Transformer winding structure and connector disconnection detection device

Abstract

To provide a transformer winding structure in which interference between winding for power transmission and winding for signal transmission is suppressed.SOLUTION: A primary connector 30p includes columnar cores Ap, Bp, Cp, and Dp arranged in the same stretching direction, a neutral columnar core Np, U-phase winding 28Up, V-phase winding 28Vp, and W-phase winding 28Wp as multi-phase power winding, and signal winding 28gp. The columnar cores Ap, Bp, Cp, and Dp are arranged in a circle in a plane intersecting their respective stretching directions, and one end is coupled to a common core Ep. The neutral columnar core Np is arranged in a position surrounded by the columnar cores Ap, Bp, Cp and Dp so as to be aligned with the respective columnar cores in the extending direction, and one end is coupled to the common core Ep. The power winding of multiple phases are provided on the columnar cores Ap, Bp, Cp and Dp such that the interlinking magnetic fluxes between them are reduced.SELECTED DRAWING: Figure 2A

Description

[Technical Field]

[0001] The present invention relates to a transformer winding structure and a connector disconnection detection device, and more particularly to a technique using a winding for signal transmission. [Background technology]

[0002] There has been extensive research into technologies that utilize the output power of batteries or technologies that charge batteries. For example, in recent years, research has been conducted into a technology called V2G (Vehicle to Grid). In V2G, power is supplied from batteries installed in electrically powered vehicles such as electric vehicles and hybrid vehicles to a power grid such as a commercial power system, and then from the power grid to the battery. Another technology related to V2G is called V2H (Vehicle to Home), which supplies power from batteries installed in electrically powered vehicles to electrical appliances used in ordinary homes, offices, etc.

[0003] Generally, devices that use batteries use a power conversion device that adjusts the power output from the battery and outputs it to a device that receives the power, or adjusts power supplied from an external source and outputs it to the battery. Some power conversion devices use multiple switching circuits and a transformer that couples the switching circuits to match the voltage applied to the external device with the battery's output voltage. Some power conversion devices also use a transformer to insulate the parts operated by the user from the battery. Furthermore, some devices have separate configurations: a device with a transformer primary winding and a device with a transformer secondary winding, and the devices on the primary winding and secondary winding sides are detachable via a connector.

[0004] The following Patent Documents 1 to 5 describe power conversion devices in which two switching circuits are coupled by a transformer. In the power conversion devices described in Patent Documents 1 to 3, a transformer is formed by coupling a connector having a primary winding with a connector having a secondary winding. The following Patent Document 4 describes a technology for performing contactless control communication using a coupling element between switching circuits that perform contactless power transmission. Patent Document 5 describes a magnetic component in which a transformer and an inductor are integrated into a single magnetic structure. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] US Patent No. 5,341,083 [Patent Document 2] US Patent Publication No. 2017 / 179765 [Patent Document 3] Patent Publication No. 2021-27281 [Patent Document 4] Japanese Patent Application Publication No. 2019-187006 [Patent Document 5] European Patent Application Publication No. 2299456 Summary of the Invention [Problem to be solved by the invention]

[0006] Generally, when two switching circuits are coupled and operated by a transformer, a control signal for synchronizing the switching operation is transmitted between one switching circuit and the other. Therefore, when a connector-type transformer is used to couple two switching circuits, it is considered to transmit not only power but also control signals via the connector in order to simplify the structure.

[0007] However, when a common connector is used to transmit power and control signals, interference may occur between the voltage or current for power transmission and the control signals, and each switching circuit may not operate ideally.

[0008] An object of the present invention is to provide a transformer winding structure in which interference between a winding for power transmission and a winding for signal transmission is suppressed. [Means for solving the problem]

[0009] The present invention is characterized by comprising: a plurality of columnar cores arranged with the same extension direction, the columnar cores being arranged circumferentially in a plane intersecting the respective extension directions, and one end of the columnar cores being connected to a common core; a neutral columnar core arranged in a position surrounded by the plurality of columnar cores with the same extension direction as each of the columnar cores and one end of the neutral columnar core being connected to the common core; multi-phase power windings provided on the plurality of columnar cores so that magnetic flux linking between them subtracts from each other; and a signal winding provided on the neutral columnar core.

[0010] Preferably, a neutral magnetic path is formed that passes through the neutral columnar core and each of the columnar cores.

[0011] Preferably, a loop in an upper winding that is one of the power windings of the multiple phases surrounds a magnetic flux generated from a figure-eight shaped loop in a lower winding that is another one of the power windings of the multiple phases.

[0012] The present invention also provides a connector disconnection detection device for use with the transformer winding structure, comprising: a switching circuit connected to the power windings of multiple phases; a signal transmission circuit connected to the signal windings; and a controller that controls the switching circuit and the signal transmission circuit, wherein the signal transmission circuit obtains a timing signal from the signal winding that defines the switching timing of the switching circuit, and the controller detects, based on the level of the timing signal, that the coupling between the transformer winding structure and other winding structures has become loose.

[0013] Preferably, the controller determines the distance between the transformer winding structure and the other winding structure based on the level of the timing signal.

[0014] Furthermore, the present invention Related technologies A connector disconnection detection device for a winding structure for a connector including a power winding of multiple phases and a signal winding comprises a switching circuit connected to the power windings of multiple phases, a signal transmission circuit connected to the signal winding, and a controller for controlling the switching circuit and the signal transmission circuit, wherein the signal transmission circuit obtains a timing signal from the signal winding that defines the switching timing of the switching circuit, and the controller detects that the coupling between the connector winding structure and another winding structure has become loose based on the level of the timing signal. do.

[0015] Preferably, the controller determines the distance between the connector winding structure and the other winding structure based on the level of the timing signal.

[0016] Preferably, the signal transmission circuit includes a damping oscillation circuit that damps oscillation of a voltage generated by the other winding structure in the signal winding.

