JP5318150B2 - Switching power supply - Google Patents

Description

  The present invention relates to a switching power supply apparatus that cools a switching element, a transformer, a choke coil, and the like by a cooling water channel, and prevents switching between a plurality of transformers and a choke coil in a heat unbalanced state and can improve heat dissipation of each transformer. The present invention relates to a power supply device.

  Conventionally, as a switching power supply device for dropping a high-voltage DC voltage to a desired DC voltage, a DC input voltage is converted into a rectangular wave voltage by a switching element, and the converted rectangular wave voltage is applied to the primary winding of the transformer. There is a switching power supply device that obtains a desired DC voltage by rectifying and smoothing a rectangular wave voltage extracted by a secondary winding of a transformer with a circuit including a rectifier element, a choke coil, a capacitor, and the like.

  In particular, a switching power supply device mounted on a vehicle such as a hybrid vehicle or an electric vehicle, which has been attracting attention in recent years, uses a voltage of a high voltage battery reaching several hundred volts as 14 V, which has been adopted as a power supply voltage of a conventional vehicle. It steps down and supplies power to many electrical loads and lead batteries. Since the electrical load connected to the 14V system reaches hundreds of amperes, the heat generated from the switching element and the transformer of the switching power supply is large, and a large current flows through the secondary circuit by stepping down the transformer. The amount of heat generated by the element and choke coil increases.

  To solve such a problem, the primary side winding is constituted by a plurality of transformers, the primary windings of the transformers being connected in series, and the secondary windings being connected in series or in parallel. Is applied in accordance with the number of transformers, the leakage inductance of the transformer is reduced by the amount of the voltage drop, switching loss of the switching element is reduced, and heat generation is suppressed (for example, Patent Document 1). See).

JP 2008-178205 A

  However, since magnetic components such as switching elements and transformers constituting the switching power supply device generate considerable heat, they are usually fixed and installed in a metal casing provided with a water channel. Heat dissipation is performed by the housing. In this case, the water channel provided in the metal housing is generally laid out so as to pass directly under the heat generating part, and the water channel becomes complicated when the heat generating parts are scattered. Pressure loss will increase. In addition, as pressure loss increases, measures such as improving the performance of the cooling pump are required.

  For this reason, it is effective to configure the main circuit component of the switching power supply device on the linear cooling water passage with small pressure loss. However, in the case of a linear cooling water channel, when all the heat generating components are arranged directly above the cooling water channel, there is a problem that the shape of the switching power supply device becomes elongated, and the connection between the components becomes difficult. For this reason, in practice, a switching element having a large amount of heat generation has to be preferentially disposed on the cooling water channel, and heat-generating components such as a transformer and a choke coil have to be disposed in places other than the cooling water channel.

  Therefore, for example, when a plurality of transformers, a plurality of rectifier circuits, and a plurality of smoothing circuits are required as in Patent Document 1, the heat of the plurality of transformers and the plurality of choke coils becomes unbalanced. However, the heat dissipation of the resonance inductor deteriorates, the cooling condition of the cooling water passage becomes severe, and there is a problem that the degree of freedom in arranging the heat generating parts is reduced. In addition, the heat of a magnetic material such as a transformer and a choke coil is in an unbalanced state, so that, for example, the inductance is unbalanced due to the temperature characteristic of the magnetic permeability, so that the balance of the electric circuit of the converter cannot be secured, The wiring between the inverter circuit, the resonance inductor, and the transformer is complicated.

  Therefore, these components are placed on or near the linear cooling water channel as much as possible, and heat dissipation of a plurality of transformers and a plurality of choke coils is ensured, and a thermal unbalanced state of these magnetic components is prevented. Therefore, it is necessary to determine an arrangement that relaxes the cooling conditions as much as possible. If the thermal equilibrium state cannot be maintained, a cooling capacity for cooling the highest temperature portion of the transformer is required, and as a result, the heat dissipation is deteriorated. The present invention has been made in order to solve such a problem, while maintaining heat in a balanced state with heat generated by a plurality of transformers, the plurality of rectifier circuits, the plurality of choke coils, and the plurality of capacitors. The purpose is to achieve a rational arrangement for dissipating heat and to simplify the cooling system.

