Power conversion device, heat dissipation unit health state determination method thereof and energy system

Abstract

The embodiment of the invention provides a power conversion device, a method for determining the health state of a heat dissipation unit of the power conversion device and an energy system. The power conversion device comprises a power module, a heat dissipation unit and a controller, the controller is used for controlling to change the power of the power module and change the fan rotating speed of the fan in the heat dissipation unit when the power conversion device is in the first working state under the condition that the module temperature of the power module is kept unchanged, so that the power conversion device is changed to a second working state; and determining the health state of the heat dissipation unit according to the power of the power module and the fan rotating speed of the fan in the heat dissipation unit in the first working state and the power of the power module and the fan rotating speed of the fan in the heat dissipation unit in the second working state. The module temperature of the power module is kept unchanged, and the health state of the heat dissipation unit can be accurately determined according to the power of the power module in the first working state and the second working state and the fan rotating speed of the fan in the heat dissipation unit.

Description

Technical Field

[0001] The embodiments in this specification relate to the field of power electronics technology, specifically to a power conversion device and a method for determining the health status of its heat dissipation unit, as well as an energy system. Background Technology

[0002] During operation, the power modules of a power converter generate significant heat. Overheating of the power modules increases the risk of performance degradation or damage to internal components. Therefore, heat dissipation units are installed within the power converter to cool the power modules.

[0003] However, the accuracy of existing methods for assessing the health status of heat dissipation units is not high. Summary of the Invention

[0004] This specification provides a power conversion device and a method for determining the health status of its heat dissipation unit, as well as an energy system, through several embodiments, which can improve the accuracy of determining the health status of the heat dissipation unit of the power conversion device to a certain extent.

[0005] This specification provides a power conversion device, including: a power module, a heat dissipation unit, and a controller; the heat dissipation unit is used to dissipate heat from the power module; the controller is used to, when the power conversion device is in a first operating state, control and change the power of the power module and the fan speed of the fan in the heat dissipation unit while maintaining the module temperature of the power module constant, so that the power conversion device is in a second operating state; the health status of the heat dissipation unit is determined based on the power of the power module and the fan speed of the fan in the heat dissipation unit in the first operating state, and the power of the power module and the fan speed of the fan in the heat dissipation unit in the second operating state.

[0006] In some embodiments, controlling the power of the power module and the fan speed of the fan in the heat dissipation unit to put the power conversion device into a second operating state includes: when the controller controls the power of the power module to change to a specified target power, controlling the fan speed of the fan in the heat dissipation unit to maintain the temperature of the power module at the module temperature.

[0007] In some embodiments, the specified target power is less than the power of the power module in the first operating state; controlling the fan speed of the fan in the heat dissipation unit to maintain the temperature of the power module at the module temperature includes: reducing the fan speed of the heat dissipation unit.

[0008] In some embodiments, the specified target power is greater than the power of the power module in the first operating state, and controlling the fan speed of the fan in the heat dissipation unit to maintain the temperature of the power module at the module temperature includes: increasing the fan speed of the heat dissipation unit.

[0009] In some embodiments, when the power of the power module is changed to the specified target power, the fan of the heat dissipation unit corresponds to a predicted speed change. The health status of the heat dissipation unit is determined based on the power of the power module and the fan speed of the heat dissipation unit in the first operating state, and the power of the power module and the fan speed of the heat dissipation unit in the second operating state. This includes: determining the speed change between the fan speed of the heat dissipation unit in the first operating state and the fan speed in the second operating state; if the absolute value of the difference between the speed change and the predicted speed change is less than a first specified threshold, the heat dissipation unit is considered to be in a normal state; or, if the absolute value of the difference between the speed change and the predicted speed change is greater than the first specified threshold, the heat dissipation unit is considered to be in an abnormal state.

[0010] In some embodiments, controlling the power of the power module and the fan speed of the heat dissipation unit to put the power conversion device into a second operating state includes: when the controller controls the fan speed of the heat dissipation unit to change to a specified target speed, controlling the power of the power module to maintain the temperature of the power module at the module temperature.

[0011] In some embodiments, the specified target rotation speed is greater than the fan speed of the fan in the heat dissipation unit during the first operating state, and controlling the fan speed of the fan in the heat dissipation unit to maintain the temperature of the power module at the module temperature includes: increasing the power of the power module.

[0012] In some embodiments, the specified target rotation speed is less than the fan speed of the fan in the heat dissipation unit when the first operating state is reached, and the control of the fan speed of the fan in the heat dissipation unit to maintain the temperature of the power module at the module temperature includes: reducing the power of the power module.

[0013] In some embodiments, when the fan speed of the heat dissipation unit is changed to the specified target speed, the power module corresponds to an expected power change. The health status of the heat dissipation unit is determined based on the power of the power module and the fan speed of the heat dissipation unit in the first operating state, and the power of the power module and the fan speed of the heat dissipation unit in the second operating state. This includes: determining the power change between the power of the power module in the first operating state and the power in the second operating state; if the absolute value of the difference between the power change and the expected power change is less than a second specified threshold, the heat dissipation unit is considered to be in a normal state; or, if the absolute value of the difference between the power change and the expected power change is greater than the second specified threshold, the heat dissipation unit is considered to be in an abnormal state.

[0014] In some embodiments, during the first operating state, the fan speed of the fan in the heat dissipation unit is 0; or, during the second operating state, the fan speed of the fan in the heat dissipation unit is 0.

