New energy automobile electric compressor preheating structure and control method

Abstract

The invention discloses a new energy automobile electric compressor preheating structure and a control method, and relates to the technical field of new energy automobile heat management. The method comprises the three steps of heat source collaborative recovery, heat demand dynamic distribution and self-starting collaborative execution, specifically, motor stator waste heat and compression refrigerant waste heat are recovered through a heat conduction fin array and a spiral flow channel, and a shared heat conduction medium is guided in; based on a fuzzy PID controller, a heat flow guide valve is dynamically adjusted to distribute heat flow according to the lubricating oil way temperature, the suction superheat degree and the shell temperature; the generator is triggered to be rapidly heated in a locked-rotor mode at the ultralow temperature, the preheating requirement is pre-judged in combination with a heat attenuation model, the structure comprises a temperature sensor set, a three-way heat flow guide valve and an embedded MCU processor, efficient waste heat utilization is achieved, external energy consumption is not needed, preheating energy consumption is effectively reduced, and the low-temperature starting performance and operation stability of the compressor are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of thermal management technology for new energy vehicles, specifically to the preheating structure and control method for electric compressors in new energy vehicles. Background Technology

[0002] With the rapid development of the new energy vehicle industry, its performance in low-temperature environments has become a focus of industry attention. Electric compressors face severe challenges in low-temperature conditions (-30℃ and below). On the one hand, the viscosity of lubricating oil increases dramatically, significantly raising the frictional resistance between mechanical parts; simultaneously, material shrinkage at low temperatures further exacerbates mechanical resistance, making compressor start-up difficult and significantly increasing energy consumption. On the other hand, the refrigerant density decreases, severely reducing the compressor's volumetric efficiency and significantly weakening its performance. Traditional preheating solutions, such as those using PTC heaters, require a large amount of additional energy from the battery, with a single preheating cycle consuming 3-5 kWh, accounting for 15%-30% of the vehicle's low-temperature energy consumption. This is undoubtedly adding insult to injury for new energy vehicles whose range is already affected by low temperatures. As the new energy vehicle market continues to demand higher driving ranges, the development of efficient and energy-saving electric compressor preheating technology is urgently needed.

[0003] Currently, mainstream electric compressor preheating technologies have significant shortcomings. Capacitor-based heating solutions, such as the technology used in the electric compressor low-temperature preheating method and equipment (patent publication number CN114204850A), detect the temperature of the filter capacitor and set the heating current and time according to a lookup table. While this prevents capacitance decay at low temperatures to some extent, it only heats localized components of the capacitor and fails to effectively address core issues such as increased mechanical resistance and poor lubrication of the compressor body due to low temperatures. Furthermore, it has high energy consumption, reaching 2.5-4 kWh at -25°C. System-level thermal management solutions, such as the electric compressor control method, system, electronic equipment, and storage medium (patent publication number CN115782532A), control compressor speed by coordinating multiple parameters such as the evaporator, heater core, and battery pack water temperature. However, this solution relies on the overall operation of the air conditioning system and cannot provide targeted preheating of critical internal components, such as the suction chamber and oil circuit, before compressor startup. Moreover, the response delay exceeds 30 seconds, making it difficult to meet the demand for rapid and efficient preheating. More importantly, none of the existing technologies mentioned above have been able to effectively utilize the large amount of waste heat generated during the operation of the electric compressor itself. For example, the waste heat of the motor windings can exceed 80°C, and the waste heat of the exhaust refrigerant can reach 150°C, resulting in a huge waste of energy.

[0004] Addressing the numerous shortcomings of existing technologies, the core problem this invention aims to solve is: how to achieve efficient utilization and precise distribution of internal waste heat in an electric compressor through an innovative self-generated heat directional recovery mechanism and intelligent dynamic control strategy, thereby achieving rapid preheating with minimal energy consumption in low-temperature environments while effectively avoiding the risk of compressor overheating. Specifically, the following key technical challenges need to be overcome: First, designing an efficient coupling recovery path for motor waste heat and compressor waste heat to completely eliminate dependence on external high-energy-consuming preheating methods; second, constructing a dynamic heat demand matching mechanism for multiple temperature zones (oil circuit / suction chamber / shell) to solve the problem of insufficient preheating or heat redundancy caused by traditional fixed threshold control; and third, achieving seamless switching control between the preheating process and normal compressor operation to ensure stable and efficient compressor operation.

