JP2014103752A - Switching power supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a switching power supply device capable of achieving a charging function by configuring a switching circuit for charging on only one winding side of a transformer.SOLUTION: The switching power supply device includes a switching circuit 30 for charging and a two-way DC-DC converter 40 as a switching circuit for boosting. The switching circuit 30 for charging is connected between a system power supply 50 and a first winding 21 of a transformer 20 and, when a power supply battery 60 is charged with the system power supply 50, supplies a current with a single polarity to the first winding 21 of the transformer 20. The two-way DC-DC converter 40 boosts a DC voltage of the power supply battery 60 by using a second winding 22 of the transformer 20 as a reactor for boosting.

Description

  The present invention relates to a switching power supply apparatus.

  In the voltage conversion device disclosed in Patent Document 1, a transformer connects a power supply battery and a system power supply in an electrically insulated state. The first bridge circuit is connected between the power battery and the transformer. The booster circuit uses the first winding of the transformer as a booster coil. The second bridge circuit is connected to the second winding of the transformer. When the DC voltage of the power supply battery is boosted by the booster circuit, the switching elements of the first bridge circuit and the switching elements of the second bridge circuit are controlled so that power is not supplied to the system power supply connection part, When charging the power battery by connecting the system power supply connection section to the system power supply, control is performed so that the booster circuit does not function.

JP 2008-31394 A

  In Patent Document 1, it is possible to realize a reduction in size and cost by integrating a boosting reactor and a charging transformer into one in a circuit having a boosting and charging function. At this time, in order to provide a charging function, it is necessary to synchronously control each bridge circuit connected to each winding in the transformer.

  An object of the present invention is to provide a switching power supply device that can have a charging function by forming a charging switching circuit only on one winding side of a transformer.

  In the first aspect of the present invention, the first winding is connected to the system power supply, the second winding is connected to the power supply battery, and the transformer connects the power supply battery and the system power supply in an electrically insulated state. The charging switching is connected between the system power supply and the first winding of the transformer, and supplies a single polarity current to the first winding of the transformer when the power supply battery is charged by the system power supply. The present invention includes a circuit and a boosting switching circuit that boosts a DC voltage of the power supply battery using the second winding of the transformer as a boosting reactor.

  According to the first aspect of the present invention, when the power supply battery is charged by the system power supply in the charging switching circuit, a single polarity current is supplied to the first winding of the transformer. As a result, the power supply battery is charged by the system power supply. In the step-up switching circuit, the DC voltage of the power supply battery is stepped up using the second winding of the transformer as the step-up reactor.

  Therefore, it is not necessary to provide a bridge circuit for each winding in the transformer to control the bridge circuit in order to provide a charging function, and only one of the windings of the transformer constitutes a charging switching circuit. Can be given.

  As described in claim 2, in the switching power supply device according to claim 1, the switching circuit for charging includes a reactor, a capacitor, and a switching element, and the switching element is turned on and off through the reactor. The capacitor is charged and when the current flowing through the reactor becomes zero, the capacitor is discharged, and the transformer is energized through the reactor, and when the current flowing through the reactor becomes zero, the reactor is turned on again. It is preferable to charge the capacitor.

  3. The switching power supply device according to claim 2, wherein the switching element includes a first switching element and a second switching element connected in series, and a third switching element connected in series. The capacitor includes one end connected between the first switching element and the second switching element, and the other end connected to the third switching element and the fourth switching element. One end of the reactor is connected to the first switching element and the third switching element, and the other end is connected to the first winding of the transformer. .

  According to the present invention, it is possible to configure a charging switching circuit only on one winding side of the transformer to have a charging function.

The circuit diagram of the switching power supply device in an embodiment. The time chart at the time of charging a power supply battery with a system power supply. The circuit diagram for operation | movement explanation at the time of charging a power supply battery with a system power supply. The circuit diagram for operation | movement explanation at the time of charging a power supply battery with a system power supply.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described with reference to the drawings.
As shown in FIG. 1, the switching power supply device 10 is a power supply device for a plug-in hybrid vehicle.

