JP2011041340A - Dc-dc converter circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a DC-DC converter circuit enabling quick mode switching, and further reduction in conduction loss by semiconductor elements than conventional circuit, thereby improving power conversion efficiency. <P>SOLUTION: The DC-DC converter circuit 10 includes semiconductor switches S1, S2 and S4-S6; a diode D3 and an inductor L wherein all of the semiconductor switches S1, S2 and the diode D3 are connected to one end of the inductor L; all of the semiconductor switches S4-S6 are connected to the other end of the inductor L; a first voltage source E1 is connected to ends at the opposite sides of the connecting ends at which the semiconductor switches S1, S4 are connected to the inductor L; a second voltage source E2 is connected to ends at the opposite sides of the connecting ends at which the semiconductor switches S2, S5 are connected to the inductor L; and both the first voltage source E1 and the second voltage source E2 are connected to ends at the opposite sides of the connecting ends at which the diode D3 and the semiconductor switch S6 are connected to the inductor L. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a DC-DC converter circuit, and more particularly to reduction of conduction loss in a bidirectional buck-boost DC-DC converter circuit.

  The DC-DC converter circuit is connected between, for example, a first DC voltage source and a second DC voltage source (hereinafter simply referred to as a first voltage source and a second voltage source), and based on output voltages of the first voltage source and the second voltage source, It is used as a bidirectional switching circuit capable of supplying power from one voltage source to the second voltage source or supplying power from the second voltage source to the first voltage source.

  For example, the DC-DC converter circuit may be used for an electric vehicle such as a work vehicle. In general, an electric vehicle operates a vehicle driving motor such as a motor with AC power obtained by converting DC power from a power storage device such as a battery or a capacitor into AC power using a power conversion circuit such as an inverter circuit. It is like that. The DC-DC converter circuit is provided between the power storage device acting as the first voltage source and the second voltage source to which a power conversion circuit such as an inverter circuit is connected, and converts power from the power storage device in the powering mode. While power is supplied to the circuit, power can be supplied from the power conversion circuit to the power storage device in the regeneration mode.

  As a conventional DC-DC converter circuit, for example, there is a chopper circuit described in Patent Document 1 (see FIG. 1 of Patent Document 1).

  FIG. 10 is a circuit diagram showing an example of a conventional DC-DC converter circuit. The DC-DC converter circuit shown in FIG. 10 includes first to fourth semiconductor switches 121 to 124, first to fourth diodes 125 to 128, and an inductor 129.

  Each of the first to fourth semiconductor switches 121 to 124 is a semiconductor device that can flow a current only in one direction. The first and second diodes 125 and 126 are respectively connected in parallel with the first semiconductor switch 121 and the second semiconductor switch 121 and 122 being connected in parallel, with the direction in which current can flow reversed. The cathode side of the first diode 125 connected in parallel and the anode side of the second diode 126 connected in parallel to the second semiconductor switch 122 are connected.

  The current inflow side of the third semiconductor switch 123 and the cathode side of the first diode 125 connected in parallel to the first semiconductor switch 121 are connected, and the cathode side of the fourth diode 128 and the second semiconductor switch 122 are connected in parallel. The second diode 126 is connected to the anode side.

  The inductor 129 has one end connected to both the current outflow side of the third semiconductor switch 123 and the cathode side of the third diode 127, and the other end connected to the anode side of the fourth diode 128 and the current inflow of the fourth semiconductor switch 124. Is connected to both sides.

  In the DC-DC converter circuit shown in FIG. 10, the first voltage source 110 is connected between the anode side of the first diode 125 and the anode side of the third diode 127 connected in parallel to the first semiconductor switch 121. The second voltage source 120 is connected between the cathode side of the second diode 126 connected in parallel to the second semiconductor switch 122 and the current outflow side of the fourth semiconductor switch 124.

  In such a conventional DC-DC converter circuit, the following power running mode and regenerative mode can be exemplified as the operation modes indicating the on and off states of the semiconductor switches 121 to 124.

  FIG. 11 is a diagram illustrating a state where the DC-DC converter circuit illustrated in FIG. 10 is operating in the power running mode.

  For example, as shown in FIG. 11, the power running mode is a current path Ra that returns from the first voltage source 110 to the first voltage source 110 through the first diode 125, the third semiconductor switch 123, the inductor 129, and the fourth semiconductor switch 124. It is set as the mode which forms.

  FIG. 12 is a diagram illustrating a state in which the DC-DC converter circuit illustrated in FIG. 10 is operating in the regeneration mode.

  In the regeneration mode, for example, as shown in FIG. 12, a current path Rb from the first voltage source 110 to the first voltage source 110 via the third diode 127, the inductor 129, the fourth diode 128, and the first semiconductor switch 121 is obtained. It is a mode to form.

  In such a conventional DC-DC converter circuit, in the current path Ra in the power running mode and the current path Rb in the regenerative mode, the direction of the current flowing through the inductor 129 is made constant. In this way, when the mode switching between the power running mode and the regenerative mode is performed by switching the operation of each of the semiconductor switches 121 to 124 between the on state and the off state, the current flowing through the inductor 129 is not reversed. The time required for mode switching can be reduced, and a quick mode switching process can be performed. However, when the output voltage V1 of the first voltage source 110 is higher than the output voltage V2 of the second voltage source 120, the first and second diodes 125 and 126 are turned on, and the output voltage V1 and the output voltage V2 Therefore, the output voltage V2 of the second voltage source 120 cannot be reduced below the output voltage V1 of the first voltage source 110.