[0017] Preferably, when the controller detects that the coupling has become loose, it stops the switching operation of the switching circuit. [Effects of the Invention]

[0018] According to the present invention, it is possible to realize a transformer winding structure in which interference between the winding for power transmission and the winding for signal transmission is suppressed. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a diagram showing a configuration of a power conversion system according to an embodiment of the present invention; [Figure 2A]A perspective view of the primary connector. [Figure 2B] This is an oblique view of the core unit of the primary connector. [Figure 2C] FIG. 2 is a perspective view of a U-phase winding, a V-phase winding, and a W-phase winding. [Figure 3] A perspective view of the secondary connector. [Figure 4] 1 is a diagram schematically illustrating a cross section and magnetic flux of a decoupling transformer. [Figure 5] 1 is a diagram schematically illustrating a cross section and magnetic flux of a decoupling transformer. [Figure 6] 10A and 10B are diagrams illustrating the relationship between the distance between connectors and the coupling coefficient, and a control timing chart. [Figure 7] 3 is a diagram illustrating a first configuration example of a primary signal transmission circuit and a secondary signal transmission circuit. FIG. [Figure 8] FIG. 10 is a diagram illustrating a second configuration example of a primary signal transmission circuit and a secondary signal transmission circuit. [Figure 9] FIG. 10 is a diagram illustrating a third configuration example of a primary signal transmission circuit and a secondary signal transmission circuit. [Figure 10] FIG. 1 shows the configuration of a primary connector equipped with five-phase power windings and one-phase signal winding. [Figure 11] FIG. 1 shows the configuration of a primary connector equipped with seven-phase power windings and one-phase signal winding. DETAILED DESCRIPTION OF THE INVENTION

[0020] Each embodiment of the present invention will be described with reference to the drawings. Identical components shown in multiple drawings will be assigned the same reference numerals to simplify the description. The terms up, down, left, and right in this specification indicate directions in the drawings. These directional terms are used for the convenience of explanation and do not limit the orientation of each component when it is arranged.

[0021] 1 shows the configuration of a power conversion system 100 according to an embodiment of the present invention. The power conversion system 100 includes a primary power conversion device 10 and a secondary power conversion device 20. The primary power conversion device 10 includes a primary switching circuit 12, a primary connector 30p, a primary DC power supply 32p, a primary signal transmission circuit 16, and a primary controller 14.

[0022] The primary switching circuit 12 includes a U-phase switching arm U, a V-phase switching arm V, a W-phase switching arm W, and a capacitor Ca. Each of the U-phase switching arm U, the V-phase switching arm V, and the W-phase switching arm W includes an upper switching element S1 and a lower switching element S2 connected in series. Each switching element may be a metal-oxide-semiconductor field-effect transistor (MOSFET) or an insulated gate bipolar transistor (IGBT). When MOSFETs are used as the switching elements, connecting two switching elements in series means connecting the source of one MOSFET to the drain of the other MOSFET. When IGBTs are used as the switching elements, connecting two switching elements in series means connecting the emitter of one IGBT to the collector of the other IGBT.

[0023] The U-phase switching arm U, the V-phase switching arm V, and the W-phase switching arm W are connected in parallel. That is, the upper ends of the upper switching elements S1 of each switching arm are connected in common, and the lower ends of the lower switching elements S2 of each switching arm are connected in common. Furthermore, a capacitor Ca is connected in parallel to the U-phase switching arm U, the V-phase switching arm V, and the W-phase switching arm W. That is, the upper end of the capacitor Ca is connected to the upper ends of each switching arm, and the lower end is connected to the lower ends of each switching arm.

[0024] The primary connector 30p has a U-phase winding 28Up, a V-phase winding 28Vp, and a W-phase winding 28Wp. One end of the U-phase winding 28Up is connected to the connection point (switching element connection point) between the upper switching element S1 and the lower switching element S2 of the U-phase switching arm U. One end of the V-phase winding 28Vp and one end of the W-phase winding 28Wp are connected to the switching element connection point of the V-phase switching arm V and the switching element connection point of the W-phase switching arm W, respectively. The other ends of the U-phase winding 28Up, the V-phase winding 28Vp, and the W-phase winding 28Wp are connected in common.

[0025] The positive terminal of the primary DC power supply 32p is connected to a common connection point of the U-phase winding 28Up, the V-phase winding 28Vp, and the W-phase winding 28Wp, and the negative terminal of the primary DC power supply 32p is connected to the lower end of each switching arm.

[0026] The primary controller 14 controls the switching of the upper switching element S1 and the lower switching element S2 of each switching arm. The upper switching element S1 and the lower switching element S2 of each switching arm are alternately turned on and off under the control of the primary controller 14. That is, when the upper switching element S1 changes from off to on, the lower switching element S2 changes from on to off, and when the upper switching element S1 changes from on to off, the lower switching element S2 changes from off to on.

[0027] The U-phase switching arm U, the V-phase switching arm V, and the W-phase switching arm W have different switching phases. For example, the switching phase of the V-phase switching arm V may lag behind the U-phase switching arm U by 60° to 120°, and the switching phase of the W-phase switching arm W may lag behind the V-phase switching arm V by 60° to 120°.

[0028] Switching of the U-phase switching arm U, the V-phase switching arm V, and the W-phase switching arm W generates induced electromotive forces in the U-phase winding 28Up, the V-phase winding 28Vp, and the W-phase winding 28Wp, respectively. A voltage that is a combination of the output voltage of the primary DC power supply 32p and the induced electromotive forces generated in the windings of each phase is applied to the capacitor Ca, charging it.

[0029] U-phase winding 28Up, V-phase winding 28Vp, and W-phase winding 28Wp provided in primary connector 30p are respectively coupled to U-phase winding 28Us, V-phase winding 28Vs, and W-phase winding 28Ws provided in secondary connector 30s. By switching each switching arm provided in primary switching circuit 12, AC current flows through U-phase winding 28Up, V-phase winding 28Vp, and W-phase winding 28Wp, respectively, and induced electromotive forces are generated in U-phase winding 28Us, V-phase winding 28Vs, and W-phase winding 28Ws.

[0030] The secondary power conversion device 20 includes a secondary switching circuit 22, a secondary connector 30s, a secondary DC power supply 32s, a secondary signal transmission circuit 26, and a secondary controller 24. The secondary power conversion device 20 has the same configuration as the primary power conversion device 10. That is, the secondary switching circuit 22, the secondary connector 30s, the secondary DC power supply 32s, the secondary signal transmission circuit 26, and the secondary controller 24 have the same configuration as the primary switching circuit 12, the primary connector 30p, the primary DC power supply 32p, the primary signal transmission circuit 16, and the primary controller 14, respectively, and operate in the same manner.

