JP6892595B2 - Switched reluctance motor unit and control method of switched reluctance motor unit - Google Patents

Description

The present invention relates to a switched reluctance motor unit including a switched reluctance motor in which a plurality of phases of coils are connected in series.

A switched reluctance motor unit including a switched reluctance motor having a simple motor structure and a motor control device for driving the switched reluctance motor is known.

As the motor control device, for example, Patent Document 1 has a pair of series circuits including a switching element and a diode, and corresponds to the middle point of one series circuit corresponding to each phase and the other one phase. An inverter device including an inverter circuit formed by connecting a midpoint to the other series circuit with a pressure equalizing wire is disclosed.

In the inverter device disclosed in Patent Document 1, when a current flows through a coil of one phase and a current flows through a coil of another phase, the current flows through the coil of the one phase. A configuration is disclosed in which an extra current is suppressed from flowing through the coil by commutating the coil.

Japanese Unexamined Patent Publication No. 2000-295891

By the way, when the current flowing through the coil of one phase is commutated as in the inverter device disclosed in Patent Document 1 described above, the current flowing through the coil of the one phase is sharply reduced and the switch is switched. The output torque of the reluctance motor decreases.

An object of the present invention is that in a switched reluctance motor unit including a switchd reluctance motor and a motor control device, a current flowing through the coil of one phase is compared with a current flowing through a coil of one phase. The purpose is to realize a configuration that can suppress the decrease of.

The switched reluctance motor unit according to an embodiment of the present invention is said to be described by supplying an electric current to a switched reluctance motor having a plurality of phases of coils connected in series and the coils of the plurality of phases. It includes a motor control device that controls the drive of the switched reluctance motor. The motor control device includes a switching circuit in which a plurality of switching arms configured by connecting a pair of switching elements in series are connected in parallel, and a switching control unit that controls driving of the switching elements. The midpoint of the pair of switching elements in the plurality of switching arms is both ends of a series circuit formed by connecting the coils of the plurality of phases in series, and the coils of the plurality of phases in the series circuit. One point is connected to each other's midpoint. The pair of switching elements form an upper arm and a lower arm of the switching arm, respectively. The switching control unit sets each of the switching elements of the upper arm and the lower arm so that a current flows from the high potential side to the low potential side to the coil of one phase of the coils of the plurality of phases. The upper arm and the lower arm are turned on, and after the supply state, the upper arm and the lower arm are brought into a reflux state in which the current continues to flow in the direction in which the current flows to the coil of the one phase in the supply state. Only one switching element is turned on (first configuration).

With the above configuration, the number of switching elements required according to the number of both ends of the series circuit formed by connecting the coils of a plurality of phases in series and the number of midpoints between the coils in the series circuit. Is decided. For example, when the switched reluctance motor has a three-phase coil, the number of switching elements required is eight, and the number of elements can be reduced as compared with the conventional configuration. Therefore, a compact switched reluctance motor unit with low manufacturing cost can be obtained.

Then, as described above, after the supply state in which the current flows from the high potential side to the low potential side in the coil of one phase among the coils of the plurality of phases, the coil of the one phase is supplied in the supply state. By setting the reflux state in which the current continues to flow in the direction in which the current flows, the current flowing through the coil is not sharply reduced as compared with the case where the current flowing through the coil is commutated as in the conventional configuration. As a result, it is possible to suppress a decrease in torque of the switched reluctance motor as compared with the conventional configuration. That is, the output torque of the switched reluctance motor can be increased as compared with the conventional configuration.

In the first configuration, the switching control unit drives the pair of switching elements in the plurality of switching arms from the high potential side with respect to the coil of one phase of the coils of the plurality of phases. When switching from the first supply state in which the current flows to the low potential side to the second supply state in which the current flows from the high potential side to the low potential side with respect to the coils of the other phases, and switching to the second supply state. , The switching element is driven so as to be in the recirculation state in which the current recirculates to the coil of the one phase (second configuration).

In a switched reluctance motor in which coils of a plurality of phases are connected in series, a current flows through the coils of each phase in order. In such a switched reluctance motor, if the voltages generated at both ends of the coils of each phase are not equal at the midpoints of the coils, the current may flow to a coil different from the coil to which the current originally wants to flow. Specifically, when a current flows through a coil of one phase and a current flows through a coil of another phase, that is, when a current flows through a coil of two phases at the same time, a potential difference occurs at the midpoint of the coils of each phase. This can result in current flowing through the coils of each phase in unintended directions.

On the other hand, as described above, from the first supply state in which the current flows from the high potential side to the low potential side for the coils of one phase, the low potential from the high potential side to the coils of the other phase. When switching to the second supply state in which the current flows to the side, the potential difference is reached at the midpoint of the coils of each phase connected in series by passing the current so as to be in a reflux state with respect to the coil of the one phase. Can be prevented from occurring.

Moreover, as in the above configuration, by passing a current through the coil of the one phase so as to be in a reflux state, the coil has a current as compared with the case where the current flowing through the coil is commutated as in the conventional configuration. The flowing current does not drop sharply. As a result, it is possible to suppress a decrease in torque of the switched reluctance motor as compared with the conventional configuration. That is, the output torque of the switched reluctance motor can be increased as compared with the conventional configuration.

In the second configuration, when the switching control unit switches from the first supply state to the second supply state, the switching control unit is in the recirculation state in which the current recirculates to the coil of the one phase. Among the upper arm and the lower arm, the switching element of the same arm as the switching element that is in the on state in the first supply state is turned on (third configuration).