JP 2007-151111 A

  By the way, in a DC-DC converter circuit, if the number of semiconductor elements through which current passes increases, the conduction loss increases accordingly, and the power conversion efficiency decreases accordingly.

  In the conventional DC-DC converter circuit shown in FIG. 10, as a semiconductor element, for example, a current passes through the first diode 125, the third semiconductor switch 123, and the fourth semiconductor switch 124 in a powering mode (see FIG. 11). Become. Further, current passes through the third diode 127, the fourth diode 128, and the first semiconductor switch 121 in the regeneration mode (see FIG. 12). That is, in both the power running mode and the regenerative mode, since current passes through at least three semiconductor elements, the conduction loss increases accordingly, and the power conversion efficiency decreases accordingly.

  Therefore, the present invention can perform a mode switching process between the power running mode and the regenerative mode more quickly, and can reduce the conduction loss of the semiconductor element as compared with the conventional DC-, thereby improving the power conversion efficiency. An object is to provide a DC converter circuit.

  In order to solve the above problems, the present invention provides first, second, fourth, fifth and sixth semiconductor switches each capable of flowing a current in one direction, a third diode, an inductor, The first and second semiconductor switches and the third diode are both connected in a direction in which a current flows into one end of the inductor, and the fourth to sixth Each of the semiconductor switches is connected to the other end of the inductor in a direction in which current flows out, and the first voltage source is connected to the end of the first and fourth semiconductor switches opposite to the connection end of the inductor. The anode side of the second voltage source is connected to the opposite end of the second and fifth semiconductor switches to the connection end of the inductor, and the third diode and the sixth semiconductor switch The in The connecting end of Kuta to provide a DC-DC converter circuit, characterized in that both the cathode side of the cathode side of the first voltage source to the opposite end the second voltage source is connected.

  According to the DC-DC converter circuit of the present invention, the output voltage can be stepped up and down in both directions between the first voltage source and the second voltage source. In addition, power can be supplied bidirectionally between the first voltage source and the second voltage source. Furthermore, the direction of the current flowing through the inductor can be made constant. In this way, when switching between the power running mode and the regenerative mode by switching the operation of each semiconductor switch between the on state and the off state, the current flowing through the inductor is not reversed. Time required for switching can be reduced, and quick mode switching processing can be performed. In addition, current can be passed through at least two semiconductor elements (semiconductor elements that are two-thirds of the conventional semiconductor elements), and the conduction loss can be reduced accordingly, thereby improving the power conversion efficiency. This effect will be described in detail in the following embodiment.

  By the way, as a module used in a power conversion circuit such as an inverter circuit, a module (so-called 2-in-1 module) in which two reverse conducting semiconductor elements are connected in series and formed integrally is commercially available. In the DC-DC converter circuit according to the present invention, it may be preferable to use this 2-in-1 module depending on design specifications such as power capacity.

  From such a viewpoint, in the DC-DC converter circuit according to the present invention, the first, second, fourth, fifth and sixth semiconductor switches can be configured as a circuit to which a 2-in-1 module can be applied. The first, second, and second semiconductor switches connected in parallel to the first, second, fourth, fifth, and sixth semiconductor switches so that the current can flow in a direction opposite to the direction in which the current can be turned on and off, respectively. , Fourth, fifth and sixth diodes, and between the first, second, fourth, fifth and sixth semiconductor switches and the inductor, respectively. An embodiment may further include a seventh, eighth, tenth, eleventh and twelfth diodes connected so as to allow a current to flow in the opposite direction to the fifth and sixth diodes. .

  Examples of the semiconductor switch include semiconductor switches such as IGBT (Insulated Gate Bipolar Transistor), MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor), and GTO (Gate Turn-Off thyristor). As the reverse conducting semiconductor element, a semiconductor element such as a semiconductor element or a MOSFET in which diodes are connected in parallel with the direction in which a current can flow can be reversed with respect to a semiconductor switch such as IGBT, GTO, etc. A semiconductor element in which a diode (or body diode) is present can be exemplified, and examples thereof include a reverse conduction type IGBT element, a reverse conduction type MOSFET element, and a reverse conduction type GTO element.

  A gate drive power supply may be used for each semiconductor switch. However, depending on the design specifications such as power capacity, the number of gate drive power supplies can be reduced by using a common gate drive power supply for the semiconductor switches. It may be preferable to do so.

  From this point of view, in the DC-DC converter circuit according to the present invention, as an aspect capable of configuring a circuit capable of reducing the number of gate drive power supplies, the first and second semiconductor switches each turn on current. , First and second diodes connected in parallel to the first and second semiconductor switches so as to allow a current to flow in a direction opposite to the direction in which the off control can be performed, the first semiconductor switch, and the first voltage A fourth diode connected to the anode side of the source so as to allow a current to flow in a direction opposite to that of the first diode; the second semiconductor switch; and an anode of the second voltage source An embodiment may further include a fifth diode connected between the first diode and the second diode so that a current can flow in a direction opposite to that of the second diode.

