A new energy automobile motor controller with low-temperature environment preheating effect and a control method thereof

Abstract

The application discloses a new energy automobile motor controller with a low-temperature preheating function and a control method thereof, and belongs to the technical field of power electronics of new energy automobiles. In view of the problems of low low-temperature preheating efficiency, uneven heating and poor starting performance of the existing motor controller, the motor controller comprises a main control module, a power conversion module, a low-temperature preheating module and a multi-dimensional temperature detection module; the low-temperature preheating module is provided with independent heating circuits which are directly thermally coupled with IGBT units, bus capacitors and bus inductors of the power conversion module; the main control module controls the start-stop and heating power of the low-temperature preheating module according to temperature data collected by the multi-dimensional temperature detection module. The application realizes accurate directional heating of core components, improves the low-temperature starting performance and operation reliability of the motor controller, and has good engineering practicability and compatibility.

Description

Technical Field

[0001] This invention belongs to the field of power electronics technology for new energy vehicles, and particularly relates to a new energy vehicle motor controller and its control method with low-temperature environment preheating effect. Background Technology

[0002] The motor controller of a new energy vehicle is a core power electronic component of the drive system. It typically contains core components such as insulated-gate bipolar transistor (IGBT) modules, DC bus support capacitors (e.g., film capacitors), bus inductors, and drive circuits. The electrical performance, reliability, and lifespan of these semiconductor devices and passive components are closely related to their operating temperature. In low-temperature environments, especially in winter in northern my country and high-altitude areas, the motor controller faces severe challenges: the on-state voltage drop and switching losses of the IGBTs increase significantly, the capacitance of the film capacitors decreases, and the equivalent series resistance rises sharply. This leads to a reduction in the overall efficiency and output capability of the controller, and may cause starting delays, torque fluctuations, or even starting failures, seriously affecting the vehicle's driving performance and reliability.

[0003] To cope with low-temperature environments, the following are the main low-temperature adaptation solutions for motor controllers in existing technologies: The first type of solution is a design without active preheating. This solution relies entirely on the heat generated by the motor controller's own power loss after it starts driving the motor to gradually raise the internal temperature. In extremely low temperatures, the core components of the controller are completely cold at the beginning of startup, and performance degradation is unavoidable. This results in sluggish and uneven power response during vehicle start-up, and the cold start process also has an adverse effect on the lifespan of the components.

[0004] The second type of solution is passive preheating design. This solution typically uses heating elements such as positive temperature coefficient (PTC) heaters or resistance wires, mounted on the housing or heat sink of the motor controller. The controller's overall structure is heated, and the internal components are indirectly heated via heat conduction. For example, preheating the controller via a housing heating device. This type of solution suffers from a long heat conduction path, high thermal resistance, uneven heating, and slow thermal response. It often takes a long time (e.g., more than 10 minutes) to rise from a low temperature to the operating temperature, consuming additional power from the vehicle battery, resulting in low preheating efficiency.

[0005] The third type of solution is the waste heat utilization design. This solution attempts to utilize the waste heat generated by the operation of other vehicle systems (such as the power battery pack and motor) and transfer the heat to the motor controller through the coolant circulation loop. For example, some vehicle thermal management systems will introduce the waste heat of the battery coolant into the controller housing. However, this solution relies on other components to generate waste heat first, and cannot achieve rapid preheating when the vehicle is powered on and the driver has an immediate need for driving. In other words, it does not have the ability to preheat as soon as it is powered on, and the timing of preheating is uncontrollable.

[0006] In summary, existing low-temperature adaptation solutions for motor controllers either fail to guarantee low-temperature performance due to the lack of preheating functionality, or suffer from low preheating efficiency, high energy consumption, slow heating rate, and uneven heating of internal components due to the use of indirect, overall heating methods. In particular, there is a lack of a preheating mechanism that can directly, quickly, and accurately transfer heat to the most temperature-sensitive core components such as IGBTs and DC bus capacitors, and start them immediately upon power-on. This results in poor reliability of motor controllers during startup under extremely cold conditions, severe performance degradation, and shortened component lifespan, becoming one of the technical bottlenecks restricting the widespread application of new energy vehicles in vast low-temperature regions.

[0007] Therefore, there is an urgent need for an innovative motor controller design to overcome the shortcomings of the existing technology. Summary of the Invention

[0008] This invention provides a new energy vehicle motor controller and its control method with precise low-temperature preheating function, aiming to solve the problems of performance degradation of core components, difficulty in starting, low preheating efficiency and shortened life of existing motor controllers in low-temperature environments.

