A safety control method for electric drive controllers

Abstract

This invention discloses a safety control method for an electric drive controller of an electric tricycle. The method includes: establishing and storing torque-speed-maximum duration characteristic data; identifying driver intent by acquiring throttle signals via AD converter and establishing torque demand; determining the maximum duration based on the difference between real-time speed and torque demand; dynamically adjusting torque output, automatically reducing to rated torque after the time limit under stable operating conditions, and re-identifying intent under sudden changes in operating conditions. This invention requires no complex model, has simple control logic, and can be independently verified by vehicle manufacturers, effectively improving the operational safety and reliability of the electric drive controller.

Description

Technical Field

[0001] This invention belongs to the field of electric tricycle controller technology, specifically referring to a safety control method for an electric drive controller. Background Technology

[0002] As an important tool for short-distance transportation and daily travel, the operational safety of the electric drive controller of electric tricycles directly affects the reliability of the entire vehicle. Current temperature protection schemes for electric drive controllers of electric tricycles mainly adopt a strategy combining graded threshold protection and active intervention: graded threshold protection executes protection actions such as power-off and current limiting according to the temperature gradient, balancing safety and operational continuity; active intervention relies on MOSFET loss models and thermal circuit models, combined with real-time current and voltage data to calculate device junction temperatures, predict risks in advance, and reduce load; simultaneously, it monitors accumulated heat through the square integral of the output current to adapt to extreme conditions such as stall and overload; some schemes also use algorithms such as LSTM to predict the temperature rise in the next 5 minutes and adjust the heat dissipation strategy in advance.

[0003] However, the aforementioned existing technologies have significant drawbacks: on the one hand, they require monitoring multi-dimensional data such as current, voltage, and temperature, and the data acquisition link is complex and susceptible to interference; on the other hand, they rely on complex mathematical models such as loss models and thermal circuit models, making model parameter calibration difficult and model accuracy difficult to guarantee under different operating conditions, which makes it impossible to effectively verify the accuracy and reliability of temperature protection, thereby affecting the overall vehicle operation stability and increasing after-sales maintenance costs. Summary of the Invention

[0004] This invention provides a safety control method for electric drive controllers, proposing a safety control method that does not rely on complex models and multi-dimensional data monitoring. This method simplifies control logic, reduces verification difficulty, and improves the operational safety and reliability of electric drive controllers.

[0005] To achieve the above objectives, the present invention provides a safety control method for an electric drive controller, comprising the following steps: Step 1: Establish and store torque-speed-maximum duration characteristic data: Install the motor controller on the test bench, refer to the MAP diagram of the motor controller, and test the maximum duration of stable operation for multiple different torque values ​​from rated torque to maximum torque under different speed conditions. Organize the test results into a two-dimensional data table and store it. The horizontal axis of the two-dimensional data table is the motor speed, the vertical axis is the torque, and the data at the intersection of the horizontal axis and the vertical axis is the maximum sustainable working time under the corresponding speed and torque combination. Step 2: Identify driver intent to establish torque demand information: Acquire throttle analog signals through AD analog-to-digital conversion, analyze the acquired signals in combination with the working boundary conditions and changing characteristics of the throttle, and convert them into torque demand corresponding to throttle operation; Step 3: Determine the maximum duration of the current torque: Based on the torque demand value obtained in Step 2 and the real-time monitored motor speed, search the two-dimensional data table stored in Step 1. If both the torque demand value and the motor speed fall between the discrete data points in the two-dimensional data table, the maximum continuous working time under the current speed and torque demand combination is calculated by the difference. Step 4: Dynamically adjust torque output: Calculate the average value of the torque demand value. If the cumulative change in the torque demand value is less than 20%, maintain the current torque setpoint as the torque demand value until the working time exceeds the maximum duration determined in Step 3, then reduce the torque to the rated torque. If the cumulative change in the torque demand value is greater than 20%, return to Step 2 to re-identify the driver's intention and establish new torque demand information, and enter the next control cycle.

[0006] As a further aspect of the present invention: the speed interval of the two-dimensional data table in step one is 100 rpm, the torque interval is 1 / 10 of the maximum torque, and the minimum torque is the minimum torque at which the motor controller can operate stably and continuously.

