Thermal balancing control method, apparatus and voltage conversion system

Abstract

Embodiments of the present application provide a heat balance control method, device and voltage conversion system. The method comprises: monitoring the temperature of a plurality of heat source points in real time; determining whether the heat imbalance of the heat spreader occurs according to the temperature of the plurality of heat source points; if the heat imbalance occurs, controlling the power conversion unit to enter the heat balance adjustment mode to change the switching loss of the target power element, so that the heat spreader returns to the heat balance state; the target power element is the power element corresponding to the position area of the heat source point where the heat imbalance occurs. The method is used to efficiently achieve the heat balance of the equipment heating without affecting the electrical performance of the equipment, thereby realizing the efficient heat dissipation effect of the heat spreader.

Description

Technical Field

[0001] This application relates to the field of vehicle control technology, and in particular to a thermal equalization control method, device and voltage conversion system. Background Technology

[0002] As power electronic devices evolve towards higher power density and miniaturization, their heat dissipation performance faces increasingly higher demands. Traditional cooling methods, such as air cooling and liquid cooling, which rely on forced convection, are limited by fluid velocity and heat exchange area, making them unsuitable for high heat flux density applications. While vapor chambers offer significantly higher heat transfer efficiency than traditional solutions, their performance is extremely sensitive to the uniformity of the heat source temperature and is easily affected by localized hot spots.

[0003] In the common heat dissipation process of power electronic equipment that relies on heat exchangers, the heat generation of the power electronic equipment is usually regulated by methods such as derating, shutting down, or adjusting the fluid flow rate after the temperature at a certain point on the heat exchanger is detected to exceed the standard. However, this method is not only slow to take effect, but also cannot fundamentally solve the core problem of uneven spatial distribution of heat source power. This may lead to local drying of the heat exchanger and a sharp drop in heat transfer efficiency. Furthermore, thermal balance control through crude regulation methods such as derating and shutting down will also sacrifice the electrical performance of the power electronic equipment. Summary of the Invention

[0004] This application provides a thermal balance control method, device, and voltage conversion system to achieve efficient thermal balance of equipment heating without affecting the electrical performance of the equipment.

[0005] In a first aspect, embodiments of this application provide a thermal equilibrium control method applied to a voltage conversion system. The voltage conversion system includes a power conversion unit and a heat spreader. The power conversion unit includes multiple power elements, which are distributed in different locations on the heat spreader and are all thermally connected to the heat spreader. The heat spreader includes multiple heat source points distributed in different locations.

[0006] The thermal equilibrium control method includes:

[0007] Real-time monitoring of the temperature of multiple heat source points;

[0008] Based on the temperatures of the multiple heat source points, determine whether the heat spreader exhibits thermal imbalance.

[0009] If thermal imbalance occurs, the power conversion unit is controlled to enter the thermal balance adjustment mode to change the switching loss of the target power element and restore the heat spreader to the thermal balance state; the target power element is the power element corresponding to the location of the heat source point where thermal imbalance occurs.

[0010] In one possible implementation, the method further includes:

[0011] When the heat exchanger returns to thermal equilibrium, the power conversion unit is controlled to switch to steady-state high-efficiency mode, where the total loss of the power conversion unit is minimized.

[0012] In one possible implementation, the power conversion unit includes a primary-side power circuit and a secondary-side power circuit;

[0013] Before the real-time monitoring of the temperature of the multiple heat source points, the method further includes:

[0014] The primary-side power circuit and the secondary-side circuit are pre-defined to have multiple controllable freewheeling modes.

[0015] A total loss model of the power conversion unit is established, including the conduction loss and switching loss of each power element in the primary power circuit and the conduction loss and switching loss of each power element in the secondary power circuit. The total loss is decomposed and mapped to the heat source points in different locations on the heat spreader plate.

[0016] For different electrical operating conditions of the power conversion unit, a multi-objective control strategy is established with different loss distributions as the optimization objective. The multi-objective control strategy includes the correspondence between control parameters and controllable freewheeling modes under different electrical operating conditions. The control parameters include switching frequency, primary duty cycle, secondary duty cycle and phase shift angle.

[0017] In one possible implementation, the step of decomposing and mapping the total loss to heat source points in different locations on the heat spreader plate includes:

[0018] The total loss is decomposed and mapped to the corresponding primary side upper bridge arm heat source point, primary side lower bridge arm heat source point, secondary side upper bridge arm heat source point, and secondary side lower bridge arm heat source point on the heat spreader plate.

[0019] The losses of the primary side upper bridge arm heat source points consist of the conduction losses and switching losses of the primary side upper bridge arm power elements; the losses of the primary side lower bridge arm heat source points consist of the conduction losses and switching losses of the primary side lower bridge arm power elements; the losses of the secondary side upper bridge arm heat source points consist of the conduction losses and switching losses of the secondary side upper bridge arm power elements; and the losses of the secondary side lower bridge arm heat source points consist of the conduction losses and switching losses of the secondary side lower bridge arm power elements.

[0020] The real-time monitoring of the temperature of multiple heat source points includes:

[0021] The temperatures of the primary side upper arm heat source point, the primary side lower arm heat source point, the secondary side upper arm heat source point, and the secondary side lower arm heat source point are monitored in real time.

[0022] In one possible implementation, the multiple controllable freewheeling modes of the primary-side power circuit and the secondary-side power circuit all include an alternating freewheeling mode with equal distribution between the upper and lower transistors, a freewheeling mode with only the upper transistor, and a freewheeling mode with only the lower transistor. In one possible implementation, determining whether the heat spreader exhibits thermal imbalance based on the temperatures of the multiple heat source points includes:

[0023] Calculate the average temperature of the multiple heat source points;

[0024] Calculate the difference between the temperature of the plurality of heat sources and the average value;

[0025] If the difference is greater than a preset threshold, then the heat spreader will experience thermal imbalance at the heat source point.

[0026] In one possible implementation, determining whether the heat spreader exhibits thermal imbalance based on the temperatures of the plurality of heat source points includes:

[0027] Calculate the temperature rise gradient at each of the aforementioned heat source points;

[0028] Based on the temperature rise gradient, determine whether the corresponding heat source point experiences thermal imbalance;

[0029] If the temperature rise gradient is greater than a preset gradient threshold, then thermal imbalance occurs at the corresponding heat source point.

[0030] In one possible implementation, controlling the power conversion unit to enter a thermal equilibrium adjustment mode to change the switching losses of the target power element and restore the heat spreader to a thermal equilibrium state includes:

[0031] Based on the location of the heat source and the direction of the temperature difference corresponding to the thermal imbalance, a controllable freewheeling mode and control parameters that cause the power element corresponding to the heat source to bear less or more losses under the current electrical operating conditions are selected from the pre-established multi-objective control strategy. The control strategy of the power conversion unit is adjusted according to the selected controllable freewheeling mode and control parameters. Specifically, if the direction of the temperature difference indicates that the temperature of the heat source is too high, a control strategy that causes the power element corresponding to the heat source to bear less losses is selected; otherwise, a control strategy that causes the power element corresponding to the heat source to bear more losses is selected.

