Current detection device

Abstract

This invention provides a current detection device that is advantageous for miniaturization and has a short winding wire length. The current detection device (1) includes: a current path (16) through which a first current (ia) flows and a current path (17) through which a second current (ib) flows; switching elements (131, 132, 133, 134) that switch the current path (16) and the current path (17) to allow the first current (ia) and the second current (ib) to flow alternately; a common coil section (151) through which an induced current flows via the first current (ia) and the second current (ib); and a deflecting current path (170) that allows the first induced current (ia) flowing through the coil section (151) via the first current (ia) to flow through the coil section (151). i ) and the second induced current (ib) flowing in the coil section (151) through the second current (ib) i Alternation.

Description

Technical Field

[0001] This invention relates to a current detection device. Background Technology

[0002] From an energy-saving perspective, power monitoring systems are installed in various devices. Within these systems, a device called a current transformer (CT) is included in the current-measuring section. A current transformer converts the alternating current to be measured into a secondary current corresponding to the turns ratio of the coil. Such a current transformer is described, for example, in Patent Document 1. The power supply device described in Patent Document 1 has two primary windings connected in parallel, and the current flowing through the two primary windings is controlled by a drive switch. The current flowing through the primary windings is detected using two current transformers.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2010-41814 Summary of the Invention

[0006] The problem the invention aims to solve

[0007] The power supply device described in Patent Document 1 uses multiple current transformers to detect current and uses this current to control the drive switch. However, if multiple current transformers for current detection are configured and the current flowing through the bridge arms of the full-bridge circuit is inserted into each current transformer, the space required to configure the current transformers in the device increases, thus making the device larger. In addition, the length of the wiring wound in the device increases. Wiring length is a useful factor for surge noise and circuit drive stability; from the viewpoint of reducing surge noise and ensuring circuit drive stability, a short wiring length is desirable.

[0008] The present invention was made in view of the above-mentioned points. The present invention relates to a current detection device that is advantageous for miniaturization and can shorten the length of the wound wiring.

[0009] Solution for solving the problem

[0010] The current detection device of the present invention includes: a first current path through which a first current flows and a second current path through which a second current flows; a switching element that switches the first current path and the second current path to allow the first current and the second current to flow alternately; a common coil section through which an induced current flows via the first current and the second current; and a current alternation section that alternates the induced current flowing through the coil section via the first current and the induced current flowing through the coil section via the second current.

[0011] The effects of the invention

[0012] This invention relates to a current detection device that is advantageous for miniaturization and has a short winding wire length. Attached Figure Description

[0013] Figure 1 This is a diagram illustrating a current measuring system including the current detection device of the first embodiment of the present invention.

[0014] Figure 2 It is used for explanation Figure 1 The diagram shows a schematic longitudinal cross-sectional view of the coil section.

[0015] Figure 3 (a) is a schematic diagram representing the first induced current, (b) is a schematic diagram representing the second induced current, and (c) is a schematic diagram representing the state in which the first induced current and the second induced current are combined.

[0016] Figure 4 This is a diagram illustrating the second embodiment of the present invention, and is a schematic diagram showing the upper surface of the annular coil.

[0017] Figure 5 (a) is a diagram illustrating a variation 1 of the first embodiment, and (b) is a diagram illustrating a variation 1 of the second embodiment.

[0018] Figure 6 (a) is another figure used to illustrate a variation 1 of the first embodiment, and (b) is another figure used to illustrate a variation 1 of the second embodiment.

[0019] Figure 7 (a) is a diagram illustrating a variation 2 of the first embodiment, and (b) is another diagram illustrating a variation 2 of the first embodiment.

