JP2017112819A - Phase number switching type electric machine - Google Patents

Abstract

A novel winding number switching type electric machine is provided.
A phase number switching electric machine capable of triple the number of poles is provided. The stator coil 1 is composed of a plurality of series three-phase windings 1U, 1V, 1W connected to a 4-leg converter 2, respectively. Three H-bridges individually connected to the three independent phase coils 5 can be employed instead of the series three-phase winding connected to the four-leg converter 4. The machine has a single-phase mode in addition to the conventional three-phase mode. Single phase mode has excellent low speed performance. In order to triple the number of rotor poles, the direction of the field current can be reversed.
[Selection] Figure 1

Description

The present invention relates to a phase number switching type electric machine, and more particularly to a phase number switching type electric machine capable of changing the number of phases, the number of poles and the number of turns.

Patent Documents 1-3 propose a triple pole type synchronous machine capable of triple the number of rotor poles. Patent Document 1 proposes a permanent magnet type synchronous machine whose rotor has a core pole and a magnet pole. The core pole disposed between the two magnet poles can reverse the polarity. The magnet pole means a rotor pole magnetized by a permanent magnet. The core pole means a rotor pole that is magnetized by an exciting current. Due to the polarity reversal of the core poles, the 12 rotor poles become equivalent to 4 rotor poles.

Patent Document 2 proposes a field coil synchronous generator in which a rotor has one magnet pole between two core poles. The field coil is wound around the root of one magnet pole and the two core poles. By reversing the direction of the field current supplied to the field coil, the polarity of the core pole is changed. Thereby, 12 rotor poles become equivalent to 4 rotor poles.

Patent Document 3 proposes a permanent magnet synchronous generator whose rotor has a soft permanent magnet pole and a hard permanent magnet pole. One soft magnet pole whose polarity can be reversed is arranged between two hard permanent magnet poles whose polarity is not reversed.

However, when the number of rotor poles is tripled, the electrical angle of the stator is 120 degrees and the electrical angle is 360 degrees. From the viewpoint of manufacturing cost and power loss, it is difficult to change the number of stator poles.

Patent 5605164 WO2008 / 148621 JP2013-183515A JP2011-223748

One object of the present invention is to provide a simple phase number switching type electric machine capable of changing the number of phases and the number of poles. Another object of the present invention is to provide a simple phase number switching type electric machine capable of changing the number of phases, the number of poles and the number of turns.

According to the present invention, a stator coil having at least three phase coils handles a three-phase mode that handles a three-phase stator current supplied to the three-phase coils, and a single-phase stator current supplied to the three-phase coils. It has a single-phase mode. The single phase mode has three times as many poles as the three phase mode. This electric machine operated in single phase mode has excellent low speed performance.

According to one preferred embodiment, at least one series three-phase winding is connected to one four-leg converter consisting of four legs individually connected to the ends of the three phase coils of the series three-phase winding. The Thereby, the number of poles and the number of phases are each tripled in the single-phase mode. The electric machine includes a permanent magnet synchronous machine or a field coil synchronous machine or an induction machine. The 4-leg converter includes a 4-leg diode rectifier, a 4-leg inverter, and a 4-leg hybrid converter. The 4-leg diode rectifier executes a three-phase power generation mode and a single-phase power generation mode. The 4-leg inverter executes a three-phase electric mode, a single-phase electric mode, a three-phase power generation mode, and a single-phase power generation mode. The four-leg hybrid converter executes a single-phase electric mode, a three-phase power generation mode, and a single-phase power generation mode.

This phase number switching type electric machine can have a plurality of series three-phase windings.
According to one example, two series three-phase windings are operated in two-phase mode and six-phase mode. The two-phase mode is essentially equal to the two single-phase modes. The six-phase mode is essentially equal to the two three-phase modes. Two series three-phase windings can be connected in series with each other.

According to another example, three series three-phase windings are operated in the new three-phase mode and nine-phase mode. The new three-phase mode is essentially equal to the three single-phase modes. The nine-phase mode is essentially equal to the three three-phase modes. The three series three-phase windings can be connected in series with each other.

By adopting the two-phase driving method, the switching loss of the four-leg inverter in the three-phase mode can be reduced. A boost chopper applies a boosted DC link voltage to the inverter. According to this two-phase driving method, the two legs of the four-leg inverter are stopped and the remaining two legs are switched. The step-up chopper applies a part of the substantially sinusoidal phase voltage to the phase coils individually connected to both ends of the two legs that are stopped at both ends.

By adopting a four-leg hybrid converter composed of two switch legs and two diode legs, a simple starter generator connected to two power supplies can be realized. The two switch legs are connected to a high voltage power supply and the two diode legs are connected to a low voltage power supply.

In order to switch the number of rotor poles, it is possible to employ a Landel rotor core having both field coils and permanent magnets. Each permanent magnet is fixed to the central portion of each claw portion of the Landel rotor core. Each claw has two core parts adjacent to the permanent magnet. The polarity of the core is reversed by the field current. Thereby, the number of rotor poles is switched.

The field coil electric machine can employ a field coil composed of a plurality of coils. Each coil is wound in a different slot of the tees-type rotor core.
The direction of the field current supplied to a part of each coil is reversed for switching the number of rotor poles. The direction of the field current supplied to the remainder of each coil is not reversed. Thereby, the number of rotor poles is switched.

It is also possible to switch the number of rotor poles depending on the d-axis current component of the starter current. The rotor core has a magnet pole and a core part. In order to switch the number of rotor poles, the d-axis current component reverses the polarity of the core pole.

