JP5170764B2 - Electric motor drive device and control method thereof - Google Patents

Description

  The present invention relates to an electric motor drive device and a control method thereof, and more particularly to an electric motor drive device for driving an electric motor capable of adjusting an armature winding interlinkage magnetic flux amount and a control method thereof.

  Recently, hybrid vehicles and electric vehicles have attracted attention as environmentally friendly vehicles. A hybrid vehicle is a vehicle that uses a motor driven by a DC power source via an inverter in addition to a conventional engine as a power source. In other words, a power source is obtained by driving the engine, a DC voltage from a DC power source is converted into an AC voltage by an inverter, and a motor is rotated by the converted AC voltage to obtain a power source.

  An electric vehicle is a vehicle that uses a DC power source, an inverter, and a motor driven by the inverter as a power source.

  As a drive motor for such a hybrid vehicle or electric vehicle, a rotor (hereinafter also referred to as a rotor) is provided with a permanent magnet, and the magnetic pole generated by the permanent magnet and a stator (hereinafter also referred to as a stator) are generated. A permanent magnet type motor that rotates by a magnetic action with a rotating magnetic field, a field coil in the rotor, and a component perpendicular to the rotation axis of the magnetic field generated in the rotor by flowing a field current through the field coil, A field winding motor that rotates by a magnetic action with a rotating magnetic field generated in a stator has been studied.

  Further, in a hybrid vehicle or an electric vehicle, it has been studied to boost a DC voltage from a DC power source with a boost converter and supply the boosted DC voltage to an inverter that drives a motor.

  For example, Japanese Patent Laying-Open No. 2005-143157 (Patent Document 1) discloses a field winding motor that is provided in a vehicle and generates power, a battery, and a lift provided between the battery and the field winding motor. Disclosed is a vehicle motor control device that includes a voltage inverter and a controller that performs field control and step-up / step-down control according to the driving state of the vehicle.

According to this, the step-up / step-down inverter includes an inverter unit, a step-up / step-down unit and a capacitor. The step-up / step-down inverter supplies power from the battery to the engine starting field winding motor (starting motor), and from the step-up / down unit, the starting motor and rear wheel driving field winding motor (rear wheel driving motor). ) Is supplied to the field winding. In this case, the power supply to the field winding is controlled by turning on and off the field control circuit by the controller.
JP 2005-143157 A

  However, according to the vehicle motor control device described in Patent Document 1 described above, a field control circuit for controlling power supply to the field winding is required. Therefore, the problem that the physique of a vehicle motor control apparatus becomes large arises. These are contrary to the demand for downsizing of the apparatus body that is increasing from the viewpoint of securing the interior space of the vehicle.

  Therefore, the present invention has been made to solve such a problem, and an object of the present invention is to provide an electric motor drive device that achieves both miniaturization and higher output of the electric motor and a control method thereof. .

  According to an aspect of the present invention, an electric motor drive device is a drive device for an electric motor including a field winding and having a field pole formed by flowing a field current through the field winding. An electric motor driving apparatus receives a voltage between a power source, a converter that converts a DC voltage from the power source and outputs the voltage between the first and second power lines, and a voltage between the first and second power lines. And an inverter that converts the electric power into drive power. The converter includes a step-up switching element electrically connected between the field winding and the second power supply line. The field winding is electrically connected on the current path between the power supply and the first power supply line, and is configured such that the voltage switched by the boosting switching element is applied to both ends. The electric motor drive device further includes a field switching element connected in parallel to the field winding, and a control device that performs switching control of the step-up switching element and the field switching element. The control device includes a voltage sensor that detects a voltage output from the converter between the first and second power supply lines, a current sensor that detects a field current flowing through the field winding, a voltage command value, and a voltage sensor. The target value of the boosted current output from the converter to the first power supply line is set according to the deviation from the detected voltage, and the field is set according to the deviation between the current command value and the detected current from the current sensor. By adding the target current setting means for setting the target value of the field magnetizing current supplied to the field winding in the direction of strengthening, the target value of the field magnetizing current and the target value of the boost current, the current command Current command generating means for generating a value, and switching control means for performing switching control of the field switching element and the step-up switching element so that the detected current from the current sensor matches the current command value.

  Preferably, the switching control means uses the current command value at the predetermined control timing to match the detected current from the current sensor at the predetermined control timing with the current command value at the predetermined control timing. Terminal voltage command value generating means for generating a command value for the terminal voltage of the terminal, and a duty ratio calculation for calculating the duty ratio of the field switching element and the step-up switching element based on the generated terminal voltage command value And a control signal generating means for generating a switching control signal for switching the step-up switching element and the field switching element in accordance with the calculated duty ratio.

  Preferably, the duty ratio calculating means calculates a ratio between the current command value and the boost current using the power balance in a steady state of the converter, and based on the calculated current command value and the boost current ratio, the switching for boosting The period during which the element and the field switching element are turned off is calculated, and only the step-up switching element and the field switching element are determined based on the calculated period and the inter-terminal voltage command value. Calculate the period to be turned on.

  According to another aspect of the present invention, there is provided a control method for a motor drive device including a field winding and having a field pole formed by flowing a field current through the field winding. Drives and controls the electric motor by receiving a voltage between the first and second power supply lines and a converter that converts the DC voltage from the power supply into a voltage and outputs the converted voltage between the first and second power supply lines. An inverter for converting the power into the field, a field switching element connected in parallel to the field winding, a voltage sensor for detecting a voltage output between the first and second power supply lines from the converter, and a field magnet And a current sensor for detecting a field current flowing through the winding. The converter includes a step-up switching element electrically connected between the field winding and the second power supply line. The field winding is electrically connected on the current path between the power supply and the first power supply line, and is configured such that the voltage switched by the boosting switching element is applied to both ends. The control method sets the target value of the boost current output from the converter to the first power supply line according to the deviation between the voltage command value and the detected voltage from the voltage sensor, and detects the current command value and the detection from the current sensor. A step of setting a target value of the field magnetizing current supplied to the field winding in a direction to strengthen the field according to the deviation from the current, a target value of the field magnetizing current, and a target value of the boost current Are added to each other, and a step of generating a current command value and a step of switching control of the field switching element and the step-up switching element so that the detected current from the current sensor matches the current command value are provided.

  Preferably, the step of switching control uses the current command value at the predetermined control timing to match the detected current from the current sensor at the predetermined control timing with the current command value at the predetermined control timing. A step of generating a command value of the inter-terminal voltage of the element, a step of calculating a duty ratio of the field switching element and the step-up switching element based on the generated inter-terminal voltage command value, and the calculated duty ratio And generating a switching control signal for switching the step-up switching element and the field switching element.

  Preferably, the step of calculating the duty ratio calculates a ratio between the current command value and the boost current using the power balance in a steady state of the converter, and boosts the voltage based on the calculated current command value and the ratio of the boost current. A step of calculating a period during which the switching element for field and the switching element for field are turned off, and a step for boosting based on the calculated period for turning off the switching element for boosting element and field switching element and the inter-terminal voltage command value And calculating a period during which only the switching element is turned on and a period during which only the field switching element is turned on.