The switching power supply device 10 includes a transformer 20, a charging switching circuit 30, and a bidirectional DC / DC converter 40 as a boosting switching circuit.
The transformer 20 has a first winding 21 and a second winding 22. In the transformer 20, the first winding 21 is connected to the system power supply 50 via the charging switching circuit 30 and the AC / DC conversion circuit 80, and the second winding 22 is connected to the power supply battery 60. And the system power supply 50 are connected in an electrically insulated state.

  The charging switching circuit 30 includes a reactor 31, a capacitor 32, switching elements S1, S2, S3, S4, and a current sensor 33. As the switching elements S1, S2, S3, and S4, power elements such as IGBTs and MOSFETs are used.

  The first switching element S1 and the second switching element S2 are connected in series. Further, the third switching element S3 and the fourth switching element S4 are connected in series. The capacitor 32 has one end connected between the first switching element S1 and the second switching element S2 and the other end connected between the third switching element S3 and the fourth switching element S4. Yes. One end of the reactor 31 is connected to the first switching element S 1 and the third switching element S 3, and the other end of the reactor 31 is connected to one end of the first winding 21 of the transformer 20.

  The other end of the first winding 21 of the transformer 20 is connected to the fourth switching element S4 and the AC / DC conversion circuit 80. The AC / DC conversion circuit 80 is connected to the first switching element S1 and the fourth switching element S4. A system power supply 50 outside the vehicle is connected to the AC / DC conversion circuit 80. The system power supply 50 is connected to the AC / DC conversion circuit 80 by a plug or an outlet, and the AC / DC conversion circuit 80 converts alternating current into direct current and supplies it to the charging switching circuit 30.

  The current sensor 33 detects the current flowing through the reactor 31. Switches SW are arranged between one end of the reactor 31 and the first winding 21 of the transformer 20 and between the other end of the first winding 21 and the switching element S4 (and the AC / DC conversion circuit 80). ing. By closing the switch SW, the first winding 21 of the transformer 20 and the charging switching circuit 30 are connected.

  A bidirectional DC / DC converter 40 as a boosting switching circuit includes power transistors (IGBTs) Q1 and Q2 and a capacitor 41 as switching elements. As the power transistors Q1 and Q2, MOSFETs or the like may be used instead of the IGBTs.

  Power transistors (IGBT) Q1, Q2 are connected in series. One end of the second winding 22 of the transformer 20 is connected between power transistors (IGBT) Q1 and Q2. The other end of the second winding 22 of the transformer 20 is connected to the positive terminal of the power battery 60. A capacitor 41 is connected in parallel to the power transistors (IGBTs) Q1, Q2 connected in series. The negative terminal of the power battery 60 is connected between the power transistor Q2 and the capacitor 41. A diode D1 is connected in antiparallel to the power transistor Q1. A diode D2 is connected in antiparallel to the power transistor Q2. A motor generator (travel motor) 91 is connected to the power transistors (IGBTs) Q1, Q2 connected in series via an inverter 90.

  The power battery 60 is 200 volt specification. That is, the power supply battery 60 has an output voltage that is lower than a voltage (for example, 600 volts) for driving a vehicle running motor and higher than a voltage (for example, 12 volts or 42 volts) for driving an auxiliary machine of the vehicle. Specifically, a 200-volt type is used. A smoothing capacitor 61 is connected in parallel to the power battery 60.

  Then, bidirectional DC / DC converter 40 boosts the DC voltage of power supply battery 60 using second winding 22 of transformer 20 as a boosting reactor. Bidirectional DC / DC converter 40 steps down the DC voltage from inverter 90.

  Inverter 90 converts the DC voltage output from bidirectional DC / DC converter 40 into an AC voltage and supplies the AC voltage to motor generator 91. Further, the inverter 90 converts the alternating voltage generated in the motor generator 91 with the regenerative braking of the motor generator 91 or the alternating voltage generated when the motor generator 91 is driven by the engine and functions as a generator into a bidirectional DC / DC. It is applied (supplied) to the power battery 60 side through the DC converter 40. At this time, the bidirectional DC / DC converter 40 operates (functions) as a step-down circuit.