[0015] In some embodiments, the controller is further configured to reduce the upper limit of the output power of the power conversion device and / or reduce the temperature protection threshold of the power conversion device when it is determined that the heat dissipation unit is in an abnormal state.

[0016] This specification provides a method for determining the health status of a heat dissipation unit in a power conversion device. The power conversion device includes a power module, a heat dissipation unit, and a controller. The heat dissipation unit is used to dissipate heat from the power module. The method includes: when the power conversion device is in a first operating state, while maintaining the module temperature of the power module constant, controlling and changing the power of the power module and the fan speed of the fan in the heat dissipation unit to make the power conversion device enter a second operating state; determining the health status of the heat dissipation unit based on the power of the power module and the fan speed of the fan in the heat dissipation unit in the first operating state, and the power of the power module and the fan speed of the fan in the heat dissipation unit in the second operating state.

[0017] In some embodiments, the step of controlling the change of the power of the power module and the change of the fan speed of the fan in the heat dissipation unit to put the power conversion device into a second working state includes: when the controller controls the power of the power module to change to a specified target power, controlling the fan speed of the fan in the heat dissipation unit to maintain the temperature of the power module at the module temperature.

[0018] In some embodiments, the specified target power is less than the power of the power module in the first operating state; the step of controlling the fan speed of the fan in the heat dissipation unit to maintain the temperature of the power module at the module temperature includes: reducing the fan speed of the heat dissipation unit.

[0019] In some embodiments, the specified target power is greater than the power of the power module in the first operating state; the step of controlling the fan speed of the fan in the heat dissipation unit to maintain the temperature of the power module at the module temperature includes: increasing the fan speed of the heat dissipation unit.

[0020] In some embodiments, when the power of the power module is changed to the specified target power, the fan of the heat dissipation unit corresponds to a predicted speed change. The step of determining the health status of the heat dissipation unit based on the power of the power module and the fan speed of the heat dissipation unit in the first operating state, and the power of the power module and the fan speed of the heat dissipation unit in the second operating state, includes: determining the speed change between the fan speed of the heat dissipation unit in the first operating state and the fan speed in the second operating state; if the absolute value of the difference between the speed change and the predicted speed change is less than a first specified threshold, the heat dissipation unit is considered to be in a normal state; or, if the absolute value of the difference between the speed change and the predicted speed change is greater than the first specified threshold, the heat dissipation unit is considered to be in an abnormal state.

[0021] In some embodiments, the step of controlling the power of the power module and the fan speed of the heat dissipation unit to put the power conversion device into a second operating state includes: when the controller controls the fan speed of the heat dissipation unit to change to a specified target speed, controlling the power of the power module to maintain the temperature of the power module at the module temperature.

[0022] In some embodiments, the specified target rotation speed is greater than the fan speed of the fan in the heat dissipation unit during the first operating state, and the step of controlling the fan speed of the fan in the heat dissipation unit to maintain the temperature of the power module at the module temperature includes: increasing the power of the power module.

[0023] In some embodiments, the specified target rotation speed is less than the fan speed of the fan in the heat dissipation unit when the first operating state is reached, and the step of controlling the fan speed of the fan in the heat dissipation unit to maintain the temperature of the power module at the module temperature includes: reducing the power of the power module.

[0024] In some embodiments, when the fan speed of the heat dissipation unit is changed to the specified target speed, the power module corresponds to an expected power change. The step of determining the health status of the heat dissipation unit based on the power of the power module and the fan speed of the heat dissipation unit in the first operating state, and the power of the power module and the fan speed of the heat dissipation unit in the second operating state, includes: determining the power change between the power of the power module in the first operating state and the power in the second operating state; determining that the heat dissipation unit is in a normal state if the absolute value of the difference between the power change and the expected power change is less than a second specified threshold; or determining that the heat dissipation unit is in an abnormal state if the absolute value of the difference between the power change and the expected power change is greater than the second specified threshold.

[0025] In some embodiments, during the first operating state, the fan speed of the fan in the heat dissipation unit is 0; or, during the second operating state, the fan speed of the fan in the heat dissipation unit is 0.

[0026] In some embodiments, the method for determining the health status of the heat dissipation unit of the power conversion device further includes: reducing the upper limit of the output power of the power conversion device and / or reducing the temperature protection threshold of the power conversion device when it is determined that the heat dissipation unit is in an abnormal state.

[0027] This specification provides an energy system including the power conversion device described in any of the above embodiments.

[0028] In several embodiments provided in this specification, the power conversion device includes a power module, a heat dissipation unit, and a controller. The heat dissipation unit is used to dissipate heat from the power module. In the embodiments provided in this specification, the controller dynamically adjusts the power of the power module and the fan speed of the fan in the heat dissipation unit while maintaining a constant module temperature when the power conversion device is in a first operating state, thereby enabling the power conversion device to enter a second operating state. Furthermore, by comparing the power of the power module and the fan speed in the first and second operating states, the health status of the heat dissipation unit can be determined more accurately. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0030] Figure 1This is a schematic diagram of a power conversion device provided for one embodiment of this specification.

[0031] Figure 2 This is a flowchart illustrating a method for determining the health status of a heat dissipation unit in a power conversion device according to one embodiment of this specification.

[0032] Figure 3 This is a flowchart illustrating a method for determining the health status of a heat dissipation unit in a power conversion device according to one embodiment of this specification.