  ADVANTAGE OF THE INVENTION According to this invention, in the drive device which drives the electric motor which can variably control the amount of armature winding linkage magnetic flux, size reduction of a drive device and high output of an electric motor can be made compatible.

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

[Configuration of electric motor]
FIG. 1 is a side sectional view of an electric motor applied to an electric motor driving apparatus according to an embodiment of the present invention, and FIG. 2 is a sectional view taken along line II-II in FIG.

  Referring to FIGS. 1 and 2, electric motor 10 includes a rotating shaft 41, a rotor (rotor) 40 fixed to rotating shaft 41, and a field yoke provided on the outer periphery of stator (stator) 30. 21 and a field coil 50 are provided.

  An air gap GP is provided between the rotor 40 and the stator 30 and is arranged so as to be slightly separated in the radial direction.

  The rotor 40 includes a rotor core 43 fixed to the rotary shaft 41 and a magnet 44 provided on the outer surface of the rotor core 43.

  The rotor core 43 includes a laminated rotor core 43a formed in a cylindrical shape, and a dust rotor core 43b provided on the inner periphery of the laminated rotor core 43a. The dust rotor core 43b is made of an integral magnetic material, specifically, a powder-molded magnetic body (SMC: Soft Magnetic Composites).

  The laminated rotor core 43a is configured by laminating a plurality of electromagnetic steel plates in the axial direction. Due to a gap generated between the electromagnetic steel plates, the axial magnetic resistance is larger than the radial and circumferential magnetic resistances. Yes. Therefore, in the laminated rotor core 43a, the magnetic lines of force from the magnet are difficult to flow in the axial direction and are easy to flow in the radial direction and the circumferential direction.

  On the other hand, since the dust rotor core 43b is made of a powder molded magnetic body, the axial magnetic resistance is smaller than the axial magnetic resistance of the laminated rotor core 43a. Therefore, the lines of magnetic force easily flow in the axial direction inside the dust rotor core 43b.

  As shown in FIG. 2, a plurality of rotor teeth (first salient pole portions) 45 are formed on the outer surface of the laminated rotor core 43a at regular intervals and projecting radially outward. Has been.

  A magnet 44 is provided between the adjacent rotor teeth 45. Both the outer surface of the rotor teeth 45 and the outer surface of the magnet 44 are located on the same virtual circumference centered on the central axis of the rotating shaft 41. That is, the magnets 44 are provided so as to be adjacent to the rotor teeth 45 in the circumferential direction of the rotor 40, and are provided so that the outer peripheral surfaces are flush with each other.

  The N pole (first magnetic pole) and S pole (second magnetic pole) of the magnet 44 are arranged so as to be aligned in the radial direction of the rotor 40. In the present embodiment, the N pole of the magnet 44 is arranged outward in the radial direction of the rotor core 43, and the S pole of the magnet 44 is arranged inward in the radial direction of the rotor core 43. You may arrange | position so that it may become reverse.

  The stator 30 includes a stator core 22 formed in a hollow cylindrical shape, a plurality of stator teeth (second salient pole portions) 23 formed on the inner surface of the stator core 22 and projecting inward in the radial direction of the stator core 22; And a coil 24 wound around the stator teeth 23.

  The stator teeth 23 are formed at equal intervals in the circumferential direction. Part of the coil 24 constitutes a U-phase coil, the remaining part of the coil 24 constitutes a V-phase coil, and the remaining coil 24 constitutes a W-phase coil. The U-phase coil, the V-phase coil, and the W-phase coil have terminals at one end and are connected to inverter three-phase cables (U-phase cable, V-phase cable, and W-phase cable) (not shown). Further, the U-phase coil, the V-phase coil, and the W-phase coil are neutrally connected at the other end to one point.

  When the control device 100 (FIG. 1) receives a torque command value from an ECU (Electronic Control Unit) provided outside the motor drive device, the motor 100 outputs a torque specified by the received torque command value. The current (motor drive current) that flows through each phase of 10 is controlled. The controlled motor drive current is supplied to the coil 24 via a three-phase cable.

  Since the stator core 22 is formed by laminating a plurality of magnetic steel plates, an air gap is generated between the magnetic steel plates. Therefore, the radial and circumferential magnetic resistance of the stator core 22 is smaller than the axial magnetic resistance. Thereby, the magnetic force lines that have entered the stator core 22 are easy to flow in the circumferential direction and the radial direction of the stator core 22, and are difficult to flow in the axial direction.

  As shown in FIG. 1, the field yoke 21 is formed on the top plate portion 21 a disposed at a position spaced apart from both ends of the stator 30 and the rotor 40 in the axial direction, and the peripheral portion of the top plate portion 21 a. A cylindrical side wall portion 21b and a cylindrical projection 21c formed on the top plate portion 21a are provided.

  A through hole 21d is formed in the central portion of the top plate portion 21a, and the rotary shaft 41 is inserted into the through hole 21d through a bearing 46. The side wall portion 21 b is fixed to the outer surface of the stator core 22.

  The field yoke 21 is made of an integral magnetic material, specifically, a powder-molded magnetic body (SMC) that is a three-dimensional fully isotropic material. For this reason, the magnetic resistance in the axial direction of the field yoke 21 is made smaller than the magnetic resistance in the axial direction of the stator core 22.

  The protruding portion 21c is formed on the inner surface of the top plate portion 21a and protrudes toward the axial end portion of the dust rotor core 43b. And the edge part of the protrusion 21c and the edge part of the dust rotor core 43b are adjoining so that a magnetic force line may not be interrupted between the edge part of the protrusion 21c and the edge part of the powder rotor core 43b.

  For this reason, it reaches the field yoke 21 from the surface of the magnet 44 via the air gap GP and the stator core 22, flows in the field yoke 21 in the axial direction, enters the dust rotor core 43 b from the protrusion 21 c, and A magnetic circuit (first magnetic circuit) that returns to the S pole can be formed.

  In this magnetic circuit, the radial magnetic resistance of the stator core 22 is kept small, the magnetic resistance in the field yoke 21 is kept small, and the magnetic resistance of the dust rotor core 43b is also kept small. Therefore, the loss of magnetic energy can be kept small.

  In addition, in the example shown in FIG. 1, although the cylindrical protrusion 21c is formed in the field yoke 21, you may provide in the edge part of the dust rotor core 43b.

  The field coil (winding) 50 is wound around the outer peripheral surface of the protrusion 21c. By passing a current through the field coil 50, for example, the N pole magnetism can be provided on the end side of the protrusion 21c, and the S pole magnetism can be provided on the side wall 21b. Alternatively, it is possible to give the south pole magnetism to the end side of the protrusion 21c and allow the side wall portion 21b to have north pole magnetism. In the present embodiment, the field coil 50 is provided on the protrusion 21c of the field yoke 21, but is not limited to this position and may be provided on the field yoke 21. Here, the fact that the field coil 50 is provided in the field yoke 21 is not limited to the case where the field coil 50 is in contact with the surface of the field yoke 21, and the flow of magnetic lines of force in the field yoke 21. If it is a controllable level, the case where it is separated from the surface of the field yoke 21 is included.

