Vehicle mounted converter

PRIORITY INFORMATION

p-0002This application claims priority to Japanese Patent Application No. 2009-066682 filed on Mar. 18, 2009, which is incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

p-00031. Field of the Invention

p-0004The present invention relates to a vehicle mounted converter including a plurality of inductors for performing switching of currents flowing to the inductors.

p-00052. Description of Related Art

p-0006Hybrid automobiles and electric automobiles traveling by the driving force of a motor are widely used. These motor driven vehicles include a battery for supplying the driving power to the motor and a booster converter for boosting a battery voltage and outputting the boosted voltage to a motor drive circuit.

p-0007The booster converter includes inductors and switching circuits for switching currents flowing to the inductors. The inductors generate an induced electromotive force by switching of the currents. The booster converter outputs to the motor drive circuit a boosted voltage where the induced electromotive force has been added to an input voltage. As a result, the booster converter can output a voltage higher than the battery voltage to the motor drive circuit.

p-0008In recent years, external charging devices for vehicle mounting have been developed for charging a battery by supplying power to the battery from a commercial power supply receptacle or other external power supply device. However, when mounting an external charging device in addition to a battery and booster converter to a vehicle, there was a problem with the increase in size of the system.

p-0009For example, Japanese Patent Laid-Open Publication No. Hei 8-308255 discloses a device for performing external charging using part of a vehicle mounted inverter, which performs direct current to alternating current conversion. An external charging circuit using part of the inverter is configured in this device and the addition of a large inductor is considered necessary.

p-0010The present invention solves this problem, namely, by miniaturizing the device size for a vehicle mounted power supply device having an external charging function.

SUMMARY OF THE INVENTION

p-0011The present invention is a vehicle mounted converter including a plurality of inductors; a switching unit for switching a current path; an external power acquisition unit for acquiring alternating current power from a power generating source provided separately from a mounted vehicle; and a switching means for switching a connection state of inductors, the switching unit, and the external power acquisition unit to a connection state of either a boost connection state for connecting one end of each inductor to a path to a battery for vehicle drive power supply and connecting the other end of each inductor to the switching unit, or a charging connection state for connecting one end of one of the plurality of inductors to the path to the battery, disconnecting one end of remaining inductors from the path to the battery and connecting to the external power acquisition unit, and connecting the other end of each inductor to the switching unit; wherein the switching unit, when the switching means sets the connection state to the boost connection state, outputs from the vehicle mounted converter a voltage based on an induced electromotive force generated at the inductors in accordance with current path switching and an output voltage of the battery; when the switching means sets the connection state to the charging connection state, converts an alternating current voltage output from the external power acquisition unit to a direct current voltage on the basis of current path switching and applies the direct current voltage thereof to the battery.

p-0012Furthermore, in the vehicle mounted converter relating to the present invention, it is preferable to include a drive circuit for controlling the drive motor of the mounted vehicle, wherein the switching means connects the drive circuit to the switching unit so that a voltage based on induced electromotive force generated at the inductors and the output voltage of the battery is output to the drive circuit when the connection state is set to the boost connection state; and disconnects the drive circuit from the switching unit when the connection state is set to the charging connection state.

p-0013Furthermore, the present invention is a vehicle mounted converter including a plurality of inductors; a switching unit for switching a current path; an external power acquisition unit for acquiring alternating current power from a power generation source provided separately from the mounted vehicle; and a switching means for switching the connection state of the inductors, the switching unit, and the external power acquisition unit to a boost connection state for connecting one end of each inductor to a path to a battery for vehicle drive power supply and connecting the other end of each inductor to the switching unit, or to a charging connection state for disconnecting one end of each inductor from the path to the battery, connecting one end of one of the plurality of inductors to the external power acquisition unit as well as connecting the other end thereof to a front-stage section of the switching unit, and further connecting the remaining inductors to the switching unit so that a magnetically coupled circuit is formed for magnetically coupling the front-stage section and a back-stage section of the switching unit; wherein the switching unit outputs a voltage based on induced electromotive force generated at the inductors in accordance with current path switching and an output voltage of the battery when the switching means sets the connection state to the boost connection state; and converts an alternating current voltage output from the external power acquisition unit to a direct current voltage based on current path switching and applies the direct current voltage thereof from the back-stage section to the battery when the switching means sets the connection state to the charging connection state.

p-0014Furthermore, in the vehicle mounted converter relating to the present invention, it is preferable to further include a drive circuit for controlling a drive motor of the mounted vehicle connected to the back-stage section, wherein when the switching means sets the connection state to the boost connection state, a voltage based on induced electromotive force generated at the inductors and the output voltage of the battery is output from the switching unit to the drive circuit.

p-0015According to the present invention, device size can be miniaturized for a vehicle mounted power supply device having an external charging function.

BRIEF DESCRIPTION OF THE DRAWINGS

p-0016<figref idrefs="DRAWINGS">FIG. 1</figref> shows a configuration of a hybrid vehicle drive system relating to a first embodiment.

p-0017<figref idrefs="DRAWINGS">FIG. 2</figref> shows an example configuration of a switching device.

p-0018<figref idrefs="DRAWINGS">FIG. 3</figref> shows a circuit configuration of a three-phase multiphase converter in an external charging mode.

p-0019<figref idrefs="DRAWINGS">FIG. 4</figref> shows a configuration of a hybrid vehicle drive system relating to an application example of the first embodiment.

p-0020<figref idrefs="DRAWINGS">FIG. 5</figref> shows a circuit configuration of a four-phase multiphase converter relating to an application example in the external charging mode.

p-0021<figref idrefs="DRAWINGS">FIG. 6</figref> shows a configuration of a hybrid vehicle drive system relating to a second embodiment.

p-0022<figref idrefs="DRAWINGS">FIG. 7</figref> shows a circuit configuration of a six-phase multiphase converter in the external charging mode.

p-0023<figref idrefs="DRAWINGS">FIG. 8</figref> shows a configuration of a hybrid vehicle drive system relating to an application example of the second embodiment.

p-0024<figref idrefs="DRAWINGS">FIG. 9</figref> shows a circuit configuration of a seven-phase multiphase converter relating to an application example in the external charging mode.