[0033] Figure 4 A schematic diagram of an energy system provided for one embodiment of this specification. Detailed Implementation

[0034] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0035] In the description of the embodiments of this application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0036] During the operation of a power converter, the power electronic components in the power module switch on and off at high frequencies, generating significant heat. Therefore, related technologies incorporate heat dissipation units within the power converter to cool the power module and maintain stable operation. Thus, accurate assessment of the heat dissipation unit's health status is crucial for the stable operation of the power converter.

[0037] In some related technologies, a thermal resistance model can be established using historical data describing the historical operating states of a power converter. Based on this model, the thermal resistance of the heat conduction path of the power module can be calculated, thereby determining the heat dissipation status of the power converter. However, this approach requires a large amount of historical data. When the amount of historical data is limited, the accuracy of the heat dissipation status of the power converter determined by this approach is not high.

[0038] Therefore, in this embodiment, the controller dynamically adjusts the power of the power module and the fan speed of the heat dissipation unit while maintaining a constant module temperature when the power conversion device is in the first operating state, thereby causing the power conversion device to enter the second operating state. By comparing the power of the power module and the fan speed in the first and second operating states, the health status of the heat dissipation unit can be determined more accurately.

[0039] Please see Figure 1 This specification provides a power conversion device. The power conversion device includes a power module, a heat dissipation unit, and a controller. The controller, when the power conversion device is in a first operating state, controls and changes the power of the power module and the fan speed of the fan in the heat dissipation unit while maintaining a constant module temperature, thereby causing the power conversion device to switch to a second operating state. Based on the power of the power module and the fan speed of the fan in the heat dissipation unit in the first operating state, and the power of the power module and the fan speed of the fan in the heat dissipation unit in the second operating state, the health status of the heat dissipation unit is determined.

[0040] A power conversion device is a device used to convert electrical energy into a different form. Specifically, a power conversion device can be a bidirectional inverter used to convert direct current (DC) to alternating current (AC). Of course, a power conversion device can also be a DC-DC converter used to convert DC to DC. For example, a DC-DC converter can boost or buck DC. In some embodiments, the power conversion device can be a photovoltaic inverter or an energy storage converter. This embodiment does not impose specific limitations.

[0041] In some embodiments, the power conversion device can be applied to any energy system such as a photovoltaic system, an energy storage system, or an integrated photovoltaic-energy storage system.

[0042] A power module is a module composed of multiple power electronic components. By controlling the opening and closing of the power electronic components inside the power module, the conversion of electrical energy can be achieved. These power electronic components include, but are not limited to, semiconductor switching elements such as insulated-gate bipolar transistors (IGBTs) or metal-oxide-semiconductor field-effect transistors (MOSFETs). This embodiment does not impose specific limitations.

[0043] The power module generates heat during operation. Specifically, the controller can adjust the power module's power output to change the amount of heat generated, thereby affecting the power module's temperature.

[0044] The power conversion device also includes a heat dissipation unit. The heat dissipation unit can be used to guide the heat from the power module out of the power conversion device. Specifically, the heat dissipation unit may include a fan. In some embodiments, the heat dissipation unit may also include one or more components such as air ducts and heat sinks. The controller can change the heat dissipation capacity of the heat dissipation unit by adjusting the fan speed in the heat dissipation unit, thereby affecting the temperature of the power module.

[0045] The health status of the heat dissipation unit includes whether the components in the heat dissipation unit are damaged, or whether the air ducts in the heat dissipation unit used to guide heat out of the power conversion device are blocked.

[0046] A controller is a control device used to control the operating status of a power conversion device or to acquire status data of the power conversion device. Specifically, a controller can be used to control the operating status of the power module and the heat dissipation unit, and to acquire status data such as the power and temperature of the power module and the fan speed of the fan in the heat dissipation unit.

[0047] The power module has a module temperature. Module temperature can represent the temperature of the power module when the power conversion device is in its first operating state. For example, the module temperature can be the surface temperature of the power module detected by a temperature sensor built into the power conversion device.

[0048] The controller can maintain the module temperature of the power module by changing the power of the power module and the fan speed of the fan in the heat dissipation unit when the power conversion device is in the first working state.

[0049] When the power of the power module and the fan speed of the heat dissipation unit in the power conversion device change and reach a balance, such that the temperature of the power module is the same as the module temperature in the first working state, the working state of the power conversion device can be regarded as the second working state.

[0050] In some embodiments, when the power conversion device is in the first operating state, the controller can first obtain the module temperature of the power module through the temperature detection device, and then, while maintaining the module temperature of the power module unchanged, control the power of the power module and the fan speed of the fan in the heat dissipation unit to change the power conversion device to the second operating state.

[0051] In some embodiments, the first operating state can be a preset operating state. In the first operating state, the power module has a preset power, and the fan in the heat dissipation unit has a preset fan speed. Thus, after the power conversion device changes to the second operating state, the controller can determine the health status of the heat dissipation unit by measuring the power of the power module and the fan speed in the second operating state, and combining this with the preset power of the power module and the preset fan speed in the first operating state.

[0052] Of course, to more accurately determine the health status of the heat dissipation unit, the controller can also determine the health status of the heat dissipation unit by measuring the power of the power module and the measured fan speed in the first operating state, and by measuring the power of the power module and the measured fan speed in the second operating state. This embodiment does not impose specific limitations here. In some embodiments, controlling the change of the power of the power module and the change of the fan speed in the heat dissipation unit to switch the power conversion device to the second operating state includes: when the controller controls the power of the power module to change to a specified target power, controlling the fan speed in the heat dissipation unit to maintain the temperature of the power module at the module temperature.

