JPWO2011154993A1 - Isolation transformer and power supply - Google Patents

Abstract

The problem to be solved by the present invention is to reduce the primary-secondary parasitic capacitance and reduce the volume of the insulation transformer in a high voltage insulation transformer. Therefore, the insulation transformer has a primary side iron core around which the primary winding is wound, a secondary side iron core around which the secondary winding is wound, and an insulator, and the primary side iron core. And the secondary iron core are fixed and arranged on the insulator so as to face each other with the insulator interposed therebetween. In addition, the power supply device includes a primary side iron core around which the primary winding is wound, a secondary side iron core around which the secondary winding is wound, and an insulator. An insulating transformer fixed and arranged on the insulator so that the side iron cores are opposed to each other with the insulator interposed therebetween, a primary circuit connected to the primary winding of the insulating transformer, and a secondary winding of the insulating transformer The isolation transformer is mounted on the printed circuit board together with circuit components constituting the primary side circuit and the secondary side circuit.

Description

  The present invention relates to an insulation transformer that obtains insulated power and a power supply device configured using the insulation transformer.

  In a power supply for a gate drive of a railway vehicle inverter, a power supply for a large industrial device, etc., a relatively high voltage of 6 to 25 kV is required as a withstand voltage between primary and secondary. In addition, when a lightning surge occurs, it is required to make the parasitic capacitance between the primary and secondary as small as possible from the viewpoint of preventing malfunction of the device due to noise current.

  For this reason, an insulating transformer having a high withstand voltage and a low parasitic capacitance is used to realize the insulating function. In addition, the insulation transformer needs to increase the distance between the primary winding and the secondary winding, and there is a problem that the volume of the insulation transformer increases.

  Among these problems to be solved, a low parasitic capacitance transformer as shown in Patent Document 1 has been proposed for reducing parasitic capacitance. This transformer is a multi-layered transformer, and the insulation between the fourth coil layer of the primary coil and the third coil layer of the secondary coil is made thicker than the thickness of the insulation between the other coil layers. The space between the third and fourth coil layers is widened, and the parasitic capacitance between the primary coil and the secondary coil is reduced.

JP-A-10-106855

  In the above-mentioned Patent Document 1, a method of increasing the thickness of an insulator to ensure a withstand voltage and reducing parasitic capacitance is used. Multiple insulators are required, and it is difficult to reduce the transformer volume.

  The problem to be solved by the present invention is to reduce the primary-secondary parasitic capacitance and reduce the volume of the insulation transformer in a high voltage insulation transformer.

  The insulation transformer of the present invention has a primary side iron core around which a primary winding is wound, a secondary side iron core around which a secondary winding is wound, and an insulator. And the secondary iron core are fixed and arranged on the insulator so as to face each other with the insulator interposed therebetween.

  The primary side iron core and the secondary side iron core are pot-type ferrite cores, and the primary winding and the secondary winding are respectively disposed in the openings of the core so that the openings are opposed to each other. It is preferable to face each other with an insulator interposed therebetween.

  The primary side iron core and the secondary side iron core are E-type ferrite cores, and are preferably opposed to each other with an insulator interposed therebetween so that the legs of the cores face each other.

  The insulator is composed of two insulators having a gap in the middle. The primary iron core on one insulator side and the secondary iron core on the other insulator side face each other across the insulator. It is good to be arranged.

  The insulator is preferably a printed board on which electronic components are mounted.

  The insulating transformer of the present invention has a primary side iron core around which a primary winding is wound and a secondary side iron core around which a secondary winding is wound, arranged via a gap, and is insulated at least in the gap. The primary side iron core and the secondary side iron core winding are disposed so as to face each other.

  An insulating transformer according to the present invention includes a primary iron core around which a primary winding is wound and a secondary iron core around which a secondary winding is wound, arranged via an insulator, at least of the iron core. The periphery is covered with an insulating resin, and the winding surfaces of the primary side iron core and the secondary side iron core winding are arranged to face each other.

  The power supply device of the present invention has a primary side iron core around which a primary winding is wound, a secondary side iron core around which a secondary winding is wound, and an insulator. And a secondary side iron core is provided with an insulating transformer fixed and arranged on the insulator so as to face each other across the insulator, and the circuit method for exciting the insulating transformer is a series resonance method using the leakage inductance of the insulating transformer. Is done.

  The power supply device of the present invention has a primary side iron core around which a primary winding is wound, a secondary side iron core around which a secondary winding is wound, and an insulator. An insulation transformer fixed and arranged on the insulator so that the secondary iron core is opposed to the insulator, a primary circuit connected to the primary winding of the insulation transformer, and a secondary winding of the insulation transformer And an isolation transformer is mounted on a printed circuit board together with circuit components constituting the primary side circuit and the secondary side circuit.

  The insulator of the insulating transformer is the printed board, and the primary side iron core and the secondary side iron core are preferably arranged on each surface of the printed board.

  The insulator of the insulation transformer is arranged such that the insulator is fixed vertically on the printed circuit board, the primary iron core is adjacent to the primary circuit, and the secondary iron core is 2 It is good to arrange | position so that a secondary side circuit may be adjoined.

