JP6161002B2 - Power converter - Google Patents

Description

  The present invention relates to a power conversion device.

  In Patent Document 1 below, the voltage applied to the three-phase windings of the switched reluctance motor can be boosted, and the current flowing through the three-phase windings can be regenerated to the capacitive element and the power source. A drive circuit is disclosed. The drive circuit includes one capacitor, nine switching elements, and six diodes. In addition, this drive circuit can also make the rise of the square-wave drive current supplied to the windings for three phases steep.

JP 2012-44816 A

  In the prior art, as described above, the rising of the square-wave drive current supplied to the three-phase windings of the switched reluctance motor can be made steep, but the drive current is generated. For this reason, since it is necessary to use one capacitor, nine switching elements, and six diodes, there is a problem that the number of parts increases.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to reduce the number of circuit components that can make the rising of a square-wave drive current supplied to a switched reluctance motor steep.

  In order to achieve the above object, according to the present invention, as a first solving means, there is provided a power conversion device that includes a switching element, converts power output by a DC power supply, and supplies the power to a coil of a switched reluctance motor. A capacitor having one end connected to the positive side of the DC power source, a first switching element that is the switching element provided between the other end of the capacitor and one end of the coil, and the other end of the coil A second switching element that is the switching element provided between the negative side of the DC power source, a first terminal that is connected to the positive side of the DC power source, and a cathode terminal that is connected to one end of the coil. A diode and an anode terminal are connected to the other end of the coil, and a cathode terminal is connected to the other end of the capacitor. A first operating mode for supplying driving power to the coil from the DC power supply and the capacitor by turning on the first switching element and the second switching element, A second operation mode in which driving power is supplied from the DC power source to the coil by turning on at least the second switching element; turning on the first switching element; and turning off the second switching element. The third operation mode and the fourth operation mode in which power is supplied from the coil to the capacitor by turning off all the switching elements are employed.

  In the present invention, as a second solving means, in the first solving means, a third switching element provided between a positive side of a DC power supply and a cathode terminal of the second diode, and an anode terminal are the DC power supply. And a third diode whose cathode terminal is connected to one end of the coil, respectively, to turn on the third switching element and to turn off the first switching element and the second switching element In the first operation mode, the first switching element and the second switching element are turned on, and a third operation mode is further provided for supplying power from the coil to the DC power supply. Driving power is supplied to the coil from the DC power supply and the capacitor by turning off the switching element. , In the third operation mode, the first switching element to the on state, and to the third switching element in an OFF state in addition to the second switching element, to adopt a means of.

  In the present invention, as a third solving means, further comprising a fourth switching element as the switching element provided between the positive terminal of the DC power source and one end of the capacitor in the second solving means, In the first operation mode, the fourth switching element is also turned on, and in the second operation mode, at least the second switching element and the fourth switching element are turned on, so that the DC power supply is transferred to the coil. Driving power is supplied, and in the third operation mode, the first switching element is turned on, the second switching element and the third switching element are turned off, and the fourth switching element is turned on or off. In the fifth operation mode, the third switching element is turned on. And adopting means that supplies power to the capacitor in addition to the DC power source from the coil by turning off state and the fourth switching element in addition to the first and second switching elements.

  In the present invention, as a fourth solving means, in any one of the first to third solving means, the second switching element and the second diode are provided for a plurality of phases provided in the switched reluctance motor. A means of being provided for each coil is employed.

  According to the present invention, in the first operation mode, the driving power is supplied to the coil of the switched reluctance motor using the DC power supply and the capacitor charged in the fourth operation mode. Can be made steep. Further, according to the present invention, the number of parts can be reduced as compared with the above-described prior art documents.

