JP2014166054A - Motor controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor controller having improved torque responsiveness.SOLUTION: Provided is a motor controller for controlling an inverter 2 equipped with a switching element and a motor 3 connected to the inverter 2, the motor controller comprising: current command value calculation means for calculating a basic current command value on the basis of a torque command value inputted from the outside and the rotation speed of the motor 3; compensation means for compensating for a delay in rotor magnetic flux response of the motor 3 by amplifying the basic current command value; extended current command value limiting means for limiting the current command value calculated by the compensation means with an extended current limiting value; and control means for controlling on/off of the switching element on the basis of the command value limited by the extended current command value limiting means, the extended current limiting value being set on the basis of a thermal time constant of the switching element and being a current value higher than a rated current of the switching element.

Description

  The present invention relates to a motor control device.

  In an induction motor control device having an excitation current command value calculation unit for calculating an excitation current command value for generating a target magnetic flux and an excitation current limiter unit for limiting positive and negative upper limit values of the excitation current command value, an excitation current command The value calculation unit calculates the excitation current command value so that the value of the excitation current is greatly changed in order to change the response of the secondary magnetic flux, and the excitation current limiter unit is excessively large to protect the drive circuit of the inverter. A device that sets the upper limit value so that no current flows is disclosed (Patent Document 1).

JP-A-8-163900

  However, in the motor control device described above, in order to increase the response of the magnetic flux, when a large excitation current is passed transiently, the excitation current is limited by the steady maximum allowable current that is the upper limit value. There is a problem that the convergence time until the actual current value reaches the command value becomes longer, and the torque response becomes worse.

  The problem to be solved by the present invention is to provide a motor control device with improved torque response.

  The present invention amplifies the basic current command value to compensate for the delay in the rotor magnetic flux response of the motor, limits the compensated current command value with the expanded current limit value, and limits the command value with the expanded current limit value. Based on the above, the switching element is turned on and off, the expanded current limit value is set based on the thermal time constant of the switching element, and the current value is higher than the rated current of the switching element. Solve.

  In the present invention, since a current value higher than the rated current of the switching element can be made to flow transiently, the rise of the rotor magnetic flux becomes faster, and as a result, the response of torque can be improved.

1 is a block diagram of an electric vehicle system according to an embodiment of the present invention. It is a graph for demonstrating the map referred by the motor torque control part of FIG. 1, Comprising: It is a graph which shows the correlation of the motor rotation speed and torque command value which were set for every accelerator opening. It is a block diagram of the current control part of FIG. FIG. 4 is a block diagram of the current command value calculator of FIG. 3. FIG. 5 is a block diagram of an enlarged current limit value calculation unit in FIG. 4. FIG. 5 is a block diagram of a current command value limiting unit in FIG. 4. FIG. 5 is a block diagram of a current command value limiting unit in FIG. 4. It is a flowchart which shows the control procedure of the motor controller of FIG. It is a flowchart which shows the control procedure of step S4 of FIG. It is a flowchart which shows the control procedure of step S45 of FIG. It is a flowchart which shows the control procedure of step S46 of FIG. It is a graph which shows the response of the motor controlled by the motor control device concerning a comparative example. It is a graph which shows the response of the motor controlled by the motor control device concerning the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<< First Embodiment >>
FIG. 1 is a block diagram showing a configuration of an electric vehicle system equipped with a motor control device according to an embodiment of the present invention. Hereinafter, an example in which the motor control device of this example is applied to an electric vehicle will be described. However, the motor control device of this example can be applied to a vehicle other than an electric vehicle such as a hybrid vehicle (HEV).

  As shown in FIG. 1, the vehicle including the motor control device of this example is a battery 1, an inverter 2, a motor 3, a speed reducer 4, a drive shaft (drive shaft) 5, wheels 6, 7, a voltage sensor 8, and a current sensor. 9, a rotation sensor 10 and a motor controller 20 are provided.

  The battery 1 is a motive power source of the vehicle, and is configured by connecting a plurality of secondary batteries in series or in parallel. The inverter 2 has a power conversion circuit in which a plurality of switching elements such as IGBTs and MOSFETs are connected for each phase. Inverter 2 switches on and off of the switching element according to a drive signal from motor controller 20, thereby converting DC power output from battery 1 into AC power and outputting it to motor 3. The motor 3 is driven by flowing a desired current. The inverter 2 reversely converts the AC power output by the regeneration of the motor 3 and outputs it to the battery 1.

  The motor 3 is a driving source of the vehicle, and is an induction motor for transmitting driving force to the driving wheels 6 and 7 via the speed reducer 4 and the drive shaft 5. The motor 3 is rotated by the driving wheels 6 and 7 while the vehicle is running, and generates regenerative driving force to recover the kinetic energy of the vehicle as electric energy. Thereby, the battery 1 is discharged by the power running of the motor 3 and charged by the regeneration of the motor 3.

  The voltage sensor 8 is a sensor that detects the voltage of the battery 1, and is connected between the battery 1 and the inverter 2. The detection voltage of the voltage sensor 8 is output to the motor controller 20. The current sensor 9 is a sensor for detecting the current of the motor 3, and is connected between the inverter 2 and the motor 3. The current detected by the current sensor 9 is output to the motor controller 20. The rotation speed sensor 10 is a sensor for detecting the rotation speed of the motor 3, and is constituted by a resolver or the like. The detection value of the rotation speed sensor 10 is output to the motor controller 20.

The motor controller 20 is a PWM for operating the inverter 2 based on the vehicle speed (V) of the vehicle, the accelerator opening (APO), the rotor phase (θ _re ) of the motor 3, the motor current, the voltage of the battery 1, and the like. A signal is generated and output to a drive circuit (not shown) that operates the inverter 2. Then, the drive circuit controls the drive signal of the switching element of the inverter 2 based on the PWM control signal and outputs it to the inverter 2. Thereby, the motor controller 20 drives the motor 3 by operating the inverter 2.

  The motor controller 20 is a controller that controls the inverter 2 and the motor 3. The motor controller 20 has a motor torque control unit 21, a vibration suppression control unit 22, and a current control unit 23.

The motor torque control unit 21 is configured to output a torque requested by a user operation or a requested torque on the system from the motor 3 based on a vehicle information signal indicating a vehicle variable input to the motor controller 20. T _m1 ^* ) is calculated and output to the vibration suppression control unit 22.

  The motor torque control unit 21 stores in advance a torque map showing the relationship of FIG. FIG. 2 is a graph showing the correlation between the motor speed and the basic target torque command value set for each accelerator opening. The torque map is set in advance according to the relationship between the torque command value and the rotation speed of the motor 3 for each accelerator opening. The torque map is set as a torque command value for efficiently outputting torque from the motor 3 with respect to the accelerator opening and the motor speed.