FIG. 1 is a wiring diagram showing a first embodiment. FIG. 2 is a cross-sectional view showing the terminal ring shown in FIG. FIG. 3 is a wiring diagram showing a second embodiment. FIG. 4 is a side view showing the rotor core of the field coil machine. FIG. 5 is a schematic diagram showing a state of an electrical angle of 0 degrees of a distributed winding three-phase stator coil operated in a three-phase mode. FIG. 6 is a schematic diagram showing a state of an electrical angle of 60 degrees of a distributed winding three-phase stator coil operated in the three-phase mode. FIG. 7 is a schematic diagram showing a state of an electrical angle of 0 degrees of a distributed winding three-phase stator coil operated in a single-phase mode. FIG. 8 is a schematic diagram showing a state of an electrical angle of 180 degrees of the distributed winding three-phase stator coil operated in the single-phase mode. FIG. 9 is a schematic development view showing a winding method of the distributed winding three-phase stator coil shown in FIGS. FIG. 10 is a block diagram showing a 4-leg inverter connected to the distributed winding three-phase stator coil shown in FIG. FIG. 11 is a schematic diagram showing a state of an electrical angle of 0 degrees of the concentrated winding three-phase stator coil operated in the three-phase mode. FIG. 12 is a schematic diagram showing a state of an electrical angle of 60 degrees of the concentrated winding three-phase stator coil operated in the three-phase mode. FIG. 13 is a schematic diagram showing a state of an electrical angle of 0 degrees of the concentrated winding three-phase stator coil operated in the single-phase mode. FIG. 14 is a schematic diagram showing a state of an electrical angle of 180 degrees of the concentrated winding three-phase stator coil operated in the single phase mode. FIG. 15 is a flowchart showing a control example of the starter generator according to the first embodiment. FIG. 16 is a wiring diagram showing a third embodiment. FIG. 17 is a vector diagram showing the two-phase mode of the third embodiment.
FIG. 18 is a vector diagram showing the six-phase mode of the third embodiment. FIG. 19 is a schematic diagram showing a wiring example of the concentrated winding stator coil adopted in the third embodiment. FIG. 20 is a schematic diagram showing a stator core having two series three-phase windings arranged apart from each other. FIG. 21 is a schematic developed view showing teeth of the stator core shown in FIG. FIG. 22 is a schematic diagram showing a teeth-type rotor core employed in the fourth embodiment. FIG. 23 is a wiring diagram showing a field current controller employed in the fourth embodiment. FIG. 24 is a schematic diagram showing the arrangement of rotor poles in the three-phase mode. FIG. 25 is a schematic diagram showing the arrangement of the rotor poles in the single-phase mode. FIG. 26 is a wiring diagram showing a 4-leg inverter of the fifth embodiment. FIG. 27 is a wiring diagram showing a first current state of a four-leg inverter driven in the three-phase mode. FIG. 28 is a wiring diagram showing a second current state of the 4-leg inverter driven in the three-phase mode. FIG. 29 is a wiring diagram showing a third current state of the four-leg inverter driven in the three-phase mode. FIG. 30 is a wiring diagram showing a fourth current state of the 4-leg inverter driven in the three-phase mode. FIG. 31 is a wiring diagram showing a fifth current state of the 4-leg inverter driven in the three-phase mode. FIG. 32 is a wiring diagram showing a sixth current state of the 4-leg inverter driven in the three-phase mode. FIG. 33 is a wiring diagram showing a first current state of a 4-leg inverter driven in the single-phase mode. FIG. 34 is a wiring diagram showing a second current state of the 4-leg inverter driven in the single-phase mode. FIG. 35 is a wiring diagram showing two 4-leg inverters of the sixth embodiment. FIG. 36 is a wiring diagram showing a 10-leg inverter of the seventh embodiment. FIG. 37 is a schematic development view showing the arrangement of the nine phase coils shown in FIG. FIG. 38 is a vector diagram showing the new three-phase mode. FIG. 39 is a vector diagram showing the nine-phase mode.

A preferred embodiment of the present invention relating to a phase number switching type AC electric machine capable of switching the number of phases, the number of poles and the number of turns will be described with reference to the drawings.

First Embodiment An alternator shown in FIG. 1 has a stator coil 1, a diode rectifier 2, an H bridge 4, a field coil 5, a controller 6 and a terminal ring 7. The H bridge 4 and the terminal ring 7 constitute a field current controller controlled by the controller 6. The stator coil 1 which is a series three-phase winding is composed of three phase coils 1U, 1V and 1W connected in series. Phase coils 1U, 1V, and 1W are 120 degrees apart from each other in the three-phase mode and 0 degrees away from each other in the single-phase mode.

When the field current is supplied to the field coil 5, the phase coil 1U generates the U-phase electromotive force Vu, the phase coil 1V generates the V-phase electromotive force Vv, and the phase coil 1W generates the W-phase electromotive force Vw. Occur.

The diode rectifier 2 connected to the battery 9 comprises four diode legs 2A-2D. The diode leg 2 constitutes a 4-leg converter. The leg 2A includes an upper arm diode 21 and a lower arm diode 22 connected in series. The leg 2B includes an upper arm diode 23 and a lower arm diode 24 connected in series. The leg 2C includes an upper arm diode 25 and a lower arm diode 26 connected in series. The leg 2D includes an upper arm diode 27 and a lower arm diode 28 connected in series.

The AC terminal of the leg 2A is connected to one end of the phase coil 1U. The AC terminal of the leg 2B is connected to the other end of the phase coil 1U and one end of the phase coil 1V. The AC terminal of the leg 2C is connected to the other end of the phase coil 1V and one end of the phase coil 1W. The AC terminal of the leg 2D is connected to the other end of the phase coil 1W. The positive DC terminal of the legs 2A-2D is connected to the positive electrode of the battery 9. The negative DC terminal of the legs 2A-2D is connected to the negative electrode of the battery 9.

The H bridge 4 consists of two legs 4A and 4B. The leg 4A includes an upper arm switch 45 and a lower arm switch 42 connected in series. The leg 4B includes an upper arm switch 41 and a lower arm switch 46 connected in series. The switches 41, 42, 45 and 46 are NMOS transistors having antiparallel diodes. The drain electrodes of the switches 41 and 45 are connected to the positive electrode of the battery 9. The source electrodes of the switches 42 and 46 are connected to the negative electrode of the battery 9.

A field coil 5 including coils 53 and 55 is wound around a tees-type rotor core 13 shown in FIG. The terminal ring 7 has four diodes 74-77. The AC terminal of the leg 4A is connected to the anode electrode of the diode 74 and the cathode electrode of the diode 77. The cathode electrodes of the diodes 74 and 76 are connected to one end of the coil 53. The other end of the coil 53 is connected to the anode electrodes of the diodes 75 and 77. The AC terminal of the leg 4B is connected to the anode electrode of the diode 76 and the cathode electrode of the diode 75. Further, the coils 54 and 55 are connected in parallel between the legs 4A and 4B.

The field current controller controls the field current supplied to the field coil 5. The field current flows from the switch 45 to the switch 46 in the three-phase power generation mode. The field current flows from the switch 41 to the switch 42 in the single-phase power generation mode. The flow direction of a part of the field current flowing through the coil 53 is constant even if the mode is changed. However, the flow direction of the remaining field current flowing through the coils 54 and 55 is opposite when the mode is changed.

The tees-type rotor core 13 shown in FIG. 22 has two rotor poles equivalently in the three-phase power generation mode and equivalently six rotor poles in the single-phase power generation mode. In other words, the polarity of the rotor poles 131 and 132 is changed by changing the direction of the field current supplied to the coils 54 and 55. One rotor pitch in the three-phase mode is equal to three stator teeth pitch. Similarly, one rotor pitch in the single phase mode is equal to one stator teeth pitch. In other words, one stator teeth pitch is equal to 60 electrical angles in the three-phase mode, and equal to 180 electrical angles in the single-phase mode.

FIG. 2 is a side view of the terminal ring 7. A rotating shaft 10 that is a rotor shaft is supported by a motor housing 11. The terminal ring 7 adjacent to the rotor core 13 is fixed to the rotating shaft 10. Four connection terminals protrude from the terminal ring 7 to connect the diodes 74 to 77 to the slip ring (not shown) and the field coil 5. FIG. 2 shows only three connection terminals 71-73. The diodes 74 to 77 are embedded in the terminal ring 7 made of heat resistant resin.

The field current is adjusted by controlling the duty ratio of the switch 45 in the three-phase mode. Further, the field current is adjusted by controlling the duty ratio of the switch 41 in the single phase mode. Phase coils 1U, 1V and 1W individually generate phase voltages Vu, Vv and Vw having substantially sinusoidal waveforms, respectively. The phase difference between any two of the three phase voltages Vu, Vv, and Vw is 120 electrical degrees in the three-phase mode. The phase difference between any two of the three phase voltages Vu, Vv, and Vw is 0 electrical angle in the single phase mode. In other words, the three phase voltages Vu, Vv and Vw are in phase with each other in the single phase mode.

According to the three-phase mode, the four diode legs 2A-2D rectify the three phase voltages Vu, Vv and Vw. According to the single phase mode, the two legs 2A and 2D rectify the sum of the three phase voltages Vu, Vv and Vw.