[0032] Secondly, embodiments of this application provide a thermal equalization control device applied to a voltage conversion system. The voltage conversion system includes a power conversion unit and a heat spreader. The power conversion unit includes multiple power elements distributed in different locations on the heat spreader and all thermally connected to the heat spreader. The heat spreader includes multiple heat source points distributed in different locations. The device includes:

[0033] The detection module is used to monitor the temperature of multiple heat source points in real time;

[0034] The judgment module is used to determine whether the heat spreader has thermal imbalance based on the temperature of the multiple heat source points.

[0035] The control module is used to control the power conversion unit to enter the thermal balance adjustment mode if thermal imbalance occurs, so as to change the switching loss of the target power element and restore the heat spreader to the thermal balance state; the target power element is the power element corresponding to the location of the heat source point where thermal imbalance occurs.

[0036] Thirdly, embodiments of this application provide a voltage conversion system, the voltage conversion system including a power conversion unit and a heat spreader; the power conversion unit includes multiple power elements, the multiple power elements are distributed in different positions on the heat spreader and are all thermally connected to the heat spreader, the heat spreader includes multiple heat source points distributed in different positions; the voltage conversion system is used to employ the methods described in the first aspect and / or various possible implementations of the first aspect.

[0037] The thermal equalization control method, device, and voltage conversion system provided in this application monitor the heat distribution of multiple components in the power conversion unit in real time through multi-point temperature acquisition. They proactively determine the thermal equalization and dynamically adjust the control strategy to fundamentally address the lag in thermal equalization assessment inherent in traditional heat dissipation methods. This effectively prevents the formation of localized hot spots on the surface of the heat exchanger due to uneven loss distribution in power devices, thus preventing a vicious cycle of localized drying and decreased phase change heat transfer efficiency in the heat exchanger. Ultimately, this achieves efficient heat dissipation from the heat exchanger. Furthermore, this thermal equalization control method employs an active, proactive thermal management approach, eliminating the need for passive derating or shutdown after detecting excessive temperatures. This ensures both the heat dissipation performance of the power conversion unit and its electrical output capability, thereby guaranteeing the reliability, stability, and continuous output capability of the voltage conversion system. Attached Figure Description

[0038] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0039] Figure 1 This application provides a schematic diagram of the structure of a voltage conversion system;

[0040] Figure 2 A schematic flowchart of a thermal equilibrium control method provided in this application;

[0041] Figure 3 This application provides a schematic diagram of the structure of a power conversion unit;

[0042] Figure 4 A schematic diagram of the operating waveforms of the primary power circuit and the secondary power circuit of a power conversion unit provided in this application when the operating voltage is in two different states;

[0043] Figure 5 A schematic diagram of the working waveforms of multiple power elements in the secondary power circuit of a power conversion unit provided in this application under different controllable freewheeling modes;

[0044] Figure 6 This application provides a schematic diagram of the structure of a thermal equilibrium control device.

[0045] Figure 7 A schematic diagram of another thermal equilibrium control device provided in this application;

[0046] Figure 8 This is a schematic diagram of the structure of an electronic device provided in this application.

[0047] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0048] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0049] like Figure 1 As shown, this application provides a voltage conversion system 100, which includes a power conversion unit 110 and a heat spreader 120.

[0050] The power conversion unit 110 includes multiple power elements, which are distributed in different locations on the heat spreader 120 and are all thermally connected to the heat spreader 120. The heat spreader 120 includes multiple heat source points distributed in different locations.

[0051] It should be noted that the power conversion unit 110 refers to a hardware collection capable of converting electrical energy, such as a circuit board or modular structure that includes a transformer, primary power circuit, secondary power circuit and various power devices.

[0052] The primary power circuit is the circuit part on the input side of the power conversion unit 110, which is responsible for receiving the input voltage and driving the power conversion. The secondary power circuit is the circuit part on the output side of the power conversion unit 110, which is responsible for outputting the converted electrical energy to the load. The transformer is responsible for electrical isolation and energy transfer.

[0053] Specifically, the primary-side bridge arm in the primary-side power circuit included in the power conversion unit 110 can be divided into primary-side upper bridge arm power elements and primary-side lower bridge arm power elements.

[0054] The primary-side upper arm power element includes a primary-side switching device located in the upper arm of the primary-side power circuit, and the primary-side lower arm power element includes a primary-side switching device located in the lower arm of the primary-side power circuit. The primary-side switching device can be a power switching transistor.

[0055] The secondary bridge arm in the secondary power circuit can be divided into the upper secondary bridge arm power element and the lower secondary bridge arm power element.

[0056] The secondary-side upper arm power element includes a secondary-side switching device located in the upper arm of the secondary-side power circuit, and the secondary-side lower arm power element includes a secondary-side switching device located in the lower arm of the secondary-side power circuit. The secondary-side switching device can be a power switching transistor.

[0057] The heat spreader 120 refers to a heat spreader element designed based on the phase change heat transfer principle. The heat spreader 120 is used to receive and homogenize the heat generated by the power conversion unit 110 to avoid local hot spot concentration. Specifically, the heat spreader 120 can be a heat spreader, a high thermal conductivity graphite sheet, an integrated heat spreader substrate, or other hardware devices.

[0058] The heat spreader 120 can be mounted on the heating surface of the power conversion unit 110 in a completely covered and parallel fit. Through close contact, it is ensured that the heat generated by the power conversion unit 110 can be quickly conducted to itself, and then the heat is evenly diffused to the entire plane of the heat spreader 120 by the evaporation-condensation cycle of the internal working fluid.

[0059] It should be noted that the power conversion unit 110 needs to maintain stable operation under conditions such as input voltage fluctuations, output power changes and continuous load disturbances. The primary side upper bridge arm power element, the primary side lower bridge arm power element, the secondary side upper bridge arm power element and the secondary side lower bridge arm power element will exhibit different heating levels as the operating state changes, thereby forming multiple corresponding heat source points on the heat spreader 120.

[0060] In one embodiment, the heat spreader 120 is provided with four heat source points, such as the primary side upper bridge arm heat source point, the primary side lower bridge arm heat source point, the secondary side upper bridge arm heat source point, and the secondary side lower bridge arm heat source point.

[0061] Specifically, the heat source point of the primary side upper bridge arm corresponds to the setting position of the primary side upper bridge arm power element, the heat source point of the primary side lower bridge arm corresponds to the setting position of the primary side lower bridge arm power element, the heat source point of the secondary side upper bridge arm corresponds to the setting position of the secondary side upper bridge arm power element, and the heat source point of the secondary side lower bridge arm corresponds to the setting position of the secondary side lower bridge arm power element.