The number of rotations (rotational speed) of the motor is calculated based on the detection value of the rotation sensor 10. The accelerator opening is detected by an accelerator opening sensor (not shown). Then, the motor torque control unit 21 calculates a basic target torque command value (T _m1 ^* ) corresponding to the input accelerator opening (APO) and the motor rotation speed with reference to the torque map, and the vibration suppression control unit 22 Output to. When the shift lever is set to the parking position and the neutral position, the basic target torque command value (T _m1 ^* ) becomes zero.

The basic target torque command value (T _m1 ^* ) is not limited to the accelerator opening and the motor rotation speed, and may be calculated by adding the vehicle speed, for example. The vehicle speed V [km / h] is acquired by communication from another controller such as a meter or a brake controller, or the tire mechanical radius (ωrm) is multiplied by the tire dynamic radius (R) and divided by the gear ratio of the final gear. Thus, the vehicle speed v [m / s] may be obtained and multiplied by the unit conversion coefficient (3600/1000) from [m / s] to [km / h].

The vibration suppression control unit 22 receives the basic motor torque command value T _m1 ^* and the motor rotation speed N _m and generates the torsional vibration of the drive shaft 5 (drive shaft) without sacrificing the response of the drive shaft torque. A post-damping control torque command value T _m2 ^* for suppressing vibration of the driving force transmission system is calculated. For detailed control of the vibration suppression control unit 22, refer to, for example, Japanese Patent Application Laid-Open Nos. 2001-45613 and 2003-9559. Then, the vibration suppression control unit 22 outputs the post-vibration control torque command value T _m2 ^* calculated based on the basic target torque command value (T _m1 ^* ) to the current control unit 23. Note that the vibration suppression control unit 22 is not always necessary.

The current control unit 23 is a control unit that controls the current flowing through the motor 3 based on the torque command value (T _m2 ^* ). Hereinafter, the configuration of the current control unit 23 will be described with reference to FIG. FIG. 3 is a block diagram of the current control unit 23, the battery 1, and the like.

  The current control unit 23 includes a current command value calculator 30, a subtractor 41, a current FB controller 42, a coordinate converter 43, a PWM converter 44, an AD converter 45, a coordinate converter 46, a pulse counter 47, an angular velocity calculator. 48, a slip angular velocity calculator 49, a power supply phase calculator 50, and a motor rotation number calculator 51.

The current command value calculator 30 includes a post-vibration control torque command value (T _m2 ^* ) input from the vibration suppression control unit 22, and the motor 3 rotation speed (N _m ) input from the motor rotation speed calculator 51. ) And the detection voltage (V _dc ) of the voltage sensor 8 are input, and the γδ axis current command values (I _γ ^* , I _δ ^* ) are calculated and output. Here, the γδ axes indicate components of the rotating coordinate system.

The subtractor 41 calculates a deviation between the γδ axis current command value (I _γ ^* , I _δ ^* ) and the γδ axis current (I _γ ^* , I _δ ^* ), and outputs the deviation to the current FB controller 42. The current FB controller 42 feeds back the γ-axis current (I _γ ) and the δ-axis current (I _δ ) to match the γ-axis current command value (I _γ ) and the δ-axis current command value (I _δ ^* ), respectively. It is a controller to control. The current FB controller 42 controls the γδ axis current (I _γ , I _δ ) to follow the γδ axis current command value (I _γ ^* , I _δ ^* ) with a predetermined response without a steady deviation. The calculation is performed, and the voltage command values (v _γ ^* , v _δ ^* ) of the γδ axis are output to the coordinate converter 43. The γ-axis current represents the excitation current of the motor 3, and the σ-axis current represents the torque current of the motor 3. Further, non-interference control may be added to the control of the subtractor 41 and the current FB controller 42.

The coordinate converter 43 receives the γδ axis voltage command value (v _γ ^* , v _δ ^* ) and the power supply phase (θ) calculated by the power supply phase calculator 50 as inputs, and receives the γδ axis voltage command value (v _γ ^* , v _δ ^* ) is converted into voltage command values (v _u ^* , v _v ^* , v _w ^* ) of the u, v, and w axes in the fixed coordinate system and output to the PWM controller 44.

PWM converter 44, the voltage command value input _{^{(V u *, V v *}} , V w *) based on the switching signal _^(D * ^uu switching elements of the inverter _{^{2, D * ul, D *}} vu, D ^* _Vl , D ^* _wu , D ^* _wl ) are generated and output to the inverter 7.

The A / D converter 45 samples a phase current (I _u , I _v ) that is a detection value of the current sensor 9 and outputs the sampled phase current (I _us , I _vs ) to the coordinate converter 46. Since the sum of the three-phase current values becomes zero, the w-phase current is not detected by the current sensor 9, and instead, the coordinate converter 46 converts the input phase current (I _us , I _vs ). Based on this, the phase current (I _ws ) of the w phase is calculated. The w-phase current may be detected by the current sensor 9 provided in the w-phase.

The coordinate converter 46 is a converter that performs three-phase to two-phase conversion, and uses the power phase (θ) to convert the phase current (I _us , I _vs , I _ws ) of the fixed coordinate system to the γδ axis of the rotating coordinate system. The current is converted into current (I _γs , I _δs ) and output to the subtractor 41. Thereby, the current value detected by the current sensor 9 is fed back.

The pulse counter 47 counts the pulses output from the rotation sensor 10 to obtain the rotor phase (θ _re ) (electrical angle) that is the position information of the rotor of the motor 3 and outputs it to the angular velocity calculator 48. To do.

The angular velocity calculator 48 calculates the rotor angular velocity (ω _re ) (electrical angle) by differentiating the rotor phase (θ _re ), and outputs it to the power supply phase calculator 50. The angular velocity calculator 48 divides the calculated rotor angular velocity (ω _re ) by the pole pair number p of the motor 3 to calculate the rotor mechanical angular velocity (ω _rm ) [rad / s] which is the mechanical angular velocity of the motor. And output to the motor rotation number calculator 51.

ただし、Ｍは相互インダクタンスを、τ_φはロータ磁束の応答時定数である。なお、τ_φはＬｒ／Ｒｒで表され、Ｌｒはロータの自己インダクタンスを、Ｒｒはロータ抵抗を示す。 The slip angular velocity calculator 49 calculates a rotor magnetic flux estimated value (φ _est ) in consideration of the rotor magnetic flux response delay with respect to the excitation current command value (I _γ ^* ) by the following equation (1).