  The operation of the electric motor 10 configured as described above will be described with reference to FIGS. 3 and 4. 3 is a side sectional view of the electric motor 10 in a state where the current of the field coil 50 shown in FIG. 1 is supplied, and FIG. 4 is a sectional view taken along line IV-IV in FIG.

  Referring to FIG. 3, magnetic field lines mt <b> 4 are generated by passing a current through field coil 50. The magnetic force line mt4 passes through the top plate portion 21a of the field yoke 21 and enters the stator core 22 from the side wall portion 21b. The magnetic lines of force mt4 enter the rotor core 43 through the air gap GP and advance in the rotor core 43 in the axial direction. Thereafter, the magnetic force line mt4 enters the field yoke 21 from the axial end surface of the rotor core 43 via the end surface of the protrusion 21c.

  By generating such a magnetic circuit, the protrusion 21c of the field yoke 21 has S pole magnetism, and the side wall 21b of the field yoke 21 has N pole magnetism.

  In FIG. 4, stator teeth 23 a are arranged on the end side of the rotation direction P of the rotor 40 among the end portions of the magnet 44, and the central portion in the circumferential direction of the outer main surface of the magnet 44 is the stator. It is located on the rear side in the rotational direction P at the circumferential center of the end surface of the tooth 23a. An end surface on the inner diameter side of the stator teeth 23a is an S pole.

  For this reason, the magnetic lines of force mt1 to mt4 that emerge from the outer main surface of the magnet 44 are inclined toward the front side in the rotational direction P toward the outer side in the radial direction, and reach the end surface of the stator teeth 23a. Thus, since the magnetic path of the magnetic force lines mt1 to mt3 between the magnet 44 and the stator teeth 23a is inclined and long, stress is applied to the rotor 40 so that the magnetic path is the shortest. That is, the magnet 44 is pulled toward the stator teeth 23a.

  Stator teeth 23b are provided on the rear side in the rotational direction P of the rotor 40 with respect to the stator teeth 23a. The stator teeth 23 b are opposed to the vicinity of the central portion of the magnet 44. The end surface on the inner diameter side of the stator teeth 23 b is an N pole and repels the magnet 44.

  For this reason, the magnetic force lines mt <b> 1 to mt <b> 3 that have entered the stator core 22 from the stator teeth 23 a flow in the stator core 22 in the circumferential direction. At this time, as described above, the inner wall surface of the side wall portion 21b becomes an N pole by flowing a current through the field coil 50. Therefore, the magnetic lines of force mt <b> 1 to mt <b> 3 from the magnet 44 proceed along the circumferential direction of the stator core 22 when entering the stator core 22 from the end face of the stator teeth 23 a. That is, the magnetic lines of force mt <b> 1 to mt <b> 3 flow in the stator core 22 in the radial direction after reaching the stator teeth 23 a and are prevented from reaching the field yoke 21.

  The stator teeth 23c are provided on the rear side in the rotational direction P of the rotor 40 with respect to the stator teeth 23b, and the end face on the inner diameter side is an N pole. The stator teeth 23c are opposed to the rotor teeth 45a.

  Here, since the outer surface of the magnet 44 adjacent to the rotor teeth 45a is N-pole, the magnetic lines of force mt1 to mt3 from the end face of the stator teeth 23c toward the rotor teeth 45a are affected by the N-pole of the magnet 44. Then, it flows toward the rotor teeth 45a so as to incline backward in the rotation direction P. Then, the rotor teeth 45a are satisfactorily drawn toward the stator teeth 23c so that the path length becomes the shortest.

  As described above, the magnetic lines of force mt1 to mt3 reach the stator teeth 23a from the magnet 44 via the air gap GP and pass through the stator core 22 in the circumferential direction, and then, from the stator teeth 23c via the air gap GP, the laminated rotor core 43a. The magnetic circuit K1 is formed to reach the inside and return to the magnet 44 again.

  On the other hand, in a state in which no current is supplied to the field coil 50, a part of the magnetic force lines mt1 to mt3 (for example, the magnetic force line mt3) from the magnet 44 flows in the stator core 22 in the radial direction after reaching the stator teeth 23a. The field yoke 21 is reached. The magnetic force line mt3 forms a magnetic circuit K2 (not shown) that passes through the field yoke 21 in the axial direction, enters the dust rotor core 43b from the projection 21c, and returns to the magnet 44 again.

  That is, by passing a current through the field coil 50, it is possible to suppress the magnetic lines of force mt1 to mt3 emitted from the magnet 44 from passing through the magnetic circuit K2, and to control the magnetic lines of force mt1 to mt3 through the magnetic circuit K1. . Thereby, since the ratio of the magnetic flux amount that passes through the magnetic circuit K1 that greatly contributes to the generation of torque among the constant magnetic flux amount generated from the magnet 44 can be increased, a large torque can be obtained.

  Further, as shown in FIG. 4, the magnetic field line mt4 generated by the field coil 50 is a part of the magnetic circuit K1, passes through a path from the stator teeth 23c to the rotor teeth 45a, and then reaches the dust rotor core 43b. . For this reason, the lines of magnetic force mt4 also contribute to the generation of torque.

As described above, by applying a current to the field coil 50, the “strong field control” is performed on the electric motor 10. FIG. 5 is a diagram illustrating the relationship between the torque and the rotational speed of the electric motor 10. In the following, the current supplied to the field coil 50 is also referred to as “field current”, and the field current is expressed using the symbol _If .

In FIG. 5, a curve k1 shows the output characteristics of the electric motor 10 in a state where no current is supplied to the field coil 50 (field current I _f = 0). On the other hand, the curve k2 shows the output characteristic of the motor in a state where the current is supplied to the field coil 50 (field current I _f ≠ 0).

  As shown in FIG. 5, it can be seen that the torque is increased in a wide range from a low rotation speed to a high rotation speed by applying a current to the field coil 50 and performing strong field control on the electric motor 10. In particular, a large torque is obtained in a region where the rotational speed is low.

  It should be noted that the “weakening field control” can be applied to the electric motor 10 by reversing the direction of the current flowing through the field coil 50. In this case, by passing a current through the field coil 50, the ratio of the amount of magnetic flux passing through the magnetic circuit K1 is reduced.