[0031] The switching of each switching arm of the secondary switching circuit 22 converts the induced electromotive forces generated in the U-phase winding 28Us, the V-phase winding 28Vs, and the W-phase winding 28Ws into DC voltages. This DC voltage is applied to the capacitor Ca of the secondary switching circuit 22, which charges the capacitor Ca. The switching of each switching arm of the secondary switching circuit 22 also generates induced electromotive forces in the U-phase winding 28Us, the V-phase winding 28Vs, and the W-phase winding 28Ws. A voltage that is the sum of the output voltage of the secondary DC power supply 32s and the induced electromotive forces generated in the windings of each phase is applied to the secondary DC power supply 32s. Through this operation, power is transmitted from the capacitor Ca to the secondary power conversion device 20 via the primary connector 30p and the secondary connector 30s.

[0032] The above describes the operation in which power is transmitted from the primary power conversion device 10 to the secondary power conversion device 20 via the primary connector 30p and the secondary connector 30s. By adjusting the switching timing of the primary switching circuit 12 and the switching timing of the secondary switching circuit 22, power can also be transmitted in the opposite direction.

[0033] The primary connector 30p has a U-phase winding 28Up, a V-phase winding 28Vp, a W-phase winding 28Wp, and a signal winding 28gp, and the secondary connector 30s has a U-phase winding 28Us, a V-phase winding 28Vs, a W-phase winding 28Ws, and a signal winding 28gs. When the primary connector 30p and the secondary connector 30s are brought close to each other, the signal windings 28gp and 28gs are coupled.

[0034] Both ends of the signal winding 28gp are connected to the primary signal transmission circuit 16, and both ends of the signal winding 28gs are connected to the secondary signal transmission circuit 26. The primary signal transmission circuit 16 transmits a downstream timing signal to the secondary signal transmission circuit 26 via the signal winding 28gp and the signal winding 28gs under the control of the primary controller 14. The downstream timing signal is a signal that defines the switching timing of the secondary switching circuit 22. The secondary controller 24 controls the switching of the secondary switching circuit 22 according to the timing indicated by the downstream timing signal received by the secondary signal transmission circuit 26. This synchronizes the switching timing of the primary switching circuit 12 and the secondary switching circuit 22.

[0035] The secondary signal transmission circuit 26 may transmit an upstream timing signal to the primary signal transmission circuit 16 via the signal winding 28gs and the signal winding 28gp under the control of the secondary controller 24. The upstream timing signal is a signal that defines the switching timing of the primary switching circuit 12. The primary controller 14 controls the switching of the primary switching circuit 12 according to the timing indicated by the upstream timing signal received by the primary signal transmission circuit 16.

[0036] FIG. 2A shows a perspective view of the primary connector 30p. FIG. 2B shows a perspective view of a core unit 36p of the primary connector 30p. FIG. 2C shows perspective views of the U-phase winding 28Up, the V-phase winding 28Vp, and the W-phase winding 28Wp. As shown in FIG. 2B, the core unit 36p is composed of a generally disk-shaped common core Ep extending along the xy plane, four columnar cores Ap to Dp protruding from the common core Ep in the positive direction of the z-axis, and a neutral columnar core Np protruding from the center of the common core Ep in the positive direction of the z-axis.

[0037] Each of the columnar cores Ap to Dp has a shape obtained by dividing a cylindrical shape with a cylindrical hole in the center into four sections at 90° intervals along a plane including the central axis of the cylindrical shape. The columnar cores Ap to Dp are arranged in this order clockwise in Figure 2A. A neutral columnar core Np is arranged in the region surrounded by the columnar cores Ap to Dp.

[0038] 2C , the W-phase winding 28Wp winds around the columnar cores Ap and Bp in the forward direction to bundle the columnar cores Ap and Bp, and winds around the columnar cores Dp and Cp in the reverse direction to bundle the columnar cores Dp and Cp. Note that the terms "forward direction" and "reverse direction" are relative terms indicating that the direction of winding around the columnar cores Ap and Bp is opposite to the direction of winding around the columnar cores Dp and Cp, and do not indicate absolute winding directions.

[0039] The W-phase winding 28Wp may wind around the columnar cores Ap and Bp multiple times in the positive direction, and then wind around the columnar cores Dp and Cp multiple times in the negative direction. Alternatively, the W-phase winding 28Wp may wind around the columnar cores Ap and Bp once in the positive direction, and then wind around the columnar cores Dp and Cp once in the negative direction, repeating this figure-of-eight winding multiple times around the columnar cores Ap-Dp.

[0040] The U-phase winding 28Up is disposed closer to the common core Ep than the W-phase winding 28Wp. The U-phase winding 28Up is disposed on the columnar cores Ap and Bp so as to wind around the columnar core Bp in the forward direction and then wind around the columnar core Ap in the reverse direction. The U-phase winding 28Up may first wind around the columnar core Bp multiple times in the forward direction, and then wind around the columnar core Ap multiple times in the negative direction. Alternatively, the U-phase winding 28Up may wind around the columnar cores Ap and Bp in a figure-of-eight pattern multiple times, such as winding around the columnar core Bp once in the forward direction and then winding around the columnar core Ap once in the negative direction.

[0041] The V-phase winding 28Vp is also disposed closer to the common core than the W-phase winding p. The V-phase winding 28Vp is disposed on the columnar cores Cp and Dp so as to wind around the columnar core Dp in the forward direction and then wind around the columnar core Cp in the reverse direction. The V-phase winding 28Vp may first wind around the columnar core Dp multiple times in the forward direction, and then wind around the columnar core Cp multiple times in the negative direction. Alternatively, the V-phase winding 28Vp may wind around the columnar cores Cp and Dp in a figure-of-eight pattern multiple times, such as winding around the columnar core Dp once in the forward direction and then winding around the columnar core Cp once in the negative direction.

[0042] The magnetic flux generated in the section of the W-phase winding 28Wp that circulates around the columnar cores Ap and Bp interlinks with the section A of the U-phase winding 28Up that circulates around the columnar core Ap and the section B of the U-phase winding 28Up that circulates around the columnar core Bp. This generates induced electromotive forces in the sections A and B. However, the U-phase winding 28Up circulates in the opposite directions in the sections A and B. Therefore, the induced electromotive forces generated in the sections A and B subtract from each other, and the induced electromotive forces output from both ends of the U-phase winding 28Up are small or zero. Furthermore, the magnetic flux generated in the section A that interlinks with the W-phase winding 28Wp and the magnetic flux generated in the section B that interlinks with the W-phase winding 28Wp are oriented in opposite directions. Therefore, the induced electromotive forces generated in the W-phase winding 28Wp based on the magnetic flux generated in the sections A and B of the U-phase winding 28Up are small or zero.