Here, M is the mutual inductance, and τ _φ is the response time constant of the rotor magnetic flux. Note that τ _φ is expressed by Lr / Rr, where Lr is the rotor self-inductance and Rr is the rotor resistance.

なお、これらＭ、τ_φ、Ｍ・Ｒｒ／Ｌｒ等の値は、ロータ温度や電流値、トルク指令値に対して予め計算または実験により算出した値をテーブルに格納して使用してもよい。 In addition, the slip angular velocity calculator 49 has a ratio between the torque current command value (I _δ ^* ) and the estimated rotor magnetic flux value (φ _est ) obtained from the equation (1) as expressed by the equation (2). The slip angular velocity (ωse) is calculated by dividing a constant determined by the characteristics of the motor.

For these values of M, τ _φ , M · Rr / Lr, etc., values calculated in advance or experimentally for the rotor temperature, current value, and torque command value may be stored in a table.

Then, the slip angular velocity calculator 49 outputs the slip angular velocity (ω _se ) calculated as described above to the power supply phase calculator 50. Thus, by setting the slip angular velocity (ω _se ), the output torque can be handled by the product of the torque current and the rotor magnetic flux.

As shown in the following formula (3), the power phase calculator 50 integrates the rotor angular velocity (ω _re ) (electrical angle) while adding the slip angular velocity (ω _se ), thereby _obtaining the power phase. (Θ) is calculated and output to the coordinate converters 43 and 46.

The motor rotational speed calculator 51 multiplies the rotor mechanical angular velocity (ω _rm ) by a coefficient (60 / 2π) for unit conversion from [rad / s] to [rpm], so that the motor rotational speed ( Nm) is calculated and output to the current command value calculator 30.

  Next, the configuration of the current command value calculator 30 will be described with reference to FIG. FIG. 4 is a block diagram showing a configuration of the current command value calculator 30.

  The current command value calculator 30 includes a basic current command value calculation unit 31, a magnetic flux response compensation unit 32, an excitation current command value change amount calculation unit 33, an expanded current command value determination unit 34, an expanded current limit value calculation unit 35, and a current. A command value calculation unit 36 is provided.

The basic current command value calculation unit 31 includes a basic γδ-axis current command value (I _γ0 ^* ) for the post-damping control torque command value (T _m2 ^* ), the voltage (V _dc ) of the battery 1 and the motor speed (N _m ) ^. , I _δ0 ^* ) is recorded in advance. The basic γδ axis current command values (I _γ0 ^* , I _δ0 ^* ) are based on the torque command value after vibration suppression control (T _m2 ^* ), the voltage (V _dc ) of the battery 1 and the motor speed (N _m ). This is a current command value that optimizes the overall efficiency of the inverter 2 and the motor 3, and is a value set in advance through experiments or calculations. Then, the basic current command value calculation unit 31 refers to the map and corresponds to the post-vibration control torque command value (T _m2 ^* ), the voltage (V _dc ) of the battery 1, and the motor rotation speed (N _m ). Basic γδ-axis current command values (I _γ0 ^* , I _δ0 ^* ) are calculated and output to the magnetic flux response compensation unit 32, the excitation current command value change amount 33, and the expanded current limit value calculation unit 35.

The magnetic flux response compensator 32 calculates the magnetic flux compensation γ-axis current command value (I _γ1 ^* ) so as to amplify the basic current command value by advancing the phase of the delay in order to compensate for the rotor magnetic flux lag. .

  In general, the response of the rotor magnetic flux is slower by an order of magnitude or more than the response of the torque current. The output of the motor 3 is proportional to the product of the rotor magnetic flux and the stator torque current. Therefore, the torque response is delayed due to the response delay of the rotor magnetic flux. The magnetic flux response compensation unit 32 compensates the current command value so as to compensate for such a delay in torque response. As a result, since the basic current command value increases in the motor 3, a large excitation current can flow transiently, so that the torque response can be improved while improving the rotor magnetic flux response.

The magnetic flux response compensator 32 _adds the response time constant (τ _i ) of the stator current and the response time constant of the rotor magnetic flux (τ _i ) to the basic γ-axis current command value (I _γ0 ^* ) as shown in the following equation (4). By multiplying a function including τ _φ ), the magnetic flux compensation γ-axis current command value (I _γ1 ^* ) is calculated and output to the current command value limiter 36.

The relationship of τ _i <τ _φ is established between the response time constant (τ _i ) of the stator current and the response time constant (τ _φ ) of the rotor magnetic flux. Therefore, the magnetic flux response compensator 32 functions as a phase advance compensator by calculating the magnetic flux compensation γ-axis current command value (I _γ1 ^* ) using Equation (4).

ただし、τ_０は、基本γ軸電流指令値（Ｉ_γ０ ^＊）の変化を、どのぐらいの長さの時間で近似的に演算するかを示す設定値であって、設計または実験により予め設定されている。 The exciting current command value change amount calculation unit 33 uses the approximate expression shown in the following equation (5) to change the basic γ-axis current command value from the input basic γ-axis current command value (I _γ0 ^* ). The amount (dI _γ0 ^* ) is calculated and output to the enlarged current command value determination unit 34.

However, τ ₀ is a set value indicating how long the change in the basic γ-axis current command value (I _γ0 ^* ) is approximately calculated, and is set in advance by design or experiment. ing.

Incidentally, the amount of change _(dI γ0 ^_*) is the last basic γ-axis current command value at operation and (I _{[gamma] 0 ^*),} the difference between the current basic γ-axis current command value at operation (I _{[gamma] 0 ^*)} very Good. A calculation unit such as a current command value calculator 30 included in the motor controller 20 calculates a command value or the like at a predetermined control cycle. The command value of the previous calculation value indicates the command value calculated at a timing earlier than the command value of the current calculation value by a predetermined control period.

The enlarged current command value determination unit 34 compares the change amount (dI _γ0 ^* ) of the basic γ-axis current command value with the determination threshold value (I ₀ ), and based on the comparison result, an expanded current limit value calculation unit to be described later It is determined whether the expanded current limit value calculated in 35 is the limit value of the excitation current limit value or the limit value of the torque current limit value. The expanded current limit value is a current limit value when the current is transiently increased in order to increase the response of the rotor magnetic flux. The configuration of the expanded current limit value calculation unit 35 and the expanded current limit value will be described later (see FIG. 5).

When the change amount of the exciting current is large, the torque response can be enhanced by increasing the response of the rotor magnetic flux. Therefore, when the change amount (dI _γ0 ^* ) is larger than the determination threshold value (I ₀ ), the enlarged current command value determination unit 34 determines that the change amount of the excitation current is large, and sets the limit value of the excitation current command value. Then, a signal for enlarging to the enlarged current limit value is output to the current command value limiter 36.

