JP2020202713A - Motor control device - Google Patents

Abstract

To provide a motor control device that can be applied regardless of a modulation method and that performs dead time compensation with a simple circuit configuration.SOLUTION: A dead time term calculation unit 37 sets dead time terms VdDT and VqDT to compensate for an undervoltage with respect to a command voltage caused by a dead time T dead of an inverter 60 on the basis of dq axis current command values Id* and Iq*, a system voltage Vsys, and the number of switching times Nsw. Adders 38 and 39 output dq axis voltage command values Vd* and Vq* to which a feedback term, a feedforward term, and a dead time term are added. A modulator 40 generates a drive signal on the basis of the dq axis voltage command values Vd* and Vq*, the system voltage Vsys, the number of switching times Nsw, and an electric angle θe of a motor 80. The dead time term calculation unit 37 calculates the amplitude VampDT of the dead time term on the dq coordinates by the equation "VampDT=Vsys×T dead×Nsw×α (amplitude coefficient)".SELECTED DRAWING: Figure 2

Description

The present invention relates to a motor control device.

Conventionally, in a motor control device that drives a motor by the electric power supplied by a voltage inverter, a dead time compensation technique for compensating for an error voltage between a command voltage and an output voltage due to a dead time is known.

For example, in the dead time compensation method of the voltage type PWM inverter disclosed in Patent Document 1, the polarity of the compensation voltage is switched as each phase current passes through the zero cross point for the three-phase current output by the voltage type PWM inverter. .. Then, the compensation voltage is set to a value proportional to the amplitude of the phase current in the range where the amplitude of the phase current is from zero to a predetermined value, and the compensation voltage is set to a constant value in the range where the amplitude of the phase current exceeds the predetermined value. The compensation voltage generated for each phase is added to the PWM voltage command of each phase. It is stated that this can reduce the ripple of the phase current near the zero crossing point.

JP-A-2002-95262

In the technique of Patent Document 1, since a compensation voltage is generated for each phase and added to the PWM voltage command of each phase, a compensation voltage generator for three phases, an amplitude coefficient multiplier, and a compensation voltage addition calculator are required. Yes, the circuit becomes complicated. Further, as the method of the modulator that generates the output voltage of the inverter, only the sine wave PWM by carrier comparison is considered, and it cannot be applied to the overmodulation region where the amplitude of the modulated wave becomes large with respect to the carrier.

The present invention has been created in view of the above points, and an object of the present invention is to provide a motor control device that can be applied regardless of a modulation method and that performs dead time compensation with a simple circuit configuration. is there.

The motor control device according to the present invention includes an inverter (60), a current command value calculation unit (31), a feedback controller (34), a feedforward term calculation unit (35), and a dead time term calculation unit (37). And an adder (38, 39) and a modulator (40). The inverter is configured by bridging the switching elements (61-66) of the multi-phase upper and lower arms, converts DC power, and outputs multi-phase AC power to the motor (80).

The current command value calculation unit calculates the dq-axis current command value (Id ^* , Iq ^* ) based on the torque command required for the motor. The feedback controller has feedback terms (Vd_fb, Vq_fb) so that the detected value of the phase current energized from the inverter to the motor is coordinate-transformed so that the dq-axis current detection value (Id, Iq) follows the dq-axis current command value. Is calculated. The feedforward term calculation unit calculates the feedforward term (Vd_ff, Vq_ff) by a voltage equation based on the dq-axis current command value.

The dead time term calculation unit inputs the dead time term (Vd _DT , Vq _DT ) for compensating for the insufficient voltage with respect to the command voltage caused by the dead time of the inverter into the dq axis current command value or the dq axis current detection value and the inverter. The calculation is performed based on the system voltage (Vsys), which is the DC voltage, and the switching number (Nsw), which is the number of times the switching element switches per unit time.

The adder outputs a dq-axis voltage command value (Vd ^* , Vq ^* ) to which the feedback term, feedforward term, and dead time term are added. The modulator generates an inverter drive signal based on the dq-axis voltage command value, the system voltage, the number of switchings, and the electric angle (θe) of the motor.

