JP5308682B2 - Bidirectional DC / DC converter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bidirectional DC/DC converter which corresponds to voltage that cannot be boosted or reduced only by a winding ratio, enables conversion into a prescribed voltage value, and allows easily miniaturization by reducing the number of components. <P>SOLUTION: The bidirectional DC/DC converter is provided with a first switch inserted between one end of primary winding of a transformer and a + terminal of first voltage, a second switch inserted between one end of primary winding and a - terminal of first voltage, a third switch inserted between the other end of primary winding and the + terminal of first voltage, a fourth switch inserted between the other end of primary winding and the - terminal of first voltage, a coil, a fifth switch inserted between one end of the coil and a + terminal of second voltage, a sixth switch inserted between one end of the coil and a - terminal of second voltage, a seventh switch inserted between one end of secondary winding and the other end of the coil, an eighth switch inserted between one end of secondary winding and the - terminal of second voltage, a ninth switch inserted between the other end of secondary winding and the other end of the coil and a tenth switch inserted between the other end of secondary winding and the - terminal of second voltage. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a bidirectional DC / DC converter, and more particularly to a bidirectional DC / DC converter that enables voltage transformation (step-down or step-up) to a predetermined output voltage over a wide input voltage range.

Usually, the DC / DC converter is configured to step down in one direction, that is, from a high voltage to a low voltage or from a low voltage to a high voltage.
However, some vehicles have two DC power supply systems that use batteries having different voltage values (high voltage side voltage and low voltage side voltage).

Therefore, in a vehicle that requires high efficiency, there is a movement to efficiently use limited energy by performing voltage conversion between two DC power supply systems, that is, low voltage to high voltage or high voltage side voltage to low voltage side voltage. It is increasing.
Here, when power is interchanged, generally, a configuration of a bidirectional DC / DC converter in which a direct current booster circuit and a direct current voltage stepdown circuit are arranged in parallel between direct current power supply systems and used appropriately. Is adopted (see, for example, Patent Document 1).
JP 2004-282828 A

However, in the bidirectional DC / DC converter disclosed in Patent Document 1, the conversion voltage of the bidirectional, particularly the step-up voltage is reduced during the step-down operation due to the turns ratio of the primary side and the secondary side of the transformer. There is a problem that the upper limit of the step-down voltage is limited by the voltage value.
In the conventional DC / DC converter, for example, when the input voltage of 100V-200V is stepped down to 10V-20V, that is, the turn ratio corresponding to the step-down, a voltage exceeding 10V to 200V is increased when boosting. Cannot be generated.
Conversely, if the input voltage of 10V-20V is boosted to 100V-200V, that is, the turn ratio corresponding to boosting, a voltage exceeding 100V to 10V cannot be generated when boosting.
Therefore, in the conventional example, when stepping down using the turn ratio set to the boosting ratio, in order to obtain a desired stepped down voltage, it is necessary to separately form a boosting circuit in parallel, increasing the number of parts, and There is a problem that the circuit scale becomes large.

  The present invention has been made in view of such circumstances, and it is possible to output a step-down voltage as a set voltage value even when a winding ratio set corresponding to a boost operation is set. In addition, even when the winding ratio set for the step-down operation is set, the upper limit value and the lower limit value of the step-down voltage or the boost voltage can be output as the set voltage value. Provided is a bidirectional DC / DC converter that can be widely set without being limited by the winding ratio, can reduce the number of parts compared to the conventional one, and can easily reduce the size of the converter circuit. For the purpose.

  The bidirectional DC / DC converter of the present invention is a bidirectional DC / DC converter that performs a voltage conversion operation between a first voltage and a second voltage, and includes a primary winding and a secondary winding. A transformer comprising: a first switch means interposed between one end of the primary winding and the + side terminal of the second voltage; the one end of the primary winding and the second voltage A second switch means interposed between a negative side terminal, a third switch means interposed between the other end of the primary winding and the positive side terminal of the second voltage, and the primary A fourth switch means interposed between the other end of the winding and the negative terminal of the second voltage; and provided between one end of the secondary winding and the positive terminal of the first voltage. Choke coil and fifth switch means interposed between one end of the choke coil and the positive terminal of the first voltage; Sixth switch means interposed between the one end of the choke coil and the negative terminal of the first voltage, and a seventh switch interposed between one end of the secondary winding and the other end of the choke coil. Switch means, an eighth switch means interposed between the one end of the secondary winding and the negative terminal of the first voltage, the other end of the secondary winding and the choke coil And a tenth switch means interposed between the other end of the secondary winding and the negative terminal of the first voltage. .

  The bidirectional DC / DC converter according to the present invention comprises a first control circuit for controlling the first to fourth switch means, and a diode connected in parallel to each of the seventh to tenth switch means. A first rectifier circuit connected to the secondary winding, and in the step-up operation, when the first voltage is a high voltage and the second voltage is a low voltage, the first control circuit Is configured to periodically control the first and third switch means to control connection between one end or the other end of the primary winding and the + side terminal of the second voltage, Further, the second and fourth switch means are periodically controlled to connect either one end or the other end of the primary winding to the negative terminal of the second voltage, and for each period. Push-pull operation so that the direction of the current flowing through the secondary winding is reversed. In this case, when the step-down voltage does not reach a preset voltage, the choke coil is controlled by turning on and off the sixth switch means with the first rectified voltage output from the first rectifier circuit. The step of boosting the first rectified voltage is performed, and the boosted voltage is output as a boosted voltage.

  In the bidirectional DC / DC converter according to the present invention, in the step-up operation, the first control circuit sets the on / off timing of the switches of the first and third switch means and the second and fourth switch means in phase. And the pulse width control, and the boosted voltage is controlled to be a preset voltage.

  The bidirectional DC / DC converter of the present invention comprises the second control circuit for controlling the seventh to tenth switch means and the diode connected in parallel to each of the first to fourth switch means. And a second rectifier circuit connected to the primary winding, and in the step-down operation, when the first voltage is a high voltage and the second voltage is a low voltage, the second control circuit Is configured to periodically control the seventh and ninth switch means to control connection between one end or the other end of the secondary winding and the other end of the choke coil, and The eighth and tenth switch means are periodically controlled to connect either one end or the other end of the secondary winding to the negative terminal of the first voltage, and for each period Push-pull so that the direction of current flowing through the primary winding is reversed Is created, the rectified voltage output from the second rectifier circuit and outputs a reduced voltage by smoothing

  The bidirectional DC / DC converter according to the present invention controls the seventh, eighth, ninth and tenth switching means so that a current continuously flows through the choke coil in the same direction during the step-down operation. It is characterized by that.

  In the bidirectional DC / DC converter according to the present invention, in the step-down operation, the step-down voltage is preset by the second control circuit controlling a duty ratio of a pulse for turning on and off the fifth switch means. It is characterized by controlling to be a voltage.

  In the bidirectional DC / DC converter according to the present invention, the first to fourth and seventh to tenth switching means are MOS transistors, and diodes connected in parallel are parasitic diodes of the MOS transistors. The first and second rectifier circuits are configured.