[0053] When the power conversion device is in its first operating state, the controller can control the power conversion of the power module to a specified target power. Correspondingly, to maintain a constant module temperature, the controller also needs to control the fan speed in the heat dissipation unit.

[0054] The specified target power can be a preset power value. Of course, the specified target power can also be determined by instructions issued by other devices. This embodiment does not impose specific limitations here.

[0055] In some embodiments, the controller can use an automatic control algorithm to adjust the fan speed in the heat dissipation unit based on the difference between the power module temperature after the power change and the power module temperature in the first operating state, so that the power module temperature reaches the module temperature in the first operating state. The automatic control algorithm includes, but is not limited to, PID control algorithms, fuzzy control algorithms, or adaptive control algorithms.

[0056] Since the target power is fixed, the fan speed in the heat dissipation unit is adjusted by an automatic control algorithm. Therefore, after switching to the second operating state, the controller can simply obtain the measured fan speed and combine it with the target power, the power of the power module in the first operating state, and the fan speed in the heat dissipation unit to determine the health status of the heat dissipation unit.

[0057] Of course, in order to more accurately determine the health status of the heat dissipation unit, the controller can also obtain the measured power of the power module and the measured fan speed after switching to the second working state, so as to determine the health status of the heat dissipation unit.

[0058] In some embodiments, specifying a target power less than the power of the power module in the first operating state; controlling the fan speed of the fan in the heat dissipation unit to maintain the temperature of the power module at the module temperature includes: reducing the fan speed of the heat dissipation unit.

[0059] In the second operating state, when the power of the power module is lower than that in the first operating state, the heat generated by the power module decreases. Correspondingly, the controller can maintain a constant module temperature by reducing the fan speed of the heat dissipation unit. In other words, the controller can maintain a constant module temperature by reducing the heat dissipation capacity of the heat dissipation unit.

[0060] In some embodiments, the controller may reduce the fan speed of the heat dissipation unit based on a specified step size until the temperature of the power module reaches the module temperature.

[0061] In some embodiments, specifying a target power greater than the power of the power module in the first operating state, and controlling the fan speed of the fan in the heat dissipation unit to maintain the temperature of the power module at the module temperature, includes: increasing the fan speed of the heat dissipation unit.

[0062] In the second operating state, when the power module's power is higher than in the first operating state, the power module generates more heat. Correspondingly, the controller can maintain a constant module temperature by increasing the fan speed of the cooling unit. In other words, the controller can maintain a constant module temperature by increasing the heat dissipation capacity of the cooling unit.

[0063] In some embodiments, the controller can increase the fan speed of the heat dissipation unit by a specified step size until the temperature of the power module reaches the module temperature.

[0064] In some embodiments, the specified step size for the fan speed can be 1 revolution per second, 10 revolutions per second, 50 revolutions per second, or 100 revolutions per second, etc. In some embodiments, the specified step size for the fan speed can also gradually decrease as the temperature difference between the power module and the module temperature decreases. This specification does not specifically limit this aspect in the embodiments.

[0065] In some embodiments, when the power of the power module is changed to a specified target power, the fan of the heat dissipation unit corresponds to a predicted change in speed. The health status of the heat dissipation unit is determined based on the power of the power module and the fan speed of the heat dissipation unit in a first operating state, and the power of the power module and the fan speed of the heat dissipation unit in a second operating state. This includes: determining the change in fan speed between the first and second operating states; if the absolute value of the difference between the change in speed and the predicted change in speed is less than a first specified threshold, the heat dissipation unit is considered to be in a normal state; or, if the absolute value of the difference between the change in speed and the predicted change in speed is greater than the first specified threshold, the heat dissipation unit is considered to be in an abnormal state.

[0066] The expected change in rotational speed can be expressed as the expected change in the fan speed of the cooling unit when the power module adjusts from its first operating state to a specified target power, in order to maintain a constant module temperature, under normal conditions.

[0067] The first specified threshold is a numerical value used to measure the difference between the change in fan speed in the cooling unit and the expected change in fan speed when the power conversion device changes from a first operating state to a second operating state. If the absolute value of the difference between the change in fan speed and the expected change in fan speed is less than the first specified threshold, the difference can be considered negligible. Accordingly, the controller can determine that the cooling unit is in a normal state.

[0068] When the absolute value of the difference between the change in rotational speed and the expected change in rotational speed exceeds a first specified threshold, a discrepancy can be considered to exist between the two. Accordingly, the controller can determine that the heat dissipation unit is in an abnormal state. At this time, maintenance personnel of the power converter can promptly maintain and repair the heat dissipation unit to reduce the risk of damage to the power converter and ensure its stable operation.

[0069] In some embodiments, controlling the power of the power module and the fan speed of the heat dissipation unit to change the power conversion device to a second operating state includes: when the controller controls the fan speed of the heat dissipation unit to change to a specified target speed, controlling the power of the power module to maintain the temperature of the power module at the module temperature.

[0070] When the power conversion device is in its first operating state, the controller can control the fan speed in the heat dissipation unit to change to a specified target speed. Correspondingly, in order to maintain a constant module temperature, the controller also needs to control the power of the power module.

[0071] The specified target speed can be a preset fan speed value. Of course, the specified target speed can also be determined by a command issued by other devices. This embodiment does not impose specific limitations here.