Further, from the viewpoint of preventing the breakdown of the first to sixth semiconductor switches due to the high voltage, in the DC-DC converter circuit according to the present invention, the following aspects (a) to (c) are adopted. Is preferred. That is,
As an aspect of (a), in the case where a current flows through the inductor, an aspect including means for always turning on one or more semiconductor switches among the fourth to sixth semiconductor switches. It can be illustrated.

  As an aspect of (b), when a current flows through the inductor, the first to second semiconductor switches among the fourth to sixth semiconductor switches are turned off before the fourth to sixth semiconductor switches are turned off. A mode provided with the means for turning on at least one of semiconductor switches other than the semiconductor switch made into an OFF state among the 6th semiconductor switches to an ON state beforehand can be illustrated.

  As an aspect of (c), when an operation mode indicating the on state and the off state of the first, second, fourth, fifth, and sixth semiconductor switches is changed in a state where a current flows through the inductor. Means for turning on all semiconductor switches that are on in the operation mode before the change for a certain period of time after the change of operation mode, or all semiconductor switches that are on in the operation mode after the change A mode provided with means for turning on the device for a certain period of time before changing the operation mode can be exemplified.

  As described above, according to the present invention, the mode switching process between the power running mode and the regenerative mode can be performed quickly, and the conduction loss of the semiconductor element can be reduced as compared with the conventional one, thereby improving the power conversion efficiency. The DC-DC converter circuit which can be provided can be provided.

It is a circuit diagram showing a DC-DC converter circuit concerning an embodiment of the invention. FIG. 2 is a diagram illustrating a state in which the DC-DC converter illustrated in FIG. 1 is operating in a powering mode, in which FIG. (A) illustrates a first mode, and (b) illustrates a second mode. FIG. 8C is a diagram illustrating the third mode. FIG. 2 is a diagram illustrating a state in which the DC-DC converter illustrated in FIG. 1 is operating in a regenerative mode, in which FIG. (A) illustrates a fourth mode, and (b) illustrates a fifth mode. FIG. 8C is a diagram showing the sixth mode. FIG. 2 is a diagram illustrating a state in which the DC-DC converter circuit illustrated in FIG. 1 operates in a reflux mode, in which FIG. (A) illustrates a seventh mode, and FIG. (B) illustrates an eighth mode. FIG. 10C is a diagram illustrating the ninth mode. It is a figure which shows the example of the 2 in 1 module which can be used for a 1st, 2nd, 4th and 5th semiconductor switch. It is a circuit diagram of the 1st example which can constitute a circuit which can apply 2in1 module. FIG. 6 is a circuit diagram of a second embodiment capable of configuring a circuit that can reduce the number of gate drive power supplies. FIG. 9 is a state transition diagram showing an example of a case where the operation mode is changed from one mode to another mode among the first to ninth modes in the third control example, and FIG. FIG. 5B is a diagram showing a commutation state from the first mode to the second mode, which is an example in the case where there are one current path in the commutation state, and FIG. These are figures which show the state of 2nd mode. FIG. 9 is a state transition diagram showing an example of a case where the operation mode is changed from one mode to another mode among the first to ninth modes in the third control example, and FIG. FIG. 4B shows a case where there are two current paths in the commutation state, and the current paths differ depending on the magnitude relationship between the output voltage of the first voltage source and the output voltage of the second voltage source. It is a figure which shows the commutation state from the 1st mode which is an example to the 5th mode, and a figure (c) is a figure which shows the state of a 5th mode. It is a circuit diagram which shows an example of the conventional DC-DC converter circuit. It is a figure which shows the state which is operate | moving in power running mode in the DC-DC converter circuit shown in FIG. It is a figure which shows the state which is operate | moving in regeneration mode in the DC-DC converter circuit shown in FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. The following embodiments are examples embodying the present invention, and are not of a nature that limits the technical scope of the present invention.

  FIG. 1 is a circuit diagram showing a DC-DC converter circuit 10 according to an embodiment of the present invention.

  A DC-DC converter circuit 10 shown in FIG. 1 includes first, second, fourth, fifth, and sixth semiconductor switches S1, S2, S4, S5, and S6, a third diode D3, and an inductor L. ing.

  Each of the first, second, fourth, fifth and sixth semiconductor switches S1, S2, S4, S5 and S6 is a semiconductor device capable of flowing a current in one direction.

  The first and second semiconductor switches S1, S2 and the third diode D3 are all connected to one end of the inductor L (see connection point B) in a direction in which current flows.

  The fourth to sixth semiconductor switches S4 to S6 are all connected to the other end of the inductor L (see connection point C) in a direction in which current flows out.

  In the DC-DC converter circuit 10, the anode side of the first voltage source E1 is connected to the end opposite to the connection end of the inductor L of the first and fourth semiconductor switches S1 and S4 (see connection point A). The anode side of the second voltage source E2 is connected to the end opposite to the connection end of the inductor L of the second and fifth semiconductor switches S2, S5 (see connection point D).

  Further, the DC-DC converter circuit 10 has a second voltage that is connected to the cathode side of the first voltage source E1 (see connection point E) and the second voltage at the end opposite to the connection end of the third diode D3 and the inductor L of the sixth semiconductor switch S6. Both are connected to the cathode side (see connection point E) of the source E2.