The single phase mode has three times the number of poles and three times the number of turns compared to the three phase mode. Therefore, the alternator generates a high generated voltage in the low speed region. That means that the alternator can reduce copper loss by reducing the number of turns of the stator coil 1.

Second Embodiment A starter generator according to a second embodiment will be described with reference to FIG. This field coil starter generator includes a stator coil 1, a hybrid converter 2H, a battery switch 3, an H bridge 4, a field coil 5, and a controller 6. The hybrid converter 2H constitutes a 4-leg converter. The H bridge 4 constituting the field current controller is the same as the H bridge 4 shown in FIG. The controller 6 that selects either the three-phase mode or the single-phase mode controls the hybrid converter 2H, the battery switch 3, and the H bridge 4. A stator coil 1 called a series three-phase winding is composed of three phase coils 1U, 1V and 1W connected in series.

A starter generator, which is a Landell-type field coil synchronous machine, has a three-phase power generation mode, a single-phase power generation mode, and a single-phase motor mode. The three-phase power generation mode and the single-phase power generation mode are essentially the same as in the first embodiment. However, the starter generator employs a Landell type rotor core instead of the tee type rotor core of the first embodiment.

The hybrid converter 2H includes two switch legs 2A and 2D and two diode legs 2B and 2C. The switch leg 2A includes an upper arm switch 21 and a lower arm switch 22 connected in series. The switch leg 2D includes an upper arm switch 27 and a lower arm switch 28 connected in series. Each of the switches 21, 22, 27, and 28 includes an NMOS transistor having an antiparallel diode. The diode leg 2B includes an upper arm diode 23 and a lower arm diode 24 connected in series. The diode leg 2C includes an upper arm diode 25 and a lower arm diode 26 connected in series.

The AC terminal of the switch leg 2A is connected to one end of the phase coil 1U. The AC terminal of the switch leg 2D is connected to one end of the phase coil 1W. The AC terminal of the diode leg 2B is connected to the connection point of the phase coils 1U and 1V. The AC terminal of the phase coil 2C is connected to the connection point of the phase coils 1V and 1W.

The positive DC terminals of the switch legs 2A and 2D are connected to the positive electrode of the high voltage capacitor 8. The positive DC terminals of the diode legs 2B and 2C are connected to the positive electrode of the high voltage capacitor 8. The negative electrodes of the capacitor 8 and the battery 9 are grounded. The battery switch 3 is composed of an NMOS transistor having an antiparallel diode. The anode electrode of the antiparallel diode is connected to the positive electrode of the battery. For example, the rated voltage of the battery 9 is 14V, and the maximum voltage of the capacitor 8 is about 50V. The terminals of the switch legs 4A and 4B of the H bridge 4 are individually connected to both ends of the field coil 5.

FIG. 4 is a side view showing a Landell-type rotor having a well-known Landell-type rotor core 12 fixed to the rotating shaft 10. The field coil 5 is wound around a boss portion of a soft iron rotor core 12. The rotor core 12 has four claw portions 61-64 arranged at an equal pitch in the rotation direction of the shaft 10. The L-shaped claw portions 61 and 62 respectively project from the one end of the boss portion of the rotor core 12 in the radial direction of the boss portion, and then extend forward along the inner peripheral surface of the stator core (not shown). . Each of the L-shaped claw portions 63 and 64 protrudes from the other end of the boss portion of the rotor core 12 in the radial direction of the boss portion, and then extends rearward along the inner peripheral surface of the stator core (not shown). Yes.

Each outer peripheral surface of the claw portions 61-64 facing a stator core (not shown) has a recess 60. Each recessed part 60 is arrange | positioned at each center part of the outer peripheral surface of the nail | claw part 61-64. A permanent magnet 65 is fixed to the recess 60 of the claw portion 61. A permanent magnet 66 is fixed to the recess 60 of the claw portion 62. The outer surface portions of the permanent magnets 65 and 66 are magnetized and have an N pole. Similarly, the permanent magnet 67 is fixed to the concave portion 60 of the claw portion 63. A permanent magnet 68 is fixed to the recess 60 of the claw portion 64. The outer surface portions of the permanent magnets 67 and 68 are magnetized and have an S pole. Each outer peripheral surface portion of the claw portions 61-64 has two core portions 69 that sandwich the recess 60. After all, the eight core portions 69 and the four permanent magnets 65-68 are arranged in the rotation direction at an equal pitch.

According to the three-phase power generation mode, a field current flows from the leg 4A through the field coil 5 to the leg 4B. By flowing a field current from the leg 4A to the leg 4B, the four core portions 69 of the claw portions 61 and 62 are magnetized to have an N pole, and the four core portions 69 of the claw portions 63 and 64 are magnetized to be S. With poles. Since the core portion 69 of the claw portions 61 and 62 has the same polarity as the permanent magnets 65 and 66, each of the claw portions 61 and 62 is equivalent to one rotor pole having N poles. Similarly, since the core part 69 of the claw parts 63 and 64 has the same polarity as the permanent magnets 67 and 68, each of the claw parts 63 and 64 is equivalent to one rotor pole having an S pole. After all, the Landel rotor core has four rotor poles equivalently in the three-phase mode.

According to the single-phase power generation mode and the single-phase electric mode, the field current flows from the leg 4B through the field coil 5 to the leg 4A. Due to the field current supplied by the capacitor 8, the four core portions 69 of the claw portions 61 and 62 are magnetized to have the S pole, and the four core portions 69 of the claw portions 63 and 64 are magnetized to have the N pole. . The polarity of the permanent magnets 65-68 is not changed by the field current. Accordingly, the Landell rotor core 12 has 12 rotor poles in the single phase mode. Eventually, the number of rotor poles is tripled by reversing the field current.

The rectification of the hybrid converter 2H is essentially the same as the rectification of the diode rectifier 2. Phase coils 1U, 1V, and 1W generate back electromotive forces Vu, Vv, and Vw that are 120 degrees apart from each other in the three-phase power generation mode. Therefore, the sum of the counter electromotive forces Vu, Vv and Vw becomes zero in the three-phase power generation mode.

Next, the single-phase electric mode will be described. According to the single-phase electric mode, the phase coils 1U, 1V and 1W generate back electromotive forces Vu, Vv and Vw that are equal to each other. The switch legs 2A and 2D supply a single-phase current to the three phase coils 1U, 1V and 1W connected in series. Therefore, the starter generator is a single-phase synchronous motor.

However, the single-phase synchronous motor has a dead point where the motor torque becomes zero. According to one example, when an engine start is commanded, fuel injected into a predetermined cylinder of the engine is ignited. As a result, the starter generator Randell rotor connected to the crankshaft of the engine can start rotating in the initial stage of engine start.

The advantages of the second embodiment will be described. First, the capacitor 8 can be charged by the boosted battery voltage. When the voltage of the capacitor 8 is low, this step-up charging using the field coil 5 as a reactor is executed. Second, the high voltage of the capacitor 8 can rapidly increase the field current during the engine start period.

The starter current supplied in the three-phase mode and the single-phase mode will be described with reference to FIGS. A stator coil composed of series three-phase windings is accommodated in six slots 102 of a stator core 100 having six teeth 101.

