Power conversion device

Abstract

The present invention relates to a power conversion device capable of efficiently controlling a fan module, the power conversion device comprising: a housing which accommodates a plurality of elements for performing power conversion; a plurality of fans mounted on the housing; a plurality of temperature measurement elements for measuring the temperatures of a plurality of temperature measurement points inside the housing, each corresponding to the mounting positions of the plurality of fans; a power supply unit for supplying individual power to the plurality of fans; and a control unit for performing PWM control of the plurality of fans.

Description

power conversion device

[0001] The present invention relates to a power conversion device, and more specifically, to a power conversion device capable of efficient fan module control.

[0002] Rapid chargers for electric vehicles support high-speed charging at hundreds of kilowatts. They consist of power modules with capacities of tens of kilowatts, connected in parallel, and output a large amount of power. When connected to an electric vehicle, the power modules receive AC power from the grid and output DC power to charge the electric vehicle's battery.

[0003] Power conversion within a power module generates significant heat. The power conversion efficiency of a power module is significantly affected by heat, making heat dissipation crucial. Air-cooling, which uses airflow to reduce heat, is commonly used for heat dissipation. Therefore, the development of technology to efficiently perform this air-cooling process is essential.

[0004] The technical problem to be solved by the present invention is to provide a power conversion device capable of efficient fan module control.

[0005] In order to solve the above technical problem, a power conversion device according to one embodiment of the present invention includes a housing that accommodates a plurality of elements that perform power conversion; a plurality of fans mounted on the housing; a plurality of temperature measurement elements that each measure the temperature of a plurality of temperature measurement points inside the housing, each corresponding to a mounting position of the plurality of fans; a power supply unit that supplies individual power to the plurality of fans; and a control unit that PWM controls the plurality of fans.

[0006] In addition, the control unit can individually control the plurality of fans by using the respective temperatures of the plurality of temperature measurement points measured by the plurality of temperature measurement elements and the differences between the respective temperatures.

[0007] Additionally, the control unit can apply a PWM signal having the same duty to the plurality of fans when the difference between the temperatures of the plurality of temperature measurement points is less than or equal to a first value.

[0008] In addition, the control unit may apply a PWM signal having a higher duty than other fans to a fan corresponding to a temperature measurement point having the highest temperature among the plurality of temperature measurement points when the difference between the temperatures of the plurality of temperature measurement points is greater than a first value.

[0009] Additionally, the control unit can apply a PWM signal having a maximum duty to a fan corresponding to a temperature measurement point having the highest temperature among the plurality of temperature measurement points.

[0010] In addition, the device includes a failure detection unit that detects a failure of the plurality of fans, and the control unit can control the plurality of fans according to a signal from the failure detection unit.

[0011] In addition, the control unit can stop the operation of a fan among the plurality of fans that has received a fault signal from the fault detection unit, and operate a fan among the plurality of fans that has not received a fault signal from the fault detection unit according to the temperature measured by the plurality of temperature measuring devices.

[0012] In addition, the power supply unit may include a plurality of power conversion units that are connected to each of the plurality of fans and supply the individual power, and may include a monitoring unit that monitors information of the plurality of power conversion units.

[0013] In addition, the control unit includes an auxiliary power supply unit that supplies power, and the power supply unit can convert power supplied from the auxiliary power supply unit and supply it to each of the plurality of fans.

[0014] Additionally, the plurality of temperature measuring elements may include an NTC element or a PTC element.

[0015] According to embodiments of the present invention, the performance of a power module can be improved.

[0016] FIG. 1 illustrates a power conversion device according to one embodiment of the present invention.

[0017] Figures 2 to 4 are block diagrams of a power conversion device according to an embodiment of the present invention.

[0018] Figures 5 to 7 are drawings for explaining a power conversion device according to an embodiment of the present invention.

[0019] Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the attached drawings.

[0020] However, the technical idea of ​​the present invention is not limited to some of the embodiments described, but can be implemented in various different forms, and within the scope of the technical idea of ​​the present invention, one or more of the components between the embodiments can be selectively combined or substituted for use.

[0021] In addition, terms (including technical and scientific terms) used in the embodiments of the present invention may be interpreted as having a meaning that can be generally understood by a person of ordinary skill in the technical field to which the present invention belongs, unless explicitly and specifically defined and described, and terms that are commonly used, such as terms defined in a dictionary, may be interpreted in consideration of the contextual meaning of the relevant technology.

