JP2020043740A - Motor generator control device - Google Patents

Abstract

To realize smooth winding switching with an inexpensive and simple structure.SOLUTION: There is provided a control device of a motor generator 3. An inverter 32 drives and controls a motor 30 by supplying alternating currents having different phases to three different winding groups 50. A switching mechanism 31 is connected between the motor 30 and the inverter 32. A PCM 5 controls the inverter 32 and the switching mechanism 31 on the basis of a signal input from the PCM 5. The switching mechanism unit 31 switches the connection state of the winding group 50 between the series winding state and the parallel winding state. The switching mechanism 31 includes a relay 70, and at least one of the plurality of contacts is configured by a mechanical contact of the relay 70.SELECTED DRAWING: Figure 6

Description

  The disclosed technology relates to a control device for a motor generator that is suitable for a hybrid vehicle, an electric vehicle, and the like and can be used for both a motor and a generator.

  When an electric motor is used as a drive source of an automobile, a wide range of driving force is required in both torque and rotation speed. For example, at a low speed such as at the time of starting, a high torque is required because the engine is used for starting and starting the engine. On the other hand, when driving at high speeds on flat ground or downhill, high torque is not required, but high rotation is required. In addition, in the above-described hybrid vehicles and the like, generally, the electric motor is often used not only as a drive source but also as a generator that recovers kinetic energy as electric energy during braking.

  In such a motor of a motor generator (usually a permanent magnet synchronous motor), if the number of windings (stator coils) is large, a strong magnetic force can be generated, which is advantageous for high torque. However, since the back electromotive force increases, it is disadvantageous for high rotation. On the other hand, if the number of turns is small, the back electromotive force is small, which is advantageous for high rotation, but the output torque is small. Therefore, it is disadvantageous for high torque. That is, it is difficult for the motor itself to realize a wide driving force required by an automobile.

  Therefore, a technique has been proposed in which a wide driving force is realized by switching the connection state of the windings of the motor (for example, Patent Documents 1 and 2).

  Patent Document 1 discloses a winding switching device that electrically switches a connection state of windings of a three-phase AC motor. The winding switching device includes a winding switching unit having an electric circuit including a semiconductor switch, a diode, a capacitor, and the like. The winding switching unit is connected to the other end of each phase winding, one end of which is connected to the inverter, and to an intermediate point of each phase winding.

  When the semiconductor switch is turned on and off, the winding switching unit switches between a state in which the former is electrically connected (first connection state) and a state in which the latter is electrically connected (second connection state). Switch. In the first connection state, current is supplied to all windings of each phase, which is advantageous for low-speed and high-torque operation. In the second connection state, half of each phase winding is energized, which is advantageous for high-speed and low-torque operation.

  Patent Document 2 discloses a winding switching device that mechanically switches a connection state of windings of a three-phase AC motor. The winding switching device includes a device main body electrically connected to the inverter and the three-phase AC motor, a movable body slidably accommodated in the device main body, and a driving device for sliding the movable body. It is configured.

  The wiring corresponding to each phase is provided inside the movable body. When the movable body is slid by the driving device, the connection state of the windings of each phase is switched between a series state and a parallel state.

JP 2009-225617 A JP-A-2017-70112

  As in the winding switching device of Patent Literature 1, if a short circuit is made at the intermediate point between the windings of each phase in order to establish a connection state that is advantageous at high speed, the remaining windings are not used. Therefore, the winding is wasted and the efficiency is reduced. Therefore, in order to eliminate such a decrease in efficiency and waste of windings, the winding switching device disclosed in Patent Document 1 and the winding switching device disclosed in Patent Document 2 also use the remaining windings. May be connected in parallel.

  However, in order to switch to such a connection state by the winding switching unit, an electric circuit becomes complicated and a large number of electronic components are required. As a result, the size of the winding switching unit is increased, and the material cost is increased.

  In that regard, the winding switching device of Patent Document 2 that mechanically switches can switch the winding of each phase between the series state and the parallel state at relatively low cost.

  However, the winding switching device of Patent Literature 2 has a complicated structure, and it is necessary to stack switching wires of each phase in the sliding direction at intervals, so that a certain size is required. Therefore, the installation place is limited. Further, in the winding switching device of Patent Literature 2, it is necessary to slide the movable body with high accuracy by the driving device at the time of switching the winding, and to stably secure the electrical connection of the contacts. Therefore, there is room for improvement in terms of responsiveness and stability.

  Further, when the winding is mechanically switched as in the winding switching device of Patent Literature 2, due to a structural difference, compared to the case of electrically switching as in the winding switching device of Patent Literature 1, Switching takes time. Therefore, at the time of switching, the torque output by the motor (output torque) becomes discontinuous, and a torque shock is likely to occur. Further, when switching between the serial state and the parallel state, a torque shock is also generated due to a difference in output torque in each state.

  Therefore, the disclosed technology is to realize smooth switching of windings with an inexpensive and simple structure so that the motor generator can stably respond to a wide range of driving force required by an automobile. Is the main purpose.

  The disclosed technology relates to a control device for a motor generator.

  The control device is a motor provided with a plurality of different winding groups, a measuring unit that detects the operating state of the motor, and supplies each of the winding groups to the motor by supplying an alternating current having a different phase. An inverter for drive control, a switching mechanism connected between the motor and the inverter, and a controller for controlling the inverter and the switching mechanism based on a signal input from the measuring unit. Prepare.

  Each of the winding groups is composed of a plurality of winding elements. The switching mechanism opens and closes between a series winding state in which the winding elements are connected in series and a parallel winding state in which the winding elements are connected in parallel according to an operation state of the motor. A plurality of contacts for switching the connection state of each of the winding groups. The switching mechanism includes a relay, and at least one of the plurality of contacts is configured by a mechanical contact of the relay.