  When the DC-DC converter circuit 10 is applied to a work vehicle, for example, the first and second voltage sources E1, E2 can be power storage devices such as a battery and a capacitor. The first and second voltage sources E1, E2 can be connected to a power conversion circuit such as an inverter circuit that operates a vehicle drive motor such as a motor.

  The DC-DC converter circuit 10 according to the present embodiment further includes a control device 20. The control device 20 includes a processing unit 21 such as a CPU (Central Processing Unit) and a storage unit 22. The storage unit 22 includes a storage memory such as a ROM (Read Only Memory) or a RAM (Random Access Memory), and stores various control programs, necessary functions and tables, and various data.

  The control device 20 is configured to control the switching operation of the first, second, fourth, fifth and sixth semiconductor switches S1, S2, S4, S5 and S6 of the DC-DC converter circuit 10.

  In the DC-DC converter circuit 10 according to the present embodiment, as the operation mode indicating the on state and the off state of the first, second, fourth, fifth, and sixth semiconductor switches S1, S2, S4, S5, and S6. Examples of the first mode to the third mode that operate in the power running mode and examples of the fourth mode to the sixth mode that operate in the regenerative mode can be given.

  FIG. 2 is a diagram illustrating a state in which the DC-DC converter circuit 10 illustrated in FIG. 1 is operating in the powering mode. FIG. 2 (a) shows the first mode, FIG. 2 (b) shows the second mode, and FIG. 2 (c) shows the third mode.

  FIG. 3 is a diagram showing a state where the DC-DC converter circuit 10 shown in FIG. 1 is operating in the regeneration mode. 3A shows the fourth mode, FIG. 3B shows the fifth mode, and FIG. 3C shows the sixth mode.

  In the power running mode, for example, in the first mode, as shown in FIG. 2A, the first and sixth semiconductor switches S1 and S6 are turned on, and the other second, fourth and fifth semiconductor switches. A mode in which S2, S4, and S5 are turned off to form a first current path R1 that returns from the first voltage source E1 to the first voltage source E1 through the first semiconductor switch S1, the inductor L, and the sixth semiconductor switch S6. It can be.

  In the second mode, as shown in FIG. 2B, the first and fifth semiconductor switches S1, S5 are turned on, and the other second, fourth, and sixth semiconductor switches S2, S4, S6 are turned off. A mode of forming a second current path R2 from the first voltage source E1 through the first semiconductor switch S1, the inductor L, the fifth semiconductor switch S5 and the second voltage source E2 to the first voltage source E1. can do.

  In the third mode, as shown in FIG. 2C, the fifth semiconductor switch S5 is turned on, and the other first, second, fourth, and sixth semiconductor switches S1, S2, S4, and S6 are turned off. The mode can be changed to a mode in which a third current path R3 returning from the second voltage source E2 to the second voltage source E2 through the third diode D3, the inductor L, and the fifth semiconductor switch S5 is formed.

  When the power running mode is executed, the first mode, the second mode, and the third mode are selected according to the magnitude relationship between the output voltage V1 of the first voltage source E1 and the output voltage V2 of the second voltage source E2. Various switching operations for switching at least two modes at a short cycle (for example, any cycle of about 10 kHz to 100 kHz) can be executed.

  Specifically, when the output voltage V1 of the first voltage source E1 is larger than the output voltage V2 of the second voltage source E2, for example, a switching operation for switching between the second mode and the third mode may be executed. If the output voltage V1 of the first voltage source E1 is smaller than the output voltage V2 of the second voltage source E2, for example, a switching operation for switching between the first mode and the second mode can be executed. When the output voltage V1 of the first voltage source E1 and the output voltage V2 of the second voltage source E2 are equal, for example, a switching operation for switching between the first mode and the third mode is executed, or the second mode Can only run. When the output voltage V1 of the first voltage source E1 and the output voltage V2 of the second voltage source E2 are substantially equal (when the absolute value of the difference between the voltage V1 and the voltage V2 is within a predetermined range), A switching operation for switching between the mode and the third mode may be executed, or only the second mode may be executed.

  In the regenerative mode, for example, in the fourth mode, as shown in FIG. 3A, the second and sixth semiconductor switches S2 and S6 are turned on, and the other first, fourth, and fifth modes. The semiconductor switches S1, S4, and S5 are turned off to form a fourth current path R4 that returns from the second voltage source E2 to the second voltage source E2 through the second semiconductor switch S2, the inductor L, and the sixth semiconductor switch S6. Mode.

  In the fifth mode, as shown in FIG. 3B, the second and fourth semiconductor switches S2 and S4 are turned on, and the other first, fifth and sixth semiconductor switches S1, S5 and S6 are turned off. A mode in which a fifth current path R5 is formed from the second voltage source E2 to the second voltage source E2 via the second semiconductor switch S2, the inductor L, the fourth semiconductor switch S4, and the first voltage source E1. can do.

  In the sixth mode, as shown in FIG. 3C, the fourth semiconductor switch S4 is turned on, and the other first, second, fifth and sixth semiconductor switches S1, S2, S5, S6 are turned off. A state can be established in which a sixth current path R6 is formed from the first voltage source E1 to the first voltage source E1 through the third diode D3, the inductor L, and the fourth semiconductor switch S4.