[0007] As a further aspect of the present invention: the specific method for calculating the difference in step three is as follows: assuming the current driver's intended torque NM is between NM... n and NM n+1 Between, the current speed RPM is between RPM n and RPM n+1 Between, Tn is the rotational speed in RPM. n Torque NM n The maximum duration of time, T n+1 Rotational speed (RPM) n Torque NM n+1 The maximum duration of time, T n+2 Rotational speed (RPM) n+1 Torque NM n+1 The maximum duration of time, T n+3 Rotational speed (RPM) n+1 Torque NM n The maximum duration of time is calculated as follows: 1) Calculate the speed correction coefficient K1=(T n+3 - T n ) / (RPM n+1 - RPM n ), to obtain the torque NM corresponding to the rotational speed RPM. n The correction duration Trpm n =T n *(1+(RPM-RPM n )*K1); 2) Calculate the speed correction coefficient K2=(Tn+2 - T n+1 ) / (RPM n+1 - RPM n ), to obtain the torque NM corresponding to the rotational speed RPM. n+1 The correction duration Trpm n+1 =T n+1 *(1+(RPM-RPM n )*K2); 3) Calculate the torque correction coefficient K3 = (Trpm) n+1 - Trpm n ) / (NM n+1 - NM n ), thus obtaining the maximum duration T = Trpm under the current torque demand NM and speed RPM combination. n *(1+K3*(NM-NM n )).

[0008] As a further aspect of the present invention: the criterion for determining the maximum duration of stable operation in step one is that the temperature rise of the motor controller does not exceed its rated maximum operating temperature, and all electrical performance parameters remain within the preset allowable range.

[0009] As a further aspect of the present invention: Step two, in combination with the working boundary conditions and changing characteristics of the throttle, specifically involves filtering and validating the collected throttle analog signal based on the maximum stroke, minimum stroke, response delay time, and signal fluctuation threshold of the throttle, removing abnormal signals, and then converting it into torque demand.

[0010] As a further aspect of the present invention: the calculation method for the cumulative change of torque demand value in step four is as follows: taking a preset time window as the statistical period, calculate the difference between the maximum and minimum torque demand values ​​within the period, and then compare it with the average torque demand value within the period.

[0011] As a further aspect of the present invention: the electric drive controller is applied to the field of electric tricycles, and the test bench is a performance test bench for electric tricycle-specific motor controllers.

[0012] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. Simple and reliable control logic: It does not rely on complex mathematical models such as MOSFET loss models and thermal circuit models, nor does it require monitoring multi-dimensional data. Safety control can be achieved solely through measured torque-speed-maximum duration characteristic data and throttle signals, which reduces the complexity of control logic and the difficulty of verification. OEMs can complete data acquisition and solution verification by independently building test benches, reducing their technical dependence on suppliers.

[0013] 2. Precise Torque Adjustment: The maximum continuous working time under different operating conditions is accurately obtained through the difference calculation method. Combined with the dynamic recognition of the driver's intention, the torque output is precisely adjusted to meet the driving power requirements and strictly control the continuous torque output time, effectively avoiding overheating and damage to the electric drive controller and extending its service life.

[0014] 3. High adaptability: By flexibly setting the speed interval, torque interval and signal processing parameters of the two-dimensional data table, it can be adapted to electric drive controllers of different models and power levels of electric tricycles. It has a wide range of applications and is easy to modify and adjust without reconstructing the control logic.

[0015] 4. High operational stability: Through signal filtering, validity verification, and fault prediction, the anti-interference capability of data acquisition and control logic is improved, the impact of abnormal operating conditions on control effect is reduced, the stable operation of electric tricycles is ensured, and after-sales maintenance costs are reduced. Attached Figure Description

[0016] Figure 1 This is a flowchart of the method of the present invention. Detailed Implementation

[0017] The safety control method of the present invention will be described in detail below with reference to specific technical details.

[0018] like Figure 1 As shown, a safety control method for an electric drive controller includes the following steps: 1) Establish and store torque-speed-maximum duration characteristic data; The core of this step is to obtain stable operating boundary data of the electric drive controller under different operating conditions through actual measurements, so as to provide a basis for subsequent control. The specific implementation process is as follows: Test preparation: Select an electric drive controller that matches the actual model installed in the electric tricycle and fix it on a special motor controller performance test bench for electric tricycles. The test bench should have functions such as speed adjustment, torque loading, temperature monitoring, and data recording. The ambient temperature should be controlled at 25±5℃ to avoid interference from ambient temperature on the test results.

