Motor active heating control method and device based on phase change material and automobile

Abstract

The invention discloses a motor active heating control method and device based on a phase-change material and an automobile. The motor is made to run at the optimal efficiency by adjusting the d-axis and q-axis current proportion of the motor, generated waste heat is transmitted to a water path through a stator winding, latent heat is stored through the phase-change material, and heat is supplied to components such as a battery through a circulating water path. The heat demand is dynamically corrected through the two-dimensional influence coefficient table, locked-rotor heating or closed-loop control algorithm flow regulation is implemented in combination with the running state of the vehicle, and power output and heat demand balance is achieved. The device comprises a heat-insulated spiral waterway phase change container, an integrated sensor network and an intelligent control unit, works cooperatively with a heat pump system, and preferentially adopts waste heat of a motor for heating. Motor loss heat recovery and a phase change energy storage technology are combined, the problem that the battery heating efficiency of a new energy automobile is low in a low-temperature environment is solved, meanwhile, the uniform heat conduction characteristic of a phase change material is ensured through a porous framework structure, and stable constant-temperature control is achieved.

Description

Technical Field

[0001] The present invention belongs to the field of vehicle motor control, and in particular relates to a motor active heating control method and device based on phase change materials and a vehicle. Background Art

[0002] From the perspective of the development of new energy vehicles in my country, the technical direction and trend of new energy vehicles are unshakable. New energy vehicles, especially electric vehicles, mainly use power batteries as their power source, which can directly have a great impact on the power performance and cruising range of the vehicle. Its charge and discharge characteristics are greatly affected by temperature. The capacity retention rate of lithium batteries is 60%-70% at 0°C, 40%-55% at -10°C, and 20%-40% at -20°C. It can be seen that different temperatures have a great impact on the capacity retention rate of the battery. The lower the temperature of the electric vehicle, the shorter the cruising range. Therefore, in a low temperature environment, the battery pack needs to be heated to improve the charge and discharge performance of the battery.

[0003] At present, the heating solutions for pure electric vehicles in the market include: PTC heating and heat pump technology. With the improvement of performance requirements for electric vehicles, heat pump technology has become a research hotspot due to its efficient heating. The heat pump absorbs heat outside the car through the refrigerant circulation and releases it into the car to achieve the temperature rise inside the car. However, the performance of the heat pump is limited at low temperatures, and heating elements such as PTC are needed to supplement the heating. Although this improves the heating effect, it increases the cost and weight, and the heat generated by the motor is not fully utilized, resulting in increased power consumption. Therefore, it has become a new technical trend to generate appropriate heating power through motor control and actively heat the relevant components of electric vehicles. Summary of the invention

[0004] The purpose of the present invention is to overcome the above problems existing in the prior art and to provide a method, device and automobile for active heating control of a motor based on phase change materials.

[0005] In order to achieve the above technical objectives and the above technical effects, the present invention is implemented through the following technical solutions:

[0006] A motor active heating control method based on phase change material, comprising:

[0007] Adjusting the d-axis current and the q-axis current of the motor so that the driving efficiency of the motor deviates from the optimal efficiency output to generate heat;

[0008] The heat is transferred to the water path beside the motor through the stator winding, and the heat is transported to the phase change material container through the water path circulation;

[0009] The heat transferred by the water channel is stored by utilizing the phase change latent heat characteristics of the phase change material, and when the temperature of the phase change material reaches a preset threshold, the heated water is transported to the cooling device of the new energy vehicle through a water pump to achieve active heating of specific parts;

[0010] According to the vehicle operation status and environmental parameters, the heat demand power is dynamically adjusted, and the theoretical heat demand value is corrected in real time through a two-dimensional table based on the influence coefficient of the phase change material temperature and the water temperature of the water channel;

[0011] Monitor battery temperature, ambient temperature and motor operating temperature in real time, and trigger or terminate the heating process based on preset temperature control logic.

[0012] Furthermore, the phase change material is preferably paraffin or molten salt.