On the other hand, when the change amount of the exciting current is small, the exciting current is already constant, and therefore, the limit value of the exciting current need not be increased to increase the response of the rotor magnetic flux. Therefore, when the change amount (dI _γ0 ^* ) and the determination threshold value (I ₀ ) or less, the enlarged current command value determination unit 34 determines that the change amount of the excitation current is small, and the limit value of the torque current limit value Is output to the current command value limiting unit 36.

The determination threshold (I ₀ ) is a threshold for determining whether the expanded current limit value is the limit value of the excitation current limit value or the limit value of the torque current limit value. Is a preset threshold value.

The expanded current limit value calculation unit 35 is a calculation unit that calculates an expanded current limit value (I _lim ) based on the basic γδ axis current command value (I _γ0 ^* , I _δ0 ^* ). The expanded current limit value (I _lim ) calculated by the expanded current limit value calculation unit 35 is output to the current command value calculation unit 36. The current command value limiter 36 limits the current command value or the basic current command value calculated by the magnetic flux response compensator 32 with the expanded current limit value (I _lim ). Then, the command values (I _γ ^* , I _δ ^* ) calculated by the current command value limiting unit 36 are output to the subtractor 41 and the like (see FIG. 3). The configuration of the current command value limiting unit 36 will be described later (see FIGS. 6 and 7).

  Next, the configuration of the enlarged current limit value calculation unit 35 will be described with reference to FIG. FIG. 5 is a block diagram of the enlarged current limit value calculation unit 35.

  As shown in FIG. 5, the expanded current limit value calculation unit 35 includes a basic current amplitude calculation unit 351, a rated current limit unit 352, an expanded current amplitude calculation unit 353, and a limit current limit unit 354.

The basic current amplitude calculation unit 351 is obtained from the sum of a vector indicating the basic γ current command value (I _γ0 ^* ) and a vector indicating the basic δ current command value (I _δ0 ^* ), as shown in Expression (6). The amplitude (I _S0 ^* ) of the basic current command value is calculated and output to the rated current limiter 352.

The rated current limiter 352 calculates the rated current limit amplitude (I _{S0_rat} ^* ) by limiting the amplitude (I _S0 ^* ) of the input basic current command value with the rated current limit value (I _rat ^* ). And output to the enlarged current amplitude calculator 353. The rated current limit value ( _I.sub.rat ^* ) is a maximum current value that allows a current to continuously flow through the switching element for several tens of seconds or several minutes in consideration of the configuration and characteristics such as the impedance of the inverter 2 and the motor 3. Positive and negative maximum current values), which are values set in advance by design or experiment. The rated current limit value (I _rat ^* ) is defined by an upper limit value and a lower limit value.

Rated current limiting unit 352, the amplitude _{(I S0} ^*) in the case where the rated current limit of the upper limit _{(+ I rat} ^*) above is the rated current limit of the upper limit _{(+ I rat} ^*) the rated current limit amplitude (I _{S0_rat} ^* ) is calculated. Rated current limiting unit 352, the amplitude _{(I S0} ^*) in the case is less than the rated current limit of the lower limit _{(-I rat} ^*) is the rated current limit of the lower limit _{(-I rat} ^*) the rated current limit amplitude Calculate as (I _{S0 — rat} ^* ). In addition, the rated current limit unit 352 has an amplitude (I _S0 ^* ) higher than the lower limit rated current limit value (−I _rat ^* ) and lower than the upper limit rated current limit value (+ I _rat ^* ). The amplitude (I _S0 ^* ) is calculated as the rated limiting current amplitude (I _{S0 — rat} ^* ).

ただし、Ｇ_ｓ（ｓ）はモータ３のロータ磁束の伝達関数のモデルを示し、Ｇ_φ（ｓ）はインバータ２のスイッチング素子の熱応答関数のモデルを示す。 As shown in Expression (7), the expanded current amplitude calculation unit 353 uses the rated limited current amplitude (I _{S0 — rat} ^* ), the transfer function (G _s (s)) of the rotor magnetic flux, and the thermal response function of the switching element of the inverter 2. By multiplying the ratio with (G _φ (s)), the enlarged current amplitude (I _{s0 — bst} ^* ) is calculated and output to the limit current limiting unit 354.

Here, G _s (s) represents a model of the transfer function of the rotor magnetic flux of the motor 3, and G _φ (s) represents a model of the thermal response function of the switching element of the inverter 2.

Further, when the response of the rotor magnetic flux and the thermal response of the switching element are approximated by a first-order lag function, the enlarged current amplitude calculation unit 353 calculates the rated limit current amplitude (I _{S0 — rat} ^* ) as shown in Expression (8). _Is multiplied by a function including the response time constant (τ _s ) of the rotor magnetic flux and the thermal time constant (τ _φ ) of the switching element to calculate the expanded current amplitude (I _{s0 — bst} ^* ).

Here, there is a relationship of τ _φ <τ _s between the response time constant of the rotor magnetic flux and the thermal time constant of the switching element. Therefore, the enlarged current amplitude calculation unit 353 functions as a phase advance compensator, and compensates the phase so that the response of the thermal time constant of the switching element becomes the response of the time constant of the rotor magnetic flux.

The rated current limit (I _{S0_rat} ^* ) is limited by the rated current limit value (I _rat ^* ), so that a steady current corresponding to the current amplitude (I _{S0_rat} ^* ) can be applied for several tens of seconds or several minutes. Even when the current flows through the switching element (rated time), the temperature of the switching element can be suppressed to a temperature lower than the limit temperature of the switching element (upper limit temperature for preventing an abnormality of the switching element due to overheating). In addition, since the switching element has a thermal time constant (generally about several seconds), even if the switching element current is increased transiently, the temperature of the switching element increases with a quick response to a current change. There is nothing. Therefore, if the temperature rise of the switching element can be made faster than the steady state while converging to the temperature of the switching element at the rated current in a steady state, a current higher than the rated current is instantaneously applied to the switching element. It can flow.

In this example, from the thermal time constant of the switching element, the current limit value of the switching element is increased from the steady current to transiently increase the current limit value. Specifically, the rated limited current amplitude (I _{S0 — rat} ^* ) is increased to the expanded current amplitude (I _{s0 — bst} ^* ) by phase compensation by the expanded current amplitude calculator 353. As a result, in this example, it is possible to flow an exciting current for sharply exciting the rotor magnetic flux or a transient torque current for enhancing the torque response while maintaining the temperature of the switching element below the limit temperature.

The limit current limiting unit 354 calculates an expanded current limit value (I _lim ^* ) by limiting the input expanded current amplitude (I _{s0_bst} ^* ) with the limit current limit value (I _sat ), and a current command Output to the value control unit 36.

