JP4157545B2 - Transformer element, voltage converter and coil - Google Patents

Description

  The present invention relates to a transformer and a coil having a primary side winding and a secondary side winding, and a voltage converter that generates a DC output voltage from a DC input voltage using such a transformer.

  Conventionally, various DC-DC converters have been proposed and put into practical use as voltage converters. Most of them use a switching circuit connected to the primary winding of the power conversion transformer (transformer element) to switch the DC input voltage and extract the switching output to the secondary winding of the power conversion transformer. is there. With the switching operation of the switching circuit, the voltage appearing in the secondary winding is rectified by the rectifier circuit, then converted to direct current by the smoothing circuit and output.

  In this type of voltage converter, the secondary side of the transformer is generally a so-called center tap type rectification method. FIG. 16 schematically shows the external configuration of the secondary side of a general center tap type rectifying transformer 103. A pair of sheet metal is wound around the protrusion 130 </ b> A of the magnetic core 130 so as to face each other. One end of each of these sheet metals is connected to one end (cathode) of the diodes 104A and 104B as the extraction ends 133A and 133B, respectively, and the other ends are connected in common and connected to the center tap as the extraction end 133C. The rectifier circuit is configured by the diodes 104A and 104B, and the smoothing circuit is configured by the coil 151 and the capacitor 152, so that the DC voltage Vout1 is output.

  For example, Patent Documents 1 and 2 disclose a transformer 203 having an external configuration as shown in FIG. In this case also, the rectifier circuit is configured by the diodes 204A and 204B, the smoothing circuit is configured by the coil 251 and the capacitor 252, and the DC voltage Vout2 is output.

JP 2005-5386 A JP 2000-173839 A

  Here, FIG. 18 and FIG. 19 show the state of current flowing through each end of the sheet metal in the transformers 103 and 203 shown in FIG. 16 and FIG. It is schematically represented by FIGS. 18A and 19A show current states when the diodes 104A and 204A are turned on, and FIGS. 18B and 19B show the current states when the diodes 104B and 204B are turned on. It represents the current state when conducting. In any current state, the lead-out end portion through which the current flows is indicated by hatching.

  In the transformer 103 having the configuration shown in FIG. 16, the lead-out portion of the transformer 103 is divided into two by the extending surface of the sheet metal by the lead-out ends 133A and 133C or the lead-out ends 133B and 133C. In any case of (B), the sectional area of the lead-out end through which the current flows is ½ of the whole lead-out end. On the other hand, in the transformer 203 having the configuration shown in FIG. 17, the lead-out portion of the transformer 203 is divided into three by the extending surface of the sheet metal by the lead-out ends 233A and 233C or the lead-out ends 233B and 233C. ) And (B), the cross-sectional area of the lead-out end through which the current flows is 1/3 of the whole lead-out end.

  Thus, if the wiring width of the lead-out end is narrowed and the cross-sectional area of the portion through which the current flows is small, the wiring resistance of the sheet metal portion is increased. Also, if the wiring resistance is high, the voltage drop at that portion becomes large, making it difficult to flow a large current and increasing the power loss at that portion. Therefore, it is difficult to reduce the wiring resistance in the conventional transformer in which the wiring width of the secondary lead-out portion is narrow.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a transformer element and a coil capable of reducing the wiring resistance of the lead-out portion on the secondary side, and a voltage conversion provided with such a transformer element. To provide an apparatus.

  The transformer element according to the present invention includes a magnetic core, a primary winding wound around the magnetic core, and the first and second lead ends and the center tap lead end wound around the magnetic core. A secondary winding provided on one side of the magnetic core, the secondary winding is wound in one polarity direction with respect to the magnetic core, and one end of the first lead end. A first connecting conductive portion that is wound in the other polarity direction with respect to the magnetic core, one end of the second connecting conductive portion forming the second lead end, and one end of the center. The tap lead-out end is configured, and the other two ends each have a center tap conductive portion connected to the other end of each of the first and second connecting conductive portions on the other side of the magnetic core. .

  A voltage converter according to the present invention includes a switching circuit that switches a DC input voltage to generate an input AC voltage, a transformer element that transforms the input AC voltage and outputs an output AC voltage, and two rectifier elements. A center tap type rectifier circuit that outputs a DC output voltage by rectifying the output AC voltage by these rectifier elements, and a drive circuit that drives the switching circuit. The transformer element includes a magnetic core, A primary winding wound around the magnetic core and supplied with the input AC voltage, and a first winding wound around the magnetic core and connected to one of the two rectifying elements. A first tap end, a second lead end for connecting to another rectifier element, and a center tap lead end for connecting to the center tap of the rectifier circuit are provided on one side of the magnetic core. And A secondary winding from which the output AC voltage is output from between the tap connection end or between the second connection end and the center tap connection end. In contrast, one end is wound in one polarity direction, and one end is wound in the other polarity direction with respect to the first connecting conductive portion constituting the first lead end and the magnetic core, and one end is A second connecting conductive portion constituting the second lead-out end, one end constituting the center tap lead-out end, and the other two ends being the first and second connecting conductive portions on the other side of the magnetic core, respectively. And a center tap conductive portion connected to each other end.