[0013] Furthermore, the specific steps of dynamically adjusting the heat demand power include:

[0014] When the vehicle is stationary, the locked-rotor heating method is used to fully allocate the motor output power to the heat demand power;

[0015] When the vehicle is in operation, based on the mechanical speed, load torque and electromagnetic torque requirements, the ratio of the d-axis current to the q-axis current is adjusted to generate the preset heating power while meeting the power requirements.

[0016] Furthermore, a closed-loop control algorithm is introduced in the process of dynamically adjusting the heat demand power, and the adjustment amplitude of the d-axis current is corrected in real time according to the temperature deviation to balance the power output and the heat demand.

[0017] Furthermore, an overheat protection mechanism is provided, and when it is detected that the temperature of the phase change material exceeds 60°C, the motor heating is automatically cut off and a cooling cycle is started.

[0018] The present invention also provides a motor active heating device based on phase change material, comprising:

[0019] A drive motor module is used to adjust the d-axis current and the q-axis current to generate controllable heating power;

[0020] A phase change material container is connected to the water path beside the motor and is used to store and release the latent heat of phase change;

[0021] A thermal circuit system, including a water pump, a heat sink and a circulating water circuit, for delivering water heated by the phase change material to the battery;

[0022] A control unit is used to dynamically adjust the heat output according to the vehicle operation status, the phase change material temperature and the water temperature of the water channel through a pre-calibrated system loss table and a two-dimensional influence coefficient table;

[0023] The temperature sensor and flow sensor integrated in the thermal circuit system are used to collect water temperature, flow rate and phase change material temperature data in real time and feed them back to the control unit.

[0024] Furthermore, the control unit has a built-in motor system loss table, and the loss table is generated by calibrating the functional relationship between motor current, voltage, torque and heat generation;

[0025] The two-dimensional influence coefficient table is generated by experimental calibration or machine learning algorithm optimization, specifically: under different combinations of ambient temperature and water temperature, the attenuation ratio of the phase change material to the heat demand is measured and fitted into the numerical relationship between K1 and K2.

[0026] Furthermore, the phase change material container is wrapped with a heat insulation layer and is provided with a spiral water channel inside to prolong the heat exchange time between water and the phase change material.

[0027] The present invention also provides a new energy vehicle, comprising:

[0028] The above-mentioned phase change material-based motor active heating device to achieve efficient thermal management of the battery in low temperature environments;

[0029] The device works in conjunction with the vehicle's heat pump system. When the ambient temperature is 10°C lower, the motor is started for active heating first, and the PTC and heat pump system serve as auxiliary heating units.

[0030] Furthermore, the installation position of the phase change material container is independent of the heat-requiring component, and the heat loss is reduced by the heat insulation layer;

[0031] The heat-requiring components are provided with heat-conducting plates, which are connected to the heat dissipation device through heat pipes to achieve uniform heat distribution.

[0032] The beneficial effects of the present invention are:

[0033] The present invention combines the heat recovery of motor loss with phase change energy storage technology, solving the problem of low battery heating efficiency in low-temperature environments of new energy vehicles. At the same time, the porous skeleton structure ensures the uniform thermal conductivity of the phase change material and achieves stable constant temperature control. The heat generated by the motor is fully utilized to effectively reduce power consumption; by adjusting the d and q axis currents to deviate from the optimal efficiency circle, the heat and power requirements of the vehicle are met at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0035] Figure 1 is a flow chart of the method of the present invention;

[0036] Figure 2 It is the logic diagram of the active heating state of the motor in the present invention;

[0037] Figure 3 It is the d-axis and q-axis current correction diagram of the driving motor in the present invention.

[0038] Figure 4 It is a correction logic diagram of the influence coefficient on the system in the present invention.

[0039] Figure 5 It is a schematic diagram of the structure of the phase change material container in the present invention. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] like Figure 1 The active heating control method of a motor based on phase change material shown in the figure specifically comprises the following steps:

[0042] Step 1: Adjust the d-axis current and q-axis current of the motor so that the driving efficiency of the motor deviates from the optimal efficiency output to generate heat.