[0072] In some embodiments, the controller can use an automatic control algorithm to adjust the power of the power module based on the difference between the temperature of the power module after the fan speed is changed to a specified target speed and the module temperature of the power module in the first operating state, so that the temperature of the power module reaches the module temperature in the first operating state. The automatic control algorithm includes, but is not limited to, PID control algorithms, fuzzy control algorithms, or adaptive control algorithms.

[0073] Since the target rotational speed is fixed, the power of the power module is adjusted by an automatic control algorithm. Therefore, after switching to the second operating state, the controller can obtain only the measured power of the power module and combine it with the target rotational speed, the power of the power module in the first operating state, and the fan speed of the fan in the heat dissipation unit to determine the health status of the heat dissipation unit.

[0074] Of course, in order to more accurately determine the health status of the heat dissipation unit, the controller can also obtain the measured power of the power module and the measured fan speed after switching to the second working state, so as to determine the health status of the heat dissipation unit.

[0075] In some embodiments, specifying a target rotation speed greater than the fan speed of the fan in the heat dissipation unit during the first operating state, and controlling the fan speed of the fan in the heat dissipation unit to maintain the temperature of the power module at the module temperature, includes: increasing the power of the power module.

[0076] In the second operating state, when the fan speed in the heat dissipation unit is higher than that in the first operating state, the heat dissipation capacity of the heat dissipation unit increases. Correspondingly, the controller can maintain a constant power module temperature by increasing the power module's power output. That is, the controller can increase the heat generated by the power module to maintain a constant power module temperature.

[0077] In some embodiments, the controller may increase the power of the power module in specified steps until the power module reaches the module temperature.

[0078] In some embodiments, specifying a target rotation speed less than the fan speed of the fan in the heat dissipation unit when the first operating state is used, and controlling the fan speed of the fan in the heat dissipation unit to maintain the temperature of the power module at the module temperature includes: reducing the power of the power module.

[0079] In the second operating state, when the fan speed in the heat dissipation unit is lower than that in the first operating state, the heat dissipation capacity of the heat dissipation unit decreases. Correspondingly, the controller can maintain a constant power module temperature by reducing the power module's power output. That is, the controller can reduce the heat generated by the power module to maintain a constant power module temperature.

[0080] In some embodiments, the controller may reduce the power of the power module in specified steps until the power module temperature reaches the module temperature.

[0081] In some embodiments, the specified power step size of the power module can be 10 watts, 50 watts, 100 watts, 1 kilowatt, 5 kilowatts, or 1 megawatt, etc. In some embodiments, the specified power step size can also gradually decrease as the temperature difference between the power module and the module temperature decreases. This specification does not specifically limit this aspect in the embodiments.

[0082] In some embodiments, when the fan speed of the heat dissipation unit changes to a specified target speed, the power module has a corresponding expected power change. The health status of the heat dissipation unit is determined based on the power of the power module and the fan speed of the heat dissipation unit in a first operating state, and the power of the power module and the fan speed of the heat dissipation unit in a second operating state. This includes: determining the power change between the power of the power module in the first operating state and the power in the second operating state; if the absolute value of the difference between the power change and the expected power change is less than a second specified threshold, the heat dissipation unit is considered to be in a normal state; or, if the absolute value of the difference between the power change and the expected power change is greater than the second specified threshold, the heat dissipation unit is considered to be in an abnormal state.

[0083] The expected power change can be represented as the expected power change of the power module in order to maintain a constant module temperature when the fan speed in the heat dissipation unit is adjusted from the fan speed in the first working state to the specified target speed, under normal conditions.

[0084] The second specified threshold is a numerical value used to measure the difference between the power change of the power module and the expected power change when the power conversion device changes from the first operating state to the second operating state. When the absolute value of the difference between the power change and the expected power change is less than the second specified threshold, the difference can be considered negligible. Accordingly, the controller can determine that the heat dissipation unit is in a normal state.

[0085] When the absolute value of the difference between the power change and the expected power change exceeds a second specified threshold, a discrepancy can be considered established. Accordingly, the controller can determine that the heat dissipation unit is in an abnormal state. At this time, maintenance personnel of the power converter can promptly maintain and repair the heat dissipation unit to reduce the risk of damage to the power converter and ensure its stable operation.

[0086] In some embodiments, in the first operating state, the fan speed of the fan in the heat dissipation unit is 0; or, in the second operating state, the fan speed of the fan in the heat dissipation unit is 0.

[0087] When the power conversion device switches from the first operating state to the second operating state, if the fan speed change in the heat dissipation unit is small, the power conversion value of the power module may also be small in order to maintain a constant module temperature. This can lead to a large error when comparing the actual power conversion value with the expected power conversion value. Therefore, the fan speed in the heat dissipation unit can be set to 0 in the first operating state, or the fan speed in the heat dissipation unit can be set to 0 in the second operating state. This increases the difference in fan speed between the first and second operating states, thereby improving the accuracy of the health status assessment of the heat dissipation unit.

[0088] In some embodiments, the controller is further configured to reduce the upper limit of the output power of the power conversion device and / or reduce the temperature protection threshold of the power conversion device when the heat dissipation unit is determined to be in an abnormal state. This reduces the heat generated by the power module, thereby alleviating the burden on the heat dissipation unit.

[0089] The upper limit of output power indicates the maximum output power that the power conversion device is set to operate at. Lowering the upper limit of the power conversion device's output power can, to some extent, ensure that the heat generated during operation is not excessive, thereby preventing damage to the internal components of the device.