[0022] Additionally, the terms used in the embodiments of the present invention are intended to describe the embodiments and are not intended to limit the present invention.

[0023] In this specification, the singular may also include the plural unless specifically stated otherwise in the phrase, and when it is described as “A and / or at least one (or more) of B, C”, it may include one or more of all combinations that can be combined with A, B, C.

[0024] Additionally, in describing components of embodiments of the present invention, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are only intended to distinguish the components from other components, and are not intended to limit the nature, order, or sequence of the components.

[0025] And, when a component is described as being 'connected', 'coupled', or 'connected' to another component, it may include not only cases where the component is 'connected', 'coupled', or 'connected' directly to the other component, but also cases where the component is 'connected', 'coupled', or 'connected' by another component between the component and the other component.

[0026] Additionally, when described as being formed or arranged "above" or "below" each component, "above" or "below" includes not only cases where the two components are in direct contact with each other, but also cases where one or more other components are formed or arranged between the two components. Furthermore, when expressed as "above" or "below," the meaning may include not only the upward direction but also the downward direction based on one component.

[0027] Fig. 1 illustrates a power conversion device according to an embodiment of the present invention. Figs. 2 to 4 are block diagrams of a power conversion device according to an embodiment of the present invention, and Figs. 5 to 7 are drawings for explaining a power conversion device according to an embodiment of the present invention.

[0028] A power conversion device (100) according to an embodiment of the present invention is composed of a housing (110), a power conversion element (120), a fan (140), a temperature measuring element (150), a power supply unit (160), and a control unit (170), and may include a fault detection unit (144), a monitoring unit (164), and a power conversion unit (161).

[0029] A power conversion device (100) according to an embodiment of the present invention may be a power conversion device of an electric vehicle charging device. Here, the power conversion device (100) may be a power module of the electric vehicle charging device. The power module may receive AC power from a grid (50 / 60 Hz), convert it into DC power for charging an electric vehicle battery, and output it. Alternatively, the power module may receive DC power from an energy storage system (ESS), convert it into DC power for charging a battery, and output it. Power may be received from an external power source such as a solar power generation module. The power module may include an AC-DC rectifier and a DC-DC converter, and the power conversion device (100) according to an embodiment of the present invention may include an isolated DC-DC converter or a non-isolated converter. Among the isolated DC-DC converters, the power conversion device may include a PSFB (Phase Shift Full Bridge) converter, an LLC resonant converter, a CLLC resonant converter, and a DAB (Dual Active Bridge) converter. Non-isolated DC-DC converters may include buck converters, boost converters, and buck-boost converters.

[0030] The power conversion element (120) and other elements or components included in the power conversion device (100) are arranged within a receiving space inside the housing (110). The housing (110) may include a housing forming an internal space and a cover covering the housing.

[0031] The power conversion element (120) can convert and output power input to the power conversion device (100). The power conversion element (120) can include an AC-DC rectifier, a DC-DC converter, or an AC-DC inverter. The power conversion element (120) can include one or more switching elements, and the switching elements can be semiconductor elements such as MOSFETs. Semiconductor elements generate a lot of heat during switching operation, and switching efficiency is greatly affected by temperature, so heat dissipation is important.

[0032] A fan (140) is formed on at least one surface of the housing (110) to allow air to flow into the housing (110) or to discharge air inside the housing (110) to the outside. The fan can create an airflow inside the housing (110) to reduce heat generated from heat generating elements, such as switching elements included in power conversion elements, disposed inside the housing (110). The fan (140) may be a DC fan operated by DC power, and the fan (140) may include a plurality of fans. The fan (140) may include two or more fans, or three fans. The plurality of fans (141, 142, 143) may be arranged in a row on one surface of the side plate of the housing (110), or may include a plurality of fans arranged at different positions. Each fan (141, 142, 143) corresponds to a direction in which air is introduced, and a heat generating element greatly affected by each fan may vary depending on the direction in which the air is introduced.