In the above configuration, the same arm as the switching element that is turned on in the first supply state among the upper arm and the lower arm of the switching arm when the current is returned to the coil of the one phase in the reflux state. By turning on the switching element of, the number of switching elements to be driven can be reduced. Therefore, the switching loss can be reduced, and the direction in which the current flows can be smoothly switched by driving the switching element.

In the second or third configuration, the switching control unit returns the current to the coil of at least one phase of the plurality of phases of the coil in the reflux state, and the upper arm and the lower arm. Among the arms, the switching element of the arm other than the arm that turns on the switching element when the current is recirculated to the coils of the other phase in the recirculating state is turned on (fourth configuration).

When only the switching element of the same arm of the upper arm and the lower arm of the switching arm is driven when the current is recirculated to the coil of each phase in the recirculated state, the current is recirculated to the coil of a certain phase. When a current is passed through the other phases while circulating the current, a potential difference occurs at the midpoint of the coil of each phase. Therefore, when the current is refluxed to the coil of the one phase in the reflux state, the arm is different from the arm that drives the switching element when the current is refluxed to the coil of the other phase in the reflux state. Drives the switching element of. This makes it possible to prevent a potential difference from occurring at the midpoint of the coils of each phase connected in series.

The control method of the switch reluctance motor unit according to the embodiment of the present invention is configured by connecting a switch reluctance motor having a plurality of phases of coils connected in series and a pair of switching elements in series. A plurality of switching arms are connected in parallel, and the midpoint of the pair of switching elements is formed at both ends of a series circuit formed by connecting the coils of the plurality of phases in series, and in the series circuit. This is a control method of a switch reluctance motor unit including a switching circuit in which one point is connected to each of the midpoints of the coils of the plurality of phases.

In this control method, by driving the pair of switching elements in the plurality of switching arms, a current flows from the high potential side to the low potential side with respect to the coil of one phase of the coils of the plurality of phases. In one supply state, the supply state detection step of detecting the second supply state in which a current flows from the high potential side to the low potential side with respect to the coils of the other phases, and the above one when the second supply state is detected. In the first supply state of the upper arm and the lower arm respectively composed of the pair of switching elements in the plurality of switching arms so that the current flows back to the coils of one phase. It has a recirculation step of turning on the switching element of the same arm as the switching element in the on state (first method).

According to the switched reluctance motor unit according to the embodiment of the present invention, the midpoint of the pair of switching elements in the plurality of switching arms is a series circuit formed by connecting the coils of a plurality of phases in series. One point is connected to both ends and the middle point of the plurality of phases of the coils in the series circuit.

Then, the switching control unit that controls the drive of the switching element has an upper arm and an upper arm so that a current flows from the high potential side to the low potential side to the coil of one of the plurality of phases. Each switching element of the lower arm is turned on, and after the supply state, the current flows in the direction in which the current flows through the coil of the one phase in the supply state. Turn on the switching element of only one of the upper arm and the lower arm.

As a result, in the switched reluctance motor unit provided with the switched reluctance motor and the motor control device, the current flowing through the coil of one phase is reduced as compared with the case where the current flowing through the coil of one phase is commutated. Suppress.

FIG. 1 is a control block diagram showing a schematic configuration of a switched reluctance motor unit according to an embodiment. FIG. 2 is a diagram schematically showing a current flow in the supply mode. FIG. 3 is a diagram schematically showing the current flow in the regenerative mode. FIG. 4 is a diagram schematically showing the current flow in the reflux mode. FIG. 5 shows an example of the operation mode and switching operation in each phase when the timings of the currents flowing through the coils of each phase do not overlap. FIG. 6 is a flow showing the operation of setting the operation mode for each phase. FIG. 7 is a diagram schematically showing the current flow in the case of the reflux mode in the current control of the pattern 2. FIG. 8 shows an example of the operation mode and switching operation in each phase when the timings of the currents flowing through the coils of each phase overlap. FIG. 9 is a diagram for explaining the effect of the embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The same or corresponding parts in the drawings are designated by the same reference numerals, and the description thereof will not be repeated.

FIG. 1 is a block diagram showing a schematic configuration of a switched reluctance motor unit 1 according to an embodiment of the present invention. The switched reluctance motor unit 1 includes a switched reluctance motor 2 and a motor control device 3 having a switching circuit 4 for driving the switched reluctance motor 2. The motor control device 3 controls the drive of the switched reluctance motor 2 by the switching circuit 4.

The switched reluctance motor 2 includes a rotor (not shown) and a stator 10 having three-phase coils 11, 12, and 13. The stator 10 has an A-phase coil 11, a B-phase coil 12, and a C-phase coil 13. The A-phase coil 11, the B-phase coil 12, and the C-phase coil 13 are connected in series. Specifically, the A-phase coil 11 and the C-phase coil 13 are connected in series to both ends of the B-phase coil 12. By connecting the A-phase coil 11, the B-phase coil 12, and the C-phase coil 13 in series in this way, the series circuit 10a is configured. Since the configuration of the switched reluctance motor 2 is the same as the configuration of a general switched reluctance motor, detailed description thereof will be omitted.

In FIG. 1, reference numeral 6 is a current detection unit for detecting the current flowing through the coils 11, 12, and 13 of each phase of the switched reluctance motor 2. The current value data detected by the current detection unit 6 is input to the switching control unit 5 described later of the motor control device 3.