DETAILED DESCRIPTION OF THE INVENTION

p-0025<figref idrefs="DRAWINGS">FIG. 1</figref> shows a configuration of a hybrid vehicle drive system <b>10</b> relating to the first embodiment of the present invention. The hybrid vehicle drive system <b>10</b> includes a switching three-phase multiphase converter <b>12</b>. The switching three-phase multiphase converter <b>12</b> charges a battery <b>14</b> for vehicle drive power supply on the basis of power obtained from an external power supply device, such as a commercial power supply, or boosts and outputs the output voltage of the battery <b>14</b> to a drive circuit <b>20</b>. Furthermore, the drive circuit <b>20</b>, a drive motor <b>22</b>, and a power generation motor <b>24</b> are provided, where the drive circuit <b>20</b> performs direct current to alternating current conversion and transfers power between the switching three-phase multiphase converter <b>12</b> and the drive motor <b>22</b> as well as the power generation motor <b>24</b>.

p-0026The switching three-phase multiphase converter <b>12</b> has a configuration where inductors are connected to connection nodes between the switching devices connected at the top and bottom. The switching three-phase multiphase converter <b>12</b> operates in either a boost mode for boosting the output voltage of the battery <b>14</b> or an external charging mode for charging the battery <b>14</b> on the basis of power obtained from an external power supply device.

p-0027An input capacitor <b>16</b> is connected in parallel with both ends of the battery <b>14</b>. To the positive electrode of the battery <b>14</b> is connected one end of a relay switch RS<b>1</b>, one end of a relay switch RS<b>2</b>, and one end of an inductor L<b>3</b>.

p-0028The other ends of the relay switches RS<b>1</b> and RS<b>2</b> are respectively connected to one end of inductors L<b>1</b> and L<b>2</b>. The other end of the inductor L<b>1</b> is connected to the connection node between the switching devices S<b>1</b> and S<b>2</b>, and the other end of the inductor L<b>2</b> is connected to the connection node between the switching devices S<b>3</b> and S<b>4</b>. Furthermore, the other end of the inductor L<b>3</b> is connected to the connection node between the switching devices S<b>5</b> and S<b>6</b>.

p-0029One end of the switching device S<b>1</b> opposite to the switching device S<b>2</b> side, one end of the switching device S<b>3</b> opposite to the switching device S<b>4</b> side, and one end of the switching device S<b>5</b> opposite to the switching device S<b>6</b> side are connected in common to one end of a relay switch RS<b>3</b>. The other end of the relay switch RS<b>3</b> is connected to the drive circuit <b>20</b>.

p-0030One end of the switching device S<b>2</b> opposite to the switching device S<b>1</b> side, one end of the switching device S<b>4</b> opposite to the switching device S<b>3</b> side, and one end of the switching device S<b>6</b> opposite to the switching device S<b>5</b> side are connected in common to the negative electrode of the battery <b>14</b> and to a relay switch RS<b>4</b>. The other end of the relay switch RS<b>4</b> is connected to the drive circuit <b>20</b>. To the drive circuit <b>20</b> are connected the drive motor <b>22</b> and the power generation motor <b>24</b>.

p-0031An output capacitor <b>18</b> is connected between the common connection node of the switching devices S<b>1</b>, S<b>3</b>, and S<b>5</b> and the common connection node of the switching devices S<b>2</b>, S<b>4</b>, and s<b>6</b>.

p-0032A single-phase power supply plug <b>26</b> is connected between the connection node of the relay switch RS<b>1</b> and the inductor L<b>1</b> and the connection node of the relay switch RS<b>2</b> and the inductor L<b>2</b>.

p-0033The switching devices S<b>1</b> to S<b>6</b> and the relay switches RS<b>1</b> to RS<b>4</b> are controlled to turn on or off by a controller <b>28</b>. Semiconductor devices, such as insulated gate bipolar transistors (IGBT), other common bipolar transistors, field effect transistors, and so forth, can be used for the switching devices S<b>1</b> to S<b>6</b>. The same applies to other switching devices described hereinafter. When using IGBTs as the switching devices, the IGBTs are connected at the connected positions of the switching devices so that the collector terminals are on the upper side in <figref idrefs="DRAWINGS">FIG. 1</figref> and the emitter terminals are on the lower side. Then, between the collector terminal and the emitter terminal of each IGBT is connected a diode so that the anode terminal is on the emitter terminal side. In this case, a current in the direction of emitter terminal to collector terminal flows through the diode due to the diode being forward biased. <figref idrefs="DRAWINGS">FIG. 2</figref> shows that an IGBT <b>32</b> and a diode <b>34</b> shown on the right side can be used as a switching device <b>30</b> shown on the left side.

p-0034An operation of the boost mode will be described. In the boost mode, the controller <b>28</b> turns on the relay switches RS<b>1</b> to RS<b>4</b>. Then, the next control is performed so that a voltage, which is the output voltage of the battery <b>14</b> that has been boosted, is output as the output voltage of the switching three-phase multiphase converter <b>12</b> to the drive circuit <b>20</b>.

p-0035Of the two switching devices connected at the top and bottom, when the upper switching device is turned off and the lower switching device is turned on, current flows from the positive electrode of the battery <b>14</b> to the lower switching device via the inductor connected to the upper and lower switching devices. When the lower switching device is turned off in this state, an induced electromotive force is generated at the inductor. At this time, by turning on the upper switching device, a voltage where the induced electromotive force has been added to the output voltage of the battery <b>14</b> is applied to both ends of the output capacitor <b>18</b> and the drive circuit <b>20</b>.

p-0036When the voltage where the induced electromotive force has been added to the output voltage of the battery <b>14</b> is greater than or equal to the voltage between terminals of the output capacitor <b>18</b>, the output capacitor <b>18</b> is charged or the charged voltage of the output capacitor <b>18</b> is maintained. As a result, a voltage higher than the output voltage of the battery <b>14</b> can be output to the drive circuit <b>20</b>.

