Fault display system for four-wheel low-speed electric vehicle

Abstract

The invention relates to the technical field of electric vehicle electronic control systems, in particular to a four-wheel low-speed electric vehicle fault display system, which is based on CAN bus protocol construction, integrates high-precision total voltage acquisition and instrument man-machine interaction technologies, and innovatively defines a motor controller and instrument standardized fault code system. The technical problems of the four-wheel low-speed electric vehicle in the aspects of potential fault pre-judgment and fault rapid positioning are solved, specifically, when a motor is not in overcurrent, the flag bit at ID = 0 * 153 Byte1 Bit1 in a communication message is 0, when the motor is in an overcurrent continuous fault, the flag bit is 1, an instrument displays the motor overcurrent fault, a central control screen displays a motor phase line connection diagram, and fault phase lines flicker; maintenance personnel can conveniently and quickly know true causes of faults, formulate solution measures, maintain and eliminate the faults, and the maintenance efficiency is improved. Meanwhile, temperature compensation and fault early warning are linked in the system.

Description

Technical Field

[0001] The present invention relates to the technical field of electric vehicle electronic control systems, and in particular to a fault display system for four-wheel low-speed electric vehicles. Background Art

[0002] Four-wheel low-speed electric vehicles use electric energy as the driving energy source, and have the characteristics of low environmental pollution, convenience and fashion. With the continuous growth of the market holding of such vehicles, the functional requirements for four-wheel low-speed electric vehicles in the market are also gradually increasing. At present, the general faults when a four-wheel low-speed electric vehicle does not move are: motor overcurrent, phase line short circuit, abnormal Hall signal, stall protection, etc. When a fault occurs in the electric vehicle, the fault information displayed on the instrument is less, and the following problems specifically exist: 1. The traditional instrument does not realize the closed-loop display of "fault code - position - maintenance". For example, when the motor reports a "stall fault", the instrument only displays the code value, and the driver needs to spend more than 20 minutes to check for mechanical jamming or sensor abnormality; 2. The total voltage of the lead-acid battery used in four-wheel low-speed electric vehicles has temperature drift: the total voltage of the lead-acid battery fluctuates with the electrolyte temperature. In a -10°C environment, the total voltage of a 60V system may be falsely low by more than 5V, resulting in misjudgment of the SOC by the instrument; at the same time, the traditional solution does not introduce temperature compensation, and the accuracy rate of undervoltage alarm in winter is only 65%. Summary of the Invention

[0003] The purpose of the present invention is to provide a fault display system for four-wheel low-speed electric vehicles. This system is built based on the CAN bus protocol, integrates high-precision total voltage acquisition and instrument human-computer interaction technology, and innovatively defines a standardized fault code system for the motor controller and the instrument, solving the technical problems of potential fault prediction and rapid fault location of four-wheel low-speed electric vehicles.

[0004] In order to achieve the above purpose, the present invention adopts the following technical solutions: A fault display system for four-wheel low-speed electric vehicles, comprising: CAN network physical layer and node design, lead-acid battery intelligent monitoring module, Hall motor fault diagnosis system, and instrument fault visualization and fault code system; The CAN network physical layer and node design includes: Instrument node (IPK, ID = 0X110): As the bus master node, it is built-in with a 120Ω terminal resistor; the hardware integrates TVS surge protection (±50V), and the CAN_H / CAN_L pins meet the electrical standards; Motor controller node: The drive module (ID = 0X153) has a built-in 120Ω terminal resistor and is responsible for transmitting motor current, temperature, and fault codes 1 - 20; the communication module (ID = 0X253): has no terminal resistor and only transmits configuration parameters (such as baud rate, node address); the dual modules (drive module, communication module) are interconnected through an internal bus, and the fault isolation design ensures that the abnormal operation of the drive module does not affect the communication module; Bus parameters: Baud rate 500Kbps, sampling point at 50% of the cycle; The lead-acid battery intelligent monitoring module includes: Total voltage acquisition module: Adopts a high-precision monitoring chip (ADS1115) with a resolution of 12mV and a sampling period of 100ms; Temperature compensation module; Construction of the SOC (state of charge) estimation model; The Hall motor fault diagnosis system includes: Signal acquisition and processing: After the Hall signals (H1 / H2 / H3) are shaped, the chip (74HC14) captures the duty cycle (D) and the rising edge jitter (σ t ) of the channel; The phase current monitoring sensor has an accuracy of ±1%, a sampling frequency of 10kHz, and calculates the three-phase current imbalance rate (γ) in real time; Pre-fault algorithm: Stall prediction: When the rotational speed < 100rpm and γ > 20%, fault code 4 is triggered, and the motor power is limited to 50%; The instrument fault visualization and fault code system includes: Standardized definition of fault codes; Fault visualization.