The amplitude of the dead time term is represented by Vamp _DT , the system voltage is represented by Vsys, the dead time is represented by Tdead, the number of switchings is represented by Nsw, and the amplitude coefficient is represented by α. The amplitude coefficient is 0 when the current amplitude of the dq-axis current command value or the dq-axis current detection value is 0, the current amplitude gradually increases in the range from 0 to a predetermined value (x), and the current amplitude is equal to or higher than the predetermined value. It is set to be a positive constant value in the range. The dead time term calculation unit has the following formula: Vamp _DT = Vsys × Tdead × Nsw × α
Calculates the amplitude of the dead time term on the dq coordinates.

In the present invention, since the dead time term for compensating for the insufficient voltage with respect to the command voltage due to the dead time is calculated on the dq coordinates, the compensation circuit for three phases as in the prior art of Patent Document 1 becomes unnecessary. .. Since the coordinate conversion function of vector control, which is generally provided in three-phase motor control, can be used, the circuit configuration for dead time compensation is simplified.

Further, in the present invention, the modulation factor can be calculated from the final dq-axis voltage command value, and an output voltage waveform corresponding to the modulation factor can be easily generated. Therefore, it can be widely applied not only to sine wave PWM but also to a modulation method such as a waveform selection method in an overmodulation region where output waveform cannot be generated by carrier comparison. Further, since the amplitude of the dead time term is calculated by multiplying the amplitude coefficient which becomes 0 when the current amplitude is 0, a sudden change due to a change in voltage polarity due to the dead time is avoided.

The overall system block diagram to which the motor control device of each embodiment is applied. The control block diagram of the motor control device according to 1st Embodiment. Block diagram of (a) carrier comparison modulator and (b) waveform selection modulator. The figure which shows the relationship between a phase current and a voltage by a dead time. FIG. 4 is an enlarged view of (a) a Va portion (in the positive current direction) and (b) an enlarged view of the Vb portion (in the negative current direction). The figure explaining that the voltage by a dead time can be expressed on dq coordinates. The current and voltage vector diagrams at the time of (a) power running and (b) regeneration on the dq coordinates. The figure explaining the amplitude coefficient of the dead time term. The control block diagram of the motor control device according to 2nd Embodiment.

Hereinafter, a plurality of embodiments of the motor control device of the present invention will be described with reference to the drawings. The motor control device of each embodiment is a device mounted on, for example, a hybrid vehicle or an electric vehicle, and controls the drive of the main motor by the electric power supplied by the voltage inverter. Substantially the same configurations in a plurality of embodiments are designated by the same reference numerals and description thereof will be omitted. Further, the first and second embodiments are collectively referred to as "the present embodiment".

The overall system configuration to which the motor control device of each embodiment is applied will be described with reference to FIG. In this system, the motor control device 20 converts the DC power of the battery 10 into three-phase AC power by the inverter 60 and outputs it to the motor 80. The motor 80 is a permanent magnet type synchronous three-phase AC motor. The motor 80 of the present embodiment has both a function as an electric motor for generating torque for driving the drive wheels of a hybrid vehicle and a function as a generator for recovering energy by generating torque from the torque transmitted from the engine and the drive wheels.

The current sensor 70 detects the phase current applied to the motor 80 from the inverter 60 via the two-phase or three-phase power path among the three-phase power paths 81, 82, and 83, and outputs the phase current to the calculation unit 30. .. In the example of FIG. 1, two-phase currents of V-phase and W-phase are detected, and the remaining one-phase U-phase current is calculated by Kirchhoff's law. The rotation angle sensor 85 is a rotation angle sensor such as a resolver, and detects the mechanical angle θm of the motor 80.

In the inverter 60, six switching elements 61-66 of the upper and lower arms are bridge-connected. Specifically, the switching elements 61, 62, and 63 are U-phase, V-phase, and W-phase upper arm switching elements, respectively, and the switching elements 64, 65, and 66 are under the U-phase, V-phase, and W-phase, respectively. It is a switching element of the arm. The switching element 61-66 is composed of, for example, an IGBT, and a freewheeling diode that allows a current from the low potential side to the high potential side is connected in parallel.

The smoothing capacitor 15 is provided at the input portion of the inverter 60, and smoothes the "system voltage Vsys" which is a DC voltage input from the battery 10 to the inverter 60. The voltage sensor 16 detects the system voltage Vsys and outputs it to the calculation unit 30. The inverter 60 converts the DC power of the battery 10 into three-phase AC power by operating the switching elements 61-66 according to the drive signal commanded by the calculation unit 30, and converts the three-phase voltages Vu, Vv, and Vw into the motor 80. Apply to.

