load current value as the feedback signal; If the feedback current value lasts for 200ms≥5A (the minimum operating current of the heating strip), it is determined that the contactor is reliably attracted.

[0052] 2.2 Status verification logic:

[0053] Where: k: contactor number (k=1,2,3,4,5); : The contactor k's energizing state (1=energized, 0=not energized).

[0054] 2.3 Global status determination: When all 5 contactor states meet the following conditions: .

[0055] 3. Full power maintenance control 3.1 Temperature monitoring mechanism: read the screed temperature sensor data and convert it into digital quantity through 4-20mA transmitter .

[0056] 3.2 Heating maintenance conditions:

[0057] Where: : Preset heating temperature (such as 120℃); : Current real-time temperature.

[0058] 3.3 Execution process: Continuously monitor temperature and contactor status ; If any contactor is in abnormal state ( =0), immediately resend the closing command; when ≥ When , send a disconnect command to terminate heating.

[0059] This embodiment uses the Modbus RTU protocol to send a standard command frame (function code 0x06) to the contactor driver to implement contact closure control. The load current threshold judgment method (≥5A for 200ms) is used to verify the reliability of the contactor's physical pull-in. Under the closed-loop control of the temperature sensor feedback (PT100 + 4-20mA transmission), full power heating is maintained until the preset temperature value is reached. This process solves the heating failure problem caused by contactor virtual connection, ensuring that the ironing board quickly heats up to the required construction temperature under normal current conditions, and the bus communication mechanism (RS-485+Modbus) ensures control stability in industrial environments.

[0060] S104: When the sum of any of the single-phase currents is greater than the preset overload current value and less than the preset protection current value, performing zoned alternating heating control according to the accumulated timing result.

[0061] Specifically, when the sum of any of the single-phase currents is greater than the preset overload current value and less than the preset protection current value, performing the zoned alternating heating control according to the accumulated timing result includes: When the current status indicator is an overload indicator, the overload duration is started to accumulate time; If the accumulated time is less than the preset time threshold, all contactors are controlled to close; If the accumulated duration is greater than or equal to the preset duration threshold, the contactors are divided into three groups for cyclic execution: The first group: controls KM1, KM2, and KM4 contactors to close, and KM3 and KM5 to disconnect; The second group: control KM1, KM3, KM5 contactors to be closed, and KM2 and KM4 to be disconnected; The third group: controls KM2, KM3, KM4, and KM5 contactors to close and KM1 to disconnect; The duration of each group of attraction is equal to the preset alternating heating time.

[0062] During implementation, step S104 specifically includes: 1. Overload timing start and accumulation 1.1 Trigger condition: When the logic control unit detects that the current status flag register value is 0x02 (overload flag), the timing process is started.

[0063] 1.2 Timing mechanism: A high-precision real-time clock (RTC) is used to accumulate the overload duration, with a time resolution of 1 second.

[0064] Timing formula:

[0065] Where: : cumulative duration (unit: seconds); : The time increment for each loop (fixed at 1 second).

[0066] 1.3 Storage Update: Each cycle will Write to non-volatile memory (such as EEPROM) to prevent loss during power failure.

[0067] 2. Full power heating maintenance control 2.1 Execution conditions: If < ( is the preset duration threshold, such as 3180 seconds = 53 minutes).

[0068] 2.2 Control action: Send closing instructions to all contactors (KM1-KM5) (same as Modbus RTU protocol of S103) to maintain full power heating mode.

[0069] 3. Partition alternating heating control 3.1 Trigger conditions: If ≥ .

[0070] 3.2 Group loop logic: 3.2.1 The first group of control (duration = preset alternating heating time , such as 300 seconds): Pull-on contactor: KM1, KM2, KM4; Disconnect contactor: KM3, KM5; Command frame example (KM1 is energized): 01 06 00 01 FF 00 CRC.

[0071] 3.2.2 The second group of controls (duration = ): Pull-on contactor: KM1, KM3, KM5; Disconnect contactors: KM2, KM4.

[0072] 3.2.3 The third group of controls (duration = ): Pull-on contactor: KM2, KM3, KM4, KM5; Disconnect contactor: KM1.

[0073] 3.3 Loop execution mechanism: Use the state machine model to switch groups: current group = (current group mod 3) + 1.

[0074] After each group is executed, reset the countdown timer to , switch to the next group.

[0075] 4. Continuous monitoring of overload status 4.1 Real-time monitoring of current status identification: If the flag changes from overload (0x02) to normal (0x01) or protection (0x03), the zone heating is terminated immediately and the process jumps to the corresponding process.