p-0037When the voltage where the induced electromotive force has been added to the output voltage of the battery <b>14</b> is lower than the voltage between terminals of the output capacitor <b>18</b>, current flows from the output capacitor <b>18</b> and the drive circuit <b>20</b> to the battery <b>14</b> and the input capacitor <b>16</b> via the upper switching device that is on and the inductor connected thereto. As a result, the battery <b>14</b> and the input capacitor <b>16</b> can be charged. The input capacitor <b>16</b> reduces the ripple component included in the output voltage of the battery <b>14</b> due to charging and discharging.

p-0038On the basis of this principle, the controller <b>28</b> controls the switching devices S<b>1</b> to S<b>6</b> so that a voltage where the inductor induced electromotive force has been added to the output voltage of the battery <b>14</b> is applied to the output capacitor <b>18</b> and the voltage between terminals of the output capacitor <b>18</b> is output to the drive circuit <b>20</b>. The induced electromotive force generated at each inductor can be adjusted by varying the switching timing of each switching device.

p-0039The controller <b>28</b> adjusts the switching timing of each switching device in accordance with travel control so that a direct current voltage is output from the switching three-phase multiphase converter <b>12</b> to the drive circuit <b>20</b> in accordance with travel control of the mounted vehicle.

p-0040This embodiment has a configuration using three pairs of switching devices connected at the top and bottom. As a result, compared to the case using one or two pairs of upper and lower switching devices, the ripple component included in the direct current voltage that is output to the drive circuit <b>20</b> can be reduced.

p-0041The drive circuit <b>20</b> includes an inverter for performing direct current to alternating current conversion based on switching. The drive circuit <b>20</b> performs direct current to alternating current conversion between the switching three-phase multiphase converter <b>12</b> and the drive motor <b>22</b>. In accordance with the magnitude relationship between the output voltage of the switching three-phase multiphase converter <b>12</b> and the voltage between terminals of the drive motor <b>22</b>, the drive circuit <b>20</b> converts the direct current power, which the switching three-phase multiphase converter <b>12</b> outputs, to alternating current power and supplies the alternating current power thereof to the drive motor <b>22</b>. Furthermore, in accordance with the magnitude relationship between the output voltage of the switching three-phase multiphase converter <b>12</b> and the voltage between terminals of the drive motor <b>22</b>, the generated power from the drive motor <b>22</b> is converted to direct current power and the direct current power thereof is supplied to the switching three-phase multiphase converter <b>12</b>.

p-0042Similarly, the drive circuit <b>20</b> performs direct current to alternating current conversion between the switching three-phase multiphase converter <b>12</b> and the power generation motor <b>24</b>. In accordance with the magnitude relationship between the output voltage of the switching three-phase multiphase converter <b>12</b> and the voltage between terminals of the power generation motor <b>24</b>, the drive circuit <b>20</b> converts the direct current power, which the switching three-phase multiphase converter <b>12</b> outputs, to alternating current power, and outputs the alternating current power thereof to the power generation motor <b>24</b>. Furthermore, in accordance with the magnitude relationship between the output voltage of the switching three-phase multiphase converter <b>12</b> and the voltage between terminals of the power generation motor <b>24</b>, the generated power from the power generation motor <b>24</b> is converted to direct current power and the direct current power thereof is supplied to the switching three-phase multiphase converter <b>12</b>.

p-0043The drive motor <b>22</b> drives the mounted vehicle or performs regenerative dynamic braking. The power generation motor <b>24</b> performs power generation depending on the engine drive power or starting of the engine.

p-0044Next, an operation of the external charging mode will be described. The controller <b>28</b> controls the relay switches RS<b>1</b> to RS<b>4</b> to turn off. This results in the circuit configuration shown in <figref idrefs="DRAWINGS">FIG. 3</figref>. The same reference numerals have been applied to parts identical to those shown in <figref idrefs="DRAWINGS">FIG. 1</figref>.

p-0045The single-phase power supply plug <b>26</b> is inserted into a single-phase power supply receptacle. One electrode of the single-phase power supply plug <b>26</b> is connected to one end of the inductor L<b>1</b> on the relay switch RS<b>1</b> side and the other electrode of the single-phase power supply plug <b>26</b> is connected to one end of the inductor L<b>2</b> on the relay switch RS<b>2</b> side.

p-0046From the single-phase power supply plug <b>26</b> and via the inductors L<b>1</b> and L<b>2</b> a single-phase alternating current voltage is applied between a connection node A of the switching devices S<b>1</b> and S<b>2</b> and a connection node B of the switching devices S<b>3</b> and S<b>4</b>. The controller <b>28</b> operates the switching devices S<b>1</b> to S<b>4</b> as a single-phase inverter. Namely, PWM (Pulse Width Modulation) control is performed for the switching devices S<b>1</b> to S<b>4</b>, rectification and boosting of the alternating current voltage between connection nodes A and B are performed, and the resulting obtained direct current voltage is applied to the output capacitor <b>18</b>.

p-0047When the voltage between electrodes of the single-phase power supply plug <b>26</b> is V sin(ωt) (where V is voltage amplitude, ω is angular frequency, and t is time), for example, the controller <b>28</b> controls the switching devices S<b>1</b> to S<b>4</b> so that the voltage between terminals of the inductor L<b>1</b> based on the single-phase power supply plug <b>26</b> side and the voltage between terminals of the inductor L<b>2</b> based on the connection node B side become (½)B cos(ωt) (where B is voltage amplitude). Since current flowing through each inductor is an integral value of the terminal voltage, current flowing out from one end and flowing into another end of the single-phase power supply plug <b>26</b> at this time has the same phase as the voltage between electrodes of the single-phase power supply plug <b>26</b>. As a result, the power factor between electrodes of the single-phase power supply plug <b>26</b> can be set as 1 and the withstand voltage and the withstand current of each part of the switching three-phase multiphase converter <b>12</b> can be suppressed to necessary minimum values. Furthermore, due to the induced electromotive force of the inductors L<b>1</b> and L<b>2</b>, a voltage higher than the voltage amplitude between electrodes of the single-phase power supply plug <b>26</b> can be applied to the output capacitor <b>18</b>.