  The switching power supply device 10 includes a controller 70. The controller 70 controls on / off of the switching elements S1, S2, S3, and S4 of the charging switching circuit 30. Further, the controller 70 inputs a detection result of the current flowing from the current sensor 33 to the reactor 31. Thereby, the controller 70 can detect whether or not the current flowing through the reactor 31 has become zero. The controller 70 controls opening / closing of the switch SW. Specifically, the controller 70 closes the switch SW when the system battery 50 charges the power battery 60.

  Further, the controller 70 controls on / off of the power transistors (IGBTs) Q1, Q2 of the bidirectional DC / DC converter 40. As a result, the bidirectional DC / DC converter 40 performs a step-up operation or a step-down operation.

  The controller 70 is connected to a main control device (not shown), a sensor that detects the rotational speed of the motor generator 91, and the like. Controller 70 obtains information on the driving state of the vehicle from the main control device, and drives and controls motor generator 91 based on the information and sensor signal. At this time, the bidirectional DC / DC converter 40 is caused to function as a booster circuit. The controller 70 controls the motor generator 91 as a generator based on information from the main control device and sensor signals. At this time, the bidirectional DC / DC converter 40 is caused to function as a step-down circuit.

The controller 70 controls the charging switching circuit 30 to charge the power supply battery 60 with the system power supply 50 in the drive stop state of the motor generator 91.
Next, the operation of the switching power supply device 10 configured as described above will be described with reference to FIGS.

First, the case where the power supply battery 60 is charged using the system power supply 50 as a power supply will be described.
The plug is connected to an outlet of the system power supply 50 (for example, a household 100 volt outlet). Then, an AC voltage is supplied from the system power supply 50 to the AC / DC conversion circuit 80 via a plug. The AC / DC conversion circuit 80 converts the supplied AC voltage into a DC voltage. The converted DC voltage is supplied to the charging switching circuit 30.

  The switching elements S <b> 1 to S <b> 4 of the charging switching circuit 30 are switched by a control signal from the controller 70, whereby the power supply battery 60 is charged with the current induced in the second winding 22 of the transformer 20.

2, 3, and 4 are diagrams for explaining the operation when the power battery 60 is charged by the system power supply 50.
In the time chart of FIG. 2, in order from the top, the switching elements S1, S3 are turned on / off, the voltage applied between both terminals of the switching elements S1, S3, the switching elements S2, S4 are turned on / off, the switching elements S2, The voltage applied between both terminals of S4 is shown. Further below that, the voltage of the capacitor 32, the current flowing through the reactor 31, the voltage between both terminals of the first winding 21 of the transformer 20, the voltage between both terminals of the second winding 22 of the transformer 20, to the power battery 60 The charging current is shown.

  In FIG. 2, the switching elements S1 and S3 are turned on from the timing t1 to the timing t2. The switching elements S2 and S4 are turned on from the timing t2 to the timing t3.

  In the first on-period T1 in which the switching elements S1 and S3 are turned on, the voltage between both terminals of the switching elements S1 and S3 is zero. Further, in the second on period T2 in which the switching elements S2 and S4 are turned on, the voltage between both terminals of the switching elements S2 and S4 becomes zero.

  In the first on-period T1 in which the switching elements S1 and S3 in FIG. 2 are turned on, the switching element S1 → the capacitor 32 → the switching element S3 → the reactor from the AC / DC conversion circuit 80, as indicated by reference numeral I5 in FIG. A current flows through a path 31 → the first winding 21 of the transformer 20 → the AC / DC conversion circuit 80. The capacitor 32 is charged by this energization, and the voltage gradually increases. Further, a current flows through the power supply battery 60 through the second winding 22 of the transformer 20 and the diode D2 as indicated by reference numeral I6.

  When the current flowing through the reactor 31 becomes zero (timing t2 in FIG. 2), the controller 70 turns on the switching elements S2 and S4, assuming that the capacitor 32 has been charged. In the second on-period T2, as indicated by a symbol I7 in FIG. 4, the current flows from the capacitor 32 through the path of the switching element S2, the reactor 31, the first winding 21 of the transformer 20, the switching element S4, and the capacitor 32. Flows. In this way, the capacitor 32 is discharged, and the reactor 31 and the first winding 21 of the transformer 20 are energized. Further, a charging current flows through the power supply battery 60 through the second winding 22 of the transformer 20 and the diode D2 as indicated by reference numeral I8. As a result, the power supply battery 60 is charged by the system power supply 50.