The bidirectional DC / DC converter of the present invention is a bidirectional DC / DC converter that performs a voltage conversion operation between a first voltage and a second voltage, and includes a first primary winding and A first transformer comprising a first secondary winding, a second transformer comprising a second primary winding and a second secondary winding, a third primary winding and a third 2 A third transformer composed of a secondary winding, an end of the second primary winding, an end of the third primary winding, and a positive terminal of the second voltage. Inserted between the other end of the second primary winding and the other end of the third primary winding and the negative terminal of the second voltage. A third switch interposed between the second switch means, the other end of the first primary winding and the one end of the second primary winding, and a positive terminal of the second voltage; Before the switch means A fourth switch means interposed between the other end of the first primary winding and one end of the second primary winding and the negative terminal of the second voltage; and the third Eleventh switch means interposed between the other end of the primary winding and one end of the first primary winding and the + side terminal of the second voltage, and the third 1 A twelfth switch means interposed between the other end of the secondary winding and one end of the first primary winding and the negative terminal of the second voltage; and A choke coil provided between one end and the + side terminal of the first voltage; a fifth switch means interposed between the one end of the choke coil and the + side terminal of the first voltage; and the choke coil. A sixth switch means interposed between the one end of the first voltage and the negative terminal of the first voltage, one end of the first secondary winding and the other end of the third primary winding. Seventh switch means inserted between the other end of the choke coil, one end of the first secondary winding and the other end of the third primary winding, and the first voltage An eighth switch means interposed between the negative terminal and the negative terminal;
Ninth switch means interposed between the other end of the first secondary winding and one end of the second secondary winding and the other end of the choke coil; and the first 2 A tenth switch means interposed between the other end of the secondary winding and one end of the second secondary winding and the negative terminal of the first voltage; and the second secondary winding. An eleventh switch means interposed between the other end of the wire and one end of the third secondary winding and the other end of the choke coil; the other end of the second secondary winding; It has a twelfth switch means interposed between one end of the third secondary winding and the negative terminal of the first voltage.

  As described above, according to the bidirectional DC / DC converter of the present invention, the winding ratio of the coil is set corresponding to the step-up operation from the low voltage side to the high voltage side, and the step-down from the high voltage to the low voltage is performed. In the operation, if the required voltage value cannot be obtained, it is possible to perform a boost operation using a choke coil, so that the generation range of both the boost voltage and the step-down voltage is compared with the conventional example by the boost and step-down voltage. The upper limit value and lower limit value of the generated voltage value can be set widely without being limited by the winding ratio.

  That is, according to the DC / DC converter of the present invention, as described above, when the stepped down voltage is less than the set voltage, the stepped down voltage is boosted to obtain a desired set voltage. Therefore, it is not necessary to provide a separate step-down circuit to deal with the step-down voltage that cannot be handled by the winding ratio. There is an effect that the number of points can be suppressed, and the reduction in size and cost can be realized.

Hereinafter, a bidirectional DC / DC converter according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration example of the embodiment.
In the present invention, as shown in FIG. 1, the voltage value decreases between one of the battery B1 having the low voltage VoL and the battery B2 having the high voltage VoH, while supplementing the energy from the other. It is a DC / DC converter used for suppressing a decrease in the power.
In this figure, the bidirectional DC / DC converter according to the present embodiment includes a transformer 1, a primary side orthogonal transform unit 2, a secondary side orthogonal transform unit 3, and a booster circuit 4.

With the above-described configuration, in the bidirectional DC / DC converter according to the present embodiment, in the voltage conversion (energy conversion) in the step-down process, the secondary side orthogonal transform unit 3 uses the DC high voltage VoH in the battery B2 as one end, single phase. Converting into a rectangular wave AC voltage, the primary side orthogonal transformation unit 2 rectifies the single-phase rectangular wave AC voltage and converts it into a DC low voltage VoL.
On the other hand, in the bidirectional DC / DC inverter, in the energy conversion of the step-down process, the primary side orthogonal transform unit 3 converts the DC low voltage VoL in the battery B1 into a single-phase rectangular wave AC voltage at one end, and the secondary voltage. The side orthogonal conversion unit 3 rectifies the single-phase rectangular wave AC voltage and converts it into a DC high voltage VoH. The switch means in the embodiment uses a MOS transistor. As a diode used for rectification in each orthogonal transform unit, a diode element connected in parallel to each MOS transistor may be used instead of the parasitic diode of the MOS transistor.

In FIG. 1, the primary side orthogonal transform unit 2 includes N-channel MOS transistors (hereinafter simply referred to as transistors) Q1, Q2, Q3, and Q4 and a first control circuit 5, and has an inverter configuration. .
The drains of the transistors Q1 and Q3 are connected to the + side terminal TVoL of the high voltage battery B1.
On the other hand, each of the transistors Q2 and Q4 has a source connected to the negative terminal TVoLL of the high voltage battery B1.
The source of the transistor Q1 is connected to the drain of the transistor Q2 at the connection point K1, and the source of the transistor Q3 is connected to the drain of the transistor Q4 at the connection point K2.

One terminal TA1 of the transformer 1 is connected to the connection point K1, and the other terminal TA2 of the transformer 1 is connected to the connection point K2.
The transistors Q1, Q2, Q3, and Q4 receive the control signals S1, S2, S3, and S4 from the first control circuit 5, respectively, with respect to their gates.
The first control circuit 5 outputs each control signal at the “H” level or “L” level, and the direction of the current flowing through the primary winding 1A of the transformer 1 is set to the opposite phase at a constant cycle. Control to be. As a result, a single-phase rectangular wave AC voltage is applied to the primary winding 1 </ b> A of the transformer 1.

The secondary side orthogonal transform unit 4 includes N-channel MOS transistors (hereinafter simply referred to as transistors) Q7, Q8, Q9, and Q10 and a second control circuit 6.
The transistor Q7 has a drain connected to the terminal Tc1 of the choke coil 7 and a source connected to the connection point P1.
The transistor Q9 has a drain connected to the terminal Tc1 of the choke coil 7 and a source connected to the connection point P2.
The transistor Q8 has a drain connected to the connection point P1, and a source connected to the negative terminal TvoHL of the low voltage battery B2.
The transistor Q10 has a drain connected to the connection point P2, and a source connected to the negative terminal TvoHL of the low voltage battery B2.

The connection point P1 is connected to one terminal TB1 of the secondary winding 1B of the transformer 1, and the connection point P2 is connected to the other terminal TB2 of the secondary winding 1B of the transformer 1.
In addition, control signals S7, S8, S9, and S10 are input to the gates of the transistors Q7, Q8, Q9, and Q10 from the second control circuit 6, respectively.
The second control circuit 6 outputs each control signal at the “H” level or the “L” level, and the direction of the current flowing through the secondary winding 1B of the transformer 1 is reversed with a constant period. Control to be. As a result, a single-phase rectangular wave AC voltage is applied to the secondary winding 1B of the transformer 1.

The booster circuit 4 includes the choke coil 7 and an n-channel MOS transistor (hereinafter simply referred to as transistor) Q6.
The choke coil 7 has one terminal Tc1 connected to the drains of the transistors Q7 and Q9, and the other terminal Tc2 connected to the drain of the transistor Q6.
The source of the transistor Q6 is connected to the negative terminal TvoHL of the high voltage battery B2.
The output terminal of the booster circuit 4, that is, the terminal Tc2 of the choke coil 7, is connected to the source of an n-channel MOS transistor (hereinafter simply referred to as transistor) Q5.
The drain of the transistor Q5 is connected to the positive terminal TvoH of the high voltage battery B2.