It is a circuit diagram of the power converter concerning a 1st embodiment of the present invention. It is a timing chart which shows drive current (a), applied voltage (b), and switching (c) of a power converter concerning a 1st embodiment of the present invention. It is a circuit diagram which shows the modification of the power converter device which concerns on 1st Embodiment of this invention. It is a circuit diagram of the power converter device concerning a 2nd embodiment of the present invention. It is a timing chart which shows drive current (a), applied voltage (b), and switching (c) of a power converter concerning a 2nd embodiment of the present invention. It is a timing chart which shows drive current (a), applied voltage (b), and switching (c) of a power converter concerning a 2nd embodiment of the present invention. It is a timing chart which shows drive current (a), applied voltage (b), and switching (c) of a power converter concerning a 2nd embodiment of the present invention. It is a circuit diagram which shows the modification of the power converter device which concerns on 2nd Embodiment of this invention. It is a circuit diagram of the power converter device which concerns on 3rd Embodiment of this invention. It is a timing chart which shows drive current (a), applied voltage (b), and switching (c) of a power converter concerning a 3rd embodiment of the present invention. It is a circuit diagram which shows the modification of the power converter device which concerns on 3rd Embodiment of this invention.

Embodiments of the present invention will be described below with reference to the drawings.
[First embodiment]
First, the first embodiment will be described. The power conversion apparatus according to the first embodiment converts power output from the DC power source E and supplies it to a coil L1 of a switched reluctance motor (not shown). As shown in FIG. 1, such a power conversion device includes a pair of first terminals T1, T2, a pair of second terminals T11, T12, a capacitor C, a first switching element S1, a second switching element S2, It comprises a first diode D1, a second diode D2, and a switch control unit M.

The pair of first terminals T1 and T2 are connected to both ends (plus terminal and minus terminal) of the DC power source E. On the other hand, the pair of second terminals T11 and T12 are connected to both ends of a coil L1 of a switched reluctance motor (not shown).
The capacitor C is provided between the plus side of the DC power source E and one end of the coil L1, and one end is on the plus side of the DC power source E and the other end is on one end of the coil L1 via the first switching element S1. It is connected.

The first switching element S1 is provided between the other end of the capacitor C and one end of the coil L1, and one end is connected to the other end of the capacitor C and the other end is connected to one end of the coil L1.
The second switching element S2 is provided between the other end of the coil L1 and the negative side of the DC power source E, and has one end connected to the other end of the coil L1 and the other end connected to the negative side of the DC power source E. Yes.

  The first switching element S1 and the second switching element S2 are, for example, FET transistors (Field Effect Transistors), the gate terminals of which are connected to the switch control unit M, and the voltage values from the switch control unit M. Is turned on when a control signal having a high level is input to the gate terminal, and is turned off when a control signal having a low voltage value is input to the gate terminal. Further, the first switching element S1 and the second switching element S2 may be, for example, a bipolar transistor or an IGBT (Insulated Gate Bipolar Transistor) in addition to the FET transistor.

The first diode D1 has an anode terminal connected to the positive side of the DC power supply E and a cathode terminal connected to one end of the coil L1.
The second diode D2 has an anode terminal connected to the other end of the coil L1 and a cathode terminal connected to the other end of the capacitor C.

  The switch control unit M is a microcontroller that performs switching control of the first switching element S1 and the second switching element S2, and specifically, the rising and falling timings and duty ratios of the respective gate terminals of the switching elements. Output different control signals.

Next, the operation of the power conversion device configured as described above will be described with reference to FIGS. 1 and 2.
This power converter performs switching of the first switching element S1 and the second switching element S2 and the like in order to supply a square-wave drive current to the coil L1 of the switched reluctance motor (not shown). That is, this power converter performs the 1st-4th operation mode explained below.

  The first operation mode is an operation mode in which driving power is supplied to the coil L1 from the DC power supply E and the capacitor C connected in series. That is, in the first operation mode, the switch control unit M turns on the first switching element S1 and the second switching element S2 (see FIG. 2C). As a result, as shown in FIG. 1A, a current flows through a path from the DC power supply E to the DC power supply E through the capacitor C, the first switching element S1, the coil L1, and the second switching element S2 in this order.

  For example, when the voltage of the DC power source E is EV and the voltage of the capacitor C is CV, the voltage applied to the coil L1 is (EV + CV) (see FIG. 2B). Then, a drive current corresponding to the applied voltage (EV + CV) is supplied to the coil L1. As a result, the drive current increases rapidly (see FIG. 2A). Then, when all the electric charge stored in the capacitor C is discharged, the first operation mode ends and the operation mode shifts to the second operation mode.