  According to this control device, each of the winding groups of the motor is configured by a plurality of winding elements, and the switching mechanism unit is configured to connect the winding elements in series according to the operation state of the motor. The connection state is switched between a state and a parallel winding state in which the winding elements are connected in parallel. Therefore, by switching the winding state while efficiently using the winding provided in the motor, the motor performance can be expanded over a wide range of torque and rotation speed. As a result, the motor generator can stably cope with a wide range of driving force required by an automobile.

  The switching mechanism includes a relay, and at least one of the plurality of contacts that switches the winding state by opening and closing is configured by a mechanical contact of the relay. Therefore, a complicated electronic circuit using a large number of electronic components and a complicated mechanical structure can be avoided, and a smooth and easy switching of windings can be realized with an inexpensive and simple structure.

  The control device is also configured such that the plurality of contacts include three mechanical contacts that switch each of the winding groups to one of the series winding state and the parallel winding state, and the relay includes: A plurality of terminals comprising a fixed terminal and a movable terminal, constituting the three mechanical contacts, a movable section supporting the movable terminal, and one action section for operating the movable section under the control of the control section; And the open / closed state of the three mechanical contacts may be simultaneously switched by the operating unit operating the movable unit.

  Then, just by operating the operating part, the open / close state of the three mechanical contacts is switched at the same time, so the switching mechanism is realized with a cheaper and simpler structure than the electric contacts using semiconductor switches etc. it can.

  In addition, since each winding group is configured to be switched to one of a series winding state and a parallel winding state by one operation, it is ensured that one of the series winding state and the parallel winding state is switched to the other. Can switch. Therefore, control stability is also excellent.

  The control device may be configured such that the control unit controls the inverter such that an alternating current flowing through the mechanical contact becomes substantially zero at a timing when the mechanical contact is opened and closed.

  When switching a mechanical contact, if the mechanical contact is opened and closed while a current is flowing through the contact, the mechanical contact may be damaged due to an overcurrent or the like. Also, in the case of a mechanical contact, unlike an electrical contact that can be instantaneously switched, it takes time to switch.

  As a result, no power is supplied to the motor during that time, and the torque output by the motor becomes zero (a zero torque period occurs). As a result, the output torque becomes discontinuous, and a torque shock may occur.

  On the other hand, if the inverter is controlled so that the alternating current flowing through the mechanical contacts becomes substantially zero at the timing when the mechanical contacts are opened and closed, the mechanical contacts are opened and closed because the current is substantially zero. Even so, the damage can be avoided. Then, the time for switching the mechanical contacts is secured, and even if the output torque becomes discontinuous, the effect can be suppressed, so that the torque shock can also be suppressed.

  The control device may further include three contacts that switch each of the winding groups to one of the series winding state and the parallel winding state, and the switching mechanism unit may include an electrical switch. An electronic changeover switch formed of a circuit may be further included, and the three contacts may be constituted by a mechanical contact of the relay and an electric contact of the electronic changeover switch.

  Also in this case, since a part of the contact of the switching mechanism is constituted by the mechanical contact of the relay, a complicated electronic circuit using a large number of electronic components and a complicated mechanical structure can be avoided, and it is inexpensive and With a simple structure, smooth switching of windings can be realized.

  In addition, in this case, although the details will be described later, by arranging the mechanical contacts and the electrical contacts in a predetermined arrangement, it is possible to continuously switch the winding state without generating a zero torque period even when the motor is energized. Becomes possible. Also, there is an advantage that the driving of the motor can be stably maintained even if the relay is damaged.

  The control device is also configured such that the control unit, at a timing at which the mechanical contact is opened and closed, supplies a correction current through the electronic changeover switch, so that the control unit corresponds to the mechanical contact and the electronic changeover switch. The switching mechanism and the inverter may be controlled so that the alternating current flowing through the winding group is corrected.

  The torque constant of the motor changes with the switching of the winding state. Therefore, even if the switching can be performed continuously, a torque shock occurs due to a change in the torque constant. On the other hand, in this case, at the time of switching transition, the correction current can be supplied to the winding group through the electronic changeover switch, so that the fluctuation of the output torque can be suppressed by the correction current.

  According to the disclosed technology, smooth switching of windings can be realized with an inexpensive and simple structure, so that the motor generator can stably cope with a wide range of driving force required by an automobile. .

It is the schematic which shows the principal part of the vehicle to which the technique disclosed is applied. FIG. 2 is a block diagram illustrating a main configuration of a control device. It is a schematic diagram which shows the structure of a motor and a switching mechanism part. It is the schematic which shows the winding structure of a stator. It is the schematic which shows a series winding state. It is the schematic which shows a parallel winding state. It is a figure which shows the motor characteristic in each case of a series winding state and a parallel winding state. It is the schematic which shows the structure of a switching mechanism part. It is an example of switching control of a winding state. It is a figure which shows an example of the phase current at the time of switching of a winding state (switching from a series winding state to a parallel winding state) during motor energization. It is an example of the switching control corresponding to FIG. It is the schematic which shows the structure of the switching mechanism part in the control apparatus of an application example. FIG. 13 is a diagram illustrating an example of a phase current in a switching control of a winding state (switching from a series winding state to a parallel winding state) during energization of a motor in a control device of an application example. It is an example of the switching control corresponding to FIG. FIG. 14 is a diagram illustrating an example of a phase current in a switching control of a winding state (switching from a parallel winding state to a series winding state) during energization of a motor in a control device of an application example. 14 is an example of switching control corresponding to FIG. 13.