p-0048The controller <b>28</b> performs the next control so that the voltage between terminals of the output capacitor <b>18</b> drops and the input capacitor <b>16</b> and the battery <b>14</b> are charged by the voltage after the drop.

p-0049When the switching device S<b>6</b> is turned on and the switching device S<b>5</b> is turned off, current flows from the positive electrode of the battery <b>14</b> to the switching device S<b>6</b> via the inductor L<b>3</b>. When the switching device S<b>6</b> is turned off in this state, an induced electromotive force is generated at the inductor L<b>3</b>. At this time, when a voltage where the induced electromotive force of the inductor L<b>3</b> has been added to the output voltage of the battery <b>14</b> is lower than the voltage between terminals of the output capacitor <b>18</b>, turning on the switch S<b>5</b> causes electric charge to be discharged from the output capacitor <b>18</b> via the inductor L<b>3</b> to the input capacitor <b>16</b> and the battery <b>14</b> so that the input capacitor <b>16</b> and the battery <b>14</b> can be charged.

p-0050On the basis of this principle, the controller <b>28</b> controls the switching devices S<b>5</b> and S<b>6</b> so that electric charge is discharged from the output capacitor <b>18</b> to the input capacitor <b>16</b> and the battery <b>14</b> thereby charging the input capacitor <b>16</b> and the battery <b>14</b>. As a result, the switching three-phase multiphase converter <b>12</b> can obtain alternating current power from the external power supply device and charge the battery <b>14</b>.

p-0051According to this configuration, the inductors L<b>1</b> and L<b>2</b>, which are used as boost inductors in the boost mode, can be used as power factor improvement and boost inductors in the external charging mode. Furthermore, the inductor L<b>3</b>, which is used as a boost inductor in the boost mode, can be used as a voltage drop inductor in the external charging mode. As a result, parts used in the boost mode can be used in the external charging mode so that the size of the system can be miniaturized.

p-0052Next, an application example of the first embodiment will be described. <figref idrefs="DRAWINGS">FIG. 4</figref> shows a configuration of a hybrid vehicle drive system <b>36</b> relating to the application example. The same reference numerals have been applied to parts identical to those shown in <figref idrefs="DRAWINGS">FIG. 1</figref> and the descriptions thereof will be omitted.

p-0053The hybrid vehicle drive system <b>36</b> includes a switching four-phase multiphase converter <b>38</b>. The switching four-phase multiphase converter <b>38</b> adds an inductor L<b>4</b>, a relay switch RS<b>5</b>, and switching devices SA<b>1</b> and SA<b>2</b> to the switching three-phase multiphase converter <b>12</b> of <figref idrefs="DRAWINGS">FIG. 1</figref> and enables the charging of the battery <b>14</b> with three-phase alternating current in the external charging mode.

p-0054One end of the relay switch RS<b>5</b> is connected to the positive electrode of the battery <b>14</b>. The other end of the relay switch RS<b>5</b> is connected to one end of the inductor L<b>3</b>. The other end of the inductor L<b>3</b> is connected to the connection node between the switching devices S<b>5</b> and S<b>6</b>.

p-0055One end of the inductor L<b>4</b> is connected to the positive electrode of the battery <b>14</b>. The other end of the inductor L<b>4</b> is connected to the connection node between the switching devices SA<b>1</b> and SA<b>2</b>. One end of the switching device SA<b>1</b> opposite to the switching device SA<b>2</b> side is connected to a common connection node of the switching devices S<b>1</b>, S<b>3</b>, and S<b>5</b>. One end of the switching device SA<b>2</b> opposite to the switching device SA<b>1</b> side is connected to a common connection node of the switching devices S<b>2</b>, S<b>4</b>, and S<b>6</b>.

p-0056A three-phase power supply plug <b>40</b> is connected to the connection node between the relay switch RS<b>1</b> and the inductor L<b>1</b>, the connection node between the relay switch RS<b>2</b> and the inductor L<b>2</b>, and the connection node between the relay switch RS<b>5</b> and the inductor L<b>3</b>.

p-0057When using IGBTs as switching devices SA<b>1</b> and SA<b>2</b>, the IGBTs are connected at the connected positions of the switching devices so that the collector terminals are on the upper side in <figref idrefs="DRAWINGS">FIG. 4</figref> and the emitter terminals are on the lower side. Then, between the collector terminal and the emitter terminal of each IGBT is connected a diode so that the anode terminal is on the emitter terminal side.

p-0058An operation in the boost mode will be described. In the boost mode, a controller <b>42</b> controls the relay switches RS<b>1</b> to RS<b>5</b> to turn on.

p-0059The controller <b>42</b> controls the switching devices S<b>1</b> to S<b>6</b>, SA<b>1</b>, and SA<b>2</b> so that a voltage where the inductor induced electromotive force has been added to the output voltage of the battery <b>14</b> is applied to the output capacitor <b>18</b> and the drive circuit <b>20</b> based on the same control principle with respect to the switching devices connected at the top and bottom in the switching three-phase multiphase converter <b>12</b>. The induced electromotive force generated at each inductor can be adjusted by varying the switching timing of each switching device.

p-0060The controller <b>42</b> adjusts the switching timing of the switching devices in accordance with travel control so that a direct current voltage in accordance with travel control of the mounted vehicle is output from the switching four-phase multiphase converter <b>38</b> to the drive circuit <b>20</b>.

p-0061This embodiment has a configuration using four pairs of switching devices connected at the top and bottom. As a result, compared to the case using less than four pairs of upper and lower switching devices, the ripple component included in the direct current voltage that is output to the drive circuit <b>20</b> can be reduced.

p-0062The drive circuit <b>20</b> performs direct current to alternating current conversion and power transfers between the switching four-phase multiphase converter <b>38</b> and the drive motor <b>22</b> as well as the power generation motor <b>24</b>.

