Self-adaptive capacitor for reducing internal thermal stress concentration

Abstract

The invention discloses a self-adaptive capacitor capable of reducing internal thermal stress concentration, and belongs to the technical field of capacitors, the self-adaptive capacitor comprises a shell and a core arranged in the shell, an upper busbar is arranged above the core, and a lower busbar is arranged below the core; a self-adaptive device is arranged between the upper end of each core and the upper busbar, the self-adaptive device comprises a temperature sensor and an action mechanism, the temperature sensor is used for detecting the temperature of the corresponding core, the action mechanism has two states, and in the first state, the corresponding core is connected with the upper busbar through the action mechanism; and in the second state, the corresponding core is disconnected from the upper busbar. On the basis of ensuring the high-frequency current supply capability, in order to avoid the phenomenon of thermal stress concentration in the capacitor, the temperature sensor is used for detecting the temperature condition of each core, and the core at the lowest temperature is connected and the working core at the highest temperature is disconnected, so that the thermal stress is dispersed, the temperature uniformity in the capacitor is improved, and the service life of the capacitor is prolonged.

Description

Technical Field

[0001] The present invention mainly relates to the technical field of capacitors, and in particular to an adaptive capacitor capable of reducing internal thermal stress concentration. Background Art

[0002] Metallized film capacitors play an important role in new energy vehicle controllers. DC bus capacitors are used to smooth the bus voltage, reduce the inductance parameters of the line from the IGBT end of the motor controller to the power battery end, weaken the peak voltage of the bus, absorb the high pulse current at the bus end of the motor controller, and prevent the overcharging of the bus end voltage and the influence of the transient voltage on the motor controller. Under the development trend of high temperature and high density of motor controllers, DC bus capacitors are also developing in the direction of high temperature resistance and high volume ratio. There are some adaptive adjustment devices for existing metallized film capacitors for electric vehicles. Based on parameters such as voltage, current, and temperature, the capacitance of the capacitor is adjusted under different working conditions to ensure the capacitor's ability to provide high-frequency current.

[0003] Existing adaptive adjustment devices for film capacitors used in automotive motor controllers only adjust the capacitance of the capacitor according to actual working conditions in order to ensure the capacitor's ability to provide high-frequency current. This fails to fully consider the phenomenon of thermal stress concentration in the capacitor, which can easily cause damage to the capacitor and reduce its lifespan. Summary of the invention

[0004] The technical solution of the present invention aims at the technical problem that the existing technical solutions are too single, and provides a solution that is significantly different from the existing technology. It mainly provides an adaptive capacitor that reduces internal thermal stress concentration, so as to solve the technical problem of thermal stress concentration of the existing adaptive capacitance adjustment capacitor proposed in the above background technology.

[0005] The technical solution adopted by the present invention to solve the above technical problems is: An adaptive capacitor for reducing internal thermal stress concentration comprises a shell and a core arranged in the shell, an upper busbar is arranged above the core, and a lower busbar is arranged below the core; an adaptive device is arranged between the upper end of each core and the upper busbar, the adaptive device comprises a temperature sensor and an action mechanism, the temperature sensor is used to detect the temperature of the corresponding core, and the action mechanism has two states, in the first state, the corresponding core is connected to the upper busbar through the action mechanism; in the second state, the corresponding core is disconnected from the upper busbar.

[0006] Furthermore, the actuating mechanism comprises two contact terminals arranged opposite to each other and a driving mechanism for driving the two contact terminals to move closer to or farther from each other, and the two contact terminals are respectively located on the sides where the core and the upper busbar are located.

[0007] Furthermore, the driving mechanism includes a gear and two meshing racks located on opposite sides of the gear. A servo motor for driving the gear to rotate is connected to the center of the gear. The gear and the rack are both located between two contact terminals, and the two racks are connected to the two contact terminals in a one-to-one correspondence.

[0008] Furthermore, the adaptive device includes a shell, the temperature sensor, contact terminals and drive mechanism are all located inside the shell, the upper and lower ends of the shell are respectively connected to the busbar and the core, and the temperature sensor and the driver of the drive mechanism are respectively electrically connected to the controller.

[0009] Furthermore, the adaptive device also includes a current sensor arranged in the shell, and the current sensor is electrically connected to the controller.