[0033] The power supply unit (160) can supply power required to drive the fan (140). The power supply unit (160) can receive power from the auxiliary power supply unit (180) and supply the input power as individual power to each of the plurality of fans (141, 142, 143). As shown in FIG. 4, the auxiliary power supply unit (180) can supply driving power to the power supply unit (160) or the control unit (170), and the power supply unit (160) can convert and supply individual power to the fans (141, 142, 143). The individual power supplied to the plurality of fans (141, 142, 143) can be individually controlled. The auxiliary power supply unit (180) can generate and supply auxiliary power using power input to the power conversion device (100). The auxiliary power supply unit (180) can include a flyback converter, etc.

[0034] The control unit (170) can PWM control the operation of the fan (140). The control unit (170) can include one or more processors and memories, and the processor can execute a PWM control command stored in the memory. The power supply unit (160) supplies power to the fan (140), and the control unit (170) can control the on / off operation of the fan (140) by applying a PWM signal to the fan (140). PWM (Pulse Width Modulation) control is a control method that variably controls the duty time, which is the on time, and can adjust the speed, time, torque, power, etc., of the fan (140) by increasing or decreasing the duty time, which is the on time in one cycle.

[0035] The control unit (170) can individually perform PWM control on multiple fans (141, 142, 143). Efficient control can be achieved by individually performing PWM control on multiple fans (141, 142, 143) depending on the environment or conditions.

[0036] Here, the control unit (170) can perform PWM control on the fans (141, 142, 143) using the temperature inside the housing (110). To this end, the power conversion device (100) according to the embodiment of the present invention can include a temperature measuring element (150).

[0037] The temperature measuring element (150) may include a plurality of temperature measuring elements. The plurality of temperature measuring elements (151, 152, 153) may measure the temperature of a plurality of temperature measuring points (130) inside the housing (110) corresponding to the mounting positions of the plurality of fans (141, 142, 143), respectively. The plurality of fans (141, 142, 143) may have different paths or positions in which the incoming air flows inside the housing (110), and positions where the temperature is measured corresponding to the positions of the plurality of fans (141, 142, 143) are set as temperature measuring points (131, 132, 133), and the temperature measuring elements (151, 152, 153) are placed at the corresponding positions to measure the temperature. The temperature measurement points (131, 132, 133) may be heat generating elements arranged at corresponding locations, and the temperature measurement elements (151, 152, 153) may measure the temperature of the corresponding heat generating elements. The plurality of temperature measurement points (131, 132, 133) may be arranged to be spaced apart from each other. The plurality of temperature measurement points (131, 132, 133) may be arranged to be spaced apart from each other at equal intervals, or the spacing may be close in areas where a lot of heat is generated inside the housing (110) and far apart in areas where little heat is generated. Alternatively, the plurality of temperature measurement points (131, 132, 133) may be arranged for each heat generating element that generates the most heat. The plurality of temperature measurement points (131, 132, 133) may each be set to have a corresponding fan (141, 142, 143). At this time, it may be set to correspond to a temperature measurement point (131, 132, 133) positioned on the path of the air flow formed by the fan (141, 142, 143), or it may be set to correspond to a temperature measurement point (131, 132, 133) positioned adjacent to the fan (141, 142, 143).

[0038] The temperature measuring element (150) may include a temperature sensor, a thermistor, and may include an NTC (Negative Temperature Coefficient of Resistance) or a PTC (Positive Temperature Coefficient of Resistance). An NTC is a resistor whose resistance value decreases when the temperature rises, and a PTC is a resistor whose resistance value increases when the temperature rises. The temperature measuring element (150) may measure the temperature of the temperature measuring point (130) using an NTC. The temperature measuring element (150) may measure the temperature of the temperature measuring point (130) at each cycle. The control unit (170) may set the measurement cycle differently depending on the temperature of the temperature measuring point (130) or the temperature difference with another temperature measuring point.

[0039] The control unit (170) can individually control multiple fans (141, 142, 143) by using the respective temperatures and differences between the respective temperatures of multiple temperature measurement points (131, 132, 133) measured by multiple temperature measurement elements (151, 152, 153).

[0040] A plurality of temperature measuring elements (151, 152, 153) measure the temperatures of a plurality of temperature measuring points (131, 132, 133) corresponding to a plurality of fans (141, 142, 143), and a control unit (170) compares the temperatures of the plurality of temperature measuring points (131, 132, 133) measured, and controls the plurality of fans (141, 142, 143) by using the temperatures of the plurality of temperature measuring points (131, 132, 133) and the temperature differences between the temperatures.