  In the transformer element and the voltage conversion device of the present invention, the other end of each of the first connection conductive portion and the second connection conductive portion is the center tap conductive portion on the other side of the magnetic core different from the extending direction of each lead-out end. Since it is connected to the other two ends, it is not necessary to divide the center tap lead-out end of the center tap conductive portion in the extending surface direction, and it can be constituted by one lead-out end. Therefore, the wiring width of the center tap lead-out end becomes wider than in the conventional case, and the cross-sectional area thereof also increases in comparison with the conventional case.

  In the transformer element of the present invention, it is preferable that one side and the other side of the magnetic core have a positional relationship of 180 ° with the magnetic core as a center. Further, the first and second connecting conductive portions can be configured to intersect each other in a direction orthogonal to the respective extending surfaces. Thus, when comprised so that it may mutually cross | intersect, the 1st and 2nd connection electroconductive part can be isolated, suppressing the installation space of an electroconductive part to the minimum.

  In the transformer element of the present invention, the first and second connecting conductive portions and the center tap conductive portion may be configured as separate members and connected to each other with a screw, or a single member. You may make it comprise from. Thus, when it comprises from a single member, the number of parts of an electroconductive part reduces and management cost also reduces. In this case, these conductive parts can be constituted by plate-like members.

  In the voltage conversion device of the present invention, the two rectifying elements are constituted by the first and second rectifying elements, and the first and second rectifying elements are connected to each one end by screws. Provided independently from each other in a single component having a second screw connection portion, and the first and second lead ends connect the first connection conductive portion or the second connection conductive portion with screws. And the first lead end or the second lead end and the first rectifying element or the second rectifying element are respectively the first and second screw connecting parts. And the pair of screw connection portions are connected to each other with a screw, the distance between the first screw connection portion and the second screw connection portion in the single component, and the first lead-out end And the screw connection portions adjacent to each other at the second extraction end. And intervals preferably configured to be equal to each other. When configured in this way, the number of rectifying elements can be changed by using a plurality of parts having the same configuration, instead of exchanging with parts having different configurations, and the specification can be easily changed.

  The coil of the present invention has a primary winding wound in a predetermined space region, and is wound around the space region, and the first and second lead ends and the center tap lead end are one of the space regions. A secondary winding provided on the side, the secondary winding is wound in one polarity direction with respect to the space region, and one end constitutes the first lead-out end. 1 connection conductive part, and a second connection conductive part, one end of which forms the second extraction end, and one end of the center tap extraction end. The other two ends have center tap conductive portions connected to the other ends of the first and second connection conductive portions on the other side of the space region, respectively.

  In the coil of the present invention, each of the other ends of the first connecting conductive portion and the second connecting conductive portion is connected to the other end of the center tap conductive portion on the other side of a predetermined space region different from the extending direction of each extraction end. Since it is connected to the two ends, there is no need to divide the center tap lead-out end of the center tap conductive portion in the extending surface direction, and it can be constituted by one lead-out end. Therefore, the wiring width of the center tap lead-out end becomes wider than in the conventional case, and the cross-sectional area thereof also increases in comparison with the conventional case.

  According to the transformer element, the voltage conversion device, or the coil of the present invention, the other end of each of the first connection conductive portion and the second connection conductive portion is a magnetic core or a predetermined space different from the extending direction of each extraction end. Since the other end of the region is connected to the other two ends of the center tap conductive portion, the cross-sectional area of the center tap lead-out end increases, and the wiring resistance of the lead-out portion on the secondary side can be reduced. Become.

  Hereinafter, the best mode for carrying out the present invention (hereinafter simply referred to as an embodiment) will be described in detail with reference to the drawings.

  FIG. 1 shows a circuit configuration of a voltage conversion device according to an embodiment of the present invention. This voltage converter functions as a DC-DC converter that converts the high-voltage DC input voltage Vin supplied from the high-voltage battery 10 into a lower DC output voltage Vout and supplies it to a low-voltage battery (not shown) to drive the load 6. Is. The transformer element according to the present embodiment will also be described below.

  This voltage converter includes a switching circuit 1 and an input smoothing capacitor 2 provided between a primary high-voltage line L1H and a primary low-voltage line L1L, a primary winding 31 and a secondary winding 32A, And a transformer 3 having 32B. A DC input voltage Vin output from the high voltage battery 10 is applied between the input terminal T1 of the primary high voltage line L1H and the input terminal T2 of the primary low voltage line L1L. The voltage conversion device also includes a rectifier circuit 4 provided on the secondary side of the transformer 3 and a smoothing circuit 5 connected to the rectifier circuit 4.

