JP2009158295A - Switch for dc power supply - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a switch for a DC power supply, which suppresses the occurrence of a surge voltage when turning on/off a switch. <P>SOLUTION: The switch for a DC power supply includes a switching element for electrically conducting or cutting off a DC supply line Wdc for supplying DC power, a push-button switch part, which has an opening/closing mechanism that rotates a reversing handle along with push-in operation of a push-button handle when the push-button handle is pushed in, drives on/off-states of contact parts S1, S2 of the switching element in accordance with the rotation of the reversing handle, and drives the contacts S1, S2 so as to return them to an off-state when the push-in operation of the push-button handle is released, a piano handle mounted above the push-button switch part so as to press the push-button handle by piano-touch operation, and a resistance element 35 and a capacitive element 36 connected to the DC supply line Wdc in parallel with the switching element and connected to each other in series. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a DC power supply switch.

  In homes and the like, DC devices driven by DC power are used. This includes a DC power supply unit that outputs DC power and a DC device as a load driven by the DC power, and the DC power is supplied to the DC device through a DC supply line connected to the output end of the DC power supply unit. For example, during a power failure of a commercial AC power supply, DC power can be supplied from a solar cell, a fuel cell, or the like to supplement the power.

A DC power supply switch is provided on a DC supply line that supplies power to the DC device (see, for example, Patent Document 1). As a switch for a DC power supply, when the push button handle is pushed in, the reversing handle is rotated in accordance with the pushing operation of the push button handle, and the contact portion of the switching element is driven in accordance with the rotation of the handle. A switch provided with a push button switch portion having an opening / closing mechanism for returning the contact portion when the push-in is released, and a piano handle attached to the upper portion of the push button switch portion to press the push button handle by a piano touch operation is preferable. Used.
JP 2004-14241 A

  By the way, such a DC power switch has a problem that when the switch is turned on and off, a surge voltage S is generated as shown by a broken line in FIG.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a DC power supply switch capable of suppressing the generation of a surge voltage when the switch is turned on and off.

  In order to solve the above-mentioned problem, in the DC power supply switch according to claim 1, the push button handle 1 and the switching element that electrically connects or disconnects the DC supply line Wdc for supplying DC power are pushed. When the push button handle 1 is pushed, the reversing handle 19 is rotated, and the contact portions S1 and S2 of the switching element are driven according to the turning of the reversing handle 19. A push button switch portion 2 having an opening / closing mechanism for driving the contact portions S1 and S2 to return, a piano handle 3 attached to an upper portion of the push button switch portion 2 to push the push button handle 1 by a piano touch operation, and a DC supply line Wdc includes a resistance element 35 and a capacitance element 36 connected in parallel to the switching element and connected in series to each other. It is characterized in.

  With such a configuration, it is possible to suppress the occurrence of a surge voltage when the switch is turned on and off.

  According to the present invention, it is possible to suppress a surge voltage from being generated when a switch is turned on and off by providing a resistance element and a capacitance element that are connected in parallel to the switching element and connected in series to the DC supply line. It is possible to prevent electrical components from being damaged.

  The embodiments described below are described assuming a detached house as a building to which the present invention is applied, but this does not preclude the application of the technical idea of the present invention to an apartment house. As shown in FIG. 2, the house H is provided with a DC power supply unit 101 that outputs DC power and a DC device 102 as a load driven by the DC power, and an output end of the DC power supply unit 101. DC power is supplied to the DC device 102 through the DC supply line Wdc connected to the. A current flowing through the DC supply line Wdc is monitored between the DC power supply unit 101 and the DC device 102. When an abnormality is detected, power is supplied from the DC power supply unit 101 to the DC device 102 on the DC supply line Wdc. A DC breaker 114 is provided for limiting or blocking the current.

  The DC supply line Wdc is used as both a DC power supply path and a communication path, and is connected to the DC supply line Wdc by superimposing a communication signal for transmitting data on a DC voltage using a high-frequency carrier wave. Enables communication between devices. This technique is similar to a power line carrier technique in which a communication signal is superimposed on an AC voltage in a power line that supplies AC power.

  The DC supply line Wdc is connected to the home server 116 via the DC power supply unit 101. The in-home server 116 is a main device for constructing a home communication network (hereinafter referred to as “home network”), and communicates with a subsystem constructed by the DC device 102 in the home network.

