English:
[0002] Some circuit interruption devices, which include circuit breakers, ON/OFF switches and the like have employed shape memory alloy (SMA) elements as a thermal circuit breaker or as a replacement of a solenoid in these devices. It can be difficult to quickly and accurately heat the SMA element at various operating temperature requirements. At a lower temperature, more energy is needed to raise the temperature of the SMA element to achieve a change in shape of the SMA element, but at a higher temperature less energy is required to avoid permanent damage to the SMA element.
[0004] An example of a method of operating an electrically controlled switching device includes delivering an electrical pulse to an SMA element, and adjusting the electrical pulse being delivered to the SMA element. The SMA element transforms between a first shape and a different second shape when heated to a transformation temperature. The electrical pulse is delivered to the SMA element to heat the SMA element to a desired temperature less than through transformation temperature. The electrical pulse being delivered to the SMA element is then adjusted to maintain a detected temperature of the SMA element at about the desired temperature.
[0005] Another example of an electrically controlled switching device includes a support, a first contact coupled to the support, a second contact coupled to the support, an SMA element operably connected with the second contact, and a controller. The second contact is moveable toward and away from the first contact. The SMA element is configured to transform between a first shape and a different second shape responsive to an electrical pulse heating the SMA element to a transformation temperature. The controller is configured to control the electrical pulse at least between a pre-heating state and a transformation state. In the preheating state, the controller controls the electrical pulse being delivered to the SMA element so as to heat the SMA element to a first desired temperature, which is less than the transformation temperature. In the transformation state, the controller controls the electrical pulse being delivered to the SMA element so as to heat the SMA element to a second desired temperature, which is equal to or greater than the transformation temperature.
[0006] FIG. 1 is a schematic sectional view of an electrically controlled switching device having contacts in an OFF position.
[0007] FIG. 2 is a schematic sectional view of the electrically controlled switching device with the contacts in an ON position.
[0008] An example of an electrically controlled switching device 10 is depicted in FIGS. 1 and 2. In general, the electrically controlled switching device 10 includes a support 12, a set of separable contacts 14 including a first contact 16 and a second contact 18, an SMA element 20, a sensor 22, and a controller 24. The first contact 16, which can also be referred to as a fixed contact in that the position of the first contact is fixed with respect to the support 12, can connect with a line conductor 28. The second contact 18, which can also be referred to as a moveable contact in that it is moveable with respect to the support 12, can connect with a load conductor 30. The electrically controlled switching device 10 is operable to move the set of contacts 14 between an open condition, which is shown in FIG. 1 , and a closed condition, which is shown in FIG. 2. The electrically controlled switching device 10 is operable in at least two states: an ON state, which is shown in FIG. 2, where the first contact 16 is in contact with the second contact 18, which causes the line conductor 28 and the load conductor 30 to be electrically connected together, and an OFF state, which is shown in FIG. 1 , where the first contact 16 is spaced from the second contact 18 so that the line conductor 28 is not electrically connected with the load conductor 30.
[0009] The support 12 can be an electrically nonconductive housing for the switching device 10. The first contact 16 is coupled to the support 12 and the second contact 18 is also coupled to the support 12, which is schematically depicted in FIGS. 1 and 2.
[0010] The SMA element 20 connects at a first end 34 to a heat sink 36, which is connected with the support 12, and at a second end 38 with a contact carrier 42 that is coupled with the second contact 18. The SMA element 20 can be made of a Single Crystal Shape Memory Alloy (SCSMA) that can be formed from a metallic alloy largely including copper-aluminum-nickel (Cu-AI-Ni) or other appropriate alloy. The SMA element 20 can also be formed from other known alloys that can change shape when heated as described below. An SCSMA has various advantages over a conventional SMA, and thus the SMA element 20 may desirably be formed of an SCSMA. Advantages of an SCSMA include significantly greater strain recovery that is generally 100% repeatable and complete. This is especially desirable when the electrically controlled switching device 10 is to operate between two states, e.g., an ON state and an OFF state.