  Further, according to the present embodiment, of the outer peripheral surface of the rotor 40, the surface of the magnet 44 functions as a region for generating magnetic lines of force, and the rotor tooth 45 functions as a region for capturing the generated lines of magnetic force. Yes. And since the magnet 44 and the rotor tooth 45 are extended over the axial direction of the rotor 40, the outer peripheral surface of the rotor 40 is comprised from the surface of the magnet 44, and the surface of the rotor teeth 45. FIG. Therefore, substantially the entire outer peripheral surface of the rotor teeth 45 can be made to function as an output region for magnetic lines of force and an intake region for magnetic lines of force, so that the utilization efficiency of the outer peripheral surface of the rotor 40 can be improved. As a result, since the required amount of magnetic flux can be taken in and out even with a small rotor 40, the rotor 40 itself can be made compact.

[Configuration of electric motor drive device]
As described above, according to this embodiment, the field control of the electric motor 10, by adjusting the amount of magnetic flux passing through the magnetic flux and the magnetic circuit K2 through the magnetic circuit K1 by the field current I _f flowing through the field coil 50 Thus, it is performed by adjusting the armature winding flux linkage.

However, in order to realize such field control, it is necessary to newly install a power supply circuit for supplying the field current _If to the field coil 50. The installation of the power supply circuit leads to problems such as increasing the size of the electric motor drive device and increasing the device cost.

  Therefore, the electric motor drive device according to the present embodiment also uses the reactor, which is a component of the power conversion device for converting the voltage from the power source into the drive voltage of the electric motor 10, as the field coil 50 as described below. The configuration is as follows.

FIG. 6 is a schematic block diagram of the electric motor drive device according to the embodiment of the present invention.
Referring to FIG. 6, electric motor drive device 1000 includes battery B, snubber capacitor C1, boost converter 120, inverter 140, smoothing capacitor C2, voltage sensors 110 and 130, and current sensors 112 and 240. Prepare.

  The electric motor 10 has a configuration shown in FIGS. 1 and 2. That is, the electric motor 10 includes a rotor fixed to the rotating shaft, a field yoke provided on the outer periphery of the stator, and a field coil 50.

  In the present embodiment, electric motor 10 is a drive motor for generating torque for driving drive wheels of a hybrid vehicle or an electric vehicle. The electric motor 10 is a motor that has a function of a generator driven by an engine and that operates as an electric motor for the engine and can start the engine, for example.

The battery B is made of a secondary battery such as nickel metal hydride or lithium ion. In the present embodiment, a configuration in which the battery B configured by a secondary battery is a “DC power supply” will be described. However, instead of the battery B, a power storage device such as an electric double layer capacitor may be applied. It is. Snubber capacitor C 1 is connected between power supply line 106 and ground line 105. Voltage sensor 110, DC voltage output from battery B (hereinafter also battery voltage referred to) detecting the E _B, and outputs the detected battery voltage E _B to the control unit 100.

  Boost converter 120 includes a reactor L1 and power semiconductor switching elements (hereinafter also simply referred to as “switching elements”) Q1 and Q2 that are controlled to be switched.

Reactor L1 has one end connected to power supply line 106 of battery B and the other end connected to a connection node of switching element Q1 and switching element Q2. In the present embodiment, reactor L1 is wound around field yoke 21 (FIG. 1) of electric motor 10. That is, the reactor L1 is applied with the voltage switched by the switching elements Q1 and Q2, and constitutes the field coil 50 in the electric motor 10. Accordingly, the current flowing through the reactor L1 (hereinafter, also referred to as reactor current) I _f corresponds to a field current I _f to be supplied to the field coil 50 described above. Current sensor 112 detects a reactor current (field current) _If and outputs the detected reactor current _If to control device 100.

  Switching elements Q1, Q2 are connected in series between power supply line 107 and ground line 105. Switching elements Q1 and Q2 are turned on / off by switching control signals SE1 and SE2 from control device 100.

  In the embodiment of the present invention, an IGBT (Insulated Gate Bipolar Transistor), a power MOS (Metal Oxide Semiconductor) transistor, a power bipolar transistor, or the like can be used as the switching element. Anti-parallel diodes D1, D2 are arranged for switching elements Q1, Q2.

Smoothing capacitor C <b> 2 is connected between power supply line 107 and ground line 105. Voltage sensor 130 detects voltage V _DC (corresponding to the output voltage of boost converter 120) across smoothing capacitor C2, and outputs the detected output voltage V _DC to control device 100.

  The DC voltage side of inverter 140 is connected to boost converter 120 through power supply line 107 and ground line 105.

  Inverter 140 includes U-phase arm 150, V-phase arm 160, and W-phase arm 170 provided in parallel between power supply line 107 and ground line 105. Each phase arm is composed of a switching element connected in series between power supply line 107 and ground line 105. For example, U-phase arm 150 includes switching elements Q5 and Q6, V-phase arm 160 includes switching elements Q7 and Q8, and W-phase arm 170 includes switching elements Q9 and Q10. Antiparallel diodes D5 to D10 are connected to switching elements Q5 to Q10, respectively. Switching elements Q5 to Q10 are turned on / off by a switching control signal PWMI from control device 100.

  An intermediate point of each phase arm is connected to each phase end of each phase coil of electric motor 10. That is, the electric motor 10 is a three-phase synchronous motor, and is configured such that one end of three coils of U, V, and W phases is commonly connected to a midpoint. The other end of the U-phase coil is at the midpoint between the switching elements Q5 and Q6, the other end of the V-phase coil is at the midpoint between the switching elements Q7 and Q8, and the other end of the W-phase coil is at the midpoint between the switching elements Q9 and Q10. Each is connected. Inverter 140 performs bidirectional power conversion between boost converter 120 and electric motor 10 by on / off control (switching control) of switching elements Q5 to Q10 in response to switching control signal PWMI from control device 100.

  Specifically, inverter 140 can convert a DC voltage received from power supply line 107 into a three-phase AC voltage in accordance with switching control by control device 100, and output the converted three-phase AC voltage to electric motor 10. Thereby, the electric motor 10 is driven to generate a designated torque.

  Further, the inverter 140 converts a three-phase AC voltage generated by the motor 10 into a DC voltage according to switching control by the control device 100 during regenerative braking of the hybrid vehicle or the electric vehicle on which the motor driving device 1000 is mounted, and the conversion is performed. A DC voltage can be output to the power supply line 107.

  Note that regenerative braking here refers to braking with regenerative power generation when the driver operating the hybrid vehicle or electric vehicle performs footbrake operation, or while not operating the footbrake, Including decelerating (or stopping acceleration) the vehicle while regenerating power.

  The electric motor 10 is provided with a current sensor 240. Since the sum of instantaneous values of the three-phase currents Iu, Iv, and Iw is zero, the current sensor 240 detects two-phase motor currents (for example, the U-phase current Iu and the W-phase current Iw) as shown in FIG. It is enough to arrange it to do. The motor currents Iu and Iw detected by the current sensor 240 are input to the control device 100. Further, control device 100 receives input of torque command value TR of motor 10 and motor rotational speed MRN as motor commands.