[0043] Step 2: The heat is transferred to the water path beside the motor through the stator winding, and the heat is transported to the phase change material container through the water path circulation.

[0044] Among them, the phase change material is preferably paraffin or molten salt.

[0045] The heat transfer process of the phase change material container includes:

[0046] The phase change material continues to absorb heat from the water channel during the heat absorption stage until its temperature reaches equilibrium with the water temperature;

[0047] After the motor stops supplying heat, the phase change material releases the stored latent heat, heats the water in the water path, and controls the temperature of the heat-requiring parts through the heat dissipation device;

[0048] A porous skeleton structure is arranged in the phase change material container to enhance the thermal conductivity uniformity of the composite phase change material.

[0049] Step three: utilize the phase change latent heat characteristics of the phase change material to store the heat transferred by the water channel, and when the temperature of the phase change material reaches a preset threshold, the heated water is transported to the new energy vehicle cooling device through a water pump to achieve active heating of specific parts.

[0050] Step 4: Dynamically adjust the heat demand power according to the vehicle operating status and environmental parameters, and combine the influence coefficient of phase change material temperature and water temperature in the water channel to correct the theoretical heat demand value in real time through a two-dimensional table.

[0051] The specific steps of dynamically adjusting the heat demand power include:

[0052] When the vehicle is stationary, the locked-rotor heating method is used to fully allocate the motor output power to the heat demand power;

[0053] When the vehicle is in operation, based on the mechanical speed, load torque and electromagnetic torque requirements, the ratio of the d-axis current to the q-axis current is adjusted to generate the preset heating power while meeting the power requirements.

[0054] A closed-loop control algorithm is introduced in the process of dynamically adjusting the heat demand power, and the adjustment amplitude of the d-axis current is corrected in real time according to the temperature deviation to balance the power output and heat demand.

[0055] Step 5: Monitor the battery temperature, ambient temperature and motor operating temperature in real time, and trigger or terminate the heating process based on the preset temperature control logic.

[0056] As a preferred embodiment of the present invention, an overheat protection mechanism can be set up. When it is detected that the temperature of the phase change material exceeds 60° C., the motor heating is automatically cut off and a cooling cycle is started.

[0057] like Figure 2 As shown, the judgment logic of active heating of the motor is as follows: first, the temperature of the component requiring heating should be judged. If the temperature is lower than 10°C, the motor is started to actively heat, otherwise it enters the normal operating state; secondly, the vehicle operating state should be judged. If the vehicle is stationary, the motor enters the stalled state. At this time, all electrical energy will be converted into thermal energy to meet the heat demand of relevant components of the vehicle; if the vehicle is in motion, the motor enters the active reduced efficiency heating state, adaptively deviating from the optimal efficiency circle in order to meet both heat demand and power demand.

[0058] like Figure 3As shown in the figure, the calculation process of d-axis current and q-axis current is as follows. First, the mechanical speed, load torque and d-axis and q-axis voltages that meet the power demand are collected. Since the power demand is expressed by electromagnetic torque and it is strongly related to the d-axis and q-axis currents, the required electromagnetic torque is first formed by the mechanical speed and load torque. Then, the d-axis and q-axis currents under the best efficiency are obtained through the mechanical speed and the two-axis voltages. At this time, there is a loss table in the motor, and the loss table should be generated by calibrating the functional relationship between the motor current, voltage, torque and heat generation. At the same time, the control unit inputs the actual required heating power. By looking up the table, the d-axis current is adjusted to meet the heat demand. At the same time, since the electromagnetic torque has not changed, the q-axis current output can be dynamically adjusted in real time through the closed-loop control system to meet the power demand of the vehicle. At this point, after adjusting the d-axis and q-axis currents, they deviate from the best efficiency circle, and at the same time meet the heat demand and power demand of the vehicle.

[0059] The present invention also provides a motor active heating device based on phase change material, comprising:

[0060] The drive motor module is used to adjust the d-axis current and the q-axis current to generate controllable heating power.

[0061] The phase change material container is connected to the water channel beside the motor and is used to store and release the latent heat of phase change. The phase change material container is wrapped with a heat insulation layer and has a spiral water channel inside to extend the heat exchange time between water and the phase change material.