[0011] As is generally understood in the art, an SMA material such as a conventional SMA or SCSMA, is typically formed to have an original shape. The SMA material can thereafter be deformed into a deformed shape while remaining at a temperature that is less than the transition temperature of the SMA material. Upon heating the SMA material to its transformation temperature, the SMA material transforms from its deformed shape back into its original shape. Upon cooling of the SMA material below its transformation temperature, the SMA material may return to the deformed shape.
[0012] With reference back to the illustrated embodiment, the SMA element 20 is configured to transform between a first shape and a different second shape responsive to heating the SMA element to a transformation temperature. More particularly, the SMA element 20 is configured to transform between a first shape and a different second shape responsive to an electrical pulse heating the SMA element 20 to the transformation temperature. In the depicted embodiment, the SMA element 20 is an elongated wire whose length changes when changing between the first shape and the second shape. The first shape is relatively shorter than the second shape. When the electrical pulse is applied to the SMA element 20 so as to heat the SMA element above the transformation temperature, the SMA element 20 shortens from its relatively longer first shape to its relatively shorter second shape. Such a shrinking or reduction in length of the SMA element 20 causes the carrier 42 to move, which results in the second contact 18 moving with respect to the first contact 16. When the SMA element 20 is heated to the transformation temperature by the electrical pulse applied to the SMA element 20, the length of the SMA element 20 shrinks a change in length sufficient to move the carrier 42 from a position shown in FIG. 1 to a position shown in FIG. 2.
[0013] The heat sink 36 in the illustrated embodiment is formed from aluminum or another appropriate thermally conductive material. The heat sink 36 is configured to rapidly cool the SMA element 20 to a temperature below the transformation temperature after the application of the electrical pulse that was applied to the SMA element 20 to raise the SMA element 20 above the transformation temperature has been stopped. The heat sink 36 operates in a known manner by removing heat from the SMA element 20, for example by dumping the heat into ambient.
[0014] As stated above, a second end 38 of the SMA element 20 is connected with the carrier 42, which results in the SMA element 20 being operably connected with the second contact 18 through the carrier 42. A spring 50 can be provided to bias the carrier 42 toward a first position shown in FIG. 1 placing the contacts 14 in the open position. The spring 50 acts against the support 12 to bias the carrier 42 toward the position shown in FIG. 1 . When the SMA element 20 is heated above the transformation temperature, the SMA element 20 shrinks from the first shape shown in FIG. 1 to the second shape shown in FIG. 2, which moves the carrier 42 upward (per the orientation shown in FIG. 2) overcoming the biasing force of the spring 50. This movement of the carrier 42 results in movement of the second contact 18 toward the first contact 16, which places the contacts in the closed position shown in FIG. 2.
[0015] The sensor 22 is positioned on or adjacent the SMA element 20 and is configured to detect the temperature of the SMA element 20. The sensor 22 can be placed in contact with the SMA element 20 and/or placed in contact with the heat sink 36 to measure or detect the temperature of the SMA element 20. The sensor 22 can also be spaced from the SMA element 20 and use known technologies, e.g., IR technologies, to measure or detect the temperature of the SMA element 20.
[0017] The controller 24 can control the electrical pulse being delivered to the SMA element 20 between a pre-heating state and a transformation state. In the electrically controlled switching device 10 in the illustrated embodiment, the controller 24 can control the electrical pulse being delivered to the SMA element 20 so as to pre-heat the SMA element to a desired temperature that is less than the transformation temperature. As such, in this pre-heating state, the SMA element 20 remains in the first shape shown in FIG. 1 , but the SMA element 20 may have a temperature well above ambient, for example. For example, in the pre-heating state the temperature of the SMA element 20 may be about 10 degrees to about 20 degrees C less than the transformation temperature so that when it is desired to change the shape of the SMA element 20, the SMA element 20 can be more quickly transformed from the first shape to the second shape since the temperature differential between the temperature of the SMA element 20 and the transformation temperature is smaller as compared to keeping the SMA 20 element at ambient temperature.