p-0063Next, an operation of the external charging mode will be described. The controller <b>42</b> controls the relay switches RS<b>1</b> to RS<b>5</b> to turn off. This results in the circuit configuration shown in <figref idrefs="DRAWINGS">FIG. 5</figref>. The same reference numerals have been applied to parts identical to those shown in <figref idrefs="DRAWINGS">FIG. 4</figref>.

p-0064The three-phase power supply plug <b>40</b> is inserted into a three-phase power supply receptacle. A first electrode of the three-phase power supply plug <b>40</b> is connected to one end of the inductor L<b>1</b> on the relay switch RS<b>1</b> side and a second electrode of the three-phase power supply plug <b>40</b> is connected to one end of the inductor L<b>2</b> on the relay switch RS<b>2</b> side. Furthermore, a third electrode of the three-phase power supply plug <b>40</b> is connected to one end of the inductor L<b>3</b> on the relay switch RS<b>5</b> side.

p-0065A three-phase alternating current voltage is applied from the three-phase power supply plug <b>40</b> via the inductors L<b>1</b>, L<b>2</b>, and L<b>3</b> to the connection node A between the switching devices S<b>1</b> and S<b>2</b>, the connection node B between the switching devices S<b>3</b> and S<b>4</b>, and a connection node C between the switching devices S<b>5</b> and S<b>6</b>. The controller <b>42</b> operates the switching devices S<b>1</b> to S<b>6</b> as a three-phase inverter. Namely, PWM control of the switching devices S<b>1</b> to S<b>6</b> is performed and interphase voltages mutually between the connection nodes A, B, and C are rectified and boosted so that the resulting direct current voltage is applied to the output capacitor <b>18</b>.

p-0066When the voltages with respect to the neutral point voltage of the first to third electrodes of the three-phase power supply plug <b>40</b> are V sin(ωt), V sin(ωt+120°), and V sin(ωt+240°), respectively, for example, the controller <b>42</b> controls the switching devices S<b>1</b> to S<b>6</b> so that currents flowing into the first to third electrodes are I sin(ωt), I sin(ωt+120°), and I sin(ωt+240°), respectively (where I is current amplitude). As a result, the power factor between electrodes of the three-phase power supply plug <b>40</b> can be set to 1 and the withstand voltage and the withstand current of each part of the switching four-phase multiphase converter <b>38</b> can be suppressed to necessary minimum values. Furthermore, due to the induced electromotive force of the inductors L<b>1</b> to L<b>3</b>, a voltage higher than the voltage amplitude between electrodes of the three-phase power supply plug <b>40</b> can be applied to the output capacitor <b>18</b>.

p-0067Similar to the control with respect to the switching three-phase multiphase converter <b>12</b> of <figref idrefs="DRAWINGS">FIG. 3</figref>, the controller <b>42</b> controls the switching devices SA<b>1</b> and SA<b>2</b> so that electric charge is discharged from the output capacitor <b>18</b> to the input capacitor <b>16</b> and the battery <b>14</b> thereby charging the input capacitor <b>16</b> and the battery <b>14</b>. Here, the inductor L<b>4</b> of <figref idrefs="DRAWINGS">FIG. 5</figref> has the same function as the inductor L<b>3</b> of <figref idrefs="DRAWINGS">FIG. 3</figref>. As a result, the switching four-phase multiphase converter <b>38</b> can obtain three-phase alternating current power from the external power supply device and charge the battery <b>14</b>.

p-0068According to this configuration, the inductors L<b>1</b> to L<b>3</b>, which are used as boost inductors in the boost mode, can be used as power factor improvement and boost inductors in the external charging mode. Furthermore, the inductor L<b>4</b> used as a boost inductor in the boost mode can be used as a voltage drop inductor in the external charging mode. As a result, parts used in the boost mode can be used in the external charging mode so that the size of the system can be miniaturized.

p-0069<figref idrefs="DRAWINGS">FIG. 6</figref> shows a configuration of a hybrid vehicle drive system <b>44</b> relating to a second embodiment of the present invention. The hybrid vehicle drive system <b>44</b> includes a switching six-phase multiphase converter <b>46</b>. The switching six-phase multiphase converter <b>46</b> charges the battery <b>14</b> based on the electric power obtained from the external power supply device, such as a commercial power supply, or boosts and outputs the output voltage of the battery <b>14</b> to the drive circuit <b>20</b>. The same reference numerals have been applied to parts identical to those shown in <figref idrefs="DRAWINGS">FIG. 1</figref> and the descriptions thereof will be omitted.

p-0070The switching six-phase multiphase converter <b>46</b> has a configuration where inductors are connected to the connection nodes between the switching devices connected at the top and bottom. The switching six-phase multiphase converter <b>46</b> operates in either a boost mode for boosting the output voltage of the battery <b>14</b> or an external charging mode for charging the battery <b>14</b> on the basis of power obtained from an external power supply device.

p-0071Relay switches SW<b>1</b> to SW<b>4</b> have one end connected to the positive electrode of the battery <b>14</b>. To the other ends of the relay switches SW<b>1</b> and SW<b>2</b> are connected one end of the inductor L<b>1</b> and one end of the inductor L<b>2</b>, respectively. To the other end of the relay switch SW<b>3</b> are connected one end of the inductor L<b>3</b> and one end of the inductor L<b>4</b> and to the other end of the relay switch SW<b>4</b> are connected one end of an inductor L<b>5</b> and one end of an inductor L<b>6</b>.

p-0072The other end of the inductor L<b>1</b> is connected to the connection node between the switching devices S<b>1</b> and S<b>2</b> and the other end of the inductor L<b>2</b> is connected to the connection node between the switching devices S<b>3</b> and S<b>4</b>. Furthermore, the other end of the inductor L<b>3</b> is connected to the connection node between the switching devices S<b>5</b> and S<b>6</b> and the other end of the inductor L<b>4</b> is connected to the connection node between switching device S<b>7</b> and S<b>8</b>. Moreover, the other end of the inductor L<b>5</b> is connected to the connection node between switching devices S<b>9</b> and S<b>10</b> and the other end of the inductor L<b>6</b> is connected to the connection node between switching devices S<b>11</b> and S<b>12</b>.