[0009] To solve the above-mentioned technical problems, the specific technical solution of the present invention includes: Main control module; The power conversion module includes IGBT units, bus capacitors, and bus inductors; The low-temperature preheating module includes an IGBT heating circuit, a capacitor heating circuit, and an inductor heating circuit that are electrically and thermally independent of each other. The heating element of the IGBT heating circuit is directly thermally coupled to the DBC substrate of the IGBT unit. The heating element of the capacitor heating circuit is directly thermally coupled to the metal shell of the bus capacitor. The heating element of the inductor heating circuit is directly thermally coupled to the winding surface of the bus inductor. A multi-dimensional temperature detection module includes at least a first temperature sensor, a second temperature sensor, and a third temperature sensor. The first temperature sensor is disposed on the chip package surface of the IGBT unit, the second temperature sensor is disposed at the root of the pin of the bus capacitor, and the third temperature sensor is disposed in the middle of the winding of the bus inductor. The main control module is connected to the multi-dimensional temperature detection module and the low-temperature preheating module respectively, and is used to dynamically adjust the total heating power of the low-temperature preheating module and control the start and stop of the low-temperature preheating module according to the real-time temperature of each core component collected by the first, second and third temperature sensors.

[0010] In some embodiments of this application, the IGBT heating circuit includes a PTC heating element connected to the IGBT chip, wherein the PTC heating element is tightly attached to the surface of the DBC substrate of the IGBT unit via thermally conductive silicone. The capacitor heating circuit includes an alloy thin film heating wire, which is tightly wound in a spiral manner around the metal shell of the bus capacitor, and the heating wire is wrapped with aerogel insulation cotton. The inductor heating circuit includes a flexible silicone heating film covering an area of ​​not less than 80% of the surface area of ​​the bus inductor. The flexible silicone heating film is adhered to the winding surface of the bus inductor by a high-temperature resistant pressure-sensitive adhesive.

[0011] In some embodiments of this application, the low-temperature preheating module further includes: The power regulation unit is electrically connected to the common power supply terminal of the IGBT heating circuit, the capacitor heating circuit and the inductor heating circuit. It is used to receive the pulse width modulation (PWM) signal from the main control module and continuously adjust the total heating power of the low temperature preheating module within the range of 5W-50W. The circuit switching unit is connected in series in the main power supply circuit of the low temperature preheating module, and is used to connect or disconnect the power supply of all preheating circuits according to the instructions of the main control module.

[0012] In some embodiments of this application, the power regulation unit includes a MOSFET switch, a precision sampling resistor, and a PWM controller. The control terminal of the MOSFET switch receives the PWM signal output by the main control module, and the precision sampling resistor is connected in series in the total power supply circuit for real-time acquisition of the circuit operating current. The circuit switching unit includes a relay, whose normally open contacts are connected in series on the main power supply line of the low-temperature preheating module.

[0013] In some embodiments of this application, the multi-dimensional temperature detection module further includes: The fourth temperature sensor is located on the outer surface of the aluminum alloy housing of the motor controller and is used to collect ambient temperature. The fifth temperature sensor is installed on the inner wall of the coolant channel inside the motor controller to monitor the coolant temperature. The main control module uses a Kalman filter algorithm to reduce noise in the collected raw temperature data.

[0014] In some embodiments of this application, the main control module presets a first temperature threshold T1, a second temperature threshold T2, and a third temperature threshold T3, wherein T1 = -10℃, T2 = 5℃, and T3 = 85℃, and T1 <T2<T3; The main control module is configured to: start the low-temperature preheating module when the ambient temperature is ≤T1 or the temperature of any one of the IGBT unit, bus capacitor, or bus inductor is ≤0℃; dynamically adjust the total heating power by calculating the duty cycle of the PWM signal based on the maximum difference between the real-time temperature of each core component and T2 using a proportional-integral-derivative (PID) control algorithm; stop the low-temperature preheating module when the temperature of all core components is ≥T2 and the fluctuation does not exceed ±1℃ within 30 seconds; and immediately stop the low-temperature preheating module and trigger an alarm when the temperature of any core component is ≥T3.

[0015] In some embodiments of this application, the power regulation strategy of the main control module is specifically as follows: When the maximum difference between the real-time temperature of each core component and T2 is ≥15℃, a PWM signal with a 100% duty cycle is output, corresponding to a total heating power of 50W. When the maximum temperature difference is 5℃-10℃, a PWM signal with a 60% duty cycle is output, corresponding to a total heating power of approximately 30W. When the maximum difference is less than 5℃, a PWM signal with a 30% duty cycle is output, corresponding to a total heating power of approximately 15W for heat preservation.

[0016] In some embodiments of this application, the main control module is also configured to continuously monitor the temperature of each core component after the motor controller enters normal operating mode; if the temperature of any core component drops below 0°C, the low-temperature preheating module is automatically started to heat for 60 seconds with a power of 20W for short-term supplementary heating, and then automatically stops after the supplementary heating is completed.