[0062] The heat source point of the primary side upper arm consists of the conduction loss and switching loss of the primary side upper arm power element; the heat source point of the primary side lower arm consists of the conduction loss and switching loss of the primary side lower arm power element; the heat source point of the secondary side upper arm consists of the conduction loss and switching loss of the secondary side upper arm power element; the heat source point of the secondary side lower arm consists of the conduction loss and switching loss of the secondary side lower arm power element.

[0063] The voltage conversion system 100 can be installed in data center server power supplies, new energy vehicle on-board chargers, industrial motor drive systems, and photovoltaic grid-connected inverters to convert electrical energy of one specification into electrical energy of a target specification, such as converting 220V AC mains power into 300-500V DC power required by the power battery on the vehicle body. During the operation of the voltage conversion system 100, a large amount of heat will be generated due to power loss.

[0064] like Figure 2 As shown, this application provides a thermal equalization control method that can be applied to the aforementioned voltage conversion system. This thermal equalization control method can be applied to the controller included in the voltage conversion system, or to an external controller that is communicatively connected to the voltage conversion system. Figure 2 As shown, the thermal equilibrium control method includes:

[0065] Step 202: Monitor the temperature of multiple heat source points in real time.

[0066] As an example, by setting multiple temperature acquisition devices at multiple heat source points on the heat exchanger plate, the temperature distribution on the heat exchanger plate can be obtained through multi-point temperature acquisition, thereby reflecting the heat distribution status of each power element in the power conversion unit.

[0067] Step 204: Determine whether the heat spreader is experiencing thermal imbalance based on the temperatures of multiple heat source points.

[0068] Thermal equilibrium refers to the fact that different power components in the power conversion unit generate similar power losses and have the same temperature rise trend during operation. This makes the different power components generate similar heat during operation, and the temperature difference collected by each heat source point on the heat spreader is small. At this time, there will be no obvious local high temperature points.

[0069] By judging the magnitude of temperature differences, it is possible to identify whether there are local hot spots caused by excessive power loss or overload of a certain power component, thereby avoiding a decrease in heat transfer efficiency of the heat exchange plate due to uneven temperature.

[0070] Step 206: If thermal imbalance occurs, control the power conversion unit to enter the thermal balance adjustment mode to change the switching loss of the target power element and restore the heat spreader to the thermal balance state; the target power element is the power element corresponding to the location of the heat source point where thermal imbalance occurs.

[0071] The thermal equilibrium adjustment mode is used to perform active control when thermal imbalance occurs in the heat exchanger.

[0072] Switching loss is used to characterize the heat loss generated by power elements in a power conversion unit during the switching process.

[0073] The target power element is used to refer to the power element corresponding to the location of the heat source where thermal imbalance occurs.

[0074] In this embodiment, after determining that thermal imbalance has occurred, the controller can identify the target power element based on the mapping relationship between multiple heat source points on the heat spreader and multiple power elements in the power conversion unit. Subsequently, the controller switches the control strategy of the power conversion unit to put it into thermal balance adjustment mode.

[0075] In thermal equilibrium regulation mode, the controller no longer aims solely at output voltage stability, maximum efficiency, or fixed timing drive. Instead, it adds directional regulation logic for the switching losses of target power components while meeting basic power conversion indicators.

[0076] Thermal equilibrium regulation can be achieved, for example, by adjusting the operating parameters of the target power element, including at least one of the following: switching frequency, duty cycle, and phase shift angle.

[0077] In one possible embodiment, when the temperature of a certain heat source is significantly higher than that of other heat sources, the controller can perform loss reduction adjustment for the target power element corresponding to the location of that heat source.

[0078] Loss reduction regulation may include reducing the effective switching frequency of the relevant branch of the target power element, reducing its high-voltage and high-current overlap range, changing the drive dead time to improve soft switching conditions, adjusting the phase-to-phase power distribution ratio, or transferring part of the load to the parallel power channel located in the low-temperature region.

[0079] If multiple high-temperature heat sources appear simultaneously, the controller can perform multi-objective coordinated adjustment according to the priority order of the heat sources. Without compromising the output stability of the power conversion unit, it can gradually reduce the switching losses of the power components corresponding to each heat source and simultaneously increase the load on the devices in the low-temperature region, so that the temperature difference between multiple heat sources gradually converges.

[0080] The aforementioned thermal balance control method monitors the heat distribution of multiple components in the power conversion unit in real time through multi-point temperature acquisition, actively judges the thermal balance, and dynamically adjusts the control strategy to fundamentally solve the shortcomings of the traditional heat dissipation method in judging thermal balance. This effectively avoids the formation of local hot spots on the surface of the heat exchanger due to uneven loss distribution of power components, and prevents the heat exchanger from experiencing a vicious cycle of local drying and reduced phase change heat transfer efficiency.

[0081] Meanwhile, this thermal balance control method adopts an active, forward-looking thermal management approach, eliminating the need for passive derating or shutdown after detecting actual temperature exceedances. This ensures both the heat dissipation performance of the power conversion unit and its electrical output capability, thereby guaranteeing the reliability, stability, and continuous output capability of the voltage conversion system.

[0082] In some optional embodiments, the thermal equilibrium control method further includes:

[0083] When the heat exchanger returns to thermal equilibrium, the power conversion unit switches to steady-state high-efficiency mode, where the total loss of the power conversion unit is minimized.

[0084] The steady-state high-efficiency mode refers to the stable operating state of the power conversion unit after the heat distribution of the heat exchange plate has been restored to equilibrium, with the goal of efficiency optimization. In this state, the sum of the conduction loss and switching loss of each power element in the power conversion unit is at the lowest level.

[0085] The aforementioned thermal equilibrium control method allows the power conversion unit to promptly enter a low-loss operating state after the heat exchanger achieves thermal equilibrium, avoiding the introduction of additional switching losses by remaining in the thermal regulation state. This also improves the electrical output efficiency of the power conversion unit and enhances operational stability. Since total losses are minimized, the voltage conversion system reduces energy waste while maintaining thermal equilibrium.

[0086] In some optional embodiments, the power conversion unit includes a primary-side power circuit and a secondary-side power circuit;

[0087] Before step 202, the following are also included:

[0088] Multiple controllable freewheeling modes of the primary-side power circuit and multiple controllable freewheeling modes of the secondary-side power circuit are preset.

[0089] A total loss model for the power conversion unit is established, including the conduction and switching losses of each power element in the primary power circuit and the conduction and switching losses of each power element in the secondary power circuit. The total loss is then decomposed and mapped to the heat source points in different locations on the heat spreader plate.

[0090] For different electrical operating conditions of the power conversion unit, a multi-objective control strategy is established with different loss distributions as the optimization objective. The multi-objective control strategy includes the correspondence between control parameters and controllable freewheeling modes under different electrical operating conditions. The control parameters include switching frequency, primary duty cycle, secondary duty cycle and phase shift angle.