The switching power supply apparatus of the present invention includes an inverter circuit that includes a switching element and generates an AC voltage from a DC voltage, and an AC voltage output from the inverter circuit is applied to the primary winding, and a different AC voltage is applied to the secondary winding. A plurality of transformers that output to each other, a plurality of rectifier circuits that rectify an alternating voltage induced in a secondary winding of each transformer, a plurality of choke coils that smooth the output of the rectifier circuit, A plurality of capacitors for smoothing the ripple voltage waveform output from the rectifier circuit, the inverter circuit, the plurality of transformers, the plurality of rectifier circuits, the plurality of choke coils, and a metal housing for fixing the plurality of capacitors; provided in the metal housing, said plurality of transformers, the plurality of rectifier circuits, the plurality of choke coils, wherein the plurality of co In the switching power supply device that includes a single cooling water passage comprising a linear shape for dissipating heat generated by capacitors, as well as placing an inverter circuit and a rectifier circuit comprising at least the switching element immediately above the cooling water channel, said plurality The transformer is arranged parallel to the longitudinal direction of the cooling water channel.

  According to the present invention, the inverter circuit and the rectifier circuit including at least the switching element are arranged immediately above the cooling water channel, and the plurality of transformers are arranged parallel to each other in the longitudinal direction of the cooling water channel. It is possible to prevent the heat of at least the plurality of transformers from being in an unbalanced state. Moreover, since at least the heat dissipation of the transformer is improved, it is possible to relax the cooling conditions of the cooling water channel and to improve the degree of freedom in arranging the heat generating components.

It is a circuit block diagram for demonstrating an example of the switching power supply device of this invention. It is a top view for demonstrating the layout of the components of the switching power supply in Embodiment 1 of this invention. It is a top view for demonstrating the layout of the components of the switching power supply device in Embodiment 2 of this invention.

Embodiment 1 FIG.
Embodiment 1 of the present invention will be described below with reference to FIGS.
As a switching power supply device applied to the present invention, a circuit diagram of a center tap type synchronous rectification method, which is a general circuit method of an insulating switching power supply device, is shown in FIG. The center tap type synchronous rectification method is a kind of rectification circuit that can obtain a rectification waveform equivalent to that of a general full-wave rectification circuit, but is not limited thereto, and other rectification methods may be used. The center tap type synchronous rectification type isolated switching power supply device includes an inverter that converts direct current to alternating current, and a plurality of transformers that convert the rectangular wave voltage output from the inverter into different voltages according to the turns ratio. In general, the primary windings of the transformer are connected in series with each other, and the secondary windings of the transformer are connected in parallel with each other.

  In FIG. 1, reference numerals 101a and 101b denote input terminals for applying a DC voltage to the switching power supply, and a voltage higher than the output voltage of the switching power supply is applied. Reference numeral 102 denotes an inverter circuit for converting a DC voltage input to the input terminal 101 into an AC voltage, and generally includes a switching element such as a MOSFET. 103a and 103b are primary windings of the transformer 105 to which the rectangular wave AC voltage output from the inverter circuit 102 is applied. Here, the primary winding is divided into two transformers 105a and 105b. A voltage waveform close to a rectangular wave generated by switching the provided switching elements 102a to 102d is applied.

  Reference numeral 104 denotes a resonance inductor necessary for performing a zero volt switching operation (ZVS operation) in order to reduce the switching loss generated in the switching element of the inverter circuit 102. Reference numeral 106 denotes a transformer secondary winding to which a rectangular wave AC voltage converted to a different voltage level according to the turns ratio of the transformer is applied, and a magnetic body for electromagnetically coupling with the transformer primary winding 103. Each is wound around a core.

  Reference numerals 107a and 107b denote rectifier circuits for rectifying the AC voltage output from the transformer secondary windings 106a and 106b. In this embodiment, MOSFET elements for realizing synchronous rectification are used. Reference numerals 108a and 108b are choke coils for smoothing the ripple voltage waveforms rectified by the rectifier circuits 107a and 107b, respectively. Reference numerals 109a and 109b are capacitors for smoothing the ripple voltage waveforms rectified by the rectifier circuits 107a and 107b. is there. The choke coil 108 and the capacitor 109 constitute a smoothing circuit.

Reference numeral 110 denotes an output terminal for outputting the DC voltage obtained by the rectifier circuit and the smoothing circuit to the outside of the switching power supply device. Reference numeral 111 denotes a ground terminal, which is connected to a metal casing 201 of a switching power supply device that is used as a ground for a secondary circuit described later.
In this embodiment, since the ground of the secondary side circuit is in the conductive position with the metal casing, the output voltage is output between the output terminal 110 and the metal casing 201.