  Further, the circuit components constituting the secondary circuit are preferably surface-mounted on the printed board.

  The power supply apparatus of the present invention incorporating at least one power switching device and its drive circuit incorporates an insulation transformer for supplying power to the drive circuit, and the insulation transformer is a primary side around which a primary winding is wound. It has an iron core and a secondary iron core around which a secondary winding is wound, and the primary iron core and the secondary iron core face each other with a filler filled on the drive circuit board interposed therebetween. And at least the primary iron core is fixed by a filler.

  The number of insulation transformers to be mounted is preferably the same as the number of power switching elements.

  Also, it is preferable to connect as many isolation transformers as the number of power switching elements in series.

  According to the present invention, it is possible to provide an isolation transformer that can reduce the primary-secondary parasitic capacitance and can suppress the generation of noise current when a lightning surge occurs.

The exploded block diagram which shows 1st Embodiment of an insulation transformer. The exploded block diagram which shows 2nd Embodiment of an insulation transformer. The circuit block diagram which shows an example of the power supply device using an insulation transformer. The circuit block diagram which shows an example of the power supply device using an insulation transformer. The layout which shows an example of the board | substrate mounting of the power supply device using an insulation transformer. The layout which shows an example of the board | substrate mounting of the power supply device using an insulation transformer. The layout which shows an example of the board | substrate mounting of the power supply device using an insulation transformer. Sectional drawing which shows an example of the insulation transformer by which the mold was formed. Sectional drawing which shows an example of the insulation transformer by which the mold was formed. The block diagram of the power module using an insulation transformer. Sectional drawing of the power module using an insulation transformer. Sectional drawing of the power supply device for power modules using an insulation transformer.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In particular, the configuration of the insulation transformer, the configuration of the power supply device including the insulation transformer, the mounting of the power supply device on the printed board, the molding of the insulation transformer, and the power supply device configured as a power module will be described sequentially by several examples.

  First, an example of the configuration of the insulation transformer of the present invention will be described with reference to FIGS.

  FIG. 1 is an exploded configuration diagram of an insulating transformer 19 according to the present invention. In this structure, the transformer primary part 11 is arranged on one side of the insulating plate 3 and the transformer secondary part 12 is arranged on the other side. The transformer primary part 11 and the transformer secondary part 12 house the primary and secondary windings 2 and 4 in the pot type ferrite core 1. The insulating plate 3 is not provided with a hole or the like, and is disposed so that the transformer primary portion 11 and the transformer secondary portion 12 face each other through the insulating plate.

  Hereinafter, in more detail, in FIG. 1, cores 1a and 1b are circular so-called pot-type ferrite cores, which have cylindrical legs (1a1 and 1b1) at the center of the circle, and also at the periphery. It has a cylindrical leg (1a2 and 1b2), and has a shape having a space (1a3 and 1b3) recessed in a donut shape when viewed from the opening.

  The primary winding 2 is wound in a spiral shape around a hollow portion 1 a 3 centered on the center leg of the core 1 a to form a transformer primary portion 11. Similarly to the core 1a, the secondary windings 4a and 4b are also spirally wound around the hollow portion 1b3 of the core 1b to form the transformer secondary portion 12. An enameled wire (single wire) is used for the primary winding 2 and the secondary windings 4a and 4b, but a litz wire may be used.

  The insulating plate 3 is an insulator and uses a material having a relatively low dielectric constant. The dielectric constant of the insulator is: paper: 2.0 to 2.5, polyethylene: 2.3 to 2.4, polyester: 2.8 to 8.1, phenol resin: 3.0 to 12.0, porcelain: 4.0 to 7.0, glass / epoxy substrate: 4.5 to 5.2, polyurethane: 5.0 to 5.3, mica: 5.7 to 7.0, etc. The parasitic capacitance can be reduced by particularly selecting a material having a low rate characteristic.

  The insulating plate 3 is the same as or larger than the bottom surface of the pot type ferrite cores 1a and 1b. In the case of widening, it is possible to ensure a longer edge distance between the primary and secondary sides.

  On the other hand, the thickness of the insulating plate 3 is approximately 0.3 mm to 5.0 mm. The thicker the thickness, the higher the withstand voltage, and the parasitic capacitance can be reduced. On the other hand, the coupling between the primary and secondary is reduced, leading to a reduction in power supply efficiency. However, in the present invention, priority is given to improving reliability and reducing costs by reducing the withstand voltage and parasitic capacitance over the coupling between the primary and secondary.

  The transformer primary part 11 and the transformer secondary part 12 described above are such that the core recesses (1a3 and 1b3) wound with the windings face the insulating plate 3 so that the front side and the back side of the insulating plate 3 are facing each other. It fixes to the insulating board 3 so that it may oppose. At this time, lead wires connected to the respective windings are drawn from between the transformer primary part 11, the transformer secondary part 12 and the insulating plate 3.

  FIG. 2 is an exploded configuration diagram showing a second embodiment of an insulating transformer 19 according to the present invention. In FIG. 2, the basic principle is the same as in FIG. 1, but in the case of FIG. 1, there is an advantage that the magnetic flux is difficult to leak, but a pot type ferrite core that is relatively difficult to manufacture is used. However, since it is unavoidable to be expensive, an existing core that is generally used and easy to manufacture is used.