The arithmetic unit 30 of the motor control device 20 is composed of a microcomputer or the like, and includes a CPU, a ROM, a RAM, and a bus line connecting these configurations, which are not shown. The microcomputer controls software processing by executing a program stored in advance in a physical memory device such as a ROM (that is, a readable non-temporary tangible recording medium) with a CPU, or hardware processing by a dedicated electronic circuit. Execute. The calculation unit 30 inputs information on the torque command trq ^* required for the motor 80, the system voltage Vsys, the phase currents Iv, Iw, and the mechanical angle θm. The calculation unit 30 generates a drive signal for driving the inverter 60 based on the information.

By the way, in a voltage type inverter, in order to prevent the switching elements of the upper and lower arms of the same phase from turning on and short-circuiting at the same time, a dead time is set in which the switching elements of the upper and lower arms of the same phase are turned off at the same time. Conventionally, a dead time compensation technique for compensating for an error voltage between a command voltage and an output voltage due to a dead time in motor control has been known. Against this background, the motor control device 20 of the present embodiment performs dead time compensation on the dq coordinates. Subsequently, the configuration of the calculation unit 30 for implementing the dead time compensation will be described in detail for each embodiment. In the following first and second embodiments, the reference numerals of the "motor control device" and the "calculation unit" are assigned to the third digit following "20" and "30", respectively.

(First Embodiment)
The motor control device of the first embodiment will be described with reference to FIGS. 2 to 8. In the motor control device 201 shown in FIG. 2, the portion excluding the inverter (“INV” in the figure) 60 constitutes the calculation unit 301. The calculation unit 301 includes a current command value calculation unit 31, a three-phase-dq conversion unit 32, a current deviation calculation unit 33, a feedback controller 34, a feedforward term calculation unit 35, a switching count calculation unit 36, and a dead time term calculation unit 37. , Primary adder 38, secondary adder 39, modulator 40, electric angle calculation unit 86, electric angle speed calculation unit 87, and the like.

The electric angle calculation unit 86 converts the mechanical angle θm of the motor 80 detected by the rotation angle sensor 85 into the electric angle θe. The electric angular velocity calculation unit 87 calculates the electric angular velocity ω [rad / sec] by time-differentiating the electric angle θe. The electric angular velocity ω is also converted into the electric angular frequency f [Hz] (= ω / 2π).

The current command value calculation unit 31 calculates the dq-axis current command values Id ^* and Iq ^* based on the torque command trq ^* required for the motor 80 input from the upper vehicle control circuit. The three-phase-dq conversion unit 32 coordinates the three-phase currents Iu, Iv, and Iw using the electric angle θe, and calculates the dq-axis current detection values (also referred to as “actual current” as appropriate) Id and Iq. The current deviation calculation unit 33 calculates the deviations ΔId and ΔIq between the dq-axis current command values Id ^* and Iq ^* and the dq-axis current detection values Id and Iq.

The feedback controller 34 calculates the feedback terms Vd_fb and Vq_fb of the dq-axis voltage command value by, for example, PI calculation so that the dq-axis current detection values Id and Iq follow the dq-axis current command values Id ^* and Iq ^*. .. The feedforward term calculation unit 35 calculates the feedforward terms Vd_ff and Vq_ff of the dq axis voltage command value by the voltage equation based on the dq axis current command values Id ^* and Iq ^* .

In this case, the voltage equations are phase resistance R [Ω], d-axis inductance Ld [H], q-axis inductance Ld [H], electrical angular velocity ω [rad / sec], induced voltage constant φ [V · sec / rad]. It is expressed by the following equations (1.1) and (1.2) using.
Vd_ff = R × Id ^* −ω × Lq × Iq ^*・ ・ ・ (1.1)
Vq_ff = R × Iq ^* ＋ ω × Ld × Id ^* ＋ ωφ ・ ・ ・ (1.2)

The switching number calculation unit 36 calculates the switching number Nsw, which is the number of times the switching elements 61-66 of the inverter 60 switch per unit time, based on the electric angular frequency f and the like. The dead time term calculation unit 37 acquires current information, switching count Nsw, and system voltage Vsys information. In particular, the dead time term calculation unit 37 of the first embodiment acquires dq-axis current command values Id ^* and Iq ^* as current information. The dead time term calculation unit 37 calculates the dead time terms Vd _DT and Vq _DT based on this information. The dead time terms Vd _DT and Vq _DT are quantities that compensate for the undervoltage with respect to the command voltage caused by the dead time of the inverter 60, and the details will be described later.