[0017] In some embodiments of this application, a fault protection module is also included, whose sampling terminal is connected in series in the main power supply circuit of the low temperature preheating module for real-time monitoring of the circuit's operating current and operating voltage; when the operating current exceeds 8A or the operating voltage exceeds 15V, the fault protection module immediately sends a hardware interrupt signal to the main control module and cuts off the power supply to the preheating circuit.

[0018] In some embodiments of this application, the low-temperature preheating control method for a new energy vehicle motor controller based on any one of the above-described methods includes the following steps: S1: After the vehicle is powered on or remotely started, the system completes initialization, and the multi-dimensional temperature detection module collects the real-time temperature of the IGBT unit, bus capacitor, bus inductor, and ambient temperature. S2: The main control module determines whether the low-temperature preheating start-up conditions are met: if the ambient temperature is ≤-10℃ or the temperature of any core component is ≤0℃, the preheating conditions are met and the process proceeds to step S3; otherwise, the process directly enters the normal operation mode. S3: The main control module sends a pull-in command to the loop switching unit to connect the preheating loop power supply; at the same time, based on the maximum difference between the real-time temperature of each core component and the target temperature of 5℃, the initial PWM duty cycle is calculated by the PID algorithm, and the initial heating power is output. S4: Updates the temperature data of each core component every 100ms, recalculates the maximum difference and dynamically adjusts the PWM duty cycle to achieve closed-loop regulation of heating power; at the same time, the fault protection module monitors the circuit current and voltage in real time, and the main control module monitors whether the temperature of each core component exceeds 85℃ in real time. If the fault protection module detects that the circuit current is >8A or the voltage is >15V, or the main control module detects that the temperature of any core component is ≥85℃, the power supply to the preheating circuit is immediately cut off, and a "preheating circuit fault" alarm signal is sent to the vehicle controller via the CAN bus. S5: When the temperature of all core components is ≥5℃ and the fluctuation does not exceed ±1℃ within 30 seconds, the preheating is determined to be complete; the main control module first sets the PWM duty cycle to zero, and then the control loop switching unit disconnects the power supply to the preheating loop and enters the normal operation mode. S6: In normal operating mode, continuously monitor the temperature of each core component; if the temperature of any core component drops below 0℃, start the low temperature preheating module to heat for 60 seconds at 20W power to replenish the heat, and return to normal operating mode after the heat replenishment is completed.

[0019] Compared with existing technologies, the advantages of this invention are as follows: by employing independent preheating circuits that are directly thermally coupled to the IGBT units, bus capacitors, and bus inductors in the power conversion module, directional heating of the core components of the motor controller is achieved, effectively shortening the heat conduction path and improving heat utilization efficiency; combined with multi-dimensional temperature detection and closed-loop control covering the core components, environment, and cooling system, the heating power can be dynamically adjusted according to the real-time temperature of each core component, ensuring uniform heating of each component and reducing thermal shock damage caused by sudden temperature changes; the preheating process does not rely on the residual heat of other vehicle systems and can be started on demand after power-on, effectively improving the starting performance and operational stability of the motor controller in low-temperature environments; at the same time, the preheating module of this invention is highly integrated inside the controller, without requiring changes to the external interface of the existing controller and the overall vehicle thermal management architecture, exhibiting good engineering practicality and compatibility. Attached Figure Description

[0020] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 This is a schematic diagram of the overall module framework of the motor controller in this application embodiment; Figure 2 This is an internal frame diagram of the low-temperature preheating module in an embodiment of this application; Figure 3 This is a diagram showing the layout of the multi-dimensional temperature detection module in this embodiment. Detailed Implementation

[0021] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0022] To better understand the purpose, structure, and function of this invention, the invention will be described in further detail below with reference to the accompanying drawings.

[0023] Example 1 like Figure 1 As shown, the new energy vehicle motor controller with low-temperature preheating function provided in this embodiment adopts a modular integrated design, mainly including a main control module 1, a power conversion module 2, a low-temperature preheating module 3, a multi-dimensional temperature detection module 4, a power management module 5, and a fault protection module 6. Each module is connected through a standardized interface and is installed inside the original motor controller housing without altering the controller's external dimensions or the vehicle interface.

[0024] The input of the power management module 5 is directly connected to the vehicle's 12V low-voltage auxiliary power supply. Its output is divided into multiple independent power supply branches, providing stable operating voltages for the main control module 1, the drive circuit of the power conversion module 2, the low-temperature preheating module 3, the multi-dimensional temperature detection module 4, and the fault protection module 6. Among them, the low-temperature preheating module 3 is powered by an independent low-voltage preheating power supply branch, which is electrically isolated from the power supply circuits of other modules to avoid electromagnetic interference to the control circuit during the preheating process.

[0025] The main control module 1 is connected to the multi-dimensional temperature detection module 4 via an SPI communication interface with a sampling frequency of 10Hz; it is connected to the power regulation unit 32 in the low-temperature preheating module 3 via an I2C communication interface to send PWM control signals and receive current feedback data; it communicates with the vehicle controller and fault protection module 6 via a CAN bus interface to realize status reporting and command interaction; at the same time, it outputs motor drive PWM signals to the power conversion module 2 through an optical fiber isolated drive circuit to ensure safe isolation of the high and low voltage systems.