  Hereinafter, embodiments of the disclosed technology will be described in detail with reference to the drawings. However, the following description is merely an example in nature, and does not limit the present invention, its application, or its use.

<In-vehicle example>
FIG. 1 shows a vehicle 1 to which the disclosed technology is applied. The example vehicle 1 is a so-called hybrid vehicle. The vehicle 1 includes an engine 2, a motor generator 3, a low-voltage power supply 4, a PCM 5 (an example of a control unit), and the like. The motor generator 3 includes a motor 30, a switching mechanism 31, an inverter 32, and the like. The control device for controlling the motor generator 3 is configured to include the PCM 5 and sensors 9a to 9d to be described later, in addition to the devices 30, 31, and 32.

  The engine 2 is a known internal combustion engine that generates power for the vehicle 1 by burning fuel. The engine 2 is provided with a fuel tank, an intake / exhaust system, and the like (these are publicly known and are not shown). The crankshaft 2 a of the engine 2 is connected to the rotating shaft 30 a of the motor 30 in series with the clutch 6 via the clutch 6. The rotating shaft 30a of the motor 30 is connected to driving wheels 1a of the vehicle 1 via a transmission 7, a differential gear 8, and the like. The transmission 7 also functions as a clutch.

  By driving the engine 2 in a state where the clutch 6 is connected, the vehicle 1 can run by burning fuel, similarly to a normal vehicle. In addition, by driving the motor 30 in a state where the clutch 6 is disengaged, the vehicle can run electrically. Further, by driving the engine 2 and the motor 30 with the clutch 6 connected, the vehicle 1 can run with both fuel combustion and electric power.

  Further, when the vehicle 1 is braked, for example, by disengaging the clutch 6, the motor 30 can be rotated by the rotational force of the drive wheel 1a. Thereby, the motor 30 can be made to function as a generator, and the kinetic energy can be recovered to the low-voltage power supply 4 as electric energy. The vehicle 1 is a so-called parallel hybrid vehicle.

  The low voltage power supply 4 is a DC power supply. A specific example of the low-voltage power supply 4 is, for example, a rechargeable secondary battery, and a relatively low voltage (rated voltage) of 48 V is used. In addition, the vehicle 1 is provided with a battery having a rated voltage of 12 V in addition to the low-voltage power supply 4 in order to supply electric power to the mounted electric components (not shown).

  The low-voltage power supply 4 is electrically connected to the motor 30 via an inverter 32 and a switching mechanism 31 (hereinafter, simply referred to as connection). The inverter 32 is a device that converts DC power into AC power and outputs the converted power (it is a known device, so the details are omitted). The inverter 32 converts the DC power input from the low-voltage power supply 4 into three-phase AC power having different phases (so-called U-phase, V-phase, and W-phase) based on a control signal input from the PCM 5. And outputs it to the motor 30. The inverter 32 controls the driving of the motor 30 by supplying the three-phase AC power to the motor 30.

  The switching mechanism 31 is connected so as to be interposed between the motor 30 and the inverter 32. The switching mechanism 31 may be functionally interposed between the motor 30 and the inverter 32, but the switching mechanism 31 of this embodiment is provided integrally with the motor 30. By providing the motor 30 and the switching mechanism 31 integrally, there is an advantage that the wiring can be simplified and the structure of the control device can be simplified as described later. On the other hand, by arranging the switching mechanism section 31 separately from the motor 30, the influence of heat generation of the motor 30 can be suppressed, so that there is an advantage that the heat resistance required for the switching mechanism section 31 can be reduced.

  The PCM 5 (power train control module) is a device that comprehensively controls the operation of the vehicle 1 such as controlling the driving of the engine 2 and the motor 30. The PCM 5 is a controller based on a known microcomputer. As shown in FIG. 2, the PCM 5 includes a CPU 5a that executes a program, a memory 5b that includes a RAM and a ROM and stores programs and data, An input / output bus 5c (I / O bus) for inputting and outputting signals.

  Various sensors (an example of a measurement unit) that detect the operation states of the engine 2 and the motor 30 are connected to the PCM 5. For example, a water temperature sensor 9a (a sensor attached to the engine 2 and measuring the temperature of the cooling water), a crank angle sensor 9b (a sensor attached to the engine 2 and measuring a rotation angle of the crankshaft 2a), an accelerator opening A degree sensor 9c (a sensor attached to the accelerator pedal mechanism of the vehicle 1 and measuring an accelerator opening corresponding to the operation amount of the accelerator pedal), a motor sensor 9d (attached to the motor 30 and detects the rotation angle of the rotation shaft 30a). Sensor for measurement) is connected. While the vehicle 1 is operating, the detection signals output from these sensors are always input to the PCM 5. Further, the inverter 32 is provided with an ammeter for measuring a current value flowing through the inverter 32. The signal output from the ammeter is also always input to the PCM 5 (an ammeter is also an example of a measuring unit).

  The PCM 5 is connected to the inverter 32 and the switching mechanism 31 together with the engine 2. The PCM 5 outputs control signals to the inverter 32 and the switching mechanism 31 based on the detection signals input from the above-described sensors 9a to 9d and the like to control them. Thereby, the drive of the motor 30 is controlled in accordance with the driving state of the vehicle 1.

(Motor 30)
FIG. 3A schematically shows the motor 30 and the switching mechanism unit 31. The motor 30 of the present embodiment is a so-called permanent magnet synchronous motor. The motor 30 has a stator 30b and a rotor 30c. The rotor 30c is provided integrally with the rotating shaft 30a. A plurality of permanent magnets 30d are arranged at equal intervals over the entire circumference of the rotor 30c. These permanent magnets 30d are arranged so that N poles and S poles are alternately arranged in each of the circumferential direction and the radial direction, and constitute the magnetic poles of the rotor 30c.