5 to 8 show distributed winding stator coils. A U-phase coil 1U shown in FIG. 3 includes an outward conductor U and a return conductor -U connected in series. Similarly, the V-phase coil 1V includes a forward conductor V and a return conductor -V connected in series. W-phase coil 1W is composed of forward conductor W and return conductor -W connected in series. The conductor U is accommodated in the first slot 102. The conductor-U is accommodated in the fourth slot 102. The conductor V is accommodated in the second slot 102. The conductor V is accommodated in the fifth slot 102. The conductor W is accommodated in the third slot 102. The conductor -W is accommodated in the sixth slot 102.

5 and 6 show the three-phase mode. Each phase difference between any two of the three phase currents is an electrical angle of 120 degrees. In FIG. 5, three phase currents flowing separately through three adjacent conductors -W, U, and -V are in opposite directions to three phase currents flowing separately through three adjacent conductors W, -U, and V. It becomes. Thereby, the stator core 100 has substantially two stator poles.

In FIG. 6, the three phase currents flowing separately through the three adjacent conductors U, -V and W are opposite to the three phase currents flowing separately through the three adjacent conductors -U, V and -W. It becomes. Thereby, the stator core 100 has substantially two stator poles. The magnetic field of the stator core 100 shown in FIG. 6 rotates by an electrical angle of 60 degrees with respect to the magnetic field of the stator core 100 shown in FIG. Eventually, a three-phase magnetic field having two stator poles is formed. This three-phase magnetic field is the same as the three-phase magnetic field formed by the conventional distributed winding three-phase winding.

7 and 8 show the single phase mode. Each phase difference between any two of the three phase currents is an electrical angle of 0 degrees. In other words, the U-phase current, the V-phase current, and the W-phase current are in phase. The phase current flowing through the conductors accommodated in the odd-numbered slots flows in the opposite direction to the phase current flowing through the conductors accommodated in the even-numbered slots.

FIG. 7 shows three phase currents when the electrical angle of the rotor is 0 degrees. FIG. 8 shows three phase currents when the rotor electrical angle is 180 degrees. In FIG. 7, the phase currents flowing through the odd-numbered conductors U, V and W flow in the return direction, and the phase currents flowing through the even-numbered conductors -U, -V and -W flow in the forward direction. Therefore, the stator core 100 has six stator poles.

In FIG. 8, the phase currents flowing through the odd-numbered conductors U, V and W flow in the forward direction, and the phase currents flowing through the even-numbered conductors -U, -V and -W flow in the return direction. Therefore, the stator core 100 has six stator poles. Eventually, the three phase currents in phase with each other form a three-phase rotating magnetic field with six stator poles.

9 and 10 show one winding example of the distributed winding series three-phase winding shown in FIGS. Six subcoils C1-C6 are wound around six slots S1-S6 of the stator core. U-phase coil 1U consists of sub-coils C1 and C4 connected in series. V-phase coil 1V consists of sub-coils C2 and C5 connected in series.
W-phase coil 1W includes sub-coils C3 and C6 connected in series. In order to supply the U-phase current IU, V-phase current IV and W-phase current IW, the four switch legs 2A, 2B, 2C and 2D of the 4-leg inverter 2I are individually connected to the ends of the phase coils 1U, 1V and 1W. It is connected to the.

FIGS. 11-14 show concentrated series 3-phase windings. The U-phase coil includes a subcoil U and a subcoil -U connected in series. The V-phase coil includes a subcoil V and a subcoil -V connected in series. The W-phase coil includes a subcoil W and a subcoil -W connected in series. The subcoil U is wound around the first tooth 101 of the stator core 100, and the subcoil U is wound around the fourth tooth 101 of the stator core 100. The subcoil V is wound around the second tooth 101 of the stator core 100, and the subcoil V is wound around the fifth tooth 101 of the stator core 100. The subcoil W is wound around the third tooth 101 of the stator core 100, and the subcoil W is wound around the sixth tooth 101 of the stator core 100.

11-12 show the three-phase mode. Each phase difference between any two of the three phase currents is an electrical angle of 120 degrees. In FIG. 11, the subcoils -W, U and -V have the same current direction. Thereby, the stator core has substantially two stator poles. In FIG. 12, subcoils U, -V and W have the same direction. Thereby, the stator core has substantially two stator poles. The magnetic field of the stator core 100 shown in FIG. 12 is shifted by an electrical angle of 60 degrees compared to the magnetic field of the stator core 100 shown in FIG. This three-phase magnetic field of the stator core 100 is the same as the three-phase magnetic field formed in the conventional concentrated winding three-phase motor.

13 and 14 show the single phase mode. Each phase difference between any two of the three phase currents is an electrical angle of 0 degrees. In other words, the U-phase current, the V-phase current, and the W-phase current are equal to each other. The magnetic field of the stator core 100 shown in FIG. 14 is shifted by an electrical angle of 180 degrees with respect to the magnetic field of the stator core 100 shown in FIG. According to FIG. 13, the odd-numbered teeth 101 are N poles, and the even-numbered teeth 101 are S poles. According to FIG. 14, the odd-numbered teeth 101 are S poles, and the even-numbered teeth 101 are N poles. When the single-phase current flows through the three-phase coils, the stator core 100 has six poles because the odd-numbered teeth have the opposite polarity to the even-numbered teeth.

Starter Generator Operation Control Starter generator operation control will be described with reference to FIG.
Recovery Mode First, it is determined whether or not the voltage Vc of the capacitor 8 is sufficient (S100). If the capacitor voltage Vc is lower than the predetermined threshold value Vth, the recovery mode is executed. According to this recovery mode, the switches 41 and 42 are turned off, and the switches 45 and 46 are switched synchronously (S102). When the switches 45 and 46 are turned on, a field current is supplied from the battery 9 to the field coil 5. When the switches 45 and 46 are turned off, the regenerative current flows into the capacitor 8 through the antiparallel diodes of the switches 42 and 41. When the voltage Vc reaches the predetermined threshold value Vth, the recovery mode is terminated.

Engine start mode When engine start is commanded (S104), the engine start mode is executed (S106). First, the fuel injected into a predetermined cylinder of the vehicle engine is ignited to start rotating the rotor of the starter generator. Further, when the switches 41 and 42 are turned on, the field current is applied to the field coil 5. Since the capacitor voltage Vc is high, the field current rises rapidly.

Next, the single-phase electric mode is started. Switching of the switch legs 2A and 2D based on the rotation angle of the rotor angle supplies a single-phase stator current to the phase coils 1U, 1V and 1W. The battery switch 3 is not turned on. Since both the number of poles and the number of turns are tripled, a powerful engine starting torque is generated.

Capacitor Recovery Mode Next, when it is determined that the engine start has been completed, the capacitor recovery mode is executed (S108). According to the capacitor recovery mode, the single-phase power generation mode is executed. A field current is supplied from the capacitor 8 to the field coil 5. The sum of the single-phase voltages generated by the phase coils 1U, 1V and 1W is applied to the capacitor 8 after rectification of the two switches 2A and 2D. The field current is adjusted by controlling the duty ratio of the switch 41. When the capacitor voltage Vc exceeds a predetermined threshold value Vth, the switches 41 and 42 are turned off. The battery switch 3 is not turned on.

When the sum of the phase voltages Vu, Vv and Vw is less than a predetermined threshold due to the low engine speed, the boosting operation may be performed. According to this boosting operation, the lower arm switches 22 and 28 are synchronously switched. When the lower arm switches 22 and 28 are turned on, magnetic energy is stored in the phase coils 1U, 1V and 1W. After the lower arm switches 22 and 28 are turned off, the sum of the boosted phase voltages Vu, Vv and Vw charges the capacitor 8.