[0005] In summary, existing electric compressor preheating technologies for new energy vehicles have significant shortcomings in terms of energy consumption, preheating effect, and waste heat utilization. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of existing technologies by providing a preheating structure and control method for electric compressors in new energy vehicles. This method captures waste heat from the motor stator at 80-120℃ through an internal heat-conducting fin array, and recovers waste heat from the compressed refrigerant at 150-200℃ through a spiral flow channel covering the exhaust chamber. Both types of waste heat are then introduced into a shared heat transfer medium. A fuzzy PID controller dynamically adjusts the heat-conducting valve based on the lubricating oil temperature, suction superheat, and shell temperature to precisely distribute heat flow. At ultra-low temperatures (≤-40℃), a motor stall mode is triggered for rapid heating, combined with a thermal decay model to predict preheating needs and a paraffin-based phase change material for temperature stabilization. This solution eliminates the need for external high-energy-consumption heating, achieves efficient waste heat utilization, enables rapid preheating at ultra-low temperatures, effectively reduces energy consumption, avoids overheating risks, and improves the compressor's low-temperature start-up performance and operating efficiency.

[0007] To solve the above-mentioned technical problems, the present invention provides the following technical solution: A preheating control method for an electric compressor in a new energy vehicle, comprising the following steps: S100, co-processing heat source recovery: The heat-conducting fin array integrated inside the compressor captures the waste heat of 80-120℃ generated by the motor stator winding, and at the same time recovers the high-temperature refrigerant waste heat of 150-200℃ during the compression process through the spiral flow channel covering the exhaust chamber, and introduces the two types of heat sources into a shared heat transfer medium. S200, Dynamic Heat Demand Allocation: Real-time acquisition of lubricating oil circuit temperature, suction chamber refrigerant temperature, and compressor casing temperature; execution of the following control logic: When the temperature of the lubricating oil circuit is < -30℃, adjust the heat diversion valve to distribute 80% of the heat flow to the lubricating oil circuit; When the refrigerant superheat in the suction chamber is <5℃, adjust the heat diversion valve to distribute 70% of the heat flow to the suction chamber; When the compressor casing temperature exceeds 100℃, close the heat transfer valve to interrupt heat flow. S300, Self-starting Cooperative Execution: Under cold start conditions with ambient temperature ≤-40℃, the motor stall mode is triggered for ≤10 seconds, using Joule heat from the stator windings to raise the lubricating oil circuit temperature to above -30℃, then exiting the stall mode and starting the compression cycle.

[0008] Furthermore, the flow path of the shared heat transfer medium in step S100 satisfies: A variable thermal conductivity interface material is filled between the thermally conductive fin array and the motor stator, with a thermal conductivity of 0.5 at ≤80℃. At temperatures above 80℃, it rises to 3.0. ; A Helmholtz resonant cavity is installed on the inner wall of the spiral flow channel to suppress airflow noise in the 500-800Hz frequency band; The heat transfer medium switches its transmission direction via a reconfigurable flow channel driven by a shape memory alloy. When the oil temperature is <-30℃, it connects to the lubricating oil circuit, and when the intake superheat is <5℃, it switches to the intake chamber.

[0009] Furthermore, the dynamic allocation of heat demand in step S200 is achieved through a fuzzy PID controller, including: The input variable is the temperature deviation of the lubrication circuit. Intake superheat deviation , shell temperature deviation ,in: It is the difference between the actual lubrication circuit temperature and the target lubrication circuit temperature. It is the difference between the actual intake superheat and the target intake superheat value. It is the difference between the actual shell temperature and the target shell temperature. The output variable is the opening degree of the thermal flow guide valve. This is used to determine the opening degree of the heat diversion valve and adjust the heat flow distribution; The control rule base contains the following mapping relationships:

[0010] in, , For the proportional and integral control parameters of the fuzzy PID controller, for Integral over time;

[0011] in, , For the proportional and integral control parameters of the fuzzy PID controller, for Integral over time;

[0012] This rule is based on the heat resistance limit of the compressor housing material and is determined and executed by the controller's built-in protection logic.