[0076] 4.2 Conditions for clearing the accumulated time: =0 when ≥43200 seconds (12 hours). In this embodiment, the high-precision RTC accumulates the duration of the overload , when the accumulated time is less than the preset threshold (For Stanford generators, overload is allowed for 53 minutes every 12 hours) to maintain full power heating, and when the threshold is exceeded, the zone alternating heating control is activated. This control uses three groups of fixed contactor combinations (KM1 / KM2 / KM4, KM1 / KM3 / KM5, KM2 / KM3 / KM4 / KM5) for cyclic execution, and the working time of each group is determined by the preset alternating heating time. This solution dynamically allocates heating power when the generator is overloaded, preventing damage from exceeding capacity while ensuring continuous heating of the screed. This solution addresses the balance between system protection and heating efficiency when the paver is equipped with a high-power screed.

[0077] S105: When the sum of any of the single-phase currents is greater than the preset protection current value, an overload alarm signal is output and the electric heating control system is shut down.

[0078] Specifically, when the sum of any of the single-phase currents is greater than the preset protection current value, an overload alarm signal is output and the electric heating control system is shut down, including: When the current state indicator is a protection indicator, the sound and light alarm is triggered to output the overload alarm signal; Send disconnect commands to all contactors synchronously and display the shutdown status on the human-machine interface.

[0079] During implementation, step S105 specifically includes: 1. Sound and light alarm triggering process Alarm activation: When the current status flag changes to the protection flag (value 0x03), the sound and light alarm is activated.

[0080] Light alarm implementation: The red LED indicator flashes 3 times per second (0.5 seconds each on and off) and is connected to the controller output terminal through a 220 ohm current limiting resistor.

[0081] Acoustic alarm realization: The piezoelectric buzzer emits a continuous sound of 2000 Hz and is driven by a pulse signal with a 70% duty cycle.

[0082] Alarm mode: 3 short beeps (0.5 second sound + 0.5 second silence) every 60 seconds until manually reset.

[0083] 2. Contactor synchronous disconnection control Power-off command transmission: Send a broadcast command (device address 00) via the RS-485 bus, and the command content is "disconnect all contactors".

[0084] Command format: Standardized Modbus RTU data frame containing register address 0001 and disconnect command code 0000.

[0085] Status verification: Monitors the contactor load current and automatically resends the command if it does not drop below 0.5 amps within 500 milliseconds.

[0086] 3. Human-machine interface status display Status update: Send Modbus TCP data packets via Ethernet, including the device address, status register address and shutdown flag.

[0087] Visual cue: Displays 32-pixel-high red "Overload Shutdown" text (RGB color value #FF0000) in the lower right corner of the touch screen.

[0088] Time record: Synchronously display the real-time shutdown timestamp in the format of year-month-day hour:minute:second. When a system overload is detected, this embodiment provides an immediate warning via an audible and visual alarm (3Hz flashing red light + 2kHz beeping). A broadcast command simultaneously shuts off power to all contactors, and the shutdown status and time are updated in real time on the human-machine interface. This solution provides millisecond-level emergency power-off protection and establishes a comprehensive fault tracing mechanism, ensuring operators can quickly locate the problem and reset the system.

[0089] S106: For each circuit breaker, calculate the current difference between any two phases under the same circuit breaker based on the current values ​​of each phase, and compare the current difference with a preset current difference value; when the current difference is greater than the preset current difference value, output a fault alarm signal corresponding to the circuit breaker and disconnect the contactor corresponding to the circuit breaker.

[0090] Specifically, for each circuit breaker, the current difference between any two phases under the same circuit breaker is calculated based on the current values ​​of each phase, and the current difference is compared with a preset current difference value; when the current difference is greater than the preset current difference value, a fault alarm signal corresponding to the circuit breaker is output and the contactor corresponding to the circuit breaker is disconnected, including: For the current circuit breaker, calculate the absolute value of the UV phase current difference, the absolute value of the VW phase current difference, and the absolute value of the WU phase current difference respectively; When the absolute value of any current difference is greater than the preset current difference, it is determined that the heating strip corresponding to the current circuit breaker has a circuit breaker fault; Output a fault alarm signal including the circuit breaker number corresponding to the current circuit breaker, and disconnect the contactor uniquely corresponding to the current circuit breaker. After disconnecting the contactor corresponding to the current circuit breaker, re-execute the current state determination.