[0019] Test standards and parameter settings: Refer to the MAP (torque-speed-efficiency characteristic diagram) of the electric drive controller to determine the test speed range and torque range. The speed range should cover the commonly used speed range of actual electric tricycle operation (e.g., 0-3000 rpm), and the speed interval should be set to 100 rpm, meaning the test speed points should cover the RPM range. n RPM n+1 RPM n+2 ... (RPM) n+1 =RPMn +100rpm); the torque range starts from the minimum torque at which the controller can operate stably and continuously, and ends at the controller's rated maximum torque. The torque interval is set to 1 / 10 of the maximum torque, meaning the torque test points include Nm. n NM n+1 NM n+2 ... (NM) n+1 =NM n +Maximum torque × 1 / 10).

[0020] Operating Condition Testing and Data Recording: For each speed-torque combination (RPMi, NMj), a stable operating test was conducted on the test bench. During the test, the temperature rise of the core components of the electric drive controller (such as IGBT modules, capacitors, etc.), input and output voltages, current, and other electrical performance parameters were monitored in real time. When one of the following two conditions was met, the test was stopped and the continuous operating time under the current condition was recorded. This time is the maximum duration Tn under that speed-torque combination: (1) The temperature rise of the core components of the electric drive controller reaches its rated maximum operating temperature, such as the temperature rise of the IGBT module reaching 125℃; (2) The electrical performance parameters of the electric drive controller exceed the preset allowable range, such as output voltage fluctuation exceeding ±5% and current distortion rate exceeding 10%.

[0021] Data Processing and Storage: All obtained speed-torque-maximum duration data are processed into a two-dimensional data table. The horizontal axis of this table represents motor speed (rpm), and the vertical axis represents torque (N·m). The intersection of the horizontal and vertical axes represents the maximum continuous operating time (s) for the corresponding speed and torque combination. This two-dimensional data table is stored in a non-volatile storage device of the electric drive controller, such as an EEPROM, to ensure data integrity after power failure, allowing for real-time retrieval by subsequent control logic.

[0022] 2) Identify driver intent and establish torque demand information; This step involves collecting and analyzing throttle signals to accurately obtain the driver's driving intentions and translate them into specific torque requirements. The specific implementation process is as follows: Signal acquisition: The analog signal output from the accelerator pedal, such as a 0-5V voltage signal, is acquired through the built-in AD (analog-to-digital converter) module of the electric drive controller. The acquisition frequency is set to 100Hz to ensure the real-time performance of the signal acquisition.

[0023] Signal Analysis and Validity Verification: The acquired analog throttle signal is preprocessed based on the throttle's operating boundary conditions and variation characteristics. The throttle's operating boundary conditions include the maximum signal value corresponding to the maximum travel (e.g., 5V), the minimum signal value corresponding to the minimum travel (e.g., 0V), and a response delay time ≤ 10ms. Variation characteristics include a signal fluctuation threshold ≤ ±0.05V. The preprocessing process specifically includes: (1) Filtering: The moving average filtering algorithm is used to take the average of the five consecutive signal values ​​collected and remove high-frequency interference signals; (2) Validity verification: Determine whether the filtered signal value is within the effective range of 0-5V and whether the signal fluctuation is less than the set threshold. If it exceeds the range or the fluctuation is too large, it is determined to be an abnormal signal and the effective signal value of the previous cycle is used. If the signal is abnormal for three consecutive cycles, a fault prompt is output and the torque output is limited.

[0024] Torque Demand Conversion: Based on a preset throttle signal-torque mapping relationship, the validated analog throttle signal is converted into a corresponding torque demand value. This mapping relationship is set based on the power performance requirements of the electric tricycle. For example: when the throttle signal is 0V, the torque demand value is 0 N·m; when the throttle signal is 2.5V, the torque demand value is 50% of the rated torque; when the throttle signal is 5V, the torque demand value is the rated maximum torque. Through this mapping relationship, the driver's acceleration, constant speed, and deceleration intentions are accurately identified, and the required torque output of the vehicle is determined.