Power Generation Mode Next, when the voltage of the battery 9 is lower than a predetermined value, the battery 9 is charged in the three-phase power generation mode (S110). First, the switches 41 and 42 are turned off, and the battery switch 3 is turned on. Because of the direction reversal of the field current, the number of poles and the number of turns are each 1/3 compared to the single-phase electric mode. Phase coils 1U, 1V, and 1W generate three phase voltages Vu, Vv, and Vw, each of which has an electrical angle of 120 degrees. The 4-leg converter 2H rectifies three phase voltages. The rectified voltages output from the diodes 23 and 25 have envelope waveforms of the positive half wave of the U phase voltage Vu, the negative half wave of the W phase voltage Vw, and the full wave of the V phase voltage Vv. The ripple of the rectified voltage applied to the battery 9 is increased compared to the rectified voltage of the conventional three-phase diode rectifier.

When the battery 9 cannot be charged because the three-phase power generation mode is low speed, the single-phase power generation mode can be executed. Initially, switches 45 and 46 are turned off, switch 42 is turned off, and switch 41 is switched to adjust the field current. Thereby, the single phase power generation mode is executed. The rectified single-phase voltage is applied to the battery 9 through the diodes 23 and 25.

The influence of the permanent magnets 65 and 68 in the power generation mode will be described. Even if the field current is zero, permanent magnets 65-68 induce phase voltages Vu, Vv, and Vw. When the phase voltages Vu, Vv and Vw induced by the permanent magnets 65-68 are too higher than the battery charge voltage, the battery switch is turned off.

Torque assist mode When torque assist is commanded (S112), the torque assist mode is executed (S114). First, the single-phase electric mode described above is executed. A single-phase current controlled according to the rotation angle of the rotor is supplied from the capacitor 8 to the phase coils 1U, 1V and 1W by switching of the switch legs 2A and 2D.

Regenerative braking mode When regenerative braking is commanded (S116), the regenerative braking mode is executed (S118). The regenerative braking mode includes a single-phase power generation mode and a three-phase power generation mode. One of them is selected by switching the direction of the field current. The single-phase power generation mode charges the capacitor 8, and the three-phase power generation mode charges the battery 8. When the battery 9 is charged, the battery switch 3 is turned on.

Third Embodiment A starter generator according to a third embodiment will be described with reference to FIGS. The starter generator includes a stator coil 1A, a 7-leg converter 2X, a battery switch 3, an H bridge 4, a field coil 5, a controller 6, and a terminal ring 7. The H bridge 4 and the terminal ring 7 constitute a field current controller. The starter generator executes a two-phase mode instead of the single-phase mode and a six-phase mode instead of the three-phase mode. The two-phase mode is substantially equivalent to two single-phase modes, and the six-phase mode is equivalent to two three-phase modes. The two-phase mode has three times as many poles and turns as the six-phase mode.

The stator coil 1A wound around the stator core is composed of phase coils 1U, 1V, 1W, 1X, 1Y and 1Z connected in series. The stator coil 1A is called a series 6-phase winding. Phase coil 1A has a first series three-phase winding composed of phase coils 1U, 1V and 1Z, and a second series three-phase winding composed of phase coils 1X, 1Y and 1Z.

The 7-leg converter 2X has seven legs 2A, 2B, 2C, 2D, 2E, 2F, and 2G. The 7-leg converter 2X is equivalent to a first 4-leg converter composed of legs 2A-2D and a second 4-leg converter composed of legs 2D-2G. Each of the first and second four-leg inverters has a single-phase power generation mode, a three-phase power generation mode, and a single-phase electric motor mode. The 7-leg converter 2X has a two-phase power generation mode, a six-phase power generation mode, and a two-phase electric mode. When the first and second four-leg inverters each have a single-phase mode, the two-phase mode is executed. When the first and second four-leg inverters each have a three-phase mode, the six-phase mode is executed.

The four legs 2A-2D are equal to the legs 2A-2D shown in FIG. The AC terminal of the diode leg 2E is connected to a connection point for connecting the coils 1X and 1Y. The AC terminal of the diode leg 2F is connected to a connection point for connecting the coils 1Y and 1Z. The AC terminal of the diode leg 2G is connected to the independent end of the phase coil 1Zno. U phase current IU flows through U phase coil 1U, V phase current IV flows through V phase coil 1V, and W phase current IW flows through W phase coil 1W. Similarly, the X-phase current IX flows through the X-phase coil 1X, the Y-phase current IY flows through the Y-phase coil 1Y, and the Z-phase current IZ flows through the Z-phase coil 1Z.

The field current controller shown in FIG. 16 is essentially the same as the field current controller shown in FIG. However, according to FIG. 16, the three coils 53-55 are connected in series. The direction of the field current flowing through the coil 53 can be reversed. The three coils 53-55 are wound around the tees-type rotor core 13 shown in FIG. The terminal ring 7 has diodes 74, 76 and 77. The AC terminal of the leg 4A is connected to the anode electrode of the diode 74 and the cathode electrode of the diode 77. The cathode electrodes of the diodes 74 and 76 are connected to one end of the coil 55. The other end of the coil 55 is connected to one end of the coil 54. The other end of the coil 54 is connected to one end of the coil 53 and the anode electrode of the diode 77. The AC terminal of the leg 4 </ b> B is connected to the other end of the coil 53 and the anode electrode of the diode 76.

The field current controller has a series mode and a parallel mode. According to the series mode, the switches 41 and 42 are turned off and the switches 45 and 46 are turned on. A field current flows sequentially through the diode 74 and the coils 55, 54 and 53. A part of the field current flows through the coil 53 and the diode 77. The remainder of the field current flows in sequence through the diode 76, coil 55, coil 54, and diode 77. Eventually, the direction of the field current flowing through the coils 55 and 54 is not reversed by the mode change. However, the direction of the field current flowing through the coil 53 is reversed by the mode change. According to the parallel mode, the capacitor 8 applies a high voltage to the field coil 5, so that the field current rapidly increases. Furthermore, the equivalent impedance value of the field coil 5 is reduced. The field coil 5 and the terminal ring 7 shown in FIG. 16 switch the number of poles of the rotor and the number of turns of the field coil 5.

The 6-phase mode is executed in the serial mode, and the 2-phase mode is executed in the parallel mode. The rotor core 13 shown in FIG. 22 has substantially two rotor poles in the six-phase mode. Coils 54 and 55 have equal turns. The ratio of the number of turns of the coils 53 and 54 is determined based on the experimental results. Instead of the tees-type rotor core shown in FIG. 22, the field current controller shown in FIG. 3 and the Landell-type rotor core shown in FIG. 4 may be employed.

FIG. 17 shows six phase current vectors in the two-phase mode. According to the two-phase electric mode, the three switch legs 2A, 2D and 2G are switched. The first electromotive forces induced in the three phase coils 1U, 1V and 1W are in phase, and the second electromotive forces induced in the three phase coils 1X, 1Y and 1Z are in phase. Furthermore, the phase difference between the first electromotive force and the second electromotive force is an electrical angle of 90 degrees.

