JP2013115901A - Turning force generation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a turning force generation device free from variation in torque waveform even when a winding connection state of a phase winding is switched.SOLUTION: A turning force generation device, when switching "from series connection to parallel connection" or "from parallel connection to series connection" for a phase winding by using torque T and the number of rotations N, performs the switching in timing when the phase winding is not supplied with electricity, and controls a current waveform of the phase winding to make torque waveforms substantially identical between just before the switching and just after the switching. This allows an SR motor 1 to obtain high output in a wide operation range, prevent torque variation caused by the switching of a winding group during electric power supply to the phase winding, and also prevent variation in torque waveform when the switching of the phase winding changes the inductance of the winding group.

Description

  The present invention relates to a rotational force generator using an electric motor equipped with a “phase winding” composed of “a winding set capable of switching the connection state of windings”, and more particularly, to a technique for switching a winding set.

The output of an electric motor (such as an SR motor) generally depends on “the number of turns of a phase winding (the number of turns of a coil)”.
Specifically, when the “number of turns of the phase winding” is large, the output of the electric motor generates a large output in the low rotation range, but the output decreases in the high rotation range. Conversely, when the “number of turns of the phase winding” is small, a large output is generated in the high rotation range, but the output is reduced in the low rotation range.

Thus, a technique has been proposed in which a large output is obtained in each of the low rotation range and the high rotation range by switching the “number of turns of the phase winding” in accordance with the rotation number (see, for example, Patent Document 1).
This Patent Document 1 provides a “phase winding” by “a winding set capable of switching the connection state of windings”, and (i) a “winding set to increase the number of turns” in a low rotation range. (Ii) This is a technique for switching the “winding set so that the number of turns is reduced” in the high rotation range.

  However, the technique of Patent Document 1 has a problem that the torque waveform suddenly changes at the switching execution timing because the inductance of the winding group changes suddenly at the switching timing of the winding group.

Japanese Patent No. 3702713

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a torque generator that does not cause fluctuations in the torque waveform of an electric motor even when the winding group is switched. .

[Means of Claim 1]
The torque generator according to claim 1 controls the current waveform of the phase winding by an energization control command unit provided in the control circuit, so that the torque waveform immediately before and after the switching of the winding group is the same waveform (increase / decrease in output). And a slight increase / decrease in the waveform accompanying the increase / decrease in the duty ratio of the switch).
As a result, even if the winding group is switched and the inductance of the winding group changes, fluctuations in the torque waveform of the electric motor can be prevented.

[Means of claim 2]
The energization control command unit according to claim 2 controls the winding applied voltage average value immediately before and after the switching of the winding group to the turn ratio immediately before and after the switching.
As a result, even if the inductance changes due to the switching of the winding group, the torque waveforms immediately before and after the switching of the winding group can be made substantially the same.

[Means of claim 3]
According to a third aspect of the present invention, the first switching command unit, the second switching command unit, and the switching execution circuit switch the winding group at a timing when the energization state of the phase winding is not energized.
As a result, it is possible to avoid torque fluctuations caused by switching the winding group while the phase winding is energized.

[Means of claim 4]
The first switching command unit according to claim 4 determines the switching state of the winding set by using “the torque of the electric motor” and “the rotational speed of the electric motor”.
Thereby, a high output can be obtained from the electric motor in a wide operation range from a low rotation range to a high rotation range.

[Means of claim 5]
The second switching command unit according to claim 5 is a switching execution circuit using three conditions of “a determined state of the first switching command unit”, “a current winding set switching state”, and “a phase winding current value”. Is given a switching command.
As a result, it is possible to avoid torque fluctuations caused by switching the winding group while the phase winding is energized.

[Means of claim 6]
The energization control command unit according to claim 6 switches the control parameter in accordance with the switching of the winding group.
Thus, even if the inductance changes due to the switching of the winding group, the torque waveforms immediately before and after the switching of the winding group can be made substantially the same.