  The stator 30b is formed in a substantially cylindrical shape, and is arranged around the rotor 30c such that the inner peripheral surface thereof faces the outer peripheral surface of the rotor 30c with a slight gap. The stator 30b has a stator core 30e made of a magnetic material and a plurality of coils 30f. In the stator core 30e, a plurality of slots are arranged at equal intervals over the entire circumference. The coil 30f is configured by winding a covered electric wire in a predetermined order through these slots.

  Thereby, as shown in FIG. 3B, the stator 30b is provided with three different winding groups 50 including a U-phase group, a V-phase group, and a W-phase group. These winding groups 50 are connected to each other at a neutral point 51 (so-called Y connection or star connection). Each of the winding groups 50 has two winding elements (a first winding element 50a and a second winding element 50b) having substantially the same number of turns, and connects these winding elements 50a and 50b in series. It is configured. Alternating current is supplied to the winding group 50 of each phase from the inverter 32 through each input terminal in a different phase.

(Switching mechanism section 31)
The switching mechanism 31 has a function of switching the connection state of the winding groups 50 so that a wide range of driving force suitable for driving the vehicle 1 can be obtained from the output from the motor 30.

  Specifically, as shown in FIGS. 4A and 4B, the switching mechanism unit 31 includes three contacts for each of the winding groups 50 of the U-phase group, the V-phase group, and the W-phase group. It has a first switch 61 and a second switch 62. The first switch 61 is arranged between the first winding element 50a and the second winding element 50b. The winding group 50 of each phase has a first bypass wiring 63 that bypasses the first winding element 50a, and the first switch 61 is configured to be connectable to the first bypass wiring 63 as well.

  The winding group 50 of each phase also includes a portion between the first winding element 50a and the second switch 62 so as to bypass the first switch 61 and the second winding element 50b, and a neutral point. There is a second bypass wiring 64 connecting between the first bypass wiring 51 and the second bypass wiring 51. The second switch 62 is arranged on the second bypass wiring 64. The structure of the winding group 50 of each phase is the same. Therefore, in these figures, only the U-phase group shows a specific structure, and the structures of the V-phase group and the W-phase group are omitted (the U-phase group will be described below as an example).

  By setting the two switches 61 and 62 in the winding group 50 of each phase to a predetermined state, the switching mechanism unit 31 switches two windings as shown in FIG. Either a state where the elements 50a and 50b are connected in series (series winding state) or a state where two winding elements 50a and 50b are connected in parallel (parallel winding state) as shown in FIG. 4B. On the other hand, the connection state of each of the U-phase, V-phase, and W-phase winding groups 50 is switched.

  As shown in FIG. 4A, when the connection state of the winding groups 50 of each phase is a series winding state, the supplied AC power is in the same state as the number of turns of the coil 30f is substantially increased. (Inductance increases). As a result, the flux linkage between the winding group 50 and the magnet generated when the current is supplied to the winding group 50 increases, so that a high torque can be obtained.

  On the other hand, as the number of turns increases, strong back electromotive force is generated between the rotating rotor 30c and the permanent magnet 30d by electromagnetic induction. As a result, the supply voltage substantially decreases as the rotational speed increases, so that the drivable rotational speed decreases. In addition, since the generation of the strong back electromotive force increases the current for weakening the magnetic flux, even when the engine 2 is driven, high efficiency cannot be obtained when the rotation speed becomes high.

  On the other hand, as shown in FIG. 4B, when the connection state of the winding groups 50 of each phase becomes a parallel winding state, the same state as the case where the number of turns of the coil 30f is substantially reduced with respect to the supplied AC power (Inductance decreases). As a result, the flux linkage between the magnets generated when the current is supplied to the winding group 50 is reduced, and the back electromotive force is suppressed accordingly. Will be possible. However, since the flux linkage with the magnet is reduced, high torque cannot be obtained.

  FIG. 5 illustrates an operation range of the motor 30 corresponding to the motor characteristics in each of the series winding state and the parallel winding state. The solid line indicates the operating region corresponding to the motor characteristics in the series winding state. A broken line indicates an operation region corresponding to the motor characteristics in the parallel winding state.

  In FIG. 5, the vertical axis represents the level of the torque due to the motor output, and the horizontal axis represents the level of the rotation speed due to the motor output. The upper side of the horizontal axis is the operating region of the motor 30 as the electric motor, that is, the region during power running, and the lower side of the horizontal axis is the operating region of the motor 30 as the generator, that is, the region during regeneration.

  In the series winding state, a relatively high torque T1 (T1 ') can be output at a low rotation speed, but can be output only up to a relatively low rotation speed R1. On the other hand, in the parallel winding state, it is possible to output up to a relatively high rotation speed R2, but even at low rotations, it can only output up to a relatively low torque T2 (T2 ').

  On the other hand, the motor generator 3 is configured so that either one of the series winding state and the parallel winding state can be selected and used. Therefore, both of these motor characteristics can be exhibited, and the output of the motor 30 can provide a wide range of driving force suitable for driving the vehicle 1 from low rotation high torque to high rotation low torque. I have.

(Specific structure of the switching mechanism 31)
In the control device of the present embodiment, the switching mechanism 31 includes a relay 70 (so-called relay), and the first switch 61 and the second switch 62 shown in FIG. . The relay 70 is configured to be interposed between the first winding element 50a and the second winding element 50b separated from each other and to connect them. In the configuration of the winding group 50, for convenience, the one having an input terminal is described as the upstream side, and the one having the neutral point 51 is described as the downstream side.