[0090] Lowering the temperature protection threshold of the power converter means that the protection mechanism will be triggered at a lower temperature, thereby reducing the risk of damage to the power converter due to temperature rise.

[0091] In summary, when the controller determines that the heat dissipation unit is in an abnormal state, it can reduce the risk of damage to the internal components of the power conversion device due to the abnormal state of the heat dissipation unit by one or more means, such as reducing the upper limit of the output power of the power conversion device and reducing the temperature protection threshold of the power conversion device.

[0092] This specification also provides a method for determining the health status of a heat dissipation unit in a power conversion device. The power conversion device includes a power module, a heat dissipation unit, and a controller. The heat dissipation unit is used to dissipate heat from the power module. The method includes: when the power conversion device is in a first operating state, while maintaining the module temperature of the power module constant, controlling and changing the power of the power module and the fan speed of the fan in the heat dissipation unit to change the power conversion device to a second operating state; determining the health status of the heat dissipation unit based on the power of the power module and the fan speed of the fan in the heat dissipation unit in the first operating state, and the power of the power module and the fan speed of the fan in the heat dissipation unit in the second operating state.

[0093] Please see Figure 2 The method for determining the health status of the heat dissipation unit of the power conversion device in one embodiment provided in this specification includes the following steps.

[0094] Step S110: The power conversion device is in operation.

[0095] Step S120: In the first working state, acquire the power of the power module, the module temperature, and the fan speed of the fan in the heat dissipation unit.

[0096] Step S130: While maintaining the module temperature of the power module constant, change the power of the power module and the fan speed of the fan in the heat dissipation unit to achieve the second working state.

[0097] Step S140: Determine the health status of the heat dissipation unit based on the power of the power module and the fan speed of the fan in the heat dissipation unit during the first operating state, and the power of the power module and the fan speed of the fan in the heat dissipation unit during the second operating state.

[0098] In some embodiments, the step of controlling the power of the power module and the fan speed of the fan in the heat dissipation unit to change the power conversion device to a second operating state includes: when the controller controls the power of the power module to change to a specified target power, controlling the fan speed of the fan in the heat dissipation unit to maintain the temperature of the power module at the module temperature.

[0099] In some embodiments, specifying a target power less than the power of the power module in the first operating state; controlling the fan speed of the fan in the heat dissipation unit to maintain the temperature of the power module at the module temperature includes: reducing the fan speed of the heat dissipation unit.

[0100] In some embodiments, specifying a target power greater than the power of the power module in the first operating state; controlling the fan speed of the fan in the heat dissipation unit to maintain the temperature of the power module at the module temperature includes: increasing the fan speed of the heat dissipation unit.

[0101] In some embodiments, when the power of the power module is changed to a specified target power, the fan of the heat dissipation unit corresponds to a predicted change in speed. The health status of the heat dissipation unit is determined based on the power of the power module and the fan speed of the heat dissipation unit in a first operating state, and the power of the power module and the fan speed of the heat dissipation unit in a second operating state. This includes: determining the change in fan speed between the first and second operating states; if the absolute value of the difference between the change in speed and the predicted change in speed is less than a first specified threshold, the heat dissipation unit is considered to be in a normal state; or, if the absolute value of the difference between the change in speed and the predicted change in speed is greater than the first specified threshold, the heat dissipation unit is considered to be in an abnormal state.

[0102] In some embodiments, the step of controlling the power of the power module and the fan speed of the heat dissipation unit to change the power conversion device to a second operating state includes: when the controller controls the fan speed of the heat dissipation unit to change to a specified target speed, controlling the power of the power module to maintain the temperature of the power module at the module temperature.

[0103] In some embodiments, the step of specifying a target rotation speed greater than the fan speed of the fan in the heat dissipation unit in the first operating state, and controlling the fan speed of the fan in the heat dissipation unit to maintain the temperature of the power module at the module temperature, includes: increasing the power of the power module.

[0104] In some embodiments, the step of specifying a target rotation speed less than the fan speed of the fan in the heat dissipation unit when the first operating state is used, and controlling the fan speed of the fan in the heat dissipation unit to maintain the temperature of the power module at the module temperature, includes: reducing the power of the power module.

[0105] In some embodiments, when the fan speed of the heat dissipation unit changes to a specified target speed, the power module has a corresponding expected power change. The step of determining the health status of the heat dissipation unit based on the power of the power module and the fan speed of the heat dissipation unit in the first operating state, and the power of the power module and the fan speed of the heat dissipation unit in the second operating state, includes: determining the power change between the power of the power module in the first operating state and the power in the second operating state; determining that the heat dissipation unit is in a normal state if the absolute value of the difference between the power change and the expected power change is less than a second specified threshold; or determining that the heat dissipation unit is in an abnormal state if the absolute value of the difference between the power change and the expected power change is greater than the second specified threshold.

[0106] In some embodiments, in the first operating state, the fan speed of the fan in the heat dissipation unit is 0; or, in the second operating state, the fan speed of the fan in the heat dissipation unit is 0.

[0107] Please see Figure 3 The method for determining the health status of the heat dissipation unit of the power conversion device in one embodiment provided in this specification includes the following steps.

[0108] Step S210: The power conversion device is in operation.

[0109] Step S220: In the first working state, the fan speed of the fan in the heat dissipation unit is controlled to 0, and the power and module temperature of the power module are obtained.

[0110] Step S230: While maintaining the module temperature of the power module constant, change the power of the power module and the fan speed of the fan in the heat dissipation unit to achieve the second working state.