The limit current limit value (I _sat ) indicates a limit value of an instantaneous value of current that cannot be effectively generated for the motor 3. For example, even if the motor is controlled with a high current command value as an instantaneous value, there is a case where torque corresponding to the command value cannot be output from the motor 3 due to the magnetic saturation of the motor or an overcurrent threshold determined by hardware. is there. Therefore, in this example, the instantaneous value of the current that cannot generate an effective torque for the motor 3 is set as the limit current limit value (I _sat ). The limit current limit value (I _sat ) may be a current limit value that protects the motor 3 or the inverter 2 from an instantaneous overcurrent. From the viewpoint of protection of the inverter 2 or the motor 3, a current limit value is provided even for an instantaneous value.

Thereby, the expanded current limit value calculation unit 35 is set based on the thermal time constant of the switching element, and calculates an expanded current limit value (I _lim ^* ) higher than the rated current of the switching element.

Further, the extended current limit value (I _lim ^* ) will be described. The rated time is a time set in advance by design and time according to the thermal time constant of the switching element. The time during which the current higher than the steady current can flow through the switching element within the rated time is determined according to the upper limit value of the set current and the thermal time constant of the switching element. Therefore, the expanded current limit value (I _lim ^* ) is the threshold temperature when the current higher than the rated current of the switching element is passed through the switching element for a time corresponding to the thermal time constant (τ _φ ). The upper limit value of current is expressed as follows.

  Next, the configuration of the current command value limiting unit 36 will be described with reference to FIGS. 6 and 7 are block diagrams showing the configuration of the current command value control unit 36. FIG. The current command value control unit 36 includes rated current limiting units 361 and 364, an expanded excitation current limit value calculating unit 362, an excitation current limiting unit 363, an expanded torque current limit value calculating unit 365, and a torque current limiting unit 366. Yes.

Based on the determination result of the enlarged current command value determining unit 34, the current command value limiting unit 36 uses either the configuration shown in FIG. 6 or the configuration shown in FIG. _(γ ^* , I _δ ^* ) is calculated. If the enlarged current command value determination unit 34 determines that the change amount (dI _γ0 ^* ) of the basic γ-axis current command value is larger than the determination threshold value (I ₀ ), the current command value control unit 36 The limit value of the excitation current command value is expanded to the expanded excitation current limit value (I _{γ_lim} ) by the rated current limit unit 361, the expanded excitation current limit value calculation unit 362, and the excitation current limit unit 363 shown in FIG.

On the other hand, when the enlarged current command value determining unit 34 determines that the change amount (dI _γ0 ^* ) of the basic γ-axis current command value is equal to or less than the determination threshold value (I ₀ ), the current command value limiting unit 36 7, the limit value of the torque current command value is expanded to the expanded torque current limit value (I _{δ_lim} ) by the rated current limit unit 364, the expanded torque current limit value calculation unit 365, and the torque current limit unit 366. .

As shown in FIG. 6, the rated current limiting unit 361 limits the input basic δ-axis current command value (I _δ0 ^* ) with the rated current limit value (I _rat ^* ), thereby providing a δ-axis current command. The value (I _δ ^* ) is calculated. Rated current limit value _{(I rat} ^*) may be used rated current limit value used in the rated current limiting unit 352 _{(I rat} ^*).

The expanded excitation current limit value calculation unit 362 subtracts the magnitude of the δ-axis current command value (I _δ ^* ) from the magnitude of the expanded current limit value (I _lim ), as shown in Expression (9). Then, the enlarged excitation current limit value (I _{γ_lim} ) is calculated.

The excitation current limiting unit 363 limits the magnetic flux compensation γ-axis current command value (I _γ1 ^* ) compensated by the magnetic flux response compensation unit 32 with an expanded excitation current limit value (I _{γ_lim} ), thereby _obtaining a γ-axis current command. The value (I _γ ^* ) is calculated.

As shown in FIG. 7, the rated current limiting unit 364 limits the magnetic flux compensation γ-axis current command value (I _γ1 ^* ) compensated by the magnetic flux response compensation unit 32 with the rated current limiting value (I _rat ^* ). Thus, the γ-axis current command value (I _γ ^* ) is calculated. Rated current limit value _{(I rat} ^*) may be used rated current limit value used in the rated current limiting unit 352 _{(I rat} ^*).

The expanded torque current limit value calculation unit 363 expands by subtracting the magnitude of the γ-axis current command value (I _γ ^* ) from the expanded current limit value (I _lim ), as shown in Expression (10). A torque current limit value (I _{δ_lim} ) is calculated.

The torque current limiter 363 calculates the δ-axis current command value (I _δ ^* ) by limiting the basic δ-axis current command value (I _δ0 ^* ) with the expanded torque current limit value (I _{δ_lim} ).

  Next, control of the expansion current limit value calculation unit 35 and the current command value limit unit 36 will be described with reference to FIGS.

  As described above, the excitation response compensator 32 compensates the excitation current command value by amplifying the excitation current command value so as to advance the phase of the excitation current command value in order to increase the response speed of the excitation current. .

  When the excitation current is supplied up to the maximum current limit value with respect to the amplified excitation current command value, a transiently large excitation current is caused by the advance compensation. However, from the viewpoint of protection against overcurrent to the motor, a current exceeding the maximum current limit value cannot flow through the motor. If this maximum current limit value is set to the rated current (unlike this example), an exciting current exceeding the rated current cannot flow. Furthermore, if control is performed so that the command value is preferentially distributed to the excitation current, all current flows to the excitation current, and torque current does not flow. As a result, torque cannot be generated when the torque current becomes zero while the magnetic flux of the rotor is insufficient, and the torque response is delayed.

Therefore, the expanded current limit value calculation unit 35 increases the limit value of the current command value to the expanded current limit value (I _lim ). The expanded current limit value (I _lim ) is a value set based on the thermal time constant of the switching element, and is a current value higher than the rated current of the switching element. Further, due to the relationship between the thermal time constant of the switching element and the time constant of the rotor magnetic flux, the thermal response speed of the switching element is slower than the response speed of the rotor magnetic flux. Therefore, the rotor magnetic flux can be increased before the temperature of the switching element reaches the limit temperature by flowing a transiently high excitation current within a range equal to or smaller than the expanded current limit value (I _lim ). Thereby, the present example increases the magnetic flux response of the rotor.