  The second operation mode is an operation mode in which driving power is supplied from only the DC power source E to the coil L1 after the end of the first operation mode. In FIG. 2C, in the second operation mode, the first switching element S1 is in the on state. However, the first switching element S1 may be in the on state or in the off state. .

  In the second operation mode, as shown in FIG. 1B, a current flows through a path from the DC power supply E to the DC power supply E through the first diode D1, the coil L1, and the second switching element S2 in this order. As a result, the drive current rises following the first operation mode (see FIG. 2A). Then, the switch control unit M turns on the first switching element S1 and turns off the second switching element S2, thereby ending the second operation mode and shifting to the third operation mode (see FIG. 2 (c)).

  The third operation mode is an operation mode for returning the electric power generated from the coil L1. That is, the third operation mode is an operation mode in which the electric power generated from the coil L1 is recirculated and consumed as heat. As described above, in the third operation mode, the switch control unit M turns on the first switching element S1 and turns off the second switching element S2 (see FIG. 2C). As a result, as shown in FIG. 1C, a current flows through a path from the coil L1 to the coil L1 through the second diode D2 and the first switching element S1 in this order. As a result, the electric power generated from the coil L1 is consumed as heat.

  Thereafter, the switch control unit M repeats switching between the second operation mode and the third operation mode by switching between the ON state and the OFF state of the second switching element S2. As a result, the drive current rises and falls near the target current value Ref (see FIG. 2A). That is, the drive current is controlled to be stable in the vicinity of the target current value Ref.

  Then, the switch control unit M shifts to the fourth operation mode by turning off the first switching element S1 and the second switching element S2 (see FIG. 2C).

  The fourth operation mode is an operation mode in which electric power generated from the coil L1 is supplied to the capacitor C for charging. As described above, in the fourth operation mode, the switch control unit M turns off both the first switching element S1 and the second switching element S2 (see FIG. 2C).

  As a result, as shown in FIG. 1 (4), a current flows along a path from the coil L1 to the coil L1 through the second diode D2, the capacitor C, and the first diode D1 in this order. As a result, charges are stored in the capacitor C. Along with this, the drive current supplied to the coil L1 decreases (see FIG. 2A). The power converter continuously generates the square-wave drive current by repeating the first to fourth operation modes, and supplies it to the coil L1 of the switched reluctance motor (not shown).

Subsequently, a modified example of the first embodiment will be described.
In the modification of the first embodiment, drive currents having phases different by 120 degrees are supplied to coils L1, L2, and L3 for three phases of a switched reluctance motor (not shown). As shown in FIG. 3, the modification of the first embodiment includes three pairs of second terminals T11, T12, T21, T22, T31, T32, second switching elements S2, S12, S22, and a second diode D2. It differs from the first embodiment described above in that D12 and D22 are provided for each of the coils L1, L2, and L3 provided in the switched reluctance motor.

  Other components are the same as those in the first embodiment. The pair of first terminals T1, T2, the capacitor C, the first switching element S1, and the first diode D1 are used to generate driving currents that are shared and supplied to the coils L1, L2, and L3, respectively. . Therefore, description of components similar to those of the first embodiment described above in the modification of the first embodiment is omitted.

The pair of second terminals T21 and T22 are connected to both ends of a coil L2 of a switched reluctance motor (not shown).
The second switching element S12 is provided between the other end of the coil L2 and the negative side of the DC power source E, and has one end connected to the other end of the coil L2 and the other end connected to the negative side of the DC power source E. Yes.
The second diode D12 has an anode terminal connected to the other end of the coil L2, and a cathode terminal connected to the other end of the capacitor C.

The pair of second terminals T31 and T32 are connected to both ends of a coil L3 of a switched reluctance motor (not shown).
The second switching element S22 is provided between the other end of the coil L3 and the negative side of the DC power source E, and has one end connected to the other end of the coil L3 and the other end connected to the negative side of the DC power source E. Yes.

The second diode D22 has an anode terminal connected to the other end of the coil L3 and a cathode terminal connected to the other end of the capacitor C.
The second switching elements S12 and S22 may be, for example, FET transistors, bipolar transistors, or IGBTs, similarly to the first switching element S1 and the second switching element S2. The switch control unit M also controls the second switching elements S12 and S22 in addition to the first switching element S1 and the second switching element S2.