  FIG. 6 shows a specific example of the relay 70. The relay 70 includes an electromagnet 71, a rocking plate 72, a frame 73, a coil spring 74 (elastic member), a first fixed terminal 75, a second fixed terminal 76, a third fixed terminal 77, a first movable terminal 78, and a second movable terminal. 79 and the like. The electromagnet 71 is an example of an action section, and the swing plate 72, the frame 73, and the coil spring 74 are examples of a movable section.

  The first movable terminal 78, the first fixed terminal 75, and the third fixed terminal 77 constitute a first switch 61, and the second movable terminal 79 and the second fixed terminal 76 constitute a second switch 62. ing. The first movable terminal 78 is connected to the upstream side of the second winding element 50b. The first fixed terminal 75 is connected to the upstream side of the first winding element 50a via the first bypass wiring 63.

  The third fixed terminal 77 is connected to the downstream side of the first winding element 50a. The second movable terminal 79 is connected to the neutral point 51 via a part of the second bypass wiring 64. The second fixed terminal 76 is connected to the downstream side of the first winding element 50a via a part of the second bypass wiring 64.

  The main body of the swing plate 72 is made of an insulating member. A magnetic body (not shown) is attached to the lower surface of the oscillating plate 72 (on the side of the electromagnet 71). One end (base end) of the swing plate 72 is rotatably supported by the frame 73. The base end of the swinging plate 72 is urged by a coil spring 74 so that the other end (tip) is rotated upward in FIG.

  A first movable terminal 78 and a second movable terminal 79 are attached to a position away from the tip of the swing plate 72. The first fixed terminal 75 and the second fixed terminal 76 are arranged on the frame 73 so as to be in contact with the first movable terminal 78 and the second movable terminal 79 to prevent the swing plate 72 from rotating upward. ing. A first contact 81 is provided at a contact portion where the first fixed terminal 75 and the first movable terminal 78 contact each other.

  A second contact 82 is provided at a contact portion where the second fixed terminal 76 and the second movable terminal 79 contact each other. The third fixed terminal 77 is arranged below the first fixed terminal 75 so as to face the first fixed terminal 75.

  The electromagnet 71 is disposed below the rocking plate 72 so as to face the magnetic body. The electromagnet 71 is connected to the PCM 5. When the electromagnet 71 is energized based on the control of the PCM 5, a magnetic force is generated in the electromagnet 71. Thus, the swing plate 72 swings downward against the urging force of the coil spring 74. As a result, the first movable terminal 78 and the second movable terminal 79 are separated from the first fixed terminal 75 and the second fixed terminal 76, and the first movable terminal 78 contacts the third fixed terminal 77. A third contact 83 is provided at a contact portion where the first movable terminal 78 and the third fixed terminal 77 contact each other.

  That is, when the electromagnet 71 is energized, the open / close states of the first to third mechanical contacts 81, 82, 83 are simultaneously switched. As a result, the state is switched from the parallel winding state shown in FIG. 4B to the series winding state shown in FIG. 4A. The switching mechanism 31 is designed to be in a parallel winding state in a non-energized state (a so-called normal state). When the energization of the electromagnet 71 is stopped, the state is switched from the series winding state to the parallel winding state.

  As described above, by using the relay 70 exclusively for switching, which switches the open / close state of the three mechanical contacts 81, 82, 83 at the same time depending on the presence or absence of energization of one electromagnet 71, an electric system using a semiconductor switch or the like is used. The switching mechanism 31 can be realized with a simpler and cheaper structure than the contact.

  In addition, since each winding group 50 is configured to switch between the series winding state and the parallel winding state, it is possible to reliably switch between the series winding state and the parallel winding state. Excellent in control stability.

  Further, as shown in FIG. 3A, one wiring for supplying alternating current from the inverter 32 and the first and second switches 62 are provided between the switching mechanism 31 and the motor 30 for each winding group 50. A total of six wirings are provided, including two wirings to be controlled. On the other hand, in this control device, the switching mechanism 31 is provided integrally with the motor 30 as described above. Therefore, the wiring is simplified, and the structure of the control device is simplified.

(Example of switching control of winding state)
FIG. 7 shows an example of switching control of the winding state of the motor 30 by the PCM 5. The illustrated switching control shows a case where the vehicle 1 starts running from a stopped state, such as when the engine 2 is started.

  In the vehicle 1 according to the present embodiment, the motor 30 is driven mainly when the engine 2 is started, when the vehicle 1 starts, and when the vehicle 1 moves backward. When the vehicle 1 starts or reverses, the motor 30 is driven in a state where the driving by the engine 2 is assisted. Instead of using the engine 2, the motor 1 may start and reverse using the motor 30 alone.

  When the vehicle 1 is running, the engine 2 is normally driven. That is, the vehicle 1 runs mainly using the engine 2 as a drive source. When the vehicle 1 is running, the motor 30 assists the driving of the engine 2 as necessary, or is used as a generator during braking.

  As described above, the mechanical contacts 81, 82, and 83 of the switching mechanism 31 are designed to be in a parallel winding state when no current is supplied. In the parallel winding state, advantageous motor 30 characteristics can be exhibited at high speed. Therefore, even if the power supply to the motor 30 is interrupted due to some trouble, the vehicle 1 can be driven smoothly by driving the engine 2.

  When the operation of the vehicle 1 is started and the power is turned on, a detection signal is constantly input to the PCM 5 from the sensors 9a to 9d. When the vehicle 1 starts running from a stopped state, the PCM 5 controls information of a predetermined sensor such as a crank angle sensor 9b and an accelerator opening sensor 9c to control the switching of the winding state of the motor 30. Is read (step S1).