[0026] The preheating loop unit 31 of the low-temperature preheating module 3 is connected to the low-voltage preheating power supply of the power management module 5 through the loop switching unit 33. Its heating element is directly and physically bonded to the IGBT unit, bus capacitor, and bus inductor of the power conversion module 2 to achieve thermal coupling. The current sampling terminal and voltage sampling terminal of the fault protection module 6 are connected in series in the total power supply loop of the low-temperature preheating module 3 for real-time monitoring of the loop's operating status.

[0027] In this embodiment, the main control module 1 uses an STM32H743VIT6 industrial-grade microcontroller, which has a built-in Cortex-M7 core, a main frequency of 400MHz, a double-precision floating-point arithmetic unit and 2MB Flash memory. It can run PID control algorithm, Kalman filter algorithm, CAN bus communication protocol and fault diagnosis program at the same time. The single cycle operation time is less than 1ms, which fully meets the real-time control requirements of the low temperature preheating system.

[0028] The main control module 1 has complete low-temperature preheating control logic and parameter thresholds pre-stored inside. It can independently complete temperature acquisition, preheating decision, power adjustment and fault handling without relying on the computing resources of the vehicle controller.

[0029] Power conversion module 2 is the core power unit for motor drive, including IGBT units, bus capacitors, and bus inductors. In this embodiment, the IGBT unit uses an Infineon FF1400R12IP4 six-in-one IGBT module with a rated voltage of 1200V and a rated current of 1400A; the bus capacitor uses a metallized polypropylene film capacitor with a rated voltage of 450V and a capacitance of 1000μF; the bus inductor uses an iron-silicon-aluminum magnetic core inductor with an inductance of 100μH and a rated current of 200A.

[0030] The three components mentioned above are the core components of the motor controller that are most sensitive to temperature. Their performance degrades most significantly in low-temperature environments. Therefore, this invention designs independent directional heating circuits for these three components.

[0031] like Figure 2 As shown, the low-temperature preheating module 3 is the core of this invention for achieving precise low-temperature preheating. It mainly consists of three parts: a preheating loop unit 31, a power adjustment unit 32, and a loop switching unit 33. This module adopts a zoned independent heating architecture, realizing point-to-point precise heating of the three core components.

[0032] The preheating circuit unit 31 includes three electrically and thermally independent heating circuits. The three circuits are electrically connected in parallel to the output terminal of the power adjustment unit 32. Physically and thermally, they do not share a common heat conduction structure. The circuits are separated by a 1mm thick aerogel insulation strip to avoid mutual heat interference.

[0033] IGBT heating circuit 311: Employs a PTC heating element perfectly matched to the IGBT chip size, measuring 120mm × 80mm, with a rated voltage of 12V and a rated power of 20W. This PTC heating element is tightly bonded to the surface of the IGBT module's DBC substrate using high thermal conductivity silicone with a thermal conductivity ≥200W / (m·K), with a bonding gap of less than 0.1mm. This keeps the thermal resistance below 0.1℃ / W, ensuring that over 90% of the heat is directly transferred to the IGBT chip junction region.

[0034] Capacitor heating circuit 312: Utilizes a capacitor with a diameter of 0.15mm and a resistivity of 1.0×10⁻⁶. ﹣6 The Ω·m nickel-chromium alloy thin-film heating wire is tightly wound in a spiral pattern around the cylindrical metal shell of the bus capacitor, with a winding spacing of 2mm and a total winding length of approximately 5m. The rated power is 15W. The heating wire is wrapped with a 1.5mm thick aerogel insulation cotton, which has a thermal conductivity of ≤0.03W / (m·K), reducing the heat loss rate during capacitor heating to below 10%.

[0035] Inductor heating circuit 313: Utilizes a flexible silicone heating film, perfectly matched to the surface of the busbar inductor, covering an area of ​​no less than 85% of the inductor's surface area, with a rated voltage of 12V and a rated power of 15W. This heating film is directly adhered to the inductor's core and winding surface using high-temperature resistant pressure-sensitive adhesive, adapting to the inductor's irregular shape and ensuring uniform heating.

[0036] The power regulation unit 32 consists of an IRF540N MOSFET switch, a 0.1Ω / 1W precision sampling resistor, and a TL494 PWM controller. The PWM signal with a duty cycle of 0%-100% output from the main control module 1 drives the MOSFET to turn on and off. By changing the PWM duty cycle, the total current flowing through the preheating circuit can be continuously adjusted, thereby achieving precise adjustment of the preheating power within the range of 5W-50W.