The motor control device 3 includes a switching circuit 4, a DC power supply 31, a capacitor 32, and a switching control unit 5.

The switching circuit 4 is a switching circuit including a plurality of switching elements SW1 to SW8 constituting a bridge circuit so as to drive the switched reluctance motor 2. The switching circuit 4 is connected in parallel to the DC power supply 31 and the capacitor 32. The DC power supply 31 and the capacitor 32 are connected in parallel.

The switching elements SW1 and SW2 are connected in series to form a first switching arm 41 as a switching arm. The switching elements SW3 and SW4 are connected in series to form a second switching arm 42 as a switching arm. The switching elements SW5 and SW6 are connected in series to form a third switching arm 43 as a switching arm. The switching elements SW7 and SW8 are connected in series to form a fourth switching arm 44 as a switching arm.

That is, the switching circuit 4 has a plurality of switching arms. The first switching arm 41, the second switching arm 42, the third switching arm 43, and the fourth switching arm 44 constituting the plurality of switching arms are each composed of a pair of switching elements connected in series.

The first switching arm 41, the second switching arm 42, the third switching arm 43, and the fourth switching arm 44 are connected in parallel to the DC power supply 31 and the capacitor 32, respectively.

In the first switching arm 41, the second switching arm 42, the third switching arm 43, and the fourth switching arm 44, the switching elements SW1, SW3, SW5, and SW7 form the upper arm 4a of each arm, and the switching elements SW2, SW4, SW6, and SW8 form a lower arm 4b of each arm.

In the first switching arm 41, the midpoint of the switching elements SW1 and SW2 is connected to one end of the A-phase coil 11 in the switched reluctance motor 2, that is, one end of the series circuit 10a. In the second switching arm 42, the midpoint of the switching elements SW3 and SW4 is connected to the midpoint (connection point) between the A-phase coil 11 and the B-phase coil 12 in the switched reluctance motor 2. In the third switching arm 43, the midpoint of the switching elements SW5 and SW6 is connected to the midpoint (connection point) between the B-phase coil 12 and the C-phase coil 13 in the switched reluctance motor 2. In the fourth switching arm 44, the midpoints of the switching elements SW7 and SW8 are connected to one end of the C-phase coil 13 in the switched reluctance motor 2, that is, the other end of the series circuit 10a.

As described above, the midpoints of the pair of switching elements in the first switching arm 41, the second switching arm 42, the third switching arm 43, and the fourth switching arm 44 are both ends of the series circuit 10a and 3 in the series circuit 10a. One point is connected to the midpoint of the phase coils 11, 12, and 13.

For the switching elements SW1 to SW8, for example, FETs are used. Parasitic diodes are formed in the switching elements SW1 to SW8, respectively.

The switching elements SW1 to SW8 perform switching operations in response to a control signal (switching signal) output from the switching control unit 5 described later, so that the coils 11 and 12 of each phase of the switch reluctance motor 2 from the DC power supply 31 are performed. , 13 is supplied with current.

By making the switching circuit 4 for driving the switched reluctance motor 2 in which the coils 11, 12, and 13 of each phase are connected in series into the above-described configuration, the total number of switching elements and diode elements required in the conventional configuration is totaled. The number of elements can be reduced as compared with (12).

Therefore, the switching circuit 4 can be realized by a compact configuration, and the switching circuit 4 can be manufactured at low cost.

The switching control unit 5 outputs a control signal for driving the switching elements SW1 to SW8 to the switching circuit 4. The switching control unit 5 has the coils 11, 12, of each phase of the stator 10 based on the current command value, the current value detected by the current detection unit 6, and the rotation position of the rotor (not shown) of the switched reluctance motor 2. The current flowing through 13 is controlled.

Specifically, the switching control unit 5 performs an operation mode (hereinafter, referred to as an operation mode of each phase) for controlling the current flowing through each phase of the switching circuit 4 based on the command signal and the rotation position of the rotor. In addition, a control signal for the switching elements SW1 to SW8 is generated. In the present embodiment, the operation mode of each phase includes a supply mode (first supply state, second supply state), a reflux mode, and a regeneration mode.

The supply mode is an operation mode in which the current is supplied to the coil so that the current flows from the DC power supply 31 to the coil, that is, the current flows from the high potential side to the low potential side of the coil. Therefore, in the supply mode, in the switching circuit 4, one of the switching elements SW1, SW3, SW5, SW7 of the upper arm 4a and one of the switching elements SW2, SW4, SW6, SW8 of the lower arm 4b are in the ON state, respectively.

The regeneration mode is an operation mode in which a current flows through the coil so that the current flows from the low potential side to the high potential side in the coil through which the current flows in the supply mode after the supply mode. In the coil in which the current flows in the supply mode, the current flows in the same direction as it is due to the energy of the inductance of the coil even after the end of the supply mode, so that the current flow in the regenerative mode as described above can be realized. In the regenerative mode, as in the supply mode, in the switching circuit 4, one of the switching elements SW1, SW3, SW5, SW7 of the upper arm 4a and one of the switching elements SW2, SW4, SW6, SW8 of the lower arm 4b are on. Is.

In the regenerative mode, the current flowing through the coil drops sharply.