The two-phase power generation mode is used for charging the capacitor 8. The two-phase electric mode is used to start the engine. The first phase current I1 (= IU = IV = IW) flowing through the three phase coils 1U, 1V and 1W is controlled by the switch legs 2A and 2D. Similarly, the second phase current I2 (= IX = IY = IZ) flowing through the three phase coils 1X, 1Y and 1Z is controlled by the switch legs 2D and 2G. The switch leg 2D is controlled to provide a current difference (I1-I2). By controlling the switch legs 2A, 2D and 2G, the phase difference between the two currents I1 and I2 maintains an electrical angle of 90 degrees. The starter generator is a two-phase synchronous motor capable of generating engine starting torque.

FIG. 18 shows six phase current vectors in the six-phase mode. According to the 6-phase mode, the phase difference between any two of the three phase currents IU, IV and IW is an electrical angle of 120 degrees. Similarly, the phase difference between any two of the three phase currents IX, IY and IZ is 120 electrical degrees. Further, the phase difference between one phase current of the first three-phase current and one phase current of the second three-phase current is an electrical angle of 30 degrees as shown in FIG. The six-phase power generation mode is used in the power generation mode and the low speed regeneration mode. Upper arm diodes 23, 25, 29 and 31 charge battery 9 through battery switch 3.

FIG. 19 shows one winding example of the stator coil 1A wound around the stator core 100A. Stator core 100A has twelve teeth 102 within a 360-degree electrical angle range of 6-phase mode. The stator core 100A has four teeth 102 within an electric angle range of 360 degrees in the two-phase mode. Therefore, one tooth pitch corresponds to an electrical angle of 90 degrees in the 2-phase mode, and corresponds to an electrical angle of 30 degrees in the 6-phase mode.

U-phase coil 1U includes sub-coils U and -U connected in series. The subcoils U and -U form magnetic fields opposite to each other. V-phase coil 1V is composed of sub-coils V and -V connected in series. The subcoils V and -V form opposite magnetic fields. W-phase coil 1W includes sub-coils W and -W connected in series. The subcoils W and -W form opposite magnetic fields. Consists of. X-phase coil 1X includes sub-coils X and -X connected in series. The subcoils X and -X form opposite magnetic fields. Y-phase coil 1Y includes sub-coils Y and -Y connected in series. The subcoils Y and -Y form opposite magnetic fields. Z-phase coil 1Z includes sub-coils Z and -Z connected in series. Subcoils Z and -Z form opposite magnetic fields.

FIG. 20 shows another winding example of the stator coil 1A wound around the stator core 100B. Stator coil 1A includes a first three-phase coil including phase coils 1U, 1V, and 1W, and a second three-phase coil including phase coils 1X, 1Y, and 1Z. Stator core 100BA is composed of four arc-shaped core portions 201-204. Each of the core portions 201-204 occupies an area of approximately 90 degrees. The first three-phase coil is wound around core parts 201 and 202, and the second three-phase coil is wound around core parts 203 and 204. Each of the two three-phase coils is wound by the same winding method as in the first embodiment.

FIG. 21 shows an arrangement example of the teeth 102 of the stator core 100B shown in FIG. The teeth 102 of the core parts 201 and 202 are shifted by a half slot pitch of 0.5 Ps compared to the teeth 102 of the core parts 203 and 204. Therefore, the phase coils 1U, 1V and 1W wound around the core parts 201 and 202 are shifted by a half slot pitch of 0.5 Ps compared to the phase coils 1X, 1Y and 1Z wound around the core parts 203 and 204. . The half slot pitch of 0.5 Ps corresponds to an electrical angle of 90 degrees in the two-phase mode shown in FIG. Since the core parts 201 and 201 are 180 degrees apart from each other and the core parts 203 and 204 are also 180 degrees apart from each other, the mechanical vibration of the stator core 100B is reduced. The two three-phase coils may overlap at a boundary portion between two adjacent ones of the core portions 201-204.

Eventually, it can be seen that the two-phase mode is composed of two single-phase modes having a predetermined phase difference from each other, and the six-phase mode is composed of two three-phase modes having a predetermined phase difference from each other.

FIG. 22 shows the field coil 5 wound around the tees-type rotor core 13. The rotor core 13 fixed to the rotating shaft 10 is manufactured from laminated electrical steel sheets. The rotor core 13 has teeth 131-136 arranged at regular intervals. Six slots 141-146 for receiving the field coil 5 separate the teeth 131-136. The field coil 5 is composed of three coils 53-55. Coil 53 is wound around slots 145 and 146. Coil 54 is wound in slots 141 and 142. Coil 55 is wound around slots 143 and 144.

According to FIG. 1, the field current flowing through the coil 53 magnetizes the teeth 133 and 134 to the north pole and the teeth 135 and 136 to the south pole. The field current flowing through the coils 54 and 55 switches the magnetic polarity of the teeth 131 and 132 by reversing the current direction. Similarly, according to FIG. 16, the field current flowing through the coils 54 and 55 magnetizes the tows 131 to the north pole and the tows 132 to the south pole. The field current flowing through the coil 53 switches the magnetic polarity of the teeth 133-136 by reversing the direction of the field current.

It is understood that the magnetic polarity of the teeth 131-136 is changed by reversal of the field current flowing through a part of the coils 53 and 55. As a result, the rotor core 13 has 6 poles or 2 poles. FIG. 23 shows another field current controller for controlling the field current supplied to the field coil 5 shown in FIG.

Fourth Embodiment FIGS. 24 and 25 show a pole number switching type rotor. The rotor is manufactured by a laminated steel plate fixed to the rotor shaft 10. The rotor core 14 has teeth 131-136 which are magnetic salient poles arranged at an equal pitch in the circumferential direction. Permanent magnets 52-55 are embedded in teeth 131 and 132 called magnet poles. Teeth 133-136 without permanent magnets are called core poles. The permanent magnet 55 embedded in the magnet pole 131 gives an N pole to the outer surface of the magnet pole 131. The permanent magnet 52 embedded in the magnet pole 132 gives the S pole to the outer surface of the magnet pole 132.

A groove 145 serving as a magnetic barrier is formed between the two core poles 133 and 135. A groove 146 that is a magnetic barrier is formed between the two core poles 134 and 136. The magnetic barrier 141 is formed between the magnet pole 131 and the core pole 133. The magnetic barrier 142 is formed between the magnet pole 131 and the core pole 134. The magnetic barrier 143 is formed between the magnet pole 132 and the core pole 135. The magnetic barrier 144 is formed between the magnet pole 132 and the core pole 136.

FIG. 24 shows one arrangement of rotor poles in three-phase mode or six-phase mode. The d-axis current component of the stator current gives the N pole to the core poles 133 and 134 and reinforces the N pole of the magnet pole 131. Similarly, the core poles 135 and 136 are S poles, and the S pole of the magnet pole 132 is reinforced. Eventually, the rotor core 14 has substantially two poles. The so-called d-axis passes through the centers of the magnet poles 131 and 132. The so-called q axis passes through the centers of the grooves 145 and 146.

FIG. 25 shows another arrangement of rotor poles in single-phase mode or two-phase mode. The electrical angle 360 degrees in the single-phase mode or the two-phase mode is equal to the electrical angle 120 degrees in the three-phase mode or the six-phase mode. The stator current in the single-phase mode or the two-phase mode includes a d3-axis current component corresponding to a conventional d-axis current component and a q3-axis current component corresponding to a conventional q-axis current component. Due to the d3-axis current component, the core poles 133 and 134 become S poles, and the core poles 135 and 136 become N poles.
The d3 axis passes through the center of the core pole 133-136 and the center of the magnet poles 131 and 132. The q3 axis passes through the center of the grooves 145-146 and the center of the magnetic barriers 141-146. Thus, the rotor core 14 having the d3 axis and the q3 axis has six poles.