[0043] The magnetic flux generated in the section of the W-phase winding 28Wp that circulates around the columnar cores Cp and Dp interlinks with the section C of the V-phase winding 28Vp that circulates around the columnar core Cp and the section D of the V-phase winding 28Vp that circulates around the columnar core Dp. This generates an induced electromotive force in the sections C and C. However, the V-phase winding 28Vp circulates in the opposite directions in the sections C and D. Therefore, the induced electromotive forces generated in the sections C and D subtract from each other, and the induced electromotive force output from both ends of the V-phase winding 28Vp is minimal or zero. Furthermore, the magnetic flux generated in the section C that interlinks with the W-phase winding 28Wp and the magnetic flux generated in the section D that interlinks with the W-phase winding 28Wp are oriented in opposite directions. Therefore, the induced electromotive force generated in the W-phase winding 28Wp based on the magnetic flux generated in the sections C and D of the V-phase winding 28Vp is minimal or zero.

[0044] In this way, the U-phase winding 28Up, the V-phase winding 28Vp, and the W-phase winding 28Wp are in a non-interfering relationship with one another. That is, they do not mutually induce electromotive forces, or the induced electromotive forces they mutually generate are very small. More specifically, when a magnetic flux generated from one of the windings interlinks with the other two windings, the induced electromotive forces generated in the other two windings are very small or zero.

[0045] A signal winding 28gp is wound around the neutral columnar core Np. The influence of the magnetic flux generated by the signal winding 28gp on the other windings will be described later.

[0046] FIG. 3 shows a perspective view of the secondary connector 30s. Each component of the secondary connector 30s is assigned a reference numeral with the letter "p" at the end of the reference numeral of the corresponding component in the primary connector 30p replaced with an "s." The structure of the secondary connector 30s is a mirror image of the structure of the primary connector 30p shown in FIGS. 2A to 2C. In the secondary connector 30s, the winding direction of all windings may be reversed for the structure that is a mirror image of the structure of the primary connector 30p. The same applies to the windings provided in each secondary connector described below.

[0047] The primary connector 30p and the secondary connector 30s are arranged so that the tip faces of the columnar cores Ap-Dp of the primary connector 30p face the tip faces of the columnar cores As-Ds of the secondary connector 30s without contacting each other. As a result, the U-phase winding 28Up, the V-phase winding 28Vp, and the W-phase winding 28Wp of the primary connector 30p are coupled to the U-phase winding 28Us, the V-phase winding 28Vs, and the W-phase winding 28Ws of the secondary connector 30s, respectively, thereby forming a decoupling transformer. In other words, a decoupling transformer is formed in which the primary connector 30p serves as the primary-side transformer winding structure (connector winding structure) and the secondary connector 30s serves as the secondary-side transformer winding structure (connector winding structure).

[0048] The primary connector 30p and the secondary connector 30s form a decoupling transformer, which prevents the power transmission operations of the U phase, V phase, and W phase from affecting each other, thereby ensuring reliable control of each phase of the primary switching circuit 12 and the secondary switching circuit 22.

[0049] Thus, the transformer winding structure formed by the primary connector 30p includes a plurality of columnar cores Ap, Bp, Cp, and Dp arranged with the same extension direction, a neutral columnar core Np, a U-phase winding 28Up, a V-phase winding 28Vp, and a W-phase winding 28Wp as multi-phase power windings, and a signal winding 28gp.

[0050] The multiple columnar cores Ap, Bp, Cp, and Dp are arranged in a circumferential pattern within a plane intersecting their respective extension directions (z-axis direction), and one end is connected to the common core Ep. The neutral columnar core Np is arranged in a position surrounded by the multiple columnar cores, with its extension direction aligned with each columnar core, and one end is connected to the common core Ep. The multiple-phase power windings are provided on the multiple columnar cores so that the magnetic flux linking between them is subtracted. The signal winding 28gp is provided on the neutral columnar core Np. The transformer winding structure formed by the secondary connector 30s is a mirror image of the transformer winding structure formed by the primary connector 30p. For the secondary connector 30s, the winding direction of all windings may be reversed in the mirror image structure of the primary connector 30p.

[0051] Figure 4 shows a schematic cross section of a decoupling transformer cut along a plane including the cylindrical cores Ap, Cp, and Np, as well as the cylindrical cores As, Cs, and Ns. The black dots on the cross section of each winding indicate that the current flows away from the drawing surface. The "x" shapes on the cross section of each winding indicate that the current flows toward the drawing surface.

[0052] In the W-phase winding 28Wp of the primary connector 30p, the magnetic flux ΦAB generated from the section AB that circulates around the cylindrical cores Ap and Bp passes from the cylindrical core Ap through the common core Ep toward the cylindrical core Cp and the neutral cylindrical core Np. The magnetic flux AB that passes through the cylindrical core Cp then passes through the cylindrical core Cs toward the common core Es, and the magnetic flux AB that passes through the neutral cylindrical core Np passes through the neutral cylindrical core Ns toward the common core Es.

[0053] In the W-phase winding 28Wp of the primary connector 30p, the magnetic flux ΦCD generated from the CD section circulating around the cylindrical cores Cp and Dp flows from the cylindrical core Cp to the cylindrical core Cs. The magnetic flux ΦCD passing through the cylindrical core Cs passes through the common core Es and flows toward the cylindrical core As and the neutral cylindrical core Ns. The magnetic flux ΦCD passing through the neutral cylindrical core Ns also passes through the neutral cylindrical core Np and flows toward the common core Ep.

[0054] The magnetic flux ΦAB, which is generated from section AB of the W-phase winding 28Wp and passes through the neutral cores Np and Ns, and the magnetic flux ΦCD, which is generated from section CD of the W-phase winding 28Wp and passes through the neutral cores Ns and Np, are in opposite directions and suppress each other. Therefore, the induced electromotive force generated in the signal windings 28gp and 28gs by the magnetic flux generated from the W-phase winding 28Wp is zero or is very small.

[0055] FIG. 5 shows the magnetic flux Φg emanating from the signal winding 28gp in the same cross section as FIG. 4. The magnetic flux Φg passes through the neutral columnar core Np and the neutral columnar core Ns toward the common core Es. The magnetic flux Φg passes from the common core Es toward the columnar core As and the columnar core Cs. The magnetic flux Φg passing through the columnar core As further passes through the columnar core Ap, and the magnetic flux Φg passing through the columnar core Cs further passes through the columnar core Cp. As shown in FIG. 5, the magnetic flux Φg passes downward through the columnar cores As and Ap and then downward through the columnar cores Cs and Cp. In other words, the direction of the magnetic flux passing through the columnar cores As and Ap is the same as the direction of the magnetic flux passing through the columnar cores Cs and Cp.