[0005] Furthermore, in the temperature compensation module, the following compensation formula is adopted: U 标 = U 总 + 0.01×30× (T 壳 -25) (There are 30 single cells in total for 5 12V lead-acid batteries, the temperature coefficient is 0.01V / ℃ / single cell, and T shell is the battery surface temperature), U 标 is the compensated voltage value, and U 总 is the voltage value before compensation.

[0006] Furthermore, in the construction of the SOC estimation model: Through fitting 100 groups of charge and discharge data, a U 标 -SOC mapping table (error < ±3%) is established; for example: U ≥ 58.8 → SOC > 80% (green interval); 52.2V ≤ U < 58.8V → SOC 20% - 80% (yellow interval); U < 52.2V → SOC < 20% (red warning).

[0007] Furthermore, in the pre-fault algorithm: Hall element aging warning: When the channel duty cycle D deviates from 33% ± 5% and σ t > 20 μs and lasts for 5 minutes, a secondary fault code is triggered.

[0008] Furthermore, the fault visualization can be displayed through the instrument panel and the central control screen. The instrument panel includes: Fault information carousel: The current fault code is switched and displayed every 2 seconds. Tertiary faults are displayed first, in bold red font (e.g., phase line short circuit fault: Detected A / B phase resistance < 0.5 Ω, the instrument panel displays fault code 3); Fault status indicator: 4 lights correspond to the fault status. A primary fault is displayed in green, a secondary fault is displayed in orange, a tertiary fault is displayed in red, and a communication fault is displayed in blue. The indicator lights flash quickly (2 Hz) during a fault.

[0009] Furthermore, the central control screen includes: Clicking on the fault code pops up three layers of information: Basic information: Code value, level, trigger time; Real-time data: Related waveforms (e.g., phase line short circuit fault: Detected A / B phase resistance < 0.5 Ω, the central control screen displays the motor phase line connection diagram, and the faulty phase line flashes); Maintenance guidelines: Graphic steps (e.g., "Check the motor phase line connection" "Replace the motor").

[0010] The fault code processing flow of a four-wheel low-speed electric vehicle fault display system is as follows: S1. Signal detection: The motor controller detects abnormal A-phase current (lasting for 500 ms), triggering an overcurrent interruption; S2. CAN communication: The drive module sends a fault frame through ID = 0X153. The data includes: Byte2 = 0x01 (fault code), Byte5 = 0x01 (primary fault); S3. Instrument response: The red light on the left screen flashes, displaying "01" motor overcurrent fault; The right screen automatically switches to the motor interface, the A-phase waveform area is marked in red, and a prompt "Stop immediately and check the motor load" pops up; S4. Control closed-loop: The instrument sends an instruction frame (Byte2 = 0x01) through ID = 0X110. After receiving it, the motor controller limits the PWM duty cycle to 50% to avoid device burnout; S5. Data storage: Information such as the fault time, current vehicle speed (25 km / h), battery SOC (35%) is stored in the ROM to support subsequent fault tracing.

[0011] The beneficial effects of the present invention are as follows: A fault display system for four-wheel low-speed electric vehicles provided by the present invention is constructed based on the CAN bus protocol, integrating high-precision total voltage acquisition and instrument human-computer interaction technology, and innovatively defining a standardized fault code system for motor controllers and instruments, solving the technical problems of potential fault prediction and rapid fault location for four-wheel low-speed electric vehicles. Specifically, when the motor is not overcurrent, the flag bit at ID = 0X153 Byte1 Bit1 in the communication message is 0; when the motor has a continuous overcurrent fault, the flag bit is 1, and the instrument displays the motor overcurrent fault, and the central control screen displays the motor phase connection diagram, and the faulty phase line flashes; it is convenient for maintenance personnel to quickly understand the true cause of the fault, formulate solutions, repair and eliminate the fault, improving the maintenance efficiency; at the same time, temperature compensation and fault warning are linked in this system: when the battery pack T shell = 56 °C (exceeding the threshold of 55 °C), the instrument can calculate the compensated voltage and trigger a fault code, and the display screen displays the battery over-temperature diagram, orange is displayed at 55 °C-75 °C, and red is displayed at 75 °C; if the T shell continues to rise to 75 °C, it is upgraded to a first-level fault, and the instrument sends a load reduction signal to the controller through communication, and the controller can only drive at a speed lower than 5 km / h. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 FIG. is a schematic diagram of the CAN communication topology structure of the fault display system for four-wheel low-speed electric vehicles of the invention; Figure 2 FIG. is a schematic diagram of the circuit connection of the fault display system for four-wheel low-speed electric vehicles of the invention; The reference numbers in the figure are: 1, instrument; 2, controller; 3, drive motor; 4, accelerator pedal; 5, battery pack. DETAILED DESCRIPTION OF THE INVENTION