[0091] During implementation, step S106 specifically includes: 1. Calculation of current difference under the same circuit breaker 1.1 Input data: Get the current steady-state current value of the circuit breaker (for example, circuit breaker F1) from S101 (U phase), (V phase), (W phase).

[0092] 1.2 Difference calculation: The absolute value calculation method is used to generate three sets of current differences:

[0093] Where: : Absolute value of UV phase current difference (unit: A); Other differences are defined similarly.

[0094] 2. Circuit breaker fault determination 2.1 Judgment conditions: If any of the following conditions are met: ; The preset current difference (such as 5A) is equal to the rated current value of a single heating strip.

[0095] 2.2 Fault Location: It is determined that the heating strip corresponding to the circuit breaker has a circuit breaker fault (for example, circuit breaker F1 corresponds to the basic middle plate heating strip).

[0096] 3. Fault alarm and contactor disconnection 3.1 Alarm signal generation: Send alarm data frame to the human-machine interface via RS-485 bus: Device address | Function code 0x06 | Register address (open circuit breaker number) | Fault code 0xEE.

[0097] Example: F1 alarm frame for open circuit: 01 06 00 01 EE CRC.

[0098] 3.2 Contactor disconnection control: Use a one-to-one mapping rule to disconnect the corresponding contactor (e.g., circuit breaker F1 → contactor KM1); Send Modbus RTU command: device address | function code 0x06 | register address | disconnect command 0x0000.

[0099] 4. System status reset Restart determination process: After the contactor is disconnected, the current state determination step of S102 is executed again to update the system state. In this embodiment, the absolute value of the three-phase current difference under the same circuit breaker is calculated ( ), when any difference exceeds the preset current difference The system immediately detects a heater strip short circuit fault and sends an address-based alarm signal based on the circuit breaker number (e.g., F1). It also simultaneously disconnects the corresponding contactor (e.g., KM1). After the fault is resolved, the current status determination process (S102) is immediately restarted, enabling system self-recovery. This solution transitions from traditional manual maintenance to automated location tracking, eliminating the potential risk of three-phase imbalance caused by heater strip short circuits and improving maintenance efficiency by over 80%.

[0100] The present embodiment provides an adaptive electric heating control method for a paving machine screed plate. The method uses a current monitoring unit to collect the current values ​​of each phase at the upper ends of multiple circuit breakers in the electric heating control system in real time. The logic control unit calculates the sum of the currents of each single phase based on these current values, and compares it with the preset overload current value and the preset protection current value to complete the current state judgment. If the sum of the currents of each single phase is less than the preset overload current value, all contactors are controlled to be attracted and the full-power heating mode is turned on; if the sum of the currents of any single phase is between the preset overload and protection current values, the partitioned alternating heating control is performed according to the accumulated timing results. Once the sum of the currents of any single phase is greater than the preset protection current value, an overload alarm signal is immediately output and the system is shut down. In addition, for each circuit breaker, the current difference between any two phases under the same circuit breaker is calculated and compared with the preset current difference. When the difference exceeds the limit, a fault alarm signal is output and the corresponding contactor is disconnected, effectively avoiding the risk of generator overload and realizing rapid positioning of the heating strip circuit breaker fault.

[0101] This application also provides an optional embodiment (part) of a method for controlling the electric heating of an adaptive paver screed. The specific control method is as follows: When the paver turns on the electric heating function to heat the ironing plate, the control switch first sends a command to turn on the electric heating function. After receiving the command, the logic control unit will control the engine speed to reach more than 1400 rpm, thereby driving the generator to rotate and reach the rated voltage of the electric heating strip.

[0102] The logic control unit determines the current temperature value fed back by the temperature sensor and the preset electric heating temperature value. If the current sensor temperature value is lower than the preset electric heating temperature value, heating is started, driving the contactor to attract, thereby supplying power to the electric heating strips and heating the screed. If the current sensor temperature value is higher than the electric heating temperature value, the contactor is opened, stopping the power supply to the electric heating strips.

[0103] The control method of the present invention is that during this process, the current monitoring unit monitors the three-phase current value of each circuit breaker in real time and feeds it back to the logic control unit. The logic control unit judges the state of the electric heating system according to the current feedback value and adopts different control methods.

[0104] The present invention can set the overload current value in the logic control unit , protection current value , the difference between the two currents , alternating heating time , Electric heating temperature difference These parameters are used to calibrate the various states of electric heating.