[0056] The winding directions are opposite in sections AB and CD of W-phase winding 28Wp and W-phase winding 28Ws. Therefore, the induced electromotive force generated in section AB of W-phase winding 28Wp by magnetic flux Φg and the induced electromotive force generated in section CD of W-phase winding 28Wp by magnetic flux Φg have opposite polarities and suppress each other, resulting in zero or very small induced electromotive force in W-phase winding 28Wp. Similarly, the induced electromotive force generated in section AB of W-phase winding 28Ws by magnetic flux Φg and the induced electromotive force generated in section CD of W-phase winding 28Ws by magnetic flux Φg have opposite polarities and suppress each other, resulting in zero or very small induced electromotive force in W-phase winding 28Ws.

[0057] In this way, in the transformer winding structure formed by the primary connector 30p, a neutral magnetic path is formed that passes through the neutral columnar core 28Np and each of the columnar cores Ap to Dp. As a result, the U-phase winding 28Up, V-phase winding 28Vp, and W-phase winding Wp do not interfere with each other, and the induced electromotive forces generated between them are zero or very small. Similarly, in the transformer winding structure formed by the secondary connector 30s, a neutral magnetic path is formed that passes through the neutral columnar core 28Ns and each of the columnar cores As to Ds. As a result, the induced electromotive forces generated between the U-phase winding 28Us, V-phase winding 28Vs, and W-phase winding Ws and the signal winding 28gs are zero or very small.

[0058] Although the case where magnetic flux is generated on the primary connector 30p side has been described above, the same applies to the case where magnetic flux is generated on the secondary connector 30s side. This is because the secondary connector 30s has a structure that is a mirror image of the primary connector 30p, or a structure in which the winding directions of all the windings are reversed from that of the primary connector 30p.

[0059] That is, the magnetic flux generated from each power winding (U-phase winding 28Up, V-phase winding 28Vp, W-phase winding 28Wp, U-phase winding 28Us, V-phase winding 28Vs, and W-phase winding 28Ws) mainly passes through the columnar cores Ap-Dp and As-Ds, and does not pass through the neutral columnar cores Np and Ns. The magnetic flux generated from the signal windings 28gp and 28gs passes through the columnar cores surrounded by each power winding in the same direction.

[0060] Therefore, the W-phase windings 28Wp and 28Ws do not generate induced electromotive forces, and the signal winding 28gp does not generate induced electromotive forces, or the induced electromotive forces that they generate are very small, and they are in a non-interfering relationship. By the same principle, the U-phase windings 28Up and 28Us do not interfere with the signal winding 26gp, and the V-phase windings 28Vp and 28Vs do not interfere with the signal winding 28gp.

[0061] Returning to Figure 1, the control of the primary switching circuit 12 and the secondary switching circuit 22 will now be described. The primary signal transmission circuit 16 outputs a downstream timing signal to the signal winding 28gp in accordance with the control of the primary controller 14. The downstream timing signal is a signal in which a pulsed time waveform is repeated on the time axis. The pulsed time waveform indicated by the downstream timing signal indicates the timing at which the primary controller 14 switches the primary switching circuit 12. The signal winding 28gp and the signal winding 28gs are coupled, and the downstream timing signal is transmitted to the secondary signal transmission circuit 26 via the signal winding 28gp and the signal winding 28gs.

[0062] The secondary signal transmission circuit 26 detects the downstream timing signal and outputs it to the secondary controller 24. The secondary controller 24 switches the secondary switching circuit 22 in accordance with the timing indicated by the downstream timing signal.

[0063] The secondary signal transmission circuit 26 outputs an upward timing signal to the signal winding 28gs under the control of the secondary controller 24. The upward timing signal is a signal in which a pulse-like time waveform is repeated on the time axis. The pulse-like time waveform indicated by the upward timing signal indicates the timing at which the secondary controller 24 switches the secondary switching circuit 22. The upward timing signal is transmitted to the primary signal transmission circuit 16 via the signal windings 28gs and 28gp.

[0064] The primary signal transmission circuit 16 detects the upstream timing signal and outputs it to the primary controller 14. The primary controller 14 switches the primary switching circuit 12 according to the timing indicated by the upstream timing signal. Through this operation, the switching timing of the primary switching circuit 12 and the secondary switching circuit 22 is synchronized.

[0065] As described above, the U-phase winding 28Up, V-phase winding 28Vp, and W-phase winding 28Wp in the primary connector 30p do not interfere with the signal winding 28gp. Similarly, the U-phase winding 28Us, V-phase winding 28Vs, and W-phase winding 28Ws in the secondary connector 30s do not interfere with the signal winding 28gs. This reduces interference between the voltages and currents appearing in the windings of each phase and the down- or up-timing signal. This ensures reliable control of the primary switching circuit 12 and the secondary switching circuit 22.

[0066] The primary signal transmission circuit 16 receives an upstream timing signal from the signal winding 28gp. The primary controller 14 operates as a connector disconnection detection device that detects a loose connection between the primary connector 30p (transformer winding structure) and the secondary connector 30s (another winding structure) based on the level of the upstream timing signal. The primary controller 14 also has the function of stopping the switching of the primary switching circuit 12 when it detects that the connection between the primary connector 30p and the secondary connector 30s has loosened.

[0067] Similarly, the secondary signal transmission circuit 26 receives a downstream timing signal from the signal winding 28gs. The secondary controller 24 operates as a connector disconnection detection device that detects a loose connection between the primary connector 30p (transformer winding structure) and the secondary connector 30s (another winding structure) based on the level of the downstream timing signal. The secondary controller 24 also has the function of stopping the switching of the secondary switching circuit 22 when it detects that the connection between the primary connector 30p and the secondary connector 30s has loosened.

[0068] That is, the secondary controller 24 determines whether the level of the down timing signal is equal to or lower than a predetermined threshold, and if the level of the down timing signal is equal to or lower than the predetermined threshold, stops the switching of the secondary switching circuit 22. Similarly, the primary controller 14 determines whether the level of the up timing signal is equal to or lower than a predetermined threshold, and if the level of the up timing signal is equal to or lower than the predetermined threshold, stops the switching of the primary switching circuit 12.