[0013] Furthermore, the stall mode execution process in step S300 includes: The rotor is locked by applying a PWM wave with a duty cycle of 30%-50% through the motor controller; Real-time monitoring of winding temperature rise rate; forced disengagement of stall when temperature rise > 10℃ / s or duration > 10 seconds. After exiting the stall, delay for ≥0.5 seconds before injecting refrigerant to avoid liquid refrigerant impacting the compression chamber.

[0014] Furthermore, it also includes the following steps: After the compressor is shut down, the oil temperature and suction temperature at the next startup are predicted based on the thermal decay model, specifically: Oil temperature prediction value Determine as follows:

[0015] in: The ambient temperature of the compressor. The temperature of the lubricating oil circuit at the moment the compressor shuts down. This is the time interval between the compressor's shutdown time and the next scheduled startup time. The thermal decay coefficient; When the judgment At that time, the thermal guide valve is opened 10 minutes before the planned start time to perform the pre-lubrication oil circuit operation.

[0016] Furthermore, a paraffin-based phase change material unit with a phase change point of -20°C is embedded in the lubrication circuit, performing the following: When the oil temperature is <-20℃, it absorbs heat flow and stores latent heat. When the oil temperature drops by more than 15°C, latent heat is released to maintain a stable oil temperature.

[0017] Furthermore, the parameter tuning of the fuzzy PID controller aims to minimize the system entropy productivity, including: Real-time calculation of entropy production rate ,in: For oil circuit heat flow, For the temperature of the lubricating oil circuit, For the heat flow in the intake chamber, This refers to the temperature of the intake chamber. Iterative optimization using gradient descent method , Parameters, make Minimum, that is: ,in, The controller calculates the integral of the entropy production rate over time during the iteration process. ,Adjustment , Continue until the minimum requirement is met.

[0018] On the other hand, the preheating structure of the electric compressor for new energy vehicles includes: Temperature sensor group: includes a PT1000 probe mounted on the lubrication oil circuit, a T-type thermocouple in the suction chamber, and an NTC thermistor on the housing surface; Heat transfer valve: a three-way proportional valve, with the inlet connected to a shared heat transfer medium circuit, and the two outlets connected to the lubricating oil circuit and the suction chamber, respectively; Processor: Embedded MCU, storing the fuzzy PID control algorithm and thermal decay model, outputting PWM signal to drive the thermal diversion valve.

[0019] Compared with existing technologies, the preheating structure and control method for electric compressors in new energy vehicles have the following advantages: I. This invention integrates a heat-conducting fin array and a spiral flow channel to capture the waste heat of the motor stator winding at 80-120°C and the high-temperature refrigerant waste heat at 150-200°C during the compression process, forming a self-generated heat recovery path. It eliminates the need for external equipment such as PTC heaters, thus completely eliminating the need for additional electrical energy consumption. At the same time, the variable thermal conductivity interface material and shape memory alloy flow channel enable the directional transfer and efficient utilization of waste heat. Combined with a fuzzy PID controller to dynamically allocate heat flow, it avoids insufficient preheating or heat redundancy caused by traditional fixed threshold control. Compared with existing technologies, it effectively reduces preheating energy consumption and significantly improves energy utilization efficiency.

[0020] Second, this invention, through a self-starting collaborative strategy, triggers the motor stall mode when the ambient temperature is ≤-40℃, and uses Joule heating to raise the lubricating oil temperature to above -30℃ within 10 seconds, breaking through the bottleneck of ultra-low temperature start-up; the thermal decay model can predict the oil temperature for the next start-up and perform pre-lubrication operation 10 minutes in advance, shortening the start-up delay; the paraffin-based phase change material embedded in the lubricating oil circuit releases latent heat when the oil temperature drops sharply, maintaining viscosity stability and reducing the frictional resistance of mechanical parts; the protection logic of closing the thermal diversion valve when the shell temperature exceeds the limit effectively avoids the risk of overheating and ensures that the compressor starts smoothly and operates stably under low temperature conditions.

[0021] Other advantages, objectives and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination or study, or may be learned from the practice of the invention. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0023] Figure 1 This is a flowchart illustrating the operation of the present invention. Figure 2 This is a step diagram of the present invention; Figure 3 This is a framework diagram of the present invention. Detailed Implementation

[0024] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided below.