[0091] Different controllable freewheeling modes are used to limit different current flow paths during the commutation process, thereby changing the conduction and switching losses borne by different power components.

[0092] The total loss model is used to uniformly characterize the loss composition of the primary and secondary power circuits, and the calculated loss is mapped to the heat source point on the heat spreader according to the installation position of each power element, so as to establish the correspondence between electrical loss and heat distribution.

[0093] Multi-objective control strategies are used to coordinate loss distribution under different input voltage, output power and load disturbance conditions, so as to coordinate the selection of control parameters and controllable freewheeling mode, thereby achieving temperature balance at the heat source point.

[0094] In this embodiment, by first establishing the mapping relationship between the conduction loss, switching loss, and heat source point of each power element in the power conversion unit, and then selecting corresponding control parameters and controllable freewheeling mode according to different electrical operating conditions, the heat is more easily redistributed to the target area, and the probability of local hot spots is reduced. Since the controlled object directly acts on the loss distribution of the primary and secondary sides, the heat source intensity can be adjusted before the temperature anomaly expands, maintaining the heat distribution of the heat spreader.

[0095] like Figure 3 As shown in the figure, as an example, the conduction losses of the primary upper bridge arm power elements S1 and S2 and the primary lower bridge arm power elements S3 and S4 in the primary power circuit can be expressed as Pcon_Sx (x=1,2,3,4) and the switching losses can be expressed as Psw_Sx (x=1,2,3,4). The conduction losses of the secondary upper bridge arm power elements Q1 and Q2 and the secondary lower bridge arm power elements Q3 and Q4 in the secondary power circuit can be expressed as Pcon_Qx (x=1,2,3,4) and the switching losses can be expressed as Psw_Qx (x=1,2,3,4).

[0096] Among them, the heat source point of the primary side upper bridge arm on the heat spreader is mainly affected by the conduction loss Pcon_S1, Pcon_S2 and the switching loss Psw_S1, Psw_S2 of the primary side upper bridge arm power elements S1 and S2.

[0097] The heat source point of the primary side lower bridge arm on the heat spreader is mainly affected by the conduction loss Pcon_S3, Pcon_S4 and the switching loss Psw_S3, Psw_S4 of the primary side lower bridge arm power elements S3 and S4.

[0098] The heat source points of the secondary side upper bridge arm on the heat spreader are mainly affected by the conduction losses Pcon_Q1, Pcon_Q2 and the switching losses Psw_Q1, Psw_Q2 of the power components Q1 and Q2 on the secondary side upper bridge arm.

[0099] The heat source point of the secondary lower bridge arm on the heat spreader is mainly affected by the conduction loss Pcon_Q3, Pcon_Q4 and the switching loss Psw_Q3, Psw_Q4 of the power components Q3 and Q4 in the secondary lower bridge arm.

[0100] During the operation of the power conversion unit, in the commutation process of any controllable freewheeling mode, the switching loss of any one of the power elements S1, S2, S3, S4, Q1, Q2, Q3, and Q4 within one switching cycle is shown in the following formula:

[0101]

[0102] Where td represents the dead-time end time of the current power element; von(td) represents the turn-on voltage of the current power element; tr represents the rise time of the turn-on current of the current power element; and Eons represents the inherent energy loss of the junction capacitance discharge of the current power element when the turn-on voltage is 400V.

[0103] During the operation of the power conversion unit, the conduction loss of any one of the power elements S1, S2, S3, S4, Q1, Q2, Q3, and Q4 in one switching cycle is shown in the following formula:

[0104]

[0105] Where Ron represents the on-resistance of the current power element; iL(tx) represents the magnitude of the inductor current of the current power element at time tx; Indicates the current switching frequency of the power element; This represents the magnitude of the inductor voltage of the power element at time tx; L is... Figure 3 The inductance of the inductor L; This represents the effective value of the inductor current during the current switching cycle.

[0106] Therefore, the total loss model can be based on the above. and form.

[0107] Furthermore, as an example, such as Figure 3 As shown, taking this circuit structure as an example, a multi-objective control strategy can be established based on the following inductor current optimal control strategy and the zero-voltage switching optimization strategy of power elements in the primary-side power circuit.

[0108] Specifically, the optimal control strategy for inductor current indicates that when the external phase shift angle φ of the power element in the secondary power circuit and the duty cycle Ds satisfy the following relationship, the optimal control of the inductor current can be achieved, minimizing the loss of the power element in the secondary power circuit.

[0109]

[0110] Where K represents Figure 3 The turns ratio of transformer T in the circuit.

[0111] The zero-voltage switching optimization strategy for power components in the primary power circuit indicates that when the outward phase angle φ of the power components in the secondary power circuit satisfies the following relationship, zero-voltage switching of the power components in the primary power circuit can be achieved, thereby reducing the losses of the power components in the primary power circuit. However, due to the increase in return current, the effective value of the inductor current increases, and the losses of the power components in the secondary power circuit will increase relatively.

[0112]

[0113] As an example, such as Figure 4 As shown, the power conversion unit is a DAB converter as an example. Under heavy load conditions, the DAB converter has K*Vsec>Vpri, where K is the transformer turns ratio.

[0114] At this point, the power elements of the secondary power circuit can achieve zero-voltage switching. The main loss of the power elements in the secondary power circuit is the conduction loss, which is mainly determined by the effective value of the inductor current of the secondary power circuit. For the power elements of the primary power circuit to achieve zero-voltage switching, the external phase angle φ and duty cycle Ds of the power elements in the secondary power circuit need to meet certain constraints. The main loss of the power elements in the primary power circuit is the sum of the conduction loss and the switching loss.

[0115] In summary, based on the optimal control strategy for inductor current and the zero-voltage switching optimization strategy for power components in the primary power circuit, the relationship between the external phase shift angle φ and duty cycle Ds of the power components in the secondary power circuit and the losses of the power components in the primary and secondary power circuits can be established. This allows for the adjustment of at least some of the following parameters: the switching frequency, primary duty cycle, secondary duty cycle, and phase shift angle of the power components in the primary power circuit.

[0116] In this embodiment, the controller can further establish a multi-objective control strategy based on the relationship between the external phase shift angle φ and duty cycle Ds of the power element in the secondary power circuit, as indicated by the optimal control strategy for inductor current and the zero-voltage switching optimization strategy of the power element in the primary power circuit, and the losses of the power element in the primary and secondary power circuits. This strategy aims to optimize different loss distributions and control the switching frequency, primary duty cycle, secondary duty cycle, and phase shift angle. This allows for the adjustment of multiple controllable freewheeling modes of the primary and secondary power circuits by adjusting at least a portion of the switching frequency, primary duty cycle, secondary duty cycle, and phase shift angle of the power element in the primary and secondary power circuits.