[0105] For general AC generators, manufacturers will indicate two key parameters: rated power , rated capacity Taking the Stanford PI144J2 generator as an example, its rated power , rated capacity , rated voltage Since the AC system has P= At the same time, the electric heating strip is a resistive load, and the power factor is 1, so = / .

[0106] According to the characteristics of this generator, it is allowed to operate above 110% of the rated power and below the rated capacity for 53 minutes every 12 hours.

[0107] 110% rated current , the maximum allowed current of the generator = 60A.

[0108] Therefore, when the current is less than 53.4A, the generator can work without restrictions; when the current is greater than 53.4A and less than 60A, it can work for 53 minutes every 12 hours; if the current is greater than 60A, it must stop working immediately.

[0109] Set the parameter overload current value Set to 110% of the rated current of the generator, and set the protection current value Set to the maximum allowable current of the generator.

[0110] When the sum of the single-phase currents is less than the overload current For example, in the U phase of the three phases, the circuit breaker F1-U phase current is , the circuit breaker F2-U phase current is , the circuit breaker F3-U phase current is , the circuit breaker F4-U phase current is , the circuit breaker F5-U phase current is Similarly, for phases V and W, we have , and , and .

[0111] At this time, the electric system is working normally and the five contactors are synchronously closed. If this setting is reasonable, the power of the generator will be fully utilized to meet the needs of various types and widths of ironing boards.

[0112] When the sum of the single-phase currents is greater than the overload current And less than the protection current When, that is: , or , or .

[0113] At this time, the logic control unit accumulates the time for this state. If the accumulated time is less than 53 minutes within 12 hours, the five contactors are synchronously closed and all the screeds are heated synchronously. If the accumulated time reaches 53 minutes within 12 hours, the zone heating function is executed. KM1 / KM2 / KM4 is the first group, KM1 / KM3 / KM5 is the second group, and KM2 / KM4 / KM3 / KM5 is the third group. The three groups are heated in a cycle, and the time for each group is the alternating heating time. When the actual required power is much greater than the generator power, this setting can protect the electric heating system and maintain the electric heating function by appropriately reducing the heating power.

[0114] When the sum of the single-phase currents is greater than the protection current When, that is: , or , or .

[0115] The logic control unit outputs a current protection alarm and displays it on the human-machine interface of the logic control unit, and at the same time shuts down the electric heating function.

[0116] For the same circuit breaker F, if the configuration is proper, the electric heating strips should be evenly distributed on the three phases of the circuit breaker, and the corresponding current phase difference is very small, which makes the current on the neutral line N very small. If the three-phase current difference increases, the neutral current will increase. Severe three-phase imbalance will cause the neutral line N to heat up severely, leading to electrical accidents. When the heating strip has a short circuit fault, the current in the phase where the heating strip is located will decrease, causing the current difference between the phases to increase. Therefore, we set the two parameters of current difference It is the rated working current value of a heating strip.

[0117] When the difference between the two phase currents on the same circuit breaker is less than the difference between the two currents When, such as: , or , or .

[0118] The logic control unit outputs an alarm corresponding to this circuit and disconnects the corresponding contactor. This allows detection and alarm of the heating strip circuit breaker fault location, eliminates electrical faults caused by three-phase imbalance, and improves the convenience of repair when the heating strip fails.

[0119] Figure 2 The connection diagram of the adaptive paver screed electric heating control system provided in this application is as follows: Figure 2 As shown in the figure, the adaptive paver screed electric heating control system provided by this embodiment is applied Figure 1 The adaptive paver screed electric heating control method described in the embodiment includes: The current monitoring unit is used to obtain the current values ​​of each phase at the upper ends of multiple circuit breakers in the electric heating control system in real time; a logic control unit connected to the current monitoring unit, the logic control unit being configured to calculate a sum of the single-phase currents based on the current values ​​of the phases; and compare the sum of the single-phase currents with a preset overload current value and a preset protection current value to perform current state determination; a control execution unit connected to the logic control unit, the control execution unit being configured to control all contactors to close to execute a full-power heating mode when the sum of all single-phase currents is less than the preset overload current value; to execute zoned alternating heating control according to a cumulative timing result when the sum of any single-phase current is greater than the preset overload current value and less than the preset protection current value, wherein the cumulative timing result is used to indicate the duration of the overload state; and to output an overload alarm signal and shut down the electric heating control system when the sum of any single-phase current is greater than the preset protection current value. A fault diagnosis unit is connected to the current monitoring unit and the logic control unit. The fault diagnosis unit is used to calculate the current difference between any two phases under the same circuit breaker based on the current values ​​of each phase for each circuit breaker; compare the current difference with a preset current difference value, and when the difference is greater than the preset current difference, output a fault alarm signal corresponding to the circuit breaker and disconnect the contactor corresponding to the circuit breaker.