(A) Schematic diagram of SR motor, (b) Drive circuit diagram of each phase winding (Example 1). FIG. 3 is a schematic block diagram of a control circuit (Example 1). (A) The graph which shows the output torque with respect to the rotation speed used for operation | movement description of a 1st switching command part, (b) The chart which shows the relationship between 3 conditions used for operation | movement description of a 1st switching command part, and the presence or absence of a switching command ( Example 1). 6 is a flowchart illustrating an example of winding group switching control (Example 1); It is a time chart for operation | movement description (Example 1). (Example 2) which is a schematic block diagram of a control circuit. (A) Schematic diagram of SR motor, (b) Drive circuit diagram of each phase winding (Example 3). (A) Schematic diagram of SR motor, (b) Drive circuit diagram of each phase winding (Embodiment 4). (A) Schematic of stepping motor, (b) Drive circuit diagram of phase winding (modification).

[Description of Embodiments] [Mode for carrying out the invention] will be described with reference to the drawings.
The rotational force generator includes an SR motor 1 (an example of an electric motor) equipped with a “phase winding” composed of a “winding set capable of switching the connection state of the windings”, and an operating state of the SR motor 1. And a control circuit 2 for switching the winding group accordingly.

The control circuit 2
(A) a first switching command unit 3 that determines the connection state (switching state) of the winding set based on the operating state (rotation speed N, torque T, etc.) of the SR motor 1;
(B) when the first switching command unit 3 determines to switch the winding group, a second switching command unit 4 that issues a switching command for the winding group at the timing when the energization state of the phase winding is not energized;
(C) a switching execution circuit 5 that executes switching of the winding group based on the switching command of the second switching command unit 4;
(D) an energization control command unit 6 that controls the current waveform of the phase winding;
(E) an energization control execution circuit 7 that executes energization control of the phase winding based on an instruction of the energization control command unit 6;
It comprises.

Then, the energization control command unit 6 indicates that the torque waveform immediately before and after the switching of the winding group is the same when the switching of the winding group is executed (the slight waveform accompanying the increase / decrease in the output or the increase / decrease in the duty ratio of the switch). The current waveform of the phase winding is controlled so that
As a result, even if the winding group is switched during the operation of the SR motor 1, fluctuations in the torque waveform of the SR motor 1 can be prevented.

Hereinafter, a specific example (example) of the present invention will be described with reference to the drawings. The following examples show specific examples, and it goes without saying that the present invention is not limited to the examples.
In the following examples, the same reference numerals as those in the “DETAILED DESCRIPTION OF THE INVENTION” denote the same functional objects.

[Example 1]
A first embodiment will be described with reference to FIGS.
In this embodiment, an SR motor 1 (switched reluctance motor) is used as an example of an electric motor, and the SR circuit 1 is energized and controlled by a control circuit 2. Although the application of the SR motor 1 is not limited, as a specific example, in this embodiment, the SR motor 1 is mounted on a vehicle for driving a vehicle (for driving a vehicle) such as an electric vehicle or a hybrid vehicle. .

(Description of SR motor 1)
The SR motor 1 includes a stator core 11 having a plurality of phase windings, and a rotor core 12 that is rotatably supported with respect to the stator core 11.
The number of phases of the phase winding is not limited, but in this embodiment, an example using three phases of an A phase winding, a B phase winding, and a C phase winding is shown as a specific example.

A specific example of the SR motor 1 will be described with reference to FIG.
The stator core 11 of this embodiment includes a back yoke 14 that magnetically couples the stator teeth 13 in addition to the twelve stator teeth 13 (stator salient poles) 13 arranged at equal intervals between the mechanical angles of 360 degrees. Prepare.

Specifically, the SR motor 1 of the first embodiment is an inner rotor type in which a rotor core 12 is disposed inside a stator core 11.
For this reason, the stator core 11 according to the first embodiment has an annular back yoke 14 fixedly disposed in the motor housing (specifically, in a cylindrical yoke), and 12 projects in the inner diameter direction from the back yoke 14. The stator teeth 13 are provided.
More specifically, the stator core 11 is formed by laminating a large number of electromagnetic steel plates (soft iron plate, silicon steel plate, amorphous metal plate, etc.) having an insulating film formed on the surface thereof.

The rotor core 12 of this embodiment includes eight rotor teeth (rotor salient poles) 15 arranged at equal intervals between mechanical angles of 360 degrees, and a ring core 16 coupled to the rotor shaft (output shaft).
Specifically, the SR motor 1 of the first embodiment is an inner rotor type as described above. For this reason, the rotor core 12 of the first embodiment includes a ring core 16 that is fixed around the rotor shaft that is rotatably supported via a bearing with respect to the motor housing, and eight pieces that protrude from the ring core 16 in the outer diameter direction. The rotor teeth 15 are provided.
More specifically, the rotor core 12 is formed by laminating a large number of electromagnetic steel plates (soft iron plate, silicon steel plate, amorphous metal plate, etc.) having an insulating film formed on the surface, like the stator core 11 described above.