  When the regeneration mode is executed, the fourth mode, the fifth mode, and the sixth mode are selected according to the magnitude relationship between the output voltage V1 of the first voltage source E1 and the output voltage V2 of the second voltage source E2. Various switching operations for switching at least two modes at a short cycle (for example, any cycle of about 10 kHz to 100 kHz) can be executed.

  Specifically, when the output voltage V1 of the first voltage source E1 is larger than the output voltage V2 of the second voltage source E2, for example, a switching operation for switching between the fourth mode and the fifth mode may be executed. If the output voltage V1 of the first voltage source E1 is smaller than the output voltage V2 of the second voltage source E2, for example, a switching operation for switching between the fifth mode and the sixth mode can be executed. When the output voltage V1 of the first voltage source E1 and the output voltage V2 of the second voltage source E2 are equal, for example, a switching operation for switching between the fourth mode and the sixth mode is executed, or the fifth mode Can only run. Note that when the output voltage V1 of the first voltage source E1 and the output voltage V2 of the second voltage source E2 are substantially equal (when the absolute value of the difference between the voltage V1 and the voltage V2 is within a predetermined range), A switching operation for switching between the mode and the sixth mode may be executed, or only the fifth mode may be executed.

  In the DC-DC converter circuit 10 according to the present embodiment, as the operation mode indicating the on state and the off state of the first, second, fourth, fifth, and sixth semiconductor switches S1, S2, S4, S5, and S6. The seventh mode to the ninth mode may be executed in the following operation in the reflux mode.

  FIG. 4 is a diagram illustrating a state in which the DC-DC converter circuit 10 illustrated in FIG. 1 is operating in the reflux mode. FIG. 4 (a) shows the seventh mode, FIG. 4 (b) shows the eighth mode, and FIG. 4 (c) shows the ninth mode.

  In the recirculation mode, for example, in the seventh mode, as shown in FIG. 4A, the first and fourth semiconductor switches S1 and S4 are turned on, and the other second, fifth and sixth semiconductor switches. S2, S5, and S6 are turned off, and the mode can be set to form the seventh current path R7 that circulates through the inductor L, the fourth semiconductor switch S4, and the first semiconductor switch S1.

  In the eighth mode, as shown in FIG. 4B, the sixth semiconductor switch S6 is turned on, and the other first, second, fourth, and fifth semiconductor switches S1, S2, S4, and S5 are turned off. The state can be changed to a mode in which an eighth current path R8 that circulates through the inductor L, the sixth semiconductor switch S6, and the third diode D3 is formed.

  In the ninth mode, as shown in FIG. 4C, the second and fifth semiconductor switches S2 and S5 are turned on, and the other first, fourth and sixth semiconductor switches S1, S4 and S6 are turned off. It becomes a state and it can be set as the mode which forms 9th electric current path R9 which circulates through inductor L, 5th semiconductor switch S5, and 2nd semiconductor switch S2.

  The output voltage V1 of the first voltage source E1 and the output voltage V2 of the second voltage source E2 can be measured with a voltmeter not shown.

  As described above, in the DC-DC converter 10 according to the embodiment of the present invention, the output voltages V1 and V2 are stepped up and down bidirectionally between the first voltage source E1 and the second voltage source E2. Can do. In addition, power can be supplied bidirectionally between the first voltage source E1 and the second voltage source E2. Furthermore, the direction of the current flowing through the inductor L can be made constant. In this way, the current flowing through the inductor L can be reversed when switching between the power running mode and the regenerative mode by switching the operation of the semiconductor switches S1, S2, S4, S5, and S6 between the on state and the off state. Therefore, the time required for mode switching can be reduced correspondingly, and a quick mode switching process can be performed. In addition, since the direction of the current flowing through the inductor L can be made constant, the electromagnetic offset type inductor L can be used, and this makes it possible to achieve downsizing. Moreover, as the semiconductor switch, for example, the first and sixth semiconductor switches S1 and S6 in the first mode (see FIG. 2A), the first and fifth semiconductors in the second mode (see FIG. 2B), for example. It is only necessary for the currents to pass through the switches S1 and S5 through the third diode D3 and the fifth semiconductor switch S5 in the third mode (see FIG. 2C). In the fourth mode (see FIG. 3A), the second and sixth semiconductor switches S2 and S6 are used. In the fifth mode (see FIG. 3B), the second and fourth semiconductor switches S2 and S4 are used. In the sixth mode (see FIG. 3C), only the current needs to pass through the third diode D3 and the fourth semiconductor switch S4. That is, in any mode from the first mode to the sixth mode (in both the power running mode and the regenerative mode), a current is applied to at least two semiconductor elements (semiconductor elements that are half of the conventional ones). Therefore, the conduction loss can be reduced accordingly, and the power conversion efficiency can be improved.

  In particular, the shorter the switching period of each mode, the larger the switching loss of the first, second, fourth, fifth and sixth semiconductor switches S1, S2, S4, S5 and S6. It can be effective.

  As the semiconductor switches that can be used for the first, second, fourth, fifth, and sixth semiconductor switches S1, S2, S4, S5, and S6, for example, reverse blocking IGBTs, MOSFETs, and GTOs are used. Can do.