[0037] A precision sampling resistor is connected in series in the main power supply circuit to collect the circuit's operating current in real time and feed the current signal back to the main control module 1, forming a current closed-loop control to prevent power overload. In this embodiment, the power regulation accuracy can reach ±1W, meeting the requirements of dynamic power adjustment.

[0038] The circuit switching unit 33 uses an HF3FF-012-1ZS type 12V DC relay, whose normally open contacts are connected in series on the main power supply line of the low-temperature preheating module 3. The relay coil is controlled by the main control module 1. When preheating is required, the main control module 1 outputs a high level to make the relay energize and connect the preheating power supply; after preheating is completed, the main control module 1 outputs a low level to release the relay and completely disconnect the preheating circuit.

[0039] The reason for choosing a relay instead of a semiconductor switch is that the breaking resistance of a relay can reach 10 ohms. 9 With a current rating of Ω or higher, the leakage current of the preheating circuit can be completely cut off, preventing the preheating module from consuming additional power when the controller is working normally. It also has stronger overcurrent capability and anti-interference capability.

[0040] like Figure 3 As shown, the multi-dimensional temperature detection module 4 employs five DS18B20 high-precision digital temperature sensors, with a measurement range of -55℃ to +125℃ and a measurement accuracy of ±0.5℃. The five sensors are installed in different locations, forming a comprehensive temperature detection network covering the core components, environment, and cooling system.

[0041] First temperature sensor 41: It is directly attached to the IGBT chip package surface closest to the DC bus in the IGBT module by thermally conductive adhesive, and is used to directly sense the chip junction temperature. The second temperature sensor 42 is installed at the root of the positive lead of the bus capacitor by spot welding. This location has the shortest heat conduction path and can most sensitively reflect the temperature of the capacitor core. The third temperature sensor 43 is attached to the middle of the surface of the bus inductor winding with thermally conductive adhesive and is used to monitor the core temperature of the inductor winding. The fourth temperature sensor 44 is installed on the outer surface of the aluminum alloy housing of the motor controller, away from the heat dissipation vents and heat-generating elements, and is used to accurately collect the ambient temperature of the controller. Fifth temperature sensor 45: Installed on the inner wall of the inlet of the coolant flow channel inside the controller, used to monitor the temperature of the coolant in the vehicle's thermal management system.

[0042] All temperature sensors are connected to the main control module 1 via a single bus, with a sampling frequency of 10Hz. The main control module 1 processes the acquired raw temperature data using a Kalman filter algorithm to eliminate electromagnetic interference from motor operation and random noise from the sensors. The filtered temperature measurement error can be controlled within ±0.3℃.

[0043] The fault protection module 6 consists of a current transformer, a voltage comparator, and a hardware interrupt circuit. The current transformer is connected in series with the main power supply line of the preheating circuit to monitor the circuit's operating current in real time; the input of the voltage comparator is connected to the power supply terminal of the preheating circuit to monitor the circuit's operating voltage.

[0044] When the fault protection module 6 detects that the circuit operating current exceeds 8A or the operating voltage exceeds 15V, it will immediately generate a hardware interrupt signal and send it directly to the non-maskable interrupt pin of the main control module 1. After receiving the interrupt signal, the main control module 1 will disconnect the relay of the circuit switching unit 33 within 10ms, cut off the power supply to the preheating circuit, and send the fault code and alarm information to the vehicle controller via the CAN bus.

[0045] Example 2 Based on the motor controller hardware structure described in Embodiment 1, this embodiment provides a low-temperature preheating control method, the specific steps of which are as follows: S1: System Power-On and Initialization After the vehicle is powered on (ON position) or remotely started, the power management module 5 begins to operate, providing a stable operating voltage to all modules within the controller. The main control module 1 completes its startup, initializing the I / O ports, PWM output, ADC sampling, CAN communication interface, and interrupt service routine. This process takes approximately 200ms.

[0046] S2: Temperature Acquisition and Preheating Condition Judgment The multi-dimensional temperature detection module 4 starts working, collecting temperature data from the first to fifth temperature sensors 41-45 and sending it to the main control module 1. The main control module 1 reads the ambient temperature (fourth sensor 44) and the temperatures of the three core components (first, second, and third sensors 41, 42, and 43).

[0047] The main control module 1 has three preset temperature threshold levels: The first temperature threshold T1 = -10℃ (ambient temperature trigger threshold) The second temperature threshold T2 = 5℃ (target operating temperature of the component) The third temperature threshold T3 = 85℃ (component overheat protection threshold) Threshold design basis: T1=-10℃: When the ambient temperature is below -10℃, the on-state voltage drop of the IGBT will increase by more than 30%, the capacitance of the film capacitor will decrease by more than 20%, the equivalent series resistance will increase by 3 times, and the overall efficiency of the controller will be significantly reduced. T2=5℃: When the temperature of IGBT, bus capacitor and bus inductor is above 5℃, the electrical performance can be restored to more than 90% of the normal temperature condition, which fully meets the power requirements for normal vehicle operation. T3=85℃: When this temperature is exceeded, the Curie temperature of the PTC heating element is triggered, the resistance rises sharply, the heating power drops significantly, and the insulation material of the core component may age prematurely.