As described above, in the primary side orthogonal transform unit 2, the structure of the composite switch including the transistors Q1 to Q4 has an inverter configuration that generates one single-phase rectangular wave AC voltage.
At elevated pressure operation, corresponding to the single-phase rectangular wave alternating voltage, the secondary side orthogonal transforming section 3, the current flowing through the primary winding 1A, a voltage induced by reverse phase secondary winding 1B Single-phase full-wave rectification is performed to generate a high voltage VoH.
The secondary side orthogonal transform unit 3 performs a rectification operation of a single-phase rectangular wave AC voltage induced in the secondary winding 1B by both-wave rectification by the parasitic diodes D7 and D9 of the transistors Q7 and Q9 described above.
Here, in the step-down operation, instead of performing the two-wave rectification using the diode as described above, the second control circuit 6 turns on / off the transistors Q7 to Q10 in synchronization with the above-described switching of the transistors Q1 to Q4. The single-phase rectangular wave AC voltage induced in the secondary winding 1B may be rectified by synchronous rectification.

In the boosting operation described above, the first control circuit 5 controls the transistor Q1 corresponding to the connection point K1 with respect to the phase of the control signals S3 and S4 applied to the gates of the transistors Q3 and Q4 corresponding to the connection point K2. The voltage value of the boosted high voltage is controlled by changing the phases of the control signals S1 and S2 applied to the gates of Q2 and Q2. Here, the periods when the control signals S3 and S4 and the control signals S1 and S2 become the “H” level and the “L” level have the same length.
Also, instead of the above-described phase control, the pulse width of the control signals S1, S2, S3, and S4 is adjusted, the on / off time of the transistors Q1 to Q4 is controlled, and the PWM (Pulse) that controls the voltage value of the step-down voltage is controlled. Width Modulation control may be used.

At this time, the turns ratio 1: n (the number of primary windings: the number of secondary windings) of the transformer 1 is set corresponding to the step-up from the high voltage (secondary side) to the low voltage (primary side). For example, when used in a range where the low voltage side is 10V to 20V and the high voltage side is 100V to 200V, when the high voltage is 100V, the turn ratio can be 1:10. Become.
On the contrary, when the step-down operation is performed from the low voltage to the high voltage, when the turn ratio is 1:10 from the low voltage of 10V, the voltage is only 100V, and the voltage set as 200V is not generated.
For this reason, in this embodiment, even if control (phase control, PWM control, or the like) is performed so that the boosted voltage becomes the maximum value by phase control in the primary side orthogonal transform circuit 2 in the step-down operation, When the boosted voltage output from the conversion circuit 3 does not reach the set voltage, the boosted voltage output from the secondary side orthogonal transform circuit 3 is boosted by the booster circuit 4, and the boosted voltage of the preset voltage is set. Is generated.

On the other hand, in the secondary side orthogonal transform unit 3, the structure of the composite switch including the transistors Q7 to Q10 has an inverter configuration that generates one single-phase rectangular wave AC voltage.
In the step-down operation, corresponding to the single-phase rectangular wave AC voltage, the primary side orthogonal transform unit 2 simply applies a voltage induced in the primary winding 1A in the reverse phase by the current flowing through the secondary winding 1B. Phase full-wave rectification is performed to generate a low voltage VoL.
The primary side orthogonal transform unit 2 performs a rectification operation of a single-phase rectangular wave AC voltage induced in the primary winding 1A by the both-wave rectification by the parasitic diodes D1 and D3 of the transistors Q1 and Q3 described above.
Here, in the boosting operation, instead of performing the two-wave rectification using the diode as described above, the first control circuit 5 turns on / off the transistors Q1 to Q4 in synchronization with the switching described above of the transistors Q7 to Q10. The single-phase rectangular wave AC voltage induced in the primary winding 1A may be rectified by synchronous rectification.

In the step-down operation described above, the second control circuit 6 changes the duty ratio of the control signal S5 applied to the gate of the transistor Q5 by control and adjusts the amount of electric energy supplied to the choke coil 7, thereby reducing the step-down operation. Controls the voltage value of the low voltage that is generated. Here, the periods when the control signals S7, S8, S9, and S10 are at the “H” level and “L” level have the same length (the duty ratio is 1: 1).
Details of the timing of the control signals S7, S8, S9, and S10 for performing on / off control of the transistors Q7 to Q10 in the step-down operation in the present embodiment will be described later.

  Next, the step-up operation by the bidirectional DC / DC converter according to the present embodiment will be described with reference to FIGS. FIG. 3 is a timing chart for explaining a step-up operation from a low voltage to a high voltage by the bidirectional DC / DC converter according to the present embodiment. Here, the step-up process from a low voltage to a high voltage refers to a conversion process from a voltage of about 10 V to a voltage of about several hundred volts, for example. The primary-side direct conversion unit 2 performs phase control boosting processing, and the secondary-side direct conversion unit 3 performs both-wave rectification on the single-phase rectangular wave AC voltage induced in the primary winding 1B, thereby generating a high voltage. Is generated. At this time, the second control circuit 6 outputs “L” level control signals S7 to S10 to the transistors Q7 to Q10. For this reason, the transistors Q7 to Q10 are all turned off. The control signal S5 of “L” level is also input to the gate of the transistor Q5, and the transistor Q5 is turned off.

Note that FIG. 2 shows a configuration in which a load is inserted between the + side terminal TVoH and the − side terminal TVoHL instead of the battery B2 in order to perform a boosting operation, and the battery B1 having a low voltage VoL that complements the energy is primary. It is connected to the side conversion unit 2.
In the following description, the rectification operation performs both-wave rectification of the single-phase rectangular wave AC voltage induced in the secondary winding 1B in the double-wave rectification configuration of the diodes D7 to D10. Further, as described above, the rectification operation may be performed by a method of rectifying the single-phase rectangular wave AC voltage induced in the secondary winding 1A by synchronous rectification. Here, the number of primary windings: the number of secondary windings = 1: N.
In the timing chart of FIG. 3 used for the following description, a switching cycle for turning on / off the transistors Q1 and Q4 is defined as a cycle T1, and a switching cycle for turning on / off the transistors Q3 and Q2 is defined as a cycle T2. Let ΔT be the phase shift from T2.

<When the phases of the period T1 and the period T2 are shifted by 180 ° (= ΔT): FIG. 3A>
At time t1, the first control circuit 5 changes the control signal S1 and the control signal S4 from the “L” level to the “H” level, and changes the control signal S2 and the control signal S3 from the “H” level to the “L” level. To change.
Due to the change in the control signal, the transistors Q1 and Q4 are turned on, while the transistors Q2 and Q3 are turned off.
As a result, a current i1F (terminal TA1 → terminal TA2) flows through the primary winding 1A, thereby inducing a voltage of N · VoL between the terminals TB1 and TB2 of the winding 1B.
Here, the voltage N · VoL induced in the winding 1B is output via the diode D7 to the + side terminal TVoH via the choke coil 7 and the parasitic diode D5 of the transistor Q5.