Further, when enlarging the limit value of the excitation current, the current command value limiting unit 36 calculates the expanded excitation current limit value (I _{γ_lim} ) based on the torque current command value, and then calculates the excitation current command value. It is limited by the expanded excitation current limit value (I _{γ_lim} ). When enlarging the torque current limit value, the current command value limiter 36 calculates an enlarged torque current limit value (I _{δ_lim} ) based on the excitation current command value, and then _converts the torque current command value to the expanded torque. It is limited by the current limit value (I _{δ_lim} ). This prevents the limit value from being increased until the excitation current or the torque current becomes zero, so that the generated torque is prevented from becoming zero.

  Next, the control procedure of the motor controller 20 will be described with reference to FIG. FIG. 8 is a flowchart showing a control procedure of the motor controller 20. The control flow in FIG. 8 is repeatedly executed at a predetermined cycle.

In step S1, the motor controller 20, the vehicle speed, the accelerator opening, etc. are acquired as input processing. In step S2, the motor torque control unit 21 calculates a torque command value (T _m1 ^* ) based on the input accelerator opening and the like. In step S _<b ^{> 3} , the vibration suppression control unit 22 calculates the post-vibration control torque command value (T _m2 ^* ) by performing vibration suppression control based on the torque command value (T _m1 ^* ) or the like.

In step S4, the current command value calculator 30 included in the current control unit 23 calculates the γδ-axis current command value (I _γ ^* , I _δ ^* ) based on the post-damping control torque command value (T _m2 ^* ) or the like. Is calculated. The detailed control procedure of step S4 will be described later.

In step S5, a drive signal (switching signal) is generated so that the γδ axis current command value (I _γ ^* , I _δ ^* ) is output from the motor 3 by the subtractor 41 included in the current control unit 23. Then, by outputting to the inverter 2, the inverter 2 is controlled and the motor 3.

  Next, the control procedure of step S4 will be described with reference to FIG. FIG. 9 is a flowchart showing the control procedure of step S4.

After the control in step S3, in step S41, the basic current command value calculation unit 31 determines the basic γδ axis current command value (I _γ0 ^* , I _δ0 ) based on the post-vibration control torque command value (T _m2 ^* ) or the like. ^* ) Is calculated. In step S42, the magnetic flux response compensator 32 amplifies the basic γ-axis current command value (I _γ0 ^* , I _δ0 ^* ) to compensate for the delay in the rotor magnetic flux response of the drive motor 3, and to compensate the magnetic flux compensation γδ axis The current command value (I _γ1 ^* , I _δ1 ^* ) is calculated.

In step S43, the excitation current command value change amount calculation unit 33 calculates the change amount (dI _γ0 ^* ) of the γ-axis current command value based on the magnetic flux compensation γ-axis current command value (I _γ1 ^* ). In step S44, the enlarged current command value determination unit 34 compares the change amount (dI _γ0 ^* ) of the γ-axis current command value with the determination threshold value (I ₀ ).

When the change amount (dI _γ0 ^* ) of the γ-axis current command value is larger than the determination threshold value (I ₀ ), the current command value limiter 36 enlarges the limit value of the excitation current, and determines the excitation current command value and the torque current. A command value is calculated (step S45). On the other hand, when the change amount (dI _γ0 ^* ) of the γ-axis current command value is equal to or less than the determination threshold value (I ₀ ), the current command value limiter 36 enlarges the limit value of the torque current to increase the excitation current command value. The torque current command value is calculated (step S46). Then, when the control of step S45 and step S46 is finished, the control flow of step S4 is finished, and the process proceeds to step S5.

  Next, the control procedure of step S45 will be described with reference to FIG. FIG. 10 is a flowchart showing the control procedure of step S45.

In the control of step S45, first, in step S451, the basic current amplitude calculator 351 calculates the amplitude (I _S0 ^* ) of the basic current command value based on the basic γδ axis current command value (I _γ0 ^* , I _δ0 ^* ). Calculate. In step S452, the rated current limiting unit 352, by applying a limit in the amplitude of the fundamental current command value _{(I S0} ^*) to the rated current limit value _{(I rat} ^*), the rated current limit amplitude _{(I S0_rat} ^*) Calculate. In step S453, enlarged current amplitude calculation section 353, based on the rated current limit amplitude _{(I S0_rat} ^*), calculates the expansion current amplitude _{(I s0_bst} ^*).

In step S454, the limit current limiting unit 354 calculates the expanded current limit value (I _lim ^* ) by limiting the expanded current amplitude (I _{s0_bst} ^* ) with the limit current limit value (I _sat ).

In step S455, the rated current limiting unit 361 limits the basic δ-axis current command value (I _δ0 ^* ) with the rated current limit value (I _rat ^* ), thereby making the δ-axis current command value (I _δ ^*). ) Is calculated. In step S456, the expanded excitation current limit value calculation unit 362 calculates the expanded excitation current limit value (I _{γ_lim} ) based on the expanded current limit value (I _lim ^* ) and the δ-axis current command value (I _δ ^* ). . In step S457, the excitation current limiting unit 363 limits the magnetic flux compensation γ-axis current command value (I _γ1 ^* ) with the expanded excitation current limit value (I _{γ_lim} ), thereby _obtaining the γ-axis current command value (I _γ ^* ) Is calculated.

  Next, the control procedure of step S46 will be described with reference to FIG. FIG. 11 is a flowchart showing the control procedure of step S46. The control flow of steps S461 to S454 is the same as the control flow of steps S451 to S454 shown in FIG.

In step S465, the rated current limiting unit 364 limits the magnetic flux compensation γ-axis current command value (I _γ1 ^* ) with the rated current limit value (I _rat ^* ), thereby obtaining the γ-axis current command value (I _γ ^* ) Is calculated. In step S466, the enlarged torque current limit value calculation unit 365 calculates the enlarged torque current limit value (I _{δ_lim} ) based on the enlarged current limit value (I _lim ^* ) and the γ-axis current command value (I _γ ^* ). . In step S457, the torque current limiting unit 366 limits the δ-axis current command value (I _δ ^* ) by limiting the basic δ-axis current command value (I _δ0 ^* ) and the expanded torque current limit value (I _{δ_lim} ). Is calculated.

  Next, the effect of the motor control device according to the present invention will be described with reference to FIGS. FIG. 12 shows the characteristics of the comparative example, and FIG. 13 shows the characteristics of the present invention. 12 and 13, (a) shows the time characteristic of the excitation current (γ-axis current), (b) shows the time characteristic of the torque current (δ-axis current), (c) shows the time characteristic of the rotor magnetic flux, (d ) It is a graph showing the time characteristics of torque. In FIGS. 12 and 13, the actual torque, the actual γ-axis current, and the actual δ-axis current indicate the actual output torque of the motor 3 and the current that actually flows through the motor 3.