[0048] Preheat start judgment logic: If the ambient temperature is greater than T1 and the temperature of all core components is greater than 0°C, then it is determined that no preheating is required, and the process directly proceeds to step S7 (normal working mode). Otherwise, as long as either the ambient temperature is ≤T1 or the temperature of any core component is ≤0℃, the low-temperature preheating start-up condition is met, and the process proceeds to step S3.

[0049] Changing the original "AND" logic to "OR" logic can cover more real-world low-temperature scenarios. For example, if a vehicle is parked in an environment of -5°C for more than 24 hours, even though the ambient temperature is higher than T1, the temperature of the core components may drop below 0°C due to prolonged heat dissipation, and preheating will still be required in this case.

[0050] S3: Start preheating and output initial heating power The main control module 1 first sends a "low temperature preheating" status message to the vehicle controller via the CAN bus, and the vehicle's instrument panel displays a corresponding prompt. Subsequently, the main control module 1 sends a high-level command to the circuit switching unit 33, causing the relay to engage and connecting the preheating circuit for power supply.

[0051] Meanwhile, the main control module 1 calculates the maximum difference ΔT_max between the real-time temperature of each core component and the target temperature T2, and calculates the initial PWM duty cycle using the built-in PID control algorithm to output the initial heating power. The reason for using the "maximum difference" to calculate the duty cycle is to ensure that the component with the slowest temperature rise (usually the bus capacitor) can also reach the target temperature within the specified time, avoiding the situation where "the IGBT has reached the target, but the capacitor has not."

[0052] Initial power regulation strategy: When ΔT_max≥15℃, output a PWM signal with 100% duty cycle, corresponding to a total heating power of 50W; When 5℃≤ΔT_max<15℃, output a PWM signal with a duty cycle of (ΔT_max / 15×100%). When ΔT_max < 5℃, a PWM signal with a 30% duty cycle is output, corresponding to a total heating power of 15W.

[0053] S4: Dynamic power adjustment and real-time monitoring After preheating and startup, the system enters the closed-loop control phase: Dynamic power regulation: The main control module 1 reads the latest core component temperature every 100ms, recalculates ΔT_max, and updates the PID output in real time, dynamically adjusting the PWM duty cycle. When ΔT_max decreases to 5-10℃, the duty cycle drops to 60% (approximately 30W); when ΔT_max is less than 5℃, the duty cycle further decreases to 30% (approximately 15W) for heat preservation, avoiding temperature overshoot and thermal shock.

[0054] Real-time fault monitoring: Fault protection module 6 continuously monitors the operating current and voltage of the preheating circuit, while main control module 1 continuously compares the temperature of each core component with the overheat protection threshold T3. Fault protection is immediately activated if any of the following conditions occur: Circuit operating current > 8A; Circuit operating voltage >15V; The temperature of any core component is ≥85℃.

[0055] Fault protection action: The main control module 1 immediately sets the PWM duty cycle to zero, then disconnects the relay of the circuit switching unit 33, cuts off the power supply to the preheating circuit, and sends fault codes and alarm information to the vehicle controller via the CAN bus.

[0056] S5: Preheating Completion Detection and Mode Switching When the temperatures of the three core components monitored by the first, second, and third temperature sensors 41, 42, and 43 are all consistently ≥5℃ and fluctuate by no more than ±1℃ within 30 seconds, the main control module 1 determines that preheating is complete. The condition of "fluctuation by no more than ±1℃ within 30 seconds" is added to ensure that the core component temperatures have truly stabilized and to avoid misjudgments caused by instantaneous fluctuations in the temperature sensors.

[0057] After preheating is complete, the main control module 1 first sets the PWM duty cycle to zero, and then the relay of the control loop switching unit 33 is disconnected, completely cutting off the power supply to the preheating circuit. Subsequently, a "preheating complete, ready" signal is sent to the vehicle controller via the CAN bus, and the vehicle's instrument panel indicates to the driver that the vehicle can proceed normally.

[0058] Typical operating condition example: In an environment of -20℃, the initial temperature after the vehicle is powered on is: IGBT -18℃, capacitor -19℃, inductor -17℃, ΔT_max=24℃, and the system outputs 100% duty cycle (50W) for heating; after 1 minute, the temperatures are -5℃, -6℃, and -4℃ respectively, ΔT_max=11℃, and the duty cycle is adjusted to 60% (30W); after 2 minutes, the temperatures are 2℃, 1℃, and 3℃ respectively, ΔT_max=4℃, and the duty cycle is adjusted to 30% (15W); after 2 minutes and 40 seconds, the temperature of all components is ≥5℃ and the fluctuation within 30 seconds is ≤±1℃, the preheating is completed, and the total time is 2 minutes and 40 seconds.