The primary adder 38 adds the feedforward terms Vd_ff and Vq_ff and the dead time terms Vd _DT and Vq _DT . The secondary adder 39 adds the added values of the feedforward terms Vd_ff and Vq_ff to the dead time terms Vd _DT and Vq _DT to the feedback terms Vd_fb and Vq_fb, and outputs the dq axis voltage command values Vd ^* and Vq ^* . The modulator 40 generates a drive signal for the inverter 60 based on the dq-axis voltage command values Vd ^* , Vq ^* , the system voltage Vsys, the number of switching times Nsw, and the electric angle θe of the motor 80.

FIGS. 3A and 3B show two specific configurations of the modulator 40. The modulator 40a shown in FIG. 3A is a sine wave PWM type modulator based on carrier comparison, and has a dq-three-phase conversion unit 41 and a carrier comparison unit 42. The dq-three-phase conversion unit 41 converts the dq-axis voltage command values Vd ^* and Vq ^* into the three-phase voltage command values Vu ^* , Vv ^* and Vw ^* using the electric angle θe. The carrier comparison unit 42 generates a drive signal by comparing the duty ratio converted from the three-phase voltage command values Vu ^* , Vv ^* , and Vw ^* with the carrier based on the number of switching times Nsw and the system voltage Vsys.

The modulator 40b shown in FIG. 3B is a waveform selection type modulator, and has a modulation rate calculation unit 43, a waveform selection unit 44, and a drive signal generation unit 45. The modulation factor calculation unit 43 calculates the modulation factor m from the ratio of the amplitudes of the dq-axis voltage command values Vd ^* and Vq ^* to the system voltage Vsys. The waveform selection unit 44 selects and outputs one of a plurality of voltage waveforms (so-called “pulse patterns”) stored in advance based on the modulation factor m and the number of switching times Nsw. The drive signal generation unit 45 uses the selected voltage waveform to generate a drive signal based on the relationship between the phase of the dq-axis voltage command values Vd ^* and Vq ^* and the electric angle θe. The waveform selection type modulator 40b can generate a drive signal even in an overmodulation region where the modulation factor m is equal to or greater than a predetermined value.

Next, the voltage generated by the dead time will be described with reference to FIGS. 1, 4, and 5. In FIG. 1, attention is paid to the phase current flowing through the U phase of the inverter 60. Here, the current direction from the inverter 60 to the motor 80 is defined as the positive direction. During the dead time, a current flows from the low potential side to the high potential side through the freewheeling diodes of the switching elements 61 and 64.

That is, during the dead time in the positive direction of the current, a current flows through the freewheeling diode of the upper arm switching element 61 as shown by the thick solid arrow. During the dead time in the negative current direction, a current flows through the freewheeling diode of the lower arm switching element 64 as shown by the thick dashed arrow. Therefore, a voltage opposite to the phase current is generated due to the dead time.

FIG. 4 shows the time change between the phase current and the voltage due to the dead time. FIGS. 5A and 5B show the relationship between the PWM pulse and the phase voltage in the positive and negative directions of the current, respectively. The dead time Tdead is provided for each carrier cycle Tc along with the rising edge and the falling edge of the PWM pulse, and the difference obtained by subtracting the PWM pulse from the phase voltage is generated as the “voltage due to the dead time”.

The voltage due to the dead time is generated for each carrier cycle and has a phase shifted by 180 [deg] with respect to the phase of the phase current. Further, in the region where the phase currents have the same sign, that is, the region where the zero cross point does not cross, the voltage per unit time is constant, and the amplitude is constant regardless of the electric cycle (or frequency).

When the phase current is other than 0, the voltage amplitude Vdead [Vrms] due to the dead time is calculated by the equation (2) based on the system voltage Vsys, the dead time Tdead [sec], and the carrier period Tc [sec]. (1 / √2) in the equation (2) is a conversion coefficient from the DC voltage peak value [Vdc] to the amplitude effective value [Vrms] on the premise of a sine wave.
Vdead = Vsys × (Tdead / Tc) × (1 / √2) ・ ・ ・ (2)

When the phase current is 0, the output voltage does not change because no current flows through the freewheeling diode of the switching elements 61-66. Therefore, no voltage is generated due to the dead time.