[0013] Specific Embodiment 1: The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention. It should be noted that: in the present invention, if there is no special description, all the implementation manners and preferred implementation methods mentioned herein can be combined with each other to form a new technical solution. In the present invention, if there is no special description, all the technical features and preferred features mentioned herein can be combined with each other to form a new technical solution. The "range" disclosed in the present invention can be in the form of one or more lower limits and one or more upper limits.

[0014] As shown in the specification appendix Figure 1As shown, to solve the problem that existing traditional instruments do not achieve the closed-loop display of "fault code - position - maintenance", do not introduce temperature compensation, and the instrument is prone to misjudging the SOC, the present invention designs and provides a fault display system for four-wheel low-speed electric vehicles, which system includes: CAN network physical layer and node design, lead-acid battery intelligent monitoring module, Hall motor fault diagnosis system, and instrument fault visualization and fault code system; As shown in the specification appendix Figure 1 As shown, the CAN network physical layer and node design system adopts a dual-terminal resistor redundant architecture to ensure bus stability, and specifically includes the following: Instrument node (IPK, ID = 0X110), as the bus master node, with a built-in 120Ω terminal resistor; the hardware integrates TVS surge protection (±50V), and the CAN_H / CAN_L pins meet the ISO 11898-2 electrical standard; Motor controller node: drive module (ID = 0X153), with a built-in 120Ω terminal resistor, responsible for transmitting motor current, temperature, and fault codes 1-20; communication module (ID = 0X253): without a terminal resistor, only transmits configuration parameters (such as baud rate, node address); the two modules are interconnected through an internal bus, and the fault isolation design ensures that the abnormal situation of the drive module does not affect the communication module; Bus parameters: baud rate 500Kbps, sampling point at 50% of the cycle; The lead-acid battery intelligent monitoring module includes the following: Total voltage acquisition scheme: adopt a high-precision monitoring chip (ADS1115), with a resolution of 12mV and a sampling period of 100ms; Temperature compensation formula: U 标 = U 总 + 0.01×30× (T 壳 - 25) (There are 30 single cells in total for 5 12v lead-acid batteries, temperature coefficient 0.01V / ℃ / single cell, T shell is the battery surface temperature); U 标 is the compensated voltage value, U 总 is the voltage value before compensation; SOC estimation model: through fitting 100 groups of charge and discharge data, establish a U 标 -SOC mapping table (error < ±3%). For example: U≥58.8 → SOC>80% (green interval); 52.2V≤U<58.8V → SOC 20%-80% (yellow interval); U<52.2V → SOC<20% (red warning); as shown in the following table:

[0015] The Hall motor fault diagnosis system includes the following: Signal acquisition and processing: After the Hall signals (H1 / H2 / H3) are shaped, the chip (74HC14) captures the duty cycle (D) and the rising edge jitter (σ t ) The phase current monitoring sensor has an accuracy of ±1%, a sampling frequency of 10 kHz, and calculates the three-phase current imbalance rate (γ) in real time; Pre-fault algorithm: Hall element aging warning: When D deviates from 33% ± 5% and σ t > 20 μs and lasts for 5 minutes, the secondary fault code 8 is triggered; Locked-rotor prediction: When the rotational speed < 100 rpm and γ > 20%, the fault code 4 is triggered, and the motor power is limited to 50%; The instrument fault visualization and fault code system includes the following: Standardized definition of fault codes:

[0016] Fault visualization: Interactive design innovation Instrument screen (left screen, 7 inches): Fault information carousel: The current fault code is switched and displayed every 2 seconds. Tertiary faults are displayed first, in bold red font (e.g., phase line short circuit fault: detected A / B phase resistance < 0.5 Ω, the instrument displays fault code 3); Fault status indicator lights: 4 lights correspond to the fault status. The primary fault is displayed in green, the secondary fault is displayed in orange, the tertiary fault is displayed in red, and the communication fault is displayed in blue. The indicator lights flash quickly (2 Hz) during a fault; Central control screen (right screen, 7 inches): Clicking on the fault code pops up three layers of information: 1. Basic information: code value, level, trigger time; 2. Real-time data: relevant waveforms (e.g., phase line short circuit fault: detected A / B phase resistance < 0.5 Ω, the central control screen displays the motor phase line connection diagram, and the faulty phase line flashes); 3. Maintenance guidelines: graphic steps (such as "Check the motor phase line connection" "Replace the motor").

[0017] Furthermore, as shown in the instruction manual appendix Figure 2As shown in the figure, this is the circuit connection diagram of the fault display system for a four-wheel low-speed electric vehicle. The instrument 1 is connected to the controller 2 through a communication line. The controller 2 is connected to the drive motor 3 and the accelerator pedal 4. The instrument 1 is connected to the temperature sensor of the battery pack through a hard wire. The controller 2 sends communication messages through the CAN communication line. The instrument 1 collects and analyzes the communication messages of the controller 2, and the instrument 1 displays the fault information sent by the controller 2. The fault information includes: motor overcurrent, accelerator pedal fault, Hall fault, controller fault, phase wire short circuit, battery over-temperature and other faults; when the motor is not overcurrent, the flag bit at ID = 0X153 Byte1 Bit1 in the communication message is 0. When the motor overcurrent persists, the flag bit is 1. The instrument displays the motor overcurrent fault, and the central control screen displays the motor phase wire connection diagram, and the faulty phase wire flashes, so as to facilitate maintenance personnel to quickly understand the true cause of the fault, formulate solutions, repair and eliminate the fault, and improve the maintenance efficiency.

[0018] Further, the full process example of the fault code processing of the fault display system for the four-wheel low-speed electric vehicle of the present invention is as follows: S1. Signal detection: The motor controller detects that the current of phase A is abnormal (lasting for 500 ms), and triggers an overcurrent interrupt; S2. CAN communication: The drive module sends a fault frame through ID = 0X153, and the data includes: Byte2 = 0x01 (fault code), Byte5 = 0x01 (primary fault); S3. Instrument response: The red light on the left screen flashes, displaying "01" motor overcurrent fault; the right screen automatically switches to the motor interface, the waveform area of phase A is marked red, and a prompt "Stop immediately to check the motor load" pops up; S4. Control closed-loop: The instrument sends an instruction frame (Byte2 = 0x01) through ID = 0X110. After receiving it, the motor controller limits the PWM duty cycle to 50% to avoid device burnout; S5. Data storage: Information such as the fault time, current vehicle speed (25 km / h), and battery SOC (35%) is stored in the ROM to support subsequent fault tracing; Temperature compensation and fault warning linkage: When the T shell of the battery pack = 56 °C (exceeding the threshold of 55 °C), the instrument performs the following operations. Calculate the compensated voltage: U 标 = 54V + 0.01×30×(46 - 25) = 60.3V, and the SOC display is corrected from 28% to 35%; trigger fault code 23, and the right screen displays the battery over-temperature diagram. Orange is displayed at 55 °C - 75 °C, and red is displayed at 75 °C; if the T shell continues to rise to 75 °C, it is upgraded to a primary fault, and the instrument sends a load reduction signal to the controller through communication, and the controller can only drive at a speed lower than 5 km / h.