Fifth Embodiment According to the fifth embodiment shown in FIG. 26, the DC link voltage boosted by the boost chopper 80 is applied to the 4-leg inverter 2Y. The step-up chopper 80 includes a reactor 81, a lower arm switch 82, and an upper arm switch 83. The positive electrode of the battery 9 is connected to the drain electrode of the lower arm switch 82 and the source electrode of the upper arm switch 83 through the reactor 81. The source electrode of the lower arm switch 82 is grounded, and the drain electrode of the upper arm switch 83 is connected to the positive DC terminal of the 4-leg inverter 2Y. The step-up chopper 80 boosts the battery voltage of the battery 9 and applies the boost voltage to the 4-leg inverter 2Y. Instead of the eight diodes of the four-leg converter 2S shown in FIG. 1, the four-leg inverter 2Y has eight NMOS transistors with antiparallel diodes. The 4-leg inverter 2Y can execute both the three-phase electric mode and the single-phase electric mode.

A three-phase electric mode executed by the four-leg inverter 2Y shown in FIG. 26 will be described with reference to FIGS. U-phase coil 1U generates back electromotive force Vu, V-phase coil 1V generates back electromotive force Vv, and W-phase coil 1W generates back electromotive force Vw. The current I is supplied to the three phase coils 1U, 1V and 1W by the 4-leg inverter 2Y.

FIG. 27 shows a state at an electrical angle of 240 degrees where the back electromotive force Vu is the highest. FIG. 28 shows a state where the counter electromotive force Vv is the lowest and the electrical angle is 300 degrees. FIG. 29 shows a state where the back electromotive force Vw is the highest and the electrical angle is 0 degrees. FIG. 30 shows a state where the back electromotive force Vu is the lowest and the electrical angle is 60 degrees. FIG. 31 shows a state of an electrical angle of 120 degrees where the back electromotive force Vv is the highest. FIG. 32 shows a state of an electrical angle of 180 degrees where the back electromotive force Vw is the lowest.

When the switch legs 2A-2D supply three phase currents having opposite directions to the counter electromotive forces Vu, Vv and Vw, the three-phase electric mode generates motor torque. A series three-phase winding consisting of phase coils 1U, 1V and 1W is equivalent to a conventional delta-connected three-phase winding.

33 and 34 show the single-phase electric mode. The counter electromotive forces Vu, Vv and Vw are equal to each other. FIG. 33 shows the single-phase current I at an electrical angle of 0 degrees. Single-phase current I flows from switch leg 2A to switch leg 2D through three phase coils 1U, 1V and 1W. FIG. 34 shows the single-phase current I at an electrical angle of 180 degrees. Single-phase current I flows from switch leg 2D to switch leg 2A through three phase coils 1W, 1V and 1U. Thereby, motor torque is generated.

Two-phase driving method A two-phase driving method capable of reducing the switching loss in the three-phase electric mode will be described with reference to FIG. The two-phase driving method uses a boost chopper 80 and a 4-leg inverter 2Y. One cycle of the two-phase driving method with an electrical angle of 360 degrees consists of six phase periods. Each phase period is an electrical angle of 60 degrees.

According to the two-phase driving method, only two of the switch legs 2A-2D are switched at a predetermined frequency. When the phase period is changed, the switching of the other switch legs is stopped and the switched pair is changed. The step-up chopper 80 applies the requested phase voltage to the phase coil between the two stop legs.

FIG. 27 shows a first phase period in which the U-phase counter electromotive force Vu is highest. The upper arm switch 23 and the lower arm switch 22 are turned on during the first phase period. The step-up chopper 80 applies the requested U-phase voltage to the 4-leg inverter 2Y. As a result, the requested U-phase voltage i is applied to U-phase coil 1U through switches 23 and 22. By switching the switch legs 2C and 2D, the requested V-phase current is supplied to the V-phase coil 1V, and the requested W-phase current is supplied to the W-phase coil 1W.

FIG. 28 shows a second phase period in which the V-phase counter electromotive force Vu is the lowest. The upper arm switch 23 and the lower arm switch 26 are turned on during the second phase period. The step-up chopper 80 applies the requested V-phase voltage to the 4-leg inverter 2Y. As a result, the requested V-phase voltage is applied to the V-phase coil 1V through the switches 23 and 26. By switching the switch legs 2A and 2D, the requested U-phase current is supplied to the U-phase coil 1U, and the requested W-phase current is supplied to the W-phase coil 1W.

FIG. 29 shows a third phase period in which the W-phase counter electromotive force Vw is the highest. The upper arm switch 27 and the lower arm switch 26 are turned on during the third phase period. The step-up chopper 80 applies the requested W-phase voltage to the 4-leg inverter 2Y. As a result, the requested W-phase voltage is applied to the W-phase coil 1W through the switches 27 and 26. By switching the switch legs 2A and 2B, the requested U-phase current is supplied to the U-phase coil 1U, and the requested V-phase current is supplied to the V-phase coil 1W.

FIG. 30 shows a fourth phase period in which the U-phase counter electromotive force Vu is the lowest. The upper arm switch 21 and the lower arm switch 24 are turned on during the fourth phase period. The step-up chopper 80 applies the requested U-phase voltage to the 4-leg inverter 2Y. As a result, the requested U-phase voltage is i applied to U-phase coil 1U through switches 21 and 24. By switching the switch legs 2C and 2D, the requested V-phase current is supplied to the V-phase coil 1V, and the requested W-phase current is supplied to the W-phase coil 1W.

FIG. 31 shows a fifth phase period in which the V-phase counter electromotive force Vu is highest. The upper arm switch 25 and the lower arm switch 24 are turned on during the fifth phase period. The step-up chopper 80 applies the requested V-phase voltage to the 4-leg inverter 2Y. As a result, the requested V-phase voltage is applied to the V-phase coil 1V through the switches 25 and 24. By switching the switch legs 2A and 2D, the requested U-phase current is supplied to the U-phase coil 1U, and the requested W-phase current is supplied to the W-phase coil 1W.

FIG. 32 shows a sixth phase period in which the W-phase counter electromotive force Vw is the lowest. The upper arm switch 25 and the lower arm switch 28 are turned on during the sixth phase period. The step-up chopper 80 applies the requested W-phase voltage to the 4-leg inverter 2Y. As a result, the requested W-phase voltage i is applied to W-phase coil 1W through switches 25 and 28. By switching the switch legs 2A and 2B, the requested U-phase current is supplied to the U-phase coil 1U, and the requested V-phase current is supplied to the V-phase coil 1W.

The step-up chopper 80 applies a step-up voltage having a sine waveform in the range of 60 degrees electrical angle to 120 degrees electrical angle to the 4-leg inverter 2Y in each phase period. This sine waveform reaches its maximum value at an electrical angle of 90 degrees. Since two of the four switch legs are stopped, the switching loss of the four-leg inverter 2Y is halved.