  In the example shown in the drawing, as an subsystem, an illumination system comprising an information equipment system K101 comprising an information-system DC device 102 such as a personal computer, a wireless access point, a router, and an IP telephone, and an illumination system DC equipment 102 such as a lighting fixture. K102, K105, an intercom system K103 including a DC device 102 for handling visitors and monitoring intruders, a residential alarm system K104 including a DC device 102 for an alarm system such as a fire detector, and the like. Each subsystem constitutes a self-supporting distributed system, and can operate even with the subsystem alone.

  The above-described DC breaker 114 is provided in association with a subsystem. In the illustrated example, four DCs are associated with the information equipment system K101, the lighting system K102 and the intercom system K103, the house alarm system K104, and the lighting system K105. A breaker 114 is provided. When a plurality of subsystems are associated with one DC breaker 114, a connection box 121 for dividing the system of the DC supply line Wdc is provided for each subsystem. In the illustrated example, a connection box 121 is provided between the illumination system K102 and the intercom system K103.

  As the information equipment system K101, there is provided an information equipment system K101 composed of a DC equipment 102 connected to a DC outlet 131 arranged in advance in the house H (constructed when the house H is constructed) in the form of a wall outlet or a floor outlet.

  The lighting systems K102 and K105 include a lighting system K102 composed of a lighting device (DC device 102) arranged in advance in the house H and a lighting device (DC device 102) connected to a hook ceiling 132 arranged in advance on the ceiling. An illumination system K105 is provided. At the time of interior construction of the house H, the contractor attaches the lighting fixture to the hook ceiling 132, or the householder himself attaches the lighting fixture.

  In addition to using an infrared remote control device, a control instruction for the lighting apparatus that is the DC device 102 constituting the lighting system K102 can be given using a communication signal from the switch 141 connected to the DC supply line Wdc. That is, the switch 141 has a communication function together with the DC device 102. In addition, a control instruction may be given by a communication signal from another DC device 102 in the home network or the home server 116 regardless of the operation of the switch 141. The instructions to the lighting fixture include lighting, extinguishing, dimming, and blinking lighting.

  Since any DC device 102 can be connected to the DC outlet 131 and the hooking ceiling 132 described above and DC power is output to the connected DC device 102, the DC outlet 131 and the hooking ceiling 132 are distinguished below. When it is not necessary, it is called “DC outlet”.

  These DC outlets have a plug-in connection port into which a contact (not shown) provided directly on the DC device 102 or a contact (not shown) provided via a connection line is inserted into the body. The contact receiver that directly contacts the contact inserted into the connection port is held by the container. That is, the direct current outlet supplies power in a contact manner. When the DC device 102 connected to the DC outlet has a communication function, a communication signal can be transmitted through the DC supply line Wdc. A communication function is provided not only in the DC device 102 but also in the DC outlet.

  The home server 116 not only is connected to the home network, but also has a connection port connected to the wide area network NT that constructs the Internet. When the in-home server 116 is connected to the wide area network NT, it is possible to receive services from the center server 200 that is a computer server connected to the wide area network NT.

  The service provided by the center server 200 includes a service that enables monitoring and control of equipment (including mainly the DC equipment 102 but also other equipment having a communication function) connected to the home network through the wide area network NT. is there. This service makes it possible to monitor and control devices connected to the home network using a communication terminal (not shown) having a browser function such as a personal computer, Internet TV, or mobile phone.

  The in-home server 116 has both functions of communication with the center server 200 connected to the wide area network NT and communication with equipment connected to the home network, and identification information on equipment in the home network ( Here, it is assumed that an IP address is used).

  The home server 116 enables monitoring and control of home devices through the center server 200 from a communication terminal connected to the wide area network NT by using a communication function with the center server 200. The center server 200 mediates between home devices and communication terminals on the wide area network NT.

  When monitoring and controlling home devices from a communication terminal, monitoring and control requests are stored in the center server 200, and the home device periodically performs one-way polling communication to monitor from the communication terminal. And receive control requests. With this operation, it is possible to monitor and control devices in the house from the communication terminal.