[0117] The aforementioned thermal balance control method allows the heat source distribution of the power conversion unit to be actively adjusted by control parameters, and local thermal imbalances on the heat exchange plate can be quickly suppressed, enabling the voltage conversion system to maintain stable operation at high efficiency and improving the long-term reliability of the voltage conversion system.

[0118] In some optional embodiments, the step of decomposing and mapping the total loss to heat source points corresponding to different locations on the vapor chamber includes:

[0119] The total loss is decomposed and mapped to the corresponding primary side upper arm heat source point, primary side lower arm heat source point, secondary side upper arm heat source point, and secondary side lower arm heat source point on the heat spreader plate.

[0120] Specifically, the heat source point loss of the primary side upper arm consists of the conduction loss and switching loss of the primary side upper arm power element; the heat source point loss of the primary side lower arm consists of the conduction loss and switching loss of the primary side lower arm power element; the heat source point loss of the secondary side upper arm consists of the conduction loss and switching loss of the secondary side upper arm power element; and the heat source point loss of the secondary side lower arm consists of the conduction loss and switching loss of the secondary side lower arm power element.

[0121] The steps for real-time monitoring of the temperature of multiple heat sources include:

[0122] Real-time monitoring of the temperatures of the primary side upper arm heat source point, the primary side lower arm heat source point, the secondary side upper arm heat source point, and the secondary side lower arm heat source point.

[0123] Among them, the primary side upper bridge arm heat source point is used to correspond to the heat source position of the primary side upper bridge arm power element, the primary side lower bridge arm heat source point is used to correspond to the heat source position of the primary side lower bridge arm power unit, the secondary side upper bridge arm heat source point is used to correspond to the heat source position of the secondary side upper bridge arm power element, and the secondary side lower bridge arm heat source point is used to correspond to the heat source position of the secondary side lower bridge arm power element.

[0124] As an example, the total loss is calculated by the controller based on the current, voltage, switching frequency and duty cycle, and distributed to each heat source point according to the position of the primary side upper arm power element, the primary side lower arm power element, the secondary side upper arm power element and the secondary side lower arm power element.

[0125] During the operation of the voltage conversion system, the controller first decomposes the total loss into the heat source points corresponding to the primary side upper arm power components, primary side lower arm power components, secondary side upper arm power components, and secondary side lower arm power components. Then, it synchronously reads the temperature of each heat source point, thereby correlating the changes in electrical loss with the local thermal state. The controller further determines whether there is thermal imbalance in each region based on the temperature distribution, and provides a basis for subsequent adjustment of the power conversion state.

[0126] The aforementioned thermal equilibrium control method can refine the total loss to the heat source point at the bridge arm level, so that the temperature monitoring object corresponds to the actual heat source, thereby improving the accuracy of heat distribution identification and enhancing the ability to perceive local thermal imbalance, which in turn helps to maintain the heat transfer uniformity of the heat exchange plate and the operational stability of the voltage conversion system.

[0127] In some optional embodiments, the various controllable freewheeling modes of the primary-side power circuit and the secondary-side power circuit include the alternating freewheeling mode of the upper and lower transistors, the freewheeling mode of the upper transistor only, and the freewheeling mode of the lower transistor only.

[0128] The alternating freewheeling current sharing mode refers to the primary upper bridge arm power element and the primary lower bridge arm power element in the primary power circuit, or the secondary upper bridge arm power element and the secondary lower bridge arm power element in the secondary power circuit, taking turns to bear the freewheeling current according to a preset timing sequence, so that the conduction loss and related switching loss during the freewheeling period are evenly distributed between the upper and lower transistors of the primary and secondary power circuits.

[0129] The freewheeling mode with only the upper transistor refers to the freewheeling current being mainly carried by the primary upper bridge arm power element in the primary power circuit and the secondary upper bridge arm power element in the secondary power circuit, in order to change the loss distribution between the upper and lower transistors in the primary and secondary power circuits.

[0130] The freewheeling mode with only the lower transistor refers to the freewheeling current being mainly carried by the primary lower bridge arm power element in the primary power circuit and the secondary lower bridge arm power element in the secondary power circuit, so as to achieve the opposite loss distribution method as the freewheeling mode with only the upper transistor.

[0131] All three modes mentioned above are controllable freewheeling modes, and are applicable to primary-side power circuits and secondary-side power circuits respectively, so as to adjust the heating location and heat source intensity under different electrical conditions.

[0132] As an example, such as Figure 3 The diagram shows a specific circuit structure of a power conversion unit. In this power conversion unit, the MS0-alternating freewheeling current sharing mode refers to the primary-side upper bridge arm power elements S1 and S2 and the primary-side lower bridge arm power elements S3 and S4 in the primary-side power circuit taking turns to bear the freewheeling current according to a preset timing sequence, or the secondary-side upper bridge arm power elements Q1 and Q2 and the secondary-side lower bridge arm power elements Q3 and Q4 in the secondary-side power circuit taking turns to bear the freewheeling current according to a preset timing sequence.

[0133] MS1 - Freewheeling mode only refers to the freewheeling current being mainly carried by the primary upper bridge arm power elements S1 and S2 in the primary power circuit and the secondary upper bridge arm power elements Q1 and Q2 in the secondary power circuit.

[0134] MS2 - Lower-side freewheeling mode refers to the freewheeling current being primarily carried by the primary-side lower-side power elements S3 and S4 in the primary-side power circuit and the secondary-side lower-side power elements Q3 and Q4 in the secondary-side power circuit.

[0135] As an example, such as Figure 5 The figure shows the operating waveforms of the secondary upper bridge arm power elements Q1 and Q2 and the secondary lower bridge arm power elements Q3 and Q4 in the secondary power circuit under three controllable freewheeling modes: MS1 - upper duct freewheeling mode only, MS2 - lower duct freewheeling mode only, and MS0 - alternating freewheeling mode of upper and lower ducts.

[0136] The aforementioned thermal balance control method, by setting three controllable freewheeling modes, can flexibly adjust the loss distribution of the primary and secondary power circuits without changing the main power transmission path, thereby suppressing temperature differences at heat source points and reducing localized heat accumulation on the heat spreader. Since the controllable freewheeling modes can be switched according to different operating conditions, a controllable trade-off between thermal balance regulation and efficient operation can be established, thus improving temperature distribution consistency, heat dissipation utilization, and the long-term operational stability of the voltage conversion system.

[0137] In some alternative embodiments, step 206 includes:

[0138] Calculate the average temperature of multiple heat source points;

[0139] Calculate the difference between the temperature of multiple heat sources and their average value;

[0140] If the difference is greater than the preset threshold, the heat spreader will experience thermal imbalance at the heat source point.

[0141] In this embodiment, the average value is used to characterize the overall level of the current temperature of multiple heat source points, serving as a statistical benchmark for judging the degree of local temperature deviation.

[0142] The difference is used to characterize the deviation of the temperature of a single heat source point from the average temperature. The larger the deviation, the more significant the difference in heat distribution between that heat source point and the other heat source points.