[0059] S6: Normal Operation and Heating Mechanism The controller enters normal operating mode (S7), and the power conversion module 2 begins to receive drive signals from the main control module 1 to control the IGBT bridge arm to drive the motor.

[0060] During vehicle operation, the multi-dimensional temperature detection module 4 operates continuously. If, under low speed, low load, or extremely cold conditions (such as -30℃), the power conversion module's own heating power is insufficient, causing the temperature of any core component to drop below 0℃, the main control module 1 will restart the low-temperature preheating module 3 to perform a short-term, low-power reheating cycle: heating with 20W power for 60 seconds and then automatically stopping to ensure that the components always operate within a suitable temperature window.

[0061] Typical application scenario of the heat compensation mechanism: When a vehicle is traveling at a low speed of less than 20km / h in an environment of -20℃, the self-heating power of the power conversion module is less than 10W, which is not enough to maintain the temperature of the core components. At this time, heat compensation can effectively prevent the performance of the components from degrading again.

[0062] S7: Normal working mode This is the standard operating state of the controller driving the motor. Based on the driver's accelerator pedal signal and the vehicle controller's instructions, the main control module 1 outputs a corresponding PWM signal to control the power conversion module 2, thereby regulating the motor's speed and torque. In this mode, the multi-dimensional temperature detection module 4 and the fault protection module 6 continue to operate to ensure safe system operation.

[0063] The technical effects achieved by this application through the above technical solution are as follows: This application achieves precise point-to-point heat transfer by directly thermally coupling the heating element with three components: IGBT, bus capacitor, and bus inductor. At the same time, it combines a multi-dimensional temperature detection network and PID intelligent closed-loop control to achieve precise and gentle regulation of the preheating process.

[0064] In the description of this application, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0065] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0066] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0067] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0068] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A new energy vehicle motor controller with low-temperature preheating function, characterized in that, include: Main control module; The power conversion module includes IGBT units, bus capacitors, and bus inductors; The low-temperature preheating module includes an IGBT heating circuit, a capacitor heating circuit, and an inductor heating circuit that are electrically and thermally independent of each other. The heating element of the IGBT heating circuit is directly thermally coupled to the DBC substrate of the IGBT unit. The heating element of the capacitor heating circuit is directly thermally coupled to the metal shell of the bus capacitor. The heating element of the inductor heating circuit is directly thermally coupled to the winding surface of the bus inductor. A multi-dimensional temperature detection module includes at least a first temperature sensor, a second temperature sensor, and a third temperature sensor. The first temperature sensor is disposed on the chip package surface of the IGBT unit, the second temperature sensor is disposed at the root of the pin of the bus capacitor, and the third temperature sensor is disposed in the middle of the winding of the bus inductor. The main control module is connected to the multi-dimensional temperature detection module and the low-temperature preheating module respectively, and is used to dynamically adjust the total heating power of the low-temperature preheating module and control the start and stop of the low-temperature preheating module according to the real-time temperature of each core component collected by the first, second and third temperature sensors.

2. A new energy vehicle motor controller with low-temperature preheating function according to claim 1, characterized in that, The IGBT heating circuit includes a PTC heating element connected to the IGBT chip, and the PTC heating element is tightly attached to the surface of the DBC substrate of the IGBT unit by thermally conductive silicone. The capacitor heating circuit includes an alloy thin film heating wire, which is tightly wound in a spiral manner around the metal shell of the bus capacitor, and the heating wire is wrapped with aerogel insulation cotton. The inductor heating circuit includes a flexible silicone heating film covering an area of ​​not less than 80% of the surface area of ​​the bus inductor. The flexible silicone heating film is adhered to the winding surface of the bus inductor by a high-temperature resistant pressure-sensitive adhesive.

3. A new energy vehicle motor controller with low-temperature preheating function according to claim 1, characterized in that, The low-temperature preheating module also includes: The power adjustment unit is electrically connected to the common power supply terminal of the IGBT heating circuit, the capacitor heating circuit and the inductor heating circuit. It is used to receive the pulse width modulation signal from the main control module and continuously adjust the total heating power of the low temperature preheating module within the range of 5W-50W. The circuit switching unit is connected in series in the main power supply circuit of the low temperature preheating module, and is used to connect or disconnect the power supply of all preheating circuits according to the instructions of the main control module.

4. A new energy vehicle motor controller with low-temperature preheating function according to claim 3, characterized in that, The power regulation unit includes a MOSFET switch, a precision sampling resistor, and a PWM controller. The control terminal of the MOSFET switch receives the PWM signal output by the main control module. The precision sampling resistor is connected in series in the total power supply circuit for real-time acquisition of the circuit operating current. The circuit switching unit includes a relay, whose normally open contacts are connected in series on the main power supply line of the low-temperature preheating module.