[0025] Example 1 This embodiment discloses a preheating structure and control method for an electric compressor in a new energy vehicle, aiming to solve the problems of difficult start-up, high energy consumption, and low waste heat utilization rate of electric compressors in low-temperature environments. Figure 2 and Figure 3 As shown, this scheme integrates a heat source collaborative recovery mechanism to capture waste heat from the motor stator windings and high-temperature refrigerant waste heat during compression, and introduces them into a shared heat transfer medium. Fuzzy PID control is used to dynamically allocate heat demand, precisely adjusting heat flow distribution based on lubricating oil temperature, suction superheat, and casing temperature. Combined with a self-starting collaborative execution strategy, a motor stall mode is triggered for rapid temperature rise under ultra-low temperature conditions, and preheating prediction and pre-operation are achieved through a thermal decay model. Simultaneously, structural optimizations such as variable thermal conductivity interface materials, Helmholtz resonant cavities, and shape memory alloy flow channels ensure efficient utilization of waste heat and stable system operation. This method can achieve rapid compressor preheating in environments of -40℃ and below, effectively reducing preheating energy consumption and significantly improving the compressor's start-up performance and operating efficiency under low-temperature conditions.

[0026] The preheating structure of the electric compressor for new energy vehicles in this embodiment mainly consists of a temperature sensor group, a heat diversion valve, a processor, and supporting heat recovery components. These components work together to achieve precise monitoring, control, and execution of the preheating process.

[0027] The temperature sensor array is responsible for collecting real-time temperature data from key components, providing a basis for control decisions. The PT1000 probe, mounted on the lubrication circuit, uses platinum resistance sensing, with its resistance changing linearly with temperature. Its measurement range covers -50℃ to 150℃, with an accuracy of ±0.1℃, accurately capturing temperature fluctuations in the lubrication circuit. The T-type thermocouple in the suction chamber is made of copper-constantan material, with a response time ≤0.5 seconds, enabling real-time monitoring of refrigerant superheat in the suction chamber. Its measurement range is -200℃ to 350℃, meeting the requirements of low-temperature preheating scenarios. The NTC thermistor on the housing surface has a negative temperature coefficient, with a resistance of 10kΩ at 25℃ and a temperature coefficient of -3% / ℃, allowing for rapid feedback of housing temperature changes and preventing overheating.

[0028] The heat diversion valve is a three-way proportional valve driven by a stepper motor. Its inlet connects to a shared heat transfer medium circuit, and its two outlets connect to the lubrication oil circuit and the suction chamber, respectively. The valve's opening range is 0-100%, with a control accuracy of ±2%. It continuously adjusts the heat flow distribution ratio by receiving a PWM signal output from the processor. When the heat diversion valve is open at 80%, it means that 80% of the heat flow enters the lubrication oil circuit and 20% enters the suction chamber; when the opening is 0%, heat flow transfer is completely interrupted, ensuring system safety.

[0029] The processor uses a 32-bit embedded MCU with a main frequency of 120MHz and a built-in 12-bit ADC module, which can simultaneously acquire three temperature sensor signals at a sampling frequency of 10Hz. The MCU pre-stores fuzzy PID control algorithms and thermal decay models. By processing the acquired temperature data, it generates thermal flow valve drive signals and motor stall control commands, realizing intelligent control of the preheating process.

[0030] Co-harvesting heat recovery captures waste heat through a dual-pathway system and optimizes the transmission path. The specific working process is as follows: In the waste heat recovery path of the motor stator, the compressor integrates an annular heat-conducting fin array. The fins are made of 6061 aluminum alloy, with a thickness of 0.5 mm and a spacing of 2 mm. They are tightly bonded to the motor stator core, with a contact area reaching 85% of the stator surface area. A variable thermal conductivity interface material is filled between the fins and the stator. This material uses silicone rubber as a matrix and incorporates graphene nanoparticles and phase change microcapsules. At temperatures ≤80℃, the phase change microcapsules do not undergo a phase change, and the graphene network inside the material is discontinuous, resulting in a thermal conductivity of only 0.5%. This prevents excessive heat loss during normal motor operation; when the temperature exceeds 80℃, the phase change microcapsules rupture to release graphene, forming a continuous heat-conducting network, and the thermal conductivity increases sharply to 3.0. It quickly transfers the 80-120℃ residual heat generated by the stator windings into a shared heat transfer medium.