  Further, when an event that should be notified to the communication terminal, such as a fire detection, occurs in the home device, the home device notifies the center server 200, and the center server 200 notifies the communication terminal by e-mail.

  An important function among the communication functions with the home network in the home server 116 is the detection and management of devices constituting the home network. The home server 116 automatically detects devices connected to the home network by applying UPnP (Universal Plug and Play). The home server 116 includes a display device 117 having a browser function, and displays a list of detected devices on the display device 117. The display device 117 has a configuration with a touch panel type or an operation unit, and can perform an operation of selecting desired contents from options displayed on the screen of the display device 117. Therefore, the user (contractor or householder) of the home server 116 can monitor or control the device on the screen of the display device 117. The display device 117 may be provided separately from the home server 116.

  The in-home server 116 manages information related to device connection, and grasps the type, function, and address of the device connected to the home network. Accordingly, the devices in the home network can be operated in conjunction with each other. Information on the connection of the device is automatically detected as described above. In order to operate the device in an interlocking manner, the device itself is automatically associated with the attribute held by the device itself, and the home server 116 is configured as a personal computer. It is also possible to connect various information terminals and use the browser function of the information terminals to associate devices.

  Each device holds the relationship of the interlocking operation of the devices. Therefore, the device can operate in an interlocked manner without passing through the home server 116. By associating the linked operations for each device, for example, by operating a switch that is a device, it is possible to turn on or off the lighting fixture that is the device. In many cases, the association of the interlocking operations is performed within the subsystem, but the association beyond the subsystem is also possible.

  By the way, the DC power supply unit 101 basically generates DC power by power conversion of an AC power supply AC supplied from outside the house like a commercial power supply. In the configuration shown in the figure, the AC power source AC is input to an AC / DC converter 112 including a switching power source through a main circuit breaker 111 attached to the distribution board 110 as an internal unit. The DC power output from the AC / DC converter 112 is connected to each DC breaker 114 through the cooperative control unit 113.

  The DC power supply unit 101 is provided with a secondary battery 162 in preparation for a period in which power is not supplied from the AC power supply AC (for example, a power failure period of the commercial power supply AC). It is also possible to use a solar cell 161 or a fuel cell 163 that generates DC power. The solar battery 161, the secondary battery 162, and the fuel battery 163 are distributed power supplies with respect to the main power supply including the AC / DC converter 112 that generates DC power from the AC power supply AC. In the illustrated example, the solar cell 161, the secondary battery 162, and the fuel cell 163 include a circuit unit that controls the output voltage, and the secondary battery 162 includes a circuit unit that controls charging as well as discharging.

  Of the distributed power sources, the solar cell 161 and the fuel cell 163 are not necessarily provided, but the secondary battery 162 is preferably provided. The secondary battery 162 is charged in a timely manner by a main power source or other distributed power source, and the secondary battery 162 is discharged not only in a period in which power is not supplied from the AC power source AC but also in a timely manner as necessary. The cooperation control unit 113 performs charge / discharge of the secondary battery 162 and cooperation between the main power source and the distributed power source. That is, the cooperative control unit 113 functions as a DC power control unit that controls the distribution of power from the main power supply and the distributed power supply constituting the DC power supply unit 101 to the DC devices 102. Note that a configuration may be adopted in which the outputs of the solar cell 161, the secondary battery 162, and the fuel cell 163 are converted into AC power and used as input power of the AC / DC converter 112.

  Since the driving voltage of the DC device 102 is selected from a plurality of types of voltages depending on the device, the cooperative control unit 113 is provided with a DC / DC converter to convert the DC voltage obtained from the main power source and the distributed power source into the necessary voltage. Is desirable. Normally, one type of voltage is supplied to one subsystem (or DC device 102 connected to one DC breaker 114), but three or more wires are used for one subsystem. A plurality of types of voltages may be supplied. Alternatively, it is possible to adopt a configuration in which the DC supply line Wdc is of a two-wire type and the voltage applied between the lines is changed with time. The DC / DC converter may be provided in a plurality of dispersed manners like the DC breaker.

  In the above configuration example, only one AC / DC converter 112 is illustrated, but a plurality of AC / DC converters 112 can be arranged in parallel, and when a plurality of AC / DC converters 112 are provided. It is desirable to increase or decrease the number of AC / DC converters 112 that are operated according to the magnitude of the load.