[0010] Furthermore, the driving mechanism comprises a servo motor, and the servo motor is fixedly connected to the inner wall of the shell through feet.

[0011] Furthermore, one end of the lower busbar extends above the upper busbar, there is an overlapping portion between the lower busbar and the upper busbar, and there is a gap between the lower busbar and the upper busbar.

[0012] Compared with the prior art, the present invention has the following beneficial effects: The present invention is provided with an adaptive device which is arranged one by one in correspondence with the cores. By detecting the temperature of each core through a temperature sensor, an over-temperature core can be discovered in time, and the corresponding core can be disconnected from the upper busbar through an action mechanism. At the same time, the low-temperature core can be connected to the upper busbar through the action mechanism, thereby dispersing thermal stress, improving the temperature uniformity inside the capacitor, avoiding the concentration of thermal stress inside the capacitor, and extending the service life of the capacitor.

[0013] The present invention can connect or disconnect the corresponding core through the action mechanism of the adaptive device. When the capacitor is working, the capacitance value can be changed by adjusting the number of connected cores to ensure the supply of high-frequency current to the capacitor, that is, to achieve adaptive adjustment of the capacitor; while ensuring the supply of high-frequency current, the adaptive device can also avoid the concentration of thermal stress inside the capacitor. Therefore, the present invention can achieve multiple functions through a simple structure.

[0014] The present invention will be explained in detail below with reference to the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the three-dimensional structure of the present invention; Figure 2 A top view of the core and the lower busbar in the present invention; Figure 3 It is a side view of the core, the upper busbar and the lower busbar in the present invention; Figure 4 It is a schematic diagram of the structure of the adaptive device in the present invention; Figure 5 It is the workflow diagram of the present invention.

[0016] Figure numerals: 1. core; 2. lower busbar; 3. housing; 4. upper busbar; 5. adaptive device; 51. rack; 52. gear; 53. contact terminal; 54. servo motor; 55. temperature sensor; 56. current sensor. DETAILED DESCRIPTION

[0017] To facilitate understanding of the present invention, the present invention will be described more comprehensively below with reference to the relevant drawings. Several embodiments of the present invention are given in the drawings, but the present invention can be implemented in different forms and is not limited to the embodiments described in the text. On the contrary, these embodiments are provided to make the content disclosed in the present invention more thorough and comprehensive.

[0018] It should be noted that when an element is referred to as being "fixed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used in this article are for illustrative purposes only.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly connected by technicians in the technical field of the present invention. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used in this article includes any and all combinations of one or more related listed items.

[0020] Example 1: Please refer to the attached Figure 1-4 , an adaptive capacitor for reducing internal thermal stress concentration, comprising a core 1, a lower busbar 2, a shell 3, an upper busbar 4, an adaptive device 5 and other components.

[0021] The cores 1 are neatly arranged inside the shell 3; The main body of the lower busbar 2 is located at the bottom of the core 1, and the lower end surface of the core 1 is fixed to the lower busbar 2 by welding; one side of the lower busbar 2 extends longitudinally along the inner arm of the shell 3 to the top of the core 1, and extends a part transversely; The housing 3 is a rectangular box structure; the internal spaces are filled with epoxy resin (not shown in the figure); The upper busbar 4 is located above the core 1 and below the extended end of the lower busbar 2. The upper and lower busbars partially overlap, and there is a gap between the lower busbar 2 and the upper busbar 4, which can reduce the stray inductance. The adaptive device 5 is arranged in one-to-one correspondence with the core 1 and is arranged between the core 1 and the upper busbar 4; and is used to connect or disconnect the corresponding core 1.

[0022] Specifically, the adaptive device 5 includes a shell, a temperature sensor 55, two contact terminals 53 and a driving mechanism. The shell of the adaptive device 5 is fixed by epoxy resin, and the upper and lower ends of the shell are respectively connected to the busbar 4 and the core 1; the temperature sensor 55, the two contact terminals 53 and the driving mechanism are all located inside the shell, and the two contact terminals 53 are respectively located on the sides where the upper and lower ends of the shell are located; the driving mechanism is used to drive the two contact terminals 53 to move closer to or away from each other; the driving mechanism includes a servo motor 54, the servo motor 54 is fixedly connected to the inner wall of the shell through a ground pin (not shown in the figure), and the temperature sensor 55 and the servo motor 54 are both electrically connected to the controller.