[0020] Explanation of reference numerals in the attached figures

[0021] 1: Current detection device; 2: Power supply unit; 3: Current determination unit; 11: DC power supply; 15: Current transformer; 16, 17: Current path; 18: Full-bridge control circuit; 19, 20, 46, 47: Coils; 21: Load; 28: Push-pull control circuit; 31, 32: Diodes; 33: Current determination circuit; 45: Ring coil; 45a: Upper surface; 100: Current measurement system; 131, 132, 133, 134: Switching elements; 150: Core; 151: Coil unit; 152: First coil; 153: Second coil; 161, 171: Coil ends; 170: Current path reversal; A, B, C: Output terminals. Detailed Implementation

[0022] The first and second embodiments of the present invention will now be described. Both the first and second embodiments represent the technical concept and structural examples of the present invention, and are not intended to limit specific structures, dimensions, or shapes. Furthermore, the accompanying drawings used in the first and second embodiments are primarily schematic representations of the functions, configurations, and interrelationships of the components, and do not accurately depict their dimensions, shapes, aspect ratios, etc.

[0023] [First Implementation Method]

[0024] Figure 1 This diagram illustrates a current measuring system 100 including the current sensing device 1 of the first embodiment. The current measuring system 100 includes: a current sensing device 1; a power supply unit 2, which includes a load 21 that receives power from a DC power supply 11; and a current determination unit 3, which rectifies the current detected by the current sensing device 1 to determine the current value. The current determination unit 3 determines the value of the current detected by the current sensing device 1 and controls the switching element of the current sensing device 1. At this time, the current determination unit 3 can also stop or start the operation of the current sensing device 1 based on the determination result.

[0025] (Current detection device)

[0026] The current detection device 1 includes a current path 16 and a current path 17. Current path 16 is a first current path through which a first current ia flows, and current path 17 is a second current path through which a second current ib flows. Furthermore, the current detection device 1 includes switching elements 131, 132, 133, and 134 that switch the current path 16 and current path 17 to allow the first current ia and the second current ib to flow alternately; and a common coil section 151 through which an induced current flows via the first current ia and the second current ib. The coil section 151 is the coil portion of the current transformer 15, and a detection signal is output from the output terminals A and C of the coil section 151 based on the induced electromotive force generated in the coil section 151.

[0027] Switching elements 132 and 133 constitute a first transistor pair, which includes two transistor elements that allow a first current ia to flow through current path 16. Additionally, switching elements 131 and 134 constitute a second transistor pair, which includes two transistor elements that allow a second current ib to flow through current path 17. Switching elements 131-134 constitute a full-bridge circuit, with current paths 16 and 17 being the bridge arms of the full-bridge circuit. The first current ia flowing through current path 16 and the second current ib flowing through current path 17 are the bridge arm currents of the full-bridge circuit.

[0028] In a full-bridge circuit like this, for example, switching elements 132 and 133 are turned on at the same timing, during which switching elements 131 and 134 are in the off state. At this time, in the current detection device 1, a current flow path (current path) is formed from switching element 132 to coil end 171, coil 19, coil end 161, and switching element 133. Current path 16 refers to the portion between switching elements 132 and 133 in such a current path. In this state, the current flowing from the DC power supply 11 flows between the source and drain of switching element 132 and into current path 17. The current flowing into current path 17 becomes a first current ia from coil end 171 through coil 19, passes between the source and drain of switching element 133, and is fed back to the current detection device 1.

[0029] Next, in the first embodiment, switching elements 131 and 134 are turned on at the same timing, during which switching elements 132 and 133 are in the off state. At this time, a current path is formed in the current detection device 1 from switching element 131 to coil end 161, coil 19, coil end 171, and switching element 134. Current path 17 refers to the portion between switching elements 131 and 134 in such a current path. In this state, the current flowing from the DC power supply 11 passes between the source and drain of switching element 131, and flows from coil end 171 through coil 19 into the redirecting current path 170. The current flowing into the redirecting current path 170 becomes the second current ib, and is fed back to the current detection device 1 through the source and drain of switching element 134.

[0030] The coil section 151 generates an induced current by the current flowing between the two switching elements 132 and 133 or between the two switching elements 131 and 134.

[0031] Furthermore, the current detection device 1 includes: a DC power supply 11; and a full-bridge control circuit 18, which applies voltage to the gates of switching elements 131-134 to control the switching elements 131-134. The full-bridge control circuit 18 controls the switching elements 132 and 133 to be turned on at the same timing, and the switching elements 131 and 134 to be turned off during this period. At this time, in the current detection device 1, a current path is formed from the DC power supply 11 to the current path 16 and from the switching element 133 on the current path 16 back to the DC power supply 11, as described above.