[0069] By this processing, when a connector disconnection (a state of loose coupling) occurs, such as when the secondary connector 30s is disconnected from the primary connector 30p or when the position of the secondary connector 30s relative to the primary connector 30p is shifted from the appropriate position, the switching operation of the primary switching circuit 12 and the secondary switching circuit 22 is stopped.

[0070] Figure 6(a) conceptually shows the relationship between the distance between the primary connector 30p and the secondary connector 30s (connector distance) and the coupling coefficient. The horizontal axis represents the connector distance, and the vertical axis represents the coupling coefficient. The coupling coefficient represents the degree of coupling between the U-phase winding 28Up and the U-phase winding 28Us, the degree of coupling between the V-phase winding 28Vp and the V-phase winding 28Vs, or the degree of coupling between the W-phase winding 28Wp and the W-phase winding 28Ws. The coupling coefficient k between two windings is defined as k = M / √(L1 L2), where L1 is the inductance of one winding, L2 is the inductance of the other winding, and M is the mutual inductance between these windings.

[0071] 6(b) to 6(f) show control timing charts for the primary switching circuit 12 and the secondary switching circuit 22. The horizontal axis in each diagram represents time. FIG. 6(b) shows an initial trigger signal used inside the primary controller 14. The initial trigger signal indicates the timing at which switching of the primary switching circuit 12 begins. FIG. 6(c) shows a switching control signal for the primary switching circuit 12. With the rising edge of the switching control signal, for example, the upper switching element S1 of the U-phase switching arm U of the primary switching circuit 12 may be switched on and off, and the lower switching element S2 may be switched off and on.

[0072] Figure 6(d) shows the voltage between the terminals of the signal winding 28gp (primary signal winding voltage). In the primary signal winding voltage, a down timing signal and an up timing signal appear alternately over time. The down timing signal is synchronized with the switching control signal for the primary switching circuit 12 (Figure 6(c)). The up timing signal appearing in the primary signal winding voltage has a smaller amplitude than the down timing signal. The upper right corner of Figure 6(d) shows the time waveform of the down timing signal when the time axis scale is expanded. One pulse of the down timing signal has a time waveform in which a sine wave attenuates over time and converges to zero.

[0073] Figure 6(e) shows the voltage between the terminals of the signal winding 28gs (secondary signal winding voltage). In the secondary signal winding voltage, rising timing signals and falling timing signals appear alternately over time. The falling timing signals appearing in the secondary signal winding voltage have a smaller amplitude than the rising timing signals. The time waveform of the falling timing signal is shown in the upper right of Figure 6(e). The time waveform on the right is a time waveform when the distance between the primary connector 30p and the secondary connector 30s is greater than that on the left.

[0074] 6(f) shows the switching control signal of the secondary switching circuit 22. This switching control signal is synchronized with the falling timing signal. When a predetermined time has elapsed since the rising edge of the switching control signal, for example, the upper switching element S1 of the U-phase switching arm U of the secondary switching circuit 22 may be switched on / off and the lower switching element S2 may be switched off / on.

[0075] The greater the distance between the connectors, the smaller the coupling coefficient. This reduces the amplitude of the upstream timing signal detected by the primary signal transmission circuit 16, and the amplitude of the downstream timing signal detected by the secondary signal transmission circuit 26. Therefore, as described above, the primary controller 14 may detect a connector disconnection in accordance with the level (amplitude) of the upstream timing signal detected by the primary signal transmission circuit 16. Similarly, the secondary controller 24 may detect a connector disconnection in accordance with the level (amplitude) of the downstream timing signal detected by the secondary signal transmission circuit 26.

[0076] The primary controller 14 may also store a table that associates the level of the upstream timing signal with the distance between the connectors. The level of the upstream timing signal is defined, for example, as the maximum absolute value. The primary controller 14 may refer to the table and obtain the distance corresponding to the level of the upstream timing signal to determine the distance between the connectors. Similarly, the secondary controller 24 may store a table that associates the level of the downstream timing signal with the distance between the connectors. The level of the downstream timing signal is defined, for example, as the maximum absolute value. The secondary controller 24 may refer to the table and obtain the distance corresponding to the level of the downstream timing signal to determine the distance between the connectors.

[0077] 7 shows a first configuration example of the primary signal transmission circuit 16-1 and the secondary signal transmission circuit 26-1. The primary signal transmission circuit 16-1 includes a DC power supply 42p, a switching arm Xp, and a resonant capacitor 40p. The switching arm Xp includes an upper switching element Q1 and a lower switching element Q2 connected in series.

[0078] The lower end of the lower switching element Q2 is connected to the negative electrode of the DC power supply 42p. The upper end of the upper switching element Q1 is connected to the positive electrode of the DC power supply 42p. One end of a resonant capacitor 40p is connected to the connection point between the upper switching element Q1 and the lower switching element Q2 of the switching arm Xp, and the other end of the resonant capacitor 40p is connected to one end of a signal winding 28gp. The other end of the signal winding 28gp is connected to the lower end of the lower switching element Q2.

[0079] The secondary signal transmission circuit 26-1 includes a DC power supply 42s, a switching arm Xs, and a resonant capacitor 40s. The secondary signal transmission circuit 26-1 has a configuration similar to that of the primary signal transmission circuit 16-1. The DC power supply 42s, the switching arm Xs, and the resonant capacitor 40s correspond to the DC power supply 42p, the switching arm Xp, and the resonant capacitor 40p, respectively. One end of the resonant capacitor 40s is connected to the connection point between the upper switching element Q1 and the lower switching element Q2 of the switching arm Xs, and the other end of the resonant capacitor 40s is connected to one end of the signal winding 28gs. The other end of the signal winding 28gs is connected to the lower end of the lower switching element Q2.

[0080] The operation of transmitting a downstream signal from the primary signal transmission circuit 16-1 will be described. The upper switching element Q1 and the lower switching element Q2 of the switching arm Xp are alternately turned on and off. Each time the upper switching element Q1 and the lower switching element Q2 are switched on and off, a pulse voltage is applied to a series resonant circuit formed by the resonant capacitor 40p and the signal winding 28gp. Each time the pulse voltage is applied, a current having an oscillating waveform flows through the series resonant circuit. The series resonant circuit causes the voltage generated in the signal winding 28gp to oscillate in a damped manner. In other words, the series resonant circuit forms a damped oscillation circuit, and the oscillating waveform of the voltage generated in the signal winding 28gp is attenuated by the resistance components included in the upper switching element Q1 or the lower switching element Q2 and the resistance components included in the signal winding 28gp, resulting in a damped oscillation waveform.