[0143] When the difference exceeds the preset threshold, the controller can assume that the temperature distribution plate in the area corresponding to the heat source point has thermal imbalance.

[0144] As an example, the controller can first sum the temperatures of each heat source point and divide by the number of heat source points to obtain an average value, and then subtract the average value from the temperature of each heat source point to obtain the temperature difference value for each heat source point.

[0145] If the difference at a certain heat source point is greater than a preset threshold, the controller outputs a judgment result that thermal imbalance has occurred at that heat source point, and triggers subsequent thermal balance adjustment accordingly.

[0146] This temperature difference judgment method can directly reflect the degree of abnormality of local heat sources relative to the overall heat distribution, and is applicable to the collaborative judgment of multiple location areas such as the primary side upper arm heat source point, the primary side lower arm heat source point, the secondary side upper arm heat source point, and the secondary side lower arm heat source point.

[0147] The aforementioned thermal balance control method collects the temperatures of multiple heat source points and calculates the average value, so that the identification of thermal imbalance does not rely on a single absolute temperature, but is based on the relative temperature difference between multiple heat source points, thereby enabling more accurate identification of local hot spots or local low-heat areas.

[0148] Since the judgment result can directly locate the specific heat source, it can provide a basis for subsequent adjustment of the switching loss of the corresponding power components, thereby improving the heat distribution uniformity on the heat exchange plate, reducing the risk of local overheating, and helping to maintain the stable operation and continuous efficient heat transfer of the voltage conversion system.

[0149] In some alternative embodiments, step 206 includes:

[0150] Calculate the temperature rise gradient at each heat source point;

[0151] Determine whether thermal imbalance occurs at the corresponding heat source point based on the temperature rise gradient;

[0152] If the temperature rise gradient is greater than the preset gradient threshold, thermal imbalance will occur at the corresponding heat source point.

[0153] Among them, the temperature rise gradient is used to characterize the rate of temperature change of a heat source point over time, reflecting how fast a heat source point heats up between adjacent sampling times.

[0154] The preset gradient threshold is used to limit the upper limit of the allowable temperature rise rate of the heat source point. The preset gradient threshold can be set in combination with the thermal response capability of the heat exchange plate, the rated operating conditions of the power conversion unit, and the allowable temperature rise range to ensure timely identification of local abnormal temperature rise.

[0155] As an example, the controller can acquire the temperature sequence of each heat source point according to a preset sampling period, and calculate the temperature rise gradient based on the temperature of two adjacent samples and the time interval between the two adjacent samples, which can be expressed as the ratio of the temperature change to the sampling time difference.

[0156] When the temperature gradient at a heat source point continues to increase and exceeds a preset gradient threshold, it can be determined that there is thermal imbalance in the area corresponding to that heat source point.

[0157] In one embodiment, to improve the reliability of the judgment, the temperature rise gradient can also be smoothed by combining multiple consecutive sampling results to reduce the impact of instantaneous noise on the judgment result.

[0158] It should be noted that the controller simultaneously monitors multiple heat sources and calculates their respective temperature rise gradients. This gradient is then compared to a preset gradient threshold to identify heat sources with abnormal temperature rise. Furthermore, for heat sources identified as having thermal imbalances, the controller can further adjust their corresponding regions, providing a basis for subsequently controlling the switching losses of target power components and restoring the heat source distribution to a balanced state.

[0159] The aforementioned thermal balance control method no longer relies on the absolute value of temperature to determine the thermal imbalance of the heat spreader, but instead identifies the rate of temperature rise. This allows for earlier detection of localized heat concentration trends, reducing the risk of expanding thermal imbalance and improving the timeliness and accuracy of thermal balance regulation. Furthermore, by identifying abnormal heat sources in advance, it can reduce the decrease in heat transfer efficiency caused by localized overheating of the heat spreader, thereby improving the stability, efficiency, and long-term reliability of the voltage conversion system.

[0160] In some alternative embodiments, step 206 includes:

[0161] Based on the location of the heat source and the direction of the temperature difference corresponding to the thermal imbalance, the controllable freewheeling mode and control parameters that enable the power element corresponding to the heat source to bear less or more losses under the current electrical conditions are selected in the multi-objective control strategy. The control strategy of the power conversion unit is adjusted according to the selected controllable freewheeling mode and control parameters.

[0162] If the direction of the temperature difference indicates that the temperature of the heat source is too high, a control strategy that causes the power element corresponding to the heat source to bear less loss is selected; otherwise, a control strategy that causes the power element corresponding to the heat source to bear more loss is selected.

[0163] Among them, the temperature difference direction is used to characterize the temperature relationship between the heat source point and other heat source points, and to indicate whether the corresponding power element should reduce or increase the loss distribution in the thermal balance adjustment mode.

[0164] Multi-objective control strategies are used to comprehensively consider the effects of output power, switching frequency, duty cycle and phase shift angle on efficiency and heat distribution under the current electrical operating conditions, so as to select the operating mode that meets the thermal correction objective.

[0165] Controllable freewheeling mode is used to define the freewheeling path of current in power devices. Different controllable freewheeling modes will cause the conduction loss and switching loss to be redistributed among different devices, thereby changing the temperature rise trend of the corresponding heat source point.

[0166] As an example, after acquiring the temperature of each heat source, the controller first determines whether the target heat source is in a state of being too high or too low based on the direction of the temperature difference. Then, in combination with the current voltage, current and load conditions, it selects a controllable freewheeling mode that matches the preset control parameter combination and simultaneously corrects the switching frequency, duty cycle or phase shift angle to adjust the switching loss of the target power element to either decrease or increase.

[0167] Specifically, if the target heat source temperature is too high, the controller will prioritize selecting a current path that allows the power element at that location to bear less loss in order to reduce local heat generation; if the target heat source temperature is too low, the controller will select a path that allows the power element at that location to bear more loss in order to increase local heat input.

[0168] This control method directly applies thermal balance adjustment to the power components corresponding to the heat source, thereby correcting the local loss bias caused by thermal imbalance and prompting the heat to be redistributed across the heat spreader and gradually return to equilibrium. Since the adjustment targets switching losses and controllable freewheeling modes, it can achieve active adjustment on the heat source side without significantly altering the external heat dissipation conditions of the system.

[0169] The aforementioned thermal equilibrium control method can directionally adjust the loss distribution according to the location of the heat source and the direction of the temperature difference, reduce the risk of further temperature rise in the high-temperature area, improve the heat utilization in the low-temperature area, enable the heat exchange plate to recover to the thermal equilibrium state more quickly, and help maintain the power conversion unit to operate under conditions of high efficiency and high reliability.

[0170] It should be understood that although the steps in the flowcharts of the above embodiments are shown sequentially as indicated by the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise expressly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders.

[0171] Moreover, at least some steps in the flowcharts involved in the above embodiments may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be executed in turn or alternately with other steps or at least some of the steps or stages in other steps.