[0025] 3) Determine the maximum duration of the current torque; This step, based on the current torque requirement and motor speed, retrieves and calculates the corresponding maximum continuous working time from a preset two-dimensional data table. The specific implementation process is as follows: Real-time parameter acquisition: The actual current speed of the motor (unit: rpm) is acquired in real time through the speed detection module of the electric drive controller, such as a Hall sensor; at the same time, the effective torque demand value (unit: N·m) obtained in step 2 is extracted.

[0026] Data table retrieval: The obtained actual motor speed and torque requirements are matched against a two-dimensional data table stored in a non-volatile storage device to determine whether the current parameter combination falls on a discrete data point in the two-dimensional data table. (1) If the actual speed of the motor is equal to a certain discrete speed point, such as RPMn, and the torque demand value is equal to a certain discrete torque point corresponding to that speed point, such as NMn, then the maximum duration Tn corresponding to the intersection point is directly read as the maximum continuous working time of the current working condition. (2) If the actual speed and / or torque demand of the motor falls between discrete data points, such as the speed RPM being between RPM nand RPM n+1 Between, torque NM is between NM n and NM n+1 Between these, the maximum continuous working time is accurately derived using the difference calculation method.

[0027] The specific process of difference calculation: Let the current actual motor speed be RPM and the torque requirement be NM, where RPM n <RPM<RPM n+1 NM n <NM<NM n+1 In the two-dimensional data table, the rotational speed (RPM) n Torque (NM) n The corresponding maximum duration is T n Rotational speed (RPM) n Torque (NM) n+1 The corresponding maximum duration is T n+1 Rotational speed (RPM) n+1 Torque (NM) n The corresponding maximum duration is T n+3 Rotational speed (RPM) n+1 Torque (NM) n+1 The corresponding maximum duration is T n+2 The difference calculation includes the following three steps: (1) Calculate the speed correction coefficient K1 and the torque NM corresponding to the speed RPM. n The correction duration Trpm n : K1=(T n+3 - T n ) / (RPM n+1 - RPM n ); Trpm n =T n *(1+(RPM-RPM n )K1); (2) Calculate the speed correction coefficient K2 and the torque NM corresponding to the speed RPM. n+1 The correction duration Trpm n+1 : K2=(T n+2 - T n+1 ) / (RPM n+1 - RPM n ); Trpm n+1 =T n+1 (1+(RPM-RPM n )K2); (3) Calculate the torque correction coefficient K3 and the maximum duration T of the current operating condition: K3=(Trpm n+1 - Trpm n ) / (NM n+1 - NM n ); T=Trpm n (1+K3*(NM-NM n )); By calculating the difference as described above, we can ensure that even if the current operating condition is not directly recorded in the two-dimensional data table, we can accurately obtain the corresponding maximum continuous working time, thus ensuring the continuity and accuracy of the control logic.

[0028] 4) Dynamically adjust torque output; This step dynamically adjusts the torque output of the electric drive controller based on changes in torque demand and the maximum continuous working time under the current operating conditions. The specific implementation process is as follows: Torque demand variation calculation: Set a preset time window, such as 1 second, as the statistical period. Within each statistical period, calculate the average, maximum, and minimum torque demand values. The cumulative variation in torque demand is calculated as follows: Cumulative torque change rate = (maximum value - minimum value) / average value × 100%; This calculation method can accurately determine whether the driver's intention has changed significantly, such as from constant speed to rapid acceleration.

[0029] Torque output adjustment logic: (1) If the cumulative torque change rate is less than 20%, it is determined that the driver's intention is stable (such as driving at a constant speed or accelerating slowly). Then, the current torque is maintained at the average torque demand within the statistical period, and the torque is continuously output. At the same time, a timer is started to record the continuous output time of the current torque. When the continuous output time exceeds the maximum continuous working time T determined in step 3, the torque output is automatically reduced to the rated torque until the driver adjusts the throttle, causing the cumulative torque demand change rate to exceed 20%, or the continuous output time is lower than T, and then the torque is restored to the original torque demand value. (2) If the cumulative rate of change of torque is greater than 20%, it is determined that the driver’s intention has changed significantly, such as rapid acceleration or deceleration. Then, the current torque output timing is stopped immediately, and the process returns to step 2) to re-acquire the throttle signal, identify the driver’s intention, and establish new torque demand information to enter the next control cycle, ensuring that the torque output matches the driver’s intention in real time.