  In the comparative example, similarly to the magnetic flux response compensation unit 32, phase compensation for improving the rotor magnetic flux response is performed by amplifying the γ-axis current command value. The excitation current command value compensated by this phase compensation is limited by the rated current limit value.

  Hereinafter, the torque response performance will be described by taking as an example a case where the torque command value is increased stepwise from the stop state in starting acceleration or the like while comparing FIGS.

  At time t1, as a start acceleration from the stop state, the torque command value rises stepwise, and the basic γδ axis current command value also rises stepwise. By the phase compensation for improving the rotor magnetic flux response by the magnetic flux response compensator 32, the magnetic flux compensation γ-axis current command value shows a transiently large value.

In the comparative example, the excitation current is amplified so that the current is distributed to the γ-axis current as compared to the δ-axis current after the rated current limit value is set to the upper limit value of the current amplitude. Therefore, in the comparative example, the current up to the rated current limit value is used up only by the γ-axis current command value, the current value that can be used for the δ-axis current remains zero, and the dead time during which torque cannot be generated (Corresponding to Δt _n in FIG. 10). Further, since the γ-axis current is limited by the rated current limit value, a desired current for improving the rotor magnetic flux response does not flow, and the desired rotor magnetic flux response cannot be realized.

  At a time between time t1 and t2, when the magnetic flux compensation γ-axis current command value decreases and falls below the rated current limit value, the δ-axis current can flow and the torque starts to rise. .

  At time t2, the rotor magnetic flux rises to about 70 to 80% of the steady value, but the magnetic flux compensation γ-axis current command value almost converges to the basic γ-axis current command value. After time t2, the γ-axis current is maintained at a constant value, and the rotor magnetic flux rises with a delay of a time constant determined by the characteristics of the rotor. As a result, the response speed is slow and the torque response is slow, and it takes time from time t5 to time t6 to converge to the final actual torque command value.

  In the present invention, at time t1, the torque command value rises stepwise, and the basic γδ-axis current command value also rises stepwise. Regarding the δ-axis current, the present invention allows the δ-axis current to flow while limiting the δ-axis current command value with the rated current limit value. For this reason, during the period when the dead time is generated in the comparative example, the present invention does not cause the δ-axis current command value to become zero, and can quickly raise the δ-axis current. As a result, the torque also rises from time t1 without wasted time.

  Further, with respect to the γ-axis current, the magnetic flux compensation γ-axis current command value rises to a transiently large value by the phase compensation for improving the rotor magnetic flux response by the magnetic flux response compensator 32. Since the limit value applied to the flux compensation γ-axis current command value is expanded to the expanded current limit value, a transiently large excitation current is applied compared to the comparative example in which the rated current limit value is limited. It can flow.

As a result, the torque response immediately after time t1 is faster than the comparative example without generating dead time. Also at the point of time t _2, the rotor flux can be launched to about 95% with respect to the command value, as a result, the present invention can greatly improve the torque response.

  As described above, this example calculates the magnetic flux compensation current command value while compensating for the delay in the rotor magnetic flux response of the motor 3 by amplifying the basic current command value, and sets the magnetic flux compensation current command value as an expanded current limit value. The expanded current limit value is set based on the thermal time constant of the switching element, and the current value is higher than the rated current of the switching element. As a result, the temperature of the switching element can be maintained within the limit temperature while transiently increasing the current limit value, so that a large excitation current that causes the rotor magnetic flux to be excited sharply can flow. As a result, the torque response can be increased while the torque response is improved.

In this example, the basic current command value is limited by the rated current limit value (I _rat ^* ) to calculate the rated current limit (equivalent to _{IS0_rat} ^* ), and the expanded current amplitude is calculated based on the rated current limit value. (I _{s0_bst} ^* ) is calculated, and the expanded current limit value (I _lim ^* ) is calculated based on the expanded current amplitude (I _{s0_bst} ^* ). The basic current command value, the rated current limit value, and the expanded current amplitude (I _{s0 — bst} ^* ) satisfy the relationships of Expressions (6) and (7). As a result, the transient current can be allowed within the expanded current amplitude (I _{s0_bst} ^* ), and it can converge to the rated current in the steady state. Therefore, the responsiveness of the torque current is improved while improving the responsiveness of the rotor magnetic flux. Can be increased. Furthermore, the temperature of the switching element can be suppressed below the limit temperature.

The present embodiment, by applying the restriction at the rated current limit amplitude _{(I S0_rat} ^*) the rated current limit value _{(I rat} ^*), calculates the expansion current limit. Then, the limit value of the instantaneous value of the current that cannot generate the effective torque for the motor 3 is set to the rated current limit value (I _rat ^* ). It is inefficient to increase the current value to be expanded transiently to a value at which effective torque cannot be generated. Therefore, in this example, by setting the limit value of the current value to be transiently expanded to the rated current limit value (I _rat ^* ), the efficiency of the inverter 2, the motor 3, etc. is improved, and the switching element in the transient state Is kept below the limit temperature.

The present embodiment, by applying the restriction at the rated current limit amplitude _{(I S0_rat} ^*) the rated current limit value _{(I rat} ^*), calculates the expansion current limit. The limit value that protects the inverter 2 or the motor 3 from an instantaneous overcurrent is set to the rated current limit value (I _rat ^* ). If the enlarged current limit value is increased without limitation, an excessive load may be applied to the inverter 2 and the motor 3. Therefore, in this example, by setting the limit value of the current value to be transiently expanded to the rated current limit value (I _rat ^* ), the temperature of the switching element in the transient state is protected while protecting the inverter 2 and the motor 3. Is kept below the limit temperature.

  In this example, either one of the excitation current command value and the torque current command value is limited by the expanded current command value in accordance with the change amount of the excitation current command value. When the output torque of the motor 3 is set to zero and current is supplied to the inverter 2, the current concentrates on a certain phase of the inverter 2. For this reason, the current allowed when the output torque is zero is smaller than the maximum current allowed when the motor 3 rotates. In this example, when the change amount of the excitation current command value is small, the limit value of the excitation current is not expanded, so that the excitation current can be suppressed to be equal to or less than the allowable current when the output torque is zero. As a result, this example can protect the inverter 2.

Further, in this example, when the change amount of the excitation current command value is higher than the determination threshold (I ₀ ), the excitation current command value is limited by the expanded current limit value, and the torque current command value is limited by the rated current limit value. . When the change amount of the excitation current command value is lower than the determination threshold value (I ₀ ), the torque current command value is limited by the expanded current limit value, and the excitation current command value is limited by the rated current limit value. Thus, when the amount of change in the excitation current is large, the rise of the magnetic flux can be accelerated and the torque response can be increased by transiently increasing the excitation current. When the change amount of the excitation current is small, the excitation current does not exceed the steady current, and the torque current becomes transiently high. Therefore, when it is not necessary to increase the limit value of the excitation current, the torque response can be increased by increasing the torque current.