Subsequently, with reference to FIGS. 6 and 7, the calculation of the dead time term on the dq coordinates will be described. As shown in FIG. 6, the “voltage due to dead time” can be regarded as a sine wave having a certain voltage amplitude with the voltage phase shifted by 180 [deg] with respect to the phase of the phase current. Therefore, the "voltage due to dead time" can be expressed on the dq coordinates.

Figures 7 (a) and 7 (b) show the current and voltage vectors during power running and regeneration, respectively. In the first embodiment, a current command vector is used as the current vector. Assuming that the phase of the current command vector with respect to the d-axis in the positive direction is θi, the phase of the “voltage due to dead time” is expressed as “θi + 180 [deg]”. Hereinafter, the current phase and the voltage phase shall mean the phase with reference to the d-axis in the positive direction.

This "voltage due to dead time" corresponds to the undervoltage which is the difference between the final voltage command and the feedforward voltage command (theoretical value). In other words, the final voltage command is obtained by adding the voltage that cancels the "voltage due to the dead time" to the feedforward voltage command (theoretical value) as the dead time term. That is, since the voltage phase of the dead time term is the same as the phase θi of the current command, the dead time terms Vd _DT and Vq _DT can be calculated based on this theory to perform dead time compensation.

According to the equation (3), the dead time term calculation unit 37 of the first embodiment has a dead time term Vd from the ratio of the d-axis component Id ^* and the q-axis component Iq ^* of the dq-axis current command value to the current amplitude I ^* amp. Calculate _{DT and} Vq _DT .
Vd _DT = Vamp _DT x cos (θi) = Vamp _DT x Id ^* / I ^* amp
Vq _DT = Vamp _DT x sin (θi) = Vamp _DT x Iq ^* / I ^* amp
... (3)

Here, the amplitude Vamp _DT of the dead time term is calculated by the equation (4) based on the system voltage Vsys, the dead time Tdead [sec], the number of switching times Nsw [times / sec], and the amplitude coefficient α. The software setting value is used for the dead time Tdead.
Vamp _DT = Vsys x Tdead x Nsw x α ... (4)

The equation (2) of the above-mentioned "voltage amplitude Vdead due to dead time" is a theoretical equation, whereas the equation (4) is an arithmetic expression for calculating the amplitude Vamp _DT of the dead time term from the viewpoint of control calculation. It is characterized in that the amplitude coefficient α is multiplied. The significance of the amplitude coefficient α will be described with reference to FIG.

As shown in FIG. 4, when “current ≈ 0” near the zero crossing point of the phase current, no voltage due to dead time is generated. Therefore, by setting the amplitude coefficient α to 0 when the amplitude I ^* amp of the dq-axis current command value becomes 0, it is possible to avoid a sudden change in the amplitude Vamp _DT of the dead time term due to the change in voltage polarity due to the dead time. it can.

Specifically, the amplitude coefficient α is a positive constant value αmax in the range where the current amplitude I ^* amp is a predetermined value x or more. Further, in the range where the current amplitude I ^* amp is from 0 to a predetermined value x, the amplitude coefficient α gradually increases in proportion to the current amplitude I ^* amp. Here, the predetermined value x is set according to, for example, the capacitance of the switching element.

The constant value αmax corresponds to the conversion coefficient from the DC voltage peak value [Vdc] to the dq axis voltage [Vdq] (√3 / √2). This value is a combination of the conversion from the DC voltage peak value [Vdc] to the AC voltage amplitude [Vrms] and the conversion from the phase voltage effective value [Vrms] to the dq axis voltage [Vdq].

(effect)
The effect of the motor control device 201 of the first embodiment will be described. First, the case where the dead time term is not added to the feed forward voltage command at all, or the case where the dead time term added to the feed forward voltage command is not calculated correctly is compared.

As shown in FIGS. 7 (a) and 7 (b), the phase of the voltage due to the dead time changes significantly between the time of power running and the time of regeneration. If the voltage due to the dead time is not considered at all, or if the dead time term is not calculated correctly, the voltage command cannot follow the torque command that straddles power running and regeneration, resulting in deterioration of drivability. On the other hand, in the first embodiment, since the phase of the dead time term is correctly calculated based on the dq axis current command values Id ^* and Iq ^* , the voltage command can follow the torque command straddling power running and regeneration, and the driver. The ability is improved.