[0032] Furthermore, the full-bridge control circuit 18 controls the switching elements 131 and 134 to be turned on at the same timing, while the switching elements 132 and 133 are turned off during this period. At this time, in the current detection device 1, a current path is formed from the DC power supply 11 to the current path 17 and from the switching element 134 on the current path 17 back to the DC power supply 11, as described above.

[0033] Such a full-bridge control circuit 18 can also utilize small computers such as microcomputers.

[0034] In addition, in the first embodiment, the coil section 151 has an output terminal B in addition to output terminals A and C, for a total of three output terminals A, B, and C. One of the output terminals B is a center tap led out from the middle of the coil section 151. When the center tap is provided in the coil section 151, the coil section 151 operates like two half-wave circuits, thereby performing double-wave rectification on the current flowing through the coil section 151. By performing double-wave rectification in this way, the first current ia and the second current ib can be detected with their respective positive side peak values, thereby enabling the determination of both the first current ia and the second current ib using a determination reference value in the current determination circuit.

[0035] Furthermore, the first embodiment includes a current alternation section that alternates the induced current flowing through the coil section 151 via the first current ia and the induced current flowing through the coil section 151 via the second current ib. Here, alternating the induced current means that the induced current generated in the coil section 151 by the induced electromotive force flows in a manner that reverses the flow direction with a fixed period. The induced current flows in the coil section 151 via the direct current first current ia and the second current ib (hereinafter referred to as "the switching on and off of the first current ia, the switching on and off of the second current ib"). Such an induced current is represented by a waveform having a period corresponding to the switching on and off of the first current ia and the second current ib. In addition, in the first embodiment, since the flow directions of the first current ia and the second current ib are reversed, the first induced current ia flowing through the coil section 151 via the first current ia... i The phase of the second induced current ib flowing through the coil section 151 is the same as that of the second current ib. i Their phases are reversed.

[0036] like Figure 1 As shown, the current detection device 1 of the first embodiment includes a current path 17 for the second current ib to flow in the opposite direction to the flow direction of the first current ia. An induced current is generated in the coil section 151 by the current flowing through the redirected current path 170. As described above, by reversing the flow directions of the first current ia and the second current ib, the first induced current ia is generated. i With the second induced current ib i Since they alternate, in the first embodiment, the current path 170 functions as a current alternation section. In other words, the first embodiment generates an alternating current based on the first DC current ia and the second DC current ib by alternately turning on and off the switching elements 132, 133 and 131, 134.

[0037] Figure 2 This is a schematic diagram for illustrating the coil section 151, showing only the longitudinal section of the coil section 151 with respect to the secondary side. Figure 2 The coil section 151 shown uses a coil section with a central post in the core 150. Such a core may be, for example, EI-shaped, ER-shaped, etc. The coil section 151 includes a core 150 such as an iron core, and a first coil 152 and a second coil 153 wound around the core 150. The first coil 152 and the second coil 153 are double-wound onto a single core 150. Furthermore, in... Figure 2 In the diagram, the first coil 152 and the second coil 153 are distinguished by the inclination of the shadow line of the cross section.

[0038] like Figure 2As shown, double-wire winding refers to winding two wires side-by-side along the length of core 150. Alternatively, double-wire winding can also involve winding two wires after twisting them together.

[0039] The aforementioned double-wound coil section 151, due to the good connection between the coils, reduces leakage inductance and lowers operating impedance. Such a coil section 151 is a preferred structure for a current transformer 15 that measures the alternating current flowing through two current paths 16 and 17.

[0040] (Power Supply Department)

[0041] The power supply unit 2 includes: a coil 19, one end 161 of which is connected to the current path 16, and the other end 171 of which is connected to the current path 17; and a coil 20 separate from the coil 19. The coil 19 and coil 20 constitute an insulated transformer, and an induced electromotive force is generated in the coil 20 by a first current ia or a second current ib flowing through the coil 19. The induced electromotive force generated in the coil 20 is supplied to the load 21. Furthermore, when the current measuring system 100 is applied, for example, to in-vehicle equipment, a starter motor, air conditioner, car navigation system, etc., can become the load 21.