[0172] Based on the same inventive concept, this application also provides a thermal balance control device for implementing the thermal balance control method described above. The solution provided by this thermal balance control device is similar to the solution described in the thermal balance control method above. Therefore, the specific limitations in one or more device embodiments provided below can be found in the limitations of the thermal balance control method described above, and will not be repeated here.

[0173] In one embodiment, such as Figure 6 As shown, a thermal equalization control device 600 is provided and applied to a voltage conversion system. The voltage conversion system includes a power conversion unit and a heat spreader. The power conversion unit includes multiple power elements, which are distributed in different positions on the heat spreader and are all thermally connected to the heat spreader. The heat spreader includes multiple heat source points distributed in different positions.

[0174] The thermal balance control device 600 includes:

[0175] Detection module 602 is used to monitor the temperature of multiple heat source points in real time;

[0176] The judgment module 604 is used to determine whether the heat spreader has thermal imbalance based on the temperature of multiple heat source points.

[0177] The control module 606 is used to control the power conversion unit to enter the thermal balance adjustment mode if thermal imbalance occurs, so as to change the switching loss of the target power element and restore the heat spreader to the thermal balance state; the target power element is the power element corresponding to the location of the heat source point where thermal imbalance occurs.

[0178] In some alternative embodiments,

[0179] Control module 606 is also configured as follows:

[0180] When the heat exchanger returns to thermal equilibrium, the power conversion unit switches to steady-state high-efficiency mode, where the total loss of the power conversion unit is minimized.

[0181] like Figure 7 As shown, in some optional embodiments, the power conversion unit includes a primary-side power circuit and a secondary-side power circuit;

[0182] The thermal equalization control device 600 also includes a setup module 601, which is configured to:

[0183] Multiple controllable freewheeling modes of the primary-side power circuit and multiple controllable freewheeling modes of the secondary-side circuit are preset;

[0184] A total loss model for the power conversion unit is established, including the conduction and switching losses of each power element in the primary power circuit and the conduction and switching losses of each power element in the secondary power circuit. The total loss is then decomposed and mapped to the heat source points in different locations on the heat spreader plate.

[0185] For different electrical operating conditions of the power conversion unit, a multi-objective control strategy is established with different loss distributions as the optimization objective. The multi-objective control strategy includes the correspondence between control parameters under different electrical operating conditions and multiple controllable freewheeling modes. The control parameters include switching frequency, primary duty cycle, secondary duty cycle and phase shift angle.

[0186] In some optional embodiments, the establishment module 601 is further configured to:

[0187] The total loss is decomposed and mapped to the corresponding primary side upper bridge arm heat source point, primary side lower bridge arm heat source point, secondary side upper bridge arm heat source point, and secondary side lower bridge arm heat source point on the heat spreader plate.

[0188] Specifically, the heat source point loss of the primary side upper arm consists of the conduction loss and switching loss of the primary side upper arm power element; the heat source point loss of the primary side lower arm consists of the conduction loss and switching loss of the primary side lower arm power element; the heat source point loss of the secondary side upper arm consists of the conduction loss and switching loss of the secondary side upper arm power element; and the heat source point loss of the secondary side lower arm consists of the conduction loss and switching loss of the secondary side lower arm power element.

[0189] The detection module 602 is also configured as follows:

[0190] Real-time monitoring of the temperatures of the primary side upper arm heat source point, the primary side lower arm heat source point, the secondary side upper arm heat source point, and the secondary side lower arm heat source point.

[0191] In some optional embodiments, the various controllable freewheeling modes of the primary-side power circuit and the secondary-side power circuit include the alternating freewheeling mode of the upper and lower transistors, the freewheeling mode of the upper transistor only, and the freewheeling mode of the lower transistor only.

[0192] In some optional embodiments, the determination module 604 is further configured to:

[0193] Calculate the average temperature of multiple heat source points;

[0194] Calculate the difference between the temperature of multiple heat sources and their average value;

[0195] If the difference is greater than the preset threshold, the heat spreader will experience thermal imbalance at the heat source point.

[0196] In some optional embodiments, the determination module 604 is further configured to:

[0197] Calculate the temperature rise gradient at each heat source point;

[0198] Determine whether thermal imbalance occurs at the corresponding heat source point based on the temperature rise gradient;

[0199] If the temperature rise gradient is greater than the preset gradient threshold, thermal imbalance will occur at the corresponding heat source point.

[0200] In some alternative embodiments, the control module 606 is further configured to:

[0201] Based on the location of the heat source and the direction of the temperature difference corresponding to the thermal imbalance, a controllable freewheeling mode and control parameters that reduce or eliminate losses in the power element corresponding to the heat source under the current electrical conditions are selected from the pre-established multi-objective control strategy. The control strategy of the power conversion unit is then adjusted according to the selected controllable freewheeling mode and control parameters. Specifically, if the direction of the temperature difference indicates that the temperature of the heat source is too high, a control strategy that reduces losses in the power element corresponding to the heat source is selected; otherwise, a control strategy that increases losses in the power element corresponding to the heat source is selected.

[0202] Each module in the above-mentioned device can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in the processor of a computer device in hardware form or independent of it, or stored in the memory of a computer device in software form, so that the processor can call and execute the operations corresponding to each module.

[0203] Figure 8 A schematic diagram of the structure of the electronic device provided in this application. Figure 8 As shown, the electronic device 800 provided in this embodiment includes at least one processor 801 and a memory 802. Optionally, the device 800 also includes a communication component 803.

[0204] The processor 801, memory 802, and communication component 803 are connected via bus 804.

[0205] In a specific implementation, at least one processor 801 executes computer execution instructions stored in memory 802, causing at least one processor 801 to perform the above-described method.

[0206] The specific implementation process of processor 801 can be found in the above method embodiments, and its implementation principle and technical effect are similar. It will not be repeated here.

[0207] In the above embodiments, it should be understood that the processor can be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), etc.

[0208] The general-purpose processor can be a microprocessor or any conventional processor. The steps of the method disclosed in the invention can be directly manifested as being executed by a hardware processor, or being executed by a combination of hardware and software modules in the processor.

[0209] The memory may include random access memory (RAM) and may also include non-volatile memory (NVM), such as at least one disk storage device.

[0210] The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc.

[0211] Buses can be categorized into address buses, data buses, control buses, etc. For ease of illustration, the buses shown in the accompanying drawings are not limited to a single bus or a single type of bus.

[0212] This application also provides a computer program product, including a computer program that, when executed by a processor, implements the above-described method.

[0213] This application also provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, implement the above-described method.

[0214] The aforementioned readable storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk. The readable storage medium can be any available medium accessible to a general-purpose or special-purpose computer.

[0215] An exemplary readable storage medium is coupled to a processor, enabling the processor to read information from and write information to the readable storage medium. Of course, the readable storage medium can also be a component of the processor. The processor and the readable storage medium can reside in an Application Specific Integrated Circuit (ASIC). Alternatively, the processor and the readable storage medium can exist as discrete components in the device.