  In electric motor drive device 1000 having the above configuration, boost converter 120 is configured as a chopper type circuit including a reactor L1 electrically connected on a current path formed between power supply lines 106 and 107. A voltage switched by turning on / off the switching elements Q1, Q2 is applied to both ends of the reactor L1.

  Furthermore, the reactor L1 forms a field coil 50 (FIG. 1) by being wound around the field yoke 21 of the electric motor 10. Therefore, when the current flows through reactor L1, field control of electric motor 10 as described above is performed.

  As described above, the reactor L1 of the boost converter 120 is also used as the field coil 50 of the electric motor 10, so that the current flowing between the power supply lines 106 and 107 is supplied to the field coil 50. Therefore, it is not necessary to newly provide a power supply circuit for supplying a current to the field coil 50, so that the motor drive device 1000 can be prevented from being increased in size and the device cost.

On the other hand, however, in this configuration, when the boosting operation is performed by the boosting converter 120, current is always driven to the field coil 50, so that the field control of the electric motor 10 is necessarily performed. Then, the field current I _f at this time, since the magnitude dependent on the step-up ratio in step-up converter 120, making it from that always matches the current value required to adjust the armature flux linkage amount described above Absent.

  That is, in the configuration in which the reactor L1 is also used as the field coil 50, there arises a problem that the field control of the electric motor 10 and the boost operation control (boost control) cannot be executed independently of each other. As a result, there is a possibility that the drive control of the electric motor 10 cannot be performed so as to follow the required output to the electric motor 10 that changes as appropriate according to the driving state of the vehicle.

  Therefore, the electric motor drive device according to the present embodiment is configured to further include a switching element Q3 and a diode D3 connected in parallel to the reactor L1, as shown in FIG. By turning on switching element Q3 in this configuration, a current path is formed so that a direct current flows through switching element Q3 and diode D3 in accordance with the electric power stored in reactor L1.

  In the configuration of FIG. 6, the switching element Q1 of the boost converter 120 corresponds to the “boost switching element” in the present invention, and the switching element Q3 corresponds to the “field switching element” in the present invention.

  In the present embodiment, as described below, control device 100 executes switching control of switching element Q3 in conjunction with switching control of switching elements Q1 and Q2 during the power running operation of electric motor 10. Thereby, the boost control in boost converter 120 and the field control of electric motor 10 can be executed independently of each other.

[Control structure of motor drive unit]
A control device 100 including an electronic control unit (ECU) includes a microcomputer, a RAM (Random Access Memory), and a ROM (Read Only Memory) (both not shown). The control device 100 switches the switching control signal SE1 for switching control of the boost converter 120 and the inverter 140 so that the electric motor 10 operates in accordance with a motor command input from a host electronic control unit (ECU) according to a predetermined program process. , SE2 (boost converter 120), and PWMI (inverter 140). That is, control device 100 controls the power conversion operation by boost converter 120 and inverter 140.

Further, control device 100 generates a switching control signal SE3 for switching control of switching element Q3 connected in parallel to reactor L1, so that field current _If is supplied to field coil 50 of electric motor 10. . That is, the control device 100 performs field control of the electric motor 10.

  In the present embodiment, the upper electronic control unit (ECU) of the control device 100 calculates the driving force required for the vehicle based on the accelerator opening degree opened by the driver's accelerator operation and the like. Based on the required driving force, the required output (torque × rotational speed) of the electric motor 10 is calculated.

When the control device 100 receives the required output of the electric motor 10 from the ECU, the control device 100 derives a voltage command V _DC ^* that is a target value of the output voltage V _DC based on the required output, and according to the derived voltage command V _DC ^* . Thus, a target value (target boost current) I _boost ^* of a current (hereinafter also referred to as a boost current) I _boost flowing from the power supply line 107 to the smoothing capacitor C2 is set.

Further, the control device 100 determines a target value (target field) of a current (hereinafter also referred to as field magnetizing current) I _Fref that is supplied to the field coil 50 in a direction that strengthens the field according to the reactor current _If. Magnetizing current) I _Fref ^* is set. Then, a current (= I _boost ^* + I _Fref ^* ) obtained by synthesizing the set target boost current I _boost ^* and the target field magnetizing current I _Fref ^* is a reactor that is a target value of the reactor current _If passing through the reactor L1. Set to current command _If ^* .

Then, the control unit 100, the reactor current _{I f} from the current sensor 112 so as to follow the reactor current command _I ^{f *,} executes a feedback control of the reactor current _{I f.} Control of reactor current _If is realized by switching control of switching elements Q1 to Q3 as described below.

FIG. 7 is a diagram for explaining switching control of the switching elements Q1 to Q3 by the control device 100. FIG. The switching control is performed with pattern (i) to pattern (iii) in the figure as one control cycle. FIG. 8 is a timing chart of the reactor current (field current) _If and the boost current _Iboost in one cycle of the switching control.

Referring to pattern (i), first, switching element Q1 is turned on and switching elements Q2 and Q3 are turned off, so that a direct current is supplied from battery B, reactor L1 as indicated by arrows in the figure. And the circuit which consists of switching element Q1 flows in the direction from the battery B to the switching element Q1. During this period, electric power is accumulated in the reactor L1. Therefore, as shown in FIG. 8, the reactor current _If increases in the period (corresponding to the period T1). At this time, reactor current _If increases to a value obtained by adding field magnetizing current I _Fref and boost current I _boost to motor output current I _DCout supplied from power supply line 107 to inverter 140.

Next, as shown in the pattern (ii), all of the switching elements Q1 to Q3 are turned off by turning off the switching element Q1. Then, in accordance with the electric power stored in reactor L1, input current I _DCin is input to power supply line 107 from reactor L1 via antiparallel diode D2. At this time, the smoothing capacitor C2 includes a field magnetizing current I _Fref and a boosting current I according to the voltage difference between the output voltage between the power supply line 107 and the ground line 105 and the voltage V _DC across the smoothing capacitor C2. _{A boost} combined current flows. Thus, the voltage across the smoothing capacitor C2 (i.e., the output voltage of boost converter 12) V _DC is boosted to a DC voltage (battery voltage) E voltage higher than _B from the battery B. Note that the boosted current _Iboost flowing through the smoothing capacitor C2 gradually decreases as shown in the period T2 in FIG. Accordingly, the reactor current _If also gradually decreases.

Finally, as shown in pattern (iii), when switching element Q3 is turned on and switching elements Q1 and Q2 are turned off, a closed circuit consisting of reactor L1, switching element Q3, and diode D3 is connected from reactor L1 to switching element Q3. The field increasing current I _Fref flows in the direction of. In this case, as shown in the period T3 in FIG. 8, the reactor current _If gradually decreases as the remaining power accumulated in the reactor L1 decreases. Further, the diode D2 is not energized, and the boost current _Iboost is reduced to 0A.