  Here, the axis of the stator core 11 and the axis of the rotor core 12 are arranged coaxially, and when the rotor core 12 rotates, the stator teeth 13 and the rotor teeth 15 are not in contact with each other, and the stator teeth 13 and the rotor are not in contact with each other. A clearance is formed between the stator teeth 13 and the rotor teeth 15 when the teeth 15 face each other.

(Description of phase winding in SR motor 1)
As described above, the SR motor 1 of this embodiment is mounted with the A-phase winding, the B-phase winding, and the C-phase winding as means for switching and exciting the stator teeth 13.
The A-phase winding is composed of independent first A winding 1A and second A winding 2A. The first A winding 1A and the second A winding 2A constitute an A winding set capable of switching the connection state.
The B-phase winding is composed of independent first B winding 1B and second B winding 2B. The first B winding 1B and the second B winding 2B constitute a B winding set capable of switching the connection state.
The C-phase winding is composed of an independent first C winding 1C and second C winding 2C. The first C winding 1C and the second C winding 2C constitute a C winding set capable of switching the connection state.

In FIG. 1 (a), only the A-phase winding (the first A winding 1A and the second A winding 2A) is shown, and the B-phase winding (the first B winding 1B and the second B) is shown for assisting understanding. The winding 2B) and the C-phase winding (the first C winding 1C and the second C winding 2C) are omitted.
Further, in the following description of the control of the phase winding, there will be a description of a control example of the A phase winding and a description of the control examples of the B phase winding and the C phase winding will be omitted. The winding and the C-phase winding are controlled similarly to the A-phase winding.

The first A winding 1A is wound around two stator teeth 13 facing each other by 180 degrees, and when the first A winding 1A is energized, the two stators around which the first A winding 1A is wound The teeth 13 are excited to different magnetic poles.
The second A winding 2A is wound around two stator teeth 13 opposed to each other by 180 degrees at a position different from the stator teeth 13 excited by the first A winding 1A by 90 degrees in the rotational direction. When the wire 2A is energized, the two stator teeth 13 around which the second A winding 2A is wound are excited to different magnetic poles.

  Here, in order to clarify the relevance between the first A winding 1A and the second A winding 2A in FIG. 1A and the first A winding 1A and the second A winding 2A in FIG. The coil ends of the first A winding 1A are indicated by symbols A1 and A1 ′, and the coil ends of the second A winding 2A are indicated by symbols A2 and A2 ′.

Although not shown in FIG. 1A, “first and second B windings 1B and 2B” forming a B-phase winding and “first and second C windings 1C and 2C” forming a C-phase winding are also included. , Adopting the same configuration as the "first and second A windings 1A, 2A" forming the above-described A phase winding,
The "first and second B windings 1B and 2B" forming the B-phase winding are the stator teeth 13 wound with the "first and second A windings 1A and 2A" forming the A-phase winding. , Provided in the stator teeth 13 at positions rotated 60 degrees counterclockwise in FIG.
The "first and second C windings 1C and 2C" forming the C-phase winding are in contrast to the stator teeth 13 wound with the "first and second B windings 1B and 2B" forming the B-phase winding. , The stator teeth 13 are provided at positions rotated 60 degrees counterclockwise in FIG.

(Description of control circuit 2)
Next, the control circuit 2 that controls the energization of the SR motor 1 will be described.
As shown in FIG.
(A) a first switching command unit 3 that determines a connection state (series connection or parallel connection) based on the operation state of the SR motor 1;
(B) When the first switching command unit 3 decides to switch the winding group, the switching instruction (series-> parallel switching instruction) is performed when the A-phase winding, the B-phase winding, and the C-phase winding are de-energized. Or a second switching command unit 4 for generating a parallel → series switching instruction),
(C) Switching for switching the A-phase winding, the B-phase winding, and the C-phase winding (series-> parallel switching or parallel-> series switching) based on the switching command of the second switching command unit 4 An execution circuit 5;
(D) an energization control command unit 6 for controlling the current waveform of each phase winding (A phase winding, B phase winding, C phase winding);
(E) Drive power V is applied to each phase winding (A phase winding, B phase winding, C phase winding) based on a control signal (duty ratio signal α) output by the energization control command unit 6. An energization control execution circuit 7.