  In FIG. 2, each of the cores 1a and 1b is an E-shaped ferrite core, and has a total of three legs, the center leg is thick, and the two legs at both ends are thin. The primary winding 2 is wound around the center leg of the core 1 a to form a transformer primary portion 11. Similarly to the core 1a, secondary windings 4a and 4b are wound around the center leg of the core 1b to form a transformer secondary portion. Although not shown, a bobbin may be used when the primary winding and the secondary winding are wound and fixed to the core. An enameled wire (single wire) is used for the primary winding 2 and the secondary windings 4a and 4b, but a litz wire may be used.

  The insulating plate 3 is an insulator and uses a material having a relatively low dielectric constant. The parasitic capacitance can be reduced by selecting a material having a low dielectric constant value. By making the insulating plate 3 wider than the size of the bottom surface of the E-type ferrite core, it is possible to sufficiently secure the edge distance between the primary and secondary.

  On the other hand, the thickness of the insulating plate 3 is approximately 0.3 mm to 5.0 mm. The thicker the thickness, the higher the withstand voltage, and the parasitic capacitance can be reduced. On the other hand, the coupling between the primary and secondary is reduced, leading to a reduction in power supply efficiency. However, in the present invention, priority is given to improving the reliability and reducing the cost by reducing the withstand voltage and parasitic capacitance over the coupling between the primary and secondary.

  The transformer primary portion 11 and the transformer secondary portion 12 are opposed to the front side and the back side of the insulating plate 3 so that the tip ends of the core legs wound with the windings face the insulating plate 3. And fix to the insulating plate 3.

  1 and 2, the core has several shapes. In short, it is important to arrange the winding surfaces of the primary and secondary windings to face each other.

  Next, a circuit configuration example of the power supply device including the insulating transformer 19 of FIG. 1 or FIG. 2 will be described with reference to FIGS. FIG. 3 is a circuit configuration of a power supply device that rectifies the output of the isolation transformer 19 and supplies power to the load, and FIG. 4 is a circuit configuration of a power supply device that rectifies the output of the isolation transformer 19 and supplies power to a plurality of loads. is there. Needless to say, when the power supply is configured using the insulating transformer 19 of FIGS. 1 and 2, the primary side circuit 8 and the secondary side circuit 9 can be arbitrarily set. Is shown.

  First, the configuration of FIG. 3 will be described. FIG. 3 is a circuit configuration diagram of a power supply device using the insulating transformer 19 of FIG. 1 or FIG. In this figure, the portion comprising the central insulating plate 3, the transformer primary portion 11, and the transformer secondary portion 12 is the insulating transformer of FIG. 1 or FIG. The transformer primary part 11 side is connected to the DC power source 7 via the primary side circuit 8, and the transformer secondary part 12 side is connected to the load 10 a via the secondary side circuit 9.

  Hereinafter, in more detail, in FIG. 3, the DC power supply 7 is connected to the primary circuit 8. The primary side circuit 8 includes a smoothing capacitor 20a, power MOSFETs 21a and 21b connected in series, a drive circuit 22, a resonance capacitor 23, a lossless snubber capacitor 24, an insulation signal receiving unit 25, and a control circuit 29, and the power MOSFETs 21a and 21b. A resonance capacitor 23 is connected to the midpoint of the series body.

  The source electrodes of the resonance capacitor 23 and the power MOSFET 21 b are connected to the transformer primary unit 11 outside the primary circuit 8. The transformer primary part 11 is magnetically coupled to the transformer secondary part 12 via the insulating plate 3. The transformer secondary unit 12 has a center tap configuration and is connected to rectifier diodes 26 a and 26 b in the secondary side circuit 9.

  Further, in the secondary side circuit 9, there are a smoothing capacitor 20 b connected to the rectifier diodes 26 a and 26 b, an output voltage error amplifier circuit 27, and an insulation signal transmission unit 28, and the primary side circuit 8 is connected via the optical cable 18. A signal is transmitted to the control circuit 29 from the insulated signal receiving unit 25.

  Next, the operation of the circuit of FIG. 3 will be described. The control circuit 29 generates a pulse signal in accordance with the signal input from the insulation signal receiving unit 25 and outputs it to the drive circuit 22. The drive circuit 22 sends a gate signal to the power MOSFETs 21a and 21b to switch the power MOSFETs 21a and 21b. At this time, the output control is frequency control, and the ON / OFF time ratio of the power MOSFETs 21a and 21b is constant without changing according to the output, and the drive frequency changes instead.

  The transformer primary part 11 and the transformer secondary part 12 are magnetically coupled via the insulating plate 3, but since the ferrite iron core is separated by the insulating plate 3, the leakage inductance is higher than that of the conventional insulating transformer. Relatively large. Therefore, in this embodiment, this leakage inductance is used effectively. That is, by driving the power MOSFETs 21a and 21b at a frequency higher than the resonance frequency of this circuit, a resonance current flows through the series resonance circuit formed by the leakage inductance and the resonance capacitor 24, and the transformer secondary unit 12 receives power. Communicated.