[0041] The control unit (170) can apply a PWM signal having the same duty to the plurality of fans (141, 142, 143) when the temperature difference between the plurality of temperature measurement points (131, 132, 133) is equal to or lower than a first value. When the temperature difference between the plurality of temperature measurement points (131, 132, 133) is equal to or lower than a preset first value, since heat generation is evenly generated between the temperature measurement points (131, 132, 133) spaced apart from each other throughout the housing (110), a PWM signal having the same duty can be applied to the plurality of fans (141, 142, 143) in order to lower the temperature of the entire housing (110). The duty of the PWM signal applied to the temperature measurement points (131, 132, 133) can be set according to the currently measured temperature. The higher the current temperature, the greater the duty can be applied to the PWM signal.

[0042] The control unit (170) may apply a PWM signal having a higher duty than other fans to the fan corresponding to the temperature measurement point having the highest temperature among the plurality of temperature measurement points (131, 132, 133) when the temperature difference between the plurality of temperature measurement points (131, 132, 133) is greater than the first value. When the temperature difference between the plurality of temperature measurement points (131, 132, 133) is greater than the first value, it means that a lot of heat is generated at a specific location. Therefore, in order to quickly lower the temperature at the location, a PWM signal having a higher duty than other fans may be applied to the fan corresponding to the temperature measurement point having the highest temperature among the plurality of temperature measurement points (131, 132, 133). The duty of the PWM signal applied to the temperature measurement point (131, 132, 133) may be set according to the currently measured temperature. The higher the current temperature, the greater the duty can be applied to the PWM signal.

[0043] At this time, the control unit (170) can apply a PWM signal having the maximum duty to the fan corresponding to the temperature measurement point having the highest temperature among the plurality of temperature measurement points (131, 132, 133). When the temperature of a specific temperature measurement point is higher than the temperatures of other temperature measurement points by a first value or more, the control unit (170) can quickly lower the temperature of the temperature measurement point by applying a PWM signal having the maximum duty to the fan corresponding to the temperature measurement point. When the control unit (170) applies a PWM signal having a different duty from that of other fans to at least one of the plurality of fans (141, 142, 143), the measurement cycle of the temperature measurement elements (151, 152, 153) can be set to be short. Thereafter, when the temperature difference between the plurality of temperature measurement points (131, 132, 133) becomes equal to or less than the first value, the same PWM signal can be applied to the plurality of fans (141, 142, 143), and the measurement cycle can also be reset to the previous measurement cycle.

[0044] The control unit (170) can apply different PWM signals according to the temperature of each temperature measurement point (131, 132, 133) when the difference between the temperatures of each of the plurality of temperature measurement points (131, 132, 133) is greater than the first value. Different PWM signals can be applied by setting the duty according to the temperature ratio.

[0045] The fault detection unit (144) can detect a fault in a plurality of fans (141). The fault detection unit (144) can detect whether the fan (140) is operating normally by detecting the position information of the blades mounted on the fan (141), and can detect whether there is a fault by detecting the voltage or current of the fan (141). The control unit (170) can control the fan (141) according to the signal of the fault detection unit (144). The fault detection unit (144) can transmit a DC fan fault detect signal to the control unit (170).

[0046] The control unit (170) can stop the operation of a fan among the plurality of fans (141, 142, 143) that has received a fault signal from the fault detection unit (144). As shown in FIG. 3, when the control unit (170) detects a fault in a specific fan among the plurality of fans (141, 142, 143) through a signal from the fault detection unit (144), the operation of the corresponding fan can be stopped. The control unit (170) can apply a PWM signal with a duty of 0 to the corresponding fan, or control the power supply unit (160) so that power is not supplied to the corresponding fan. The control unit (170) can operate a fan among the plurality of fans (141, 142, 143) that has not received a fault signal from the fault detection unit (144) according to the temperature measured by the plurality of temperature measurement elements (151, 152, 153). The fault detection unit (144) can operate other fans other than the fan in which a fault has been detected based on the temperature measured by the temperature measurement element (151, 152, 153).