[0023] When in use, the temperature of each core 1 is detected by the temperature sensor 55 and transmitted to the controller. The controller compares the temperature value with the preset threshold value. When an over-temperature condition is found, the corresponding servo motor 54 is controlled to drive the two contact terminals 53 to move closer to each other through the driving mechanism, that is, the upper busbar 4 and the corresponding core 1 are disconnected, so that the corresponding core 1 does not participate in the work; at the same time, the controller controls the adaptive device 5 corresponding to the core 1 (low temperature) that did not participate in the work before, and connects the core 1 to the upper busbar 4 to participate in the work. In this way, the thermal stress is dispersed, the temperature uniformity inside the capacitor is improved, and the thermal stress concentration phenomenon inside the capacitor is avoided, so as to extend the service life of the capacitor.

[0024] Embodiment 2: This embodiment differs from Embodiment 1 in that: In this embodiment, if Figure 4 As shown, the driving mechanism includes a gear 52 and two racks 51 respectively meshing on two opposite sides of the gear 52. A servo motor 54 for driving the gear 52 to rotate is connected to the center of the gear 52. The gear 52 and the rack 51 are both located between two contact terminals 53, and the two racks 51 are connected to the two contact terminals 53 in a one-to-one correspondence.

[0025] When the core 1 needs to be connected, the servo motor 54 drives the gear 52 to rotate, driving the two racks 51 to move in opposite directions, and driving the two contact terminals 53 to move away from each other, so that the two contact terminals 53 respectively contact the upper and lower ends of the shell, thereby realizing the connection between the corresponding core 1 and the upper busbar 4; when the core 1 needs to be disconnected, the servo motor 54 drives the gear 52 to rotate in the opposite direction, driving the two racks 51 to move in opposite directions, and driving the two contact terminals 53 to move closer to each other, so that the two contact terminals 53 respectively detach from the upper and lower ends of the shell, thereby realizing the disconnection of the corresponding core 1.

[0026] Regarding the control stroke of the servo motor 54, first determine the distance required when the upper busbar 4 is connected to the core 1, and set the movement angle of the gear 52 according to the movement distance of the rack 51. The servo motor 54 receives the set pulse signal and rotates a fixed angle to achieve precise control.

[0027] The rest is the same as the first embodiment.

[0028] Embodiment 3: This embodiment differs from Embodiment 2 in that: In this embodiment, if Figure 4 As shown, the adaptive device 5 also includes a current sensor 56 disposed in the housing, and the current sensor 56 is electrically connected to the controller. The current sensor 56 is used to monitor the high-frequency ripple current output of the core 1, thereby determining the capacitance value provided by the capacitor and selecting the number of connected cores 1. Whether the current sensor 56 can detect the current output is used to determine whether the corresponding core 1 is in a working state.

[0029] like Figure 5 As shown, the working process of the above adaptive capacitor is: S1, the capacitor works, and its current sensor 56 detects the current of each core 1 and transmits it to the controller; S2. The controller monitors the high-frequency current supply of the capacitor and determines whether the high-frequency current supply can be guaranteed. If the high-frequency current supply cannot be guaranteed, the controller controls the servo motor 54 to increase the number of connected cores 1 to achieve a change in capacitance and ensure the supply of high-frequency current of the capacitor (the capacitor will resonate in the discharge circuit. At the resonance point, the impedance of the discharge circuit is the smallest and the ability to provide high-frequency current is the strongest. A capacitor value that is too small will lead to thermal stress concentration, and a capacitor value that is too large will lead to a decrease in the resonant frequency. The resonant frequency is a function of the capacitance. Each core 1 has a rated capacitance. The resonant frequency is adjusted to a point close to the resonance point by adjusting the number of cores 1 involved in the work); S3. Under the condition of ensuring the supply of high-frequency current, each temperature sensor 55 detects the temperature of each core 1 and transmits it to the controller; S4. The controller determines whether the temperature of the working core 1 exceeds a preset threshold value. Once an over-temperature condition occurs, it determines whether there are any unconnected cores 1. If there are any unconnected cores 1, the servo motor 54 adjusts its working state according to the temperature of each core 1, connects the core 1 with the lowest temperature min{T1, T2, ..., Tn}, and disconnects the working core 1 with the highest temperature max{T1, T2, ..., Tn}; in order to ensure that the capacitance value is constant before and after switching, the number of disconnected cores 1 is consistent with the number of connected cores 1.