[0111] Step S240: Determine the health status of the heat dissipation unit based on the power of the power module and the fan speed of the fan in the heat dissipation unit during the first operating state, and the power of the power module and the fan speed of the fan in the heat dissipation unit during the second operating state.

[0112] In some embodiments, the method for determining the health status of the heat dissipation unit of the power conversion device further includes: reducing the upper limit of the output power of the power conversion device and / or reducing the temperature protection threshold of the power conversion device when it is determined that the heat dissipation unit is in an abnormal state.

[0113] For a description of the method for determining the health status of the heat dissipation unit of the power conversion device, please refer to other embodiments in this specification. This embodiment will not be elaborated further here.

[0114] Please see Figure 4 This specification also provides an energy system. The energy system includes a power conversion device as described in any of the embodiments of this specification. The DC side of the power conversion device can be connected to a DC source. The AC side of the power conversion device can be connected to a power grid.

[0115] For a description of the energy system, please refer to other embodiments in this specification. This embodiment will not be elaborated further here.

[0116] It is understood that the term "connection" in the following embodiments should be understood as "electrical connection," "communication connection," etc., if the connected circuits, modules, units, etc. can transmit electrical signals or data to each other.

[0117] It is understood that the specific examples in this document are only intended to help those skilled in the art better understand the embodiments of this specification, and are not intended to limit the scope of the invention.

[0118] It is understood that in the various embodiments of this specification, the sequence number of each process does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this specification.

[0119] It is understood that the various embodiments described in this specification can be implemented individually or in combination, and the embodiments in this specification are not limited in this respect.

[0120] Unless otherwise stated, all technical and scientific terms used in the embodiments of this specification have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of this specification. The term "and / or" as used in this specification includes any and all combinations of one or more of the associated listed items. The singular forms "a," "the," and "the" as used in the embodiments of this specification and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0121] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this specification.

[0122] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0123] As should be understood from the several embodiments provided in this specification, the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and 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 through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0124] 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.

[0125] The above description is merely a specific embodiment of this specification, but the scope of protection of this invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this specification should be included within the scope of protection of this specification. Therefore, the scope of protection of this invention should be determined by the scope of the claims.

Claims

1. A power conversion device, characterized by, The power module, the heat dissipation unit and the controller; the heat dissipation unit is used for dissipating heat for the power module; The controller is used for controlling the change of the power of the power module and the change of the fan rotating speed of the fan in the heat dissipation unit under the condition of maintaining the module temperature of the power module unchanged when the power conversion device is in the first working state, so that the power conversion device changes to the second working state; according to the power of the power module and the fan rotating speed of the fan in the heat dissipation unit in the first working state and the power of the power module and the fan rotating speed of the fan in the heat dissipation unit in the second working state, the health status of the heat dissipation unit is determined. The control of the change of the power of the power module and the change of the fan rotating speed of the fan in the heat dissipation unit so that the power conversion device is in the second working state comprises:

2. The power conversion device of claim 1, wherein, In the case that the controller controls the power of the power module to change to a specified target power, the fan rotating speed of the fan in the heat dissipation unit is controlled so that the temperature of the power module is maintained at the module temperature. The specified target power is less than the power of the power module in the first working state; the control of the fan rotating speed of the fan in the heat dissipation unit so that the temperature of the power module is maintained at the module temperature comprises: reducing the fan rotating speed of the heat dissipation unit.

3. The power conversion device of claim 2, wherein, The specified target power is greater than the power of the power module in the first working state, and the control of the fan rotating speed of the fan in the heat dissipation unit so that the temperature of the power module is maintained at the module temperature comprises: increasing the fan rotating speed of the heat dissipation unit.

4. The power conversion device of claim 2, wherein, The power of the power module changes to the specified target power, and the fan of the heat dissipation unit corresponds to a predicted rotating speed change amount; 5. The power conversion device of claim 2, wherein, According to the power of the power module and the fan rotating speed of the heat dissipation unit in the first working state and the power of the power module and the fan rotating speed of the heat dissipation unit in the second working state, the health status of the heat dissipation unit is determined, which comprises: determining the rotating speed change amount between the fan rotating speed of the fan of the heat dissipation unit in the first working state and the fan rotating speed of the fan in the second working state; in the case that the absolute value of the difference between the rotating speed change amount and the predicted rotating speed change amount is less than a first specified threshold, it is determined that the heat dissipation unit is in a normal state; or in the case that the absolute value of the difference between the rotating speed change amount and the predicted rotating speed change amount is greater than the first specified threshold, it is determined that the heat dissipation unit is in an abnormal state. The control of the change of the power of the power module and the change of the fan rotating speed of the fan in the heat dissipation unit so that the power conversion device is in the second working state comprises:

6. The power conversion device of claim 1, wherein, In the case that the controller controls the fan rotating speed of the heat dissipation unit to change to a specified target rotating speed, the power of the power module is controlled so that the temperature of the power module is maintained at the module temperature. ​ 7. The power conversion device of claim 6, wherein, The specified target rotation speed is greater than the fan speed of the fan in the heat dissipation unit when the first working state is reached. The step of controlling the fan speed of the fan in the heat dissipation unit to maintain the temperature of the power module at the module temperature includes: increasing the power of the power module.

8. The power conversion device of claim 6, wherein, The specified target rotation speed is less than the fan speed of the fan in the heat dissipation unit when the first working state is reached. The step of controlling the fan speed of the fan in the heat dissipation unit to maintain the temperature of the power module at the module temperature includes: reducing the power of the power module.