The reflux mode is an operation mode in which a current flows through the coil so that the current flows between the same potentials in the coil through which the current flows in the supply mode after the supply mode. The reason why the current flows in the recirculation mode as described above is the same as the reason why the current flows in the coil in the regenerative mode described above. In the reflux mode, in the switching circuit 4, two switching elements among the switching elements SW1, SW3, SW5, and SW7 of the upper arm 4a, or two switching elements among the switching elements SW2, SW4, SW6, and SW8 of the lower arm 4b. Is on. In the reflux mode, a state in which a current flows through a portion of the switching circuit 4 and the coils 11, 12, and 13 corresponding to a predetermined phase is referred to as a reflux state in the predetermined phase of the switched reluctance motor unit 1.

In the reflux mode, the decrease in the current flowing through the coil is smaller than in the regeneration mode.

Of the above-mentioned operation modes, the supply mode and the reflux mode are energization modes for energizing the coil.

The switching control unit 5 includes a mode selection unit 51, a mode determination unit 52, a current determination unit 53, and a control signal generation unit 54.

The mode selection unit 51 switches the operation mode of each phase of the stator 10 based on the command signal and the rotation position of the rotor. Specifically, the mode selection unit 51 selects one operation mode of each phase of the stator 10 from the supply mode, the reflux mode, and the regeneration mode based on the command signal and the rotation position of the rotor. Set as the operation mode of each phase. In the present embodiment, the stator 10 has three phases, A phase, B phase, and C phase. Therefore, when the mode selection unit 51 sets the supply mode, only one of the three phases is used. To supply mode.

The mode selection unit 51 switches the operation mode of the predetermined phase to the reflux mode, for example, when switching the operation mode of the other phase to the energization mode after setting the predetermined phase to the energization mode. After that, the operation mode of the predetermined phase is switched to the regeneration mode.

Further, when the energization mode is set for only one phase, the mode selection unit 51 alternately switches the operation mode of the one phase between the supply mode and the reflux mode at a predetermined timing.

The mode determination unit 52 determines the operation mode of each phase of the stator 10 set by the mode selection unit 51. The mode determination unit 52 determines, for example, whether the operation mode of each phase of the stator 10 is the energization mode.

The current determination unit 53 determines whether or not a current is flowing through the coils 11, 12, and 13 of each phase of the stator 10 based on the current detected by the current detection unit 6. In the current determination unit 53, for example, when the energization mode is selected as the operation mode of the predetermined phase by the mode selection unit 51, is the current flowing in the phase in which the energization mode is set before the predetermined phase? Judge whether or not. The determination result of the current determination unit 53 is used when the control signal generation unit 54 generates a control signal for the switching elements SW1 to SW8 of the switching circuit 4.

The control signal generation unit 54 generates control signals for the switching elements SW1 to SW8 of the switching circuit 4 according to the operation mode of each phase set by the mode selection unit 51 and the determination result of the current determination unit 53, and switches. Output to circuit 4.

Specifically, the control signal generation unit 54 generates a control signal for driving the switching elements SW1 to SW8 so as to realize the operation mode of each phase set by the mode selection unit 51. Further, when the mode selection unit 51 selects the energization mode as the operation mode of the predetermined phase, the control signal generation unit 54 determines whether a current is flowing in the phase in which the energization mode is set before the predetermined phase. Depending on the situation, a switching pattern that realizes the reflux mode in the energization mode of the predetermined phase is selected from the two patterns to generate a control signal. At this time, the control signal generation unit 54 selects the switching pattern and generates a control signal so that the coils 11, 12, and 13 connected in series do not have a potential difference between the coils.

When the current flowing through the coil of the predetermined phase becomes zero, the control signal generation unit 54 stops the output of the control signal to the switching element driven to flow the current through the predetermined phase. , Turn off the switching element.

(Motor control operation)
Next, the motor control operation of the motor control device 3 having the above-described configuration will be described.

First, the operation modes (supply mode, regeneration mode, reflux mode) by the motor control device 3 will be described with reference to FIGS. 2 to 4. FIG. 2 is a diagram showing the current flow of the switching circuit 4 and the coils 11, 12 and 13 of each phase in the supply mode, and FIG. 3 is a diagram showing the current flow of the switching circuit 4 and the coils 11 and 12 of each phase in the regeneration mode. , 13, and FIG. 4 is a diagram showing the current flow of the switching circuit 4 and the coils 11, 12, and 13 of each phase in the recirculation mode.

Note that FIGS. 2 to 4 show the case where each phase is in the same mode for the sake of explanation, but in the actual operation of the switched reluctance motor 2, there is no case where each phase is in the same mode.

As shown in FIG. 2, when the A phase is set to the supply mode, the switching elements SW2 and SW3 are turned on. As a result, as shown by the solid line in FIG. 2, a current flows from the high potential side to the low potential side with respect to the A-phase coil 11. When the B phase is set to the supply mode, the switching elements SW4 and SW5 are turned on. As a result, as shown by the broken line in FIG. 2, a current flows from the high potential side to the low potential side with respect to the B-phase coil 12. When the C phase is set to the supply mode, the switching elements SW6 and SW7 are turned on. As a result, as shown by the alternate long and short dash line in FIG. 2, a current flows from the high potential side to the low potential side with respect to the C-phase coil 13.

As shown in FIG. 3, when the A phase is set to the regenerative mode, the switching elements SW1 and SW4 are turned on. Since the current flows through the A-phase coil 11 as shown by the solid arrow in FIG. 2 in the supply mode, the current flows through the coil 11 in the regenerative mode as shown by the solid arrow in FIG. As a result, as shown by the solid line in FIG. 3, a current flows from the low potential side to the high potential side with respect to the A-phase coil 11.