  In the secondary side circuit 9, the rectification diodes 26a and 26b rectify the high-frequency alternating current transmitted to the transformer secondary part and store it in the smoothing capacitor 20b. The load 10a obtains a stable output by the smoothing capacitor 20b. The voltage of the smoothing capacitor 20b is amplified from the output voltage command value by the output voltage error amplification circuit 27, and a signal is transmitted to the control circuit 29 via the insulation signal transmission unit 28, the optical cable 18, and the insulation signal reception unit 25. The frequency for driving the power MOSFETs 21a and 21b changes to control the output voltage to be constant.

  In FIG. 2, the insulation signal transmission unit 28, the optical cable 18, and the insulation signal reception unit 25 may use an optical fiber transmission link such as an opt-wire or an isolator such as an EAIJ optical fiber optic connector called a toss link. Further, a shunt regulator may be used for the output voltage error amplifier circuit 27.

  Next, the configuration of FIG. 4 will be described. FIG. 4 is a circuit configuration diagram according to another embodiment of the power supply device using the insulating transformer 19 of FIG. 1 or FIG. In FIG. 4, devices having the same functions as those in FIG. In particular, since the primary side overlaps with the circuit configuration of FIG. 3, its description is omitted.

  The transformer secondary unit 12 has a center tap configuration and is connected to rectifier diodes 26 a and 26 b in the secondary side circuit 9. 4 differs from FIG. 3 in that the secondary side circuit 9 is provided with a smoothing capacitor 20c in addition to the smoothing capacitor 20b. The configuration of the rectifier diode is also different from that shown in FIG. 3, and the smoothing capacitor 20c forms a negative potential power supply having the ground potential of the smoothing capacitor 20b as a positive electrode, and supplies power to the second load 10b. In addition, the secondary side circuit 9 includes an output voltage error amplification circuit 27 and an insulation signal transmission unit 28, and the control circuit 29 via the optical cable 18 and the insulation signal reception unit 25 of the primary side circuit 8. A signal is transmitted to.

  Next, the circuit operation of FIG. 4 will be described. The control circuit 29 generates a pulse signal in accordance with the signal input from the insulation signal receiving unit 25 and outputs it to the drive circuit 22. The drive circuit 22 sends a gate signal to the power MOSFETs 21a and 21b to switch the power MOSFETs 21a and 21b. At this time, the output control is frequency control, and the ON / OFF time ratio of the power MOSFETs 21a and 21b is constant without changing according to the output, and the drive frequency changes instead.

  The transformer primary part 11 and the transformer secondary part 12 are magnetically coupled via the insulating plate 3, but since the ferrite iron core is separated by the insulating plate 3, the leakage inductance is compared with the conventional insulating transformer. Big. Therefore, in the present invention, this leakage inductance is effectively used. That is, by driving the power MOSFETs 21a and 21b at a frequency higher than the resonance frequency of this circuit, a resonance current flows through the series resonance circuit formed by the leakage inductance and the resonance capacitor 24, and the transformer secondary unit 12 receives power. Communicated.

  In the secondary side circuit 9, the rectifier diodes 26a and 26b rectify the high-frequency alternating current transmitted to the secondary part of the transformer and store it in the smoothing capacitors 20b and 20c. The loads 10a and 10b obtain stable voltages by the smoothing capacitors 20b and 20c, respectively.

  The voltage of the smoothing capacitor 20b is amplified from the output voltage command value by the output voltage error amplification circuit 27, and a signal is transmitted to the control circuit 29 via the insulation signal transmission unit 28, the optical cable 18, and the insulation signal reception unit 25. The frequency for driving the power MOSFETs 21a and 21b changes to control the output voltage to be constant.

  In FIG. 4, the insulation signal transmission unit 28, the optical cable 18, and the insulation signal reception unit 25 may use an optical fiber transmission link such as an opt-wire or an isolator such as an EAIJ optical fiber connector called a toslink. Further, a shunt regulator may be used for the output voltage error amplifier circuit 27.

  Next, a technique for mounting circuit components constituting the power supply device of FIG. 3 or FIG. 4 on a printed board will be described with reference to FIG. 5, FIG. 6, and FIG. In these embodiments, a primary circuit 8 and a secondary circuit 9 are also mounted on the printed board 6 in addition to the insulating transformer.

  First, FIG. 5 will be described. FIG. 5 is a cross-sectional view of a substrate on which circuit components constituting the power supply device of FIG. 3 or FIG. 4 are mounted as seen from the lateral direction. In addition to the insulating transformer 19 having the structure shown in FIG. 1, a primary side circuit 8 and a secondary side circuit 9 are mounted on the printed board 6 shown in FIG. 1 to form a power supply device as a unit.

  Hereinafter, in more detail, the primary circuit 8 is mounted on the left side of the printed circuit board 6 in FIG. The insulating transformer 19 shown in FIG. 1 or FIG. 2 is mounted and arranged at the center. The insulating transformer 19 is centered on the insulating plate 3 provided upright on the printed circuit board 6, and the left side where the primary side circuit 8 is mounted is the right side where the transformer primary part 11 and the secondary side circuit 9 are mounted. It is mounted so as to be the transformer secondary unit 12.