5. A new energy vehicle motor controller with low-temperature preheating function according to claim 1, characterized in that, The multi-dimensional temperature detection module also includes: The fourth temperature sensor is located on the outer surface of the aluminum alloy housing of the motor controller and is used to collect ambient temperature. The fifth temperature sensor is installed on the inner wall of the coolant channel inside the motor controller to monitor the coolant temperature. The main control module uses a Kalman filter algorithm to reduce noise in the collected raw temperature data.

6. A new energy vehicle motor controller with low-temperature preheating function according to claim 5, characterized in that, The main control module is preset with a first temperature threshold T1, a second temperature threshold T2, and a third temperature threshold T3, where T1 = -10℃, T2 = 5℃, and T3 = 85℃, and T1... <T2<T3; The main control module is configured to start the low-temperature preheating module when the ambient temperature is ≤T1 or the temperature of any one of the IGBT unit, bus capacitor, or bus inductor is ≤0℃. Based on the maximum difference between the real-time temperature of each core component and T2, the duty cycle of the PWM signal is calculated using a proportional-integral-derivative control algorithm to dynamically adjust the total heating power. When the temperature of all core components is ≥ T2 and the fluctuation does not exceed ±1℃ within 30 seconds, the low-temperature preheating module is stopped. When the temperature of any core component is ≥ T3, the low-temperature preheating module is immediately stopped and an alarm is triggered.

7. A new energy vehicle motor controller with low-temperature preheating function according to claim 6, characterized in that, The power regulation strategy of the main control module is as follows: When the maximum difference between the real-time temperature of each core component and T2 is ≥15℃, a PWM signal with a 100% duty cycle is output, corresponding to a total heating power of 50W. When the maximum temperature difference is 5℃-10℃, a PWM signal with a 60% duty cycle is output, corresponding to a total heating power of approximately 30W. When the maximum difference is less than 5℃, a PWM signal with a 30% duty cycle is output, corresponding to a total heating power of approximately 15W for heat preservation.

8. A new energy vehicle motor controller with low-temperature preheating function according to claim 6, characterized in that, The main control module is also configured to continuously monitor the temperature of each core component after the motor controller enters normal operating mode; if the temperature of any core component drops below 0°C, the low-temperature preheating module is automatically activated to heat for 60 seconds at a power of 20W for short-term supplementary heating, and then automatically stops after the supplementary heating is completed.

9. A new energy vehicle motor controller with low-temperature preheating function according to claim 1, characterized in that, Also includes: The fault protection module has its sampling terminal connected in series in the main power supply circuit of the low temperature preheating module, which is used to monitor the working current and working voltage of the circuit in real time. When the operating current exceeds 8A or the operating voltage exceeds 15V, the fault protection module immediately sends a hardware interrupt signal to the main control module and cuts off the power supply to the preheating circuit.

10. A low-temperature preheating control method for a new energy vehicle motor controller based on any one of claims 1-9, characterized in that, Includes the following steps: S1: After the vehicle is powered on or remotely started, the system completes initialization, and the multi-dimensional temperature detection module collects the real-time temperature of the IGBT unit, bus capacitor, bus inductor, and ambient temperature. S2: The main control module determines whether the low-temperature preheating start-up conditions are met: if the ambient temperature is ≤-10℃ or the temperature of any core component is ≤0℃, then the preheating conditions are met and the process proceeds to step S3. Otherwise, it will directly enter normal working mode; S3: The main control module sends a pull-in command to the loop switching unit to connect the preheating loop power supply; at the same time, based on the maximum difference between the real-time temperature of each core component and the target temperature of 5℃, the initial PWM duty cycle is calculated by the PID algorithm, and the initial heating power is output. S4: Update the temperature data of each core component every 100ms, recalculate the maximum difference and dynamically adjust the PWM duty cycle to achieve closed-loop regulation of heating power; Meanwhile, the fault protection module monitors the circuit current and voltage in real time, and the main control module monitors whether the temperature of each core component exceeds 85℃ in real time. If the fault protection module detects that the circuit current is >8A or the voltage is >15V, or the main control module detects that the temperature of any core component is ≥85℃, the power supply to the preheating circuit will be cut off immediately, and a "preheating circuit fault" alarm signal will be sent to the vehicle controller via the CAN bus. S5: When the temperature of all core components is ≥5℃ and the fluctuation does not exceed ±1℃ within 30 seconds, the preheating is determined to be complete; the main control module first sets the PWM duty cycle to zero, and then the control loop switching unit disconnects the power supply to the preheating loop and enters the normal operation mode. S6: In normal operating mode, continuously monitor the temperature of each core component; if the temperature of any core component drops below 0℃, start the low temperature preheating module to heat for 60 seconds at 20W power to replenish the heat, and return to normal operating mode after the heat replenishment is completed.

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