[0047] The control unit (170) can increase the duty of the PWM signal for the fan that has stopped operating and the adjacent fan according to the fault signal of the fault detection unit (144). Through this, the temperature can be prevented from increasing at a location where the temperature may increase due to the stop of operation.

[0048] The power supply unit (160) may include a plurality of power conversion units (161, 162, 163) that are respectively connected to a plurality of fans (141, 142, 143) and supply individual power. In order to supply individual power to each of the plurality of fans (141, 142, 143), a plurality of power conversion units (161, 162, 163) may be included. The power conversion units (161, 162, 163) may include a buck converter, a boost converter, a buck-boost converter, etc.

[0049] In order to determine whether multiple power conversion units (161, 162, 163) are operating normally, a monitoring unit (164) that monitors information of the power conversion units (161, 162, 163) may be included. As shown in FIG. 3, the voltage, current, etc. of individual power supplied to each fan (141, 142, 143) from each power conversion unit (161, 162, 163) may be monitored, and the monitoring information may be supplied to the control unit (170). The control unit (170) may determine whether the power conversion units (161, 162, 163) are operating normally based on the monitoring information, and when operating normally, may operate the power conversion units (161, 162, 163) to supply power to each fan (141, 142, 143). At this time, the control unit (170) can apply an enable signal to the power conversion unit (161, 162, 163).

[0050] The control unit (170) may be an MCU as shown in FIG. 5, and the fan buck IC, which is the power supply unit (160), may convert the output of the auxiliary power unit (180) into individual power, which is a fan DC power, and supply it to a plurality of fans (141, 142, 143), which are DC fans. The plurality of fans (141, 142, 143) may be formed on one surface of the housing (110), as shown in FIG. 6. The housing (110) may include an AC-DC rectifier (121), which is a power conversion element (120), and an insulated DC-DC converter (122), and a plurality of temperature measurement points (131, 132, 133) for measuring the temperature used to control the fans (141, 142, 143) may be arranged to correspond to the positions of each fan (141, 142, 143).

[0051] The control unit (170) can receive a monitoring signal (165) from the fan buck IC, which is the power supply unit (160), and transmit an enable signal (173). A circuit that supplies individual power to a plurality of fans (141, 142, 143) is configured so that when a failure such as a power line defect occurs in at least one fan among the plurality of fans (141, 142, 143), the control unit (170) does not apply an enable signal to only the power line for the corresponding fan, thereby cutting off the power to only the corresponding fan. In this way, when an individual failure occurs or is diagnosed, the corresponding fan can be individually cut off to operate at maximum with only the other two fans, thereby demonstrating performance up to the protection temperature of the components.

[0052] The control unit (170) can supply a PWM signal (171, 172) to each fan (141, 142, 143). In addition, the control unit (170) can receive a fault signal from a fault detection unit (144) (DC fan fault detect) and control the fan accordingly. When a PWM signal is applied but the fan does not operate, a fault signal is generated and transmitted to the control unit (170) to check whether the corresponding fan is faulty. In addition to the fault diagnosis signal, a monitoring unit (164) for the power supply unit (160) is configured so that not only the fan itself can be fault-diagnosed, but also the circuit that supplies power to each fan can be individually driven and controlled by the control unit (170) through fault diagnosis.

[0053] The control unit (170) can control the rotation speed of the fans (141, 142, 143) by controlling the pulse width (Duty cycle, %) of the signal applied to the fans (141, 142, 143). Since the heat generation points and parts of the electrical components, such as the power conversion element (120) in the power conversion device (100), which is a power module, may all be different, if the duty of multiple fans (141, 142, 143) is controlled to be the same, the power consumed by the fans may increase, which may cause loss, i.e., performance degradation. For example, if heat generation occurs only at the temperature measurement point (151) of FIG. 6 and only heat generation that does not require driving the fan occurs at the temperature measurement point (153), the temperature of the temperature measurement point (151) can be lowered by driving only the fan (141) or the fan (141) and the fan (142) corresponding to the temperature measurement point (151).