p-0073One end of the switching device S<b>1</b> opposite to the switching device S<b>2</b> side, one end of the switching device S<b>3</b> opposite to the switching device S<b>4</b> side, one end of the switching device S<b>5</b> opposite to the switching device S<b>6</b> side, and one end of the switching device S<b>7</b> opposite to the switching device S<b>8</b> side are connected in common to one end of the relay switch SW<b>7</b>. The other end of the relay switch SW<b>7</b> is connected to the drive circuit <b>20</b>.

p-0074One end of the switching device S<b>2</b> opposite to the switching device S<b>1</b> side, one end of the switching device S<b>4</b> opposite to the switching device S<b>3</b> side, one end of the switching device S<b>6</b> opposite to the switching device S<b>5</b> side, and one end of the switching device S<b>8</b> opposite to the switching device S<b>7</b> side are connected in common to one end of a relay switch SW<b>6</b>. The other end of the relay switch SW<b>6</b> is connected to the negative electrode of the battery <b>14</b> and to the drive circuit <b>20</b>.

p-0075A front-stage output capacitor <b>18</b>-<b>1</b> is connected between a common connection node of the switching devices S<b>1</b>, S<b>3</b>, S<b>5</b>, and S<b>7</b> and a common connection node of the switching devices S<b>2</b>, S<b>4</b>, S<b>6</b>, and S<b>8</b>.

p-0076One end of the switching device S<b>9</b> opposite to the switching device S<b>10</b> side and one end of the switching device S<b>11</b> opposite to the switching device S<b>12</b> side are connected to the drive circuit <b>20</b>, one end of a relay switch SW<b>5</b>, and one end of a relay switch SW<b>7</b>. The other end of the relay switch SW<b>5</b> is connected to the positive electrode of the battery <b>14</b>.

p-0077One end of the switching device S<b>10</b> opposite to the switching device S<b>9</b> side and one end of the switching device S<b>12</b> opposite to the switching device S<b>11</b> side are connected to the negative electrode of the battery <b>14</b> and to the drive circuit <b>20</b>.

p-0078A back-stage output capacitor <b>18</b>-<b>2</b> is connected between a common connection node of the switching devices S<b>9</b> and S<b>11</b> and a common connection node of the switching devices S<b>10</b> and S<b>12</b>.

p-0079The single-phase power supply plug <b>26</b> is connected between a connection node of the relay switch SW<b>1</b> and the inductor L<b>1</b> and a connection node of the relay switch SW<b>2</b> and the inductor L<b>2</b>.

p-0080The inductors L<b>3</b> and L<b>5</b> magnetically couple so that when current flows toward a switching device through one inductor, an induced electromotive force is generated at the other inductor causing current to flow toward a switching device. The inductors L<b>4</b> and L<b>6</b> magnetically couple so that when current flows toward a switching device through one inductor, an induced electromotive is generated at the other inductor causing current to flow toward a switching device.

p-0081The switching devices S<b>1</b> to S<b>12</b> and the relay switches SW<b>1</b> to SW<b>7</b> are controlled to turn on or off by a controller <b>48</b>. When using IGBTs for the switching devices, the IGBTs are connected at the connected positions of the switching devices so that the collector terminals are on the upper side in <figref idrefs="DRAWINGS">FIG. 6</figref> and the emitter terminals are on the lower side. Then, between the collector terminal and the emitter terminal of each IGBT is connected a diode so that the anode terminal is on the emitter terminal side.

p-0082An operation of the boost mode will be described. In the boost mode, the controller <b>48</b> controls the relay switches SW<b>1</b> to SW<b>4</b>, SW<b>6</b>, and SW<b>7</b> to turn on and the relay switch SW<b>5</b> to turn off.

p-0083The controller <b>48</b> controls the switching devices S<b>1</b> to S<b>12</b> so that a voltage where the inductor induced electromotive force has been added to the output voltage of the battery <b>14</b> is applied to the front-stage output capacitor <b>18</b>-<b>1</b>, the back-stage output capacitor <b>18</b>-<b>2</b>, and the drive circuit <b>20</b> based on the same control principle with respect to the switching devices connected at the top and bottom in the switching three-phase multiphase converter <b>12</b> of <figref idrefs="DRAWINGS">FIG. 1</figref>. The induced electromotive force generated at each inductor can be adjusted by varying the switching timing of each switching device.

p-0084The controller <b>48</b> adjusts the switching timing of the switching devices in accordance with travel control so that a direct current voltage in accordance with travel control of the mounted vehicle is output from the switching six-phase multiphase converter <b>46</b> to the drive circuit <b>20</b>.

p-0085This embodiment has a configuration using six pairs of switching devices connected at the top and bottom. As a result, compared to the case using less than six pairs of upper and lower switching devices, the ripple component included in the direct current voltage that is output to the drive circuit <b>20</b> can be reduced.

p-0086The drive circuit <b>20</b> performs direct current to alternating current conversion and power transfers between the switching six-phase multiphase converter <b>46</b> and the drive motor <b>22</b> as well as the power generation motor <b>24</b>.

p-0087Next, an operation of the external charging mode will be described. The controller <b>48</b> controls the relay switches SW<b>1</b> to SW<b>4</b>, SW<b>6</b>, and SW<b>7</b> to turn off and SW<b>5</b> to turn on. This results in the circuit configuration shown in <figref idrefs="DRAWINGS">FIG. 7</figref>. The same reference numerals have been applied to parts identical to those shown in <figref idrefs="DRAWINGS">FIG. 6</figref>. In the external charging mode, the switching six-phase multiphase converter <b>46</b> is divided into parts in a stage before inductor L<b>3</b>+L<b>4</b> and parts in a stage after inductor L<b>5</b>+L<b>6</b>.

p-0088The single-phase power supply plug <b>26</b> is inserted into a single-phase power supply receptacle. One electrode of the single-phase power supply plug <b>26</b> is connected to one end of the inductor L<b>1</b> on the relay switch SW<b>1</b> side and the other electrode of the single-phase power supply plug <b>26</b> is connected to one end of the inductor L<b>2</b> on the relay switch SW<b>2</b> side. The drive circuit <b>20</b> is connected to the right side of the battery <b>14</b> in <figref idrefs="DRAWINGS">FIG. 7</figref>.