[0030] Through the above dynamic adjustment logic, the stability of torque output during normal driving is ensured, and a rapid response is made when the driver's intention changes. At the same time, the overheating and damage of the electric drive controller caused by the torque continuously exceeding the maximum duration is avoided. Example

[0031] Test subject: A dedicated electric drive controller for electric tricycles was selected. The motor model is 140YC7250403NA, and the controller model is YCK072090D. Its rated voltage is 72V, rated power is 1500W, rated torque is 3N·m, maximum torque is 60N·m, and the maximum operating temperature of the core component MOS module is 125℃. It is suitable for electric tricycles with a load capacity of 1.0-1.5 tons.

[0032] Test Equipment and Environment: Test equipment: Dedicated test bench for electric tricycle motor controller (model: GZDL500AF), supporting continuous speed adjustment from 0-8000rpm, precise torque loading from 0-500N·m, and temperature measurement accuracy ±0.5℃; AD signal acquisition module (sampling frequency 100Hz, resolution 12-bit); non-volatile storage device (EEPROM model: AT24C64, storage capacity 64Kbit); data logger (supports synchronous recording of parameters such as speed, torque, temperature, and time, with a recording interval of 100ms).

[0033] Test environment: ambient temperature 25℃±2℃, relative humidity 45%-55%, no electromagnetic interference, grounding resistance of test bench ≤4Ω, meeting the test environment requirements specified in GB / T18488.1-2015 "Motors and controllers for electric vehicles Part 1: Technical conditions".

[0034] The implementation process is as follows: 1) Establishment and storage of torque-speed-maximum duration characteristic data.

[0035] Test parameter settings: Referring to the MAP (torque-speed-efficiency characteristic diagram) of the electric drive controller, the speed range was determined to be 0-6000 rpm, and 61 test points were divided in 100 rpm intervals: RPM0=0 rpm, RPM1=100 rpm, ..., RPM 60 =6000rpm; torque range is 0N·m (torque at maximum speed without work) to 60N·m (maximum torque), divided into 13 test points at 5N·m intervals (1 / 12 of the maximum torque): NM0=0N·m, NM1=5N·m, ..., NM 12 =60 N·m.

[0036] Operating condition test: Fix the motor controller on the test bench, connect the power, and test each speed-torque combination, such as RPM. 15The test was started at 1500 rpm and NM2 = 10 N·m. During the test, the temperature rise of the MOS module was monitored in real time by a temperature sensor, and the output parameters of the controller were monitored by voltage and current sensors. The test was stopped when any of the following conditions were met, and the current continuous working time was recorded as the maximum duration T under this combination. n : (1) The temperature rise of the MOS module reached 125℃; (2) Output voltage fluctuation exceeds ±5%; (3) Output current distortion rate exceeds 10%.

[0037] Data Processing and Storage: All test data was processed into a two-dimensional data table. Some core data are shown in the table below. The horizontal axis of this data table represents motor speed (unit: rpm), and the vertical axis represents torque (unit: N·m). The intersection of the horizontal and vertical axes represents the maximum continuous operating time (unit: s) for the corresponding combination of speed and torque. This two-dimensional data table was stored in EEPROM in address order, starting at address 0x0000. Each data point occupies 2 bytes, with a storage range of 0-65535s.

[0038]

[0039] 2) Driver intent recognition and torque demand establishment.

[0040] Signal Acquisition and Processing: The analog signal (0-5V) output from the accelerator pedal is acquired via the built-in AD module of the electric drive controller at a frequency of 100Hz. Considering the accelerator pedal's operating boundary conditions (5V for maximum travel, 0.8V for minimum travel, and a response delay ≤10ms) and the signal fluctuation threshold (≤±0.05V), the acquired signal is processed using a moving average filter (averaging five consecutive signal values) to remove high-frequency interference signals.

[0041] Validity verification: Determine whether the filtered signal value is within the effective range of 0.8-5V and whether the signal fluctuation amplitude is less than the set threshold. If the signal is out of range or fluctuates too much, it is judged as an abnormal signal, and the effective signal value of the previous cycle is used; if the signal is abnormal for 3 consecutive cycles, a fault prompt is output and the torque demand value is set to 0 N·m.