[0042] (Current Determination Section)

[0043] The current determination unit 3 is connected to the output terminals A, B, and C of the coil unit 151. Furthermore, the current determination unit 3 includes a current determination circuit 33, which receives a first induced current ia from the output terminals A and C. i Second induced current ib i The current supplied to the power supply unit 2 is determined. A diode 31 is provided between the output terminal A and the current determination circuit 33, and a diode 32 is provided between the output terminal C and the current determination circuit 33. Both diodes 31 and 32 cause the current to flow towards the current determination circuit 33. The first induced current ia is output from the output terminal A. i and the second induced current ib output from output terminal C i The current is combined and input to the current determination circuit 33.

[0044] Figure 3 (a) represents the first induced current ia i A schematic diagram. Figure 3 (b) represents the second induced current ib. i A schematic diagram. (See example.) Figure 3 of (a), Figure 3 As shown in (b), the first induced current ia i Second induced current ib iThe waveforms are those with opposite phases and equal amplitudes, with the output terminal B as the reference. Figure 3 (c) represents the first induced current ia i With the second induced current ib i A diagram of the synthesized waveform.

[0045] Current determination circuit 33 detects the current at the time of detection. Figure 3 The value of the current output in the positive direction of the composite waveform shown in (c) (hereinafter also referred to as "high current side") is then output. Furthermore, the detected value is output to the full-bridge control circuit 18. The full-bridge control circuit 18 can, for example, turn on and off switching elements 132, 133 and switching elements 131, 134 based on the input timing of the signal representing the detected value. Additionally, the full-bridge control circuit 18 can determine the values ​​of the first current ia and the second current ib based on the detected value on the high current side, and determine the amount of supplied current and any abnormalities. In this case, the full-bridge control circuit 18 can also disconnect all switching elements 131 to 134 to stop supplying the first current ia and the second current ib to the load 21.

[0046] Furthermore, the values ​​of the first current ia and the second current ib can be determined, for example, by pre-comparing the values ​​of the first current ia and the second current ib with the first induced current ia generated based on the first current ia and the second current ib. i Second induced current ib i The values ​​are mapped accordingly. The current determination circuit 33 can also pre-store the first induced current ia corresponding to the threshold values ​​of the first current ia and the second current ib that are judged to be abnormal. i Second induced current ib i The value of the first induced current ia input i Second induced current ib i If the value exceeds or falls below the threshold, the switching elements 131 to 134 will be disconnected.

[0047] Furthermore, the current determination circuit 33 can also output the detected value to an external device (not shown). Based on the detected value on the high current side, the external processing unit calculates the current supplied to the coil 19, and then calculates the power supplied to the load 21. The detected value detected by the current determination circuit 33 can be used, for example, for constant current control of the current detection device 1 or overcurrent protection (OCP) control.

[0048] Next, the overall operation of the current measuring system 100 described above will be explained. In the current detection device 1, firstly, the full-bridge control circuit 18 turns on the switching elements 132 and 133 and turns off the switching elements 131 and 134. At this time, the current flowing from the DC power supply 11, as the first current ia, passes through the current path 16 and induces a first induced current ia in the coil section 151. i .

[0049] Next, the full-bridge control circuit 18 turns on switching elements 131 and 134 and turns off switching elements 132 and 133. At this time, the current flowing out of the DC power supply 11, as a second current ib flowing in the opposite direction, passes through the current path 17 and induces a second induced current ib in the coil section 151. i The result is that the first induced current ia i Second induced current ib i Output from output terminal A or output terminal C.

[0050] The first induced current ia output i Second induced current ib i The currents are combined and input to the current determination circuit 33. At this time, the first embodiment can reverse the current flowing through current path 16 and current path 17 relative to the other, thereby generating a first induced current ia from the current flowing through current path 16. i The phase of the second induced current ib generated by the current flowing through current path 17. i Their phases are opposite. Furthermore, it is possible to determine the phase of the first induced current ia. i With the second induced current ib i The synthesized waveform is used to detect the first induced current ia. i Second induced current ib i The value on the high current side.