  The mounting components for the primary side circuit 8 include a smoothing capacitor 20a, a power MOSFET 21a, a resonance capacitor 23, and an insulation signal receiving unit 25. The mounting components for the secondary side circuit 9 include a rectifier diode 26a and a smoothing capacitor. 20b etc. are mounted.

  The printed circuit board 6 uses an insertion board, but the primary circuit 8 is composed of lead type components (smoothing capacitor 20a, power MOSFET 21a, resonance capacitor 23) and surface mount components (insulated signal receiving unit 25). However, only the surface mount components (rectifier diode 26a, smoothing capacitor 20b) are used as the components of the secondary circuit 9. Thus, with respect to the secondary side circuit 9, there is no wiring pattern on the back side of the printed board, and insulation failure does not occur on the back side of the printed board.

  FIG. 6 is also a cross-sectional view of the substrate viewed from the lateral direction. In FIG. 6, the printed circuit board 6 is disposed on one surface of the insulating plate 3, and the components of the primary circuit 8 are mounted on the surface of the printed circuit board 6, and the transformer primary section 11 is mounted and fixed. Is done. Note that the printed circuit board 6 is installed on the insulating plate 3 at an appropriate interval h by the attachment component 100.

  On the other hand, the surface mounting substrate 30 is directly disposed on the other surface of the insulating plate 3. The components of the secondary circuit 9 are surface-mounted on the surface of the surface mounting substrate 30 and the transformer secondary portion 12 is also mounted. At this time, the transformer primary part 11 and the transformer secondary part 12 are arranged and fixed so as to face each other with the gap between the insulating plate 3 and the interval h.

  The insulating plate 3 is the same as or larger than the size of the bottom surface of the printed circuit board 6 and the surface mounting substrate 30. In the case of widening, it is possible to ensure a longer edge distance between the primary and secondary sides.

  On the other hand, the thickness of the insulating plate 3 is approximately 0.3 mm to 5.0 mm. The thicker the thickness, the higher the withstand voltage, and the parasitic capacitance can be reduced. On the other hand, the coupling between the primary and secondary is reduced, leading to a reduction in power supply efficiency. However, in the present invention, priority is given to improving the reliability and reducing the cost by reducing the withstand voltage and parasitic capacitance over the coupling between the primary and secondary.

  The printed circuit board 6 uses an insertion board, and the primary circuit 8 is composed of a lead type component and a surface mounting component. As the components of the secondary circuit 9, only surface mount components are used. Note that the printed circuit board 6 may also be configured using a surface mounting board.

  FIG. 7 is also a cross-sectional view of the substrate on which the circuit component of FIG. 3 or FIG. In FIG. 7, the primary circuit 8 is mounted on the left side of the printed circuit board 6. The transformer primary portion 11 is mounted and fixed on the back surface B side of the central portion of the printed circuit board 6. The transformer secondary part 12 is mounted and fixed at a position corresponding to the surface A side of the printed circuit board 6 with respect to the position where the transformer primary part 11 is mounted. A secondary circuit 9 is mounted on the right side from the position where the transformer secondary part 12 on the surface A side of the printed circuit board 6 is mounted.

  The printed circuit board 6 uses an insertion board, but the constituent parts of the primary circuit 8 are composed of lead type parts and surface mounting parts, and the constituent parts of the secondary circuit 9 are only surface mounting parts. Use. Thereby, there is no wiring pattern on the back surface B of the printed circuit board with respect to the secondary circuit 9, and it is possible to prevent the occurrence of insulation failure on the back surface B side of the printed circuit board.

  The board thickness of the printed circuit board 6 is approximately 0.3 mm to 2.4 mm. The thicker the plate, the higher the withstand voltage, and the parasitic capacitance can be reduced.

  According to the embodiment described above, the insulating transformer 19 reliably cuts off not only the primary winding and the secondary winding but also the primary side iron core and the secondary side iron core by the printed circuit board 6. Therefore, the primary winding and the secondary winding are reliably separated. In addition, the parasitic capacitance between the primary and secondary can be reduced by using an insulating material having a low dielectric constant as the material of the printed circuit board. Further, the breakdown voltage of the transformer can be improved by increasing the thickness of the printed circuit board 6, and at the same time, the parasitic capacitance between the primary and secondary can be reduced. As described above, in the present invention, an insulating transformer having a high withstand voltage can be obtained with a simple structure using a printed circuit board, so that the cost can be reduced.

  Next, forming the insulating transformer 19 shown in FIG. 1 or FIG. 2 by molding will be described with reference to FIGS.

  FIG. 8 is a sectional view of the insulating transformer 19. In the case of the insulating transformer shown in FIG. 1, the cores 1a and 1b are so-called pot-type ferrite cores having a circular shape, and have a cylindrical leg at the center of the circle and a cylindrical leg at the periphery, When viewed from the side, the inside has a shape that is recessed into a donut shape.