[0019] The above are only the preferred embodiments of the present invention, and do not impose any form of limitation on the present invention. Although the present invention has been disclosed above with the preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to equivalent embodiments by using the technical content disclosed above within the scope of the technical solution of the present invention. However, as long as it does not depart from the content of the technical solution of the present invention, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A fault display system for a four-wheel low-speed electric vehicle, characterized in that, Including CAN network physical layer and node design, lead-acid battery intelligent monitoring module, Hall motor fault diagnosis system, and instrument fault visualization and fault code system; The CAN network physical layer and node design includes: Instrument node (IPK, ID = 0X110): As the bus master node, with a built-in 120Ω terminal resistor; hardware integrated with TVS surge protection (±50V), and the CAN_H / CAN_L pins meet the ISO 11898-2 electrical standard; Motor controller node: Drive module (ID = 0X153), with a built-in 120Ω terminal resistor, responsible for transmitting motor current, temperature, and fault codes 1-20; Communication module (ID = 0X253): Without a terminal resistor, only transmits configuration parameters (such as baud rate, node address); The drive module and communication module are interconnected through an internal bus, and the fault isolation design ensures that the abnormal drive module does not affect the communication module; Bus parameters: Baud rate 500Kbps, sampling point at 50% of the cycle; The lead-acid battery intelligent monitoring module includes: Total voltage acquisition module: Adopts a high-precision monitoring chip (ADS1115), with a resolution of 12mV and a sampling period of 100ms; Temperature compensation module; SOC estimation model construction; The Hall motor fault diagnosis system includes: Signal acquisition and processing: After the Hall signals (H1 / H2 / H3) are shaped, the chip (74HC14) captures the duty cycle (D) and the rising edge jitter (σ t ) of the channel; Phase current monitoring sensor with an accuracy of ±1%, sampling frequency 10kHz, and real-time calculation of the three-phase current imbalance rate (γ); Pre-fault algorithm: Stall prediction: When the speed < 100rpm and γ > 20%, trigger fault code 4 and limit the motor power to 50%; The instrument fault visualization and fault code system includes: Standardized definition of fault codes; Fault visualization.

2. The fault display system for a four-wheel low-speed electric vehicle according to claim 1, characterized in that In the temperature compensation module, the following compensation formula is adopted: U 标 = U 总 + 0.01 × 30 × (T 壳 - 25) (There are 30 single cells in total for 5 12V lead-acid batteries, the temperature coefficient is 0.01V / ℃ / single cell, and T shell is the battery surface temperature) U 标 is the voltage value after compensation, and U 总 is the voltage value before compensation.

3. The fault display system for a four-wheel low-speed electric vehicle according to claim 1, wherein In the construction of the SOC estimation model: Through fitting 100 groups of charge and discharge data, establish the U 标 -SOC mapping table (error < ±3%); For example: U ≥ 58.8 → SOC > 80% (green interval); 52.2V ≤ U < 58.8V → SOC 20% - 80% (yellow interval); U < 52.2V → SOC < 20% (red warning).

4. A four-wheel low-speed electric vehicle fault display system according to claim 1, wherein, In the pre-fault algorithm: Hall element aging warning: When D deviates from 33% ± 5% and σ t > 20 μs, a secondary fault code is triggered after 5 minutes of duration.

5. The fault display system for a four-wheel low-speed electric vehicle according to claim 1, characterized in that, The fault visualization can be displayed through the instrument screen and the central control screen. The instrument screen includes: Fault information carousel: Switch and display the current fault code every 2 seconds, with priority display for level-three faults in bold red font (such as phase line short-circuit fault: detected A / B phase resistance < 0.5Ω, the instrument displays fault code 3); Fault status indicator: 4 lights corresponding to the fault status, green for level-one faults, orange for level-two faults, red for level-three faults, and blue for communication faults. The indicator flashes quickly (2Hz) during faults.

6. The fault display system of a four-wheel low-speed electric vehicle according to claim 5, characterized in that, The central control screen includes: Clicking on the fault code pops up three layers of information: Basic information: Code value, level, trigger time; Real-time data: Related waveforms (such as phase line short-circuit fault: detected A / B phase resistance < 0.5Ω, the central control screen displays the motor phase line connection diagram, and the faulty phase line flashes); Maintenance guidelines: Graphic steps (such as "Check the motor phase line connection" and "Replace the motor").

7. A four-wheel low-speed electric vehicle fault display system according to claim 1, characterized in that, The fault code processing flow is as follows: S1. Signal detection: The motor controller detects abnormal A-phase current (lasting 500ms) and triggers an overcurrent interrupt; S2. CAN communication: The drive module sends a fault frame through ID = 0X153, and the data includes: Byte2 = 0x01 (fault code), Byte5 = 0x01 (level-one fault); S3. Instrument Response: The red light on the left screen flashes, displaying the "01" motor overcurrent fault; the right screen automatically switches to the motor interface, the A-phase waveform area is marked in red, and a prompt "Stop immediately to check the motor load" pops up; S4. Control Closed-loop: The instrument sends an instruction frame (Byte2 = 0x01) through ID = 0X110. After receiving it, the motor controller limits the PWM duty cycle to 50% to avoid device burnout; S5. Data Storage: Information such as the fault time, current vehicle speed (25 km / h), battery SOC (35%), etc. is stored in the ROM to support subsequent fault tracing.

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