  The switching circuit 1 has a full-bridge circuit configuration including four switching elements S1 to S4. Specifically, one ends of the switching elements S1 and S2 are connected to each other, and one ends of the switching elements S3 and S4 are connected to each other. Further, the other ends of the switching elements S1 and S3 are connected to each other and the other ends of the switching elements S2 and S4 are connected to each other, and these other ends are connected to the input terminals T1 and T2, respectively. With such a configuration, the switching circuit 1 converts the DC input voltage Vin applied between the input terminals T1 and T2 into an input AC voltage in accordance with a drive signal supplied from a drive circuit (not shown). . In addition, as these switching elements, switch elements, such as a field effect transistor (MOS-FET; Metal Oxide Semiconductor-Field Effect Transistor) and IGBT (Insulated Gate Bipolor Transistor), are used, for example.

  The input smoothing capacitor 2 is for smoothing the DC input voltage Vin input from the input terminals T1 and T2.

  A pair of secondary windings 32A and 32B of the transformer 3 are connected to each other by a center tap C, and the center tap C is led to an output terminal T3 via an output line LO. That is, this voltage converter is a center tap type. The transformer 3 transforms the input AC voltage generated by the switching circuit 1, and outputs output AC voltages that are 180 degrees out of phase with each other from the ends A and B of the pair of secondary windings 32A and 32B. It is like that. Note that the degree of transformation in this case is determined by the turn ratio between the primary winding 31 and the secondary windings 32A and 32B. The transformer 3 corresponds to a specific example of “transforming element” in the present invention.

  The rectifier circuit 4 is a single-phase full-wave rectifier type composed of a pair of rectifier diodes 4A and 4B. The cathode of the rectifier diode 4A is connected to the other end A of the secondary winding 32A of the transformer 31, and the cathode of the rectifier diode 4B is connected to the other end B of the secondary winding 32B of the transformer 31. The anodes of these rectifier diodes 4A and 4B are connected to each other and connected to the ground line LG. That is, the rectifier circuit 4 has a center tap type anode common connection configuration, and each half wave period of the output AC voltage from the transformer 3 is individually rectified by the rectifier diodes 4A and 4B to generate a DC voltage. To get.

  The smoothing circuit 5 includes a choke coil 51 and an output smoothing capacitor 52. The choke coil 51 is inserted and arranged in the output line LO, one end of which is connected to the center tap C, and the other end is connected to the output terminal T3 of the output line LO. The smoothing capacitor 52 is connected between the output line LO (specifically, the other end of the choke coil 51) and the ground line LG. An output terminal T4 is provided at the end of the ground line LG. With such a configuration, the smoothing circuit 5 generates the DC output voltage Vout by smoothing the DC voltage rectified by the rectifying circuit 4, and supplies this to the low voltage battery (not shown) from the output terminals T3 and T4. It has become.

  Next, with reference to FIG. 2 to FIG. 5, details of the configuration of the transformer 3 and the rectifier circuit 4 which are main characteristic portions of the present embodiment will be described.

  FIG. 2 shows the external appearance of the main part of the voltage converter shown in FIG. 1 (the external configuration of the transformer 3 and the rectifier circuit 4). FIGS. 3 and 4 are exploded views of the external configuration. It is a representation. FIGS. 3 and 4 respectively show the directions from the directions indicated by arrows X3 and X4 in FIG.

  As shown in FIGS. 2 to 4, in this voltage conversion device, a pair of magnetic cores 30 </ b> A and 30 </ b> B constituting the transformer 3, the primary winding 31, the connecting metal plates 33 </ b> A and 33 </ b> B, and the center are formed on the wiring board 70. Electrical components such as the tap sheet metal 33C, the pair of rectifier diodes 4A and 4B constituting the rectifier circuit 4, and the choke coil 51 constituting the smoothing circuit 5 are arranged, and on the back surface and inner layer (not shown) of the substrate, FIG. Are connected to each other in the manner shown in FIG. In addition, although these sheet metal is also called a bus bar, hereafter, it demonstrates as a sheet metal.

  The rectifier diodes 4A and 4B are each provided with four terminals. As shown in FIG. 5, each of the rectifier diodes 4A and 4B includes two rectifier diodes 4A1 and 4A2 or two rectifier diodes 4B1 and 4B2, which are arranged independently of each other. Has been. In this way, two rectifier diodes independent of each other are provided in one electric component, and these are used in parallel connection. Therefore, even when a large current flows, compared to the case where only one rectifier diode is connected. It has become acceptable.