Next, FIG. 2 which shows the layout figure of each component of the center-tap type synchronous rectification type insulated switching power supply apparatus described in FIG. 2 that are the same as or equivalent to those in FIG.
201 is a metal housing for fixing the inverter circuit 102, the resonance inductor 104, the transformers 105a and 105b, the rectification circuits 107a and 107b, and the smoothing circuits 108a, 108b, 109a, and 109b, and 202 is the inverter circuit 102 and for resonance. The cooling water channel provided in the said metal housing | casing 201 in order to thermally radiate the heat | fever which generate | occur | produces with the inductor 104, transformer 105a, 105b, rectifier circuit 107a, 107b, smoothing circuit 108a, 108b, 109a, 109b is shown.

Reference numeral 203 denotes a substrate for mounting the switching elements included in the inverter circuit 102 and the rectifier circuits 107a and 107b, and a metal substrate provided with a metal base plate is used to ensure heat dissipation. In this embodiment, the heat generated in the switching element is larger than the heat generated in the other components, so that the heat is generated immediately above the cooling water channel 202.
Reference numeral 204 denotes a harness for connecting the inverter circuit 102 and the primary windings 103a and 103b of the transformers 105a and 105b. Although the harness is used in the present embodiment, it may be connected using a substrate wiring or a copper plate. Good.

  The inverter circuit 102 to which a DC voltage is applied from the input terminals 101a and 101b is usually mounted on a metal substrate 203 having a metallic base plate (not shown) in order to ensure heat dissipation. In this embodiment, an example in which the switching element is mounted on the metal substrate 203 is shown. However, the switching element is brought into contact with the housing 201 through an insulator to dissipate heat, and the wiring of the inverter circuit 102 is configured by a substrate or a copper plate. Alternatively, other methods may be used.

  The transformers 105a and 105b are arranged in parallel to the longitudinal direction of the cooling water channel 202, the distances from the cooling water channel 202 to the transformer are equal, and the longitudinal direction of the cooling water channel 202 and the longitudinal direction of the transformers 105a and 105b are parallel to each other. Arrange so that. Thereby, the heat | fever of a some transformer can be maintained in an equilibrium state, and the heat dissipation of a some transformer can be improved.

  The resonance inductor 104 is disposed between the plurality of transformers 105a and 105b so that the longitudinal direction of the cooling water channel 202 and the longitudinal direction of the resonance inductor 104 are parallel to each other. By arranging the resonance inductor 104 between the plurality of transformers 105a and 105b in this manner, wiring between the inverter circuit 102, the resonance inductor 104 and the transformer 105 is facilitated, and the heat dissipation of the resonance inductor is improved. To do.

  Like the inverter circuit 102, the rectifier circuits 107a and 107b are mounted on a metal substrate 203 having a metallic base plate so as to sandwich the inverter circuit 102 from both sides. In this embodiment, the switching element is mounted on the metal substrate. However, the switching element is brought into contact with the casing 201 to dissipate heat, and the wiring of the rectifier circuit is configured with a harness or a copper plate, or other techniques are used. Also good.

  Further, the plurality of choke coils 108a and 108b are arranged in parallel to the cooling water channel 202, the distances from the cooling water channel 202 are equal to each other, and the longitudinal direction of the cooling water channel 202 and the longitudinal direction of the plurality of choke coils 108a and 108b Are arranged in parallel. Thereby, the heat | fever of a some choke coil can be maintained in an equilibrium state, and the heat dissipation of a some choke coil can be improved.

  Capacitors 109a and 109b for smoothing the ripple voltage waveform generated in the rectifier circuit 209 are connected to the choke coils 108a and 108b on one side of the capacitors 109a and 109b and the ground terminal on the other side, as shown in the figure. 111 is connected to the housing 201 via The other output terminal 110 outputs the DC voltage obtained from the rectifier circuits 107a and 107b, choke coils 108a and 108b, and capacitors 109a and 109b to the outside of the switching power supply device.

Embodiment 2. FIG.
FIG. 3 is a top view for explaining the layout of components of the switching power supply according to Embodiment 2 of the present invention. In the figure, the same or corresponding parts as those in the first embodiment shown in FIG. 3 differs from FIG. 2 in the arrangement of transformers 105a and 105b, choke coils 108a and 108b, and capacitors 109a and 109b.