  When the current flowing through the reactor 31 becomes zero (timing t3 in FIG. 2), the controller 70 turns on the switching elements S1 and S3 on the assumption that the discharge of the capacitor 32 is completed.

  This is repeated, and a single polarity current (positive half-wave current) is applied as a current flowing through the reactor 31. That is, the power supply battery 60 is charged with a single polarity current (positive half-wave current) induced in the second winding 22 of the transformer 20.

  In this way, the switching elements S1, S2, S3, S4 of the charging switching circuit 30 are turned on / off. With this operation, the capacitor 32 is charged via the reactor 31 and when the current flowing through the reactor 31 becomes zero, the capacitor 32 is discharged and the transformer 20 is energized via the reactor 31 and flows into the reactor 31. When the current becomes zero, the capacitor 32 is charged again via the reactor 31. As a result, a charging switching circuit can be configured only on the first winding 21 side of the transformer 20, and a single polarity current (positive half-wave current) can be generated to charge the power supply battery 60. In addition, since the charging current can be controlled by the first winding 21 of the transformer 20, control on the power source battery 60 side is not necessary. In this way, synchronous control with the bridge circuit on the power supply battery 60 side, which is one winding side of the transformer, and the circuit on the other winding side of the transformer is not required, so that cost reduction can be achieved.

  Next, in the powering mode in which the motor generator 91 is driven as a travel motor, that is, the DC voltage of the power supply battery 60 is boosted and supplied to the inverter 90 using the second winding 22 of the transformer 20 as a boosting reactor. The case will be described.

  The controller 70 controls the power transistors Q1 and Q2 of the bidirectional DC / DC converter 40. Bidirectional DC / DC converter 40 boosts the output voltage (200 volts) of power supply battery 60 to the drive voltage (600 volts) of motor generator 91.

  Specifically, the controller 70 in FIG. 1 switches the power transistor Q2 with the power transistor Q1 of the bidirectional DC / DC converter 40 serving as a boosting switching circuit turned off, and boosts the voltage with the on / off. At this time, the controller 70 performs duty control on the power transistor Q2 to adjust (match) the voltage.

  More specifically, current flows through the second winding 22 of the transformer 20 and the power transistor Q2, and energy is stored in the second winding 22. Next, when the power transistor Q <b> 2 is turned off, a current flows through the diode D <b> 1 with the energy stored in the second winding 22 being applied, and is supplied to the inverter 90. That is, with the on / off control of the power transistor Q2, the boosted power is supplied to the inverter 90 when the power transistor Q2 is switched from on to off. At this time, the second winding 22 of the transformer 20 is used as a boosting reactor of the boosting circuit.

  The boosted voltage is supplied to the inverter 90, converted into alternating current by the inverter 90, and the motor generator 91 is driven. That is, the inverter 90 converts the boosted DC voltage supplied from the bidirectional DC / DC converter 40 into AC having a frequency for driving the motor generator 91 at a target speed, and outputs the AC voltage. Then, the motor generator 91 is driven, and the vehicle travels at the target vehicle speed.

Next, a description will be given of a power generation mode or a regeneration mode in which the motor generator 91 is driven as a generator.
In the controller 70 of FIG. 1, the motor generator 91 is used as a generator to charge the power battery 60 with the electric power of the motor generator 91 or the electric power generated by regeneration.

  The controller 70 in FIG. 1 turns off the power transistor Q2, switches the power transistor Q1, and returns the regenerative energy to the power supply battery 60 by the step-down operation accompanying on / off. At this time, the controller 70 adjusts (adjusts) the voltage by duty-controlling the power transistor Q1.

  Specifically, based on a command signal from controller 70, inverter 90 is controlled to convert an AC voltage output from motor generator 91 into a DC voltage, and the DC voltage is transferred from inverter 90 to bidirectional DC / DC converter 40. Is output. In the bidirectional DC / DC converter 40, a current flows through the power transistor Q1 and the second winding 22 of the transformer 20, and energy is stored in the second winding 22. Next, when the power transistor Q1 is turned off, a current flows through the diode D2 in a state where the energy stored in the second winding 22 is applied and is supplied to the power battery 60. That is, according to the on / off control of the power transistor Q1, power is supplied to the power supply battery 60 when the power transistor Q1 is switched from on to off.