In this example, when the change amount of the excitation current command value is higher than the determination threshold (I ₀ ), the magnitude of the torque current command value is subtracted from the magnitude of the enlarged current limit value (I _lim ). The γ-axis expanded current limit value (I γ — _lim ) is calculated. When the change amount of the excitation current command value is lower than the determination threshold (I ₀ ), the magnitude of the excitation current command value is subtracted from the magnitude of the enlarged current limit value (I _lim ), thereby expanding the δ axis. A current limit value (I _{δ_lim} ) is calculated. Thereby, the limit value of the excitation current can be increased without setting the torque current to zero, and the limit value of the torque current can be increased without setting the excitation current to zero. As a result, it is possible to prevent occurrence of a dead time when the torque becomes zero.

  The basic current command value calculator 31 corresponds to the “current command value calculator” of the present invention, the magnetic flux response compensator 32 is the “compensator” of the present invention, and the current command value limiter 36 is “ In the "expanded current command value limiting means", the current FB controller 42, the PWM converter 44, etc. are rated as "control means" of the present invention, and the expanded current limit value calculation unit 35 is rated as "limit value calculating means" in the present invention. The current limiter 352 is the “first limiter” of the present invention, the enlarged current amplitude calculator 353 is the “first current limit value calculator”, the limit current limiter 354 is the “second limiter”, the rated current The limiting units 361 and 364 correspond to “third limiting unit”.

DESCRIPTION OF SYMBOLS 20 ... Motor controller 21 ... Motor torque control part 22 ... Damping control part 23 ... Current control part 30 ... Current command value calculator 31 ... Basic current command value calculation part 32 ... Magnetic flux response compensation part 33 ... Excitation current command value change amount Calculation unit 34 ... Expanded current command value determination unit 35 ... Expanded current limit value calculation unit 351 ... Basic current amplitude calculation unit 352 ... Rated current limit unit 353 ... Expanded current amplitude calculation unit 354 ... Limit current limit unit 36 ... Current command value limit Units 361, 364 ... Rated current limiting unit 362 ... Expanded excitation current command value calculating unit 363 ... Excitation current limiting unit 365 ... Expanded torque current command value calculating unit 366 ... Torque current limiting unit

Claims (8)

In a motor control device for controlling an inverter provided with a switching element and a motor connected to the inverter,
Current command value calculation means for calculating a basic current command value based on a torque command value input from the outside and the rotational speed of the motor;
Compensating means for compensating for a delay in the rotor magnetic flux response of the motor by amplifying the basic current command value;
Expanded current command value limiting means for limiting the current command value calculated by the compensation means with an expanded current limit value;
Control means for controlling on and off of the switching element based on the command value limited by the enlarged current command value limiting means;
The expanded current limit value is set based on a thermal time constant of the switching element, and is a current value higher than a rated current of the switching element. The motor control device according to claim 1,
Limit value calculating means for calculating the expanded current limit value based on the first current limit value,
The limit value calculating means includes:
First limiting means for limiting the basic current command value with a rated current limit value;
A motor control device comprising first current limit value calculating means for calculating the first current limit value based on a rated limit current value calculated by the first limit means.
However,

_IS0 ^* indicates the basic current command value,
I _γ0 ^* indicates an excitation current command value included in the basic current command value,
I _δ0 ^* indicates a torque current command value included in the basic current command value,
I _{S0 — bst} ^* indicates the first current limit value;
I _{S0_rat} ^* indicates the rated current limit value,
G _s (s) is a model indicating a thermal response function of the switching element,
G _φ (s) is a model showing the transfer characteristics of the rotor magnetic flux of the motor,
The rated current limit value indicates a limit value of a current that allows a current to constantly flow through the inverter or the motor for a predetermined period. The motor control device according to claim 2,
The limit value calculating means includes:
Having a second limiting means for limiting the first current limit value with a second current limit value, and calculating the expanded current limit value based on the current value limited by the second limit means;
The motor control device according to claim 2, wherein the second current limit value indicates a limit value of an instantaneous value of current at which an effective torque cannot be generated for the motor. The motor control device according to claim 2,
The limit value calculating means includes:
Having a second limiting means for limiting the first current limit value with a second current limit value, and calculating the expanded current limit value based on the current value limited by the second limit means;
The second current limit value indicates a current limit value that protects the motor or the inverter from an instantaneous overcurrent. The motor control device according to any one of claims 1 to 4,
The enlarged current command value limiting means is
According to the change amount of the basic current command value, one of the excitation current command value and the torque current command value included in the basic current command value is limited by the expanded current limit value. Motor control device. The motor control device according to any one of claims 1 to 5,
Further comprising third limiting means for limiting the basic current command value with a rated current limit value;
The rated current limit value indicates a limit value of a current that can flow a current to the inverter or the motor for a predetermined period of time,
The control means includes
Based on the command value limited by the third limiting means, the switching element is controlled,
When the change amount of the excitation current command value included in the basic current command value is higher than a predetermined current threshold,
The expanded current command value limiting means limits the excitation current command value with the expanded current limit value, and the third limiting means converts the torque current command value included in the basic current command value with the rated limited current value. Limit
When the change amount of the excitation current command value included in the basic current command value is lower than a predetermined current threshold,
The expanded current command value limiting means limits the torque current command value with the expanded current limit value, and the third limiting means limits the excitation current command value with the rated limit current value. Motor control device. The motor control device according to any one of claims 1 to 6,
Limit value calculating means for calculating the expanded current limit value for the current axis of either the excitation current command value or the torque current command value included in the basic current command value,
The compensation means includes
Compensate the excitation current command value included in the basic current command value,
When the change amount of the excitation current command value included in the basic current command value is higher than a predetermined current threshold,
The limit value calculating means includes:
By subtracting the magnitude of the torque current command value from the magnitude of the enlarged current limit value, the enlarged current limit value for the current axis of the excitation current is calculated,
When the change amount of the excitation current command value included in the basic current command value is lower than a predetermined current threshold,
The limit value calculating means includes:
A motor that calculates an expanded current limit value for the current axis of the torque current by subtracting the magnitude of the excitation current command value calculated by the compensation means from the size of the expanded current limit value. Control device. The motor control device according to claim 1,
The expanded current limit value is
When a current higher than the rated current of the switching element is passed through the switching element for a time corresponding to the thermal time constant of the switching element, the temperature limit value of the switching element is set to be equal to or lower than the limit temperature of the element. The motor control apparatus characterized by showing.

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