  The modification of the first embodiment configured as described above is the first to the first embodiment described above for generating a square-wave drive current to be supplied to each of the coils L1, L2, and L3 of the switched reluctance motor. The fourth operation mode is executed, and square-wave drive currents having different phases by 120 degrees are supplied to the coils L1, L2, and L3.

  Here, the square portions of the drive currents having different phases by 120 degrees (between rising and falling) are controlled so as not to overlap with each other. That is, the first terminals T1 and T2, the capacitor C, the first switching element S1, and the first diode D1 that are shared for generating each driving current are used for generating each driving current at different times.

  According to the present embodiment, in the first operation mode, the coil L1 (or the coils L2, L3) of the switched reluctance motor is used by using the DC power source E and the capacitor C charged in the fourth operation mode. Since the drive current is supplied, the rising of the square-wave drive current can be made steep. Further, according to the present embodiment, the number of parts can be reduced as compared with the above-described prior art documents.

[Second Embodiment]
Next, a power conversion device according to the second embodiment will be described.
As shown in FIG. 4, the power converter according to the second embodiment is different from the first embodiment in that it includes a third switching element S3 and a third diode D3. Other components are the same as those in the first embodiment. Therefore, in the second embodiment, the description of the same components as in the first embodiment is omitted.

The third switching element S3 is provided between the positive side of the DC power supply E and the cathode terminal of the second diode D2, one end being the positive side of the DC power supply E and the other end being the cathode terminal of the second diode D2. Each is connected. The third switching element S3 may be, for example, an FET transistor, a bipolar transistor, or an IGBT, like the first switching element S1 and the second switching element S2.
The third diode D3 has an anode terminal connected to the negative side of the DC power source E and a cathode terminal connected to one end of the coil L1.

Next, the operation of the second embodiment configured as described above will be described with reference to FIGS.
The first operation mode is an operation mode in which driving power is supplied to the coil L1 from the DC power supply E and the capacitor C connected in series as in the first embodiment. That is, in the first operation mode of the second embodiment, the switch control unit M turns on the first switching element S1 and the second switching element S2, and turns off the third switching element (FIG. 5C). )reference).

  As a result, as shown in FIG. 4A, as in the first embodiment, the DC power source E is changed from the DC power source E through the capacitor C, the first switching element S1, the coil L1, and the second switching element S2 in order. Current flows through the route. For example, when the voltage of the DC power source E is EV and the voltage of the capacitor C is CV, the voltage applied to the coil L1 is (EV + CV) (see FIG. 5B).

  Then, a drive current corresponding to the applied voltage (EV + CV) is supplied to the coil L1. As a result, the drive current increases rapidly (see FIG. 5A). Then, when all the electric charge stored in the capacitor C is discharged, the first operation mode ends and the operation mode shifts to the second operation mode.

  Similar to the first embodiment, the second operation mode is an operation mode in which driving power is supplied from only the DC power source E to the coil L1 after the end of the first operation mode. In FIG. 5C, in the second operation mode, the first switching element S1 is in an on state, but the first switching element S1 may be in an on state or an off state. .

  In the second operation mode, as shown in FIG. 4B, a current flows through a path from the DC power supply E to the DC power supply E through the first diode D1, the coil L1, and the second switching element S2 in this order. Further, when the first switching element S1 is in the on state, the direct-current power source E causes the direct current through the antiparallel diode of the third switching element S3, the first switching element S1, the coil L1, and the second switching element S2 in order. Current also flows in the path to the power supply E. As a result, the drive current rises following the first operation mode (see FIG. 5A).

  Then, the switch control unit M ends the second operation mode by turning on the first switching element S1 and turning off the second switching element S2 and the third switching element S3, and performs the third operation. The mode is changed (see FIG. 5C).

  The third operation mode is an operation mode in which power generated from the coil L1 is returned as in the first embodiment. That is, the third operation mode is an operation mode in which the electric power generated from the coil L1 is recirculated and consumed as heat. As described above, in the third operation mode, the switch control unit M turns on the first switching element S1 and turns off the second switching element S2 and the third switching element S3 (FIG. 5C). reference). As a result, as shown in FIG. 4 (3), a current flows through a path from the coil L1 to the coil L1 through the second diode D2 and the first switching element S1 in this order. As a result, the electric power generated from the coil L1 is consumed as heat.