  The choke coil 51 includes a magnetic core 510 and wirings 51 </ b> A and 51 </ b> B wound around the magnetic core 510. The magnetic core 510 is made of a magnetic material such as copper or aluminum, and the wirings 51A and 51B are made of a conductive material such as copper or aluminum.

  The magnetic cores 30A and 30B constituting the transformer 3 have the same shape with the protrusions 30C and 30D provided at the centers, respectively, and are disposed so that the protrusions 30C and 30D face each other. As these magnetic cores 30A and 30B, for example, a magnetic material such as copper or aluminum is used. Further, between the magnetic cores 30A and 30B, a center tap sheet metal 33C, a primary winding 31 and a connecting sheet metal 33A and 33B are laminated in order from the magnetic core 30A side. Through holes H for the protrusions 30C and 30D are provided.

  The primary winding 31 is wound around the magnetic cores 30C and 30D, and is composed of, for example, a printed coil. Further, the connecting metal plates 33A and 33B and the center tap metal plate 33C are also wound around the magnetic cores 30C and 30D to constitute the secondary winding 32. However, the connecting sheet metal 33A and the connecting sheet metal 33B are wound in opposite polar directions with respect to the magnetic cores 30C and 30D. As these metal plates, for example, conductive materials such as copper and aluminum are used. Note that the polar directions in which the connecting sheet metals 33A and 33B are wound may be opposite to each other.

  Each of the connecting metal plates 33A and 33B and the center tap metal plate 33C constitutes a lead-out end, and is connected to the rectifier diodes 4A and 4B and the choke coil 51. Specifically, one end of the connecting sheet metal 33A constitutes a leading end A, and one end of the connecting sheet metal 33A and one end (cathode side) of the rectifier diode 4A are connected to the leading end A. In addition, one end of the connection sheet metal 33B constitutes a lead-out end B, and one end of the connection sheet metal 33B and one end (cathode side) of the rectifier diode 4B are connected to the lead-out end B. Further, one end of the center tap sheet metal 33C constitutes a leading end C, and one end of the center tap sheet metal 33C and one end of the choke coil 51 (wiring 51A) are connected to the leading end C. These lead-out ends A to C correspond to the end portions A and B and the center tap C of the secondary windings 32A and 32B in the transformer 3 shown in FIG.

  Further, these are connected by screws, and are formed by a combination of screws 71 and screw holes 72. Specifically, the connection is made by a pair of screw holes 72A1 and 72A2 provided at one end (cathode side) of the rectifier diode 4A and a pair of screws 71A1 and 71A2 on the coupling metal plate 33A side. In addition, a pair of screw holes 72B1 and 72B2 provided at one end (cathode side) of the rectifier diode 4B and a pair of screws 71B1 and 71B2 on the connecting sheet metal 33B side are connected to each other. Further, the center tap metal plate 33C and the wiring 51A of the choke coil 51 are connected by a screw hole (not shown) and the screw 71E.

  In this voltage converter, the distance between the screw 71A2 on the connection sheet metal 33A side and the screw 71B1 on the connection sheet metal 33B side (the distance between the screw connection parts adjacent to each other in the pair of screw connection parts) is the rectifier diode 4A. , 4B, the interval between the screw hole 72A1 and the screw hole 72A2, or the interval between the screw hole 72B1 and the screw hole 72B2 (interval between the first connection portion and the second connection portion) is configured to be equal to each other. ing. With this configuration, the configuration of the rectifier circuit 4 can be changed as needed according to the magnitude of the circuit current, as will be described later.

  Here, as shown in FIGS. 3 and 4, in this transformer 3, the other ends of the connecting metal plates 33 </ b> A and 33 </ b> B each form 180 ° with the lead ends A to C around the magnetic cores 30 </ b> A and 30 </ b> B. In the direction of the positional relationship, it is connected to the other two ends of the center tap sheet metal 33C. Specifically, the other end of the connection sheet metal 33A and the other end of the center tap sheet metal 33C are connected by a screw 71C and a screw hole 72C, respectively, while the other end of the connection sheet metal 33B and the other end of the center tap sheet metal 33C. The other end is connected by a screw 71D and a screw hole 72D, respectively. Therefore, it is not necessary to divide the drawing end C of the center tap sheet metal 33C in the extending surface direction as in the conventional examples shown in the drawing ends A and B of the connecting sheet metals 33A and 33B and FIGS. It consists of one drawer end.

  Further, as shown by the arrow P1 in FIGS. 3 and 4, these connecting metal plates 33A and 33B are connected to the center tap metal plate 33C so as to cross each other in the direction orthogonal to the respective extending surfaces. Yes. Thus, since it comprised so that it might mutually cross | intersect, the 1st and 2nd connection electroconductive part can be isolated, suppressing the installation space of the trans | transformer 3 to the minimum.