Next, it is compared with the prior art of Patent Document 1 (Japanese Unexamined Patent Publication No. 2002-95262). In the prior art, a compensation voltage is generated for each phase and added to the PWM voltage command of each phase, so that a compensation circuit for three phases is required, whereas in this embodiment, dead time compensation is performed on the dq coordinates. Therefore, the compensation circuit for three phases becomes unnecessary. Since the coordinate conversion function of vector control, which is generally provided in three-phase motor control, can be used, the circuit configuration for dead time compensation is simplified.

Further, in the prior art of Patent Document 1, the amplitude of the dead time compensation voltage is fed back, but since the voltage phase and the modulation factor are not considered, a modulation method other than the sinusoidal PWM by carrier comparison, for example, in an overmodulation region It is difficult to apply to the modulation method of. In the present embodiment, the modulation factor can be calculated from the final dq-axis voltage command values Vd ^* and Vq ^*, and an output voltage waveform corresponding to the modulation factor can be easily generated. Therefore, it can be widely applied not only to sine wave PWM but also to a modulation method such as a waveform selection method in an overmodulation region where output waveform cannot be generated by carrier comparison.

Further, since the amplitude Vamp _DT of the dead time term is calculated by multiplying the amplitude coefficient α which becomes 0 when the current amplitude is 0, a sudden change due to a change in voltage polarity due to the dead time is avoided.

In particular, the dead time term calculation unit 37 of the first embodiment calculates the dead time terms Vd _DT and Vq _DT using the dq-axis current command values Id ^* and Iq ^* . Since the calculation is performed in the command calculation cycle, the calculation load can be reduced as compared with the case where the calculation is performed in a high-speed calculation cycle such as a carrier task. Further, since the dq-axis current command values Id ^* and Iq ^* based on the torque command trq ^* are used immediately, the torque response is faster than when the dq-axis current detection values (actual current) Id and Iq are used.

(Second Embodiment)
The motor control device 202 of the second embodiment will be described with reference to FIG. In the motor control device 202 of the second embodiment, the components of the calculation unit 302 are the same as those of the calculation unit 301 of the first embodiment, and only the current information input to the dead time term calculation unit 37 is different. In the second embodiment, instead of the dq-axis current command values Id ^* and Iq ^* , the dq-axis current detection values Id and Iq, that is, the actual current energized from the inverter 60 to the motor 80 are input to the dead time term calculation unit 37. To. The current amplitude of the dq-axis current detection value is expressed as Imp without " ^* ".

The "current command vector" in the dq coordinates of FIG. 7 is replaced with the "real current vector" and is interpreted in the same manner. That is, the dead time term having the same phase as the phase θi of the actual current vector is added to the feed forward voltage command to calculate the voltage command. Further, the current amplitude "I ^* amp" on the horizontal axis in FIG. 8 is replaced with "Iamp".

The dead time term calculation unit 37 of the second embodiment calculates the amplitude Vamp _DT of the dead time term by the equation (4) as in the first embodiment. Further, the dead time term calculation unit 37 calculates the dead time terms Vd _{DT and} Vq _DT from the ratio of the d-axis component Id and the q-axis component Iq of the dq-axis current detection value to the current amplitude Iamp according to the equation (5). ..

Vd _DT = Vamp _DT x cos (θi) = Vamp _DT x Id / Iamp
Vq _DT = Vamp _DT x sin (θi) = Vamp _DT x Iq / Iamp
... (5)

The second embodiment is inferior in the speed of torque response to the first embodiment using the current command values Id ^* and Iq ^* , but since the actual currents Id and Iq are used, the instantaneous dead time terms Vd _DT and Vq _DT are set. It can be calculated correctly. Therefore, it is possible to prevent deterioration of drivability even when the voltage suddenly changes due to dead time.

(Other embodiments)
(A) amplitude coefficient α, as shown in FIG. 8, not always proportional to the current amplitude I ^* # 038 (or Iamp) current amplitude I ^* # 038 between 0 and a predetermined value x (or Iamp), It may be gradually increased in a curved shape or a polygonal line between 0 and a predetermined value x.