  Further, in the case of the insulating transformer of FIG. 2, the cores 1a and 1b are E-type ferrite cores and have legs at the center and the peripheral part, so that the shape between the legs is recessed. Therefore, since the cross-sectional shape is the same in both FIG. 1 and FIG. 2, in the following description, the case where the insulating transformer of FIG. 1 is used (the cores 1a and 1b are circular so-called pot type ferrite cores) will be described. .

  In the cross-sectional shape of FIG. 8, the primary winding 2 is wound in a spiral shape around a hollow portion with the center leg of the core 1 a as the center. Further, the secondary windings 4a and 4b are also wound around the hollow portion of the core 1b in the same spiral manner as the core 1a.

  Then, the core 1a and the core 1b housing the windings are opposed to each other while maintaining a predetermined distance H so that the coil surfaces face each other. Next, as shown, the portion 30 sandwiched between the cores 1a and 1b and the peripheral portion 40 of the cores 1a and 1b are filled with the insulating material 5 and hardened to form the insulating transformer 19. Needless to say, when the mold shown in FIG. 8 is formed, a mold for the placement, fixation, or resin filling of the core in a predetermined position is appropriately prepared.

  In this case, since the function of the insulating plate 3 in FIGS. 1 and 2 is achieved by the portion 30 sandwiched between the core 1a and the core 1b, the characteristics of the insulating material to be filled or the distance H at which the coil surfaces face each other is Determined from the point of view of insulation. Specifically, the insulating material 5 is an insulator, and a material such as a resin or ceramic having a relatively low dielectric constant, which can be freely deformed in the manufacturing process and has a characteristic of solidifying later. The parasitic capacitance can be reduced by selecting a material having a low dielectric constant value.

  The facing distance H between the core 1a and the core 1b is approximately 0.3 mm to 5.0 mm. The thicker the thickness, the higher the withstand voltage, and the parasitic capacitance can be reduced. In addition, about the material of core 1a, 1b, you may use other magnetic bodies, such as an amorphous.

  According to the present embodiment, the withstand voltage and the parasitic capacitance can be adjusted by the distance H between the cores 1a and 1b and the material of the insulating material. In addition to the insulation between the primary and secondary windings, the primary iron core and secondary iron core are separated so that the transformer structure can be simplified and the cost can be reduced. I can plan.

  In the example of FIG. 8, the insulating plate 3 is not prepared, and the resin 5 at the time of molding has the function of an insulating plate, but in the mold formation example of FIG. 9, between the opposing cores 1 a and 1 b, The insulating plate 3 is prepared from the beginning.

  The insulating plate 3 is a disk-shaped insulating material having substantially the same diameter as the cores 1a and 1b, and is arranged so that the core 1a and the core 1b face each other with their coil surfaces facing each other and the insulating plate 3 is sandwiched between them. Then, as shown in the figure, the peripheral portions 40 of the cores 1a and 1b are hardened with the insulating material 5 to form the insulating transformer 19.

  The insulating material 5 is an insulator, and a material such as a resin or ceramic having a relatively low dielectric constant, which can be freely deformed in the manufacturing process and has a characteristic of solidifying later. The parasitic capacitance can be reduced by selecting a material having a low dielectric constant value for the insulating plate 3 in particular. The facing distance between the core 1a and the core 1b is approximately 0.3 mm to 5.0 mm. The thicker the thickness, the higher the withstand voltage, and the parasitic capacitance can be reduced. For the core material, other magnetic materials such as amorphous may be used.

  According to the present embodiment, the withstand voltage and the parasitic capacitance can be adjusted by the material and thickness of the insulating plate 3. In addition to the insulation between the primary and secondary windings, the primary iron core and secondary iron core are separated so that the transformer structure can be simplified and the cost can be reduced. I can plan.

  Finally, a power supply device configured as a power module will be described with reference to FIGS. 10, 11, and 12. First, FIG. 10 is a block diagram of a power module using the insulating transformer 19 of this embodiment.

  In FIG. 10, the power module 13 includes two sets of power supply units 50 a and 50 b configured by an insulating transformer and its secondary circuit 9, and a gate circuit 60. Note that the primary side circuit 8 in FIG. 3 is not included in the modularization range here, so an appropriate primary side circuit can be applied. Since the gate circuit 60 is incorporated, control signal lines 61 and 62, a gate output terminal, and the like are installed.

  In this figure, there are transformer primary parts 11a and 11b, transformer secondary parts 12a and 12b, secondary side circuits 9a and 9b, drive circuits 16a and 16b, power devices 14a and 14b, and transformer primary parts 11a and 11b. Are connected in series. The transformer secondary section 12a is connected to the secondary circuit 9a, the secondary circuit 9a is connected to the drive circuit 16a, and the drive circuit 16a is connected between the gate and emitter of the power device 14a.

  Similarly, the transformer secondary section 12b is connected to the secondary side circuit 9b, the secondary side circuit 9b is connected to the drive circuit 16b, and the drive circuit 16b is connected between the gate and emitter of the power device 14b. Power devices 14a and 14b are connected in series.