  Each of the connecting metal plates 33A and 33B corresponds to a specific example of the “first connecting conductive portion” and the “second connecting conductive portion” in the present invention, and the center tap metal plate 33 is the “center tap in the present invention”. This corresponds to a specific example of “conductive portion”. Further, the connection sheet metal 33A, 33B and the center tap sheet metal 33C correspond to a specific example of the secondary side winding in the present invention. Each of the drawing ends A to C corresponds to a specific example of “first drawing end”, “second drawing end”, and “center tap drawing end” in the present invention.

  Next, with reference to FIG. 6 and FIG. 7, an operation of the voltage conversion device having the above configuration will be described. First, the basic operation will be described.

  In the switching circuit 1, the input AC voltage is generated by switching the DC input voltage Vin supplied from the input terminals T 1 and T 2, and this input AC voltage is supplied to the primary winding 31 of the transformer 3. In the transformer 3, the input AC voltage is transformed, and the transformed output AC voltage is output from the secondary windings 32A and 32B.

  In the rectifier circuit 4, this output AC voltage is rectified by the rectifier diodes 4A and 4B. As a result, a rectified output is generated between the center tap C (output line LO) and the connection point D1 between the rectifier diodes 4A and 4B.

  In the smoothing circuit 5, the rectified output generated between the center tap C (output line LO) and the connection point D1 of the rectifying diodes 4A and 4B is smoothed and output as the DC output voltage Vout from the output terminals T3 and T4. . The DC output voltage Vout is fed to a low-voltage battery (not shown) to be charged, and the load 6 is driven.

  Here, in this voltage converter, in the switching circuit 1, the period in which the switching element elements S1, S4 are turned on and the period in which the switching elements S2, S3 are in the on state are alternately repeated. Yes. Therefore, the operation of the voltage converter will be described in detail as follows.

  First, as shown in FIG. 6, when the switching elements S1 and S4 of the switching circuit 1 are turned on, the primary loop current Ia1 flows from the switching element S1 to the switching element S4. Then, the voltages VOA and VOB appearing on the secondary windings 32A and 32B of the transformer 3 are in the reverse direction with respect to the rectifier diode 4B, and are in the forward direction with respect to the rectifier diode 4A. For this reason, the output current Ix flows from the rectifier diode 4A to the secondary winding 32A and the output line LO. As a result, the DC output voltage Vout is supplied to a low voltage battery (not shown) and the load 6 is driven.

  At this time, the secondary loop current Ia2 that passes through the rectifier diode 4A, the secondary winding 32A of the transformer 3, the choke coil 51, and the capacitor 52 also flows, and charging (accumulation of energy) to the capacitor 51 occurs. To be done.

  On the other hand, as shown in FIG. 7, when the switching elements S1 and S4 of the switching circuit 1 are turned off and the switching elements S2 and S3 are turned on, the primary loop in the direction from the switching element S3 to the switching element S2 is performed. Current Ib1 flows. Then, the voltages VOA and VOB appearing in the secondary windings 32A and 32B of the transformer 3 are in the reverse direction with respect to the rectifier diode 4A, and are in the forward direction with respect to the rectifier diode 4B. For this reason, the output current Ix flows from the rectifier diode 4B to the secondary winding 32B and the output line LO. As a result, the DC output voltage Vout is supplied to a low voltage battery (not shown) and the load 6 is driven.

  At this time, the secondary loop current Ib2 that passes through the rectifier diode 4B, the secondary winding 32B of the transformer 3, the choke coil 51, and the capacitor 52 also flows, and charging (accumulation of energy) to the capacitor 51 is performed. To be done.

  Here, in the transformer 3 of the present embodiment, as described above, the other end of each of the connecting metal plates 33A and 33B is in a positional relationship in which the other ends form 180 ° with respect to the lead ends A to C around the magnetic core 30B. Are connected to the other two ends of the center tap sheet metal 33C, whereby the drawing end C of the center tap sheet metal 33C is constituted by one drawing end. Therefore, the wiring width of the lead-out end C constituting the center tap becomes wider than that of the conventional case, and the cross-sectional area thereof also increases as compared with the conventional case.

  8 and 9 schematically show the state of current flowing through the end portions (leading ends A to C) of each sheet metal in the transformer 3 in the cross-sectional configuration taken along the lines II and II-II in FIG. 8 (A) and FIG. 9 (A) correspond to the II portion, and FIGS. 8 (B) and 9 (B) correspond to the II-II portion. . 8 shows a current state when the rectifier diode 4A is conductive, that is, when the secondary loop current Ia2 shown in FIG. 6 flows, and FIG. 9 shows a case where the rectifier diode 4B is conductive. That is, the current state when the secondary loop current Ib2 shown in FIG. 7 flows is shown. In any current state, the lead-out end portion through which the current flows is indicated by hatching.