  Thereafter, the switch control unit M controls the first switching element S1, the second switching element S2, and the third switching element S3 to repeat switching between the second operation mode and the third operation mode. As a result, the drive current rises and falls near the target current value Ref (see FIG. 5A). That is, the drive current is controlled to be stable in the vicinity of the target current value Ref.

  Then, the switch control unit M shifts to the fourth operation mode by turning off the first switching element S1, the second switching element S2, and the third switching element S3 (see FIG. 5C).

  As in the first embodiment, the fourth operation mode is an operation mode in which the electric power generated from the coil L1 is supplied to the capacitor C to be charged. As described above, in the fourth operation mode, the switch control unit M turns off the first switching element S1, the second switching element S2, and the third switching element S3 (see FIG. 5C).

  As a result, as shown in FIG. 4 (4), a current flows along a path from the coil L1 to the coil L1 through the second diode D2, the capacitor C, and the first diode D1 in this order. As a result, charges are stored in the capacitor C. Along with this, the drive current supplied to the coil L1 decreases (see FIG. 5A).

  On the other hand, in the present embodiment, the switch control unit M changes to the fourth operation mode by turning on the third switching element S3 and turning off the first switching element S1 and the second switching element S2. Then, the mode may be shifted to the fifth operation mode (see FIG. 6C).

  The fifth operation mode is an operation mode in which the electric power generated from the coil L1 is supplied to the DC power source E. As described above, in the fifth operation mode, the switch control unit M turns on the third switching element S3 and turns off the first switching element S1 and the second switching element S2 (FIG. 6C). reference). As a result, as shown in FIG. 4 (5), a current flows from the coil L1 through the second diode D2, the third switching element S3, the DC power source E, and the third diode D3 in this order to the coil L1. As a result, electric power is supplied to the DC power source E. Along with this, the drive current supplied to the coil L1 decreases (see FIG. 6A).

  The power conversion apparatus may continuously generate a square-wave drive current by repeating the first to fourth operation modes and supply it to the coil L1 of the switched reluctance motor (not shown) (see FIG. 5). Further, the fifth operation mode may be executed instead of the fourth operation mode. When the fifth operation mode is executed, no electric charge is stored in the capacitor C, so that the second operation mode is executed instead of the first operation mode (see FIG. 6). Further, as shown in FIG. 7, after the transition to the fourth operation mode, the transition from the fourth operation mode to the fifth operation mode may be performed after a specific time has elapsed.

Subsequently, a modification of the second embodiment will be described.
In the modification of the second embodiment, drive currents having phases different by 120 degrees are supplied to the coils L1, L2, and L3 for three phases of a switched reluctance motor (not shown). As shown in FIG. 8, the modification of the second embodiment includes three pairs of second terminals T11, T12, T21, T22, T31, T32, second switching elements S2, S12, S22, and a second diode D2. It differs from the second embodiment described above in that D12 and D22 are provided for each of the coils L1, L2, and L3 provided in the switched reluctance motor.

  Other components are the same as those in the second embodiment. The pair of first terminals T1, T2, the capacitor C, the first switching element S1, the first diode D1, the third switching element S3, and the third diode D3 are shared and used for generating each drive current. . That is, the modification of the second embodiment is obtained by adding the third switching element S3 and the third diode D3 to the modification of the first embodiment. Therefore, description of each component of the modified example of the second embodiment is omitted.

  The modification of the second embodiment configured as described above is the first to the second embodiments described above for generating a square-wave drive current to be supplied to each of the coils L1, L2, and L3 of the switched reluctance motor. The fourth operation mode is executed, and square-wave drive currents having different phases by 120 degrees are supplied to the coils L1, L2, and L3. In the modification of the second embodiment, the fifth operation mode may be executed instead of the fourth operation mode. When the fifth operation mode is executed, no electric charge is stored in the capacitor C, so that the second operation mode is executed instead of the first operation mode (see FIG. 6). Further, as shown in FIG. 7, after the transition to the fourth operation mode, the transition from the fourth operation mode to the fifth operation mode may be performed after a specific time has elapsed.