  The PCM 5 determines whether the temperature of the engine cooling water is lower than a predetermined reference temperature T based on the detection signal input from the water temperature sensor 9a (Step S2). That is, it is determined whether or not the engine 2 is sufficiently warmed (warm-up state). The reference temperature T is an arbitrary set value and is set in the memory 5b in advance.

  When the temperature of the engine cooling water is equal to or higher than the predetermined reference temperature T (No in step S2), the PCM 5 maintains the parallel winding state and returns. That is, the PCM 5 drives the motor 30 while keeping the winding groups 50 in the parallel winding state to start the engine 2, start the vehicle 1, or retreat the vehicle 1. Since the engine 2 is in a warm state, the motor 30 can start the engine 2 smoothly even in the parallel winding state where high torque cannot be obtained.

  As long as the temperature of the engine cooling water does not fall below the predetermined reference temperature T, the state of the parallel winding is maintained, so that the frequency of the switching control can be suppressed and efficient control can be performed.

  On the other hand, when the temperature of the engine cooling water is lower than the predetermined reference temperature T (Yes in step S2), the PCM 5 determines whether the engine 2 is driven based on the detection signal of the crank angle sensor 9b. (Step S3). If the engine 2 is being driven (No in step S3), the parallel winding state is maintained and the routine returns. Even if a high torque is not obtained, the vehicle 1 can be smoothly started and retreated in cooperation with the engine 2.

  When the engine 2 is not driven (Yes in step S3), each winding group 50 is switched to a series winding state (step S4). Since the motor 30 is not rotating, switching can be performed without any trouble.

  Then, the PCM 5 connects the clutch 6 and starts the engine 2 by the motor 30 (step S5). Since the motor 30 is in a series winding state in which a high torque can be generated, even if the engine 2 is cold, the engine 2 can be started stably.

  Then, the PCM 5 determines whether the rotation speed of the motor 30 is in a predetermined low rotation range based on the detection signal of the motor sensor 9d (Step S6). The low rotation region may be a low rotation region when the rotation region in which the motor 30 can operate is bisected. In addition, the low rotation region may be the region on the lowest rotation side when the rotation region in which the motor 30 can be operated is divided into three equal parts.

  Then, when the rotation speed of the motor 30 reaches a predetermined low rotation region (Yes in step S6), the PCM 5 switches each winding group 50 to a parallel winding state (step S7). That is, when the engine 2 starts and reaches a certain number of revolutions, the state is immediately switched to the parallel winding state.

  The winding state of the motor 30 is mainly used in a parallel winding state, and the series winding state is used mainly in a limited state such as starting the engine 2. Further, when the motor 30 is used as a generator, the parallel winding state is used regardless of the rotation speed. Thereby, the frequency of switching the winding state is suppressed.

  By performing such infrequent switching of the winding state in the low rotation region, as will be described below, it occurs when the winding state is switched when the current is flowing through the motor 30. The effect of the zero torque period can be suppressed.

(Switch the winding state while the motor is energized)
When switching a mechanical contact, if the mechanical contact is opened and closed while a current is flowing through the contact, the mechanical contact may be damaged due to an overcurrent or the like. Also, in the case of a mechanical contact, unlike an electrical contact that can be instantaneously switched, it takes time to switch.

  As a result, no power is supplied to the motor 30 during that time, and the torque output by the motor 30 becomes zero. That is, a zero torque period occurs. As a result, the output torque becomes discontinuous, and there is a possibility that a torque shock giving an uncomfortable feeling to the running of the vehicle 1 may occur.

  Therefore, in this control device, control for switching the winding state during energization of the motor 30 is devised so that such a problem can be suppressed. Specifically, at the timing when the mechanical contacts 81, 82, 83 are opened and closed, the PCM 5 controls the inverter 32 so that the AC flowing through the mechanical contacts 81, 82, 83 becomes substantially zero. That is, the mechanical contacts 81, 82, 83 of the winding group 50 are switched at the timing when the phase current flowing through the winding group 50 of each phase becomes zero cross.

  FIG. 8 shows an example of the phase current when the winding state is switched while the motor is energized (switching from the series winding state to the parallel winding state). FIG. 9 shows an example of the switching control. Since the phase current is an alternating current, the timing at which the current flowing through the winding group 50 becomes zero or zero crossing occurs periodically. Here, the switching from the series winding state to the parallel winding state is illustrated, but the reverse of the switching from the parallel winding state to the series winding state can be switched in the same manner. it can.

  When the number of rotations of the motor 30 reaches a predetermined low rotation region and there is a request to switch the winding state (Yes in step S10), the PCM 5 is configured based on the detection signal input from the ammeter of the inverter 32. Then, the timing at which the phase current flowing through the winding group 50 to be switched becomes zero crossing is determined (step S11).

  Then, the PCM 5 controls the inverter 32 at a timing at or near zero crossing where the phase current flowing through the winding group 50 to be switched becomes substantially zero, and reduces the current for a predetermined period (for example, several ms). It is maintained at zero (step S12). By doing so, the period t0 (non-energized period) shown in FIG. 8 is secured.

  The PCM 5 controls the switching mechanism 31 to open and close the mechanical contacts 81, 82, and 83 to switch the winding state during the non-energization period (step S13). If the timing is at or near zero crossing, the current flowing through the winding group 50 is substantially zero, so that the current can be smoothly reduced to zero. Since the current is substantially zero, the time for switching the mechanical contacts 81, 82, 83 is secured, and even if the output torque becomes discontinuous, the effect can be suppressed.