At time t2, the first control circuit 5 changes the control signals S1 and S4 from the “H” level to the “L” level, and the control signals S2 and S3 from the “L” level to the “H” level.
Thereby, the transistors Q1 and Q4 are turned off, and the transistors Q2 and Q3 are turned off.
When a current i1B (terminal TA2 → terminal TA1) flows through the primary winding 1A, a voltage of N · VoL is induced between the terminals TB2 and TB1 of the winding 1B.
Here, the voltage N · VoL induced in the winding 1B is output via the diode D9 to the positive terminal TVOH via the choke coil 7 and the parasitic diode D5 of the transistor Q5.

The above-described processes at times t1 and t2 are repeated thereafter, and the boosting process is performed. When the phases of the period T1 and the period T2 are different from each other by 180 °, the boosted voltage is always induced in the transformer 1B, and the maximum voltage value obtained from the turns ratio of the transformer 1 even after smoothing by the choke coil 7 N · VoL is obtained as the boosted voltage.
The boosted high-voltage power supply signal is smoothed by a smoothing circuit composed of the choke coil 7 and the capacitor 6 and is output from the + side terminal TVoH as a constant high voltage VoH.

However, in the above-described boosting process in which the phases of the periods T1 and T2 are different from each other by 180 °, when the preset boosted voltage is not reached, the transistor Q6 is turned on / off to perform a boosting operation using the choke coil 2. The voltage rectified by the diodes D7 and D9 of the secondary direct conversion unit 3 is boosted, and the boosted voltage is output as a boosted voltage to the + side terminal TVoH via the diode D5.
The second control circuit 6 sets the control signal S6 to the “H” level to turn on the transistor Q6. The first control circuit 5 controls the control signals S1 and S4 and the control signals S2 and S3, respectively. Synchronize with the timing of the “H” level.

The voltage value of the boosted boost voltage, the second control circuit 6, the width or adjusting the duty of the control signal S6 for turning on and off the transistor Q6, or fixing the duty to (boosted voltage is boosted to the maximum To be fixed).
Further, the first control circuit 5 adjusts the phases of the periods T1 and T2 of the control signals S1 to S4 for controlling the primary side orthogonal transform unit 2 as described later, and the boosted voltage to be boosted is set in advance. You may adjust so that it may become the set voltage.

<When the phases of the period T1 and the period T2 are shifted by 90 ° (= ΔT): FIG. 3B>
At time t1, the first control circuit 5 changes the control signal S1 and the control signal S4 from the “L” level to the “H” level, and maintains the control signal S2 and the control signal S3 at the “L” level. .
Then, the transistors Q1 and Q4 change from off to on, and the transistors Q2 and Q3 remain off.
As a result, a current i1F flows in the primary winding 1A of the transformer 1, and a voltage of N · VoL is induced between the terminals TB1 and TB2 of the secondary winding 1B.

Next, at time t12, the first control circuit 5 keeps the control signals S1 and S4 at the “H” level and changes the control signals S2 and S3 from the “L” level to the “H” level.
As a result, all of the transistors Q1 to Q4 are turned on, the connection points K1 and K2 are set to the “L” level, the terminals TA1 and TA2 of the primary winding 1A of the transformer 1 have the same potential, and no current flows. No voltage is induced in the secondary winding 1B.

Next, at time t2, the first control circuit 5 changes the control signals S1 and S4 from the “H” level to the “L” level, and maintains the control signals S2 and S3 at the “H” level.
Then, the transistors Q1 and Q4 shift from on to off, and the transistors Q2 and Q3 remain on.
As a result, a current i1B flows through the primary winding 1A of the transformer 1, and a voltage of N · VoL is induced between the terminals TB2 and TB1 of the secondary winding 1B.

Next, at time t22, the first control circuit 5 keeps the control signals S1 and S4 at the “L” level and changes the control signals S2 and S3 from the “H” level to the “L” level.
As a result, all of the transistors Q1 to Q4 are turned off, the connection points K1 and K2 are in a floating state (a state in which they are floated without being electrically connected to any of them), and the terminal TA1 of the primary winding 1A of the transformer 1 and Since TA2 becomes the same potential and no current flows, no voltage is induced in the secondary winding 1B.

Thereafter, the processes from t1 to t22 described above are repeated after time t4.
And when the period of the period T1 and T2 mentioned above has shifted | deviated 90 degree | times, compared with the case where the phase of the period T1 and T2 has shifted | deviated 180 degree | times, in the secondary winding 1B of the transformer 1, A voltage of N · VoL is generated.
When the N · VoL with a duty of 50% is input to the choke coil 7 as a single-phase rectangular wave AC voltage, the input single-phase rectangular wave AC voltage is smoothed by the choke coil 7, and a predetermined step-down voltage is obtained. It is output to the + side terminal TVoH via the diode D5.
Therefore, the voltage value of the boosted voltage output to the + side terminal TVoH is adjusted by controlling the phase with the periods T1 and T2.
As described above, the process of boosting the voltage from the low voltage to the high voltage is performed by the push-pull operation in the transformer 1.

As described in FIGS. 3A and 3B, the phase of the change in the signal level of the control signal S2 and the control signal S3 is different from the phase of the change in the signal level of the control signal S1 and the control signal S4. By changing (adjusting) the deviation, the period during which current flows in the primary winding 1A is controlled, the pulse width of the single-phase rectangular wave AC voltage induced in the secondary winding 1B is controlled, and the high voltage VoH Can be arbitrarily controlled.
Further, in the primary side orthogonal transforming unit 2, the pulse width of the control signals S1 to S4 is adjusted, that is, each of the transistors Q1 to Q4 is not controlled by controlling the period in which the current flows through the primary side winding 1A by phase control. By controlling the pulse width for controlling the pulse width to turn on the current, the period of current flow through the primary winding 1A is controlled to control the pulse width of the induced single-phase rectangular wave AC voltage. good.

Next, with reference to FIGS. 4 and 17, for explaining the step-down operation by the bi-directional DC / DC converter according to the present embodiment. FIG. 4 is a block diagram showing a configuration example of the present embodiment for explaining the step-down operation. 17 is a timing chart for explaining the descending pressure operation of the high voltage to low voltage by the bidirectional DC / DC converter according to the present embodiment. Here, the buck process from a high voltage to a low voltage, for example, refers to the conversion from voltage of about 100~200V to 10 number V voltage of about. In the secondary side orthogonal transform unit 3 performs a buck processing of the phase control, the primary side orthogonal transformation unit 2, wave rectification with respect to the single-phase rectangular wave alternating electric current voltage induced in the secondary winding 1A is performed, the low A voltage is generated.

  At this time, the first control circuit 5 outputs “L” level control signals S1 to S4 to the transistors Q1 to Q4. For this reason, the transistors Q1 to Q4 are all turned off. On the other hand, the second control circuit 6 outputs the control signal S6 at the “L” level. As a result, the control signal S6 of “L” level is applied to the gate, so that the transistor Q6 is turned off. The second control circuit 6 outputs a control signal S5 of “H” level of a periodic pulse to the gate of the transistor Q5. By changing the duty of this pulse, the electric energy supplied to the choke coil 7 is controlled, and the step-down voltage is adjusted.