[0120] Specifically, the current monitoring unit includes: Current transformer array, used to collect the instantaneous current values ​​of the U-phase, V-phase and W-phase at the upper end of each circuit breaker; A filtering module is connected to the current transformer array, and is used to filter the instantaneous value of the current and output a steady-state current value as the current value of each phase.

[0121] Specifically, the logic control unit includes: a sum calculation module, configured to respectively calculate the sum of the currents of the U phase, the V phase, and the W phase on the plurality of circuit breakers, and output the sum of the U phase current, the V phase current, and the W phase current; a comparison module connected to the sum calculation module, the comparison module being used to compare the sum of the U-phase current, the V-phase current and the W-phase current with a preset overload current value and a preset protection current value, respectively; A state identification generating module is connected to the comparison module, and is used to generate a current state identification according to the comparison result. The current state identification includes a normal identification, an overload identification or a protection identification.

[0122] During implementation, the adaptive paver screed electric heating control system provided by this embodiment specifically includes: 1. System overall structure and connection method The control system includes a current monitoring unit, a logic control unit, a control execution unit, and a fault diagnosis unit. Each unit is directly connected through an industrial standard physical interface: Current monitoring unit output → RS-485 communication cable → logic control unit input (transmits steady-state current value); Logic control unit output → digital I / O port → control execution unit input (transmission current state identifier); Current monitoring unit data bus → parallel data line → fault diagnosis unit input (shared steady-state current value); Fault diagnosis unit control line → control signal line → logic control unit reset port (sends reset command); The system power supply is uniformly supplied by a 24V DC regulated power supply, and all unit grounding wires are connected to a common grounding copper bus to ensure electrical safety.

[0123] 2. Detailed implementation of current monitoring unit The current monitoring unit includes a current transformer array and a filter module: 1. Current transformer array Physical Construction: 18 independent toroidal iron-core current transformers (silicon steel core, ±0.5% accuracy), grouped in groups of three, each corresponding to a circuit breaker (F1-F6). Installation: The U-phase current transformer clips onto the U-phase copper busbar at the top of the circuit breaker; the same applies to the V and W phases.

[0124] Function and effect: Directly collect instantaneous current value, output 0-5V analog signal (range 0-100A), and eliminate construction vibration interference.

[0125] Connection method: The secondary side output line of the current transformer is directly connected to the input end of the filter module through a shielded twisted pair cable.

[0126] 2. Filter module Hardware composition: A second-order low-pass filter circuit board built based on an operational amplifier with a cutoff frequency of 10Hz.

[0127] Processing logic: Adopt Butterworth low-pass filtering algorithm, input instantaneous current value, remove high-frequency noise, and output steady-state current value.

[0128] Function and effect: Ensure that the steady-state current value fluctuation range is ≤±0.2A, providing a stable data source for subsequent units.

[0129] Output interface: The output end of the filter module is connected to the logic control unit through the RS-485 interface chip (MAX485).

[0130] 3. Detailed implementation of the logic control unit The logic control unit includes a sum calculation module, a comparison module, and a status flag generation module, which are integrated into the PLC controller (the processor is ARM Cortex-M4): 1. Sum calculation module Processing logic: Using arithmetic accumulation algorithm, input the steady-state current value of 6 circuit breakers ( to ), accumulated independently phase by phase: U phase sum = .

[0131] The sum of phase V and phase W is calculated in the same way.

[0132] Function and effect: Output accuracy 0.1A, processing delay <1ms, ensuring real-time performance.

[0133] 2. Comparison Module 2.1 Parameter storage: Built-in EEPROM stores preset overload current value (e.g. 53A) and preset protection current value (e.g. 60A).

[0134] 2.2 Comparison Logic: Parallel execution of three-way threshold comparisons: Compare the U-phase total with the preset overload current value and the preset protection current value; The sum of phase V and phase W were compared independently at the same threshold.

[0135] 2.3 Function and Effect: Avoid three-phase interference and generate accurate status signals.

[0136] 3. Status identification generation module 3.1 Coding rules: Output 3-bit binary code based on the comparison result: Total of all phases < overload value → normal flag (0x01); The total of any phase is ≥ overload value and < protection value → overload flag (0x02); The total of any phase ≥ protection value → protection flag (0x03).