[0051] According to this first embodiment, both the first current ia and the second current ib can be measured using a shared current transformer 15. Compared to the structure in Patent Document 1 described above, which measures the first current ia and the second current ib using different current transformers, this structure reduces the number of current transformers. Since current transformers have coils, they require more space to be installed; therefore, reducing the number of current transformers contributes to the overall miniaturization of the device.

[0052] Furthermore, in small devices, the length of the winding wiring within the device can be shortened. Therefore, in the first embodiment, the wiring is less susceptible to surge current and noise, which improves signal quality and drive reliability.

[0053] In the first embodiment, compared to a structure where the first current ia and the second current ib are measured separately by different current transformers, the current on the primary side becomes twice as large. However, by alternating the first current ia and the second current ib in the first embodiment, the coil section 151 with the same core size and number of turns as in the case of using two current transformers can be used in the current transformer 15.

[0054] Furthermore, in the first embodiment, by double-winding the coil portion 151 of a current transformer 15, even a single coil can effectively detect the current flowing through the two current paths 16 and 17, thereby achieving the same measurement accuracy as structures measured by different current transformers. In the current measurement system 100 equipped with a single current transformer 15, the current determination circuit 33 can also be a single unit, which is more conducive to the miniaturization of the device.

[0055] [Second Implementation]

[0056] Next, the second embodiment of the present invention will be described.

[0057] Figure 4 This diagram illustrates the second embodiment and shows the upper surface 45a of the toroidal coil 45. In the second embodiment, the coil portion 151 is a toroidal coil 45 having a toroidal iron core (not shown), which differs from the first embodiment using a core 150 with a central post. The toroidal iron core is a ring-shaped core formed by aligning the beginning and end of a strip-shaped strong magnetic material with a rectangular cross-section. Examples of strong magnetic materials include iron, nickel, cobalt, and their alloys.

[0058] like Figure 4 As shown, the loop coil 45 has a circular shape when viewed from above. Figure 4 The diagram shows one side of the annular shape (e.g., upper surface 45a). Here, the other side of the annular shape (not shown) is referred to as the other side, which corresponds to the back surface of upper surface 45a. Current paths 16 and 17 are inserted into the annular coil 45. In the second embodiment, current path 17 does not have a turning current path 170; instead, in a top view of the annular coil 45, current path 17 is inserted into the annular coil 45 from upper surface 45a toward the other side. Additionally, current path 16 is inserted into the annular coil 45 from the other side toward upper surface 45a.

[0059] The loop coil 45 is fixed by the portion of current path 16 located between switching elements 131 and 133 and the portion of current path 17 located between switching elements 132 and 134. A first current ic and a second current id flowing in the same direction are supplied to current paths 16 and 17, respectively.

[0060] According to this structure, a first current ic and a second current id, each with opposite flow directions, alternately flow through the annular portion of the loop coil 45. The induced currents generated in the coil portion 151 by the first current ic and the second current id are alternating currents. In other words, in the second embodiment, the loop coil 45, the current path 17 extending from the upper surface 45a toward the back surface of the loop coil 45, and the current path 16 extending from the back surface toward the upper surface 45a of the loop coil 45 function as an alternating current section.

[0061] The second embodiment described above can measure the first current ic and the second current id by installing a loop coil 45 in the existing current path. Furthermore, in the loop coil 45, two wires can be wound side-by-side around the toroidal core for double-wire winding, or two wires can be twisted together and then wound around the toroidal core for double-wire winding. Therefore, the second embodiment can also accurately measure the currents in the two current paths 16 and 17 using a loop coil 45, just like the first embodiment.

[0062] [Variation Example]

[0063] Next, the first embodiment and the second embodiment described above, and their variations 1 and 2, will be described.

[0064] (Variation Example 1)

[0065] In Modification 1, the switching elements include switching elements 132 and 133 that allow a first current ia to flow through current path 16, and switching elements 131 and 134 that allow a second current ib to flow through current path 17. The coil section 151 generates an electromotive force by the current flowing through a portion upstream or downstream of the switching elements 132, 133 and 131, 134. That is, Modification 1 is not limited to the current transformer 15 measuring the current between switching elements 132 and 133, or between switching elements 131 and 134, but can measure the current at any position in the current paths 16 and 17.