4 shows a configuration in which a load is inserted between the + side terminal TVoH and the − side terminal TVoHL instead of the battery B1 in order to perform the step-down operation, and the battery B2 having a low voltage VoL that supplements energy is secondary. It is connected to the side conversion unit 3.
In the following description, the rectification operation performs both-wave rectification of the single-phase rectangular wave AC voltage induced in the primary winding 1A in the double-wave rectification configuration of the diodes D1 to D4. Further, as described above, the rectification operation may be performed by a method of rectifying the single-phase rectangular wave AC voltage induced in the primary winding 1A by synchronous rectification. Here, the number of primary windings: the number of secondary windings = 1: N.
In FIG. 5 to FIG. 16 used for the following description of the step-down operation, the switching cycle for turning on / off the transistors Q7, Q8, Q9 and Q10 is shown in the timing chart of FIG.

FIG. 5 shows an initial state, in which the transistors Q7 and Q10 are in the on state, and the transistors Q5, Q6, Q8 and Q9 are started from the off state, where the second control circuit 6 applies to the gate of the transistor Q5. The transistor Q5 is turned on by changing the control signal S5 from the “L” level to the “H” level.
As a result, a current i2F (terminal TB1 → terminal TB2) flows through the secondary winding 1B through the transistors Q5 and Q7, and a voltage of (1 / N) · VoH is induced between the terminals TA1 and TA2 of the winding 1A. The
Here, the voltage (1 / N) · VoH induced in the winding 1A is output to the positive terminal TVoL of the battery B1 via the diodes D4 and D1.

Next, in FIG. 6, the second control circuit 6 changes the control signal S5 applied to the gate of the transistor Q5 from the “H” level to the “L” level, whereby the transistor Q5 is turned off. As a result, the current i2F flowing through the choke coil 7 through the transistor Q7, the secondary winding 1B, and the transistor Q10 flows through the diode D6.
Even at this time, a voltage of (1 / N) · VoH is induced between the terminals TA1 and TA2 of the winding 1A, and this voltage (1 / N) · VoH is connected to the positive side of the battery B1 via the diodes D4 and D1. Output to terminal TVoL.

Next, in FIG. 7, the control signal S9 applied to the gate of the transistor Q9 by the second control circuit 6 is changed from the “L” level to the “H” level, whereby the transistor Q9 is turned on. Thereby, the parallel connection of the transistors Q7 and Q9, the state where the current i2F flowing through the choke coil 7 through the secondary winding 1B and the transistor 10 flows through the diode D6 is continued.
Even at this time, a voltage of (1 / N) · VoH is induced between the terminals TA1 and TA2 of the winding 1A, and this voltage (1 / N) · VoH is connected to the positive side of the battery B1 via the diodes D4 and D1. Output to terminal TVoL.

Next, in FIG. 8, the control signal S7 applied to the gate of the transistor Q7 by the second control circuit 6 is changed from the “H” level to the “L” level, whereby the transistor Q7 is turned off. As a result, the state in which the current i2F flowing through the choke coil 7 via the transistor Q9 and the transistor 10 flows via the diode D6 is continued.
At this time, since no current flows through the winding 1A, no voltage is induced between the terminals TA1 and TA2, and no voltage for charging is output to the positive terminal TVoL of the battery B1.

Next, in FIG. 9, the control signal S8 applied to the gate of the transistor Q8 by the second control circuit 6 is changed from the “L” level to the “H” level, whereby the transistor Q8 is turned on. However, since no current path flows into the transistor Q8, the current i2F flowing through the choke coil 7 through the transistors Q9 and 10 continues to flow through the diode D6.
At this time, since no current flows through the winding 1A, no voltage is induced between the terminals TA1 and TA2, and no voltage for charging is output to the positive terminal TVoL of the battery B1.

Next, in FIG. 10, the control signal S10 applied to the gate of the transistor Q10 by the second control circuit 6 is changed from the “H” level to the “L” level, whereby the transistor Q10 is turned off. As a result, the current i2B (terminal TB2 → terminal TB1) flows through the secondary winding 1B via the transistors Q9 and Q8, and a voltage of (1 / N) · VoH is induced between the terminals TA2 and TA1 of the winding 1A. Is done.
Here, the voltage (1 / N) · VoH induced in the winding 1A is output to the positive terminal TVoL of the battery B1 via the diodes D2 and D3.

Next, in FIG. 11, the second control circuit 6 changes the control signal S5 applied to the gate of the transistor Q5 from the “L” level to the “H” level, so that the transistor Q5 is turned on.
As a result, a current i2B (terminal TB2 → terminal TB1) flows through the secondary winding 1B via the transistors Q5, Q9 and Q8, and a voltage of (1 / N) · VoH is applied between the terminals TA2 and TA1 of the winding 1A. Induced.
Here, the voltage (1 / N) · VoH induced in the winding 1A is output to the positive terminal TVoL of the battery B1 via the diodes D2 and D3.

Next, in FIG. 12, the second control circuit 6 changes the control signal S5 applied to the gate of the transistor Q5 from the “H” level to the “L” level, whereby the transistor Q5 is turned off. As a result, the current i2B flowing through the choke coil 7 through the transistor Q10, the secondary winding 1B, and the transistor Q8 flows through the diode D6.
Even at this time, a voltage of (1 / N) · VoH is induced between the terminals TA2 and TA1 of the winding 1A, and this voltage (1 / N) · VoH is connected to the positive side of the battery B1 via the diodes D2 and D3. Output to terminal TVoL.

Next, in FIG. 13, the control signal S10 applied to the gate of the transistor Q10 by the second control circuit 6 is changed from the “L” level to the “H” level, whereby the transistor Q10 is turned on. Thus, the parallel connection of the transistors Q8 and Q10 and the state in which the current i2B flowing through the choke coil 7 through the secondary winding 1B and the transistor 9 flows through the diode D6 are continued.
Even at this time, a voltage of (1 / N) · VoH is induced between the terminals TA2 and TA1 of the winding 1A, and this voltage (1 / N) · VoH is connected to the positive side of the battery B1 via the diodes D2 and D3. Output to terminal TVoL.

Next, in FIG. 14, the control signal S8 applied to the gate of the transistor Q8 by the second control circuit 6 is changed from the “H” level to the “L” level, whereby the transistor Q8 is turned off. As a result, the state in which the current i2B flowing through the choke coil 7 via the transistor Q9 and the transistor 10 flows via the diode D6 is continued.
At this time, since no current flows through the winding 1A, no voltage is induced between the terminals TA2 and TA1, and no voltage for charging is output to the positive terminal TVoL of the battery B1.

Next, in FIG. 15, the control signal S7 applied to the gate of the transistor Q7 by the second control circuit 6 is changed from “L” level to “H” level, whereby the transistor Q7 is turned on. However, since no current path flows into the transistor Q7, the current i2B flowing through the choke coil 7 through the transistors Q9 and 10 continues to flow through the diode D6.
At this time, since no current flows through the winding 1A, no voltage is induced between the terminals A2 and TA1, and no voltage for charging is output to the positive terminal TVoL of the battery B1.