(Description of the first switching command unit 3)
The first switching command unit 3
-"Torque T" of SR motor 1,
-"Rotation speed N" of SR motor 1,
Using these two conditions, the switching state of each winding group (A winding group, B winding group, C winding group) is determined as one of “series connection or parallel connection”.
The first switching command unit 3 does not use the “torque T”, and each winding group (A winding group, B winding group, C winding group) based on the “rotational speed N” of the SR motor 1. The switching state may be determined as one of “series connection or parallel connection”.

Specifically, the first switching command unit 3 of the first embodiment is a control program installed in the control circuit 2.
When the control program of the control circuit 2 enters the control routine of the SR motor 1 (see the start in FIG. 4),
"Request torque T" required by the ECU for the SR motor 1,
A “rotation number N” of the SR motor 1 detected by a rotation sensor (a sensor for detecting the rotation number N of the SR motor 1);
(See step S1 in FIG. 4).

Next, the first switching command section 3 has the relationship shown in FIG. 3A (the relationship between “torque T” and “rotation speed N” in series connection, “torque T” and “rotation speed N in parallel connection”. ”), A connection state (one of serial connection or parallel connection) is determined from“ required torque T ”and“ rotational speed N ”(see step S2 in FIG. 4).
This determination is made by using a map mounted on the memory of the control circuit 2 or a calculation formula.

(I) A specific example when the first switching command unit 3 determines to switch the connection state from “series connection to parallel connection” is shown at timing T1 in FIG.
(Ii) Conversely, a specific example when the first switching command unit 3 determines to switch the connection state from “parallel connection to series connection” is shown at a timing T2 in FIG.

(Description of second switching command unit 4)
The second switching command unit 4 is a control program installed in the control circuit 2,
As shown in FIG.
(Α) the determination state (series connection or parallel connection) of the first switching command unit 3;
(Β) Current winding set switching state (series connection or parallel connection),
(Γ) phase winding current value I;
Based on these three conditions, a switching instruction is given to the switching execution circuit 5.

The above (α) will be described.
The control program of the second switching command unit 4 determines whether the connection state determined by the first switching command unit 3 (see step S2 in FIG. 4) described above is “series connection” or “parallel connection”. Perform (see step S3 in FIG. 4).

The above (β) will be described.
When the control program of the second switching command unit 4 determines that the connection state determined by the first switching command unit 3 is “series connection” (when the determination result of step S3 in FIG. 4 is YES), the current program It is determined whether or not the connection state is the connection state determined by the first switching command unit 3 (that is, serial connection) (see step S4 in FIG. 4).
If the current connection state is the connection state determined by the first switching command unit 3 (that is, serial connection), the switching execution circuit 5 is not given a switching instruction, and the current connection state (that is, serial connection). Is maintained (see step S5 in FIG. 4).

On the contrary, when it is determined that the connection state determined by the first switching command unit 3 is “parallel connection” (when the determination result of step S3 in FIG. 4 is NO), the current connection state is It is determined whether or not the connection state determined by the 1-switching command unit 3 (ie, parallel connection) (see step S6 in FIG. 4).
When the current connection state is the connection state determined by the first switching command unit 3 (that is, parallel connection), the switching execution circuit 5 is not given a switching instruction, and the current connection state (that is, parallel connection). Is maintained (see step S7 in FIG. 4).

The above (γ) will be described.
When the current connection state is different from the serial connection determined by the first switching command unit 3 (when the determination result of step S4 in FIG. 4 is NO), the control program of the second switching command unit 4 is a current sensor ( It is determined whether or not the current value I of the phase winding to be switched detected by a sensor that detects the current value I for each phase winding is 0 (see step S8 in FIG. 4). .
When a current is flowing through the phase winding to be switched, the switching execution circuit 5 is not given a switching instruction, and the current connection state (that is, serial connection) is maintained (see step S5 in FIG. 4).
When the phase winding to be switched is de-energized (see timing T3 in FIG. 5), a switching instruction to switch from “parallel connection to series connection” is given to the switching execution circuit 5 (see step S9 in FIG. 4).