[0066] Figure 5 Example (a) is shown below: In the current detection device 1 of the first embodiment, the coil section 151 generates an induced current by the current upstream of the switching elements 132, 133 and the switching elements 131, 134. Figure 5 The current transformer 15 shown in (a) is positioned upstream of the switching element 131, and a deflecting current path 170 is formed in the current path 17 upstream of the switching element 133.

[0067] exist Figure 5In the current detection device shown in (a), similarly to the first embodiment, coil end 161 is connected between switching element 131 and switching element 134, and coil end 171 is connected between switching element 132 and switching element 133, thereby supplying current to coil 19. Furthermore, similarly to the first embodiment, the full-bridge control circuit 18 uses switching elements 131 and 134 as a pair, and switching elements 132 and 133 as a pair, and alternately switches them on and off.

[0068] Figure 5 (b) shows an example in which the ring coil 45 of the second embodiment is positioned upstream of the switching elements 132, 133 and the switching elements 131, 134. Figure 5 The loop coil 45 shown in (b) and the current paths 16 and 17 inserted into the loop coil 45 have the same structure as in the second embodiment. However, in Figure 5 In the example shown in (b), the loop coil 45 is disposed between the DC power supply 11 and the switching element 131, and also between the DC power supply 11 and the switching element 133. Therefore, the current if that flows out of the DC power supply 11 is branched and flows into and out of the first current ic and the second current id via current path 16 and current path 17.

[0069] Figure 6 Example (a) is shown below: In the current detection device 1 of the first embodiment, the coil section 151 generates an induced current through the current downstream of the switching elements 132, 133 and the switching elements 131, 134. Figure 6 The current transformer 15 shown in (a) is located downstream of the switching element 132, and a deflecting current path 170 is formed in the current path 17 downstream of the switching element 134.

[0070] Figure 6 (b) shows an example in which the ring coil 45 of the second embodiment is positioned downstream of the switching elements 132, 133 and 131, 134. Figure 6 The loop coil 45 shown in (b) and the current paths 16 and 17 inserted into the loop coil 45 have the same structure as in the second embodiment. However, in Figure 6 In the example shown in (b), the loop coil 45 is disposed between the switching element 132 and the DC power supply 11, and is also disposed between the switching element 134 and the DC power supply 11. Therefore, the first current ic and the second current id flow into the current path 16 and the current path 17, and after flowing out, they merge and flow into the DC power supply 11 as the current ie.

[0071] (Variation Example 2)

[0072] Next, a variation of the first embodiment, example 2, will be described.

[0073] Figure 7 of (a), Figure 7 Figure (b) is a diagram illustrating the current detection device of Modification 2. Modification 2 is an example of applying the current detection device of the first embodiment to a push-pull circuit. Figure 7 (a) shows an example where the current transformer 15 is located upstream of the switching elements 131 and 132. Figure 7 (b) shows an example where the current transformer 15 is located downstream of the switching elements 131 and 132. Figure 7 of (a), Figure 7 The current detection devices shown in (b) all use a push-pull control circuit 28 to alternately turn on and off the switching elements 131 and 132. At this time, the DC current supplied from the DC power supply 11 alternately flows into the current path 16 and the current path 17, and the first induced current generated in the coil section 151 is output from the output terminals A and C.

[0074] in addition, Figure 7 of (a), Figure 7 (b) The current detection device 1 connects coil 46 to current path 16 and connects coil 47, which is separate from coil 46, to current path 17. Currents in the same direction as the first current ia are alternately supplied to coils 46 and 47. Through this operation, currents in different directions flow alternately through coils 46 and 47, generating a current in coil 20 flowing in the same direction as coil 47 through electromagnetic induction. The induced electromotive force generated in coil 20 is supplied to load 21.

[0075] The above implementation methods include the following technical concepts.

[0076] (1) A current detection device comprising: a first current path through which a first current flows and a second current path through which a second current flows; a switching element that switches the first current path and the second current path to allow the first current and the second current to flow alternately; a common coil section through which an induced current flows via the first current and the second current; and a current alternation section that alters the induced current flowing through the coil section via the first current and the induced current flowing through the coil section via the second current.