By repeating such patterns (i) to (iii), boost converter 120 performs a boost operation. Then, a current obtained by averaging the boost current I _boost from the period T1 to the period T3 (average boost current I _boostav ) flows from the boost converter 120 to the smoothing capacitor C2. That is, the average boosted current I _boostav is a value obtained by dividing the boosted current I _boost in the period T2 by one control cycle (= period T1 + period T2 + period T3).

Furthermore, in reactor L1, a current (average reactor current I _fav ) that is an average of reactor current _If in each period from period T1 to period T3 flows. Then, field control of the electric motor 10 is performed in accordance with the average reactor current I _fav .

That is, the average boost current I _boostav and the average reactor current I _fav can be controlled independently by changing the ratio of the period T1, the period T2, and the period T3 in one control cycle. According to this, in the configuration in which the reactor L1 of the boost converter 120 is also used as the field coil of the electric motor 10, by changing the ratio according to the required output to the electric motor 10, the boost control and the field control of the electric motor 10 are performed. It becomes possible to control them independently of each other. As a result, a large torque is obtained by the strong field in the low rotation range, and high efficiency is realized by the boost control in the high rotation range, so that the motor drive device 1000 can be suppressed while preventing an increase in size and cost. High output of 10 can be realized.

[Switching control of switching elements]
Next, a control structure for realizing the switching control of switching elements Q1 to Q3 described in FIGS. 7 and 8 will be described in detail.

  FIG. 9 is a circuit diagram for explaining a circuit operation state of the motor drive device realized by switching control of the switching elements Q1 to Q3.

  When the circuit parameters of boost converter 120 are determined as shown in FIG. 9, the circuit operation states in the three patterns (i) to (iii) described in FIG. 7 can be represented by the following circuit equations.

  Specifically, the circuit operation state when the pattern (i) in FIG. 7, that is, only the switching element Q1 among the switching elements Q1 to Q3 is turned on, is expressed by the following equation.

  Next, the pattern (ii) in FIG. 7, that is, the circuit operation state when all of the switching elements Q1 to Q3 are turned off, changes as the following expression.

Thereby, the inter-terminal voltage V of the switching element Q1 is boosted from 0 V to the output voltage _VDC of the boost converter 120.

  Finally, the pattern (iii) of FIG. 7, that is, the circuit operation state when only the switching element Q3 among the switching elements Q1 to Q3 is turned on is expressed by the following equation.

In this case, since the flow through the closed circuit including the reactor L1 and the switching element Q3 reactor current I _f, the terminal voltage V of the switching element Q1 drops to the battery voltage E _B.

Here, regarding reactor current _If and output voltage V _DC of boost converter 120, as described above, the ratio of the on-time of switching elements Q1 and Q3 in one control cycle, that is, the duty ratio of switching elements Q1 and Q3 is set as follows. By controlling, it can be made to correspond to reactor current command _If ^* and voltage command _VDC ^* , respectively.

  Such control of the duty ratios of the switching elements Q1 and Q3 can be realized, for example, by configuring the control device 100 with the control structure shown in FIG.

FIG. 10 is a block diagram illustrating a control structure of the control device 100 of FIG.
Referring to FIG. 10, control device 100 includes subtracters 200 and 202, adder 204, PI calculation units 206 and 208, and switching control unit 210.

The subtractor 200 calculates a voltage deviation ΔV _DC of the output voltage V _DC from the voltage sensor 130 with respect to the voltage command V _DC ^* and outputs the voltage deviation ΔV _DC to the PI calculation unit 206. The PI calculation unit 206 performs a PI calculation with a predetermined gain on the voltage deviation ΔV _DC to obtain a control deviation, and generates a target value (target boost current) I _boost ^* of the _boost current I _boost according to the control deviation.

Subtractor 202 calculates and outputs the reactor current command _I ^{f *} for the current deviation [Delta] I _f the reactor current _{I f} from the current sensor to the PI calculation portion 208. PI calculating unit 208 obtains the control deviation by performing the PI calculation using a predetermined gain for current deviation [Delta] I _f, the target value of the field磁増current _{I Fref} according to the control deviation (target field磁増_{current) I Fref} ^{* Is} generated.

The adder 204, by synthesizing the generated target voltage boosting current _{I boost} ^* and target field磁増current _{I Fref} ^*, generates a current command _I ^{f *} of the reactor current _{I f.} The generated current command I _f ^* (= I _boost ^* + I _Fref ^* ) is sent to the switching control unit 210.

The switching control unit 210, based on the reactor current command _I ^{f *,} derives the on-time _{T Q1, T Q3} of the switching elements Q1, Q3 in the first control cycle by a method described later. Then, the switching control unit 210, the switching element Q1 in accordance with the on-time _{T Q1, T Q3} was its derivation, Q3 and to turn on respectively, it generates switching control signals SE1, SE3. The switching elements Q1, Q2 by switching control according to the generated switching control signals SE1, SE3, the reactor L1, flows reactor current _{I f} in accordance with a reactor current command _I ^{f *.} Further, the output voltage V _DC according to the voltage command V _DC ^* is applied to the inverter 140 (not shown).

  Next, specific control processing in the control structure of FIG. 10 will be described. In the present embodiment, a case will be described in which control device 100 executes control processing using a digital signal processor (DSP).

  In FIG. 10, the instantaneous voltage equation of boost converter 120 is represented by equation (1).

Here, in performing the control process using the DSP, the reactor current I _f (t), the output voltage V _DC (t), and the voltage V (t) between the terminals of the switching element Q1 in the equation (1) are as follows: under a predetermined sampling period T _S, it is assumed that the relationship shown in the timing chart of FIG. 11 between the arbitrary control sample point m is satisfied.

In this relationship, the battery voltage E _B (t), the reactor current _If (t), the voltage V (t) between the terminals of the switching element Q1 and the current differential dI / dt are approximated as follows.

That is, battery voltage E _B (t) and reactor current I _f (t) are battery voltage E _B (m−1) and reactor current I _f (m−1) at sample point (m−1), respectively. Approximated. The inter-terminal voltage V (t) of the switching element Q1 is approximated by an average voltage V (m−1) between the sample point m and the sample point (m−1). Furthermore, the current differential dI / dt is approximated by an average current between the sample point m and the sample point (m−1).

  By using these approximations, the instantaneous voltage equation of equation (1) can be rewritten as equation (2).

Here, as described above, the field control of the step-up control and the motor 10, both can be performed by controlling so as to match the reactor current I _f the reactor current command I _f ^*. Hereinafter, control of reactor current _If executed by the control structure according to the present embodiment will be described.

First, a method for generating the reactor current command _If ^* will be described. Next, a method for controlling the reactor current _If for realizing the generated reactor current command _If ^* will be described. Finally, a method for generating the switching control signals SE1, SE3 in the control of the reactor current _If will be described.

(1) As mentioned in reactor current command _I ^{f *} generation method Figure 10, the reactor current command _I ^{f *} is the target boost current _{I boost} ^* and target field磁増current _{I Fref} ^* synthesized in current . The target boost current I _boost ^* and the target field magnetizing current I _Fref ^* can be generated by the following methods, respectively.