[0216] The division of units is merely a logical functional division; in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be indirect coupling or communication connection through some interfaces, devices, or units, and may be electrical, mechanical, or other forms.

[0217] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0218] In addition, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0219] If a function is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0220] Those skilled in the art will understand that all or part of the steps of the above-described method embodiments can be implemented by hardware related to program instructions. The aforementioned program can be stored in a computer-readable storage medium. When executed, the program performs the steps of the above-described method embodiments; and the aforementioned storage medium includes various media capable of storing program code, such as ROM, RAM, magnetic disks, or optical disks.

[0221] Finally, it should be noted that other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This invention is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein, and is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

Claims

1. A thermal equilibrium control method, characterized in that, The device is applied to a voltage conversion system, which includes a power conversion unit and a heat spreader. The power conversion unit includes multiple power components distributed in different areas on the heat spreader and all of them are thermally connected to the heat spreader. The heat spreader includes multiple heat source points distributed in different areas. The thermal equilibrium control method includes: Real-time monitoring of the temperature of multiple heat source points; Based on the temperatures of the multiple heat source points, determine whether the heat spreader exhibits thermal imbalance. If thermal imbalance occurs, the power conversion unit is controlled to enter the thermal balance adjustment mode to change the switching loss of the target power element and restore the heat spreader to the thermal balance state; the target power element is the power element corresponding to the location of the heat source point where thermal imbalance occurs.

2. The thermal equilibrium control method according to claim 1, characterized in that, The method further includes: When the heat exchanger returns to thermal equilibrium, the power conversion unit is controlled to switch to steady-state high-efficiency mode, where the total loss of the power conversion unit is minimized.

3. The thermal equilibrium control method according to claim 1, characterized in that, The power conversion unit includes a primary-side power circuit and a secondary-side power circuit; Before the real-time monitoring of the temperature of the multiple heat source points, the method further includes: The primary-side power circuit and the secondary-side circuit are pre-defined to have multiple controllable freewheeling modes. A total loss model of the power conversion unit is established, including the conduction loss and switching loss of each power element in the primary power circuit and the conduction loss and switching loss of each power element in the secondary power circuit. The total loss is then decomposed and mapped to the heat source points in different locations on the heat spreader plate. For different electrical operating conditions of the power conversion unit, a multi-objective control strategy is established with different loss distributions as the optimization objective. The multi-objective control strategy includes the correspondence between control parameters under different electrical operating conditions and various controllable freewheeling modes. The control parameters include switching frequency, primary duty cycle, secondary duty cycle and phase shift angle.

4. The thermal equilibrium control method according to claim 3, characterized in that, The step of decomposing and mapping the total loss to heat source points in different locations on the temperature distribution plate includes: The total loss is decomposed and mapped to the corresponding primary side upper bridge arm heat source point, primary side lower bridge arm heat source point, secondary side upper bridge arm heat source point, and secondary side lower bridge arm heat source point on the heat spreader plate. The losses of the primary side upper bridge arm heat source points consist of the conduction losses and switching losses of the primary side upper bridge arm power elements; the losses of the primary side lower bridge arm heat source points consist of the conduction losses and switching losses of the primary side lower bridge arm power elements; the losses of the secondary side upper bridge arm heat source points consist of the conduction losses and switching losses of the secondary side upper bridge arm power elements; and the losses of the secondary side lower bridge arm heat source points consist of the conduction losses and switching losses of the secondary side lower bridge arm power elements. The real-time monitoring of the temperature of multiple heat source points includes: The temperatures of the primary side upper arm heat source point, the primary side lower arm heat source point, the secondary side upper arm heat source point, and the secondary side lower arm heat source point are monitored in real time.

5. The thermal equilibrium control method according to claim 3, characterized in that, The various controllable freewheeling modes of the primary-side power circuit and the secondary-side power circuit include the alternating freewheeling mode of the upper and lower transistors, the freewheeling mode of the upper transistor only, and the freewheeling mode of the lower transistor only.

6. The thermal equilibrium control method according to claim 1, characterized in that, The step of determining whether the heat spreader exhibits thermal imbalance based on the temperatures of the multiple heat source points includes: Calculate the average temperature of the multiple heat source points; Calculate the difference between the temperature of the plurality of heat sources and the average value; If the difference is greater than a preset threshold, then the heat spreader will experience thermal imbalance at the heat source point.

7. The thermal equilibrium control method as described in claim 1, characterized in that, The step of determining whether the heat spreader exhibits thermal imbalance based on the temperatures of the multiple heat source points includes: Calculate the temperature rise gradient at each of the aforementioned heat source points; Based on the temperature rise gradient, determine whether the corresponding heat source point experiences thermal imbalance; If the temperature rise gradient is greater than a preset gradient threshold, then thermal imbalance occurs at the corresponding heat source point.

8. The thermal equilibrium control method according to any one of claims 3 to 7, characterized in that, The method of controlling the power conversion unit to enter the thermal equilibrium adjustment mode to change the switching losses of the target power element and restore the heat spreader to a thermal equilibrium state includes: Based on the location of the heat source and the direction of the temperature difference corresponding to the thermal imbalance, a controllable freewheeling mode and control parameters that cause the power element corresponding to the heat source to bear less or more losses under the current electrical operating conditions are selected from the pre-established multi-objective control strategy. The control strategy of the power conversion unit is adjusted according to the selected controllable freewheeling mode and control parameters. Specifically, if the direction of the temperature difference indicates that the temperature of the heat source is too high, a control strategy that causes the power element corresponding to the heat source to bear less losses is selected; otherwise, a control strategy that causes the power element corresponding to the heat source to bear more losses is selected.

9. A thermal equalization control device, characterized in that, The device is applied to a voltage conversion system, which includes a power conversion unit and a heat spreader. The power conversion unit includes multiple power components distributed in different areas on the heat spreader and all of them are thermally connected to the heat spreader. The heat spreader includes multiple heat source points distributed in different areas. The thermal equilibrium control device includes: The detection module is used to monitor the temperature of multiple heat source points in real time; The judgment module is used to determine whether the heat spreader has thermal imbalance based on the temperature of the multiple heat source points. The control module is used to control the power conversion unit to enter the thermal balance adjustment mode if thermal imbalance occurs, so as to change the switching loss of the target power element and restore the heat spreader to the thermal balance state; the target power element is the power element corresponding to the location of the heat source point where thermal imbalance occurs.

10. A voltage conversion system, characterized in that, The voltage conversion system includes a power conversion unit and a heat spreader; the power conversion unit includes multiple power elements distributed in different locations on the heat spreader and all of them are thermally connected to the heat spreader; the heat spreader includes multiple heat source points distributed in different locations; the voltage conversion system is used to employ the method as described in any one of claims 1 to 8.

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