Contrary to the above, when the current connection state is different from the parallel connection determined by the first switching command unit 3 (when the determination result of step S6 in FIG. 4 is NO), the switching target detected by the current sensor It is determined whether or not the current value I of the phase winding is 0 (zero) (see step S10 in FIG. 4).
When a current is flowing through the phase winding to be switched, the switching execution circuit 5 is not given a switching instruction, and the current connection state (ie, parallel connection) is maintained (see step S7 in FIG. 4).
When the phase winding to be switched is de-energized (see timing T4 in FIG. 5), a switching instruction to switch from “series connection to parallel connection” is given to the switching execution circuit 5 (see step S11 in FIG. 4).

(Description of the switching execution circuit 5)
The switching execution circuit 5 uses a plurality of switches to “1A winding 1A and 2A winding 2A”, “1B winding 1B and 2B winding 2B”, “1C winding 1C and 2C winding”. This is a switching circuit that switches each of the lines 2C to one of series connection or parallel connection.

A specific example of the switching execution circuit 5 will be described with reference to FIG.
In the energization circuit of the A phase winding (the first A winding 1A, the second A winding 2A),
A first A winding short-circuit switch SWpa1 that bypasses the first A winding 1A and flows electricity is provided,
A second A winding short-circuit switch SWpa2 that bypasses the second A winding 2A and flows electricity is provided,
An A changeover switch SWsa is provided for switching between the coil end A1 ′ of the first A winding 1A and the coil end A2 of the second A winding 2A.

  These three switches (the first A winding short-circuit switch SWpa1, the second A winding short-circuit switch SWpa2, and the A switching switch SWsa) are switched by the switching instruction of the second switching command unit 4 described above. In other words, the “first A winding 1A and the second A winding 2A” are switched to one of “series connection or parallel connection” in accordance with the switching instruction of the second switching command unit 4.

Specifically, switching between “series connection and parallel connection” is as shown in Table 1 below.
(I) By turning on the A changeover switch SWsa and turning off the first A winding short-circuit switch SWpa1 and the second A winding short-circuit switch SWpa2 (refer to the section less than the timing T3 and the section more than the timing T4 in FIG. 5). The first A winding 1A and the second A winding 2A are connected in series,
(Ii) By turning off the A selector switch SWsa and turning on the first A winding short-circuit switch SWpa1 and the second A winding short-circuit switch SWpa2 (see the section of timings T3 to T4 in FIG. 5), the first A winding 1A And the second A winding 2A are connected in parallel.

Similarly to the above, the energization circuit of the B phase winding (the first B winding 1B and the second B winding 2B)
A first B winding short-circuit switch SWpb1 that bypasses the first B winding 1B and flows electricity is provided;
A second B winding short-circuit switch SWpb2 that bypasses the second B winding 2B and flows electricity is provided,
A B change-over switch SWsb that switches between the first B winding 1B and the second B winding 2B is provided.

  The three switches (the first B winding short-circuit switch SWpb1, the second B winding short-circuit switch SWpb2, and the B switch SWsb) are switched by the switching instruction of the second switching command unit 4 described above. That is, the “first B winding 1B and the second B winding 2B” are switched to one of “series connection or parallel connection” in accordance with the switching instruction of the second switching command unit 4.

Similarly, in the energization circuit of the C-phase winding (the first C winding 1C and the second C winding 2C),
A first C winding short-circuit switch SWpc1 that bypasses the first C winding 1C and flows electricity is provided,
A second C winding short-circuit switch SWpc2 that bypasses the second C winding 2C and flows electricity is provided;
A C changeover switch SWsc is provided for switching between the first C winding 1C and the second C winding 2C.

  These three switches (the first C winding short-circuit switch SWpc1, the second C winding short-circuit switch SWpc2, and the C switching switch SWsc) are switched by the switching instruction of the second switching command unit 4 described above. That is, the “first C winding 1C and the second C winding 2C” are switched to one of “series connection or parallel connection” in accordance with the switching instruction of the second switching command unit 4.

(Description of energization control execution circuit 7)
The energization control execution circuit 7 is a circuit that causes a current to flow through the A-phase winding, the B-phase winding, and the C-phase winding using a plurality of switches and a plurality of diodes.