Specifically, the target boost current I _boost ^* (m) at the sample point m is equal to the voltage deviation ΔV _DC (m−2) with respect to the voltage command V _DC ^* of the output voltage V _DC at the sample point (m−2).

On the other hand, it can be generated by performing PI calculation with a predetermined gain according to the equation (4).

However, KVP and KVI indicate a proportional gain and an integral gain, respectively.
Further, the target field increasing current I _Fref ^* (m) at the sample point m is the current deviation ΔI _f (m) of the reactor current _If at the sample point (m−2) with _{respect to} the reactor current command I _f ^* .

On the other hand, it can be generated by performing PI calculation with a predetermined gain according to the equation (6).

Here, KIP and KII indicate a proportional gain and an integral gain, respectively.
Finally, by obtaining the sum of the target boost current I _boost ^* (m) and the target field magnetizing current I _Fref ^* (m) calculated by the equations (4) and (6), respectively, at the sample point m Reactor current command _If ^* can be generated.

(2) When the reactor current _I reactor current command at the sample point m by the method shown in _f of the control method described above (1) _I ^f * (m) is generated, the reactor at the sampling point m current _I f (m ) Is controlled to match the reactor current command _If ^* (m).

In this current control, the reactor current _If (m) in the above formula (2) is replaced with the reactor current command _If ^* (m) as feedforward compensation. By using the predicted value, the stability of the control is ensured even if there is a disturbance in the output of the current sensor 112.

  Further, the inter-terminal voltage V (m−1) of the switching element Q1 is calculated by the following equation (8).

Here, in order to control the reactor current _If at the sample point m, the calculation of the equation (8) must be completed by the sample point (m−1) at the sample point (m−1). It is impossible to detect the reactor current I _f (m−1) at the point (m−1).

Therefore, along with replacing the m of formula (2) to (m-1), by replacing the V between models terminal voltage _{V M,} the sample points (m-1) in the reactor current _I f (m-1) The estimated value I _fe (m−1) is calculated using the following equation (9).

Then, using the estimated value I _fe (m−1) of the reactor current, the above equation (8) can be rewritten as the equation (10).

According to the equation (10), the voltage command V ^* (m−1) of the inter-terminal voltage V (m−1) of the switching element Q1 is set to V _M (m−1) and the terminal of the switching element Q1 The reactor current _If can be made to follow the reactor current command _If ^* by performing switching control of the switching elements Q1 to Q3 so that a voltage corresponding to the voltage command V ^* (m-1) is generated in the meantime. It becomes possible.

(3) Generation Method of Switching Control Signals SE1 and SE3 Finally, the switching converters Q1 to Q3 according to the voltage command V ^* (m−1) set in (2) above will be described with reference to the boost converter described above. By using the relationship between the circuit operation state of 120 and the voltage V between the terminals of the switching element Q1, the switching control signals SE1 and SE3 can be generated.

  That is, the inter-terminal voltage V (t) of the switching element Q1 transitions between three voltage levels as shown below according to the on / off states of the switching elements Q1 and Q3.

  The switching elements Q1 and Q3 are turned on when the switching control signals SE1 and SE3 are “1”, and are turned off when the switching control signals SE1 and SE3 are “0”.

Therefore, when the on-time of the switching element Q1 is defined as T _Q1 (m−1) and the on-time of the switching element Q3 is defined as T _Q3 (m−1), the voltage V (m−1) between the terminals of the switching element Q1. ) Can be expressed by equation (11).

However, T _Q1 + T _Q3 ≦ T _s . T _Q2 is a remaining time (= T _s −T _Q1 −T _Q3 ) obtained by subtracting the sum of the ON times of the switching elements Q1 and Q3 from one control cycle T _s .

According to this, the voltage V (m−1) between the terminals of the switching element Q1 represented by the expression (11) matches the voltage command V ^* (m−1) described above so that the switching elements Q1 and Q3 By obtaining the on times T _Q1 (m−1) and T _Q3 (m−1), respectively, the reactor current I _f (m) can be made to follow the reactor current command I _f ^* (m).

However, as apparent from the equation (11), simply determining the voltage command V ^* (m−1) results in infinite combinations of the on-times T _Q1 and T _Q3 of the switching elements Q1 and Q3. It is impossible to determine uniquely. That is, there are two degrees of freedom in determining the ON times T _Q1 and T _Q3 of the switching elements Q1 and Q3.

Therefore, in order to uniquely determine the ON times T _Q1 and T _Q3 of the switching elements Q1 and Q3, a constraint based on the relationship of the power balance in the boost converter 120 is imposed on the above equation (11). .

  That is, in boost converter 120, the relationship of Expression (12) is established between input power and output power.

Assuming that this relational expression holds even in a transient state, the target boost current I _boost ^* (m−1) and the voltage command V _DC ^* (m−1) determined in the above (1) are _expressed in the expression (12). By substituting, the input current I _DCin ^* (m−1) is derived.

This input current I _DCin (m−1) is a current that is input to the power supply line 107 when both of the switching elements Q1 and Q3 are turned off, and the magnitude of the input current I _DCin (m−1) with respect to the reactor current _{If is} an expression ( 14).

Therefore, by _substituting the input current I _DCin ^* (m−1) derived in the equation (13) and the reactor current command I _f (m−1) ^* determined in the above (1) into the equation (14), A target value T _Q2 ^* of time T _Q2 at which all of switching elements Q1 and Q3 are turned off is determined. Therefore, using Equation (11), the target values T _Q1 ^* and T _Q2 ^* of the on-times T _Q1 and T _Q2 can be uniquely determined.

Figure 12 shows an operation waveform diagram of the target value T _{Q1 ^*,} the voltage between the terminals of the switching element Q1 of the case of performing the PWM control in accordance with T _Q2 ^* V and reactor current I _f ON determined by the method described above time . In FIG. 12, the PWM control shows switching control signals SE1 and SE3 generated when a triangular wave signal is used as the carrier signal.

  As described above, in the electric vehicle equipped with the electric motor drive device according to the present embodiment, in the configuration in which reactor L1 of boost converter 120 is used as field coil 50 of electric motor 10, step-up control and field control of electric motor 10 are performed. Can be performed independently. As a result, a large torque can be obtained in the low rotation range (that is, the low vehicle speed range), and the motor can be driven with high efficiency in the high rotation range (that is, the high vehicle speed range). As a result, the drive device can be reduced in size, and the driving performance of the vehicle can be improved by increasing the output of the electric motor.