[0081] The current flowing through the signal winding 28gp generates an induced electromotive force with a damped oscillatory waveform in the signal winding 28gs. A signal detector 44s provided in the signal winding 28gs detects the induced electromotive force generated in the signal winding 28gs as a downward timing signal and outputs it to the secondary controller 24.

[0082] The operation of transmitting an upstream signal from the secondary signal transmission circuit 26-1 will now be described. The upper switching element Q1 and the lower switching element Q2 of the switching arm Xs are alternately turned on and off. Each time the upper switching element Q1 and the lower switching element Q2 are switched on and off, a pulse voltage is applied to the series resonant circuit formed by the resonant capacitor 40s and the signal winding 28gs. Using the same principle as on the primary side, each time a pulse voltage is applied, a current having a damped oscillatory waveform flows in the series resonant circuit.

[0083] The current flowing through the signal winding 28gs generates an induced electromotive force with a damped oscillatory waveform in the signal winding 28gp. The signal detector 44p provided in the signal winding 28gp detects the induced electromotive force generated in the signal winding 28gp as an ascending timing signal and outputs it to the primary controller 14.

[0084] Note that the primary signal transmission circuit 16-1 and the secondary signal transmission circuit 26-1 may each use two parallel-connected switching arms instead of the switching arms Xp and Xs. Fig. 8 shows a primary signal transmission circuit 16-2 and a secondary signal transmission circuit 26-2 according to a second configuration example. As shown in Fig. 8, a series resonant circuit including a resonant capacitor 40p and a signal winding 28gp is connected between the switching element connection point of one switching arm Xp and the switching element connection point of the other switching arm Yp in the primary signal transmission circuit 16-1. Similarly, a series resonant circuit including a resonant capacitor 40s and a signal winding 28gs is connected between the switching element connection point of one switching arm Xs and the switching element connection point of the other switching arm Ys in the secondary signal transmission circuit 26-2.

[0085] When the upper switching element Q1 of the switching arm Xp is on and the lower switching element Q2 of the switching arm Xp is off, the upper switching element Q1 of the switching arm Yp is off and the lower switching element Q2 of the switching arm Yp is on. When the upper switching element Q1 of the switching arm Xp is off and the lower switching element Q2 of the switching arm Yp is on and the lower switching element Q2 of the switching arm Yp is off.

[0086] Similarly, when the upper switching element Q1 of the switching arm Xs is on and the lower switching element Q2 of the switching arm Xs is off, the upper switching element Q1 of the switching arm Ys is off and the lower switching element Q2 of the switching arm Ys is on. When the upper switching element Q1 of the switching arm Xs is off and the lower switching element Q2 of the switching arm Ys is on and the lower switching element Q2 of the switching arm Ys is off.

[0087] 9 shows a primary signal transmission circuit 16-3 and a secondary signal transmission circuit 26-3 according to a third configuration example. The primary signal transmission circuit 16-3 corresponds to the primary signal transmission circuit 16-1 shown in FIG. 7 in which the lower switching element Q2 of the switching arm Xp is removed and set to an open state, and a discharge resistor Rp is connected in parallel to the resonant capacitor 40p. The secondary signal transmission circuit 26-3 corresponds to the secondary signal transmission circuit 26-1 shown in FIG. 7 in which the lower switching element Q2 of the switching arm Xp is removed and set to an open state, and a discharge resistor Rs is connected in parallel to the resonant capacitor 40s.

[0088] The operation of transmitting a downstream signal from the primary signal transmission circuit 16-3 will be described. Each time the switching element Qp is turned on for a predetermined pulse time length, a pulse voltage is applied to the series resonant circuit formed by the resonant capacitor 40p and the signal winding 28gp. Each time the pulse voltage is applied, a current having an oscillating waveform flows through the series resonant circuit. This oscillating waveform becomes a damped oscillating waveform due to the resistance components included in the switching element Qp and the signal winding 28p. When the switching element Qp is turned off, the charge stored in the resonant capacitor 40p is discharged to the discharge resistor Rp.

[0089] The current flowing through the signal winding 28gp generates an induced electromotive force with a damped oscillatory waveform in the signal winding 28gs. A signal detector 44s provided in the signal winding 28gs detects the induced electromotive force generated in the signal winding 28gs as a downward timing signal and outputs it to the secondary controller 24.

[0090] The operation of transmitting an upstream signal from the secondary signal transmission circuit 26-3 will now be described. Each time the switching element Qs is turned on for a predetermined pulse time, a pulse voltage is applied to the series resonant circuit formed by the resonant capacitor 40s and the signal winding 28gs. Using the same principle as on the primary side, each time a pulse voltage is applied, a current having a damped oscillatory waveform flows through the series resonant circuit. When the switching element Qs is turned off, the charge stored in the resonant capacitor 40s is discharged to the discharge resistor Rs.

[0091] The current flowing through the signal winding 28gs generates an induced electromotive force with a damped oscillatory waveform in the signal winding 28gp. The signal detector 44p provided in the signal winding 28gp detects the induced electromotive force generated in the signal winding 28gp as an ascending timing signal and outputs it to the primary controller 14.

[0092] In the above, an embodiment has been described in which the primary connector 30p and the secondary connector 30s each have three-phase power windings (U, V, and W phases) and one signal winding. Each of the primary connector and the secondary connector may have power windings for more than three phases. More generally, each of the primary connector and the secondary connector may have 2M-1-phase power windings and one signal winding, where M is an integer greater than or equal to 2.

[0093] FIG. 10 shows a primary connector 50p equipped with five power windings and one signal winding. The structure of the secondary connector corresponding to the primary connector 50p is a mirror image of the structure shown in FIG. 10. The secondary connector may have a mirror image of the structure of the primary connector 50p, with all windings having the reversed winding direction. The primary connector 50p includes a-phase windings 28a through 28e, a signal winding 28S, columnar cores 1 through 6, and a neutral columnar core Np. The columnar cores 1 through 6 and the neutral columnar core Np are joined to a common core (not shown) at their far ends as viewed from the drawing surface. The columnar cores 1 through 6 are arranged clockwise in this order in FIG. 10. The a-phase winding 28a is wound in a figure-eight pattern around columnar cores 1 and 2. The b-phase winding 28b is wound in a figure-eight pattern around columnar cores 4 and 5. The c-phase winding 28c ties together the columnar cores 1 and 2 and forms an eight-shaped loop around the columnar core 6. The d-phase winding 28d ties together the columnar cores 4 and 5 and forms an eight-shaped loop around the columnar core 3. The e-phase winding 28e ties together the columnar cores 2, 1, and 6 and forms an eight-shaped loop around the columnar cores 3, 4, and 5.