When the B phase is set to the regenerative mode, the switching elements SW3 and SW6 are turned on. Since the current flows through the B-phase coil 12 in the supply mode as shown by the broken line arrow in FIG. 2, the current flows through the B-phase coil 12 as shown by the broken line arrow in FIG. 3 even in the regenerative mode. As a result, as shown by the broken line in FIG. 3, a current flows from the low potential side to the high potential side with respect to the B-phase coil 12.

When the C phase is set to the regenerative mode, the switching elements SW5 and SW8 are turned on. Since the current flows through the C-phase coil 13 as shown by the alternate long and short dash arrow in FIG. 2 in the supply mode, the current flows through the coil 13 in the regenerative mode as shown by the alternate long and short dash arrow in FIG. As a result, as shown by the alternate long and short dash line in FIG. 3, a current flows from the low potential side to the high potential side with respect to the C-phase coil 12.

As shown in FIG. 4, when the A phase is set to the reflux mode, the switching elements SW2 and SW4 are turned on. Since the current flows through the A-phase coil 11 as shown by the solid arrow in FIG. 2 in the supply mode, the current flows through the coil 11 in the reflux mode as shown by the solid arrow in FIG. As a result, as shown by the solid line in FIG. 4, a current flows between the same potentials with respect to the A-phase coil 11.

When the B phase is set to the reflux mode, the switching elements SW4 and SW6 are turned on. Since the current flows through the B-phase coil 12 in the supply mode as shown by the broken line arrow in FIG. 2, the current flows through the B-phase coil 12 as shown by the broken line arrow in FIG. 4 even in the reflux mode. As a result, as shown by the broken line in FIG. 4, a current flows between the same potentials with respect to the B-phase coil 12.

When the C phase is set to the reflux mode, the switching elements SW5 and SW7 are turned on. Since the current flows through the C-phase coil 13 as shown by the alternate long and short dash arrow in FIG. 2 in the supply mode, the current flows through the coil 13 in the reflux mode as shown by the alternate long and short dash arrow in FIG. As a result, as shown by the alternate long and short dash line in FIG. 4, a current flows between the same potentials with respect to the C-phase coil 13.

In the present embodiment, when the C phase is set to the reflux mode, the switching elements SW5 and SW7 of the upper arm 4a operate in the switching circuit 4. On the other hand, when the other phase is set to the reflux mode, the switching elements SW2, SW4, and SW6 of the lower arm 4b operate in the switching circuit 4. That is, when the C phase is set to the reflux mode, among the upper and lower arms, an arm different from the case where the other phase is set to the reflux mode operates.

In the C-phase reflux mode, when the same lower arm 4b as when the other phase is set to the reflux mode is operated, when the A-phase is set to the supply mode, the A-phase coil 11 and the C-phase It is necessary to switch the switching element operated for the C-phase reflux mode from the lower arm 4b to the upper arm 4a so that a potential difference does not occur with the coil 13. In this case, when switching, the current flowing through the C-phase coil 13 may become discontinuous or a short circuit may occur.

On the other hand, according to the configuration of the present embodiment, when the C phase is set to the reflux mode, it is possible to prevent the current flowing through the C phase coil 13 from becoming discontinuous or causing a short circuit.

FIG. 5 shows an example of the operation mode of each phase together with the switching operation of the switching element in each operation mode. In the example shown in FIG. 5, a current is passed in the order of the A-phase coil 11, the B-phase coil 12, and the C-phase coil 13. In the operation mode shown in FIG. 5, "common" means a supply mode, "times" means a regeneration mode, and "return" means a reflux mode. Further, in the switching operation of the switching elements SW1 to SW8 in FIG. 5, the white portion corresponds to the A phase, the shaded portion corresponds to the B phase, and the shaded portion corresponds to the C phase. It is a switching operation to be performed.

In the case shown in FIG. 5, the timings at which currents flow through the coils 11, 12, and 13 of each phase do not overlap. As shown in FIG. 5, in the A-phase and B-phase reflux modes, the switching elements SW2, SW4, and SW6 of the lower arm 4b of the switching circuit 4 are operated, while in the C-phase reflux mode, the upper arm of the switching circuit 4 is operated. The switching elements SW5 and SW7 of 4a are operated.

The switching between the supply mode and the reflux mode in the energization mode is performed according to the current command value input to the switching control unit 5 and the current value detected by the current detection unit 6.

FIG. 6 is a flowchart showing the setting operation of the operation mode of each phase by the motor control device 3. The setting operation shown in FIG. 6 is performed for each phase in the motor control device 3. That is, in the case of the present embodiment, the setting operation shown in FIG. 6 is performed separately for each of the A phase, the B phase, and the C phase.

When the flow shown in FIG. 6 starts, the mode determination unit 52 of the switching control unit 5 determines whether or not the energization mode is set for the phase (hereinafter referred to as own phase) to be set by the flow (step). S1). When it is determined that the energization mode is set in the own phase (YES in step S1), the process proceeds to step S2, and the current determination unit 53 sets the energization mode before the own phase. It is determined whether or not a current is flowing in the forward direction (whether or not the current value is positive) in the phase (hereinafter referred to as the previous phase). On the other hand, if it is determined that the energization mode is not set in the own phase (NO in step S1), the process proceeds to step S9 to determine whether or not a current is flowing in the forward direction in the own phase.