9. The power conversion device of claim 6, wherein, When the fan speed of the heat dissipation unit is changed to the specified target speed, the power module has a corresponding expected power change. Determining the health status of the heat dissipation unit based on the power of the power module and the fan speed of the heat dissipation unit in the first operating state, and the power of the power module and the fan speed of the heat dissipation unit in the second operating state, includes: determining the power change between the power of the power module in the first operating state and the power in the second operating state; determining that the heat dissipation unit is in a normal state if the absolute value of the difference between the power change and the expected power change is less than a second specified threshold; or determining that the heat dissipation unit is in an abnormal state if the absolute value of the difference between the power change and the expected power change is greater than the second specified threshold.

10. The power conversion device of claim 1, wherein, In the first operating state, the fan speed of the fan in the heat dissipation unit is 0; or, in the second operating state, the fan speed of the fan in the heat dissipation unit is 0.

11. The power conversion device according to any one of claims 1 to 10, characterized in that, The controller is also configured to reduce the upper limit of the output power of the power conversion device and / or reduce the temperature protection threshold of the power conversion device when the heat dissipation unit is determined to be in an abnormal state.

12. A method of determining a health state of a cooling unit of a power conversion device, characterized by, The power conversion device includes a power module, a heat dissipation unit, and a controller; the heat dissipation unit is used to dissipate heat from the power module; the method includes: When the power conversion device is in the first working state, while maintaining the module temperature of the power module constant, the power of the power module and the fan speed of the fan in the heat dissipation unit are controlled to change, so that the power conversion device is in the second working state. The health status of the heat dissipation unit is determined based on the power of the power module and the fan speed of the fan in the heat dissipation unit during the first operating state, and the power of the power module and the fan speed of the fan in the heat dissipation unit during the second operating state.

13. The method of claim 12, wherein, The steps of controlling and changing the power of the power module and the fan speed of the fan in the heat dissipation unit to put the power conversion device into a second operating state include: When the controller controls the power module to change to a specified target power, the fan speed of the fan in the heat dissipation unit is controlled so that the temperature of the power module is maintained at the module temperature.

14. The method of claim 13, wherein, The specified target power is less than the power of the power module in the first operating state; controlling the fan speed in the heat dissipation unit to maintain the temperature of the power module at the module temperature includes: Reduce the fan speed of the heat dissipation unit.

15. The method of claim 13, wherein, The specified target power is greater than the power of the power module in the first operating state; controlling the fan speed in the heat dissipation unit to maintain the temperature of the power module at the module temperature includes: Increase the fan speed of the heat dissipation unit.

16. The method of claim 13, wherein, When the power of the power module changes to the specified target power, the fan of the heat dissipation unit corresponds to a predicted speed change. Based on the power of the power module and the fan speed of the heat dissipation unit in the first operating state, and the power of the power module and the fan speed of the heat dissipation unit in the second operating state, the health status of the heat dissipation unit is determined, including: Determine the change in fan speed between the fan speed of the heat dissipation unit in the first working state and the fan speed in the second working state; If the absolute value of the difference between the change in rotational speed and the expected change in rotational speed is less than a first specified threshold, the heat dissipation unit is considered to be in a normal state; or, if the absolute value of the difference between the change in rotational speed and the expected change in rotational speed is greater than the first specified threshold, the heat dissipation unit is considered to be in an abnormal state.

17. The method of claim 12, wherein, The step of controlling and changing the power of the power module and the fan speed of the heat dissipation unit to put the power conversion device into a second operating state includes: When the controller controls the fan speed of the heat dissipation unit to change to a specified target speed, the power of the power module is controlled so that the temperature of the power module is maintained at the module temperature.

18. The method of claim 17, wherein, The specified target rotational speed is greater than the fan speed of the fan in the heat dissipation unit during the first operating state. The step of controlling the fan speed of the fan in the heat dissipation unit to maintain the temperature of the power module at the module temperature includes: Increase the power of the power module.

19. The method of claim 17, wherein, The step of controlling the fan speed of the heat dissipation unit to maintain the temperature of the power module at the module temperature, wherein the specified target rotation speed is less than the fan speed of the fan in the heat dissipation unit during the first operating state, includes: Reduce the power of the power module.

20. The method of claim 17, wherein, The step of determining the health status of the heat dissipation unit based on the power of the power module and the fan speed of the heat dissipation unit in the first operating state, and the power of the power module and the fan speed of the heat dissipation unit in the second operating state, includes: Determine the power change between the power of the power module in the first operating state and the power in the second operating state; If the absolute value of the difference between the power change and the expected power change is less than a second specified threshold, the heat dissipation unit is considered to be in a normal state; or, if the absolute value of the difference between the power change and the expected power change is greater than the second specified threshold, the heat dissipation unit is considered to be in an abnormal state.

21. The method according to claim 12, characterized in that, In the first operating state, the fan speed in the heat dissipation unit is 0; or, In the second operating state, the fan speed of the heat dissipation unit is 0.

22. The method according to any one of claims 12 to 21, characterized in that, The method further includes: If the heat dissipation unit is determined to be in an abnormal state, the upper limit of the output power of the power conversion device shall be reduced, and / or the temperature protection threshold of the power conversion device shall be reduced.

23. An energy system, comprising: include: The power conversion device as described in any one of claims 1 to 11.

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