[0031] In the high-temperature refrigerant waste heat recovery path during the compression process, the outer wall of the exhaust chamber is covered with a spiral flow channel made of 316 stainless steel. The channel has an inner diameter of 8mm, a pitch of 20mm, and a total length of 1.2m. The gap between the channel and the exhaust chamber is ≤0.1mm, and tight contact is achieved through welding. Helmholtz resonant cavities are evenly distributed on the inner wall of the spiral flow channel. Each resonant cavity consists of a cylindrical cavity with a diameter of 3mm and a connecting hole with a diameter of 1mm. The cavity depth is 5mm. Three cavities are evenly distributed at 120° intervals along the axial direction of the flow channel, arranged in groups of three every 50mm. The working principle utilizes the acoustic resonance system formed by the cavity and the connecting hole. When airflow noise in the 500-800Hz frequency band is introduced, the noise energy is dissipated within the resonant cavity, reducing the noise in this frequency band by 15-20dB, thus solving the noise problem in the waste heat recovery process. Through this spiral flow channel, the high-temperature refrigerant waste heat from the compression process at 150-200℃ can be effectively recovered and combined with the motor waste heat into a shared heat transfer medium.

[0032] The shared heat transfer medium is a 50% ethylene glycol aqueous solution with a freezing point as low as -35℃, preventing freezing at low temperatures. The flow path of the medium is controlled by a reconfigurable flow channel driven by a shape memory alloy. The shape memory alloy is made of Ni-Ti alloy wire with a diameter of 0.5mm and a phase transformation temperature of -30℃. When the oil temperature is <-30℃, the alloy wire is in the martensitic state, its length contracts, and it pulls the flow channel switching valve core to connect to the lubricating oil circuit. When the suction superheat is <5℃, the oil temperature is usually higher than -30℃, the alloy wire returns to the austenitic state, its length elongates, and it pushes the valve core to switch to the suction chamber passage, achieving adaptive adjustment of the heat flow direction.

[0033] The dynamic heat demand allocation module is based on a fuzzy PID controller. It dynamically adjusts the opening of the heat diversion valve by analyzing temperature deviations in real time to ensure accurate heat distribution. The specific working process is as follows: First, define the input and output variables. Input variables include the lubricating oil circuit temperature deviation. Intake superheat deviation , shell temperature deviation .in, It is the actual lubrication circuit temperature minus the target lubrication circuit temperature (the target temperature is set to -10℃ to ensure that the lubrication oil viscosity is within a reasonable range). It is the actual suction superheat minus the target suction superheat value (the target value is set to 8℃ to avoid refrigerant liquid slugging). This is the actual shell temperature minus the target shell temperature (the target value is set to 80℃, below the material's heat resistance limit of 100℃). The output variable is the opening degree of the thermal conductivity valve. The range is 0-100%, which directly determines the heat flow distribution ratio.

[0034] The control rule base is formulated based on different operating conditions, and its specific applications are as follows:

[0035] in, The initial value is set to 2.5. The initial value is set to 0.1. By accumulating the oil temperature deviation through the integral term, the valve opening is continuously increased to ensure that over 80% of the heat flow is directed to the lubrication circuit. For example, when the actual oil temperature is -40℃, At -30℃, the controller output opening quickly rises to 80%, accelerating the recovery of oil temperature.

[0036]

[0037] The initial value is set to 3.0. The initial value is set to 0.08, with a focus on adjusting the heat flow in the intake chamber. If the actual intake superheat is 3°C, At -5℃, the controller output opening directs 70% of the heat flow to the suction chamber, increasing the refrigerant temperature.

[0038]

[0039] The thermal deflection valve is closed to prevent the casing from being damaged by overheating deformation. This protection logic is implemented by the processor's built-in hardware interrupt, with a response time of ≤10ms.