[0030] The rest is the same as the second embodiment.

[0031] Embodiment 4: This embodiment differs from Embodiment 3 in that: In this embodiment, if Figure 1 As shown, the upper busbar 4 includes a long strip portion overlapping with the lower busbar 2, and a short strip portion arranged at equal intervals extends from one side of the long strip portion, and the short strip portion corresponds to the number of columns of the core 1, and a notch is provided on both sides of the short strip portion. By changing the shape of the busbar, the stray inductance in the capacitor can be reduced.

[0032] The rest is the same as in the third embodiment.

[0033] In summary, the present invention realizes adaptive adjustment of the capacitance of the capacitor by changing the number of cores connected to the circuit, thereby ensuring its high-frequency current supply capacity. On this basis, a temperature sensor is used to detect the temperature of each core, and by connecting the core at the lowest temperature and disconnecting the working core at the highest temperature, the thermal stress is dispersed, the temperature uniformity inside the capacitor is improved, and the service life of the capacitor is extended.

[0034] The above is an exemplary description of the present invention in combination with the accompanying drawings. It is obvious that the specific implementation of the present invention is not limited to the above-mentioned method. As long as such non-substantial improvements are made by adopting the method concept and technical solution of the present invention, or the concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. An adaptive capacitor for reducing internal thermal stress concentration, comprising a housing (3) and a core (1) disposed in the housing (3), an upper busbar (4) being disposed above the core (1), and a lower busbar (2) being disposed below the core (1); characterized in that: An adaptive device (5) is provided between the upper end of each core (1) and the upper busbar (4). The adaptive device (5) comprises a temperature sensor (55) and an action mechanism. The temperature sensor (55) is used to detect the temperature of the corresponding core (1). The action mechanism has two states. In the first state, the corresponding core (1) is connected to the upper busbar (4) through the action mechanism. In the second state, the corresponding core (1) is disconnected from the upper busbar (4).

2. The adaptive capacitor for reducing internal thermal stress concentration according to claim 1, characterized in that: The action mechanism comprises two contact terminals (53) arranged opposite to each other and a driving mechanism for driving the two contact terminals (53) to move closer to or farther from each other, and the two contact terminals (53) are respectively located on the sides where the core (1) and the upper busbar (4) are located.

3. The adaptive capacitor for reducing internal thermal stress concentration according to claim 2, characterized in that: The driving mechanism comprises a gear (52) and two racks (51) respectively meshingly located on two opposite sides of the gear (52); a servo motor (54) for driving the gear (52) to rotate is connected at the center of the gear (52); the gear (52) and the rack (51) are both located between two contact terminals (53), and the two racks (51) are connected to the two contact terminals (53) in a one-to-one correspondence.

4. The adaptive capacitor for reducing internal thermal stress concentration according to claim 2, characterized in that: The adaptive device (5) comprises a housing, the temperature sensor (55), the contact terminal (53) and the drive mechanism are all located inside the housing, the upper and lower ends of the housing are respectively connected to the busbar (4) and the core (1), and the temperature sensor (55) and the driver of the drive mechanism are respectively electrically connected to the controller.

5. The adaptive capacitor for reducing internal thermal stress concentration according to claim 4, characterized in that: The adaptive device (5) further comprises a current sensor (56) arranged in the housing, and the current sensor (56) is electrically connected to the controller.

6. The adaptive capacitor for reducing internal thermal stress concentration according to claim 4, characterized in that: The driving mechanism comprises a servo motor (54), and the servo motor (54) is fixedly connected to the inner wall of the housing via a foot.

7. An adaptive capacitor for reducing internal thermal stress concentration according to any one of claims 1 to 6, characterized in that: One end of the lower busbar (2) extends above the upper busbar (4), the lower busbar (2) and the upper busbar (4) have overlapping portions, and a gap exists between the lower busbar (2) and the upper busbar (4).

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