  Here, as in the modification of the first embodiment, the square portions of the drive currents having different phases by 120 degrees (between rising and falling) are controlled so as not to overlap with each other. That is, the first terminals T1 and T2, the capacitor C, the first switching element S1, the first diode D1, the third switching element S3, and the third diode D3 that are shared for generating each driving current are shifted in time, Used to generate drive current.

  According to the present embodiment, in the first operation mode, the coil L1 (or the coils L2, L3) of the switched reluctance motor is used by using the DC power source E and the capacitor C charged in the fourth operation mode. Since the drive current is supplied, the rising of the square-wave drive current can be made steep. Further, according to the present embodiment, the number of parts can be reduced as compared with the above-described prior art documents. Also. According to the present embodiment, power is supplied from the coil L1 (or coils L2, L3) to the DC power source E in the fifth operation mode, so that power consumption can be reduced.

[Third Embodiment]
Next, the power converter device which concerns on 3rd Embodiment is demonstrated with reference to FIG.9 and FIG.10.
As shown in FIG. 9, the power converter according to the third embodiment is different from the second embodiment in that it includes a fourth switching element S4. Other components are the same as those in the second embodiment. Therefore, in the third embodiment, description of the same components as those in the second embodiment is omitted.

  The fourth switching element S4 is provided between the plus side of the DC power supply E and one end of the capacitor C, and one end is connected to the plus terminal of the DC power supply E and the other end is connected to one end of the capacitor C.

Next, the operation of the third embodiment configured as described above will be described with reference to FIGS.
As in the second embodiment, the first operation mode is an operation mode in which driving power is supplied from the DC power supply E and the capacitor C connected in series to the coil L1. That is, in the first operation mode of the third embodiment, the switch control unit M turns on the first switching element S1, the second switching element S2, and the fourth switching element S4 and turns off the third switching element. To do.

  As a result, as shown in FIG. 9 (1), the DC power supply E reaches the DC power supply E through the fourth switching element S4, the capacitor C, the first switching element S1, the coil L1, and the second switching element S2 in order. Current flows through the path. For example, when the voltage of the DC power source E is EV and the voltage of the capacitor C is CV, the voltage applied to the coil L1 is (EV + CV) (see FIG. 10B).

  Then, a drive current corresponding to the applied voltage (EV + CV) is supplied to the coil L1. As a result, the drive current increases rapidly (see FIG. 10A). Then, when all the electric charge stored in the capacitor C is discharged, the first operation mode ends and the operation mode shifts to the second operation mode.

  Similar to the second embodiment, the second operation mode is an operation mode in which driving power is supplied from only the DC power source E to the coil L1 after the end of the first operation mode. In FIG. 10C, in the second operation mode, the first switching element S1 is in an on state, but the first switching element S1 may be in an on state or an off state. .

  In the second operation mode, as shown in FIG. 9B, a path from the DC power supply E to the DC power supply E through the fourth switching element S4, the first diode D1, the coil L1, and the second switching element S2 in this order. Current flows. Further, when the first switching element S1 is in the on state, the direct-current power source E causes the direct current through the antiparallel diode of the third switching element S3, the first switching element S1, the coil L1, and the second switching element S2 in order. Current also flows in the path to the power supply E. As a result, the drive current increases following the first operation mode (see FIG. 5A).

  Then, the switch control unit M ends the second operation mode by turning on the first switching element S1 and turning off the second switching element S2 and the third switching element S3, and performs the third operation. The mode is changed (see FIG. 10C). In FIG. 10C, in the third operation mode, the fourth switching element S4 is in the on state, but the fourth switching element S4 may be in the on state or in the off state. .

  The third operation mode is an operation mode in which the electric power generated from the coil L1 is returned as in the second embodiment. That is, the third operation mode is an operation mode in which the electric power generated from the coil L1 is recirculated and consumed as heat. As described above, in the third operation mode, the switch control unit M turns on the first switching element S1 and turns off the second switching element S2 and the third switching element S3 (FIG. 10C). reference). In addition, about 4th switching element S4, as shown to FIG.10 (c), an ON state may be sufficient and an OFF state may be sufficient. As a result, as shown in FIG. 9 (3), a current flows through a path from the coil L1 to the coil L1 through the second diode D2 and the first switching element S1 in this order. As a result, the electric power generated from the coil L1 is consumed as heat.