[0040] To optimize control performance, the fuzzy PID controller parameter tuning aims to minimize the system's entropy productivity. (Entropy productivity) ,in: Heat flux in the oil circuit (unit: W). Temperature of the lubricating oil circuit (unit: K). Heat flux in the intake chamber (unit: W). The intake chamber temperature is represented in Kelvin. Entropy productivity reflects the irreversible loss in the heat transfer process; a smaller value indicates higher heat utilization efficiency. The controller is iteratively optimized using the gradient descent method. , The parameters are calculated in real time, with an iteration step size of 0.05. (Integral of entropy productivity over time) When the change in the integral value over 5 consecutive iterations is less than 0.1, optimization stops, at which point the parameters reach their optimal state. For example, in an environment of -30℃, after optimization... Adjusted to 2.8. Adjusting it to 0.12 can reduce the entropy production rate by 12%.

[0041] The self-starting collaborative execution module is designed for extreme low-temperature conditions, ensuring that the compressor can start smoothly in environments at -40℃ and below. The specific working process is as follows: When the ambient temperature sensor detects a temperature ≤-40℃, the processor triggers the motor stall mode. The motor controller applies a PWM wave with a duty cycle of 30%-50% to the stator windings, controlling the winding current between 50%-70% of the rated current by adjusting the duty cycle (to avoid overcurrent damage), thus locking the rotor from rotation. At this time, electrical energy is mainly converted into Joule heat in the stator windings. During the stall process, the winding temperature rises at a rate of 5-8℃ / s. The processor monitors the winding temperature rise rate in real time. When the temperature rise >10℃ / s (possibly due to a partial short circuit) or the duration >10 seconds, the PWM output is immediately cut off, forcibly exiting the stall mode to ensure motor safety.

[0042] After exiting the stall mode, refrigerant is injected through the electronic expansion valve after a delay of ≥0.5 seconds. This delay time is calculated based on the refrigerant flow rate to ensure that the lubricating oil is fully preheated and forms an oil film on the surface of mechanical parts, preventing liquid refrigerant from directly impacting the compression chamber and causing liquid slugging damage. This process allows the lubricating oil temperature to rise from -40℃ to above -30℃ within 10 seconds, meeting the basic lubrication requirements for compressor startup.

[0043] After the compressor shuts down, the processor predicts the oil temperature at the next startup based on a thermal decay model, providing a basis for preheating. (Predicted oil temperature value) ,in For ambient temperature, The oil temperature at the moment the compressor shuts down. The time interval between shutdown and the next scheduled startup. Thermal attenuation coefficient (at -30℃) =0.015 / s). When the predicted oil temperature is <-30℃, the heat diversion valve is opened 10 minutes before the planned start-up time to utilize the stored residual heat to perform pre-lubrication circuit operations, thus shortening the start-up preheating time.

[0044] The paraffin-based phase change material unit embedded in the lubricating oil circuit further enhances oil temperature stability. This unit adopts a sealed copper shell structure and is filled with n-octadecane paraffin with a phase change point of -20℃ and a latent heat of phase change of 240kJ / kg. When the oil temperature is <-20℃, the paraffin absorbs heat flow and changes from solid to liquid, storing latent heat. When the oil temperature drops sharply by more than 15℃ due to a sudden drop in ambient temperature or heat flow fluctuations, the paraffin changes from liquid to solid, releasing latent heat, slowing down the rate of oil temperature drop, and ensuring that the viscosity of the lubricating oil remains stable within a reasonable range. For example, when the ambient temperature drops sharply from -30℃ to -45℃, the latent heat released by the phase change material can reduce the oil temperature by only 8℃ within 5 minutes, preventing a sharp increase in viscosity.

[0045] This embodiment achieves efficient preheating of electric compressors for new energy vehicles in low-temperature environments by constructing a complete technical system encompassing heat source collaborative recovery, dynamic heat demand allocation, self-starting collaborative execution, and auxiliary stabilization. The heat source collaborative recovery module, through dual-path waste heat capture and intelligent flow channel switching, achieves efficient recovery and directional transmission of waste heat from 80-200℃, eliminating reliance on external high-energy-consuming preheating methods. The dynamic heat demand allocation module, based on fuzzy PID control and entropy yield optimization, achieves precise allocation of heat flow across multiple temperature zones, solving the problems of insufficient preheating or heat redundancy in traditional control. The self-starting collaborative execution module ensures rapid start-up under ultra-low temperature conditions of -40℃ through rapid heating from motor stall, heat decay model prediction, and pre-operation. The paraffin-based phase change material unit effectively improves oil temperature stability.