  That is, a plurality of transformers 105a and 105b, a plurality of choke coils 108a and 108b, and a plurality of capacitors 109a and 109b are arranged symmetrically with respect to each other with the cooling water channel 202 interposed therebetween, and the resonance inductor 104 is connected to the cooling water channel. It is arranged immediately above 202. Further, the longitudinal direction of the cooling water channel 202 and the longitudinal direction of the resonance inductor 104 and the plurality of choke coils 108a and 108b are arranged in parallel to each other, and the plurality of choke coils and the plurality of capacitors are The distances from the cooling water channels are equal to each other.

Even in such a configuration, similarly to the first embodiment, it is possible to prevent the heat of the plurality of transformers and the plurality of choke coils from being in an unbalanced state. In addition, compared to the first embodiment, a more complete left-right symmetrical arrangement with the cooling water channel as the center can be realized, and heat can be maintained in an equilibrium state in the entire power supply circuit. Can be improved.
In addition, since the heat dissipation of the transformer, choke coil, and resonance inductor is improved, there are merits such as relaxation of cooling conditions of the cooling water channel and improvement in the degree of freedom in the arrangement of the heat generating components. For example, since the heat dissipation of the transformer is improved, the transformer can be disposed at a location away from the cooling water channel, so that there is an advantage that a space between the cooling water channel and the transformer can be secured.

  Furthermore, since it is possible to prevent the heat of a magnetic material such as a transformer and a choke coil from being in an unbalanced state, it is possible to prevent the inductance from being unbalanced due to, for example, the temperature characteristic of the magnetic permeability. The degree of balance can be ensured. In addition, by arranging the resonance inductor between a plurality of transformers, wiring between the inverter circuit, the resonance inductor, and the transformer is facilitated.

101 input terminal, 102 inverter circuit, 104 resonant inductor,
103 primary winding, 105 transformer, 106 secondary winding,
107 rectifier circuit, 108 choke coil, 109 capacitor,
110 output terminal, 111 ground terminal, 201 metal housing,
202 cooling water channel, 203 metal substrate, 204 kernel.

Claims (7)

An inverter circuit that includes a switching element and generates an alternating voltage from a direct current voltage; a plurality of transformers in which the alternating voltage output from the inverter circuit is applied to the primary winding and a different alternating voltage is output to the secondary winding; A plurality of rectifier circuits each having a switching element for rectifying an AC voltage induced in the secondary winding of each transformer; a plurality of choke coils for smoothing the output of the rectifier circuit; and a ripple voltage output from the rectifier circuit A plurality of capacitors for smoothing the waveform, the inverter circuit, the plurality of transformers, the plurality of rectifier circuits, the plurality of choke coils, a metal casing for fixing the plurality of capacitors, and provided in the metal casing, wherein the plurality of transformers, the plurality of rectifier circuits, the plurality of choke coils, straight to dissipate the heat generated by the plurality of capacitors In the switching power supply device that includes a single cooling channel a shape, while placing an inverter circuit and a rectifier circuit comprising at least the switching element immediately above the cooling water channel, said plurality of transformers of the cooling water channel longitudinal direction The switching power supply device is arranged in parallel with the switching power supply device.   2. The switching power supply device according to claim 1, wherein the plurality of transformers are arranged such that distances from the cooling water channel are equal to each other, and a longitudinal direction of the cooling water channel and a longitudinal direction of the transformer are parallel to each other. .   The plurality of transformers are respectively disposed on one side of the cooling water channel, and a resonance inductor that is electrically inserted between the inverter circuit and the transformer and performs a zero-volt switching operation of the inverter circuit is interposed between the plurality of transformers. 2. The switching power supply device according to claim 1, wherein the plurality of choke coils and the plurality of capacitors are respectively disposed on the other side of the cooling water channel.   The plurality of transformers, the plurality of choke coils, and the plurality of capacitors are arranged symmetrically with respect to each other across the cooling water channel, and are electrically inserted between the inverter circuit and the transformer to perform zero-volt switching operation of the inverter circuit. The switching power supply according to claim 1, wherein the resonance inductor to be performed is disposed immediately above the cooling water channel.   5. The switching power supply device according to claim 3, wherein a longitudinal direction of the cooling water channel and a longitudinal direction of the resonance inductor are parallel to each other.   5. The switching power supply device according to claim 3, wherein the plurality of choke coils and the plurality of capacitors are arranged such that distances from the cooling water channel are equal to each other.   The switching power supply device according to claim 6, wherein a longitudinal direction of the cooling water channel and a longitudinal direction of the plurality of choke coils are parallel to each other.

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