  Thereafter, the switch control unit M controls the first switching element S1, the second switching element S2, the third switching element S3, and the fourth switching element S4, and repeatedly switches between the second operation mode and the third operation mode. . As a result, the drive current rises and falls near the target current value Ref (see FIG. 10A). That is, the drive current is controlled to be stable in the vicinity of the target current value Ref.

  Then, the switch control unit M shifts to the fourth operation mode by turning off the first switching element S1, the second switching element S2, the third switching element S3, and the fourth switching element S4.

  As in the second embodiment, the fourth operation mode is an operation mode in which power generated from the coil L1 is supplied to the capacitor C to be charged. As described above, in the fourth operation mode, the switch control unit M turns off the first switching element S1, the second switching element S2, the third switching element S3, and the fourth switching element S4.

  As a result, as shown in FIG. 9 (4), a current flows along a path from the coil L1 to the coil L1 through the second diode D2, the capacitor C, and the first diode D1 in this order. As a result, charges are stored in the capacitor C. Along with this, the drive current supplied to the coil L1 decreases.

  On the other hand, in the present embodiment, the switch control unit M turns on the third switching element S3 and turns off the first switching element S1, the second switching element S2, and the third switching element S3. Instead of the fourth operation mode, a transition may be made to the fifth operation mode (see FIG. 10C).

  The fifth operation mode is an operation mode in which the electric power generated from the coil L1 is supplied to the DC power source E. As described above, in the fifth operation mode, the switch control unit M turns on the third switching element S3 and turns off the first switching element S1, the second switching element S2, and the fourth switching element S4. (See FIG. 10 (c)). As a result, as shown in FIG. 9 (5), a current flows from the coil L1 through the second diode D2, the third switching element S3, the DC power supply E, and the third diode D3 in this order to the coil L1. Further, as shown in FIG. 9 (5), a current flows through a path from the coil L1 to the coil L1 through the second diode D2, the capacitor C, and the first diode D1 in this order. Along with this, the drive current supplied to the coil L1 decreases (see FIG. 10A).

  The power converter may continuously generate a square-wave drive current by repeating the first to fourth operation modes and supply the drive current to the coil L1 of the switched reluctance motor (not shown). Instead of the fourth operation mode, the first to third and fifth operation modes may be repeated (see FIG. 10).

Subsequently, a modification of the third embodiment will be described.
In the modification of the third embodiment, drive currents having phases different by 120 degrees are supplied to coils L1, L2, and L3 for three phases of a switched reluctance motor (not shown). As shown in FIG. 11, the modification of the third embodiment includes three pairs of second terminals T11, T12, T21, T22, T31, T32, second switching elements S2, S12, S22 and a second diode D2. It differs from the third embodiment described above in that D12 and D22 are provided for each of the coils L1, L2 and L3 provided in the switched reluctance motor.

  Other components are the same as those in the third embodiment. The pair of first terminals T1, T2, capacitor C, first switching element S1, first diode D1, third switching element S3, third diode D3, and fourth switching element S4 are shared and driven. Used to generate current. That is, the modification of the third embodiment is obtained by adding the fourth switching element S4 to the modification of the second embodiment. Therefore, description of each component of the modification of the third embodiment is omitted.

  The modification of the third embodiment configured as described above is the first to third embodiments described above for generating the square-wave drive current supplied to each of the coils L1, L2, and L3 of the switched reluctance motor. The fourth operation mode is executed, and square-wave drive currents having different phases by 120 degrees are supplied to the coils L1, L2, and L3. Further, in the modification of the second embodiment, the first to third and fifth operation modes may be executed instead of the fourth operation mode (see FIG. 10).