[0046] Example 2

[0047] like Figure 1 As shown in Example 1, this example elaborates on the specific steps of the preheating structure and control method for the electric compressor of a new energy vehicle. The specific steps are as follows: 1. Testing low-temperature environments When the ambient temperature sensor detects a temperature ≤-40℃, the system determines that it is in a cold start condition and starts the preheating program. 2. Capture motor waste heat The waste heat (80-120℃) generated by the motor stator winding is captured by the heat-conducting fin array inside the compressor. 3. Recovering waste heat from refrigerant The high-temperature refrigerant waste heat (150-200℃) generated during the compression process is recovered through a spiral flow channel covering the exhaust chamber. 4. Import shared heat transfer medium The waste heat from the motor and the waste heat from the refrigerant are jointly introduced into a circuit with a shared heat transfer medium (50% ethylene glycol aqueous solution); 5. Real-time temperature data acquisition The temperature of the lubrication circuit is collected using a PT1000 probe in the lubrication circuit. The temperature of the refrigerant in the suction chamber is collected using a T-type thermocouple in the suction chamber. The compressor housing temperature is collected using an NTC thermistor on the housing surface.

[0048] 6. Dynamically distribute heat flow (based on temperature conditions) Scenario A: If the lubricating oil circuit temperature is <-30℃, adjust the heat diversion valve to distribute 80% of the heat flow to the lubricating oil circuit; Scenario B: If the refrigerant superheat in the suction chamber is <5°C, adjust the heat diversion valve to distribute 70% of the heat flow to the suction chamber; Scenario C: If the compressor casing temperature > 100℃, close the heat transfer valve to interrupt heat flow. (Note: The priority of the above conditions is C>A>B, which is determined automatically by the processor.) 7. Execute stall mode (only when the ambient temperature is ≤-40℃) By applying a PWM wave with a duty cycle of 30%-50% to the motor controller, the rotor is locked and stalled. Real-time monitoring of winding temperature rise rate; if the temperature rise rate is >10℃ / s or the duration is >10 seconds, the stall mode is forcibly exited. 8. Exit stall and delay start. After exiting stall mode, there will be a delay of ≥0.5 seconds (to ensure that the lubricating oil forms an oil film). Inject refrigerant to start the compression cycle; 9. Phase change materials stabilize oil temperature When the temperature of the lubricating oil circuit is less than -20℃, the paraffin-based phase change material unit absorbs heat flow and stores latent heat. When the oil temperature drops by more than 15°C, the phase change material releases latent heat to maintain a stable oil temperature. 10. Preheating is anticipated after the compressor is shut down (optional, for use on the next startup). Predict the oil temperature at the next start-up based on the thermal decay model; If the predicted oil temperature is <-30℃, open the thermal guide valve to pre-lubricate the oil circuit 10 minutes before the planned start-up.

[0049] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A preheating control method for an electric compressor in a new energy vehicle, characterized in that, Includes the following steps: S100, co-processing heat source recovery: The heat-conducting fin array integrated inside the compressor captures the waste heat of 80-120℃ generated by the motor stator winding, and at the same time recovers the high-temperature refrigerant waste heat of 150-200℃ during the compression process through the spiral flow channel covering the exhaust chamber, and introduces the two types of heat sources into a shared heat transfer medium. S200, Dynamic Heat Demand Allocation: Real-time acquisition of lubricating oil circuit temperature, suction chamber refrigerant temperature, and compressor casing temperature; execution of the following control logic: When the temperature of the lubricating oil circuit is < -30℃, adjust the heat diversion valve to distribute 80% of the heat flow to the lubricating oil circuit; When the refrigerant superheat in the suction chamber is <5℃, adjust the heat diversion valve to distribute 70% of the heat flow to the suction chamber; When the compressor casing temperature exceeds 100℃, close the heat transfer valve to interrupt heat flow. S300, Self-starting Cooperative Execution: Under cold start conditions with ambient temperature ≤-40℃, the motor stall mode is triggered for ≤10 seconds, using Joule heat from the stator windings to raise the lubricating oil circuit temperature to above -30℃, then exiting the stall mode and starting the compression cycle.