p-0089Similar to the embodiment shown in <figref idrefs="DRAWINGS">FIG. 3</figref>, the controller <b>48</b> operates the switching devices S<b>1</b> to S<b>4</b> as a single-phase inverter. As a result, an alternating current voltage between connection nodes A and B is rectified and boosted and the direct current voltage after rectification and boosting is applied to the front-stage output capacitor <b>18</b>-<b>1</b>.

p-0090The primary-side inductor L<b>3</b>+L<b>4</b> is connected between a connection node D of the switching devices S<b>5</b> and S<b>6</b> and a connection node E of the switching devices S<b>7</b> and S<b>8</b>.

p-0091The primary-side inductor L<b>3</b>+L<b>4</b> has inductors L<b>3</b> and L<b>4</b> connected in series. The secondary inductor L<b>5</b>+L<b>6</b> is connected between a connection node F of the switching devices S<b>9</b> and S<b>10</b> and a connection node G of the switching devices S<b>11</b> and S<b>12</b>. The secondary inductor L<b>5</b>+L<b>6</b> has the inductors L<b>5</b> and L<b>6</b> connected in series.

p-0092The controller <b>48</b> operates the switching devices S<b>5</b> to S<b>8</b> as a single-phase inverter. Namely, PWM control is performed for the switching devices S<b>5</b> to S<b>8</b>, the voltage between terminals of the front-stage output capacitor <b>18</b>-<b>1</b> is converted to an alternating current voltage, and the alternating current voltage thereof is applied to the primary-side inductor L<b>3</b>+L<b>4</b>. The magnetic coupling of the primary-side inductor L<b>3</b>+L<b>4</b> and the secondary-side inductor L<b>5</b>+L<b>6</b> causes an alternating current voltage to be generated at the secondary-side inductor L<b>5</b>+L<b>6</b> and the alternating current voltage thereof is applied between the connection node F and the connection node G.

p-0093The controller <b>48</b> operates the switching devices S<b>9</b> to S<b>12</b> as a single-phase inverter. Namely, PWM control of the switching devices S<b>9</b> to S<b>12</b> is performed, the alternating current voltage applied from the secondary-side inductor L<b>5</b>+L<b>6</b> to between the connection node F and the connection node G is rectified, and the direct current voltage after rectification is applied to the back-stage output capacitor <b>18</b>-<b>2</b>, the input capacitor <b>16</b>, and the battery <b>14</b>. As a result, the switching six-phase multiphase converter <b>46</b> can obtain power from the external power supply device and charge the battery <b>14</b>.

p-0094According to this configuration, the inductors L<b>1</b> and L<b>2</b>, which are used as boost inductors in the boost mode, can be used as power factor improvement and boost inductors in the external charging mode. As a result, parts used in the boost mode can be used in the external charging mode so that the size of the system can be miniaturized.

p-0095Furthermore, in the external charging mode, on the basis of the magnetic coupling of the primary-side inductor L<b>3</b>+L<b>4</b> and the secondary-side inductor L<b>5</b>+L<b>6</b>, the front-stage section and the back-stage section are coupled and electrically insulated. This makes it possible to avoid an application of a high voltage to the front-stage section, and during the handling of the single-phase power supply plug <b>26</b> in the front-stage section to avoid shortening of the system life, such as due to contact between parts being applied with high voltages.

p-0096Next, an application example of the second embodiment will be described. <figref idrefs="DRAWINGS">FIG. 8</figref> shows a configuration of a vehicle drive system <b>50</b> relating to the application example. The same reference numerals have been applied to parts identical to those shown in <figref idrefs="DRAWINGS">FIG. 6</figref> and the descriptions thereof will be omitted.

p-0097The hybrid vehicle drive system <b>50</b> includes a switching seven-phase multiphase converter <b>52</b>. The seven-phase multiphase converter <b>52</b> adds an inductor L<b>7</b>, a relay switch SW<b>8</b>, and switching devices SA<b>3</b> and SA<b>4</b> to the switching six-phase multiphase converter <b>46</b> of <figref idrefs="DRAWINGS">FIG. 6</figref> and makes charging of the battery <b>14</b> possible with three-phase alternating current power in the external charging mode.

p-0098One end of the relay switch SW<b>8</b> is connected to the positive electrode of the battery <b>14</b>. The other end of the relay switch SW<b>8</b> is connected to one end of the inductor L<b>7</b>. The other end of the inductor L<b>7</b> is connected to a connection node between the switching devices SA<b>3</b> and SA<b>4</b>.

p-0099One end of the switching device SA<b>3</b> opposite to the switching device SA<b>4</b> side is connected to a common connection node of the switching devices S<b>1</b>, S<b>3</b>, S<b>5</b>, and S<b>7</b>. One end of the switching device SA<b>4</b> opposite to the switching device SA<b>3</b> side is connected to a common connection node of the switching devices S<b>2</b>, S<b>4</b>, S<b>6</b>, and S<b>8</b>.

p-0100The three-phase power supply plug <b>40</b> is connected to the connection node of the relay switch SW<b>1</b> and the inductor L<b>1</b>, the connection node of the relay switch SW<b>2</b> and the inductor L<b>2</b>, and the connection node of the relay switch SW<b>8</b> and the inductor L<b>7</b>.

p-0101When using IGBTs as the switching devices SA<b>3</b> and SA<b>4</b>, the IGBTs are connected at the connected positions of the switching devices so that the collector terminals are on the upper side in <figref idrefs="DRAWINGS">FIG. 8</figref> and the emitter terminals are on the lower side. Then, between the collector terminal and the emitter terminal of each IGBT is connected a diode so that the anode terminal is on the emitter terminal side.

p-0102An operation of the boost mode will be described. In the boost mode, a controller <b>54</b> controls the relay switches SW<b>1</b> to SW<b>4</b> and SW<b>6</b> to SW<b>8</b> to turn on and SW<b>5</b> to turn off.