  The AC / DC converter 112, the cooperative control unit 113, the DC breaker 114, the solar cell 161, the secondary battery 162, and the fuel cell 163 described above are provided with a communication function, and include a main power source, a distributed power source, and a DC device 102. It is possible to perform cooperative operations that deal with the load status. The communication signal used for this communication is transmitted in the form of being superimposed on the DC voltage in the same manner as the communication signal used for the DC device 102.

  In the above example, the AC / DC converter 112 is arranged in the distribution board 110 in order to convert the AC power output from the main breaker 111 into DC power by the AC / DC converter 112. On the output side, a branch breaker (not shown) provided in the distribution board 110 branches the AC supply line into a plurality of systems, and an AC / DC converter is provided on the AC supply line of each system to convert it into DC power for each system. You may employ | adopt the structure to do.

  In this case, since the DC power supply unit 101 can be provided for each floor or room of the house H, the DC power supply unit 101 can be managed for each system, and the DC device 102 that uses DC power and Since the distance of the DC supply line Wdc between the two is reduced, the power loss due to the voltage drop in the DC supply line Wdc can be reduced. Also, the main breaker 111 and the branch breaker are housed in the distribution board 110, and the AC / DC converter 112, the cooperative control unit 113, the DC breaker 114, and the home server 116 are housed in a separate board from the distribution board 110. Also good.

  As shown in FIGS. 3 and 4, the double-cut piano handle type DC power switch of this embodiment includes a push button switch unit 2 in which contact switching of two sets of contact portions S1, S2 is performed by pressing operation of the push button handle 1. One end of the push button switch 2 is pivotally supported on the upper surface of the push button switch unit 2 and the other end of the push button handle 1 is used to push down the upper surface of the push button handle 1. For example, as shown in FIG. The units S1 and S2 are inserted into the poles of the DC supply line Wdc to be used as a switching device that turns on and off the power to the load L such as a motor.

  The body 4 of the pushbutton switch unit 2 has a synthetic resin body 4a having an upper surface opening and locking projections 30 and 30 formed near both ends of both side surfaces of the body 4a. And a cover 4b made of synthetic resin that is fixed to the body 4a by being locked in the locking holes 32, 32 of the assembly pieces 31, 31 using the elasticity of the assembly piece 31. The size corresponds to the module size of one standardized ready-made embedded wiring device.

  The cover 4b is provided with a pair of locking claws 5 and 5 projecting from both end surfaces so that the cover 4b can be detachably attached to the mounting frame 7 used when embedding a ready-made wiring device. A space 6 is formed in the back portion of the locking claw 5 so that the locking claw 5 is elastically bent backward. Accordingly, by locking the latching claws 5 and 5 to the mounting frame 7 for a ready-made wiring device and detachably attaching the push button switch unit 2, a wall surface or the like can be obtained in the same manner as a ready-made embedded wiring device. It can be buried in the construction surface.

  On the other hand, the body 4a has two connection terminal storage portions 8 formed in one end portion, two connection terminal storage portions 9 formed in the other end portion, and two central storage portions 15 formed in the center portion. The two connection terminal storage portions 8 at one end each store two terminal plates 11 each having a lock spring 10 incorporated therein, and the two connection terminal storage portions 9 at the other end each have a lock spring. The two terminal plates 12 having the interior 10 'are accommodated. In the figure, 13 and 13 'are release buttons for releasing the electric wires of the two lock springs 10, 10, 10' and 10 'arranged on both sides of the body 4a, and 34 is released by inserting a jig. A release hole for releasing the button 13 (or 13 '), and 29 is an electric wire insertion hole.

  The terminal plate 11, the lock spring 10, the release button 13, and the terminal plate 12, the lock spring 10 ′, and the release button 13 ′ constitute a known quick connection terminal portion.

  Here, each terminal plate 12 is formed with an extended piece 12a to which a fixed contact 14 is fixed, and each extended piece 12a is extended and disposed in a corresponding central storage portion 15 of the body 4a. In addition, a support piece 11 a is formed at the lower end of each terminal plate 11 so as to extend and be arranged at the bottom of the corresponding central storage portion 15. And on each support piece 11a arrange | positioned in the center accommodating part 15, the lower end of the opening-closing body 16 which consists of metal plates is rotatably supported.