  As shown in FIGS. 8A and 8B, when the secondary loop current Ia2 is flowing, as can be seen from FIG. 6, in the transformer 3, the connecting sheet metal 33A constituting the lead-out end A is formed. The current Ia2 flows through the center tap metal plate 33C constituting the lead-out end C. Here, in the cross section (FIG. 8B) on the side where the connecting sheet metal 33A, 33B and the center tap sheet metal 33C are connected, the current Ia2 is the same as in the conventional transformer shown in FIGS. The cross-sectional area of the flowing drawer end is ½ of the entire drawer end. On the other hand, in the cross-section (FIG. 8A) on the side of the drawing ends A to C, that is, the connection side with the rectifying circuit 4 and the smoothing circuit 5, the drawing end C of the center tap sheet metal 33C is one as described above. Since it is composed of a lead end and its wiring width is wider than the conventional one, the cross-sectional area of the lead end through which the current Ia2 flows is 3/4 of the whole lead end. Therefore, as compared with the conventional one shown in FIGS. 18 and 19, the ratio of the leading end where the current occupies the entire leading end is increased by ¼.

  Also, when the secondary loop current Ib2 shown in FIGS. 9A and 9B flows, as can be seen from FIG. 7, in the transformer 3, the connecting sheet metal 33B constituting the lead-out end B and A current Ib2 flows through the center tap sheet metal 33C constituting the lead-out end C. Similarly to the case of FIG. 8B, in the cross section (FIG. 9B) on the side where the connection sheet metal 33A, 33B and the center tap sheet metal 33C are connected (FIG. 9B), the cross-sectional area of the extraction end through which the current Ib2 flows. Becomes 1/2 of the whole drawing end. Also, in the cross section on the drawing end A to C side (FIG. 9A), similarly to the case of FIG. 8A, the sectional area of the drawing end through which the current Ib2 flows is 3 / of the entire drawing end. 4. Therefore, also in this case, the ratio of the leading end through which the current occupies the entire leading end is increased by ¼ compared to the conventional one.

  As described above, in the transformer 3 of the present embodiment, since the wiring width of the lead end C constituting the center tap is wider than that of the conventional case, the cross-sectional area thereof is increased as compared with the conventional case, and the current occupying the entire lead end is increased. It can be seen that the proportion of the withdrawal end flowing is increasing.

  As described above, in the present embodiment, the other ends of the connecting metal plates 33A and 33B in the transformer 3 are positioned in the direction of the positional relationship that forms 180 ° with the lead ends A to C around the magnetic cores 30A and 30B. Since it is connected to the other two ends of the center tap sheet metal 33C, the drawing end C of the center tap sheet metal 33C can be constituted by one drawing end, and the wiring width of the drawing end C can be made wider than before. Can do. Accordingly, the cross-sectional area of the lead end C constituting the center tap is increased, and the wiring resistance of the lead-out portion on the secondary side of the transformer 3 can be reduced.

  In addition, since the wiring resistance at the lead-out end C is reduced, the voltage drop at this portion can also be reduced. Therefore, even when a large current is passed through the transformer 3, a voltage drop can be suppressed as compared with the conventional case, and the transformer 3 and the voltage conversion circuit that can handle the large current can be realized.

  Furthermore, since the interval between the screw 71A2 on the connection sheet metal 33A side and the screw 71B1 on the connection sheet metal 33B side is configured to be equal to the adjacent interval between the screw holes 72A1, 72A2, 72B1, 72B2 in the rectifier diodes 4A, 4B, The configuration of the rectifier circuit 4 is changed as needed, for example, as shown in FIG. 10, according to the magnitude of the circuit current (primary side loop currents Ia1, Ib1 and secondary side loop currents Ia2, Ib2) in the voltage converter. can do. Specifically, when the circuit current is large, the rectifier circuit 4 is configured by using the two rectifier diodes 4A and 4B as shown in FIGS. As shown in FIG. 10, the rectifier circuit 4 shown in FIG. 11 can be configured by using one rectifier diode. Therefore, it is possible to change the number of rectifier diodes by using multiple parts with the same configuration, instead of replacing them with parts having different configurations. It is also possible to reduce the component cost.

  In the transformer 3 of the present embodiment, as described above, the other ends of the connection metal plates 33A and 33B are positioned in the direction of the positional relationship that forms 180 ° with the lead ends A to C around the magnetic cores 30A and 30B. Although the description has been given of the case where the center tap sheet metal 33C is connected to the other two ends, the position where these are connected is not limited to this case, and more generally, the magnetic direction is different from the extending direction of the drawing ends A to C. What is necessary is just to make it connect with the other side of core 30A, 30B. Further, in the transformer 3 of the present embodiment, these have been described in the case where they are connected so as to intersect each other on the respective extending surfaces as indicated by the arrow P1 in FIGS. As long as the metal plates 33A and 33B can be connected while being isolated, the configuration is not limited to this.