2. The preheating control method for electric compressors in new energy vehicles according to claim 1, characterized in that, The flow path of the shared heat transfer medium in step S100 satisfies: A variable thermal conductivity interface material is filled between the thermally conductive fin array and the motor stator, with a thermal conductivity of 0.5 at ≤80℃. At temperatures above 80℃, it rises to 3.

0. ; A Helmholtz resonant cavity is installed on the inner wall of the spiral flow channel to suppress airflow noise in the 500-800Hz frequency band; The heat transfer medium switches its transmission direction via a reconfigurable flow channel driven by a shape memory alloy. When the oil temperature is <-30℃, it connects to the lubricating oil circuit, and when the intake superheat is <5℃, it switches to the intake chamber.

3. The preheating control method for electric compressors in new energy vehicles according to claim 1, characterized in that, The dynamic allocation of heat demand in step S200 is achieved through a fuzzy PID controller, including: The input variable is the temperature deviation of the lubrication circuit. Intake superheat deviation , shell temperature deviation ,in: It is the difference between the actual lubrication circuit temperature and the target lubrication circuit temperature. It is the difference between the actual intake superheat and the target intake superheat value. It is the difference between the actual shell temperature and the target shell temperature. The output variable is the opening degree of the thermal flow guide valve. This is used to determine the opening degree of the heat diversion valve and adjust the heat flow distribution; The control rule base contains the following mapping relationships: ； in, , For the proportional and integral control parameters of the fuzzy PID controller, for Integral over time; ； in, , For the proportional and integral control parameters of the fuzzy PID controller, for Integral over time; ； This rule is based on the heat resistance limit of the compressor housing material and is determined and executed by the controller's built-in protection logic.

4. The preheating control method for electric compressors in new energy vehicles according to claim 1, characterized in that, The stall mode execution process in step S300 includes: The rotor is locked by applying a PWM wave with a duty cycle of 30%-50% through the motor controller; Real-time monitoring of winding temperature rise rate; forced disengagement of stall when temperature rise > 10℃ / s or duration > 10 seconds. After exiting the stall, delay for ≥0.5 seconds before injecting refrigerant to avoid liquid refrigerant impacting the compression chamber.

5. The preheating control method for electric compressors in new energy vehicles according to claim 1, characterized in that, It also includes the following steps: After the compressor is shut down, the oil temperature and suction temperature at the next startup are predicted based on the thermal decay model, specifically: Oil temperature prediction value Determine as follows: ； in: The ambient temperature where the compressor is located. The temperature of the lubricating oil circuit at the moment the compressor shuts down. This is the time interval between the compressor's shutdown time and the next scheduled startup time. The thermal decay coefficient; When the judgment At that time, the thermal guide valve is opened 10 minutes before the planned start time to perform the pre-lubrication oil circuit operation.

6. The preheating control method for electric compressors in new energy vehicles according to claim 1, characterized in that, The lubrication circuit incorporates a paraffin-based phase change material unit with a phase change point of -20℃, and performs the following: When the oil temperature is <-20℃, it absorbs heat flow and stores latent heat. When the oil temperature drops by more than 15°C, latent heat is released to maintain a stable oil temperature.

7. The preheating control method for electric compressors in new energy vehicles according to claim 3, characterized in that, The parameter tuning of the fuzzy PID controller aims to minimize the system entropy productivity, including: Real-time calculation of entropy production rate ,in: For oil circuit heat flow, For the temperature of the lubricating oil circuit, For the heat flow in the intake chamber, This refers to the temperature of the intake chamber. Iterative optimization using gradient descent method , Parameters, make Minimum, that is: ,in, The controller calculates the integral of the entropy production rate over time during the iteration process. ,Adjustment , Continue until the minimum requirement is met.

8. A preheating structure for an electric compressor in a new energy vehicle, applicable to the preheating control method for an electric compressor in a new energy vehicle as described in any one of claims 1-7, characterized in that, include: Temperature sensor group: includes a PT1000 probe mounted on the lubrication oil circuit, a T-type thermocouple in the suction chamber, and an NTC thermistor on the housing surface; Heat transfer valve: a three-way proportional valve, with the inlet connected to a shared heat transfer medium circuit, and the two outlets connected to the lubricating oil circuit and the suction chamber, respectively; Processor: Embedded MCU, storing the fuzzy PID control algorithm and thermal decay model, outputting PWM signal to drive the thermal diversion valve.

Images