[0042] Torque demand conversion: Based on the preset throttle signal-torque mapping relationship (0.8-1.1V corresponds to 0 N·m, 1.1-1.4V corresponds to 0-2 N·m, 1.4-1.7V corresponds to 2-4 N·m, and 2.9-5.0V corresponds to 46-60 N·m), the throttle signal, after validity verification, is converted into a torque demand value. For example, if the collected throttle signal is filtered to 4.1V, corresponding to a torque demand value of 54 N·m, the driver's intention is determined to be acceleration.

[0043] 3) Determining the maximum duration of the current torque.

[0044] Assuming the real-time monitored motor speed is 750 rpm (between RPM7=700 rpm and RPM8=800 rpm), and the torque requirement is 27 N·m (between NM5=25 N·m and NM6=30 N·m), the maximum duration is determined using the following difference calculation method: Retrieve discrete point data from a table: RPM7=700rpm, NM5=25N·m corresponding to T 75 =3300s; RPM7=700rpm, NM6=30N·m corresponding to T 76 =2700s; RPM8=800rpm, NM5=25N·m corresponding to T 85 =3400s; RPM8=800rpm, NM6=30N·m corresponding to T 86 =2800s; Calculate the correction factor and the maximum duration: 1. Speed ​​correction coefficient K1=(T 85 –T 75 ) / (RPM8-RPM7)=(3400-3300) / (800-700)=1.0; The correction duration Trpm7 = T at a torque of 27 N·m corresponding to a speed of 750 rpm 75 ×(1+(750-700)×K1 / 100)=3300×(1+50×1.0 / 100)=4950s; 2. Speed ​​correction coefficient K2=(T 86 –T 76 ) / (RPM8- RPM7)=(2800-2700) / 100=1.0; The correction duration Trpm8 = T at a torque of 27 N·m corresponding to a speed of 750 rpm 76 ×(1+(750-700)×K2 / 100)=2700×(1+50×1.0 / 100)=4050s; 3. Torque correction coefficient K3 = (Trpm8 - Trpm7) / (NM6 - NM5) = (4050 - 4950) / (30 - 25) = -180; The maximum duration of the current operating condition is T = Trpm7 + (K3 × (27-25) / 5) = 4950 + (-180 × 2 / 5) = 4878s.

[0045] 4) Dynamically adjust torque output.

[0046] Calculation of torque demand variation: Setting a 1-second statistical period, calculate the average, maximum, and minimum torque demand values ​​within each period. The cumulative torque change rate is calculated using the following formula: Cumulative torque change rate = (maximum value - minimum value) / average value × 100% Torque output adjustment logic: (1) If the cumulative torque change rate is less than 20%, it is determined that the driver's intention is stable and the current torque is maintained at the average torque demand within the cycle. At the same time, the timer is started to record the continuous output time of the current torque. When the continuous output time exceeds the maximum duration T (4878s) determined in step 3, the torque output is automatically reduced to the rated torque of 3 N·m until the driver adjusts the throttle and the cumulative torque demand change rate exceeds 20%, or the continuous output time is less than T, and then it is restored to the original torque demand value. (2) If the cumulative torque change rate is greater than 20%, it is determined that the driver’s intention has changed significantly (such as rapid acceleration or deceleration). The current torque output timing is stopped immediately, and the process returns to step 2 to re-acquire the throttle signal, identify the driver’s intention, and establish new torque demand information before entering the next control cycle.

[0047] Through testing and verification in this embodiment, the safety control method of the electric drive controller has the following effects: The measured characteristic data are reliable: the measured data of the torque-speed-maximum duration two-dimensional data table are in good agreement with the theoretical heat loss law, and the data repeatability test error is ≤1%; Accurate intent recognition: The torque demand value converted from the throttle signal matches the driving intent 100%, the signal processing delay is ≤10ms, and the anti-interference capability is strong; Effective control logic: When torque demand is stable, the controller can accurately maintain output to the maximum duration, and automatically reduce load after the time limit is reached. The temperature of the MOS module is stable below 125℃, and there is no overheating damage. When the driver's intention changes suddenly, the response is rapid, and the torque output matches the driving intention in real time. Significant practical value: Vehicle manufacturers can independently build test benches to complete data collection and solution verification, reducing their dependence on suppliers' technology; the controller overheating failure rate is reduced by more than 90%, and the service life is extended by 30%, effectively improving the operational safety and stability of electric tricycles.