  Here, the rectangular portions (between rising and falling) of the driving current having phases different by 120 degrees are controlled so as not to overlap with each other as in the modification of the first embodiment. That is, the first terminals T1 and T2, the capacitor C, the first switching element S1, the first diode D1 and the third switching element S3, the third diode D3 and the fourth switching element S4, which are shared for generating each drive current, It is used to generate each drive current at different times.

  According to this embodiment, in the first operation mode, the DC power source E and the capacitor L1 (or coil) of the switched reluctance motor using the capacitor C charged in the fourth operation mode or the fifth operation mode. Since the drive current is supplied to L2, L3), the rising of the square-wave drive current can be made steep. Further, according to the present embodiment, the number of parts can be reduced as compared with the above-described prior art documents. Also. According to the present embodiment, power is supplied from the coil L1 (or coils L2, L3) to the DC power source E in the fifth operation mode, so that power consumption can be reduced. Further, since the charging voltage of the capacitor C can be limited to the DC power source E, it is possible to prevent the capacitor C from being overcharged.

As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment, For example, the following modifications can be considered.
In the first to third embodiments, the present invention is applied to a power conversion device for converting electric power from a DC power source and supplying it to a three-phase switched reluctance motor. You may make it apply this invention to the power converter device for converting electric power and supplying electric power to multiphase switched reluctance motors other than three phases.

  C ... capacitor, D1 ... first diode, D12 ... second diode, D2 ... second diode, D22 ... second diode, D3 ... third diode, E ... DC power supply, L1 ... coil, L2 ... coil, L3 ... coil , M ... switch control unit, S1 ... first switching element, S12 ... second switching element, S2 ... second switching element, S22 ... second switching element, S3 ... third switching element, S4 ... fourth switching element, T1 ... 1st terminal, T2 ... 1st terminal, T11 ... 2nd terminal, T12 ... 2nd terminal, T21 ... 2nd terminal, T22 ... 2nd terminal, T31 ... 2nd terminal, T32 ... 2nd terminal

Claims (4)

A power conversion device that includes a switching element, converts power output by a DC power supply, and supplies the converted power to a coil of a switched reluctance motor,
A capacitor having one end connected to the positive side of the DC power supply;
A first switching element that is the switching element provided between the other end of the capacitor and one end of the coil;
A second switching element that is the switching element provided between the other end of the coil and the negative side of the DC power source;
A first diode having an anode terminal connected to the positive side of the DC power supply and a cathode terminal connected to one end of the coil;
A second diode having an anode terminal connected to the other end of the coil and a cathode terminal connected to the other end of the capacitor;
A first operation mode in which driving power is supplied from the DC power supply and the capacitor to the coil by turning on the first switching element and the second switching element, and at least the second switching element is turned on. A second operation mode for supplying driving power from the DC power source to the coil, a third operation mode for turning on the first switching element and turning off the second switching element, and all the switching elements. And a fourth operation mode in which power is supplied from the coil to the capacitor by turning off the power. A third switching element provided between the positive side of the DC power supply and the cathode terminal of the second diode;
A third diode having an anode terminal connected to the negative side of the DC power source and a cathode terminal connected to one end of the coil;
A fifth operation mode for supplying power from the coil to the DC power source by turning on the third switching element and turning off the first switching element and the second switching element;
In the first operation mode, the first switching element and the second switching element are turned on and the third switching element is turned off to supply driving power to the coil from the DC power supply and the capacitor. ,
2. The power conversion device according to claim 1, wherein in the third operation mode, the first switching element is turned on, and the third switching element is turned off in addition to the second switching element. A fourth switching element that is the switching element provided between the positive terminal of the DC power supply and one end of the capacitor;
In the first operation mode, the fourth switching element is also turned on,
In the second operation mode, at least the second switching element and the fourth switching element are turned on to supply driving power from the DC power source to the coil,
In the third operation mode, the first switching element is turned on, the second switching element and the third switching element are turned off, and the fourth switching element is turned on or off,
In the fifth operation mode, the third switching element is turned on, and the fourth switching element is turned off in addition to the first switching element and the second switching element, so that the coil and the DC power supply are added. The power converter according to claim 2, wherein power is supplied to the capacitor.   4. The electric power according to claim 1, wherein the second switching element and the second diode are provided for each of a plurality of coils provided in the switched reluctance motor. 5. Conversion device.

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