A specific example of the energization control execution circuit 7 will be described with reference to FIG.
The energization control execution circuit 7
A phase winding switch means SWap, SWan for applying a battery voltage to the A phase winding (including the first A winding shorting switch SWpa1, the second A winding shorting switch SWpa2, the A changeover switch SWsa),
-B-phase winding switch means SWbp, SWbn for applying a battery voltage to the B-phase winding (including the first B winding short-circuit switch SWpb1, the second B winding short-circuit switch SWpb2, and the B changeover switch SWsb);
-C-phase winding switch means SWcp, SWcn for applying a battery voltage to the C-phase winding (including the first C winding short-circuit switch SWpc1, the second C winding short-circuit switch SWpc2, C switching switch SWsc),
-Diodes Da1 and Da2 for passing an induction current through the A-phase winding,
-Diodes Db1 and Db2 for flowing an induction current through the B-phase winding,
-Diodes Dc1 and Dc2 for passing an induction current through the C-phase winding,
It is configured with.

  Then, each phase winding switch means SWap, SWan, SWbp, SWbn, SWcp, SWcn repeats “ON / OFF at high speed” by the duty ratio signal α given from the energization control command section 6 to each phase winding ( The driving power V is supplied from the battery BAT to the A-phase winding, the B-phase winding, and the C-phase winding.

(Description of energization control command unit 6)
The energization control command unit 6 determines the supply current value (specifically, the duty ratio) of each phase winding (A phase winding, B phase winding, C phase winding) based on the required torque T given from the ECU. Based on the calculated duty ratio and the “rotation number N” and “rotation angle θ” of the SR motor 1 detected by the rotation sensor, the energization control execution circuit 7 (switch means SWap, SWan for each phase winding, SWbp, SWbn, SWcp, SWcn) are controlled.

  In addition, the energization control command unit 6 adjusts the phase so that the torque waveform immediately before and after the switching of the winding group becomes the same waveform (including slight increase / decrease of the waveform due to increase / decrease of the output or increase / decrease of the duty ratio of the switch). Controls the current waveform of the winding.

A specific example will be described with reference to FIG.
When switching the winding group from “series connection to parallel connection”, assuming that the torque waveform immediately before switching is the waveform X1 in FIG. 5, the torque waveform immediately after switching the winding group from “series connection to parallel connection” is “ The energization control command unit 6 causes the energization control execution circuit 7 (specifically, each phase winding switch means SWap, SWan, SWbp, SWbn, SWcp, SWcn) so that the waveform X1 ′ ”is substantially the same as the waveform X1”. Is controlled by the duty ratio.

  Similarly, when switching the winding group from “parallel connection to series connection”, if the torque waveform immediately before switching is the waveform X2 in FIG. 5, the torque immediately after switching the winding group from “parallel connection to series connection” The energization control command unit 6 controls the energization control execution circuit 7 (specifically, each phase winding switch means SWap, SWan, SWbp, SWbn, SWcp so that the waveform becomes “waveform X2 ′ substantially the same as the waveform X2”. , SWcn) is controlled by the duty ratio.

Further, the energization control command unit 6 will be specifically described.
The energization control command unit 6 of this embodiment switches the control parameter of the duty ratio according to the switching state (series connection or parallel connection) of the winding set, and applies the winding immediately before and after the switching of the winding set. By controlling the voltage average value to the turn ratio immediately before and after the switching, the torque waveforms immediately before and immediately after the switching of the winding group are made substantially the same waveform.

A specific example of this will be described with reference to FIGS.
When switching the winding set from “series connection to parallel connection”, the energization control command unit 6 switches the control parameter of the winding set from “series connection to parallel connection” (see step S13 in FIG. 4).
A specific example at this time is that when the duty ratio waveform of the A-phase winding switch means SWap and SWan immediately before switching the winding set from “series connection to parallel connection” is the waveform Y1 in FIG. The duty ratio waveform immediately after switching from "serial connection to parallel connection" is switched to the waveform Y1 'in FIG.

  As a result, when the average value of the applied coil voltage immediately before switching the winding group from “series connection to parallel connection” is the waveform Z1 in FIG. 5, the average applied coil voltage immediately after switching from “series connection to parallel connection” The value is set to a waveform Z1 ′ that is ½ times the turn ratio, and “torque waveform X1 immediately before switching” and “torque waveform X1 ′ immediately after switching” of the winding set are made substantially the same waveform.

Conversely, when switching the winding set from “parallel connection to series connection”, the energization control command unit 6 switches the control parameter of the winding set from “parallel connection to series connection” (see step S12 in FIG. 4).
A specific example at this time is that when the duty ratio waveform of the A-phase winding switch means SWap and SWan immediately before switching the winding group from “parallel connection to series connection” is the waveform Y2 in FIG. The duty ratio waveform immediately after switching from "parallel connection to series connection" is switched to the waveform Y2 'in FIG.