Next, in FIG. 16, the control signal S9 applied to the gate of the transistor Q9 by the second control circuit 6 is changed from the “H” level to the “L” level, whereby the transistor Q9 is turned off. As a result, the current i2F (terminal TB1 → terminal TB2) flows through the secondary winding 1B via the transistors Q7 and Q10, and a voltage of (1 / N) · VoH is induced between the terminals TA1 and TA2 of the winding 1A. Is done.
Here, the voltage (1 / N) · VoH induced in the winding 1A is output to the positive terminal TVoL of the battery B1 via the diodes D4 and D1.

And it returns to the state of FIG. 5, the process of FIGS. 5-16 is repeated, and pressure | voltage reduction processing is performed. As described above, the basic operation of the present embodiment is such that current in the same direction (in the direction from the terminal Tc2 to the terminal Tc1 of the choke coil 7) flows through the choke coil 7 continuously during the step-down process. In addition, the gate of each transistor is controlled so that no high voltage is generated in the choke coil 7 so that the step-down voltage is controlled with high accuracy.
That is, at times t0 to t11 shown in the timing chart of FIG. 17, the operations of FIGS. 5 to 16 are performed, and a desired low voltage VoL is output to the battery B1.

Further, in the above-described embodiment, when the winding ratio set corresponding to the step-down operation is set, the boost voltage can be output as the set voltage value as the first voltage of the first voltage. The battery (battery B2) has been described as a high voltage, and the second voltage battery (battery B1) as a low voltage lower than the first voltage.
However, when the winding ratio set corresponding to the boost operation is set, the first voltage of the battery B2 is set to a low voltage as a configuration capable of outputting the step-down voltage as the set voltage value. The second voltage of the battery B1 may be configured as a high voltage.
In this case, a voltage value of a low voltage that does not reach the set voltage is boosted by the booster circuit 4 and output as a low voltage of the set voltage value.

Next, as another embodiment of the present invention, FIG. 18 shows a DC / DC converter in which the transistors in the primary side orthogonal transform unit 2 and the secondary side orthogonal transform unit 3 have a three-phase bridge configuration.
In this figure, the bidirectional DC / DC converter according to the present embodiment replaces the transformer 1 of the above-described embodiment, and includes transformers 11, 12, and 13, a primary side orthogonal transform unit 2, and a secondary side orthogonal transform unit. 3. A booster circuit 4 is provided.
With the above-described configuration, the bidirectional DC / DC converter according to the other embodiment is similar to the above-described embodiment in that the secondary side orthogonal transform unit 3 is connected to the battery B1 in the voltage conversion (energy conversion) of the boosting process. The DC low voltage VoH at 1 is converted into a three-phase rectangular wave AC voltage at one end, and the primary side orthogonal transformation unit 2 rectifies the three-phase rectangular wave AC voltage and converts it into a DC high voltage VoH (battery B2). To do.
On the other hand, in the bidirectional DC / DC converter , in the energy conversion of the step-down process, the primary side orthogonal transform unit 3 converts the DC high voltage VoH in the battery B2 into a three-phase rectangular wave AC voltage at one end. The side orthogonal conversion unit 3 rectifies the three-phase rectangular wave AC voltage and converts it into a DC low voltage VoL (battery B1).

In FIG. 6, the primary-side orthogonal transform unit 2 includes N-channel MOS transistors (hereinafter simply referred to as transistors) Q1, Q2, Q3, Q4, Q11, and Q12, and a first control circuit 5, and is configured as an inverter. It has become.
The drains of the transistors Q1, Q3, and Q11 are connected to the + side terminal TVoL of the low voltage battery B1.
On the other hand, the sources of the transistors Q2, Q4 and Q12 are connected to the negative terminal TVoLL of the low voltage battery B1.
The source of transistor Q1 is connected to the drain of transistor Q2 at connection point K1, the source of transistor Q3 is connected to the drain of transistor Q4 at connection point K2, and the source of transistor Q11 is connected to the drain of transistor Q12 and connection point K3. Connected.

One terminal of the primary winding 13A in the transformer 13 and the other terminal of the primary winding 12A in the transformer 12 are connected to the connection point K1, and one terminal of the primary winding 12A in the transformer 12 and 1 in the transformer 11 are connected. The other terminal of the secondary winding 11A is connected to the connection point K2, and one terminal of the primary winding 11A in the transformer 11 and the other terminal of the primary winding 13A in the transformer 13 are connected to the connection point K3. .
In addition, the transistors Q1, Q2, Q3, Q4, Q11, and Q12 receive the control signals S1, S2, S3, S4, S11, and S12 from the first control circuit 5 to the respective gates. Yes.
The first control circuit 5 outputs each control signal at “H” level or “L” level, and outputs the primary winding 11A of the transformer 11, the primary winding 12A of the transformer 12, and the primary of the transformer 13. The direction of the current flowing through each of the windings 13A is controlled to be in reverse phase at a constant period. As a result, a single-phase rectangular wave AC voltage is applied to each of the primary winding 11A of the transformer 11, the primary winding 12A of the transformer 12, and the primary winding 13A of the transformer 13.

The secondary side orthogonal transform unit 4 includes N channel type MOS transistors (hereinafter simply referred to as transistors) Q7, Q8, Q9, Q10, Q13, Q14 and a second control circuit 6.
The transistor Q7 has a drain connected to the terminal Tc1 of the choke coil 7 and a source connected to the connection point P1.
The transistor Q9 has a drain connected to the terminal Tc1 of the choke coil 7 and a source connected to the connection point P2.
The transistor Q13 has a drain connected to the terminal Tc1 of the choke coil 7 and a source connected to the connection point P3.
The transistor Q8 has a drain connected to the connection point P1, and a source connected to the negative terminal TvoLL of the low voltage battery B2.
The transistor Q10 has a drain connected to the connection point P2, and a source connected to the negative terminal TvoLL of the low voltage battery B2.
The transistor Q14 has a drain connected to the connection point P3 and a source connected to the negative terminal TvoLL of the low voltage battery B2.

The connection point P1 is connected to one terminal of the secondary winding 11B in the transformer 11 and the other terminal of the secondary winding 13B in the transformer 13, and the connection point P2 is connected to the other terminal of the secondary winding 11B in the transformer 11 and It is connected to one terminal of the secondary winding 12B in the transformer 12, and the connection point P3 is connected to the other secondary winding 12B in the transformer 12 and one secondary winding 13B in the transformer 13.
The transistors Q7, Q8, Q9, Q10, Q13, and Q14 are supplied with control signals S7, S8, S9, S10, S13, and S14, respectively, from the second control circuit 6 to the respective gates. Yes.
The second control circuit 6 outputs each control signal at the “H” level or “L” level, and outputs the secondary winding 11B of the transformer 11, the secondary winding 12 of the transformer 12, and the secondary of the transformer 13. The direction of the current flowing through each of the windings 13B is controlled to be in reverse phase at a constant period. As a result, the single-phase rectangular wave AC voltage is applied to the secondary winding 11B of the transformer 11, the secondary winding 12 of the transformer 12, and the secondary winding 13B of the transformer 13.
Since the booster circuit 4 is the same as that of the above-described embodiment, the description thereof is omitted.