  FIG. 11 is a diagram showing a cross-sectional structure of a power module to which the insulating transformer of the present invention is applied. In FIG. 11, the power module 13 is screwed onto the heat sink 15. Power devices 14a and 14b are mounted on the bottom surface of the power module. The printed circuit board 6 is mounted on the power devices 14a and 14b, and the secondary circuits 9a and 9b and the transformer secondary parts 12a and 12b are mounted on the printed circuit board 6 together with the drive circuits 16a and 16b. The upper portion of the printed circuit board 6 is filled with the filler 17, but the transformer primary portions 11 a and 11 b are mounted on the portions corresponding to the upper portions of the transformer secondary portions 12 a and 12 b with the filler 17 interposed therebetween.

  FIG. 12 is a circuit diagram of a power module for a power module using the insulating transformer of this embodiment. In FIG. 12, the DC power source 7 is connected to the primary circuit 8. The primary circuit 8 includes a smoothing capacitor 20a, power MOSFETs 21a and 21b connected in series, a drive circuit 22, a resonance capacitor 23, and a lossless snubber capacitor 24. A resonance capacitor is provided at the midpoint of the series of power MOSFETs 21a and 21b. 23 is connected.

  The source electrodes of the resonant capacitor 23 and the power MOSFET 21b are connected in series with the transformer primary parts 11a and 11b outside the primary circuit. The transformer primary parts 11a and 11b are magnetically coupled to the transformer secondary parts 12a and 12b inside the power module via the filler 17, as shown in FIG.

  The transformer secondary parts 12a and 12b each have a center tap configuration, and the transformer secondary part 12a is connected to rectifier diodes 26a and 26b in the secondary side circuit 9a. The transformer secondary unit 12b is connected to rectifier diodes 26c and 26d in the secondary side circuit 9b. The rectifier diodes 26a and 26b are connected to the smoothing capacitor 20b. The rectifier diodes 26c and 26d are connected to the smoothing capacitor 20c. The circuit of FIG. 12 does not have a feedback circuit unlike FIGS. Instead, constant voltage circuits 31a and 31b are provided.

  In FIG. 12, the drive circuit 22 generates a pulse having a constant frequency and a fixed pulse width, and sends a gate signal according to this pulse to the power MOSFETs 21a and 21b to switch the power MOSFETs 21a and 21b.

  The transformer primary part 11a and the transformer secondary part 12a, and the transformer primary part 11b and the transformer secondary part 12b are magnetically coupled via the filler 17, respectively. Since the iron core made of ferrite is separated by the filler 17, the leakage inductance is relatively larger than that of the conventional insulating transformer. Therefore, in the present invention, this leakage inductance is effectively used. That is, by driving the power MOSFETs 21a and 21b at a frequency higher than the resonance frequency of this circuit, a resonance current flows in the series resonance circuit formed by the leakage inductance and the resonance capacitor 24, and the transformer secondary parts 12a and 12b are passed through. Power is transmitted.

  In the secondary side circuit 9a, the high-frequency alternating current transmitted to the transformer secondary part is rectified by the rectifier diodes 26a and 26b and accumulated in the smoothing capacitor 20b. Similarly, in the secondary side circuit 9b, the high-frequency alternating current transmitted to the transformer secondary part is rectified by the rectifier diodes 26c and 26d and accumulated in the smoothing capacitor 20c. In this embodiment, since there is no feedback circuit, output voltage fluctuations due to load fluctuations, temperature changes, and the like are stabilized by the constant voltage circuits 31a and 31b. The drive circuits 16a and 16b obtain stable voltages by the constant voltage circuits 31a and 31b.

  Next, in FIG. 10, drive power of the power devices 14a and 14b is supplied from the secondary circuits 9a and 9b to the drive circuits 16a and 16b. On the other hand, drive signals for the power devices 14 a and 14 b are input from the outside of the power module 13. The power devices 14a and 14b are illustrated as examples of IGBTs and anti-parallel diodes, but may be power MOSFETs or SiC switching devices. As described above, in the present embodiment, the method of insulating between the primary and secondary of the insulating transformer for the power device driving power source by the filler in the power module is shown. This simplifies the structure of the isolation transformer of the power device drive power supply, enabling downsizing and cost reduction.

  Thus, in the present embodiment, the same number of insulated transformers (two sets) as the number of IGBTs (two) as power switching devices are mounted on the power module. Further, the primary side circuit necessary for exciting these insulating transformers may be one circuit as shown in FIG. When the number of IGBTs mounted on a power module increases to 4 or 6, it can be handled by increasing the number of transformer primary parts in Fig. 12 to 4 or 6 according to the number of IGBTs. It is possible to reduce the volume and cost of the power source for driving the power module.

  In addition, the primary and secondary transformers may be insulated by the filler 17 and may be insulated by a resin material that is a module constituent member.

  According to the present invention described above, it is possible to reduce the size and increase the reliability of a power supply device using an insulating transformer by suppressing the generation of noise current when a lightning surge occurs. In addition, the cost of the insulation transformer and the power supply device using the insulation transformer can be reduced. Furthermore, it has the effect of reducing the size and increasing the reliability of a power supply device using an insulating transformer. In addition to the insulation between the primary and secondary windings, the primary iron core and secondary iron core are separated from each other, so the transformer structure can be simplified and the cost can be reduced. Can be planned.