[0077] (2) According to the current detection device of (1), the coil part includes a first coil and a second coil, the first coil and the second coil being wound with two wires on a core.

[0078] (3) According to the current detection device of (1) or (2), the switching elements are a first transistor pair and a second transistor pair, the first transistor pair includes two transistor elements that allow the first current to flow in the first current path, the second transistor pair includes two transistor elements that allow the second current to flow in the second current path, and the coil portion generates an induced current by the current flowing between the two transistor elements included in the first transistor pair or between the two transistor elements included in the second transistor pair.

[0079] (4) According to the current detection device of (1) or (2), the switching element includes a first transistor pair and a second transistor pair, the first transistor pair includes two transistor elements that allow the first current to flow in the first current path, the second transistor pair includes two transistor elements that allow the second current to flow in the second current path, and the coil portion generates an electromotive force by the current flowing in a portion upstream or downstream of the first transistor pair and the second transistor pair.

[0080] (5) According to any one of (1) to (4) the current detection device, the current alternation section includes a deflection current path in the second current path, the deflection current path being used for the second current to flow in the opposite direction to the flow direction of the first current, and an induced current is generated in the coil section by the current flowing through the deflection current path.

[0081] (6) According to any one of (1) to (4) the current detection device, the coil part is wound around the toroidal iron core to form a toroidal coil, the current alternation part includes a first current path and a second current path, the first current path is inserted into the toroidal coil from one side of the toroidal shape in a top view of the toroidal coil to the other side, and the second current path is inserted into the toroidal coil from the other side of the toroidal coil to the one side in a top view of the toroidal coil.

[0082] (7) A center tap is drawn from the coil section using a current detection device according to any one of (1) to (6).

[0083] This application claims priority based on Japanese Patent Application No. 2019-133552, filed on July 19, 2019, the entire contents of which are incorporated herein by reference.

Claims

1. A current detection device, comprising: The first current path through which the first current flows and the second current path through which the second current flows; A switching element that switches between the first current path and the second current path to allow the first current and the second current to flow alternately; A current transformer capable of measuring a first current and a second current that flow alternately in a first current path and a second current path; as well as Current determination unit, The current transformer includes a coil section. An induced current is induced in the coil section by either the first current flowing through the first current path or the second current flowing through the second current path. The flow direction of the first current is opposite to the flow direction of the second current. Therefore, the phase of the first induced current induced in the coil section by the first current is opposite to the phase of the second induced current induced in the coil section by the second current. The coil section includes a first coil and a second coil, which are wound with two wires on a single core. The current determination unit can be input with the first induced current and the second induced current, which are output from the coil unit and have phases that are reversed, to determine the first current and the second current.

2. The current detection device according to claim 1, wherein, The switching element includes a first transistor pair and a second transistor pair. The first transistor pair includes two transistor elements that allow the first current to flow in the first current path, and the second transistor pair includes two transistor elements that allow the second current to flow in the second current path. The coil portion generates an induced current by the current flowing between the two transistor elements included in the first transistor pair or between the two transistor elements included in the second transistor pair.

3. The current detection device according to claim 1, wherein, The switching element includes a first transistor pair and a second transistor pair. The first transistor pair includes two transistor elements that allow the first current to flow through the first current path. The second transistor pair includes two transistor elements that allow the second current to flow through the second current path. The coil portion generates an electromotive force by the current flowing through a portion upstream or downstream of the first transistor pair and the second transistor pair.

4. The current detection device according to claim 1, wherein, The current detection device further includes a deflecting current path in the second current path, which is used for the second current to flow in the opposite direction to the flow direction of the first current, and an induced current is generated in the coil section by the current flowing through the deflecting current path.

5. The current detection device according to claim 1, wherein, The coil portion is wound around a toroidal iron core to form a toroidal coil. The first current path passes through the toroidal coil from one side of the toroidal shape in a top view to the other side. The second current path passes through the toroidal coil from the other side of the toroidal coil in a top view to the first side.

6. The current detection device according to claim 1, wherein, A center tap is drawn from the coil section.

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