[0137] 3.2 Function and effect: Identify the output drive control execution unit, the response time is ≤ 2ms.

[0138] 4. Detailed implementation of the control execution unit The control execution unit is the relay driver circuit board: 1. Hardware: Six electromagnetic relays (contact capacity 30A), each corresponding to a contactor (KM1-KM6). The relay coil drive circuit is connected to the output port of the logic control unit through optocoupler isolation.

[0139] 2. Execution logic: 2.1 Receive normal flag (0x01): Close all relay contacts and attract KM1-KM6 contactors.

[0140] 2.2 Receive the overload flag (0x02): Start the timer to accumulate the overload duration; if the accumulated duration is less than the preset duration threshold (for example, 120 seconds), maintain full energization; if the accumulated duration is greater than or equal to the preset duration threshold, cyclically control the three groups of contactors: Group 1: energize KM1 / KM2 / KM4 and disconnect the rest; Group 2: energize KM1 / KM3 / KM5 and disconnect the rest; Group 3: energize KM2 / KM3 / KM4 / KM5 and disconnect the rest.

[0141] 2.3 Receive protection flag (0x03): disconnect all relays and trigger the sound and light alarm.

[0142] 3. Function and effect: Reduce peak power by 40% through group control to protect the generator.

[0143] 5. Detailed implementation of the fault diagnosis unit The fault diagnosis unit is implemented based on FPGA chip: 1. Input connection: Receives the steady-state current value of the current monitoring unit (synchronized with the logic control unit) via a parallel data bus.

[0144] 2. Diagnostic logic: 2.1 For each circuit breaker (F1-F6): Calculate the absolute value of the UV phase current difference, the absolute value of the VW phase current difference, and the absolute value of the WU phase current difference; If any difference is greater than a preset current difference (e.g., 5A), the corresponding heating strip is determined to be open circuited.

[0145] 2.2 Execution Action: Send Modbus RTU alarm frames to the HMI (for example, circuit breaker F1 fault frame: 01 06 00 01 EE CRC); Output low-level signal to disconnect the corresponding contactor (F1→KM1, F2→KM2, ..., F6→KM6); Send a hardware reset command to the logic control unit.

[0146] 3. Function and effect: Locate circuit breaker faults within 100ms, improving maintenance efficiency by 80%.

[0147] 6. Overall system operation effect 1. The current monitoring unit outputs a stable current value through the Butterworth filtering algorithm to eliminate field interference.

[0148] 2. The parallel comparison mechanism of the logic control unit ensures that the status flag is generated in real time, avoiding control delays.

[0149] 3. Grouped timing control of control execution units (such as KM1 / KM2 / KM4 combination) optimizes power distribution and extends generator life.

[0150] 4. The difference calculation logic of the fault diagnosis unit accurately locates the broken heating strip, reducing manual troubleshooting time.

[0151] All units work together through standardized interfaces (RS-485, digital I / O) to achieve fully automatic protection and fault handling of the paver screed heating system.

[0152] This application also provides an optional structure of an adaptive electric heating control system for a paver screed. Figure 3 The schematic diagram of the structure of the adaptive paver screed electric heating control system provided in this application is as follows: Figure 3 As shown, the present invention aims to adapt to the power requirements of various ironing boards while ensuring the safety and stability of the electric heating system through the joint work of the paver current monitoring unit, the insulation monitoring unit, and the logic control unit. According to the maximum power of the generator and the real-time current status of the electric heating system, the electric heating mode is switched, so that the electric heating system can fully output power and effectively protect the electric heating system when the power is insufficient.

[0153] At the same time, the present invention also provides a better diagnostic function, which allows operators or maintenance personnel to more easily find the fault point of the electric heating strip.

[0154] The electric heating system of the paver of the present invention is composed of a generator, an air breaker, a contactor, a control switch, a temperature sensor, a logic control unit, an insulation monitoring unit, an electric heating strip, and a current monitoring unit.

[0155] The generator is driven by the diesel engine transfer case belt and is the energy supply unit of the electric heating system.

[0156] The function of the circuit breaker, contactor and their wiring is to distribute electrical energy to each heating strip and provide short-circuit protection.

[0157] The electric heating system usually has five sets of circuit breakers and contactors, corresponding to the basic center and left screeds, the left extension, the right screed, and the right extension. The external wiring is evenly distributed according to the power of the screed electric heating strip.

[0158] The control switch is the command unit of the electric heating, which turns on or off the electric heating system, or switches between automatic and manual modes.