As described above, in the primary side orthogonal transform unit 2, the structure of the composite switch including the transistors Q1 to Q4, Q11, and Q12 has an inverter configuration that generates a three-phase rectangular wave AC voltage.
In the step-up operation, corresponding to the three-phase rectangular wave AC voltage, the secondary side orthogonal transformation unit 3 includes a primary winding 11A of the transformer 11, a primary winding 12A of the transformer 12, and a primary winding 13A of the transformer 13. Due to the current flowing through each of them, the voltage induced in the reverse phase in each of the secondary winding 11B of the transformer 11, the secondary winding 12 of the transformer 12, and the secondary winding 13B of the transformer 13 is high by performing three-phase bridge rectification. The voltage VoH is generated.
The secondary side orthogonal transform unit 3 includes the secondary winding 11B of the transformer 11, the secondary winding 12 of the transformer 12, and the transformer by bridge rectification by the parasitic diodes D7, D9, and D13 of the transistors Q7, Q9, and Q13. The rectifying operation of the single-phase rectangular wave AC voltage induced in each of the 13 secondary windings 13B is performed.
Here, in the step-up operation, the second control circuit 6 does not perform the two-wave rectification using the diode as described above, but synchronizes with the above-described switching of the transistors Q1 to Q4, Q11, and Q12. ~ Single-phase rectangular wave AC induced in each of the secondary winding 11B of the transformer 11, the secondary winding 12 of the transformer 12, and the secondary winding 13B of the transformer 13 by synchronous rectification that turns on and off Q10, Q13, and Q14 A voltage rectification operation may be performed.

In the boosting operation described above, the first control circuit 5 controls the transistor Q1 corresponding to the connection point K1 with respect to the phase of the control signals S3 and S4 applied to the gates of the transistors Q3 and Q4 corresponding to the connection point K2. And the phase of the control signals S1 and S2 applied to the gates of Q2 and the phase of the control signals S11 and S12 applied to the gates of the transistors Q11 and Q12 corresponding to the connection point K3 are lowered. Control the voltage value. Here, the periods when the control signals S3 and S4, the control signals S1 and S2, and the control voltages S11 and S12 are at the “H” level and the “L” level have the same length.
Also, instead of the phase control described above, the pulse widths of the control signals S1, S2, S3, S4, S11, and S12 are adjusted, and the on / off times of the transistors Q1 to Q4, Q11, and Q12 are controlled to control the boost voltage. You may use PWM control which controls a voltage value.

On the other hand, in the secondary side orthogonal transform unit 3, the structure of the composite switch including the transistors Q7 to Q10, Q13, and Q14 is an inverter configuration that generates one three-phase rectangular wave AC voltage.
In the step-down operation, corresponding to the three-phase rectangular wave AC voltage, the primary side orthogonal transform unit 2 includes a secondary winding 11B of the transformer 11, a secondary winding 12 of the transformer 12, and a secondary winding 13B of the transformer 13. Due to the current flowing through each of them, the voltage induced in the negative phase in each of the primary winding 11A of the transformer 11, the primary winding 12A of the transformer 12, and the primary winding 13A of the transformer 13 is reduced by three-phase bridge rectification. The voltage VoH is generated.

The primary side orthogonal transform unit 2 includes a primary winding 11A of the transformer 11, a primary winding 12A of the transformer 12, and a transformer by bridge rectification using the parasitic diodes D1, D3, and D11 of the transistors Q1, Q3, and Q11. The rectifying operation of the single-phase rectangular wave AC voltage induced in each of the 13 primary windings 13A is performed.
Here, in the step-up operation, the first control circuit 5 does not perform the bridge rectification using the diode as described above, but synchronizes with the switching described above of the transistors Q7 to Q10, Q13, and Q14. Single-phase rectangular wave AC voltage induced in each of the primary winding 11A of the transformer 11, the primary winding 12A of the transformer 12, and the primary winding 13A of the transformer 13 by synchronous rectification that turns on and off Q4, Q11, and Q12 The rectifying operation may be performed.

In the step-down operation described above, the second control circuit 6 changes the duty between the “H” level and the “L” level of the control signal S5 for turning on / off the transistor Q5 in the same manner as in the already described embodiment, and performs choke. The voltage value of the step-down voltage is controlled by adjusting the electric energy supplied to the coil 7.
The step-up and step-down operations are omitted because the switching of each transistor is the same as in the embodiment.

It is a figure which shows the structural example of the bidirectional | two-way DC / DC converter by one Embodiment of this invention. It is a figure which shows the structural example of the bidirectional | two-way DC / DC converter for demonstrating step-down operation. It is a wave form diagram explaining the pressure | voltage rise operation of the bidirectional | two-way DC / DC converter of FIG. It is a figure which shows the structural example of the bidirectional | two-way DC / DC converter for demonstrating step-down operation. FIG. 5 is a conceptual diagram illustrating switching control of transistors Q5 to Q10 in the step-down operation of the bidirectional DC / DC converter of FIG. FIG. 5 is a conceptual diagram illustrating switching control of transistors Q5 to Q10 in the step-down operation of the bidirectional DC / DC converter of FIG. FIG. 5 is a conceptual diagram illustrating switching control of transistors Q5 to Q10 in the step-down operation of the bidirectional DC / DC converter of FIG. FIG. 5 is a conceptual diagram illustrating switching control of transistors Q5 to Q10 in the step-down operation of the bidirectional DC / DC converter of FIG. FIG. 5 is a conceptual diagram illustrating switching control of transistors Q5 to Q10 in the step-down operation of the bidirectional DC / DC converter of FIG. FIG. 5 is a conceptual diagram illustrating switching control of transistors Q5 to Q10 in the step-down operation of the bidirectional DC / DC converter of FIG. FIG. 5 is a conceptual diagram illustrating switching control of transistors Q5 to Q10 in the step-down operation of the bidirectional DC / DC converter of FIG. FIG. 5 is a conceptual diagram illustrating switching control of transistors Q5 to Q10 in the step-down operation of the bidirectional DC / DC converter of FIG. FIG. 5 is a conceptual diagram illustrating switching control of transistors Q5 to Q10 in the step-down operation of the bidirectional DC / DC converter of FIG. FIG. 5 is a conceptual diagram illustrating switching control of transistors Q5 to Q10 in the step-down operation of the bidirectional DC / DC converter of FIG. FIG. 5 is a conceptual diagram illustrating switching control of transistors Q5 to Q10 in the step-down operation of the bidirectional DC / DC converter of FIG. FIG. 5 is a conceptual diagram illustrating switching control of transistors Q5 to Q10 in the step-down operation of the bidirectional DC / DC converter of FIG. FIG. 5 is a waveform diagram for explaining a step-down operation of the bidirectional DC / DC converter of FIG. 4. It is a figure which shows the structural example of the bidirectional | two-way DC / DC converter of the three-phase structure which is other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Transformer 1A ... Primary winding 1B ... Secondary winding 2 ... Primary side orthogonal transformation part 3 ... Secondary side orthogonal transformation part 4 ... Booster circuit 5 ... 1st control circuit 6 ... 2nd control circuit 7 ... choke coils 8, 9 ... capacitors B1, B2 ... batteries D1, D2, D3, D4, D5, D6, D7, D8, D9, D10 ... diodes Q1, Q2, Q3, Q4, Q5, Q6, Q7, Q8, Q9, Q10 ... Transistor

Claims (7)