If it is determined in step S2 that no current is flowing in the forward phase coil in the forward phase (NO), pattern 1 current control is performed for the own phase (step S3). In the current control of this pattern 1, the mode selection unit 51 sets the supply mode or the reflux mode with respect to the own phase. The supply mode and the reflux mode are set according to the current command value input to the switching control unit 5 and the current value detected by the current detection unit 6.

The supply mode of each phase in the current control of pattern 1 is the same as the supply mode of each phase shown in FIG. 2, and the reflux mode of each phase in the current control of pattern 1 is the reflux mode of each phase shown in FIG. The same is true.

On the other hand, in step S2, when it is determined that a current is flowing in the coil of the previous phase in the forward direction (YES), the current control of the pattern 2 is performed with respect to the own phase (step S4). In the current control of this pattern 2, the mode selection unit 51 sets the supply mode or the reflux mode with respect to the own phase. The supply mode and the reflux mode are set according to the current command value input to the switching control unit 5 and the current value detected by the current detection unit 6.

The supply mode of each phase in the current control of the pattern 2 is the same as the supply mode of each phase shown in FIG. On the other hand, the reflux mode of the A phase and the C phase in the current control of the pattern 2 is different from the reflux mode of each phase shown in FIG. 4, and is the reflux mode as shown in FIG. When a current is flowing through the coils of the previous phase, each phase in the current control of pattern 2 is used so that a potential difference does not occur between adjacent coils in the coils 11, 12, and 13 of each phase connected in series. The reflux mode needs to be changed from the reflux mode of each phase shown in FIG.

Specifically, when the A phase is set to the reflux mode, the switching elements SW1 and SW3 are turned on. When the C phase is set to the reflux mode, the switching elements SW6 and SW8 are turned on. In the current control of pattern 2, the B-phase reflux mode is the same as the B-phase reflux mode shown in FIG.

Therefore, in the current control of the pattern 2, the switching elements SW1 and SW3 of the upper arm 4a operate when the A phase is in the reflux mode, and the switching element of the lower arm 4b operates when the B phase and the C phase are in the reflux mode. SW4, SW6, SW8 operate.

Subsequently, in step S5, the mode determination unit 52 determines whether or not the next phase to be energized (hereinafter referred to as the next phase) is set to the energized mode. When it is determined that the next phase is set to the energization mode (YES), the mode selection unit 51 sets the own phase to the reflux mode (step S6). That is, in this step S6, the supply state (first supply state) in the energization mode of the own phase is switched to the supply state (second supply state) in the energization mode of the next phase.

The reflux mode is the same as the reflux mode of each phase shown in FIG. When switching from the supply mode of each phase shown in FIG. 1 to the reflux mode, in the A phase, the switching element SW4 is operated instead of the switching element SW3 while keeping the switching element SW2 in the ON state in the supply mode in the ON state. Let me. Further, in the B phase, the switching element SW6 is operated instead of the switching element SW5 while keeping the switching element SW4 in the ON state in the supply mode in the ON state. Further, in the C phase, the switching element SW5 is operated instead of the switching element SW6 while keeping the switching element SW7 in the ON state in the supply mode in the ON state.

On the other hand, when it is determined that the next phase is not set to the energization mode (NO), the process returns to step S1 and the determination of whether or not the own phase is set to the energization mode is performed again.

In step S7, which proceeds after the self-phase is set to the reflux mode, the mode determination unit 52 determines whether or not the self-phase is set to the energization mode. If it is determined that the own phase is set to the energization mode (YES), the process returns to step S6 to continue setting the return mode of the own phase, while the own phase is set to the energization mode. If it is determined that there is no such condition (NO), the process proceeds to step S8, and the mode selection unit 51 sets the self-phase to the regeneration mode. This regeneration mode is the same as the regeneration mode of each phase shown in FIG.

In step S9, which proceeds after setting the own phase to the regenerative mode in step S8, the current determination unit 53 determines whether or not a current is flowing in the coil of the own phase in the forward direction (whether or not the current value is positive). .. If it is determined that a current is flowing in the self-phase coil in the forward direction (YES), the process returns to step S8 to continue setting the self-phase regeneration mode, while continuing to set the self-phase regeneration mode. When it is determined that no current is flowing in the direction (NO), all the switching elements used to pass the current through the self-phase coil are turned off.

After that, it is determined whether or not the switched reluctance motor 2 has finished the operation mode (step S11). When it is determined that the switched reluctance motor 2 has terminated the operation mode (YES), this flow is terminated (end). On the other hand, when it is determined that the switched reluctance motor 2 has not ended the operation mode (NO), the process returns to step S1 and the determination as to whether or not the own phase is in the energization mode is performed again.

Step S5 corresponds to the supply state detection step, and step S6 corresponds to the recirculation step.

FIG. 8 shows an example in which the operation mode of each phase is set according to the above flow. FIG. 8 also shows the switching operation of the switching element according to the operation mode for the coils 11, 12, and 13 of each phase.

In the operation mode shown in FIG. 8, “common” means a supply mode, “times” means a regeneration mode, and “return” means a reflux mode. Further, in the switching operation of the switching elements SW1 to SW8 in FIG. 8, the white portion corresponds to the A phase, the shaded portion corresponds to the B phase, and the shaded portion corresponds to the C phase. It is a switching operation to be performed. In the switching operation of the switching element, the portion surrounded by bold indicates the case where the ON state of the switching element operated in the own phase and the ON state of the switching element operated in the next phase overlap.