  Each opening / closing body 16 is fitted with a protrusion provided at the lower side end in a V-shaped position restricting recess 17 formed on the inner wall of the corresponding central storage portion 15, with the lower portion of the position restricting recess 17 as the center. It is pivotally supported. Further, each open / close body 16 is provided with a movable contact 18, and the movable contact 18 contacts and separates from the fixed contact 14 in accordance with the rotation of the open / close body 16, and the electrical connection between the terminal plate 11 and the terminal plate 12 is performed. The contact portion S1 or S2 that performs the proper connection and disconnection is configured with the corresponding fixed contact 14.

  As described above, one fixed contact 14 and one movable contact 18 constitute one set of contact portions S1 or S2, and two sets of contact portions S1 and S2 are simultaneously opened and closed to constitute a double-cut switch portion. .

  The two opening / closing bodies 16, 16 for opening / closing the contact portions S 1, S 2 are configured to be simultaneously driven by the rotation of one reversing handle 19. That is, two cylindrical portions 19a opened downward are arranged in parallel at the lower portion of the reversing handle 19, and the coil springs 20 are respectively accommodated in these two cylindrical portions 19a, and the lower portions of the respective coil springs 20 correspond. The opening / closing body 16 is engaged with the upper edge of the opening / closing body 16, and the opening / closing bodies 16 are driven simultaneously according to the rotation of the reversing handle 19. Therefore, each said cylinder part 19a comprises the opening-and-closing body operation part for operating each opening-and-closing body 16 of both contact part S1, S2.

  Further, the reversing handle 19 is fitted into the bearings 21 formed on the inner wall of the central opening of the ceiling surface of the cover 4b so that the inverted triangular shafts 19b provided on both sides can rotate freely from below when the cover 4b is attached. It is like that. Engaging protrusions 23 that engage with slide cams 22 to be described later are provided at both upper ends.

  The push button handle 1 is attached to the cover 4b so as to be movable up and down, and is always urged upward by a return spring 24 disposed below.

  The slide cam 22 is formed with a hooking cam body 25 slidably engaged with the hooking protrusion 23 of the reversing handle 19 on the lower surface of both ends. The slide cam 22 is attached to the lower surface side of the push button handle 1 so as to be slidable in both directions. A protrusion (not shown) formed on the lower surface of the push button handle 1 is inserted between a pair of elastic pieces 26 formed inside, and a restoring force is applied by the elastic pieces 26.

  Here, the opening / closing mechanism of the push button switch unit 2 used in the present embodiment includes the opening / closing body 16, the slide cam 22, the reversing handle 19, and the coil spring 20.

  As shown in FIG. 3 (b), the piano handle 3 is provided with a pair of turning recesses (not shown) from the lower surface on the pivot end side, and is detached from the push button switch portion 2 from the lower surface on the pressing operation end side. A pair of retaining pieces 27 for stopping are suspended. The pivot recess is pivotably engaged with a shaft portion 28 formed on the cover 4b, and the retaining piece 27 is inserted into the space 6 so that the push button switch portion 2 is mounted. When the pressing operation end side on the side of the retaining piece 27 is pressed, it rotates in a piano touch manner around the shaft portion 28. The push button handle 1 of the push button switch unit 2 is pushed downward by the rotation of the piano handle 3.

  Next, based on FIG. 6, operation | movement of the pushbutton switch part 2 is demonstrated easily. FIG. 6A shows a state in which neither of the contact points S1 and S2 of the push button switch unit 2 is off and the piano handle 3 shown in FIG. FIG. 6B shows a state in which the piano handle 3 is pushed and operated while both the contact portions S1 and S2 of the push button switch portion 2 are on.