  Furthermore, the torque constant differs between the series winding state and the parallel winding state. Therefore, as shown by the phantom line in FIG. 8, when switching to the parallel winding state with the same current value as the series winding state, a difference occurs in the output torque. That is, a torque shock may occur.

  Therefore, the PCM 5 controls the inverter 32 according to the difference between the torque constants during the non-energization period, and adjusts the magnitude of the phase current as shown by the solid line in FIG. 8 (step S14). As a result, the output torque becomes substantially constant before and after the switching, and the torque shock caused by the difference in the torque constant can be suppressed.

  When the rotational speed is high, the zero torque period becomes relatively long, and thus the rotational speed is easily affected by torque shock. On the other hand, in this control device, as described above, switching is performed in a state where the number of rotations is low, so that the influence of torque shock can be suppressed.

(Application example)
In the above-described embodiment, the control device in which the contacts 81, 82, and 83 of the switching mechanism unit 31 are all configured by mechanical contacts by using the relay 70 dedicated to switching has been exemplified. In this application example, an electronic changeover switch 100 formed of an electric circuit is used together with the relay 70, and a control device in which the contacts of the changeover mechanism 31 are used in combination with mechanical contacts and electric contacts is exemplified. Note that this application example will be described as being applied to the same vehicle 1 as the above-described embodiment. Therefore, description of the same configuration and members will be omitted, and different contents will be specifically described.

  FIG. 10 shows a specific example of the switching mechanism unit 31 of the control device corresponding to FIG. As described above, the switching mechanism unit 31 includes the first switch 61 and the second switch 62 for each of the winding groups 50 of the U-phase group, the V-phase group, and the W-phase group. In the switching mechanism 31, the first switch 61 is configured by a relay 70 ', and the second switch 62 is configured by an electronic changeover switch 100.

  The electronic changeover switch 100 is configured by an electric circuit in which a diode bridge, a semiconductor switch, a diode, and the like are arranged. Since the electronic changeover switch 100 has a known structure, a specific description thereof is omitted.

  The relay 70 ′ has the same basic structure as the relay 70 of the above-described embodiment, but differs from the relay 70 of the above-described embodiment in that the relay 70 ′ does not include the second movable terminal 79 and the second fixed terminal 76. That is, in this control device, the first contact 81 and the third contact 83 are constituted by mechanical contacts, and the second contact 82 is constituted by electric contacts.

  According to the switching mechanism 31, since the mechanical relay 70 'having a simple structure and the conventional electronic changeover switch 100 can be configured, even if the electronic changeover switch 100 is used, the structure can be prevented from becoming complicated. And it can be realized inexpensively and compactly.

  Furthermore, according to the switching mechanism unit 31 having such a structure, the winding state can be switched continuously without generating a zero torque period even when the motor 30 is energized. The control device is devised so as to suppress torque shock at the time of switching the winding state.

  Specifically, the PCM 5 supplies a correction current through the electronic changeover switch 100 at a timing when the mechanical contact is opened and closed. By doing so, the switching mechanism 31 and the inverter 32 are controlled so that the alternating current flowing through the winding group 50 to be switched is corrected.

  When switching from the series winding state to the parallel winding state, the PCM 5 switches the winding state while continuously outputting torque at any timing, not only at the timing of zero crossing. When switching from the parallel winding state to the series winding state, the PCM 5 switches the winding state while continuously outputting torque at the timing of zero crossing.

(Switch from series winding state to parallel winding state)
FIG. 11 shows an example of the phase current in the switching control of the winding state during the energization of the motor (switching from the series winding state to the parallel winding state). FIG. 12 shows an example of the switching control.

  When the number of rotations of the motor 30 reaches a predetermined low rotation region and there is a request to switch the winding state (Yes in step S20), the PCM 5 controls the switching mechanism unit 31 to The switch is turned on (step S21). This timing is an arbitrary timing that is not limited to the timing of the zero cross. In FIG. 11, the switch of the electronic changeover switch 100 is turned on at a point P1.

  Thereby, as shown in the schematic diagram on the left side shown by the broken line in FIG. 11, the second switch 62 changes from the open state to the closed state, and the second winding element 50b is connected in parallel with the second bypass wiring 64. Becomes Since the torque constant changes accordingly, the PCM 5 controls the inverter 32 so that the phase current switches to the current value in the parallel winding state with the correction current for correcting the change being added.

  At this time, since the winding group 50 to be switched is connected to the neutral point 51 via the electronic changeover switch 100, a phase current and a correction current can be supplied to the winding group 50 to be switched. Even if the switching is performed while outputting the torque, the fluctuation of the output torque can be suppressed by the phase current and the correction current.

  The PCM 5 controls the switching mechanism 31 at the same time or slightly after turning on the electronic changeover switch 100, and starts switching the mechanical contacts 81 and 83 of the relay 70 '(step S23). Since the amount of current flowing through the second winding element 50b is small, occurrence of overcurrent can be avoided, and switching can be performed while suppressing damage to the mechanical contacts 81 and 83.

  Then, after a predetermined switching period t1 at which the mechanical contacts 81 and 83 are switched, the first contact 81 is switched to the third contact 83 as shown in a schematic diagram on the right side indicated by a broken line in FIG. The switching between 81 and 83 ends. In FIG. 11, the third contact 83 is closed at the point P2.

  When the switching of the mechanical contacts 81 and 83 is completed (Yes in step S24), the PCM 5 controls the inverter 32 at the same time as that, and stops the supply of the correction current (step S25). As a result, the motor 30 transitions from the series winding state to the parallel winding state at a higher speed than when only the mechanical contacts are used, while continuously outputting torque.