A bidirectional DC / DC converter that performs a voltage conversion operation between the first voltage and a second voltage having a voltage value lower than the first voltage;
A transformer comprising a primary winding and a secondary winding having more turns than the primary winding;
First switch means interposed between one end of the primary winding and the + side terminal of the second voltage;
Second switch means interposed between the one end of the primary winding and the negative terminal of the second voltage;
A third switch means interposed between the other end of the primary winding and the + side terminal of the second voltage;
A fourth switch means interposed between the other end of the primary winding and a negative terminal of the second voltage;
A choke coil provided between one end of the secondary winding and the positive terminal of the first voltage;
Fifth switch means interposed between one end of the choke coil and the positive terminal of the first voltage;
A sixth switch means interposed between the one end of the choke coil and a negative terminal of the first voltage;
A seventh switch means interposed between one end of the secondary winding and the other end of the choke coil;
An eighth switch means interposed between the one end of the secondary winding and the negative terminal of the first voltage;
Ninth switch means interposed between the other end of the secondary winding and the other end of the choke coil;
A tenth switch means interposed between the other end of the secondary winding and a negative terminal of the first voltage;
When converting the second voltage to the first voltage, if the boost voltage does not reach the set voltage only by the turn ratio between the first winding and the second winding, the choke coil A voltage that is used for boosting the boosted voltage, and on the other hand, when the second voltage is converted to the first voltage, the step-down voltage is set only by the turn ratio between the first winding and the second winding. If not reached, after antihypertensive treatment of the first voltage by the choke coil, have rows buck to the step-down voltage by the transformer,
A second control circuit for controlling the seventh to tenth switch means;
A second rectifier circuit connected to the primary winding comprising a diode connected in parallel to each of the first to fourth switch means;
Further comprising
In the step-down operation, when the first voltage is a high voltage and the second voltage is a low voltage,
The second control circuit periodically controls the seventh and ninth switch means to connect one end or the other end of the secondary winding to the other end of the choke coil. And controlling the eighth and tenth switch means periodically to connect one end or the other end of the secondary winding to the negative terminal of the first voltage. The push-pull operation is performed so that the direction of the current flowing through the primary winding is reversed every cycle.
A bidirectional DC / DC converter characterized in that the rectified voltage output from the second rectifier circuit is smoothed and output as a step-down voltage . A first control circuit for controlling the first to fourth switch means;
A first rectifier circuit connected to the secondary winding consisting of a diode connected in parallel to each of the seventh to tenth switch means;
In the step-up operation from the second voltage to the first voltage,
The first control circuit periodically controls the first and third switch means, and either one end or the other end of the primary winding, and a positive side terminal of the second voltage, And controlling the second and fourth switch means periodically to connect one end or the other end of the primary winding and the negative terminal of the second voltage. Connected, and push-pull operation so that the direction of the current flowing in the secondary winding is reversed every cycle,
At this time, if the step-down voltage does not reach the preset voltage,
The first rectified voltage output from the first rectifier circuit is boosted by performing the step-up operation of the first rectified voltage in the choke coil by controlling the sixth switch means on and off. The bidirectional DC / DC converter according to claim 1, wherein the voltage is output as a boosted voltage. In step-up operation,
The first control circuit controls the on / off timing of each of the first and third switch means and the second and fourth switch means by one or both of phase and pulse width control, and The bidirectional DC / DC converter according to claim 2, wherein the boosted voltage is controlled to be a preset voltage. In the step-down operation, the seventh, eighth, ninth and tenth switching means are controlled so that a current is continuously supplied to the choke coil in the same direction during the step-down operation. bidirectional DC / DC converter according to any one of 3. In step-down operation,
It said second control circuit, by controlling the duty ratio of a pulse for turning on and off the fifth switch means of claims 1, wherein the reduced voltage is controlled to be preset voltage The bidirectional DC / DC converter according to claim 3 . The first to fourth and seventh to tenth switch means are MOS transistors, and the diodes connected in parallel are the parasitic diodes of the MOS transistors to constitute the first and second rectifier circuits. bidirectional DC / DC converter as claimed in any one of claims 5, characterized in. A bidirectional DC / DC converter that performs a voltage conversion operation between a first voltage and a second voltage having a voltage value lower than the first voltage;
A first transformer comprising a first primary winding and a first secondary winding having a larger number of turns than the first primary winding;
A second transformer comprising a second primary winding and a second secondary winding having a larger number of turns than the second primary winding;
A third transformer comprising a third primary winding and a third secondary winding having a larger number of turns than the third primary winding;
First switch means interposed between the other end of the second primary winding and one end of the third primary winding, and a positive terminal of the second voltage;
Second switch means interposed between the other end of the second primary winding and one end of the third primary winding, and a negative terminal of the second voltage;
Third switch means interposed between the other end of the first primary winding and one end of the second primary winding, and a positive terminal of the second voltage;
A fourth switch means interposed between the other end of the first primary winding and one end of the second primary winding, and a negative terminal of the second voltage;
Eleventh switching means interposed between the other end of the third primary winding and one end of the first primary winding, and the positive terminal of the second voltage;
A twelfth switch means interposed between the other end of the third primary winding and one end of the first primary winding and a negative terminal of the second voltage;
A choke coil provided between one end of each secondary winding and the positive terminal of the first voltage;
Fifth switch means interposed between one end of the choke coil and the positive terminal of the first voltage;
A sixth switch means interposed between the one end of the choke coil and a negative terminal of the first voltage;
Seventh switch means interposed between one end of the first secondary winding and the other end of the third primary winding and the other end of the choke coil;
An eighth switch means interposed between one end of the first secondary winding and the other end of the third primary winding, and a negative terminal of the first voltage;
Ninth switch means interposed between the other end of the first secondary winding and one end of the second secondary winding and the other end of the choke coil;
A tenth switch means interposed between the other end of the first secondary winding and one end of the second secondary winding and the negative terminal of the first voltage;
A thirteenth switch means interposed between the other end of the second secondary winding and one end of the third secondary winding and the other end of the choke coil;
Fourteenth switch means interposed between the other end of the second secondary winding and one end of the third secondary winding, and a negative terminal of the first voltage;
Have
When converting the second voltage to the first voltage, if the boost voltage does not reach the set voltage only by the turn ratio between the first winding and the second winding, the choke coil A voltage that is used for boosting the boosted voltage, and on the other hand, when the second voltage is converted to the first voltage, the step-down voltage is set only by the turn ratio between the first winding and the second winding. If not reached, after antihypertensive treatment of the first voltage by the choke coil, have rows buck to the step-down voltage by the transformer,
A second control circuit for controlling the seventh to tenth, thirteenth and fourteenth switch means;
A second rectifier circuit connected to the primary winding comprising a diode connected in parallel to each of the first to fourth and eleventh and twelfth switch means;
Further comprising
In the step-down operation, when the first voltage is a high voltage and the second voltage is a low voltage,
The second control circuit periodically controls the seventh, ninth, and thirteenth switch means, and either one end or the other end of the secondary winding and the other of the choke coil Control the connection to the end, and periodically control the eighth, tenth, and fourteenth switch means, and either the one end or the other end of the secondary winding and the first voltage And a push-pull operation so that the direction of the current flowing through the primary winding is reversed every cycle, and the rectified voltage output from the second rectifier circuit is smoothed. A bidirectional DC / DC converter characterized by being output as a step-down voltage .

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