  While the present invention has been described with reference to the embodiment, the present invention is not limited to this embodiment, and various modifications can be made.

  For example, in the above embodiment, the sheet metal constituting the secondary side winding 32 is composed of three separate members (connection sheet metal 33A, 33B and center tap sheet metal 33C), which are screw 71 and screw hole 72. However, for example, as shown in FIG. 12, the secondary winding 32 may be formed of a single member (single sheet metal 34). Specifically, the single sheet metal 34 includes first and second connecting portions 34A and 34B each having a lead portion A and B, and a center tap portion 34 having a lead portion C, and includes a magnetic core 30A. , 30B through-holes H for the protrusions 30C, 30D are also provided. The single sheet metal 34 having such a shape is valley-folded at the fold lines F1 to F5 shown in FIG. 12, and is fold-folded at the fold line F10, whereby each of FIGS. 13A and 13B is viewed from above or below. A sheet metal as shown in the perspective view is formed. Therefore, when the transformer 3 is configured using this single sheet metal 34 instead of the connection sheet metal 33A, 33B and the center tap sheet metal 33C, the number of parts of the sheet metal is reduced, and in addition to the effects in the above embodiment, the management cost is reduced. It becomes possible to reduce. The single sheet metal 34 corresponds to a specific example of “single conductive member” in the present invention.

  In the above-described embodiment, the configurations of the voltage conversion device and the transformer 3 are specifically described. However, these configurations are not limited to this, and other configurations may be used. For example, instead of the full-bridge type switching circuit 1, as shown in FIG. 14, a half-bridge type switching circuit 11 (FIG. 14A) including two switching elements S1 to S2 and two capacitors C1 and C2. ) Or a push-pull type switching circuit 12 (FIG. 14B) including two switching elements S1 and S2. For example, instead of the rectifier circuit 4 of the center tap type anode common connection, as shown in FIG. 15, the center tap type cathode common connection in which the cathodes of the two rectifying elements 4A and 4B are connected at the connection point D2. The rectifier circuit 41 may be used.

  Further, in the above embodiment, the case where the transformer 3 has the magnetic cores 30, 30A, 30B has been described. However, the magnetic cores 30, 30A, 30B may be omitted, and a coil having an air core configuration may be used. Even when configured in this manner, the same effects as those of the above-described embodiment can be obtained. The air core portion, that is, the region where the magnetic cores 30, 30 </ b> A, 30 </ b> B are arranged corresponds to a specific example of “predetermined space region” in the present invention.

It is a circuit diagram showing the structure of the voltage converter which concerns on one embodiment of this invention. It is a perspective view showing the external appearance structure of the transformer and rectifier circuit of FIG. It is a disassembled perspective view showing the external appearance structure of the transformer and rectifier circuit of FIG. FIG. 6 is another exploded perspective view showing the external configuration of the transformer and rectifier circuit of FIG. 1. It is a circuit diagram for demonstrating the connection relation of the trans | transformer and rectifier of FIG. It is a circuit diagram for demonstrating operation | movement of the voltage converter of FIG. FIG. 6 is another circuit diagram for explaining the operation of the voltage conversion device of FIG. 1. It is a schematic cross section for demonstrating the state of the electric current which flows into the secondary side of the transformer of FIG. FIG. 6 is another schematic cross-sectional view for explaining a state of current flowing through the secondary side of the transformer of FIG. 1. It is a perspective view showing the external appearance structure of the transformer and rectifier circuit which concern on the modification of this invention. It is a circuit diagram for demonstrating the connection relation of the trans | transformer and rectifier of FIG. It is a top view showing the structure of the sheet metal of the secondary side of the transformer which concerns on the other modification of this invention. It is a perspective view showing the structure of the sheet metal of FIG. It is a circuit diagram showing the structure of the switching circuit which concerns on the other modification of this invention. It is a circuit diagram showing the structure of the rectifier circuit which concerns on the other modification of this invention. It is a schematic diagram showing the external appearance structure of the trans | transformer in the conventional voltage converter. It is a schematic diagram showing the external appearance structure of the other transformer in the conventional voltage converter. It is a schematic cross section for demonstrating the state of the electric current which flows into the secondary side of the transformer of FIG. It is a schematic cross section for demonstrating the state of the electric current which flows into the secondary side of the transformer of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... High voltage battery, 1, 11, 12 ... Switching circuit, 2 ... Input smoothing capacitor, 3 ... Transformer 30, 30A, 30B ... Magnetic core, 30C, 30D ... Projection part, 31, 31A, 31B ... Primary side winding Wire, 32A, 32B ... Secondary winding, 33A, 33B ... Connection sheet metal, 33C ... Center tap sheet metal, 34 ... Single sheet metal, 34A ... First connection part, 34B ... Second connection part, 34C ... Center tap part 4, 41 ... Rectifier circuit, 4A, 4B, 4C ... Rectifier diode, 5 ... Smoothing circuit, 51 ... Choke coil, 52 ... Output smoothing capacitor, 6 ... Load, 70 ... Wiring board, 71, 71A1, 71A2, 71B1, 71B2, 71C, 71D, 71E ... screws, 72, 72A1, 72A2, 72B1, 72B2 ... screw holes, S1 to S4, S5, S6 ... switching elements, C1, C2 ... co Densers, L1H ... Primary high voltage line, L1L ... Primary low voltage line, LO ... Output line, LG ... Ground line, T1, T2 ... Input terminal, T3, T4 ... Output terminal, A, B ... End (drawer) End), C ... center tap (drawing end), H ... through hole, F1 to F5, F10 ... fold, Vin ... DC input voltage, Vout ... DC output voltage, Ia1, Ib1, primary loop current, Ia2, Ib2 ... secondary loop current, Ix ... output current.