[0054] The process of efficiently controlling the fans (141, 142, 143) in the control unit (170) can be performed as shown in Fig. 7. First, the power of the fans (141, 142, 143) is checked, and if the power of the fans (141, 142, 143) is normal, then the standby is performed and the temperature measuring elements (151, 152, 153) measure the temperature of the temperature measuring points (131, 132, 133). Here, the temperature measuring elements (151, 152, 153) can be NTC, and the respective measured temperatures (NTC1, 2, 3) are compared. As a result of the comparison, if the temperature difference between the temperatures (NTC1, 2, 3) is less than the first value of 5 degrees and the temperatures (NTC1, 2, 3) are all less than 50 degrees, a PWM signal with a duty of 50% can be applied to the fans (141, 142, 143), and if the temperatures (NTC1, 2, 3) are all 50 or higher, a PWM signal with a duty of 70% can be applied to the fans (141, 142, 143).

[0055] As a result of the comparison, if the temperature difference between the temperatures (NTC1,2,3) is greater than the first value of 5 degrees, and the temperatures (NTC1,2,3) are all less than 50 degrees, a PWM signal having a maximum duty of 100% can be applied to the fan corresponding to the temperature measurement point with the highest temperature, and a PWM signal having a duty of 50% can be applied to other fans.

[0056] When the temperature difference between the temperatures (NTC1, 2, 3) is greater than the first value of 5 degrees, and the temperatures (NTC1, 2, 3) are all 50 degrees or more and less than 70 degrees, a PWM signal having a maximum duty of 100% can be applied to the fan corresponding to the temperature measurement point with the highest temperature, and a PWM signal having a duty of 70% can be applied to other fans.

[0057] As described above, by implementing an individual power supply circuit and a fault diagnosis circuit of a cooling PWM DC FAN applied to an EV charger module, i.e., a power conversion device (100) which is an electric vehicle charging device, and individually controlling the fan according to temperature, the performance of the power module can be improved.

[0058] Those skilled in the art will appreciate that the present invention can be implemented in modified forms without departing from the essential characteristics of the above-described description. Therefore, the disclosed methods should be considered illustrative rather than restrictive. The scope of the present invention is set forth in the claims, not the foregoing description, and all differences within the scope equivalent thereto should be construed as being encompassed by the present invention.

Claims

1. A housing that accommodates a plurality of elements that perform power conversion; A plurality of fans mounted in the above housing; A plurality of temperature measuring elements each measuring the temperature of a plurality of temperature measuring points inside the housing, each corresponding to the mounting positions of the plurality of fans; A power supply unit that supplies individual power to the plurality of fans; and A power conversion device including a control unit that PWM controls the plurality of fans.

2. In paragraph 1, The above control unit, A power conversion device that individually controls the plurality of fans by using the respective temperatures of the plurality of temperature measurement points measured by the plurality of temperature measurement elements and the differences between the respective temperatures.

3. In paragraph 2, The above control unit, A power conversion device that applies a PWM signal having the same duty to the plurality of fans when the difference between each temperature of the plurality of temperature measurement points is less than or equal to a first value.

4. In paragraph 2, The above control unit, If the difference between the temperatures of the above multiple temperature measurement points is greater than the first value, A power conversion device that applies a PWM signal having a higher duty than other fans to a fan corresponding to a temperature measurement point having the highest temperature among the above-mentioned multiple temperature measurement points.

5. In paragraph 3, The above control unit, A power conversion device that applies a PWM signal having a maximum duty to a fan corresponding to a temperature measurement point having the highest temperature among the above-mentioned plurality of temperature measurement points.

6. In paragraph 1, Including a failure detection unit that detects failure of the above plurality of fans, The above control unit, A power conversion device that controls the plurality of fans according to a signal from the above fault detection unit.

7. In paragraph 6, The above control unit, Stop the operation of a fan that has received a fault signal from the fault detection unit among the above multiple fans, A power conversion device that operates a fan among the plurality of fans that does not receive a fault signal from the fault detection unit according to the temperature measured by the plurality of temperature measuring devices.

8. In paragraph 1, The above power supply unit, It includes a plurality of power conversion units that are respectively connected to the plurality of fans and supply the individual power, A power conversion device including a monitoring unit that monitors information of the plurality of power conversion units.

9. In paragraph 1, Including an auxiliary power unit that supplies power to the above control unit, The above power supply unit, A power conversion device that converts power supplied from the auxiliary power source and supplies it to each of the plurality of fans.

10. In paragraph 1, A power conversion device wherein the above plurality of temperature measuring elements include NTC elements or PTC elements.

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