[0062] A thermal circuit system, including a water pump, a heat sink and a circulating water circuit, for delivering water heated by the phase change material to the battery;

[0063] The control unit is used to dynamically adjust the heat output through a pre-calibrated system loss table and a two-dimensional influence coefficient table according to the vehicle's operating status, the phase change material temperature, and the water temperature of the water circuit. The control unit has a built-in motor system loss table, which is generated by calibrating the functional relationship between the motor current, voltage, torque, and heat output; the two-dimensional influence coefficient table is generated through experimental calibration or machine learning algorithm optimization, specifically: under different combinations of ambient temperature and water temperature, the attenuation ratio of the phase change material's heat demand is measured and fitted into the numerical relationship between K1 and K2.

[0064] The temperature sensor and flow sensor integrated in the thermal circuit system are used to collect water temperature, flow rate and phase change material temperature data in real time and feed them back to the control unit.

[0065] like Figure 4As shown, the influence of the influence coefficient on the heating power is as follows. First, the temperature sensor and phase change material temperature sensor integrated in the thermal circuit system are used to collect water temperature, flow rate and phase change material temperature data in real time, and feed them back to the control unit. Then, due to the different attenuation ratios of the phase change material to the heat demand under different ambient temperature and water temperature combinations, the two-dimensional influence coefficient table (K1, K2) should be generated through experimental calibration or machine learning algorithm optimization, and the corresponding numerical relationship K is formed, and the control unit is built in. The influence coefficient is combined with the theoretical required heating power to form the final actual required heating power as the final value to be added to the q-axis current calculation.

[0066] like Figure 5 As shown, this embodiment provides a composite phase change material heat storage container, the phase change material is paraffin or molten salt, and the structure adopts a porous skeleton structure, which increases the contact area of ​​the heat transfer medium, ensures uniform heat distribution and avoids local overheating. The internal spiral water channel prolongs the heat exchange time, and the vacuum insulation layer reduces heat loss to the outside, thereby improving energy storage efficiency.

[0067] The present invention also provides a new energy vehicle, comprising:

[0068] The above-mentioned phase change material-based motor active heating device to achieve efficient thermal management of the battery in low temperature environments;

[0069] The device works in conjunction with the vehicle's heat pump system. When the ambient temperature is 10°C lower, the motor is started for active heating first, and the PTC and heat pump system serve as auxiliary heating units.

[0070] Wherein, the installation position of the phase change material container is independent of the heat-requiring component, and the heat loss is reduced by the heat insulation layer;

[0071] The heat-requiring components are provided with heat-conducting plates, which are connected to the heat dissipation device through heat pipes to achieve uniform heat distribution.

[0072] New energy vehicles also include transmission systems and thermal management systems:

[0073] In the transmission system, the motor outputs power through the reducer. In addition to the output of electrical energy as mechanical energy, the remaining part is converted into heat energy and transferred to the water jacket connected to the motor. At the same time, a spiral water channel is provided inside the water jacket to extend the heat exchange time, and heat is transferred to the phase change material container to send the heat generated by the motor into the vehicle thermal management system, realizing the coupling effect of the motor thermal energy and the thermal management system.

[0074] The vehicle thermal management system is a combination of the motor thermal management system, the cabin thermal management system and the battery thermal management system, including components such as the motor water jacket, PTC heater, electronic water pump, heat exchanger and three-way valve. When working, the motor generates heat, which is transported to the phase change material container through the water jacket and then enters the water cycle. The three-way valve adjusts the proportion of heat entering the cabin thermal management system and the battery thermal management system. The electrical energy output by the DC / DC converter is directly transmitted to the PTC heater to generate heat energy, which is then transmitted to the cabin thermal management system and the battery thermal management system. The water pump ensures the normal flow of coolant in the water circuit. The heat generated by the cabin thermal management system and the battery thermal management system is sent to the cabin and battery through the heat exchanger.

[0075] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0076] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the present invention to be protected.