Claims (9)

A magnetic core,
A primary winding wound around the magnetic core;
And a secondary winding in which the first and second lead ends and the center tap lead end are provided on one side of the magnetic core, and wound around the magnetic core.
The secondary winding is
A first connecting conductive portion that is wound in one polarity direction with respect to the magnetic core, and has one end constituting the first lead-out end;
A second connecting conductive portion wound around the magnetic core in another polarity direction, one end of which constitutes the second lead end;
One end constitutes the center tap lead-out end, and the other two ends each have a center tap conductive portion connected to each other end of the first and second connection conductive portions on the other side of the magnetic core. A transformer element characterized by that. The transformer element according to claim 1, wherein one side and the other side of the magnetic core are in a positional relationship of 180 ° with the magnetic core as a center. The said 1st and 2nd connection electroconductive part is comprised so that it may mutually cross | intersect in the direction orthogonal to each extension surface. The transformer element of Claim 1 or Claim 2 characterized by the above-mentioned. The first and second connecting conductive portions and the center tap conductive portion are formed of separate members and connected to each other by screws. Transformer element given in the paragraph. 4. The transformer element according to claim 1, wherein the first and second connection conductive portions and the center tap conductive portion are formed of a single member. 5. 6. The transformer element according to claim 4, wherein the first and second connecting conductive portions and the center tap conductive portion are configured by plate-like members. A switching circuit that switches a DC input voltage to generate an input AC voltage;
A transformer element that transforms the input AC voltage and outputs an output AC voltage;
A center tap type rectifier circuit which has two rectifier elements and outputs a DC output voltage by rectifying the output AC voltage by these rectifier elements;
A drive circuit for driving the switching circuit,
The transformer element is
A magnetic core,
A primary winding wound around the magnetic core and supplied with the input AC voltage;
A first lead-out end wound around the magnetic core and connected to one of the two rectifying elements; a second lead-out end connected to the other rectifying element; and A center tap lead-out end for connecting to the center tap of the rectifier circuit is provided on one side of the magnetic core, and between the first connection end and the center tap connection end or between the second connection end and the center. A secondary winding from which the output AC voltage is output between the tap connection ends,
The secondary winding is
A first connecting conductive portion that is wound in one polarity direction with respect to the magnetic core, and has one end constituting the first lead-out end;
A second connecting conductive portion wound around the magnetic core in another polarity direction, one end of which constitutes the second lead end;
One end constitutes the center tap lead-out end, and the other two ends each have a center tap conductive portion connected to each other end of the first and second connection conductive portions on the other side of the magnetic core. A voltage converter characterized by that. The two rectifying elements are composed of first and second rectifying elements, and first and second screw connection portions for connecting one ends of the first and second rectifying elements with screws. Each provided independently in a single part,
The first and second lead ends each have a pair of screw connection parts for connecting the first connection conductive part or the second connection conductive part with screws,
The first lead end or the second lead end and the first rectifier element or the second rectifier element are respectively the first and second screw connection portions and the pair of screw connection portions. And are configured to be connected to each other with screws,
The interval between the first screw connection portion and the second screw connection portion in the single component, and the interval between the screw connection portions adjacent to each other at the first extraction end and the second extraction end. Are configured to be equal to each other. The voltage converter according to claim 7. A primary winding wound in a predetermined space region;
A secondary winding wound around the space region, the first and second lead ends and the center tap lead end provided on one side of the space region, and
The secondary winding is
A first connecting conductive portion wound in one polarity direction with respect to the space region, and having one end constituting the first lead-out end;
A second connecting conductive portion which is wound in the other polarity direction with respect to the space region, and has one end constituting the second lead-out end;
One end constitutes the center tap lead-out end, and the other two ends each have a center tap conductive portion connected to each other end of the first and second connection conductive portions on the other side of the space region. A coil characterized by that.

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