Claims

1. A safety control method for an electric drive controller, characterized in that, Includes the following steps: Step 1: Establish and store torque-speed-maximum duration characteristic data: Install the motor controller on the test bench, refer to the MAP diagram of the motor controller, and test the maximum duration of stable operation for multiple different torque values ​​from rated torque to maximum torque under different speed conditions. Organize the test results into a two-dimensional data table and store it. The horizontal axis of the two-dimensional data table is the motor speed, the vertical axis is the torque, and the data at the intersection of the horizontal axis and the vertical axis is the maximum sustainable working time under the corresponding speed and torque combination. Step 2: Identify driver intent to establish torque demand information: Acquire throttle analog signals through AD analog-to-digital conversion, analyze the acquired signals in combination with the working boundary conditions and changing characteristics of the throttle, and convert them into torque demand corresponding to throttle operation; Step 3: Determine the maximum duration of the current torque: Based on the torque demand value obtained in Step 2 and the real-time monitored motor speed, search the two-dimensional data table stored in Step 1. If both the torque demand value and the motor speed fall between the discrete data points in the two-dimensional data table, the maximum continuous working time under the current speed and torque demand combination is calculated by the difference. Step 4: Dynamically adjust torque output: Calculate the average value of the torque demand value. If the cumulative change in the torque demand value is less than 20%, maintain the current torque setting at the torque demand value until the working time exceeds the maximum duration determined in Step 3, then reduce the torque to the rated torque. If the cumulative change in torque demand exceeds 20%, return to step two to re-identify the driver's intention and establish new torque demand information, then proceed to the next control cycle.

2. The safety control method for an electric drive controller according to claim 1, characterized in that, The speed interval in the two-dimensional data table mentioned in step one is 100 rpm, the torque interval is 1 / 10 of the maximum torque, and the minimum torque is the minimum torque at which the motor controller can operate stably and continuously.

3. The safety control method for an electric drive controller according to claim 1, characterized in that, The specific method for calculating the difference in step three is as follows: Let the current driver's intended torque NM be between NM n and NM n+1 Between, the current speed RPM is between RPM n and RPM n+1 Between, Tn is the rotational speed in RPM. n Torque NM n The maximum duration of time, T n+1 Rotational speed (RPM) n Torque NM n+1 The maximum duration of time, T n+2 Rotational speed (RPM) n+1 Torque NM n+1 The maximum duration of time, T n+3 Rotational speed (RPM) n+1 Torque NM n The maximum duration of time is calculated as follows: 1) Calculate the speed correction coefficient K1=(T n+3 - T n ) / (RPM n+1 - RPM n ), to obtain the torque NM corresponding to the rotational speed RPM. n The correction duration Trpm n =T n *(1+(RPM-RPM n )*K1); 2) Calculate the speed correction coefficient K2=(T n+2 - T n+1 ) / (RPM n+1 - RPM n ), to obtain the torque NM corresponding to the rotational speed RPM. n+1 The correction duration Trpm n+1 =T n+1 *(1+(RPM-RPM n )*K2); 3) Calculate the torque correction coefficient K3 = (Trpm) n+1 - Trpm n ) / (NM n+1 - NM n ), thus obtaining the maximum duration T = Trpm under the current torque demand NM and speed RPM combination. n *(1+K3*(NM-NM n )).

4. The safety control method for an electric drive controller according to claim 1, characterized in that, The criteria for determining the maximum duration of stable operation in step one are: the temperature rise of the motor controller does not exceed its rated maximum operating temperature, and all electrical performance parameters remain within the preset allowable range.

5. The safety control method for an electric drive controller according to claim 1, characterized in that, Step two, in combination with the working boundary conditions and changing characteristics of the throttle, specifically involves filtering and validating the collected throttle analog signal based on the throttle's maximum stroke, minimum stroke, response delay time, and signal fluctuation threshold, removing abnormal signals, and then converting it into torque demand.

6. The safety control method for an electric drive controller according to claim 1, characterized in that, The calculation method for the cumulative change in torque demand value in step four is as follows: taking a preset time window as the statistical period, calculate the difference between the maximum and minimum torque demand values ​​within the period, and then the ratio of this difference to the average torque demand value within the period.

7. The safety control method for an electric drive controller according to any one of claims 1 to 6, characterized in that, The electric drive controller is used in the field of electric tricycles, and the test bench is a performance test bench for electric tricycle motor controllers.

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