[0018] As stated above, the controller 24 receives signals from the sensor 22 indicative of the detected temperature of the SMA element 20. The controller 24 is configured to control the electrical pulse while allowing for the delivery of the electrical pulse to the SMA element 20 such that the detected temperature is less than the transformation temperature, but typically greater than ambient temperature. The controller 24 is configured to compare the detected temperature, which is detected by the sensor 22, to the desired temperature and to adjust the electrical pulse based on a comparison between the detected temperature and the desired temperature. For example, the desired temperature can be a first desired temperature which is about 10 degrees to about 20 degrees C less than the transformation temperature in the pre-heating state. As such, the controller 24 can compare the detected temperature, which is indicative of the actual temperature of the SMA element 20, and compare this to the first desired temperature, which can be slightly less than the transformation temperature. If the detected temperature is not within the range of about 10 degrees to about 20 degrees C less than the transformation temperature, then the controller 24 can adjust the signal to deliver more power to the SMA element 20 to increase the temperature of the SMA element 20. The controller 24 is also configured to control the electrical pulse while allowing for the delivery of the electrical pulse to the SMA element 20 so as to heat the SMA element 20 to a second desired temperature, which is greater than or equal to the transformation temperature. The amount of power being delivered to the SMA element 20 during this transformation state is enough to heat the SMA element 20 to or above the transformation temperature so that the SMA element 20 transforms from the first shape to the different second shape. As explained above, this can result in a shortening of the SMA element 20, which moves the carrier 42 from the position shown in FIG. 1 to the position shown in FIG. 2, so as to close the contacts 14 placing the electrically controlled switching device in the ON state. By providing signals indicative of the temperature of the SMA element 20 from the sensor 22 to the controller 24, the controller 24 can adjust the electrical pulse to compensate for the difference (or error) between the desired temperature and the detected (or actual) temperature of the SMA element 20.
[0019] A method of operating an electrically controlled switching device, such as the switching device 10 depicted in FIGS. 1 and 2, includes delivering an electrical pulse to an SMA element, such as the SMA element 20, to heat the SMA element to a desired temperature less than the transformation temperature. It is during this stage that a controller, e.g., the controller 24, controls the electrical pulse so that the electrical pulse is in a pre-heating state to heat the SMA element 20 to a first desired temperature, which is less than the transformation temperature. The method further includes adjusting the electrical pulse being delivered to the SMA element 20 to maintain a detected temperature of the SMA element 20 at about this desired temperature. As explained above, for example, the electrical pulse being delivered to the SMA element 20 can be adjusted so that the desired temperature is about 10 degrees to about 20 degrees C less than the transformation temperature. The controller 24 can be programmed to maintain the SMA element 20 within this desired temperature range and to accommodate for any error between the desired temperature and the detected temperature. This can allow for a faster transformation between the first shape and the second shape when it is desired to change the SMA element 20 from the first shape to the second shape.
[0020] The method further includes detecting the detected temperature of the SMA element 20 using the sensor, such as the sensor 22 depicted in FIGS. 1 and 2. The method further includes comparing the detected temperature, which can be detected by the sensor 22, to the desired temperature in a controller, such as the controller 24, which is in communication with the sensor. The electrically controlled switching device can operate between an ON state and an OFF state. The method can further include receiving a signal in the controller 24 to change an ON/OFF state of the electrically controlled switching device. The controller 24 can receive this change in state signal from outside of the electrically controlled switching device 10. The method further includes adjusting the electrical pulse being delivered to the SMA element 20 so as to heat the SMA element 20 to a second desired temperature which is greater than or equal to the transformation temperature, upon receiving a signal and the controller 24 to change an ON/OFF state of the electrically controlled switching device. In other words, when it is desired to change the position of the contacts 14 from what is shown in FIG. 1 to what is shown in FIG.2, a signal can be delivered to the controller 24, which can then adjust the electrical pulse being delivered to the SMA element 20. The method can further include receiving another signal in the controller 24 to change the ON/OFF state of the electrically controlled switching device 10. For example, with the contacts 14 shown in the position shown in FIG. 2, another signal can be received by the controller 24 to place the contacts in the open position. As such, the method can further include stopping delivery of the electrical pulse to the SMA element 20, which can allow for the transformation of the SMA element 20 from the second shape shown in FIG. 2 back to the first shape shown in FIG. 1 . Heat is dissipated from the SMA element 20 into the heat sink 36, which reduces the temperature of the SMA element 20, which allows for the SMA element 20 to move from the second shape (FIG. 2) back to the first shape shown in FIG. 1. As such, stopping the delivery of the electrical pulse to the SMA element 20 can further include stopping delivery of the electrical pulse until the SMA element 20 reaches a first desired temperature, which is about 10 degrees to about 20 degrees C less than the transformation temperature. While remaining in the state shown in FIG. 1 , the electrical pulse can be adjusted to the SMA element 20 to maintain the detected temperature of the SMA element 20 at about the first desired temperature, which is less than the transformation temperature.