According to the above embodiment, the following effects can be obtained.
(1) The switching power supply device 10 includes a charging switching circuit 30 and a bidirectional DC / DC converter 40 as a boosting switching circuit. The charging switching circuit 30 is connected between the system power supply 50 and the first winding 21 of the transformer 20. When the power supply battery 60 is charged by the system power supply 50, a single polarity current is supplied to the first winding of the transformer 20. Supply to line 21. The bidirectional DC / DC converter 40 as a boosting switching circuit boosts the DC voltage of the power supply battery 60 using the second winding 22 of the transformer 20 as a boosting reactor.

  Therefore, it is not necessary to provide a bridge circuit for each of the windings 21 and 22 in the transformer 20 in order to provide a charging function, so that each bridge circuit does not need to be controlled synchronously, and only one winding 21 side of the transformer 20 is charged. Can be provided with a charging function.

  (2) Specifically, the charging switching circuit 30 includes a reactor 31, a capacitor 32, and switching elements S1, S2, S3, and S4. When the switching elements S1, S2, S3, and S4 are turned on / off, the capacitor 32 is charged via the reactor 31, and when the current flowing through the reactor 31 becomes zero, the capacitor 32 is discharged and the transformer 20 passes through the reactor 31. And the capacitor 32 is charged again via the reactor 31 when the current flowing through the reactor 31 becomes zero. As described above, the charging switching circuit 30 can be configured using the reactor 31, the capacitor 32, and the switching elements S1, S2, S3, and S4.

  (3) More specifically, the switching element includes a first switching element S1 and a second switching element S2 connected in series, and a third switching element S3 and a fourth switching element S4 connected in series. . The capacitor 32 has one end connected between the first switching element S1 and the second switching element S2 and the other end connected between the third switching element S3 and the fourth switching element S4. Yes. Reactor 31 has one end connected to first switching element S1 and third switching element S3 and the other end connected to first winding 21 of transformer 20.

Therefore, a single polarity current can be supplied to the first winding 21 of the transformer 20 by charging and discharging the capacitor 32.
The embodiment is not limited to the above, and may be embodied as follows, for example.

Although the bidirectional DC / DC converter 40 is used as a boosting switching circuit, it may be a boosting switching circuit that simply boosts.
-Although embodied in a vehicle power supply device, it is not limited to this.

  DESCRIPTION OF SYMBOLS 10 ... Switching power supply device, 21 ... 1st winding, 22 ... 2nd winding, 20 ... Transformer, 30 ... Charging switching circuit, 31 ... Reactor, 32 ... Capacitor, 40 ... Bidirectional DC as boosting switching circuit / DC converter, 50 ... system power supply, 60 ... power battery, S1 ... switching element, S2 ... switching element, S3 ... switching element, S4 ... switching element.

Claims (3)

A transformer having a first winding connected to a system power supply and a second winding connected to a power supply battery, and connecting the power supply battery and the system power supply in an electrically insulated state;
A charging switching circuit which is connected between the system power supply and the first winding of the transformer and supplies a single polarity current to the first winding of the transformer when the power supply battery is charged by the system power supply. When,
A boosting switching circuit that boosts the DC voltage of the power battery using the second winding of the transformer as a boosting reactor;
A switching power supply device comprising: The charging switching circuit includes a reactor, a capacitor, and a switching element. When the switching element is turned on / off, the charging circuit is charged via the reactor, and the capacitor is turned on when a current flowing through the reactor becomes zero. 2. The switching power supply according to claim 1, wherein the capacitor is charged again through the reactor when the transformer is discharged and the transformer is energized and the current flowing through the reactor becomes zero. apparatus. The switching element is
A first switching element and a second switching element connected in series; a third switching element and a fourth switching element connected in series;
The capacitor is
One end is connected between the first switching element and the second switching element and the other end is connected between the third switching element and the fourth switching element.
The reactor is
The switching power supply according to claim 2, wherein one end is connected to the first switching element and the third switching element, and the other end is connected to the first winding of the transformer.