Modified Embodiment An eight-leg inverter 2Z for driving two series three-phase windings shown in FIG. 35 can be used in place of the seven-leg converter 2X shown in FIG. The 8-leg inverter 2Z is composed of two 4-leg inverters 2Z1 and 2Z2. The step-up chopper 80A applies the first DC link voltage to the 4-leg inverter 2Z1, and the step-up chopper 80B applies the second DC link voltage to the 4-leg inverter 2Z2. The four-leg inverter 2Z1 connected to the three phase coils 1U, 1V and 1W is composed of four switch legs 2A1, 2B1, 2C1 and 2D1. The 4-leg inverter 2Z2 connected to the three phase coils 1X, 1Y, and 1Z includes four switch legs 2A2, 2B2, 2C2, and 2D2. 4-leg inverters 2Z1 and 2Z2 each have the same operation as 4-leg inverter 2Y shown in FIG. The phase difference between the two output voltages of the 4-leg inverters 2Z1 and 2Z2 is an electrical angle of 90 degrees in the two-phase mode. The phase difference between one phase voltage of the 4-leg inverter 2Z1 and one phase voltage of the 4-leg inverter 2Z2 is 30 electrical degrees in the 6-phase mode.

FIG. 36 shows a 10-leg inverter 2T connected to a stator coil 1B composed of nine phase coils C1-C9 connected in series. The 10-leg inverter 2T includes 10 switch legs 2A-2J. Stator coil 1B includes three series three-phase windings connected in series. The first series three-phase winding comprises phase coils C1-C3 connected in series. The second series three-phase winding is composed of phase coils C4-C6 connected in series. The third series three-phase winding is composed of phase coils C7 to C9 connected in series.

The 10-leg inverter 2T includes three 4-leg inverters. The first 4-leg inverter consists of legs 2A-2D. The second 4-leg inverter consists of legs 2D-2G. The third 4-leg inverter consists of legs 2G-2J. The first four-leg inverter is connected to the first series three-phase winding, the second four-leg inverter is connected to the second series three-phase winding, and the third four-leg inverter is connected to the third series 3 Connected to phase winding.

Phase current I1 flows to phase coil C1, phase current I2 flows to phase coil C2, phase current I3 flows to phase coil C3, phase current I4 flows to phase coil C4, phase current I5 flows to phase coil C5, Phase current I6 flows to phase coil C6, phase current I7 flows to phase coil C7, phase current I8 flows to phase coil C8, and phase current I9 flows to phase coil C9.

FIG. 37 is a schematic development view showing phase coils C1-C9 individually wound around the nine teeth 102 of the stator core 100C by concentrated winding. When three four-leg inverters are driven in single-phase mode, the motor is driven in the new three-phase mode. The phase difference between any two of the three single-phase currents supplied to the three four-leg inverters is 120 electrical degrees. FIG. 38 shows vectors of nine phase currents I1-I9 in this new three-phase mode.

When three four-leg inverters are driven in three-phase mode, the motor is driven in nine-phase mode. FIG. 39 shows vectors of nine phase currents I1-I9 in this nine-phase mode. According to this nine-phase mode, the phase difference between the phase currents I3 and I4 is 30 electrical degrees, so the current in the leg 2D is reduced. Similarly, since the phase difference between the phase currents I6 and I7 is an electrical angle of 30 degrees, the current of the leg 2G is reduced. According to this embodiment, the induction motor is driven smoothly.

Seventh Embodiment Three single-phase inverters, generally referred to as H-bridges or full-bridges, can be employed in place of the 4-leg inverters described above. The H bridge consists of a first switch leg and a second switch leg. The AC terminal of the first switch leg is connected to one end of an independent phase coil. The AC terminal of the second switch leg is connected to the other end of the independent phase coil. In the three-phase electric mode, the first H bridge supplies a U-phase current to the U-phase coil. Similarly, the second H-bridge supplies V-phase current to the V-phase coil. The third H bridge supplies W phase current to the W phase coil. The phase difference between any two of the three phase currents is an electrical angle of 120 degrees. In single phase mode, the three H-bridges supply a common phase current.

According to the seventh embodiment, only the number of poles is tripled in the single-phase electric mode, but the number of turns is not changed. Three H-bridges require twice as many transistors. However, each transistor is smaller than a conventional star-connected three-phase inverter transistor.

Claims (15)

A converter having a three-phase mode for handling a three-phase stator current and a single-phase mode for handling a single-phase stator current;
A stator coil having at least three phase coils connected to the converter;
A rotor that triples the number of rotor poles in single-phase mode compared to the number of rotor poles in three-phase mode;
A controller that selects either three-phase mode or single-phase mode;
A phase-switching electric machine comprising: The stator coil has at least one series three-phase winding consisting of three phase coils connected in series,
The phase-switching electric machine according to claim 1, wherein the converter has at least one four-leg converter consisting of four legs individually connected to the ends of three phase coils. The phase-switching electric machine according to claim 2, wherein the four-leg converter comprises four switch legs each having an upper arm transistor and a lower arm transistor connected in series. The phase-switching electric machine according to claim 2, wherein the four-leg converter comprises four diode legs each composed of an upper arm diode and a lower arm diode connected in series. The 4-leg converter consists of a 4-leg hybrid converter consisting of 2 switch legs and 2 diode legs,
Each switch leg has an upper arm transistor and a lower arm transistor connected in series,
3. The phase number switching electric machine according to claim 2, wherein each diode leg includes four diode legs each composed of an upper arm diode and a lower arm diode connected in series. The converter has at least seven legs connected to a stator coil consisting of six phase coils,
The phase number switching electric machine according to claim 2, wherein the controller selects one of a six-phase mode including two three-phase modes and a two-phase mode including two single-phase modes. The phase number switching electric machine according to claim 6, wherein the stator coil includes two series three-phase windings individually connected to two four-leg converters. 7. The phase number switching electric machine according to claim 6, wherein the converter comprises a 7-leg converter having seven legs connected to two series three-phase windings connected in series with each other. The converter has at least 10 legs connected to a stator coil consisting of 9 phase coils,
3. The phase number switching electric machine according to claim 2, wherein the controller selects one of a nine-phase mode including three three-phase modes and a new three-phase mode including three single-phase modes. The phase number switching electric machine according to claim 9, wherein the stator coil includes three series three-phase windings individually connected to three four-leg converters. 10. The phase number switching electric machine according to claim 9, wherein the converter comprises a 10-leg converter having 10 legs connected to three series three-phase windings connected in series with each other. The phase number switching electric machine according to claim 1, wherein the controller reverses the direction of the field current supplied to the field coil wound around the rotor core to triple the number of rotor poles. The Landel-type rotor core has an odd-numbered claw portion having an N-pole permanent magnet and an even-numbered claw portion having an S-pole permanent magnet.
13. The phase number switching electric machine according to claim 12, wherein each of the claw portions has one magnet pole formed of a permanent magnet and two core poles individually arranged on both sides of the magnet pole. The field coil has a variable direction coil that can change the direction of the field current.
The field coil further has a fixed coil in which the field current flows in a certain direction.
The phase change electric machine according to claim 12, wherein the direction variable coil and the direction fixed coil are accommodated in different slots of the rotor core. The rotor has two core poles arranged between two permanent magnets having opposite polarities,
The two core poles have opposite polarities due to the d-axis current component of the stator current supplied to the stator coil,
The phase number switching electric machine according to claim 1, wherein the polarities of the two core poles are reversed to triple the number of rotor poles.

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