[0159] The temperature sensor is used to measure the temperature of the ironing plate and feed the temperature value back to the logic control unit in real time to control the state of the electric heating.

[0160] The logic control unit provides human-computer interaction, signal input and output, and logical operation processing. It controls the on / off switching of the contactors in the electric heating system based on input signals from the control switch and temperature sensor, thereby automatically controlling the operation of the electric heating system. The logic control unit also supports parameter setting and displays various information, such as real-time and set temperature information.

[0161] The insulation monitoring unit is used to detect the insulation resistance between the power line and the shielded ground wire PE, thereby detecting the insulation of the electric heating system and ensuring power safety.

[0162] The electric heating strip is the executive unit of the electric heating system. Electric heating strips of different lengths or powers are arranged according to the type and width of the ironing plate. The number of electric heating strips increases with the number of sections of the ironing plate.

[0163] The current monitoring unit monitors the electric heating system's current in real time. Depending on the current value, the system operates in different states, ensuring stable operation when used with different screed types and widths. This ensures maximum generator power is fully utilized while limiting the maximum operating current to protect the generator. Furthermore, when the power distribution of the heating strips is uniform, the unit displays the three-phase current value of each circuit breaker incoming line, allowing the location of any faulty heating strip to be determined by the uneven changes in the three-phase current.

[0164] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the present application that follow the general principles of the present application and include common knowledge or customary techniques in the art not disclosed herein. The description and examples are to be considered as exemplary only, and the true scope and spirit of the present application are indicated by the following claims.

[0165] It should be understood that the present application is not limited to the exact structure described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present application is limited only by the appended claims.

Claims

1. An adaptive paver screed electric heating control method, characterized in that: The method comprises: The current monitoring unit is used to obtain the current values ​​of each phase at the upper ends of multiple circuit breakers in the electric heating control system in real time; In the logic control unit, a sum of the single-phase currents is calculated based on the current values ​​of the phases, and the sum of the single-phase currents is compared with a preset overload current value and a preset protection current value to perform current state determination; When the sum of all the single-phase currents is less than the preset overload current value, all contactors are controlled to be closed to execute the full-power heating mode; When the sum of any of the single-phase currents is greater than the preset overload current value and less than the preset protection current value, performing zoned alternating heating control according to the accumulated timing result, wherein the accumulated timing result is used to indicate the duration of the state in which the sum of any of the single-phase currents is greater than the preset overload current value and less than the preset protection current value; When the sum of any of the single-phase currents is greater than the preset protection current value, an overload alarm signal is output and the electric heating control system is shut down; For each circuit breaker, the current difference between any two phases under the same circuit breaker is calculated based on the current values ​​of each phase, and the current difference is compared with the preset current difference value; when the current difference is greater than the preset current difference value, the fault alarm signal corresponding to the circuit breaker is output and the contactor corresponding to the circuit breaker is disconnected.

2. The adaptive paver screed electric heating control method according to claim 1, characterized in that: The method of obtaining the current values ​​of each phase of the upper ends of multiple circuit breakers in the electric heating control system in real time through the current monitoring unit includes: The instantaneous current values ​​of the U-phase, V-phase and W-phase at the upper end of each circuit breaker are collected through current transformers; The instantaneous current value is filtered to obtain a steady-state current value as the current value of each phase.

3. The adaptive paver screed electric heating control method according to claim 1, characterized in that: The logic control unit calculates the sum of the single-phase currents based on the phase current values, and compares the sum of the single-phase currents with a preset overload current value and a preset protection current value to perform current state determination, including: Calculate the sum of the currents of the U phase, the V phase, and the W phase on the multiple circuit breakers to obtain the sum of the U phase current, the V phase current, and the W phase current; respectively comparing the U-phase current sum, the V-phase current sum, and the W-phase current sum with the preset overload current value and the preset protection current value; A current state identifier is generated according to the comparison result, where the current state identifier includes a normal identifier, an overload identifier, or a protection identifier.

4. The adaptive paver screed electric heating control method according to claim 3, characterized in that: When the sum of all the single-phase currents is less than the preset overload current value, controlling all contactors to be attracted to execute the full-power heating mode includes: When the current state is marked as normal, a closing instruction is sent to all contactors; Monitor the contactor feedback signal. When all contactors are confirmed to be closed, maintain full power heating until the temperature reaches the preset value.