中文:
[0002]包括电路断路器,开/关开关等的一些电路中断装置使用形状记忆合金(SMA)元件作为热电路断路器或作为这些装置中螺线管的替代物。在不同的工作温度要求下快速并准确地加热SMA元件可以是困难的。在一较低的温度下,需要更多的能量来提高SMA元件的温度,以实现SMA元件的形状的改变,但在一较高温度下,需要较少的能量以避免SMA元件的永久损坏。
[0004]操作一电控开关装置的方法的例子包括向一SMA元件传递一电脉冲,以及调整传递到该SMA元件的电脉冲。该SMA元件在一第一形状与加热到一转变温度的一不同的第二形状之间转变。该电脉冲传递到该SMA元件,以将该SMA元件加热到一低于通过转变温度的所期望的温度。传递到该SMA元件的该电脉冲随后被调整,以将该SMA元件的一探测温度保持在大约该所期望的温度。
[0005]电控开关装置的另一个例子包括一支撑件、连接到该支撑件的第一接触器、连接到该支撑件的第二接触器、可操作地与所述第二接触器相连的SMA元件,以及一控制器。该第二接触器可朝向该第一接触器移动并可远离该第一接触器移动。该SMA元件设置为在一第一形状与一响应于一将该SMA元件加热到一转变温度的电脉冲的不同的第二形状之间转变。该控制器设置为至少在一预加热状态与一转变状态之间控制该电脉冲。在该预加热状态,该控制器控制传递到该SMA元件,以将该SMA元件加热到一低于转变温度的第一期望温度的电脉冲。在该转变状态,所述控制器控制传递到该SMA元件,以将该SMA元件加热到一等于或大于转变温度的第二期望温度的电脉冲。
[0006]图1是在一关闭位置的具有接触器的电控开关装置的示意性截面图。
[0007]图2是在一打开位置的具有接触器的电控开关装置的示意性截面图。
[0008]电控开关装置10的一个例子显示在图1和图2中。通常,电控开关装置10包括一支撑件12、包括第一接触器16和第二接触器18的一组可分离的接触器14、一SMA元件20、一传感器22和一控制器24。该第一接触器16,也称作固定接触器,其位置相对于支撑件12固定,并可与一线导体28相连。该第二接触器18,也称作可移动接触器,其可相对于支撑件12移动,并可与一负载导体30相连。电控开关装置10可操作为将该组接触器14在图1中所示的一打开状态与在图2中所示的一关闭状态之间移动。该电控开关装置10可在至少两个状态中工作:一打开状态,其显示于图2中,其中第一接触器16与第二接触器18相接触,它使线导体28与负载导体30电连接到一起,以及一关闭状态,其显示于图1中,其中第一接触器16与第二接触器18间隔开,使得线导体28不与负载导体30电连接。
[0009]支撑件12可以是一个用于该开关装置10的不导电的壳体。第一接触器16连接到支撑件12,第二接触器18也连接到支撑件12,如图1和图2中所示。
[0010]SMA元件20在一第一端部34连接到一与支撑件12相连的散热器36,在一第二端部38与一连接到第二接触器18的接触器承载器42相连。该SMA元件20可由一单晶形记忆合金(SCSMA)制成,该单晶形记忆合金可由主要包括铜-铝-镍(Cu-Al-Ni)或其他适当合金的金属合金形成。该SMA元件20还可由可在如下面所描述的受热时改变形状的其他已知合金形成。一SCSMA比传统的SMA具有多个优点,因此,该SMA元件可希望由SCSMA形成。SCSMA的优点包括极大的应变恢复,通常100%可重复并且是完全的。这在电控开关装置10在两个状态之间操作时是非常期望的,例如开状态和关状态。