  The first, second, fourth, and fifth semiconductor switches S1, S2, S4, and S5 are, for example, 2in1 modules that are integrally formed by connecting two reverse conducting semiconductor elements in series. it can.

  FIG. 5 is a diagram illustrating an example of a 2-in-1 module that can be used for the first, second, fourth, and fifth semiconductor switches S1, S2, S4, and S5. In the example shown in FIG. 5, the 2 in 1 module M is configured by a reverse conducting IGBT element. However, the present invention is not limited to this. For example, the 2 in 1 module may be configured with a reverse conducting MOSFET element or a reverse conducting GTO element.

  In the DC-DC converter circuit 10, the following first embodiment can be exemplified as an embodiment capable of configuring a circuit to which a 2 in 1 module can be applied.

[First embodiment]
FIG. 6 is a circuit diagram of a first embodiment capable of configuring a circuit to which a 2 in 1 module can be applied. In addition, each connection point AD shown in FIG. 6 respond | corresponds to each connection point AD shown in FIG. The same applies to the circuit of FIG. 7 described later.

  In the first embodiment, as shown in FIG. 6, the DC-DC converter circuit 10 includes first, second, fourth to eighth, and tenth to twelfth diodes D1, D2, D4 to D8, D10 to D12. Is further provided.

  The first, second, fourth, fifth and sixth diodes D1, D2, D4, D5, D6 are connected to the first, second, fourth, fifth and sixth semiconductor switches S1, S2, S4, S5. The first, second, fourth, fifth, and sixth semiconductor switches S1, S2, S4, S5, and S6 are configured so that S6 can flow a current in a direction opposite to a direction in which the current can be turned on and off, respectively. Connected in parallel.

  The seventh diode D7 is connected between the first semiconductor switch S1 and the inductor L (see connection point B) so that a current can flow in the opposite direction to the first diode D1. The eighth diode D8 is connected between the second semiconductor switch S2 and the inductor L (see connection point B) so that a current can flow in the opposite direction to the second diode D2.

  In addition, the tenth diode D10 is connected between the fourth semiconductor switch S4 and the inductor L (see the connection point C) so that a current can flow in the opposite direction to the fourth diode D4. The eleventh diode D11 is connected between the fifth semiconductor switch S5 and the inductor L (see the connection point C) so that a current can flow in the opposite direction to the fifth diode D5. The twelfth diode D12 is connected between the sixth semiconductor switch S6 and the inductor L (see the connection point C) so that a current can flow in the opposite direction to the sixth diode D6.

  In the first embodiment, the semiconductor element composed of the fourth semiconductor switch S4 and the fourth diode D4 is the first reverse conducting semiconductor element H1 of the upper arm, and is composed of the first semiconductor switch S1 and the first diode D1. The semiconductor element can be the second reverse conducting semiconductor element H2 of the lower arm.

  As a result, in the DC-DC converter circuit 10, the 2-in-1 module M1 formed integrally by connecting the first reverse conducting semiconductor element H1 and the second reverse conducting semiconductor element H2 in series can be used.

  Also, the semiconductor element composed of the fifth semiconductor switch S5 and the fifth diode D5 is the third reverse conducting semiconductor element H3 of the upper arm, and the semiconductor element composed of the second semiconductor switch S2 and the second diode D2 is the lower arm. The fourth reverse conducting semiconductor element H4 can be obtained.

  Thereby, in the DC-DC converter circuit 10, the 2in1 module M2 formed integrally by connecting the third reverse conduction type semiconductor element H3 and the fourth reverse conduction type semiconductor element H4 in series can be used.

  In this way, since the 2-in-1 modules M1 and M2 can be used, it is possible to realize an easy-to-use circuit configuration.

  By the way, in the circuit configuration of the first embodiment, as shown in FIG. 6, neither the first diode D1 nor the second diode D2 has a configuration capable of taking a common anode. For example, when the first and second semiconductor switches S1 and S2 are IGBTs, the configuration is not such that a common emitter can be taken. Further, when the first and second semiconductor switches S1 and S2 are MOSFETs, they are not configured to have a common source. Further, when the first and second semiconductor switches S1 and S2 are GTOs, the configuration is not such that a common cathode can be taken.

  Therefore, a gate drive power supply (not shown) provided for each of the first and second semiconductor switches S1 and S2, that is, a total of two gate drive power supplies is required.

  From this point of view, the following second example can be exemplified as an example capable of configuring a circuit capable of reducing the number of gate drive power supplies in the DC-DC converter circuit 10 according to the embodiment of the present invention.

[Second Embodiment]
FIG. 7 is a circuit diagram of a second embodiment capable of configuring a circuit capable of reducing the number of gate drive power supplies. FIG. 7 shows a portion of the inductor L on the connection point B side in the DC-DC converter circuit 10.

  In the second embodiment, as shown in FIG. 7, the DC-DC converter circuit 10 further includes first, second, fourth, and fifth diodes D1, D2, D4, and D5.

  The first and second diodes D1 and D2 include first and second semiconductors so that the first and second semiconductor switches S1 and S2 can pass current in a direction opposite to a direction in which current can be controlled on and off, respectively. The switches S1 and S2 are connected in parallel.

  The fourth diode D4 is connected between the first semiconductor switch S1 and the anode side of the first voltage source E1 (see connection point A) so that a current can flow in the opposite direction to the first diode D1. ing.