(Switch from parallel winding state to series winding state)
FIG. 13 shows an example of the phase current in the switching control of the winding state during the energization of the motor (switching from the parallel winding state to the series winding state). FIG. 14 shows an example of the switching control.

  When the rotation speed of the motor 30 reaches a predetermined low rotation region and there is a request to switch the winding state (Yes in step S30), the PCM 5 is configured to output a signal based on a signal input from the ammeter of the inverter 32. Then, the timing at which the phase current flowing through the winding group 50 to be switched becomes zero crossing is determined (step S31).

  Then, the PCM 5 controls the switching mechanism 31 at the timing of or near zero crossing where the phase current flowing through the winding group 50 to be switched becomes substantially zero, and switches the mechanical contacts 81 and 83. Start (step S32). In FIG. 13, switching of the mechanical contacts 81 and 83 is started at a point P3.

  As a result, as shown in the schematic diagram on the left side shown by the broken line in FIG. 13, the first contact 81 is opened, and the first winding element 50a is connected in series with the second bypass wiring 64. Since the torque constant changes accordingly, the PCM 5 adds a correction current for correcting the change, and controls the inverter 32 so that the fluctuation of the output torque is suppressed (step S33).

  Then, after a predetermined switching period t2 in which the mechanical contacts 81 and 83 are switched, the switching of the mechanical contacts 81 and 83 is completed as shown in the schematic diagram on the right side shown by the broken line in FIG. 83 is closed (the timing of point P4 in FIG. 13). That is, the second winding element 50b is connected in parallel with the second bypass wiring 64.

  When the switching of the mechanical contacts 81 and 83 is completed (Yes in step S34), the PCM 5 controls the switching mechanism 31 at the same time as that, and changes the state from the state of the schematic diagram on the right side indicated by the broken line in FIG. The second switch 62 is turned off (step S35). Since the second switch 62 is the electronic changeover switch 100, it can be turned off instantaneously.

  At the same time, the inverter 32 is controlled to change the value of the phase current to the series winding state (step S36). As a result, the motor 30 transitions from the parallel winding state to the series winding state winding state at a higher speed than when only the mechanical contacts are used, while continuously outputting torque.

  In the case of the control device of this application example, there is also an advantage that stable running of the vehicle 1 can be maintained even when the relay 70 'is damaged. For example, when the third contact point 83 is stuck, the electronic changeover switch 100 is turned on and off to easily switch between a series winding state and a winding state advantageous for high rotation (decreasing winding state). Can be. However, in the reduced winding state, since the second winding element 50b is short-circuited by the second bypass wiring 64, only the first winding element 50a is used.

  In addition, when the first contact 81 is fixed, or when the first contact 81 and the third contact 83 do not come into contact with each other, the electronic changeover switch 100 is held in an on state, It can be maintained in a parallel winding state. In the parallel winding state, motor characteristics advantageous at high speed can be exhibited. Therefore, the vehicle 1 can be operated smoothly by driving the engine 2.

  In addition, the disclosed technology is not limited to the above-described embodiment, but includes various other configurations. For example, the technology to be disclosed is not limited to HEV. The disclosed technology is also suitable for an electric vehicle equipped with only a motor as a drive source. The structure of the motor is also an example.

DESCRIPTION OF SYMBOLS 1 Vehicle 2 Engine 3 Motor generator 4 Low voltage power supply 5 PCM (an example of a control unit)
Reference Signs List 30 motor 31 switching mechanism 32 inverter 50 winding group 70 relay 81 first contact 82 second contact 83 third contact

Claims (5)

A control device for the motor generator,
A motor provided with a plurality of different winding groups,
A measuring unit for detecting an operating state of the motor;
An inverter that drives and controls the motor by supplying alternating current having a different phase to each of the winding groups;
A switching mechanism connected between the motor and the inverter;
A control unit that controls the inverter and the switching mechanism based on a signal input from the measurement unit;
With
Each of the winding groups is composed of a plurality of winding elements,
The switching mechanism opens and closes between a series winding state in which the winding elements are connected in series and a parallel winding state in which the winding elements are connected in parallel according to an operation state of the motor. By switching the connection state of each of the winding group by having a plurality of contacts,
The control device for a motor generator, wherein the switching mechanism unit includes a relay, and at least one of the plurality of contacts is configured by a mechanical contact of the relay. The control device for a motor generator according to claim 1,
The plurality of contacts comprises three mechanical contacts that switch each of the winding groups to one of the series winding state and the parallel winding state,
Said relay,
A plurality of terminals comprising a fixed terminal and a movable terminal constituting the three mechanical contacts;
A movable part supporting the movable terminal,
One action unit that operates the movable unit according to the control of the control unit;
Has,
A control device for a motor generator, wherein the opening and closing states of the three mechanical contacts are simultaneously switched by the action section operating the movable section. The control device for a motor generator according to claim 1 or 2,
A control device for a motor generator, wherein the control unit controls the inverter such that an alternating current flowing through the mechanical contact becomes substantially zero at a timing when the mechanical contact is opened and closed. The control device for a motor generator according to claim 1,
The plurality of contacts includes three contacts that switch each of the winding groups to one of the series winding state and the parallel winding state,
The switching mechanism further includes an electronic changeover switch formed of an electric circuit,
The control device for a motor generator, wherein the three contacts include a mechanical contact of the relay and an electric contact of the electronic changeover switch. The control device for a motor generator according to claim 4,
The control unit supplies a correction current through the electronic changeover switch at a timing when the mechanical contact is opened and closed, so that an alternating current flowing through the winding group corresponding to the mechanical contact and the electronic changeover switch is provided. A control device for the motor generator, which controls the switching mechanism and the inverter such that the correction is made.

Images