(B) The motor control device of the present invention is applicable not only to the main motor of a hybrid vehicle or an electric vehicle, but also to any motor to which power is supplied by a voltage inverter. Further, the number of phases of the multi-phase AC motor is not limited to three phases and may be any number of phases.

As described above, the present invention is not limited to the above-described embodiment, and can be implemented in various embodiments without departing from the spirit of the present invention.

201, 202 ... Motor control device,
31 ... Current command value calculation unit,
34 ... Feedback controller,
35 ... Feedforward term calculation unit,
37 ... Dead time term calculation unit,
38, 39 ... adder,
40 ... Modulator,
60 ... Inverter, 61-66 ... Switching element,
80 ... Motor.

Claims (4)

A multi-phase upper and lower arm switching element (61-66) is bridge-connected to form an inverter (60) that converts DC power and outputs multi-phase AC power to a motor (80).
A current command value calculation unit (31) that calculates dq-axis current command values (Id ^* , Iq ^* ) based on the torque command required for the motor, and
Feedback terms (Vd_fb, Vq_fb) are set so that the dq-axis current detection values (Id, Iq) obtained by coordinate-transforming the detection values of the phase current energized from the inverter to the motor follow the dq-axis current command value. The feedback controller (34) that calculates and
A feedforward term calculation unit (35) that calculates a feedforward term (Vd_ff, Vq_ff) by a voltage equation based on the dq-axis current command value, and
The dead time term (Vd _DT , Vq _DT ) for compensating for the insufficient voltage with respect to the command voltage caused by the dead time of the inverter is set to the dq axis current command value, the dq axis current detection value, or the DC voltage input to the inverter. A dead time term calculation unit (37) that calculates based on the system voltage (Vsys), which is the number of times the switching element switches, and the number of times the switching element switches (Nsw) per unit time.
Adders (38, 39) that output dq-axis voltage command values (Vd ^* , Vq ^* ) obtained by adding the feedback term, the feedforward term, and the dead time term.
A modulator (40) that generates a drive signal of the inverter based on the dq-axis voltage command value, the system voltage, the number of switchings, and the electric angle (θe) of the motor.
With
When the amplitude of the dead time term is expressed as Vamp _DT , the system voltage is expressed as Vsys, the dead time is expressed as Tdead, the number of switching times is expressed as Nsw, and the amplitude coefficient is expressed as α.
The amplitude coefficient is 0 when the current amplitude of the dq-axis current command value or the dq-axis current detection value is 0, and the current amplitude gradually increases in the range of 0 to a predetermined value (x), and the current amplitude Is set to be a positive constant value within the range of the predetermined value or more.
The dead time term calculation unit has the following formula: Vamp _DT = Vsys × Tdead × Nsw × α
A motor control device that calculates the amplitude of the dead time term on the dq coordinates. The d-axis component of the dead time term is represented by Vd _DT , and the q-axis component is represented by Vq _DT .
When the d-axis component of the dq-axis current command value is expressed as Id ^* , the q-axis component is expressed as Iq ^* , the current amplitude is expressed as I ^* amp, and the current phase based on the positive d-axis is expressed as θi.
Based on the dq-axis current command value, the dead time term calculation unit has the following formula Vd _DT = Vamp _DT × cos (θi) = Vamp _DT × Id ^* / I ^* amp.
Vq _DT = Vamp _DT x sin (θi) = Vamp _DT x Iq ^* / I ^* amp
The motor control device according to claim 1, wherein the dead time term is calculated accordingly. The d-axis component of the dead time term is represented by Vd _DT , and the q-axis component is represented by Vq _DT .
When the d-axis component of the dq-axis current detection value is expressed as Id, the q-axis component is expressed as Iq, the current amplitude is expressed as Imp, and the current phase based on the d-axis in the positive direction is expressed as θi.
Based on the dq-axis current detection value, the dead time term calculation unit has the following formula Vd _DT = Vamp _DT × cos (θi) = Vamp _DT × Id / Iamp.
Vq _DT = Vamp _DT x sin (θi) = Vamp _DT x Iq / Iamp
The motor control device according to claim 1, wherein the dead time term is calculated accordingly. The modulator (40b) has a plurality of voltage waveforms stored in advance based on the modulation factor (m) calculated from the ratio of the amplitude of the dq-axis voltage command value and the system voltage and the number of switchings. The motor control device according to claim 2 or 3, wherein one of the voltage waveforms is selected and output from the above.

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