p-0103The controller <b>54</b> controls the switching devices S<b>1</b> to S<b>12</b>, SA<b>3</b>, and SA<b>4</b> so that a voltage where the inductor induced electromotive force has been added to the output voltage of the battery <b>14</b> is applied to the front-stage output capacitor <b>18</b>-<b>1</b>, the back-stage output capacitor <b>18</b>-<b>2</b>, and the drive circuit <b>20</b> based on the same control principle with respect to the switching devices connected at the top and bottom in the switching six-phase multiphase converter <b>46</b> of <figref idrefs="DRAWINGS">FIG. 6</figref>. The induced electromotive force generated at each inductor can be adjusted by varying the switching timing of each switching device.

p-0104The controller <b>54</b> adjusts the switching timing of the switching devices in accordance with travel control so that a direct current voltage in accordance with travel control of the mounted vehicle is output from the switching seven-phase multiphase converter <b>52</b> to the drive circuit <b>20</b>.

p-0105This embodiment has a configuration using seven pairs of switching devices connected at the top and bottom. As a result, compared to the case using less than seven pairs of upper and lower switching devices, the ripple component included in the direct current voltage that is output to the drive circuit <b>20</b> can be reduced.

p-0106The drive circuit <b>20</b> performs direct current to alternating current conversion and power transfers between the switching seven-phase multiphase converter <b>52</b> and the drive motor <b>22</b> as well as the power generation motor <b>24</b>.

p-0107Next, an operation in the external charging mode will be described. The controller <b>54</b> controls the relay switches SW<b>1</b> to SW<b>4</b> and SW<b>6</b> to SW<b>8</b> to turn off and SW<b>5</b> to turn on. This results in the circuit configuration shown in <figref idrefs="DRAWINGS">FIG. 9</figref>. The same reference numerals have been applied to parts identical to those shown in <figref idrefs="DRAWINGS">FIG. 8</figref>.

p-0108The three-phase power supply plug <b>40</b> is inserted into a three-phase power supply receptacle. The first electrode of the three-phase power supply plug <b>40</b> is connected to one end of the inductor L<b>1</b> on the relay switch SW<b>1</b> side and the second electrode of the three-phase power supply plug <b>40</b> is connected to one end of the inductor L<b>2</b> on the relay switch SW<b>2</b> side. Furthermore, the third electrode of the three-phase power supply plug <b>40</b> is connected to one end of the inductor L<b>7</b> on the relay switch SW<b>8</b> side.

p-0109A three-phase alternating current voltage is applied from the three-phase power supply plug <b>40</b> via the inductors L<b>1</b>, L<b>2</b>, and L<b>7</b> to the connection node A of the switching devices S<b>1</b> and S<b>2</b>, the connection node B of the switching devices S<b>3</b> and S<b>4</b>, and a connection node H of the switching devices SA<b>3</b> and SA<b>4</b>. The controller <b>54</b> operates the switching devices S<b>1</b> to S<b>4</b>, SA<b>3</b>, and SA<b>4</b> as a three-phase inverter. As a result, interphase voltages mutually between the connection nodes A, B, and H are rectified and boosted so that the resulting direct current voltage is applied to the front-stage output capacitor <b>18</b>-<b>1</b>.

p-0110When the voltages with respect to the neutral point voltage of the first to third electrodes of the three-phase power supply plug <b>40</b> are V sin(ωt), V sin(ωt+120°), and V sin(ωt+240°), respectively, for example, the controller <b>54</b> controls the switching devices S<b>1</b> to S<b>4</b>, SA<b>3</b>, and SA<b>4</b> so that currents flowing into the first to third electrodes are I sin(ωt), I sin(ωt+120°), and I sin(ωt+240°), respectively. As a result, the power factor between electrodes of the three-phase power supply plug <b>40</b> can be set to 1 and the withstand voltage and the withstand current of each part of the switching seven-phase multiphase converter <b>52</b> can be suppressed to necessary minimum values. Furthermore, due to the induced electromotive force of the inductors L<b>1</b>, L<b>2</b>, and L<b>7</b>, a voltage higher than the voltage amplitude between electrodes of the three-phase power supply plug <b>40</b> can be applied to the front-stage output capacitor <b>18</b>-<b>1</b>.

p-0111Similar to the control with respect to the switching six-phase multiphase converter <b>46</b> of <figref idrefs="DRAWINGS">FIG. 7</figref>, the controller <b>54</b> operates the switching devices S<b>5</b> to S<b>8</b> as a single-phase inverter and the switching devices S<b>9</b> to S<b>12</b> as a single-phase inverter. As a result, the switching seven-phase multiphase converter <b>52</b> can obtain the three-phase alternating current voltage from the external power supply device and charge the battery <b>14</b>.

p-0112According to this configuration, the inductors L<b>1</b>, L<b>2</b>, and L<b>7</b>, which are used as boost inductors in the boost mode, can be used as power factor improvement and boost inductors in the external charging mode.

p-0113Furthermore, in the external charging mode, on the basis of the magnetic coupling of the primary-side inductor L<b>3</b>+L<b>4</b> and the secondary-side inductor L<b>5</b>+L<b>6</b> the front-stage section and the back-stage section are coupled and electrically insulated. This makes it possible to avoid an application of a high voltage to the front-stage section, and during the handling of the single-phase power supply plug <b>26</b> in the front-stage section to avoid a shortening of the system life, such as due to contact between parts being applied with high voltages.

p-0114Examples using the switching multiphase converter relating to embodiments of the present invention in hybrid vehicle drive systems were described in the aforementioned. The switching multiphase converter relating to the embodiments of the present invention can be used in electric automobiles. In this case, it is not absolutely necessary to use the power generation motor <b>24</b> and the drive circuit <b>20</b> may have a configuration for direct current to alternating current conversion and power transfers between the switching multiphase converter and the drive motor <b>22</b>.

p-0115Further, among the relay switches employed in the above-described embodiments, those provided in the capacitor discharge path may be additionally provided with a discharge circuit using a resistor.