[0094] FIG. 11 shows a primary connector 52p equipped with seven power windings and one signal winding. The secondary connector corresponding to the primary connector 52p has a structure that is a mirror image of the structure shown in FIG. 11. The secondary connector may have a structure that is a mirror image of the primary connector 52p, with all windings having the reversed winding direction. The primary connector 52 has a-phase windings 28a to 28g, a signal winding 28S, columnar cores 1 to 8, and a neutral columnar core Np. The columnar cores 1 to 8 and the neutral columnar core Np are joined to a common core (not shown) at their ends on the far side of the drawing. The columnar cores 1 to 8 are arranged in this order clockwise in FIG. 10.

[0095] The a-phase winding 28, the b-phase winding 28b, the c-phase winding 28c, and the d-phase winding 28d are wound in a figure-8 shape around the columnar cores 1 and 2, the columnar cores 3 and 4, the columnar cores 5 and 6, and the columnar cores 7 and 8, respectively. The e-phase winding 28e forms a figure-8 loop that ties together the columnar cores 1 and 2 and the columnar cores 3 and 4. The f-phase winding 28f forms a figure-8 loop that ties together the columnar cores 5 and 6 and the columnar cores 7 and 8. The g-phase winding 28g forms a figure-8 loop that ties together the columnar cores 1 to 4 and the columnar cores 5 to 8.

[0096] 10 and 11, similar to the structure shown in FIG. 2A, magnetic flux emanating from one of the two loops forming a figure eight in one power winding either does not link with either of the two loops forming a figure eight in the other power winding, or it links with both loops forming a figure eight in the other power winding. If magnetic flux emanating from one of the two loops forming a figure eight links with both loops forming a figure eight in the other power winding, an induced electromotive force of opposite polarity is generated in the two loops in the other power winding. As a result, the induced electromotive force generated between the terminals of the other power winding is suppressed.

[0097] When the magnetic flux emitted from one of the two loops forming a figure eight in one power winding interlinks with two loops forming a figure eight in the other power winding, one power winding is defined as the upper winding and the other power winding is defined as the lower winding. The magnetic flux emitted from one of the two loops forming a figure eight in the lower winding does not interlink with either of the two loops forming a figure eight in the upper winding.

[0098] 10 and 11, the loops in one of the multiple-phase power windings, that is, the upper winding, surround the magnetic flux generated from the figure-eight-shaped loops in the other of the multiple-phase power windings, that is, the lower winding. Therefore, in the connector having the structure shown in FIGS. 10 and 11, the multiple-phase power windings do not interfere with each other.

[0099] Furthermore, the magnetic flux emitted from signal winding 28S interlinks with both of the two loops forming a figure-8 in each power winding. Because induced electromotive forces of opposite polarity are generated in the two loops of each power winding, the magnetic flux emitted from signal winding 28S suppresses the induced electromotive forces generated between the terminals of each power winding. This results in a non-interference relationship between the signal winding and each power winding. [Explanation of symbols]

[0100] 1 to 8 columnar core, 10 primary power converter, 12 primary switching circuit, 14 primary controller, 16, 16-1, 16-2, 16-3 primary transmission circuit, 20 secondary power converter, 22 secondary switching circuit, 24 secondary controller, 26-1, 26-2, 26-3 secondary transmission circuit, 28Up, 28Us U-phase winding, 28Vp, 28Vs V-phase winding, 28Wp, 28Ws W-phase winding, 28a to 28g a-phase winding to g-phase winding, 28gp, 28gs, 28S signal winding, 30p, 50p, 52p primary connector, 30s secondary connector, 32p primary DC power supply, 32s secondary DC power supply, 36p, 36s core unit, 40p, 40s resonant capacitor, 42p, 42s DC power supply, 44p, 44s signal detector, UU phase switching arm, VV phase switching arm, WW phase switching arm, Ca capacitor, Ap, Bp, Cp, Dp, As, Bs, Cs, Ds columnar core, Np, Ns neutral columnar core, Ep, Es common core.

Claims

1. a plurality of columnar cores arranged with the same extension direction, the columnar cores being arranged in a circumferential shape in a plane intersecting the extension direction, and one end of the columnar cores being connected to a common core; a neutral columnar core, the neutral columnar core being arranged at a position surrounded by the plurality of columnar cores, with the extension direction aligned with each of the columnar cores, and one end of the neutral columnar core being coupled to the common core; a plurality of power windings of multiple phases provided on the plurality of columnar cores so that magnetic fluxes interlinking with each other are reduced; a signal winding provided on the neutral columnar core.

2. 2. The transformer winding structure of claim 1, A transformer winding structure, characterized in that a neutral magnetic path is formed that passes through the neutral columnar core and passes through each of the columnar cores.

3. 3. The transformer winding structure according to claim 1 or 2, A loop in an upper winding, which is one of the power windings of the multiple phases, A transformer winding structure characterized in that it surrounds magnetic flux generated from an eight-shaped loop in a lower winding, which is another one of the power windings of the plurality of phases.

4. A connector disconnection detection device used for the transformer winding structure according to any one of claims 1 to 3, a switching circuit connected to the power windings of the plurality of phases; a signal transmission circuit connected to the signal winding; a controller that controls the switching circuit and the signal transmission circuit, the signal transmission circuit obtains a timing signal from the signal winding that defines the switching timing of the switching circuit; The controller A connector disconnection detection device that detects a loosening of the coupling between the transformer winding structure and another winding structure based on the level of the timing signal.

5. 5. The connector disconnection detection device according to claim 4, The controller A connector disconnection detection device, characterized in that the distance between the transformer winding structure and the other winding structure is determined based on the level of the timing signal.

6. 6. The connector disconnection detection device according to claim 4 or 5, The signal transmission circuit includes: a damping oscillation circuit for damping oscillation of a voltage generated by the other winding structure in the signal winding;

7. 7. The connector disconnection detection device according to claim 4, The controller When it is detected that the coupling has become loose, the switching operation of the switching circuit is stopped.

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