[0011]在现有技术中通常理解,一种SMA材料,例如一种常规的SMA或SCSMA,通常形成为具有一原始形状。该SMA材料其后可变形为一变形的形状,同时保持在一低于该SMA材料的转变温度的温度。在将该SMA材料加热到其转变温度后,该SMA材料从其变形形状转变回其原始形状。在该SMA材料低于其转变温度进行冷却后,该SMA材料可回到变形形状。
[0012]回到该实施例中,SMA元件20设置为在一第一形状与响应于将该SMA元件加热到一转变温度的一不同的第二形状之间转变。更具体来说,该SMA元件20设置为在一第一形状与响应于将该SMA元件20加热到转变温度的一不同的第二形状之间转变。在所描述的实施例中,该SMA元件20是一细长的金属丝,当在第一形状与第二形状之间改变时,其长度发生变化。第一形状比第二形状相对更短。当电脉冲应用到该SMA元件20,以将该SMA元件加热到高于转变温度时,该SMA元件20从其相对较长的第一形状缩短到其相对较短的第二形状。该SMA元件20的此种收缩或长度减小导致承载器42移动,这使得第二接触器18相对于第一接触器16移动。当该SMA元件20由应用到其上的电脉冲加热到转变温度时,该SMA元件20的长度收缩一段,以足以将承载器42从图1所示的位置移动到图2所示的位置。
[0013]所示实施例中的散热器36由铝或其他适合的导热材料形成。该散热器36设置为在电脉冲应用到该SMA元件20,以将该SMA元件20升高到转变温度已经停止之后将该SMA元件20迅速冷却到一低于转变温度的温度。散热器36通过从SMA元件20带走热量,例如通过将热量扩散到周围环境而以已知的方式操作。
[0014]如上所述,该SMA元件20的第二端38与承载器42相连,这导致SMA元件20通过承载器42可操作地与第二接触器18相连。可设置一弹簧50,以将承载器42朝图1中所示的一第一位置推,将接触器14置于开的位置。该弹簧50倚靠支撑件12,以将承载器42朝图1所示的位置推。当SMA元件20被加热到高于转变温度时,该SMA元件20从图1所示的第一形状收缩到图2所示的第二形状,使得承载器42克服弹簧50的推力(按照图2中所示的方向)向上移动。承载器42的该移动使第二接触器18朝第一接触器16移动,使所述接触器置于图2所示的关的位置。
[0015]传感器22位于SMA元件20上或与其相邻,并设置为检测SMA元件20的温度。该传感器22可与SMA元件20相接触和/或与散热器36接触,以测量或检测SMA元件20的温度。传感器22还可与SMA元件20间隔开,并使用已知技术,例如IR技术,来测量或检测该SMA元件20的温度。
[0017]控制器24可在一预热状态与一转变状态之间控制传递给SMA元件20的电脉冲。在所示实施例中的该电控开关装置10中,控制器24可控制传递给SMA元件20的电脉冲,以将该SMA元件预加热到一低于转变温度的期望温度。同样,在该预热状态中,SMA元件20保持在图1中所示的第一形状,但SMA元件20的温度可高于周围环境。例如,在该预热状态中,SMA元件20的温度可以比转变温度低大约10度-20度C,以便当希望改变SMA元件20的形状时,该SMA元件20可更迅速地从第一形状转变为第二形状,因为该SMA元件20的温度与转变温度之间的温差相对于将SMA元件20保持在环境温度来说更小。