  The present invention can be applied to a gate drive power supply device used in a railway vehicle inverter, an industrial power supply device, and the like.

1a, 1b: Core 2: Primary winding 3: Insulating plates 4a, 4b: Secondary winding 5: Insulating material 6: Printed circuit board 7: DC power supply 8: Primary side circuits 9, 9a, 9b: Secondary side Circuits 10a, 10b: Loads 11, 11a, 11b: Transformer primary part 12, 12a, 12b: Transformer secondary part 13: Power module 14a, 14b: Power device 15: Heat sink 16a, 16b: Drive circuit 17: Filler 18 : Optical cable 19: Insulation transformers 20a, 20b, 20c: Smoothing capacitors 21a, 21b: Power MOSFET
22: Drive circuit 23: Resonance capacitor 24: Lossless snubber capacitor 25: Insulation signal receiving unit 26a, 26b: Rectifier diode 27: Output voltage error amplification circuit 28: Insulation signal transmission unit 29: Control circuit 30: Surface mount substrates 31a, 31b : Constant voltage circuit

Claims (15)

  A primary side iron core wound with a primary winding, a secondary side iron core wound with a secondary winding, and an insulator, the primary side iron core and the secondary side iron core However, the insulating transformer is fixed and arranged on an insulator so as to face each other with the insulator interposed therebetween. The insulation transformer according to claim 1,
The primary side iron core and the secondary side iron core are pot-type ferrite cores, and the primary winding and the secondary winding are respectively disposed in the openings of the core, and the openings are relative to each other. An insulating transformer, wherein the insulating transformers are opposed to each other with the insulator interposed therebetween. The insulation transformer according to claim 1,
2. The insulation transformer according to claim 1, wherein the primary iron core and the secondary iron core are E-type ferrite cores, and are opposed to each other with the insulator interposed therebetween so that legs of the cores face each other. The insulation transformer according to claim 1,
The insulator is composed of two insulators having a gap in the middle, with the primary iron core facing one insulator and the secondary iron core facing the other insulator with the insulator sandwiched therebetween. An insulating transformer characterized by being arranged at a position where The insulation transformer according to any one of claims 1 to 4,
An insulating transformer, wherein the insulator is a printed circuit board on which an electronic component is mounted.   The primary side iron core around which the primary winding is wound and the secondary side iron core around which the secondary winding is wound are arranged via a gap, and at least the gap is filled with an insulating resin. An insulating transformer, wherein the winding surfaces of the primary side iron core and the secondary side iron core winding are opposed to each other.   A primary side iron core around which the primary winding is wound and a secondary side iron core around which the secondary winding is wound are arranged via an insulator, and at least the periphery of the iron core is made of an insulating resin. An insulating transformer, wherein the insulating transformer is arranged so as to cover the winding surfaces of the primary side iron core and the secondary side iron core winding.   A primary side iron core wound with a primary winding, a secondary side iron core wound with a secondary winding, and an insulator, the primary side iron core and the secondary side iron core However, a circuit system that includes an insulating transformer fixed and arranged on the insulator so as to face each other with the insulator interposed therebetween, and the circuit system that excites the insulating transformer is a series resonance system that uses a leakage inductance of the insulating transformer. A featured power supply.   A primary side iron core around which the primary winding is wound, a secondary side iron core around which the secondary winding is wound, and an insulator, the primary side iron core and the secondary side iron core being An insulating transformer fixed and arranged on the insulator so as to face each other with the insulator interposed therebetween, a primary circuit connected to the primary winding of the insulating transformer, and the secondary winding of the insulating transformer And a secondary side circuit to be connected, wherein the insulating transformer is mounted on a printed circuit board together with circuit components constituting the primary side circuit and the secondary side circuit. The power supply device according to claim 9, wherein
The insulator of the insulation transformer is the printed circuit board, and the primary side iron core and the secondary side iron core are arranged on each surface of the printed circuit board, respectively. The power supply device according to claim 9, wherein
The insulator of the isolation transformer is arranged such that the insulator is fixed vertically on the printed circuit board, the primary iron core is adjacent to the primary circuit, and the secondary side A power supply device, wherein an iron core is disposed adjacent to the secondary circuit. The power supply device according to claim 9, wherein
The power supply apparatus according to claim 1, wherein the circuit components constituting the secondary circuit are surface-mounted on a printed board. In a power supply device incorporating at least one power switching device and its drive circuit,
An insulating transformer for supplying power to the drive circuit is incorporated, and the insulating transformer includes a primary iron core wound with a primary winding, and a secondary iron core wound with a secondary winding. The primary side iron core and the secondary side iron core are arranged so as to face each other with a filler filled on the drive circuit board interposed therebetween, and at least the primary side iron core is A power supply device fixed by a filler. The power supply device according to claim 13,
A power supply device characterized in that the number of mounted isolation transformers is the same as the number of power switching elements. The power supply device according to claim 13,
A power supply device characterized in that as many insulating transformers as the number of power switching elements are connected in series.

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