  In the electric motor 10 described above, the magnet is provided on the outer surface of the rotor. However, the present invention is not limited to this, and the magnet may be embedded in the rotor. That is, the electric motor drive device according to the present invention can be applied not only to SPM (Surface Permanent Magnet) but also to IPM (Interior Permanent Magnet). In the rotor configured as described above, both the magnet torque (the attractive repulsion force between the permanent magnet and the coil) and the reluctance torque (the force that straightens the bending of the magnetic field line = the force that the coil attracts the iron) are effectively used. be able to.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a sectional side view of the electric motor applied to the electric motor drive device which concerns on embodiment of this invention. It is sectional drawing in the II-II line of FIG. It is a sectional side view of the electric motor in the state in which the current of the field coil shown in FIG. 1 was supplied. It is sectional drawing in the IV-IV line of FIG. It is a figure which shows the relationship between the torque of an electric motor, and rotation speed. It is a schematic block diagram of the electric motor drive device according to the embodiment of the present invention. It is a figure for demonstrating switching control of the switching element by a control apparatus. 6 is a timing chart of a reactor current and a boost current in one cycle of switching control. It is a circuit diagram for demonstrating the circuit operation state of the electric motor drive device implement | achieved by switching control of a switching element. It is a block diagram explaining the control structure of the control apparatus of FIG. It is a figure for demonstrating the specific control processing in the control structure of FIG. FIG. 7 is an operation waveform diagram of a voltage between terminals of a switching element Q1 and a reactor current when PWM control is performed according to a determined target value of on-time.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Electric motor, 12 Boost converters, 21 Field yoke, 21a Top plate part, 21b Side wall part, 21c Protrusion part, 21d Through-hole, 22 Stator core, 23, 23a-23c Stator teeth, 24 Coils, 30 Stator, 40 Rotor, 41 Rotating shaft, 43 rotor core, 43a laminated rotor core, 43b dust rotor core, 44 magnet, 45, 45a rotor teeth, 46 bearing, 50 field coil, 100 controller, 105 ground line, 106, 107 power line, 110, 130 voltage Sensor, 112, 240 Current sensor, 120 Boost converter, 140 Inverter, 150 U-phase arm, 160 V-phase arm, 170 W-phase arm, 200, 202 Subtractor, 204 Adder, 206, 208 PI operation unit, 210 switch Grayed controller, 1000 electric motor drive device, B battery, C1 snubber capacitor, C2 smoothing capacitor, D1 to D8 diode, L1 reactor, Q1 to Q3, Q5～Q10 switching element.

Claims (6)

A motor drive device including a field winding and having a field pole formed by passing a field current through the field winding,
Power supply,
A converter for converting a DC voltage from the power source to output between the first and second power source lines;
An inverter that receives a voltage between the first and second power supply lines and converts the electric power to drive and control the electric motor;
The converter includes a step-up switching element electrically connected between the field winding and the second power supply line,
The field winding is electrically connected on a current path between the power supply and the first power supply line, and is configured such that a voltage switched by the boosting switching element is applied to both ends.
The motor driving device is
A field switching element connected in parallel to the field winding;
A control device for switching control of the step-up switching element and the field switching element,
The controller is
A voltage sensor for detecting a voltage output between the first and second power supply lines from the converter;
A current sensor for detecting the field current flowing through the field winding;
A target value at a first sample point determined by a predetermined sample period for the boost current output from the converter to the first power supply line is set to a second sample point before the first sample point. Is set in accordance with the deviation between the voltage command value at the second sampling point and the voltage detected by the voltage sensor at the second sample point, and is supplied to the field winding in a direction to strengthen the field. The target value at the first sample point is set according to the deviation between the current command value at the second sample point and the detected current of the current sensor at the second sample point. Setting means;
By adding the target value of the boost current at the first sample point and the target value of the field magnetizing current at the first sample point, a current command value at the first sample point is obtained. Current command generating means for generating;
Switching control for switching the field switching element and the step-up switching element so that the detected current of the current sensor at the first sample point matches the current command value at the first sample point. Means for driving the motor. The switching control means includes
Using the current command value at the first sample point, the voltage across the terminals of the step-up switching element at the third sample point located between the first sample point and the second sample point A terminal-to-terminal voltage command value generating means for generating a command value;
Based on the generated the inter-terminal voltage command value of the third sample point, the third of the field magnetizing switching elements and duty ratio calculation means for calculating a duty ratio of the boosting switching element at the sample point When,
The control signal generating means for generating a switching control signal for switching the step-up switching element and the field switching element according to the calculated duty ratio at the third sampling point. Electric motor drive device. The duty ratio calculating means includes
A ratio of the current command value and the boost current at the third sampling point is calculated using the power balance in the steady state of the converter, and the boost switching element and field switching are calculated based on the calculated ratio A period in which the element is turned off is calculated, and a period in which only the step-up switching element is turned on based on the calculated period and the inter-terminal voltage command value at the third sampling point and the field The electric motor drive device according to claim 2, wherein a period during which the switching element is turned off is calculated. A method for controlling an electric motor drive device including a field winding and having a field pole formed by passing a field current through the field winding,
The motor driving device is
Power supply,
A converter for converting a DC voltage from the power source to output between the first and second power source lines;
An inverter that receives a voltage between the first and second power supply lines and converts the electric power to drive and control the motor;
A field switching element connected in parallel to the field winding;
A voltage sensor for detecting a voltage output between the first and second power supply lines from the converter;
A current sensor for detecting the field current flowing through the field winding,
The converter includes a step-up switching element electrically connected between the field winding and the second power supply line,
The field winding is electrically connected on a current path between the power supply and the first power supply line, and is configured such that a voltage switched by the boosting switching element is applied to both ends.
The control method is:
A target value at a first sample point determined by a predetermined sample period for the boost current output from the converter to the first power supply line is set to a second sample point before the first sample point. Is set in accordance with the deviation between the voltage command value at the second sampling point and the voltage detected by the voltage sensor at the second sample point, and is supplied to the field winding in a direction to strengthen the field. Setting a target value at the first sample point with respect to a difference between a current command value at the second sample point and a detected current of the current sensor at the second sample point ; ,
By adding the target value of the boost current at the first sample point and the target value of the field magnetizing current at the first sample point, a current command value at the first sample point is obtained. Generating step;
Switching control of the field switching element and the step-up switching element such that a detected current of the current sensor at the first sample point matches a current command value at the first sample point ; A method for controlling an electric motor driving device. The switching control step includes:
Using the current command value at the first sample point, the voltage across the terminals of the step-up switching element at the third sample point located between the first sample point and the second sample point Generating a command value;
A step of based on the generated inter-terminal voltage command value of the third sample point, computing the field magnetizing the duty ratio of the switching element and the step-up switching element in the third sample point,
And generating a switching control signal for switching the step-up switching element and the field switching element according to the calculated duty ratio at the third sampling point. Control method of the device. The step of calculating the duty ratio includes:
A ratio of the current command value and the boost current at the third sampling point is calculated using the power balance in the steady state of the converter, and the boost switching element and field switching are calculated based on the calculated ratio A period in which the element is turned off is calculated, and a period in which only the step-up switching element is turned on based on the calculated period and the inter-terminal voltage command value at the third sampling point and the field The method for controlling an electric motor drive device according to claim 5, wherein a period during which the switching element is turned off is calculated.

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