As shown in FIG. 8, when the own phase is in the energization mode (supply mode) and the next phase is in the energization mode (supply mode), the own phase is switched to the reflux mode. After that, the self-phase is switched to the regenerative mode.

In this way, when the self-phase is in the energization mode (supply mode) and the next phase is in the energization mode (supply mode), the self-phase is switched to the reflux mode instead of the regeneration mode. It is possible to suppress a sudden decrease in the current flowing through the phase coil. Therefore, as described below, the output torque of the switched reluctance motor 2 can be made larger than that in the case of switching the self-phase from the supply mode to the regenerative mode.

As an example, FIG. 9 schematically shows changes in the current flowing through each phase and the inductance of the coils 11 and 12 of each phase when the A-phase energization mode is switched to the B-phase energization mode. In FIG. 9, the change in the current (A-phase current) flowing through the A-phase coil 11 in the operation mode of the present embodiment is shown by a thick solid line, and the current flowing through the B-phase coil 12 (the current flowing through the B-phase coil 12) in the operation mode of the present embodiment is shown by a thick solid line. The change in B-phase current) is shown by a thick broken line. Further, in FIG. 9, the change in the inductance of the A-phase coil 11 is shown by a solid line in the operation mode of the present embodiment, and the change in the inductance of the B-phase coil 12 is shown by a broken line in the operation mode of the present embodiment. Note that FIG. 9 shows a change in the current flowing through the A-phase coil 11 when the A-phase is set from the supply mode to the regenerative mode by a alternate long and short dash line.

As shown in FIG. 9, when switching from the A-phase energization mode to the B-phase energization mode, the supply mode is switched to the regeneration mode by switching the A phase from the supply mode to the reflux mode as in the present embodiment. A large amount of current (A-phase current) can be passed through the A-phase coil 11. That is, according to the configuration of the present embodiment, the current in the region shown by the shaded area in FIG. 9 increases.

Moreover, by switching the A phase from the supply mode to the reflux mode as in the present embodiment, the coil 11 has a larger current (A phase) as described above during the period when the inductance of the coil 11 of the A phase has a positive inclination. Current) can flow. Therefore, it is possible to generate a large positive torque in the switched reluctance motor 2 as compared with the conventional configuration.

As shown in FIG. 8, when a current is flowing through the coil of the previous phase (in the example of FIG. 8, when the previous phase is in the regeneration mode) and the next phase is in the recirculation mode, the next phase is the A phase. Alternatively, in the case of the C phase, the switching element that operates in the return mode of the next phase is different from the switching element that operates when no current flows through the coil of the previous phase. This makes it possible to prevent a potential difference between the B-phase coil 12 and the C-phase coil 13 when the B-phase is in the reflux mode and the regeneration mode, and the C-phase is in the reflux mode and the regeneration mode. At this time, it is possible to prevent a potential difference from occurring between the C-phase coil 13 and the A-phase coil 11.

Based on the above, according to the configuration of the present embodiment, the switched reluctance motor 2 having the three-phase coils 11, 12, 13 connected in series and the motor control device 3 having the switching circuit 4 are provided. In the reluctance motor unit 1, the midpoint of an arm having a pair of switching elements connected in series is connected to the midpoint and the end point of the coils one by one. As a result, the number of elements in the switching circuit 4 can be reduced as compared with the conventional configuration. Therefore, the switched reluctance motor unit 1 can be miniaturized and the manufacturing cost can be reduced.

Moreover, in the switched reluctance motor unit 1, when the self-phase is set to the energization mode by the motor control device 3, when the next phase is set to the energization mode, the self-phase is set to the reflux mode. As a result, it is possible to prevent the timings of the supply modes from overlapping in a plurality of phases, and it is possible to suppress a decrease in the current flowing through the coil of the own phase as compared with the case where the own phase is changed from the supply mode to the regenerative mode. Therefore, the output torque of the switched reluctance motor 2 can be increased as compared with the case where the self-phase is changed from the supply mode to the regenerative mode.

Further, in the configuration of the present embodiment, when a current flows through only one phase of the coil, in the A phase and the B phase, the switching element that operates in the reflux mode is the switching element of the lower arm 4b of the switching circuit 4. In the C phase, the switching element that operates in the reflux mode is the switching element of the upper arm of the switching circuit 4. In this way, by changing the operating arm of the upper and lower arms in the reflux mode only for the C phase, the switching element of the C phase that operates when the C phase is in the reflux mode and the A phase is set to the energization mode can be obtained. There is no need to change from the lower arm to the upper arm. Therefore, it is possible to prevent the current flowing through the C-phase coil 13 from becoming discontinuous or causing a short circuit.

Further, in the configuration of the present embodiment, when the current is flowing through the coil of the previous phase and the next phase is set to the reflux mode, if the next phase is the A phase or the C phase, those phases. In the recirculation mode of, a switching element different from the switching element that operates in the normal recirculation mode (a state in which no current is flowing through the coil of the previous phase) is operated. That is, in the return mode of the A phase or the C phase, which is the next phase, the switching element of the upper and lower arms of the switching circuit 4 that is different from the arm that operates in the normal return mode is operated. This makes it possible to prevent a potential difference from occurring in the coils 11, 12, and 13 of the respective phases connected in series when the next phase is set to the reflux mode when a current is flowing through the coil of the previous phase. ..

(Other embodiments)
Although the embodiments of the present invention have been described above, the above-described embodiments are merely examples for carrying out the present invention. Therefore, the embodiment is not limited to the above-described embodiment, and the above-described embodiment can be appropriately modified and implemented within a range that does not deviate from the gist thereof.