  The fifth diode D5 is connected between the second semiconductor switch S2 and the anode side of the second voltage source E2 (see the connection point D) so that a current can flow in the opposite direction to the second diode D2. ing.

  In the second embodiment, the anode side of the first diode D1 and the anode side of the second diode D2 are connected, and can be a common anode for the first diode D1 and the second diode D2 (dashed line). Part α).

  Thereby, in the DC-DC converter circuit 10, it can be set as the same (common) gate drive power supply (not shown) with respect to 1st semiconductor switch S1 and 2nd semiconductor switch S2. Therefore, only one gate drive power source is required for the first semiconductor switch S1 and the second semiconductor switch S2.

  Next, an example of control by the control device 20 of the fourth, fifth, and sixth semiconductor switches S4, S5, and S6 will be described.

  In the present embodiment, in the case where a current flows through the inductor L, the fourth, fifth and sixth semiconductor switches S4, S5, S6 when all the fourth to sixth semiconductor switches S4 to S6 are turned off. As a result, a high voltage may be applied to the semiconductor switch, which may destroy any of the fourth, fifth, and sixth semiconductor switches S4, S5, and S6.

  From this point of view, the DC-DC converter circuit 10 includes a protection function for performing the first to third control examples of the next switching operation by the control device 20.

  In the following first to third control examples, the current flowing through the inductor L can be measured with an ammeter not shown. The control device 20 can recognize whether or not a current is flowing through the inductor L based on the detection result of the ammeter.

[First control example]
In the first control example, when current flows through the inductor L, the control device 20 always turns on one or more semiconductor switches among the fourth to sixth semiconductor switches S4 to S6. The control voltage of the fourth to sixth semiconductor switches S4 to S6 is controlled.

  By doing so, when a current flows through the inductor L, a current path including the inductor L can be secured.

  For example, in the case where a current flows through the inductor L, if only the fifth semiconductor switch S5 is in the on state, the third current path R3 (FIG. 2C) is formed.

  For example, in the case where a current is flowing through the inductor L, if only the fourth semiconductor switch S4 is in an on state, a sixth current path R6 (see FIG. 3C) is formed.

  Further, for example, in the case where a current flows through the inductor L, if only the sixth semiconductor switch S6 is in an on state, an eighth current path R8 (FIG. 4B) is formed.

  As described above, in the first control example, it is possible to avoid that the fourth to sixth semiconductor switches S4 to S6 are all turned off, and accordingly, the fourth, fifth and sixth semiconductor switches S4, S5 and S5 due to the high voltage are avoided. The breakdown of any semiconductor switch in S6 can be prevented.

[Second control example]
In the second control example, when a current flows through the inductor L, the control device 20 before turning off one or two of the fourth to sixth semiconductor switches S4 to S6, Control of the fourth to sixth semiconductor switches S4 to S6 so that at least one of the fourth to sixth semiconductor switches S4 to S6 other than the semiconductor switch to be turned off is turned on in advance. The voltage is controlled.

  By doing so, when a current flows through the inductor L, a current path including the inductor L can be secured.

  For example, when a current flows through the inductor L, the other fifth semiconductor switches S5 are turned on in advance before the fourth and sixth semiconductor switches S4 and S6 to be turned off are turned off. Assuming and assuming that the first and second semiconductor switches S1 and S2 are in the OFF state, an eighth current path R8 (see FIG. 4B) is formed.

  As described above, in the second control example, it is possible to avoid that the fourth to sixth semiconductor switches S4 to S6 are all turned off, and accordingly, the fourth, fifth and sixth semiconductor switches S4, S5 and S5 due to the high voltage are avoided. The breakdown of any semiconductor switch in S6 can be prevented.

[Third control example]
In the third control example, the control device 20 is in the ON state of the first, second, fourth, fifth, and sixth semiconductor switches S1, S2, S4, S5, and S6 in a state where a current flows through the inductor L. In the case of changing the operation mode indicating the off state, all semiconductor switches that are turned on in the operation mode before the change are turned on for a certain time after the operation mode is changed, or the operation mode after the change is performed. The first, second, fourth, fifth and sixth semiconductor switches S1, S2, S4, S5, S6 so that all the semiconductor switches that are turned on at a predetermined time are turned on for a certain period of time before the operation mode is changed. The control voltage is controlled.

  8 and 9 are state transition diagrams illustrating an example in the case where the operation mode is changed from one mode to another mode among the first to ninth modes in the third control example.

  FIG. 8A shows the state of the first mode, and FIG. 8B shows the transition from the first mode to the second mode, which is an example when the current path in the commutation state is one. The flow state is shown, and FIG. 8C shows the state of the second mode.

  In the state shown in FIG. 8A, the first current path R1 (see FIG. 2A) is formed in the first mode.

  Next, in the state shown in FIG. 8B, all the semiconductor switches (in this case, the first and sixth semiconductor switches S1 and S6) that are in the on state in the operation mode before the change are in a certain time after the change of the operation mode. Turns on. Alternatively, all the semiconductor switches (in this case, the first and fifth semiconductor switches S1 and S5) that are turned on in the changed operation mode are turned on for a predetermined time before the operation mode is changed. At this time, the first, fifth, and sixth semiconductor switches S1, S5, and S6 are turned on, and as a result, the first current path R1 (see FIG. 2A) is formed.