  Thus, when the average value of the applied coil voltage immediately before switching the winding group from “parallel connection to series connection” is the waveform Z2 in FIG. 5, the average applied coil voltage immediately after switching from “parallel connection to series connection”. The value is set to a waveform Z2 ′ that is twice the turn ratio, and “torque waveform X2 immediately before switching” and “torque waveform X2 ′ immediately after switching” of the winding set are made to be substantially the same waveform.

(Effect of Example 1)
As described above, the rotational force generator of this embodiment is as follows.
(I) Using the “torque T” of the SR motor 1 and the “rotational speed N” of the SR motor 1, switching of winding sets in each phase winding (“series connection → parallel connection”, “parallel connection → series connection”) )
(Ii) Switch the winding set ("series connection → parallel connection", "parallel connection → series connection") at the timing when the energization state of the phase winding is not energized,
(Iii) Further, by controlling the current waveform of the phase winding, the torque waveforms immediately before and immediately after the switching of the winding group are made substantially the same waveform.

This
(I) While being able to obtain a high output from the SR motor 1 in a wide operation range from a low rotation range to a high rotation range,
(Ii) Torque fluctuation caused by switching the winding group during energization of the phase winding can be avoided,
(Iii) Further, it is possible to avoid the torque fluctuation due to the change of the inductance of the winding set by switching the winding set.

[Example 2]
A second embodiment will be described with reference to FIG. In the following embodiments, the same reference numerals as those in the first embodiment denote the same functional objects.
In the first switching command unit 3 of the first embodiment, as shown in FIG. 2, the “required torque T” required by the ECU for the SR motor 1 and the “rotation speed N” of the SR motor 1 are used. An example of determining the optimum switching state (series connection or parallel connection) was shown.

On the other hand, the control circuit 2 of the second embodiment uses the “current value I” supplied to the SR motor 1 and the “rotation angle θ (or rotation speed N)” of the SR motor 1 to “output” of the SR motor 1. The torque estimation unit 17 for estimating the “torque T” is provided, and the first switching command unit 3 uses the estimated “output torque T” and the “rotational speed N” of the SR motor 1 to The optimum switching state (series connection or parallel connection) is determined.
Even if it provides in this way, the effect similar to the said Example 1 can be acquired.

[Example 3]
Embodiment 3 will be described with reference to FIG.
In this embodiment, windings (for example, the first A winding 1A and the second A winding 2A) forming a set in the same phase winding (for example, the A phase winding) are wound around the same stator tooth 13. Is.

Specifically, in FIG. 7, the first A winding 1 </ b> A and the second A winding 2 </ b> A in the A-phase winding are provided in the same stator tooth 13. Although not shown in FIG. 7, the first B winding 1B and the second B winding 2B in the B phase winding are provided in the same stator teeth 13, and the first C winding 1C and the second C winding in the C phase winding. 2C is also provided on the same stator teeth 13.
Even if it provides in this way, the effect similar to the said Example 1 can be acquired.

[Example 4]
Embodiment 4 will be described with reference to FIG.
In each of the above-described embodiments, as an example of switching the winding group, an example in which the connection state of the winding is switched to one of “series connection or parallel connection” has been described.
In contrast, in this embodiment, a part of the winding is provided so as to be detachable, and the connection state of the winding is “series connection or single connection (connection state in which only one winding of the winding set is energized)”. One of these is provided so as to be switchable.

Specifically, as shown in FIG. 8B, the switching execution circuit 5 of this embodiment is
(I) The energization circuit of the A-phase winding (the first A winding 1A and the second A winding 2A) is provided with a first A changeover switch SWsa1 for disconnecting the second A winding 2A, and the second A winding 2A is bypassed. A second A changeover switch SWsa2 for supplying electricity is provided,
(Ii) In the energization circuit of the B-phase winding (the first B winding 1B and the second B winding 2B), the first B changeover switch SWsb1 for separating the second B winding 2B is provided, and the second B winding 2B is bypassed. A second B selector switch SWsb2 for supplying electricity is provided,
(Iii) In the energization circuit of the C-phase winding (the first C winding 1C and the second C winding 2C), the first C changeover switch SWsc1 for separating the second C winding 2C is provided, and the second C winding 2C is bypassed. A second C changeover switch SWsc2 for supplying electricity is provided.