In the embodiment, the switched reluctance motor 2 has a three-phase coil. However, the switched reluctance motor may have two-phase coils or may have four or more phases of coils. That is, the switched reluctance motor may have a plurality of phases of coils.

Even when the switched reluctance motor has a plurality of phase coils, the plurality of phase coils are connected in series.

In the above embodiment, the switching elements that operate in the C-phase reflux mode are the switching elements SW5 and SW7 of the upper arm 4a of the switching circuit 4. However, the switching element that operates in the C-phase reflux mode may be the switching element of the lower arm 4b of the switching circuit 4. In this case, when the next phase (A phase in this embodiment) is switched to the supply mode, the switching element that operates in the C-phase reflux mode is replaced with the switching elements SW5 and SW7 of the upper arm 4a of the switching circuit 4. Need to switch to.

In the above embodiment, in the C-phase reflux mode, the switching elements SW5 and SW7 of the upper arm 4a of the switching circuit 4 operate, and in the A-phase and B-phase reflux modes, the switching element SW2 of the lower arm 4b of the switching circuit 4 operates. , SW4, SW6 are operating. However, in the A-phase reflux mode, the switching element of the upper and lower arms, which is different from the arm operating in the reflux mode of the other phase, may be operated. For example, in the reflux mode of the A phase, the B phase, and the C phase, the switching element of the same arm among the upper and lower arms may be operated.

When the current flow in the switching circuit 4 is opposite to that in the switching circuit 4, the on and off states of the switching elements SW1 to SW8 in the switching circuit 4 are opposite to those in the embodiment. become.

The present invention can be used in a switched reluctance motor unit including a switched reluctance motor in which a plurality of phases of coils are connected in series.

1 Switch trilactans motor unit 2 Switch trilatance motor 3 Motor control device 4 Switching circuit 4a Upper arm 4b Lower arm 5 Switching control unit 6 Current detector 10 Stator 10a Series circuit 11 A-phase coil 12 B-phase coil 13 C-phase coil 31 DC power supply 32 Capacitor 41 1st arm 42 2nd arm 43 3rd arm 44 4th arm 51 Mode selection unit 52 Mode determination unit 53 Current determination unit 54 Control signal generation unit SW1 to SW8 Switching element

Claims (4)

A switched reluctance motor with multiple phase coils connected in series,
A motor control device that controls the drive of the switched reluctance motor by supplying an electric current to the coils of the plurality of phases.
With
The motor control device is
A switching circuit in which a plurality of switching arms configured by connecting a pair of switching elements in series are connected in parallel, and a switching circuit.
A switching control unit that controls the drive of the switching element,
Have,
The midpoint of the pair of switching elements in the plurality of switching arms is both ends of a series circuit formed by connecting the coils of the plurality of phases in series, and the coils of the plurality of phases in the series circuit. One point is connected to each other's midpoint,
The pair of switching elements form an upper arm and a lower arm of the switching arm, respectively.
The switching control unit
The switching elements of the upper arm and the lower arm are turned on so that the current flows from the high potential side to the low potential side in the coil of one of the plurality of phases.
After the supply state, the switching element of only one of the upper arm and the lower arm is placed so as to be in a reflux state in which the current continues to flow in the direction in which the current flows to the coil of the one phase in the supply state. Turn it on and
By driving the pair of switching elements in the plurality of switching arms, a current flows from the high potential side to the low potential side with respect to the coil of one of the coils of the plurality of phases from the first supply state. When switching to the second supply state in which the current flows from the high potential side to the low potential side with respect to the coils of the other phases and switching to the second supply state, the current returns to the coils of the one phase. A switch trilatance motor unit that drives a switching element so as to be in the recirculation state . In the switched reluctance motor unit according to claim 1.
The switching control unit has the upper arm and the lower arm so that when the first supply state is switched to the second supply state, the current flows back to the coil of the one phase. A switched reluctance motor unit that turns on a switching element of the same arm as the switching element that is turned on in the first supply state. In the switched reluctance motor unit according to claim 1 or 2.
The switching control unit
When the current is recirculated to the coil of at least one phase of the plurality of phases in the recirculated state, the current is recirculated to the coil of the other phase of the upper arm and the lower arm. A switched reluctance motor unit that turns on the switching element of an arm other than the arm that turns on the switching element when the current is returned. A switched reluctance motor with multiple phase coils connected in series,
A plurality of switching arms configured by connecting a pair of switching elements in series are connected in parallel, and the midpoint of the pair of switching elements is connected in series by the coils of the plurality of phases. A switching circuit connected to both ends of the series circuit and the midpoints of the coils of the plurality of phases in the series circuit one by one.
It is a control method of the switched reluctance motor unit equipped with
In the first supply state in which a current flows from the high potential side to the low potential side with respect to the coil of one phase of the coils of the plurality of phases by driving the pair of switching elements in the plurality of switching arms. A supply state detection step for detecting a second supply state in which a current flows from a high potential side to a low potential side with respect to coils of other phases, and a supply state detection step.
When the second supply state is detected, the upper arm and the upper arm each of the pair of switching elements are formed in the plurality of switching arms so that the current flows back to the coil of the one phase. A method for controlling a switchd reluctance motor unit, comprising a reflux step of turning on a switching element of the same arm as the switching element which is turned on in the first supply state among the lower arms.

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