[0018]如上所述,控制器24接收来自传感器22的指示该SMA元件20的检测温度的信号。该控制器24设置为控制电脉冲,同时使该电脉冲可传递至SMA元件20,使被检测的温度低于转变温度,但通常高于环境温度。该控制器24设置为将由传感器22所检测到的检测温度与该期望温度进行对比,并基于该检测温度与该期望温度之间的比较结果调整该电脉冲。例如,在预热状态,该所期望温度可以是一第一期望温度,该第一期望温度低于转变温度大约10-20度C。同样,该控制器24可将指示SMA元件20的实际温度的该检测温度与稍微低于转变温度的该第一期望温度进行对比。如果检测温度不在低于转变温度大约10-20度C的范围内,则控制器24可调整该信号,以传递更多的能量到SMA元件20来增加SMA元件20的温度。该控制器24还设置为控制该电脉冲,同时使该电脉冲可传递至SMA元件20,以将SMA元件20加热到一第二期望温度,该第二期望温度大于或等于转变温度。在该转变状态过程中传递至SMA元件20的能量的量足以将该SMA元件20加热到转变温度或高于转变温度,使得SMA元件20从第一形状转变到该不同的第二形状。如上文中所解释的那样,这可导致SMA元件20缩短,使承载器42从图1中所示的位置移向图2中所示的位置,以关闭接触器14,将该电控开关装置置于开的状态。通过将来自传感器22的指示SMA元件20的温度的信号提供给控制器24,控制器24可调节该电脉冲,以补偿在该期望温度与SMA元件20的检测(或实际)温度之间的差异(或误差)。
[0019]一种操作例如图1和图2中的开关装置10的操作电控开关装置的方法,包括将一电脉冲传递给一SMA元件,例如SMA元件20,以将该SMA元件加热到一低于转变温度的期望温度。在此阶段过程中,例如,控制器24控制所述电脉冲,使得该电脉冲在一预热状态中将该SMA元件20加热到低于转变温度的一第一期望温度。该方法还包括调节传递给该SMA元件20的电脉冲,以将该SMA元件20的检测温度保持在大约此期望温度。如上所述,例如,传递给该SMA元件20的电脉冲可被调节,使得该期望温度低于转变温度大约10-20度C。控制器24可编程为将SMA元件20保持在该期望温度范围内,并调节该期望温度与该检测温度之间的任何误差。当希望将SMA元件20从第一形状变为第二形状时,这使得可在第一形状与第二形状之间更快地转变。
[0020]该方法还包括使用如图1和图2中所示的传感器22来检测该SMA元件20的检测温度。该方法还包括在与传感器联通的一控制器中,例如在控制器24中将该可由传感器22所检测的检测温度与所述期望温度进行对比。该电控开关装置可在开的状态与关的状态之间操作。该方法还包括在控制器24中接收一信号,以改变该电控开关装置的开/关状态。该控制器24可从该电控开关装置10的外侧接收此状态改变信号。该方法还包括在接收到一信号,该控制器24改变该电控开关装置的开/关状态的情况下调节传递给SMA元件20的电脉冲,以将该SMA元件20加热到大于或等于转变温度的一第二期望温度。换句话说,当希望将接触器14从图1中所示的位置改变到图2中所示的位置时,可传递一信号给控制器24,于是控制器24可调节传递给SMA元件20的电脉冲。该方法还可包括在控制器24中接收另一信号,以改变该电控开关装置10的状态。例如,在控制器14位于图2中所示的位置时,控制器24可接收另一信号,以将接触器置于开的位置。同样,该方法还可包括停止向SMA元件20传递电脉冲,这使得SMA元件20可从图2所示的第二形状转变回图1所示的第一形状。热量从SMA元件20消散到散热器36中,这降低了SMA元件20的温度,使得SMA元件可从第二形状(图2)移回图1所示的第一形状。同样,停止向SMA元件20传递电脉冲还可包括停止传递电脉冲,直到SMA元件20达到低于转变温度大约10-20度C的一第一期望温度。当保持在图1中所示的状态时,可调节传递给SMA元件20的电脉冲,以将SMA元件20的检测温度保持在低于转变温度的大约该第一期望温度。