Claims

1. A motor active heating control method based on phase change material, characterized in that: include: Adjusting the d-axis current and the q-axis current of the motor so that the driving efficiency of the motor deviates from the optimal efficiency output to generate heat; The heat is transferred to the water path beside the motor through the stator winding, and the heat is transported to the phase change material container through the water path circulation; The heat transferred by the water channel is stored by utilizing the phase change latent heat characteristics of the phase change material, and when the temperature of the phase change material reaches a preset threshold, the heated water is transported to the cooling device of the new energy vehicle through a water pump to achieve active heating of specific parts; According to the vehicle operation status and environmental parameters, the heat demand power is dynamically adjusted, and the theoretical heat demand value is corrected in real time through a two-dimensional table based on the influence coefficient of the phase change material temperature and the water temperature of the water channel; Monitor battery temperature, ambient temperature and motor operating temperature in real time, and trigger or terminate the heating process based on preset temperature control logic.

2. The method for controlling active heating of a motor based on phase change materials according to claim 1, characterized in that: The phase change material is preferably paraffin or molten salt.

3. The method for controlling active heating of a motor based on phase change material according to claim 1, characterized in that: The specific steps of dynamically adjusting the heat demand power include: When the vehicle is stationary, the locked-rotor heating method is used to fully allocate the motor output power to the heat demand power; When the vehicle is in operation, based on the mechanical speed, load torque and electromagnetic torque requirements, the ratio of the d-axis current to the q-axis current is adjusted to generate the preset heating power while meeting the power requirements.

4. The method for controlling active heating of a motor based on phase change material according to claim 3, characterized in that: A closed-loop control algorithm is introduced in the process of dynamically adjusting the heat demand power, and the adjustment amplitude of the d-axis current is corrected in real time according to the temperature deviation to balance the power output and the heat demand.

5. A motor active heating control method based on phase change material according to any one of claims 1 to 4, characterized in that: An overheat protection mechanism is set up. When it is detected that the phase change material temperature exceeds 60°C, the motor heating is automatically cut off and the cooling cycle is started.

6. A motor active heating device based on phase change material, characterized in that: include: A drive motor module is used to adjust the d-axis current and the q-axis current to generate controllable heating power; A phase change material container is connected to the water path beside the motor and is used to store and release the latent heat of phase change; A thermal circuit system, including a water pump, a heat sink and a circulating water circuit, for delivering water heated by the phase change material to the battery; A control unit is used to dynamically adjust the heat output according to the vehicle operation status, the phase change material temperature and the water temperature of the water channel through a pre-calibrated system loss table and a two-dimensional influence coefficient table; The temperature sensor and flow sensor integrated in the thermal circuit system are used to collect water temperature, flow rate and phase change material temperature data in real time and feed them back to the control unit.

7. The motor active heating device based on phase change material according to claim 6, characterized in that: The control unit has a built-in motor system loss table, which is generated by calibrating the functional relationship between motor current, voltage, torque and heat generation; The two-dimensional influence coefficient table is generated by experimental calibration or machine learning algorithm optimization, specifically: under different combinations of ambient temperature and water temperature, the attenuation ratio of the phase change material to the heat demand is measured and fitted into the numerical relationship between K1 and K2.

8. The motor active heating device based on phase change material according to claim 6, characterized in that: The phase change material container is wrapped with a vacuum insulation layer and is provided with a spiral water channel inside to prolong the heat exchange time between water and the phase change material.

9. A new energy vehicle, characterized in that: include: An active motor heating device based on phase change material as described in any one of claims 6 to 8 to achieve efficient thermal management of batteries in low temperature environments; The device works in conjunction with the vehicle's heat pump system. When the ambient temperature is 10°C lower, the motor is started for active heating first, and the PTC and heat pump system serve as auxiliary heating units.

10. A new energy vehicle according to claim 9, characterized in that: The installation position of the phase change material container is independent of the heat-requiring components, and the heat loss is reduced through the heat insulation layer; The heat-requiring components are provided with heat-conducting plates, which are connected to the heat dissipation device through heat pipes to achieve uniform heat distribution.

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