  In the state shown in FIG. 8C, the second mode is established, and the second current path R2 (see FIG. 2B) is formed.

  FIG. 9A shows the state of the first mode, and FIG. 9B shows two current paths in the commutation state. The output voltage V1 of the first voltage source E1 and the second voltage source FIG. 9C shows the commutation state from the first mode to the fifth mode, which is an example of the case where the current path differs depending on the magnitude relationship between the output voltage V2 of E2 and FIG. 9C shows the state of the fifth mode. ing.

  In the state shown in FIG. 9A, the first current path R1 (see FIG. 2A) is formed in the first mode.

  Next, in the state shown in FIG. 9B, all the semiconductor switches (in this case, the first and sixth semiconductor switches S1 and S6) that are in the on state in the operation mode before the change are in a certain time after the change of the operation mode. Turns on. Alternatively, all the semiconductor switches (in this case, the second and fourth semiconductor switches S2 and S4) that are turned on in the changed operation mode are turned on for a predetermined time before the operation mode is changed. At this time, the first, second, fourth, and sixth semiconductor switches S1, S2, S4, and S6 are turned on, and the output voltage V1 of the first voltage source E1 is larger than the output voltage V2 of the second voltage source E2. The first current path R1 (see FIG. 2A) is formed, and the fourth current path R4 (see FIG. 2) when the output voltage V1 of the first voltage source E1 is smaller than the output voltage V2 of the second voltage source E2. 3 (a)) is formed.

  In the state shown in FIG. 9C, the fifth mode is set, and the second current path R5 (see FIG. 3B) is formed.

  As described above, in the third control example, it is possible to avoid that the fourth to sixth semiconductor switches S4 to S6 are all turned off, and accordingly, the fourth, fifth and sixth semiconductor switches S4, S5 and S5 due to the high voltage are avoided. The breakdown of any semiconductor switch in S6 can be prevented.

DESCRIPTION OF SYMBOLS 10 DC-DC converter circuit 20 Control apparatus D1-D8 1st-8th diode D10-D16 10th-16th diode E1 1st voltage source E2 2nd voltage source L Inductors S1-S2 1st and 2nd semiconductor switch S4 ~ S6 4th to 6th semiconductor switches

Claims (6)

Each including first, second, fourth, fifth and sixth semiconductor switches capable of passing current in one direction, a third diode, and an inductor;
The first and second semiconductor switches and the third diode are both connected in a direction in which current flows into one end of the inductor,
Each of the fourth to sixth semiconductor switches is connected in a direction in which current flows out to the other end of the inductor,
The anode side of the first voltage source is connected to the opposite end to the connection end of the inductor of the first and fourth semiconductor switches,
The anode side of the second voltage source is connected to the opposite end of the second and fifth semiconductor switches to the connection end of the inductor;
Both the cathode side of the first voltage source and the cathode side of the second voltage source are connected to ends of the third diode and the sixth semiconductor switch opposite to the connection ends of the inductors. A DC-DC converter circuit that is characterized. The DC-DC converter circuit according to claim 1,
Said first, second, fourth, fifth and sixth semiconductor switches allow said current to flow in a direction opposite to the direction in which the current can be turned on and off, respectively. , First, second, fourth, fifth and sixth diodes connected in parallel to the fifth and sixth semiconductor switches;
Between the first, second, fourth, fifth and sixth semiconductor switches and the inductor, current flows in the opposite direction to the first, second, fourth, fifth and sixth diodes, respectively. A DC-DC converter circuit, further comprising seventh, eighth, tenth, eleventh and twelfth diodes connected so as to be able to flow. The DC-DC converter circuit according to claim 1,
The first and second semiconductor switches are connected in parallel to the first and second semiconductor switches so that the current can flow in a direction opposite to the direction in which the current can be controlled on and off, respectively. Two diodes;
A fourth diode connected between the first semiconductor switch and the anode side of the first voltage source so that a current can flow in a direction opposite to that of the first diode;
A fifth diode connected between the second semiconductor switch and the anode side of the second voltage source so as to allow a current to flow in a direction opposite to that of the second diode; A DC-DC converter circuit characterized by comprising: A DC-DC converter circuit according to any one of claims 1 to 3,
A DC-DC converter comprising means for always turning on one or more of the fourth to sixth semiconductor switches when a current flows through the inductor. circuit. A DC-DC converter circuit according to any one of claims 1 to 4,
When a current flows through the inductor, before turning one or two of the fourth to sixth semiconductor switches off, the fourth to sixth semiconductor switches A DC-DC converter circuit comprising means for previously turning on at least one of the semiconductor switches other than the semiconductor switch to be turned off. A DC-DC converter circuit according to any one of claims 1 to 5,
When the operation mode indicating the on state and the off state of the first, second, fourth, fifth, and sixth semiconductor switches is changed in a state where a current flows through the inductor, the operation before the change All semiconductor switches that are turned on in the mode are turned on for a certain period of time after the operation mode is changed, or all semiconductor switches that are turned on in the changed operation mode are turned on for a certain period of time before the operation mode is changed. A DC-DC converter circuit comprising means for achieving the above.

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