  If the piano handle 3 shown in FIG. 3B is pushed in the state shown in FIG. 6A, the push button handle 1 is pushed down against the return spring 24 as the piano handle 3 is pushed. When the push button handle 1 is pushed down, the slide cam 22 is lowered. Then, the engagement cam body 25 on the right side of the slide cam 22 in the drawing hits the engagement protrusion 23 on the right side of the reversing handle 19, whereby the reversing handle 19 is rotated rightward in the drawing. At this time, the slide cam 22 slides to the right in the drawing as the reversing handle 19 rotates. When the reversing handle 19 is rotated in this way, both the opening / closing bodies 16 connected to the lower end of the coil spring 20 are rotated to the left in the figure, and the movable contacts 18 of the opening / closing body 16 respectively correspond. The opening / closing body 16 cannot be rotated any more due to contact with the fixed contact 14. At this position, the fixed contact 14 is provided so that the line connecting the upper end and the lower end of the opening / closing body 16 is slightly inclined to the fixed contact 14 side with respect to the line perpendicular to the bottom surface of the central storage portion 15. The extending piece 12a of the terminal plate 12 is formed and arranged so as to be perpendicular to the bottom surface, and the protruding amount of the movable contact 18, the position of the lower end of the opening / closing body 16 and the like are set.

  Thus, when the movable contact 18 comes into contact with the fixed contact 14, the push button handle 1 can no longer be pushed down. At this position, the coil spring 20 is not reversed. Accordingly, when the pressing force of the piano handle 3 is released at this position, the push button handle 1 is pushed up by the return spring 24, and at this time, the piano handle 3 returns to the original state. At the same time, the slide cam 22 is also slid and returned to the center by the spring force of the elastic piece 26, and the reversing handle 19 and the opening / closing body 16 are also rotated and returned to the state shown in FIG. The movable contacts 18 are separated from the fixed contacts 14 by the return of the two opening / closing bodies 16, and the contact portions S1 and S2 return from the on state to the off state. The return position of the opening / closing body 16 is restricted to a fixed position by a fall prevention rib 33 formed from the bottom of the central storage portion 15.

  Here, even if one of the contact portions S1 or S2 is welded, the power to the load L can be cut off by separating the other.

  In the present embodiment, the contact position of the movable contact 18 with respect to the fixed contact 14 is changed from the position where the coil spring 20 is reversed and the reversing handle 19 is reversed and rotated to the position before each is reversed. The components of the existing double-sided DC power switch that opens and closes the contact portions S1 and S2 by the reversing operation can be used, so that the components can be shared.

  In the present invention, as shown in FIG. 1, the DC supply line Wdc is provided with a resistance element 35 and a capacitive element 36 connected in series with each other in parallel with the switching element having the contact portions S1 and S2. .

  As a result, the piano handle 3 is pressed and rotated in a piano touch manner, and when the push button handle 1 of the push button switch portion 2 is pushed down, the contact portion S1 and / or S2 is closed and the switching element is turned on. As shown in the solid line of FIG. 7, the capacitor element is charged and the surge voltage S can be prevented from being generated as shown by the broken line. In addition, when the point S1 or / and S2 is opened by pressing the piano handle 3 and the switching element is turned off, the charged charge of the capacitive element is discharged and the surge voltage S is generated. Can be prevented.

  In the present invention, it is possible to suppress the generation of a surge voltage when the switch is turned on and off, and it is possible to prevent electrical components from being damaged.

It is a wiring diagram explaining the principal part of this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a whole conceptual diagram when applying DC equipment including the switch for DC power supplies of this invention to an apartment house. (A) is a front view of the switch for direct current power supplies of this invention, (b) is a side view, (c) is a bottom view. It is a disassembled perspective view of the switch for DC power supplies used for the same as the above. It is a schematic wiring diagram which shows the usage example same as the above. (A) (b) is operation | movement explanatory drawing of the switch for DC power supplies used for the same as the above. It is explanatory drawing explaining suppression of the surge voltage in this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Push button handle 19 Inversion handle 2 Push button switch part 3 Piano handle 35 Resistance element 36 Capacitance element S1 Contact part S2 Contact part Wdc DC supply line

Claims (1)

  A switching element that electrically connects or disconnects a DC supply line for supplying DC power, and when the push button handle is pushed, the reversing handle is rotated in accordance with the pushing operation of the push button handle. A push button switch portion provided with an opening / closing mechanism for driving the contact portion of the switching element in response to the movement and returning the contact portion when the push button handle is released, and the push button handle attached to the upper portion of the push button switch portion. A switch for a DC power source, comprising: a piano handle that is pressed by a piano touch operation; and a resistance element and a capacitance element that are connected to the DC supply line in parallel with the switching element and connected in series to each other.

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