  Then, the first switching command unit 3 decides to switch each winding set to either “series connection” or “single connection” based on the “torque T” of the SR motor 1 and the “rotational speed N” of the SR motor 1. I do.

The second switching command unit 4
(I) At the timing of switching from “parallel connection to series connection” in the first embodiment, the switching execution circuit 5 of this embodiment (first A switch SWsa1, second A switch SWsa2, first B switch SWsb1, second B switch) The switch SWsb2, the first C changeover switch SWsc1, and the second C changeover switch SWsc2) are controlled to achieve “single connection → series connection”
(Ii) The switching execution circuit 5 (first A changeover switch SWsa1, second A changeover switch SWsa2, first B changeover switch SWsb1, second B changeover in this embodiment at the timing of switching from “series connection to parallel connection” in the first embodiment. The switching control of the switch SWsb2, the first C changeover switch SWsc1, and the second C changeover switch SWsc2) is performed to achieve “series connection → single connection”.
Even if it provides in this way, the effect similar to the said Example 1 can be acquired.

In the above embodiment, an example in which the present invention is applied to a rotational force generating device for driving a vehicle has been described. However, the present invention is not limited to driving a vehicle, and is a refrigerant compressor for an air conditioner mounted on an electric vehicle or the like. The present invention may be applied to other rotational force generators that are mounted on vehicles and generate rotational force, such as rotational force generators that drive (compressors).
Of course, the present invention is not limited to vehicles, and the present invention may be applied to various types of rotational force generators mounted on industrial equipment, household equipment, and the like.

  In the above embodiment, an example in which the present invention is applied to an inner rotor type electric motor (SR motor 1 in the embodiment) has been shown. However, an outer rotor type electric motor or a rotor core 12 is arranged in the axial direction of the stator core 11. The present invention may be applied to a type of electric motor.

The specific numerical values disclosed in the above embodiment (the number of phases of the phase winding, the number of stator teeth 13, the number of rotor teeth 15, etc.) are specific examples for explaining the embodiment and can be changed as appropriate. It is a thing.
In the above embodiment, the example in which the present invention is applied to the SR motor 1 is shown as an example of the electric motor. However, the present invention is not limited thereto, and the present invention may be applied to the stepping motor 1 ′ shown in FIG. .

1 SR motor (electric motor)
1 'Stepping motor (electric motor)
2 control circuit 3 first switching command unit 4 second switching command unit 5 switching execution circuit 6 energization control command unit 1A 1A winding 2A 2A winding 1B 1B winding 2B 2B winding 1C 1C winding 2C 2C winding

Claims (6)

An electric motor (1) equipped with a phase winding composed of a winding set capable of switching the connection state of the winding;
A control circuit (2) for switching the winding group according to the operating state;
In the rotational force generator comprising:
The control circuit (2) includes an energization control command unit (6) for controlling the current waveform of the phase winding so that the torque waveforms immediately before and after the switching of the winding group are substantially the same waveform. A rotational force generating device. In the rotational force generator of Claim 1,
The energization control command unit (6) controls the average value of the applied voltage immediately before and after the switching of the winding set to the turn ratio immediately before and after the switching. In the rotational force generator of Claim 1 or Claim 2,
The control circuit (2)
(A) a first switching command unit (3) that determines a switching state of the winding group based on an operating state;
(B) When the first switching command unit (3) determines to switch the winding group, a second switching that generates a switching instruction for the winding group at a timing when the energization state of the phase winding is not energized. Command section (4);
(C) a switching execution circuit (5) for switching the winding group based on the switching command of the second switching command unit (4);
A rotational force generating device comprising: In the torque generator of Claim 3,
The first switching command unit (3)
Torque (T) of the electric motor (1);
The number of revolutions (N) per unit time of the electric motor (1);
And determining a switching state of the winding group. In the rotational force generator of Claim 3 or Claim 4,
The second switching command unit (4)
A determination state of the first switching command section (3);
Switching state of the current winding set;
The current value (I) of the phase winding;
A torque generating device characterized by generating a switching instruction using the In the rotational force generator in any one of Claims 1-5,
The energization control command section (6) switches a control parameter in accordance with the switching of the winding group, and the rotational force generator.

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