5. The adaptive paver screed electric heating control method according to claim 3, characterized in that: When the sum of any of the single-phase currents is greater than the preset overload current value and less than the preset protection current value, performing zoned alternating heating control according to the accumulated timing result includes: When the current status indicator is an overload indicator, the overload duration is started to accumulate time; If the accumulated time is less than the preset time threshold, all contactors are controlled to close; If the accumulated duration is greater than or equal to the preset duration threshold, the contactors are divided into three groups for cyclic execution: The first group: controls KM1, KM2, and KM4 contactors to close, and KM3 and KM5 to disconnect; The second group: control KM1, KM3, KM5 contactors to be closed, and KM2 and KM4 to be disconnected; The third group: controls KM2, KM3, KM4, and KM5 contactors to close and KM1 to disconnect; The duration of each group of attraction is equal to the preset alternating heating time.

6. The adaptive paver screed electric heating control method according to claim 3, characterized in that: When the sum of any of the single-phase currents is greater than the preset protection current value, an overload alarm signal is output and the electric heating control system is shut down, including: When the current state indicator is a protection indicator, the sound and light alarm is triggered to output the overload alarm signal; Send disconnect commands to all contactors synchronously and display the shutdown status on the human-machine interface.

7. The self-adaptive paver screed electric heating control method according to claim 1, characterized in that: For each circuit breaker, the current difference between any two phases under the same circuit breaker is calculated based on the current values ​​of each phase, and the current difference is compared with a preset current difference value; When the current difference is greater than the preset current difference, a fault alarm signal corresponding to the circuit breaker is output and a contactor corresponding to the circuit breaker is disconnected, including: For the current circuit breaker, calculate the absolute value of the UV phase current difference, the absolute value of the VW phase current difference, and the absolute value of the WU phase current difference respectively; When the absolute value of any current difference is greater than the preset current difference, it is determined that the heating strip corresponding to the current circuit breaker has a circuit breaker fault; Output a fault alarm signal including the circuit breaker number corresponding to the current circuit breaker, and disconnect the contactor uniquely corresponding to the current circuit breaker. After disconnecting the contactor corresponding to the current circuit breaker, re-execute the current state determination.

8. An adaptive paver screed electric heating control system, characterized in that: The system applies the adaptive paver screed electric heating control method according to any one of claims 1 to 7, and the system includes: The current monitoring unit is used to obtain the current values ​​of each phase at the upper ends of multiple circuit breakers in the electric heating control system in real time; a logic control unit connected to the current monitoring unit, the logic control unit being configured to calculate a sum of the single-phase currents based on the current values ​​of the phases; and compare the sum of the single-phase currents with a preset overload current value and a preset protection current value to perform current state determination; a control execution unit connected to the logic control unit, the control execution unit being configured to control all contactors to close to execute a full-power heating mode when the sum of all single-phase currents is less than the preset overload current value; to execute zoned alternating heating control according to a cumulative timing result when the sum of any single-phase current is greater than the preset overload current value and less than the preset protection current value, wherein the cumulative timing result is used to indicate the duration of the overload state; and to output an overload alarm signal and shut down the electric heating control system when the sum of any single-phase current is greater than the preset protection current value. A fault diagnosis unit is connected to the current monitoring unit and the logic control unit. The fault diagnosis unit is used to calculate the current difference between any two phases under the same circuit breaker based on the current values ​​of each phase for each circuit breaker; compare the current difference with a preset current difference value, and when the difference is greater than the preset current difference, output a fault alarm signal corresponding to the circuit breaker and disconnect the contactor corresponding to the circuit breaker.

9. The adaptive paver screed electric heating control system according to claim 8, characterized in that: The current monitoring unit includes: Current transformer array, used to collect the instantaneous current values ​​of the U-phase, V-phase and W-phase at the upper end of each circuit breaker; A filtering module is connected to the current transformer array, and is used to filter the instantaneous value of the current and output a steady-state current value as the current value of each phase.

10. The adaptive paver screed electric heating control system according to claim 8, characterized in that: The logic control unit includes: a sum calculation module, configured to respectively calculate the sum of the currents of the U phase, the V phase, and the W phase on the plurality of circuit breakers, and output the sum of the U phase current, the V phase current, and the W phase current; a comparison module connected to the sum calculation module, the comparison module being used to compare the sum of the U-phase current, the V-phase current and the W-phase current with a preset overload current value and a preset protection current value, respectively; A state identification generating module is connected to the comparison module, and is used to generate a current state identification according to the comparison result. The current state identification includes a normal identification, an overload identification or a protection identification.

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